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Sample records for age adeep-ultraviolet resonance

  1. On the Increasing Fragility of Human Teeth with Age: ADeep-Ultraviolet Resonance Raman Study

    Energy Technology Data Exchange (ETDEWEB)

    Ager III, J.W.; Nalla, R.K.; Balooch, G.; Kim, G.; Pugach, M.; Habelitz, S.; Marshall, G.W.; Kinney, J.H.; Ritchie, R.O.

    2006-07-14

    Ultraviolet resonance Raman spectroscopy (UVRRS) using 244nm excitation was used to investigate the impact of aging on humandentin. The intensity of a spectroscopic feature from the peptide bondsin the collagen increases with tissue age, similar to a finding reportedpreviously for human cortical bone.

  2. On the Ages of Resonant, Eroded and Fossil Asteroid Families

    CERN Document Server

    Milani, A; Spoto, F; Cellino, A; Novaković, B; Tsirvoulis, G

    2016-01-01

    In this work we have estimated 10 collisional ages of 9 families for which for different reasons our previous attempts failed. In general, these are difficult cases that required dedicated effort, such as a new family classifications for asteroids in mean motion resonances, as well as a revision of the classification inside the $3/2$ resonance. Of the families locked in mean motion resonances, we succeeded in determining ages of the families of (1911) Schubart and of the "super-Hilda" family, assuming this is actually a severely eroded original family of (153) Hilda. In the Trojan region we found families with almost no Yarkovsky evolution, for which we could compute only physically implausible ages. Hence, we interpreted their modest dispersions of proper eccentricities and inclinations as implying that the Trojan asteroid families are fossil families, frozen at their proper elements determined by the original ejection velocity field. We have found a new family, among the Griquas locked in the 2/1 resonance ...

  3. High-field proton magnetic resonance spectroscopy reveals metabolic effects of normal brain aging.

    Science.gov (United States)

    Harris, Janna L; Yeh, Hung-Wen; Swerdlow, Russell H; Choi, In-Young; Lee, Phil; Brooks, William M

    2014-07-01

    Altered brain metabolism is likely to be an important contributor to normal cognitive decline and brain pathology in elderly individuals. To characterize the metabolic changes associated with normal brain aging, we used high-field proton magnetic resonance spectroscopy in vivo to quantify 20 neurochemicals in the hippocampus and sensorimotor cortex of young adult and aged rats. We found significant differences in the neurochemical profile of the aged brain when compared with younger adults, including lower aspartate, ascorbate, glutamate, and macromolecules, and higher glucose, myo-inositol, N-acetylaspartylglutamate, total choline, and glutamine. These neurochemical biomarkers point to specific cellular mechanisms that are altered in brain aging, such as bioenergetics, oxidative stress, inflammation, cell membrane turnover, and endogenous neuroprotection. Proton magnetic resonance spectroscopy may be a valuable translational approach for studying mechanisms of brain aging and pathology, and for investigating treatments to preserve or enhance cognitive function in aging.

  4. Age of an Indonesian Fossil Tooth Determined by Electron Paramagnetic Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bogard, JS

    2004-04-07

    The first fossil hominid tooth recovered during 1999 excavations from the Cisanca River region in West Java, Indonesia, was associated with a series of bovid teeth from a single individual that was recovered 190 cm beneath the hominid tooth. The age of the fossil bovid teeth was determined using electron paramagnetic resonance (EPR) analysis as part of an effort to bracket the age of the hominid tooth. The EPR-derived age of the bovid teeth is (5.16 {+-} 2.01) x 10{sup 5} years. However, the age estimate reported here is likely an underestimate of the actual age of deposition since evidence of heating was detected in the EPR spectra of the bovid teeth, and the heating may have caused a decrease in the intensity of EPR components on which the age calculation is based.

  5. Cerebellar Volume and Proton Magnetic Resonance Spectroscopy at Term, and Neurodevelopment at 2 Years of Age in Preterm Infants

    Science.gov (United States)

    van Kooij, Britt J. M.; Benders, Manon J. N. L.; Anbeek, Petronella; van Haastert, Ingrid C.; de Vries, Linda S.; Groenendaal, Floris

    2012-01-01

    Aim: To assess the relation between cerebellar volume and spectroscopy at term equivalent age, and neurodevelopment at 24 months corrected age in preterm infants. Methods: Magnetic resonance imaging of the brain was performed around term equivalent age in 112 preterm infants (mean gestational age 28wks 3d [SD 1wk 5d]; birthweight 1129g [SD 324g]).…

  6. Disentangling normal aging from Alzheimer's disease in structural magnetic resonance images.

    Science.gov (United States)

    Lorenzi, Marco; Pennec, Xavier; Frisoni, Giovanni B; Ayache, Nicholas

    2015-01-01

    The morphology observed in the brains of patients affected by Alzheimer's disease (AD) is a combination of different biological processes, such as normal aging and the pathological matter loss specific to AD. The ability to differentiate between these biological factors is fundamental to reliably evaluate pathological AD-related structural changes, especially in the earliest phase of the disease, at prodromal and preclinical stages. Here we propose a method based on non-linear image registration to estimate and analyze from observed brain morphologies the relative contributions from aging and pathology. In particular, we first define a longitudinal model of the brain's normal aging process from serial T1-weight magnetic resonance imaging scans of 65 healthy participants. The longitudinal model is then used as a reference for the cross-sectional analysis. Given a new brain image, we then estimate its anatomical age relative to the aging model; this is defined as a morphological age shift with respect to the average age of the healthy population at baseline. Finally, we define the specific morphological process as the remainder of the observed anatomy after the removal of the estimated normal aging process. Experimental results from 105 healthy participants, 110 subjects with mild cognitive impairment (MCI), 86 with MCI converted to AD, and 134 AD patients provide a novel description of the anatomical changes observed across the AD time span: normal aging, normal aging at risk, conversion to MCI, and the latest stages of AD. More advanced AD stages are associated with an increased morphological age shift in the brain and with strong disease-specific morphological changes affecting mainly ventricles, temporal poles, the entorhinal cortex, and hippocampi. Our model shows that AD is characterized by localized disease-specific brain changes as well as by an accelerated global aging process. This method may thus represent a more precise instrument to identify potential

  7. Age-related changes in intracranial compartment volumes in normal adults assessed by magnetic resonance imaging.

    Science.gov (United States)

    Matsumae, M; Kikinis, R; Mórocz, I A; Lorenzo, A V; Sándor, T; Albert, M S; Black, P M; Jolesz, F A

    1996-06-01

    Magnetic resonance (MR) image-based computerized segmentation was used to measure various intracranial compartments in 49 normal volunteers ranging in age from 24 to 80 years to determine age-related changes in brain, ventricular, and extraventricular cerebrospinal fluid (CSF) volumes. The total intracranial volume (sum of brain, ventricular, and extraventricular CSF) averaged 1469 +/- 102 cm3 in men and 1289 +/- 111 cm3 in women. The difference was attributable primarily to brain volume, which accounted for 88.6% of the respective intracranial volumes in both sexes, but was significantly larger in men (1302 +/- 112 cm3) than in women (1143 +/- 105 cm3). In both, the cranial CSF volume averaged 11.4%. Total intracranial volume did not change with age, although the normalized brain volume of both men and women began to decrease after the age of 40 years. This decrease was best reflected by expansion of the extraventricular CSF volume which, after the age of 50 years, was more marked in men than in women. The volume of the cranial CSF, as determined by MR image-based computerized segmentation, is considerably larger than traditionally accepted and resides mostly extraventricularly. Expansion of CSF volume with age provides a good index of brain shrinkage although evolving changes and growth of the head with age tend to confound the results.

  8. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...

  9. Probing beer aging chemistry by nuclear magnetic resonance and multivariate analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J.A. [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Barros, A.S. [QOPNA-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Carvalho, B.; Brandao, T. [UNICER, Bebidas de Portugal, Leca do Balio, 4466-955, S. Mamede de Infesta (Portugal); Gil, Ana M., E-mail: agil@ua.pt [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)

    2011-09-30

    Graphical abstract: The use of nuclear magnetic resonance (NMR) metabonomics for monitoring the chemical changes occurring in beer exposed to forced aging (at 45 deg. C for up to 18 days) is described. Both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and an aging trend was observed. Inspection of PLS-DA loadings and peak integration revealed the importance of well known markers (e.g. 5-HMF) as well as of other compounds: amino acids, higher alcohols, organic acids, dextrins and some still unassigned spin systems. 2D correlation analysis enabled relevant compound variations to be confirmed and inter-compound correlations to be assessed, thus offering improved insight into the chemical aspects of beer aging. Highlights: {center_dot} Use of NMR metabonomics for monitoring the chemical changes occurring in beer exposed to forced aging. {center_dot} Compositional variations evaluated by principal component analysis and partial least squares-discriminant analysis. {center_dot} Results reveal importance of known markers and other compounds: amino and organic acids, higher alcohols, dextrins. {center_dot} 2D correlation analysis reveals inter-compound relationships, offering insight into beer aging chemistry. - Abstract: This paper describes the use of nuclear magnetic resonance (NMR) spectroscopy, in tandem with multivariate analysis (MVA), for monitoring the chemical changes occurring in a lager beer exposed to forced aging (at 45 deg. C for up to 18 days). To evaluate the resulting compositional variations, both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and a clear aging trend was observed. Inspection of PLS-DA loadings and peak integration enabled the changing compounds to be identified, revealing the importance of well known

  10. A Microwave Ring-Resonator Sensor for Non-Invasive Assessment of Meat Aging

    Directory of Open Access Journals (Sweden)

    Muhammad Taha Jilnai

    2016-01-01

    Full Text Available The assessment of moisture loss from meat during the aging period is a critical issue for the meat industry. In this article, a non-invasive microwave ring-resonator sensor is presented to evaluate the moisture content, or more precisely water holding capacity (WHC of broiler meat over a four-week period. The developed sensor has shown significant changes in its resonance frequency and return loss due to reduction in WHC in the studied duration. The obtained results are also confirmed by physical measurements. Further, these results are evaluated using the Fricke model, which provides a good fit for electric circuit components in biological tissue. Significant changes were observed in membrane integrity, where the corresponding capacitance decreases 30% in the early aging (0D-7D period. Similarly, the losses associated with intracellular and extracellular fluids exhibit changed up to 42% and 53%, respectively. Ultimately, empirical polynomial models are developed to predict the electrical component values for a better understanding of aging effects. The measured and calculated values are found to be in good agreement.

  11. A Microwave Ring-Resonator Sensor for Non-Invasive Assessment of Meat Aging

    Science.gov (United States)

    Jilani, Muhammad Taha; Wen, Wong Peng; Cheong, Lee Yen; ur Rehman, Muhammad Zaka

    2016-01-01

    The assessment of moisture loss from meat during the aging period is a critical issue for the meat industry. In this article, a non-invasive microwave ring-resonator sensor is presented to evaluate the moisture content, or more precisely water holding capacity (WHC) of broiler meat over a four-week period. The developed sensor has shown significant changes in its resonance frequency and return loss due to reduction in WHC in the studied duration. The obtained results are also confirmed by physical measurements. Further, these results are evaluated using the Fricke model, which provides a good fit for electric circuit components in biological tissue. Significant changes were observed in membrane integrity, where the corresponding capacitance decreases 30% in the early aging (0D-7D) period. Similarly, the losses associated with intracellular and extracellular fluids exhibit changed up to 42% and 53%, respectively. Ultimately, empirical polynomial models are developed to predict the electrical component values for a better understanding of aging effects. The measured and calculated values are found to be in good agreement. PMID:26805828

  12. Knee joint examinations by magnetic resonance imaging: The correlation of pathology, age, and sex

    Directory of Open Access Journals (Sweden)

    Serhat Avcu

    2010-01-01

    Full Text Available Aims: The aim of our study was to investigate the incidence and coexistence of multiple knee joint pathologies and the distribution of knee joint pathologies according to age and sex. Patients and Methods: A retrospective analysis was performed using the clinical data of patients evaluated with magnetic resonance imaging (MRI of the knee joint. Data from 308 patients examined between August 2002 and July 2003 were included into this study. A Pearson correlation analysis was performed to examine the relationship between the pathological findings and the age and sex of the patients. Results: The ages of the patients ranged between 1 and 74 years (mean: 43.3 years. Age was significantly correlated with meniscal degeneration and tears, medial collateral ligament degeneration, parameniscal cyst, and chondromalacia patellae. There was a significant correlation between male gender and anterior cruciate ligament injury. Meniscal injury was significantly correlated with bursitis, as well as medial collateral ligament injury. Bone bruise was significantly correlated with medial collateral ligament injury, lateral collateral ligament injury, Baker′s cyst, and anterior cruciate ligament injury. Chondromalacia patellae was significantly correlated with anterior cruciate ligament injury, patellae alta, and osteochondral lesion. Bursitis (in 53.2% of the patients followed by grade-II meniscal degeneration (in 43% of the patients were the most common knee pathologies observed by MRI. Conclusions: MRI findings of select knee pathologies are significantly correlated with each other and the age and sex of the patient.

  13. Knee joint examinations by magnetic resonance imaging: The correlation of pathology, age, and sex

    Directory of Open Access Journals (Sweden)

    Serhat Avcu

    2010-04-01

    Full Text Available Aims: The aim of our study was to investigate the incidence and coexistence of multiple knee joint pathologies and the distribution of knee joint pathologies according to age and sex. Patients and Methods: A retrospective analysis was performed using the clinical data of patients evaluated with magnetic resonance imaging (MRI of the knee joint. Data from 308 patients examined between August 2002 and July 2003 were included into this study. A Pearson correlation analysis was performed to examine the relationship between the pathological findings and the age and sex of the patients. Results: The ages of the patients ranged between 1 and 74 years (mean: 43.3 years. Age was significantly correlated with meniscal degeneration and tears, medial collateral ligament degeneration, parameniscal cyst, and chondromalacia patellae. There was a significant correlation between male gender and anterior cruciate ligament injury. Meniscal injury was significantly correlated with bursitis, as well as medial collateral ligament injury. Bone bruise was significantly correlated with medial collateral ligament injury, lateral collateral ligament injury, Baker’s cyst, and anterior cruciate ligament injury. Chondromalacia patellae was significantly correlated with anterior cruciate ligament injury, patellae alta, and osteochondral lesion. Bursitis (in 53.2% of the patients followed by grade-II meniscal degeneration (in 43% of the patients were the most common knee pathologies observed by MRI. Conclusions: MRI findings of select knee pathologies are significantly correlated with each other and the age and sex of the patient.

  14. Regional age-related effects in the monkey brain measured with 1H magnetic resonance spectroscopy.

    Science.gov (United States)

    Ronen, Itamar; Fan, Xiaoying; Schettler, Steve; Jain, Sahil; Murray, Donna; Kim, Dae-Shik; Killiany, Ronald; Rosene, Douglas

    2011-06-01

    The rhesus monkey is a useful model for examining age-related effects on the brain, because of the extensive neuroanatomical homology between the monkey and the human brain, the tight control for neurological diseases as well as the possibility of obtaining relevant behavioral data and post-mortem tissue for histological analyses. Here, proton magnetic resonance spectroscopy ((1)H-MRS) was used together with high-resolution anatomical MRI images to carefully assess regional concentrations of brain metabolites in a group of 20 rhesus monkeys. In an anterior volume of interest (VOI) that covered frontal and prefrontal areas, significant positive correlations of myo-inositol and of total creatine concentrations with age were detected, whereas N-acetyl aspartate (NAA) and choline compounds (Cho) were not significantly correlated with age. In an occipito-parietal VOI, all metabolites showed no statistically significant age-dependent trend. Strong correlations were found between NAA concentration and gray matter fraction in the VOIs as well as between choline compounds and white matter fraction.

  15. Magnetic resonance imaging of distal tibia and calcaneus for forensic age estimation in living individuals.

    Science.gov (United States)

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Can, Ismail Ozgur; Inci, Ercan; Aksoy, Sema; Bilgili, Mustafa Gokhan

    2015-07-01

    In recent years, methods by which to decrease radiation exposure during age estimation have gained importance and become a main research area in the forensic sciences. Imaging tools such as X-ray and computed tomography (CT) are accepted as the main diagnostic methods for evaluation of the epiphysis in living individuals; however, radiation exposure and superimposition are the main disadvantages of these techniques. Magnetic resonance (MR) imaging provides an advantage in terms of preventing radiation exposure. In this study, we performed an MR analysis of the degree of fusion of the distal tibia and calcaneal epiphysis and investigated the utility of this technique in the Turkish population. Using the three-stage method described by Saint-Martin et al., we retrospectively evaluated 167 MR images (97 males, 70 females; mean age, 17.7 ± 4.8 years for males and 17.6 ± 4.9 years for females; age range of all subjects, 8-25 years). Intraobserver and interobserver evaluation showed good repeatability and consistency of this method. Stages 2 and 3 ossification of the distal tibial epiphysis first occurred at age 14 and 15 years in males and 12 and 14 years in females, respectively. Stages 2 and 3 ossification of the calcaneal epiphysis first occurred at age 14 and 16 years in males and 10 and 12 years in females, respectively. When performed alone, MR analysis of the distal tibial and calcaneal epiphysis offers limited information for forensic age estimation. However, we suggest that MR analysis can be used as a supportive method when it is necessary to avoid repeated radiation exposure.

  16. Aging effects of regional activation in a spatial task A functional magnetic resonance imaging study

    Institute of Scientific and Technical Information of China (English)

    Jong-Rak Park; Dae-Woon Lim; Mi-Hyun Choi; Su-Jeong Lee; Jin-Seung Choi; Hyung-Sik Kim; Jeong-Han Yi; Gye-Rae Tack; Soon-Cheol Chung

    2009-01-01

    BACKGROUND: An increasing number of studies have shown the effects of aging in basic cognitive processing and higher cognitive functions using functional magnetic resonance imaging (fMRI). However, little is known about the aging effects in diverse cognitive abilities, such as spatial learning and reasoning. OBJECTIVE: To investigate the effect of aging on spatial cognitive performance and regional brain activation based on fMRI. DESIGN, TIME, AND SETTING: A block design for fMRI observation. This study was performed at the fMRI Laboratory, Brain Science Research Center, Korea Advanced Institute of Science and Technology from March 2006 to May 2009.PARTICIPANTS: Eight right-handed, male, college students in their 20s (mean age 21.5 years) and six right-handed, male, adults in their 40s (mean age 45.7 years), who graduated from college, participated in the study. All subjects were healthy and had no prior history of psychiatric or neurological disorders. METHODS: A spatial task was presented while brain images were acquired using a 3T fMRI system (ISOL Technology, Korea). The spatial tasks involved selecting a shape that corresponded to a given figure using four examples, as well as selecting a development figure of a diagram. MAIN OUTCOME MEASURES: The accuracy rate (number of correct answers/total number of items×100%) of spatial tasks was calculated. Using the subtraction procedure, the activated areas in the brain during spatial tasks were color-coded by T-score. The double subtraction method was used to analyze the effect of aging between the two age groups (20s versus 40s). RESULTS: The cerebellum, occipital lobe, parietal lobe, and frontal lobe were similarly activated in the two age groups. Increased brain activations, however, were observed in bilateral parietal and superior frontal lobes of the younger group. More activation was observed in bilateral middle frontal and right inferior frontal lobes in the older group. Compared with the older group, the

  17. Abundance of $\\delta$ Resonances in $^{58}Ni$ + $^{58}Ni$ Collisions between 1 and 2 AGeV

    CERN Document Server

    Hong, B H; Ritman, J L; Best, D; Gobbi, A; Hildenbrand, K D; Kirejczyk, M; Leifels, Y; Pinkenburg, C H; Reisdorf, W; Schuell, D; Sodan, U; Wang, G S; Wienold, T; Alard, J P; Amouroux, V; Bastid, N; Belyaev, I; Berek, G; Biegansky, J; Butà, A; Coffin, J P; Crochet, Philippe; Donà, R; Dupieux, P; Eskef, M; Fintz, P; Fodor, Z; Fraysse, L; Genoux-Lubain, A; Goebels, G; Guillaume, G; Haefele, E; Jundt, F; Kecskeméti, J; Korolija, M; Kotte, R; Kühn, C E; Lebedev, A; Legrand, I; Maazouzi, C; Man'ko, V I; Mösner, J; Mohren, S; Neubert, W; Pelte, D; Petrovici, M; Pras, P; Rami, F; Roy, C; Seres, Z; Sikora, B; Simion, V; Siwek-Wilczynska, K; Somov, A; Tizniti, L; Trzaska, M; Vasilev, M A; Wagner, P; Wohlfarth, D; Zhilin, A V

    1997-01-01

    Charged pion spectra measured in 58Ni-58Ni collisions at 1.06, 1.45 and 1.93 AGeV are interpreted in terms of a thermal model including the decay of Delta resonances. The transverse momentum spectra of pions are well reproduced by adding the pions originating from the Delta-resonance decay to the component of thermal pions, deduced from the high transverse momentum part of the pion spectra. About 10 and 18% of the nucleons are excited to Delta states at freeze-out for beam energies of 1 and 2 AGeV, respectively.

  18. Fetal magnetic resonance imaging: exposure times and functional outcomes at preschool age

    Energy Technology Data Exchange (ETDEWEB)

    Bouyssi-Kobar, Marine [George Washington University, Institute for Biomedical Sciences, Washington, DC (United States); Children' s National Health System, Advanced Pediatric Brain Imaging Research Laboratory, Departments of Diagnostic Imaging and Radiology, Washington, DC (United States); Du Plessis, Adre J. [Children' s National Health System, Fetal and Transitional Medicine, Washington, DC (United States); Robertson, Richard L. [Children' s Hospital Boston and Harvard Medical School, Department of Radiology, Boston, MA (United States); Limperopoulos, Catherine [Children' s National Health System, Advanced Pediatric Brain Imaging Research Laboratory, Departments of Diagnostic Imaging and Radiology, Washington, DC (United States); Children' s National Health System, Fetal and Transitional Medicine, Washington, DC (United States)

    2015-11-15

    Fetal magnetic resonance imaging (MRI) has been routinely used as a noninvasive diagnostic tool for more than a decade; however, there is a paucity of follow-up studies examining the effects of prenatal exposure to 1.5-T MRI on developmental outcome. The objective of this study was to assess the safety of 1.5-T fetal MRI by evaluating functional outcomes of preschool children who were exposed in utero. In the context of a prospective observational study, healthy pregnant women underwent a 1.5-T MRI study using single-shot fast spin echo (SSFSE) sequences during the second or third trimester of pregnancy. The study was approved by the institutional review board at our institution, and written informed consent was obtained from all study participants. MRI scanning times were recorded, and prenatal/postnatal clinical data were collected prospectively. Functional outcomes were assessed using the Vineland Adaptive Behavior Scale (VABS), a widely used, norm-referenced and psychometrically sound functional assessment. We studied 72 healthy pregnant women, who underwent fetal MRI at a mean gestational age of 30.5 ± 3.1 weeks. The cohort of fetuses was composed of 43% females, and 18 fetuses were scanned during the second trimester. All fetuses were born at term with appropriate birth weights (3.54 ± 0.5 kg) for gestational age. Mean age at follow-up testing was 24.5 ± 6.7 months. All children had age-appropriate scores in the communication, daily living, socialization and motor skills subdomains of the VABS (z-scores, P > 0.05). Furthermore, all children passed their newborn otoacoustic emission test and had normal hearing at preschool age. MRI study duration and exposure time to radio frequency waves and SSFSE sequences were not associated with adverse functional outcomes or hearing impairment. Prenatal exposure to 1.5-T MRI during the second or third trimester of pregnancy in a cohort of healthy fetuses is not associated with disturbances in functional outcomes or

  19. Magnetic resonance histology of age-related nephropathy in the Sprague Dawley rat.

    Science.gov (United States)

    Xie, Luke; Cianciolo, Rachel E; Hulette, Brian; Lee, Ha Won; Qi, Yi; Cofer, Gary; Johnson, G Allan

    2012-07-01

    Magnetic resonance histology (MRH) has become a valuable tool in evaluating drug-induced toxicity in preclinical models. However, its application in renal injury has been limited. This study tested the hypothesis that MRH could detect image-based biomarkers of chronic disease, inflammation, or age-related degeneration in the kidney, laying the foundation for more extensive use in evaluating drug toxicity. We examined the entire intact kidney in a spontaneous model of chronic progressive nephropathy. Kidneys from male Sprague Dawley rats were imaged at 8 weeks (n = 4) and 52 weeks (n =4) on a 9.4 T system dedicated to MR microscopy. Several potential contrast mechanisms were explored to optimize the scanning protocols. Full coverage of the entire kidney was achieved with isotropic spatial resolution at 31 microns (voxel volume = 30 pL) using a gradient recalled echo sequence. Isotropic spatial resolution of 15 microns (voxel volume kidney volume, pelvis volume, main vessel volume, glomerular size, as well as thickness of the cortex, outer medulla, and inner medulla.

  20. Multimodal quantitative magnetic resonance imaging of thalamic development and aging across the human lifespan: implications to neurodegeneration in multiple sclerosis.

    Science.gov (United States)

    Hasan, Khader M; Walimuni, Indika S; Abid, Humaira; Frye, Richard E; Ewing-Cobbs, Linda; Wolinsky, Jerry S; Narayana, Ponnada A

    2011-11-16

    The human brain thalami play essential roles in integrating cognitive, sensory, and motor functions. In multiple sclerosis (MS), quantitative magnetic resonance imaging (qMRI) measurements of the thalami provide important biomarkers of disease progression, but late development and aging confound the interpretation of data collected from patients over a wide age range. Thalamic tissue volume loss due to natural aging and its interplay with lesion-driven pathology has not been investigated previously. In this work, we used standardized thalamic volumetry combined with diffusion tensor imaging, T2 relaxometry, and lesion mapping on large cohorts of controls (N = 255, age range = 6.2-69.1 years) and MS patients (N = 109, age range = 20.8-68.5 years) to demonstrate early age- and lesion-independent thalamic neurodegeneration.

  1. Magnetic resonance imaging of the cervical spine: Frequency of degenerative changes in the intervertebral disc with relation to age

    Energy Technology Data Exchange (ETDEWEB)

    Abdulkarim, J.A.; Dhingsa, R.; Finlay, D.B.L

    2003-12-01

    AIM: To ascertain the level at which intervertebral disc degeneration of the cervical spine most commonly occurs in each decade from 20-79 years. MATERIALS AND METHODS: Using computer analysis, we retrospectively assessed the mean signal intensity from each cervical disc from T2-weighted spin-echo images in 60 symptomatic patients (10 per decade from the third to eighth inclusive). RESULTS: Age, disc level and interaction between age and level were highly significant predictors for the magnetic resonance imaging (MRI) mean signal intensity from intervertebral discs (p<0.0001 for all three terms). The MRI signals were generally lower as age increased and also for the higher discs (C2-C3, etc). CONCLUSION: In our study we have shown that in younger patients the higher discs are more frequently affected by degeneration than the lower ones. As age increases, the process of degeneration becomes more generalized with less variability between discs.

  2. Automated tissue classification of pediatric brains from magnetic resonance images using age-specific atlases

    Science.gov (United States)

    Metzger, Andrew; Benavides, Amanda; Nopoulos, Peg; Magnotta, Vincent

    2016-03-01

    The goal of this project was to develop two age appropriate atlases (neonatal and one year old) that account for the rapid growth and maturational changes that occur during early development. Tissue maps from this age group were initially created by manually correcting the resulting tissue maps after applying an expectation maximization (EM) algorithm and an adult atlas to pediatric subjects. The EM algorithm classified each voxel into one of ten possible tissue types including several subcortical structures. This was followed by a novel level set segmentation designed to improve differentiation between distal cortical gray matter and white matter. To minimize the req uired manual corrections, the adult atlas was registered to the pediatric scans using high -dimensional, symmetric image normalization (SyN) registration. The subject images were then mapped to an age specific atlas space, again using SyN registration, and the resulting transformation applied to the manually corrected tissue maps. The individual maps were averaged in the age specific atlas space and blurred to generate the age appropriate anatomical priors. The resulting anatomical priors were then used by the EM algorithm to re-segment the initial training set as well as an independent testing set. The results from the adult and age-specific anatomical priors were compared to the manually corrected results. The age appropriate atlas provided superior results as compared to the adult atlas. The image analysis pipeline used in this work was built using the open source software package BRAINSTools.

  3. Magnetic resonance arthrography assessment of the superior labrum using the BLC system: age-related changes mimicking SLAP-2 lesions

    Energy Technology Data Exchange (ETDEWEB)

    Koziak, Adrian [Queen' s School of Medicine, Kingston, Ontario (Canada); Chuang, Michael J.; Jancosko, Jason J.; Nottage, Wesley M. [The Sport Clinic Orthopedic Medical Associates, Inc., Laguna Hills, CA (United States); Burnett, Keith R. [Saddleback Valley Radiology, Laguna Hills, CA (United States)

    2014-08-15

    The purpose of the study was to describe the variation of the superior labrum with increasing age by assessing magnetic resonance (MR) arthrograms. Inclusion criteria were used to include only the MR arthrograms of patients devoid of clinical labral pathology. Two hundred thiry-six MR arthrograms were blindly assessed for biceps-labral complex (BLC) type 1-3 and sublabral recess size by a musculoskeletal radiologist. We have chosen the BLC system, which defines normal superior labral variants, since it is established in the literature and is used by reporting musculoskeletal (MSK) radiologists. The MR arthrograms demonstrated that the majority of patients <40 years old were BLC type 1 and showed a steady increase in BLC types 2 and 3 with increasing age. Assessments demonstrated significantly greater (p < 0.01) mean BLC types (1.62 vs 1.29) and recess size (1.35 vs 0.66 mm) in those over 40 compared with those less than 40 years of age. Furthermore, significant differences (p < 0.05) were noted between mean BLC assessments between different decades of age. There appears to be a physiologic deepening of the superior labrum sulcus with age, which becomes significant after the age of 40. These findings can contribute to whether the superior labrum is considered abnormal when assessed radiographically. The differentiation of normal age-related changes in the shoulder, from those of a type 2 SLAP tear can reduce the rates of unnecessary SLAP-2 repairs. This is the first reported series to use the BLC system; we believe it provides a common nomenclature to allow clear communication between specialists. (orig.)

  4. Magnetic resonance fiber density mapping of age-related white matter changes

    Energy Technology Data Exchange (ETDEWEB)

    Stadlbauer, Andreas, E-mail: andi@nmr.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Ganslandt, Oliver [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Salomonowitz, Erich [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Buchfelder, Michael [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Hammen, Thilo [Department of Neurology, Epilepsy Center, University of Erlangen-Nuremberg, Schwabachanlage 6, D-90429 Erlangen (Germany); Bachmair, Johanna [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Eberhardt, Knut [Krankenhaus Schloss Werneck, MRT-Kompetenzzentrum, Balthasar-Neumann-Platz 1, D-97440 Werneck (Germany)

    2012-12-15

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm{sup 3} isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  5. Normal morphology of sacroiliac joints in children: magnetic resonance studies related to age and sex

    Energy Technology Data Exchange (ETDEWEB)

    Bollow, M.; Paris, S.; Mutze, S.; Hamm, B. [Institut fuer Roentgendiagnostik, Charite, Humboldt-Universitaet zu Berlin, Schumannstrasse 20-21, D-10098 Berlin (Germany); Braun, J.; Kannenberg, J. [Department of General Internal Medicine and Rheumatology, Klinikum Benjamin Franklin, Freie Universitaet Berlin, Berlin (Germany); Biedermann, T.; Schauer-Petrowskaja, C. [Department of Juvenile Rheumatology, II. Kinderklinik, Krankenhaus Berlin Buch, Berlin (Germany)

    1997-12-01

    Objective. To determine in a prospective study the normal MRI morphology of the sacroiliac joints (SIJs) in relation to age and sex during adolescence. Design and patients. A total of 98 children (63 boys, mean age 12.7{+-}2.8 years; 35 girls, mean age 13.7{+-}2.3 years), ranging in age from 8 to 17 years, with juvenile chronic arthritis (JCA) but without signs of sacroiliitis fulfilled the study prerequisites (no back pain and no pathologic changes of the SIJs on physical examination before MRI in a 1.5-year follow-up). An additional eight HLA-B27-negative boys and eight HLA-B27-negative girls without arthritis served as controls. The MRI protocol comprised a T1-weighted SE sequence, an opposed-phase T2*-weighted GE sequence, and a dynamic contrast-enhanced study in single-section technique. Results. Noncontrast MRI permitted differentiation of ``open`` from ossified segmental and lateral apophyses of the sacral wings, with a significant difference in age (P <0.05) between children with open and ossified apophyses. Ossification of the apophyses of the sacral wings was seen significantly earlier (P <0.05) in girls than in boys. Girls also had a significantly higher incidence of transitional lumbosacral vertebrae, pelvic asymmetries, and accessory joints. In the contrast-enhanced opposed-phase MRI study, normal cartilage of the SIJs showed no contrast enhancement whereas the joint capsule showed a moderate enhancement. Conclusion. There are significant age- and sex-related differences in the normal MRI morphology of juvenile SIJs. Our findings might serve as a standard of comparison for the evaluation of pathologic changes - in particular for the early identification of juvenile sacroiliitis. (orig.) With 10 figs., 30 refs.

  6. Collagene order of articular cartilage by clinical magnetic resonance images and its age dependency

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, P.; Gruender, W. [Inst. of Medical Physics and Biophysics, Univ. of Leipzig (Germany)

    2005-07-01

    The present papers describes a novel method to obtain information on the degree of order of the collagen network of the knee meniscal cartilage by means of a single clinical MRI. Images were obtained from 34 healthy volunteers aged between 6 and 76 years as well as from one patient with clinically-diagnosed arthrosis at the age of 32 and 37 years. A siemens vision (1.5 T) MRT with TR = 750 ms, TE = 50 ms, FoV = 160 mm, and Matrix 512 x 512 was used for this purpose. The MR signal intensities of the cartilage were read out along slices with constant height above the subchondral bone and plotted versus the actual angle to the external magnetic field. The obtained intensity curves were fitted by a model distribution, and the degree of order of the collagen fibers was calculated. For the knee meniscal cartilage, there was an age-dependency of the degree of order and a significant deviation of the volunteer with arthrosis from the normal curve. The results are discussed in view of the arcade model and of a possible use of non-invasive clinical MRT for the detection of early arthrotic changes of cartilage. (orig.)

  7. Frequency of Intracranial Aneurysms Determined by Magnetic Resonance Angiography in Children (Mean Age 16) Having Operative or Endovascular Treatment of Coarctation of the Aorta (Mean Age 3).

    Science.gov (United States)

    Donti, Andrea; Spinardi, Luca; Brighenti, Maurizio; Faccioli, Luca; Leoni, Chiara; Fabi, Marianna; Trossello, Marco P; Gargiulo, Gaetano D; Bonvicini, Marco

    2015-08-15

    Coarctation of the aorta (CofA) has been associated with an increased risk of intracranial aneurysm (IA). This magnetic resonance angiography (MRA) study investigates the prevalence of IAs in 80 children treated in early life for CofA. MRA was performed at mean age of 15.7 ± 7.1 years, and surgical or endovascular treatment for CofA occurred at a mean age of 2.6 ± 4.4 years. No IA was found. In contrast with earlier findings in adult patients with late treatment for CofA, this first systematic study of very early treated patients for CofA failed to confirm the association between CofA and IAs. Our results call the abnormal developmental relation between CofA and IAs into question and suggest that modifiable risk factors like hypertension may be responsible for IA development in patients with CofA with adult diagnosis and treatment. In conclusion, our data suggest that early treatment of CofA can reduce the formation of IAs in children so as to make MRA screening less valuable in this young population.

  8. Dynamic Kine Magnetic Resonance Imaging in Whiplash Patients and in Age- and Sex-Matched Controls

    Directory of Open Access Journals (Sweden)

    Karl-August Lindgren

    2009-01-01

    Full Text Available The multitude of symptoms following a whiplash injury has given rise to much discussion because of the lack of objective radiological findings. The ligaments that stabilize the upper cervical spine can be injured. Dynamic kine magnetic resonance imaging (dMRI may reveal the pathological motion patterns caused by injury to these ligaments. To compare the findings and motion patterns in the upper cervical spine, 25 whiplash trauma patients with longstanding pain, limb symptoms and loss of balance indicating a problem at the level of C0–C2, as well as matched healthy controls were imaged using dMRI. Imaging was performed with an Intera 1.5 T (Philips Healthcare, USA magnet. A physiotherapist performed the bending and rotation of the upper cervical spine for the subjects to ensure that the movements were limited to the C0–C2 level. An oblique coronal T2- and proton density-weighted sequence and a balanced fast field echo axial sequence were used. The movements between C0–C2 and the signal from the alar ligaments were analyzed. Contact of the transverse ligament and the medulla in rotation was seen in two patients. The signal from the alar ligaments was abnormal in 92% of the patients and in 24% of the control subjects (P<0.0001. Abnormal movements at the level of C1–C2 were more common in patients than in controls (56% versus 20%, P=0.028. Whiplash patients with longstanding symptoms had both more abnormal signals from the alar ligaments and more abnormal movements on dMRI at the C0–C2 level than controls.

  9. Age-Associated Reduction of Asymmetry in Human Central Auditory Function: A 1H-Magnetic Resonance Spectroscopy Study

    Directory of Open Access Journals (Sweden)

    Xianming Chen

    2013-01-01

    Full Text Available The aim of this study was to investigate the effects of age on hemispheric asymmetry in the auditory cortex after pure tone stimulation. Ten young and 8 older healthy volunteers took part in this study. Two-dimensional multivoxel 1H-magnetic resonance spectroscopy scans were performed before and after stimulation. The ratios of N-acetylaspartate (NAA, glutamate/glutamine (Glx, and γ-amino butyric acid (GABA to creatine (Cr were determined and compared between the two groups. The distribution of metabolites between the left and right auditory cortex was also determined. Before stimulation, left and right side NAA/Cr and right side GABA/Cr were significantly lower, whereas right side Glx/Cr was significantly higher in the older group compared with the young group. After stimulation, left and right side NAA/Cr and GABA/Cr were significantly lower, whereas left side Glx/Cr was significantly higher in the older group compared with the young group. There was obvious asymmetry in right side Glx/Cr and left side GABA/Cr after stimulation in young group, but not in older group. In summary, there is marked hemispheric asymmetry in auditory cortical metabolites following pure tone stimulation in young, but not older adults. This reduced asymmetry in older adults may at least in part underlie the speech perception difficulties/presbycusis experienced by aging adults.

  10. Age and gender specific normal values of left ventricular mass, volume and function for gradient echo magnetic resonance imaging: a cross sectional study

    Directory of Open Access Journals (Sweden)

    Allansdotter-Johnsson Ase

    2009-01-01

    Full Text Available Abstract Background Knowledge about age-specific normal values for left ventricular mass (LVM, end-diastolic volume (EDV, end-systolic volume (ESV, stroke volume (SV and ejection fraction (EF by cardiac magnetic resonance imaging (CMR is of importance to differentiate between health and disease and to assess the severity of disease. The aims of the study were to determine age and gender specific normal reference values and to explore the normal physiological variation of these parameters from adolescence to late adulthood, in a cross sectional study. Methods Gradient echo CMR was performed at 1.5 T in 96 healthy volunteers (11–81 years, 50 male. Gender-specific analysis of parameters was undertaken in both absolute values and adjusted for body surface area (BSA. Results Age and gender specific normal ranges for LV volumes, mass and function are presented from the second through the eighth decade of life. LVM, ESV and EDV rose during adolescence and declined in adulthood. SV and EF decreased with age. Compared to adult females, adult males had higher BSA-adjusted values of EDV (p = 0.006 and ESV (p Conclusion LV volumes, mass and function vary over a broad age range in healthy individuals. LV volumes and mass both rise in adolescence and decline with age. EF showed a rapid decline in adolescence compared to changes throughout adulthood. These findings demonstrate the need for age and gender specific normal ranges for clinical use.

  11. Interdependencies of aortic arch secondary flow patterns, geometry, and age analysed by 4-dimensional phase contrast magnetic resonance imaging at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Frydrychowicz, Alex [University Hospital Schleswig-Holstein, Clinic for Radiology and Nuclear Medicine, Luebeck (Germany); Berger, Alexander; Russe, Maximilian F.; Bock, Jelena [University Hospital Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Munoz del Rio, Alejandro [University of Wisconsin - Madison, Departments of Radiology and Medical Physics, Madison, WI (United States); Harloff, Andreas [University Hospital Freiburg, Department of Neurology and Clinical Neurophysiology, Freiburg (Germany); Markl, Michael [University Hospital Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Northwestern University, Departments of Radiology and Biomedical Engineering, Chicago, IL (United States)

    2012-05-15

    It was the aim to analyse the impact of age, aortic arch geometry, and size on secondary flow patterns such as helix and vortex flow derived from flow-sensitive magnetic resonance imaging (4D PC-MRI). 62 subjects (age range = 20-80 years) without circumscribed pathologies of the thoracic aorta (ascending aortic (AAo) diameter: 3.2 {+-} 0.6 cm [range 2.2-5.1]) were examined by 4D PC-MRI after IRB-approval and written informed consent. Blood flow visualisation based on streamlines and time-resolved 3D particle traces was performed. Aortic diameter, shape (gothic, crook-shaped, cubic), angle, and age were correlated with existence and extent of secondary flow patterns (helicity, vortices); statistical modelling was performed. Helical flow was the typical pattern in standard crook-shaped aortic arches. With altered shapes and increasing age, helicity was less common. AAo diameter and age had the highest correlation (r = 0.69 and 0.68, respectively) with number of detected vortices. None of the other arch geometric or demographic variables (for all, P {>=} 0.177) improved statistical modelling. Substantially different secondary flow patterns can be observed in the normal thoracic aorta. Age and the AAo diameter were the parameters correlating best with presence and amount of vortices. Findings underline the importance of age- and geometry-matched control groups for haemodynamic studies. (orig.)

  12. Metabolic changes in the anterior and posterior cingulate cortices of the normal aging brain: proton magnetic resonance spectroscopy study at 3 T.

    Science.gov (United States)

    Chiu, Pui-Wai; Mak, Henry Ka-Fung; Yau, Kelvin Kai-Wing; Chan, Queenie; Chang, Raymond Chuen-Chung; Chu, Leung-Wing

    2014-02-01

    Magnetic resonance spectroscopy (MRS) can explore aging at a molecular level. In this study, we investigated the relationships between regional concentrations of metabolites (such as choline, creatine, myo-inositol, and N-acetyl-aspartate) and normal aging in 30 cognitively normal subjects (15 women and 15 men, age range 22-82, mean = 49.9 ± 18.3 years) using quantitative proton magnetic resonance spectroscopy. All MR scans were performed using a 3 T scanner. Point resolved spectroscopy was used as the volume selection method for the region-of-interest and the excitation method for water suppression. Single voxel spectroscopy with short echo time of 39 ms and repetition time of 2,000 ms was employed. Single voxels were placed in the limbic regions, i.e., anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and left and right hippocampi. Cerebrospinal fluid normalization and T1 and T2 correction factors were implemented in the calculation of absolute metabolite concentrations. A standardized T1W 3D volumetric fast field echo and axial T2-weighted fast spin-echo images were also acquired. Our results showed significant positive correlation of choline (r = 0.545, p = 0.002), creatine (r = 0.571, p = 0.001), and N-acetyl-aspartate (r = 0.674, p age. No significant gender effect on metabolite concentrations was found. In aging, increases in choline and creatine might suggest glial proliferation, and an increase in N-acetyl-aspartate might indicate neuronal hypertrophy. Such findings highlight the metabolic changes of ACC and PCC with age, which could be compensatory to an increased energy demand coupled with a lower cerebral blood flow.

  13. Age determination of vessel wall hematoma in spontaneous cervical artery dissection: A multi-sequence 3T Cardiovascular Magnetic resonance study

    Directory of Open Access Journals (Sweden)

    Habs Maximilian

    2011-11-01

    Full Text Available Abstract Background Previously proposed classifications for carotid plaque and cerebral parenchymal hemorrhages are used to estimate the age of hematoma according to its signal intensities on T1w and T2w MR images. Using these classifications, we systematically investigated the value of cardiovascular magnetic resonance (CMR in determining the age of vessel wall hematoma (VWH in patients with spontaneous cervical artery dissection (sCAD. Methods 35 consecutive patients (mean age 43.6 ± 9.8 years with sCAD received a cervical multi-sequence 3T CMR with fat-saturated black-blood T1w-, T2w- and TOF images. Age of sCAD was defined as time between onset of symptoms (stroke, TIA or Horner's syndrome and the CMR scan. VWH were categorized into hyperacute, acute, early subacute, late subacute and chronic based on their signal intensities on T1w- and T2w images. Results The mean age of sCAD was 2.0, 5.8, 15.7 and 58.7 days in patients with acute, early subacute, late subacute and chronic VWH as classified by CMR (p Conclusions Signal intensities of VWH in sCAD vary over time and multi-sequence CMR can help to determine the age of an arterial dissection. Furthermore, findings of this study suggest that the time course of carotid hematomas differs from that of cerebral hematomas.

  14. Anatomy and aging of the amygdala and hippocampus in autism spectrum disorder: an in vivo magnetic resonance imaging study of Asperger syndrome.

    Science.gov (United States)

    Murphy, Clodagh M; Deeley, Q; Daly, E M; Ecker, C; O'Brien, F M; Hallahan, B; Loth, E; Toal, F; Reed, S; Hales, S; Robertson, D M; Craig, M C; Mullins, D; Barker, G J; Lavender, T; Johnston, P; Murphy, K C; Murphy, D G

    2012-02-01

    It has been proposed that people with autism spectrum disorder (ASD) have abnormal morphometry and development of the amygdala and hippocampus (AH). However, previous reports are inconsistent, perhaps because they included people of different ASD diagnoses, ages, and health. We compared, using magnetic resonance imaging, the in vivo anatomy of the AH in 32 healthy individuals with Asperger syndrome (12-47 years) and 32 healthy controls who did not differ significantly in age or IQ. We measured bulk (gray + white matter) volume of the AH using manual tracing (MEASURE). We first compared the volume of AH between individuals with Asperger syndrome and controls and then investigated age-related differences. We compared differences in anatomy before, and after, correcting for whole brain size. There was no significant between group differences in whole brain volume. However, individuals with Asperger syndrome had a significantly larger raw bulk volume of total (PAsperger syndrome, had a significant age-related increase in volume (r = 0.486, PAsperger syndrome have significant differences from controls in bulk volume and aging of the amygdala.

  15. Assessment of age-related morphometric changes of subcortical structures in healthy people using ultra-high field 7 tesla magnetic resonance imaging

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    Xueyuan Wang

    2016-09-01

    Full Text Available Objective: To assess the age-related morphometric changes of subcortical structures in healthy people.Material and Methods: Ultra-high field 7 tesla magnetic resonance imaging in humans was used to visualize the subcortical structures of healthy young, middle-aged, and elderly participants. Using the magnetization-prepared two rapid acquisition gradient echoes sequence, we assessed the visibility of the margins of the thalamus and white matter in the thalamus, as well as the anterior commissure (AC and posterior commissure (PC length, the maximal height of the thalamus, the half width of third ventricle, and the distance between the AC and the center of the mammillothalamic tract at the level of the AC-PC plane. All quantitative data were statistically evaluated.Results: The AC-PC length did not differ significantly among the three groups. The maximal height of the thalamus decreased with age (rs(53=-0.719, p<0.001. The half width of the third ventricle (rs(53=0.705, p<0.001 and the distance between the AC and the center of the mammillothalamic tract (MTT (rs(53=0.485, p<0.001 increased with age. The distance between the AC and the center of the MTT of the young and the elderly participants differed significantly (p=0.007.Conclusion: The AC-PC length is not a good candidate for proportional correction during atlas-to-patient registration. The maximal height of the thalamus and the half width of the third ventricle correlated strongly with age, and the MTT position in relation to the AC shifted posteriorly as age increased. These age-related morphometric changes of subcortical structures should be considered in targeting for functional neurosurgery.

  16. Size of the intracranial optic nerve and optic tract in neonates at term-equivalent age at magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Jun; Mori, Kouichi [Tsuchiura Kyodo General Hospital, Department of Radiology, Tsuchiura, Ibaraki (Japan); Imamura, Masatoshi [Tsuchiura Kyodo General Hospital, Department of Neonatology, Tsuchiura, Ibaraki (Japan); Mizushima, Yukiko [Tsuchiura Kyodo General Hospital, Department of Ophthalmology, Tsuchiura, Ibaraki (Japan); Tateishi, Ukihide [Tokyo Medical and Dental University, Departments of Diagnostic Radiology and Nuclear Medicine, Tokyo (Japan)

    2016-04-15

    The expected MRI-based dimensions of the intracranial optic nerve and optic tract in neonates are unknown. To evaluate the sizes of the intracranial optic nerve and optic tract in neonates at term-equivalent age using MRI. We retrospectively analyzed brain MRI examinations in 62 infants (28 boys) without intracranial abnormalities. The images were obtained in infants at term-equivalent age with a 1.5-tesla MRI scanner. We measured the widths and heights of the intracranial optic nerve and optic tract and calculated the cross-sectional areas using the formula for an ellipse. The means ± standard deviation of the width, height and cross-sectional area of the intracranial optic nerve were 2.7 ± 0.2 mm, 1.7 ± 0.2 mm and 3.5 ± 0.5 mm{sup 2}, respectively. The width, height and cross-sectional area of the optic tract were 1.5 ± 0.1 mm, 1.6 ± 0.1 mm and 2.0 ± 0.2 mm{sup 2}, respectively. Using univariate and multivariate analyses, we found that postmenstrual age showed independent intermediate positive correlations with the width (r = 0.48, P < 0.01) and cross-sectional area (r = 0.40, P < 0.01) of the intracranial optic nerve. The lower bounds of the 95% prediction intervals for the width and cross-sectional area of the intracranial optic nerve were 0.07 x (postmenstrual age in weeks) - 0.46 mm, and 0.17 x (postmenstrual age in weeks) - 4.0 mm{sup 2}, respectively. We identified the sizes of the intracranial optic nerve and optic tract in neonates at term-equivalent age. The postmenstrual age at MRI independently positively correlated with the sizes. (orig.)

  17. Prevalence of Age-Related Changes in Ovine Lumbar Intervertebral Discs during Computed Tomography and Magnetic Resonance Imaging.

    Science.gov (United States)

    Nisolle, Jean-François; Bihin, Benoît; Kirschvink, Nathalie; Neveu, Fabienne; Clegg, Peter; Dugdale, Alexandra; Wang, Xiaoqing; Vandeweerd, Jean-Michel

    2016-01-01

    Ovine models are used to study intervertebral disc (IVD) degeneration. The objective of the current study was to assess the naturally occurring age-related changes of the IVD that can be diagnosed by CT and MRI in the lumbar spine of sheep. We used CT and T2-weighted MR images to score the IVD (L6S1 to L1L2) in 41 sheep (age, 6 mo to 11 y) that were euthanized for reasons not related to musculoskeletal disease. T2 mapping and measurement of T2 time of L6S1 to L2L3 were performed in 22 of the sheep. Degenerative changes manifested as early as 2 y of age and occurred at every IVD level. Discs were more severely damaged in older sheep. The age effect of the L6S1 IVD was larger than the average age effect for the other IVD. The current study provides evidence that lesions similar to those encountered in humans can be identified by CT and MRI in lumbar spine of sheep. Ideally, research animals should be assessed at the initiation of preclinical trials to determine the extent of prevalent degenerative changes. The ovine lumbosacral disc seems particularly prone to degeneration and might be a favorable anatomic site for studying IVD degeneration.

  18. Are the determinants of vertebral endplate changes and severe disc degeneration in the lumbar spine the same? A magnetic resonance imaging study in middle-aged male workers

    Directory of Open Access Journals (Sweden)

    Korpelainen Raija

    2008-04-01

    Full Text Available Abstract Background Modic changes are bone marrow lesions visible in magnetic resonance imaging (MRI, and they are assumed to be associated with symptomatic intervertebral disc disease, especially changes located at L5-S1. Only limited information exists about the determinants of Modic changes. The objective of this study was to evaluate the determinants of vertebral endplate (Modic changes, and whether they are similar for Modic changes and severe disc degeneration focusing on L5-S1 level. Methods 228 middle-aged male workers (159 train engineers and 69 sedentary factory workers from northern Finland underwent sagittal T1- and T2-weighted MRI. Modic changes and disc degeneration were analyzed from the scans. The participants responded to a questionnaire including items of occupational history and lifestyle factors. Logistic regression analysis was used to evaluate the associations between selected determinants (age, lifetime exercise, weight-related factors, fat percentage, smoking, alcohol use, lifetime whole-body vibration and Modic type I and II changes, and severe disc degeneration (= grade V on Pfirrmann's classification. Results The prevalences of the Modic changes and severe disc degeneration were similar in the occupational groups. Age was significantly associated with all degenerative changes. In the age-adjusted analyses, only weight-related determinants (BMI, waist circumference were associated with type II changes. Exposure to whole-body vibration, besides age, was the only significant determinant for severe disc degeneration. In the multivariate model, BMI was associated with type II changes at L5-S1 (OR 2.75 per one SD = 3 unit increment in BMI, and vibration exposure with severe disc degeneration at L5-S1 (OR 1.08 per one SD = 11-year increment in vibration exposure. Conclusion Besides age, weight-related factors seem important in the pathogenesis of Modic changes, whereas whole-body vibration was the only significant determinant

  19. Age-related white matter degradation rule of normal human brain: the evidence from diffusion tensor magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiang; Li Baoqing; Shan Baoci

    2014-01-01

    Background Diffusion tensor imaging can evaluate white matter function in human brain.Fractional anisotropy is the most important parameter.This study aimed to find regional reduction of fractional anisotropy (FA) with aging in the whole brain and the changing rules of anisotropy with aging.Methods Fifty volunteers from 20 to 75 years old were divided into five consecutive age groups; a young group and four senior groups.FA values were calculated with diffusion tensor imaging (DTI) studio software.The difference of FA between the young group and the four senior groups were analyzed by analysis of voxel-level height threshold in Statistic Parametric Mapping (SPM),and the regions with decreased FA were obtained.The FA values of these regions were then extracted using an in-house developed program,and a multiple linear regression model was built to assess the influence of age and sex on the FA values of these regions.Results Eight regions,including frontal lobe,postcentral gyrus,optic radiation,hippocampus,cerebella hemisphere,corona radiate,corpus callosum and internal capsule,were found to have decreased FA.There was a strong negative correlation between age and the FA in the frontal lobe,postcentral gyrus,optic radiation,hippocampus,and cerebella hemisphere,while a weaker negative correlation in the corona radiate,corpus callosum,and internal capsule was found.The FA reduction in the frontal lobe,postcentral gyrus,optic radiation,hippocampus and cerebella hemisphere were found earlier than in the corona radiate,corpus callosum and internal capsule.There was no correlation between sex and FA in these regions.Conclusions The FA in the subcortical white matter area reduces earlier than that in deep white matter.The areas with decreased FA continuously enlarge with aqing.The FAs in these regions have a strong negative correlation with age.

  20. Decrease in the cortical intensity on T{sub 2}-weighted magnetic resonance imaging with aging in normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Imon, Yukari; Murata, Yoshio; Kajima, Toshio; Nakamura, Shigenobu [Hiroshima Univ. (Japan). School of Medicine; Yamaguchi, Shinya

    1997-03-01

    We reported previously that Low T{sub 2} intensity areas (LIAs) are more common in patients with central nervous system (CNS) diseases than in those with no such diseases, and that the occurrence of LIAs increases with aging. To determine a relationship between the intensity changes and aging, we investigated the intensity of the cerebral cortex in 26 normal Japanese individuals. Measurements of brain MRIs were performed with a Signa Advantage apparatus at 1.5 tesla. T{sub 2}-weighted images were obtained using the spin-echo pulse sequences. On our laboratory console, we measured signal intensities in the regions of interest in the prefrontal, motor, sensory, parietal, temporal, or occipital cortex, and in the frontal white matter. To remove the effect of the system gain settings on signal intensity, that of cerebrospinal fluid was used as reference according to the method of Pujol et al. The average intensity in the temporal and prefrontal cortices was the highest, followed in order by the parietal, sensory, motor, and occipital cortices. The intensity in the temporal and parietal cortices decreased significantly with aging, and that in the motor and sensory cortices had a tendency to decrease with aging. The intensity in the motor and sensory cortices of the elderly subjects and that in the occipital cortex throughout all ages were lower than that in the prefrontal white matter, which would result in the appearance of LIAs. The average intensity of each cerebral cortex was inversely related to the non-heme iron content previously reported. It is likely that the difference in intensity among the cortices reflects variations of the non-heme iron content, and that the change in intensity with aging could be due to the increase in such cortical senile changes as that of microglia, astroglia, and senile plaques, which contain iron or iron-related proteins. The temporal cortex is most susceptible to senile changes. (K.H.)

  1. Age-specific changes in left ventricular diastolic function: A velocity-encoded magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Ashrafpoor, Golmehr [Sorbonne Universites, UPMC Univ Paris 06, UMR 7371, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); INSERM, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); CNRS, UMR 7371, Laboratoire d' Imagerie Biomedicale, Paris (France); Universite Paris Descartes, Cardiovascular Imaging Department, European Hospital Georges Pompidou, Paris (France); Bollache, Emilie; Cesare, Alain de; Giron, Alain; Defrance, Carine; Kachenoura, Nadjia [Sorbonne Universites, UPMC Univ Paris 06, UMR 7371, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); INSERM, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); CNRS, UMR 7371, Laboratoire d' Imagerie Biomedicale, Paris (France); Redheuil, Alban [Sorbonne Universites, UPMC Univ Paris 06, UMR 7371, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); INSERM, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); CNRS, UMR 7371, Laboratoire d' Imagerie Biomedicale, Paris (France); Hopital Pitie-Salpetriere, Department of Cardiovascular Radiology, Institut de Cardiologie, Paris (France); ICAN, Imaging Core Lab, Paris (France); Azarine, Arshid [INSERM, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); Universite Paris Descartes, Cardiovascular Imaging Department, European Hospital Georges Pompidou, Paris (France); Perdrix, Ludivine; Ladouceur, Magalie [European Hospital Georges Pompidou, Cardiology Department, Paris (France); Diebold, Benoit [Sorbonne Universites, UPMC Univ Paris 06, UMR 7371, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); INSERM, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); CNRS, UMR 7371, Laboratoire d' Imagerie Biomedicale, Paris (France); European Hospital Georges Pompidou, Cardiology Department, Paris (France); Mousseaux, Elie [Sorbonne Universites, UPMC Univ Paris 06, UMR 7371, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); INSERM, UMR S 1146, Laboratoire d' Imagerie Biomedicale, Paris (France); CNRS, UMR 7371, Laboratoire d' Imagerie Biomedicale, Paris (France); Universite Paris Descartes, Cardiovascular Imaging Department, European Hospital Georges Pompidou, Paris (France); European Hospital Georges Pompidou, Cardiology Department, Paris (France)

    2015-04-01

    Our objectives were to assess the ability of phasecontrast MRI (PC-MRI) to detect sub-clinical age-related variations of left ventricular (LV) diastolic parameters and thus to provide age-related reference ranges currently available for echocardiography but not for MRI-PC, and to identify independent associates of such variations. We studied 100 healthy volunteers (age = 42 ± 15years, 50 females) who had MRI with simultaneous blood pressure measurements. LV mass and volumes were assessed. Semiautomated analysis of PC-MRI data provided: 1) early transmitral (Ef) and atrial (Af) peak filling flow-rates (ml/s) and filling volume (FV), 2) deceleration time (DT), isovolumic relaxation time (IVRT), and 3) early myocardial longitudinal (E') peak velocity. MRI-PC diastolic parameters were reproducible as reflected by low coefficients of variations (ranged between 0.31 to 6.26 %). Peak myocardial velocity E' (r = -0.63, p < 0.0001) and flow-rate parameters were strongly and independently associated to age (Ef/Af:r = -0.63, DT:r = 0.46, IVRT:r = 0.44, Ef/FV:r = -0.55, Af/FV:r = 0.56, p < 0.0001). Furthermore, LV relaxation parameters (E', DT, IVRT), were independently associated to LV remodelling (LV mass/end-diastolic volume) and myocardial wall thickness (p < 0.01). PC-MRI age-related reference ranges of diastolic parameters are provided. Such parameters might be useful for a fast, reproducible and reliable characterization of diastolic function in patients referred for clinical MRI exam. (orig.)

  2. Using functional Magnetic Resonance Imaging to differentiate between Healthy Aging subjects, Mild Cognitive Impairment, and Alzheimer’s Patients

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Oghabian

    2010-01-01

    Full Text Available

    Back ground: Alzheimer's disease is the most common form of dementia which is still difficult to be differentiated from other types of brain disorders. Moreover, Mild Cognitive Impairment refers to the presence of cognitive impairments that is not severe enough to meet the criteria of dementia, and its diagnosis in early stages is so critical. There is currently no distinct method available for diagnosing Alzheimer's or Mild Cognitive Impairment, and their diagnosis needs a combination of different methods and assessments.

    Methods: Our goal in this study was to evaluate the effectiveness of fMRI imaging in differentiating between Alzheimer's, Mild Cognitive Impairment (MCI and Healthy Aging. To prove fMRI's ability, we compared resting-state brain activation patterns between these three groups of subjects using Independent Component Algorithm (ICA. We examined 40 age- and sex-matched subjects, 15 elderly, 11 MCI and 14 Alzheimer's subjects.

    Results: The results show that during a certain resting-state session, healthy aging brain benefits from larger area and greater intensity of activation (compared with MCI and Alzheimer's group in Posterior Cingulate Cortex (PCC region of the brain, as part of Default Mode Network.

    Conclusion: This difference in activation pattern can be used as a diagnostic criterion in using fMRI for differentiating between Alzheimer's disease (AD, MCI and Healthy Aging.


    Keywords: fMRI, Default Mode Network, Alzheimer's, Mild Cognitive Impairment, Resting-State

  3. Event-related functional magnetic resonance imaging changes during relational retrieval in normal aging and amnestic mild cognitive impairment.

    Science.gov (United States)

    Giovanello, Kelly S; De Brigard, Felipe; Hennessey Ford, Jaclyn; Kaufer, Daniel I; Burke, James R; Browndyke, Jeffrey N; Welsh-Bohmer, Kathleen A

    2012-09-01

    The earliest cognitive deficits observed in amnestic mild cognitive impairment (aMCI) appear to center on memory tasks that require relational memory (RM), the ability to link or integrate unrelated pieces of information. RM impairments in aMCI likely reflect neural changes in the medial temporal lobe (MTL) and posterior parietal cortex (PPC). We tested the hypothesis that individuals with aMCI, as compared to cognitively normal (CN) controls, would recruit neural regions outside of the MTL and PPC to support relational memory. To this end, we directly compared the neural underpinnings of successful relational retrieval in aMCI and CN groups, using event-related functional magnetic resonance imaging (fMRI), holding constant the stimuli and encoding task. The fMRI data showed that the CN, compared to the aMCI, group activated left precuneus, left angular gyrus, right posterior cingulate, and right parahippocampal cortex during relational retrieval, while the aMCI group, relative to the CN group, activated superior temporal gyrus and supramarginal gyrus for this comparison. Such findings indicate an early shift in the functional neural architecture of relational retrieval in aMCI, and may prove useful in future studies aimed at capitalizing on functionally intact neural regions as targets for treatment and slowing of the disease course. (JINS, 2012, 18, 1-12).

  4. Meta-analysis of functional magnetic resonance imaging studies of inhibition and attention in attention-deficit/hyperactivity disorder: exploring task-specific, stimulant medication, and age effects.

    Science.gov (United States)

    Hart, Heledd; Radua, Joaquim; Nakao, Tomohiro; Mataix-Cols, David; Rubia, Katya

    2013-02-01

    CONTEXT Functional magnetic resonance imaging studies in attention-deficit/hyperactivity disorder (ADHD) revealed fronto-striato-parietal dysfunctions during tasks of inhibition and attention. However, it is unclear whether task-dissociated dysfunctions exist and to what extent they may be influenced by age and by long-term stimulant medication use. OBJECTIVE To conduct a meta-analysis of functional magnetic resonance imaging studies in ADHD during inhibition and attention tasks, exploring age and long-term stimulant medication use effects. DATA SOURCES PubMed, ScienceDirect, Web of Knowledge, Google Scholar, and Scopus databases were searched up to May 2012 for meta-analyses. Meta-regression methods explored age and long-term stimulant medication use effects. STUDY SELECTION Twenty-one data sets were included for inhibition (287 patients with ADHD and 320 control subjects), and 13 data sets were included for attention (171 patients with ADHD and 178 control subjects). DATA EXTRACTION Peak coordinates of clusters of significant group differences, as well as demographic, clinical, and methodological variables, were extracted for each study or were obtained from the authors. DATA SYNTHESIS Patients with ADHD relative to controls showed reduced activation for inhibition in the right inferior frontal cortex, supplementary motor area, and anterior cingulate cortex, as well as striato-thalamic areas, and showed reduced activation for attention in the right dorsolateral prefrontal cortex, posterior basal ganglia, and thalamic and parietal regions. Furthermore, the meta-regression analysis for the attention domain showed that long-term stimulant medication use was associated with more similar right caudate activation relative to controls. Age effects could be analyzed only for the inhibition meta-analysis, showing that the supplementary motor area and basal ganglia were underactivated solely in children with ADHD relative to controls, while the inferior frontal cortex and

  5. High-field magnetic resonance imaging of the developing human brain from the 10th to the 16th week of gestational Age.

    Science.gov (United States)

    Sbarbati, A; Marzola, P; Simonati, A; Nicolato, E; Osculati, F

    1998-01-01

    In the present work, high-field magnetic resonance imaging (HF-MRI) was applied to study the developing human brain paying particular attention to the structures of interest in pathology of malformation. The aim of the work was to evaluate the possible application of HF-MRI to the analysis of brain development in the absence of some limits of conventional histological technique. Seven formalin-fixed human fetuses of 50, 65, 70, 85, 110, 116 and 125 mm crown/ rump length (corresponding to a gestational age ranging from 10 to 16 weeks) were examined in an imager-spectrometer equipped with a 4. 7-tesla horizontal magnet with a 33-cm bore. In the brain of all the fetuses the telencephalic, mesencephalic and rhombencephalic vesicles were recognizable and an easy quantitative evaluation of the brain curvatures in the absence of distortion due to dissection was possible. Comparing fetuses at different gestational ages, the spatial modification of the different vesicles was evident. In fetuses at 16 weeks of gestational age, stratified compartments of the telencephalic wall were evident. The germinal zone and the cortical plate were visible: the germinal layer was identifiable as a hypointensity in the periventricular area. The subplate zone and the intermediate zone emitted a strong intensity signal. Our study demonstrates that HF-MRI can contribute to the study of the complex developmental events in the human brain from the 10th to 16th week of gestational age in a submillimetric scale of resolution. This technique can provide information about the morphology of the encephalic vesicles and their relations with the bone cavity that cannot be obtained with conventional methods and may be a useful adjunct to histological techniques.

  6. Routine Magnetic Resonance Imaging at Term-Equivalent Age Detects Brain Injury in 25% of a Contemporary Cohort of Very Preterm Infants

    Science.gov (United States)

    Djurdjevic, Tanja; Griesmaier, Elke; Biermayr, Marlene; Gizewski, Elke Ruth; Kiechl-Kohlendorfer, Ursula

    2017-01-01

    Introduction In recent years, significant investigation has been undertaken by means of magnetic resonance imaging (MRI) in an attempt to identify preterm infants at risk for adverse outcome. The primary objective is to provide a comprehensive characterization of cerebral injury detected by conventional MRI at term-equivalent age in an unselected, consecutive, contemporary cohort of preterm infants born <32 gestational weeks. Secondly, this study aims to identify risk factors for the different injury types in this population. Methods Data for all preterm infants born <32 gestational weeks and admitted to Innsbruck Medical University Hospital were prospectively collected (October 2010 to December 2015). Cerebral MRI was evaluated retrospectively using a validated scoring system that incorporates intraventricular haemorrhage (IVH), white matter disease (WMD) and cerebellar haemorrhage (CBH). Results 300 infants were included in the study. MRI showed 24.7% of all infants to have some form of brain injury. The most common injury type was IVH (16.0%). WMD and CBH were seen in 10.0% and 8.0%. The prevalence of common neonatal risk factors was greater within the group of infants with CBH. In particular indicators for respiratory disease were observed more often: longer ventilation duration, more frequent need for supplemental oxygen at day 28, higher rates of hydrocortisone treatment. Catecholamine treatment was the only neonatal risk factor that was overrepresented in infants with WMD Discussion Cerebral MRI at term-equivalent age, as addition to cranial ultrasound, detected brain injury in 25% of preterm survivors. The diagnosis of IVH was already made by neonatal ultrasound in most cases. In contrast, only a minority of the CBH and none of the non-cystic WMD have been detected prior to MRI. Decreasing gestational age and neonatal complications involved with immaturity have been identified as risk factors for CBH, whereas WMD was found in relatively mature infants with

  7. A prospective study of magnetic resonance imaging patterns of central nervous system infections in pediatric age group and young adults and their clinico-biochemical correlation

    Directory of Open Access Journals (Sweden)

    Kamini Gupta

    2016-01-01

    Full Text Available Background: Infections of the central nervous system (CNS are common and routinely encountered. Our aim was to evaluate the neuroimaging features of the various infections of the CNS so as to differentiate them from tumoral, vascular, and other entities that warrant a different line of therapy. Aims: Our aim was to analyze the biochemical and magnetic resonance imaging (MRI features in CNS infections. Settings and Design: This was a longitudinal, prospective study over a period of 1½ years. Subjects and Methods: We studied cerebrospinal fluid (CSF findings and MRI patterns in 27 patients of 0–20 years age group with clinical features of CNS infections. MRI was performed on MAGNETOM Avanto 18 Channel 1.5 Tesla MR machine by Siemens India Ltd. The MRI protocol consisted of diffusion-weighted and apparent diffusion coefficient imaging, turbo spin echo T2-weighted, spin echo T1-weighted, fluid-attenuated inversion recovery (FLAIR, and gradient-echo in axial, FLAIR in coronal, and T2-weighted in sagittal plane. Contrast-enhanced T1-weighted sequence and MR spectroscopy were done whenever indicated. Results and Conclusions: We found that most of the children belong to 1–10 years age group. Fungal infections were uncommon, mean CSF adenosine deaminase values specific for tuberculosis and mean CSF glucose-lowered in pyogenic. Hemorrhagic involvement of thalamus with/without basal ganglia and brainstem involvement may indicate Japanese encephalitis or dengue encephalitis. Diffusion restriction or hemorrhage in not expected in the brainstem afflicted lesions of rabies. Congenital cytomegalovirus can cause cortical malformations. T1 hyperintensities with diffusion restriction may represent viral encephalitis. Lesions of acute disseminated encephalomyelitis (ADEM may mimic viral encephalitis. Leptomeningeal enhancement is predominant in pyogenic meningitis. Basilar meningitis in the presence of tuberculomas is highly sensitive and specific for

  8. Relationship between Proton Magnetic Resonance Spectroscopy of Frontoinsular Gray Matter and Neurodevelopmental Outcomes in Very Low Birth Weight Children at the Age of 4.

    Directory of Open Access Journals (Sweden)

    Wojciech Durlak

    Full Text Available Very low birth weight is associated with long term neurodevelopmental complications. Macroscopic brain abnormalities in prematurity survivors have been investigated in several studies. However, there is limited data regarding local cerebral metabolic status and neurodevelopmental outcomes. The purpose of this study was to characterize the relationship between proton magnetic resonance spectra in basal ganglia, frontal white matter and frontoinsular gray matter, neurodevelopmental outcomes assessed with the Leiter scale and the Developmental Test of Visual Perception and selected socioeconomic variables in a cohort of very low birth weight children at the age of four. Children were divided in three groups based on the severity of neurodevelopmental impairment. There were no differences in spectroscopy in basal ganglia and frontal white matter between the groups. Lower concentrations of N-acetylaspartate (NAA, choline (Cho and myoinositol (mI were observed in the frontoinsular cortex of the left hemisphere in children with neurodevelopmental impairment compared to children with normal neurodevelopmental outcomes. Higher parental education, daycare attendance and breastfeeding after birth were associated with more favorable neurodevelopmental prognosis, whereas rural residence was more prevalent in children with moderate and severe impairment. Our study demonstrates the role of long term neurometabolic disruption in the left frontoinsular cortex and selected socioeconomic variables in determination of neurodevelopmental prognosis in prematurity survivors.

  9. The Influence of Magnetic Resonance Imaging Findings of Degenerative Disease on Dual-Energy X-ray Absorptiometry Measurements in Middle-Aged Men

    Energy Technology Data Exchange (ETDEWEB)

    Donescu, O.S.; Battie, M.C.; Videman, T. [Faculty of Rehabilitation Medicine and Dept. of Physical Therapy, Univ. of Alberta (Canada)

    2007-02-15

    Purpose: To examine degenerative features based on magnetic resonance imaging (MRI) measurements at the lumbar spine in relation to dual-energy X-ray absorptiometry (DXA), and to investigate whether bone mineral density (BMD) is reflected in the substitution of bone trabecular structure by fat at the vertebral body level indicated by MRI T1 relaxation time, endplate concavity, and hypertrophic (osteophytes and endplate sclerosis) MRI findings. Material and Methods: The sample for this cross-sectional study was composed of 102 subjects, 35-70 years old, from a population-based cohort. Data collection included DXA in the anterior-posterior projection at the L1-L4 vertebrae and right femoral neck, and MRI of the lumbar spine in the midsagittal plane. Results: Age, vertebral signal intensity, osteophytes, and endplate concavity collectively explained 20% of the variance in spine BMD. Conclusion: The study findings suggest that degenerative findings based on MRI measurements at the lumbar spine have an influence on bone assessment using DXA. Therefore, an overall bone assessment such as DXA might not offer an accurate measure of BMD.

  10. Effects of electrospun chitosan wrapping for dry-ageing of beef, as studied by microbiological, physicochemical and low-field nuclear magnetic resonance analysis

    DEFF Research Database (Denmark)

    Guðjónsdóttir, María; Gacutan, Manuel D.; Mendes, Ana Carina Loureiro

    2015-01-01

    The effects of using electrospun chitosan fibres as a wrapping material for dry-ageing beef was studied and compared to traditional dry-ageing and wet-ageing of beef for up to 21 days. The chitosan treatment showed improved results in terms of yield, reduction of microbial counts, yeasts and moulds......, and lighter appearance compared to traditional dry-ageing. Weight and trimming losses were minimal in the wet-ageing beef. However, significant growth of lactic acid bacteria was observed in this group. Transverse relaxation times indicated a lower degree of muscle denaturation during ageing in the chitosan...... chitosan fibre mats have potential as a wrapping material for improved quality during dry-ageing of beef....

  11. Photothermal resonance

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates to an ap......The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates...... to an apparatus for detecting photo-thermal absorbance of a sample....

  12. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  13. Functional Magnetic Resonance Imaging Study of Piaget's Conservation-of-Number Task in Preschool and School-Age Children: A Neo-Piagetian Approach

    Science.gov (United States)

    Houde, Olivier; Pineau, Arlette; Leroux, Gaelle; Poirel, Nicolas; Perchey, Guy; Lanoe, Celine; Lubin, Amelie; Turbelin, Marie-Renee; Rossi, Sandrine; Simon, Gregory; Delcroix, Nicolas; Lamberton, Franck; Vigneau, Mathieu; Wisniewski, Gabriel; Vicet, Jean-Rene; Mazoyer, Bernard

    2011-01-01

    Jean Piaget's theory is a central reference point in the study of logico-mathematical development in children. One of the most famous Piagetian tasks is number conservation. Failures and successes in this task reveal two fundamental stages in children's thinking and judgment, shifting at approximately 7 years of age from visuospatial intuition to…

  14. Evaluation of the flow of cerebrospinal fluid as well as gender and age characteristics in patients with communicating hydrocephalus, using phase-contrast magnetic resonance imaging.

    Science.gov (United States)

    Bogomyakova, Olga; Stankevich, Yu; Mesropyan, N; Shaybman, L; Tulupov, A

    2016-12-01

    To determine the difference in the velocity parameters of cerebrospinal fluid flow in patients with varying severity of communicating hydrocephalus compared to a group of healthy volunteers without hydrodynamic disorders. The study involved 35 subjects with communicating hydrocephalus (25 subjects with Evans index of 0.31; 10 subject with Evans index of 0.46) and 62 healthy volunteers. The mean, volume, and peak flow velocities were determined at the different intracranial levels. Also were made an assessment of gender and age differences. Analysis of the differences between the mean values showed the progressive inhibition of cerebrospinal fluid outflow from the cranial cavity [in moderate communicating hydrocephalus-at 1.5 times (p hydrocephalus at 2-2.5 times (p < 0.01)], depending on the severity of enlargement of the ventricular system and, most likely, related to inhibition of its reabsorption. These changes may explain the clinical symptoms of subjects and serve as diagnostic criteria. Also it was revealed a significant influence of the factor of age on speed characteristics of the cerebrospinal fluid flow (F = 5.3303, p = 0.0003, for mean velocity).

  15. Oedema in the Lumbar Subcutaneous Fat, on Routine Magnetic Resonance Imaging, of Patients with No History of Cardiac, Renal or Hepatic Disease, Is Significantly Associated with Obesity and Age

    Directory of Open Access Journals (Sweden)

    WM West

    2015-05-01

    Full Text Available Objectives: To investigate the association between oedema in the subcutaneous fat of the lumbar region during routine magnetic resonance imaging (MRI and patients’ age, gender and body mass index (BMI. Methods: One hundred and forty-nine consecutive examinations of 95 females and 54 males, 18 years and older, scanned at 1.5T between October 1, 2010, and December 31, 2010, were reviewed. Presence and extent of oedema were determined. Oedema was sized on the anatomical segments. Data were analysed using tests for means, odd’s ratio (OR, Chi-squared test, McNemar’s test, linear and backward stepwise multiple regression and analysis of variance (ANOVA. Results: Patients with oedema had significantly higher BMI (30.3 kg/m2 vs 24.9 kg/m2, p < 0.001, and were older (49.9 years vs 43.9 years, p = 0.01 than those without oedema. The OR for oedema in obese vs non-obese patients was 8.6. The Chi-squared and McNemar tests were significant, p = 0 and p < 0.001, respectively. Body mass index and age predicted oedema on backward stepwise regression and, on ANOVA, at 23.6% and 4.7%, respectively. Males were marginally less likely to have oedema (p = 0.056 and had marginally less oedema (p = 0.056 than females. Conclusion: Body mass index and age, but not gender, predict oedema. Body mass index predicts oedema five times as much as age.

  16. Multiquark resonances

    Science.gov (United States)

    Esposito, A.; Pilloni, A.; Polosa, A. D.

    2017-01-01

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties have been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.

  17. Multiquark Resonances

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.

  18. Resonating Statements

    DEFF Research Database (Denmark)

    Hjelholt, Morten; Jensen, Tina Blegind

    2015-01-01

    IT projects are often complex arrangements of technological components, social actions, and organizational transformation that are difficult to manage in practice. This paper takes an analytical discourse perspective to explore the process of legitimizing IT projects. We introduce the concept...... of resonating statements to highlight how central actors navigate in various discourses over time. Particularly, the statements and actions of an IT project manager are portrayed to show how individuals can legitimize actions by connecting statements to historically produced discourses. The case study...... of an IT project in a Danish local government spans a two-year time period and demonstrates a double-loop legitimization process. First, resonating statements are produced to localize a national IT initiative to support the specificity of a local government discourse. Second, the resonating statements are used...

  19. Baryon Resonances

    CERN Document Server

    Oset, E; Sun, Bao Xi; Vacas, M J Vicente; Ramos, A; Gonzalez, P; Vijande, J; Torres, A Martinez; Khemchandani, K

    2009-01-01

    In this talk I show recent results on how many excited baryon resonances appear as systems of one meson and one baryon, or two mesons and one baryon, with the mesons being either pseudoscalar or vectors. Connection with experiment is made including a discussion on old predictions and recent results for the photoproduction of the $\\Lambda(1405)$ resonance, as well as the prediction of one $1/2^+$ baryon state around 1920 MeV which might have been seen in the $\\gamma p \\to K^+ \\Lambda$ reaction.

  20. Baryon Resonances

    Energy Technology Data Exchange (ETDEWEB)

    Oset, E. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Sarkar, S. [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700064 (India); Sun Baoxi [Institute of Theoretical Physics, College of Applied Sciences, Beijing University of Technology, Beijing 100124 (China); Vicente Vacas, M.J. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Ramos, A. [Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, 08028 Barcelona (Spain); Gonzalez, P. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Vijande, J. [Departamento de Fisica Atomica Molecular y Nuclear and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Martinez Torres, A. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptdo. 22085, 46071 Valencia (Spain); Khemchandani, K. [Centro de Fisica Computacional, Departamento de Fisica, Universidade de Coimbra, P-3004-516 Coimbra (Portugal)

    2010-04-01

    In this talk I show recent results on how many excited baryon resonances appear as systems of one meson and one baryon, or two mesons and one baryon, with the mesons being either pseudoscalar or vectors. Connection with experiment is made including a discussion on old predictions and recent results for the photoproduction of the {lambda}(1405) resonance, as well as the prediction of one 1/2{sup +} baryon state around 1920 MeV which might have been seen in the {gamma}p{yields}K{sup +}{lambda} reaction.

  1. Neuroaesthetic Resonance

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    sessions are achieved via adaptive action-analyzed activities. These interactive virtual environments are designed to empower patients’ creative and/or playful expressions via digital feedback stimuli. Unconscious self- pushing of limits result from innate distractive mechanisms offered by the alternative...... the unencumbered motion-to-computer-generated activities - ‘Music Making’, ‘Painting’, ‘Robotic’ and ‘Video Game’ control. A focus of this position paper is to highlight how Aesthetic Resonance, in this context, relates to the growing body of research on Neuroaesthetics to evolve Neuroaesthetic Resonance....

  2. Autostereogram resonators

    Science.gov (United States)

    Leavey, Sean; Rae, Katherine; Murray, Adam; Courtial, Johannes

    2012-09-01

    Autostereograms, or "Magic Eye" pictures, are repeating patterns designed to give the illusion of depth. Here we discuss optical resonators that create light patterns which, when viewed from a suitable position by a monocular observer, are autostereograms of the three-dimensional shape of one of the mirror surfaces.

  3. Experiments with Helmholtz Resonators.

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    1996-01-01

    Presents experiments that use Helmholtz resonators and have been designed for a sophomore-level course in oscillations and waves. Discusses the theory of the Helmholtz resonator and resonance curves. (JRH)

  4. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  5. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  6. Resonance and Neck Length for a Spherical Resonator

    Directory of Open Access Journals (Sweden)

    Emily Corning

    2011-06-01

    Full Text Available The relationship between the neck length of a spherical resonator and its period of fundamental resonance was investigated. This was done by measuring the frequency of fundamental resonance of the resonator at 6 different neck lengths. It was found that its resonance resembled Helmholtz resonance but was not that of ideal Helmholtz resonance.

  7. Integral resonator gyroscope

    Science.gov (United States)

    Shcheglov, Kirill V. (Inventor); Challoner, A. Dorian (Inventor); Hayworth, Ken J. (Inventor); Wiberg, Dean V. (Inventor); Yee, Karl Y. (Inventor)

    2008-01-01

    The present invention discloses an inertial sensor having an integral resonator. A typical sensor comprises a planar mechanical resonator for sensing motion of the inertial sensor and a case for housing the resonator. The resonator and a wall of the case are defined through an etching process. A typical method of producing the resonator includes etching a baseplate, bonding a wafer to the etched baseplate, through etching the wafer to form a planar mechanical resonator and the wall of the case and bonding an end cap wafer to the wall to complete the case.

  8. Gestational age

    Science.gov (United States)

    Fetal age - gestational age; Gestation; Neonatal gestational age; Newborn gestational age ... Gestational age can be determined before or after birth. Before birth, your health care provider will use ultrasound to ...

  9. Ageing and vascular ageing

    OpenAIRE

    2006-01-01

    There is an age related decline in various physiological processes. Vascular ageing is associated with changes in the mechanical and the structural properties of the vascular wall, which leads to the loss of arterial elasticity and reduced arterial compliance. Arterial compliance can be measured by different parameters like pulse wave velocity, augmentation index, and systemic arterial compliance. There is evidence that arterial compliance is reduced in disease states such as hypertension, di...

  10. Spin coupling and resonance

    NARCIS (Netherlands)

    Zielinski, M.L.; van Lenthe, J.H.

    2008-01-01

    The resonating block localize wave function (RBLW) method is introduced, a resonating modification of the block localized wave functions introduced by Mo et al. [Mo, Y.; Peyerimhoff, S. D. J. Chem. Phys. 1998, 109, 1687].This approach allows the evaluation of resonance energies following Pauling’s r

  11. Controlling Parametric Resonance

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Pettersen, Kristin Ytterstad

    2012-01-01

    Parametric resonance is a resonant phenomenon which takes place in systems characterized by periodic variations of some parameters. While seen as a threatening condition, whose onset can drive a system into instability, this chapter advocates that parametric resonance may become an advantage if t...

  12. Ovenized microelectromechanical system (MEMS) resonator

    Science.gov (United States)

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  13. Magnetic resonance energy and topological resonance energy.

    Science.gov (United States)

    Aihara, Jun-Ichi

    2016-04-28

    Ring-current diamagnetism of a polycyclic π-system is closely associated with thermodynamic stability due to the individual circuits. Magnetic resonance energy (MRE), derived from the ring-current diamagnetic susceptibility, was explored in conjunction with graph-theoretically defined topological resonance energy (TRE). For many aromatic molecules, MRE is highly correlative with TRE with a correlation coefficient of 0.996. For all π-systems studied, MRE has the same sign as TRE. The only trouble with MRE may be that some antiaromatic and non-alternant species exhibit unusually large MRE-to-TRE ratios. This kind of difficulty can in principle be overcome by prior geometry-optimisation or by changing spin multiplicity. Apart from the semi-empirical resonance-theory resonance energy, MRE is considered as the first aromatic stabilisation energy (ASE) defined without referring to any hypothetical polyene reference.

  14. Ageing and vascular ageing

    Science.gov (United States)

    Jani, B; Rajkumar, C

    2006-01-01

    There is an age related decline in various physiological processes. Vascular ageing is associated with changes in the mechanical and the structural properties of the vascular wall, which leads to the loss of arterial elasticity and reduced arterial compliance. Arterial compliance can be measured by different parameters like pulse wave velocity, augmentation index, and systemic arterial compliance. There is evidence that arterial compliance is reduced in disease states such as hypertension, diabetes, and end stage renal failure. Changes in arterial compliance can be present before the clinical manifestation of cardiovascular disease. Pharmacological and non‐pharmacological measures have been shown to improve arterial compliance. Arterial compliance may constitute an early cardiovascular risk marker and may be useful in assessing the effects of drugs on the cardiovascular system. Pharmacogenetics and genetics of arterial compliance in the future will improve our knowledge and understanding about vascular ageing. PMID:16754702

  15. Aging Brain, Aging Mind.

    Science.gov (United States)

    Selkoe, Dennis J.

    1992-01-01

    Discusses the aging process related to physical changes of the human neural structure involved in learning, memory, and reasoning. Presents evidence that indicates such alterations do not necessarily signal the decline in cognitive function. Vignettes provide images of brain structures involved in learning, memory, and reasoning; hippocampal…

  16. The resonant body transistor.

    Science.gov (United States)

    Weinstein, Dana; Bhave, Sunil A

    2010-04-14

    This paper introduces the resonant body transistor (RBT), a silicon-based dielectrically transduced nanoelectromechanical (NEM) resonator embedding a sense transistor directly into the resonator body. Combining the benefits of FET sensing with the frequency scaling capabilities and high quality factors (Q) of internal dielectrically transduced bar resonators, the resonant body transistor achieves >10 GHz frequencies and can be integrated into a standard CMOS process for on-chip clock generation, high-Q microwave circuits, fundamental quantum-state preparation and observation, and high-sensitivity measurements. An 11.7 GHz bulk-mode RBT is demonstrated with a quality factor Q of 1830, marking the highest frequency acoustic resonance measured to date on a silicon wafer.

  17. Dynamically generated resonances

    CERN Document Server

    Oset, E; Sarkar, S; Sun, Bao Xi; Vacas, M J Vicente; González, P; Vijande, J; Jido, D; Sekihara, T; Torres, A Martinez; Khemchandani, K

    2009-01-01

    In this talk I report on recent work related to the dynamical generation of baryonic resonances, some made up from pseudoscalar meson-baryon, others from vector meson-baryon and a third type from two meson-one baryon systems. We can establish a correspondence with known baryonic resonances, reinforcing conclusions previously drawn and bringing new light on the nature of some baryonic resonances of higher mass.

  18. Electron paramagnetic resonance

    CERN Document Server

    Al'tshuler, S A

    2013-01-01

    Electron Paramagnetic Resonance is a comprehensive text on the field of electron paramagnetic resonance, covering both the theoretical background and the results of experiment. This book is composed of eight chapters that cover theoretical materials and experimental data on ionic crystals, since these are the materials that have been most extensively studied by the methods of paramagnetic resonance. The opening chapters provide an introduction to the basic principles of electron paramagnetic resonance and the methods of its measurement. The next chapters are devoted to the theory of spectra an

  19. Split ring resonator resonance assisted terahertz antennas

    CERN Document Server

    Galal, Hossam; Vitiello, Miriam S

    2016-01-01

    We report on the computational development of novel architectures of low impedance broadband antennas, for efficient detection of Terahertz (THz) frequency beams. The conceived Split Ring Resonator Resonance Assisted (SRR RA) antennas are based on both a capacitive and inductive scheme, exploiting a 200 Ohm and 400 Ohm impedance, respectively. Moreover, the impedance is tunable by varying the coupling parameters in the exploited geometry, allowing for better matching with the detector circuit for maximum power extraction. Our simulation results have been obtained by assuming a 1.5 THz operation frequency.

  20. Cognition and brain functional aging

    Directory of Open Access Journals (Sweden)

    Hui-jie LI

    2014-03-01

    Full Text Available China has the largest population of elderly adults. Meanwhile, it is one of the countries showing fastest aging speed in the world. Aging processing is always companied with a series of brain structural and functional changes, which result in the decline of processing speed, working memory, long-term memory and executive function, etc. The studies based on functional magnetic resonance imaging (fMRI found certain aging effects on brain function activation, spontaneous activity and functional connectivity in old people. However, few studies have explored the brain functional curve during the aging process while most previous studies explored the differences in the brain function between young people and old people. Delineation of the human brain functional aging curve will promote the understanding of brain aging mechanisms and support the normal aging monitoring and early detection of abnormal aging changes. doi: 10.3969/j.issn.1672-6731.2014.03.005

  1. Resonance and Fractal Geometry

    NARCIS (Netherlands)

    Broer, Henk W.

    2012-01-01

    The phenomenon of resonance will be dealt with from the viewpoint of dynamical systems depending on parameters and their bifurcations. Resonance phenomena are associated to open subsets in the parameter space, while their complement corresponds to quasi-periodicity and chaos. The latter phenomena oc

  2. Fundamentals of nanomechanical resonators

    CERN Document Server

    Schmid, Silvan; Roukes, Michael Lee

    2016-01-01

    This authoritative book introduces and summarizes the latest models and skills required to design and optimize nanomechanical resonators, taking a top-down approach that uses macroscopic formulas to model the devices. The authors cover the electrical and mechanical aspects of nano electromechanical system (NEMS) devices. The introduced mechanical models are also key to the understanding and optimization of nanomechanical resonators used e.g. in optomechanics. Five comprehensive chapters address: The eigenmodes derived for the most common continuum mechanical structures used as nanomechanical resonators; The main sources of energy loss in nanomechanical resonators; The responsiveness of micro and nanomechanical resonators to mass, forces, and temperature; The most common underlying physical transduction mechanisms; The measurement basics, including amplitude and frequency noise. The applied approach found in this book is appropriate for engineering students and researchers working with micro and nanomechanical...

  3. Monolithic MACS micro resonators

    Science.gov (United States)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  4. Neutrino Production of Resonances

    CERN Document Server

    Paschos, E A; Yu, J Y; Paschos, Emmanuel A.; Sakuda, Makoto; Yu, Ji--Young

    2004-01-01

    We take a fresh look at the analysis of resonance production by neutrinos. We consider three resonances $P_{33}, P_{11}$ and $S_{11}$ with a detailed discussion of their form factors. The article presents results for free proton and neutron targets and discusses the corrections which appear on nuclear targets. The Pauli suppression factor is derived in the Fermi gas model and shown to apply to resonance production. The importance of the various resonances is demonstrated with numerical calculations. The $\\Delta$-resonance is described by two formfactors and its differential cross sections are compared with experimental data. The article is self-contained and could be helpful to readers who wish to reproduce and use these cross sections.

  5. Rural Aging

    Science.gov (United States)

    ... Rural Health > Topics & States > Topics View more Rural Aging The nation's population is aging, and with that change comes increased healthcare needs. ... Disease Control and Prevention report, The State of Aging and Health in America 2013 , the population 65 ...

  6. Resonance Radiation and Excited Atoms

    Science.gov (United States)

    Mitchell, Allan C. G.; Zemansky, Mark W.

    2009-06-01

    1. Introduction; 2. Physical and chemical effects connected with resonance radiation; 3. Absorption lines and measurements of the lifetime of the resonance state; 4. Collision processes involving excited atoms; 5. The polarization of resonance radiation; Appendix; Index.

  7. Advances in magnetic resonance 10

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.

  8. Tunable multiwalled nanotube resonator

    Science.gov (United States)

    Zettl, Alex K.; Jensen, Kenneth J.; Girit, Caglar; Mickelson, William E.; Grossman, Jeffrey C.

    2011-03-29

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  9. Spin Resonance Strength Calculations

    Science.gov (United States)

    Courant, E. D.

    2009-08-01

    In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

  10. Spin resonance strength calculations

    Energy Technology Data Exchange (ETDEWEB)

    Courant,E.D.

    2008-10-06

    In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

  11. Resonant power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2012-01-01

    This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them wit

  12. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  13. Characteristics of resonance in heart rate variability stimulated by biofeedback.

    Science.gov (United States)

    Vaschillo, Evgeny G; Vaschillo, Bronya; Lehrer, Paul M

    2006-06-01

    As we previously reported, resonant frequency heart rate variability biofeedback increases baroreflex gain and peak expiratory flow in healthy individuals and has positive effects in treatment of asthma patients. Biofeedback readily produces large oscillations in heart rate, blood pressure, vascular tone, and pulse amplitude via paced breathing at the specific natural resonant frequency of the cardiovascular system for each individual. This paper describes how resonance properties of the cardiovascular system mediate the effects of heart rate variability biofeedback. There is evidence that resonant oscillations can train autonomic reflexes to provide therapeutic effect. The paper is based on studies described in previous papers. Here, we discuss the origin of the resonance phenomenon, describe our procedure for determining an individual's resonant frequency, and report data from 32 adult asthma patients and 24 healthy adult subjects, showing a negative relationship between resonant frequency and height, and a lower resonant frequency in men than women, but no relationship between resonant frequency and age, weight, or presence of asthma. Resonant frequency remains constant across 10 sessions of biofeedback training. It appears to be related to blood volume.

  14. Resonant Diphoton Phenomenology Simplified

    CERN Document Server

    Panico, Giuliano; Wulzer, Andrea

    2016-01-01

    A framework is proposed to describe resonant diphoton phenomenology at hadron colliders in full generality. It can be employed for a comprehensive model-independent interpretation of the experimental data. Within the general framework, few benchmark scenarios are defined as representative of the various phenomenological options and/or of motivated new physics scenarios. Their usage is illustrated by performing a characterization of the 750 GeV excess, based on a recast of available experimental results. We also perform an assessment of which properties of the resonance could be inferred, after discovery, by a careful experimental study of the diphoton distributions. These include the spin J of the new particle and its dominant production mode. Partial information on its CP-parity can also be obtained, but only for J >= 2. The complete determination of the resonance CP properties requires studying the pattern of the initial state radiation that accompanies the resonance production.

  15. Resonances in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, Matthias F. M.; Lange, Jens Sören; Pennington, Michael; Bettoni, Diego; Brambilla, Nora; Crede, Volker; Eidelman, Simon; Gillitzer, Albrecht; Gradl, Wolfgang; Lang, Christian B.; Metag, Volker; Nakano, Takashi; Nieves, Juan; Neubert, Sebastian; Oka, Makoto; Olsen, Stephen L.; Pappagallo, Marco; Paul, Stephan; Pelizäus, Marc; Pilloni, Alessandro; Prencipe, Elisabetta; Ritman, Jim; Ryan, Sinead; Thoma, Ulrike; Uwer, Ulrich; Weise, Wolfram

    2016-04-01

    We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015 (Fig.~1). A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions; what is needed to understand the physics of resonances in QCD?; where does QCD lead us to expect resonances with exotic quantum numbers?; and what experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with up, down and strange quark content were considered. For heavy-light and heavy-heavy meson systems, those with charm quarks were the focus.This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.

  16. Resonant Thermoelectric Nanophotonics

    CERN Document Server

    Mauser, Kelly W; Kim, Seyoon; Fleischman, Dagny; Atwater, Harry A

    2016-01-01

    Photodetectors are typically based on photocurrent generation from electron-hole pairs in semiconductor structures and on bolometry for wavelengths that are below bandgap absorption. In both cases, resonant plasmonic and nanophotonic structures have been successfully used to enhance performance. In this work, we demonstrate subwavelength thermoelectric nanostructures designed for resonant spectrally selective absorption, which creates large enough localized temperature gradients to generate easily measureable thermoelectric voltages. We show that such structures are tunable and are capable of highly wavelength specific detection, with an input power responsivity of up to 119 V/W (referenced to incident illumination), and response times of nearly 3 kHz, by combining resonant absorption and thermoelectric junctions within a single structure, yielding a bandgap-independent photodetection mechanism. We report results for both resonant nanophotonic bismuth telluride-antimony telluride structures and chromel-alumel...

  17. Resonance Production in Jet

    CERN Document Server

    Markert, Christina

    2007-01-01

    Hadronic resonances with short life times and strong coupling to the dense medium may exhibit mass shifts and width broadening as signatures of chiral symmetry restoration at the phase transition between hadronic and partonic matter. Resonances with different lifetimes are also used to extract information about the time evolution and temperature of the expanding hadronic medium. In order to collect information about the early stage (at the phase transition) of a heavy-ion collision, resonances and decay particles which are unaffected by the hadronic medium have to be used. We explore a possible new technique to extract signals from the early stage through the selection of resonances from jets. A first attempt of this analysis, using the reconstructed $\\phi$(1020) from 200 GeV Au+Au collisions in STAR, is presented.

  18. Triple-resonant transducers.

    Science.gov (United States)

    Butler, Stephen C

    2012-06-01

    A detailed analysis is presented of two novel multiple-resonant transducers which produce a wider transmit response than that of a conventional Tonpilz-type transducer. These multi-resonant transducers are Tonpilz-type longitudinal vibrators that produce three coupled resonances and are referred to as triple-resonant transducers (TRTs). One of these designs is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, second central mass, second compliant spring, and a piston-radiating head mass. The other TRT design is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, and head mass with a quarter-wave matching layer of poly(methyl methacrylate) on the head mass. Several prototype transducer element designs were fabricated that demonstrated proof-of-concept.

  19. Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Robert H. Morris

    2014-11-01

    Full Text Available Magnetic Resonance finds countless applications, from spectroscopy to imaging, routinely in almost all research and medical institutions across the globe. It is also becoming more frequently used for specific applications in which the whole instrument and system is designed for a dedicated application. With beginnings in borehole logging for the petro-chemical industry Magnetic Resonance sensors have been applied to fields as varied as online process monitoring for food manufacture and medical point of care diagnostics. This great diversity is seeing exciting developments in magnetic resonance sensing technology published in application specific journals where they are often not seen by the wider sensor community. It is clear that there is enormous interest in magnetic resonance sensors which represents a significant growth area. The aim of this special edition of Sensors was to address the wide distribution of relevant articles by providing a forum to disseminate cutting edge research in this field in a single open source publication.[...

  20. Resonances in QCD

    Science.gov (United States)

    Lutz, Matthias F. M.; Lange, Jens Sören; Pennington, Michael; Bettoni, Diego; Brambilla, Nora; Crede, Volker; Eidelman, Simon; Gillitzer, Albrecht; Gradl, Wolfgang; Lang, Christian B.; Metag, Volker; Nakano, Takashi; Nieves, Juan; Neubert, Sebastian; Oka, Makoto; Olsen, Stephen L.; Pappagallo, Marco; Paul, Stephan; Pelizäus, Marc; Pilloni, Alessandro; Prencipe, Elisabetta; Ritman, Jim; Ryan, Sinead; Thoma, Ulrike; Uwer, Ulrich; Weise, Wolfram

    2016-04-01

    We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015. A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions: What is needed to understand the physics of resonances in QCD? Where does QCD lead us to expect resonances with exotic quantum numbers? What experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with up, down and strange quark content were considered. For heavy-light and heavy-heavy meson systems, those with charm quarks were the focus. This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.

  1. Resonances in QCD

    CERN Document Server

    Lutz, Matthias F M; Pennington, Michael; Bettoni, Diego; Brambilla, Nora; Crede, Volker; Eidelman, Simon; Gillitzer, Albrecht; Gradl, Wolfgang; Lang, Christian B; Metag, Volker; Nieves, Juan; Neubert, Sebastian; Oka, Makoto; Olsen, Steve L; Pappagallo, Marco; Paul, Stephan; Pelizäus, Marc; Pilloni, Alessandro; Prencipe, Elisabetta; Ritman, Jim; Ryan, Sinead; Thoma, Ulrike; Uwer, Ulrich; Weise, Wolfram

    2015-01-01

    We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015. A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions: What is needed to understand the physics of resonances in QCD? Where does QCD lead us to expect resonances with exotic quantum numbers? What experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with ${\\it up}$, ${\\it down}$ and ${\\it strange}$ quark content were considered. For heavy-light and heavy-heavy meson systems, those with ${\\it charm}$ quarks were the focus. This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.

  2. Lattices of dielectric resonators

    CERN Document Server

    Trubin, Alexander

    2016-01-01

    This book provides the analytical theory of complex systems composed of a large number of high-Q dielectric resonators. Spherical and cylindrical dielectric resonators with inferior and also whispering gallery oscillations allocated in various lattices are considered. A new approach to S-matrix parameter calculations based on perturbation theory of Maxwell equations, developed for a number of high-Q dielectric bodies, is introduced. All physical relationships are obtained in analytical form and are suitable for further computations. Essential attention is given to a new unified formalism of the description of scattering processes. The general scattering task for coupled eigen oscillations of the whole system of dielectric resonators is described. The equations for the  expansion coefficients are explained in an applicable way. The temporal Green functions for the dielectric resonator are presented. The scattering process of short pulses in dielectric filter structures, dielectric antennas  and lattices of d...

  3. Piezoelectric MEMS resonators

    CERN Document Server

    Piazza, Gianluca

    2017-01-01

    This book introduces piezoelectric microelectromechanical (pMEMS) resonators to a broad audience by reviewing design techniques including use of finite element modeling, testing and qualification of resonators, and fabrication and large scale manufacturing techniques to help inspire future research and entrepreneurial activities in pMEMS. The authors discuss the most exciting developments in the area of materials and devices for the making of piezoelectric MEMS resonators, and offer direct examples of the technical challenges that need to be overcome in order to commercialize these types of devices. Some of the topics covered include: Widely-used piezoelectric materials, as well as materials in which there is emerging interest Principle of operation and design approaches for the making of flexural, contour-mode, thickness-mode, and shear-mode piezoelectric resonators, and examples of practical implementation of these devices Large scale manufacturing approaches, with a focus on the practical aspects associate...

  4. Perspective on resonances of metamaterials.

    Science.gov (United States)

    Min, Li; Huang, Lirong

    2015-07-27

    Electromagnetic resonance as the most important characteristic of metamaterials enables lots of exotic phenomena, such as invisible, negative refraction, man-made magnetism, etc. Conventional LC-resonance circuit model as the most authoritative and classic model is good at explaining and predicting the fundamental resonance wavelength of a metamaterial, while feels hard for high-order resonances, especially for resonance intensity (strength of resonance, determining on the performance and efficiency of metamaterial-based devices). In present work, via an easy-to-understand mass-spring model, we present a different and comprehensive insight for the resonance mechanism of metamaterials, through which both the resonance wavelengths (including the fundamental and high-order resonance wavelengths) and resonance intensities of metamaterials can be better understood. This developed theory has been well verified by different-material and different-structure resonators. This perspective will provide a broader space for exploring novel optical devices based on metamaterials (or metasurfaces).

  5. Geometric Stochastic Resonance

    CERN Document Server

    Ghosh, Pulak Kumar; Savel'ev, Sergey E; Nori, Franco

    2015-01-01

    A Brownian particle moving across a porous membrane subject to an oscillating force exhibits stochastic resonance with properties which strongly depend on the geometry of the confining cavities on the two sides of the membrane. Such a manifestation of stochastic resonance requires neither energetic nor entropic barriers, and can thus be regarded as a purely geometric effect. The magnitude of this effect is sensitive to the geometry of both the cavities and the pores, thus leading to distinctive optimal synchronization conditions.

  6. Hexagonal quartz resonator

    Science.gov (United States)

    Peters, Roswell D. M.

    1982-01-01

    A generally flat, relatively thin AT-cut piezoelectric resonator element structured to minimize the force-frequency effect when mounted and energized in a housing. The resonator is in the form of an equilateral hexagon with the X crystallographic axis of the crystal passing through one set of opposing corners with mounting being effected at an adjacent set of corners respectively .+-.60.degree. away from the X axis which thereby results in a substantially zero frequency shift of the operating frequency.

  7. Resonant dielectric metamaterials

    Science.gov (United States)

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B

    2014-12-02

    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  8. Magnesium and healthy aging.

    Science.gov (United States)

    Veronese, Nicola; Zanforlini, Bruno Micael; Manzato, Enzo; Sergi, Giuseppe

    2015-01-01

    Magnesium (Mg) is relatively stable in the intracellular compartment, although decreases linearly with advancing age. This begs the question as to whether Mg could be used as biomarker of aging. A biomarker of aging is a biological parameter of an organism that, in the absence of disease, better predicts functional capability at a later age than the chronological age. Bone and muscle Mg content might be useful biomarkers, but the need for biopsies and the heterogeneous distribution of Mg in bones and muscles strongly limit the application of these methods in clinical practice. Similar considerations can be made for urinary Mg assessment, particularly after a loading test. Markers of Mg in blood seem fairly unreliable as biomarkers of aging since they are strongly dependent upon renal function, do not reflect the intracellular Mg status, and, in some investigations, are within normal ranges although other Mg parameters are not. Other investigations (e.g. nuclear magnetic resonance with fluorescent probes) seem to be promising, but their availability remains limited.

  9. Effective resonant stability of Mercury

    CERN Document Server

    Sansottera, M; Lemaître, A

    2015-01-01

    Mercury is the unique known planet that is situated in a 3:2 spin-orbit resonance nowadays. Observations and models converge to the same conclusion: the planet is presently deeply trapped in the resonance and situated at the Cassini state $1$, or very close to it. We investigate the complete non-linear stability of this equilibrium, with respect to several physical parameters, in the framework of Birkhoff normal form and Nekhoroshev stability theory. We use the same approach adopted for the 1:1 spin-orbit case with a peculiar attention to the role of Mercury's non negligible eccentricity. The selected parameters are the polar moment of inertia, the Mercury's inclination and eccentricity and the precession rates of the perihelion and node. Our study produces a bound to both the latitudinal and longitudinal librations (of 0.1 radians) for a long but finite time (greatly exceeding the age of the solar system). This is the so-called effective stability time. Our conclusion is that Mercury, placed inside the 3:2 s...

  10. Magnetic resonance imaging of iliotibial band syndrome.

    Science.gov (United States)

    Ekman, E F; Pope, T; Martin, D F; Curl, W W

    1994-01-01

    Seven cases of iliotibial band syndrome and the pathoanatomic findings of each, as demonstrated by magnetic resonance imaging, are presented. These findings were compared with magnetic resonance imaging scans of 10 age- and sex-matched control knees without evidence of lateral knee pain. Magnetic resonance imaging signal consistent with fluid was seen deep to the iliotibial band in the region of the lateral femoral epicondyle in five of the seven cases. Additionally, when compared with the control group, patients with iliotibial band syndrome demonstrated a significantly thicker iliotibial band over the lateral femoral epicondyle (P iliotibial band in the disease group was 5.49 +/- 2.12 mm, as opposed to 2.52 +/- 1.56 mm in the control group. Cadaveric dissections were performed on 10 normal knees to further elucidate the exact nature of the area under the iliotibial band. A potential space, i.e., a bursa, was found between the iliotibial band and the knee capsule. This series suggests that magnetic resonance imaging demonstrates objective evidence of iliotibial band syndrome and can be helpful when a definitive diagnosis is essential. Furthermore, correlated with anatomic dissection, magnetic resonance imaging identifies this as a problem within a bursa beneath the iliotibial band and not a problem within the knee joint.

  11. Age Spots

    Science.gov (United States)

    ... How to Choose the Best Skin Care Products Age Spots Treatment Options Learn more about treatment options ... or black, flat patches of skin. Why treat age spots Physical, emotional and social reasons for treating ...

  12. Not-so-resonant, resonant absorption

    Science.gov (United States)

    Brunel, F.

    1987-07-01

    When an intense electromagnetic wave is incident obliquely on a sharply bounded overdense plasma, strong energy absorption can be accounted for by the electrons that are dragged into the vacuum and sent back into the plasma with velocities v~=vosc. This mechanism is more efficient than usual resonant absorption for vosc/ω>L, with L being the density gradient length. In the very high-intensity CO2-laser-target interaction, this mechanism may account for most of the energy absorption.

  13. Magnetic resonance imaging; Imagerie par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Fontanel, F. [Centre Hospitalier, 40 - Mont-de -Marsan (France); Clerc, T. [Centre Hospitalier Universitaire, 76 - Rouen (France); Theolier, S. [Hospice Civils de Lyon, 69 - Lyon (France); Verdenet, J. [Centre Hospitalier Universitaire, 25 - Besancon (France)

    1997-04-01

    The last improvements in nuclear magnetic resonance imaging are detailed here, society by society with an expose of their different devices. In the future the different technological evolutions will be on a faster acquisition, allowing to reduce the examination time, on the development of a more acute cardiac imaging, of a functional neuro-imaging and an interactive imaging for intervention. With the contrast products, staying a longer time in the vascular area, the angiography will find its place. Finally, the studies on magnetic fields should allow to increase the volume to examine. (N.C.).

  14. Happy Aging

    Institute of Scientific and Technical Information of China (English)

    梁秉中

    2009-01-01

    Aging is a normal physiological process in human life.The decline in the ability to repair and regenerate predisposes the aging person to develop disabling problems in the cardiovascular and skeletal systems.Full awareness of aging problems and advocations on the means to prevent their occurrence are mounting.European and US groups rely on scientific,target-oriented means to treat aging manifestations. Oriental medicine aims at prevention,using nutrition and exercise to maintain internal harmony.

  15. Aging skin.

    Science.gov (United States)

    Bolognia, J L

    1995-01-16

    Aging of the skin is a composite of actinic damage, chronologic aging, and hormonal influences. The majority of changes associated with aging, such as wrinkles and solar lentigines ("liver spots"), are due to photoaging and reflect cumulative sun exposure as well as skin pigmentation. Classically, chronologic aging includes those cutaneous changes that occur in non-sun-exposed areas, such as the buttocks, and are observed in both men and women. A clinical example would be soft tissue sagging due to elastic fiber degeneration. In women, investigations into the effect of hormones on aging of the skin have concentrated on estrogens; in men, there have been a limited number of studies on the influence of testosterone. The latter have shown an age-dependent decrease in tissue androgens in pubic skin, but not scrotal or thigh skin. To date, age has not been shown to have an effect on androgen receptor binding, although a decrease in foreskin 5 alpha-reductase activity with increasing age has been described. In fibroblast cultures from foreskins, there have been conflicting results as to whether 5 alpha-reductase activity decreases in an age-dependent manner. Some of the skin changes that have been categorized as secondary to chronologic aging, such as decreased sebaceous gland activity and decreased hair growth, may actually represent a decline in the concentration of tissue androgens with increasing age. The influence of androgens on age-related changes in keratinocyte and fibroblast function remains speculative.

  16. Skin Aging

    Science.gov (United States)

    Your skin changes as you age. You might notice wrinkles, age spots and dryness. Your skin also becomes thinner and loses fat, making it ... heal, too. Sunlight is a major cause of skin aging. You can protect yourself by staying out ...

  17. Ageing Polulations

    DEFF Research Database (Denmark)

    Christiansen, Terkel; Lauridsen, Jørgen Trankjær; Bech, Mickael

    2013-01-01

    An ageing society is characterised by an increasing median age of the population. The purpose of this chapter is to document the existing knowledge about the association between population ageing and health care expenditure, and to supplement this overview by a summary of our original research. S...

  18. Hyperbolic Resonances of Metasurface Cavities

    CERN Document Server

    Keene, David

    2015-01-01

    We propose a new class of optical resonator structures featuring one or two metasurface reflectors or metacavities and predict that such resonators support novel hyperbolic resonances. As an example of such resonances we introduce hyperbolic Tamm plasmons (HTPs) and hyperbolic Fabry-Perot resonances (HFPs). The hyperbolic optical modes feature low-loss incident power re-distribution over TM and TE polarization output channels, clover-leaf anisotropic dispersion, and other unique properties which are tunable and are useful for multiple applications.

  19. Overview of baryon resonances

    Directory of Open Access Journals (Sweden)

    Downie E.J.

    2014-06-01

    Full Text Available The quest to understand the physics of any system cannot be said to be complete as long as one cannot predict and fully understand its resonance spectrum. Despite this, due to the experimental challenge of the required double polarization measurements and the difficulty in achieving unambiguous, model-independent extraction and interpretation of the nucleon resonance spectrum of many broad and overlapping resonances, understanding of the structure and dynamics of the nucleon has suffered. The recent improvement in statistical quality and kinematic range of the data made available by such full-solid-angle systems as the CB and TAPS constellation at MAMI, coupled with the high flux polarized photon beam provided by the Glasgow Photon Tagger, and the excellent properties of the Mainz Frozen Spin Target, when paired with new developments in Partial Wave Analysis (PWA methodology make this a very exciting and fruitful time in nucleon resonance studies. Here the recent influx of data and PWA developments are summarized, and the requirements for a complete, unambiguous PWA solution over the first and second resonance region are briefly reviewed.

  20. Split-ball resonator

    CERN Document Server

    Kuznetsov, Arseniy I; Fu, Yuan Hsing; Viswanathan, Vignesh; Rahmani, Mohsen; Valuckas, Vytautas; Kivshar, Yuri; Pickard, Daniel S; Lukiyanchuk, Boris

    2014-01-01

    We introduce a new concept of split-ball resonator and demonstrate a strong omnidirectional magnetic dipole response for both gold and silver spherical plasmonic nanoparticles with nanometer-scale cuts. Tunability of the magnetic dipole resonance throughout the visible spectral range is demonstrated by a change of the depth and width of the nanoscale cut. We realize this novel concept experimentally by employing the laser-induced transfer method to produce near-perfect spheres and helium ion beam milling to make cuts with the nanometer resolution. Due to high quality of the spherical particle shape, governed by strong surface tension forces during the laser transfer process, and the clean, straight side walls of the cut made by helium ion milling, magnetic resonance is observed at 600 nm in gold and at 565 nm in silver nanoparticles. Structuring arbitrary features on the surface of ideal spherical resonators with nanoscale dimensions provides new ways of engineering hybrid resonant modes and ultra-high near-f...

  1. The Resonant Transneptunian Populations

    CERN Document Server

    Gladman, B; Petit, J-M; Kavelaars, J; Jones, R L; Parker, J Wm; Van Laerhoven, C; Nicholson, P; Rousselot, P; Bieryla, A; Ashby, M L N

    2012-01-01

    The transneptunian objects (TNOs) trapped in mean-motion resonances with Neptune were likely emplaced there during planet migration late in the giant-planet formation process. We perform detailed modelling of the resonant objects detected in the Canada-France Ecliptic Plane Survey (CFEPS) in order to provide population estimates and, for some resonances, constrain the complex internal orbital element distribution. Detection biases play a critical role because phase relationships with Neptune make object discovery more likely at certain longitudes. This paper discusses the 3:2, 5:2, 2:1, 3:1, 5:1, 4:3, 5:3, 7:3, 5:4, and 7:4 mean-motion resonances, all of which had CFEPS detections, along with our upper limit on 1:1 Neptune Trojans (which is consistent with their small population estimated elsewhere). For the plutinos (TNOs in the 3:2 resonance) we refine the orbital element distribution given in Kavelaars et al. (2009) and show that steep H-magnitude distributions (N(H) proportional to 10aH, with a=0.8-0.9) a...

  2. Resonance vector mode locking

    CERN Document Server

    Kolpakov, Stanislav A; Loika, Yuri; Tarasov, Nikita; Kalashnikov, Vladimir; Agrawal, Govind P

    2015-01-01

    A mode locked fibre laser as a source of ultra-stable pulse train has revolutionised a wide range of fundamental and applied research areas by offering high peak powers, high repetition rates, femtosecond range pulse widths and a narrow linewidth. However, further progress in linewidth narrowing seems to be limited by the complexity of the carrier-envelope phase control. Here for the first time we demonstrate experimentally and theoretically a new mechanism of resonance vector self-mode locking where tuning in-cavity birefringence leads to excitation of the longitudinal modes sidebands accompanied by the resonance phase locking of sidebands with the adjacent longitudinal modes. An additional resonance with acoustic phonons provides the repetition rate tunability and linewidth narrowing down to Hz range that drastically reduces the complexity of the carrier-envelope phase control and so will open the way to advance lasers in the context of applications in metrology, spectroscopy, microwave photonics, astronomy...

  3. Quartz resonator processing system

    Science.gov (United States)

    Peters, Roswell D. M.

    1983-01-01

    Disclosed is a single chamber ultra-high vacuum processing system for the oduction of hermetically sealed quartz resonators wherein electrode metallization and sealing are carried out along with cleaning and bake-out without any air exposure between the processing steps. The system includes a common vacuum chamber in which is located a rotatable wheel-like member which is adapted to move a plurality of individual component sets of a flat pack resonator unit past discretely located processing stations in said chamber whereupon electrode deposition takes place followed by the placement of ceramic covers over a frame containing a resonator element and then to a sealing stage where a pair of hydraulic rams including heating elements effect a metallized bonding of the covers to the frame.

  4. Reconfigurable optical routers based on Coupled Resonator Induced Transparency resonances.

    Science.gov (United States)

    Mancinelli, M; Bettotti, P; Fedeli, J M; Pavesi, L

    2012-10-08

    The interferometric coupling of pairs of resonators in a resonator sequence generates coupled ring induced transparency (CRIT) resonances. These have quality factors an order of magnitude greater than those of single resonators. We show that it is possible to engineer CRIT resonances in tapered SCISSOR (Side Coupled Integrated Space Sequence of Resonator) to realize fast and efficient reconfigurable optical switches and routers handling several channels while keeping single channel addressing capabilities. Tapered SCISSORs are fabricated in silicon-on-insulator technology. Furthermore, tapered SCISSORs show multiple-channel switching behavior that can be exploited in DWDM applications.

  5. Acoustic Fano resonators

    KAUST Repository

    Amin, Muhammad

    2014-07-01

    The resonances with asymmetric Fano line-shapes were originally discovered in the context of quantum mechanics (U. Fano, Phys. Rev., 124, 1866-1878, 1961). Quantum Fano resonances were generated from destructive interference of a discrete state with a continuum one. During the last decade this concept has been applied in plasmonics where the interference between a narrowband polariton and a broader one has been used to generate electromagnetically induced transparency (EIT) (M. Rahmani, et al., Laser Photon. Rev., 7, 329-349, 2013).

  6. Pygmy resonances and nucleosynthesis

    CERN Document Server

    Tsoneva, Nadia

    2014-01-01

    A microscopic theoretical approach based on a self-consistent density functional theory for the nuclear ground state and QRPA formalism extended with multi-phonon degrees of freedom for the nuclear excited states is implemented in investigations of new low-energy modes called pygmy resonances. Advantage of the method is the unified description of low-energy multiphonon excitations, pygmy resonances and core polarization effects. This is found of crucial importance for the understanding of the fine structure of nuclear response functions at low energies. Aspects of the precise knowledge of nuclear response functions around the neutron threshold are discussed in a connection to nucleosynthesis.

  7. Nanoantenna using mechanical resonance

    KAUST Repository

    Chang Hwa Lee,

    2010-11-01

    Nanoantenna using mechanical resonance vibration is made from an indium tin oxide (ITO) coated vertically aligned nanorod array. Only this structure works as a radio with demodulator without any electrical circuit using field emission phenomenon. A top-down fabrication method of an ITO coated nanorod array is proposed using a modified UV lithography. The received radio frequency and the resonance frequency of nanoantenna can be controlled by the fabrication condition through the height of a nanorod array. The modulated signals are received successfully with the transmission carrier wave frequency (248MHz) and the proposed nanoantenna is expected to be used in communication system for ultra small scale sensor. ©2010 IEEE.

  8. Hadronic Resonances from STAR

    Directory of Open Access Journals (Sweden)

    Wada Masayuki

    2012-11-01

    Full Text Available The results of resonance particle productions (ρ0, ω, K*, ϕ, Σ*, and Λ* measured by the STAR collaboration at RHIC from various colliding systems and energies are presented. Measured mass, width, 〈pT〉, and yield of those resonances are reviewed. No significant mass shifts or width broadening beyond the experiment uncertainties are observed. New measurements of ϕ and ω from leptonic decay channels are presented. The yields from leptonic decay channels are compared with the measurements from hadronic decay channels and the two results are consistent with each other.

  9. On the Erigone family and the $z_2$ secular resonance

    CERN Document Server

    Carruba, Valerio; Winter, Othon C

    2015-01-01

    The Erigone family is a C-type group in the inner main belt. Its age has been estimated by several researchers to be less then 300 My, so it is a relatively young cluster. Yarko-YORP Monte Carlo methods to study the chronology of the Erigone family confirm results obtained by other groups. The Erigone family, however, is also characterized by its interaction with the $z_2$ secular resonance. While less than 15% of its members are currently in librating states of this resonance, the number of objects, members of the dynamical group, in resonant states is high enough to allow to use the study of dynamics inside the $z_2$ resonance to set constraints on the family age. Like the ${\

  10. Magnetic resonance of phase transitions

    CERN Document Server

    Owens, Frank J; Farach, Horacio A

    1979-01-01

    Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

  11. Population aging.

    Science.gov (United States)

    1999-04-01

    This paper focuses on the impact of population aging in China, the most densely populated country in the world. Statistics indicate that by the end of 1998, 83.75 million out of the 1.248 billion Chinese people will be over 65 years old. According to the UN standards, China will soon become an aging society. The aging population poses several challenges to the country with the greatest challenge being the increasing social responsibility to care for the aged. With the undeveloped legislative framework to protect the interests of the aged and the serious drawbacks in the pension system to cater only to the income part and not the service part of the aged, China is not yet ready for the advent of aging. Violation of the rights of senior citizens is still very rampant despite enactment of the law on Protection of the Rights of the Elderly in 1996. Moreover, China is not economically ready to become an aging society. China faces this challenge by adopting a three-pronged approach to solve the problem namely: family support, establishment of nursing homes, and creating a social security framework that addresses the needs of the society suited to the Chinese condition. It is believed that with the growing economy of the country and the rising income of its people, a comprehensive social security net will be created to take care of the aged.

  12. Resonant filtered fiber amplifiers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Laurila, Marko; Olausson, Christina Bjarnal Thulin

    2013-01-01

    In this paper we present our recent result on utilizing resonant/bandgap fiber designs to achieve high performance ytterbium doped fiber amplifers for achieving diffraction limited beam quality in large mode area fibers, robust bending performance and gain shaping for long wavelength operation...

  13. Resonant MEMS tunable VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug; Semenova, Elizaveta;

    2013-01-01

    We demonstrate how resonant excitation of a microelectro-mechanical system can be used to increase the tuning range of a vertical-cavity surface-emitting laser two-fold by enabling both blue- and red-shifting of the wavelength. In this way a short-cavity design enabling wide tuning range can be r...

  14. Neutron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F

    2005-06-15

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  15. Electrically detected ferromagnetic resonance

    NARCIS (Netherlands)

    Goennenwein, S.T.B.; Schink, S.W.; Brandlmaier, A.; Boger, A.; Opel, M.; Gross, R.; Keizer, R.S.; Klapwijk, T.M.; Gupta, A.; Huebl, H.; Bihler, C.; Brandt, M.S.

    2007-01-01

    We study the magnetoresistance properties of thin ferromagnetic CrO2 and Fe3O4 films under microwave irradiation. Both the sheet resistance ρ and the Hall voltage VHall characteristically change when a ferromagnetic resonance (FMR) occurs in the film. The electrically detected ferromagnetic resonanc

  16. Simulation of quartz resonators

    Science.gov (United States)

    Weinmann, M.; Radius, R.; Mohr, R.

    Quartz resonators are suitable as novel sensor elements in the field of profilometry and three dimensional measurement techniques. This application requires a tailoring of the oscillator circuit which is performed by a network analysis program. The equivalent network parameters are computed by a finite element analysis. The mechanical loading of the quartz is modeled by a viscous damping approach.

  17. Resonant scanning mechanism

    Science.gov (United States)

    Wallace, John; Newman, Mike; Gutierrez, Homero; Hoffman, Charlie; Quakenbush, Tim; Waldeck, Dan; Leone, Christopher; Ostaszewski, Miro

    2014-10-01

    Ball Aerospace & Technologies Corp. developed a Resonant Scanning Mechanism (RSM) capable of combining a 250- Hz resonant scan about one axis with a two-hertz triangular scan about the orthogonal axis. The RSM enables a rapid, high-density scan over a significant field of regard (FOR) while minimizing size, weight, and power requirements. The azimuth scan axis is bearing mounted allowing for 30° of mechanical travel, while the resonant elevation axis is flexure and spring mounted with five degrees of mechanical travel. Pointing-knowledge error during quiescent static pointing at room temperature across the full range is better than 100 μrad RMS per axis. The compact design of the RSM, roughly the size of a soda can, makes it an ideal mechanism for use on low-altitude aircraft and unmanned aerial vehicles. Unique aspects of the opto-mechanical design include i) resonant springs which allow for a high-frequency scan axis with low power consumption; and ii) an independent lower-frequency scan axis allowing for a wide FOR. The pointing control system operates each axis independently and employs i) a position loop for the azimuth axis; and ii) a unique combination of parallel frequency and amplitude control loops for the elevation axis. All control and pointing algorithms are hosted on a 200-MHz microcontroller with 516 KB of RAM on a compact 3"×4" digital controller, also of Ball design.

  18. Folded waveguide resonator

    DEFF Research Database (Denmark)

    2013-01-01

    A waveguide resonator comprising a number of side walls defining a cavity enclosed by said sidewalls defining the cavity; and two or more conductive plates extending into the cavity, each conductive plate having a first side and a second side opposite the first side, and wherein the conductive...

  19. Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  20. Wireless ferroelectric resonating sensor.

    Science.gov (United States)

    Viikari, Ville; Seppa, Heikki; Mattila, Tomi; Alastalo, Ari

    2010-04-01

    This paper presents a passive wireless resonating sensor that is based on a ferroelectric varactor. The sensor replies with its data at an intermodulation frequency when a reader device illuminates it at 2 closely located frequencies. The paper derives a theoretical equation for the response of such a sensor, verifies the theory by simulations, and demonstrates a temperature sensor based on a ferroelectric varactor.

  1. Single spin magnetic resonance

    Science.gov (United States)

    Wrachtrup, Jörg; Finkler, Amit

    2016-08-01

    Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.

  2. Aging and functional brain networks

    Energy Technology Data Exchange (ETDEWEB)

    Tomasi D.; Tomasi, D.; Volkow, N.D.

    2011-07-11

    Aging is associated with changes in human brain anatomy and function and cognitive decline. Recent studies suggest the aging decline of major functional connectivity hubs in the 'default-mode' network (DMN). Aging effects on other networks, however, are largely unknown. We hypothesized that aging would be associated with a decline of short- and long-range functional connectivity density (FCD) hubs in the DMN. To test this hypothesis, we evaluated resting-state data sets corresponding to 913 healthy subjects from a public magnetic resonance imaging database using functional connectivity density mapping (FCDM), a voxelwise and data-driven approach, together with parallel computing. Aging was associated with pronounced long-range FCD decreases in DMN and dorsal attention network (DAN) and with increases in somatosensory and subcortical networks. Aging effects in these networks were stronger for long-range than for short-range FCD and were also detected at the level of the main functional hubs. Females had higher short- and long-range FCD in DMN and lower FCD in the somatosensory network than males, but the gender by age interaction effects were not significant for any of the networks or hubs. These findings suggest that long-range connections may be more vulnerable to aging effects than short-range connections and that, in addition to the DMN, the DAN is also sensitive to aging effects, which could underlie the deterioration of attention processes that occurs with aging.

  3. Magnetic Resonance Imaging (MRI) Safety

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does it ... and MRI Breast-feeding and MRI What is MRI and how does it work? Magnetic resonance imaging, ...

  4. Resonant photothermal IR spectroscopy of picogram samples with microstring resonator

    DEFF Research Database (Denmark)

    Yamada, Shoko; Schmid, Silvan; Boisen, Anja

    2013-01-01

    Here, we report a demonstration of resonant photothermal IR spectroscopy using microstrings in mid-infrared region providing rapid identification of picogram samples. In our microelectromechanical resonant photothermal IR spectroscopy system, samples are deposited directly on microstrings using...... an in-situ sampling method and the resonance frequency of the string is measured optically. Resonance frequency shifts, proportional to the absorbed heat, are recorded in real time as monochromatic infrared light is being scanned over the mid-infrared range. These resonant photothermal IR spectroscopy...

  5. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful ... of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  7. Characterizing coupled MEMS resonators with an electrical resonator

    Science.gov (United States)

    Tao, Guowei; Choubey, Bhaskar

    2016-10-01

    Rapid development in micro/nano fabrication has enabled the shrinking of MEMS devices and the ability to fabricate them in large arrays. However, process variations and device mismatch have also raised testability issues in the MEMS industry. MEMS resonators have been coupled to simplify the characterization of the fabrication process and device performance using their collective behaviour. Perturbation analysis using eigenvalues can therefore be applied to extract the system matrix of coupled resonators. We propose a new way of perturbation analysis by coupling an electrical resonator to an array of MEMS resonators. The electrical resonator is simple in structure and easy to readout. It can also precisely control the amount of perturbation based on two available techniques. Coupling between MEMS resonators and electrical resonator opens a new window for process characterization, device testing, material characterization, as well as large sensors array actuation.

  8. RESONANT CAVITY EXCITATION SYSTEM

    Science.gov (United States)

    Baker, W.R.; Kerns, Q.A.; Riedel, J.

    1959-01-13

    An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.

  9. Parallel Magnetic Resonance Imaging

    CERN Document Server

    Uecker, Martin

    2015-01-01

    The main disadvantage of Magnetic Resonance Imaging (MRI) are its long scan times and, in consequence, its sensitivity to motion. Exploiting the complementary information from multiple receive coils, parallel imaging is able to recover images from under-sampled k-space data and to accelerate the measurement. Because parallel magnetic resonance imaging can be used to accelerate basically any imaging sequence it has many important applications. Parallel imaging brought a fundamental shift in image reconstruction: Image reconstruction changed from a simple direct Fourier transform to the solution of an ill-conditioned inverse problem. This work gives an overview of image reconstruction from the perspective of inverse problems. After introducing basic concepts such as regularization, discretization, and iterative reconstruction, advanced topics are discussed including algorithms for auto-calibration, the connection to approximation theory, and the combination with compressed sensing.

  10. Resonant SIMP dark matter

    Directory of Open Access Journals (Sweden)

    Soo-Min Choi

    2016-07-01

    Full Text Available We consider a resonant SIMP dark matter in models with two singlet complex scalar fields charged under a local dark U(1D. After the U(1D is broken down to a Z5 discrete subgroup, the lighter scalar field becomes a SIMP dark matter which has the enhanced 3→2 annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic mixing between the SM hypercharge and dark gauge bosons can be used to make SIMP dark matter in kinetic equilibrium with the SM during freeze-out.

  11. Cross Resonant Optical Antenna

    Science.gov (United States)

    Biagioni, P.; Huang, J. S.; Duò, L.; Finazzi, M.; Hecht, B.

    2009-06-01

    We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter interactions based on polarized light as well as the analysis of polarized fields on the nanometer scale.

  12. Resonance Enhanced Tunneling

    CERN Document Server

    Matsumoto, S; Matsumoto, Sh.

    2000-01-01

    Time evolution of tunneling in thermal medium is examined using the real-time semiclassical formalism previously developed. Effect of anharmonic terms in the potential well is shown to give a new mechanism of resonance enhanced tunneling. If the friction from environment is small enough, this mechanism may give a very large enhancement for the tunneling rate. The case of the asymmetric wine bottle potential is worked out in detail.

  13. Cross resonant optical antenna.

    Science.gov (United States)

    Biagioni, P; Huang, J S; Duò, L; Finazzi, M; Hecht, B

    2009-06-26

    We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter interactions based on polarized light as well as the analysis of polarized fields on the nanometer scale.

  14. Injection-controlled laser resonator

    Science.gov (United States)

    Chang, J.J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

  15. Understanding aging.

    Science.gov (United States)

    Strehler, B L

    2000-01-01

    Enormous advances in our understanding of human aging have occurred during the last 50 yr. From the late 19th to the mid-20th centuries only four comprehensive and important sources of information were available: 1. August Weismann's book entitled Essays on Heredity and Kindred Biological Problems (the first of these essays dealt with The Duration of Life; 1). Weissmann states (p. 10) "In the first place in regulating the length of life, the advantage to the species, and not to the individual, is alone of any importance. This must be obvious to any one who has once thoroughly thought out the process of natural selection_". 2. A highly systematized second early source of information on aging was the collection of essays edited by Cowdry and published in 1938. This 900+ page volume contains 34 chapters and was appropriately called Problems of Aging. 3. At about the same time Raymond Pearl published his book on aging (2). Pearl believed that aging was the indirect result of cell specialization and that only the germ line was resistant to aging. Unfortunately Pearl died in the late 1930s and is largely remembered now for having been the founding editor of Quarterly Review of Biology while he was at the Johns Hopkins University, this author's alma mater. 4. Alexis Carrel wrote a monumental scientific and philosophical book, Man, the Unknown (3). Carrel believed that he had demonstrated that vertebrate cells could be kept in culture and live indefinitely, a conclusion challenged by others (more on this later).

  16. Persistence, resistance, resonance

    Science.gov (United States)

    Tsadka, Maayan

    Sound cannot travel in a vacuum, physically or socially. The ways in which sound operates are a result of acoustic properties, and the ways by which it is considered to be music are a result of social constructions. Therefore, music is always political, regardless of its content: the way it is performed and composed; the choice of instrumentation, notation, tuning; the medium of its distribution; its inherent hierarchy and power dynamics, and more. My compositional praxis makes me less interested in defining a relationship between music and politics than I am in erasing---or at least blurring---the borders between them. In this paper I discuss the aesthetics of resonance and echo in their metaphorical, physical, social, and musical manifestations. Also discussed is a political aesthetic of resonance, manifested through protest chants. I transcribe and analyze common protest chants from around the world, categorizing and unifying them as universal crowd-mobilizing rhythms. These ideas are explored musically in three pieces. Sumud: Rhetoric of Resistance in Three Movements, for two pianos and two percussion players, is a musical interpretation of the political/social concept of sumud, an Arabic word that literally means "steadfastness" and represents Palestinian non-violent resistance. The piece is based on common protest rhythms and uses the acoustic properties inherent to the instruments. The second piece, Three Piano Studies, extends some of the musical ideas and techniques used in Sumud, and explores the acoustic properties and resonance of the piano. The final set of pieces is part of my Critical Mess Music Project. These are site-specific musical works that attempt to blur the boundaries between audience, performers and composer, in part by including people without traditional musical training in the process of music making. These pieces use the natural structure and resonance of an environment, in this case, locations on the UCSC campus, and offer an active

  17. Parametric Resonance in Dynamical Systems

    CERN Document Server

    Nijmeijer, Henk

    2012-01-01

    Parametric Resonance in Dynamical Systems discusses the phenomenon of parametric resonance and its occurrence in mechanical systems,vehicles, motorcycles, aircraft and marine craft, and micro-electro-mechanical systems. The contributors provide an introduction to the root causes of this phenomenon and its mathematical equivalent, the Mathieu-Hill equation. Also included is a discussion of how parametric resonance occurs on ships and offshore systems and its frequency in mechanical and electrical systems. This book also: Presents the theory and principles behind parametric resonance Provides a unique collection of the different fields where parametric resonance appears including ships and offshore structures, automotive vehicles and mechanical systems Discusses ways to combat, cope with and prevent parametric resonance including passive design measures and active control methods Parametric Resonance in Dynamical Systems is ideal for researchers and mechanical engineers working in application fields such as MEM...

  18. The Comparative Study of Oral Resonance Acoustic Characteristics of School -Aged Children with Down Syndrome and Normal Children%学龄唐氏综合征患儿与正常儿童口腔共鸣声学特征比较

    Institute of Scientific and Technical Information of China (English)

    万勤; 努尔署瓦克; 邵国郡; 黄昭鸣

    2013-01-01

    Objective To compare the resonance acoustic characteristics between 7~16 years old Down syn-drome children and normal children .Methods A total of 29 cases of 7~16 years old Down syndrome children and 90 cases of 7~16 years old normal children pronuanced /a/,/u/,/i/,each sound for 3 times ,every time 1 to 2 sec-onds .The oral resonance acoustic parameters ,including F1 (a) ,F2 (a) ,F1 (i) ,F2 (i) ,F1 (u) ,F2 (u) ,the distance of tongue and the distance of jaw ,were recorded by real analysis .Analysis of variance was used for the voice acous-tic .Results With age ,there was a significant decrease tendency of the value of F2 (a) and a very significant growth tendency of the values of F2 (i) and the distance of tongue in normal children .The value of F2 (i) inrcreased signifi-cantly in Down syndrome children .The values of every oral resonance acoustic parameters were not different signifi-cantly on sex in normal children .The values of F1 (i) and F1 (u) in Down syndrome boys were significantly less than those of in the Down syndrome girls ,but the the distance of jaw in Down syndrome boys were significantly greater than those of in the Down syndrome girls .The values of F2 (u) and F1 (i) in Down syndrome children were signifi-cantly greater than those of in normal children ,but the distance of tongue was significantly less than those of in nor-mal children .Conclusion With age ,in normal children ,the amplitude of the tongue forward movement and the range of tongue back and forward movement were increased significantly ,the oral focus moved forward gradually .In Down syndrome children ,the amplitude of the tongue back movement ,and the range of tongue back and forward movement ,were poor than those of in normal children .The Down syndrome children were easier to suffer from oral resonance disorder than normal children .%目的探讨7~16岁唐氏综合征儿童与正常儿童口腔共鸣声学特征的差异。方法29例7~16岁唐氏综合征儿童和90例7~16

  19. Age Rules

    Science.gov (United States)

    Taylor, G. J.

    2015-10-01

    The ages of rocks from the lunar highlands vary widely, even for a single rock sample. This makes it difficult to quantitatively test ideas for early lunar differentiation and formation of the crust. Lars Borg and Amy Gaffney (Lawrence Livermore National Laboratory), and Charles Shearer (University of New Mexico) have devised a set of guidelines to apply to geochronological data that leads to a relative ranking of the reliability of the age determined for a sample. Applying their guidelines to existing data for lunar highland rocks shows an upper limit on rock ages between 4340 and 4370 million years. This is essentially the same as the so-called model ages of the formation of KREEP (a chemical component enriched in potassium, rare earth elements, and phosphorous) and of the formation of the deep source regions that melted to produce mare basalts. The numerous ages close to 4370 million years suggests a complicated and protracted cooling of the primordial lunar magma ocean or a widespread vigorous period of magmatic activity in the Moon.

  20. Successful ageing

    DEFF Research Database (Denmark)

    Bülow, Morten Hillgaard; Söderqvist, Thomas

    2014-01-01

    Since the late 1980s, the concept of ‘ successful ageing’ has set the frame for discourse about contemporary ageing research. Through an analysis of the reception to John W. Rowe and Robert L. Kahn's launch of the concept of ‘ successful ageing’ in 1987, this article maps out the important themes...... and discussions that have emerged from the interdisciplinary field of ageing research. These include an emphasis on interdisciplinarity; the interaction between biology, psycho-social contexts and lifestyle choices; the experiences of elderly people; life-course perspectives; optimisation and prevention...... strategies; and the importance of individual, societal and scientific conceptualisations and understandings of ageing. By presenting an account of the recent historical uses, interpretations and critiques of the concept, the article unfolds the practical and normative complexities of ‘ successful ageing’....

  1. Resonance frequency analysis

    Directory of Open Access Journals (Sweden)

    Rajiv K Gupta

    2011-01-01

    Full Text Available Initial stability at the placement and development of osseointegration are two major issues for implant survival. Implant stability is a mechanical phenomenon which is related to the local bone quality and quantity, type of implant, and placement technique used. The application of a simple, clinically applicable, non-invasive test to assess implant stability and osseointegration is considered highly desirable. Resonance frequency analysis (RFA is one of such techniques which is most frequently used now days. The aim of this paper was to review and analyze critically the current available literature in the field of RFA, and to also discuss based on scientific evidence, the prognostic value of RFA to detect implants at risk of failure. A search was made using the PubMed database to find all the literature published on "Resonance frequency analysis for implant stability" till date. Articles discussed in vivo or in vitro studies comparing RFA with other methods of implant stability measurement and articles discussing its reliability were thoroughly reviewed and discussed. A limited number of clinical reports were found. Various studies have demonstrated the feasibility and predictability of the technique. However, most of these articles are based on retrospective data or uncontrolled cases. Randomized, prospective, parallel-armed longitudinal human trials are based on short-term results and long-term follow up are still scarce in this field. Nonetheless, from available literature, it may be concluded that RFA technique evaluates implant stability as a function of stiffness of the implant bone interface and is influenced by factors such as bone type, exposed implant height above the alveolar crest. Resonance frequency analysis could serve as a non-invasive diagnostic tool for detecting the implant stability of dental implants during the healing stages and in subsequent routine follow up care after treatment. Future studies, preferably randomized

  2. Electroexcitation of nucleon resonances

    Energy Technology Data Exchange (ETDEWEB)

    Inna Aznauryan, Volker D. Burkert

    2012-01-01

    We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV2 for the Delta(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the Delta(1232) indicate large pion-cloud contributions at low Q2 and don't show any sign of approaching the pQCD regime for Q2<7 GeV2. Measured for the first time, the electroexcitation amplitudes of the Roper resonance, N(1440)P11, provide strong evidence for this state as a predominantly radial excitation of a three-quark (3q) ground state, with additional non-3-quark contributions needed to describe the low Q2 behavior of the amplitudes. The longitudinal transition amplitude for the N(1535)S11 was determined and has become a challenge for quark models. Explanations may require large meson-cloud contributions or alternative representations of this state. The N(1520)D13 clearly shows the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q2 > 0.5 GeV2, confirming a long-standing prediction of the constituent quark model. The interpretation of the moments of resonance transition form factors in terms of transition transverse charge distributions in infinite momentum frame is presented.

  3. Resonance frequency in ferromagnetic superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Rongke; Huang Andong [School of Science, Shenyang University of Technology, Shenyang 110870 (China); Li Da; Zhang Zhidong, E-mail: rkqiu@163.com [Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang 110016 (China)

    2011-10-19

    The resonance frequency in two-layer and three-layer ferromagnetic superlattices is studied, using the Callen's Green function method, the Tyablikov decoupling approximation and the Anderson-Callen decoupling approximation. The effects of interlayer exchange coupling, anisotropy, external magnetic field and temperature on the resonance frequency are investigated. It is found that the resonance frequencies increase with increasing external magnetic field. In a parameter region of the asymmetric system, each sublayer corresponds to its own resonance frequency. The anisotropy of a sublayer affects only the resonance frequency corresponding to this sublayer. The stronger the anisotropy, the higher is the resonance frequency. The interlayer exchange coupling affects only the resonance frequencies belonging to the sublayers connected by it. The stronger the interlayer exchange coupling, the higher are the resonance frequencies. All the resonance frequencies decrease as the reduced temperature increases. The results direct the method to enhance and adjust the resonance frequency of magnetic multilayered materials with a wide band.

  4. Search for resonant $\\widetilde\

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Bugge, L; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F R; Chapkin, M M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crawley, B; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L S; Di Ciaccio, Lucia; Di Simone, A; Doroba, K; Drees, J; Dris, M; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, Michael; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J A; Gandelman, M; García, C; Gavillet, P; Gazis, E N; Geralis, T; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Hansen, J; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E C; Kernel, G; Kersevan, Borut P; Kiiskinen, A P; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Meyer, W T; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L M; Murray, W; Muryn, B; Myatt, Gerald; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Pukhaeva, N; Pullia, Antonio; Rames, J; Ramler, L; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Rosenberg, E I; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sissakian, A N; Smadja, G; Smirnova, O G; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L G; Tobin, M; Todorovova, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vegni, G; Veloso, F; Venus, W A; Verbeure, F; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zimin, N I; Zinchenko, A I; Zupan, M

    2003-01-01

    Searches for resonant ~nu production in e+e collisions under the assumption that R-parity is not conserved and that the dominant R-parity violating coupling is lambda121 or lambda131 used data recorded by DELPHI in 1997 to 2000 at centre-of-mass energies of 183 to 208 GeV. No deviation from the Standard Model was obs erved. Upper limits are given for the lambda121 and lamdba131 couplings as a function of the sneutrino mass and total width. The limits are especially stringent for sneutrino masses equal to the centre-of-mass energies with the highest integrated luminosities recorded.

  5. Nanotube resonator devices

    Science.gov (United States)

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  6. General resonance mediation

    Energy Technology Data Exchange (ETDEWEB)

    McGarrie, Moritz

    2012-07-15

    We extend the framework of general gauge mediation to cases where the mediating fields have a nontrivial spectral function, as might arise from strong dynamics. We demonstrate through examples that this setup describes a broad class of possible models of gauge mediated supersymmetry breaking. A main emphasis is to give general formulas for cross sections for {sigma}(visible {yields} hidden) in these resonance models. We will also give formulas for soft masses, A-terms and demonstrate the framework with a holographic setup.

  7. Resonance test system

    Science.gov (United States)

    Musial, Walter [Boulder, CO; White, Darris [Superior, CO

    2011-05-31

    An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

  8. Fast Resonance Frequency Modulation in Superconducting Stripline Resonator

    OpenAIRE

    Segev, Eran; Abdo, Baleegh; Shtempluck, Oleg; Buks, Eyal

    2006-01-01

    Fast resonance frequency modulation of a superconducting stripline resonator is investigated. The experiments are performed using a novel device which integrates a hot electron detector (HED) into a superconducting stripline ring resonator. Frequency modulation is demonstrated by both applying dc current or voltage to the HED, and by applying optical illumination, with modulation frequencies of up to 4.2GHz. Potential applications for such a device are in telecommunication, quantum cryptograp...

  9. Neuroimaging of pediatric brain tumors: from basic to advanced magnetic resonance imaging (MRI).

    Science.gov (United States)

    Panigrahy, Ashok; Blüml, Stefan

    2009-11-01

    In this review, the basic magnetic resonance concepts used in the imaging approach of a pediatric brain tumor are described with respect to different factors including understanding the significance of the patient's age. Also discussed are other factors directly related to the magnetic resonance scan itself including evaluating the location of the tumor, determining if the lesion is extra-axial or intra-axial, and evaluating the contrast characteristics of the lesion. Of note, there are key imaging features of pediatric brain tumors, which can give information about the cellularity of the lesion, which can then be confirmed with advanced magnetic resonance imaging (MRI) techniques. The second part of this review will provide an overview of the major advanced MRI techniques used in pediatric imaging, particularly, magnetic resonance diffusion, magnetic resonance spectroscopy, and magnetic resonance perfusion. The last part of the review will provide more specific information about the use of advanced magnetic resonance techniques in the evaluation of pediatric brain tumors.

  10. Miniaturised self-resonant split-ring resonator antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    A self-resonant miniaturized antenna composed of a broadside-coupled split-ring resonator (SRR) and an excitation arc-shaped monopole is presented. The size of the antenna and its resonance frequency is essentially defined by the SRR dimensions and geometry, while the input resistance...... at the resonance is governed by the arc length of the monopole. Numerical and experimental results are presented for an antenna configuration of 1/23.4 wavelength in diameter (ka~0.134). The antenna is tuned to 50 ohms without any matching network, and its efficiency is measured to be 17.5%....

  11. Cyclotron resonant interactions in cosmic particle accelerators

    CERN Document Server

    Terasawa, T; 10.1007/s11214-012-9878-0

    2012-01-01

    A review is given for cyclotron resonant interactions in space plasmas. After giving a simple formulation for the test particle approach, illustrative examples for resonant interactions are given. It is shown that for obliquely propagating whistler waves, not only fundamental cyclotron resonance, but also other resonances, such as transit-time resonance, anomalous cyclotron resonance, higher-harmonic cyclotron resonance, and even subharmonic resonance can come into play. A few recent topics of cyclotron resonant interactions, such as electron injection in shocks, cyclotron resonant heating of solar wind heavy ions, and relativistic modifications, are also reviewed.

  12. Cranial magnetic resonance imaging in chronic demyelinating polyneuropathy.

    OpenAIRE

    Hawke, S H; Hallinan, J M; McLeod, J G

    1990-01-01

    Twenty one patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and five patients with chronic demyelinating polyneuropathy associated with benign monoclonal paraproteinaemia none of whom had signs or symptoms of central nervous system disease, had cranial magnetic resonance imaging (MRI) on a 1.5 Tesla unit. Areas of increased white matter signal intensity were seen in one of 10 patients aged less than 50 years and in five of 16 patients aged more than 50 years. In ...

  13. Aging perspectives

    NARCIS (Netherlands)

    Cosco, T.D.; Brehme, D.; Grigoruta, N.; Kaufmann, L.K.; Lemsalu, L.; Meex, R.C.R.; Schuurmans, A.T.; Sener, N.

    2014-01-01

    Despite the proliferation of successful ageing (SA) research, the literature is dominated by researcher-driven Anglophone conceptualisations. To date, lay perspectives of SA have not been examined in Europe or Turkey. The current study aims to conduct a mixed-methods examination of conceptualisation

  14. Aging Secret

    Science.gov (United States)

    Journal of College Science Teaching, 2005

    2005-01-01

    The canny world of advertising has caught on to the free radical theory of aging, marketing a whole array of antioxidants for preventing anything from wrinkles to dry hair to reducing the risk of heart disease--promising to help slow the hands of time. Working with genetically engineered mice--to produce a natural antioxidant enzyme called…

  15. Gay aging.

    Science.gov (United States)

    Haber, David

    2009-01-01

    The oldest of the baby boomers (boomers) were age 63 in 2009 and on the verge of retirement. This cohort has had a history of making societal changes throughout its life cycle, and it is unlikely that retirement, as we know it, will remain unscathed. This article highlights two events-the Stonewall Inn riots and two prominent professional associations removing homosexuality from their list of personality disorders-and how they occurred early enough in the gay boomers life cycle to change their attitudes, behaviors, and lifestyles. This article introduces the reader to a broad array of facts, research findings, and issues that inform the topic of gay aging. A summary of the discrimination and legal concerns affecting the gay community are also highlighted. Two influential community programs are identified: Services and Advocacy for Gay Elders (SAGE) and the American Society on Aging's LGBT Aging Issues Network (LAIN). Gerontological educators need to be sensitive to the needs, desires, and resources of the coming cohort of gay boomers, who are more likely to advocate for responsive services, organizations, and policies than the current cohort of gay older adults.

  16. Successful ageing

    DEFF Research Database (Denmark)

    Kusumastuti, Sasmita; Derks, Marloes G. M.; Tellier, Siri;

    2016-01-01

    . METHODS: We performed a novel, hypothesis-free and quantitative analysis of citation networks exploring the literature on successful ageing that exists in the Web of Science Core Collection Database using the CitNetExplorer software. Outcomes were visualized using timeline-based citation patterns...

  17. Nuclear Magnetic Resonance Gyroscope

    Science.gov (United States)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  18. Electroexcitation of nucleon resonances

    CERN Document Server

    Aznauryan, I G

    2011-01-01

    We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV2 for the Delta(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13}, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the Delta(1232) indicate large pion-cloud contributions at low Q2 and don't show any sign of approaching the pQCD regime for Q2 0.5 GeV2, confirming a long-standing prediction of the constituent quark model. The interpretation of the moments of resonance transition form factors in terms of transition transverse charge distributions in infinite momentum frame is presented.

  19. Fermi resonance in optical microcavities

    Science.gov (United States)

    Yi, Chang-Hwan; Yu, Hyeon-Hye; Lee, Ji-Won; Kim, Chil-Min

    2015-04-01

    Fermi resonance is a phenomenon of quantum mechanical superposition, which most often occurs between normal and overtone modes in molecular systems that are nearly coincident in energy. We find that scarred resonances in deformed dielectric microcavities are the very phenomenon of Fermi resonance, that is, a pair of quasinormal modes interact with each other due to coupling and a pair of resonances are generated through an avoided resonance crossing. Then the quantum number difference of a pair of quasinormal modes, which is a consequence of quantum mechanical superposition, equals periodic orbits, whereby the resonances are localized on the periodic orbits. We derive the relation between the quantum number difference and the periodic orbits and confirm it in an elliptic, a rectangular, and a stadium-shaped dielectric microcavity.

  20. DISSIPATIVE DIVERGENCE OF RESONANT ORBITS

    Energy Technology Data Exchange (ETDEWEB)

    Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Morbidelli, Alessandro, E-mail: kbatygin@gps.caltech.edu [Departement Cassiopee, Universite de Nice-Sophia Antipolis, Observatoire de la Cote d' Azur, F-06304 Nice (France)

    2013-01-01

    A considerable fraction of multi-planet systems discovered by the observational surveys of extrasolar planets reside in mild proximity to first-order mean-motion resonances. However, the relative remoteness of such systems from nominal resonant period ratios (e.g., 2:1, 3:2, and 4:3) has been interpreted as evidence for lack of resonant interactions. Here, we show that a slow divergence away from exact commensurability is a natural outcome of dissipative evolution and demonstrate that libration of critical angles can be maintained tens of percent away from nominal resonance. We construct an analytical theory for the long-term dynamical evolution of dissipated resonant planetary pairs and confirm our calculations numerically. Collectively, our results suggest that a significant fraction of the near-commensurate extrasolar planets are in fact resonant and have undergone significant dissipative evolution.

  1. Dissipative Divergence of Resonant Orbits

    CERN Document Server

    Batygin, Konstantin

    2012-01-01

    A considerable fraction of multi-planet systems discovered by the observational surveys of extrasolar planets reside in mild proximity to first-order mean motion resonances. However, the relative remoteness of such systems from nominal resonant period ratios (e.g. 2:1, 3:2, 4:3) has been interpreted as evidence for lack of resonant interactions. Here we show that a slow divergence away from exact commensurability is a natural outcome of dissipative evolution and demonstrate that libration of critical angles can be maintained tens of percent away from nominal resonance. We construct an analytical theory for the long-term dynamical evolution of dissipated resonant planetary pairs and confirm our calculations numerically. Collectively, our results suggest that a significant fraction of the near-commensurate extrasolar planets are in fact resonant and have undergone significant dissipative evolution.

  2. Precession resonance in water waves

    CERN Document Server

    Lucas, Dan; Perlin, Marc

    2016-01-01

    We describe the theory and present numerical evidence for a new type of nonlinear resonant interaction between gravity waves on the surface of deep water. The resonance constitutes a generalisation of the usual 'exact' resonance as we show that exchanges of energy between the waves can be enhanced when the interaction is three-wave rather than four and the linear frequency mismatch, or detuning, is non-zero i.e. $\\omega_1\\pm\\omega_2\\pm\\omega_3 \

  3. Advances in magnetic resonance 11

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 11, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters and begins with a discussion of the principles and applications of dynamic nuclear polarization, with emphasis on molecular motions and collisions, intermolecular couplings, and chemical interactions. Subsequent chapters focus on the assessment of a proposed broadband decoupling method and studies of time-domain (or Fourier transform) multiple-quantum nuclear magnetic resonance.

  4. Efficient primary and parametric resonance excitation of bistable resonators

    KAUST Repository

    Ramini, Abdallah

    2016-09-12

    We experimentally demonstrate an efficient approach to excite primary and parametric (up to the 4th) resonance of Microelectromechanical system MEMS arch resonators with large vibrational amplitudes. A single crystal silicon in-plane arch microbeam is fabricated such that it can be excited axially from one of its ends by a parallel-plate electrode. Its micro/nano scale vibrations are transduced using a high speed camera. Through the parallel-plate electrode, a time varying electrostatic force is applied, which is converted into a time varying axial force that modulates dynamically the stiffness of the arch resonator. Due to the initial curvature of the structure, not only parametric excitation is induced, but also primary resonance. Experimental investigation is conducted comparing the response of the arch near primary resonance using the axial excitation to that of a classical parallel-plate actuation where the arch itself forms an electrode. The results show that the axial excitation can be more efficient and requires less power for primary resonance excitation. Moreover, unlike the classical method where the structure is vulnerable to the dynamic pull-in instability, the axial excitation technique can provide large amplitude motion while protecting the structure from pull-in. In addition to primary resonance, parametrical resonances are demonstrated at twice, one-half, and two-thirds the primary resonance frequency. The ability to actuate primary and/or parametric resonances can serve various applications, such as for resonator based logic and memory devices. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

  5. Electromagnetic production of hyperon resonances

    Energy Technology Data Exchange (ETDEWEB)

    K. Hicks, D. Keller, W. Tang

    2011-10-01

    The study of hyperon resonances has entered a new era of precision with advent of high-statistics photoproduction data from the CLAS detector at Jefferson Lab. These data have multi-particle final states, allowing clean identification of exclusive reactions associated with strange mesons and baryons. Examples of physics results are: evidence for isospin interference in the decay of the {Lambda}(1405) resonance; a strong suggestion of meson cloud effects in the structure of the {Sigma}(1385) resonance; data from K* photoproduction that will test the existence of the purported K{sub 0}(800)$ meson. Properties of other hyperon resonances will also be studied in the near future.

  6. Advances in magnetic resonance 12

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 12, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains six chapters and begins with a discussion of diffusion and self-diffusion measurements by nuclear magnetic resonance. This is followed by separate chapters on spin-lattice relaxation time in hydrogen isotope mixtures; the principles of optical detection of nuclear spin alignment and nuclear quadropole resonance; and the spin-1 behavior, including the relaxation of the quasi-invariants of the motion of a system of pairs of dipolar coupled spin-1/2 nu

  7. Orbital resonances around black holes.

    Science.gov (United States)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  8. Theory of Adiabatic Fountain Resonance

    Science.gov (United States)

    Williams, Gary A.

    2017-01-01

    The theory of "Adiabatic Fountain Resonance" with superfluid ^4{He} is clarified. In this geometry a film region between two silicon wafers bonded at their outer edge opens up to a central region with a free surface. We find that the resonance in this system is not a Helmholtz resonance as claimed by Gasparini et al., but in fact is a fourth sound resonance. We postulate that it occurs at relatively low frequency because the thin silicon wafers flex appreciably from the pressure oscillations of the sound wave.

  9. Frequency Resonance in Stochastic Systems

    Institute of Scientific and Technical Information of China (English)

    钱敏; 张雪娟

    2003-01-01

    The phenomenon of frequency resonance, which is usually related to deterministic systems, is investigated in stochastic systems. We show that for those autonomous systems driven only by white noise, if the output power spectrum exhibits a nonzero peak frequency, then applying a periodic signel just on this noise-induced central frequency can also induce a resonance phenomenon, which we call the frequency stochastic resonance. The effect of such a resonance in a coupled stochastic system is shown to be much better than that in a single-oscillator system.

  10. Advances in magnetic resonance 6

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 6 focuses on the theoretical and practical aspects of applying magnetic resonance methods to various problems in physical chemistry, emphasizing the different aspects of the exegesis of these problems. This book discusses the gas phase magnetic resonance of electronically excited molecules; techniques for observing excited electronic states; NMR studies in liquids at high pressure; and effect of pressure on self-diffusion in liquids. The nuclear magnetic resonance investigations of organic free radicals; measurement of proton coupling constants by NMR; an

  11. Novel resonant cantilever mass change detection and resonant frequency tuning

    DEFF Research Database (Denmark)

    Grigorov, Alexander; Boisen, Anja

    2005-01-01

    This paper reports a novel way to detect the resonant frequency of an electro-thermally actuated cantilever sensor that we have previously reported, in order to perform mass detection by resonant frequency shift detection. The device is based on monitoring the rupture of a clamped cantilever stru...

  12. Nonlinear Oscillations of Microscale Piezoelectric Resonators and Resonator Arrays

    Science.gov (United States)

    2006-06-30

    static buckling deflection of the resonator d3E, kI(x) d 3 , k(x) can be expressed as Elt -t = Elk ----- T- at X = Xk-_ Here, it is important to note that...a number of the parameters can resonators clearly reveal nonlinear characteristics. Although b icted by usng the ro rg met ersal the dimensions of

  13. Aging Avalanches

    Science.gov (United States)

    Boettcher, Stefan; Paczuski, Maya

    1997-03-01

    We have shown that in an analytically solvable model of Self-Organized Criticality (SOC)(S. Boettcher & M. Paczuski, Phys. Rev. Lett. 76), 348 (1996). the evolving avalanche is governed by an equation of motion with a memory term that ranges over all past events.(S. Boettcher & M. Paczuski, Phys. Rev. E 54), 1082 (1996). The solution for the propagator shows sub-diffusive behavior with a broad exponential tail. Numerical studies of the temporal correlations during avalanches in a variety of SOC systems indicate that history dependence and hierarchical structures are generic features which emerge dynamically from simple local update rules. In particular, we find(S. Boettcher & M. Paczuski, ``Off-Equilibrium Behavior and Aging in Self-Organized Criticality'', (in preparation).) ``aging'' similar to the slow relaxation behavior in disordered systems that move through ``rugged landscapes'' in phase space, such as spin glasses.

  14. Golden Age

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      Sometimes, a moment can announce the end of an age. The gold market is like that. Within two transaction days, the gold slumped by 13%and saw a 25%tumble from the high point in August 2011. According to the classic investment theory, a 20%-above decline means the shift from“a bull”to“a bear”market.   The super bear market of gold has lasted a dozen years. But the bull-to-bear shift was completed within only 20 minutes. Wall Street’s analysts and ordinary Chinese people had different understandings to the golden age.   Expecting a bear market, Wall Street continuously dumped gold, resulting in a diving of gold price. Seeing the benefits, leisure Chinese madams made a gold rush, causing a slight bounce of gold price. On April 23, renowned investment bank Goldman Sachs suspended the short sale. So,“Chinese aunts”beating back Wall Street’s analysts became the hottest topic online for the time being.   What are the decisive factors for the crash of gold price? Will the gold market complete a real bull-to-bear shift? Will the golden age of gold be farther or nearer?

  15. Geometrically Protected Resonance Modes and Optical Fano Resonances

    CERN Document Server

    Regan, Emma C; Lopez, Josue J; Hsu, Chia Wei; Zhen, Bo; Joannopoulos, John D; Soljacic, Marin

    2015-01-01

    Traditionally, photonic crystal slabs can support resonances that are strongly confined to the slab but also couple to external radiation. However, when a photonic crystal slab is placed on a substrate, the resonance modes become less confined, and as the index contrast between slab and substrate decreases, they eventually disappear. Using the scale structure of the Dione Juno butterfly wing as an inspiration, we present a low-index zigzag surface structure that supports resonance modes even without index contrast with the substrate. The zigzag structure supports resonances that are contained away from the substrate; this geometrically protects the modes from coupling to the substrate. We experimentally verify the protected resonance property of the zigzag structure in the visible wavelength regime. Potential applications include substrate-independent structural color and light guiding.

  16. Slope tunable Fano resonances in asymmetric embedded microring resonators

    Science.gov (United States)

    Wang, Gencheng; Dai, Tingge; Jiang, Jianfei; Yu, Hui; Hao, Yinlei; Wang, Yuehai; Li, Yubo; Jiang, Xiaoqing; Yang, Jianyi

    2017-02-01

    An asymmetric embedded microring resonant system is proposed and fabricated on a silicon-on-insulator (SOI) to achieve slope tunable Fano resonances. The Fano resonances originate from the nonlinear phase shift produced by adding an inner ring coupling with the outer ring. The slope of the Fano resonance can be well tuned to be ultra-high by controlling the microheaters to adjust the phase condition. Experimentally, we observe Fano resonance with a maximum extinction ratio of about 40 dB, and the slope can be tuned from -35 dB nm-1 to -93 dB nm-1, which shows good agreement with the theoretical analysis. This device could find potential applications in ultra-high sensitivity sensing systems.

  17. Resonant algebras and gravity

    CERN Document Server

    Durka, R

    2016-01-01

    We explore the $S$-expansion framework to analyze freedom in closing the multiplication tables for the abelian semigroups. Including possibility of the zero element in the resonant decomposition and relating the Lorentz generator with the semigroup identity element leads to the wide class of the expanded Lie algebras introducing interesting modifications to the gauge gravity theories. Among the results we find not only all the Maxwell algebras of type $\\mathfrak{B}_m$, $\\mathfrak{C}_m$, and recently introduced $\\mathfrak{D}_m$, but we also produce new examples. We discuss some prospects concerning further enlarging the algebras and provide all necessary constituents for constructing the gravity actions based on the obtained results.

  18. Resonant algebras and gravity

    Science.gov (United States)

    Durka, R.

    2017-04-01

    The S-expansion framework is analyzed in the context of a freedom in closing the multiplication tables for the abelian semigroups. Including the possibility of the zero element in the resonant decomposition, and associating the Lorentz generator with the semigroup identity element, leads to a wide class of the expanded Lie algebras introducing interesting modifications to the gauge gravity theories. Among the results, we find all the Maxwell algebras of type {{B}m} , {{C}m} , and the recently introduced {{D}m} . The additional new examples complete the resulting generalization of the bosonic enlargements for an arbitrary number of the Lorentz-like and translational-like generators. Some further prospects concerning enlarging the algebras are discussed, along with providing all the necessary constituents for constructing the gravity actions based on the obtained results.

  19. Hadron Resonances from QCD

    Energy Technology Data Exchange (ETDEWEB)

    Dudek, Jozef [Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-03-01

    I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study ππ elastic scattering, including the ρ resonance, as well as coupled-channel πK, ηK scattering. The very recent extension to the case where an external current acts is also presented, considering the reaction πγ* → ππ, from which the unstable ρ → πγ transition form factor is extracted. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.

  20. Resonant and rolling droplet

    CERN Document Server

    Dorbolo, S; Vandewalle, N; Gilet, T

    2008-01-01

    When an oil droplet is placed on a quiescent oil bath, it eventually collapses into the bath due to gravity. The resulting coalescence may be eliminated when the bath is vertically vibrated. The droplet bounces periodically on the bath, and the air layer between the droplet and the bath is replenished at each bounce. This sustained bouncing motion is achieved when the forcing acceleration is higher than a threshold value. When the droplet has a sufficiently low viscosity, it significantly deforms : spherical harmonic \\boldmath{$Y_{\\ell}^m$} modes are excited, resulting in resonant effects on the threshold acceleration curve. Indeed, a lower acceleration is needed when $\\ell$ modes with $m=0$ are excited. Modes $m \

  1. Resonant High Power Combiners

    CERN Document Server

    Langlois, Michel; Peillex-Delphe, Guy

    2005-01-01

    Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.

  2. Subinertial canyon resonance

    Science.gov (United States)

    Clarke, Allan J.; Van Gorder, Stephen

    2016-04-01

    Near the bottom of a narrow canyon currents that oscillate back and forth along the bottom slope hx in a stratified ocean of buoyancy frequency N do so with a natural internal gravitational frequency Nhx. From May 2012 to May 2013 Acoustic Doppler Current Profiler measurements were made at 715 m depth in the deep narrow part of the DeSoto Canyon south of Pensacola, Florida, in water with 2π/Nhx ≈ 2.5 days. Above the canyon the flow follows the large-scale isobaths, but beneath the canyon rim the current oscillates along the canyon axis with 2-3 day periodicity, and is much stronger than and uncorrelated with the overlying flow. A simple theoretical model explains the resonant response. Published observations from the Hudson and Gully canyons suggest that the strong subinertial current oscillations observed in these canyons occur close to the relevant local frequency Nhx, consistent with the proposed simple model physics.

  3. MRI (Magnetic Resonance Imager)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoshinori [Toshiba Corp., Kawasaki, Kanagawa (Japan)

    1995-05-01

    MRI is a widely used diagnostic imaging modality because it has excellent diagnostic capabilities, is safe to use and generates images not affected by bone artifacts. Images are obtained by utilizing the phenomenon of Nuclear Magnetic Resonance (NMR) by which protons located in a static magnetic field absorb radio frequency (RF) pulses with a specific frequency and release a part of the energy as a NMR signal. Potentially MRI has the ability to provide functional and metabolic information (such as flow, temperature, diffusion, neuron activity) in addition to morphological information. This paper describes the imaging principles and provides a general outline of some applications: flow imaging, metabolite imaging and temperature imaging. (J.P.N.).

  4. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  5. Baryon Spectroscopy and Resonances

    Energy Technology Data Exchange (ETDEWEB)

    Robert Edwards

    2011-12-01

    A short review of current efforts to determine the highly excited state spectrum of QCD, and in particular baryons, using lattice QCD techniques is presented. The determination of the highly excited spectrum of QCD is a major theoretical and experimental challenge. The experimental investigation of the excited baryon spectrum has been a long-standing element of the hadronic-physics program, an important component of which is the search for so-called 'missing resonances', baryonic states predicted by the quark model based on three constituent quarks but which have not yet been observed experimentally. Should such states not be found, it may indicate that the baryon spectrum can be modeled with fewer effective degrees of freedom, such as in quark-diquark models. In the past decade, there has been an extensive program to collect data on electromagnetic production of one and two mesons at Jefferson Lab, MIT-Bates, LEGS, MAMI, ELSA, and GRAAL. To analyze these data, and thereby refine our knowledge of the baryon spectrum, a variety of physics analysis models have been developed at Bonn, George Washington University, Jefferson Laboratory and Mainz. To provide a theoretical determination and interpretation of the spectrum, ab initio computations within lattice QCD have been used. Historically, the calculation of the masses of the lowest-lying states, for both baryons and mesons, has been a benchmark calculation of this discretized, finite-volume computational approach, where the aim is well-understood control over the various systematic errors that enter into a calculation; for a recent review. However, there is now increasing effort aimed at calculating the excited states of the theory, with several groups presenting investigations of the low-lying excited baryon spectrum, using a variety of discretizations, numbers of quark flavors, interpolating operators, and fitting methodologies. Some aspects of these calculations remain unresolved and are the subject of

  6. Estimation of the amount of telomere molecules in different human age groups and the telomere increasing effect of acupuncture and shiatsu on St.36, using synthesized basic units of the human telomere molecules as reference control substances for the bi-digital O-ring test resonance phenomenon.

    Science.gov (United States)

    Omura, Y; Shimotsura, Y; Ooki, M; Noguchi, T

    1998-01-01

    It is well established that the telomeres at the ends of chromosomes are composed of long arrays of (TTAGGG)n x (CCCTAA)n that form a nucleoprotein complex required for the replication and protection of chromosome ends. Throughout the cell cycle, telomeres also contain a protein component related to the proto-oncogene Myb that is known as TRF1 (telomere TTAGGG repeat binding factor 1) that binds to the duplex array of TTAGGG repeats in the telomere. Previous studies have shown that TRF1 appears to play a role in controlling the length of telomeres by acting as an inhibitor of telomerase. The amount of each of the TRF1(C-19) & TRF1(N-19) was identical to the amount of telomere of the same organ of the same apparently normal individual. Using synthesized basic unit of TTAGGG, as well as CCCTAA, as separate reference control substances for the Bi-Digital O-Ring Test of Resonance Phenomenon between 2 identical substances, we were able to non-invasively measure the approximate amount of TTAGGG and CCCTAA units, in both normal and cancerous human cells. We examined about 30 apparently normal subjects (both Asian and Caucasian in both sex). The subjects' ages ranged from infancy to 76 years. Each subject was first examined using TTAGGG as a control substance and then examined using CCCTAA as a control substance. The amount of telomere in various cancer tissues are almost always higher than that of normal tissue of the same organ. The measured amounts of both TTAGGG and CCCTAA were found to be in an average of 1500-1600 ng for human fetus or infancy and decreased with the advance of age in both sex with the exception of the heart, brain, eyes (retina), testes, and ovaries, which usually remain at the level of the infant, or reduced very little. Individuals in the same age group had a similar range of amounts of both TTAGGG and CCCTAA in the same organ of the same individual, (except for those with unusually low telomeres often had chronic degenerative diseases, and those

  7. Multiphonon giant resonances in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    1998-07-01

    We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)

  8. The Resonance of Renaissance Poetry.

    Science.gov (United States)

    Greenblatt, Stephen

    1980-01-01

    Discusses reading and teaching Renaissance poetry in terms of the poem's "resonance," its capacity to speak to contemporary readers directly and draw them into its historical world. Advises teachers to expand the resonance to illuminate the poem's background, as exemplified by the poetry of Thomas Wyatt in the court of Henry VIII. (DF)

  9. Color confinement multi quark resonance

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fan [Department of Physics, Nanjing University, Joint Center for Particle Nuclear Physics and Cosmology, Nanjing University and Pupil Mountain Observatory, Nanjing, 210008 (China); Ping, J.L. [Department of Physics, Nanjing Normal University, Nanjing, 210097 (China); Pang, H.R. [Department of Physics, Southeast University, Nanjing, 210008 (China); Chen, L.Z. [Department of Physics, Nanjing University, Joint Center for Particle Nuclear Physics and Cosmology, Nanjing University and Pupil Mountain Observatory, Nanjing, 210008 (China)

    2007-06-15

    A new kind microscopic resonance, the color confinement multi quark resonance is proposed and studied. The quark delocalization color screening model is compared to one of the chiral quark model, the Salamanca model, and a new mechanism of the intermediate range NN interaction, the mutual distortion of interacting nucleons, is checked to be similar to the {sigma} meson exchange.

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  11. Integrated silicon optofluidic ring resonator

    NARCIS (Netherlands)

    Testa, G.; Huang, Y.; Sarro, P.M.; Zeni, L.; Bernini, R.

    2010-01-01

    The feasibility of an integrated silicon optofluidic ring resonator is demonstrated. Liquid core antiresonant reflecting optical waveguides are used to realize a rectangular ring resonator with a multimode interference liquid core coupler between the ring and the bus waveguide. In this configuration

  12. Aging Perspectives

    Directory of Open Access Journals (Sweden)

    Theodore D Cosco

    2014-05-01

    Full Text Available Despite the proliferation of successful ageing (SA research, the literature is dominated by researcher-driven Anglophone conceptualisations. To date, lay perspectives of SA have not been examined in Europe or Turkey. The current study aims to conduct a mixed-methods examination of conceptualisations of SA in seven underrepresented countries. Using snowball sampling via social media sites, an online survey consisting of established closed-ended and open-ended items – translated into seven languages – was administered. Grounded theory methods and descriptive statistics were used to analyse qualitative and quantitative data, respectively.

  13. Aging Blepharoplasty

    Directory of Open Access Journals (Sweden)

    Inchang Cho

    2013-09-01

    Full Text Available In performing upper blepharoplasty in the elderly, looking younger and keeping the eyelidsharmonious with the rest of the face have to be achieved at the same time. The most importantgoal in upper blepharoplasty for aging is correcting the drooping upper eyelid skin, and inthis process, the surgeon may or may not create a double eyelid fold. The pros and cons haveto be fully discussed with the patient, but the author personally prefers creating a doublefold unless the patient refuses, because it is efficient in correcting and preventing furtherdrooping of the skin. In most patients, the brow is elevated to compensate for the droopingeyelid, and when the drooping is corrected, brow ptosis may ensue. The surgeon has to preparefor these consequences before performing the procedure, and estimate the exact amountof skin to be excised. In the elderly, the skin and the orbicularis oculi muscle is thin, with adecreased amount of subcutaneous fat and retro-orbicularis oculi fat, and in most cases,excision of the skin alone is enough to correct the deformity. Removing large portions ofsoft tissue may also prolong the recovery period. Unlike younger patients, the lower skinflap should not be stretched too much in the elderly, as it may create an aggressive lookingappearance. A few wrinkles in the lower flap should remain untouched to create a naturallook. In this article, the author’s own methods of performing an aging blepharoplasty aredescribed specifically, with a step-by-step guide and surgical tips.

  14. Magnetic resonance imaging of cystic periventricular leukomalacia

    Energy Technology Data Exchange (ETDEWEB)

    Kadoi, Nobuaki; Nomura, Junko; Nowatari, Masahiko; Ohta, Takeo; Kamohara, Takashi; Yashiro, Kimio (Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Medicine)

    1990-08-01

    A study was performed to assess the values of magnetic resonance (MR) imaging in evaluation and the follow up of patients with cystic periventricular leukomalacia. Ten patients selected for MR imaging were diagnosed as having periventricular cystic lesions based on US scans. The range of gestational ages was 27 to 32 weeks, and the range of birth weights was 927 to 2,046 g. Twenty MR examinations were carried out using a 0.5 T superconducting system (Resona; Yokogawa). On the first MR examinations, taken by 6 months of age, low signal intensity lesions within the periventricular white matter, moderate ventriculomegaly with irregularity of the ventricular wall and delayed myelination were observed. These were the MR findings observed in the subacute stage of PVL. On the second or the third MR examinations, taken after 12 months of age, increased signal intensity in periventricular white matter on T{sub 2} weighted images decreased volume of periventricular white matter and centrum semiovale and the ventriculomagaly with irregularity of ventricular wall were observed. However, progressions of myelination were proved to be not delayed in comparison with age matched controls. These were thought to be the MR findings of late stage of PVL. As the US findings of PVL have good correlation with pathologic changes revealed at autopsy, MR imaging can depict myelination and detect PVL lesion beyond the neonatal period. These observations demonstrate the value of the MR imaging for the follow up of the patients with PVL beyond the time of fontanel closure. (author).

  15. Nucleon Resonance Physics

    CERN Document Server

    Burkert, Volker D

    2016-01-01

    Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the discovery of new excited nucleon and $\\Delta$ states using multi-channel partial wave analyses procedures. The internal structure of several prominent excited states has been revealed employing meson electroproduction processes. On the theoretical front, lattice QCD is now predicting the baryon spectrum with very similar characteristics as the constituent quark model, and continuum QCD, such as is represented in the Dyson-Schwinger Equations approach and in light front relativistic quark models, describes the non-perturbative behavior of resonance excitations at photon virtuality of $Q^2 > 1.5GeV^2$. In this talk I discuss the need to continue a vigorous program of nucleon spectroscopy and the study of the internal structure of excited states as a way to reveal the effective degre...

  16. Nucleon Resonance Physics

    Science.gov (United States)

    Burkert, Volker D.

    2016-10-01

    Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the discovery of new excited nucleon and Δ states using multi-channel partial wave analyses procedures. The internal structure of several prominent excited states has been revealed employing meson electroproduction processes. On the theoretical front, lattice QCD is now predicting the baryon spectrum with very similar characteristics as the constituent quark model, and continuum QCD, such as is represented in the Dyson-Schwinger equations approach and in light front relativistic quark models, describes the non-perturbative behavior of resonance excitations at photon virtuality of Q^2 > 1.5 GeV^2. In this talk I discuss the need to continue a vigorous program of nucleon spectroscopy and the study of the internal structure of excited states as a way to reveal the effective degrees of freedom underlying the excited states and their dependence on the distance scale probed.

  17. Tunable Micro- and Nanomechanical Resonators

    Science.gov (United States)

    Zhang, Wen-Ming; Hu, Kai-Ming; Peng, Zhi-Ke; Meng, Guang

    2015-01-01

    Advances in micro- and nanofabrication technologies have enabled the development of novel micro- and nanomechanical resonators which have attracted significant attention due to their fascinating physical properties and growing potential applications. In this review, we have presented a brief overview of the resonance behavior and frequency tuning principles by varying either the mass or the stiffness of resonators. The progress in micro- and nanomechanical resonators using the tuning electrode, tuning fork, and suspended channel structures and made of graphene have been reviewed. We have also highlighted some major influencing factors such as large-amplitude effect, surface effect and fluid effect on the performances of resonators. More specifically, we have addressed the effects of axial stress/strain, residual surface stress and adsorption-induced surface stress on the sensing and detection applications and discussed the current challenges. We have significantly focused on the active and passive frequency tuning methods and techniques for micro- and nanomechanical resonator applications. On one hand, we have comprehensively evaluated the advantages and disadvantages of each strategy, including active methods such as electrothermal, electrostatic, piezoelectrical, dielectric, magnetomotive, photothermal, mode-coupling as well as tension-based tuning mechanisms, and passive techniques such as post-fabrication and post-packaging tuning processes. On the other hand, the tuning capability and challenges to integrate reliable and customizable frequency tuning methods have been addressed. We have additionally concluded with a discussion of important future directions for further tunable micro- and nanomechanical resonators. PMID:26501294

  18. Tunable Micro- and Nanomechanical Resonators

    Directory of Open Access Journals (Sweden)

    Wen-Ming Zhang

    2015-10-01

    Full Text Available Advances in micro- and nanofabrication technologies have enabled the development of novel micro- and nanomechanical resonators which have attracted significant attention due to their fascinating physical properties and growing potential applications. In this review, we have presented a brief overview of the resonance behavior and frequency tuning principles by varying either the mass or the stiffness of resonators. The progress in micro- and nanomechanical resonators using the tuning electrode, tuning fork, and suspended channel structures and made of graphene have been reviewed. We have also highlighted some major influencing factors such as large-amplitude effect, surface effect and fluid effect on the performances of resonators. More specifically, we have addressed the effects of axial stress/strain, residual surface stress and adsorption-induced surface stress on the sensing and detection applications and discussed the current challenges. We have significantly focused on the active and passive frequency tuning methods and techniques for micro- and nanomechanical resonator applications. On one hand, we have comprehensively evaluated the advantages and disadvantages of each strategy, including active methods such as electrothermal, electrostatic, piezoelectrical, dielectric, magnetomotive, photothermal, mode-coupling as well as tension-based tuning mechanisms, and passive techniques such as post-fabrication and post-packaging tuning processes. On the other hand, the tuning capability and challenges to integrate reliable and customizable frequency tuning methods have been addressed. We have additionally concluded with a discussion of important future directions for further tunable micro- and nanomechanical resonators.

  19. Probabilistic interpretation of resonant states

    Indian Academy of Sciences (India)

    Naomichi Hatano; Tatsuro Kawamoto; Joshua Feinberg

    2009-09-01

    We provide probabilistic interpretation of resonant states. We do this by showing that the integral of the modulus square of resonance wave functions (i.e., the conventional norm) over a properly expanding spatial domain is independent of time, and therefore leads to probability conservation. This is in contrast with the conventional employment of a bi-orthogonal basis that precludes probabilistic interpretation, since wave functions of resonant states diverge exponentially in space. On the other hand, resonant states decay exponentially in time, because momentum leaks out of the central scattering area. This momentum leakage is also the reason for the spatial exponential divergence of resonant state. It is by combining the opposite temporal and spatial behaviours of resonant states that we arrive at our probabilistic interpretation of these states. The physical need to normalize resonant wave functions over an expanding spatial domain arises because particles leak out of the region which contains the potential range and escape to infinity, and one has to include them in the total count of particles.

  20. From Autonomous Coherence Resonance to Periodically Driven Stochastic Resonance

    Institute of Scientific and Technical Information of China (English)

    CAO Zhou-Jian; LI Peng-Fei; HU Gang

    2007-01-01

    In periodically driven nonlinear stochastic systems,noise may play a role of enhancing the output periodic signal (termed as stochastic resonance or SR).While in autonomous excitable systems,noise may play a role of increasing coherent motion(termed as coherence resonance or CR).So far the topics of SR and CR have been investigated separately as two major fields of studying the active roles of noise in nonlinear systems.We find that these two topics are closely related to each other.Specifically,SR occurs in such periodically driven systems that the corresponding autonomous systems show CR.The SR with sensitive frequency dependence can be observed when the corresponding autonomous system shows CR with finite characteristic frequency.Moreover,'resonant noise' and 'resonant frequency' of SR coincide with those of CR.

  1. Advances in magnetic resonance 5

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 5 deals with the interpretation of ESR spectra and provides descriptions of experimental apparatus. This book discusses the halogen hyperfine interactions; organic radicals in single crystals; pulsed-Fourier-transform nuclear magnetic resonance spectrometer; and inhomogenizer and decoupler. The spectrometers for multiple-pulse NMR; weak collision theory of relaxation in the rotating frame; and spin Hamiltonian for the electron spin resonance of irradiated organic single crystals are also deliberated. This text likewise covers the NMR in helium three and m

  2. Nonlinear behavior of Helmholtz resonators

    Science.gov (United States)

    Hersh, A. S.

    1990-10-01

    A semi-empirical fluid mechanical model has been derived to predict the nonlinear acoustic behavior of thin-walled, single-orifice Helmholtz resonators. The model assumed that the sound particle velocity field approaches the resonator in a spherically symmetric manner. The incident and cavity sound pressure fields are connected in terms of an orifice discharge coefficient and an end correction parameter whose values are determined empirically. The accuracy of the model was verified by comparing predicted with measured impedance over a wide range of sound amplitudes and frequencies for two different resonator geometries and with measurements conducted by Ingard and Ising.

  3. Advances in magnetic resonance 1

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 1, discusses developments in various areas of magnetic resonance. The subject matter ranges from original theoretical contributions through syntheses of points of view toward series of phenomena to critical and painstaking tabulations of experimental data. The book contains six chapters and begins with a discussion of the theory of relaxation processes. This is followed by separate chapters on the development of magnetic resonance techniques for studying rate processes in chemistry and the application of these techniques to various problems; the geometri

  4. Nanoscale nonlinear PANDA ring resonator

    CERN Document Server

    Yupapin, Preecha

    2012-01-01

    Microring/nanoring resonator is an interesting device that has been widely studied and investigated by researchers from a variety of specializations. This book begins with the basic background of linear and nonlinear ring resonators. A novel design of nano device known as a PANDA ring resonator is proposed. The use of the device in the form of a PANDA in applications such as nanoelectronics, measurement, communication, sensors, optical and quantum computing, drug delivery, hybrid transistor and a new concept of electron-hole pair is discussed in detail.

  5. Electromagnetic Excitation of Nucleon Resonances

    CERN Document Server

    Tiator, L; Kamalov, S S; Vanderhaeghen, M

    2011-01-01

    Recent progress on the extraction of electromagnetic properties of nucleon resonance excitation through pion photo- and electroproduction is reviewed. Cross section data measured at MAMI, ELSA, and CEBAF are analyzed and compared to the analysis of other groups. On this basis, we derive longitudinal and transverse transition form factors for most of the four-star nucleon resonances. Furthermore, we discuss how the transition form factors can be used to obtain empirical transverse charge densities. Contour plots of the thus derived densities are shown for the Delta, Roper, S11, and D13 nucleon resonances.

  6. Sound-resonance hydrogen sensor

    OpenAIRE

    Dong, Shuxiang; Bai, Feiming; Li, Jiefang; Viehland, Dwight D.

    2003-01-01

    A hydrogen sensor is reported in which a small piezoelectric-sound-resonance-cavity (PSRC) is used as the sensing element. Detection utilizes sound resonance and acoustic property differences between H-2 and air as a sensing mechanism. Changes in H-2 concentration result in a shift of the sound-resonance state of the PSRC. Preliminary experiments have demonstrated a sensitivity limit of 8 ppm, a fast response time similar to1.5 second, and detection capabilities over a broad concentration ran...

  7. Advances in magnetic resonance 9

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 9 describes the magnetic resonance in split constants and dipolar relaxation. This book discusses the temperature-dependent splitting constants in the ESR spectra of organic free radicals; temperature-dependent splittings in ion pairs; and magnetic resonance induced by electrons. The electron impact excitation of atoms and molecules; intramolecular dipolar relaxation in multi-spin systems; and dipolar cross-correlation problem are also elaborated. This text likewise covers the NMR studies of molecules oriented in thermotropic liquid crystals and diffusion

  8. Single-resonator double-negative metamaterial

    Science.gov (United States)

    Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Johnson, William A.; Ihlefeld, Jon; Ginn, III, James C.; Clem, Paul G.; Sinclair, Michael B.

    2016-06-21

    Resonances can be tuned in dielectric resonators in order to construct single-resonator, negative-index metamaterials. For example, high-contrast inclusions in the form of metallic dipoles can be used to shift the first electric resonance down (in frequency) to the first magnetic resonance, or alternatively, air splits can be used to shift the first magnetic resonance up (in frequency) near the first electric resonance. Degenerate dielectric designs become especially useful in infrared- or visible-frequency applications where the resonator sizes associated with the lack of high-permittivity materials can become of sufficient size to enable propagation of higher-order lattice modes in the resulting medium.

  9. Intraoperative magnetic resonance imaging.

    Science.gov (United States)

    Hall, Walter A; Truwit, Charles L

    2011-01-01

    Neurosurgeons have become reliant on image-guidance to perform safe and successful surgery both time-efficiently and cost-effectively. Neuronavigation typically involves either rigid (frame-based) or skull-mounted (frameless) stereotactic guidance derived from computed tomography (CT) or magnetic resonance imaging (MRI) that is obtained days or immediately before the planned surgical procedure. These systems do not accommodate for brain shift that is unavoidable once the cranium is opened and cerebrospinal fluid is lost. Intraoperative MRI (ioMRI) systems ranging in strength from 0.12 to 3 Tesla (T) have been developed in part because they afford neurosurgeons the opportunity to accommodate for brain shift during surgery. Other distinct advantages of ioMRI include the excellent soft tissue discrimination, the ability to view the surgical site in three dimensions, and the ability to "see" tumor beyond the surface visualization of the surgeon's eye, either with or without a surgical microscope. The enhanced ability to view the tumor being biopsied or resected allows the surgeon to choose a safe surgical corridor that avoids critical structures, maximizes the extent of the tumor resection, and confirms that an intraoperative hemorrhage has not resulted from surgery. Although all ioMRI systems allow for basic T1- and T2-weighted imaging, only high-field (>1.5 T) MRI systems are capable of MR spectroscopy (MRS), MR angiography (MRA), MR venography (MRV), diffusion-weighted imaging (DWI), and brain activation studies. By identifying vascular structures with MRA and MRV, it may be possible to prevent their inadvertent injury during surgery. Biopsying those areas of elevated phosphocholine on MRS may improve the diagnostic yield for brain biopsy. Mapping out eloquent brain function may influence the surgical path to a tumor being resected or biopsied. The optimal field strength for an ioMRI-guided surgical system and the best configuration for that system are as yet

  10. Cardiovascular Magnetic Resonance Imaging

    Science.gov (United States)

    Pelc, Norbert

    2000-03-01

    Cardiovascular diseases are a major source of morbidity and mortality in the United States. Early detection of disease can often be used to improved outcomes, either through direct interventions (e.g. surgical corrections) or by causing the patient to modify his or her behavior (e.g. smoking cessation or dietary changes). Ideally, the detection process should be noninvasive (i.e. it should not be associated with significant risk). Magnetic Resonance Imaging (MRI) refers to the formation of images by localizing NMR signals, typically from protons in the body. As in other applications of NMR, a homogeneous static magnetic field ( ~0.5 to 4 T) is used to create ``longitudinal" magnetization. A magnetic field rotating at the Larmor frequency (proportional to the static field) excites spins, converting longitudinal magnetization to ``transverse" magnetization and generating a signal. Localization is performed using pulsed gradients in the static field. MRI can produce images of 2-D slices, 3-D volumes, time-resolved images of pseudo-periodic phenomena such as heart function, and even real-time imaging. It is also possible to acquire spatially localized NMR spectra. MRI has a number of advantages, but perhaps the most fundamental is the richness of the contrast mechanisms. Tissues can be differentiated by differences in proton density, NMR properties, and even flow or motion. We also have the ability to introduce substances that alter NMR signals. These contrast agents can be used to enhance vascular structures and measure perfusion. Cardiovascular MRI allows the reliable diagnosis of important conditions. It is possible to image the blood vessel tree, quantitate flow and perfusion, and image cardiac contraction. Fundamentally, the power of MRI as a diagnostic tool stems from the richness of the contrast mechanisms and the flexibility in control of imaging parameters.

  11. Maturation of limbic regions in Asperger syndrome: a preliminary study using proton magnetic resonance spectroscopy and structural magnetic resonance imaging.

    Science.gov (United States)

    O'Brien, Finian M; Page, Lisa; O'Gorman, Ruth L; Bolton, Patrick; Sharma, Ajay; Baird, Gillian; Daly, Eileen; Hallahan, Brian; Conroy, Ronán M; Foy, Catherine; Curran, Sarah; Robertson, Dene; Murphy, Kieran C; Murphy, Declan G M

    2010-11-30

    People with autistic spectrum disorders (ASD, including Asperger syndrome) may have developmental abnormalities in the amygdala-hippocampal complex (AHC). However, in vivo, age-related comparisons of both volume and neuronal integrity of the AHC have not yet been carried out in people with Asperger syndrome (AS) versus controls. We compared structure and metabolic activity of the right AHC of 22 individuals with AS and 22 healthy controls aged 10-50 years and examined the effects of age between groups. We used structural magnetic resonance imaging (sMRI) to measure the volume of the AHC, and magnetic resonance spectroscopy ((1)H-MRS) to measure concentrations of N-acetyl aspartate (NAA), creatine+phosphocreatine (Cr+PCr), myo-inositol (mI) and choline (Cho). The bulk volume of the amygdala and the hippocampus did not differ significantly between groups, but there was a significant difference in the effect of age on the hippocampus in controls. Compared with controls, young (but not older) people with AS had a significantly higher AHC concentration of NAA and a significantly higher NAA/Cr ratio. People with AS, but not controls, had a significant age-related reduction in NAA and the NAA/Cr ratio. Also, in people with AS, but not controls, there was a significant relationship between concentrations of choline and age so that choline concentrations reduced with age. We therefore suggest that people with AS have significant differences in neuronal and lipid membrane integrity and maturation of the AHC.

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to ...

  13. Controlling Metamaterial Resonances with Light

    CERN Document Server

    Chakrabarti, Sangeeta; Wanare, Harshawardhan

    2010-01-01

    We investigate the use of coherent optical fields as a means of dynamically controlling the resonant behaviour of a variety of composite metamaterials, wherein the metamaterial structures are embedded in a dispersive dielectric medium. Control and switching is implemented by coherently driving the resonant permittivity of the embedding medium by applied optical radiation. The effect of embedding Split ring resonators (SRR) in a frequency- dispersive medium with Lorentz-like dispersion or with dispersion engineered by electromagnetic induced transparency (EIT), is manifested in the splitting of the negative permeability band, the modified (frequency-dependent) filling fractions and dissipation factors. The modified material parameters are strongly linked to the resonant frequencies of the medium, while for an embedding medium exhibiting EIT, also to the strength and detuning of the control field. The robustness of control against the deleterious influence of dissipation associated with the metallic structures ...

  14. Magnetic resonance imaging the basics

    CERN Document Server

    Constantinides, Christakis

    2014-01-01

    Magnetic resonance imaging (MRI) is a rapidly developing field in basic applied science and clinical practice. Research efforts in this area have already been recognized with five Nobel prizes awarded to seven Nobel laureates in the past 70 years. Based on courses taught at The Johns Hopkins University, Magnetic Resonance Imaging: The Basics provides a solid introduction to this powerful technology. The book begins with a general description of the phenomenon of magnetic resonance and a brief summary of Fourier transformations in two dimensions. It examines the fundamental principles of physics for nuclear magnetic resonance (NMR) signal formation and image construction and provides a detailed explanation of the mathematical formulation of MRI. Numerous image quantitative indices are discussed, including (among others) signal, noise, signal-to-noise, contrast, and resolution. The second part of the book examines the hardware and electronics of an MRI scanner and the typical measurements and simulations of m...

  15. Nested trampoline resonators for optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, M. J., E-mail: mweaver@physics.ucsb.edu; Pepper, B.; Luna, F.; Perock, B. [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Buters, F. M.; Eerkens, H. J.; Welker, G.; Heeck, K.; Man, S. de [Huygens-Kamerlingh Onnes Laboratorium, Universiteit Leiden, 2333 CA Leiden (Netherlands); Bouwmeester, D. [Department of Physics, University of California, Santa Barbara, California 93106 (United States); Huygens-Kamerlingh Onnes Laboratorium, Universiteit Leiden, 2333 CA Leiden (Netherlands)

    2016-01-18

    Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating trampoline resonators made from low pressure chemical vapor deposition Si{sub 3}N{sub 4} with a distributed Bragg reflector mirror. We design a nested double resonator structure with 80 dB of mechanical isolation from the mounting surface at the inner resonator frequency, and we demonstrate up to 45 dB of isolation at lower frequencies in agreement with the design. We reliably fabricate devices with mechanical quality factors of around 400 000 at room temperature. In addition, these devices were used to form optical cavities with finesse up to 181 000 ± 1000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

  16. Calligraphic Poling for WGM Resonators

    Science.gov (United States)

    Mohageg, Makan; Strekalov, Dmitry; Savchenkov, Anatoliy; Matsko, Andrey; Ilchenko, Vladimir; Maleki, Lute

    2007-01-01

    By engineering the geometry of a nonlinear optical crystal, the effective efficiency of all nonlinear optical oscillations can be increased dramatically. Specifically, sphere and disk shaped crystal resonators have been used to demonstrate nonlinear optical oscillations at sub-milliwatt input power when cs light propagates in a Whispering Gallery Mode (WGM) of such a resonant cavity. in terms of both device production and experimentation in quantum optics, some nonlinear optical effects with naturally high efficiency can occult the desired nonlinear scattering process. the structure to the crystal resonator. In this paper, I will discuss a new method for generating poling structures in ferroelectric crystal resonators called calligraphic poling. The details of the poling apparatus, experimental results and speculation on future applications will be discussed.

  17. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed pictures ... medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed ...

  18. Superhumps, resonances and accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Whitehurst, R.; King, A. (Leicester Univ. (UK). Dept. of Astronomy)

    1991-03-01

    The structure of accretion discs within binary systems is shown to be influenced by the excitation of resonances within the disc. Of particular importance is that near the 3:1 commensurability with the stars' orbit. This can be used to explain the superhump phenomenon of SU Ursae Majoris dwarf novae in superoutburst. This resonance can only appear for mass ratios which satisfy M{sub 2}/M{sub 1} < {approx equal} 0.25-0.33: for larger mass ratios the available resonances are weaker and of the wrong form to produce the superhump phenomenon. The mass-transfer stream is shown to be an important contributor to the growth rate of the resonance. (author).

  19. Nested Trampoline Resonators for Optomechanics

    CERN Document Server

    Weaver, Matthew J; Luna, Fernando; Buters, Frank M; Eerkens, Hedwig J; Welker, Gesa; Perock, Blaise; Heeck, Kier; de Man, Sven; Bouwmeester, Dirk

    2015-01-01

    Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating novel trampoline resonators made from low pressure chemical vapor deposition (LPCVD) Si$_3$N$_4$ with a distributed bragg reflector (DBR) mirror. We construct a nested double resonator structure that generates approximately 80 dB of mechanical isolation from the mounting surface, eliminating the strong mounting dependence of the quality factor observed with single resonators. With the consistency provided by this isolation scheme we reliably fabricate devices with mechanical quality factors of around 400,000 at room temperature. In addition these devices were used to form optical cavities with finesse up to 181,000 $\\pm$ 1,000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the head is performed ...

  1. Ion Cyclotron Resonance Facility (ICR)

    Data.gov (United States)

    Federal Laboratory Consortium — his facility is charged with developing and exploiting the unique capabilities of Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry, and leads the...

  2. Magnetic Resonance Imaging (MRI) -- Head

    Science.gov (United States)

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  4. Nucleon Resonances in Kaon Photoproduction

    CERN Document Server

    Bennhold, C; Waluyo, A; Haberzettl, H; Penner, G; Feuster, T; Mosel, U

    1999-01-01

    Nucleon resonances are investigated through the electromagnetic production of K-mesons. We study the kaon photoproduction process at tree-level and compare to a recently developed unitary K-matrix approach. Employing hadronic form factors along with the proper gauge prescription yields suppression of the Born terms and leads a resonance dominated process for both K-Lambda and K-Sigma photoproduction. Using new SAPHIR data we find the K+-Lambda photoproduction to be dominated by the S11(1650) at threshold, with additional contributions from the P11(1710) and P13(1720) states. The K-Sigma channel couples to a cluster of Delta resonances around W = 1900 MeV. We briefly discuss some tantalizing evidence for a missing D13 resonance around 1900 MeV with a strong branching ratio into KLambda channel.

  5. Nanocatalytic resonance scattering spectral analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The resonance scattering spectral technique has been established using the synchronous scanning technique on spectrofluorometry.Because of its advantages of simplicity,rapidity and sensitivity,it has been widely applied to analyses of proteins,nucleic acids and inorganic ions.This paper summarizes the application of immunonanogold and aptamer modified nanogold(AptAu) catalytic resonance scattering spectral technique in combination with the work of our group,citing 53 references.

  6. Advances in magnetic resonance 4

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 4 deals with the relaxation, irradiation, and other dynamical effects that is specific to systems having resolved structure in their magnetic resonance spectra. This book discusses the anisotropic rotation of molecules in liquids by NMR quadrupolar relaxation; rotational diffusion constants; alternating linewidth effect; and theoretical formulations of the problem. The line shapes in high-resolution NMR; matrix representations of the equations of motion; matrix representations of the equations of motion; and intramolecular hydrogen bonds are also delibera

  7. Electromagnetic properties of baryon resonances

    CERN Document Server

    Tiator, Lothar

    2012-01-01

    Longitudinal and transverse transition form factors for most of the four-star nucleon resonances have been obtained from high-quality cross section data and polarization observables measured at MAMI, ELSA, BATES, GRAAL and CEBAF. As an application, we further show how the transition form factors can be used to obtain empirical transverse charge densities. Contour plots of the thus derived densities are shown and compared for the Roper and S11 nucleon resonances.

  8. de Sitter as a Resonance

    CERN Document Server

    Maltz, Jonathan

    2016-01-01

    A quantum mechanical formulation of de Sitter cosmological spacetimes still eludes string theory. In this paper we conjecture a potentially rigorous framework in which the status of de Sitter space is the same as that of a resonance in a scattering process. We conjecture that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant poles characteristic meta-stable intermediate states. A calculation employing constrained instantons illustrates this idea.

  9. Advances in magnetic resonance 2

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 2, features a mixture of experimental and theoretical contributions. The book contains four chapters and begins with an ambitious and general treatment of the problem of signal-to-noise ratio in magnetic resonance. This is followed by separate chapters on the interpretation of nuclear relaxation in fluids, with special reference to hydrogen; and various aspects of molecular theory of importance in NMR.

  10. Micro-machined resonator oscillator

    Science.gov (United States)

    Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

    1994-01-01

    A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

  11. Universal formalism of Fano resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Liang [School of Physical Science and Technology and Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, Gansu 730000 (China); Lai, Ying-Cheng [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Institute for Complex Systems and Mathematical Biology, King’s College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Luo, Hong-Gang [School of Physical Science and Technology and Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, Gansu 730000 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Grebogi, Celso [Institute for Complex Systems and Mathematical Biology, King’s College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom)

    2015-01-15

    The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset). The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.

  12. Universal formalism of Fano resonance

    Directory of Open Access Journals (Sweden)

    Liang Huang

    2015-01-01

    Full Text Available The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset. The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.

  13. Mass detection using capacitive resonant silicon resonator employing LC resonant circuit technique.

    Science.gov (United States)

    Kim, Sang-Jin; Ono, Takahito; Esashi, Masayoshi

    2007-08-01

    Capacitive resonant mass sensing using a single-crystalline silicon resonator with an electrical LC oscillator was demonstrated in ambient atmosphere. Using capacitive detection method, the detectable minimum mass of 1 x 10(-14) g was obtained in the self-oscillation of cantilever with a thickness of 250 nm. The noise amplitude of the sensor output corresponds to a vibration amplitude of 0.05 nm(Hz)(0.5) in the frequency domain compared with the actuation signal, which is equivalent to the detectable minimum capacitance variation of 2.4 x 10(-21) F. Using the capacitive detection method, mass/stress induced resonance frequency shift due to the adsorption of ethanol and moist vapor in a pure N(2) gas as a carrier is successfully demonstrated. These results show the high potential of capacitive silicon resonator for high mass/stress-sensitive sensor.

  14. Study on resonance frequency of thermoacoustic resonance pipes

    Institute of Scientific and Technical Information of China (English)

    FAN Li; WANG Benren; JIN Tao; ZHANG Shuyi

    2005-01-01

    For calculating the resonance frequency of practical resonance pipes more precisely, two methods are presented, which are the method of acoustic pressure simulation and the method of minimum point of standing wave. Both methods are based on the theoretical simulation of the acoustic pressure distribution in the pipe and the relation between the minimum point position of the standing wave and the acoustic impedances of the pipe terminations.It is demonstrated that both methods can calculate the resonance frequency of a pipe more precisely by considering the effect of the acoustic resistances of both terminations of the pipe.Therefore both methods presented are more useful in acoustic research fields in which the resonance frequency of a pipe must be controlled strictly. In addition, both methods can get the same calculation results despite of their different ways. The method of the minimum point of standing wave is more convenient, nevertheless the method of acoustic pressure simulation can derive the resonance frequency and the distribution of the acoustic pressure in the pipe simultaneously.

  15. Resonance capture cross section of 207Pb

    CERN Document Server

    Domingo-Pardo, C; Aerts, G; Alvarez-Pol, H; Alvarez-Velarde, F; Andrzejewski, J; Andriamonje, Samuel A; Assimakopoulos, P A; Audouin, L; Badurek, G; Baumann, P; Becvar, F; Berthoumieux, E; Bisterzo, S; Calviño, F; Cano-Ott, D; Capote, R; Carrapico, C; Chepel, V; Cennini, P; Chiaveri, Enrico; Colonna, N; Cortés, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillman, I; Dolfini, R; Dridi, W; Durán, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Kölbl, H; Fujii, K; Furman, W; Gallino, R; Gonçalves, I; González-Romero, E M; Goverdovski, A; Gramegna, F; Griesmayer, E; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Igashira, M; Isaev, S; Jericha, E; Kadi, Y; Käppeler, F K; Karamanis, D; Karadimos, D; Kerveno, M; Ketlerov, V; Köhler, P; Konovalov, V; Kossionides, E; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, Heinz; Oshima, M; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Plag, R; Plompen, A; Plukis, A; Poch, A; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Sarchiapone, L; Savvidis, I; Stéphan, C; Tagliente, G; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente6, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2006-01-01

    The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.

  16. Transmission Line Resonator Segmented with Series Capacitors

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Boer, Vincent; Petersen, Esben Thade

    2016-01-01

    Transmission line resonators are often used as coils in high field MRI. Due to distributed nature of such resonators, coils based on them produce inhomogeneous field. This work investigates application of series capacitors to improve field homogeneity along the resonator. The equations for optimal...... values of evenly distributed capacitors are presented. The performances of the segmented resonator and a regular transmission line resonator are compared....

  17. Aging and Aged in Organized Crime.

    Science.gov (United States)

    Amir, Menachem

    1989-01-01

    Examines problems of the aged in organized crime, basing discussion on organized crime bosses over age 60 operating in Italy, the United States, and Israel. Looks at problems stemming from normative system in organized crime, role of the aged, intergenerational problems, fears of the aged, excuses and justifications, standards of life, and…

  18. Structural Colors from Fano Resonances

    CERN Document Server

    Shen, Yichen; Wang, Imbert; Stelmakh, Veronika; Joannopoulos, John D; Soljacic, Marin

    2014-01-01

    Structural coloration is an interference phenomenon where colors emerge when visible light interacts with nanoscopically structured material, and has recently become a most interesting scientific and engineering topic. However, current structural color generation mechanisms either require thick (compared to the wavelength) structures or lack dynamic tunability. This report proposes a new structural color generation mechanism, that produces colors by the Fano resonance effect on thin photonic crystal slab. We experimentally realize the proposed idea by fabricating the samples that show resonance-induced colors with weak dependence on the viewing angle. Finally, we show that the resonance-induced colors can be dynamically tuned by stretching the photonic crystal slab fabricated on an elastic substrate.

  19. Holographic Kondo and Fano Resonances

    CERN Document Server

    Erdmenger, Johanna; O'Bannon, Andy; Papadimitriou, Ioannis; Probst, Jonas; Wu, Jackson M S

    2016-01-01

    We use holography to study a $(1+1)$-dimensional Conformal Field Theory (CFT) coupled to an impurity. The CFT is an $SU(N)$ gauge theory at large $N$, with strong gauge interactions. The impurity is an $SU(N)$ spin. We trigger an impurity Renormalization Group (RG) flow via a Kondo coupling. The Kondo effect occurs only below the critical temperature of a large-$N$ mean-field transition. We show that at all temperatures $T$, spectral functions of certain bosonic operators exhibit a Fano resonance, which in the low-$T$ phase is a large-$N$ manifestation of the Kondo resonance. Such Fano resonances are characteristic features of RG flows between $(0+1)$-dimensional fixed points, and are thus distinct from those observed for example in quantum dots.

  20. Viscoelastic coupling of nanoelectromechanical resonators.

    Energy Technology Data Exchange (ETDEWEB)

    Simonson, Robert Joseph; Staton, Alan W.

    2009-09-01

    This report summarizes work to date on a new collaboration between Sandia National Laboratories and the California Institute of Technology (Caltech) to utilize nanoelectromechanical resonators designed at Caltech as platforms to measure the mechanical properties of polymeric materials at length scales on the order of 10-50 nm. Caltech has succeeded in reproducibly building cantilever resonators having major dimensions on the order of 2-5 microns. These devices are fabricated in pairs, with free ends separated by reproducible gaps having dimensions on the order of 10-50 nm. By controlled placement of materials that bridge the very small gap between resonators, the mechanical devices become coupled through the test material, and the transmission of energy between the devices can be monitored. This should allow for measurements of viscoelastic properties of polymeric materials at high frequency over short distances. Our work to date has been directed toward establishing this measurement capability at Sandia.

  1. Resonance Ionization Laser Ion Sources

    CERN Document Server

    Marsh, B

    2013-01-01

    The application of the technique of laser resonance ionization to the production of singly charged ions at radioactive ion beam facilities is discussed. The ability to combine high efficiency and element selectivity makes a resonance ionization laser ion source (RILIS) an important component of many radioactive ion beam facilities. At CERN, for example, the RILIS is the most commonly used ion source of the ISOLDE facility, with a yearly operating time of up to 3000 hours. For some isotopes the RILIS can also be used as a fast and sensitive laser spectroscopy tool, provided that the spectral resolution is sufficiently high to reveal the influence of nuclear structure on the atomic spectra. This enables the study of nuclear properties of isotopes with production rates even lower than one ion per second and, in some cases, enables isomer selective ionization. The solutions available for the implementation of resonance laser ionization at radioactive ion beam facilities are summarized. Aspects such as the laser r...

  2. A MEMS diamond hemispherical resonator

    Science.gov (United States)

    Bernstein, J. J.; Bancu, M. G.; Cook, E. H.; Chaparala, M. V.; Teynor, W. A.; Weinberg, M. S.

    2013-12-01

    In this paper we report the fabrication of hemispherical polycrystalline diamond resonators fabricated on a novel high-temperature glass substrate. The hemispherical resonator gyroscope is one of the most accurate and rugged of the mechanical gyroscopes, and can be operated in either rate or whole-angle mode due to its high degree of symmetry. A fabrication sequence for creating extremely symmetric 3D MEMS hemispheres is presented. Mode shapes and frequencies obtained with a laser vibrometer are shown, as well as curves of Q versus pressure, and the dependence of frequency on anchor size. Fundamental mode frequency matching to gyroscope operation in whole-angle mode.

  3. Resonant Bloch-wave beatings.

    Science.gov (United States)

    Kartashov, Yaroslav V; Vysloukh, Victor A; Torner, Lluis

    2014-07-01

    We introduce Bloch-wave beatings in arrays of multimode periodically bent waveguides with a transverse refractive index gradient. The new phenomenon manifests itself in the periodic drastic increase of the amplitude of the Bloch oscillations that accompanies resonant conversion of modes guided by the individual waveguides. The Bloch-wave beatings are found to be most pronounced when the length of the resonant mode conversion substantially exceeds the longitudinal period of the Bloch oscillations. The beating frequency decreases when the amplitude of waveguide bending decreases, while the beating amplitude is restricted by the amplitude of the Bloch oscillations that emerge from the second allowed band of the Floquet-Bloch lattice spectrum.

  4. Resonant Bloch-wave beatings

    CERN Document Server

    Kartashov, Yaroslav V; Torner, Lluis

    2014-01-01

    We introduce Bloch-wave beatings in arrays of multimode periodically bent waveguides with a transverse refractive index gradient. The new phenomenon manifests itself in the periodic drastic increase of the amplitude of the Bloch oscillations that accompanies resonant conversion of modes guided by the individual waveguides. The Bloch-wave beatings are found to be most pronounced when the length of the resonant mode conversion substantially exceeds the longitudinal period of the Bloch oscillations. The beating frequency decreases when the amplitude of waveguide bending decreases, while the beating amplitude is restricted by the amplitude of the Bloch oscillations that emerge from the second allowed band of the Floquet-Bloch lattice spectrum.

  5. Coupled-resonator optical waveguides

    DEFF Research Database (Denmark)

    Raza, Søren; Grgic, Jure; Pedersen, Jesper Goor;

    2010-01-01

    Coupled-resonator optical waveguides hold potential for slow-light propagation of optical pulses. The dispersion properties may adequately be analyzed within the framework of coupled-mode theory. We extend the standard coupled-mode theory for such structures to also include complex......-valued parameters which allows us to analyze the dispersion properties also in presence of finite Q factors for the coupled resonator states. Near the band-edge the group velocity saturates at a finite value vg/c µ p1/Q while in the band center, the group velocity is unaffected by a finite Q factor as compared...

  6. Parametric resonance in ideal magnetohydrodynamics

    Science.gov (United States)

    Zaqarashvili

    2000-08-01

    We show that an external nonelectromagnetic periodic inhomogeneous force sets up a parametric resonance in an ideal magnetohydrodynamics. Alfven waves with certain wavelengths grow exponentially in amplitude. Nonlinear interaction between the resonant harmonics produces the long-term modulation of amplitudes. The mechanism of the energy transformation from an external nonelectromagnetic force to magnetic oscillations of the system presented here can be used in understanding the physical background of the gravitational action on the magnetized medium. Future application of this theory to several astrophysical problems is briefly discussed.

  7. magnetic resonance imaging,etc.

    Institute of Scientific and Technical Information of China (English)

    张福基

    1998-01-01

    magnetic resonance imaging n.[1984] a noninvasive diagnostic technique that produces computerized images of internal body tissues and is based on nuclear magnetic resonance of atoms within he body induced by the application of radio waves磁共振成像(指一种非侵害 性诊断技术,能生成内部身体组织的计算机化影像,其依据是应用无线电波 感生体内原子并使之产磁共振)

  8. Resonance modes in optical fibres

    Institute of Scientific and Technical Information of China (English)

    余寿绵; 余恬

    2002-01-01

    The weakly nonlinear boundary value problem of wave propagation in an optical fibre (for the transverse electric mode, for example) is formulated and a modified linear solution is obtained. It is shown that a self-consistent theory of fibre optics should be weakly nonlinear. The mode of critical refraction that does not exist in the linear theory is obtained, showing that it is a mode consisting of resonance modes. It is shown that the signal carriers in a long fibre are of resonance modes, not normal modes. Some experimental data are given for comparison with the theoretical predictions, and the agreement seems satisfactory.

  9. Resonances in -light nucleus systems

    Indian Academy of Sciences (India)

    K P Khemchandani; N G Kelkar; M Nowakowski; B K Jain

    2006-04-01

    We locate resonances in -light nucleus elastic scattering using the time delay method. We solve few-body equations within the finite rank approximation in order to calculate the -matrices and hence the time delay for the - 3He and - 4He systems. We find a resonance very close to the threshold in - 3 He elastic scattering, at about 0.5 MeV above threshold with a width of ∼ 2 MeV. The calculations also hint at the presence of sub-threshold states in both the cases.

  10. Advances in magnetic resonance 8

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 8 describes the magnetic resonance in spin polarization and saturation transfer. This book discusses the theory of chemically induced dynamic spin polarization; basic results for the radical-pair mechanism; and optical spin polarization in molecular crystals. The theory of optical electronic polarization (OEP); NMR in flowing systems; and applications of NMR in a flowing liquid are also elaborated. This text likewise covers the saturation transfer spectroscopy; studies of spin labels in the intermediate and fast motion regions; and spin-density matrix and

  11. Controlling a diatomic shape resonance with non-resonant light

    CERN Document Server

    Aganoglu, Ruzin; Friedrich, Bretislav; González-Férez, Rosario; Koch, Christiane P

    2011-01-01

    A (diatomic) shape resonance is a metastable state of a pair of colliding atoms quasi-bound by the centrifugal barrier imposed by the angular momentum involved in the collision. The temporary trapping of the atoms' scattering wavefunction corresponds to an enhanced atom pair density at low interatomic separations. This leads to larger overlap of the wavefunctions involved in a molecule formation process such as photoassociation, rendering the process more efficient. However, for an ensemble of atoms, the atom pair density will only be enhanced if the energy of the resonance comes close to the temperature of the atomic ensemble. Herein we explore the possibility of controlling the energy of a shape resonance by shifting it toward the temperature of atoms confined in a trap. The shifts are imparted by the interaction of non-resonant light with the anisotropic polarizability of the atom pair, which affects both the centrifugal barrier and the pair's rotational and vibrational levels. We find that at laser intens...

  12. Quantifying resonant and near-resonant interactions in rotating turbulence

    CERN Document Server

    di Leoni, P Clark

    2016-01-01

    Nonlinear triadic interactions are at the heart of our understanding of turbulence. In flows where waves are present modes must not only be in a triad to interact, but their frequencies must also satisfy an extra condition: the interactions that dominate the energy transfer are expected to be resonant. We derive equations that allow direct measurement of the actual degree of resonance of each triad in a turbulent flow. We then apply the method to the case of rotating turbulence, where eddies coexist with inertial waves. We show that for a range of wave numbers, resonant and near-resonant triads are dominant, the latter allowing a transfer of net energy towards two-dimensional modes that would be inaccessible otherwise. The results are in good agreement with approximations often done in theories of rotating turbulence, and with the mechanism of parametric instability proposed to explain the development of anisotropy in such flows. We also observe that, at least for the moderate Rossby numbers studied here, mar...

  13. Resonant interaction modified by the atomic environment

    Energy Technology Data Exchange (ETDEWEB)

    Sainz, I; Klimov, A B; Chumakov, S M [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, 44410, Guadalajara, Jal. (Mexico)

    2003-04-01

    The dynamics of a resonant atom interacting with a quantum cavity field in the presence of many off-resonant atoms is studied. In the framework of the effective Hamiltonian approach we show that the results of elimination of non-resonant transitions are (a) a dynamical Stark shift of the field frequency, dependent on the populations of non-resonant atoms, (b) dependence of the coupling constant between the resonant atom and the field on the populations of non-resonant atoms, and (c) an effective dipole-dipole interaction between non-resonant atoms. Two effects (the coherent influence and dephasing) of the off-resonant environment on the dynamics of the resonant atom are discussed.

  14. Resonance, Multi-resonance, and Reverse-resonance Induced by Multiplicative Dichotomous Noise

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A constant-potential system driven by multiplicative dichotomous noise and subject to an input oscillatory signal is investigated. Two phenomena of stochastic resonance are observed. One is the response as a function of the noise's parameters; the other is that as a function of the input signal frequency. A phenomenon of multi-resonance (there are three or four peaks) is found for the response as a function of a parameter of the noise. A phenomenon of reverse-resonance is found, for which the response of the system to the signal can be weakened by the presence of the noise (there is an optimal minimum). These results help in studies of the systems with multiplicative dichotomous noise, such as the semiconductor, the proteins motor, the chemical reaction, and so on.

  15. Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization

    Institute of Scientific and Technical Information of China (English)

    Johnathan; C; Chung; Neel; K; Naik; Robert; J; Lewandowski; Mary; F; Mulcahy; Laura; M; Kulik; Kent; T; Sato; Robert; K; Ryu; Riad; Salem; Andrew; C; Larson; Reed; A; Omary

    2010-01-01

    AIM: To investigate whether intra-procedural diffusion- weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during trans- catheter arterial chemoembolization (TACE). METHODS: Sixteen patients (15 male), aged 59 ±11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Ana- tomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm2) were performed on a 1.5-T unit. ...

  16. Resonance in Bottles with Different Shapes

    Directory of Open Access Journals (Sweden)

    Amy Elliott

    2012-01-01

    Full Text Available The Helmholtz Resonance equation derived in the 1800’s describes the nature of resonance in narrow-necked vessels, known as Helmholtz Resonators. It is commonly accepted that when air is blown across the opening of a bottle, the resonance can be modeled by the Helmholtz equation. Resonance was studied in two differently shaped bottles as the volume of the air cavity was varied. It was found that resonance in one of the bottles was accurately modeled by the Helmholtz equation but not in the other.

  17. Helmholtz Resonance in a Water Bottle

    Directory of Open Access Journals (Sweden)

    Annirudh Balachandran

    2011-01-01

    Full Text Available The resonance that occurs when blowing across the top of a water bottle filled with different volumes of water was studied. It was shown that, contrary to popular belief, a water bottle is not an ideal Helmholtz resonator. Resonance in a water bottle with an extendable neck was then studied to determine how the length of the neck affects the resonance. The results showed that ideal Helmholtz resonance occurs when the neck length was in a middle range, while for no neck a standing wave resonance occurs. For a very long neck the results were inconclusive.

  18. Meson resonances on the lattice

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-06-01

    There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems

  19. Meson Resonances from Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-06-01

    There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems.

  20. Magnetic Resonance Image Wavelet Enhancer

    Science.gov (United States)

    2007-11-02

    1Departamento de Ingenieria Electrica, UAM Iztapalapa, Mexico−DF, 09340, Mexico email:arog@xanum.uam.mx. Magnetic Resonance Centre, School of Physics...Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Departamento de Ingenieria Electrica, UAM Iztapalapa, Mexico-DF

  1. Biosensing by WGM Microspherical Resonators

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2016-06-01

    Full Text Available Whispering gallery mode (WGM microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed.

  2. Interface losses in multimaterial resonators

    DEFF Research Database (Denmark)

    Villanueva, L.G.; Amato, B.; Larsen, Tom;

    2014-01-01

    We present an extensive study shedding light on the role of surface and bulk losses in micromechanical resonators. We fabricate thin silicon nitride membranes of different sizes and we coat them with different thicknesses of metal. We later characterize the 81 lowest out-of-plane flexural vibrati...

  3. Algebraic model of baryon resonances

    CERN Document Server

    Bijker, R

    1997-01-01

    We discuss recent calculations of electromagnetic form factors and strong decay widths of nucleon and delta resonances. The calculations are done in a collective constituent model of the nucleon, in which the baryons are interpreted as rotations and vibrations of an oblate top.

  4. Resonances in retrograde circumbinary discs

    CERN Document Server

    Nixon, Chris

    2015-01-01

    We analyse the interaction of an eccentric binary with a circular coplanar circumbinary disc that rotates in a retrograde sense with respect to the binary. In the circular binary case, no Lindblad resonances lie within the disc and no Lindblad resonant torques are produced, as was previously known. By analytic means, we show that when the binary orbit is eccentric, there exist components of the gravitational potential of the binary which rotate in a retrograde sense to the binary orbit and so rotate progradely with respect to this disc, allowing a resonant interaction to occur between the binary and the disc. The resulting resonant torques distinctly alter the disc response from the circular binary case. We describe results of three-dimensional hydrodynamic simulations to explore this effect and categorise the response of the disc in terms of modes whose strengths vary as a function of binary mass ratio and eccentricity. These mode strengths are weak compared to the largest mode strengths expected in the prog...

  5. Evanescent Waves Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order...

  6. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... E-mail: Area code: Phone no: Thank you! Images × Image Gallery Radiologist prepping patient for magnetic resonance imaging ( ... address): From (your name): Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... E-mail: Area code: Phone no: Thank you! Images × Image Gallery Magnetic Resonance Imaging (MRI) procedure View full ... address): From (your name): Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your ...

  8. Tuning Fano Resonances with Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Prokopeva, Ludmila

    2013-01-01

    We demonstrate strong electrical control of plasmonic Fano resonances in dolmen structures using tunable interband transitions in graphene. Such graphene-plasmonic hybrid devices can have applications in light modulation and sensing. OCIS codes: (250.5403) Plasmonics; (160.4670) Optical materials...

  9. Entropy production by resonance decays

    CERN Document Server

    Ochs, S; Ochs, Stefan; Heinz, Ulrich

    1996-01-01

    We investigate entropy production for an expanding system of particles and resonances with isospin symmetry -- in our case pions and \\rho mesons -- within the framework of relativistic kinetic theory. A cascade code to simulate the kinetic equations is developed and results for entropy production and particle spectra are presented.

  10. Biosensing by WGM Microspherical Resonators

    Science.gov (United States)

    Righini, Giancarlo C.; Soria, Silvia

    2016-01-01

    Whispering gallery mode (WGM) microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed. PMID:27322282

  11. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ...

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ...

  13. Inelastic scattering in resonant tunneling

    DEFF Research Database (Denmark)

    Wingreen, Ned S.; Jacobsen, Karsten Wedel; Wilkins, John W.

    1989-01-01

    The exact resonant-tunneling transmission probability for an electron interacting with phonons is presented in the limit that the elastic coupling to the leads is independent of energy. The phonons produce transmission sidebands but do not affect the integrated transmission probability or the esc...

  14. Composite Resonator Surface Emitting Lasers

    Energy Technology Data Exchange (ETDEWEB)

    FISCHER,ARTHUR J.; CHOQUETTE,KENT D.; CHOW,WENG W.; ALLERMAN,ANDREW A.; GEIB,KENT M.

    2000-05-01

    The authors have developed electrically-injected coupled-resonator vertical-cavity lasers and have studied their novel properties. These monolithically grown coupled-cavity structures have been fabricated with either one active and one passive cavity or with two active cavities. All devices use a selectively oxidized current aperture in the lower cavity, while a proton implant was used in the active-active structures to confine current in the top active cavity. They have demonstrated optical modulation from active-passive devices where the modulation arises from dynamic changes in the coupling between the active and passive cavities. The laser intensity can be modulated by either forward or reverse biasing the passive cavity. They have also observed Q-switched pulses from active-passive devices with pulses as short as 150 ps. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulseshape. They have designed and demonstrated the operation of active-active devices which la.se simultaneously at both longitudinal cavity resonances. Extremely large bistable regions have also been observed in the light-current curves for active-active coupled resonator devices. This bistability can be used for high contrast switching with contrast ratios as high as 100:1. Coupled-resonator vertical-cavity lasers have shown enhanced mode selectivity which has allowed devices to lase with fundamental-mode output powers as high as 5.2 mW.

  15. Age Prejudice of 'Act Your Age.'

    Science.gov (United States)

    Ponzo, Zander

    1978-01-01

    Many life-style decisions are often adversely influenced by prejudicial attitudes, norms, and laws about age. The relationship between ways of thinking about developmental tasks and age prejudice is discussed. (Author)

  16. Advances in magnetic and optical resonance

    CERN Document Server

    Warren, Warren S

    1997-01-01

    Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.

  17. Super-Resonant Intracavity Coherent Absorption

    CERN Document Server

    Malara, P; Giorgini, A; Avino, S; De Natale, P; Gagliardi, G

    2016-01-01

    The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption. We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot-ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy...

  18. Classical and quantum resonances for hyperbolic surfaces

    OpenAIRE

    Guillarmou, Colin; Hilgert, Joachim; Weich, Tobias

    2016-01-01

    For compact and for convex co-compact oriented hyperbolic surfaces, we prove an explicit correspondence between classical Ruelle resonant states and quantum resonant states, except at negative integers where the correspondence involves holomorphic sections of line bundles.

  19. Optical resonance of metal-coated nanoshell

    Institute of Scientific and Technical Information of China (English)

    Diao Jia-Jie(刁佳杰); Chen Guang-De(陈光德); Xi Cong(席聪); Z Y Fan; Yuan Jin-She(苑进社)

    2003-01-01

    Metal-coated nanoshell, the nanoparticle consisting of a nanometre-scale dielectric core coated with a thin metallic shell, exhibits three distinct optical resonant forms, the sphere cavity resonance (SCR), plasmon resonance (PR), and concentric dielectric sphere resonance (CDSR). The SCR, PR and CDSR of the metal-coated nanoshell reveal a geometric tunability controlled by the core radius and by the ratio of the core radius to the total radius. Classical electrodynamics and Mie scattering theory are used to treat the resonant forms and the transition state between the resonant forms. Based on previous experimental research, we present a group of resonant equations for all the resonant forms, which depend on the geometric structure of the metal-coated nanoshell.

  20. Old age psychiatry in the modern age.

    Science.gov (United States)

    Warner, James P

    2015-11-01

    Old age psychiatry services globally are under threat. The discipline enjoyed its heyday in the two decades bridging the millennium. More recently there has been a move to integrate old age services with those of working age adults, to create 'ageless' services. Evidence is beginning to accumulate that this is a bad idea.

  1. Facial Age Estimation with Age Difference.

    Science.gov (United States)

    Hu, Zhenzhen; Wen, Yonggang; Wang, Jianfeng; Wang, Meng; Hong, Richang; Yan, Shuicheng

    2016-12-01

    Age estimation based on the human face remains a significant problem in computer vision and pattern recognition. In order to estimate an accurate age or age group of a facial image, most of the existing algorithms require a huge face data set attached with age labels. This imposes a constraint on the utilization of the immensely unlabeled or weakly labeled training data, e.g. the huge amount of human photos in the social networks. These images may provide no age label, but it is easily to derive the age difference for an image pair of the same person. To improve the age estimation accuracy, we propose a novel learning scheme to take advantage of these weakly labeled data via the deep Convolutional Neural Networks (CNNs). For each image pair, Kullback-Leibler divergence is employed to embed the age difference information. The entropy loss and the cross entropy loss are adaptively applied on each image to make the distribution exhibit a single peak value. The combination of these losses is designed to drive the neural network to understand the age gradually from only the age difference information. We also contribute a dataset including more than one hundred thousand face images attached with their taken dates. Each image is both labeled with the timestamp and people identity. Experimental results on two aging face databases show the advantages of the proposed age difference learning system and the state-of-the-art performance is gained.

  2. Avoiding Aging? Social Psychology's Treatment of Age

    Science.gov (United States)

    Barrett, Anne E.; Redmond, Rebecca; von Rohr, Carmen

    2012-01-01

    Population aging, in conjunction with social and cultural transformations of the life course, has profound implications for social systems--from large-scale structures to micro-level processes. However, much of sociology remains fairly quiet on issues of age and aging, including the subfield of social psychology that could illuminate the impact of…

  3. Spatially coherent surface resonance states derived from magnetic resonances

    CERN Document Server

    Wei, Zeyong; Cao, Yang; Wu, Chao; Ren, Jinzhi; Hang, Zhihong; Chen, Hong; Zhang, Daozhong; Chan, C T

    2010-01-01

    A thin metamaterial slab comprising a dielectric spacer sandwiched between a metallic grating and a ground plane is shown to possess spatially coherent surface resonance states that span a large frequency range and can be tuned by structural and material parameters. They give rise to nearly perfect angle-selective absorption and thus exhibit directional thermal emissivity. Direct numerical simulations show that the metamaterial slab supports spatially coherent thermal emission in a wide frequency range that is robust against structural disorder.

  4. Chaos in Mean Motion Resonances of the Kuiper Belt

    CERN Document Server

    Franklin, Fred

    2014-01-01

    In this paper on mean motion resonances in the Kuiper belt we consider effects on resonant bodies captured in an earlier migration by determining levels of chaos as a function of eccentricity, e, at the most stable orbital configuration. We find the the maximum observed e's at resonance very closely correspond to orbits with Lyapunov times ~ 1000 orbital periods of Neptune--much the same number as applies in the asteroid belt with Neptune's period replaced by Jupiter's. The fact that this number caps the e's of markedly chaotic but still existing bodies, implies that the great majority of escapes at equal and larger e's have already occurred. Yet escapes must continue at some level if the small population in the outermost belt is to be maintained because typical lifetimes of bodies there are only ~ 1/10 of the solar system's age. A study of stability at resonance also reinforces the claim that the post-migration boundary of the inner Kuiper belt lies near 34 AU and that the primordial, or pre-migration, outer...

  5. Theory of atomic motion in resonant radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cook, R.J.

    1980-03-01

    Atomic motion in resonant and near resonant electromagnetic radiation is investigated theoretically. The exposition begins with a study of atomic motion in a resonant standing light wave, with a view toward isotope separation by selective photodeflection, and proceeds to the investigation of more general problems of atomic motion in resonant radiation. The body of the work consists of six chapters, each of which was prepared as a manuscript for publication in the open literature.

  6. Regeneration of ZVS converter with Resonant inductor

    Directory of Open Access Journals (Sweden)

    J.Sivavara Prasad

    2011-09-01

    Full Text Available This paper presents an analysis of the regeneration of zero-voltage-switching converter with resonant inductor, quasi-resonant converters, and full-bridge zero-voltage-switched PWM Converter. The design of a clamping circuit considering a saturable resonant inductor is presented and compared with the design of a clamping circuit with a linear resonant inductor. A diode model with reverse recovery is employed to simulate the effects.

  7. Nonlinear Thermal Compensators for WGM Resonators

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute; Yu, Nan; Iltchenko, Vladimir

    2009-01-01

    In an alternative version of a proposed bimaterial thermal compensator for a whispering-gallery-mode (WGM) optical resonator, a mechanical element having nonlinear stiffness would be added to enable stabilization of a desired resonance frequency at a suitable fixed working temperature. The previous version was described in "Bimaterial Thermal Compensators for WGM Resonators." Both versions are intended to serve as inexpensive means of preventing (to first order) or reducing temperature-related changes in resonance frequencies.

  8. Electrically Tunable Plasmonic Resonances with Graphene

    DEFF Research Database (Denmark)

    Emani, Naresh K.; Chung, Ting-Fung; Ni, Xingjie

    2012-01-01

    Real time switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy and sensing. We take advantage of electrically tunable interband transitions in graphene to control the strength of the plasmonic resonance.......Real time switching of a plasmonic resonance may find numerous applications in subwavelength optoelectronics, spectroscopy and sensing. We take advantage of electrically tunable interband transitions in graphene to control the strength of the plasmonic resonance....

  9. Study of resonance in wind parks

    OpenAIRE

    Monjo, Lluis; Sainz, Luis; Liang, Jun; Pedra, Joaquín

    2015-01-01

    Wind turbine harmonic current emissions are a well-known power quality problem. These emissions flow through wind park impedances, leading to grid voltage distortion. Parallel resonance may worsen the problem because it increases voltage distortion around the resonance frequency. Hence, it is interesting to analyze the parallel resonance phenomenon. The paper explores this phenomenon in wind parks and provides analytical expressions to determine parallel resonances. (C) 2015 The Authors. Publ...

  10. Parametric resonance in neutrino oscillations in matter

    Indian Academy of Sciences (India)

    E Kh Akhmedov

    2000-01-01

    Neutrino oscillations in matter can exhibit a specific resonance enhancement - parametric resonance, which is different from the MSW resonance. Oscillations of atmospheric and solar neutrinos inside the earth can undergo parametric enhancement when neutrino trajectories cross the core of the earth. In this paper we review the parametric resonance of neutrino oscillations in matter. In particular, physical interpretation of the effect and the prospects of its experimental observation in oscillations of solar and atmospheric neutrinos in the earth are discussed.

  11. Electromagnetic Transmission Through Resonant Structures

    Science.gov (United States)

    Young, Steven M.

    Electromagnetic resonators store energy in the form of oscillatory electric and magnetic fields and gradually exchange that energy by coupling with their environment. This coupling process can have profound effects on the transmission and reflection properties of nearby interfaces, with rapid transitions from high transmittance to high reflectance over narrow frequency ranges, and has been exploited to design useful optical components such as spectral filters and dielectric mirrors. This dissertation includes analytic, numeric, and experimental investigations of three different electromagnetic resonators, each based on a different method of confining electromagnetic fields near the region of interest. First, we show that a structure with two parallel conducting plates, each containing a subwavelength slit, supports a localized resonant mode bound to the slits and therefore exhibits (in the absence of nonradiative losses), perfect resonant transmission over a narrow frequency range. In practice, the transmission is limited by conduction losses in the sidewalls; nevertheless, experimental results at 10 GHz show a narrowband transmission enhancement by a factor of 104 compared to the non-resonant transmission, with quality factor (ratio of frequency to peak width) Q ~ 3000. Second, we describe a narrowband transmission filter based on a single-layer dielectric grating. We use a group theory analysis to show that, due to their symmetry, several of the grating modes cannot couple to light at normal incidence, while several others have extremely large coupling. We then show how selectively breaking the system symmetry using off-normal light incidence can produce transmission peaks by enabling weak coupling to some of the previously protected modes. The narrowband filtering capabilities are validated by an experimental demonstration in the long wavelength infrared, showing transmission peaks of quality factor Q ~ 100 within a free-spectral range of 8-15 mum. Third, we

  12. Relationship between Fermi Resonance and Solvent Effects

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiu-Lan; LI Dong-Fei; SUN Cheng-Lin; LI Zhan-Long; YANG Guang; ZHOU Mi; LI Zuo-Wei; GAO Shu-Qin

    2011-01-01

    We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations. Also, we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures. It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio, etc., on the other hand, the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.%@@ We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations.Also,we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures.It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio,etc.,on the other hand,the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.

  13. Metamaterial localized resonance sensors: prospects and limitations

    DEFF Research Database (Denmark)

    Jeppesen, Claus; Xiao, Sanshui; Mortensen, Asger;

    2010-01-01

    The prospects and limitations of metamaterial localized resonance sensors are investigated theoretically and experimentally. Gold split-ring resonators are employed as the model system where the light induced LC-resonance yields a figure-of-merit, sensitivity divided by linewidth, up to 54 depend...

  14. Saturating optical resonances in quantum dots

    Science.gov (United States)

    Nair, Selvakumar V.; Rustagi, K. C.

    Optical bistability in quantum dots, recently proposed by Chemla and Miller, is studied in a two-resonance model. We show that for such classical electromagnetic resonances the applicability of a two-resonance model is far more restrictive than for those in atoms.

  15. A Family of Resonant Vibration Control Formats

    DEFF Research Database (Denmark)

    Krenk, Steen; Høgsberg, Jan Becker

    Resonant control makes use of a controller with a resonance frequency and an equivalent damping ratio. A simple explicit calibration procedure is presented for a family of resonant controllers in which the frequency is tuned to the natural frequency of the targeted mode in such a way that the two...

  16. Progress Toward Understanding Baryon Resonances

    CERN Document Server

    Crede, Volker

    2013-01-01

    The composite nature of baryons manifests itself in the existence of a rich spectrum of excited states, in particular in the important mass region 1-2 GeV for the light-flavoured baryons. The properties of these resonances can be identified by systematic investigations using electromagnetic and strong probes, primarily with beams of electrons, photons, and pions. After decades of research, the fundamental degrees of freedom underlying the baryon excitation spectrum are still poorly understood. The search for hitherto undiscovered but predicted resonances continues at many laboratories around the world. Recent results from photo- and electroproduction experiments provide intriguing indications for new states and shed light on the structure of some of the known nucleon excitations. The continuing study of available data sets with consideration of new observables and improved analysis tools have also called into question some of the earlier findings in baryon spectroscopy. Other breakthrough measurements have be...

  17. Soliton crystals in Kerr resonators

    CERN Document Server

    Cole, Daniel C; Del'Haye, Pascal; Diddams, Scott A; Papp, Scott B

    2016-01-01

    Solitons are pulses that propagate without spreading due to a balance between nonlinearity and dispersion (or diffraction), and are universal features of systems exhibiting these effects. Solitons play an important role in plasma physics, fluid dynamics, atomic physics, biology, and optics. In the context of integrated photonics, bright dissipative cavity solitons in Kerr-nonlinear resonators are envisioned to play an important role in next-generation communication, computation, and measurement systems. Here we report the discovery of soliton crystals in Kerr resonators-collectively ordered ensembles of co-propagating solitons with discrete allowed temporal separations. Through analysis of optical spectra, we identify a complicated but discrete space of interacting soliton configurations, including crystals exhibiting vacancies (Schottky defects), shifted pulses (Frenkel defects), and superstructure. Time-domain characterization of the output-coupled soliton pulse train directly confirms our inference of the ...

  18. Optical antennas as nanoscale resonators.

    Science.gov (United States)

    Agio, Mario

    2012-02-07

    Recent progress in nanotechnology has enabled us to fabricate sub-wavelength architectures that function as antennas for improving the exchange of optical energy with nanoscale matter. We describe the main features of optical antennas for enhancing quantum emitters and review the designs that increase the spontaneous emission rate by orders of magnitude from the ultraviolet up to the near-infrared spectral range. To further explore how optical antennas may lead to unprecedented regimes of light-matter interactions, we draw a relationship between metal nanoparticles, radio-wave antennas and optical resonators. Our analysis points out how optical antennas may function as nanoscale resonators and how these may offer unique opportunities with respect to state-of-the-art microcavities.

  19. Resonantly enhanced filamentation in gases

    CERN Document Server

    Doussot, J; Billard, F; Béjot, P; Faucher, O

    2016-01-01

    In this Letter, a low-loss Kerr-driven optical filament in Krypton gas is experimentally reported in the ultraviolet. The experimental findings are supported by ab initio quantum calculations describing the atomic optical response. Higher-order Kerr effect induced by three-photon resonant transitions is identified as the underlying physical mechanism responsible for the intensity stabilization during the filamentation process, while ionization plays only a minor role. This result goes beyond the commonly-admitted paradigm of filamentation, in which ionization is a necessary condition of the filament intensity clamping. At resonance, it is also experimentally demonstrated that the filament length is greatly extended because of a strong decrease of the optical losses.

  20. Resonant spectra of quadrupolar anions

    CERN Document Server

    Fossez, K; Nazarewicz, W; Michel, N; Garrett, W R; Płoszajczak, M

    2016-01-01

    In quadrupole-bound anions, an extra electron is attached at a sufficiently large quadrupole moment of a neutral molecule, which is lacking a permanent dipole moment. The nature of the bound states and low-lying resonances of such anions is of interest for understanding the threshold behavior of open quantum systems in general. In this work, we investigate the properties of quadrupolar anions as extreme halo systems, the formation of rotational bands, and the transition from a subcritical to supercritical electric quadrupole moment. We solve the electron-plus-molecule problem using a non-adiabatic coupled-channel formalism by employing the Berggren ensemble, which explicitly contains bound states, narrow resonances, and the scattering continuum. We demonstrate that binding energies and radii of quadrupolar anions strictly follow the scaling laws for two-body halo systems. Contrary to the case of dipolar anions, ground-state band of quadrupolar anions smoothly extend into the continuum, and many rotational ban...

  1. Optical antennas as nanoscale resonators

    CERN Document Server

    Agio, Mario

    2011-01-01

    Recent progress in nanotechnology has enabled us to fabricate subwavelength architectures that function as antennas for improving the exchange of optical energy with nanoscale matter. We describe the main features of optical antennas for enhancing quantum emitters and review designs that increase the spontaneous emission rate by orders of magnitude from the ultraviolet up to the near-infrared spectral range. To further explore how optical antennas may lead to unprecedented regimes of light-matter interaction, we draw a relationship between metal nanoparticles, radio-wave antennas and optical resonators. Our analysis points out how optical antennas may function as nanoscale resonators and how these may offer unique opportunities with respect to state-of-the-art microcavities.

  2. Dynamic control of chaotic resonators

    KAUST Repository

    Di Falco, A.

    2016-02-16

    We report on the all-optical control of chaotic optical resonators based on silicon on insulator (SOI) platform. We show that simple non-chaotic cavities can be tuned to exhibit chaotic behavior via intense optical pump- ing, inducing a local change of refractive index. To this extent we have fabricated a number of devices and demonstrated experimentally and theoretically that chaos can be triggered on demand on an optical chip. © 2016 SPIE.

  3. Formation time of hadronic resonances

    Directory of Open Access Journals (Sweden)

    Vitev Ivan

    2012-11-01

    Full Text Available In heavy-ion collisions, formation time of hadrons of high transverse momentum can play a pivotal role in determining the perturbative dynamics of the final-state parton and particle system. We present methods to evaluate the formation times of light hadrons, hadronic resonances, open heavy flavor and quarkonia. Experimental implications of the short formation times of heavy particles are discussed in light of recent RHIC and LHC data.

  4. Automated Nuclear Quadruple Resonance Spectrometer

    Directory of Open Access Journals (Sweden)

    IVANCHUK, M.

    2008-06-01

    Full Text Available Improvement of an autodyne Nuclear quadruple resonance spectrometer is offered. The change of frequency of oscillatory LC circuit of the spectrometer is carried out in two ways: by varicap and variable capacitor. A processor module for the capacitor and varicap control is developed. The unit allows to scan and measure the level and frequency of the NQR-signal. The unit is controlled by the personal computer.

  5. Strange decays from strange resonances

    CERN Document Server

    Bijker, R

    2001-01-01

    We discuss the mass spectrum and strong decays of baryon resonances belonging to the N, Delta, Sigma, Lambda, Xi and Omega families in a collective string-like model for the nucleon. We find good overall agreement with the available data. Systematic discrepancies are found for lowlying S-wave states, in particular in the strong decays of N(1535), N(1650), Sigma(1750), Lambda(1405), Lambda(1670) and Lambda(1800).

  6. Strange decays from strange resonances

    Energy Technology Data Exchange (ETDEWEB)

    Bijker, R. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F. (Mexico); Leviatan, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

    2001-07-01

    We discuss the mass spectrum and strong decays of baryon resonances belonging to the N, {delta}, {sigma}, {lambda}, {xi} and {omega} families in a collective string- like model for the nucleon. We find good overall agreement with the available data. Systematic discrepancies are found for low-lying S-wave states, in particular in the strong decays of N(1535), N(1650), {sigma}(1750), {lambda}{sup *}(1405), {lambda}(1670) and {lambda}(1800). (Author)

  7. Nucleon Resonance Transition Form factors

    Energy Technology Data Exchange (ETDEWEB)

    Burkert, Volker D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Mokeev, Viktor I. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Aznauryan, Inna G. [Yerevan Physics Inst. (YerPhI) (Armenia)

    2016-08-01

    We discuss recent results from CLAS on electromagnetic resonance transition amplitudes and their dependence on the distance scale (Q2). From the comparison of these results with most advanced theoretical calculations within QCD-based approaches there is clear evidence that meson-baryon contributions are present and important at large distances, i.e. small Q2, and that quark core contributions dominate the short distance behavior.

  8. Automated Nuclear Quadruple Resonance Spectrometer

    OpenAIRE

    2008-01-01

    Improvement of an autodyne Nuclear quadruple resonance spectrometer is offered. The change of frequency of oscillatory LC circuit of the spectrometer is carried out in two ways: by varicap and variable capacitor. A processor module for the capacitor and varicap control is developed. The unit allows to scan and measure the level and frequency of the NQR-signal. The unit is controlled by the personal computer.

  9. Magnetoacoustic resonance in magnetoelectric bilayers

    Science.gov (United States)

    Filippov, D. A.; Bichurin, M. I.; Petrov, V. M.; Srinivasan, G.

    2004-03-01

    Layered composites of ferrite and ferroelectric single crystal thin films are of interest for studies on magnetoelectric interactions [1,2]. Such interactions result in unique and novel effects that are absent in single phase materials. For example, in a single crystal composite it is possible to control the ferromagnetic resonance (FMR) parameters for the ferrite by means of hypersonic oscillations induced in the ferroelectric phase. The absorption of acoustic oscillations by the ferrite results in variation in FMR line shape and power absorbed. One anticipates resonance absorption of elastic waves when the frequency of elastic waves coincides with the precession frequency of magnetization vector. This work is concerned with the nature of FMR under the influence of acoustic oscillations with the same frequency as FMR. Bilayers of ferrite and piezoelectric single crystals are considered. Hypersonic waves induced in the piezoelectric phase transmit acoustic power into ferrite due to mechanical connectivity between the phases. That transmission depends strongly on interface coupling [3]. We estimate the resulting variations in ferromagnetic resonance line shape. Estimates of magnetoelectric effect at magnetoacoustic resonance are also given. In addition, dependence of absorption of acoustic power on sample dimensions and compliances, electric and magnetic susceptibilities, piezoelectric and magnetostriction coefficients is discussed. The theory provided here is important for an understanding of interface coupling and the nature of magnetoelastic interactions in the composites. 1. M. I. Bichurin and V. M. Petrov, Zh. Tekh. Fiz. 58, 2277 (1988) [Sov. Phys. Tech. Phys. 33, 1389 (1988)]. 2. M.I. Bichurin, I. A. Kornev, V. M. Petrov, A. S. Tatarenko, Yu. V. Kiliba, and G. Srinivasan. Phys. Rev. B 64, 094409 (2001). 3. M. I. Bichurin, V. M. Petrov, and G. Srinivasan, J. Appl. Phys. 92, 7681 (2002). This work was supported by grants from the Russian Ministry of Education (

  10. Proton Resonance Spectroscopy -- Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, Jr, J F

    2009-07-27

    This report summarizes work supported by the DOE Grant DE-FG02-96ER40990 during its duration from June 1996 to May 2009. Topics studied include (1) statistical descriptions of nuclear levels and measurements of proton resonances relevant to such descriptions, including measurements toward a complete level scheme for 30P, (2) the development of methods to estimate the missing fraction of levels in a given measurement, and (3) measurements at HRIBF relevant to nuclear astrophysics.

  11. Capacitance of circular patch resonator

    Energy Technology Data Exchange (ETDEWEB)

    Miano, G.; Verolino, L. [Dip. di Ingegneria Elettrica, Ist. Nazionale di Fisica Nucleare, Naples (Italy); Panariello, G. [Dip. di Ingegneria Elettronica, Naples (Italy); Vaccaro, V.G. [Ist. Nazionale di Fisica Nucleare, Naples (Italy). Dipt. di Scienze Fisiche

    1995-11-01

    In this paper the capacitance of the circular microstrip patch resonator is computed. It is shown that the electrostatic problem can be formulated as a system of dual integral equations, and the most interesting techniques of solutions of these systems are reviewed. Some useful approximated formulas for the capacitance are derived and plots of the capacitance are finally given in a wide range of dielectric constants.

  12. In operando Detection of Three-Way Catalyst Aging by a Microwave-Based Method: Initial Studies

    Directory of Open Access Journals (Sweden)

    Gregor Beulertz

    2015-07-01

    Full Text Available Initial studies on aging detection of three way catalysts with a microwave cavity perturbation method were conducted. Two physico-chemical effects correlate with the aging state. At high temperatures, the resonance frequencies for oxidized catalysts (λ = 1.02 are not influenced by aging, but are significantly affected by aging in the reduced case (λ = 0.98. The catalyst aging state can therefore potentially be inferred from the resonance frequency differences between reduced and oxidized states or from the resonance frequency amplitudes during lambda oscillations. Secondly, adsorbed water at low temperatures strongly affects the resonance frequencies. Light-off experiment studies showed that the resonance frequency depends on the aging state at temperatures below the oxygen storage light-off. These differences were attributed to different water sorption capabilities of differently aged samples due to a surface area decrease with proceeding aging. In addition to the aging state, the water content in the feed gas and the temperature affect the amount of adsorbed water, leading to different integral electrical material properties of the catalyst and changing the resonance properties of the catalyst-filled canning. The classical aging-related properties of the catalyst (oxygen storage capacity, oxygen storage light-off, surface area, agreed very well with data obtained by the microwave-based method.

  13. Exercise and age

    Science.gov (United States)

    ... It is never too late to start exercising. Exercise has benefits at any age. Don't worry if you ... to tie your shoes Alternative Names Age and exercise Images Benefit of regular exercise Flexibility exercise Exercise and age ...

  14. National Council on Aging

    Science.gov (United States)

    ... Centers Center for Benefits Access Center for Healthy Aging Donate Skip to Content a A Menu Economic ... Seniors Home Equity Older Workers Money Management Healthy Aging Falls Prevention Chronic Disease Management Flu + You Aging ...

  15. Administration on Aging

    Science.gov (United States)

    ... Federal Initiatives Career Opportunities Contact Us Administration on Aging (AoA) The Administration on Aging (AOA) is the ... themselves. Back to top Older Americans Act and Aging Network To meet the diverse needs of the ...

  16. Sleep and Aging: Insomnia

    Science.gov (United States)

    ... Aging Insomnia Insomnia is the most common sleep complaint at any age. It affects almost half of ... A-Z | videos A-Z | training | about us | Customer Support | site map National Institute on Aging | U.S. ...

  17. Pregnancy After Age 35

    Science.gov (United States)

    ... Pregnancy complications > Pregnancy after age 35 Pregnancy after age 35 E-mail to a friend Please fill ... to your dashboard . KEY POINTS Being pregnant after age 35 makes certain complications more likely, including premature ...

  18. Vector-Resonance-Multimode Instability

    Science.gov (United States)

    Sergeyev, S. V.; Kbashi, H.; Tarasov, N.; Loiko, Yu.; Kolpakov, S. A.

    2017-01-01

    The modulation and multimode instabilities are the main mechanisms which drive spontaneous spatial and temporal pattern formation in a vast number of nonlinear systems ranging from biology to laser physics. Using an Er-doped fiber laser as a test bed, here for the first time we demonstrate both experimentally and theoretically a new type of a low-threshold vector-resonance-multimode instability which inherits features of multimode and modulation instabilities. The same as for the multimode instability, a large number of longitudinal modes can be excited without mode synchronization. To enable modulation instability, we modulate the state of polarization of the lasing signal with the period of the beat length by an adjustment of the in-cavity birefringence and the state of polarization of the pump wave. As a result, we show the regime's tunability from complex oscillatory to periodic with longitudinal mode synchronization in the case of resonance matching between the beat and cavity lengths. Apart from the interest in laser physics for unlocking the tunability and stability of dynamic regimes, the proposed mechanism of the vector-resonance-multimode instability can be of fundamental interest for the nonlinear dynamics of various distributed systems.

  19. Traces of a triboson resonance

    Science.gov (United States)

    Aguilar-Saavedra, J. A.; Collins, J. H.; Lombardo, S.

    2016-09-01

    We show that the relatively small but coincident excesses observed around 2 TeV in the ATLAS Run 1 and Run 2 hadronic diboson searches — when a cut on the number of tracks in the fat jets is not applied — and the null results of all remaining high-mass diboson searches are compatible with the decay of a triboson resonance R into WZ plus an extra particle X. These decays can take place via new neutral ( Y 0) or charged ( Y ±) particles, namely R → Y 0 W, with Y 0 → ZX, or R → Y ± Z, with Y ± → WX. An obvious candidate for such intermediate particle is a neutral one Y 0, given a 3 .9 σ excess found at 650 GeV by the CMS Collaboration in searches for intermediate mass diboson resonances decaying to ZV, with V = W, Z. We discuss discovery strategies for triboson resonances with small modifications of existing hadronic searches.

  20. On the new LHC resonance

    CERN Document Server

    Cea, Paolo

    2016-01-01

    We present an alternative interpretation within the Standard Model of the new LHC resonance at $125 \\; GeV$. We further elaborate on our previous proposal that the resonance at 125 GeV could be interpreted as a pseudoscalar meson with quantum number $J^{PC} = 0^{- +}$. We develop a phenomenological approach where this pseudoscalar mimics the decays of the Standard Model Higgs boson in the vector boson decay channels. We propose that the true Higgs boson should be a heavy resonance with mass of $750 \\, GeV$ as argued in Ref.~\\cite{Cea:2012}. We determine the most relevant decay modes and estimate the partial decay widths and branching ratios. We also discuss briefly the experimental signatures of this heavy Higgs boson. Finally, we attempt a comparison of our theoretical expectations with recent data at $\\sqrt{s} =13 \\,TeV$ from ATLAS and CMS experiments in the so-called golden channel. We find that the available experimental data could be consistent with the heavy Higgs scenario.

  1. eta Photoproduction and N* resonances

    CERN Document Server

    Choi, Ki-Seok; Hosaka, Atsushi; Kim, Hyun-Chul

    2007-01-01

    We investigate the eta photoproduction from the nucleon using the effective Lagrangian approach at tree level. We focus on the nucleon resonance N*(1675) of possibly exotic nature, which was reported by the GRAAL, Tohoku LNS and CB-ELSA examining its spin and parity theoretically. In addition, we consider six nucleon resonances, D_{13}(1520), S_{11}(1535), S_{11}(1650), D_{15}(1675), P_{11}(1710), P_{13}(1720) as well as possible background contributions. We calculate the differential cross sections and beam asymmetries for the neutron and proton targets. They indicate that there is isospin asymmetry which can be interpreted as the large difference in the the transition photon couplings: mu_{gamma p p*} << mu_{gamma n n*}. Moreover, we find that the spin-1/2 state is preferred in order to reproduce the experimental data, although its parity remains undetermined. This observation implies that the new resonance may be identified as a non-strangeness member of the baryon antidecuplet.

  2. Traces of a triboson resonance

    CERN Document Server

    Aguilar-Saavedra, J A; Lombardo, S

    2016-01-01

    We show that the relatively small but coincident excesses observed around 2 TeV in the ATLAS Run 1 and Run 2 hadronic diboson searches --- when a cut on the number of tracks in the fat jets is not applied --- and the null results of all remaining high-mass diboson searches are compatible with the decay of a triboson resonance $R$ into $WZ$ plus an extra particle $X$. These decays can take place via new neutral ($Y^0$) or charged ($Y^\\pm$) particles, namely $R \\to Y^0 \\, W$, with $Y^0 \\to Z X$, or $R \\to Y^\\pm Z$, with $Y^\\pm \\to W X$. An obvious candidate for such intermediate particle is a neutral one $Y^0$, given a $3.9\\sigma$ excess found at 650 GeV by the CMS Collaboration in searches for intermediate mass diboson resonances decaying to $ZV$, with $V=W,Z$. We discuss discovery strategies for triboson resonances with small modifications of existing hadronic searches.

  3. Diphoton resonance confronts dark matter

    Science.gov (United States)

    Choi, Soo-Min; Kang, Yoo-Jin; Lee, Hyun Min

    2016-07-01

    As an interpretation of the 750 GeV diphoton excesses recently reported by both ATLAS and CMS collaborations, we consider a simple extension of the Standard Model with a Dirac fermion dark matter where a singlet complex scalar field mediates between dark matter and SM particles via effective couplings to SM gauge bosons and/or Higgs-portal. In this model, we can accommodate the diphoton events through the direct and/or cascade decays of pseudo-scalar and real scalar partners of the complex scalar field. We show that mono-jet searches and gamma-ray observations are complementary in constraining the region where the width of the diphoton resonance can be enhanced due to the couplings of the resonance to dark matter and the correct relic density is obtained. In the case of cascade decay of the resonance, the effective couplings of singlet scalars can be smaller, but the model is still testable by the future discrimination between single photon and photon-jet at the LHC as well as the gamma-ray searches for the cascade annihilation of dark matter.

  4. Diphoton resonance confronts dark matter

    CERN Document Server

    Choi, Soo-Min; Lee, Hyun Min

    2016-01-01

    As an interpretation of the 750 GeV diphoton excesses recently reported by both ATLAS and CMS collaborations, we consider a simple extension of the Standard Model with a Dirac fermion dark matter where a singlet complex scalar field mediates between dark matter and SM particles via effective couplings to SM gauge bosons and/or Higgs-portal. In this model, we can accommodate the diphoton events through the direct and/or cascade decays of pseudo-scalar and real scalar partners of the complex scalar field. We show that mono-jet searches and gamma-ray observations are complementary in constraining the region where the width of the diphoton resonance can be enhanced due to the couplings of the resonance to dark matter and the correct relic density is obtained. In the case of cascade decay of the resonance, the effective couplings of singlet scalars can be smaller, but the model is still testable by the future discrimination between single photon and photon-jet at the LHC as well as the gamma-ray searches for the c...

  5. Nutrients, Microglia Aging, and Brain Aging.

    Science.gov (United States)

    Wu, Zhou; Yu, Janchun; Zhu, Aiqin; Nakanishi, Hiroshi

    2016-01-01

    As the life expectancy continues to increase, the cognitive decline associated with Alzheimer's disease (AD) becomes a big major issue in the world. After cellular activation upon systemic inflammation, microglia, the resident immune cells in the brain, start to release proinflammatory mediators to trigger neuroinflammation. We have found that chronic systemic inflammatory challenges induce differential age-dependent microglial responses, which are in line with the impairment of learning and memory, even in middle-aged animals. We thus raise the concept of "microglia aging." This concept is based on the fact that microglia are the key contributor to the acceleration of cognitive decline, which is the major sign of brain aging. On the other hand, inflammation induces oxidative stress and DNA damage, which leads to the overproduction of reactive oxygen species by the numerous types of cells, including macrophages and microglia. Oxidative stress-damaged cells successively produce larger amounts of inflammatory mediators to promote microglia aging. Nutrients are necessary for maintaining general health, including the health of brain. The intake of antioxidant nutrients reduces both systemic inflammation and neuroinflammation and thus reduces cognitive decline during aging. We herein review our microglia aging concept and discuss systemic inflammation and microglia aging. We propose that a nutritional approach to controlling microglia aging will open a new window for healthy brain aging.

  6. Distributed optical fiber surface plasmon resonance sensors

    Institute of Scientific and Technical Information of China (English)

    Zhenxin Cao; Lenan Wu; Dayong Li

    2006-01-01

    @@ The relationships of the resonant wavelength of optical fiber surface plasmon resonance (SPR) sensors to the modulation layer refractive index, thickness and the refractive index of the bulk medium are obtained by using theoretical calculation model of optical fiber SPR sensors under certain conditions, which indicates that resonant wavelength of the sensors is approximately linear with modulation layer thickness. Based on the linear relationship, multiple SPR sensors with different resonant wavelengths can be fabricated in a single optical fiber named as distributed optical fiber surface plasmon resonance sensors (DOFSPRSs).Experimental results are presented, showing that it is practical to fabricate more than one SPR sensors in a single optical fiber.

  7. Spatial filtering with surface plasmon resonance systems

    Science.gov (United States)

    Ghosh, A. K.; Siddharth, V.; Bhagat, M.; Aggarwal, S.; Anurag, P.; Jain, M.

    2007-09-01

    Surface plasmon resonance based sensors are most useful in measuring the refractive indices of biochemicals. In such sensors a beam of light obliquely incident at an interface of glass and metallic thin film excites resonant plasmon waves in the metal if the angle of incidence or the wavelength is selected properly. The resonance conditions are changed by the refractive indices of any material in contact with the metal film. When resonance occurs the light beam is absorbed strongly. We can easily show that the phenomenon of surface plasmon resonance in such a system acts as a high quality spatial notch or band rejection filter.

  8. Observation of a Hybrid Spin Resonance

    Science.gov (United States)

    Bai, M.; Allgower, C.; Ahrens, L.; Alessi, J.; Brown, K.; Bunce, G.; Cameron, P.; Chu, C. M.; Courant, E. D.; Glenn, J. W.; Huang, H.; Jeon, D.; Kponou, A. E.; Krueger, K.; Luccio, A.; Makdisi, Y. I.; Lee, S. Y.; Ratner, L.; Reece, K.; Roser, T.; Spinka, H.; Syphers, M. J.; Tsoupas, N.; Underwood, D. G.; van Asselt, W.; Williams, N.; Yokosawa, A.

    2000-02-01

    A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This ``hybrid'' spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors.

  9. The 4:1 resonance (spiral galaxies)

    CERN Document Server

    Contopoulos, George

    1981-01-01

    Studies the resonance omega /sub 1/: omega /sub 2/=4:1 and some near- resonance cases. The main peculiarity of this resonance is that for omega /sub 1/: omega /sub 2/<4 the characteristic of the central periodic orbits is broken into two and each part is joined with a resonant characteristic. The behaviour is described theoretically by means of the 'third' integral. It seems that there are infinite families of simple periodic orbits near the escape region. Finally, a comparison is made with the cases near the omega /sub 1/: omega /sub 2 /=2:1 resonance. (8 refs).

  10. Resonant circuit model for efficient metamaterial absorber.

    Science.gov (United States)

    Sellier, Alexandre; Teperik, Tatiana V; de Lustrac, André

    2013-11-04

    The resonant absorption in a planar metamaterial is studied theoretically. We present a simple physical model describing this phenomenon in terms of equivalent resonant circuit. We discuss the role of radiative and dissipative damping of resonant mode supported by a metamaterial in the formation of absorption spectra. We show that the results of rigorous calculations of Maxwell equations can be fully retrieved with simple model describing the system in terms of equivalent resonant circuit. This simple model allows us to explain the total absorption effect observed in the system on a common physical ground by referring it to the impedance matching condition at the resonance.

  11. Equivalent Circuit Model for Thick Split Ring Resonators and Thick Spiral Resonators

    CERN Document Server

    Mancera, Laura Maria Pulido

    2014-01-01

    A simple theoretical model which provides circuit parameters and resonance frequency of metallic thick resonators is presented. Two different topologies were studied: the original Pendry's SRR and spiral resonators of two and three turns. Theoretical computations of resonant frequencies are in good agreement with values obtained with a commercial electromagnetic solver. The model could be helpful for designing thick frequency selective surfaces (FSS) based on this types of resonators, so called metasurfaces.

  12. Effect of metal coating and residual stress on the resonant frequency of MEMS resonators

    OpenAIRE

    Pandey, Ashok Kumar; Venkatesh, KP; Pratap, Rudra

    2009-01-01

    MEMS resonators are designed for a fixed resonant frequency. Therefore, any shift in the resonant frequency of the final fabricated structure can be a denting factor for its suitability towards a desired application. There are numerous factors which alter the designed resonant frequency of the fabricated resonator such as the metal layer deposited on top of the beam and the residual stresses present in the fabricated structure. While the metal coating, which acts as electrode, increases t...

  13. Diffusion and Perfusion Magnetic Resonance Imaging:Fundamentals and Advances

    CERN Document Server

    Assili, Sanam

    2016-01-01

    Over the past few decades, magnetic resonance imaging has been utilized as a powerful imaging modality to evaluate the structure and function of various organs in the human body,such as the brain. Additionally, diffusion and perfusion MR imaging have been increasingly used in neurovascular clinical applications. In diffusion-weighted magnetic resonance imaging, the mobility of water molecules is explored in order to obtain information about the microscopic behavior of the tissues. In contrast, perfusion weighted imaging uses tracers to exploit hemodynamic status, which enables researchers and clinicians to consider this imaging modality as an early biomarker of certain brain diseases. In this review, the fundamentals of physics for diffusion and perfusion MR imaging both of which are highly sensitive to microenvironmental alterations at the cellular level as well as their application in the treatment of aging, Alzheimer's disease, brain tumors and cerebral ischemic injury were discussed.

  14. Extraordinary acoustic transmission mediated by Helmholtz resonators

    Directory of Open Access Journals (Sweden)

    Vijay Koju

    2014-07-01

    Full Text Available We demonstrate perfect transmission of sound through a rigid barrier embedded with Helmholtz resonators. The resonators are confined within a waveguide and they are oriented such that one neck protrudes onto each side of the barrier. Perfect sound transmission occurs even though the open area of the necks is less than 3% of the barrier area. Maximum transmission occurs at the resonant frequency of the Helmholtz resonator. Because the dimensions of the Helmholtz resonators are much smaller than the resonant wavelength, the transmission is independent of the direction of sound on the barrier and of the relative placement of the necks. Further, we show that the transmitted sound experiences a continuous phase transition of π radians as a function of frequency through resonance. In simulations of adjacent resonators with slightly offset resonance frequencies, the phase difference leads to destructive interference. By expanding the simulation to a linear array of tuned Helmholtz resonators we show that it is possible to create an acoustic lens. The ability of Helmholtz resonator arrays to manipulate the phase of a plane acoustic wave enables a new class of sonic beam-forming devices analogous to diffractive optics.

  15. Extraordinary acoustic transmission mediated by Helmholtz resonators

    Science.gov (United States)

    Koju, Vijay; Rowe, Ebony; Robertson, William M.

    2014-07-01

    We demonstrate perfect transmission of sound through a rigid barrier embedded with Helmholtz resonators. The resonators are confined within a waveguide and they are oriented such that one neck protrudes onto each side of the barrier. Perfect sound transmission occurs even though the open area of the necks is less than 3% of the barrier area. Maximum transmission occurs at the resonant frequency of the Helmholtz resonator. Because the dimensions of the Helmholtz resonators are much smaller than the resonant wavelength, the transmission is independent of the direction of sound on the barrier and of the relative placement of the necks. Further, we show that the transmitted sound experiences a continuous phase transition of π radians as a function of frequency through resonance. In simulations of adjacent resonators with slightly offset resonance frequencies, the phase difference leads to destructive interference. By expanding the simulation to a linear array of tuned Helmholtz resonators we show that it is possible to create an acoustic lens. The ability of Helmholtz resonator arrays to manipulate the phase of a plane acoustic wave enables a new class of sonic beam-forming devices analogous to diffractive optics.

  16. Super-Resonant Intracavity Coherent Absorption

    Science.gov (United States)

    Malara, P.; Campanella, C. E.; Giorgini, A.; Avino, S.; de Natale, P.; Gagliardi, G.

    2016-07-01

    The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator’s quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption (CPA). We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot (FP)/ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy and optical sensing schemes.

  17. Compact electric-LC resonators for metamaterials

    CERN Document Server

    Withayachumnankul, Withawat; Abbott, Derek

    2010-01-01

    Alternative designs to an electric-LC (ELC) resonator, which is a type of metamaterial inclusion, are presented in this article. Fitting the resonator with an interdigital capacitor (IDC) helps to increase the total capacitance of the structure. In effect, its resonance frequency is shifted downwards. This implies a decreased overall resonator size with respect to its operating wavelength. As a result, the metamaterial, composed of an array of IDC-loaded ELC resonators with their collective electromagnetic response, possesses improved homogeneity and hence is less influenced by diffraction effects of individual cells. The impact of incorporating an IDC into ELC resonators in terms of the electrical size at resonance and other relevant properties are investigated through both simulation and experiment.

  18. Dielectric square resonator investigated with microwave experiments.

    Science.gov (United States)

    Bittner, S; Bogomolny, E; Dietz, B; Miski-Oglu, M; Richter, A

    2014-11-01

    We present a detailed experimental study of the symmetry properties and the momentum space representation of the field distributions of a dielectric square resonator as well as the comparison with a semiclassical model. The experiments have been performed with a flat ceramic microwave resonator. Both the resonance spectra and the field distributions were measured. The momentum space representations of the latter evidenced that the resonant states are each related to a specific classical torus, leading to the regular structure of the spectrum. Furthermore, they allow for a precise determination of the refractive index. Measurements with different arrangements of the emitting and the receiving antennas were performed and their influence on the symmetry properties of the field distributions was investigated in detail, showing that resonances with specific symmetries can be selected purposefully. In addition, the length spectrum deduced from the measured resonance spectra and the trace formula for the dielectric square resonator are discussed in the framework of the semiclassical model.

  19. Gold nanodisk array surface plasmon resonance sensor

    Science.gov (United States)

    Tian, Xueli

    Surface plasmon resonances in periodic metal nanostructures have been investigated for sensing applications over the last decade. The resonance wavelengths of the nanostructures are usually measured in the transmission or reflection spectrum for chemical and biological sensing. In this thesis, I introduce a nanoscale gap mediated surface plasmon resonance nanodisk array for displacement sensing and a super-period gold nanodisk grating enabled surface plasmon resonance spectrometer sensor. The super-period gold nanodisk grating has a small subwavelength period and a large diffraction grating period. Surface plasmon resonance spectra are measured in the first order diffraction spatial profiles captured by a charge-coupled device (CCD). A surface plasmon resonance sensor for the bovine serum albumin (BSA) protein nanolayer bonding is demonstrated by measuring the surface plasmon resonance shift in the first order diffraction spatial intensity profiles captured by the CCD.

  20. Optical method to differentiate tequilas based on angular modulation surface plasmon resonance

    Science.gov (United States)

    Martínez-López, G.; Luna-Moreno, D.; Monzón-Hernández, D.; Valdivia-Hernández, R.

    2011-06-01

    We report the use of the prism-based surface plasmon resonance (SPR) technique to differentiate between three types of tequilas white or silver, aged, and extra-aged. We used the angular interrogation method in which the structure is based on prism fabricated with BK7 glass coated with a gold layer as the SPR active layer. Our study was centered in the analysis of the resonant angle of the SPR generated by the three types of tequilas produced by the three major tequila-producing firms. We observed that each tequila sample produced a well-differentiated SPR curve. We found that resonant angle of the SPR curve produced by silver tequilas is larger than that produced by the aged and extra-aged tequilas of the same producer firm. We found that the position of the SPR curve is not exclusively determined by the alcohol contents; we believe that there are other parameters derived from the aging process that should be considered. The refractive index of the tequilas used in this study was estimated using the measured resonant angle.

  1. Resonators

    NARCIS (Netherlands)

    Wijnant, Y.H.

    2006-01-01

    For quite a few number of years now, the Structural Dynamics and Acoustics group at the University of Twente studies wave propagation in narrow gaps (e.g. thermal-viscous wave propagation in narrow tubes and thin air layers). The waves propagating in these narrow gaps can be described elegantly by m

  2. Spectral ageing a new age perspective

    CERN Document Server

    Rawlings, S; Rawlings, Katherine M Blundell & Steve

    2002-01-01

    We present an up-to-date critique of the physical basis for the spectral ageing method. We find that the number of cases where this method may be meaningfully applied to deduce the ages of classical double radio sources is small indeed. This critique is much more than merely a re-expression of anxieties about the calibration of spectral ageing (which have been articulated by others in the past).

  3. Resonantly detecting axion-mediated forces with nuclear magnetic resonance.

    Science.gov (United States)

    Arvanitaki, Asimina; Geraci, Andrew A

    2014-10-17

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 10(9) and 10(12) GeV or axion masses between 10(-6) and 10(-3) eV, independent of the cosmic axion abundance.

  4. [Age(ing), ambivalence and mimicry].

    Science.gov (United States)

    Küpper, Thomas

    2016-01-01

    This essay aims to show that the concept of ambivalence could prove especially productive for gerontology. It is known that age(ing) is a category that is characterized by difference and at the same time delineates a process. Ambivalence is eminently suitable for capturing this duality as it enables us to take into account the dynamics peculiar to age(ing) and move beyond those conventional rigid distinctions which fail to grasp key nuances. These theoretical considerations will be put to the test by looking at the so-called young-old and their ambivalent positioning as well as their own mimicry of the middle-agers.

  5. New concept of age(ing: Prospective age

    Directory of Open Access Journals (Sweden)

    Devedžić Mirjana

    2012-01-01

    Full Text Available While the last century was the century of world population growth, according to demographers, the XXI century will be century of population aging. Statistics undoubtedly show that number of elderly will continue it’s growth in the future. If old age is seen as period of life with reduced physical and mental capabilities and increased disability, and demographic aging as increase of dependent population, trends are quite disturbing, at least in certain societal segments. In developed countries, this population category is no longer treated as passive or as a "burden of society" and efforts are made for better social inclusion of older people. In contrast to growing interest in this phenomenon, the concepts that define the aging of the population remained stagnant. The aim of this paper is to introduce into domestic literature the term "prospective age" as a dynamic category which is more affected with socio-historical conditions, not only with biological as traditional definition of aging suggested. Papers written by Sanderson and Scherbov offer new methodological options for study of population aging, because it takes into account the biometric rather than chronological approach. Calculation of prospective years is a simple operation that requires pair of the same number of remained life expectancy from life tables for two different periods (the year of concern is index, and the one we are comparing with is standard year, so that phrase "40s is the new 30s" or "70s the new 60s" gets scientific foundation. Average remaining years of life represent a realistic indicator suggesting increased capacity, activity and vitality of individuals, which is due to accepted demographic parameters still considered old. „Prospective threshold“ is defined as the age when life expectancy falls below 15 years (it is subjective choice made by Sanderson and Scherbov, which is also used in this paper and during the elaboration of these ideas three demographic

  6. Purely electric and magnetic dipole resonances in metamaterial dielectric resonators through perturbation theory inspired geometries

    CERN Document Server

    Campione, Salvatore; Warne, Larry K; Sinclair, Michael B

    2014-01-01

    In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometry in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole ...

  7. Resonant enhancement of Raman scattering in metamaterials with hybrid electromagnetic and plasmonic resonances

    CERN Document Server

    Guddala, Sriram; Ramakrishna, S Anantha

    2016-01-01

    A tri-layer metamaterial perfect absorber of light, consisting of (Al/ZnS/Al) films with the top aluminium layer patterned as an array of circular disk nanoantennas, is investigated for resonantly enhancing Raman scattering from C-60 fullerene molecules deposited on the metamaterial. The metamaterial is designed to have resonant bands due to plasmonic and electromagnetic resonances at the Raman pump frequency (725 nm) as well as Stokes emission bands. The Raman scattering from C60 on the metamaterial with resonantly matched bands is measured to be enhanced by an order of magnitude more than from C60 on metamaterials with off-resonant absorption bands peaked at 1090 nm. The Raman pump is significantly enhanced due to the resonance with a propagating surface plasmon band, while the highly impedance matched electromagnetic resonance is expected to couple out the Raman emission efficiently. The nature and hybridization of the plasmonic and electromagnetic resonances to form compound resonances are investigated by...

  8. Locally Resonant Gaps of Phononic Beams Induced by Periodic Arrays of Resonant Shunts

    Institute of Scientific and Technical Information of China (English)

    CHEN Sheng-Bing; WEN Ji-Hong; WANG Gang; HAN Xiao-Yun; WEN Xi-Sen

    2011-01-01

    @@ Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams.Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit.Therefore,the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam.However,the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far.In this work,the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment.The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.%Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams. Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit. Therefore, the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam. However, the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far. In this work, the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment. The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.

  9. Reprogramming aging and progeria.

    Science.gov (United States)

    Freije, José M P; López-Otín, Carlos

    2012-12-01

    The aging rate of an organism depends on the ratio of tissue degeneration to tissue repair. As a consequence, molecular alterations that tip this balance toward degeneration cause accelerated aging. Conversely, interventions can be pursued to reduce tissue degeneration or to increase tissue repair with the aim of delaying the onset of age-associated manifestations. Recent studies on the biology of stem cells in aging have revealed the influence of systemic factors on their functionality and demonstrated the feasibility of reprogramming aged and progeroid cells. These results illustrate the reversibility of some aspects of the aging process and encourage the search for new anti-aging and anti-progeria interventions.

  10. Magnetic resonance imaging of the normal placenta.

    Science.gov (United States)

    Blaicher, Wibke; Brugger, Peter C; Mittermayer, Christoph; Schwindt, Jens; Deutinger, Josef; Bernaschek, Gerhard; Prayer, Daniela

    2006-02-01

    The goal of this study was to provide a representative description of the normal placenta with contrast medium-free magnetic resonance imaging (MRI) in order to determine a standard of reference. One hundred consecutive singleton pregnancies were investigated by MRI without application of a contrast medium. The mean gestational age (GA) at the time of investigation was 29.5 weeks (range 19-40). Patients with suspected utero-placental insufficiency (UPI) or placental anomalies were excluded. Signal intensities were assessed and correlated with the respective GA. Antenatal MRI without contrast medium was able to depict placental status and morphological changes during gestation. A regular homogeneous structure was found in weeks 19-23. Subsequently, sporadic, slightly marked lobules appeared, which increased in number and markedness with ongoing gestation. Stratification of the lobules was observed after 36 weeks. The ratio of placental and amniotic fluid signal intensities decreased significantly with higher GA and with placental grading. MRI is well suited as an imaging method for the placenta. Our data may be used as a reference in the assessment of the placenta on MRI, and may have further clinical impact with respect to the determination of UPI.

  11. Magnetic resonance imaging of the normal placenta

    Energy Technology Data Exchange (ETDEWEB)

    Blaicher, Wibke [Department of Gynecology and Obstetrics, University Hospital Vienna (Austria)]. E-mail: wibke.blaicher@meduniwien.ac.at; Brugger, Peter C. [Center of Anatomy and Cell Biology, University Hospital of Vienna (Austria); Mittermayer, Christoph [Department of Pediatrics, Division of Neonatology and Intensive Care, University Hospital of Vienna (Austria); Schwindt, Jens [Department of Pediatrics, Division of Neonatology and Intensive Care, University Hospital of Vienna (Austria); Deutinger, Josef [Department of Gynecology and Obstetrics, University Hospital Vienna (Austria); Bernaschek, Gerhard [Department of Gynecology and Obstetrics, University Hospital Vienna (Austria); Prayer, Daniela [Department of Radiology, Division of Neuroradiology, University Hospital of Vienna (Austria)

    2006-02-15

    The goal of this study was to provide a representative description of the normal placenta with contrast medium-free magnetic resonance imaging (MRI) in order to determine a standard of reference. One hundred consecutive singleton pregnancies were investigated by MRI without application of a contrast medium. The mean gestational age (GA) at the time of investigation was 29.5 weeks (range 19-40). Patients with suspected utero-placental insufficiency (UPI) or placental anomalies were excluded. Signal intensities were assessed and correlated with the respective GA. Antenatal MRI without contrast medium was able to depict placental status and morphological changes during gestation. A regular homogeneous structure was found in weeks 19-23. Subsequently, sporadic, slightly marked lobules appeared, which increased in number and markedness with ongoing gestation. Stratification of the lobules was observed after 36 weeks. The ratio of placental and amniotic fluid signal intensities decreased significantly with higher GA and with placental grading. MRI is well suited as an imaging method for the placenta. Our data may be used as a reference in the assessment of the placenta on MRI, and may have further clinical impact with respect to the determination of UPI.

  12. Sex and Age Effects of Functional Connectivity in Early Adulthood

    NARCIS (Netherlands)

    Zhang, C. (Chao); Cahill, N.D. (Nathan D.); Arbabshirani, M.R. (Mohammad R.); T.J.H. White (Tonya); Baum, S.A. (Stefi A.); Michael, A.M. (Andrew M.)

    2016-01-01

    textabstractFunctional connectivity (FC) in resting-state functional magnetic resonance imaging (rs-fMRI) is widely used to find coactivating regions in the human brain. Despite its widespread use, the effects of sex and age on resting FC are not well characterized, especially during early adulthood

  13. Communication: Direct tests of single-parameter aging

    DEFF Research Database (Denmark)

    Hecksher, Tina; Olsen, Niels Boye; Dyre, Jeppe C.

    2015-01-01

    This paper presents accurate data for the physical aging of organic glasses just below the glass transition probed by monitoring the following quantities after temperature up and down jumps: the shear-mechanical resonance frequency (∼360 kHz), the dielectric loss at 1 Hz, the real part of the die...

  14. Resonant Relaxation near the Massive Black Hole in the Galactic Center

    CERN Document Server

    Hopman, C; Hopman, Clovis; Alexander, Tal

    2006-01-01

    The coherent torques between stars on orbits near massive black holes (MBHs) lead to resonant angular momentum relaxation. Due to the fact that orbits are Keplerian to good approximation, the torques efficiently change the magnitude of the angular momenta and rotate the orbital inclinations. As a result the stars are rapidly randomized. The galactic MBH is a good system for the observational study of resonant relaxation. The age of the young B-stars at a distance of $\\sim0.01 pc$ from the MBH is comparable to the resonant relaxation time, implying that resonant relaxation may have played an important role in their dynamical structure. In contrast, the O-stars in the stellar disks at $\\sim0.1 pc$ are younger than the resonant relaxation time, as required by their dynamical coherence. Resonant relaxation dynamics dominates the event rate of gravitational wave (GW) emission from inspiraling stars into MBHs of masses comparable to the Galactic MBH. Resonant relaxation leads to rates $\\lesssim 10$ times higher tha...

  15. Imaging of the hip joint. Computed tomography versus magnetic resonance imaging

    Science.gov (United States)

    Lang, P.; Genant, H. K.; Jergesen, H. E.; Murray, W. R.

    1992-01-01

    The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.

  16. Resonance locking as the source of rapid tidal migration in the Jupiter and Saturn moon systems

    CERN Document Server

    Fuller, Jim; Quataert, Eliot

    2016-01-01

    The inner moons of Jupiter and Saturn migrate outwards due to tidal energy dissipation within the planets, the details of which remain poorly understood. We demonstrate that resonance locking between moons and internal oscillation modes of the planet can produce rapid tidal migration. Resonance locking arises due to the internal structural evolution of the planet and typically produces an outward migration rate comparable to the age of the solar system. Resonance locking predicts a similar migration timescale but a different effective tidal quality factor Q for each moon. It also predicts nearly constant migration timescales a function of semi-major axis, such that effective Q values were larger in the past. Recent measurements of Jupiter and Saturn's moon systems find effective Q values that are smaller than expected (and are different between moons), and which correspond to migration timescales of roughly 10 Gyr. If confirmed, the measurements are broadly consistent with resonance locking as the dominant so...

  17. High performance Vernier racetrack resonators.

    Science.gov (United States)

    Boeck, Robert; Flueckiger, Jonas; Yun, Han; Chrostowski, Lukas; Jaeger, Nicolas A F

    2012-12-15

    We demonstrate record performance of series-coupled silicon racetrack resonators exhibiting the Vernier effect. Our device has an interstitial peak suppression (IPS) of 25.5 dB, which is 14.5 dB larger than previously reported results. We also demonstrate the relationship between the inter-ring gap distance and the IPS as well as the 3 dB bandwidth (BW) both theoretically and experimentally. Namely, we show that as the inter-ring gap distance increases, the IPS increases and the 3 dB BW decreases.

  18. Evanescent Waves Nuclear Magnetic Resonance.

    Science.gov (United States)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging.

  19. Magnetic resonance tomography in syringomyelia

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, D.; Treisch, J.; Hertel, G.; Schoerner, W.; Fiegler, W.

    1985-12-01

    Thirteen patients with a clinical diagnosis of syringomyelia were examined by nuclear tomography (0.35 T magnet) in the spin-echo mode. In all thirteen patients, the T1 images (Se 400/35) showed a longitudinal cavity with a signal intensity of CSF. The shape and extent of the syrinx could be adequately demonstrated in 12 of the 13 examinations. Downward displacement of the cerebellar tonsils was seen in eight cases. The examination took between half and one hour. Advantages of magnetic resonance tomography (nuclear tomography) include the absence of artifacts, images in the line of the lesion and its non-invasiveness.

  20. Modeling noisy resonant system response

    Science.gov (United States)

    Weber, Patrick Thomas; Walrath, David Edwin

    2017-02-01

    In this paper, a theory-based model replicating empirical acoustic resonant signals is presented and studied to understand sources of noise present in acoustic signals. Statistical properties of empirical signals are quantified and a noise amplitude parameter, which models frequency and amplitude-based noise, is created, defined, and presented. This theory-driven model isolates each phenomenon and allows for parameters to be independently studied. Using seven independent degrees of freedom, this model will accurately reproduce qualitative and quantitative properties measured from laboratory data. Results are presented and demonstrate success in replicating qualitative and quantitative properties of experimental data.

  1. Advances in magnetic resonance 3

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 3, describes a number of important developments which are finding increasing application by chemists. The book contains five chapters and begins with a discussion of how the properties of random molecular rotations reflect themselves in NMR and how they show up, often differently, in other kinds of experiments. This is followed by separate chapters on the Kubo method, showing its equivalence to the Redfield approach in the cases of most general interest; the current state of dynamic nuclear polarization measurements in solutions and what they tell us abou

  2. Hadron scattering, resonances, and QCD

    Energy Technology Data Exchange (ETDEWEB)

    Briceno, Raul [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-12-01

    The non-perturbative nature of quantum chromodynamics (QCD) has historically left a gap in our understanding of the connection between the fundamental theory of the strong interactions and the rich structure of experimentally observed phenomena. For the simplest properties of stable hadrons, this is now circumvented with the use of lattice QCD (LQCD). In this talk I discuss a path towards a rigorous determination of few-hadron observables from LQCD. I illustrate the power of the methodology by presenting recently determined scattering amplitudes in the light-meson sector and their resonance content.

  3. UV, stress and aging

    OpenAIRE

    Debacq-Chainiaux, Florence; Leduc, Cedric; Verbeke, Alix; Toussaint, Olivier

    2014-01-01

    Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic—also called "photo-aging"—resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on ...

  4. PerformAge

    DEFF Research Database (Denmark)

    Fristrup, Tine

    2012-01-01

    a uniformly rosy picture of aging and old age, but unfold an opening up of life taking the heroines and heroes of aging life to the open road in search of themselves and new roles in life as a quest of self-knowledge, self-development – a role for the future. Different viewpoints enabling readers to identify...... closely with the aging self in motion – a life still in becoming as PerformAge....

  5. Age Differences in Brain Activity during Emotion Processing: Reflections of Age-Related Decline or Increased Emotion Regulation?

    OpenAIRE

    2011-01-01

    Despite the fact that physical health and cognitive abilities decline with aging, the ability to regulate emotion remains stable and in some aspects improves across the adult life span. Older adults also show a positivity effect in their attention and memory, with diminished processing of negative stimuli relative to positive stimuli compared with younger adults. The current paper reviews functional magnetic resonance imaging studies investigating age-related differences in emotional processi...

  6. Thalamic structures and associated cognitive functions: Relations with age and aging

    Science.gov (United States)

    Fama, Rosemary; Sullivan, Edith V.

    2015-01-01

    The thalamus, with its cortical, subcortical, and cerebellar connections, is a critical node in networks supporting cognitive functions known to decline in normal aging, including component processes of memory and executive functions of attention and information processing. The macrostructure, microstructure, and neural connectivity of the thalamus changes across the adult lifespan. Structural and functional magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) have demonstrated, regional thalamic volume shrinkage and microstructural degradation, with anterior regions generally more compromised than posterior regions. The integrity of selective thalamic nuclei and projections decline with advancing age, particularly those in thalamofrontal, thalamoparietal, and thalamolimbic networks. This review presents studies that assess the relations between age and aging and the structure, function, and connectivity of the thalamus and associated neural networks and focuses on their relations with processes of attention, speed of information processing, and working and episodic memory. PMID:25862940

  7. Numerical and experimental studies of resonators with reduced resonant frequencies and small electrical sizes

    CERN Document Server

    Hao, T; Edwards, D J; Stevens, C J

    2008-01-01

    Methods on reducing resonant frequencies and electrical sizes of resonators are reported in this paper. Theoreti-cal and numerical analysis has been used and the results for the broadside-coupled resonators from both studies exhibit good agreement. Initial fabrication techniques are proposed and measurement results are compared with simulations. Further high resolution techniques have been envisaged to enhance the performance of the resona-tors. This class of small resonators with low resonant frequencies indicates a variety of applications in the design of microwave devices.

  8. Excitation-energy dependence of the giant dipole resonance width

    Energy Technology Data Exchange (ETDEWEB)

    Enders, G.; Berg, F.D.; Hagel, K.; Kuehn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O. (II. Physikalisches Institut, Universitaet, Giessen, Giessen (Germany)); Charity, R.J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K.D.; Holzmann, R.; Mayer, R.S.; Simon, R.S.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung Darmstadt, Darmstadt (Germany)); Casini, G.; Olmi, A.; Stefanini, A.A. (Istituto Nazionale di Fisica Nucleare and University of Florence, Florence (Italy))

    1992-07-13

    High-energy {gamma} rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of {sup 136}Xe+{sup 48}Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width {Gamma} is studied as a function of the fragment excitation energy {ital E}{sup *}. A saturation at about {Gamma}=10 MeV is observed for {ital E}{sup *}/{ital A}{ge}1.0 MeV/nucleon.

  9. [Resonant characteristics of the external acoustic meatus in the children undergoing electroacoustical correction of hearing].

    Science.gov (United States)

    Savel'eva, E E

    2012-01-01

    The objective of this study was to estimate the factors influencing the efficacy and quality of electroacoustical correction of hearing in the children and elucidate specific resonant characteristics of the external acoustic meatus in the patients at the age varying from 6 months to 5 years. The hearing acuity was estimated in 87 children aged from 5 months to 5 years presenting with censorineural impairment of hearing or deafness with the use of psychoacoustic and electrophysiological techniques. Special attention was given to the assessment of resonant characteristics of the external acoustic canal. The resonant characteristics of the external acoustic canal in the children differ from those in adult subjects. This fact should be taken into consideration in planning the electroacoustical correction of hearing in the children.

  10. Dynamical generation of hadronic resonances

    CERN Document Server

    Wolkanowski, Thomas

    2014-01-01

    One type of dynamical generation consists in the formation of multiple hadronic resonances from single seed states by incorporating hadronic loop contributions on the level of $s$-wave propagators. Along this line, we study the propagator poles within two models of scalar resonances and report on the status of our work: (i) Using a simple quantum field theory describing the decay of $f_{0}(500)$ into two pions, we may obtain a second, additional pole on the first Riemann sheet below the pion-pion threshold (i.e., a stable state can emerge). (ii) We perform a numerical study of the pole(s) of $a_{0}(1450)$ by using as an input the results obtained in the extended Linear Sigma Model (eLSM). Here, we do not find any additional pole besides the original one, thus we cannot obtain $a_{0}(980)$ as an emerging state. (iii) We finally demonstrate that, although the coupling constants in typical effective models might be large, the next-to-leading-order contribution to the decay amplitude is usually small and can be n...

  11. Spin-orbit ferromagnetic resonance

    Science.gov (United States)

    Ferguson, Andrew

    2013-03-01

    In conventional magnetic resonance techniques the magnitude and direction of the oscillatory magnetic field are (at least approximately) known. This oscillatory field is used to probe the properties of a spin ensemble. Here, I will describe experiments that do the inverse. I will discuss how we use a magnetic resonance technique to map out the current-induced effective magnetic fields in the ferromagnetic semiconductors (Ga,Mn)As and (Ga,Mn)(As,P). These current-induced fields have their origin in the spin-orbit interaction. Effective magnetic fields are observed with symmetries which resemble the Dresselhaus and Rashba spin-orbit interactions and which depend on the diagonal and off-diagonal strain respectively. Ferromagnetic semiconductor materials of different strains, annealing conditions and concentrations are studied and the results compared with theoretical calculations. Our original study measured the rectification voltage coming from the product of the oscillatory magnetoresistance, during magnetisation precession, and the alternating current. More recently we have developed an impedance matching technique which enables us to extract microwave voltages from these high resistance (10 k Ω) samples. In this way we measure the microwave voltage coming from the product of the oscillating magneto-resistance and a direct current. The direct current is observed to affect the magnetisation precession, indicating that anti-damping as well as field-like torques can originate from the spin-orbit interaction.

  12. Threshold enhancement of diphoton resonances

    Science.gov (United States)

    Bharucha, Aoife; Djouadi, Abdelhak; Goudelis, Andreas

    2016-10-01

    We revisit a mechanism to enhance the decay width of (pseudo-)scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. Motivated by the recent LHC data, indicating the presence of an excess in the diphoton spectrum at approximately 750 GeV, we illustrate this threshold enhancement mechanism in the case of a 750 GeV pseudoscalar boson A with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 1/2MA threshold and a small decay width, photons predominantly through loops of charginos with masses close to 1/2MA and ii) a two Higgs doublet model in which A is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. In both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the A resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

  13. Resonant spectra of quadrupolar anions

    Science.gov (United States)

    Fossez, K.; Mao, Xingze; Nazarewicz, W.; Michel, N.; Garrett, W. R.; Płoszajczak, M.

    2016-09-01

    In quadrupole-bound anions, an extra electron is attached at a sufficiently large quadrupole moment of a neutral molecule, which is lacking a permanent dipole moment. The nature of the bound states and low-lying resonances of such anions is of interest for understanding the threshold behavior of open quantum systems in general. In this work, we investigate the properties of quadrupolar anions as halo systems, the formation of rotational bands, and the transition from a subcritical to supercritical electric quadrupole moment. We solve the electron-plus-rotor problem using a nonadiabatic coupled-channel formalism by employing the Berggren ensemble, which explicitly contains bound states, narrow resonances, and the scattering continuum. The rotor is treated as a linear triad of point charges with zero monopole and dipole moments and nonzero quadrupole moment. We demonstrate that binding energies and radii of quadrupolar anions strictly follow the scaling laws for two-body halo systems. Contrary to the case of dipolar anions, ground-state band of quadrupolar anions smoothly extend into the continuum, and many rotational bands could be identified above the detachment threshold. We study the evolution of a bound state of an anion as it dives into the continuum at a critical quadrupole moment and we show that the associated critical exponent is α =2 . Everything considered, quadrupolar anions represent a perfect laboratory for the studies of marginally bound open quantum systems.

  14. Threshold enhancement of diphoton resonances

    Directory of Open Access Journals (Sweden)

    Aoife Bharucha

    2016-10-01

    Full Text Available We revisit a mechanism to enhance the decay width of (pseudo-scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. Motivated by the recent LHC data, indicating the presence of an excess in the diphoton spectrum at approximately 750 GeV, we illustrate this threshold enhancement mechanism in the case of a 750 GeV pseudoscalar boson A with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 12MA threshold and a small decay width, <1 MeV. The implications of such a threshold enhancement are discussed in two explicit scenarios: i the Minimal Supersymmetric Standard Model in which the A state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through loops of charginos with masses close to 12MA and ii a two Higgs doublet model in which A is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. In both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the A resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

  15. Single-molecule stochastic resonance

    CERN Document Server

    Hayashi, K; Manosas, M; Huguet, J M; Ritort, F; 10.1103/PhysRevX.2.031012

    2012-01-01

    Stochastic resonance (SR) is a well known phenomenon in dynamical systems. It consists of the amplification and optimization of the response of a system assisted by stochastic noise. Here we carry out the first experimental study of SR in single DNA hairpins which exhibit cooperatively folding/unfolding transitions under the action of an applied oscillating mechanical force with optical tweezers. By varying the frequency of the force oscillation, we investigated the folding/unfolding kinetics of DNA hairpins in a periodically driven bistable free-energy potential. We measured several SR quantifiers under varied conditions of the experimental setup such as trap stiffness and length of the molecular handles used for single-molecule manipulation. We find that the signal-to-noise ratio (SNR) of the spectral density of measured fluctuations in molecular extension of the DNA hairpins is a good quantifier of the SR. The frequency dependence of the SNR exhibits a peak at a frequency value given by the resonance match...

  16. Spectrally resolved resonant propulsion of dielectric microspheres

    CERN Document Server

    Li, Yangcheng; Limberopoulos, Nicholaos I; Urbas, Augustine M; Astratov, Vasily N

    2015-01-01

    Use of resonant light forces opens up a unique approach to high-volume sorting of microspherical resonators with much higher uniformity of resonances compared to that in coupled-cavity structures obtained by the best semiconductor technologies. In this work, the spectral response of the propulsion forces exerted on polystyrene microspheres near tapered microfibers is directly observed. The measurements are based on the control of the detuning between the tunable laser and internal resonances in each sphere with accuracy higher than the width of the resonances. The measured spectral shape of the propulsion forces correlates well with the whispering-gallery mode resonances in the microspheres. The existence of a stable radial trap for the microspheres propelled along the taper is demonstrated. The giant force peaks observed for 20-{\\mu}m spheres are found to be in a good agreement with a model calculation demonstrating an efficient use of the light momentum for propelling the microspheres.

  17. Developing accelerometer based on graphene nanoribbon resonators

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jeong Won, E-mail: jwkang@ut.ac.kr [Department of Computer Engineering, Korea National University of Transportation, Chungju 380-702 (Korea, Republic of); Lee, Jun Ha, E-mail: junha@smu.ac.kr [Department of Computer System Engineering, Sangmyung University, Chonan 330-720 (Korea, Republic of); Hwang, Ho Jung, E-mail: hjhwang@cau.ac.kr [School of Electrical and Electronic Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Kim, Ki-Sub, E-mail: kks1114@ut.ac.kr [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-702 (Korea, Republic of)

    2012-10-01

    We investigated an ultrahigh sensitive accelerometer based on graphene nanoribbon resonators. Sensing acceleration can be made by their resonance frequency shift and/or their capacitance change. Schematics and the static properties were introduced and the dynamic properties were investigated via classical molecular dynamics simulation. As the acceleration increased, the oscillations of the deflections were going dramatically faster and the mean deflections increased, then the capacitance continually varied with large amplitudes and the resonance frequencies linearly increased in a log–log scale by power regression. The energy loss decreased with increasing time, and the average quality factors were dramatically reduced with increasing acceleration. -- Highlights: ► Ultrahigh sensitive accelerometer based on graphene nanoribbon resonators. ► Sensing acceleration by resonance frequency shift and/or capacitance change. ► Resonance frequencies linearly increased with increasing acceleration in a log–log scale. ► Quality factors were dramatically reduced with increasing acceleration.

  18. Bimaterial Thermal Compensators for WGM Resonators

    Science.gov (United States)

    Savchenkov, Anatoliy; Yu, Nan; Maleki, Lute; Iltchenko, Vladimir; Strekalov, Dmitry

    2008-01-01

    Bimaterial thermal compensators have been proposed as inexpensive means of preventing (to first order) or reducing temperature-related changes in the resonance frequencies of whispering-gallery-mode (WGM) optical resonators. A bimaterial compensator would apply, to a WGM resonator, a pressure that would slightly change the shape of the resonator and thereby change its resonance frequencies. Through suitable choice of the compensator dimensions and materials, it should be possible to make the temperature dependence of the pressure-induced frequency shift equal in magnitude and opposite in sign to the temperature dependence of the frequency shift of the uncompensated resonator so that, to first order, a change in temperature would cause zero net change in frequency.

  19. Surface acoustic wave mode conversion resonator

    Science.gov (United States)

    Martin, S. J.; Gunshor, R. L.; Melloch, M. R.; Datta, S.; Pierret, R. F.

    1983-08-01

    The fact that a ZnO-on-Si structure supports two distinct surface waves, referred to as the Rayleigh and the Sezawa modes, if the ZnO layer is sufficiently thick is recalled. A description is given of a unique surface wave resonator that operates by efficiently converting between the two modes at the resonant frequency. Since input and output coupling is effected through different modes, the mode conversion resonator promises enhanced out-of-band signal rejection. A Rayleigh wave traversing the resonant cavity in one direction is reflected as a Sezawa wave. It is pointed out that the off-resonance rejection of the mode conversion resonator could be enhanced by designing the transducers to minimize the level of cross coupling between transducers and propagating modes.

  20. Fano resonances from gradient-index metamaterials.

    Science.gov (United States)

    Xu, Yadong; Li, Sucheng; Hou, Bo; Chen, Huanyang

    2016-01-27

    Fano resonances - resonant scattering features with a characteristic asymmetric profile - have generated much interest, due to their extensive and valuable applications in chemical or biological sensors, new types of optical switches, lasers and nonlinear optics. They have been observed in a wide variety of resonant optical systems, including photonic crystals, metamaterials, metallic gratings and nanostructures. In this work, a waveguide structure is designed by employing gradient-index metamaterials, supporting strong Fano resonances with extremely sharp spectra. As the changes in the transmission spectrum originate from the interaction of guided modes from different channels, instead of resonance structures or metamolecules, the Fano resonances can be observed for both transverse electric and transverse magnetic polarizations. These findings are verified by fine agreement with analytical calculations and experimental results at microwave, as well as simulated results at near infrared frequencies.

  1. Secular resonances with Ceres and Vesta

    CERN Document Server

    Tsirvoulis, Georgios

    2016-01-01

    In this work we explore dynamical perturbations induced by the massive asteroids Ceres and Vesta on main-belt asteroids through secular resonances. First we determine the location of the linear secular resonances with Ceres and Vesta in the main belt, using a purely numerical technique. Then we use a set of numerical simulations of fictitious asteroids to investigate the importance of these secular resonances in the orbital evolution of main-belt asteroids. We found, evaluating the magnitude of the perturbations in the proper elements of the test particles, that in some cases the strength of these secular resonances is comparable to that of known non-linear secular resonances with the giant planets. Finally we explore the asteroid families that are crossed by the secular resonances we studied, and identified several cases where the latter seem to play an important role in their post-impact evolution.

  2. Age determination of raccoons

    Science.gov (United States)

    Grau, G.A.; Sanderson, G.C.; Rogers, J.P.

    1970-01-01

    Age criteria, based on 61 skulls and eye lenses from 103 known-age captives, are described for separating raccoons (Procyon lotor) into eight age-classes as follows: young-of-the-year, 1, 2, 3, 4, 5, 6-7, > 7 years. Criteria studied were eye lens nitrogen, cranial suture closure, tooth wear and incisor cementum layers. Lens nitrogen increased rapidly up to 12 months of age, but at much reduced rate thereafter. Total lens nitrogen was useful only in separating young-of-the-year from adults. The closure sequence for five cranial sutures accurately divided the total known-age sample of males into seven groups, and the adults into five groups. The tooth wear criteria divided the known-age sample into five relative age groups, but aging of individuals by this method was inaccurate. Histological sectioning of known-age teeth was the best method of observing layering in the cementum tissue. The technique of basing estimation of age on cementum ring counts, although subjective, was accurate for aging individuals through their fourth year but tended to underestimate the age of animals over 4 years old. However, suture closure or tooth wear can be used to identify males over 4 years old. In field studies, technical difficulties limit the utility of age estimation by cementum layers. Maximum root thickness of the lower canine was accurate in determining the sex of individuals from 5 months to ,at least 48 months of age.

  3. Torque-mixing Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan; Diao, Zhu; Belov, Miro; Burgess, Jacob; Compton, Shawn; Hiebert, Wayne; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory; Thomson, Douglas; Freeman, Mark

    A universal, mechanical torque method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by induction, a signal proportional to the transverse component of a precessing dipole moment can be measured as a pure mechanical torque in broadband, frequency-swept spectroscopy. Comprehensive electron spin resonance of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature are presented to demonstrate the method. The rich detail allows analysis of even complex 3D spin textures.

  4. Humanitarian mine detection by acoustic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Kercel, S.W.

    1998-03-01

    The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical

  5. Resonance ionization scheme development for europium

    CERN Document Server

    Chrysalidis, K; Fedosseev, V N; Marsh, B A; Naubereit, P; Rothe, S; Seiffert, C; Kron, T; Wendt, K

    2017-01-01

    Odd-parity autoionizing states of europium have been investigated by resonance ionization spectroscopy via two-step, two-resonance excitations. The aim of this work was to establish ionization schemes specifically suited for europium ion beam production using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). 13 new RILIS-compatible ionization schemes are proposed. The scheme development was the first application of the Photo Ionization Spectroscopy Apparatus (PISA) which has recently been integrated into the RILIS setup.

  6. Pressure effects in multiple resonant multiphoton transitions

    Science.gov (United States)

    Maïnos, C.; Le Duff, Y.; Castex, M. C.; Boursey, E.

    1989-02-01

    Although the rotational structure of a multiphoton process generally remains unaltered over a large range of gas pressure, this is not the case when multiple resonances are present. The rotational structure observed through intermediate rotational levels in a multiphoton process depends strongly on the resonance conditions. We show, for the NO molecule, that this structure changes drastically when the resonance conditions are modified by intermolecular collisions.

  7. Monostable array-enhanced stochastic resonance.

    Science.gov (United States)

    Lindner, J F; Breen, B J; Wills, M E; Bulsara, A R; Ditto, W L

    2001-05-01

    We present a simple nonlinear system that exhibits multiple distinct stochastic resonances. By adjusting the noise and coupling of an array of underdamped, monostable oscillators, we modify the array's natural frequencies so that the spectral response of a typical oscillator in an array of N oscillators exhibits N-1 different stochastic resonances. Such families of resonances may elucidate and facilitate a variety of noise-mediated cooperative phenomena, such as noise-enhanced propagation, in a broad class of similar nonlinear systems.

  8. Emittance growths in resonance crossing at FFAGs

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.Y.; /Fermilab; Pang, X.; Wang, F.; Wang, X.; Lee, S.Y.; /Indiana U.

    2007-10-01

    Scaling laws of the emittance growth for a beam crossing the 6th-order systematic space-charge resonances and the random-octupole driven 4th-order resonance are obtained by numerical multi-particle simulations. These laws can be important in setting the minimum acceleration rate and maximum tolerable resonance strength for the design of non-scaling fixed-field alternating gradient accelerators.

  9. CMOS-compatible athermal silicon microring resonators.

    Science.gov (United States)

    Guha, Biswajeet; Kyotoku, Bernardo B C; Lipson, Michal

    2010-02-15

    We propose a new class of resonant silicon optical devices, consisting of a ring resonator coupled to a Mach-Zehnder interferometer, which is passively temperature compensated by tailoring the optical mode confinement in the waveguides. We demonstrate operation of the device over a wide temperature range of 80 degrees. The fundamental principle behind this work can be extended to other photonic devices based on resonators such as modulators, routers, switches and filters.

  10. Tunable coplanar waveguide resonator with nanowires

    Institute of Scientific and Technical Information of China (English)

    周渝; 郏涛; 翟计全; 汪橙; 钟先茜; 曹志敏; 孙国柱; 康琳; 吴培亨

    2015-01-01

    A tunable superconducting half-wavelength coplanar waveguide resonator (CPWR) with Nb parallel nanowires ∼300 nm in width embedded in the center conductor was designed, fabricated, and measured. The frequency shift and the amplitude attenuation of the resonance peak under irradiation of 404-nm pulse laser were observed with different light powers at 4.2 K. The RF power supplied to such a CPWR can serve as current bias, which will affect the light response of the resonator.

  11. Study of Mode Coupling on Coaxial Resonators

    Institute of Scientific and Technical Information of China (English)

    Rui Liu; Hong-Fu Li

    2011-01-01

    A study of mode coupling phenomenon of coaxial resonators has been conducted with theories.Through establishing the source-free transmission line equation,boundary conditions of the coaxial resonators with a corrugated inner conductor are analyzed.In the end,calculations are performed in a wide range of corrugation parameters for the resonator of the Karisruhe Institute of Technology (KIT) relevant coaxial gyrotron.

  12. Polarization effects in recoil-induced resonances

    Science.gov (United States)

    Lazebnyi, D. B.; Brazhnikov, D. V.; Taichenachev, A. V.; Yudin, V. I.

    2017-01-01

    The effect of the field polarization on the amplitude of recoil-induced resonances (RIRs) is considered for laser-cooled free atoms and for atoms in a working magneto-optical trap (MOT). For all closed dipole transitions, explicit analytical expressions are obtained for the polarization dependence of the resonance amplitudes within a perturbation theory. Optimal polarization conditions are found for the observation of resonances.

  13. Effective resonant interactions via a driving field

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, A B [Departamento de FIsica, Universidad de Guadalajara, Revolucion 1500, Guadalajara 44420 (Mexico); Sainz, I [Departamento de FIsica, Universidad de Guadalajara, Revolucion 1500, Guadalajara 44420 (Mexico); Saavedra, C [Center for Quantum Optics and Quantum Information, Departamento de FIsica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)

    2004-11-01

    Effective resonant quantum atom-field interactions are studied. These resonant interactions are induced by the presence of an external classical driving field. An adequate choice for frequencies of the driving field produces nonlinear effective Hamiltonians both for atom-field and for spin-spin interactions. It is shown that the exact numerical evolution for each resonance condition is well described by the corresponding effective Hamiltonian.

  14. Acoustic resonance frequency locked photoacoustic spectrometer

    Science.gov (United States)

    Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

    2003-09-09

    A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell, the acoustic source having a source frequency; repeatedly and continuously sweeping the source frequency across the resonance frequency at a sweep rate; and employing an odd-harmonic of the source frequency sweep rate to maintain the source frequency sweep centered on the resonance frequency.

  15. Functional Magnetic Resonance Imaging of Cognitive Processing in Young Adults with Down Syndrome

    Science.gov (United States)

    Jacola, Lisa M.; Byars, Anna W.; Chalfonte-Evans, Melinda; Schmithorst, Vincent J.; Hickey, Fran; Patterson, Bonnie; Hotze, Stephanie; Vannest, Jennifer; Chiu, Chung-Yiu; Holland, Scott K.; Schapiro, Mark B.

    2011-01-01

    The authors used functional magnetic resonance imaging (fMRI) to investigate neural activation during a semantic-classification/object-recognition task in 13 persons with Down syndrome and 12 typically developing control participants (age range = 12-26 years). A comparison between groups suggested atypical patterns of brain activation for the…

  16. Functional Magnetic Resonance Imaging Studies of Inhibition and Attention in ADHD

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2013-03-01

    Full Text Available Researchers at King's College, London; Kyushu University, Japan; and Barcelona, Spain conducted a meta-analysis of functional magnetic resonance imaging (fMRI in ADHD during inhibition and attention tasks, with reference to age and effects of long-term use of stimulant medication.

  17. Figural memory performance and functional magnetic resonance imaging activity across the adult lifespan.

    Science.gov (United States)

    Jamadar, Sharna; Assaf, Michal; Jagannathan, Kanchana; Anderson, Karen; Pearlson, Godfrey D

    2013-01-01

    We examined performance and functional magnetic resonance imaging activity in participants (n = 235) aged 17-81 years on a nonverbal recognition memory task, figural memory. Reaction time, error rate, and response bias measures indicated that the youngest and oldest participants were faster, made fewer errors, and showed a more conservative response bias than participants in the median age ranges. Encoding and Recognition phases activated a distributed bilateral network encompassing prefrontal, subcortical, lateral, and medial temporal and occipital regions. Activation during Encoding phase did not correlate with age. During Recognition, task-related activation for correctly identified targets (Hit-Targets) correlated linearly positively with age; nontask related activity correlated negative quadratically with age. During correctly identified distractors (Hit-Distractors) activity in task-related regions correlated positive linearly with age, nontask activity showed positive and negative quadratic relationships with age. Missed-Targets activity did not correlate with age. We concluded that figural memory performance and functional magnetic resonance imaging activity during Recognition but not Encoding was affected both by continued maturation of the brain in the early 20s and compensatory recruitment of additional brain regions during recognition memory in old age.

  18. Micro string resonators as temperature sensors

    DEFF Research Database (Denmark)

    Larsen, T.; Schmid, S.; Boisen, A.

    2013-01-01

    The resonance frequency of strings is highly sensitive to temperature. In this work we have investigated the applicability of micro string resonators as temperature sensors. The resonance frequency of strings is a function of the tensile stress which is coupled to temperature by the thermal...... expansion of the string and the frame clamping it. The sensitivity improves when the length and pre-stress are reduced and the difference in thermal expansion, Young's modulus and resonant mode are increased. At low tensile stress, the sensitivity becomes highly dependent on temperature. The investigation...

  19. The resonance phenomena and state of health

    Directory of Open Access Journals (Sweden)

    Sikura A.Y.

    2010-06-01

    Full Text Available The question of dependence of the state of health is examined from the resonance phenomena in the liquid environments of organism, roles herein physical loadings. It is rotined that resonance waves can compensate structural violations on a tissue, system levels. The oppressive operating is the same compensated on the organism of man. The physical loading in a complex with other external resonance phenomena causes substantial resonance vibrations in all systems of organism. It is necessary to take into account it on employments on physical education and to use all necessary rehabilitation facilities.

  20. Magnetic resonance imaging of hemochromatosis arthropathy

    Energy Technology Data Exchange (ETDEWEB)

    Eustace, S. [Dept. of Radiology, Deaconess Hospital and Harvard Medical School, Boston, MA (United States); Buff, B. [Dept. of Radiology, Deaconess Hospital and Harvard Medical School, Boston, MA (United States); McCarthy, C. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland); MacMathuana, P. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland); Gilligan, P. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland); Ennis, J.T. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland)

    1994-10-01

    This study was undertaken to compare plain film radiography and magnetic resonance imaging in the assessment of hemochromatosis arthropathy of the knees of ten patients with a biopsy-proven diagnosis. Both modalities enabled visualisation of bony degenerative changes; magnetic resonance imaging enabled additional visualization of deformity of both cartilage and menisci. Magnetic resonance imaging failed reliably to confirm the presence of intra-articular iron in the patients studied. No correlation was observed between synovial fluid magnetic resonance signal values, corresponding serum ferritin levels, or the severity of the observed degenerative changes. (orig.)

  1. Polarimetric Properties of Optically Resonant Nanostructures

    Science.gov (United States)

    Theisen, Michael John

    Optically resonant nanostructures have been incorporated into a variety of devices used in a number of different fields. In this thesis, we explore optically resonant nanostructures in two forms. First we investigate a relatively new material, gallium implanted silicon (Si:Ga). We cover the fabrication process and experimentally find the optical properties as a function of both dose and wavelength. We then use the properties of this new material to create suspended arrays of Si:Ga nanowires, and determine their optical characteristics. In the second part of this thesis, we use more conventional materials and fabrication procedures to investigate the phase effects of guided mode resonators. We look at the spectral phase effects for a grating coupled silicon-on-insulator based guided mode resonator. We also look the angular phase effects of a surface plasmon polariton based guided mode resonator, comparing experimental results to theory calculated with rigorous coupled wave analysis for both cases. In addition, the guided mode resonance is modeled as a Fano resonance to gain insight into the functional form of the phase. Knowing the phase response of guided mode resonances may allow the creation of guided mode resonance based devices with higher sensitivity than traditional reflectance based devices.

  2. Demographics of Resonances in Exoplanetary Systems

    Science.gov (United States)

    Ragozzine, Darin; Conaway, James L.; MacDonald, Mariah G.; Sallee, Victor

    2016-10-01

    NASA's Kepler Space Telescope has identified ~700 systems of multiple transiting exoplanets containing ~1700 planets. Most of these multi-transiting systems have 3-5 planets small planets with periods of roughly 5-50 days and are known as Systems with Tightly-spaced Inner Planets (STIPs). These information-rich exoplanetary systems have precisely measured period ratios which allows for the identification and characterization of orbital mean motion resonances. Improved understanding of the resonant populations will reveal much about the formation and evolution of planetary systems. Lissauer, Ragozzine, et al. 2011 found that most Kepler systems were not in resonance, but that there was a small excess of planets wide of resonance. We present new analyses that rigorously identify the frequency of planets in multiple resonances (including three-body resonances) and thus identify many specific new results on the demographics of resonances. We also show that the apparent over-abundance of resonances can be attributed to a difference in inclinations (potentially from dissipation) with implications for the true underlying frequency of resonant systems. We compare the period ratio distribution of Kepler (corrected for inclination biases) to Radial Velocity (RV) surveys and conclude that RV systems are often missing small intermediate planets. This has serious implications for the completeness of RV identification of planets in STIPs.

  3. Q-enhanced racetrack micro-resonators

    CERN Document Server

    Chamorro-Posada, Pedro

    2016-01-01

    A Q enhancement strategy for racetrack micro -resonators is put forward. The design is based on the modification of the resonator geometry in order to mitigate the two main sources of radiation loss in the presence of curved waveguides: the couplings from the straight waveguides to the bent sections and the continuous loss at the curved waveguide sectors. Numerical calculations show over $100\\%$ improvement of the Q factor in silicon nitride resonators. At the same time, the modifications of the geometry do not affect the coupling properties of the resonators in integrated optical circuits.

  4. RESONANCE RADIATION OF SUBMERGED INFINITE CYLINDRICAL SHELL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The resonance sound radiation from submerged infinite elastic cylindrical shell, excited by internal harmonic line force, is investigated. The shell radiation power is presented in terms of resonant modal radiation derived from resonance radiation theory (RRT). The resonance radiation formulae are derived from classical Rayleigh normal mode solution, which are useful for understanding the mechanism of sound radiation from submerged shells. As an example, numerical calculation of a thin steel cylindrical shell is done by using these two methods. It seems that the results of RRT solutions are in good agreement with that of Rayleigh normal mode solutions.

  5. Quantum communication between remote mechanical resonators

    Science.gov (United States)

    Felicetti, S.; Fedortchenko, S.; Rossi, R.; Ducci, S.; Favero, I.; Coudreau, T.; Milman, P.

    2017-02-01

    Mechanical resonators represent one of the most promising candidates to mediate the interaction between different quantum technologies, bridging the gap between efficient quantum computation and long-distance quantum communication. Here, we introduce an interferometric scheme where the interaction of a mechanical resonator with input-output quantum pulses is controlled by an independent classical drive. We design protocols for state teleportation and direct quantum state transfer, between distant mechanical resonators. The proposed device, feasible with state-of-the-art technology, can serve as a building block for the implementation of long-distance quantum networks of mechanical resonators.

  6. Feshbach Resonances in Kerr Frequency Combs

    CERN Document Server

    Matsko, Andrey B

    2014-01-01

    We show that both the power and repetition rate of a frequency comb generated in a nonlinear ring resonator, pumped with continuous wave (cw) coherent light, are modulated. The modulation is brought about by the interaction of the cw background with optical pulses excited in the resonator, and occurs in resonators with nonzero high-order chromatic dispersion and wavelength-dependent quality factor. The modulation frequency corresponds to the detuning of the pump frequency from the eigenfrequency of the pumped mode in the resonator.

  7. Composite spin-1 resonances at the LHC

    CERN Document Server

    Low, Matthew; Wang, Lian-Tao

    2015-01-01

    In this paper, we discuss the signal of composite spin-1 resonances at the LHC. Motivated by the possible observation of a diboson resonance in the 8 TeV LHC data, we demonstrate that vector resonances from composite Higgs models are able to describe the data. We pay particular attention to the role played by fermion partial compositeness, which is a common feature in composite Higgs models. The parameter space that is both able to account for the diboson excess and passes electroweak precision and flavor tests is explored. Finally, we make projections for signals of such resonances at the 13 TeV run of the LHC.

  8. Few-body resonances in light nuclei

    CERN Document Server

    Csoto, A

    2000-01-01

    We have localized several few-body resonances in light nuclei, using methods which can properly handle two- or three-body resonant states. Among other results, we predict the existence of a three-neutron resonance, small spin-orbit splittings between the low-lying states in He-5 and Li-5, the nonexistence of the soft dipole resonance in He-6, new 1+ states in Li-8 and B-8, and the presence of a nonlinear amplification phenomenon in the 0+_2 state of C-12.

  9. Scalar-Pseudoscalar scattering and pseudoscalar resonances

    CERN Document Server

    Albaladejo, M

    2010-01-01

    The interactions between the f_0(980) and a_0(980) scalar resonances and the lightest pseudoscalar mesons are studied. We first obtain the interacting kernels, without including any ad hoc free parameter, because the lightest scalar resonances are dynamically generated. These kernels are unitarized, giving the final amplitudes, which generate pseudoscalar resonances, associated with the K(1460), \\pi(1300), \\pi(1800), \\eta(1475) and X(1835). We also consider the exotic channels with I=3/2 and I^G=1^+ quantum numbers. The former could be also resonant in agreement with a previous prediction.

  10. Measurement of global and local resonance terms

    CERN Document Server

    Tomás, R; Calaga, R; Fischer, W; Franchi, A; Rumolo, Giovanni

    2005-01-01

    Recently, resonance driving terms were successfully measured in the CERN SPS and the BNL RHIC from the Fourier spectrum of beam position monitor (BPM) data. Based on these measurements a new analysis has been derived to extract truly local observables from BPM data. These local observables are called local resonance terms since they share some similarities with the global resonance terms. In this paper we derive these local terms analytically and present experimental measurements of sextupolar global and local resonance terms in RHIC. Nondestructive measurements of these terms using ac dipoles are also presented.

  11. Magnetic resonance imaging in primates. The example of the mouse lemur (Microcebus murinus: From detection of pathological aging to therapeutic evaluations Imagerie par résonance magnétique chez les primates. L’exemple du microcèbe murin (Microcebus murinus : De la détection du vieillissement cérébral pathologique à l'évaluation thérapeutique

    Directory of Open Access Journals (Sweden)

    Nadine El Tannir El Tayara

    2011-02-01

    Full Text Available Cerebral aging is a major public health issue in our societies as the aged population increases dramatically. It leads in many cases to neurodegenerative diseases such as Alzheimer disease (AD. Rodents and particularly transgenic mice are widely used as models for research on physiopathology of cerebral aging, neurodegenerative diseases and for the evaluation of therapies. However these models do not mimic all the pathophysiological aspects of human diseases. Complementary models such as non-human primates are phylogenetically close to humans and thus more predictive of drug efficiency in humans. Mouse lemur (Microcebus murinus is a small primate (about 12cm, 100g described as a useful model of cerebral aging and as a potential model of AD. Indeed several animals develop age-associated cerebral alterations like amyloidosis and other cerebral changes. Non invasive medical imaging methods such as magnetic resonance imaging (MRI can be used to follow-up brain changes in these animals. In this review, we present how mouse lemurs can be followed-up by MRI and how MRI can be used during therapeutic evaluations and other applications in this model. MR images can be used to follow-up cerebral anatomy in mouse lemurs. It allows for the description of age-associated atrophic processes, age-associated iron accumulation, and vascular anatomy (thanks to MR angiography. Cerebral glucose uptake can be studied in mouse lemurs with other in vivo imaging modalities such as positron emission tomography (PET. In this case, MRI can be used as a support for quantification of radioligand uptake in specific structures. Ex vivo MR imaging is another MR protocol that can be used to describe cerebral aging in lemurs. It provides high resolution 3D histological brain images and allows for studying exquisite anatomical details or microhemorrhages. Finally, MRI can be used to practice cerebral surgery in lemurs and determine coordinates for stereotactic injections. It can

  12. Resonance Raman Optical Activity and Surface Enhanced Resonance Raman Optical Activity analysis of Cytochrome C

    DEFF Research Database (Denmark)

    Johannessen, Christian; Abdali, Salim; White, Peter C.

    2007-01-01

    to resonance enhanced skeletal porphyrin vibrations, more pronounced than any contribution from the protein back-bone. Combining the intrinsic resonance enhancement of cytochrome c with surface plasmon enhancement by colloidal silver particles, the Surface Enhanced Resonance Raman Scattering (SERRS) and Chiral......, while some disparities were observed between the resonance ROA and ChERS spectra. The difference can be ascribed perturbations of the physical properties of the protein upon adhesion to the surface of the silver colloids....

  13. NIA Aging Cell Repository

    Data.gov (United States)

    Federal Laboratory Consortium — To facilitate aging research on cells in culture, the NIA provides support for the NIA Aging Cell Repository, located at the Coriell Institute for Medical Research...

  14. Alaska Radiometric Ages

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Alaska Radiometric Age file is a database of radiometric ages of rocks or minerals sampled from Alaska. The data was collected from professional publications...

  15. Visual Signs of Ageing

    Directory of Open Access Journals (Sweden)

    Helle Rexbye

    2007-07-01

    Full Text Available Consumer culture has placed the ageing body in a dilemma of representation. Physical appearance has become increasingly important as a symbol of identity, and at the same time society idealizes youth. This study explores visual ageing empirically. By using photographs of older persons (70+ as starting point, it is explored how visual age is assessed and interpreted. It is shown that informants read age in a spread of stages and categories. Main age indicators are biological markers: skin, eyes, and hair colour, but supplemented by vigour, style, and grooming. Furthermore, in-depth interviews indicate that visual age is mainly interpreted into categories and moral regulations rooted in early modernity. Subsequently the question of a postmodern perspective of visual ageing is discussed in this article. The empirical findings in the study question a postmodern fluidity of visual signs – at least when the concern is signs of ageing.

  16. [Aging and gynecologic cancer].

    Science.gov (United States)

    Arrighi, Arturo A

    2005-01-01

    The interrelation between cancer and ageing in women is emphasized, on its increased incidence, in their molecular background, into the particular biological characteristics of the different tumors and the effects of ageing in the affected women.

  17. Memory and Aging

    Science.gov (United States)

    Memory and Aging Losing keys, misplacing a wallet, or forgetting someone’s name are common experiences. But for people nearing or over age 65, such memory lapses can be frightening. They wonder if they ...

  18. Aging and Health: Cataracts

    Science.gov (United States)

    ... Problems Glaucoma Macular Degeneration Join our e-newsletter! Aging & Health A to Z Cataracts Basic Facts & Information ... Are Cataracts? Cataracts are a common result of aging and occur frequently in older people. About one ...

  19. Aging changes in immunity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004008.htm Aging changes in immunity To use the sharing features ... cells and antibodies that destroy these harmful substances. Aging Changes and Their Effects on the Immune System ...

  20. Aging According to Biography.

    Science.gov (United States)

    Weiland, Steven

    1989-01-01

    Uses Erik Erikson's work to discuss how biographies treat aging. Explores how developmental theorists observe biographical representations of the life cycle and its applicability to aging. (Author/BHK)

  1. Corrected Age for Preemies

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Ages & Stages Prenatal Baby Bathing & Skin Care Breastfeeding Crying & ... Listen Español Text Size Email Print Share Corrected Age For Preemies Page Content Article Body If your ...

  2. Ages and Stages: Teen

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Ages & Stages Prenatal Baby Toddler Preschool Gradeschool Teen Dating & ... Safety School Substance Abuse Young Adult Healthy Children > Ages & Stages > Teen Teen Article Body Adolescence can be ...

  3. Polyphenols and Aging

    OpenAIRE

    Queen, Brannon L.; Tollefsbol, Trygve O.

    2010-01-01

    Age-associated changes within an individual are inherently complex and occur at multiple levels of organismal function. The overall decline in function of various tissues is known to play a key role in both aging and the complex etiology of certain age-associated diseases such as Alzheimer’s disease (AD) and cancer. Continuing research highlights the dynamic capacity of polyphenols to protect against age-associated disorders through a variety of important mechanisms. Numerous lines of evidenc...

  4. From QCD to Physical Resonances

    CERN Document Server

    Bolton, Daniel R; Wilson, David J

    2016-01-01

    In this talk, we present the first chiral extrapolation of a resonant scattering amplitude obtained from lattice QCD. Finite-volume spectra, determined by the Hadron Spectrum Collaboration at $m_\\pi = 236$ MeV, for the isotriplet $\\pi\\pi$ channel are analyzed using the L\\"uscher method to determine the infinite-volume scattering amplitude. Unitarized Chiral Perturbation Theory is then used to extrapolate the scattering amplitude to the physical light quark masses. The viability of this procedure is demonstrated by its agreement with the experimentally determined scattering phase shift up to center-of-mass energies of 1.2 GeV. Finally, we analytically continue the amplitude to the complex plane to obtain the $\\rho$-pole at $\\left[755(2)(1)\\left({}^{20}_{02}\\right) - \\frac{i}{2} 129(3)(1)\\left({}^7_1\\right)\\right]$ MeV.

  5. Second order resonant Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Cristobal, A.; Catarero, A. [Valencia Univ. (Spain). Dept. de Fisica Aplicada; Trallero-Giner, C. [Instituto Politecnico Nacional, Mexico City (Mexico). Centro de Investigacion y de Estudios Avanzados

    1996-03-01

    A theoretical model for resonant Raman scattering by two optical phonons in zincblende-type semiconductors is presented. The effect of Coulomb interaction between electrons and holes is taken into account by introducing discrete and continuous excitonic intermediate states. The model can be applied for laser frequencies below and above the band gap. We consider deformation potential and Froehlich interaction for the electron-one-phonon coupling. The absolute value of the scattering efficiency is evaluated for the L-O-phonons, TO-plus LO-phonon and two-TO-photons Raman processes, around the E{sub o} absorption edge of II-VI compound semiconductors. Comparison with the electron-hole uncorrelated theory and experimental data emphasizes the role if the excitonic effects. (author). 10 refs., 2 figs.

  6. A resonance mechanism of earthquakes

    CERN Document Server

    Flambaum, V V

    2015-01-01

    It had been observed in [1] that there are periodic 4-6 hours pulses of ? 200 ?Hz seismogravita- tional oscillations ( SGO ) before 95 % of powerful earthquakes. We explain this by beating between an oscillation eigenmode of a whole tectonic plate and a local eigenmode of an active zone which tranfers the oscillation energy from the tectonic plate to the active zone causing the eathrquake. Oscillation frequencies of the plate and ones of the active zone are tuned to a resonance by an additional pressure applied to the active zone due to collision of neighboring plates or convection in the upper mantia (plume). Corresponding theory may be used for short-term prediction of the earthquakes and tsunami.

  7. Resonant magnetic fields from inflation

    CERN Document Server

    Byrnes, Christian T; Jain, Rajeev Kumar; Urban, Federico R

    2012-01-01

    We propose a novel scenario to generate primordial magnetic fields during inflation induced by an oscillating coupling of the electromagnetic field to the inflaton. This resonant mechanism has two key advantages over previous proposals. First of all, it generates a narrow band of magnetic fields at any required wavelength, thereby allaying the usual problem of a strongly blue spectrum and its associated backreaction. Secondly, it avoids the need for a strong coupling as the coupling is oscillating rather than growing or decaying exponentially. Despite these major advantages, we find that the backreaction is still far too large during inflation if the generated magnetic fields are required to have a strength of ${\\cal O}(10^{-15}\\, \\Gauss)$ today on observationally interesting scales. We provide a more general no-go argument, proving that this problem will apply to any model in which the magnetic fields are generated on subhorizon scales and freeze after horizon crossing.

  8. Introduction to Nuclear Magnetic Resonance

    Science.gov (United States)

    Manatt, Stanley L.

    1985-01-01

    The purpose of this paper is to try to give a short overview of what the status is on nuclear magnetic resonance (NMR). It's a subject where one really has to spend some time to look at the physics in detail to develop a proper working understanding. I feel it's not appropriate to present to you density matrices, Hamiltonians of all sorts, and differential equations representing the motion of spins. I'm really going to present some history and status, and show a few very simple concepts involved in NMR. It is a form of radio frequency spectroscopy and there are a great number of nuclei that can be studied very usefully with the technique. NMR requires a magnet, a r.f. transmitter/receiver system, and a data acquisition system.

  9. Piezoelectric Resonator with Two Layers

    Science.gov (United States)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  10. Regular Motions of Resonant Asteroids

    Science.gov (United States)

    Ferraz-Mello, S.

    1990-11-01

    RESUMEN. Se revisan resultados analiticos relativos a soluciones regulares del problema asteroidal eliptico promediados en la vecindad de una resonancia con jupiten Mencionamos Ia ley de estructura para libradores de alta excentricidad, la estabilidad de los centros de liberaci6n, las perturbaciones forzadas por la excentricidad de jupiter y las 6rbitas de corotaci6n. ABSTRAC This paper reviews analytical results concerning the regular solutions of the elliptic asteroidal problem averaged in the neighbourhood of a resonance with jupiter. We mention the law of structure for high-eccentricity librators, the stability of the libration centers, the perturbations forced by the eccentricity ofjupiter and the corotation orbits. Key words: ASThROIDS

  11. Enhanced responsivity resonant RF photodetectors.

    Science.gov (United States)

    Liu, R; Dev, S; Zhong, Y; Lu, R; Streyer, W; Allen, J W; Allen, M S; Wenner, B R; Gong, S; Wasserman, D

    2016-11-14

    The responsivity of room-temperature, semiconductor-based photodetectors consisting of resonant RF circuits coupled to microstrip buslines is investigated. The dependence of the photodetector response on the semiconductor material and RF circuit geometry is presented, as is the detector response as a function of the spatial position of the incident light. We demonstrate significant improvement in detector response by choice of photoconductive material, and for a given material, by positioning our optical signal to overlap with positions of RF field enhancement. Design of RF circuits with strong field enhancement are demonstrated to further improve detector response. The improved detector response demonstrated offers opportunities for applications in RF photonics, materials metrology, or single read-out multiplexed detector arrays.

  12. Multi-resonance split ring resonator structures at sub-terahertz frequencies

    CERN Document Server

    Galal, Hossam

    2016-01-01

    This paper reports on the computational development of novel architectures of multi-resonance Split Ring Resonators (SRRs), for efficient manipulation of Terahertz (THz) frequency beams. The conceived resonators are based on both a capacitive and inductive scheme. Simulation results have been obtained for a 60 GHz to 240 GHz operational bandwidth.

  13. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan; Strulik, Holger

    the representative consumer is subject to physiological aging. In modeling aging we draw on recent research in the fields of biology and medicine. The speed of the aging process, and thus the time of death, are endogenously determined by optimal health investments. We calibrate the model to US data and proceed...

  14. Optimal Aging and Death

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Strulik, Holger

    2010-01-01

    This study introduces physiological aging into a simple model of optimal intertemporal consumption. In this endeavor we draw on the natural science literature on aging. According to the purposed theory, the speed of the aging process and the time of death are endogenously determined by optimal...

  15. Language and Aging.

    Science.gov (United States)

    Kemper, Susan; Anagnopoulos, Cheryl

    1989-01-01

    Reviews the effects of aging on language usage focusing on three areas of exploration: (1) changes in language in relation to changes in other cognitive abilities, (2) the linguistic consequences of normal aging versus those of dementia and aphasia, and (3) age-group differences in patterns of conversational interaction. (67 references) (GLR)

  16. Skin Care and Aging

    Science.gov (United States)

    ... version of this page please turn Javascript on. Skin Care and Aging How Aging Affects Skin Your skin changes with age. It becomes thinner, ... to make it feel and look better. Dry Skin and Itching Click for more information Many older ...

  17. Peroxisomes in yeast ageing

    NARCIS (Netherlands)

    Kumar, Sanjeev

    2015-01-01

    Ageing is characterized by the progressive decline in cellular functions that eventually leads to death. In human, ageing is associated with several age-related diseases such as cancer, cardiovascular disorders and neurodegenerative diseases. Over the years, research performed in several simpler sho

  18. Methods for age estimation

    Directory of Open Access Journals (Sweden)

    D. Sümeyra Demirkıran

    2014-03-01

    Full Text Available Concept of age estimation plays an important role on both civil law and regulation of criminal behaviors. In forensic medicine, age estimation is practiced for individual requests as well for request of the court. In this study it is aimed to compile the methods of age estimation and to make recommendations for the solution of the problems encountered. In radiological method the epiphyseal lines of the bones and views of the teeth are used. In order to estimate the age by comparing bone radiographs; Greulich-Pyle Atlas (GPA, Tanner-Whitehouse Atlas (TWA and “Adli Tıpta Yaş Tayini (ATYT” books are used. Bone age is found to be 2 years older averagely than chronologic age, especially in puberty, according to the forensic age estimations described in the ATYT book. For the age estimation with teeth, Demirjian method is used. In time different methods are developed by modifying Demirjian method. However no accurate method was found. Histopathological studies are done on bone marrow cellularity and dermis cells. No correlation was found between histopathoogical findings and choronologic age. Important ethical and legal issues are brought with current age estimation methods especially in teenage period. Therefore it is required to prepare atlases of bone age compatible with our society by collecting the findings of the studies in Turkey. Another recommendation could be to pay attention to the courts of age raising trials of teenage women and give special emphasis on birth and population records

  19. Neutron Resonance Parameters for Ra-226 (Radium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Ra-226 (Radium).

  20. Magnetic resonance imaging of the prostate

    DEFF Research Database (Denmark)

    Iversen, P; Kjaer, L; Thomsen, C

    1988-01-01

    Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate....

  1. Magnetic resonance imaging of the prostate

    DEFF Research Database (Denmark)

    Iversen, P; Kjaer, L; Thomsen, C

    1987-01-01

    Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate....

  2. Simple classical approach to spin resonance phenomena

    DEFF Research Database (Denmark)

    Gordon, R A

    1977-01-01

    A simple classical method of describing spin resonance in terms of the average power absorbed by a spin system is discussed. The method has several advantages over more conventional treatments, and a number of important spin resonance phenomena, not normally considered at the introductory level...

  3. Higher order resonances in dynamical systems

    CERN Document Server

    Contopoulos, George

    1978-01-01

    It is shown that the appearance of higher order resonances (that produce higher order islands on a surface of section), is not an indication of non-integrability. Examples are given and a method is described for constructing integrable Hamiltonians with higher order resonances. (11 refs).

  4. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

    Science.gov (United States)

    McQuarrie, Donald A.

    1988-01-01

    Discusses how to interpret nuclear magnetic resonance (NMR) spectra and how to use them to determine molecular structures. This discussion is limited to spectra that are a result of observation of only the protons in a molecule. This type is called proton magnetic resonance (PMR) spectra. (CW)

  5. Effect of Systematic Resonance on DBD Device

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Abnormal phenomena that discharge performance declines with the increase in the frequency of power supply have been observed in many DBD devices. DBD systematic resonance formed by transformer leakage induction and equivalent capacitance of the dielectric layer is a key factor causing such abnormal phenomena. Therefore, the parameters of a DBD device should be optimized to avoid resonance damage and improve DBD discharge characteristics.

  6. Optimal resonant control of flexible structures

    DEFF Research Database (Denmark)

    Krenk, Steen; Høgsberg, Jan Becker

    2009-01-01

    When introducing a resonant controller for a particular vibration mode in a structure this mode splits into two. A design principle is developed for resonant control based oil equal damping of these two modes. First the design principle is developed for control of a system with a single degree of...

  7. On the nature of the Roper resonance

    CERN Document Server

    Alvarez-Ruso, L

    2010-01-01

    The lightest N* state, N(1440) P11, also known as Roper resonance, has puzzled physicists for decades. A large variety of theoretical models aimed to understand its properties have been proposed. Some of them are briefly reviewed here, together with the hadronic processes where the Roper resonance is revealed or plays an important role.

  8. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    Science.gov (United States)

    Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

    2008-01-01

    The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

  9. Matrix methods for bare resonator eigenvalue analysis.

    Science.gov (United States)

    Latham, W P; Dente, G C

    1980-05-15

    Bare resonator eigenvalues have traditionally been calculated using Fox and Li iterative techniques or the Prony method presented by Siegman and Miller. A theoretical framework for bare resonator eigenvalue analysis is presented. Several new methods are given and compared with the Prony method.

  10. UV, stress and aging.

    Science.gov (United States)

    Debacq-Chainiaux, Florence; Leduc, Cedric; Verbeke, Alix; Toussaint, Olivier

    2012-07-01

    Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic-also called "photo-aging"-resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on the cell type (fibroblasts or keratinocytes, normal or immortalized) and the type of UV used (UVA or UVB).

  11. Normal cognitive aging.

    Science.gov (United States)

    Harada, Caroline N; Natelson Love, Marissa C; Triebel, Kristen L

    2013-11-01

    Even those who do not experience dementia or mild cognitive impairment may experience subtle cognitive changes associated with aging. Normal cognitive changes can affect an older adult's everyday function and quality of life, and a better understanding of this process may help clinicians distinguish normal from disease states. This article describes the neurocognitive changes observed in normal aging, followed by a description of the structural and functional alterations seen in aging brains. Practical implications of normal cognitive aging are then discussed, followed by a discussion of what is known about factors that may mitigate age-associated cognitive decline.

  12. Heart Age PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2015-09-01

    This 60 second public service announcement is based on the September 2015 CDC Vital Signs report. Your heart age is the age of your heart and blood vessels as a result of your risk factors for heart attack and stroke. If you smoke or have high blood pressure, your heart age will be much higher than your actual age. Learn what you can do to lower your heart age and keep it low.  Created: 9/1/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 9/1/2015.

  13. Thermally actuated resonant silicon crystal nanobalances

    Science.gov (United States)

    Hajjam, Arash

    As the potential emerging technology for next generation integrated resonant sensors and frequency references as well as electronic filters, micro-electro-mechanical resonators have attracted a lot of attention over the past decade. As a result, a wide variety of high frequency micro/nanoscale electromechanical resonators have recently been presented. MEMS resonators, as low-cost highly integrated and ultra-sensitive mass sensors, can potentially provide new opportunities and unprecedented capabilities in the area of mass sensing. Such devices can provide orders of magnitude higher mass sensitivity and resolution compared to Film Bulk Acoustic resonators (FBAR) or the conventional quartz and Surface Acoustic Wave (SAW) resonators due to their much smaller sizes and can be batch-fabricated and utilized in highly integrated large arrays at a very low cost. In this research, comprehensive experimental studies on the performance and durability of thermally actuated micromechanical resonant sensors with frequencies up to tens of MHz have been performed. The suitability and robustness of the devices have been demonstrated for mass sensing applications related to air-borne particles and organic gases. In addition, due to the internal thermo-electro-mechanical interactions, the active resonators can turn some of the consumed electronic power back into the mechanical structure and compensate for the mechanical losses. Therefore, such resonators can provide self-sustained-oscillation without the need for any electronic circuitry. This unique property has been deployed to demonstrate a prototype self-sustained sensor for air-borne particle monitoring. I have managed to overcome one of the obstacles for MEMS resonators, which is their relatively poor temperature stability. This is a major drawback when compared with the conventional quartz crystals. A significant decrease of the large negative TCF for the resonators has been attained by doping the devices with a high

  14. Coupling Bright and Dark Plasmonic Lattice Resonances

    CERN Document Server

    Rodriguez, S R K; Maes, B; Janssen, O T A; Vecchi, G; Rivas, J Gomez

    2011-01-01

    We demonstrate the coupling of bright and dark Surface Lattice Resonances (SLRs), which are collective Fano resonances in 2D plasmonic crystals. As a result of this coupling, a frequency stop-gap in the dispersion relation of SLRs is observed. The different field symmetries of the low and high frequency SLR bands lead to pronounced differences in their coupling to free space radiation. Standing waves of very narrow spectral width compared to localized surface plasmon resonances are formed at the high frequency band edge, while subradiant damping onsets at the low frequency band edge leading the resonance into darkness. We introduce a coupled oscillator analog to the plasmonic crystal, which serves to elucidate the physics of the coupled plasmonic resonances and to estimate very high quality factors (Q>700) for SLRs, which are the highest known for any 2D plasmonic crystal.

  15. Coherent and incoherent processes in resonant photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Magnuson, M.; Karis, O.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    In this contribution the authors present the distinction between coherent and incoherent processes in resonant photoemission. As a first step they determine whether an autoionization process is photoemission-like or Auger-like. The discussion is based on measurements for a weakly bonded adsorption system, Ar/Pt(111). This type of system is well adapted to investigate these effects since it yields distinctly shifted spectral features depending on the nature of the process. After this, the question of resonance photoemission in metallic systems is addressed. This is done in connection with measurements at the 2p edges for Ni metal. Ni has been one of the prototype systems for resonant photoemission. The resonances have been discussed in connection with the strong correlation and d-band localization effects in this system. Based on the results some general comments about the appearance of resonant effects in metallic systems are made.

  16. Hybrid simulation of electron cyclotron resonance heating

    CERN Document Server

    Ropponen, T; Suominen, P; Koponen, T K; Kalvas, T; Koivisto, H

    2008-01-01

    Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron density profiles and uses right hand circularly polarized (RHCP) electromagnetic waves to simulate electron heating in ECRIS plasma.

  17. Resonant superfluidity in an optical lattice

    Energy Technology Data Exchange (ETDEWEB)

    Titvinidze, Irakli; Hofstetter, Walter [Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, 60438 Frankfurt am Main (Germany); Snoek, Michiel [Institute for Theoretical Physics, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands)

    2010-07-01

    We study a system of ultracold fermionic Potassium ({sup 40}K) atoms in a three-dimensional optical lattice in the neighborhood of an s-wave Feshbach resonance. Close to resonance, the system is described by a multi-band Bose-Fermi Hubbard Hamiltonian. We derive an effective lowest-band Hamiltonian in which the effect of the higher band is incorporated by a self-consistent mean-field approximation. The resulting model is solved by means of Generalized Dynamical Mean-Field Theory. In addition to the BEC/BCS crossover we find on the BCS side of the resonance a phase transition to a fermionic Mott insulator at half filling, induced by the repulsive fermionic background scattering length. We also calculate the critical temperature of the BEC/BCS-state across the resonance and find it to be minimal at resonance.

  18. Observations of Snake Resonance in RHIC

    CERN Document Server

    Bai, Mei; Lee, Shyh-Yuan; Lin, Fanglei; MacKay, William; Ptitsyn, Vadim; Roser, Thomas; Tepikian, Steven

    2005-01-01

    Siberian snakes now become essential in the polarized proton acceleration. With proper configuration of Siberian snakes, the spin precession tune of the beam becomes $\\frac{1}{2}$ which avoids all the spin depolarizing resonance. However, the enhancement of the perturbations on the spin motion can still occur when the betatron tune is near some low order fractional numbers, called snake resonances, and the beam can be depolarized when passing through the resonance. The snake resonances have been confirmed in the spin tracking calculations, and observed in RHIC with polarized proton beam. Equipped with two full Siberian snakes in each ring, RHIC provides us a perfect facility for snake resonance studies. This paper presents latest experimental results. New insights are also discussed.

  19. Silicon on Nothing Mems Electromechanical Resonator

    CERN Document Server

    Durand, C; Ancey, P; Judong, F; Talbot, A; Quenouillere, R; Renaud, D; Borel, S; Florin, B; Buchaillot, L

    2008-01-01

    The very significant growth of the wireless communication industry has spawned tremendous interest in the development of high performances radio frequencies (RF) components. Micro Electro Mechanical Systems (MEMS) are good candidates to allow reconfigurable RF functions such as filters, oscillators or antennas. This paper will focus on the MEMS electromechanical resonators which show interesting performances to replace SAW filters or quartz reference oscillators, allowing smaller integrated functions with lower power consumption. The resonant frequency depends on the material properties, such as Young's modulus and density, and on the movable mechanical structure dimensions (beam length defined by photolithography). Thus, it is possible to obtain multi frequencies resonators on a wafer. The resonator performance (frequency, quality factor) strongly depends on the environment, like moisture or pressure, which imply the need for a vacuum package. This paper will present first resonator mechanisms and mechanical...

  20. Tunable Magnetic Resonance in Microwave Spintronics Devices

    Science.gov (United States)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  1. Aging, longevity and health.

    Science.gov (United States)

    Rasmussen, Lene Juel; Sander, Miriam; Wewer, Ulla M; Bohr, Vilhelm A

    2011-10-01

    The IARU Congress on Aging, Longevity and Health, held on 5-7 October 2010 in Copenhagen, Denmark, was hosted by Rector Ralf Hemmingsen, University of Copenhagen and Dean Ulla Wewer, Faculty of Health Sciences, University of Copenhagen and was organized by Center for Healthy Aging (CEHA) under the leadership of CEHA Managing Director Lene Juel Rasmussen and Prof. Vilhelm Bohr, National Institute on Aging, NIH, Baltimore, USA (associated to CEHA). The Congress was attended by approximately 125 researchers interested in and/or conducting research on aging and aging-related topics. The opening Congress Session included speeches by Ralf Hemmingsen, Ulla Wewer, and Lene Juel Rasmussen and Keynote Addresses by four world renowned aging researchers: Povl Riis (The Age Forum), Bernard Jeune (University of Southern Denmark), George Martin (University of Washington, USA) and Jan Vijg (Albert Einstein School of Medicine, USA) as well as a lecture discussing the art-science interface by Thomas Söderqvist (Director, Medical Museion, University of Copenhagen). The topics of the first six Sessions of the Congress were: Neuroscience and DNA damage, Aging and Stress, Life Course, Environmental Factors and Neuroscience, Muscle and Life Span and Life Span and Mechanisms. Two additional Sessions highlighted ongoing research in the recently established Center for Healthy Aging at the University of Copenhagen. This report highlights outcomes of recent research on aging-related topics, as described at the IARU Congress on Aging, Longevity and Health.

  2. Ageing and neurodegenerative diseases.

    Science.gov (United States)

    Hung, Chia-Wei; Chen, Yu-Chih; Hsieh, Wan-Ling; Chiou, Shih-Hwa; Kao, Chung-Lan

    2010-11-01

    Ageing, which all creatures must encounter, is a challenge to every living organism. In the human body, it is estimated that cell division and metabolism occurs exuberantly until about 25 years of age. Beyond this age, subsidiary products of metabolism and cell damage accumulate, and the phenotypes of ageing appear, causing disease formation. Among these age-related diseases, neurodegenerative diseases have drawn a lot of attention due to their irreversibility, lack of effective treatment, and accompanied social and economical burdens. In seeking to ameliorate ageing and age-related diseases, the search for anti-ageing drugs has been of much interest. Numerous studies have shown that the plant polyphenol, resveratrol (3,5,4'-trihydroxystilbene), extends the lifespan of several species, prevents age-related diseases, and possesses anti-inflammatory, and anti-cancer properties. The beneficial effects of resveratrol are believed to be associated with the activation of a longevity gene, SirT1. In this review, we discuss the pathogenesis of age-related neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and cerebrovascular disease. The therapeutic potential of resveratrol, diet and the roles of stem cell therapy are discussed to provide a better understanding of the ageing mystery.

  3. Comparison of cable ageing

    Science.gov (United States)

    Plaček, Vít; Kohout, Tomáš

    2010-03-01

    Two cable types, which currently are used in nuclear power plants (NPP) and which are composed by jacket/insulation materials, i.e. PVC/PVC and PVC/PE, were exposed to accelerated ageing conditions, in order to simulate their behavior after 10 years in service. The cables were aged under two different test conditions: With relatively high accelerating ageing speed:Radiation ageing was carried out at room temperature at a dose rate of 2900 Gy/h, followed by thermal ageing at 100 °C. This accelerated ageing condition was fairly fast, but still in compliance with the standards. With moderate ageing speed:The radiation and thermal ageing was performed simultaneously (superimposed) at a dose rate of 2.7-3.7Gy/h and a temperature of 68-70 °C. Such a test condition seems to be very close to the radiation and temperature impact onto the cables in the real NPP service. Finally, mechanical properties were measured to characterize the ageing status of the cables. The purpose of this study was to compare degradation effects, derived from both ageing methods, and to demonstrate that results obtained from high values of accelerating parameters and from fast ageing simulation can be very different from reality. The observed results corroborated this assumption.

  4. Ages of young stars

    CERN Document Server

    Soderblom, David R; Jeffries, Rob D; Mamajek, Eric E; Naylor, Tim

    2013-01-01

    Determining the sequence of events in the formation of stars and planetary systems and their time-scales is essential for understanding those processes, yet establishing ages is fundamentally difficult because we lack direct indicators. In this review we discuss the age challenge for young stars, specifically those less than ~100 Myr old. Most age determination methods that we discuss are primarily applicable to groups of stars but can be used to estimate the age of individual objects. A reliable age scale is established above 20 Myr from measurement of the Lithium Depletion Boundary (LDB) in young clusters, and consistency is shown between these ages and those from the upper main sequence and the main sequence turn-off -- if modest core convection and rotation is included in the models of higher-mass stars. Other available methods for age estimation include the kinematics of young groups, placing stars in Hertzsprung-Russell diagrams, pulsations and seismology, surface gravity measurement, rotation and activ...

  5. Can aging be programmed?

    DEFF Research Database (Denmark)

    Kowald, Axel; Kirkwood, Thomas B. L.

    2016-01-01

    The evolution of the aging process has long been a biological riddle, because it is difficult to explain the evolution of a trait that has apparently no benefit to the individual. Over 60 years ago, Medawar realized that the force of natural selection declines with chronological age because...... of unavoidable environmental risks. This forms the basis of the mainstream view that aging arises as a consequence of a declining selection pressure to maintain the physiological functioning of living beings forever. Over recent years, however, a number of articles have appeared that nevertheless propose...... the existence of specific aging genes; that is, that the aging process is genetically programmed. If this view were correct, it would have serious implications for experiments to understand and postpone aging. Therefore, we studied in detail various specific proposals why aging should be programmed. We find...

  6. Low-Loss Polymer-Based Ring Resonator for Resonant Integrated Optical Gyroscopes

    Directory of Open Access Journals (Sweden)

    Guang Qian

    2014-01-01

    Full Text Available Waveguide ring resonator is the sensing element of resonant integrated optical gyroscope (RIOG. This paper reports a polymer-based ring resonator with a low propagation loss of about 0.476 dB/cm for RIOG. The geometrical parameters of the waveguide and the coupler of the resonator were optimally designed. We also discussed the optical properties and gyroscope performance of the polymer resonator which shows a high quality factor of about 105. The polymer-based RIOG exhibits a limited sensitivity of less than 20 deg/h for the low and medium resolution navigation systems.

  7. Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

    Directory of Open Access Journals (Sweden)

    Yongyao Chen

    2012-06-01

    Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

  8. Perceiving Age and Gender in Unfamiliar Faces: An fMRI Study on Face Categorization

    Science.gov (United States)

    Wiese, Holger; Kloth, Nadine; Gullmar, Daniel; Reichenbach, Jurgen R.; Schweinberger, Stefan R.

    2012-01-01

    Efficient processing of unfamiliar faces typically involves their categorization (e.g., into old vs. young or male vs. female). However, age and gender categorization may pose different perceptual demands. In the present study, we employed functional magnetic resonance imaging (fMRI) to compare the activity evoked during age vs. gender…

  9. Electron Spin Resonance at the Level of 1 04 Spins Using Low Impedance Superconducting Resonators

    Science.gov (United States)

    Eichler, C.; Sigillito, A. J.; Lyon, S. A.; Petta, J. R.

    2017-01-01

    We report on electron spin resonance measurements of phosphorus donors localized in a 200 μ m2 area below the inductive wire of a lumped element superconducting resonator. By combining quantum limited parametric amplification with a low impedance microwave resonator design, we are able to detect around 2 ×1 04 spins with a signal-to-noise ratio of 1 in a single shot. The 150 Hz coupling strength between the resonator field and individual spins is significantly larger than the 1-10 Hz coupling rates obtained with typical coplanar waveguide resonator designs. Because of the larger coupling rate, we find that spin relaxation is dominated by radiative decay into the resonator and dependent upon the spin-resonator detuning, as predicted by Purcell.

  10. Lateral acoustic wave resonator comprising a suspended membrane of low damping resonator material

    Science.gov (United States)

    Olsson, Roy H.; El-Kady; , Ihab F.; Ziaei-Moayyed, Maryam; Branch; , Darren W.; Su; Mehmet F.,; Reinke; Charles M.,

    2013-09-03

    A very high-Q, low insertion loss resonator can be achieved by storing many overtone cycles of a lateral acoustic wave (i.e., Lamb wave) in a lithographically defined suspended membrane comprising a low damping resonator material, such as silicon carbide. The high-Q resonator can sets up a Fabry-Perot cavity in a low-damping resonator material using high-reflectivity acoustic end mirrors, which can comprise phononic crystals. The lateral overtone acoustic wave resonator can be electrically transduced by piezoelectric couplers. The resonator Q can be increased without increasing the impedance or insertion loss by storing many cycles or wavelengths in the high-Q resonator material, with much lower damping than the piezoelectric transducer material.

  11. Study on resonance frequency distribution of high-overtone bulk acoustic resonators

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; WANG Zuoqing; ZHANG Shuyi

    2005-01-01

    Based on the method of characterizing piezo-films by the resonance frequency distributions, the factors influencing the resonance frequency distribution of a High-overtone Bulk Acoustic Resonator (HBAR) consisting of a piezoelectric thin film with twoelectrodes and a substrate are studied. Some HBARs are simulated. The results manifest that changing the acoustic impedance ratio of the substrate to piezo-film the distribution of the space of the parallel resonance frequency and the effective electromechanical coupling factor are changed. When the fundamental mode of the piezo-film is at high frequency, changing the acoustic impedance ratio of the electrode to piezo-film and the thickness of the electrodes make the resonance frequency distribution of HBARs change. These results manifest that the HBARs can be resonant at specified frequencies by means of adjusting the factors affecting the resonance frequency distribution.

  12. Filling defect artefacts in magnetic resonance urography

    Energy Technology Data Exchange (ETDEWEB)

    Girish, G.; Chooi, W.K.; Morcos, S.K. [Department of Diagnostic Imaging, Northern General Hospital, Sheffield Teaching Hospitals NHS Trust, S5 7AU, Sheffield (United Kingdom)

    2004-01-01

    The aim of this study was to determine the prevalence of filling defect artefacts (FDA) in magnetic resonance urography (MRU). Retrospectively, we assessed MRU examinations of 45 patients with neurogenic bladder dysfunction (21 men, 24 women; mean age 35 years, age range 18-71 years). The MRU was performed 30 min after intramuscular injection of 20 mg frusemide using heavily T2-weighted fast-spin-echo techniques [axial, thick coronal slab, coronal maximum intensity projection (MIP) images] with fat saturation. The images were reviewed by two observers to determine the presence of filling defects and dilatation of pelvicalyceal system and ureters. The filling defects were classified into central, eccentric and complete. Clinical course and plain films were reviewed to determine significance of the detected filling defects. True filling defects were observed in 5 patients (11%) and all due to stones seen on the plain radiograph of the abdomen. Filling defects artefacts (FDAs) were seen in 23 patients (51%; 17 pelvicalyceal system, 17 upper third of ureters, 7 mid ureters and 1 distal ureter). No stones were seen on the plain radiograph of these patients and they had a favourable clinical course for over 24 months. The true filling defects were large in size, eccentric in position and seen in more than one sequence of the MRU examination (axial, n=5; slab, n=5; and MIP, n=4). Four (80%) of the patients with true defects and 21 (91%) of those with FDAs had dilatation of the pelvicalyceal system and ureters. The FDAs were small in size, centrally placed (74%) and always seen in axial images, rarely in slab images (2 cases) and not seen in MIP images. Artefactual filling defects can be seen in MRU examinations. The cause of the FDAs is not fully explained and could be secondary to turbulent and fast flow of the urine. Some of the FDAs seen in the calyces could be due to the tips of the papillae. Awareness of such defects obviates misinterpretation and prevents

  13. Ionization Cooling using Parametric Resonances

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland P.

    2008-06-07

    Ionization Cooling using Parametric Resonances was an SBIR project begun in July 2004 and ended in January 2008 with Muons, Inc., (Dr. Rolland Johnson, PI), and Thomas Jefferson National Accelerator Facility (JLab) (Dr. Yaroslav Derbenev, Subcontract PI). The project was to develop the theory and simulations of Parametric-resonance Ionization Cooling (PIC) so that it could be used to provide the extra transverse cooling needed for muon colliders in order to relax the requirements on the proton driver, reduce the site boundary radiation, and provide a better environment for experiments. During the course of the project, the theoretical understanding of PIC was developed and a final exposition is ready for publication. Workshops were sponsored by Muons, Inc. in May and September of 2007 that were devoted to the PIC technique. One outcome of the workshops was the interesting and somewhat unexpected realization that the beam emittances using the PIC technique can get small enough that space charge forces can be important. A parallel effort to develop our G4beamline simulation program to include space charge effects was initiated to address this problem. A method of compensating for chromatic aberrations by employing synchrotron motion was developed and simulated. A method of compensating for spherical aberrations using beamline symmetry was also developed and simulated. Different optics designs have been developed using the OptiM program in preparation for applying our G4beamline simulation program, which contains all the power of the Geant4 toolkit. However, no PIC channel design that has been developed has had the desired cooling performance when subjected to the complete G4beamline simulation program. This is believed to be the consequence of the difficulties of correcting the aberrations associated with the naturally large beam angles and beam sizes of the PIC method that are exacerbated by the fringe fields of the rather complicated channel designs that have been

  14. Theory and Applications of Surface Plasmon Resonance, Resonant Mirror, Resonant Waveguide Grating, and Dual Polarization Interferometry Biosensors

    Directory of Open Access Journals (Sweden)

    Billy W. Day

    2010-11-01

    Full Text Available Biosensors have been used extensively in the scientific community for several purposes, most notably to determine association and dissociation kinetics, protein-ligand, protein-protein, or nucleic acid hybridization interactions. A number of different types of biosensors are available in the field, each with real or perceived benefits over the others. This review discusses the basic theory and operational arrangements of four commercially available types of optical biosensors: surface plasmon resonance, resonant mirror, resonance waveguide grating, and dual polarization interferometry. The different applications these techniques offer are discussed from experiments and results reported in recently published literature. Additionally, recent advancements or modifications to the current techniques are also discussed.

  15. Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

    Institute of Scientific and Technical Information of China (English)

    Quan Jiang

    2016-01-01

    Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury, substantially improve functional outcome. We discuss and review state of the art magnetic resonance im-aging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

  16. The ionic mechanism of gamma resonance in rat striatal fast-spiking neurons

    OpenAIRE

    Sciamanna, Giuseppe; Wilson, Charles J.

    2011-01-01

    Striatal fast-spiking (FS) cells in slices fire in the gamma frequency range and in vivo are often phase-locked to gamma oscillations in the field potential. We studied the firing patterns of these cells in slices from rats ages 16–23 days to determine the mechanism of their gamma resonance. The resonance of striatal FS cells was manifested as a minimum frequency for repetitive firing. At rheobase, cells fired a doublet of action potentials or doublets separated by pauses, with an instantaneo...

  17. Aging and the aged in Aesopic fables.

    Science.gov (United States)

    Wortley, J

    1997-01-01

    Little attempt has been made to re-assess the attitudes to aging and old age of the ancient-medieval Greek-speaking world on the basis of the literary remains (which are common to both) since Richardson (1933). There are however some collections (proverbs, sayings, "purple passages" from literature and so forth) which include material revealing attitudes which are in fact quite different from those of today and which can even be surprising. One such collection, the large number of fables which more or less conform to the genre associated with Aesop, is here analyzed to isolate the texts which have to do with aging and the attitudes they reveal. Of the surprisingly few fables which touch upon the matter, most are distinctly complimentary. In most instances the elderly are seen to increase, rather diminish, in certain powers other than physical strength. Fables are found which characterize them as being astute, intelligent, crafty, loyal and, above all, capable of giving sound advice and good leadership when the situation requires it of them. The celebrated Fable of the Tortoise and the Hare, although it was not specifically interpreted in this way in ancient times, best sums up the general attitude: that dogged persistence (the characteristic of the elderly) will ultimately prove superior to all the erratic bursts of youthful speed anytime. Hence Cicero: "Old age is more spirited than youth, and stronger!"

  18. Magnetic resonance in Multiple Sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Scotti, G.; Scialfa, G.; Biondi, A.; Landoni, L.; Caputo, D.; Cazzullo, C.L.

    1986-07-01

    Magnetic Resonance Imaging was performed in more than 200 patients with clinical suspicion or knowledge of Multiple Sclerosis. One hundred and forty-seven (60 males and 87 females) had MR evidence of multiple sclerosis lesions. The MR signal of demyelinating plaques characteristically has prolonged T1 and T2 relaxation times and the T2-weighted spin-echo sequences are generally superior to the T1-weighted images because the lesions are better visualized as areas of increased signal intensity. MR is also able to detect plaques in the brainstem, cerebellum and within the cervical spinal cord. MR appears to be an important, non-invasive method for the diagnosis of Multiple Sclerosis and has proven to be diagnostically superior to CT, evoked potentials (EP) and CSF examination. In a selected group of 30 patients, with the whole battery of the relevant MS studies, MR was positive in 100%, CT in 33,3%, EP in 56% and CSF examination in 60%. In patients clinically presenting only with signs of spinal cord involvement or optic neuritis or when the clinical presentation is uncertain MR has proven to be a very useful diagnostic tool for diagnosis of MS by demonstrating unsuspected lesions in the cerebral hemispheres.

  19. String Resonances at Hadron Colliders

    CERN Document Server

    Anchordoqui, Luis A; Dai, De-Chang; Feng, Wan-Zhe; Goldberg, Haim; Huang, Xing; Lust, Dieter; Stojkovic, Dejan; Taylor, Tomasz R

    2014-01-01

    [Abridged] We consider extensions of the standard model based on open strings ending on D-branes. Assuming that the fundamental string mass scale M_s is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (3000 fb^{-1}) with \\sqrt{s} = 14 TeV, and at potential future pp colliders, HE-LHC and VLHC, operating at \\sqrt{s} = 33 and 100 TeV, respectively. In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and \\gamma + jet are completely independent of the details of compactification, and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV), lowest massive Regge exc...

  20. Aortic dissection: magnetic resonance imaging.

    Science.gov (United States)

    Amparo, E G; Higgins, C B; Hricak, H; Sollitto, R

    1985-05-01

    Fifteen patients with suspected or known aortic dissection were imaged with magnetic resonance (MR). Thirteen of these patients were eventually shown to have dissection. In most instances the diagnosis was established by aortography and/or computed tomography (CT) prior to the MR study. Surgical proof (6/13) and/or aortographic proof (10/13) were available in 11/13 patients with aortic dissection. MR demonstrated the intimal flap and determined whether the dissection was type A or type B. In addition, MR: differentiated between the true and false lumens; determined the origins of the celiac, superior mesenteric, and renal arteries from the true or false lumen in the cases where the dissection extended into the abdominal aorta (8/12); allowed post-surgical surveillance of the dissection; and identified aortoannular ectasia in the three patients who had Marfan syndrome. In addition to the 13 cases with dissection, there were two cases in whom the diagnosis of dissection was excluded by MR. Our early experience suggests that MR can serve as the initial imaging test in clinically suspected cases of aortic dissection and that the information provided by MR is sufficient to manage many cases. Additionally, MR obviates the use of iodinated contrast media.