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Sample records for frequency specific microcurrent

  1. Visceral and Somatic Disorders: Tissue Softening with Frequency-Specific Microcurrent

    OpenAIRE

    McMakin, Carolyn R.; Oschman, James L.

    2013-01-01

    Frequency-specific microcurrent (FSM) is an emerging technique for treating many health conditions. Pairs of frequencies of microampere-level electrical stimulation are applied to particular places on the skin of a patient via combinations of conductive graphite gloves, moistened towels, or gel electrode patches. A consistent finding is a profound and palpable tissue softening and warming within seconds of applying frequencies appropriate for treating particular conditions. Similar phenomena ...

  2. Visceral and somatic disorders: tissue softening with frequency-specific microcurrent.

    Science.gov (United States)

    McMakin, Carolyn R; Oschman, James L

    2013-02-01

    Frequency-specific microcurrent (FSM) is an emerging technique for treating many health conditions. Pairs of frequencies of microampere-level electrical stimulation are applied to particular places on the skin of a patient via combinations of conductive graphite gloves, moistened towels, or gel electrode patches. A consistent finding is a profound and palpable tissue softening and warming within seconds of applying frequencies appropriate for treating particular conditions. Similar phenomena are often observed with successful acupuncture, cranial-sacral, and other energy-based techniques. This article explores possible mechanisms involved in tissue softening. In the 1970s, neuroscientist and osteopathic researcher Irvin Korr developed a "γ-loop hypothesis" to explain the persistence of increased systemic muscle tone associated with various somatic dysfunctions. This article summarizes how physiologists, neuroscientists, osteopaths, chiropractors, and fascial researchers have expanded on Korr's ideas by exploring various mechanisms by which injury or disease increase local muscle tension or systemic muscle tone. Following on Korr's hypothesis, it is suggested that most patients actually present with elevated muscle tone or tense areas due to prior traumas or other disorders, and that tissue softening indicates that FSM or other methods are affecting the cause of their pathophysiology. The authors believe this concept and the research it has led to will be of interest to a wide range of energetic, bodywork, and movement therapists.

  3. Wound healing treatment by high frequency ultrasound, microcurrent, and combined therapy modifies the immune response in rats

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    Raciele I. G. Korelo

    2016-01-01

    Full Text Available BACKGROUND: Therapeutic high-frequency ultrasound, microcurrent, and a combination of the two have been used as potential interventions in the soft tissue healing process, but little is known about their effect on the immune system. OBJECTIVE: To evaluate the effects of therapeutic high frequency ultrasound, microcurrent, and the combined therapy of the two on the size of the wound area, peritoneal macrophage function, CD4+ and CD8+, T lymphocyte populations, and plasma concentration of interleukins (ILs. METHOD: Sixty-five Wistar rats were randomized into five groups, as follows: uninjured control (C, group 1, lesion and no treatment (L, group 2, lesion treated with ultrasound (LU, group 3, lesion treated with microcurrent (LM, group 4, and lesion treated with combined therapy (LUM, group 5. For groups 3, 4 and 5, treatment was initiated 24 hours after surgery under anesthesia and each group was allocated into three different subgroups (n=5 to allow for the use of the different therapy resources at on days 3, 7 and 14 Photoplanimetry was performed daily. After euthanasia, blood was collected for immune analysis. RESULTS: Ultrasound increased the phagocytic capacity and the production of nitric oxide by macrophages and induced the reduction of CD4+ cells, the CD4+/CD8+ ratio, and the plasma concentration of IL-1β. Microcurrent and combined therapy decreased the production of superoxide anion, nitric oxide, CD4+-positive cells, the CD4+/CD8+ ratio, and IL-1β concentration. CONCLUSIONS: Therapeutic high-frequency ultrasound, microcurrent, and combined therapy changed the activity of the innate and adaptive immune system during healing process but did not accelerate the closure of the wound.

  4. Microcurrent stimulation in the treatment of dry and wet macular degeneration

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    Chaikin L

    2015-12-01

    Full Text Available Laurie Chaikin,1 Kellen Kashiwa,2 Michael Bennet,2 George Papastergiou,3 Walter Gregory4 1Private practice, Alameda, CA, USA; 2Retina Institute of Hawaii, Honolulu, HI, USA; 3California Retinal Associates, San Diego, CA, USA; 4Clinical Trials Research Unit, Faculty of Medicine and Health, University of Leeds, Leeds, UK Purpose: To determine the safety and efficacy of the application of transcutaneous (transpalpebral microcurrent stimulation to slow progression of dry and wet macular degeneration or improve vision in dry and wet macular degeneration. Methods: Seventeen patients aged between 67 and 95 years with an average age of 83 years were selected to participate in the study over a period of 3 months in two eye care centers. There were 25 eyes with dry age-related macular degeneration (DAMD and six eyes with wet age-related macular degeneration (WAMD. Frequency-specific microcurrent stimulation was applied in a transpalpebral manner, using two programmable dual channel microcurrent units delivering pulsed microcurrent at 150 µA for 35 minutes once a week. The frequency pairs selected were based on targeting tissues, which are typically affected by the disease combined with frequencies that target disease processes. Early Treatment Diabetic Retinopathy Study or Snellen visual acuity (VA was measured before and after each treatment session. All treatment was administered in a clinical setting. Results: Significant increases were seen in VA in DAMD (P=0.012, Wilcoxon one-sample test, but in WAMD, improvements did not reach statistical significance (P=0.059. In DAMD eyes, twice as many patients showed increase in VA (52% compared to those showing deterioration (26%, with improvements being often sizeable, whereas deteriorations were usually very slight. In WAMD eyes, five of six (83% patients showed an increase and none showed deterioration. Conclusion: The substantial changes observed over this period, combined with continued improvement for

  5. Effects and mechanisms of a microcurrent dressing on skin wound healing: a review.

    Science.gov (United States)

    Yu, Chao; Hu, Zong-Qian; Peng, Rui-Yun

    2014-01-01

    The variety of wound types has resulted in a wide range of wound dressings, with new products frequently being introduced to target different aspects of the wound healing process. The ideal wound dressing should achieve rapid healing at a reasonable cost, with minimal inconvenience to the patient. Microcurrent dressing, a novel wound dressing with inherent electric activity, can generate low-level microcurrents at the device-wound contact surface in the presence of moisture and can provide an advanced wound healing solution for managing wounds. This article offers a review of the effects and mechanisms of the microcurrent dressing on the healing of skin wounds.

  6. Effects and mechanisms of a microcurrent dressing on skin wound healing: a review

    OpenAIRE

    Yu, Chao; Hu, Zong-Qian; Peng, Rui-Yun

    2014-01-01

    The variety of wound types has resulted in a wide range of wound dressings, with new products frequently being introduced to target different aspects of the wound healing process. The ideal wound dressing should achieve rapid healing at a reasonable cost, with minimal inconvenience to the patient. Microcurrent dressing, a novel wound dressing with inherent electric activity, can generate low-level microcurrents at the device-wound contact surface in the presence of moisture and can provide an...

  7. Silver-Coated Nylon Dressing Plus Active DC Microcurrent for Healing of Autogenous Skin Donor Sites

    Science.gov (United States)

    2013-08-01

    harvested; (c) bloodstream infection, burn-wound infection, hemodynamic instability requiring the use of pressors, or critical illness such as one...or nursing ; (h) sensitivity to silver or nylon; and (i) patient unable to provide written informed consent. Study Device The active microstimulator...the microcurrent stimulator. A research nurse monitored patient compli- ance by recording the amount of time the microcurrent stimulator was

  8. Comparative study of Low-level laser therapy and microcurrent on the healing of skin burns in rats

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    Rodrigo Pegado de Abreu Freitas

    2014-03-01

    This study investigated and compared the effects of low-level laser therapy (LLLT and microcurrent in the burn healing process in Wistar rats. We conducted a randomized controlled study with 30 rats divided into 3 groups (n = 10; control group (CG, laser group (LG and microcurrent group (MG. After thermal damage, 10 applications of 660 nm diode laser were performed in GL and 10 applications of 60 Hz microcurrent (160 μA in MG. The semi-quantitative histological analysis was done using scores (0–3, in sections stained by hematoxylin and eosin and Masson’s trichrome. The results indicated a significant improvement in the fibroblasts proliferation, collagen fibers deposition, neoangiogenesis, and cutaneous appendages regeneration in MG and LG. When microcurrent and LLLT were compared, no difference was detected, except the regeneration and formation of new cutaneous appendages, observed in MG. Despite the similar effects, GM showed faster tissue repair with the formation of skin appendages.

  9. Effects of microcurrent application and 670 nm InGaP low-level laser irradiation on experimental wound healing in healthy and diabetic Wistar rats

    International Nuclear Information System (INIS)

    Neves, L M G; Matheus, R L; Santos, G M T; Esquisatto, M A M; Amaral, M E C; Mendonça, F A S

    2013-01-01

    This study evaluated the effects of microcurrent application and 670 nm InGaP laser irradiation on wound healing in healthy and alloxan diabetic rats. The animals were divided into eight groups: healthy control (HC); diabetic control (DC); healthy treated with microcurrent (HMC); diabetic treated with microcurrent (DMC); healthy irradiated with laser (HL); diabetic irradiated with laser (DL); healthy receiving laser and microcurrent application (HLMC) and diabetic receiving laser and microcurrent application (DLMC). Wound samples were collected on days 2, 6, 10 and 14 of treatment for structural analysis, morphometry, and Western blotting to quantify the expression of TGF-β1 and VEGF. Comparison of animals receiving laser and microcurrent therapy showed a reduction in the number of inflammatory cells in diabetic animals, as well as an increase of fibroblasts in healthy animals and of newly formed vessels in healthy and diabetic animals. Expression of TGF-β1 was increased on day 6 in all groups, especially diabetic animals. A reduction in the expression of this protein was observed on day 10 in all groups. VEGF expression was higher on day 6 in treated and control diabetic animals when compared to healthy animals. Analysis of VEGF expression in the laser- and microcurrent-treated groups on day 10 showed a decrease in diabetic animals and an increase in healthy animals. In conclusion, laser therapy and microcurrent stimulation exert beneficial effects on wound healing in both healthy and diabetic animals. (paper)

  10. [Treatment with the use of microcurrent lymphatic drainage physiotherapy during the postoperative period following rhinoplastic surgery].

    Science.gov (United States)

    Aleksanyan, T A; Kazantsev, E V

    The objective of the present study was to evaluate the effectiveness of the combined treatment of the patients who had undergone either primary or secondary rhinoplastic surgery with the use of photo- and magnetic therapy in comparison with the effectiveness of phototherapy in the combination with microcurrent therapy. The patients were divided into four groups depending on the type of the surgical intervention and the mode of the combined physiotherapeutic treatment. All the patients were given combined physiotherapeutic treatment in addition to the standard pharmacotherapy starting from the second day of the postoperative period. The patients of groups 1 and 3 received phototherapy in the combination with magnetic therapy while those in groups 2 and 4 were treated by phototherapy in the combination with microcurrent lymphatic drainage physiotherapy. It was shown that the different combinations of physiotherapeutic modalities during the postoperative period following primary «closed» rhinoplasty were not different significantly in terms of effectiveness. After secondary «closed» rhinoplasty, the combination of phototherapy with the application of microcurrents looks more preferable. It is concluded that microcurrent lymphdraining physiotherapy should be regarded as the priority component of the combined physiotherapeutic treatment during the postoperative period following secondary «closed» rhinoplasty.

  11. Pilot study of impedance-controlled microcurrent therapy for managing radiation-induced fibrosis in head-and-neck cancer patients

    International Nuclear Information System (INIS)

    Lennox, Arlene J.; Shafer, Jeffrey P.; Hatcher, Madeline; Beil, Janice; Funder, Sandra J.

    2002-01-01

    Purpose: To evaluate the effectiveness of impedance-controlled microcurrent therapy for managing treatment sequelae in head-and-neck cancer patients. Methods and Materials: Between January 1998 and June 1999, 26 patients who were experiencing late effects of radiotherapy were treated b.i.d. with impedance-controlled microcurrent therapy for 1 week. Objective range-of-motion measurements were made for cervical rotation, extension/flexion, and lateral flexion before therapy, at the end of each treatment day, and monthly for 3 months. In addition, each patient's subjective complaints were tabulated before treatment and reevaluated at the last follow-up visit. No additional physical therapy or electrical stimulation was permitted during the follow-up period. Results: At the end of the course of microcurrent therapy, 92% of the 26 patients exhibited improved cervical rotation, 85% had improved cervical extension/flexion, and 81% had improved cervical lateral flexion. Twenty-two patients returned for the 3-month follow-up visit. Of these, 91% had maintained a cervical rotation range of motion greater than their pretherapy measurements. Eighty-two percent maintained improved cervical extension/flexion and 77% maintained improved lateral flexion. When the range-of-motion measurements were stratified by pretreatment severity (severe, moderate, mild, or asymptomatic), the degree of improvement directly correlated with the severity. Thus, patients who had more severe initial symptoms experienced a higher percentage of improvement than did those with milder symptoms. For these patients, the cervical rotation range of motion changed from a baseline of 59 deg. ± 12 deg. to 83 deg. ± 14 deg. at 3 months; flexion/extension improved from 47 deg. ± 10 deg. to 73 deg. ± 13 deg.; and lateral flexion went from 31 deg. ± 7 deg. to 48 deg. ± 9 deg. Some patients also reported symptom improvement for tongue mobility, facial asymmetry, xerostomia, cervical/facial muscle spasms

  12. Effects of microcurrent stimulation on Hyaline cartilage repair in immature male rats (Rattus norvegicus

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    de Campos Ciccone Carla

    2013-01-01

    Full Text Available Abstract Background In this study, we investigate the effects of microcurrent stimulation on the repair process of xiphoid cartilage in 45-days-old rats. Methods Twenty male rats were divided into a control group and a treated group. A 3-mm defect was then created with a punch in anesthetized animals. In the treated group, animals were submitted to daily applications of a biphasic square pulse microgalvanic continuous electrical current during 5 min. In each application, it was used a frequency of 0.3 Hz and intensity of 20 μA. The animals were sacrificed at 7, 21 and 35 days after injury for structural analysis. Results Basophilia increased gradually in control animals during the experimental period. In treated animals, newly formed cartilage was observed on days 21 and 35. No statistically significant differences in birefringent collagen fibers were seen between groups at any of the time points. Treated animals presented a statistically larger number of chondroblasts. Calcification points were observed in treated animals on day 35. Ultrastructural analysis revealed differences in cell and matrix characteristics between the two groups. Chondrocyte-like cells were seen in control animals only after 35 days, whereas they were present in treated animals as early as by day 21. The number of cuprolinic blue-stained proteoglycans was statistically higher in treated animals on days 21 and 35. Conclusion We conclude that microcurrent stimulation accelerates the cartilage repair in non-articular site from prepuberal animals.

  13. Effects of microcurrent stimulation on hyaline cartilage repair in immature male rats (Rattus norvegicus).

    Science.gov (United States)

    de Campos Ciccone, Carla; Zuzzi, Denise Cristina; Neves, Lia Mara Grosso; Mendonça, Josué Sampaio; Joazeiro, Paulo Pinto; Esquisatto, Marcelo Augusto Marretto

    2013-01-19

    In this study, we investigate the effects of microcurrent stimulation on the repair process of xiphoid cartilage in 45-days-old rats. Twenty male rats were divided into a control group and a treated group. A 3-mm defect was then created with a punch in anesthetized animals. In the treated group, animals were submitted to daily applications of a biphasic square pulse microgalvanic continuous electrical current during 5 min. In each application, it was used a frequency of 0.3 Hz and intensity of 20 μA. The animals were sacrificed at 7, 21 and 35 days after injury for structural analysis. Basophilia increased gradually in control animals during the experimental period. In treated animals, newly formed cartilage was observed on days 21 and 35. No statistically significant differences in birefringent collagen fibers were seen between groups at any of the time points. Treated animals presented a statistically larger number of chondroblasts. Calcification points were observed in treated animals on day 35. Ultrastructural analysis revealed differences in cell and matrix characteristics between the two groups. Chondrocyte-like cells were seen in control animals only after 35 days, whereas they were present in treated animals as early as by day 21. The number of cuprolinic blue-stained proteoglycans was statistically higher in treated animals on days 21 and 35. We conclude that microcurrent stimulation accelerates the cartilage repair in non-articular site from prepuberal animals.

  14. Electro-membrane microcurrent therapy reduces signs and symptoms of muscle damage.

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    Lambert, Michael I; Marcus, Paul; Burgess, Theresa; Noakes, Timothy D

    2002-04-01

    Delayed onset muscle soreness (DOMS) occurs after unaccustomed physical activity or competitive sport, resulting in stiff, painful muscles with impaired function. Acustat electro-membrane microcurrent therapy has been used to treat postoperative pain and soft tissue injury; however, its efficacy in reducing symptoms of muscle damage is not known. Thirty healthy men were recruited for a double-blind, placebo-controlled trial. The muscles of their nondominant arms were damaged using an eccentric-exercise protocol. Subjects were then randomly assigned to treatment with either Acustat or a matching placebo membrane for 96 h and monitored for a total of 168 h. Subjects in both groups experienced severe pain and swelling of the elbow flexors after the eccentric exercise. After 24 h, the elbow joint angle of the placebo group had increased significantly more than those in the Acustat group (13.7 +/- 8.9 degrees vs 7.5 +/- 5.5 degrees; placebo vs Acustat, P microcurrent therapy reduces the severity of the symptoms. The mechanisms of action are unknown but are likely related to maintenance of intracellular Ca2+ homeostasis after muscle damaging exercise.

  15. Application of 670 nm InGaP laser and microcurrent favors the healing of second-degree burns in Wistar rats

    International Nuclear Information System (INIS)

    Belli, M; Esquisatto, M A M; Amaral, M E C; Santos, G M T; Mendonça, F A S; Fernandes, C R; Neves, L M G; Mourão, V; Barbieri, R

    2015-01-01

    The treatment of burn wounds has been a challenge due to their severity and associated multiple complications, and represents a major public health problem. This study investigated the effects of 670 nm InGaP laser irradiation and microcurrent (10 µA) stimulation on the healing of second-degree burns inflicted on the back of Wistar rats. Seventy-two animals were divided into four groups: no treatment (C); animals irradiated with a 670 nm InGaP laser (L); animals receiving microcurrent stimulation (10 µA/3 min) (MC); animals receiving 670 nm InGaP laser therapy and microcurrent stimulation (10 µA/3 min) on alternate days (MCL). Wound samples were collected on days 7, 14 and 21 of treatment for structural and morphometric analysis and for Western blotting to quantify the expression of TGF-β1 and VEGF. The applied alone and alternate of laser and microcurrent reduced the number of inflammatory cells and increased the number of newly formed vessels and fibroblasts, collagen fiber content and fiber reorganization. The two treatments also favorably modified the expression of VEGF and TGF-β1, inducing angiogenesis and decreasing the inflammation time. (paper)

  16. Microcurrent Point Stimulation Applied to Lower Back Acupuncture Points for the Treatment of Nonspecific Neck Pain.

    Science.gov (United States)

    Armstrong, Kelly; Gokal, Raman; Chevalier, Antoine; Todorsky, William; Lim, Mike

    2017-04-01

    Although acupuncture and microcurrent are widely used for chronic pain, there remains considerable controversy as to their therapeutic value for neck pain. We aimed to determine the effect size of microcurrent applied to lower back acupuncture points to assess the impact on the neck pain. This was a cohort analysis of treatment outcomes pre- and postmicrocurrent stimulation, involving 34 patients with a history of nonspecific chronic neck pain. Consenting patients were enrolled from a group of therapists attending educational seminars and were asked to report pain levels pre-post and 48 hours after a single MPS application. Direct current microcurrent point stimulation (MPS) applied to standardized lower back acupuncture protocol points was used. Evaluations entailed a baseline visual analog scale (VAS) pain scale assessment, using a VAS, which was repeated twice after therapy, once immediately postelectrotherapy and again after a 48-h follow-up period. All 34 patients received a single MPS session. Results were analyzed using paired t tests. Results and Outcomes: Pain intensity showed an initial statistically significant reduction of 68% [3.9050 points; 95% CI (2.9480, 3.9050); p = 0.0001], in mean neck pain levels after standard protocol treatment, when compared to initial pain levels. There was a further statistically significant reduction of 35% in mean neck pain levels at 48 h when compared to pain levels immediately after standard protocol treatment [0.5588 points; 95% CI (0.2001, 0.9176); p = 0.03], for a total average pain relief of 80%. The positive results in this study could have applications for those patients impacted by chronic neck pain.

  17. The Influence of High-Frequency Gravitational Waves Upon Muscles

    International Nuclear Information System (INIS)

    Moy, Lawrence S.; Baker, Robert M. L. Jr

    2007-01-01

    The objective of this paper is to present a theory for the possible influence of high-frequency gravitational waves or HFGWs and pulsed micro-current electromagnetic waves or EMs on biological matter specifically on muscle cells and myofibroblasts. The theory involves consideration of the natural frequency of contractions and relaxations of muscles, especially underlying facial skin, and the possible influence of HFGWs on that process. GWs pass without attenuation through all material thus conventional wisdom would dictate that GWs would have no influence on biological matter. On the other hand, GWs can temporarily modify a gravitational field in some locality if they are of high frequency and such a modification might have an influence in changing the skin muscles' natural frequency. Prior to the actual laboratory generation of HFGWs their influence can be emulated by micro-current EM pulses to the skin and some evidence presented here on that effect may predict the influence of HFGWs. We believe that the HFGW pulsations lead to increased muscle activity and may serve to reverse the aging process. A novel theoretical framework concerning these relaxation phenomena is one result of the paper. Another result is the analysis of the possible delivery system of the FBAR-generated HFGWs, the actual power of the generated HFGWs, and the system's application to nanostructural modification of the skin or muscle cells. It is concluded that a series of non-evasive experiments, which are identified, will have the potential to test theory by detecting and analyzing the possible HFGWs change in polarization, refraction, etc. after their interaction with the muscle cells

  18. Comparative study of the application of microcurrent and AsGa 904 nm laser radiation in the process of repair after calvaria bone excision in rats

    International Nuclear Information System (INIS)

    Mendonça, J S; Neves, L M G; Esquisatto, M A M; Mendonça, F A S; Santos, G M T

    2013-01-01

    This study evaluated the effects of microcurrent stimulation (10 μA/5 min) and 904 nm GaAs laser irradiation (3 J cm −2 for 69 s/day) on excisional lesions created in the calvaria bone of Wistar rats. The results showed significant responses in the reduction of inflammatory cells and an increase in the number of new blood vessels, number of fibroblasts and deposition of birefringent collagen fibers when these data were compared with those of samples of the untreated lesions. Both applications, microcurrent and laser at 904 nm, favored tissue repair in the region of bone excisions during the study period and these techniques can be used as coadjuvantes in the repair of bone tissue. (paper)

  19. Electric microcurrent in the restoration of the skin undergone a trichloroacetic acid peeling in rats Microcorrente elétrica na restauração da pele submetidos ao peeling de ácido tricloroacético em ratos

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    Vilma Natividade Silva Santos

    2004-10-01

    Full Text Available PURPOSE: To investigate the influence of neuromuscular electric stimulation by microcurrent (MENS - Microcurrent Electric Neuromuscular Stimulation in the restoration of the skin of rats undergone trichloroacetic acid (TCA. METHODS: Thirty-two hairless, male, adult rats were divided into two groups (with 16 animals each. In the Control Group (G1 the application of microcurrent was simulated 48 hours after the peeling. In the Experimental Group (G2 MENS was applied 48 hours after the TCA peeling, each 48 hours up to the Day 21, under the frequency of 0.5 Hz, intensity of 50mu A, and lasting 20 minutes. The area of the lesion was evaluated on Days 7, 14, and 21 after-peeling by the Paper Template Method, and on Day 21 the histological analysis was performed. RESULTS: On microscopy changes were seen in the fibroblasts amount and structure, and in the collagen of the experimental group, with statistically significant difference (pOBJETIVO: Investigar a influência da estimulação elétrica neuromuscular por microcorrente (MENS - Microcurrent Electric Neuromuscular Stimulation na restauração da pele de ratos submetidos ao peeling com ATA (ácido tricloroacético. MÉTODOS: Foram utilizados 32 ratos hair less machos adultos, separados em dois grupos (com 16 animais cada.No Grupo Controle (G1 foi simulada a aplicação da microcorrente 48 horas após o peeling. No Grupo Experimental (G2 a MENS foi aplicada 48 horas após o peeling com ATA, realizada, a cada 48 horas, até o 21º dia, com freqüência de 0,5 Hz, intensidade de 50mi A e duração de 20 minutos. Avaliou-se a área da lesão no 7º ,14º e 21º dia pós-peeling, com o Método Gabarito de Papel, e no 21º dia foi realizada a análise histológica. RESULTADOS: Na microscopia foram observadas modificações na quantidade e na estrutura dos fibroblastos, e no colágeno do Grupo Experimental em relação ao Grupo Controle. Pelo Método Gabarito de Papel, observou-se redução do tempo para a

  20. Effects of the application of Aloe vera (L. and microcurrent on the healing of wounds surgically induced in Wistar rats Efeitos da aplicação de Aloe vera (L. e microcorrente no reparo de lesões cirúrgicas induzidas em ratos Wistar

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    Cristina Cruz Franchini

    2009-04-01

    Full Text Available PURPOSE: To investigate the effects of topical application of an Aloe vera gel combined or not with microcurrent application on the healing of skin wounds surgically induced in Wistar rats. METHODS: The animals were randomly divided into the following groups: control group, animals topically treated with Aloe vera, animals treated with a microcurrent, and animals receiving topical application of Aloe vera combined with microcurrent application. RESULTS: The results indicated differences in wound healing between the various treatments when compared to the control group. Tissue hyperplasia was lower in the control group compared to the other treated groups. Accelerated wound healing was observed in the group treated with Aloe vera compared to control. Animals submitted to microcurrent application only and the group treated with microcurrent plus Aloe vera presented an earlier onset of the proliferative phase compared to the control group and animals treated with Aloe vera gel alone. Morphometric data confirmed the structural findings. CONCLUSION: Simultaneous application of Aloe vera gel and microcurrent is an excellent choice for the treatment of open wounds thus indicating a synergistic action of these two applications.OBJETIVO: Investigar os efeitos da aplicação tópica do gel de Aloe vera, combinada ou não com a aplicação de microcorrente no reparo de lesões cutâneas induzidas cirurgicamente em ratos Wistar. MÉTODOS: Os animais foram distribuídos aleatoriamente em: grupo controle, tratado topicamente com gel in natura de Aloe vera, tratado com microcorrente e tratado com aplicação tópica de Aloe vera associada à microcorrente. RESULTADOS: Os resultados do presente trabalho indicaram que o reparo tecidual ocorreu de forma diferenciada nos vários tratamentos empregados quando comparados ao grupo controle. A hiperplasia tecidual no grupo controle foi menor que a observada nos demais grupos tratados. No grupo tratado com aplica

  1. Note: A temperature-stable low-noise transimpedance amplifier for microcurrent measurement

    Science.gov (United States)

    Xie, Kai; Shi, Xueyou; Zhao, Kai; Guo, Lixin; Zhang, Hanlu

    2017-02-01

    Temperature stability and noise characteristics often run contradictory in microcurrent (e.g., pA-scale) measurement instruments because low-noise performance requires high-value resistors with relatively poor temperature coefficients. A low-noise transimpedance amplifier with high-temperature stability, which involves an active compensation mechanism to overcome the temperature drift mainly caused by high-value resistors, is presented. The implementation uses a specially designed R-2R compensating network to provide programmable current gain with extra-fine trimming resolution. The temperature drifts of all components (e.g., feedback resistors, operational amplifiers, and the R-2R network itself) are compensated simultaneously. Therefore, both low-temperature drift and ultra-low-noise performance can be achieved. With a current gain of 1011 V/A, the internal current noise density was about 0.4 fA/√Hz, and the average temperature coefficient was 4.3 ppm/K at 0-50 °C. The amplifier module maintains accuracy across a wide temperature range without additional thermal stabilization, and its compact size makes it especially suitable for high-precision, low-current measurement in outdoor environments for applications such as electrochemical emission supervision, air pollution particles analysis, radiation monitoring, and bioelectricity.

  2. Enhancement of delay eyelid conditioning by microcurrent electrical stimulation of the medial prefrontal cortex is triggered by the expression of Fos protein in guinea pigs

    OpenAIRE

    ZHENG, YA-JUAN; DONG, YU-CHEN; ZHU, CHAO; ZHAO, MEI-SHENG

    2016-01-01

    Eyelid conditioning, including delay eyelid conditioning and trace eyelid conditioning, has been used extensively to study neural structures and mechanisms of learning and memory as a form of associative learning. In the present study, microcurrent electrical stimulation was used to stimulate the medial prefrontal cortex (mPFC) to induce delay eyelid conditioning in guinea pigs. The acquisition rate and relative latency of the conditioned eyelid response (CR) and the startle eyelid response (...

  3. The modulative effects of microcurrent electrical nerve stimulation on diabetic mice.

    Science.gov (United States)

    Huang, Wen-Ching; Chang, Wen-Chieh; Hsu, Yi-Ju; Huang, Chun-Feng; Huang, Chi-Chang; Kao, Cheng-Yan; Lin, Che-Li

    2017-02-28

    Diabetes (one of non-communicable diseases) is serious due to its complications, such like, cardiovascular ailments, neuropathy, nephropathy, retinopathy, wound gangrene and sexual impotence. Diabetes and associated chronic conditions are rapidly emerging as major health problems. In clinical, there were different drugs for diabetes treatment on different mechanisms. However, there were limited studies on the efficacy of electric stimulations on diabetes therapeutic application. In current study, we try to evaluate the effect of microcurrent electrical nerve stimulator (MENS) on diabetes modulation as an alternative medicine. A total of 36 male ICR mice of 6 weeks old were randomly divided into 4 groups [1] Control, [2] MENS only, [3] DM, [4] DM with MENS. During 8 weeks treatments, the diabetes-associated assessments included body weight, diet utilization, blood glucose measurement, other biochemistries and histopathological observations. The diabetes animal model induced by STZ had 180 mg/dl fasting blood glucose (GLU-AC) before MENS intervention. After 3 and 6 weeks administration, the GLU-AC of DM+MENS group significantly decreased 31.97% and 50.82% (P < 0.0001), respectively, as compared to DM group and the OGTT also demonstrated the similar significant results. The diabetic syndromes of polydipsia and polyphagia were also significantly ameliorated by MENS intervention. In other biochemical indexes, the glycated hemoglobin (HbA1c), hyperinsulinemia, liver functions (AST & ALT) and kidneys function (BUN & Creatinine) were also significantly mitigated by MENS under diabetes model. The histological observation also showed the MENS administration improved the diabetes-related pathological characteristics in liver, kidney and pancreas tissues. Our results suggest that administration of MENS could significantly improve diabetes animal model on blood sugar homeostasis, diabetic polydipsia, biochemistries, and tissue damage. In the health conditions, the MENS didn

  4. Frequency-specific modulation of population-level frequency tuning in human auditory cortex

    Directory of Open Access Journals (Sweden)

    Roberts Larry E

    2009-01-01

    Full Text Available Abstract Background Under natural circumstances, attention plays an important role in extracting relevant auditory signals from simultaneously present, irrelevant noises. Excitatory and inhibitory neural activity, enhanced by attentional processes, seems to sharpen frequency tuning, contributing to improved auditory performance especially in noisy environments. In the present study, we investigated auditory magnetic fields in humans that were evoked by pure tones embedded in band-eliminated noises during two different stimulus sequencing conditions (constant vs. random under auditory focused attention by means of magnetoencephalography (MEG. Results In total, we used identical auditory stimuli between conditions, but presented them in a different order, thereby manipulating the neural processing and the auditory performance of the listeners. Constant stimulus sequencing blocks were characterized by the simultaneous presentation of pure tones of identical frequency with band-eliminated noises, whereas random sequencing blocks were characterized by the simultaneous presentation of pure tones of random frequencies and band-eliminated noises. We demonstrated that auditory evoked neural responses were larger in the constant sequencing compared to the random sequencing condition, particularly when the simultaneously presented noises contained narrow stop-bands. Conclusion The present study confirmed that population-level frequency tuning in human auditory cortex can be sharpened in a frequency-specific manner. This frequency-specific sharpening may contribute to improved auditory performance during detection and processing of relevant sound inputs characterized by specific frequency distributions in noisy environments.

  5. Effectiveness of transcutaneous electrical nerve stimulation and microcurrent electrical nerve stimulation in bruxism associated with masticatory muscle pain - A comparative study

    Directory of Open Access Journals (Sweden)

    Rajpurohit Bharat

    2010-01-01

    Full Text Available Objectives: To compare the effectiveness of transcutaneous electrical nerve stimulation (TENS and microcurrent electrical nerve stimulation (MENS on masticatory muscles pain bruxism patient. Materials and Methods : A total of 60 subjects with the clinical diagnosis of bruxism were randomly allocated to two study groups. Group A received TENS (50 Hz, pulse width 0.5 mSec, intensity 0-60 mA for 20 minutes for a period of seven days and Group B received MENS (0.5 Hz, intensity 1,000 μA for 20 minutes for a period of seven days. The outcome measures were assessed in term of Visual Analog Scale (VAS and digital pressometer of 2 Kgf. Results : The study showed significant change in intensity of pain as per VAS score ( P ≤ 0.0001 and tenderness as per digital pressometer ( P ≤ 0.0001. Conclusion : MENS could be used as an effective pain-relieving adjunct to TENS in the treatment of masticatory muscle pain due to bruxism.

  6. Ultra-low microcurrent in the management of diabetes mellitus, hypertension and chronic wounds: Report of twelve cases and discussion of mechanism of action

    Science.gov (United States)

    Lee, Bok Y.; AL-Waili, Noori; Stubbs, Dean; Wendell, Keith; Butler, Glenn; AL-Waili, Thia; AL-Waili, Ali

    2010-01-01

    Oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus and cardiovascular diseases including hypertension. The low levels of antioxidants accompanied by raised levels of markers of free radical damage play a major role in delaying wound healing. Ultra-low microcurrent presumably has an antioxidant effect, and it was shown to accelerate wound healing. The purpose of the study is to investigate the efficacy of ultra-low microcurrent delivered by the Electro Pressure Regeneration Therapy (EPRT) device (EPRT Technologies-USA, Simi Valley, CA) in the management of diabetes, hypertension and chronic wounds. The EPRT device is an electrical device that sends a pulsating stream of electrons in a relatively low concentration throughout the body. The device is noninvasive and delivers electrical currents that mimic the endogenous electric energy of the human body. It is a rechargeable battery-operated device that delivers a direct current (maximum of 3 milliAmperes) of one polarity for 11.5 minutes, which then switched to the opposite polarity for another 11.5 minutes. The resulting cycle time is approximately 23min or 0.000732 Hz and delivers a square wave bipolar current with a voltage ranging from 5V up to a maximum of 40 V. The device produces a current range of 3 mA down to 100 nA. Twelve patients with long standing diabetes, hypertension and unhealed wounds were treated with EPRT. The patients were treated approximately for 3.5 h/day/5 days a week. Assessment of ulcer was based on scale used by National Pressure Ulcer Advisory Panel Consensus Development Conference. Patients were followed-up with daily measurement of blood pressure and blood glucose level, and their requirement for medications was recorded. Treatment continued from 2-4 months according to their response. Results showed that diabetes mellitus and hypertension were well controlled after using this device, and their wounds were markedly healed (30-100%). The patients

  7. Monophasic Pulsed 200-μA Current Promotes Galvanotaxis With Polarization of Actin Filament and Integrin α2β1 in Human Dermal Fibroblasts.

    Science.gov (United States)

    Uemura, Mikiko; Maeshige, Noriaki; Koga, Yuka; Ishikawa-Aoyama, Michiko; Miyoshi, Makoto; Sugimoto, Masaharu; Terashi, Hiroto; Usami, Makoto

    2016-01-01

    The monophasic pulsed microcurrent is used to promote wound healing, and galvanotaxis regulation has been reported as one of the active mechanisms in the promotion of tissue repair with monophasic pulsed microcurrent. However, the optimum monophasic pulsed microcurrent parameters and intracellular changes caused by the monophasic pulsed microcurrent have not been elucidated in human dermal fibroblasts. The purpose of this study was to investigate the optimum intensity for promoting galvanotaxis and the effects of electrical stimulation on integrin α2β1 and actin filaments in human dermal fibroblasts. Human dermal fibroblasts were treated with the monophasic pulsed microcurrent of 0, 100, 200, or 300 μA for 8 hours, and cell migration and cell viability were measured 24 hours after starting monophasic pulsed microcurrent stimulation. Polarization of integrin α2β1 and lamellipodia formation were detected by immunofluorescent staining 10 minutes after starting monophasic pulsed microcurrent stimulation. The migration toward the cathode was significantly higher in the cells treated with the 200-μA monophasic pulsed microcurrent than in the controls (P microcurrent did not alter the migration ratio. The electrostimulus of 200 μA also promoted integrin α2β1 polarization and lamellipodia formation at the cathode edge (P microcurrent intensity to promote migration toward the cathode, and this intensity could regulate polarization of migration-related intracellular factors in human dermal fibroblasts.

  8. Fluctuation-dissipation theorem for frequency-dependent specific heat

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Nielsen, Johannes K.

    1996-01-01

    A derivation of the fluctuation-dissipation (FD) theorem for the frequency-dependent specific heat of a system described by a master equation is presented. The FD theorem is illustrated by a number of simple examples, including a system described by a linear Langevin equation, a two-level system......, and a system described by the energy master equation. It is shown that for two quite different models with low-energy cutoffs—a collection of two-level systems and a system described by the energy master equation—the frequency-dependent specific heat in dimensionless units becomes universal at low temperatures......, i.e., independent of both energy distribution and temperature. These two models give almost the same universal frequency-dependent specific heat, which compares favorably to experiments on supercooled alcohols....

  9. Frequency-specific attentional modulation in human primary auditory cortex and midbrain.

    Science.gov (United States)

    Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Poser, Benedikt A; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

    2018-07-01

    Paying selective attention to an audio frequency selectively enhances activity within primary auditory cortex (PAC) at the tonotopic site (frequency channel) representing that frequency. Animal PAC neurons achieve this 'frequency-specific attentional spotlight' by adapting their frequency tuning, yet comparable evidence in humans is scarce. Moreover, whether the spotlight operates in human midbrain is unknown. To address these issues, we studied the spectral tuning of frequency channels in human PAC and inferior colliculus (IC), using 7-T functional magnetic resonance imaging (FMRI) and frequency mapping, while participants focused on different frequency-specific sounds. We found that shifts in frequency-specific attention alter the response gain, but not tuning profile, of PAC frequency channels. The gain modulation was strongest in low-frequency channels and varied near-monotonically across the tonotopic axis, giving rise to the attentional spotlight. We observed less prominent, non-tonotopic spatial patterns of attentional modulation in IC. These results indicate that the frequency-specific attentional spotlight in human PAC as measured with FMRI arises primarily from tonotopic gain modulation, rather than adapted frequency tuning. Moreover, frequency-specific attentional modulation of afferent sound processing in human IC seems to be considerably weaker, suggesting that the spotlight diminishes toward this lower-order processing stage. Our study sheds light on how the human auditory pathway adapts to the different demands of selective hearing. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Monophasic Pulsed 200-?A Current Promotes Galvanotaxis With Polarization of Actin Filament and Integrin ?2?1 in Human Dermal Fibroblasts

    OpenAIRE

    Uemura, Mikiko; Maeshige, Noriaki; Koga, Yuka; Ishikawa-Aoyama, Michiko; Miyoshi, Makoto; Sugimoto, Masaharu; Terashi, Hiroto; Usami, Makoto

    2016-01-01

    Objective: The monophasic pulsed microcurrent is used to promote wound healing, and galvanotaxis regulation has been reported as one of the active mechanisms in the promotion of tissue repair with monophasic pulsed microcurrent. However, the optimum monophasic pulsed microcurrent parameters and intracellular changes caused by the monophasic pulsed microcurrent have not been elucidated in human dermal fibroblasts. The purpose of this study was to investigate the optimum intensity for promoting...

  11. Low frequency steady-state brain responses modulate large scale functional networks in a frequency-specific means.

    Science.gov (United States)

    Wang, Yi-Feng; Long, Zhiliang; Cui, Qian; Liu, Feng; Jing, Xiu-Juan; Chen, Heng; Guo, Xiao-Nan; Yan, Jin H; Chen, Hua-Fu

    2016-01-01

    Neural oscillations are essential for brain functions. Research has suggested that the frequency of neural oscillations is lower for more integrative and remote communications. In this vein, some resting-state studies have suggested that large scale networks function in the very low frequency range (frequency characteristics of brain networks because both resting-state studies and conventional frequency tagging approaches cannot simultaneously capture multiple large scale networks in controllable cognitive activities. In this preliminary study, we aimed to examine whether large scale networks can be modulated by task-induced low frequency steady-state brain responses (lfSSBRs) in a frequency-specific pattern. In a revised attention network test, the lfSSBRs were evoked in the triple network system and sensory-motor system, indicating that large scale networks can be modulated in a frequency tagging way. Furthermore, the inter- and intranetwork synchronizations as well as coherence were increased at the fundamental frequency and the first harmonic rather than at other frequency bands, indicating a frequency-specific modulation of information communication. However, there was no difference among attention conditions, indicating that lfSSBRs modulate the general attention state much stronger than distinguishing attention conditions. This study provides insights into the advantage and mechanism of lfSSBRs. More importantly, it paves a new way to investigate frequency-specific large scale brain activities. © 2015 Wiley Periodicals, Inc.

  12. Frequency-specific attentional modulation in human primary auditory cortex and midbrain

    NARCIS (Netherlands)

    Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Poser, Benedikt A; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

    2018-01-01

    Paying selective attention to an audio frequency selectively enhances activity within primary auditory cortex (PAC) at the tonotopic site (frequency channel) representing that frequency. Animal PAC neurons achieve this 'frequency-specific attentional spotlight' by adapting their frequency tuning,

  13. Frequency-specific insight into short-term memory capacity

    OpenAIRE

    Feurra, Matteo; Galli, Giulia; Pavone, Enea Francesco; Rossi, Alessandro; Rossi, Simone

    2016-01-01

    We provided novel evidence of a frequency-specific effect by transcranial alternating current stimulation (tACS) of the left posterior parietal cortex on short-term memory, during a digit span task. the effect was prominent with stimulation at beta frequency for young and not for middle-aged adults and correlated with age. Our findings highlighted a short-term memory capacity improvement by tACS application.

  14. Enhancement of delay eyelid conditioning by microcurrent electrical stimulation of the medial prefrontal cortex is triggered by the expression of Fos protein in guinea pigs.

    Science.gov (United States)

    Zheng, Ya-Juan; Dong, Yu-Chen; Zhu, Chao; Zhao, Mei-Sheng

    2016-03-01

    Eyelid conditioning, including delay eyelid conditioning and trace eyelid conditioning, has been used extensively to study neural structures and mechanisms of learning and memory as a form of associative learning. In the present study, microcurrent electrical stimulation was used to stimulate the medial prefrontal cortex (mPFC) to induce delay eyelid conditioning in guinea pigs. The acquisition rate and relative latency of the conditioned eyelid response (CR) and the startle eyelid response (SR) were analyzed. The mPFC sites in the guinea pigs were examined under a light microscope following Nissl staining. In addition, the expression of Fos protein in neurons was detected using immunohistochemistry and western blot analysis. The results indicated that the acquisition rates of CR and SR were increased significantly (Pmicrocurrent electrical stimulation of the mPFC in guinea pigs was triggered by the expression of Fos protein. The observations of the present study further expand the understanding of conditioned reflexes and may aid future investigations into the formation of eyelid conditioning and the mechanisms underlying the circuit in various conditions.

  15. Frequency-Specific Alternations in the Amplitude of Low-Frequency Fluctuations in Chronic Tinnitus

    Directory of Open Access Journals (Sweden)

    Yu-Chen eChen

    2015-10-01

    Full Text Available Tinnitus, a phantom ringing, buzzing or hissing sensation with potentially debilitating consequences, is thought to arise from aberrant spontaneous neural activity at one or more sites within the central nervous system; however, the location and specific features of these oscillations are poorly understood with respect to specific tinnitus features. Recent resting-state functional magnetic resonance imaging (fMRI studies suggest that aberrant fluctuations in spontaneous low-frequency oscillations (LFO of the blood oxygen level-dependent (BOLD signal may be an important factor in chronic tinnitus; however, the role that frequency-specific components of LFO play in subjective tinnitus remains unclear. A total of 39 chronic tinnitus patients and 41 well-matched healthy controls participated in the resting-state fMRI scans. The LFO amplitudes were investigated using the amplitude of low-frequency fluctuation (ALFF and fractional ALFF (fALFF in two different frequency bands (slow-4: 0.027-0.073 Hz and slow-5: 0.01-0.027 Hz. We observed significant differences between tinnitus patients and normal controls in ALFF/fALFF in the two bands (slow-4 and slow-5 in several brain regions including the superior frontal gyrus (SFG, inferior frontal gyrus, middle temporal gyrus, angular gyrus, supramarginal gyrus, and middle occipital gyrus. Across the entire subject pool, significant differences in ALFF/fALFF between the two bands were found in the midbrain, basal ganglia, hippocampus and cerebellum (Slow 4>Slow 5, and in the middle frontal gyrus, supramarginal gyrus, posterior cingulate cortex, and precuneus (Slow 5>Slow 4. We also observed significant interaction between frequency bands and patient groups in the orbitofrontal gyrus. Furthermore, tinnitus distress was positively correlated with the magnitude of ALFF in right SFG and the magnitude of fALFF slow-4 band in left SFG, whereas tinnitus duration was positively correlated with the magnitude of ALFF in

  16. Frequency-specific corticofugal modulation of the dorsal cochlear nucleus in mice.

    Science.gov (United States)

    Kong, Lingzhi; Xiong, Colin; Li, Liang; Yan, Jun

    2014-01-01

    The primary auditory cortex (AI) modulates the sound information processing in the lemniscal subcortical nuclei, including the anteroventral cochlear nucleus (AVCN), in a frequency-specific manner. The dorsal cochlear nucleus (DCN) is a non-lemniscal subcortical nucleus but it is tonotopically organized like the AVCN. However, it remains unclear how the AI modulates the sound information processing in the DCN. This study examined the impact of focal electrical stimulation of AI on the auditory responses of the DCN neurons in mice. We found that the electrical stimulation induced significant changes in the best frequency (BF) of DCN neurons. The changes in the BFs were highly specific to the BF differences between the stimulated AI neurons and the recorded DCN neurons. The DCN BFs shifted higher when the AI BFs were higher than the DCN BFs and the DCN BFs shifted lower when the AI BFs were lower than the DCN BFs. The DCN BFs showed no change when the AI and DCN BFs were similar. Moreover, the BF shifts were linearly correlated to the BF differences. Thus, our data suggest that corticofugal modulation of the DCN is also highly specific to frequency information, similar to the corticofugal modulation of the AVCN. The frequency-specificity of corticofugal modulation does not appear limited to the lemniscal ascending pathway.

  17. Specificity of the Human Frequency Following Response for Carrier and Modulation Frequency Assessed Using Adaptation.

    Science.gov (United States)

    Gockel, Hedwig E; Krugliak, Alexandra; Plack, Christopher J; Carlyon, Robert P

    2015-12-01

    The frequency following response (FFR) is a scalp-recorded measure of phase-locked brainstem activity to stimulus-related periodicities. Three experiments investigated the specificity of the FFR for carrier and modulation frequency using adaptation. FFR waveforms evoked by alternating-polarity stimuli were averaged for each polarity and added, to enhance envelope, or subtracted, to enhance temporal fine structure information. The first experiment investigated peristimulus adaptation of the FFR for pure and complex tones as a function of stimulus frequency and fundamental frequency (F0). It showed more adaptation of the FFR in response to sounds with higher frequencies or F0s than to sounds with lower frequency or F0s. The second experiment investigated tuning to modulation rate in the FFR. The FFR to a complex tone with a modulation rate of 213 Hz was not reduced more by an adaptor that had the same modulation rate than by an adaptor with a different modulation rate (90 or 504 Hz), thus providing no evidence that the FFR originates mainly from neurons that respond selectively to the modulation rate of the stimulus. The third experiment investigated tuning to audio frequency in the FFR using pure tones. An adaptor that had the same frequency as the target (213 or 504 Hz) did not generally reduce the FFR to the target more than an adaptor that differed in frequency (by 1.24 octaves). Thus, there was no evidence that the FFR originated mainly from neurons tuned to the frequency of the target. Instead, the results are consistent with the suggestion that the FFR for low-frequency pure tones at medium to high levels mainly originates from neurons tuned to higher frequencies. Implications for the use and interpretation of the FFR are discussed.

  18. MULTILOOP PI CONTROLLER FOR ACHIEVING SIMULTANEOUS TIME AND FREQUENCY DOMAIN SPECIFICATIONS

    Directory of Open Access Journals (Sweden)

    M. SENTHILKUMAR

    2015-08-01

    Full Text Available Most of the controllers in control system are designed to satisfy either time domain or frequency domain specifications. This work presents the computation of a multiloop PI controller for achieving time and frequency domain specifications simultaneously. The desired time and frequency domain measures are to be specified initially to the design. To obtain the desired value of the performance measures the graphical relationship between the PI controller and the performance criteria is given. Thus by using graphical method a set of PI controller parameters to meet the desired performance measures are obtained in an effective and simpler way. The coupled tank has become a classic design of control engineering for multivariable process. The proposed control strategy has been implemented in the same coupled tank process and validated through simulation studies.

  19. Low frequency vibrations induce malformations in two aquatic species in a frequency-, waveform-, and direction-specific manner.

    Directory of Open Access Journals (Sweden)

    Laura N Vandenberg

    Full Text Available Environmental toxicants such as industrial wastes, air particulates from machinery and transportation vehicles, and pesticide run-offs, as well as many chemicals, have been widely studied for their effects on human and wildlife populations. Yet other potentially harmful environmental pollutants such as electromagnetic pulses, noise and vibrations have remained incompletely understood. Because developing embryos undergo complex morphological changes that can be affected detrimentally by alterations in physical forces, they may be particularly susceptible to exposure to these types of pollutants. We investigated the effects of low frequency vibrations on early embryonic development of two aquatic species, Xenopus laevis (frogs and Danio rerio (zebrafish, specifically focusing on the effects of varying frequencies, waveforms, and applied direction. We observed treatment-specific effects on the incidence of neural tube defects, left-right patterning defects and abnormal tail morphogenesis in Xenopus tadpoles. Additionally, we found that low frequency vibrations altered left-right patterning and tail morphogenesis, but did not induce neural tube defects, in zebrafish. The results of this study support the conclusion that low frequency vibrations are toxic to aquatic vertebrates, with detrimental effects observed in two important model species with very different embryonic architectures.

  20. Individual differences and specificity of prefrontal gamma frequency-tACS on fluid intelligence capabilities.

    Science.gov (United States)

    Santarnecchi, E; Muller, T; Rossi, S; Sarkar, A; Polizzotto, N R; Rossi, A; Cohen Kadosh, R

    2016-02-01

    Emerging evidence suggests that transcranial alternating current stimulation (tACS) is an effective, frequency-specific modulator of endogenous brain oscillations, with the potential to alter cognitive performance. Here, we show that reduction in response latencies to solve complex logic problem indexing fluid intelligence is obtained through 40 Hz-tACS (gamma band) applied to the prefrontal cortex. This improvement in human performance depends on individual ability, with slower performers at baseline receiving greater benefits. The effect could have not being explained by regression to the mean, and showed task and frequency specificity: it was not observed for trials not involving logical reasoning, as well as with the application of low frequency 5 Hz-tACS (theta band) or non-periodic high frequency random noise stimulation (101-640 Hz). Moreover, performance in a spatial working memory task was not affected by brain stimulation, excluding possible effects on fluid intelligence enhancement through an increase in memory performance. We suggest that such high-level cognitive functions are dissociable by frequency-specific neuromodulatory effects, possibly related to entrainment of specific brain rhythms. We conclude that individual differences in cognitive abilities, due to acquired or developmental origins, could be reduced during frequency-specific tACS, a finding that should be taken into account for future individual cognitive rehabilitation studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. A class frequency mixture model that adjusts for site-specific amino acid frequencies and improves inference of protein phylogeny

    Directory of Open Access Journals (Sweden)

    Li Karen

    2008-12-01

    Full Text Available Abstract Background Widely used substitution models for proteins, such as the Jones-Taylor-Thornton (JTT or Whelan and Goldman (WAG models, are based on empirical amino acid interchange matrices estimated from databases of protein alignments that incorporate the average amino acid frequencies of the data set under examination (e.g JTT + F. Variation in the evolutionary process between sites is typically modelled by a rates-across-sites distribution such as the gamma (Γ distribution. However, sites in proteins also vary in the kinds of amino acid interchanges that are favoured, a feature that is ignored by standard empirical substitution matrices. Here we examine the degree to which the pattern of evolution at sites differs from that expected based on empirical amino acid substitution models and evaluate the impact of these deviations on phylogenetic estimation. Results We analyzed 21 large protein alignments with two statistical tests designed to detect deviation of site-specific amino acid distributions from data simulated under the standard empirical substitution model: JTT+ F + Γ. We found that the number of states at a given site is, on average, smaller and the frequencies of these states are less uniform than expected based on a JTT + F + Γ substitution model. With a four-taxon example, we show that phylogenetic estimation under the JTT + F + Γ model is seriously biased by a long-branch attraction artefact if the data are simulated under a model utilizing the observed site-specific amino acid frequencies from an alignment. Principal components analyses indicate the existence of at least four major site-specific frequency classes in these 21 protein alignments. Using a mixture model with these four separate classes of site-specific state frequencies plus a fifth class of global frequencies (the JTT + cF + Γ model, significant improvements in model fit for real data sets can be achieved. This simple mixture model also reduces the long

  2. Microcurrent application as analgesic treatment in venous ulcers: a pilot study La aplicación de microcorriente como tratamiento en las úlceras venosas: un estudio piloto Aplicação da microcorrente como recurso para tratamento de úlceras venosas: um estudo piloto

    Directory of Open Access Journals (Sweden)

    Raciele Ivandra Guarda Korelo

    2012-08-01

    Full Text Available This study aimed to evaluate the effect of microcurrent electrical stimulation on pain and area of venous ulcers. In a pilot study for a single-blind controlled clinical trial, carried out at an outpatient clinic during four weeks, 14 subjects with venous ulcers (mean age 62±9 years were divided in two groups: microcurrent (n=8 and control group (n=6. Pain (by Visual Analogue Scale and the ulcer area were measured by planimetry. There was a significant difference between the two groups with respect to pain (microcurrent group from 8.5 (6.5-9.75 to 3.5 (1-4.75 and control group from 7.5 (5.75-10 to 8.5 (5.5-10, pEste estudio objetivó evaluar el efecto de la estimulación eléctrica por microcorriente sobre el dolor y el área de superficie de úlceras venosas. En un estudio piloto para un ensayo clínico controlado simple ciego, realizado en una clínica durante 4 semanas, se dividieron 14 individuos (62±9 años de edad en dos grupos: grupo microcorriente (n=8 y grupo control (n=6. Se evaluaron el dolor (por medio de la Escala Visual Analógica y el área de superficie de la úlcera por medio de la Planimetría. Hubo diferencia significativa entre los dos grupos con relación al dolor (grupo de microcorriente de 8,5 (6,5-9,75 para 3,5 (1-4,75 y grupo control de 7,5 (5,75-10 para 8,5 (5,5-10, pO objetivo neste estudo foi avaliar o efeito da estimulação elétrica, por microcorrente, sobre a dor e a área de superfície de úlceras venosas. Em estudo-piloto para um ensaio clínico controlado simples-cego, realizado em uma clínica durante 4 semanas, dividiram-se 14 indivíduos (62±9 anos de idade em dois grupos: grupo microcorrente (n=8 e grupo-controle (n=6. Avaliaram-se a dor (por meio da Escala Visual Analógica e a área de superfície da úlcera por meio da Planimetria. Houve diferença significativa entre os dois grupos em relação à dor (grupo de microcorrente de 8,5 (6,5-9,75 para 3,5 (1-4,75 e grupo-controle de 7,5 (5,75-10 para 8

  3. Frequency-specific insight into short-term memory capacity.

    Science.gov (United States)

    Feurra, Matteo; Galli, Giulia; Pavone, Enea Francesco; Rossi, Alessandro; Rossi, Simone

    2016-07-01

    The digit span is one of the most widely used memory tests in clinical and experimental neuropsychology for reliably measuring short-term memory capacity. In the forward version, sequences of digits of increasing length have to be reproduced in the order in which they are presented, whereas in the backward version items must be reproduced in the reversed order. Here, we assessed whether transcranial alternating current stimulation (tACS) increases the memory span for digits of young and midlife adults. Imperceptibly weak electrical currents in the alpha (10 Hz), beta (20 Hz), theta (5 Hz), and gamma (40 Hz) range, as well as a sham stimulation, were delivered over the left posterior parietal cortex, a cortical region thought to sustain maintenance processes in short-term memory through oscillatory brain activity in the beta range. We showed a frequency-specific effect of beta-tACS that robustly increased the forward memory span of young, but not middle-aged, healthy individuals. The effect correlated with age: the younger the subjects, the greater the benefit arising from parietal beta stimulation. Our results provide evidence of a short-term memory capacity improvement in young adults by online frequency-specific tACS application. Copyright © 2016 the American Physiological Society.

  4. Stimulation of Protein Expression Through the Harmonic Resonance of Frequency-Specific Music.

    Science.gov (United States)

    Orhan, Ibrahim Y; Gulbahar, Burak A

    2016-12-01

    The use of specific frequencies for specific individual amino acids may increase the potential energy of protein molecules in the medium [1]. The resonance would also increase the movement of particles in the cytosol, increasing the collisions necessary for the conduction of protein expression. The clash of two waves that share frequencies will exhibit an increase in energy through an increase in amplitude [2]. The increase in energy would in turn increase the number of collisions forming the tRNA-amino acid, increasing the amino acid acquiry for ribosomes to improve intracellular efficiency in gene expression. To test the hypothesis, Red Fluorescent Protein (RFP) in transformated BL-21 strains of E. coli and p53 protein of MCF-7 were examined after exposure to sounds of specific frequencies. Through the exposure of the experimental systems to a sequence of sounds that match the frequencies of specific amino acids, the levels of RFP exhibition respective to the control groups in the bacterial medium increased two-fold in terms of RFU. The experiments that targeted the p53 protein with the 'music' showed a decrease in the cell prevalence in the MCF-7 type breast cancer cells by 28%, by decreasing the speed of tumour formation. Exposure to 'music' that was designed through assigning a musical note for every single one of the twenty unique amino acids, produced both an analytical and a visible shift in protein synthesis, making it as potential tool for reducing procedural time uptake.

  5. Frequency-specific masking effect by vibrotactile stimulation to the forearm

    NARCIS (Netherlands)

    Tanaka, Y.; Matsuoka, S.; Bergmann Tiest, W.M.; Kappers, A.M.L.; Minamizawa, K.; Sano, A.; Bello, F.; Kajimoto, H.; Visell, Y.

    2016-01-01

    This paper demonstrates frequency-specific masking of tactile sensations on the index finger by remote vibrotactile stimulation. A vibration of 50 Hz was presented to the index finger. In three experimental conditions, the detection threshold for this vibration was determined with a masking

  6. Sharing specific "We" autobiographical memories in close relationships: the role of contact frequency.

    Science.gov (United States)

    Beike, Denise R; Cole, Holly E; Merrick, Carmen R

    2017-11-01

    Sharing memories in conversations with close others is posited to be part of the social function of autobiographical memory. The present research focused on the sharing of a particular type of memory: Specific memories about one-time co-experienced events, which we termed Specific We memories. Two studies with 595 total participants examined the factors that lead to and/or are influenced by the sharing of Specific We memories. In Study 1, participants reported on their most recent conversation. Specific We memories were reportedly discussed most often in conversations with others who were close and with whom the participant had frequent communication. In Study 2, participants were randomly assigned either to increase or to simply record the frequency of communication with a close other (parent). Increases in the frequency of reported sharing of Specific We memories as well as closeness to the parent resulted. Mediation analyses of both studies revealed causal relationships among reported sharing of Specific We memories and closeness. We discuss the relevance of these results for understanding the social function of autobiographical memory.

  7. Neurofeedback of SMR and Beta1 Frequencies: An Investigation of Learning Indices and Frequency-Specific Effects.

    Science.gov (United States)

    Pimenta, Miguel G; van Run, Chris; de Fockert, Jan W; Gruzelier, John H

    2018-05-15

    Despite evidence that Sensorimotor Rhythm (SMR) and beta1 neurofeedback have distinct cognitive enhancement effects, it remains unclear whether their amplitudes can be independently enhanced. Furthermore, demands for top-down attention control, postural restraint and maintenance of cognitive set processes, all requiring low-beta frequencies, might masquerade as learning and confound interpretation. The feasibility of selectively enhancing SMR and beta1 amplitudes was investigated with the addition of a random frequency control condition that also requires the potentially confounding cognitive processes. A comprehensive approach to assessing neurofeedback learning was undertaken through the calculation of learning indices within- and across-session and pre-to-post baseline. Herein we provide the first demonstration of beta1 within-session amplitude learning that was not attributable to extraneous cognitive processes, for it was not found with random frequency training. On the other hand, within-session SMR learning might have been obscured by high interindividual variability and methodological limitations such as the type of feedback screen, the insufficient number of sessions, and the exclusion of simultaneous theta and high-beta inhibition. Interestingly, SMR and beta1 amplitude increased across sessions in the three groups suggesting unspecific effects of neurofeedback in the low beta frequency band. Moreover, there was no clear evidence of frequency specificity associated with either SMR or beta1 training. Some methodological limitations may underpin the divergent results with previous studies. Copyright © 2017 IBRO. All rights reserved.

  8. Frequency and specificity of red blood cell alloimmunization in chilean transfused patients.

    Science.gov (United States)

    Caamaño, José; Musante, Evangelina; Contreras, Margarita; Ulloa, Hernán; Reyes, Carolina; Inaipil, Verónica; Saavedra, Nicolás; Guzmán, Neftalí

    2015-01-01

    Alloimmunization is an adverse effect of blood transfusions. In Chile, alloimmunization frequency is not established, and for this reason the aim of this study was to investigate the prevalence and specificity of red blood cell (RBC) alloantibodies in Chilean transfused subjects. Records from 4,716 multi-transfused patients were analyzed. In these patients, antibody screening was carried out prior to cross-matching with a commercially available two-cell panel by the microcolum gel test, and samples with a positive screen were analyzed for the specificity of the alloantibody with a 16-cell identification panel. The incidence of RBC alloimmunization in transfused patients was 1.02% (48/4,716) with a higher prevalence in women (40/48). We detected 52 antibodies, the most frequent specificities identified were anti-E (30.8%), anti-K (26.9%), anti-D (7.7%), and anti-Fy(a) (5.8%). The highest incidence of alloantibodies was observed in cancer and gastroenterology patients. The data demonstrated a low alloimmunization frequency in Chilean transfused patients, principally associated with antibodies anti-E, anti-K, anti-D, and anti-Fy(a).

  9. Frequency specific modulation of human somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Matteo eFeurra

    2011-02-01

    Full Text Available Oscillatory neuronal activities are commonly observed in response to sensory stimulation. However, their functional roles are still the subject of debate. One way to probe the roles of oscillatory neural activities is to deliver alternating current to the cortex at biologically relevant frequencies and examine whether such stimulation influences perception and cognition. In this study, we tested whether transcranial alternating current stimulation (tACS over the primary somatosensory cortex (SI could elicit tactile sensations in humans in a frequency dependent manner. We tested the effectiveness of tACS over SI at frequency bands ranging from 2 to 70 Hz. Our results show that stimulation in alpha (10-14 Hz and high gamma (52-70 Hz frequency range produces a tactile sensation in the contralateral hand. A weaker effect was also observed for beta (16-20 Hz stimulation. These findings highlight the frequency-dependency of effective tACS over SI with the effective frequencies corresponding to those observed in previous EEG/MEG studies of tactile perception. Our present study suggests that tACS could be used as a powerful online stimulation technique to reveal the causal roles of oscillatory brain activities.

  10. Impact of introducing specific measures to reduce the frequency of cesarean delivery for non-obstetric indications.

    Science.gov (United States)

    Psenkova, Petra; Bucko, Marek; Braticak, Michal; Baneszova, Ruth; Zahumensky, Jozef

    2018-03-25

    To identify the frequency of cesarean delivery for non-obstetric indications before and after the introduction of specific measures to lower the rate of elective cesarean, and to evaluate the effectiveness of the introduced measures. In the present single-center retrospective cohort study at University Hospital Trnava, Trnava, Slovak Republic, the frequency of elective cesarean was evaluated before (January 1, 2010, to December 31, 2014) and after (January 1, 2015, to December 31, 2016) the implementation of specific measures applied in January 2015 to confirm the indications for primary cesarean delivery. The frequency of elective cesarean delivery for non-obstetric indications was compared between the two periods. Before the intervention in 2015, 229 (2.9%) of 7768 women had elective cesarean deliveries for non-obstetric indications. After implementation of the intervention, the frequency decreased to 27 (0.8%) of 3203 women (Pdelivery for non-obstetric indications was reduced significantly by introducing specific reasonable measures. These included all non-obstetric indications for cesarean delivery being approved by a leading specialist of the related department, close cooperation with professionals from other specialties, and, additionally, staff attending professional educational lectures. © 2018 International Federation of Gynecology and Obstetrics.

  11. Beyond Phonotactic Frequency: Presentation Frequency Effects Word Productions in Specific Language Impairment

    Science.gov (United States)

    Plante, Elena; Bahl, Megha; Vance, Rebecca; Gerken, LouAnn

    2011-01-01

    Phonotactic frequency effects on word production are thought to reflect accumulated experience with a language. Here we demonstrate that frequency effects can also be obtained through short-term manipulations of the input to children. We presented children with nonwords in an experiment that systematically manipulated English phonotactic frequency…

  12. Layer-specific high-frequency spiking in the prefrontal cortex of awake rats

    Directory of Open Access Journals (Sweden)

    Zimbo Saroeni Raymond Maria Boudewijns

    2013-06-01

    Full Text Available Cortical pyramidal neurons show irregular in vivo action potential (AP spiking with high frequency bursts occurring on sparse background activity. Somatic APs can backpropagate from soma into basal and apical dendrites and locally generate dendritic calcium spikes. The critical AP frequency for generation of such dendritic calcium spikes can be very different depending on cell-type or brain area involved. Previously, it was shown in vitro that calcium electrogenesis can also be induced in L(ayer 5 pyramidal neurons of prefrontal cortex (PFC. It remains an open question whether somatic burst spiking and resulting dendritic calcium electrogenesis also occur in morphologically more compact L2/3 pyramidal neurons. Furthermore, it is not known whether critical frequencies that trigger dendritic calcium electrogenesis occur in PFC under awake conditions in vivo. Here, we addressed these issues and found that pyramidal neurons in both PFC L2/3 and L5 in awake rats spike APs in short bursts, but with different probabilities. The critical frequency for calcium electrogenesis in vitro was layer-specific and lower in L5 neurons compared to L2/3. Taking the in vitro critical frequency as predictive measure for dendritic electrogenesis during in vivo spontaneous activity, supracritical bursts in vivo were observed in a larger fraction of L5 neurons compared to L2/3 neurons but with similar incidence within these subpopulations. Together, these results show that in PFC of awake rats, AP spiking occurs at frequencies that are relevant for dendritic calcium electrogenesis and suggest that in awake rat PFC, dendritic calcium electrogenesis may be involved in neuronal computation.

  13. Frequency specificity and left-ear advantage of medial olivocochlear efferent modulation: a study based on stimulus frequency otoacoustic emission.

    Science.gov (United States)

    Xing, Dongjia; Gong, Qin

    2017-09-06

    The medial olivocochlear (MOC) bundle is an auditory nucleus that projects efferent nerve fibers to the outer hair cells (OHCs) for synaptic innervation. The aim of the present study was to investigate the possible existence of frequency and ear specificity in MOC efferent modulation, as well as how MOC activation influences cochlear tuning. Stimulus frequency otoacoustic emissions (SFOAEs) were used to study MOC efferent modulation. Therefore, the current experiment was designed to compare the degree of SFOAE suppression in the both ears of 20 individuals at 1, 2, 4, and 8 kHz. We also compared changes in Q10 values of SFOAE suppression tuning curves at 1, 2, and 4 kHz under contralateral acoustic stimulation (CAS) and no-CAS conditions. We observed a significant reduction in SFOAE magnitude in the CAS condition compared with the no-CAS condition at 1 and 2 kHz in the left ear. A significant difference in CAS suppression was also found between the left and right ears at 1 and 2 kHz, with larger CAS suppression in the left ear. CAS further produced a statistically significant increase in the Q10 value at 1 kHz and a significant reduction in Q10 values at 2 and 4 kHz. These findings suggest a left-ear advantage in terms of CAS-induced MOC efferent SFOAE suppression, with larger MOC efferent modulation for lower frequencies, and cochlear tuning was sharpened by means of MOC activation at lower frequencies and broadened at higher frequencies.

  14. What Determines the Speed of Lexical Access: Homophone or Specific-Word Frequency? A Reply to Jescheniak et al. (2003)

    Science.gov (United States)

    Caramazza, Alfonso; Bi, Yanchao; Costa, Albert; Miozzo, Michelle

    2004-01-01

    A. Caramazza, A. Costa, M. Miozzo, and Y. Bi (2001) reported a series of experiments showing that naming latencies for homophones are determined by specific-word frequency (e.g., frequency of nun) and not homophone frequency (frequency of nun + none). J. D. Jescheniak, A. S. Meyer, and W. J. M. Levelt (2003) have challenged these studies on a…

  15. Frequency Specific Effects of ApoE ε4 Allele on Resting-State Networks in Nondemented Elders

    Directory of Open Access Journals (Sweden)

    Ying Liang

    2017-01-01

    Full Text Available We applied resting-state functional magnetic resonance imaging (fMRI to examine the Apolipoprotein E (ApoE ε4 allele effects on functional connectivity of the default mode network (DMN and the salience network (SN. Considering the frequency specific effects of functional connectivity, we decomposed the brain network time courses into two bands: 0.01–0.027 Hz and 0.027–0.08 Hz. All scans were acquired by the Alzheimer’s Disease Neuroscience Initiative (ADNI. Thirty-two nondemented subjects were divided into two groups based on the presence (n=16 or absence (n=16 of the ApoE ε4 allele. We explored the frequency specific effects of ApoE ε4 allele on the default mode network (DMN and the salience network (SN functional connectivity. Compared to ε4 noncarriers, the DMN functional connectivity of ε4 carriers was significantly decreased while the SN functional connectivity of ε4 carriers was significantly increased. Many functional connectivities showed significant differences at the lower frequency band of 0.01–0.027 Hz or the higher frequency band of 0.027–0.08 Hz instead of the typical range of 0.01–0.08 Hz. The results indicated a frequency dependent effect of resting-state signals when investigating RSNs functional connectivity.

  16. Improved imputation accuracy of rare and low-frequency variants using population-specific high-coverage WGS-based imputation reference panel.

    Science.gov (United States)

    Mitt, Mario; Kals, Mart; Pärn, Kalle; Gabriel, Stacey B; Lander, Eric S; Palotie, Aarno; Ripatti, Samuli; Morris, Andrew P; Metspalu, Andres; Esko, Tõnu; Mägi, Reedik; Palta, Priit

    2017-06-01

    Genetic imputation is a cost-efficient way to improve the power and resolution of genome-wide association (GWA) studies. Current publicly accessible imputation reference panels accurately predict genotypes for common variants with minor allele frequency (MAF)≥5% and low-frequency variants (0.5≤MAF<5%) across diverse populations, but the imputation of rare variation (MAF<0.5%) is still rather limited. In the current study, we evaluate imputation accuracy achieved with reference panels from diverse populations with a population-specific high-coverage (30 ×) whole-genome sequencing (WGS) based reference panel, comprising of 2244 Estonian individuals (0.25% of adult Estonians). Although the Estonian-specific panel contains fewer haplotypes and variants, the imputation confidence and accuracy of imputed low-frequency and rare variants was significantly higher. The results indicate the utility of population-specific reference panels for human genetic studies.

  17. An analysis of boundary-effects in obtaining the frequency dependent specific heat by effusivity measurements

    DEFF Research Database (Denmark)

    Christensen, Tage Emil; Behrens, Claus

    The frequency dependent specific heat is a significant response function characterizing the glass transition. Contrary to the dielectric response it is not easily measured over many decades. The introduction of the 3-omega method, where the temperature oscillations at a planar oscillatoric heat g...

  18. The effect of uncertainties in nuclear reactor plant-specific failure data on core damage frequency

    International Nuclear Information System (INIS)

    Martz, H.F.

    1995-05-01

    It is sometimes the case in PRA applications that reported plant-specific failure data are, in fact, only estimates which are uncertain. Even for detailed plant-specific data, the reported exposure time or number of demands is often only an estimate of the actual exposure time or number of demands. Likewise the reported number of failure events or incidents is sometimes also uncertain because incident or malfunction reports may be ambiguous. In this report we determine the corresponding uncertainty in core damage frequency which can b attributed to such uncertainties in plant-specific data using a simple but typical nuclear power reactor example

  19. Continuous High Frequency Activity: A peculiar SEEG pattern related to specific brain regions

    Science.gov (United States)

    Melani, Federico; Zelmann, Rina; Mari, Francesco; Gotman, Jean

    2015-01-01

    Objective While visually marking the high frequency oscillations in the stereo-EEG of epileptic patients, we observed a continuous/semicontinuous activity in the ripple band (80–250 Hz), which we defined continuous High Frequency Activity (HFA). We aim to analyze in all brain regions the occurrence and significance of this particular pattern. Methods Twenty patients implanted in mesial temporal and neocortical areas were studied. One minute of slow-wave sleep was reviewed. The background was classified as continuous/semicontinuous, irregular, or sporadic based on the duration of the fast oscillations. Each channel was classified as inside/outside the seizure onset zone (SOZ) or a lesion. Results The continuous/semicontinuous HFA occurred in 54 of the 790 channels analyzed, with a clearly higher prevalence in hippocampus and occipital lobe. No correlation was found with the SOZ or lesions. In the occipital lobe the continuous/semicontinuous HFA was present independently of whether eyes were open or closed. Conclusions We describe what appears to be a new physiological High Frequency Activity, independent of epileptogenicity, present almost exclusively in the hippocampus and occipital cortex but independent of the alpha rhythm. Significance The continuous HFA may be an intrinsic characteristic of specific brain regions, reflecting a particular type of physiological neuronal activity. PMID:23768436

  20. Frequency specific activity in subthalamic nucleus correlates with hand bradykinesia in Parkinson's disease.

    Science.gov (United States)

    Tan, Huiling; Pogosyan, Alek; Anzak, Anam; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Ashkan, Keyoumars; Bogdanovic, Marko; Green, Alexander L; Aziz, Tipu; Brown, Peter

    2013-02-01

    Local field potential recordings made from the basal ganglia of patients undergoing deep brain stimulation have suggested that frequency specific activity is involved in determining the rate of force development and the peak force at the outset of a movement. However, the extent to which the basal ganglia might be involved in motor performance later on in a sustained contraction is less clear. We therefore recorded from the subthalamic nucleus region (STNr) in patients with Parkinson's disease (PD) as they made maximal voluntary grips. Relative to age-matched controls they had more rapid force decrement when contraction was meant to be sustained and prolonged release reaction time and slower rate of force offset when they were supposed to release the grip. These impairments were independent from medication status. Increased STNr power over 5-12 Hz (in the theta/alpha band) independently predicted better performance-reduced force decrement, shortened release reaction time and faster rate of force offset. In contrast, lower mean levels and progressive reduction of STNr power over 55-375 Hz (high gamma/high frequency) over the period when contraction was meant to be sustained were both strongly associated with greater force decrement over time. Higher power over 13-23 Hz (low beta) was associated with more rapid force decrement during the period when grip should have been sustained, and with a paradoxical shortening of the release reaction time. These observations suggest that STNr activities at 5-12 Hz and 55-375 Hz are necessary for optimal grip performance and that deficiencies of such activities lead to motor impairments. In contrast, increased levels of 13-25 Hz activity both promote force decrement and shorten the release reaction time, consistent with a role in antagonising (and terminating) voluntary movement. Frequency specific oscillatory activities in the STNr impact on motor performance from the beginning to the end of a voluntary grip. Copyright © 2012

  1. The changes of the frequency specific impedance of the human body due to the resonance in the kHz range in cancer diagnostics

    Science.gov (United States)

    Michalak, K. P.; Nawrocka-Bogusz, H.

    2011-12-01

    The frequency-specific absorption of kHz signals has been postulated for different tissues, trace elements, vitamins, toxins, pathogens, allergens etc. for low-power (μV) signals. An increase in the impedance of the human body is observed only up to the given power of the applied signal. The highest amplification of the given signal being damped by the body makes it possible to determine the intensity of the given process in the body (e.g. amount of the toxin, trace element, intensity of the allergy) being connected with a given frequency spectrum of the signal. The mechanism of frequency-specific absorption can be explained by means of the Quantum Field Theory being applied to the structure of the water. Substantially high coincidence between the frequencies of the rotation of free quasi-excited electrons in coherent domains of water and the frequencies being used in the MORA diagnostics (Med-Tronic GmbH, EN ISO 13485, EN ISO 9001) can be observed. These frequencies are located in the proximity of f = 7kHz · i (i = 1,3,5,7,...). This fact suggests that the coherent domains with the admixtures of the given substances create structure-specific coherent domains that possess frequency-specific absorption spectra. The diagnostic tool called "MORA System diagnosis" was used to investigate 102 patients with different types and stages of cancer. Many signals were observed to be absorbed by many cancer patients, e.g.: 'Cellular defense system', 'Degeneration tendencies', Manganese, Magnesium, Zinc, Selenium, Vitamin E, Glutamine, Glutathione, Cysteine, Candida albicans, Mycosis. The results confirm the role of oxidative stress, immunological system deficiency and mitochondria malfunction in the development of cancer.

  2. Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over time

    Directory of Open Access Journals (Sweden)

    Reeves Gillian K

    2011-06-01

    Full Text Available Abstract Background How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large cohort study of middle-aged UK women. Methods At recruitment, Million Women Study participants completed a baseline questionnaire including questions on frequency of strenuous and of any physical activity. About 3 years later 589,896 women also completed a follow-up questionnaire reporting the hours they spent on a range of specific activities. Time spent on each activity was used to estimate the associated excess metabolic equivalent hours (MET-hours and this value was compared across categories of physical activity reported at recruitment. Additionally, 18,655 women completed the baseline questionnaire twice, at intervals of up to 4 years; repeatability over time was assessed using the weighted kappa coefficient (κweighted and absolute percentage agreement. Results The average number of hours per week women reported doing specific activities was 14.0 for housework, 4.5 for walking, 3.0 for gardening, 0.2 for cycling, and 1.4 for all strenuous activity. Time spent and the estimated excess MET-hours associated with each activity increased with increasing frequency of any or strenuous physical activity reported at baseline (tests for trend, P weighted = 0.71 for questionnaires administered less than 6 months apart, and 52% (κweighted = 0.51 for questionnaires more than 2 years apart. Corresponding values for any physical activity were 57% (κweighted = 0.67 and 47% (κweighted = 0.58. Conclusions In this cohort, responses to simple questions on the frequency of any physical activity and of strenuous activity asked at baseline were associated with hours spent on specific activities and the associated estimated excess MET

  3. Nutrition impact symptoms in advanced cancer patients: frequency and specific interventions, a case?control study

    OpenAIRE

    Omlin, Aurelius; Blum, David; Wierecky, Jan; Haile, Sarah R.; Ottery, Faith D.; Strasser, Florian

    2013-01-01

    Background Involuntary weight loss (IWL) is frequent in advanced cancer patients causing compromised anticancer treatment outcomes and function. Cancer cachexia is influenced by nutrition impact symptoms (NIS). The aim of this study was to explore the frequency of NIS in advanced patients and to assess specific interventions guided by a 12-item NIS checklist. Methods Consecutive patients from an outpatient nutrition-fatigue clinic completed the NIS checklist. The NIS checklist was developed b...

  4. On the generation mechanism of ULF seismogenic electromagnetic emissions

    Science.gov (United States)

    Molchanov, O. A.; Hayakawa, M.

    Microfracturing electrification is suggested as a possible mechanism for explaining ULF electromagnetic emissions observed before and after the earthquakes. This effect appears as fast fluctuation of microcracks and leads to the origination of wideband electromagnetic noise. This noise dissipates outside the source region and produces ULF emissions on the ground surface with an upper cutoff frequency ˜1 Hz due to the skin depth attenuation. Each microcurrent results from charge relaxation during microcrack opening and depends on the time of opening and conductivity of the rock medium. The normal size distribution of microcracks, their fast opening and healing (intermittence), and average size progression due to stress corrosion are assumed. Using this model, it is possible to compare these theoretical explanations with the observational results with reference to the intensity, frequency spectrum and temporal development of ULF magnetic field variations.

  5. Establishment of a protein frequency library and its application in the reliable identification of specific protein interaction partners.

    Science.gov (United States)

    Boulon, Séverine; Ahmad, Yasmeen; Trinkle-Mulcahy, Laura; Verheggen, Céline; Cobley, Andy; Gregor, Peter; Bertrand, Edouard; Whitehorn, Mark; Lamond, Angus I

    2010-05-01

    The reliable identification of protein interaction partners and how such interactions change in response to physiological or pathological perturbations is a key goal in most areas of cell biology. Stable isotope labeling with amino acids in cell culture (SILAC)-based mass spectrometry has been shown to provide a powerful strategy for characterizing protein complexes and identifying specific interactions. Here, we show how SILAC can be combined with computational methods drawn from the business intelligence field for multidimensional data analysis to improve the discrimination between specific and nonspecific protein associations and to analyze dynamic protein complexes. A strategy is shown for developing a protein frequency library (PFL) that improves on previous use of static "bead proteomes." The PFL annotates the frequency of detection in co-immunoprecipitation and pulldown experiments for all proteins in the human proteome. It can provide a flexible and objective filter for discriminating between contaminants and specifically bound proteins and can be used to normalize data values and facilitate comparisons between data obtained in separate experiments. The PFL is a dynamic tool that can be filtered for specific experimental parameters to generate a customized library. It will be continuously updated as data from each new experiment are added to the library, thereby progressively enhancing its utility. The application of the PFL to pulldown experiments is especially helpful in identifying either lower abundance or less tightly bound specific components of protein complexes that are otherwise lost among the large, nonspecific background.

  6. EMC Specific Problems of Frequency Converters Used at Interlocking Device

    Directory of Open Access Journals (Sweden)

    J. Novak

    2009-12-01

    Full Text Available The paper deals with problems of electromagnetic compatibility (EMC of frequency control drive of electromotive switch actuator of railway switch. The frequency converter with Pulse Width Modulation (PWM and the output sinus filter are used for feeding of the asynchronous motor of the switch actuator. This drive is operated in an insulated system of feeding voltages. The drive is fed by a frequency converter with an unshielded cable with length up to 1.2 km. The EMC problems occurring at development and operating of the drive are analyzed in this paper. The used solution of these problems and experience with EMC of the given system from real operation are described in this paper as well.

  7. Prospective Study of Alcohol Consumption Quantity and Frequency and Cancer-Specific Mortality in the US Population

    Science.gov (United States)

    Breslow, Rosalind A.; Chen, Chiung M.; Graubard, Barry I.; Mukamal, Kenneth J.

    2011-01-01

    Prospective associations between quantity and frequency of alcohol consumption and cancer-specific mortality were studied using a nationally representative sample with pooled data from the 1988, 1990, 1991, and 1997–2004 administrations of the National Health Interview Survey (n = 323,354). By 2006, 8,362 participants had died of cancer. Cox proportional hazards regression was used to estimate relative risks. Among current alcohol drinkers, for all-site cancer mortality, higher-quantity drinking (≥3 drinks on drinking days vs. 1 drink on drinking days) was associated with increased risk among men (relative risk (RR) = 1.24, 95% confidence interval (CI): 1.09, 1.41; P for linear trend = 0.001); higher-frequency drinking (≥3 days/week vs. cancer mortality results were similar, but among never smokers, results were null. For colorectal cancer mortality, higher-quantity drinking was associated with increased risk among women (RR = 1.93, 95% CI: 1.17, 3.18; P-trend = 0.03). Higher-frequency drinking was associated with increased risk of prostate cancer (RR = 1.55, 95% CI: 1.01, 2.38; P for quadratic effect = 0.03) and tended to be associated with increased risk of breast cancer (RR = 1.44, 95% CI: 0.96, 2.17; P-trend = 0.06). Epidemiologic studies of alcohol and cancer mortality should consider the independent effects of quantity and frequency. PMID:21965184

  8. Determining the optimal system-specific cut-off frequencies for filtering in-vitro upper extremity impact force and acceleration data by residual analysis.

    Science.gov (United States)

    Burkhart, Timothy A; Dunning, Cynthia E; Andrews, David M

    2011-10-13

    The fundamental nature of impact testing requires a cautious approach to signal processing, to minimize noise while preserving important signal information. However, few recommendations exist regarding the most suitable filter frequency cut-offs to achieve these goals. Therefore, the purpose of this investigation is twofold: to illustrate how residual analysis can be utilized to quantify optimal system-specific filter cut-off frequencies for force, moment, and acceleration data resulting from in-vitro upper extremity impacts, and to show how optimal cut-off frequencies can vary based on impact condition intensity. Eight human cadaver radii specimens were impacted with a pneumatic impact testing device at impact energies that increased from 20J, in 10J increments, until fracture occurred. The optimal filter cut-off frequency for pre-fracture and fracture trials was determined with a residual analysis performed on all force and acceleration waveforms. Force and acceleration data were filtered with a dual pass, 4th order Butterworth filter at each of 14 different cut-off values ranging from 60Hz to 1500Hz. Mean (SD) pre-fracture and fracture optimal cut-off frequencies for the force variables were 605.8 (82.7)Hz and 513.9 (79.5)Hz, respectively. Differences in the optimal cut-off frequency were also found between signals (e.g. Fx (medial-lateral), Fy (superior-inferior), Fz (anterior-posterior)) within the same test. These optimal cut-off frequencies do not universally agree with the recommendations of filtering all upper extremity impact data using a cut-off frequency of 600Hz. This highlights the importance of quantifying the filter frequency cut-offs specific to the instrumentation and experimental set-up. Improper digital filtering may lead to erroneous results and a lack of standardized approaches makes it difficult to compare findings of in-vitro dynamic testing between laboratories. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. HIV-Specific B Cell Frequency Correlates with Neutralization Breadth in Patients Naturally Controlling HIV-Infection

    Directory of Open Access Journals (Sweden)

    Angeline Rouers

    2017-07-01

    Full Text Available HIV-specific broadly neutralizing antibodies (bnAbs have been isolated from patients with high viremia but also from HIV controllers that repress HIV-1 replication. In these elite controllers (ECs, multiple parameters contribute to viral suppression, including genetic factors and immune responses. Defining the immune correlates associated with the generation of bnAbs may help in designing efficient immunotherapies. In this study, in ECs either positive or negative for the HLA-B*57 protective allele, in treated HIV-infected and HIV-negative individuals, we characterized memory B cell compartments and HIV-specific memory B cells responses using flow cytometry and ELISPOT. ECs preserved their memory B cell compartments and in contrast to treated patients, maintained detectable HIV-specific memory B cell responses. All ECs presented IgG1+ HIV-specific memory B cells but some individuals also preserved IgG2+ or IgG3+ responses. Importantly, we also analyzed the capacity of sera from ECs to neutralize a panel of HIV strains including transmitted/founder virus. 29% and 21% of HLA-B*57+ and HLA-B*57− ECs, respectively, neutralized at least 40% of the viral strains tested. Remarkably, in HLA-B*57+ ECs the frequency of HIV-Env-specific memory B cells correlated positively with the neutralization breadth suggesting that preservation of HIV-specific memory B cells might contribute to the neutralizing responses in these patients.

  10. Microwave absorption properties and mechanism of cagelike ZnO /SiO2 nanocomposites

    Science.gov (United States)

    Cao, Mao-Sheng; Shi, Xiao-Ling; Fang, Xiao-Yong; Jin, Hai-Bo; Hou, Zhi-Ling; Zhou, Wei; Chen, Yu-Jin

    2007-11-01

    In this paper, cagelike ZnO /SiO2 nanocomposites were prepared and their microwave absorption properties were investigated in detail. Dielectric constants and losses of the pure cagelike ZnO nanostructures were measured in a frequency range of 8.2-12.4GHz. The measured results indicate that the cagelike ZnO nanostructures are low-loss material for microwave absorption in X band. However, the cagelike ZnO /SiO2 nanocomposites exhibit a relatively strong attenuation to microwave in X band. Such strong absorption is related to the unique geometrical morphology of the cagelike ZnO nanostructures in the composites. The microcurrent network can be produced in the cagelike ZnO nanostructures, which contributes to the conductive loss.

  11. Frequency and specificity of red blood cell alloantibodies among ...

    African Journals Online (AJOL)

    Background: Blood transfusion usually results in production of alloantibody against one or more foreign red blood cell antigens which may complicate subsequent transfusions. The probability of alloimmunization depends on number and frequency of transfusion, antigen immunogenicity, recipient immune response and ...

  12. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  13. Low spatial frequency bias in schizophrenia is not face specific: When the integration of coarse and fine information fails

    Directory of Open Access Journals (Sweden)

    Vincent eLaprevote

    2013-05-01

    Full Text Available Studies have shown that patients with schizophrenia exhibit visual processing impairments, particularly regarding the processing of spatial frequencies. In a previous work, we found that, compared to healthy volunteers, patients were biased towards low spatial frequencies (LSF to identify facial expression at a glance. Given the ubiquity of faces in visual perception, it remains an open question whether the LSF bias is face specific or also occurs with other visual objects. Here, fifteen patients with schizophrenia and eleven healthy control adults performed a categorization task with hybrid stimuli. These stimuli were single images consisting of two different objects, a fruit and an animal, each in a specific spatial frequency range, either low (LSF or high (HSF. Observers were asked to report if they saw an animal or a fruit. The reported category demonstrated which spatial scale was preferentially perceived in each trial. In a control experiment, participants performed the same task but with images of only a single object, either a LSF or HSF filtered animal or fruit, to verify that participants could perceive both HSF or LSF when presented in isolation. The results on the categorization task showed that patients chose more frequently LSF with hybrid stimuli compared to healthy controls. However, both populations performed equally well with HSF and LSF filtered pictures in the control experiment, demonstrating that the LSF preference found with hybrid stimuli in patients was not due to an inability to perceive HSF.The LSF preference found in schizophrenia confirms our previous study conducted with faces, and shows that this LSF bias generalizes to other categories of objects. When a broad range of spatial frequencies are present in the image, as in normal conditions of viewing, patients preferentially rely on coarse visual information contained in LSF. This result may be interpreted as a dysfunction of the guidance of HSF processing by LSF

  14. Low-frequency versus high-frequency synchronisation in chirp-evoked auditory brainstem responses

    DEFF Research Database (Denmark)

    Rønne, Filip Munch; Gøtsche-Rasmussen, Kristian

    2011-01-01

    This study investigates the frequency specific contribution to the auditory brainstem response (ABR) of chirp stimuli. Frequency rising chirps were designed to compensate for the cochlear traveling wave delay, and lead to larger wave-V amplitudes than for click stimuli as more auditory nerve fibr...

  15. Hepatitis A - frequency in children with non-specific abdominal symptoms

    International Nuclear Information System (INIS)

    Malik, R.; Ghafoor, T.; Sarfraz, M.; Hasan, N.

    2004-01-01

    Objective: To study the frequency of subclinical hepatitis 'A' in children having non-specific abdominal symptoms. Subjects and Methods: Three hundred and sixty children of either gender, < 12 years of age, presenting with vague abdominal symptoms and no jaundice were evaluated for hepatitis. Eighty-eight (24.4%) children meeting the inclusion criteria of elevated serum alanine aminotransferase (ALT), twice the upper limits of normal (90 IU/L), and normal serum bilirubin were labeled as subclinical hepatitis. Results: A total of 360 children were evaluated for vague abdominal symptoms and 96 (26.7%) of them had hepatitis on laboratory profile. Eight patients developed early jaundice and were excluded from the study. Out of 88 (24.4%) cases of subclinical hepatitis, 82 (93.2%) had hepatitis-A, 03 (3.4%) had hepatitis-B, while no causative agent was found in 03 (3.4%) children. The common presenting symptoms were abdominal pain/discomfort, loss of appetite, nausea, vomiting, malaise, fatigue and fever. Hepatomegaly and splenomegaly was documented in 56% and 43% cases respectively. A history of exposure to a patient with hepatitis was present in 14/88 (15.9%) cases whereas no child was vaccinated against HAV. Serum ALT level declined to normal limits within 4 weeks for 77/88 (87.5%) cases and within 6 weeks for 84/88 (95.4%). All cases recovered spontaneously with out any complication. Conclusion: Hepatitis-A was rampant in children presenting with vague abdominal symptoms in our series. (author)

  16. Hepatitis A--frequency in children with non-specific abdominal symptoms.

    Science.gov (United States)

    Malik, Rahat; Ghafoor, Tariq; Sarfraz, Muhammad; Hasan, Najmul

    2004-06-01

    To study the frequency of subclinical hepatitis 'A' in children having non-specific abdominal symptoms. A descriptive study. This study was conducted at Combined Military Hospital (CMH), Peshawar from June to December 2000. Three hundred and sixty children of either gender, hepatitis. Eighty eight (24.4%) children meeting the inclusion criteria of elevated serum alanine aminotransferase (ALT), twice the upper limits of normal (90 IU/L), and normal serum bilirubin were labelled as subclinical hepatitis. A total of 360 children were evaluated for vague abdominal symptoms and 96 (26.7%) of them had hepatitis on laboratory profile. Eight patients developed early jaundice and were excluded from the study. Out of 88 (24.4%) cases of subclinical hepatitis, 82 (93.2%) had hepatitis-A, 03 (3.4%) had hepatitis-B, while no causative agent was found in 03 (3.4%) children. The common presenting symptoms were abdominal pain/discomfort, loss of appetite, nausea, vomiting, malaise, fatigue and fever. Hepatomegaly and splenomegaly was documented in 56% and 43% cases respectively. A history of exposure to a patient with hepatitis was present in 14/88 (15.9%) cases whereas no child was vaccinated against HAV. Serum ALT level declined to normal limits within 4 weeks for 77/88 (87.5%) cases and within 6 weeks for 84/88 (95.4%). All cases recovered spontaneously with out any complication. Hepatitis-A was rampant in children presenting with vague abdominal symptoms in our series.

  17. Radio-frequency quadrupole: general properties and specific applications

    International Nuclear Information System (INIS)

    Stokes, R.H.; Crandall, K.R.; Hamm, R.W.

    1980-01-01

    The radio-frequency quadrupole (RFQ) linac structure is being developed for the acceleration of low-velocity ions. Recent experimental tests have confirmed its expected performance and have led to an increased interest in a wide range of possible applications. The general properties of RFQ accelerators are reviewed and beam dynamics simulation results are presented for their use in a variety of accelerating systems. These include the low-beta sections of the Fusion Materials Irradiation Test Accelerator, a 200-MHz proton linear accelerator, and a xenon accelerator for heavy ion fusion

  18. Dolphins adjust species-specific frequency parameters to compensate for increasing background noise.

    Directory of Open Access Journals (Sweden)

    Elena Papale

    Full Text Available An increase in ocean noise levels could interfere with acoustic communication of marine mammals. In this study we explored the effects of anthropogenic and natural noise on the acoustic properties of a dolphin communication signal, the whistle. A towed array with four elements was used to record environmental background noise and whistles of short-beaked common-, Atlantic spotted- and striped-dolphins in the Canaries archipelago. Four frequency parameters were measured from each whistle, while Sound Pressure Levels (SPL of the background noise were measured at the central frequencies of seven one-third octave bands, from 5 to 20 kHz. Results show that dolphins increase the whistles' frequency parameters with lower variability in the presence of anthropogenic noise, and increase the end frequency of their whistles when confronted with increasing natural noise. This study provides the first evidence that the synergy among SPLs has a role in shaping the whistles' structure of these three species, with respect to both natural and anthropogenic noise.

  19. Dolphins adjust species-specific frequency parameters to compensate for increasing background noise.

    Science.gov (United States)

    Papale, Elena; Gamba, Marco; Perez-Gil, Monica; Martin, Vidal Martel; Giacoma, Cristina

    2015-01-01

    An increase in ocean noise levels could interfere with acoustic communication of marine mammals. In this study we explored the effects of anthropogenic and natural noise on the acoustic properties of a dolphin communication signal, the whistle. A towed array with four elements was used to record environmental background noise and whistles of short-beaked common-, Atlantic spotted- and striped-dolphins in the Canaries archipelago. Four frequency parameters were measured from each whistle, while Sound Pressure Levels (SPL) of the background noise were measured at the central frequencies of seven one-third octave bands, from 5 to 20 kHz. Results show that dolphins increase the whistles' frequency parameters with lower variability in the presence of anthropogenic noise, and increase the end frequency of their whistles when confronted with increasing natural noise. This study provides the first evidence that the synergy among SPLs has a role in shaping the whistles' structure of these three species, with respect to both natural and anthropogenic noise.

  20. Dolphins Adjust Species-Specific Frequency Parameters to Compensate for Increasing Background Noise

    Science.gov (United States)

    Papale, Elena; Gamba, Marco; Perez-Gil, Monica; Martin, Vidal Martel; Giacoma, Cristina

    2015-01-01

    An increase in ocean noise levels could interfere with acoustic communication of marine mammals. In this study we explored the effects of anthropogenic and natural noise on the acoustic properties of a dolphin communication signal, the whistle. A towed array with four elements was used to record environmental background noise and whistles of short-beaked common-, Atlantic spotted- and striped-dolphins in the Canaries archipelago. Four frequency parameters were measured from each whistle, while Sound Pressure Levels (SPL) of the background noise were measured at the central frequencies of seven one-third octave bands, from 5 to 20 kHz. Results show that dolphins increase the whistles’ frequency parameters with lower variability in the presence of anthropogenic noise, and increase the end frequency of their whistles when confronted with increasing natural noise. This study provides the first evidence that the synergy among SPLs has a role in shaping the whistles' structure of these three species, with respect to both natural and anthropogenic noise. PMID:25853825

  1. Nonlinear frequency conversion in fiber lasers

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian

    The concept of nonlinear frequency conversion entails generating light at new frequencies other than those of the source light. The emission wavelength of typical fiber laser systems, relying on rare-earth dopants, are constrained within specific bands of the infrared region. By exploiting...... nonlinear processes, light from these specific wavelength bands can be used to generate light at new frequencies otherwise not obtainable by rare-earth elements. This thesis describes work covering Raman fiber lasers (RFLs) and amplifiers for nonlinear frequency down-conversion, and also the method...... of fiberoptic Cherenkov radiation (FCR) using ultrafast pulses as a means for generating tunable visible (VIS) light at higher frequencies. Two different polarization maintaining (PM) RFL cavities are studied with an emphasis on stability and spectral broadening. The cavities are formed by inscription of fiber...

  2. The simultaneous ex vivo detection of low-frequency antigen-specific CD4+ and CD8+ T-cell responses using overlapping peptide pools.

    Science.gov (United States)

    Singh, Satwinder Kaur; Meyering, Maaike; Ramwadhdoebe, Tamara H; Stynenbosch, Linda F M; Redeker, Anke; Kuppen, Peter J K; Melief, Cornelis J M; Welters, Marij J P; van der Burg, Sjoerd H

    2012-11-01

    The ability to measure antigen-specific T cells at the single-cell level by intracellular cytokine staining (ICS) is a promising immunomonitoring tool and is extensively applied in the evaluation of immunotherapy of cancer. The protocols used to detect antigen-specific CD8+ T-cell responses generally work for the detection of antigen-specific T cells in samples that have undergone at least one round of in vitro pre-stimulation. Application of a common protocol but now using long peptides as antigens was not suitable to simultaneously detect antigen-specific CD8+ and CD4+ T cells directly ex vivo in cryopreserved samples. CD8 T-cell reactivity to monocytes pulsed with long peptides as antigens ranged between 5 and 25 % of that observed against monocytes pulsed with a direct HLA class I fitting minimal CTL peptide epitope. Therefore, we adapted our ICS protocol and show that the use of tenfold higher concentration of long peptides to load APC, the use of IFN-α and poly(I:C) to promote antigen processing and improve T-cell stimulation, does allow for the ex vivo detection of low-frequency antigen-specific CD8+ and CD4+ T cells in an HLA-independent setting. While most of the improvements were related to increasing the ability to measure CD8+ T-cell reactivity following stimulation with long peptides to at least 50 % of the response detected when using a minimal peptide epitope, the final analysis of blood samples from vaccinated patients successfully showed that the adapted ICS protocol also increases the ability to ex vivo detect low-frequency p53-specific CD4+ T-cell responses in cryopreserved PBMC samples.

  3. Counting Word Frequencies with Python

    Directory of Open Access Journals (Sweden)

    William J. Turkel

    2012-07-01

    Full Text Available Your list is now clean enough that you can begin analyzing its contents in meaningful ways. Counting the frequency of specific words in the list can provide illustrative data. Python has an easy way to count frequencies, but it requires the use of a new type of variable: the dictionary. Before you begin working with a dictionary, consider the processes used to calculate frequencies in a list.

  4. Very-low-frequency magnetic plasma

    International Nuclear Information System (INIS)

    Pendry, J.B.; O'Brien, S.

    2002-01-01

    We show that a set of current-carrying wires can exhibit an effective magnetic permeability at very low frequencies of a few hertz. The resonant permeability, which is negative above the resonance frequency, arises from the oscillations of the wires driven by the applied magnetic field. We show that a large, frequency-specific and tunable effective permeability can be realized for a wide range of strengths of the applied field. (author)

  5. A wide-frequency range AC magnetometer to measure the specific absorption rate in nanoparticles for magnetic hyperthermia

    International Nuclear Information System (INIS)

    Garaio, E.; Collantes, J.M.; Garcia, J.A.; Plazaola, F.; Mornet, S.; Couillaud, F.; Sandre, O.

    2014-01-01

    Measurement of specific absorption rate (SAR) of magnetic nanoparticles is crucial to assert their potential for magnetic hyperthermia. To perform this task, calorimetric methods are widely used. However, those methods are not very accurate and are difficult to standardize. In this paper, we present AC magnetometry results performed with a lab-made magnetometer that is able to obtain dynamic hysteresis-loops in the AC magnetic field frequency range from 50 kHz to 1 MHz and intensities up to 24 kA m −1 . In this work, SAR values of maghemite nanoparticles dispersed in water are measured by AC magnetometry. The so-obtained values are compared with the SAR measured by calorimetric methods. Both measurements, by calorimetry and magnetometry, are in good agreement. Therefore, the presented AC magnetometer is a suitable way to obtain SAR values of magnetic nanoparticles. - Highlights: • We propose AC magnetometry as a method to measure the specific absorption rate (SAR) of magnetic nanoparticles suitable for magnetic hyperthermia therapy. • We have built a lab-made AC magnetometer, which is able to measure magnetic dynamic hysteresis-loops of nanoparticle dispersions. • The device works with AC magnetic field intensities up to 24 kA m −1 in a frequency range from 75 kHz to 1 MHz. • The SAR values of maghemite nanoparticles around 12 nm in magnetic diameter dispersed in water are measured by the lab-made magnetometer and different calorimetric methods. • Although all methods are in good agreement, several factors (probe location, thermal inertia, losses, etc.) make calorimetric method less accurate than AC magnetometry

  6. Specific or nonspecific? Evaluation of band, baseline, and cognitive specificity of sensorimotor rhythm- and gamma-based neurofeedback.

    Science.gov (United States)

    Kober, Silvia Erika; Witte, Matthias; Neuper, Christa; Wood, Guilherme

    2017-10-01

    Neurofeedback (NF) is often criticized because of the lack of empirical evidence of its specificity. Our present study thus focused on the specificity of NF on three levels: band specificity, cognitive specificity, and baseline specificity. Ten healthy middle-aged individuals performed ten sessions of SMR (sensorimotor rhythm, 12-15Hz) NF training. A second group (N=10) received feedback of a narrow gamma band (40-43Hz). Effects of NF on EEG resting measurements (tonic EEG) and cognitive functions (memory, intelligence) were evaluated using a pre-post design. Both training groups were able to linearly increase the target training frequencies (either SMR or gamma), indicating the trainability of these EEG frequencies. Both NF training protocols led to nonspecific changes in other frequency bands during NF training. While SMR NF only led to concomitant changes in slower frequencies, gamma training affected nearly the whole power spectrum. SMR NF specifically improved memory functions. Gamma training showed only marginal effects on cognitive functions. SMR power assessed during resting measurements significantly increased after SMR NF training compared to a pre-assessment, indicating specific effects of SMR NF on baseline/tonic EEG. The gamma group did not show any pre-post changes in their EEG resting activity. In conclusion, SMR NF specifically affects cognitive functions (cognitive specificity) and tonic EEG (baseline specificity), while increasing SMR during NF training nonspecifically affects slower EEG frequencies as well (band non-specificity). Gamma NF was associated with nonspecific effects on the EEG power spectrum during training, which did not lead to considerable changes in cognitive functions or baseline EEG activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. High-frequency oscillatory ventilation in pediatric acute hypoxemic respiratory failure: disease-specific morbidity survival analysis.

    Science.gov (United States)

    Babbitt, Christopher J; Cooper, Michael C; Nussbaum, Eliezer; Liao, Eileen; Levine, Glenn K; Randhawa, Inderpal S

    2012-12-01

    Multiple ventilatory strategies for acute hypoxemic respiratory failure (AHRF) in children have been advocated, including high-frequency oscillatory ventilation (HFOV). Despite the frequent deployment of HFOV, randomized controlled trials remain elusive and currently there are no pediatric trials looking at its use. Our longitudinal study analyzed the predictive clinical outcome of HFOV in pediatric AHRF given disease-specific morbidity. A retrospective 8-year review on pediatric intensive care unit admissions with AHRF ventilated by HFOV was performed. Primary outcomes included survival, morbidity, length of stay (LOS), and factors associated with survival or mortality. A total of 102 patients underwent HFOV with a 66 % overall survival rate. Survivors had a greater LOS than nonsurvivors (p = 0.001). Mortality odds ratio (OR) for patients without bronchiolitis was 8.19 (CI = 1.02, 65.43), and without pneumonia it was 3.07 (CI = 1.12, 8.39). A lower oxygenation index (OI) after HFOV commencement and at subsequent time points analyzed predicted survival. After 24 h, mortality was associated with an OI > 35 [OR = 31.11 (CI = 3.25, 297.98)]. Sepsis-related mortality was associated with a higher baseline FiO(2) (0.88 vs. 0.65), higher OI (42 vs. 22), and augmented metabolic acidosis (pH of 7.25 vs. 7.32) evaluated 4 h on HFOV (p < 0.05). High-frequency oscillatory ventilation may be safely utilized. It has a 66 % overall survival rate in pediatric AHRF of various etiologies. Patients with morbidity limited to the respiratory system and optimized oxygenation indices are most likely to survive on HFOV.

  8. A High Frequency of HIV-Specific Circulating Follicular Helper T Cells Is Associated with Preserved Memory B Cell Responses in HIV Controllers.

    Science.gov (United States)

    Claireaux, M; Galperin, M; Benati, D; Nouël, A; Mukhopadhyay, M; Klingler, J; de Truchis, P; Zucman, D; Hendou, S; Boufassa, F; Moog, C; Lambotte, O; Chakrabarti, L A

    2018-05-08

    Follicular helper T cells (Tfh) play an essential role in the affinity maturation of the antibody response by providing help to B cells. To determine whether this CD4 + T cell subset may contribute to the spontaneous control of HIV infection, we analyzed the phenotype and function of circulating Tfh (cTfh) in patients from the ANRS CO21 CODEX cohort who naturally controlled HIV-1 replication to undetectable levels and compared them to treated patients with similarly low viral loads. HIV-specific cTfh (Tet + ), detected by Gag-major histocompatibility complex class II (MHC-II) tetramer labeling in the CD45RA - CXCR5 + CD4 + T cell population, proved more frequent in the controller group ( P = 0.002). The frequency of PD-1 expression in Tet + cTfh was increased in both groups (median, >75%) compared to total cTfh (<30%), but the intensity of PD-1 expression per cell remained higher in the treated patient group ( P = 0.02), pointing to the persistence of abnormal immune activation in treated patients. The function of cTfh, analyzed by the capacity to promote IgG secretion in cocultures with autologous memory B cells, did not show major differences between groups in terms of total IgG production but proved significantly more efficient in the controller group when measuring HIV-specific IgG production. The frequency of Tet + cTfh correlated with HIV-specific IgG production ( R = 0.71 for Gag-specific and R = 0.79 for Env-specific IgG, respectively). Taken together, our findings indicate that key cTfh-B cell interactions are preserved in controlled HIV infection, resulting in potent memory B cell responses that may play an underappreciated role in HIV control. IMPORTANCE The rare patients who spontaneously control HIV replication in the absence of therapy provide a unique model to identify determinants of an effective anti-HIV immune response. HIV controllers show signs of particularly efficient antiviral T cell responses, while their humoral response was until recently

  9. High frequency characterization of Galfenol minor flux density loops

    Directory of Open Access Journals (Sweden)

    Ling Weng

    2017-05-01

    Full Text Available This paper presents the first measurement of ring-shaped Galfenol’s high frequency-dependent minor flux density loops. The frequencies of applied AC magnetic field are 1k, 5k, 10k, 50k, 100k, 200k, 300k, 500 kHz. The measurements show that the cycle area between the flux density and magnetic field curves increase with increasing frequency. High frequency-dependent characterization, including coercivity, specific power loss, residual induction, and maximum relative permeability are discussed. Minor loops for different max induction are also measured and discussed at the same frequency 100 kHz. Minor loops with the same max induction 0.05 T for different frequencies 50, 100, 200, 300, 400 kHz are measured and specific power loss are discussed.

  10. Revisiting Frequency Reuse towards Supporting Ultra-Reliable Ubiquitous-Rate Communication

    DEFF Research Database (Denmark)

    Park, Jihong; Kim, Dong Min; Popovski, Petar

    2017-01-01

    One of the goals of 5G wireless systems stated by the NGMN alliance is to provide moderate rates (50+ Mbps) everywhere and with very high reliability. We term this service Ultra-Reliable Ubiquitous-Rate Communication (UR2C). This paper investigates the role of frequency reuse in supporting UR2C...... in the downlink. To this end, two frequency reuse schemes are considered: user-specific frequency reuse (FRu) and BS-specific frequency reuse (FRb). For a given unit frequency channel, FRu reduces the number of serving user equipments (UEs), whereas FRb directly decreases the number of interfering base stations...

  11. Measurement of CD8+ and CD4+ T Cell Frequencies Specific for EBV LMP1 and LMP2a Using mRNA-Transfected DCs.

    Directory of Open Access Journals (Sweden)

    Dae-Hee Sohn

    Full Text Available An EBV-specific cellular immune response is associated with the control of EBV-associated malignancies and lymphoproliferative diseases, some of which have been successfully treated by adoptive T cell therapy. Therefore, many methods have been used to measure EBV-specific cellular immune responses. Previous studies have mainly used autologous EBV-transformed B-lymphoblastoid cell lines (B-LCLs, recombinant viral vectors transfected or peptide pulsed dendritic cells (DCs as stimulators of CD8(+ and CD4(+ T lymphocytes. In the present study, we used an interferon-γ (IFN-γ enzyme-linked immunospot (ELISPOT assay by using isolated CD8(+ and CD4(+ T cells stimulated with mRNA-transfected DCs. The frequency of latent membrane protein 1 (LMP1-specific IFN-γ producing CD4(+ T cells was significantly higher than that of LMP2a. The frequency of IFN-γ producing CD4(+ T cells was significantly correlated with that of CD8(+ T cells in LMP1-specific immune responses (r = 0.7187, Pc < 0.0001. To determine whether there were changes in LMP1- or LMP2a-specific immune responses, subsequent peripheral blood mononuclear cells (PBMCs samples were analyzed. Significant changes were observed in 5 of the 10 donors examined, and CD4(+ T cell responses showed more significant changes than CD8(+ T cell responses. CD8(+ and CD4(+ T cells from EBV-seropositive donors secreted only the Th1 cytokines IFN-γ, TNF-α, and IL-2, while Th2 (IL-4 and Th17 (IL-17a cytokines were not detected. CD4(+ T cells secreted significantly higher cytokine levels than did CD8(+ T cells. Analysis of EBV-specific T cell responses using autologous DCs transfected with mRNA might provide a comprehensive tool for monitoring EBV infection and new insights into the pathogenesis of EBV-associated diseases.

  12. Nanohertz frequency determination for the gravity probe B high frequency superconducting quantum interference device signal.

    Science.gov (United States)

    Salomon, M; Conklin, J W; Kozaczuk, J; Berberian, J E; Keiser, G M; Silbergleit, A S; Worden, P; Santiago, D I

    2011-12-01

    In this paper, we present a method to measure the frequency and the frequency change rate of a digital signal. This method consists of three consecutive algorithms: frequency interpolation, phase differencing, and a third algorithm specifically designed and tested by the authors. The succession of these three algorithms allowed a 5 parts in 10(10) resolution in frequency determination. The algorithm developed by the authors can be applied to a sampled scalar signal such that a model linking the harmonics of its main frequency to the underlying physical phenomenon is available. This method was developed in the framework of the gravity probe B (GP-B) mission. It was applied to the high frequency (HF) component of GP-B's superconducting quantum interference device signal, whose main frequency f(z) is close to the spin frequency of the gyroscopes used in the experiment. A 30 nHz resolution in signal frequency and a 0.1 pHz/s resolution in its decay rate were achieved out of a succession of 1.86 s-long stretches of signal sampled at 2200 Hz. This paper describes the underlying theory of the frequency measurement method as well as its application to GP-B's HF science signal.

  13. THE RELATION OF FREQUENCY TO THE PHYSIOLOGICAL EFFECTS OF ULTRA-HIGH FREQUENCY CURRENTS.

    Science.gov (United States)

    Christie, R V; Loomis, A L

    1929-01-31

    1. Biological effects of electromagnetic waves emitted by a vacuum tube oscillator have been studied at frequencis ranging from 8,300,000 to 158,000,000 cycles per second (1.9 to 38 meters wave-length). 2. The effects produced on animals can be fully explained on the basis of the heat generated by high frequency currents which are induced in them. 3. No evidence was obtained to support the theory that certain wave-lengths have a specific action on living cells. 4. At frequencies below 50,000,000 cycles, the effect of these radiations on animals is proportionate to the intensity of the electro-magnetic field. As the frequency is increased beyond this point, the amount of induced current is diminished and the apparent lethality of the radiation is decreased. This can be explained by changes occurring in the dielectric properties of tissues at low wave-lengths.

  14. Frequency of educational computer use as a longitudinal predictor of educational outcome in young people with specific language impairment.

    Directory of Open Access Journals (Sweden)

    Kevin Durkin

    Full Text Available Computer use draws on linguistic abilities. Using this medium thus presents challenges for young people with Specific Language Impairment (SLI and raises questions of whether computer-based tasks are appropriate for them. We consider theoretical arguments predicting impaired performance and negative outcomes relative to peers without SLI versus the possibility of positive gains. We examine the relationship between frequency of computer use (for leisure and educational purposes and educational achievement; in particular examination performance at the end of compulsory education and level of educational progress two years later. Participants were 49 young people with SLI and 56 typically developing (TD young people. At around age 17, the two groups did not differ in frequency of educational computer use or leisure computer use. There were no associations between computer use and educational outcomes in the TD group. In the SLI group, after PIQ was controlled for, educational computer use at around 17 years of age contributed substantially to the prediction of educational progress at 19 years. The findings suggest that educational uses of computers are conducive to educational progress in young people with SLI.

  15. Frequency modulation drive for a piezoelectric motor

    Science.gov (United States)

    Mittas, Anthony

    2001-01-01

    A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f.sub.1 -.DELTA.x to f.sub.1 +.DELTA.y.

  16. A study of frequency effects on conductivity measurements

    International Nuclear Information System (INIS)

    Nurul Ain Ahmad Latif; Mahmood Dollah; Mohd Khidir Kamaron; Suaib Ibrahim

    2010-01-01

    In eddy current testing (ET), different measurement can be carry out through the selection of the test frequency. In conductivity measurement, the selection of eddy current test frequencies permits to select the specific material properties to be measured. The test frequency selected should be sufficient high that eddy current penetration is limited only to fraction of the test material thickness. This paper describes the effects of test frequency on the conductivity measurement. This experiment done by applying different values of test frequency which is 20 kHz, 100 kHz and 1 MHz. (author)

  17. Development and Validation of the Brief Folate-Specific Food Frequency Questionnaire for Young Women's Diet Assessment.

    Science.gov (United States)

    Głąbska, Dominika; Książek, Aneta; Guzek, Dominika

    2017-12-14

    The tools enabling brief assessment of folate intake may be of great value for public health purposes. The aim of the presented study was to design a brief folate-specific food frequency questionnaire for Central and Eastern European population of women, as well as to assess the validity and reproducibility of the designed Folate-Intake Calculation-Food Frequency Questionnaire (Fol-IC-FFQ) on a group of Polish women aged 20-30 years. Participants collected 3-day dietary records and completed the Fol-IC-FFQ twice (FFQ1: directly after the dietary record; and FFQ2: six weeks later). The analysis included an assessment of validity (comparison of the results of FFQ1 and 3-day dietary record) and of reproducibility (comparison of the results of FFQ1 and FFQ2). In assessment of validity, a Bland-Altman index of 5.3% was observed. In assessment of reproducibility, a Bland-Altman index of 2.7% was observed, the share of individuals classified into the same intake adequacy category was over 85%, the share of individuals classified into the same tertile was almost 75%, the weighted κ statistic indicated substantial agreement (0.67) and correlation was significant ( p = 0.0000; R = 0.7995). Assessment of the Fol-IC-FFQ revealed a satisfactory level of validity and very good level of reproducibility in the population of young Polish women. The Fol-IC-FFQ may be considered a valid tool for the assessment of folate intake in young Polish women and a promising tool for the assessment of folate intake in young women in Central and Eastern Europe.

  18. Development and Validation of a Mediterranean Oriented Culture-Specific Semi-Quantitative Food Frequency Questionnaire

    Directory of Open Access Journals (Sweden)

    Elpiniki Athanasiadou

    2016-08-01

    Full Text Available The objectives were to develop a Mediterranean oriented semi-quantitative food frequency questionnaire (FFQ and evaluate its validity in measuring energy and nutrient intakes. For FFQ development, the main challenge was to merge food items and practices reflecting cultural Mediterranean preferences with other food choices ensuing from diet transition to more westernized dietary patterns. FFQ validity was evaluated by comparing nutrient intakes against the average of two 24-h dietary recalls for 179 pregnant women. Although the mean intake values for most nutrients and energy tended to be higher when determined by the FFQ, the Cohen’s d was below 0.3. Bland-Altman plots confirmed the agreement between the two methods. Positive significant correlations ranged from 0.35 to 0.77. The proportion of women classified correctly was between 73.2% and 92.2%, whereas gross misclassification was low. Weighted kappa values were between 0.31 and 0.78, while intraclass correlation coefficients were between 0.49 and 0.89. Our methodological approach for the development and validation of this FFQ provides reliable measurements of energy, macro- and micronutrient intakes. Overall, our culture-specific FFQ could serve as a useful assessment tool in studies aiming at monitoring dietary intakes, especially in the Mediterranean region, where countries share common cultural dietary habits.

  19. Development and Validation of a Mediterranean Oriented Culture-Specific Semi-Quantitative Food Frequency Questionnaire.

    Science.gov (United States)

    Athanasiadou, Elpiniki; Kyrkou, Charikleia; Fotiou, Maria; Tsakoumaki, Foteini; Dimitropoulou, Aristea; Polychroniadou, Eleni; Menexes, Georgios; Athanasiadis, Apostolos P; Biliaderis, Costas G; Michaelidou, Alexandra-Maria

    2016-08-25

    The objectives were to develop a Mediterranean oriented semi-quantitative food frequency questionnaire (FFQ) and evaluate its validity in measuring energy and nutrient intakes. For FFQ development, the main challenge was to merge food items and practices reflecting cultural Mediterranean preferences with other food choices ensuing from diet transition to more westernized dietary patterns. FFQ validity was evaluated by comparing nutrient intakes against the average of two 24-h dietary recalls for 179 pregnant women. Although the mean intake values for most nutrients and energy tended to be higher when determined by the FFQ, the Cohen's d was below 0.3. Bland-Altman plots confirmed the agreement between the two methods. Positive significant correlations ranged from 0.35 to 0.77. The proportion of women classified correctly was between 73.2% and 92.2%, whereas gross misclassification was low. Weighted kappa values were between 0.31 and 0.78, while intraclass correlation coefficients were between 0.49 and 0.89. Our methodological approach for the development and validation of this FFQ provides reliable measurements of energy, macro- and micronutrient intakes. Overall, our culture-specific FFQ could serve as a useful assessment tool in studies aiming at monitoring dietary intakes, especially in the Mediterranean region, where countries share common cultural dietary habits.

  20. Frequency specific patterns of resting-state networks development from childhood to adolescence: A magnetoencephalography study.

    Science.gov (United States)

    Meng, Lu; Xiang, Jing

    2016-11-01

    The present study investigated frequency dependent developmental patterns of the brain resting-state networks from childhood to adolescence. Magnetoencephalography (MEG) data were recorded from 20 healthy subjects at resting-state with eyes-open. The resting-state networks (RSNs) was analyzed at source-level. Brain network organization was characterized by mean clustering coefficient and average path length. The correlations between brain network measures and subjects' age during development from childhood to adolescence were statistically analyzed in delta (1-4Hz), theta (4-8Hz), alpha (8-12Hz), and beta (12-30Hz) frequency bands. A significant positive correlation between functional connectivity with age was found in alpha and beta frequency bands. A significant negative correlation between average path lengths with age was found in beta frequency band. The results suggest that there are significant developmental changes of resting-state networks from childhood to adolescence, which matures from a lattice network to a small-world network. Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  1. Measurement of background translocation frequencies in individuals with clones

    Energy Technology Data Exchange (ETDEWEB)

    Wade, Marcelle J. [California State Univ. (CalState), Hayward, CA (United States)

    1996-08-01

    In the leukemia case the unseparated B and T lymphocytes had a high translocation frequency even after 0.0014, respectively. After purging all clones from the data, the translocation frequencies for Bio 8 and Bio 23 were 0.00750.0014 and 0.0073 metaphases were scored for chromosomal aberrations,, specifically reciprocal translocations, using fluorescence in situ hybridization (FISH). Metaphase spreads were used from two healthy, unexposed individuals (not exposed to radiation, chemotherapy or radiotherapy) and one early B- precursor acute lymphocytic leukemia (ALL) patient (metaphase spreads from both separated T lymphocytes and unseparated B and T lymphocytes were scored). All three individuals had an abnormally high translocation frequency. The high translocation frequencies resulted from clonal expansion of specific translocated chromosomes. I show in this thesis that by purging (discounting or removing) clones from the data of unexposed individuals, one can obtain true background translocation frequencies. In two cases, Bio 8 and Bio 23, the measured translocation frequency for chromosomes 1, 2 and 4 was 0.0124 purging all of the clones from the data. This high translocation frequency may be due to a low frequency of some clones and may not be recognized. The separated T lymphocytes had a higher translocation frequency than expected.

  2. Recognition of Frequency Modulated Whistle-Like Sounds by a Bottlenose Dolphin (Tursiops truncatus) and Humans with Transformations in Amplitude, Duration and Frequency

    Science.gov (United States)

    Branstetter, Brian K.; DeLong, Caroline M.; Dziedzic, Brandon; Black, Amy; Bakhtiari, Kimberly

    2016-01-01

    Bottlenose dolphins (Tursiops truncatus) use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin’s (Tursiops truncatus) ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A) in response to a specific sound (sound A) for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin’s ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin’s acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition. PMID:26863519

  3. Recognition of Frequency Modulated Whistle-Like Sounds by a Bottlenose Dolphin (Tursiops truncatus and Humans with Transformations in Amplitude, Duration and Frequency.

    Directory of Open Access Journals (Sweden)

    Brian K Branstetter

    Full Text Available Bottlenose dolphins (Tursiops truncatus use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin's (Tursiops truncatus ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A in response to a specific sound (sound A for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin's ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin's acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition.

  4. Mutation frequencies in male mice and the estimation of genetic hazards of radiation in men: (specific-locus mutations/dose-rate effect/doubling dose/risk estimation)

    International Nuclear Information System (INIS)

    Russell, W.L.; Kelly, E.M.

    1982-01-01

    Estimation of the genetic hazards of ionizing radiation in men is based largely on the frequency of transmitted specific-locus mutations induced in mouse spermatogonial stem cells at low radiation dose rates. The publication of new data on this subject has permitted a fresh review of all the information available. The data continue to show no discrepancy from the interpretation that, although mutation frequency decreases markedly as dose rate is decreased from 90 to 0.8 R/min (1 R = 2.6 X 10 -4 coulombs/kg) there seems to be no further change below 0.8 R/min over the range from that dose rate to 0.0007 R/min. Simple mathematical models are used to compute: (a) a maximum likelihood estimate of the induced mutation frequency at the low dose rates, and (b) a maximum likelihood estimate of the ratio of this to the mutation frequency at high dose rates in the range of 72 to 90 R/min. In the application of these results to the estimation of genetic hazards of radiation in man, the former value can be used to calculate a doubling dose - i.e., the dose of radiation that induces a mutation frequency equal to the spontaneous frequency. The doubling dose based on the low-dose-rate data compiled here is 110 R. The ratio of the mutation frequency at low dose rate to that at high dose rate is useful when it becomes necessary to extrapolate from experimental determinations, or from human data, at high dose rates to the expected risk at low dose rates. The ratio derived from the present analysis is 0.33

  5. Biophysical detector for definition of anomalies in Semipalatinsk nuclear test site zone

    International Nuclear Information System (INIS)

    Sokolovskaya, E.V.; Inyushin, V.M.; Kalieva, Zh.A.

    2000-01-01

    With help of space aero-survey of thermodynamical anomaly (increase of land surface temperature) in Semipalatinsk test site zone is revealed. It was suggested that it is a result of recombination processes of Earth's plasma due to entropy increase in result of plasma fluctuations called by underground nuclear explosions. This hypothesis was checked by means of territory scanning around Semipalatinsk test site with help of biophysical detectors representing isolate fragments of bio-plasma of animal and vegetation origin. It was revealed that there are anomalies in Almaty-Semipalatinsk cities' beam of Ayaguz-Semipalatinsk zone and on Omsk-Semipalatinsk beam on Semenovka-Semipalatinsk section. During passing of areas in close proximity to the nuclear site an increase of micro-currents amplitude in 4-5 μA as well as irregular amplitude change are registered. Although anomalies make up 10 % from geo-plasma's micro-currents initial values, and this value can exert significant influence on human plasma homeostasis for persons living in anomalous regions. It is concluded that it is necessary research of non-radiation effects nature of underground nuclear explosions and its action on biological status of men, animals, plants and soils

  6. International Society of Sports Nutrition position stand: meal frequency

    Directory of Open Access Journals (Sweden)

    Stout Jeffrey R

    2011-03-01

    Full Text Available Abstract Position Statement: Admittedly, research to date examining the physiological effects of meal frequency in humans is somewhat limited. More specifically, data that has specifically examined the impact of meal frequency on body composition, training adaptations, and performance in physically active individuals and athletes is scant. Until more research is available in the physically active and athletic populations, definitive conclusions cannot be made. However, within the confines of the current scientific literature, we assert that: 1. Increasing meal frequency does not appear to favorably change body composition in sedentary populations. 2. If protein levels are adequate, increasing meal frequency during periods of hypoenergetic dieting may preserve lean body mass in athletic populations. 3. Increased meal frequency appears to have a positive effect on various blood markers of health, particularly LDL cholesterol, total cholesterol, and insulin. 4. Increased meal frequency does not appear to significantly enhance diet induced thermogenesis, total energy expenditure or resting metabolic rate. 5. Increasing meal frequency appears to help decrease hunger and improve appetite control. The following literature review has been prepared by the authors in support of the aforementioned position statement.

  7. Frequency distribution of specific activities and radiological hazard assessment in surface beach sand samples collected in Bangsaen beach in Chonburi province, Thailand

    Science.gov (United States)

    Changkit, N.; Boonkrongcheep, R.; Youngchauy, U.; Polthum, S.; Kessaratikoon, P.

    2017-09-01

    The specific activities of natural radionuclides (40K, 226Ra and 232Th) in 50 surface beach sand samples collected from Bangsaen beach in Chonburi province in the easthern region of Thailand, were measured and evaluated. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system in the special laboratory at Thailand Institute of Nuclear Technology (Public Organization). The IAEA-SOIL-375 reference material was used to analyze the concentration of 40K, 226Ra and 232Th in all samples. It was found that the specific activities of 40K, 226Ra and 232Th were ranged from 510.85 - 771.35, 8.17 - 17.06 and 4.25 - 15.68 Bq/kg. Furthermore, frequency distribution of the specific activities were studied, analyzed and found to be the asymmetrical distribution by using a statistical computer program. Moreover, four radiological hazard indices for the investigated area were also calculated by using the median values of specific activities of 40K, 226Ra and 232Th. The results were also compared with the Office of Atoms for Peace (OAP) annual report data, Thailand and global radioactivity measurement and evaluations.

  8. Frequency Assignment for Joint Aerial Layer Network High-Capacity Backbone

    Science.gov (United States)

    2017-08-11

    Two Frequency Assignment Problems (FAPs) are considered in this work, which are called MMC-FAP and MS-FAP. MMC-FAP is to minimize the frequency usage... minimize the frequency span in both frequency bands. By exploiting problem-specific properties, MMC-FAP can be formulated as a Mixed Integer Linear...considered for JALN HCB. The first FAP problem, called MMC- FAP, is to minimize the frequency usage of the most congested aerial platform in both

  9. EVALUATION OF DIFFERENT FEEDING FREQUENCIES ON ...

    African Journals Online (AJOL)

    USER

    EVALUATION OF DIFFERENT FEEDING FREQUENCIES ON GROWTH .... using one-way analysis of variance (ANOVA) and ... SGR = Specific Growth Rate, FCR = Food Conversion Ratio, K = Condition Factor and SR = Survival Rate.

  10. Sources for high frequency heating. Performance and limitations

    International Nuclear Information System (INIS)

    Le Gardeur, R.

    1976-01-01

    The various problems encountered in high frequency heating of plasmas can be decomposed into three spheres of action: theoretical development, antenna designing, and utilization of power sources. By classifying heating into three spectral domains, present and future needs are enumerated. Several specific antenna designs are treated. High frequency power sources are reviewed. The actual development of the gyratron is discussed in view of future needs in very high frequency heating of plasmas [fr

  11. Effects of first formant onset frequency on [-voice] judgments result from auditory processes not specific to humans.

    Science.gov (United States)

    Kluender, K R; Lotto, A J

    1994-02-01

    When F1-onset frequency is lower, longer F1 cut-back (VOT) is required for human listeners to perceive synthesized stop consonants as voiceless. K. R. Kluender [J. Acoust. Soc. Am. 90, 83-96 (1991)] found comparable effects of F1-onset frequency on the "labeling" of stop consonants by Japanese quail (coturnix coturnix japonica) trained to distinguish stop consonants varying in F1 cut-back. In that study, CVs were synthesized with natural-like rising F1 transitions, and endpoint training stimuli differed in the onset frequency of F1 because a longer cut-back resulted in a higher F1 onset. In order to assess whether earlier results were due to auditory predispositions or due to animals having learned the natural covariance between F1 cut-back and F1-onset frequency, the present experiment was conducted with synthetic continua having either a relatively low (375 Hz) or high (750 Hz) constant-frequency F1. Six birds were trained to respond differentially to endpoint stimuli from three series of synthesized /CV/s varying in duration of F1 cut-back. Second and third formant transitions were appropriate for labial, alveolar, or velar stops. Despite the fact that there was no opportunity for animal subjects to use experienced covariation of F1-onset frequency and F1 cut-back, quail typically exhibited shorter labeling boundaries (more voiceless stops) for intermediate stimuli of the continua when F1 frequency was higher. Responses by human subjects listening to the same stimuli were also collected. Results lend support to the earlier conclusion that part or all of the effect of F1 onset frequency on perception of voicing may be adequately explained by general auditory processes.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Stimulus-specific suppression preserves information in auditory short-term memory.

    Science.gov (United States)

    Linke, Annika C; Vicente-Grabovetsky, Alejandro; Cusack, Rhodri

    2011-08-02

    Philosophers and scientists have puzzled for millennia over how perceptual information is stored in short-term memory. Some have suggested that early sensory representations are involved, but their precise role has remained unclear. The current study asks whether auditory cortex shows sustained frequency-specific activation while sounds are maintained in short-term memory using high-resolution functional MRI (fMRI). Investigating short-term memory representations within regions of human auditory cortex with fMRI has been difficult because of their small size and high anatomical variability between subjects. However, we overcame these constraints by using multivoxel pattern analysis. It clearly revealed frequency-specific activity during the encoding phase of a change detection task, and the degree of this frequency-specific activation was positively related to performance in the task. Although the sounds had to be maintained in memory, activity in auditory cortex was significantly suppressed. Strikingly, patterns of activity in this maintenance period correlated negatively with the patterns evoked by the same frequencies during encoding. Furthermore, individuals who used a rehearsal strategy to remember the sounds showed reduced frequency-specific suppression during the maintenance period. Although negative activations are often disregarded in fMRI research, our findings imply that decreases in blood oxygenation level-dependent response carry important stimulus-specific information and can be related to cognitive processes. We hypothesize that, during auditory change detection, frequency-specific suppression protects short-term memory representations from being overwritten by inhibiting the encoding of interfering sounds.

  13. Facet-specific interaction between methanol and TiO2 probed by sum-frequency vibrational spectroscopy.

    Science.gov (United States)

    Yang, Deheng; Li, Yadong; Liu, Xinyi; Cao, Yue; Gao, Yi; Shen, Y Ron; Liu, Wei-Tao

    2018-04-24

    The facet-specific interaction between molecules and crystalline catalysts, such as titanium dioxides (TiO 2 ), has attracted much attention due to possible facet-dependent reactivity. Using surface-sensitive sum-frequency vibrational spectroscopy, we have studied how methanol interacts with different common facets of crystalline TiO 2 , including rutile(110), (001), (100), and anatase(101), under ambient temperature and pressure. We found that methanol adsorbs predominantly in the molecular form on all of the four surfaces, while spontaneous dissociation into methoxy occurs preferentially when these surfaces become defective. Extraction of Fermi resonance coupling between stretch and bending modes of the methyl group in analyzing adsorbed methanol spectra allows determination of the methanol adsorption isotherm. The isotherms obtained for the four surfaces are nearly the same, yielding two adsorbed Gibbs free energies associated with two different adsorption configurations singled out by ab initio calculations. They are ( i ) ∼-20 kJ/mol for methanol with its oxygen attached to a low-coordinated surface titanium, and ( ii ) ∼-5 kJ/mol for methanol hydrogen-bonded to a surface oxygen and a neighboring methanol molecule. Despite similar adsorption energetics, the Fermi resonance coupling strength for adsorbed methanol appears to depend sensitively on the surface facet and coverage.

  14. Frequency dependent polarization in blazars

    International Nuclear Information System (INIS)

    Bjoernsson, C.I.

    1984-10-01

    It is argued that the intrinsic frequency dependent polarization in blazars finds its most straightforward explanations in terms of a single rather than a multicomponent sourcemodel. In order to reproduce the observations, under the assumption that the emission mechanism is optically thin synchrotron radiation, both a well ordered magnetic field and an electron distribution with a sharp break or cuttoff are necessary. Non-uniform pitch angle distribution and/or environments where synchrotron losses are important are both conducive to producing strong frequency dependent polarization. Reasons are put forth as to why such conditions ar expected to occur in blazars. Two specific models are discussed in detail and it is shown that they are both able to produce strong frequency dependent polarization, even when the spectral index changes by a small amount only. (orig.)

  15. Loads as a Resource: Frequency Responsive Demand

    Energy Technology Data Exchange (ETDEWEB)

    Kalsi, Karanjit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lian, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Marinovici, Laurentiu D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhang, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moya, Christian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-10-08

    Frequency control plays an important role in preserving the power balance of a multi-machine power system. Generators modify their power output when a non-zero frequency deviation is presented in order to restore power balance across the network. However, with plans for large-scale penetration of renewable energy resources, performing primary frequency control using only supply-side resources becomes not only prohibitively expensive, but also technically difficult. Frequency control from the demand side or load control presents a novel and viable way for providing the desired frequency response. Loads can measure frequency locally and change their power consumption after a non-zero frequency deviation is presented in order to achieve power balance between generation and consumption. The specific objectives of this project are to: •Provide a framework to facilitate large-scale deployment of frequency responsive end-use devices •Systematically design decentralized frequency-based load control strategies for enhanced stability performance •Ensure applicability over wide range of operating conditions while accounting for unpredictable end-use behavior and physical device constraints •Test and validate control strategy using large-scale simulations and field demonstrations •Create a level-playing field for smart grid assets with conventional generators

  16. Age-Specific Frequencies and Characteristics of Ovarian Cysts in Children and Adolescents

    OpenAIRE

    Emeksiz, Hamdi Cihan; Derin?z, Ok?an; Akkoyun, Esra Bet?l; G??l? P?narl?, Faruk; Bideci, Aysun

    2017-01-01

    Objective: The aim of the present study was to document ovarian cyst frequency and characteristics as well as distribution of these parameters with respect to age in children and adolescents. Methods: We retrospectively analyzed the medical records of 1009 girls between the ages of 5-18 years who presented to our pediatric emergency department (PED) with pelvic pain and therefore underwent pelvic ultrasound examination between June 2011 and May 2014. Results: In total, 132 of 1009 girls (13.1...

  17. The frequencies of IFNγ+IL2+TNFα+ PPD-specific CD4+CD45RO+ T-cells correlate with the magnitude of the QuantiFERON® gold in-tube response in a prospective study of healthy indian adolescents.

    Science.gov (United States)

    Jenum, Synne; Grewal, Harleen M S; Hokey, David A; Kenneth, John; Vaz, Mario; Doherty, Timothy Mark; Jahnsen, Frode Lars

    2014-01-01

    QuantiFERON-TB Gold In-Tube (QFT) is an IFNγ-release assay used in the diagnosis of Mycobacterium tuberculosis (MTB) infection. The risk of TB progression increases with the magnitude of the MTB-specific IFNγ-response. QFT reversion, also associated with low Tuberculin Skin Test responses, may therefore represent a transient immune response with control of M. tuberculosis infection. However, studies at the single cell level have suggested that the quality (polyfunctionality) of the T-cell response is more important than the quantity of cytokines produced. To explore the quality and/or magnitude of mycobacteria-specific T-cell responses associated with QFT reversion and persistent QFT-positivity. Multi-color flowcytometry on prospectively collected peripheral blood mononuclear cells was applied to assess mycobacteria-specific T-cell responses in 42 QFT positive Indian adolescents of whom 21 became QFT negative (reverters) within one year. Ten QFT consistent negatives were also included as controls. There was no difference in the qualitative PPD-specific CD4+ T-cell response between QFT consistent positives and reverters. However, compared with QFT consistent positives, reverters displayed lower absolute frequencies of polyfunctional (IFNγ+IL2+TNFα+) CD4+ T-cells at baseline, which were further reduced to the point where they were not different to QFT negative controls one year later. Moreover, absolute frequencies of these cells correlated well with the magnitude of the QFT-response. Whereas specific polyfunctional CD4+ T-cells have been suggested to protect against TB progression, our data do not support that higher relative or absolute frequencies of PPD-specific polyfunctional CD4+ T-cells in peripheral blood can explain the reduced risk of TB progression observed in QFT reverters. On the contrary, absolute frequencies of these cells correlated with the QFT-response, suggesting that this readout reflects antigenic load.

  18. Iodine frequency references for space

    International Nuclear Information System (INIS)

    Schuldt, Thilo; Braxmaier, Claus; Döringshoff, Klaus; Peters, Achim; Oswald, Markus; Johann, Ulrich

    2017-01-01

    Optical frequency references are a key element for the realization of future space missions. They are needed for missions related to tests of fundamental physics, gravitational wave detection, Earth observation and navigation and ranging. In missions such as GRACE follow-on or LISA the optical frequency reference is used as light source for high-sensitivity inter-satellite distance metrology. While cavity-based systems are current baseline e.g. for LISA, frequency stabilization on a hyperfine transition in molecular iodine near 532 nm is a promising alternative. Due to its absolute frequency, iodine standards crucially simplify the initial spacecraft acquisition procedures. Current setups fulfill the GRACE-FO and LISA frequency stability requirements and are realized near Engineering Model level. We present the current status of our developments on Elegant Breadboard (EBB) and Engineering Model (EM) level taking into account specific design criteria for space compatibility such as compactness (size iodine spectroscopy EM: 38 × 18 × 10 cm 3 ) and robustness. Both setups achieved similar frequency stabilities of ∼ 1 · 10 −14 at an integration time of 1 s and below 5 · 10 −15 at integration times between 10 s and 1000 s. Furthermore, we present an even more compact design currently developed for a sounding rocket mission with launch in 2017. (paper)

  19. Modelling of word usage frequency dynamics using artificial neural network

    International Nuclear Information System (INIS)

    Maslennikova, Yu S; Bochkarev, V V; Voloskov, D S

    2014-01-01

    In this paper the method for modelling of word usage frequency time series is proposed. An artificial feedforward neural network was used to predict word usage frequencies. The neural network was trained using the maximum likelihood criterion. The Google Books Ngram corpus was used for the analysis. This database provides a large amount of data on frequency of specific word forms for 7 languages. Statistical modelling of word usage frequency time series allows finding optimal fitting and filtering algorithm for subsequent lexicographic analysis and verification of frequency trend models

  20. Low-frequency scaling applied to stochastic finite-fault modeling

    Science.gov (United States)

    Crane, Stephen; Motazedian, Dariush

    2014-01-01

    Stochastic finite-fault modeling is an important tool for simulating moderate to large earthquakes. It has proven to be useful in applications that require a reliable estimation of ground motions, mostly in the spectral frequency range of 1 to 10 Hz, which is the range of most interest to engineers. However, since there can be little resemblance between the low-frequency spectra of large and small earthquakes, this portion can be difficult to simulate using stochastic finite-fault techniques. This paper introduces two different methods to scale low-frequency spectra for stochastic finite-fault modeling. One method multiplies the subfault source spectrum by an empirical function. This function has three parameters to scale the low-frequency spectra: the level of scaling and the start and end frequencies of the taper. This empirical function adjusts the earthquake spectra only between the desired frequencies, conserving seismic moment in the simulated spectra. The other method is an empirical low-frequency coefficient that is added to the subfault corner frequency. This new parameter changes the ratio between high and low frequencies. For each simulation, the entire earthquake spectra is adjusted, which may result in the seismic moment not being conserved for a simulated earthquake. These low-frequency scaling methods were used to reproduce recorded earthquake spectra from several earthquakes recorded in the Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation Models (NGA) database. There were two methods of determining the stochastic parameters of best fit for each earthquake: a general residual analysis and an earthquake-specific residual analysis. Both methods resulted in comparable values for stress drop and the low-frequency scaling parameters; however, the earthquake-specific residual analysis obtained a more accurate distribution of the averaged residuals.

  1. Configuration-specific kinetic theory applied to an ideal binary gas mixture.

    Science.gov (United States)

    Wiseman, Floyd L

    2006-10-05

    This paper is the second in a two-part series dealing with the configuration-specific analyses for molecular collision events of hard, spherical molecules at thermal equilibrium. The first paper analyzed a single-component system, and the reader is referred to it for the fundamental concepts. In this paper, the expressions for the configuration-specific collision frequencies and the average line-of-centers collision angles and speeds are derived for an ideal binary gas mixture. The analyses show that the average line-of-centers quantities are all dependent upon the ratio of the masses of the two components, but not upon molecular size. Of course, the configuration-specific collision frequencies do depend on molecular size. The expression for the overall binary collision frequency is a simple sum of the configuration-specific collision frequencies and is identical to the conventional expression.

  2. NMDA receptor antagonist-enhanced high frequency oscillations: are they generated broadly or regionally specific?

    Science.gov (United States)

    Olszewski, Maciej; Dolowa, Wioleta; Matulewicz, Pawel; Kasicki, Stefan; Hunt, Mark J

    2013-12-01

    Systemic administration of NMDA receptor antagonists, used to model schizophrenia, increase the power of high-frequency oscillations (130-180Hz, HFO) in a variety of neuroanatomical and functionally distinct brain regions. However, it is unclear whether HFO are independently and locally generated or instead spread from a distant source. To address this issue, we used local infusion of tetrodotoxin (TTX) to distinct brain areas to determine how accurately HFO recorded after injection of NMDAR antagonists reflect the activity actually generated at the electrode tip. Changes in power were evaluated in local field potentials (LFPs) recorded from the nucleus accumbens (NAc), prefrontal cortex and caudate and in electrocorticograms (ECoGs) from visual and frontal areas. HFO recorded in frontal and visual cortices (ECoGs) or in the prefrontal cortex, caudate (LFPs) co-varied in power and frequency with observed changes in the NAc. TTX infusion to the NAc immediately and profoundly reduced the power of accumbal HFO which correlated with changes in HFO recorded in distant cortical sites. In contrast, TTX infusion to the prefrontal cortex did not change HFO power recorded locally, although gamma power was reduced. A very similar result was found after TTX infusion to the caudate. These findings raise the possibility that the NAc is an important neural generator. Our data also support existing studies challenging the idea that high frequencies recorded in LFPs are necessarily generated at the recording site. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

  3. Frequency-dependent changes in the amplitude of low-frequency fluctuations in Internet gaming disorder

    Directory of Open Access Journals (Sweden)

    Xiao eLin

    2015-09-01

    Full Text Available Neuroimaging studies have revealed that the task-related functional brain activities are impaired in Internet gaming disorder (IGD subjects. However, little is known about the alternations in spontaneous brain activities about them. Recent studies have proposed that the brain activities of different frequency ranges are generated by different nervous activities and have different physiological and psychological functions. Thus, in this study, we set to explore the spontaneous brain activities in IGD subjects by measuring the fractional amplitude of low-frequency fluctuation (fALFF, to investigate band-specific changes of resting-state fALFF. We subdivided the frequency range into five bands based on literatures. Comparing to healthy controls, the IGD group showed decreased fALFF values in the cerebellum posterior lobe and increased fALFF values in superior temporal gyrus. Significant interactions between frequency bands and groups were found in the cerebellum, the anterior cingulate, the lingual gyrus, the middle temporal gyrus and the middle frontal gyrus. Those brain regions are proved related to the executive function and decision-making. These results revealed the changed spontaneous brain activity of IGD, which contributed to understanding the underlying pathophysiology of IGD.

  4. Food frequency questionnaires.

    Science.gov (United States)

    Pérez Rodrigo, Carmen; Aranceta, Javier; Salvador, Gemma; Varela-Moreiras, Gregorio

    2015-02-26

    Food Frequency Questionnaires are dietary assessment tools widely used in epidemiological studies investigating the relationship between dietary intake and disease or risk factors since the early '90s. The three main components of these questionnaires are the list of foods, frequency of consumption and the portion size consumed. The food list should reflect the food habits of the study population at the time the data is collected. The frequency of consumption may be asked by open ended questions or by presenting frequency categories. Qualitative Food Frequency Questionnaires do not ask about the consumed portions; semi-quantitative include standard portions and quantitative questionnaires ask respondents to estimate the portion size consumed either in household measures or grams. The latter implies a greater participant burden. Some versions include only close-ended questions in a standardized format, while others add an open section with questions about some specific food habits and practices and admit additions to the food list for foods and beverages consumed which are not included. The method can be self-administered, on paper or web-based, or interview administered either face-to-face or by telephone. Due to the standard format, especially closed-ended versions, and method of administration, FFQs are highly cost-effective thus encouraging its widespread use in large scale epidemiological cohort studies and also in other study designs. Coding and processing data collected is also less costly and requires less nutrition expertise compared to other dietary intake assessment methods. However, the main limitations are systematic errors and biases in estimates. Important efforts are being developed to improve the quality of the information. It has been recommended the use of FFQs with other methods thus enabling the adjustments required. Copyright AULA MEDICA EDICIONES 2015. Published by AULA MEDICA. All rights reserved.

  5. High frequency conductivity in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    S. S. Abukari

    2012-12-01

    Full Text Available We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω < ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity.

  6. Geographical distribution of hot flash frequencies: considering climatic influences.

    Science.gov (United States)

    Sievert, Lynnette Leidy; Flanagan, Erin K

    2005-10-01

    Laboratory studies suggest that hot flashes are triggered by small elevations in core body temperature acting within a reduced thermoneutral zone, i.e., the temperature range in which a woman neither shivers nor sweats. In the present study, it was hypothesized that women in different populations develop climate-specific thermoneutral zones, and ultimately, population-specific frequencies of hot flashes at menopause. Correlations were predicted between hot flash frequencies and latitude, elevation, and annual temperatures. Data on hot flash frequencies were drawn from 54 studies. Pearson correlation analyses and simple linear regressions were applied, first using all studies, and second using a subset of studies that included participants only to age 60 (n = 36). Regressions were repeated with all studies, controlling for method of hot flash assessment. When analyses were restricted to studies that included women up to age 60, average temperature of the coldest month was a significant predictor of hot flash frequency (P hottest and coldest temperatures was also a significant predictor (P coldest month, difference between hottest and coldest temperatures, and mean annual temperature were significant predictors of hot flash frequency. Women reported fewer hot flashes in warmer temperatures, and more hot flashes with increasing seasonality. These results suggest that acclimatization to coldest temperatures or sensitivity to seasonality may explain part of the population variation in hot flash frequency.

  7. Chemical and radiochemical specifications - PWR power plants; Specifications chimiques et radiochimiques - Centrales REP

    Energy Technology Data Exchange (ETDEWEB)

    Stutzmann, A [Electricite de France (EDF), 93 - Saint-Denis (France)

    1997-07-01

    Published by EDF this document gives the chemical specifications of the PWR (Pressurized Water Reactor) nuclear power plants. Among the chemical parameters, some have to be respected for the safety. These parameters are listed in the STE (Technical Specifications of Exploitation). The values to respect, the analysis frequencies and the time states of possible drops are noticed in this document with the motion STE under the concerned parameter. (A.L.B.)

  8. Comparative study of approaches to estimate pipe break frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Simola, K.; Pulkkinen, U.; Talja, H.; Saarenheimo, A.; Karjalainen-Roikonen, P. [VTT Industrial Systems (Finland)

    2002-12-01

    The report describes the comparative study of two approaches to estimate pipe leak and rupture frequencies for piping. One method is based on a probabilistic fracture mechanistic (PFM) model while the other one is based on statistical estimation of rupture frequencies from a large database. In order to be able to compare the approaches and their results, the rupture frequencies of some selected welds have been estimated using both of these methods. This paper highlights the differences both in methods, input data, need and use of plant specific information and need of expert judgement. The study focuses on one specific degradation mechanism, namely the intergranular stress corrosion cracking (IGSCC). This is the major degradation mechanism in old stainless steel piping in BWR environment, and its growth is influenced by material properties, stresses and water chemistry. (au)

  9. Frequency-dependent changes in amplitude of low-frequency oscillations in depression: A resting-state fMRI study.

    Science.gov (United States)

    Wang, Li; Kong, Qingmei; Li, Ke; Su, Yunai; Zeng, Yawei; Zhang, Qinge; Dai, Wenji; Xia, Mingrui; Wang, Gang; Jin, Zhen; Yu, Xin; Si, Tianmei

    2016-02-12

    We conducted this fMRI study to examine whether the alterations in amplitudes of low-frequency oscillation (LFO) of major depressive disorder (MDD) patients were frequency dependent. The LFO amplitudes (as indexed by amplitude of low-frequency fluctuation [ALFF] and fractional ALFF [fALFF]) within 4 narrowly-defined frequency bands (slow-5: 0.01-0.027Hz, slow-4: 0.027-0.073Hz, slow-3: 0.073-0.198Hz, and slow-2: 0.198-0.25Hz) were computed using resting-state fMRI data of 35 MDD patients and 32 healthy subjects. Repeated-measures analysis of variance (ANOVA) was performed on ALFF and fALFF both within the low frequency bands of slow-4 and slow-5 and within all of the four bands. We observed significant main effects of group and frequency on ALFF and fALFF in widely distributed brain regions. Importantly, significant group and frequency interaction effects were observed in the ventromedial prefrontal cortex, inferior frontal gyrus, precentral gyrus, in a left-sided fashion, the bilateral posterior cingulate and precuneus, during ANOVA both within slow-4 and slow-5 bands and within all the frequency bands. The results suggest that the alterations of LFO amplitudes in specific brain regions in MDD patients could be more sensitively detected in the slow-5 rather than the slow-4 bands. The findings may provide guidance for the frequency choice of future resting-state fMRI studies of MDD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Evaluation of cephalogram using multi-objective frequency processing

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Sakae; Takizawa, Tsutomu; Osako, Miho; Kaneda, Takashi; Kasai, Kazutaka [Nihon Univ., Chiba (Japan). School of Dentistry at Matsudo

    2002-12-01

    A diagnosis with cephalogram is important for orthodontic treatment. Recently, computed radiography (CR) has been performed to the cephalogram. However, evaluation of multi-objective frequency processing (MFP) for cephalograms has been received little attention. The purpose of this study was to evaluate the cephalogram using MFP CR. At first, 450 lateral cephalograms were made, from 50 orthodontic patients, with 9 possible spatial frequency parameter combinations and a contrast scale held fixed in images processing. For each film, the clarity of radiographic images were estimated and scored with respect to landmark identification (total 26 points, 20 points of hard tissue and 6 points of soft tissue). A specific combination of spatial frequency scales (multi-frequency balance types (MRB) F-type, multi-frequency enhancement (MRE) 8) was proved to be adequate to achieve the optimal image quality in the cephalogram. (author)

  11. Evaluation of cephalogram using multi-objective frequency processing

    International Nuclear Information System (INIS)

    Hagiwara, Sakae; Takizawa, Tsutomu; Osako, Miho; Kaneda, Takashi; Kasai, Kazutaka

    2002-01-01

    A diagnosis with cephalogram is important for orthodontic treatment. Recently, computed radiography (CR) has been performed to the cephalogram. However, evaluation of multi-objective frequency processing (MFP) for cephalograms has been received little attention. The purpose of this study was to evaluate the cephalogram using MFP CR. At first, 450 lateral cephalograms were made, from 50 orthodontic patients, with 9 possible spatial frequency parameter combinations and a contrast scale held fixed in images processing. For each film, the clarity of radiographic images were estimated and scored with respect to landmark identification (total 26 points, 20 points of hard tissue and 6 points of soft tissue). A specific combination of spatial frequency scales (multi-frequency balance types (MRB) F-type, multi-frequency enhancement (MRE) 8) was proved to be adequate to achieve the optimal image quality in the cephalogram. (author)

  12. Digital Filters for Low Frequency Equalization

    DEFF Research Database (Denmark)

    Tyril, Marni; Abildgaard, J.; Rubak, Per

    2001-01-01

    Digital filters with high resolution in the low-frequency range are studied. Specifically, for a given computational power, traditional IIR filters are compared with warped FIR filters, warped IIR filters, and modified warped FIR filters termed warped individual z FIR filters (WizFIR). The results...

  13. HIV Controllers Exhibit Enhanced Frequencies of Major Histocompatibility Complex Class II Tetramer+ Gag-Specific CD4+ T Cells in Chronic Clade C HIV-1 Infection.

    Science.gov (United States)

    Laher, Faatima; Ranasinghe, Srinika; Porichis, Filippos; Mewalal, Nikoshia; Pretorius, Karyn; Ismail, Nasreen; Buus, Søren; Stryhn, Anette; Carrington, Mary; Walker, Bruce D; Ndung'u, Thumbi; Ndhlovu, Zaza M

    2017-04-01

    Immune control of viral infections is heavily dependent on helper CD4 + T cell function. However, the understanding of the contribution of HIV-specific CD4 + T cell responses to immune protection against HIV-1, particularly in clade C infection, remains incomplete. Recently, major histocompatibility complex (MHC) class II tetramers have emerged as a powerful tool for interrogating antigen-specific CD4 + T cells without relying on effector functions. Here, we defined the MHC class II alleles for immunodominant Gag CD4 + T cell epitopes in clade C virus infection, constructed MHC class II tetramers, and then used these to define the magnitude, function, and relation to the viral load of HIV-specific CD4 + T cell responses in a cohort of untreated HIV clade C-infected persons. We observed significantly higher frequencies of MHC class II tetramer-positive CD4 + T cells in HIV controllers than progressors ( P = 0.0001), and these expanded Gag-specific CD4 + T cells in HIV controllers showed higher levels of expression of the cytolytic proteins granzymes A and B. Importantly, targeting of the immunodominant Gag41 peptide in the context of HLA class II DRB1*1101 was associated with HIV control ( r = -0.5, P = 0.02). These data identify an association between HIV-specific CD4 + T cell targeting of immunodominant Gag epitopes and immune control, particularly the contribution of a single class II MHC-peptide complex to the immune response against HIV-1 infection. Furthermore, these results highlight the advantage of the use of class II tetramers in evaluating HIV-specific CD4 + T cell responses in natural infections. IMPORTANCE Increasing evidence suggests that virus-specific CD4 + T cells contribute to the immune-mediated control of clade B HIV-1 infection, yet there remains a relative paucity of data regarding the role of HIV-specific CD4 + T cells in shaping adaptive immune responses in individuals infected with clade C, which is responsible for the majority of HIV

  14. Amplitude of Low-Frequency Fluctuations in Multiple-Frequency Bands in Acute Mild Traumatic Brain Injury.

    Science.gov (United States)

    Zhan, Jie; Gao, Lei; Zhou, Fuqing; Bai, Lijun; Kuang, Hongmei; He, Laichang; Zeng, Xianjun; Gong, Honghan

    2016-01-01

    Functional disconnectivity during the resting state has been observed in mild traumatic brain injury (mTBI) patients during the acute stage. However, it remains largely unknown whether the abnormalities are related to specific frequency bands of the low-frequency oscillations (LFO). Here, we used the amplitude of low-frequency fluctuations (ALFF) to examine the amplitudes of LFO in different frequency bands (slow-5: 0.01-0.027 Hz; slow-4: 0.027-0.073 Hz; and typical: 0.01-0.08 Hz) in patients with acute mTBI. A total of 24 acute mTBI patients and 24 age-, sex-, and education-matched healthy controls participated in this study. In the typical band, acute mTBI patients showed lower standardized ALFF in the right middle frontal gyrus and higher standardized ALFF in the right lingual/fusiform gyrus and left middle occipital gyrus. Further analyses showed that the difference between groups was concentrated in a narrower (slow-4) frequency band. In the slow-5 band, mTBI patients only exhibited higher standardized ALFF in the occipital areas. No significant correlation between the mini-mental state examination score and the standardized ALFF value was found in any brain region in the three frequency bands. Finally, no significant interaction between frequency bands and groups was found in any brain region. We concluded that the abnormality of spontaneous brain activity in acute mTBI patients existed in the frontal lobe as well as in distributed brain regions associated with integrative, sensory, and emotional roles, and the abnormal spontaneous neuronal activity in different brain regions could be better detected by the slow-4 band. These findings might contribute to a better understanding of local neural psychopathology of acute mTBI. Future studies should take the frequency bands into account when measuring intrinsic brain activity of mTBI patients.

  15. Amplitude of low-frequency fluctuations in multiple-frequency bands in acute mild traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Jie eZhan

    2016-02-01

    Full Text Available Functional disconnectivity during the resting state has been observed in mild traumatic brain injury (mTBI patients during the acute stage. However, it remains largely unknown whether the abnormalities are related to specific frequency bands of the low-frequency oscillations (LFO. Here, we used the amplitude of low-frequency fluctuations (ALFF to examine the amplitudes of LFO in different frequency bands (slow-5: 0.01–0.027 Hz; slow-4: 0.027–0.073 Hz; and typical: 0.01–0.08 Hz in patients with acute mTBI. A total of 24 acute mTBI patients and 24 age-, sex-, and education-matched healthy controls (HC participated in this study. In the typical band, acute mTBI patients showed lower standardized ALFF in the right middle frontal gyrus and higher standardized ALFF in the right lingual/fusiform gyrus and left middle occipital gyrus. Further analyses showed that the difference between groups was concentrated in a narrower (slow-4 frequency band. In the slow-5 band, mTBI patients only exhibited higher standardized ALFF in the occipital areas. No significant correlation between the MMSE score and the standardized ALFF value was found in any brain region in the three frequency bands. Finally, no significant interaction between frequency bands and groups was found in any brain region. We concluded that the abnormality of spontaneous brain activity in acute mTBI patients existed in the frontal lobe as well as in distributed brain regions associated with integrative, sensory and emotional roles, and the abnormal spontaneous neuronal activity in different brain regions could be better detected by the slow-4 band. These findings might contribute to a better understanding of local neural psychopathology of acute mTBI. Future studies should take the frequency bands into account when measuring intrinsic brain activity of mTBI patients.

  16. Improving the Specificity of EEG for Diagnosing Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    François-B. Vialatte

    2011-01-01

    Full Text Available Objective. EEG has great potential as a cost-effective screening tool for Alzheimer's disease (AD. However, the specificity of EEG is not yet sufficient to be used in clinical practice. In an earlier study, we presented preliminary results suggesting improved specificity of EEG to early stages of Alzheimer's disease. The key to this improvement is a new method for extracting sparse oscillatory events from EEG signals in the time-frequency domain. Here we provide a more detailed analysis, demonstrating improved EEG specificity for clinical screening of MCI (mild cognitive impairment patients. Methods. EEG data was recorded of MCI patients and age-matched control subjects, in rest condition with eyes closed. EEG frequency bands of interest were θ (3.5–7.5 Hz, α1 (7.5–9.5 Hz, α2 (9.5–12.5 Hz, and β (12.5–25 Hz. The EEG signals were transformed in the time-frequency domain using complex Morlet wavelets; the resulting time-frequency maps are represented by sparse bump models. Results. Enhanced EEG power in the θ range is more easily detected through sparse bump modeling; this phenomenon explains the improved EEG specificity obtained in our previous studies. Conclusions. Sparse bump modeling yields informative features in EEG signal. These features increase the specificity of EEG for diagnosing AD.

  17. Flooding PSA with Plant Specific Operating Experiences of Korean PWRs

    International Nuclear Information System (INIS)

    Choi, Sun Yeong; Yang, Joon Yull

    2006-01-01

    The purpose of this paper is to update the flooding PSA with Korean plant specific operating experience data and the appropriate estimation method for the flooding frequency to improve the PSA quality. The existing flooding PSA used the NPE (Nuclear Power Experience) database up to 1985 for the flooding frequency. They are all USA plant operating experiences. So an upgraded flooding frequency with Korean specific plant operation experience is required. We also propose a method of only using the PWR (Pressurized Water Reactor) data for the flooding frequency estimation in the case of the flooding area in the primary building even though the existing flooding PSA used both PWR and BWR (Boiled Water Reactor) data for all kinds of plant areas. We evaluate the CDF (Core Damage Frequency) with the modified flooding frequency and compare the results with that of the existing flooding PSA method

  18. Nutrition impact symptoms in advanced cancer patients: frequency and specific interventions, a case-control study.

    Science.gov (United States)

    Omlin, Aurelius; Blum, David; Wierecky, Jan; Haile, Sarah R; Ottery, Faith D; Strasser, Florian

    2013-03-01

    Involuntary weight loss (IWL) is frequent in advanced cancer patients causing compromised anticancer treatment outcomes and function. Cancer cachexia is influenced by nutrition impact symptoms (NIS). The aim of this study was to explore the frequency of NIS in advanced patients and to assess specific interventions guided by a 12-item NIS checklist. Consecutive patients from an outpatient nutrition-fatigue clinic completed the NIS checklist. The NIS checklist was developed based on literature review and multiprofessional clinical expert consensus. Chart review was performed to detect defined NIS typical interventions. Oncology outpatients not seen in the nutrition-fatigue clinic were matched for age, sex, and tumor to serve as controls. In 52 nutrition-fatigue clinic patients, a mixed cancer population [IWL in 2 months 5.96 % (mean)], the five most frequent NIS were taste and smell alterations 27 %, constipation 19 %, abdominal pain 14 %, dysphagia 12 %, and epigastric pain 10 %. A statistically significant difference for NIS typical interventions in patients with taste and smell alterations (p = 0.04), constipation (p = 0.01), pain (p = 0.0001), and fatigue (p = 0.0004) were found compared to the control population [mixed cancer, 3.53 % IWL in 2 months (mean)]. NIS are common in advanced cancer patients. The NIS checklist can guide therapeutic nutrition-targeted interventions. The awareness for NIS will likely evoke more research in assessment, impact, and treatment.

  19. Frequency response of electrochemical cells

    Science.gov (United States)

    Thomas, Daniel L.

    1990-01-01

    The main objective was to examine the feasibility of using frequency response techniques (1) as a tool in destructive physical analysis of batteries, particularly for estimating electrode structural parameters such as specific area, porosity, and tortuosity and (2) as a non-destructive testing technique for obtaining information such as state of charge and acceptability for space flight. The phenomena that contribute to the frequency response of an electrode include: (1) double layer capacitance; (2) Faradaic reaction resistance; (3) mass transfer of Warburg impedance; and (4) ohmic solution resistance. Nickel cadmium cells were investigated in solutions of KOH. A significant amount of data was acquired. Quantitative data analysis, using the developed software, is planned for the future.

  20. Brain-computer interface based on intermodulation frequency

    Science.gov (United States)

    Chen, Xiaogang; Chen, Zhikai; Gao, Shangkai; Gao, Xiaorong

    2013-12-01

    Objective. Most recent steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) systems have used a single frequency for each target, so that a large number of targets require a large number of stimulus frequencies and therefore a wider frequency band. However, human beings show good SSVEP responses only in a limited range of frequencies. Furthermore, this issue is especially problematic if the SSVEP-based BCI takes a PC monitor as a stimulator, which is only capable of generating a limited range of frequencies. To mitigate this issue, this study presents an innovative coding method for SSVEP-based BCI by means of intermodulation frequencies. Approach. Simultaneous modulations of stimulus luminance and color at different frequencies were utilized to induce intermodulation frequencies. Luminance flickered at relatively large frequency (10, 12, 15 Hz), while color alternated at low frequency (0.5, 1 Hz). An attractive feature of the proposed method was that it would substantially increase the number of targets at a single flickering frequency by altering color modulated frequencies. Based on this method, the BCI system presented in this study realized eight targets merely using three flickering frequencies. Main results. The online results obtained from 15 subjects (14 healthy and 1 with stroke) revealed that an average classification accuracy of 93.83% and information transfer rate (ITR) of 33.80 bit min-1 were achieved using our proposed SSVEP-based BCI system. Specifically, 5 out of the 15 subjects exhibited an ITR of 40.00 bit min-1 with a classification accuracy of 100%. Significance. These results suggested that intermodulation frequencies could be adopted as steady responses in BCI, for which our system could be used as a practical BCI system.

  1. High-frequency energy in singing and speech

    Science.gov (United States)

    Monson, Brian Bruce

    While human speech and the human voice generate acoustical energy up to (and beyond) 20 kHz, the energy above approximately 5 kHz has been largely neglected. Evidence is accruing that this high-frequency energy contains perceptual information relevant to speech and voice, including percepts of quality, localization, and intelligibility. The present research was an initial step in the long-range goal of characterizing high-frequency energy in singing voice and speech, with particular regard for its perceptual role and its potential for modification during voice and speech production. In this study, a database of high-fidelity recordings of talkers was created and used for a broad acoustical analysis and general characterization of high-frequency energy, as well as specific characterization of phoneme category, voice and speech intensity level, and mode of production (speech versus singing) by high-frequency energy content. Directionality of radiation of high-frequency energy from the mouth was also examined. The recordings were used for perceptual experiments wherein listeners were asked to discriminate between speech and voice samples that differed only in high-frequency energy content. Listeners were also subjected to gender discrimination tasks, mode-of-production discrimination tasks, and transcription tasks with samples of speech and singing that contained only high-frequency content. The combination of these experiments has revealed that (1) human listeners are able to detect very subtle level changes in high-frequency energy, and (2) human listeners are able to extract significant perceptual information from high-frequency energy.

  2. High-resolution mid-IR spectrometer based on frequency upconversion

    DEFF Research Database (Denmark)

    Hu, Qi; Dam, Jeppe Seidelin; Pedersen, Christian

    2012-01-01

    We demonstrate a novel approach for high-resolution spectroscopy based on frequency upconversion and postfiltering by means of a scanning Fabryx2013;Perot interferometer. The system is based on sum-frequency mixing, shifting the spectral content from the mid-infrared to the near-visible region al......-frequency 1064xA0;nm laser. We investigate water vapor emission lines from a butane burner and compare the measured results to model data. The presented method we suggest to be used for real-time monitoring of specific gas lines and reference signals....

  3. Frequency-dependent effects of background noise on subcortical response timing.

    Science.gov (United States)

    Tierney, A; Parbery-Clark, A; Skoe, E; Kraus, N

    2011-12-01

    The addition of background noise to an auditory signal delays brainstem response timing. This effect has been extensively documented using manual peak selection. Peak picking, however, is impractical for large-scale studies of spectrotemporally complex stimuli, and leaves open the question of whether noise-induced delays are frequency-dependent or occur across the frequency spectrum. Here we use an automated, objective method to examine phase shifts between auditory brainstem responses to a speech sound (/da/) presented with and without background noise. We predicted that shifts in neural response timing would also be reflected in frequency-specific phase shifts. Our results indicate that the addition of background noise causes phase shifts across the subcortical response spectrum (70-1000 Hz). However, this noise-induced delay is not uniform such that some frequency bands show greater shifts than others: low-frequency phase shifts (300-500 Hz) are largest during the response to the consonant-vowel formant transition (/d/), while high-frequency shifts (720-1000 Hz) predominate during the response to the steady-state vowel (/a/). Most importantly, phase shifts occurring in specific frequency bands correlate strongly with shifts in the latencies of the predominant peaks in the auditory brainstem response, while phase shifts in other frequency bands do not. This finding confirms the validity of phase shift detection as an objective measure of timing differences and reveals that this method detects noise-induced shifts in timing that may not be captured by traditional peak latency measurements. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Assessment of lightning impact frequency for process equipment

    International Nuclear Information System (INIS)

    Necci, Amos; Antonioni, Giacomo; Cozzani, Valerio; Krausmann, Elisabeth; Borghetti, Alberto; Nucci, Carlo Alberto

    2014-01-01

    Fires and explosions triggered by lightning strikes are among the most frequent Natech scenarios affecting the chemical and process industry. Although lightning hazard is well known, well accepted quantitative procedures to assess the contribution of accidents caused by lightning to industrial risk are still lacking. In the present study, a quantitative methodology for the assessment of the expected frequency of lightning capture by process equipment is presented. A specific model, based on Monte Carlo simulations, was developed to assess the capture frequency of lightning for equipment with a given geometry. The model allows the assessment of lay-out effects and the reduction of the capture probability due to the presence of other structures or equipment items. The results of the Monte Carlo simulations were also used to develop a simplified cell method allowing a straightforward assessment of the lightning impact probability in a quantitative risk assessment framework. The developed approach allows an in-depth analysis of the hazard due to lightning impact by identifying equipment items with the highest expected frequency of lightning impacts in a given lay-out. The model thus supplies useful data to approach the assessment of the quantitative contribution of lightning-triggered accidents to industrial risk. - Highlights: • A specific approach to storage tank lightning impact frequency calculation was developed. • The approach is suitable for the quantitative assessment of industrial risk due to lightning. • The models developed provide lightning capture frequency based on tank geometry. • Lay-out effects due to nearby structures are also accounted. • Capture frequencies may be as high as 10 −1 events/year for standalone unprotected tanks

  5. Non Debye approximation on specific heat of solids

    Science.gov (United States)

    Bhattacharjee, Ruma; Das, Anamika; Sarkar, A.

    2018-05-01

    A simple non Debye frequency spectrum is proposed. The normalized frequency spectrum is compared to that of Debye spectrum. The proposed spectrum, provides a good account of low frequency phonon density of states, which gives a linear temperature variation at low temperature in contrast to Debye T3 law. It has been analyzed that the proposed model provides a good account of excess specific heat for nanostructure solid.

  6. Different Frequencies between Power and Efficiency in Wireless Power Transfer

    OpenAIRE

    Muhammad Afnan, Habibi; Hodaka, Ichijo

    2017-01-01

    Wireless Power Transfer (WPT) has been recognized as a common power transfer method because it transfers electric power without any cable from source to the load. One of the physical principle of WPT is the law of electromagnetic induction, and the WPT system is driven by alternative current power source under specific frequency. The frequency that provides maximum gain between voltages or currents is called resonance frequency. On the other hand, some studies about WPT said that resonance fr...

  7. Stress Recovery Effects of High- and Low-Frequency Amplified Music on Heart Rate Variability.

    Science.gov (United States)

    Nakajima, Yoshie; Tanaka, Naofumi; Mima, Tatsuya; Izumi, Shin-Ichi

    Sounds can induce autonomic responses in listeners. However, the modulatory effect of specific frequency components of music is not fully understood. Here, we examined the role of the frequency component of music on autonomic responses. Specifically, we presented music that had been amplified in the high- or low-frequency domains. Twelve healthy women listened to white noise, a stress-inducing noise, and then one of three versions of a piece of music: original, low-, or high-frequency amplified. To measure autonomic response, we calculated the high-frequency normalized unit (HFnu), low-frequency normalized unit, and the LF/HF ratio from the heart rate using electrocardiography. We defined the stress recovery ratio as the value obtained after participants listened to music following scratching noise, normalized by the value obtained after participants listened to white noise after the stress noise, in terms of the HFnu, low-frequency normalized unit, LF/HF ratio, and heart rate. Results indicated that high-frequency amplified music had the highest HFnu of the three versions. The stress recovery ratio of HFnu under the high-frequency amplified stimulus was significantly larger than that under the low-frequency stimulus. Our results suggest that the high-frequency component of music plays a greater role in stress relief than low-frequency components.

  8. Non-Axisymmetric Oscillation of Acoustically Levitated Water Drops at Specific Frequencies

    International Nuclear Information System (INIS)

    Chang-Le, Shen; Wen-Jun, Xie; Bing-Bo, Wei

    2010-01-01

    A category of non-axisymmetric oscillations of acoustically levitated water drops was observed. These oscillations can be qualitatively described by superposing a sectorial oscillating term upon the initial oblate shape resulting from the effect of acoustic radiation pressure. The oscillation frequencies are around 25 Hz for the 2-lobed mode and exactly 50 Hz for the 3- and 4-lobed modes. These oscillations were excited by the disturbance from the power supply. For the same water drop, higher mode oscillations were observed with more oblate initial shape, indicating that the eigenfrequencies of these non-axisymmetric oscillations decrease with increasing initial distortion. The maximum velocity and acceleration within the oscillating drop can attain 0.3m·s −1 and 98.7m·s −2 respectively, resulting in strong fluid convection and enhanced heat and mass transfer. (condensed matter: structure, mechanical and thermal properties)

  9. Magnetic nanoparticles colourization by a mixing-frequency method

    International Nuclear Information System (INIS)

    Tu, Liang; Wu, Kai; Klein, Todd; Wang, Jian-Ping

    2014-01-01

    Brownian and Néel relaxation of magnetic nanoparticles (MNPs) can be characterized by a highly sensitive mixing-frequency method using a search-coil based detection system. The unique magnetic properties of MNPs have been used for biomarkers detection. In this paper, we present a theory and implement an experimental detection scheme using the mixing-frequency method to identify different MNPs simultaneously. A low-frequency sinusoidal magnetic field is applied to saturate the MNPs periodically. A high-frequency sinusoidal magnetic field is then applied to generate mixing-frequency signals that are highly specific to the magnetization of MNPs. The spectra of each MNP can be defined as the complex magnetization of the MNPs over the field frequency. The magnetic spectra of various MNPs and magnetic beads have been characterized and compared. The differences between the MNPs spectra enable us to identify the individual MNPs at the same time. A test has been done to verify the ratio of two different MNPs in mixed samples based on the proposed theory. The experimental results show that the mixing-frequency method is a promising method for MNPs colourization. (paper)

  10. Risk-informed approach in US-APWR technical specifications

    International Nuclear Information System (INIS)

    Saji, Etsuro; Tanaka, Futoshi; Kuroiwa, Katsuya; Kawai, Katsunori

    2009-01-01

    The Risk-Managed Technical Specifications and the Surveillance Frequency Control Program have been adopted in the US-APWR Technical Specifications. These risk-informed approaches are unique among the technical specifications for the advanced light water reactor designs adopted by planned nuclear power stations in the United States. (author)

  11. An ultra-stable optical frequency reference for space

    Science.gov (United States)

    Schuldt, T.; Döringshoff, K.; Kovalchuk, E.; Pahl, J.; Gohlke, M.; Weise, D.; Johann, U.; Peters, A.; Braxmaier, C.

    2017-11-01

    We realized ultra-stable optical frequency references on elegant breadboard (EBB) and engineering model (EM) level utilizing Doppler-free spectroscopy of molecular iodine near 532nm. A frequency stability of about 1•10-14 at an integration time of 1 s and below 5•10-15 at integration times between 10 s and 100 s was achieved. These values are comparable to the currently best laboratory setups. Both setups use a baseplate made of glass material where the optical components are joint using a specific assembly-integration technology. Compared to the EBB setup, the EM setup is further developed with respect to compactness and mechanical and thermal stability. The EM setup uses a baseplate made of fused silica with dimensions of 380 x 180 x 40 mm3 and a specifically designed 100 x 100 x 30 mm3 rectangular iodine cell in nine-pass configuration with a specific robust cold finger design. The EM setup was subjected to thermal cycling and vibrational testing. Applications of such an optical frequency reference in space can be found in fundamental physics, geoscience, Earth observation, and navigation & ranging. One example is the proposed mSTAR (mini SpaceTime Asymmetry Research) mission, dedicated to perform a Kennedy-Thorndike experiment on a satellite in a sunsynchronous low-Earth orbit. By comparing an iodine standard to a cavity-based frequency reference and integration over 2 year mission lifetime, the Kennedy-Thorndike coefficient will be determined with up to two orders of magnitude higher accuracy than the current best ground experiment. In a current study, the compatibility of the payload with the SaudiSat-4 host vehicle is investigated.

  12. Specific-locus mutation frequencies in mouse stem-cell spermatogonia at very low radiation dose rates, and their use in the estimation of genetic hazards of radiation in man

    International Nuclear Information System (INIS)

    Russell, W.L.; Kelly, E.M.

    1982-01-01

    Experiments were undertaken to augment the information on the lowest radiation dose rates feasible for scoring transmitted induced mutations detected by the specific-locus method in the mouse. This is the type of information most suitable for estimating genetic hazards of radiation in man. The results also aid in resolving conflicting possibilities about the relationship between mutation frequency and radiation dose at low dose rates

  13. Spatial Frequency Discrimination : Effects of Age, Reward, and Practice

    OpenAIRE

    van den Boomen, Carlijn; Peters, Judith Carolien

    2017-01-01

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effec...

  14. Negative feedback governs gonadotrope frequency-decoding of gonadotropin releasing hormone pulse-frequency.

    Directory of Open Access Journals (Sweden)

    Stefan Lim

    Full Text Available The synthesis of the gonadotropin subunits is directed by pulsatile gonadotropin-releasing hormone (GnRH from the hypothalamus, with the frequency of GnRH pulses governing the differential expression of the common alpha-subunit, luteinizing hormone beta-subunit (LHbeta and follicle-stimulating hormone beta-subunit (FSHbeta. Three mitogen-activated protein kinases, (MAPKs, ERK1/2, JNK and p38, contribute uniquely and combinatorially to the expression of each of these subunit genes. In this study, using both experimental and computational methods, we found that dual specificity phosphatase regulation of the activity of the three MAPKs through negative feedback is required, and forms the basis for decoding the frequency of pulsatile GnRH. A fourth MAPK, ERK5, was shown also to be activated by GnRH. ERK5 was found to stimulate FSHbeta promoter activity and to increase FSHbeta mRNA levels, as well as enhancing its preference for low GnRH pulse frequencies. The latter is achieved through boosting the ultrasensitive behavior of FSHbeta gene expression by increasing the number of MAPK dependencies, and through modulating the feedforward effects of JNK activation on the GnRH receptor (GnRH-R. Our findings contribute to understanding the role of changing GnRH pulse-frequency in controlling transcription of the pituitary gonadotropins, which comprises a crucial aspect in regulating reproduction. Pulsatile stimuli and oscillating signals are integral to many biological processes, and elucidation of the mechanisms through which the pulsatility is decoded explains how the same stimulant can lead to various outcomes in a single cell.

  15. Algorithmic Finance and (Limits to Governmentality: On Foucault and High-Frequency Trading

    Directory of Open Access Journals (Sweden)

    Christian Borch

    2017-09-01

    Full Text Available In this essay I discuss algorithmic finance, specifically the use of fully automated trading, including high-frequency trading, in the light of Michel Foucault's notion of governmentality. I argue that a governmentality perspective offers a fruitful way of understanding particular aspects of high-frequency trading, such as how algorithms are designed to govern other market participants' anticipations of market dynamics. However, I also argue that, to fully understand the realm of algorithmic finance and high-frequency trading, it is important to supplement a governmentality approach with an analytical lexicon which is not primarily centred on productive forms of power. Specifically, I suggest that, according to media discourses on high-frequency trading, algorithmic finance often works in ways that are better grasped through, e.g. Elias Canetti's work on predatory power and Roger Caillois's work on mimesis.

  16. Relative frequency and estimated minimal frequency of Lysosomal Storage Diseases in Brazil: Report from a Reference Laboratory

    Directory of Open Access Journals (Sweden)

    Roberto Giugliani

    2017-03-01

    Full Text Available Abstract Lysosomal storage diseases (LSDs comprise a heterogeneous group of more than 50 genetic conditions of inborn errors of metabolism (IEM caused by a defect in lysosomal function. Although there are screening tests for some of these conditions, diagnosis usually depends on specific enzyme assays, which are only available in a few laboratories around the world. A pioneer facility for the diagnosis of IEM and LSDs was established in the South of Brazil in 1982 and has served as a reference service since then. Over the past 34 years, samples from 72,797 patients were referred for investigation of IEM, and 3,211 were confirmed as having an LSD (4.41%, or 1 in 22, with 3,099 of these patients originating from Brazil. The rate of diagnosis has increased over time, in part due to the creation of diagnostic networks involving a large number of Brazilian services. These cases, referred from Brazilian regions, provide insight about the relative frequency of LSDs in the country. The large amount of data available allows for the estimation of the minimal frequency of specific LSDs in Brazil. The reported data could help to plan health care policies, as there are specific therapies available for most of the cases diagnosed.

  17. Frequency and amplitude stabilization in MEMS and NEMS oscillators

    Science.gov (United States)

    Chen, Changyao; Lopez, Omar Daniel; Czaplewski, David A.

    2017-06-14

    This invention comprises a nonlinear micro- and nano-mechanical resonator that can maintain frequency of operation and amplitude of operation for a period of time after all external power has been removed from the device. Utilizing specific nonlinear dynamics of the micromechanical resonator, mechanical energy at low frequencies can be input and stored in higher frequencies modes, thus using the multiple degrees of freedom of the resonator to extend its energy storage capacity. Furthermore, the energy stored in multiple vibrational modes can be used to maintain the resonator oscillating for a fixed period of time, even without an external power supply. This is the first demonstration of an "autonomous" frequency source that can maintain a constant frequency and vibrating amplitude when no external power is provided, making it ideal for applications requiring an oscillator in low power, or limited and intermittent power supplies.

  18. Frequency-Dependent Blanking with Digital Linear Chirp Waveform Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Andrews, John M. [General Atomics Aeronautical Systems, Inc., San Diego, CA (United States)

    2014-07-01

    Wideband radar systems, especially those that operate at lower frequencies such as VHF and UHF, are often restricted from transmitting within or across specific frequency bands in order to prevent interference to other spectrum users. Herein we describe techniques for notching the transmitted spectrum of a generated and transmitted radar waveform. The notches are fully programmable as to their location, and techniques are given that control the characteristics of the notches.

  19. Investigating Effects of Nano- to Micro-Ampere Alternating Current Stimulation on Trichophyton rubrum Growth.

    Science.gov (United States)

    Kwon, Dong Rak; Kwon, Hyunjung; Lee, Woo Ram; Park, Joonsoo

    2016-10-01

    Fungi are eukaryotic microorganisms including yeast and molds. Many studies have focused on modifying bacterial growth, but few on fungal growth. Microcurrent electricity may stimulate fungal growth. This study aims to investigate effects of microcurrent electric stimulation on Trichophyton rubrum growth. Standard-sized inoculums of T. rubrum derived from a spore suspension were applied to potato dextrose cornmeal agar (PDACC) plates, gently withdrawn with a sterile pipette, and were applied to twelve PDACC plates with a sterile spreader. Twelve Petri dishes were divided into four groups. The given amperage of electric current was 500 nA, 2 µA, and 4 µA in groups A, B, and C, respectively. No electric current was given in group D. In the first 48 hours, colonies only appeared in groups A and B (500 nA and 2 µA exposure). Colonies in group A (500 nA) were denser. Group C (4 µA) plates showed a barely visible film of fungus after 96 hours of incubation. Fungal growth became visible after 144 hours in the control group. Lower intensities of electric current caused faster fungal growth within the amperage range used in this study. Based on these results, further studies with a larger sample size, various fungal species, and various intensities of electric stimulation should be conducted.

  20. Effects of dendritic load on the firing frequency of oscillating neurons.

    Science.gov (United States)

    Schwemmer, Michael A; Lewis, Timothy J

    2011-03-01

    We study the effects of passive dendritic properties on the dynamics of neuronal oscillators. We find that the addition of a passive dendrite can sometimes have counterintuitive effects on firing frequency. Specifically, the addition of a hyperpolarized passive dendritic load can either increase, decrease, or have negligible effects on firing frequency. We use the theory of weak coupling to derive phase equations for "ball-and-stick" model neurons and two-compartment model neurons. We then develop a framework for understanding how the addition of passive dendrites modulates the frequency of neuronal oscillators. We show that the average value of the neuronal oscillator's phase response curves measures the sensitivity of the neuron's firing rate to the dendritic load, including whether the addition of the dendrite causes an increase or decrease in firing frequency. We interpret this finding in terms of to the slope of the neuronal oscillator's frequency-applied current curve. We also show that equivalent results exist for constant and noisy point-source input to the dendrite. We note that the results are not specific to neurons but are applicable to any oscillator subject to a passive load.

  1. Low frequency phase signal measurement with high frequency squeezing

    OpenAIRE

    Zhai, Zehui; Gao, Jiangrui

    2011-01-01

    We calculate the utility of high-frequency squeezed-state enhanced two-frequency interferometry for low-frequency phase measurement. To use the high-frequency sidebands of the squeezed light, a two-frequency intense laser is used in the interferometry instead of a single-frequency laser as usual. We find that the readout signal can be contaminated by the high-frequency phase vibration, but this is easy to check and avoid. A proof-of-principle experiment is in the reach of modern quantum optic...

  2. Flextensional fiber Bragg grating-based accelerometer for low frequency vibration measurement

    Institute of Scientific and Technical Information of China (English)

    Jinghua Zhang; Xueguang Qiao; Manli Hu; Zhongyao Feng; Hong Gao; Yang Yang; Rui Zhou

    2011-01-01

    @@ The intelligent structural health monitoring method,which uses a fiber Bragg grating(FBG)sensor,is a new approach in the field of civil engineering.However,it lacks a reliable FBG-based accelerometer for taking structural low frequency vibration measurements.In this letter,a flextensional FBG-based accelerometer is proposed and demonstrated.The experimental results indicate that the natural frequency of the developed accelerometer is 16.7 Hz,with a high sensitivity of 410.7 pm/g.In addition,it has a broad and flat response over low frequencies ranging from 1 to 10 Hz.The natural frequency and sensitivity of the accelerometer can be tuned by adding mass to tailor the sensor performance to specific applications.Experimental results are presented to demonstrate the good performance of the proposed FBG-based accelerometer.These results show that the proposed accelerometer is satisfactory for low frequency vibration measurements.%The intelligent structural health monitoring method, which uses a fiber Bragg grating {FBG} sensor, ie a new approach in the field of civil engineering. However, it lacks a reliable FBG-based accelerometer for taking structural low frequency vibration measurements. In this letter, a flextensional FBG-based accelerometer is proposed and demonstrated. The experimental results indicate that the natural frequency of the developed accelerometer is 16.7 Hz, with a high sensitivity of 410.7 pm/g. In addition, it has a broad and flat response over low frequencies ranging from 1 to 10 Hz. The natural frequency and sensitivity of the accelerometer can be tuned by adding mass to tailor the sensor performance to specific applications. Experimental results are presented to demonstrate the good performance of the proposed FBG-based accelerometer. These results show that the proposed accelerometer is satisfactory for low frequency vibration measurements.

  3. Frequency analysis for the thermal hydraulic characterization of a natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Walmir M.; Macedo, Luiz A.; Sabundjian, Gaiane; Andrade, Delvonei A.; Umbehaun, Pedro E.; Conti, Thadeu N.; Mesquita, Roberto N.; Masotti, Paulo H.; Angelo, Gabriel, E-mail: wmtorres@ipen.b, E-mail: lamacedo@ipen.b, E-mail: gdjian@ipen.b, E-mail: delvonei@ipen.b, E-mail: umbehaun@ipen.b, E-mail: tnconti@ipen.b, E-mail: , E-mail: rnavarro@ipen.b, E-mail: pmasotti@ipen.b, E-mail: gabriel.angelo@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    This paper presents the frequency analysis studies of the pressure signals from an experimental natural circulation circuit during a heating process. The main objective is to identify the characteristic frequencies of this process using fast Fourier transform. Video images are used to associate these frequencies to the observed phenomenology in the circuit during the process. Sub-cooled and saturated flow boiling, heaters vibrations, overall circuit vibrations, chugging and geysering were observed. Each phenomenon has its specific frequency associated. Some phenomena and their frequencies must be avoided or attenuated since they can cause damages to the natural circulation circuit and its components. Special operation procedures and devices can be developed to avoid these undesirable frequencies. (author)

  4. Frequency analysis for the thermal hydraulic characterization of a natural circulation circuit

    International Nuclear Information System (INIS)

    Torres, Walmir M.; Macedo, Luiz A.; Sabundjian, Gaiane; Andrade, Delvonei A.; Umbehaun, Pedro E.; Conti, Thadeu N.; Mesquita, Roberto N.; Masotti, Paulo H.; Angelo, Gabriel

    2011-01-01

    This paper presents the frequency analysis studies of the pressure signals from an experimental natural circulation circuit during a heating process. The main objective is to identify the characteristic frequencies of this process using fast Fourier transform. Video images are used to associate these frequencies to the observed phenomenology in the circuit during the process. Sub-cooled and saturated flow boiling, heaters vibrations, overall circuit vibrations, chugging and geysering were observed. Each phenomenon has its specific frequency associated. Some phenomena and their frequencies must be avoided or attenuated since they can cause damages to the natural circulation circuit and its components. Special operation procedures and devices can be developed to avoid these undesirable frequencies. (author)

  5. Massage Therapy and Frequency of Chronic Tension Headaches

    Science.gov (United States)

    Quinn, Christopher; Chandler, Clint; Moraska, Albert

    2002-01-01

    Objectives. The effect of massage therapy on chronic nonmigraine headache was investigated. Methods. Chronic tension headache sufferers received structured massage therapy treatment directed toward neck and shoulder muscles. Headache frequency, duration, and intensity were recorded and compared with baseline measures. Results. Compared with baseline values, headache frequency was significantly reduced within the first week of the massage protocol. The reduction of headache frequency continued for the remainder of the study (P = .009). The duration of headaches tended to decrease during the massage treatment period (P = .058). Headache intensity was unaffected by massage (P = .19). Conclusions. The muscle-specific massage therapy technique used in this study has the potential to be a functional, nonpharmacological intervention for reducing the incidence of chronic tension headache. PMID:12356617

  6. Engineering Inertial and Primary-Frequency Response for Distributed Energy Resources: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dall-Anese, Emiliano [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Guggilam, Swaroop [University of Minnesota; Dhople, Sairaj V [University of Minnesota; Chen, Yu C [University of British Columbia; Zhao, Changhong [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-19

    We propose a framework to engineer synthetic-inertia and droop-control parameters for distributed energy resources (DERs) so that the system frequency in a network composed of DERs and synchronous generators conforms to prescribed transient and steady-state performance specifications. Our approach is grounded in a second-order lumped-parameter model that captures the dynamics of synchronous generators and frequency-responsive DERs endowed with inertial and droop control. A key feature of this reduced-order model is that its parameters can be related to those of the originating higher-order dynamical model. This allows one to systematically design the DER inertial and droop-control coefficients leveraging classical frequency-domain response characteristics of second-order systems. Time-domain simulations validate the accuracy of the model-reduction method and demonstrate how DER controllers can be designed to meet steady-state-regulation and transient-performance specifications.

  7. Sensory memory consolidation observed: Increased specificity of detail over days

    Science.gov (United States)

    Weinberger, Norman M.; Miasnikov, Alexandre A.; Chen, Jemmy C.

    2010-01-01

    Memories are usually multidimensional, including contents such as sensory details, motivational state and emotional overtones. Memory contents generally change over time, most often reported as a loss in the specificity of detail. To study the temporal changes in the sensory contents of associative memory without motivational and emotional contents, we induced memory for acoustic frequency by pairing a tone with stimulation of the cholinergic nucleus basalis. Adult male rats were first tested for behavioral responses (disruption of ongoing respiration) to tones (1–15 kHz), yielding pre-training behavioral frequency generalization gradients (BFGG). They next received three days of training consisting of a conditioned stimulus (CS) tone (8.00 kHz, 70 dB, 2 s) either Paired (n = 5) or Unpaired (n = 5) with weak electrical stimulation (~48 μA) of the nucleus basalis (100 Hz, 0.2 s, co-terminating with CS offset). Testing for behavioral memory was performed by obtaining post-training BFGGs at two intervals, 24 and 96 h after training. At 24 h post-training, the Paired group exhibited associative behavioral memory manifested by significantly larger responses to tone than the Unpaired group. However, they exhibited no specificity in memory for the frequency of the tonal CS, as indexed by a flat BFGG. In contrast, after 96 h post-training the Paired group did exhibit specificity of memory as revealed by tuned BFGGs with a peak at the CS-band of frequencies. This increased detail of memory developed due to a loss of response to lower and higher frequency side-bands, without any change in the absolute magnitude of response to CS-band frequencies. These findings indicate that the sensory contents of associative memory can be revealed to become more specific, through temporal consolidation in the absence of non-sensory factors such as motivation and emotion. PMID:19038352

  8. Sensory memory consolidation observed: increased specificity of detail over days.

    Science.gov (United States)

    Weinberger, Norman M; Miasnikov, Alexandre A; Chen, Jemmy C

    2009-03-01

    Memories are usually multidimensional, including contents such as sensory details, motivational state and emotional overtones. Memory contents generally change over time, most often reported as a loss in the specificity of detail. To study the temporal changes in the sensory contents of associative memory without motivational and emotional contents, we induced memory for acoustic frequency by pairing a tone with stimulation of the cholinergic nucleus basalis. Adult male rats were first tested for behavioral responses (disruption of ongoing respiration) to tones (1-15 kHz), yielding pre-training behavioral frequency generalization gradients (BFGG). They next received three days of training consisting of a conditioned stimulus (CS) tone (8.00 kHz, 70 dB, 2 s) either Paired (n=5) or Unpaired (n=5) with weak electrical stimulation (approximately 48 microA) of the nucleus basalis (100 Hz, 0.2 s, co-terminating with CS offset). Testing for behavioral memory was performed by obtaining post-training BFGGs at two intervals, 24 and 96 h after training. At 24 h post-training, the Paired group exhibited associative behavioral memory manifested by significantly larger responses to tone than the Unpaired group. However, they exhibited no specificity in memory for the frequency of the tonal CS, as indexed by a flat BFGG. In contrast, after 96 h post-training the Paired group did exhibit specificity of memory as revealed by tuned BFGGs with a peak at the CS-band of frequencies. This increased detail of memory developed due to a loss of response to lower and higher frequency side-bands, without any change in the absolute magnitude of response to CS-band frequencies. These findings indicate that the sensory contents of associative memory can be revealed to become more specific, through temporal consolidation in the absence of non-sensory factors such as motivation and emotion.

  9. Influence of modulation frequency in rubidium cell frequency standards

    Science.gov (United States)

    Audoin, C.; Viennet, J.; Cyr, N.; Vanier, J.

    1983-01-01

    The error signal which is used to control the frequency of the quartz crystal oscillator of a passive rubidium cell frequency standard is considered. The value of the slope of this signal, for an interrogation frequency close to the atomic transition frequency is calculated and measured for various phase (or frequency) modulation waveforms, and for several values of the modulation frequency. A theoretical analysis is made using a model which applies to a system in which the optical pumping rate, the relaxation rates and the RF field are homogeneous. Results are given for sine-wave phase modulation, square-wave frequency modulation and square-wave phase modulation. The influence of the modulation frequency on the slope of the error signal is specified. It is shown that the modulation frequency can be chosen as large as twice the non-saturated full-width at half-maximum without a drastic loss of the sensitivity to an offset of the interrogation frequency from center line, provided that the power saturation factor and the amplitude of modulation are properly adjusted.

  10. Letter Frequency Analysis of Lithuanian and Other Languages Using the Latin Alphabet

    Directory of Open Access Journals (Sweden)

    Gintautas Grigas

    2015-12-01

    Full Text Available It is important to evaluate specificities of alphabets, particularly the letter frequencies while designing keyboards, analyzing texts, designing games based on alphabets, and doing some text mining. In order to adequately compare lettter frequences of Lithuanian language to other languages in the Internet space, Wikipedia source was selected which content is common to different languages. The method of letter frequency jumps is used. The main attention is paid to the analysis of letter frequencies at the boundary between native letters and foreign letters used in Lithuanian and other languages.

  11. Scientific applications of frequency-stabilized laser technology in space

    Science.gov (United States)

    Schumaker, Bonny L.

    1990-01-01

    A synoptic investigation of the uses of frequency-stabilized lasers for scientific applications in space is presented. It begins by summarizing properties of lasers, characterizing their frequency stability, and describing limitations and techniques to achieve certain levels of frequency stability. Limits to precision set by laser frequency stability for various kinds of measurements are investigated and compared with other sources of error. These other sources include photon-counting statistics, scattered laser light, fluctuations in laser power, and intensity distribution across the beam, propagation effects, mechanical and thermal noise, and radiation pressure. Methods are explored to improve the sensitivity of laser-based interferometric and range-rate measurements. Several specific types of science experiments that rely on highly precise measurements made with lasers are analyzed, and anticipated errors and overall performance are discussed. Qualitative descriptions are given of a number of other possible science applications involving frequency-stabilized lasers and related laser technology in space. These applications will warrant more careful analysis as technology develops.

  12. The low-frequency encoding disadvantage: Word frequency affects processing demands.

    Science.gov (United States)

    Diana, Rachel A; Reder, Lynne M

    2006-07-01

    Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g., L. M. Reder et al., 2000). When tasks other than recognition, such as recall, cued recall, or associative recognition, are used, the effects seem to contradict a low-frequency advantage in memory. Four experiments are presented to support the claim that in addition to the advantage of low-frequency words at retrieval, there is a low-frequency disadvantage during encoding. That is, low-frequency words require more processing resources to be encoded episodically than high-frequency words. Under encoding conditions in which processing resources are limited, low-frequency words show a larger decrement in recognition than high-frequency words. Also, studying items (pictures and words of varying frequencies) along with low-frequency words reduces performance for those stimuli. Copyright 2006 APA, all rights reserved.

  13. Low power very high frequency resonant converter with high step down ratio

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    This paper presents the design of a resonant converter with a switching frequency in the very high frequency range (30-300MHz), a large step down ratio and low output power. This gives the designed converters specifications which are far from previous results. The class E inverter and rectifier...

  14. Frequency Stepped Pulse Train Modulated Wind Sensing Lidar

    DEFF Research Database (Denmark)

    Olesen, Anders Sig; Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2011-01-01

    of frequency shifts corresponding to a specific distance. The spatial resolution depends on the repetition rate of the pulses in the pulse train. Directional wind measurements are shown and compared to a CW lidar measurement. The carrier to noise ratio of the FSPT lidar compared to a CW lidar is discussed......In this paper a wind sensing lidar utilizing a Frequency Stepped Pulse Train (FSPT) is demonstrated. One of the advantages in the FSTP lidar is that it enables direct measurement of wind speed as a function of distance from the lidar. Theoretically the FSPT lidar continuously produces measurements...... as is the case with a CW lidar, but at the same time with a spatial resolution, and without the range ambiguity originating from e.g. clouds. The FSPT lidar utilizes a frequency sweeping source for generation of the FSPT. The source generates a pulse train where each pulse has an optical carrier frequency...

  15. Collective frequency variation in network synchronization and reverse PageRank.

    Science.gov (United States)

    Skardal, Per Sebastian; Taylor, Dane; Sun, Jie; Arenas, Alex

    2016-04-01

    A wide range of natural and engineered phenomena rely on large networks of interacting units to reach a dynamical consensus state where the system collectively operates. Here we study the dynamics of self-organizing systems and show that for generic directed networks the collective frequency of the ensemble is not the same as the mean of the individuals' natural frequencies. Specifically, we show that the collective frequency equals a weighted average of the natural frequencies, where the weights are given by an outflow centrality measure that is equivalent to a reverse PageRank centrality. Our findings uncover an intricate dependence of the collective frequency on both the structural directedness and dynamical heterogeneity of the network, and also reveal an unexplored connection between synchronization and PageRank, which opens the possibility of applying PageRank optimization to synchronization. Finally, we demonstrate the presence of collective frequency variation in real-world networks by considering the UK and Scandinavian power grids.

  16. Collective frequency variation in network synchronization and reverse PageRank

    Science.gov (United States)

    Skardal, Per Sebastian; Taylor, Dane; Sun, Jie; Arenas, Alex

    2016-04-01

    A wide range of natural and engineered phenomena rely on large networks of interacting units to reach a dynamical consensus state where the system collectively operates. Here we study the dynamics of self-organizing systems and show that for generic directed networks the collective frequency of the ensemble is not the same as the mean of the individuals' natural frequencies. Specifically, we show that the collective frequency equals a weighted average of the natural frequencies, where the weights are given by an outflow centrality measure that is equivalent to a reverse PageRank centrality. Our findings uncover an intricate dependence of the collective frequency on both the structural directedness and dynamical heterogeneity of the network, and also reveal an unexplored connection between synchronization and PageRank, which opens the possibility of applying PageRank optimization to synchronization. Finally, we demonstrate the presence of collective frequency variation in real-world networks by considering the UK and Scandinavian power grids.

  17. Multiscale energy reallocation during low-frequency steady-state brain response.

    Science.gov (United States)

    Wang, Yifeng; Chen, Wang; Ye, Liangkai; Biswal, Bharat B; Yang, Xuezhi; Zou, Qijun; Yang, Pu; Yang, Qi; Wang, Xinqi; Cui, Qian; Duan, Xujun; Liao, Wei; Chen, Huafu

    2018-05-01

    Traditional task-evoked brain activations are based on detection and estimation of signal change from the mean signal. By contrast, the low-frequency steady-state brain response (lfSSBR) reflects frequency-tagging activity at the fundamental frequency of the task presentation and its harmonics. Compared to the activity at these resonant frequencies, brain responses at nonresonant frequencies are largely unknown. Additionally, because the lfSSBR is defined by power change, we hypothesize using Parseval's theorem that the power change reflects brain signal variability rather than the change of mean signal. Using a face recognition task, we observed power increase at the fundamental frequency (0.05 Hz) and two harmonics (0.1 and 0.15 Hz) and power decrease within the infra-slow frequency band ( .955) of their spatial distribution and brain-behavior relationship at all frequency bands. Additionally, the reallocation of finite energy was observed across various brain regions and frequency bands, forming a particular spatiotemporal pattern. Overall, results from this study strongly suggest that frequency-specific power and variability may measure the same underlying brain activity and that these results may shed light on different mechanisms between lfSSBR and brain activation, and spatiotemporal characteristics of energy reallocation induced by cognitive tasks. © 2018 Wiley Periodicals, Inc.

  18. Carbon financial markets: A time-frequency analysis of CO2 prices

    Science.gov (United States)

    Sousa, Rita; Aguiar-Conraria, Luís; Soares, Maria Joana

    2014-11-01

    We characterize the interrelation of CO2 prices with energy prices (electricity, gas and coal), and with economic activity. Previous studies have relied on time-domain techniques, such as Vector Auto-Regressions. In this study, we use multivariate wavelet analysis, which operates in the time-frequency domain. Wavelet analysis provides convenient tools to distinguish relations at particular frequencies and at particular time horizons. Our empirical approach has the potential to identify relations getting stronger and then disappearing over specific time intervals and frequencies. We are able to examine the coherency of these variables and lead-lag relations at different frequencies for the time periods in focus.

  19. Computing Instantaneous Frequency by normalizing Hilbert Transform

    Science.gov (United States)

    Huang, Norden E.

    2005-05-31

    This invention presents Normalized Amplitude Hilbert Transform (NAHT) and Normalized Hilbert Transform(NHT), both of which are new methods for computing Instantaneous Frequency. This method is designed specifically to circumvent the limitation set by the Bedorsian and Nuttal Theorems, and to provide a sharp local measure of error when the quadrature and the Hilbert Transform do not agree. Motivation for this method is that straightforward application of the Hilbert Transform followed by taking the derivative of the phase-angle as the Instantaneous Frequency (IF) leads to a common mistake made up to this date. In order to make the Hilbert Transform method work, the data has to obey certain restrictions.

  20. Frequency noise in frequency swept fiber laser

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-01-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto......- optical modulators and forward propagating Brillouin scattering appear in the spectrum. © 2013 Optical Society of America....

  1. Intrinsic frequency biases and profiles across human cortex.

    Science.gov (United States)

    Mellem, Monika S; Wohltjen, Sophie; Gotts, Stephen J; Ghuman, Avniel Singh; Martin, Alex

    2017-11-01

    Recent findings in monkeys suggest that intrinsic periodic spiking activity in selective cortical areas occurs at timescales that follow a sensory or lower order-to-higher order processing hierarchy (Murray JD, Bernacchia A, Freedman DJ, Romo R, Wallis JD, Cai X, Padoa-Schioppa C, Pasternak T, Seo H, Lee D, Wang XJ. Nat Neurosci 17: 1661-1663, 2014). It has not yet been fully explored if a similar timescale hierarchy is present in humans. Additionally, these measures in the monkey studies have not addressed findings that rhythmic activity within a brain area can occur at multiple frequencies. In this study we investigate in humans if regions may be biased toward particular frequencies of intrinsic activity and if a full cortical mapping still reveals an organization that follows this hierarchy. We examined the spectral power in multiple frequency bands (0.5-150 Hz) from task-independent data using magnetoencephalography (MEG). We compared standardized power across bands to find regional frequency biases. Our results demonstrate a mix of lower and higher frequency biases across sensory and higher order regions. Thus they suggest a more complex cortical organization that does not simply follow this hierarchy. Additionally, some regions do not display a bias for a single band, and a data-driven clustering analysis reveals a regional organization with high standardized power in multiple bands. Specifically, theta and beta are both high in dorsal frontal cortex, whereas delta and gamma are high in ventral frontal cortex and temporal cortex. Occipital and parietal regions are biased more narrowly toward alpha power, and ventral temporal lobe displays specific biases toward gamma. Thus intrinsic rhythmic neural activity displays a regional organization but one that is not necessarily hierarchical. NEW & NOTEWORTHY The organization of rhythmic neural activity is not well understood. Whereas it has been postulated that rhythms are organized in a hierarchical manner across

  2. Transport accident frequency data, their sources and their application in risk assessment

    International Nuclear Information System (INIS)

    Appleton, P.R.

    1988-08-01

    Base transport accident frequency data and sources of these data are presented. Both generic information and rates specific to particular routes or packages are included. Strong packages, such as those containing significant quantities of radioactive materials, will survive most of the accidents represented by these base frequencies without a containment breach. The association of severity probability distributions with a base frequency, and package and contents response, leading to the quantification of release frequency and magnitude, are often more important in risk assessment than the base frequency itself. This paper therefore also includes brief comments on techniques adopted to utilize the base frequencies. This paper reports an accident frequency data survey undertaken at the end of 1986. It has not been updated to take account of work published between January 1987 and the Report publication date. (author)

  3. Correcting length-frequency distributions for imperfect detection

    Science.gov (United States)

    Breton, André R.; Hawkins, John A.; Winkelman, Dana L.

    2013-01-01

    Sampling gear selects for specific sizes of fish, which may bias length-frequency distributions that are commonly used to assess population size structure, recruitment patterns, growth, and survival. To properly correct for sampling biases caused by gear and other sources, length-frequency distributions need to be corrected for imperfect detection. We describe a method for adjusting length-frequency distributions when capture and recapture probabilities are a function of fish length, temporal variation, and capture history. The method is applied to a study involving the removal of Smallmouth Bass Micropterus dolomieu by boat electrofishing from a 38.6-km reach on the Yampa River, Colorado. Smallmouth Bass longer than 100 mm were marked and released alive from 2005 to 2010 on one or more electrofishing passes and removed on all other passes from the population. Using the Huggins mark–recapture model, we detected a significant effect of fish total length, previous capture history (behavior), year, pass, year×behavior, and year×pass on capture and recapture probabilities. We demonstrate how to partition the Huggins estimate of abundance into length frequencies to correct for these effects. Uncorrected length frequencies of fish removed from Little Yampa Canyon were negatively biased in every year by as much as 88% relative to mark–recapture estimates for the smallest length-class in our analysis (100–110 mm). Bias declined but remained high even for adult length-classes (≥200 mm). The pattern of bias across length-classes was variable across years. The percentage of unadjusted counts that were below the lower 95% confidence interval from our adjusted length-frequency estimates were 95, 89, 84, 78, 81, and 92% from 2005 to 2010, respectively. Length-frequency distributions are widely used in fisheries science and management. Our simple method for correcting length-frequency estimates for imperfect detection could be widely applied when mark–recapture data

  4. Precipitation Depth-Duration-Frequency Analysis for the Nevada National Security Site and Surrounding Areas

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Li [Desert Research Inst. (DRI), Las Vegas, NV (United States). Division of Hydrologic Sciences; Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States). Division of Hydrologic Sciences

    2016-08-01

    Accurate precipitation frequency data are important for Environmental Management Soils Activities on the Nevada National Security Site (NNSS). These data are important for environmental assessments performed for regulatory closure of Soils Corrective Action Unit (CAU) Sites, as well as engineering mitigation designs and post-closure monitoring strategies to assess and minimize potential contaminant migration from Soils CAU Sites. Although the National Oceanic and Atmospheric Administration (NOAA) Atlas 14 (Bonnin et al., 2011) provides precipitation frequency data for the NNSS area, the NNSS-specific observed precipitation data were not consistent with the NOAA Atlas 14 predicted data. This is primarily due to the NOAA Atlas 14 products being produced from analyses without including the approximately 30 NNSS precipitation gage records, several of which approach or exceed 50 year of record. Therefore, a study of precipitation frequency that incorporated the NNSS precipitation gage records into the NOAA Atlas 14 dataset, was performed specifically for the NNSS to derive more accurate site-specific precipitation data products. Precipitation frequency information, such as the depth-duration-frequency (DDF) relationships, are required to generate synthetic standard design storm hydrographs and assess actual precipitation events. In this study, the actual long-term NNSS precipitation gage records, some of which are the longest gage records in southern and central Nevada, were analyzed to allow for more accurate precipitation DDF estimates to be developed for the NNSS. Gridded maps of precipitation frequency for the NNSS and surrounding areas were then produced.

  5. Recognition memory for low- and high-frequency-filtered emotional faces: Low spatial frequencies drive emotional memory enhancement, whereas high spatial frequencies drive the emotion-induced recognition bias.

    Science.gov (United States)

    Rohr, Michaela; Tröger, Johannes; Michely, Nils; Uhde, Alarith; Wentura, Dirk

    2017-07-01

    This article deals with two well-documented phenomena regarding emotional stimuli: emotional memory enhancement-that is, better long-term memory for emotional than for neutral stimuli-and the emotion-induced recognition bias-that is, a more liberal response criterion for emotional than for neutral stimuli. Studies on visual emotion perception and attention suggest that emotion-related processes can be modulated by means of spatial-frequency filtering of the presented emotional stimuli. Specifically, low spatial frequencies are assumed to play a primary role for the influence of emotion on attention and judgment. Given this theoretical background, we investigated whether spatial-frequency filtering also impacts (1) the memory advantage for emotional faces and (2) the emotion-induced recognition bias, in a series of old/new recognition experiments. Participants completed incidental-learning tasks with high- (HSF) and low- (LSF) spatial-frequency-filtered emotional and neutral faces. The results of the surprise recognition tests showed a clear memory advantage for emotional stimuli. Most importantly, the emotional memory enhancement was significantly larger for face images containing only low-frequency information (LSF faces) than for HSF faces across all experiments, suggesting that LSF information plays a critical role in this effect, whereas the emotion-induced recognition bias was found only for HSF stimuli. We discuss our findings in terms of both the traditional account of different processing pathways for HSF and LSF information and a stimulus features account. The double dissociation in the results favors the latter account-that is, an explanation in terms of differences in the characteristics of HSF and LSF stimuli.

  6. Improvement of Frequency Locking Algorithm for Atomic Frequency Standards

    Science.gov (United States)

    Park, Young-Ho; Kang, Hoonsoo; Heyong Lee, Soo; Eon Park, Sang; Lee, Jong Koo; Lee, Ho Seong; Kwon, Taeg Yong

    2010-09-01

    The authors describe a novel method of frequency locking algorithm for atomic frequency standards. The new algorithm for locking the microwave frequency to the Ramsey resonance is compared with the old one that had been employed in the cesium atomic beam frequency standards such as NIST-7 and KRISS-1. Numerical simulations for testing the performance of the algorithm show that the new method has a noise filtering performance superior to the old one by a factor of 1.2 for the flicker signal noise and 1.4 for random-walk signal noise. The new algorithm can readily be used to enhance the frequency stability for a digital servo employing the slow square wave frequency modulation.

  7. 47 CFR 90.303 - Availability of frequencies.

    Science.gov (United States)

    2010-10-01

    ... table lists frequency bands that are available for assignment in specific urban areas. The available... available for use by eligibles in the Public Safety Radio Pool in the following areas: New York City; Nassau...)” curve in Figure B in 47 CFR 90.309(b). (ii) For base stations located west of the Hudson River, Kill Van...

  8. Frequency domain analysis of piping systems under short duration loading

    International Nuclear Information System (INIS)

    Sachs, K.; Sand, H.; Lockau, J.

    1981-01-01

    In piping analysis two procedures are used almost exclusively: the modal superposition method for relatively long input time histories (e.g., earthquake) and direct integration of the equations of motion for short input time histories. A third possibility, frequency domain analysis, has only rarely been applied to piping systems to date. This paper suggests the use of frequency domain analysis for specific piping problems for which only direct integration could be used in the past. Direct integration and frequency domain analysis are compared, and it is shown that the frequency domain method is less costly if more than four or five load cases are considered. In addition, this method offers technical advantages, such as more accurate representation of modal damping and greater insight into the structural behavior of the system. (orig.)

  9. Piezoelectric Actuator with Frequency Characteristics for a Middle-Ear Implant.

    Science.gov (United States)

    Shin, Dong Ho; Cho, Jin-Ho

    2018-05-24

    The design and implementation of a novel piezoelectric-based actuator for an implantable middle-ear hearing aid is described in this paper. The proposed actuator has excellent low-frequency output characteristics, and can generate high output in a specific frequency band by adjusting the mechanical resonance. The actuator consists of a piezoelectric element, a miniature bellows, a cantilever membrane, a metal ring support, a ceramic tip, and titanium housing. The optimal structure of the cantilever-membrane design, which determines the frequency characteristics of the piezoelectric actuator, was derived through finite element analysis. Based on the results, the piezoelectric actuator was implemented, and its performance was verified through a cadaveric experiment. It was confirmed that the proposed actuator provides better performance than currently used actuators, in terms of frequency characteristics.

  10. Ground Radar Polarimetric Observations of High-Frequency Earth-Space Communication Links

    Science.gov (United States)

    Bolen, Steve; Chandrasekar, V.; Benjamin, Andrew

    2002-01-01

    Strategic roadmaps for NASA's Human Exploration and Development of Space (REDS) enterprise support near-term high-frequency communication systems that provide moderate to high data rates with dependable service. Near-earth and human planetary exploration will baseline Ka-Band, but may ultimately require the use of even higher frequencies. Increased commercial demand on low-frequency earth-space bands has also led to increased interest in the use of higher frequencies in regions like K u - and K,- band. Data is taken from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), which operates at 13.8 GHz, and the true radar reflectivity profile is determined along the PR beam via low-frequency ground based polarimetric observations. The specific differential phase (Kdp) is measured along the beam and a theoretical model is used to determine the expected specific attenuation (k). This technique, called the k-Kdp method, uses a Fuzzy-Logic model to determine the hydrometeor type along the PR beam from which the appropriate k-Kdp relationship is used to determine k and, ultimately, the total path-integrated attenuation (PIA) on PR measurements. Measurements from PR and the NCAR S-POL radar were made during the TEFLUN-B experiment that took place near Melbourne, FL in 1998, and the TRMM-LBA campaign near Ji-Parana, Brazil in 1999.

  11. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  12. Theory of sum-frequency generation spectroscopy of adsorbed molecules using the density matrix method-broadband vibrational sum-frequency generation and applications

    International Nuclear Information System (INIS)

    Bonn, M; Ueba, H; Wolf, M

    2005-01-01

    A generalized theory of frequency- and time-resolved vibrational sum-frequency generation (SFG) spectroscopy of adsorbates at surfaces is presented using the density matrix formalism. Our theoretical treatment is specifically aimed at addressing issues that accompany the relatively novel SFG approach using broadband infrared pulses. The ultrashort duration of these pulses makes them ideally suited for time-resolved investigations, for which we present a complete theoretical treatment. A second key characteristic of these pulses is their large bandwidth and high intensity, which allow for highly non-linear effects, including vibrational ladder climbing of surface vibrations. We derive general expressions relating the density matrix to SFG spectra, and apply these expressions to specific experimental results by solving the coupled optical Bloch equations of the density matrix elements. Thus, we can theoretically reproduce recent experimentally demonstrated hot band SFG spectra using femtosecond broadband infrared excitation of carbon monoxide (CO) on a Ru(001) surface

  13. Resource partitioning of sonar frequency bands in rhinolophoid bats.

    Science.gov (United States)

    Heller, Klaus-Gerhard; Helversen, Otto V

    1989-08-01

    In the Constant Frequency portions of the orientation calls of various Rhinolophus and Hipposideros species, the frequency with the strongest amplitude was studied comparatively. (1) In the five European species of the genus Rhinolophus call frequencies are either species-specific (R. ferrumequinum, R. blasii and R. euryale) or they overlap (R. hipposideros and R. mehelyi). The call frequency distributions are approximately 5-9 kHz wide, thus their ranges spead less than ±5% from the mean (Fig. 1). Frequency distributions are considerably narrower within smaller geographic areas. (2) As in other bat groups, call frequencies of the Rhinolophoidea are negatively correlated with body size (Fig. 3). Regression lines for the genera Rhinolophus and Rhinolophus, species from dryer climates have on the average higher call frequencies than species from tropical rain forests. (4) The Krau Game Reserve, a still largely intact rain forest area in Malaysia, harbours at least 12 syntopic Rhinolophus and Hipposiderso species. Their call frequencies lie between 40 and 200 kHz (Fig. 2). Distribution over the available frequency range is significantly more even than could be expected from chance alone. Two different null hypotheses to test for random character distribution were derived from frequency-size-relations and by sampling species assemblages from a species pool (Monte Carlo method); both were rejected. In particular, call frequencies lying close together are avoided (Figs. 4, 5). Conversely, the distribution of size ratios complied with a corresponding null hypothesis. This even distribution may be a consequence of resource partitioning with respect to prey type. Alternatively, the importance of these calls as social signals (e.g. recognition of conspecifics) might have necessitated a communication channel partitioning.

  14. Numerical solution of optimal departure frequency of Taipei TMS

    Science.gov (United States)

    Young, Lih-jier; Chiu, Chin-Hsin

    2016-05-01

    Route Number 5 (Bannan Line) of Taipei Mass Rapid Transit (MRT) is the most popular line in the Taipei Metro System especially during rush hours periods. It has been estimated there are more than 8,000 passengers on the ticket platform during 18:00∼19:00 at Taipei main station. The purpose of this research is to predict a specific departure frequency of passengers per train. Monte Carlo Simulation will be used to optimize departure frequency according to the passenger information provided by 22 stations, i.e., 22 random variables of route number 5. It is worth mentioning that we used 30,000 iterations to get the different samples of the optimization departure frequency, i.e., 10 trains/hr which matches the practical situation.

  15. Trapped Ion Oscillation Frequencies as Sensors for Spectroscopy

    Directory of Open Access Journals (Sweden)

    Wilfried Nörtershäuser

    2010-03-01

    Full Text Available The oscillation frequencies of charged particles in a Penning trap can serve as sensors for spectroscopy when additional field components are introduced to the magnetic and electric fields used for confinement. The presence of so-called “magnetic bottles” and specific electric anharmonicities creates calculable energy-dependences of the oscillation frequencies in the radiofrequency domain which may be used to detect the absorption or emission of photons both in the microwave and optical frequency domains. The precise electronic measurement of these oscillation frequencies therefore represents an optical sensor for spectroscopy. We discuss possible applications for precision laser and microwave spectroscopy and their role in the determination of magnetic moments and excited state lifetimes. Also, the trap-assisted measurement of radiative nuclear de-excitations in the X-ray domain is discussed. This way, the different applications range over more than 12 orders of magnitude in the detectable photon energies, from below μeV in the microwave domain to beyond MeV in the X-ray domain.

  16. Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

    Directory of Open Access Journals (Sweden)

    Keisuke Fujisaki

    2013-11-01

    Full Text Available To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to introduce the equivalent material constants; water particles and aluminum particles are used as composite materials. Consumed electrical power is used for the evaluation. Water particles have the same equivalent material constants for both methods; the same electrical power is obtained for both the precise model (micro-model and the homogeneous model (macro-model. However, aluminum particles have dissimilar equivalent material constants for both methods; different electric power is obtained for both models. The varying electromagnetic phenomena are derived from the expression of eddy current. For small electrical conductivity such as water, the macro-current which flows in the macro-model and the micro-current which flows in the micro-model express the same electromagnetic phenomena. However, for large electrical conductivity such as aluminum, the macro-current and micro-current express different electromagnetic phenomena. The eddy current which is observed in the micro-model is not expressed by the macro-model. Therefore, the equivalent material constant derived from the volume averaged method and the standing wave method is applicable to water with a small electrical conductivity, although not applicable to aluminum with a large electrical conductivity.

  17. Meal frequency and childhood obesity.

    Science.gov (United States)

    Toschke, André M; Küchenhoff, Helmut; Koletzko, Berthold; von Kries, Rüdiger

    2005-11-01

    Previous studies have demonstrated an inverse association between meal frequency and the prevalence of obesity in adulthood. The aim of this study was to assess the relationship between meal frequency and childhood obesity. Stature and weight of 4,370 German children ages 5 to 6 years were determined in six Bavarian (Germany) public health offices during the obligatory school entry health examination in 2001/2002. An extensive questionnaire on risk factors for obesity was answered by their parents. Obesity was defined according to sex- and age-specific BMI cut-off points proposed by the International Obesity Task Force. The main exposure was daily meal frequency. The prevalence of obesity decreased by number of daily meals: three or fewer meals, 4.2% [95% confidence interval (CI), 2.8 to 6.1]; four meals, 2.8% (95% CI, 2.1 to 3.7); and 5 or more meals, 1.7% (95% CI, 1.2 to 2.4). These effects could not be explained by confounding due to a wide range of constitutional, sociodemographic, and lifestyle factors. The adjusted odds ratios for obesity were 0.73 (95% CI, 0.44 to 1.21) for four meals and 0.51 (95% CI, 0.29 to 0.89) for five or more meals. Additional analyses pointed to a higher energy intake in nibblers compared with gorgers. A protective effect of an increased daily meal frequency on obesity in children was observed and appeared to be independent of other risk factors for childhood obesity. A modulation of the response of hormones such as insulin might be instrumental.

  18. GHz band frequency hopping PLL-based frequency synthesizers

    Institute of Scientific and Technical Information of China (English)

    XU Yong; WANG Zhi-gong; GUAN Yu; XU Zhi-jun; QIAO Lu-feng

    2005-01-01

    In this paper we describe a full-integrated circuit containing all building blocks of a completed PLL-based synthesizer except for low pass filter(LPF).The frequency synthesizer is designed for a frequency hopping (FH) transceiver operating up to 1.5 GHz as a local oscillator. The architecture of Voltage Controlled Oscillator (VCO) is optimized to get better performance, and a phase noise of -111.85-dBc/Hz @ 1 MHz and a tuning range of 250 MHz are gained at a centre frequency of 1.35 GHz.A novel Dual-Modulus Prescaler(DMP) is designed to achieve a very low jitter and a lower power.The settling time of PLL is 80 μs while the reference frequency is 400 KHz.This monolithic frequency synthesizer is to integrate all main building blocks of PLL except for the low pass filter,with a maximum VCO output frequency of 1.5 GHz,and is fabricated with a 0.18 μm mixed signal CMOS process. Low power dissipation, low phase noise, large tuning range and fast settling time are gained in this design.

  19. Estimation of Internal Flooding Frequency for Screening Analysis of Flooding PSA

    International Nuclear Information System (INIS)

    Choi, Sun Yeong; Yang, Jun Eon

    2005-01-01

    The purpose of this paper is to estimate the internal frequency for the quantitative screening analysis of the flooding PSA (Probabilistic Safety Assessment) with the appropriate data and estimation method. In the case of the existing flood PSA for domestic NPPs (Nuclear Power Plant), the screening analysis was performed firstly and then detailed analysis was performed for the area not screened out. For the quantitative screening analysis, the plant area based flood frequency by MLE (Maximum Likelihood Estimation) method was used, while the component based flood frequency is used for the detailed analysis. The existing quantitative screening analysis for domestic NPPs have used data from all LWRs (Light Water Reactor), namely PWR (Pressurized Water Reactor) and BWR (Boiling Water Reactor) for the internal flood frequency of the auxiliary building and turbine building. However, in the case of the primary auxiliary building, the applicability of the data from all LWRs needs to be examined carefully because of the significant difference in equipments between the PWR and BWR structure. NUREG/CR-5750 suggested the Bayesian update method with Jeffrey's noninformative prior to estimate the initiating event frequency for the flood. It, however, did not describe any procedure of the flood PSA. Recently, Fleming and Lydell suggested the internal flooding frequency in the unit of the plant operation year-pipe length (in meter) by pipe size of each specific system which is susceptible to the flooding such as the service water system and the circulating water system. They used the failure rate, the rupture conditional probability given the failure to estimate the internal flooding frequency, and the Bayesian update to reduce uncertainties. To perform the quantitative screening analysis with the method, it requires pipe length by each pipe size of the specific system per each divided area to change the concept of the component based frequency to the concept of the plant area

  20. 47 CFR 25.202 - Frequencies, frequency tolerance and emission limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Frequencies, frequency tolerance and emission limitations. 25.202 Section 25.202 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical Standards § 25.202 Frequencies, frequency tolerance...

  1. Effect of feeding frequency and feeding rate on growth of ...

    African Journals Online (AJOL)

    Effect of feeding frequency and feeding rate on growth of Oreochromis mossambicus (Teleostei: Cichlidae) fry. ... Weight gain, specific growth rate and gross food conversion ratio were significantly affected by ... AJOL African Journals Online.

  2. Parametric effects of word frequency effect in memory for mixed frequency lists

    OpenAIRE

    Lohnas, Lynn J.; Kahana, Michael J.

    2013-01-01

    The word frequency paradox refers to the finding that low frequency words are better recognized than high frequency words yet high frequency words are better recalled than low frequency words. Rather than comparing separate groups of low and high frequency words, we sought to quantify the functional relation between word frequency and memory performance across the broad range of frequencies typically used in episodic memory experiments. Here we report that both low frequency and high frequenc...

  3. Herpes simplex virus specific T cell response in a cohort with primary genital infection correlates inversely with frequency of subsequent recurrences.

    Science.gov (United States)

    Franzen-Röhl, Elisabeth; Schepis, Danika; Atterfelt, Fredrik; Franck, Kristina; Wikström, Arne; Liljeqvist, Jan-Åke; Bergström, Tomas; Aurelius, Elisabeth; Kärre, Klas; Berg, Louise; Gaines, Hans

    2017-05-01

    During the last decades, a changing epidemiological pattern of genital herpes simplex virus (HSV) infection has emerged. Primary infection is now caused as often by HSV-1 as by HSV-2. Once established, HSV can be reactivated leading to recurrent mucocutaneous lesions as well as meningitis. Why some otherwise immune-competent individuals experience severe and frequent recurrences is not known, and the immunological mechanism underlying recurrent symptomatic HSV infection is not fully understood. In this study, we investigate and characterise the immune response of patients with first episode of HSV genital infection and its relation to the frequency of symptomatic recurrences. In this cohort study, clinical and immunological data were collected from 29 patients who were followed 1 year after presenting with a first episode of genital or meningeal HSV infection. They were classified by PCR and serology as those with primary HSV-1, primary HSV-2 and non-primary HSV-2 infection. HSV-specific interleukin(Il)-4 and Il-10 responses at first visit were higher in primary infected HSV-2 infected patients experiencing lower numbers of recurrences during subsequent year. The median number of recurrences following primary HSV-2 genital infection may partly be predicted by the strength of an early HSV-specific IL-4 and IL-10 response. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  4. Narrowband-to-Narrowband Frequency Reconfiguration with Harmonic Suppression Using Fractal Dipole Antenna

    Directory of Open Access Journals (Sweden)

    S. A. Hamzah

    2013-01-01

    Full Text Available Harmonic suppressed fractal antenna with switches named TMFDB25 is developed to select desired frequency band from 400 MHz to 3.5 GHz. The radiating element length is changed to tune the operating frequency while the stub is used to eliminate the undesired harmonic frequency. The balun circuit is reduced by 75% from the original size. The antenna is built on a low loss material. It has the ability to select a single frequency out of fifteen different bands and maintain the omnidirectional radiation pattern properties. Furthermore, the antenna is designed, built, and tested. Simulation and measurement results show that the antenna operates well at the specific frequency range. Therefore, the antenna is suitable to be used for switching frequencies in the band of TV, GSM900/1800, 3G, ISM 2.4 GHz, and above.

  5. The driving frequency effects on the atmospheric pressure corona jet plasmas from low frequency to radio frequency

    International Nuclear Information System (INIS)

    Kim, Dan Bee; Jung, H.; Gweon, B.; Rhee, J. K.; Choe, W.; Moon, S. Y.

    2011-01-01

    Lately, the atmospheric pressure jet type corona plasma, which has been typically driven by dc to low frequency (LF: several tens of kHz), is often generated by using radio frequency of 13.56 MHz. Yet, the relationship between the plasma and its driving frequency has seldom been investigated. Hence, in this study, dependence of the atmospheric pressure corona plasma characteristics on the driving frequency was explored experimentally from LF to rf (5 kHz-13.56 MHz). The plasmas generated by the driving frequency under 2 MHz were cylindrical shape of several tens of millimeters long while the 13.56 MHz plasma is spherical and a few millimeters long. As the driving frequency was increased, the plasma length became shortened. At the lower driving frequencies (below 2 MHz), the plasmas existed as positive streamer and negative glow for each half period of the applied voltage, but the discharge was more continuous in time for the 13.56 MHz plasma. It was inferred from the measured I-V curves that the higher driving frequency induced higher discharge currents, and the gas temperature was increased as the driving frequency was increased.

  6. Modal spectral analysis of piping: Determination of the significant frequency range

    International Nuclear Information System (INIS)

    Geraets, L.H.

    1981-01-01

    This paper investigates the influence of the number of modes on the response of a piping system in a dynamic modal spectral analysis. It shows how the analysis can be limited to a specific frequency range of the pipe (independent of the frequency range of the response spectrum), allowing cost reduction without loss in accuracy. The 'missing mass' is taken into account through an original technique. (orig./HP)

  7. Stimulus-dependent modulation of spontaneous low-frequency oscillations in the rat visual cortex.

    Science.gov (United States)

    Huang, Liangming; Liu, Yadong; Gui, Jianjun; Li, Ming; Hu, Dewen

    2014-08-06

    Research on spontaneous low-frequency oscillations is important to reveal underlying regulatory mechanisms in the brain. The mechanism for the stimulus modulation of low-frequency oscillations is not known. Here, we used the intrinsic optical imaging technique to examine stimulus-modulated low-frequency oscillation signals in the rat visual cortex. The stimulation was presented monocularly as a flashing light with different frequencies and intensities. The phases of low-frequency oscillations in different regions tended to be synchronized and the rhythms typically accelerated within a 30-s period after stimulation. These phenomena were confined to visual stimuli with specific flashing frequencies (12.5-17.5 Hz) and intensities (5-10 mA). The acceleration and synchronization induced by the flashing frequency were more marked than those induced by the intensity. These results show that spontaneous low-frequency oscillations can be modulated by parameter-dependent flashing lights and indicate the potential utility of the visual stimulus paradigm in exploring the origin and function of low-frequency oscillations.

  8. Skeletal site-specific effects of whole body vibration in mature rats: from deleterious to beneficial frequency-dependent effects.

    Science.gov (United States)

    Pasqualini, Marion; Lavet, Cédric; Elbadaoui, Mohamed; Vanden-Bossche, Arnaud; Laroche, Norbert; Gnyubkin, Vasily; Vico, Laurence

    2013-07-01

    Whole body vibration (WBV) is receiving increasing interest as an anti-osteoporotic prevention strategy. In this context, selective effects of different frequency and acceleration magnitude modalities on musculoskeletal responses need to be better defined. Our aim was to investigate the bone effects of different vibration frequencies at constant g level. Vertical WBV was delivered at 0.7 g (peak acceleration) and 8, 52 or 90 Hz sinusoidal vibration to mature male rats 10 min daily for 5 days/week for 4 weeks. Peak accelerations measured by skin or bone-mounted accelerometers at L2 vertebral and tibia crest levels revealed similar values between adjacent skin and bone sites. Local accelerations were greater at 8 Hz compared with 52 and 90 Hz and were greater in vertebra than tibia for all the frequencies tested. At 52 Hz, bone responses were mainly seen in L2 vertebral body and were characterized by trabecular reorganization and stimulated mineral apposition rate (MAR) without any bone volume alteration. At 90 Hz, axial and appendicular skeletons were affected as were the cortical and trabecular compartments. Cortical thickness increased in femur diaphysis (17%) along with decreased porosity; trabecular bone volume increased at distal femur metaphysis (23%) and even more at L2 vertebral body (32%), along with decreased SMI and increased trabecular connectivity. Trabecular thickness increased at the tibia proximal metaphysis. Bone cellular activities indicated a greater bone formation rate, which was more pronounced at vertebra (300%) than at long bone (33%). Active bone resorption surfaces were unaffected. At 8 Hz, however, hyperosteoidosis with reduced MAR along with increased resorption surfaces occurred in the tibia; hyperosteoidosis and trend towards decreased MAR was also seen in L2 vertebra. Trabecular bone mineral density was decreased at femur and tibia. Thus the most favorable regimen is 90 Hz, while deleterious effects were seen at 8 Hz. We concluded that

  9. Relaxation of inservice test frequency requirement for Kori 1 ASME code pumps

    International Nuclear Information System (INIS)

    Sohn, Gap Heon; Choi, Hae Yoon; Min, Kyung Sung; Rim, Nam Jin

    1994-08-01

    The objective of this investigation is to evaluate the technical and regulational requirements to justify the relaxation of the test frequency of Kori 1 pumps through reviewing the related rules and codes and standards, technical specifications of Kori 1 and other similar plants, standard technical specifications, research results for tech. spec. improvements and site test records. It is concluded that the relaxation of test frequency to quarterly be justified based on the conformance with rules and codes and standard, quarterly test cases in similar plants and standard tech. spec., recommendations of research result and stable site test records. (Author) 16 refs., 26 figs., 13 tabs

  10. Chemical and radiochemical specifications - PWR power plants

    International Nuclear Information System (INIS)

    Stutzmann, A.

    1997-01-01

    Published by EDF this document gives the chemical specifications of the PWR (Pressurized Water Reactor) nuclear power plants. Among the chemical parameters, some have to be respected for the safety. These parameters are listed in the STE (Technical Specifications of Exploitation). The values to respect, the analysis frequencies and the time states of possible drops are noticed in this document with the motion STE under the concerned parameter. (A.L.B.)

  11. Effect of high-frequency excitation on natural frequencies of spinning discs

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2000-01-01

    The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc......The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural...

  12. Design and Industrial Production of Frequency Standards in the USSR

    Science.gov (United States)

    1990-12-01

    VNIIFTRI ), the measurement data, taken in January-May interval of 1990, the frequency drift of four CHI-80 instruments was less than 1 x 10-l6 per day13...hydrogen keeper specifications received by VNIIFTRI . The frequency reproducibility is 5 x 10-l4 for the measurement interval up to 16 hours[16]. At...in hydrogen maser in new materials Proc. VNIIFTRI Issledovarliya v oblasty izmereny vremeny i chastoty. Moscow, 1978, v.37(67), P.81-85 2. S.B

  13. Analysis of East Tank Farms Contamination Survey Frequency

    International Nuclear Information System (INIS)

    ELDER, R.E.

    2000-01-01

    This document provides the justification for the change in survey frequency in East Tank Farms occupied contamination areas from weekly to monthly. The Tank Farms Radiological Control Organization has performed radiological surveys of its Contamination Area (CA) Double Shell Tank (DST) farms in 200 East Area on a weekly basis for several years. The task package (DST-W012) controlling these routines designates specific components, at a minimum, that must be surveyed whenever the task is performed. This document documents the evaluation of these survey requirements and provides the recommendation and basis for moving DST tank farms in the 200 East Area from a weekly to monthly contamination survey. The contamination surveys for occupied contamination areas in West Tank Farms (WTF) were changed from a weekly frequency to a monthly frequency in 1997. Review of contamination survey data in WTF indicates a monthly interval remains satisfactory

  14. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  15. Task and spatial frequency modulations of object processing: an EEG study.

    Science.gov (United States)

    Craddock, Matt; Martinovic, Jasna; Müller, Matthias M

    2013-01-01

    Visual object processing may follow a coarse-to-fine sequence imposed by fast processing of low spatial frequencies (LSF) and slow processing of high spatial frequencies (HSF). Objects can be categorized at varying levels of specificity: the superordinate (e.g. animal), the basic (e.g. dog), or the subordinate (e.g. Border Collie). We tested whether superordinate and more specific categorization depend on different spatial frequency ranges, and whether any such dependencies might be revealed by or influence signals recorded using EEG. We used event-related potentials (ERPs) and time-frequency (TF) analysis to examine the time course of object processing while participants performed either a grammatical gender-classification task (which generally forces basic-level categorization) or a living/non-living judgement (superordinate categorization) on everyday, real-life objects. Objects were filtered to contain only HSF or LSF. We found a greater positivity and greater negativity for HSF than for LSF pictures in the P1 and N1 respectively, but no effects of task on either component. A later, fronto-central negativity (N350) was more negative in the gender-classification task than the superordinate categorization task, which may indicate that this component relates to semantic or syntactic processing. We found no significant effects of task or spatial frequency on evoked or total gamma band responses. Our results demonstrate early differences in processing of HSF and LSF content that were not modulated by categorization task, with later responses reflecting such higher-level cognitive factors.

  16. Combining agreement and frequency rating scales to optimize psychometrics in measuring behavioral health functioning.

    Science.gov (United States)

    Marfeo, Elizabeth E; Ni, Pengsheng; Chan, Leighton; Rasch, Elizabeth K; Jette, Alan M

    2014-07-01

    The goal of this article was to investigate optimal functioning of using frequency vs. agreement rating scales in two subdomains of the newly developed Work Disability Functional Assessment Battery: the Mood & Emotions and Behavioral Control scales. A psychometric study comparing rating scale performance embedded in a cross-sectional survey used for developing a new instrument to measure behavioral health functioning among adults applying for disability benefits in the United States was performed. Within the sample of 1,017 respondents, the range of response category endorsement was similar for both frequency and agreement item types for both scales. There were fewer missing values in the frequency items than the agreement items. Both frequency and agreement items showed acceptable reliability. The frequency items demonstrated optimal effectiveness around the mean ± 1-2 standard deviation score range; the agreement items performed better at the extreme score ranges. Findings suggest an optimal response format requires a mix of both agreement-based and frequency-based items. Frequency items perform better in the normal range of responses, capturing specific behaviors, reactions, or situations that may elicit a specific response. Agreement items do better for those whose scores are more extreme and capture subjective content related to general attitudes, behaviors, or feelings of work-related behavioral health functioning. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Climatic variations, trends and drought frequency in Dejen District ...

    African Journals Online (AJOL)

    ... and expected to increase in the future. This implies that the country specifically the study area whose mainstay depends on agriculture must cope with further warming, low, and erratic rainfall, and frequent climatic extremes. Keywords: Climate change, drought frequency, standardized precipitation index, rainfall variations ...

  18. A Frequency Domain Design Method For Sampled-Data Compensators

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Jannerup, Ole Erik

    1990-01-01

    A new approach to the design of a sampled-data compensator in the frequency domain is investigated. The starting point is a continuous-time compensator for the continuous-time system which satisfy specific design criteria. The new design method will graphically show how the discrete...

  19. Frequency, probability, and prediction: easy solutions to cognitive illusions?

    Science.gov (United States)

    Griffin, D; Buehler, R

    1999-02-01

    Many errors in probabilistic judgment have been attributed to people's inability to think in statistical terms when faced with information about a single case. Prior theoretical analyses and empirical results imply that the errors associated with case-specific reasoning may be reduced when people make frequentistic predictions about a set of cases. In studies of three previously identified cognitive biases, we find that frequency-based predictions are different from-but no better than-case-specific judgments of probability. First, in studies of the "planning fallacy, " we compare the accuracy of aggregate frequency and case-specific probability judgments in predictions of students' real-life projects. When aggregate and single-case predictions are collected from different respondents, there is little difference between the two: Both are overly optimistic and show little predictive validity. However, in within-subject comparisons, the aggregate judgments are significantly more conservative than the single-case predictions, though still optimistically biased. Results from studies of overconfidence in general knowledge and base rate neglect in categorical prediction underline a general conclusion. Frequentistic predictions made for sets of events are no more statistically sophisticated, nor more accurate, than predictions made for individual events using subjective probability. Copyright 1999 Academic Press.

  20. Stable radio frequency dissemination by simple hybrid frequency modulation scheme.

    Science.gov (United States)

    Yu, Longqiang; Wang, Rong; Lu, Lin; Zhu, Yong; Wu, Chuanxin; Zhang, Baofu; Wang, Peizhang

    2014-09-15

    In this Letter, we propose a fiber-based stable radio frequency transfer system by a hybrid frequency modulation scheme. Creatively, two radio frequency signals are combined and simultaneously transferred by only one laser diode. One frequency component is used to detect the phase fluctuation, and the other one is the derivative compensated signal providing a stable frequency for the remote end. A proper ratio of the frequencies of the components is well maintained by parameter m to avoid interference between them. Experimentally, a stable 200 MHz signal is transferred over 100 km optical fiber with the help of a 1 GHz detecting signal, and fractional instability of 2×10(-17) at 10(5) s is achieved.

  1. Resonator as high frequency electromagnetic field oscillation generator

    International Nuclear Information System (INIS)

    Svoroba, O.V.; Scherbina, V.O.

    2007-01-01

    The problem of finding the u(x-vector) field potential in a specific waveguide with generalized corrugated core geometry is considered. The perturbation is brought to the system by high energy electron beam, injected in a waveguide. It is shown that the Neumann spectral problem can be reduced to finding Green approximation solution, and how it can be solved by the discretization technique. Considered parameterization allow to optimize the u(x-vector) field for specific frequency tuning. This method can be used as plasma heating method for thermonuclear temperature control

  2. Validation of a Semi-Quantitative Food Frequency Questionnaire for Argentinean Adults

    OpenAIRE

    Dehghan, Mahshid; del Cerro, Silvia; Zhang, Xiaohe; Cuneo, Jose Maini; Linetzky, Bruno; Diaz, Rafael; Merchant, Anwar T.

    2012-01-01

    BACKGROUND: The Food Frequency Questionnaire (FFQ) is the most commonly used method for ranking individuals based on long term food intake in large epidemiological studies. The validation of an FFQ for specific populations is essential as food consumption is culture dependent. The aim of this study was to develop a Semi-quantitative Food Frequency Questionnaire (SFFQ) and evaluate its validity and reproducibility in estimating nutrient intake in urban and rural areas of Argentina. METHODS/PRI...

  3. Passive ultra high frequency radio frequency identification systems for single-item identification in food supply chains

    Directory of Open Access Journals (Sweden)

    Paolo Barge

    2017-02-01

    Full Text Available In the food industry, composition, size, and shape of items are much less regular than in other commodities sectors. In addition, a wide variety of packaging, composed by different materials, is employed. As material, size and shape of items to which the tag should be attached strongly influence the minimum power requested for tag functioning, performance improvements can be achieved only selecting suitable radio frequency (RF identifiers for the specific combination of food product and packaging. When dealing with logistics units, the dynamic reading of a vast number of tags could originate simultaneous broadcasting of signals (tag-to-tag collisions that could affect reading rates and the overall reliability of the identification procedure. This paper reports the results of an analysis of the reading performance of ultra high frequency radio frequency identification systems for multiple static and dynamic electronic identification of food packed products in controlled conditions. Products were considered when arranged on a logistics pallet. The effects on reading rate of different factors, among which the product type, the gate configuration, the field polarisation, the power output of the RF reader, the interrogation protocol configuration as well as the transit speed, the number of tags and their interactions were statistically analysed and compared.

  4. Analysis of Various Frequency Selective Shielding Glass by FDTD method

    OpenAIRE

    笠嶋, 善憲; Kasashima, Yoshinori

    2012-01-01

    A frequency Selective shielding (FSS) glass is a print of many same size antennas on a sheet of glass, and it has high shielding properties for one specific frequency. This time, the author analyzed characteristics of various FSSs whose antenna types are different by FDTD method. The antenna types are cross dipole, circular loop, square loop, circular patch, and square patch. As the result, the FSSs can be composed of the various types of the antennas, and the FSSs have broad-band shielding c...

  5. Frequency effects and structural change – the Afrikaans preterite

    African Journals Online (AJOL)

    According to emergent grammar and exemplar theory in cognitive linguistics, the frequency of an item affects its ... cognitive representation of language and language processing, and illustrates how the use of language .... large clouds of recalled tokens of specific categories, which is organised in a cognitive map where.

  6. Frequency of bedwetting among primary school children in Benha ...

    African Journals Online (AJOL)

    Objectives: The overall objective was health promotion of school children, and the specific objectives were: to determine the frequency and risk factors of nocturnal enuresis (NE) among school children in Qaluobia governorate Egypt, and to examine its associations with behavioral and emotional problems. Subjects and ...

  7. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences...

  8. On the specific heat in a limited medium

    International Nuclear Information System (INIS)

    Suzuki, A.T.

    1980-03-01

    The specific heat of solids is studied, following the usual approach in which the solid is considered as an elastic, isotropic and continuum system which bears normal modes of characteristic frequency. (L.C.) [pt

  9. REMODELING SENSORY CORTICAL MAPS IMPLANTS SPECIFIC BEHAVIORAL MEMORY

    Science.gov (United States)

    Bieszczad, Kasia M.; Miasnikov, Alexandre A.; Weinberger, Norman M.

    2013-01-01

    Neural mechanisms underlying the capacity of memory to be rich with sensory detail are largely unknown. A candidate mechanism is learning-induced plasticity that remodels adult sensory cortex. Here, expansion in the primary auditory cortical (A1) tonotopic map of rats was induced by pairing a 3.66 kHz tone with activation of the nucleus basalis, mimicking the effects of natural associative learning. Remodeling of A1 produced de novo specific behavioral memory, but neither memory nor plasticity were consistently at the frequency of the paired tone, which typically decreased in A1 representation. Rather, there was a specific match between individual subjects’ area of expansion and the tone that was strongest in each animal’s memory, as determined by post-training frequency generalization gradients. These findings provide the first demonstration of a match between the artificial induction of specific neural representational plasticity and artificial induction of behavioral memory. As such, together with prior and present findings for detection, correlation and mimicry of plasticity with the acquisition of memory, they satisfy a key criterion for neural substrates of memory. This demonstrates that directly remodeling sensory cortical maps is sufficient for the specificity of memory formation. PMID:23639876

  10. Individual Alpha Peak Frequency Predicts 10 Hz Flicker Effects on Selective Attention.

    Science.gov (United States)

    Gulbinaite, Rasa; van Viegen, Tara; Wieling, Martijn; Cohen, Michael X; VanRullen, Rufin

    2017-10-18

    Rhythmic visual stimulation ("flicker") is primarily used to "tag" processing of low-level visual and high-level cognitive phenomena. However, preliminary evidence suggests that flicker may also entrain endogenous brain oscillations, thereby modulating cognitive processes supported by those brain rhythms. Here we tested the interaction between 10 Hz flicker and endogenous alpha-band (∼10 Hz) oscillations during a selective visuospatial attention task. We recorded EEG from human participants (both genders) while they performed a modified Eriksen flanker task in which distractors and targets flickered within (10 Hz) or outside (7.5 or 15 Hz) the alpha band. By using a combination of EEG source separation, time-frequency, and single-trial linear mixed-effects modeling, we demonstrate that 10 Hz flicker interfered with stimulus processing more on incongruent than congruent trials (high vs low selective attention demands). Crucially, the effect of 10 Hz flicker on task performance was predicted by the distance between 10 Hz and individual alpha peak frequency (estimated during the task). Finally, the flicker effect on task performance was more strongly predicted by EEG flicker responses during stimulus processing than during preparation for the upcoming stimulus, suggesting that 10 Hz flicker interfered more with reactive than proactive selective attention. These findings are consistent with our hypothesis that visual flicker entrained endogenous alpha-band networks, which in turn impaired task performance. Our findings also provide novel evidence for frequency-dependent exogenous modulation of cognition that is determined by the correspondence between the exogenous flicker frequency and the endogenous brain rhythms. SIGNIFICANCE STATEMENT Here we provide novel evidence that the interaction between exogenous rhythmic visual stimulation and endogenous brain rhythms can have frequency-specific behavioral effects. We show that alpha-band (10 Hz) flicker impairs stimulus

  11. RareVar: A Framework for Detecting Low-Frequency Single-Nucleotide Variants.

    Science.gov (United States)

    Hao, Yangyang; Xuei, Xiaoling; Li, Lang; Nakshatri, Harikrishna; Edenberg, Howard J; Liu, Yunlong

    2017-07-01

    Accurate identification of low-frequency somatic point mutations in tumor samples has important clinical utilities. Although high-throughput sequencing technology enables capturing such variants while sequencing primary tumor samples, our ability for accurate detection is compromised when the variant frequency is close to the sequencer error rate. Most current experimental and bioinformatic strategies target mutations with ≥5% allele frequency, which limits our ability to understand the cancer etiology and tumor evolution. We present an experimental and computational modeling framework, RareVar, to reliably identify low-frequency single-nucleotide variants from high-throughput sequencing data under standard experimental protocols. RareVar protocol includes a benchmark design by pooling DNAs from already sequenced individuals at various concentrations to target variants at desired frequencies, 0.5%-3% in our case. By applying a generalized, linear model-based, position-specific error model, followed by machine-learning-based variant calibration, our approach outperforms existing methods. Our method can be applied on most capture and sequencing platforms without modifying the experimental protocol.

  12. Human haemodynamic frequency harmonics regulate the inflammatory phenotype of vascular endothelial cells.

    Science.gov (United States)

    Feaver, Ryan E; Gelfand, Bradley D; Blackman, Brett R

    2013-01-01

    Haemodynamic variations are inherent to blood vessel geometries (such as bifurcations) and correlate with regional development of inflammation and atherosclerosis. However, the complex frequency spectrum characteristics from these haemodynamics have never been exploited to test whether frequency variations are critical determinants of endothelial inflammatory phenotype. Here we utilize an experimental Fourier transform analysis to systematically manipulate individual frequency harmonics from human carotid shear stress waveforms applied in vitro to human endothelial cells. The frequency spectrum, specifically the 0 th and 1st harmonics, is a significant regulator of inflammation, including NF-κB activity and downstream inflammatory phenotype. Further, a harmonic-based regression-model predicts eccentric NF-κB activity observed in the human internal carotid artery. Finally, short interfering RNA-knockdown of the mechanosensor PECAM-1 reverses frequency-dependent regulation of NF-κB activity. Thus, PECAM-1 may have a critical role in the endothelium's exquisite sensitivity to complex shear stress frequency harmonics and provide a mechanism for the focal development of vascular inflammation.

  13. Closed-Cycle, Frequency-Stable CO2 Laser Technology

    Science.gov (United States)

    Batten, Carmen E. (Editor); Miller, Irvin M. (Editor); Wood, George M., Jr. (Editor); Willetts, David V. (Editor)

    1987-01-01

    These proceedings contain a collection of papers and comments presented at a workshop on technology associated with long-duration closed-cycle operation of frequency-stable, pulsed carbon dioxide lasers. This workshop was held at the NASA Langley Research Center June 10 to 12, 1986. The workshop, jointly sponsored by the National Aeronautics and Space Administration (NASA) and the Royal Signals and Radar Establishment (RSRE), was attended by 63 engineers and scientists from the United States and the United Kingdom. During the 2 1/2 days of the workshop, a number of issues relating to obtaining frequency-stable operation and to the catalytic control of laser gas chemistry were discussed, and specific recommendations concerning future activities were drafted.

  14. Frequencies in the Vibration Induced by the Rotor Stator Interaction in a Centrifugal Pump Turbine

    DEFF Research Database (Denmark)

    Rodriguez, Cristian; Egusquiza, Eduard; Santos, Ilmar

    2007-01-01

    The highest vibration levels in large pump turbines are, in general, originated in the rotor stator interaction (RSI). This vibration has specific characteristics that can be clearly observed in the frequency domain: harmonics of the moving blade passing frequency and a particular relationship am...

  15. Numerical investigations of single bubble oscillations generated by a dual frequency excitation

    International Nuclear Information System (INIS)

    Guédra, Matthieu; Inserra, Claude; Gilles, Bruno; Béra, Jean-Christophe

    2015-01-01

    The oscillations of a single bubble excited with a dual frequency acoustic field are numerically investigated. Computations are made for an air bubble in water exposed to an acoustic field with a linearly varying amplitude. The bubble response to an excitation containing two frequencies f 1 = 500 kHz and f 2 = 400 kHz at the same amplitude is compared to the monofrequency case where only f 1 is present. Time-frequency representations show a sharp transition in the bifrequency case, for which the low frequency component f 2 becomes resonant while the high frequency component f 1 is strongly attenuated. The temporal evolution of the power spectra reveals that the resonance of the low frequency component is correlated with the time varying mean radius of the bubble. It is also observed that the total power of the bubble response in the bifrequency case can reach almost twice the power obtained in the monofrequency case, which indicates a strong enhancement of the cavitating behavior of the bubble for this specific frequency combination. (paper)

  16. Frequencies of X-ray and fast neutron induced chromosome translocations in human peripheral blood lymphocytes as detected by in situ hybridization using chromosome specific DNA libraries

    International Nuclear Information System (INIS)

    Natarajan, A.T.; Darroudi, F.; Vermeulen, S.; Wiegant, J.

    1992-01-01

    DNA libraries of six human chromosomes were used to detect translocations in human lymphocytes induced by different doses of X-rays and fast neutrons. Results show that with X-rays, one can detect about 1.5 to 2.0 fold more translocations in comparison to dicentrics, whereas following fast neutron irradiation, the difference between these two classes of aberrations are significantly different at high doses. In addition, triple fluorescent in situ hybridization technique was used to study the frequencies of radiation-induced translocations involving a specific chromosome. Chromosome number 1 was found to be involved in translocations more frequently than chromosomes number 2, 3, 4, 8 and X. (author). 10 refs., 1 fig., 2 tabs

  17. Relationship between wingbeat frequency and resonant frequency of the wing in insects

    International Nuclear Information System (INIS)

    Ha, Ngoc San; Truong, Quang Tri; Goo, Nam Seo; Park, Hoon Cheol

    2013-01-01

    In this study, we experimentally studied the relationship between wingbeat frequency and resonant frequency of 30 individuals of eight insect species from five orders: Odonata (Sympetrum flaveolum), Lepidoptera (Pieris rapae, Plusia gamma and Ochlodes), Hymenoptera (Xylocopa pubescens and Bombus rupestric), Hemiptera (Tibicen linnei) and Coleoptera (Allomyrina dichotoma). The wingbeat frequency of free-flying insects was measured using a high-speed camera while the natural frequency was determined using a laser displacement sensor along with a Bruel and Kjaer fast Fourier transform analyzer based on the base excitation method. The results showed that the wingbeat frequency was related to body mass (m) and forewing area (A f ), following the proportionality f ∼ m 1/2 /A f , while the natural frequency was significantly correlated with area density (f 0  ∼ m w /A f , m w is the wing mass). In addition, from the comparison of wingbeat frequency to natural frequency, the ratio between wingbeat frequency and natural frequency was found to be, in general, between 0.13 and 0.67 for the insects flapping at a lower wingbeat frequency (less than 100 Hz) and higher than 1.22 for the insects flapping at a higher wingbeat frequency (higher than 100 Hz). These results suggest that wingbeat frequency does not have a strong relation with resonance frequency: in other words, insects have not been evolved sufficiently to flap at their wings' structural resonant frequency. This contradicts the general conclusion of other reports-–that insects flap at their wings' resonant frequency to take advantage of passive deformation to save energy. (paper)

  18. Energy harvesting from low frequency applications using piezoelectric materials

    International Nuclear Information System (INIS)

    Li, Huidong; Tian, Chuan; Deng, Z. Daniel

    2014-01-01

    In an effort to eliminate the replacement of the batteries of electronic devices that are difficult or impractical to service once deployed, harvesting energy from mechanical vibrations or impacts using piezoelectric materials has been researched over the last several decades. However, a majority of these applications have very low input frequencies. This presents a challenge for the researchers to optimize the energy output of piezoelectric energy harvesters, due to the relatively high elastic moduli of piezoelectric materials used to date. This paper reviews the current state of research on piezoelectric energy harvesting devices for low frequency (0–100 Hz) applications and the methods that have been developed to improve the power outputs of the piezoelectric energy harvesters. Various key aspects that contribute to the overall performance of a piezoelectric energy harvester are discussed, including geometries of the piezoelectric element, types of piezoelectric material used, techniques employed to match the resonance frequency of the piezoelectric element to input frequency of the host structure, and electronic circuits specifically designed for energy harvesters

  19. Task and spatial frequency modulations of object processing: an EEG study.

    Directory of Open Access Journals (Sweden)

    Matt Craddock

    Full Text Available Visual object processing may follow a coarse-to-fine sequence imposed by fast processing of low spatial frequencies (LSF and slow processing of high spatial frequencies (HSF. Objects can be categorized at varying levels of specificity: the superordinate (e.g. animal, the basic (e.g. dog, or the subordinate (e.g. Border Collie. We tested whether superordinate and more specific categorization depend on different spatial frequency ranges, and whether any such dependencies might be revealed by or influence signals recorded using EEG. We used event-related potentials (ERPs and time-frequency (TF analysis to examine the time course of object processing while participants performed either a grammatical gender-classification task (which generally forces basic-level categorization or a living/non-living judgement (superordinate categorization on everyday, real-life objects. Objects were filtered to contain only HSF or LSF. We found a greater positivity and greater negativity for HSF than for LSF pictures in the P1 and N1 respectively, but no effects of task on either component. A later, fronto-central negativity (N350 was more negative in the gender-classification task than the superordinate categorization task, which may indicate that this component relates to semantic or syntactic processing. We found no significant effects of task or spatial frequency on evoked or total gamma band responses. Our results demonstrate early differences in processing of HSF and LSF content that were not modulated by categorization task, with later responses reflecting such higher-level cognitive factors.

  20. The effect of high-frequency ground motion on the MAPLE-X10 reactor

    International Nuclear Information System (INIS)

    Bhan, S.; Dunbar, S.

    1989-06-01

    The effect of high-frequency ground motion on structures and equipment in nuclear reactors is examined by subjecting simple linear models to selected recorded ground motions which exhibit low and high frequencies. Computed damage measures indicate that high-frequency short-duration ground motion, such as that observed in eastern North America, have a minimal effect on structures with low natural frequencies. Response spectra of high-frequency ground motion indicate that higher forces are induced in structures with high natural frequencies as compared to those induced by low-frequency ground motion. However, reported observations of earthquake damage in eastern North America suggest that high-frequency ground motion causes little of no damage to structures. This may be due to the energy absorption capability of structures. It is concluded that the response spectrum representative of ground motion observed in eastern North America may give an over-conservative measure of the response of structures with high natural frequencies, since it does not account for the typically observed short duration of high-frequency ground motion and for the energy absorption capability of structures. Detailed nonlinear analysis of specific structures with high natural frequencies should be performed to better predict the actual response. Recommendations for a nonlinear analysis of typical structures with high natural frequencies are made

  1. Frequency spirals

    International Nuclear Information System (INIS)

    Ottino-Löffler, Bertrand; Strogatz, Steven H.

    2016-01-01

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  2. Frequency spirals

    Energy Technology Data Exchange (ETDEWEB)

    Ottino-Löffler, Bertrand; Strogatz, Steven H., E-mail: strogatz@cornell.edu [Center for Applied Mathematics, Cornell University, Ithaca, New York 14853 (United States)

    2016-09-15

    We study the dynamics of coupled phase oscillators on a two-dimensional Kuramoto lattice with periodic boundary conditions. For coupling strengths just below the transition to global phase-locking, we find localized spatiotemporal patterns that we call “frequency spirals.” These patterns cannot be seen under time averaging; they become visible only when we examine the spatial variation of the oscillators' instantaneous frequencies, where they manifest themselves as two-armed rotating spirals. In the more familiar phase representation, they appear as wobbly periodic patterns surrounding a phase vortex. Unlike the stationary phase vortices seen in magnetic spin systems, or the rotating spiral waves seen in reaction-diffusion systems, frequency spirals librate: the phases of the oscillators surrounding the central vortex move forward and then backward, executing a periodic motion with zero winding number. We construct the simplest frequency spiral and characterize its properties using analytical and numerical methods. Simulations show that frequency spirals in large lattices behave much like this simple prototype.

  3. Frequency modulation of neural oscillations according to visual task demands.

    Science.gov (United States)

    Wutz, Andreas; Melcher, David; Samaha, Jason

    2018-02-06

    Temporal integration in visual perception is thought to occur within cycles of occipital alpha-band (8-12 Hz) oscillations. Successive stimuli may be integrated when they fall within the same alpha cycle and segregated for different alpha cycles. Consequently, the speed of alpha oscillations correlates with the temporal resolution of perception, such that lower alpha frequencies provide longer time windows for perceptual integration and higher alpha frequencies correspond to faster sampling and segregation. Can the brain's rhythmic activity be dynamically controlled to adjust its processing speed according to different visual task demands? We recorded magnetoencephalography (MEG) while participants switched between task instructions for temporal integration and segregation, holding stimuli and task difficulty constant. We found that the peak frequency of alpha oscillations decreased when visual task demands required temporal integration compared with segregation. Alpha frequency was strategically modulated immediately before and during stimulus processing, suggesting a preparatory top-down source of modulation. Its neural generators were located in occipital and inferotemporal cortex. The frequency modulation was specific to alpha oscillations and did not occur in the delta (1-3 Hz), theta (3-7 Hz), beta (15-30 Hz), or gamma (30-50 Hz) frequency range. These results show that alpha frequency is under top-down control to increase or decrease the temporal resolution of visual perception.

  4. A mechanism for frequency modulation in songbirds shared with humans.

    Science.gov (United States)

    Amador, Ana; Margoliash, Daniel

    2013-07-03

    In most animals that vocalize, control of fundamental frequency is a key element for effective communication. In humans, subglottal pressure controls vocal intensity but also influences fundamental frequency during phonation. Given the underlying similarities in the biomechanical mechanisms of vocalization in humans and songbirds, songbirds offer an attractive opportunity to study frequency modulation by pressure. Here, we present a novel technique for dynamic control of subsyringeal pressure in zebra finches. By regulating the opening of a custom-built fast valve connected to the air sac system, we achieved partial or total silencing of specific syllables, and could modify syllabic acoustics through more complex manipulations of air sac pressure. We also observed that more nuanced pressure variations over a limited interval during production of a syllable concomitantly affected the frequency of that syllable segment. These results can be explained in terms of a mathematical model for phonation that incorporates a nonlinear description for the vocal source capable of generating the observed frequency modulations induced by pressure variations. We conclude that the observed interaction between pressure and frequency was a feature of the source, not a result of feedback control. Our results indicate that, beyond regulating phonation or its absence, regulation of pressure is important for control of fundamental frequencies of vocalizations. Thus, although there are separate brainstem pathways for syringeal and respiratory control of song production, both can affect airflow and frequency. We hypothesize that the control of pressure and frequency is combined holistically at higher levels of the vocalization pathways.

  5. Is Reaction Time Variability in ADHD Mainly at Low Frequencies?

    Science.gov (United States)

    Karalunas, Sarah L.; Huang-Pollock, Cynthia L.; Nigg, Joel T.

    2013-01-01

    Background: Intraindividual variability in reaction times (RT variability) has garnered increasing interest as an indicator of cognitive and neurobiological dysfunction in children with attention deficit hyperactivity disorder (ADHD). Recent theory and research has emphasized specific low-frequency patterns of RT variability. However, whether…

  6. Core damage frequency perspectives based on IPE results

    International Nuclear Information System (INIS)

    Dingman, S.E.; Camp, A.L.; LaChance, J.L.; Drouin, M.T.

    1996-01-01

    In November 1988, the US Nuclear Regulatory Commission (NRC) issued Generic Letter 88-20 requesting that all licensees perform an individual Plant Examination (IPE) to identify any plant-specific vulnerability to severe accidents and report the results to the Commission. This paper provides perspectives gained from reviewing 75 Individual Plant Examination (IPE) submittals covering 108 nuclear power plant units. Variability both within and among reactor types is examined to provide perspectives regarding plant-specific design and operational features, and modeling assumptions that play a significant role in the estimates of core damage frequencies in the IPEs

  7. An estimator for the standard deviation of a natural frequency. II.

    Science.gov (United States)

    Schiff, A. J.; Bogdanoff, J. L.

    1971-01-01

    A method has been presented for estimating the variability of a system's natural frequencies arising from the variability of the system's parameters. The only information required to obtain the estimates is the member variability, in the form of second-order properties, and the natural frequencies and mode shapes of the mean system. It has also been established for the systems studied by means of Monte Carlo estimates that the specification of second-order properties is an adequate description of member variability.

  8. Visual feedback of own tics increases tic frequency in patients with Tourette's syndrome.

    Science.gov (United States)

    Brandt, V C; Lynn, M T; Obst, M; Brass, M; Münchau, A

    2015-01-01

    Gilles de la Tourette syndrome (GTS) is characterized by motor and phonic tics. It is unknown how paying attention to one's own tics might modulate tic frequency. We determined tic frequency in freely ticcing GTS patients while they were being filmed. In Study 1, we investigated 12 patients (1) alone in a room (baseline); (2) alone in front of a mirror. In Study 2, we replicated these conditions in 16 patients and additionally examined how watching a video, in which the individual was shown not ticcing, affected their tic frequency. In both studies, tic frequency was significantly higher when patients watched themselves in a mirror compared to baseline. In contrast, tic frequency was significantly reduced in the video condition. Paying attention to one's own tics increases tic frequency when tics are not suppressed and appears to be specific for attention to tics, rather than attention to the self.

  9. The Low-Frequency Encoding Disadvantage: Word Frequency Affects Processing Demands

    OpenAIRE

    Diana, Rachel A.; Reder, Lynne M.

    2006-01-01

    Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g., L. M. Reder et al., 2000). When tasks other than recognition, such as recall, cued recall, or associative recognition, are used, the effects seem to contradict a low-frequency advantage in memory. Four experiments are presented to support the claim that in ad...

  10. Observations on the Reliability of Rubidium Frequency Standards on Block 2/2A GPS Satellites

    Science.gov (United States)

    Dieter, Gary L.

    1996-01-01

    Currently, the block 2/2A Global Positioning System (GPS) satellites are equipped with two rubidium frequency standards. These frequency standards were originally intended to serve as the back-ups to two cesium frequency standards. As the constellation ages, the master Control Station is forced to initialize and increasing number or rubidium frequency standards. Unfortunately the operational use of these frequency standards has not lived up to initial expectations. Although the performance of these rubidium frequency standards has met and even exceeded GPS requirements, their reliability has not. The number of unscheduled outage times and the short operational lifetimes of the rubidium frequency standards compare poorly to the track record of the cesium frequency standards. Only a small number of rubidium frequency standards have actually been made operational. Of these, a large percentage have exhibited poor reliability. If this trend continues, it is unlikely that the rubidium frequency standards will help contribute to the navigation payload meeting program specification.

  11. Automatic Locking of Laser Frequency to an Absorption Peak

    Science.gov (United States)

    Koch, Grady J.

    2006-01-01

    An electronic system adjusts the frequency of a tunable laser, eventually locking the frequency to a peak in the optical absorption spectrum of a gas (or of a Fabry-Perot cavity that has an absorption peak like that of a gas). This system was developed to enable precise locking of the frequency of a laser used in differential absorption LIDAR measurements of trace atmospheric gases. This system also has great commercial potential as a prototype of means for precise control of frequencies of lasers in future dense wavelength-division-multiplexing optical communications systems. The operation of this system is completely automatic: Unlike in the operation of some prior laser-frequency-locking systems, there is ordinarily no need for a human operator to adjust the frequency manually to an initial value close enough to the peak to enable automatic locking to take over. Instead, this system also automatically performs the initial adjustment. The system (see Figure 1) is based on a concept of (1) initially modulating the laser frequency to sweep it through a spectral range that includes the desired absorption peak, (2) determining the derivative of the absorption peak with respect to the laser frequency for use as an error signal, (3) identifying the desired frequency [at the very top (which is also the middle) of the peak] as the frequency where the derivative goes to zero, and (4) thereafter keeping the frequency within a locking range and adjusting the frequency as needed to keep the derivative (the error signal) as close as possible to zero. More specifically, the system utilizes the fact that in addition to a zero crossing at the top of the absorption peak, the error signal also closely approximates a straight line in the vicinity of the zero crossing (see Figure 2). This vicinity is the locking range because the linearity of the error signal in this range makes it useful as a source of feedback for a proportional + integral + derivative control scheme that

  12. Optimization of Natural Frequencies and Sound Power of Beams Using Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Nabeel T. Alshabatat

    2014-01-01

    Full Text Available This paper presents a design method to optimize the material distribution of functionally graded beams with respect to some vibration and acoustic properties. The change of the material distribution through the beam length alters the stiffness and the mass of the beam. This can be used to alter a specific beam natural frequency. It can also be used to reduce the sound power radiated from the vibrating beam. Two novel volume fraction laws are used to describe the material volume distributions through the length of the FGM beam. The proposed method couples the finite element method (for the modal and harmonic analysis, Lumped Parameter Model (for calculating the power of sound radiation, and an optimization technique based on Genetic Algorithm. As a demonstration of this technique, the optimization procedure is applied to maximize the fundamental frequency of FGM cantilever and clamped beams and to minimize the sound radiation from vibrating clamped FGM beam at a specific frequency.

  13. Quantitative interpretation of the magnetic susceptibility frequency dependence

    Science.gov (United States)

    Ustra, Andrea; Mendonça, Carlos A.; Leite, Aruã; Jovane, Luigi; Trindade, Ricardo I. F.

    2018-05-01

    Low-field mass-specific magnetic susceptibility (MS) measurements using multifrequency alternating fields are commonly used to evaluate concentration of ferrimagnetic particles in the transition of superparamagnetic (SP) to stable single domain (SSD). In classical palaeomagnetic analyses, this measurement serves as a preliminary assessment of rock samples providing rapid, non-destructive, economical and easy information of magnetic properties. The SP-SSD transition is relevant in environmental studies because it has been associated with several geological and biogeochemical processes affecting magnetic mineralogy. MS is a complex function of mineral-type and grain-size distribution, as well as measuring parameters such as external field magnitude and frequency. In this work, we propose a new technique to obtain quantitative information on grain-size variations of magnetic particles in the SP-SSD transition by inverting frequency-dependent susceptibility. We introduce a descriptive parameter named as `limiting frequency effect' that provides an accurate estimation of MS loss with frequency. Numerical simulations show the methodology capability in providing data fitting and model parameters in many practical situations. Real-data applications with magnetite nanoparticles and core samples from sediments of Poggio le Guaine section of Umbria-Marche Basin (Italy) provide additional information not clearly recognized when interpreting cruder MS data. Caution is needed when interpreting frequency dependence in terms of single relaxation processes, which are not universally applicable and depend upon the nature of magnetic mineral in the material. Nevertheless, the proposed technique is a promising tool for SP-SSD content analyses.

  14. Robust k-mer frequency estimation using gapped k-mers.

    Science.gov (United States)

    Ghandi, Mahmoud; Mohammad-Noori, Morteza; Beer, Michael A

    2014-08-01

    Oligomers of fixed length, k, commonly known as k-mers, are often used as fundamental elements in the description of DNA sequence features of diverse biological function, or as intermediate elements in the constuction of more complex descriptors of sequence features such as position weight matrices. k-mers are very useful as general sequence features because they constitute a complete and unbiased feature set, and do not require parameterization based on incomplete knowledge of biological mechanisms. However, a fundamental limitation in the use of k-mers as sequence features is that as k is increased, larger spatial correlations in DNA sequence elements can be described, but the frequency of observing any specific k-mer becomes very small, and rapidly approaches a sparse matrix of binary counts. Thus any statistical learning approach using k-mers will be susceptible to noisy estimation of k-mer frequencies once k becomes large. Because all molecular DNA interactions have limited spatial extent, gapped k-mers often carry the relevant biological signal. Here we use gapped k-mer counts to more robustly estimate the ungapped k-mer frequencies, by deriving an equation for the minimum norm estimate of k-mer frequencies given an observed set of gapped k-mer frequencies. We demonstrate that this approach provides a more accurate estimate of the k-mer frequencies in real biological sequences using a sample of CTCF binding sites in the human genome.

  15. Remodeling sensory cortical maps implants specific behavioral memory.

    Science.gov (United States)

    Bieszczad, K M; Miasnikov, A A; Weinberger, N M

    2013-08-29

    Neural mechanisms underlying the capacity of memory to be rich in sensory detail are largely unknown. A candidate mechanism is learning-induced plasticity that remodels the adult sensory cortex. Here, expansion in the primary auditory cortical (A1) tonotopic map of rats was induced by pairing a 3.66-kHz tone with activation of the nucleus basalis, mimicking the effects of natural associative learning. Remodeling of A1 produced de novo specific behavioral memory, but neither memory nor plasticity was consistently at the frequency of the paired tone, which typically decreased in A1 representation. Rather, there was a specific match between individual subjects' area of expansion and the tone that was strongest in each animal's memory, as determined by post-training frequency generalization gradients. These findings provide the first demonstration of a match between the artificial induction of specific neural representational plasticity and artificial induction of behavioral memory. As such, together with prior and present findings for detection, correlation and mimicry of plasticity with the acquisition of memory, they satisfy a key criterion for neural substrates of memory. This demonstrates that directly remodeling sensory cortical maps is sufficient for the specificity of memory formation. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. A Novel Frequency Measurement Method Suitable for a Large Frequency Ratio Condition

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wei; XUAN Zong-Qiang; YU Jian-Guo; WANG Hai; ZHOU Hui; LI Zhi-Qi

    2004-01-01

    @@ As for the obstacles to direct comparison between superhigh and lower frequencies, we accomplish the accurate comparison between low and microwave frequencies with the 105 ratios of the operating frequencies on the basis of phase comparison between the signals whose frequencies are related by an arbitrary integer. This method is simple and accurate, and will be widely used as a special frequency comparison approach.

  17. Analysis of Broad-band Frequency Selective Shielding Glass by FDTD method

    OpenAIRE

    笠嶋, 善憲; Kasashima, Yoshinori

    2010-01-01

    A frequency Selective shielding (FSS) glass is a print of many same size antennas on a sheet of glass, and it has high shielding properties for one specific frequency. In the past, the author analyzed theoretically the characteristics of the FSS, as a large scale array antenna. The FSS has narrow-band shielding characteristics. This time, the author analyzed accurately the characteristics of a FSS glass being a print of many same size dipole antennas on a sheet of glass by FDTD method. As the...

  18. Experimental investigation of the effects of high-frequency electroactive morphing on the shear-layer

    Science.gov (United States)

    Scheller, Johannes; Rizzo, Karl-Joseph; Jodin, Gurvan; Duhayon, Eric; Rouchon, Jean-François; Hunt, Julian; Braza, Marianna

    2015-11-01

    Time-resolved PIV measurements are conducted at a Reynolds number of 270 . 000 downstream of the trailing edge of a NACA4412 airfoil equipped with trailing-edge piezoelectric tab actuators to investigate the high-frequency low-amplitude actuation's effect on the shear-layer. A comparison of the time-averaged Reynolds stress tensor components at different actuation frequency reveals a significant impact of the actuation on the shear-layer dynamics. A proper orthogonal decomposition analysis is conducted in order to investigate the actuation's impact on the vortex breakdown. It will be shown that a specific low-amplitude actuation frequency enables a reduction of the predominant shear-layer frequencies.

  19. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-01-01

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected

  20. A Study of Frequency Mixing Approaches for Eddy Current Testing of Steam Generator Tubes

    International Nuclear Information System (INIS)

    Jung, Hee Jun; Song, Sung Jin; Kim, Chang Hwan; Kim, Dae Kwang

    2009-01-01

    The multifrequency eddy current testing(ECT) have been proposed various frequency mixing algorithms. In this study, we compare these approaches to frequency mixing of ECT signals from steam generator tubes; time-domain optimization, discrete cosine transform-domain optimization. Specifically, in this study, two different frequency mixing algorithms, a time-domain optimization method and a discrete cosine transform(DCT) optimization method, are investigated using the experimental signals captured from the ASME standard tube. The DCT domain optimization method is computationally fast but produces larger amount of residue.

  1. Chapter 18: Variable Frequency Drive Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

    Energy Technology Data Exchange (ETDEWEB)

    Romberger, Jeff [SBW Consulting, Inc., Bellevue, WA (United States)

    2017-06-21

    An adjustable-speed drive (ASD) includes all devices that vary the speed of a rotating load, including those that vary the motor speed and linkage devices that allow constant motor speed while varying the load speed. The Variable Frequency Drive Evaluation Protocol presented here addresses evaluation issues for variable-frequency drives (VFDs) installed on commercial and industrial motor-driven centrifugal fans and pumps for which torque varies with speed. Constant torque load applications, such as those for positive displacement pumps, are not covered by this protocol.

  2. Direct measurement of the poliovirus RNA polymerase error frequency in vitro

    International Nuclear Information System (INIS)

    Ward, C.D.; Stokes, M.A.M.; Flanegan, J.B.

    1988-01-01

    The fidelity of RNA replication by the poliovirus-RNA-dependent RNA polymerase was examined by copying homopolymeric RNA templates in vitro. The poliovirus RNA polymerase was extensively purified and used to copy poly(A), poly(C), or poly(I) templates with equimolar concentrations of noncomplementary and complementary ribonucleotides. The error frequency was expressed as the amount of a noncomplementary nucleotide incorporated divided by the total amount of complementary and noncomplementary nucleotide incorporated. The polymerase error frequencies were very high, depending on the specific reaction conditions. The activity of the polymerase on poly(U) and poly(G) was too low to measure error frequencies on these templates. A fivefold increase in the error frequency was observed when the reaction conditions were changed from 3.0 mM Mg 2+ (pH 7.0) to 7.0 mM Mg 2+ (pH 8.0). This increase in the error frequency correlates with an eightfold increase in the elongation rate that was observed under the same conditions in a previous study

  3. Frequency Selection for Multi-frequency Acoustic Measurement of Suspended Sediment

    Science.gov (United States)

    Chen, X.; HO, H.; Fu, X.

    2017-12-01

    Multi-frequency acoustic measurement of suspended sediment has found successful applications in marine and fluvial environments. Difficult challenges remain in regard to improving its effectiveness and efficiency when applied to high concentrations and wide size distributions in rivers. We performed a multi-frequency acoustic scattering experiment in a cylindrical tank with a suspension of natural sands. The sands range from 50 to 600 μm in diameter with a lognormal size distribution. The bulk concentration of suspended sediment varied from 1.0 to 12.0 g/L. We found that the commonly used linear relationship between the intensity of acoustic backscatter and suspended sediment concentration holds only at sufficiently low concentrations, for instance below 3.0 g/L. It fails at a critical value of concentration that depends on measurement frequency and the distance between the transducer and the target point. Instead, an exponential relationship was found to work satisfactorily throughout the entire range of concentration. The coefficient and exponent of the exponential function changed, however, with the measuring frequency and distance. Considering the increased complexity of inverting the concentration values when an exponential relationship prevails, we further analyzed the relationship between measurement error and measuring frequency. It was also found that the inversion error may be effectively controlled within 5% if the frequency is properly set. Compared with concentration, grain size was found to heavily affect the selection of optimum frequency. A regression relationship for optimum frequency versus grain size was developed based on the experimental results.

  4. Exploring the time-frequency content of high frequency oscillations for automated identification of seizure onset zone in epilepsy.

    Science.gov (United States)

    Liu, Su; Sha, Zhiyi; Sencer, Altay; Aydoseli, Aydin; Bebek, Nerse; Abosch, Aviva; Henry, Thomas; Gurses, Candan; Ince, Nuri Firat

    2016-04-01

    High frequency oscillations (HFOs) in intracranial electroencephalography (iEEG) recordings are considered as promising clinical biomarkers of epileptogenic regions in the brain. The aim of this study is to improve and automatize the detection of HFOs by exploring the time-frequency content of iEEG and to investigate the seizure onset zone (SOZ) detection accuracy during the sleep, awake and pre-ictal states in patients with epilepsy, for the purpose of assisting the localization of SOZ in clinical practice. Ten-minute iEEG segments were defined during different states in eight patients with refractory epilepsy. A three-stage algorithm was implemented to detect HFOs in these segments. First, an amplitude based initial detection threshold was used to generate a large pool of HFO candidates. Then distinguishing features were extracted from the time and time-frequency domain of the raw iEEG and used with a Gaussian mixture model clustering to isolate HFO events from other activities. The spatial distribution of HFO clusters was correlated with the seizure onset channels identified by neurologists in seven patient with good surgical outcome. The overlapping rates of localized channels and seizure onset locations were high in all states. The best result was obtained using the iEEG data during sleep, achieving a sensitivity of 81%, and a specificity of 96%. The channels with maximum number of HFOs identified epileptogenic areas where the seizures occurred more frequently. The current study was conducted using iEEG data collected in realistic clinical conditions without channel pre-exclusion. HFOs were investigated with novel features extracted from the entire frequency band, and were correlated with SOZ in different states. The results indicate that automatic HFO detection with unsupervised clustering methods exploring the time-frequency content of raw iEEG can be efficiently used to identify the epileptogenic zone with an accurate and efficient manner.

  5. Spectral and spectral-frequency methods of investigating atmosphereless bodies of the Solar system

    International Nuclear Information System (INIS)

    Busarev, Vladimir V; Prokof'eva-Mikhailovskaya, Valentina V; Bochkov, Valerii V

    2007-01-01

    A method of reflectance spectrophotometry of atmosphereless bodies of the Solar system, its specificity, and the means of eliminating basic spectral noise are considered. As a development, joining the method of reflectance spectrophotometry with the frequency analysis of observational data series is proposed. The combined spectral-frequency method allows identification of formations with distinctive spectral features, and estimations of their sizes and distribution on the surface of atmospherelss celestial bodies. As applied to investigations of asteroids 21 Lutetia and 4 Vesta, the spectral frequency method has given us the possibility of obtaining fundamentally new information about minor planets. (instruments and methods of investigation)

  6. Use of high throughput qPCR screening to rapidly clone low frequency tumour specific T-cells from peripheral blood for adoptive immunotherapy

    Directory of Open Access Journals (Sweden)

    Serrano Oscar K

    2008-10-01

    Full Text Available Abstract Background The adoptive transfer of autologous tumor reactive lymphocytes can mediate significant tumor regression in some patients with refractory metastatic cancer. However, a significant obstacle for this promising therapy has been the availability of highly efficient methods to rapidly isolate and expand a variety of potentially rare tumor reactive lymphocytes from the natural repertoire of cancer patients. Methods We developed a novel in vitro T cell cloning methodology using high throughput quantitative RT-PCR (qPCR assay as a rapid functional screen to detect and facilitate the limiting dilution cloning of a variety of low frequency T cells from bulk PBMC. In preclinical studies, this strategy was applied to the isolation and expansion of gp100 specific CD8+ T cell clones from the peripheral blood of melanoma patients. Results In optimization studies, the qPCR assay could detect the reactivity of 1 antigen specific T cell in 100,000 background cells. When applied to short term sensitized PBMC microcultures, this assay could detect T cell reactivity against a variety of known melanoma tumor epitopes. This screening was combined with early limiting dilution cloning to rapidly isolate gp100154–162 reactive CD8+ T cell clones. These clones were highly avid against peptide pulsed targets and melanoma tumor lines. They had an effector memory phenotype and showed significant proliferative capacity to reach cell numbers appropriate for adoptive transfer trials (~1010 cells. Conclusion This report describes a novel high efficiency strategy to clone tumor reactive T cells from peripheral blood for use in adoptive immunotherapy.

  7. On-electrode autonomous current generator for multi-frequency EIT

    International Nuclear Information System (INIS)

    Jivet, I; Dragoi, B

    2008-01-01

    The paper presents an autonomous programmable current generator module for multi-frequency EIT systems. The module incorporates all stages from the sine wave generation with frequency and amplitude tuning, D/A converter and filter, a high output resistance voltage-to-current converter to the associated digital communication and control. The paper presents in depth the original digital quadrature signal generator and the output current generator with a high resistance. The other main blocks of the design use current practice specifications, since recent technological solutions proposed in the literature were found appropriate. The proposed signal generator circuit, characterized by a very low complexity, is analyzed in its capacity to produce multiple accurate signals up to 1 MHz in frequency. The precision output current source uses a modified current conveyor of type CCII with a high output resistance and low distortion. The output current frequency spectrum and linearity parameters obtained in the simulations are also described. The simulation results indicate a good linearity and high output resistance with an acceptable output voltage swing. The calculated performance parameters are validated with simulations, and future work for the prototype fabrication of the IC is outlined

  8. Multivariate Frequency-Severity Regression Models in Insurance

    Directory of Open Access Journals (Sweden)

    Edward W. Frees

    2016-02-01

    Full Text Available In insurance and related industries including healthcare, it is common to have several outcome measures that the analyst wishes to understand using explanatory variables. For example, in automobile insurance, an accident may result in payments for damage to one’s own vehicle, damage to another party’s vehicle, or personal injury. It is also common to be interested in the frequency of accidents in addition to the severity of the claim amounts. This paper synthesizes and extends the literature on multivariate frequency-severity regression modeling with a focus on insurance industry applications. Regression models for understanding the distribution of each outcome continue to be developed yet there now exists a solid body of literature for the marginal outcomes. This paper contributes to this body of literature by focusing on the use of a copula for modeling the dependence among these outcomes; a major advantage of this tool is that it preserves the body of work established for marginal models. We illustrate this approach using data from the Wisconsin Local Government Property Insurance Fund. This fund offers insurance protection for (i property; (ii motor vehicle; and (iii contractors’ equipment claims. In addition to several claim types and frequency-severity components, outcomes can be further categorized by time and space, requiring complex dependency modeling. We find significant dependencies for these data; specifically, we find that dependencies among lines are stronger than the dependencies between the frequency and average severity within each line.

  9. LOW FREQUENCY DAMPER

    Directory of Open Access Journals (Sweden)

    Radu BOGATEANU

    2009-09-01

    Full Text Available The low frequency damper is an autonomous equipment for damping vibrations with the 1-20Hz range.Its autonomy enables the equipment to be located in various mechanical systems, without requiring special hydraulic installations.The low frequency damper was designed for damping the low frequency oscillations occurring in the circuit controls of the upgraded IAR-99 Aircraft.The low frequency damper is a novelty in the aerospace field ,with applicability in several areas as it can be built up in an appropriate range of dimensions meeting the requirements of different beneficiaries. On this line an equipment able to damp an extended frequency range was performed for damping oscillations in the pipes of the nuclear power plants.This damper, tested in INCAS laboratories matched the requirements of the beneficiary.The low frequency damper is patented – the patent no. 114583C1/2000 is held by INCAS.

  10. Improvements to Technical Specifications surveillance requirements

    International Nuclear Information System (INIS)

    Lobel, R.; Tjader, T.R.

    1992-12-01

    In August 1983 an NRC task group was formed to investigate problems with surveillance testing required by Technical Specifications, and to recommend approaches to effect improvements. NUREG-1024 (''Technical Specifications-Enhancing Safety Impact'') resulted, and it contained recommendations to review the basis for test frequencies; to ensure that the tests promote safety and do not degrade equipment; and to review surveillance tests so that they do not unnecessarily burden personnel. The Technical Specifications Improvement Program (TSIP) was established in December 1984 to provide the framework for rewriting and improving the Technical Specifications. As an element of the TSIP, all Technical Specifications surveillance requirements were comprehensively examined as recommended in NUREG-1024. The results of that effort are presented in this report. The study found that while some testing at power is essential to verify equipment and system operability, safety can be improved, equipment degradation decreased, and unnecessary personnel burden relaxed by reducing the amount of testing at power

  11. 47 CFR 90.267 - Assignment and use of frequencies in the 450-470 MHz band for low power use.

    Science.gov (United States)

    2010-10-01

    ...-470 MHz band for low power use. 90.267 Section 90.267 Telecommunication FEDERAL COMMUNICATIONS... Special Frequencies or Frequency Bands § 90.267 Assignment and use of frequencies in the 450-470 MHz band... medical radio telemetry device with an output power not to exceed 20 milliwatts without specific...

  12. Relative validity of the geisinger rural aging study food frequency questionniare

    Science.gov (United States)

    Objective: To determine the relative validity of a population specific food frequency questionnaire (FFQ) and evaluate the effectiveness of the instrument for assessing nutritional risk in older adults. Design: A cross-over design with participants completing two different dietary assessment inst...

  13. Electron heating mode transition induced by mixing radio frequency and ultrahigh frequency dual frequency powers in capacitive discharges

    International Nuclear Information System (INIS)

    Sahu, B. B.; Han, Jeon G.

    2016-01-01

    Electron heating mode transitions induced by mixing the low- and high-frequency power in dual-frequency nitrogen discharges at 400 mTorr pressure are presented. As the low-frequency (13.56 MHz) power decreases and high-frequency (320 MHz) power increases for the fixed power of 200 W, there is a transition of electron energy distribution function (EEDF) from Druyvesteyn to bi-Maxwellian type characterized by a distinguished warm electron population. It is shown that this EEDF evolution is attributed to the transition from collisional to collisionless stochastic heating of the low-energy electrons.

  14. Adolescent Sexual Behaviors at Varying Levels of Substance Use Frequency

    Science.gov (United States)

    Floyd, Leah J.; Latimer, William

    2010-01-01

    Combining substance use and sex compounds the risk of contracting sexually transmitted diseases, including HIV. However, the association between substance use and sexual behaviors may vary by substance and sexual behavior. The current study sought to examine the relationship between alcohol and marijuana use frequency and specific sexual…

  15. High-frequency measurements of aeolian saltation flux: Field-based methodology and applications

    Science.gov (United States)

    Martin, Raleigh L.; Kok, Jasper F.; Hugenholtz, Chris H.; Barchyn, Thomas E.; Chamecki, Marcelo; Ellis, Jean T.

    2018-02-01

    Aeolian transport of sand and dust is driven by turbulent winds that fluctuate over a broad range of temporal and spatial scales. However, commonly used aeolian transport models do not explicitly account for such fluctuations, likely contributing to substantial discrepancies between models and measurements. Underlying this problem is the absence of accurate sand flux measurements at the short time scales at which wind speed fluctuates. Here, we draw on extensive field measurements of aeolian saltation to develop a methodology for generating high-frequency (up to 25 Hz) time series of total (vertically-integrated) saltation flux, namely by calibrating high-frequency (HF) particle counts to low-frequency (LF) flux measurements. The methodology follows four steps: (1) fit exponential curves to vertical profiles of saltation flux from LF saltation traps, (2) determine empirical calibration factors through comparison of LF exponential fits to HF number counts over concurrent time intervals, (3) apply these calibration factors to subsamples of the saltation count time series to obtain HF height-specific saltation fluxes, and (4) aggregate the calibrated HF height-specific saltation fluxes into estimates of total saltation fluxes. When coupled to high-frequency measurements of wind velocity, this methodology offers new opportunities for understanding how aeolian saltation dynamics respond to variability in driving winds over time scales from tens of milliseconds to days.

  16. High-frequency resistance training is not more effective than low-frequency resistance training in increasing muscle mass and strength in well-trained men.

    Science.gov (United States)

    Gomes, Gederson K; Franco, Cristiane M; Nunes, Paulo Ricardo P; Orsatti, Fábio L

    2018-02-27

    We studied the effects of two different weekly frequency resistance training (RT) protocols over eight weeks on muscle strength and muscle hypertrophy in well-trained men. Twenty-three subjects (age: 26.2±4.2 years; RT experience: 6.9±3.1 years) were randomly allocated into the two groups: low frequency (LFRT, n = 12) or high frequency (HFRT, n = 11). The LFRT performed a split-body routine, training each specific muscle group once a week. The HFRT performed a total-body routine, training all muscle groups every session. Both groups performed the same number of sets (10-15 sets) and exercises (1-2 exercise) per week, 8-12 repetitions maximum (70-80% of 1RM), five times per week. Muscle strength (bench press and squat 1RM) and lean tissue mass (dual-energy x-ray absorptiometry) were assessed prior to and at the end of the study. Results showed that both groups improved (ptrained subjects when the sets and intensity are equated per week.

  17. Memory Processes in Frequency Judgment: The impact of pre-experimental frequencies and co-occurrences on frequency estimates.

    OpenAIRE

    Renkewitz, Frank

    2004-01-01

    Contemporary theories on frequency processing have been developed in different sub-disciplines of psychology and have shown remarkable discrepancies. Thus, in judgment and decision making, frequency estimates on serially encoded events are mostly traced back to the availability heuristic (Tversky & Kahneman, 1973). Evidence for the use of this heuristic comes from several popular demonstrations of biased frequency estimates. In the area of decision making, these demonstrations led to the ...

  18. In-situ identification of marine organisms using high frequency, wideband ultrasound

    DEFF Research Database (Denmark)

    Pham, An Hoai

    methods. Conventional acoustical methods use frequencies in the range of 10 to 500 kHz and give reasonable estimations of size distribution, if the species is known, but can only significantly support the determination of the actual species, if there are only a few known species available. It is expected...... that higher frequencies and broader bandwidths than used until now will give more information useful for fish species identification. The objective of this Ph.D. study has been to develop a method to investigate the possibility of in-situ identification of fish with high-frequency, wideband ultrasound...... and the fish bodies. The frequencies are 2, 3.5, and 6 MHz. The angles are -30°, -15°, 0°, 15°, and 30°. The results show that even though there are variations, a scan of the ultrasound backscatter along a fish of a specific species contains patterns that are characteristic for that species. This is true...

  19. Vibration Isolation Study in Scanning Probe Microscopy Part I: Low Frequency

    International Nuclear Information System (INIS)

    Oliva, A.I.; Espinosa-Faller, F.J.; Aguilar, M.

    1998-01-01

    A study of a low frequency isolation device based in a pneumatic system is presented. It consists of four cylinders which are closed and sealed with an elastic membrane on which the load is applied. Each cylinder made of PVC is formed by two chambers divided by a plate with a small hole for communication and damping. Air contained into chambers acts, in combination with the the elastic membranes, as a damper. Scanning probe techniques can be supported by this device in order to reduce the low frequency noises that affects them. Advantages of this isolator are discussed and compared. A theoretical approximation for this model is presented and compared with the experimental results obtained and show that it can isolate noises up to ∼ 2 Hz. The low frequency isolator has stability and fast response to external perturbations. This simple and economical low frequency isolator can be reproduced easily and its design depends on the work specific requirements. (Author) 9 refs

  20. Identification of two-phase flow pattern by using specific spatial frequency of differential pressure signal

    International Nuclear Information System (INIS)

    Han Bin; Tong Yunxian; Wu Shaorong

    1992-11-01

    It is a classical method by using analysis of differential pressure fluctuation signal to identify two-phase flow pattern. The method which uses trait peak in the frequency-domain will result confusion between bubble flow and intermittent flow due to the influence of gas speed. Considering the spatial geometric significance of two-phase slow patterns and using the differential pressure gauge as a sensor, the Strouhal number 'Sr' is taken as the basis for distinguishing flow patterns. Using Strouhal number 'Sr' to identify flow pattern has clear physical meaning. The experimental results using the spatial analytical technique to measure the flow pattern are also given

  1. Nonlinear gyrokinetic equations for low-frequency electromagnetic waves in general plasma equilibria

    International Nuclear Information System (INIS)

    Frieman, E.A.; Chen, L.

    1981-10-01

    A nonlinear gyrokinetic formalism for low-frequency (less than the cyclotron frequency) microscopic electromagnetic perturbations in general magnetic field configurations is developed. The nonlinear equations thus derived are valid in the strong-turbulence regime and contain effects due to finite Larmor radius, plasma inhomogeneities, and magentic field geometries. The specific case of axisymmetric tokamaks is then considered, and a model nonlinear equation is derived for electrostatic drift waves. Also, applying the formalism to the shear Alfven wave heating sceme, it is found that nonlinear ion Landau damping of kinetic shear-Alfven waves is modified, both qualitatively and quantitatively, by the diamagnetic drift effects. In particular, wave energy is found to cascade in wavenumber instead of frequency

  2. Efficient molecular screening of Lynch syndrome by specific 3' promoter methylation of the MLH1 or BRAF mutation in colorectal cancer with high-frequency microsatellite instability.

    Science.gov (United States)

    Nakagawa, Hitoshi; Nagasaka, Takeshi; Cullings, Harry M; Notohara, Kenji; Hoshijima, Naoko; Young, Joanne; Lynch, Henry T; Tanaka, Noriaki; Matsubara, Nagahide

    2009-06-01

    It is sometimes difficult to diagnose Lynch syndrome by the simple but strict clinical criteria, or even by the definitive genetic testing for causative germline mutation of mismatch repair genes. Thus, some practical and efficient screening strategy to select highly possible Lynch syndrome patients is exceedingly desirable. We performed a comprehensive study to evaluate the methylation status of whole MLH1 promoter region by direct bisulfite sequencing of the entire MLH1 promoter regions on Lynch and non-Lynch colorectal cancers (CRCs). Then, we established a convenient assay to detect methylation in key CpG islands responsible for the silencing of MLH1 expression. We studied the methylation status of MLH1 as well as the CpG island methylator phenotype (CIMP) and immunohistochemical analysis of mismatch repair proteins on 16 cases of Lynch CRC and 19 cases of sporadic CRCs with high-frequency microsatellite instability (MSI-H). Sensitivity to detect Lynch syndrome by MLH1 (CCAAT) methylation was 88% and the specificity was 84%. Positive likelihood ratio (PLR) was 5.5 and negative likelihood ratio (NLR) was 0.15. Sensitivity by mutational analysis of BRAF was 100%, specificity was 84%, PLR was 6.3 and NLR was zero. By CIMP analysis; sensitivity was 88%, specificity was 79%, PLR was 4.2, and NLR was 0.16. BRAF mutation or MLH1 methylation analysis combined with MSI testing could be a good alternative to screen Lynch syndrome patients in a cost effective manner. Although the assay for CIMP status also showed acceptable sensitivity and specificity, it may not be practical because of its rather complicated assay.

  3. Controllable frequency entanglement via auto-phase-matched spontaneous parametric down-conversion

    International Nuclear Information System (INIS)

    Sergienko, A.V.; Walton, Z.D.; Booth, M.C.; Saleh, B.E.A.; Teich, M.C.

    2005-01-01

    Full text: A new method for generating entangled photons with controllable frequency correlation via spontaneous parametric down-conversion (SPDC) is presented. The method entails initiating counter-propagating SPDC in a single-mode nonlinear waveguide by pumping with a pulsed beam perpendicular to the waveguide. In a typical spontaneous parametric down-conversion (SPDC) experiment, a photon from a monochromatic pump beam decays into two photons (often referred to as signal and idler) via interaction with a nonlinear optical crystal. While the signal and idler may be broadband individually, conservation of energy requires that the sum of their respective frequencies equals the single frequency of the monochromatic pump. This engenders frequency anti-correlation in the down-converted beams. Two developments in quantum information theory have renewed interest in the generalized states of frequency correlation. First, quantum information processes requiring the synchronized creation of multiple photon pairs have been devised, such as quantum teleportation. The requisite temporal control can be achieved by pumping the crystal with a brief pulse. The availability of pump photons of differing frequencies relaxes the strict frequency anti-correlation in the down-converted beams. Second, applications such as entanglement-enhanced clock synchronization and one-way auto-compensating quantum cryptography have been introduced that specifically require frequency correlation, as opposed to the usual frequency anticorrelation. Our method for obtaining controllable frequency entanglement entails initiating type-I SPDC (signal and idler identically polarized) in a single-mode nonlinear waveguide by pumping with a pulsed beam perpendicular to the waveguide. The down-converted photons emerge from opposite ends of the waveguide with a joint spectrum that can be varied from frequency anti-correlated to frequency correlated by adjusting the temporal and spatial characteristics of the

  4. Dipeptide frequency/bias analysis identifies conserved sites of nonrandomness shared by cysteine-rich motifs.

    Science.gov (United States)

    Campion, S R; Ameen, A S; Lai, L; King, J M; Munzenmaier, T N

    2001-08-15

    This report describes the application of a simple computational tool, AAPAIR.TAB, for the systematic analysis of the cysteine-rich EGF, Sushi, and Laminin motif/sequence families at the two-amino acid level. Automated dipeptide frequency/bias analysis detects preferences in the distribution of amino acids in established protein families, by determining which "ordered dipeptides" occur most frequently in comprehensive motif-specific sequence data sets. Graphic display of the dipeptide frequency/bias data revealed family-specific preferences for certain dipeptides, but more importantly detected a shared preference for employment of the ordered dipeptides Gly-Tyr (GY) and Gly-Phe (GF) in all three protein families. The dipeptide Asn-Gly (NG) also exhibited high-frequency and bias in the EGF and Sushi motif families, whereas Asn-Thr (NT) was distinguished in the Laminin family. Evaluation of the distribution of dipeptides identified by frequency/bias analysis subsequently revealed the highly restricted localization of the G(F/Y) and N(G/T) sequence elements at two separate sites of extreme conservation in the consensus sequence of all three sequence families. The similar employment of the high-frequency/bias dipeptides in three distinct protein sequence families was further correlated with the concurrence of these shared molecular determinants at similar positions within the distinctive scaffolds of three structurally divergent, but similarly employed, motif modules.

  5. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  6. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  7. Mutual Information in Frequency and Its Application to Measure Cross-Frequency Coupling in Epilepsy

    Science.gov (United States)

    Malladi, Rakesh; Johnson, Don H.; Kalamangalam, Giridhar P.; Tandon, Nitin; Aazhang, Behnaam

    2018-06-01

    We define a metric, mutual information in frequency (MI-in-frequency), to detect and quantify the statistical dependence between different frequency components in the data, referred to as cross-frequency coupling and apply it to electrophysiological recordings from the brain to infer cross-frequency coupling. The current metrics used to quantify the cross-frequency coupling in neuroscience cannot detect if two frequency components in non-Gaussian brain recordings are statistically independent or not. Our MI-in-frequency metric, based on Shannon's mutual information between the Cramer's representation of stochastic processes, overcomes this shortcoming and can detect statistical dependence in frequency between non-Gaussian signals. We then describe two data-driven estimators of MI-in-frequency: one based on kernel density estimation and the other based on the nearest neighbor algorithm and validate their performance on simulated data. We then use MI-in-frequency to estimate mutual information between two data streams that are dependent across time, without making any parametric model assumptions. Finally, we use the MI-in- frequency metric to investigate the cross-frequency coupling in seizure onset zone from electrocorticographic recordings during seizures. The inferred cross-frequency coupling characteristics are essential to optimize the spatial and spectral parameters of electrical stimulation based treatments of epilepsy.

  8. DDC Descriptor Frequencies.

    Science.gov (United States)

    Klingbiel, Paul H.; Jacobs, Charles R.

    This report summarizes the frequency of use of the 7144 descriptors used for indexing technical reports in the Defense Documentation Center (DDC) collection. The descriptors are arranged alphabetically in the first section and by frequency in the second section. The frequency data cover about 427,000 AD documents spanning the interval from March…

  9. Measuring Auditory Selective Attention using Frequency Tagging

    Directory of Open Access Journals (Sweden)

    Hari M Bharadwaj

    2014-02-01

    Full Text Available Frequency tagging of sensory inputs (presenting stimuli that fluctuate periodically at rates to which the cortex can phase lock has been used to study attentional modulation of neural responses to inputs in different sensory modalities. For visual inputs, the visual steady-state response (VSSR at the frequency modulating an attended object is enhanced, while the VSSR to a distracting object is suppressed. In contrast, the effect of attention on the auditory steady-state response (ASSR is inconsistent across studies. However, most auditory studies analyzed results at the sensor level or used only a small number of equivalent current dipoles to fit cortical responses. In addition, most studies of auditory spatial attention used dichotic stimuli (independent signals at the ears rather than more natural, binaural stimuli. Here, we asked whether these methodological choices help explain discrepant results. Listeners attended to one of two competing speech streams, one simulated from the left and one from the right, that were modulated at different frequencies. Using distributed source modeling of magnetoencephalography results, we estimate how spatially directed attention modulates the ASSR in neural regions across the whole brain. Attention enhances the ASSR power at the frequency of the attended stream in the contralateral auditory cortex. The attended-stream modulation frequency also drives phase-locked responses in the left (but not right precentral sulcus (lPCS, a region implicated in control of eye gaze and visual spatial attention. Importantly, this region shows no phase locking to the distracting stream suggesting that the lPCS in engaged in an attention-specific manner. Modeling results that take account of the geometry and phases of the cortical sources phase locked to the two streams (including hemispheric asymmetry of lPCS activity help partly explain why past ASSR studies of auditory spatial attention yield seemingly contradictory

  10. Frequency Response Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    Etingov, Pavel V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kosterev, Dmitry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dai, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

  11. TropFishR: an R package for fisheries analysis with length-frequency data

    DEFF Research Database (Denmark)

    Mildenberger, Tobias; Taylor, M. H.; Wolff, A.M.

    2017-01-01

    1. The R package TropFishR is a new analysis toolbox compiling single-species stock assessment methods specifically designed for data-limited fisheries analysis using length-frequency data. 2. It includes methods for (i) estimating biological stock characteristics such as growth and mortality par...... introduces the package and demonstrates the functionality of a selection of its core methods. 4. TropFishR modernises traditional stock assessment methods by easing application and development and by combining it with advanced statistical approaches......1. The R package TropFishR is a new analysis toolbox compiling single-species stock assessment methods specifically designed for data-limited fisheries analysis using length-frequency data. 2. It includes methods for (i) estimating biological stock characteristics such as growth and mortality...

  12. Low-frequency-noise complaints

    DEFF Research Database (Denmark)

    Pedersen, Christian Sejer; Møller, Henrik; Persson-Waye, Kerstin

    2008-01-01

    From 203 cases of low-frequency complaints a random selection of twenty-one cases were investigated. The main aim of the investigation was to answer the question whether the annoyance is caused by an external physical sound or by a physically non-existing sound, i.e. low-frequency tinnitus. Noise...... of the complainants are annoyed by a physical sound (20-180 Hz), while others suffer from low-frequency tinnitus (perceived frequency 40-100 Hz). Physical sound at frequencies below 20 Hz (infrasound) is not responsible for the annoyance - or at all audible - in any of the investigated cases, and none...... of the complainants has extraordinary hearing sensitivity at low frequencies. For comparable cases of low-frequency noise complaints in general, it is anticipated that physical sound is responsible in a substantial part of the cases, while low-frequency tinnitus is responsible in another substantial part of the cases....

  13. A Novel L-Shape Ultra Wideband Chipless Radio-Frequency Identification Tag

    Directory of Open Access Journals (Sweden)

    Khaled Issa

    2017-01-01

    Full Text Available A novel compact dual-polarized-spectral-signature-based chipless radio-frequency identification (RFID tag is presented. Specifically, an L-shape resonator-based structure is optimized to have different spectral signatures in both horizontal and vertical polarizations, in order to double the encoding capacity. Resonators’ slot width and the space between closely placed resonators are also optimized to enhance the mutual coupling, thereby helping in achieving high-data encoding density. The proposed RFID tag operates over 5 GHz to 10 GHz frequency band. As a proof of concept, three different 18-bit dual-polarized RFID tags are simulated, fabricated, and tested in an anechoic chamber environment. The measurement data show reasonable agreement with the simulation results, with respect to resonators’ frequency positions, null depth, and their bandwidth over the operational spectrum.

  14. The Siren song of vocal fundamental frequency for romantic relationships

    Directory of Open Access Journals (Sweden)

    Sarah eWeusthoff

    2013-07-01

    Full Text Available A multitude of factors contribute to why and how romantic relationships are formed as well as whether they ultimately succeed or fail. Drawing on evolutionary models of attraction and speech production as well as integrative models of relationship functioning, this review argues that paralinguistic cues (more specifically the fundamental frequency of the voice that are initially a strong source of attraction also increase couples’ risk for relationship failure. Conceptual similarities and differences between the multiple operationalizations and interpretations of vocal fundamental frequency are discussed and guidelines are presented for understanding both convergent and non-convergent findings. Implications for clinical practice and future research are discussed.

  15. The siren song of vocal fundamental frequency for romantic relationships.

    Science.gov (United States)

    Weusthoff, Sarah; Baucom, Brian R; Hahlweg, Kurt

    2013-01-01

    A multitude of factors contribute to why and how romantic relationships are formed as well as whether they ultimately succeed or fail. Drawing on evolutionary models of attraction and speech production as well as integrative models of relationship functioning, this review argues that paralinguistic cues (more specifically the fundamental frequency of the voice) that are initially a strong source of attraction also increase couples' risk for relationship failure. Conceptual similarities and differences between the multiple operationalizations and interpretations of vocal fundamental frequency are discussed and guidelines are presented for understanding both convergent and non-convergent findings. Implications for clinical practice and future research are discussed.

  16. FROM STABLE LASERS TO OPTICAL-FREQUENCY CLOCKS:. Merging the UltraFast and the UltraStable, for a New Epoch of Optical Frequency Measurements, Standards, & Applications

    Science.gov (United States)

    Hall, J. L.; Ye, J.; Ma, L.-S.; Peng, J.-L.; Notcutt, M.; Jost, J. D.; Marian, A.

    2002-04-01

    This is a report on behalf of the World Team of Stable Laser and Optical Frequency Measurement Enthusiasts, even if most detailed illustrations draw mainly from our work at JILA. Specifically we trace some of the key ideas that have led from the first stabilized lasers, to frequency measurement up to 88 THz using frequency chains, revision of the Definition of the Metre, extension of coherent frequency chain technology into the visible, development of a vast array of stabilized lasers, and finally the recent explosive growth of direct frequency measurement capability in the visible using fs comb techniques. We present our recent work showing a Molecular Iodine-based Optical Clock which delivers, over a range of time scales, rf output at a stability level basically equivalent to the RF stability prototype, the Hydrogen Maser. We note the bifurcation between single-ion-based clocks - likely to be the stability/reproducibility ultimate winners in the next generation - and simpler systems based on gas cells, which can have impressive stabilities but may suffer from a variety of reproducibility-limiting processes. Active Phase-Lock synchronization of independent fs lasers allows sub-fs timing control. Copies of related works in our labs may be found/obtained at our website .

  17. Efficacy of femtosecond lasers for application of acupuncture therapy.

    Science.gov (United States)

    Ohta, Mika; Hosokawa, Yoichiroh; Hatano, Naoya; Sugano, Aki; Ito, Akihiko; Takaoka, Yutaka

    2017-12-01

    Acupuncture treatment utilizes the stimulation of metal acupuncture needles that are manually inserted into a living body. In the last decades, laser light has been used as an alternative to needles to stimulate acupuncture points. We previously reported suppression of myostatin (Mstn) gene expression in skeletal muscle by means of femtosecond laser (FL) irradiation, after electroacupuncture, in which acupuncture needles are stimulated with a low-frequency microcurrent. The purpose of the study here was to investigate the efficacy of FL irradiation in mouse skeletal muscle with regard to protein synthesis. After irradiation of the hindlimbs, we first analyzed Mstn gene expression and Mstn protein level in the skeletal muscle. We then evaluated phosphorylation of the mammalian target of rapamycin (mTOR) and its downstream target 70-kDa ribosomal protein S6 kinase (p70S6K). The results showed that FL irradiation significantly reduced the amount of Mstn protein and enhanced the phosphorylation of p70S6K in of the mTOR/S6K signaling pathway. We suggest that FL irradiation activated the protein synthetic pathway in the skeletal muscle. In conclusion, we determined that FL irradiation can serve as an alternative for acupuncture needles and has the potential of being a new non-invasive acupuncture treatment of skeletal muscle.

  18. Frequency-dependent changes in the amplitude of low-frequency fluctuations in patients with Wilson's disease: a resting-state fMRI study.

    Science.gov (United States)

    Hu, Xiaopeng; Chen, Siyi; Huang, Chang-Bing; Qian, Yinfeng; Yu, Yongqiang

    2017-06-01

    To investigate the frequency-dependent changes in the amplitude of low-frequency fluctuations (ALFF) in patients with Wilson's disease (WD). Resting-state function magnetic resonance imaging (R-fMRI) were employed to measure the amplitude of ALFF in 28 patients with WD and 27 matched normal controls. Slow-5 (0.01-0.027 Hz) and slow-4 (0.027-0.073 Hz) frequency bands were analyzed. Apart from the observation of atrophy in the cerebellum, basal ganglia, occipital gyrus, frontal gyrus, precentral gyrus, and paracentral lobule, we also found widespread differences in ALFF of the two bands in the medial frontal gyrus, inferior temporal gyrus, insula, basal ganglia, hippocampus/parahippocampal gyrus, and thalamus bilaterally. Compared to normal controls, WD patients had increased ALFF in the posterior lobe of the cerebellum, inferior temporal gyrus, brain stem, basal ganglia, and decreased ALFF in the anterior lobe of the cerebellum and medial frontal gyrus. Specifically, we observed that the ALFF abnormalities in the cerebellum and middle frontal gyrus were greater in the slow-5 than in the slow-4 band. Correlation analysis showed consistently positive correlations between urinary copper excretion (Cu), serum ceruloplasmin (CP) and ALFFs in the cerebellum. Our study suggests the accumulation of copper profoundly impaired intrinsic brain activity and the impairments seem to be frequency-dependent. These results provide further insights into the understanding of the pathophysiology of WD.

  19. Outer hair cell piezoelectricity: frequency response enhancement and resonance behavior.

    Science.gov (United States)

    Weitzel, Erik K; Tasker, Ron; Brownell, William E

    2003-09-01

    Stretching or compressing an outer hair cell alters its membrane potential and, conversely, changing the electrical potential alters its length. This bi-directional energy conversion takes place in the cell's lateral wall and resembles the direct and converse piezoelectric effects both qualitatively and quantitatively. A piezoelectric model of the lateral wall has been developed that is based on the electrical and material parameters of the lateral wall. An equivalent circuit for the outer hair cell that includes piezoelectricity shows a greater admittance at high frequencies than one containing only membrane resistance and capacitance. The model also predicts resonance at ultrasonic frequencies that is inversely proportional to cell length. These features suggest all mammals use outer hair cell piezoelectricity to support the high-frequency receptor potentials that drive electromotility. It is also possible that members of some mammalian orders use outer hair cell piezoelectric resonance in detecting species-specific vocalizations.

  20. Spatial Frequency Discrimination: Effects of Age, Reward, and Practice.

    Directory of Open Access Journals (Sweden)

    Carlijn van den Boomen

    Full Text Available Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed in a higher spatial frequency (reference frequency: 6 cycles per degree discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135. Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5-6 year-olds (N = 28 punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5-6 years completed only a fourth or half of the run (64 to 128 out of 254 trials and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7-12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7-12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be

  1. Spatial Frequency Discrimination: Effects of Age, Reward, and Practice.

    Science.gov (United States)

    van den Boomen, Carlijn; Peters, Judith Carolien

    2017-01-01

    Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed) in a higher spatial frequency (reference frequency: 6 cycles per degree) discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135). Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5-6 year-olds (N = 28) punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5-6 years completed only a fourth or half of the run (64 to 128 out of 254 trials) and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7-12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7-12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be used in future

  2. Components of cross-frequency modulation in health and disease

    Directory of Open Access Journals (Sweden)

    Elena A Allen

    2011-07-01

    Full Text Available The cognitive deficits associated with schizophrenia are commonly believed to arise from the abnormal temporal integration of information, however a quantitative approach to assess network coordination is lacking. Here, we propose to use cross-frequency modulation, the dependence of local high-frequency activity on the phase of widespread low-frequency oscillations, as an indicator of network coordination and functional integration. In an exploratory analysis based on pre-existing data, we measured cross-frequency modulation from multi-channel EEG recordings acquired while schizophrenia patients (n = 47 and healthy controls (n = 130 performed an auditory oddball task. Novel application of independent component analysis (ICA to modulation data delineated components with specific spatial and spectral profiles, the weights of which showed co-variation with diagnosis. Global cross-frequency modulation was significantly greater in healthy controls (F1,175=9.25, P<0.005, while modulation at fronto-temporal electrodes was greater in patients (F1,175 =17.5, P<0.0001. We further found that the weights of schizophrenia-relevant components were associated with genetic polymorphisms at previously identified risk loci. Global cross-frequency modulation decreased with copies of 957C allele in the gene for the dopamine D2 receptor (r = −0.20, P < 0.01 across all subjects. Additionally, greater ‘aberrant’ fronto-temporal modulation in schizophrenia patients was correlated with several polymorphisms in the gene for the α2-subunit of the GABAA receptor (GABRA2 as well as the total number of risk alleles in GABRA2 (r = 0.45, P < 0.01. Overall, our results indicate great promise for this approach in establishing patterns of cross-frequency modulation in health and disease and elucidating the roles of oscillatory interactions in functional connectivity.

  3. Frequency of atopy in the Arctic in 1987 and 1998

    DEFF Research Database (Denmark)

    Krause, Tyra; Koch, Anders; Friborg, Jeppe

    2002-01-01

    atopy as a positive result in an assay that tests for specific IgE against the eight most common inhalant allergens in one pool (grass, birch, mugwort, dog, cat, horse, Cladosporum herbarum, house dust mite). The frequency of atopy doubled between 1987 (39 [10%] of 392) and 1998 (87 [19%] of 467; risk...

  4. Compact frequency-modulation Q-switched single-frequency fiber laser at 1083 nm

    International Nuclear Information System (INIS)

    Zhang, Yuanfei; Feng, Zhouming; Xu, Shanhui; Mo, Shupei; Yang, Changsheng; Li, Can; Gan, Jiulin; Chen, Dongdan; Yang, Zhongmin

    2015-01-01

    A compact frequency-modulation Q-switched single-frequency fiber laser is demonstrated at 1083 nm. The short linear resonant cavity consists of a 12 mm long homemade Yb 3+ -doped phosphate fiber and a pair of fiber Bragg gratings (FBGs) in which the Q-switching and the frequency excursion is achieved by a tensile-induced period modulation. Over 375 MHz frequency-tuning range is achieved with a modulation frequency varying from tens to hundreds of kilohertz. The highest peak power of the output pulse reaching 6.93 W at the repetition rate of 10 kHz is obtained. (paper)

  5. Analysis of the Extremely Low Frequency Magnetic Field Emission from Laptop Computers

    Directory of Open Access Journals (Sweden)

    Brodić Darko

    2016-03-01

    Full Text Available This study addresses the problem of magnetic field emission produced by the laptop computers. Although, the magnetic field is spread over the entire frequency spectrum, the most dangerous part of it to the laptop users is the frequency range from 50 to 500 Hz, commonly called the extremely low frequency magnetic field. In this frequency region the magnetic field is characterized by high peak values. To examine the influence of laptop’s magnetic field emission in the office, a specific experiment is proposed. It includes the measurement of the magnetic field at six laptop’s positions, which are in close contact to its user. The results obtained from ten different laptop computers show the extremely high emission at some positions, which are dependent on the power dissipation or bad ergonomics. Eventually, the experiment extracts these dangerous positions of magnetic field emission and suggests possible solutions.

  6. Generation of artificial time-histories, rich in all frequencies, from given response spectra

    International Nuclear Information System (INIS)

    Levy, S.; Wilkinson, J.P.D.

    1975-01-01

    In order to apply the time-history method of seismic analysis, it is often desirable to generate a suitable artificial time-history from a given response spectrum. The method described allows the generation of such a time-history that is also rich in all frequencies in the spectrum. This richness is achieved by choosing a large number of closely-spaced frequency points such that the adjacent frequencies have their half-power points overlap. The adjacent frequencies satisfy the condition that the frequency interval Δf near a given frequency f is such that (Δf)/f<2c/csub(c) where c is the damping of the system and csub(c) is the critical damping. In developing an artificial time-history, it is desirable to specify the envelope and duration of the record, very often in such a manner as to reproduce the envelope property of a specific earthquake record, and such an option is available in the method described. Examples are given of the development of typical artificial time-histories from earthquake design response spectra and from floor response spectra

  7. A neural signature of phonological access: distinguishing the effects of word frequency from familiarity and length in overt picture naming.

    Science.gov (United States)

    Graves, William W; Grabowski, Thomas J; Mehta, Sonya; Gordon, Jean K

    2007-04-01

    Cognitive models of word production correlate the word frequency effect (i.e., the fact that words which appear with less frequency take longer to produce) with an increased processing cost to activate the whole-word (lexical) phonological representation. We performed functional magnetic resonance imaging (fMRI) while subjects produced overt naming responses to photographs of animals and manipulable objects that had high name agreement but were of varying frequency, with the purpose of identifying neural structures participating specifically in activating whole-word phonological representations, as opposed to activating lexical semantic representations or articulatory-motor routines. Blood oxygen level-dependent responses were analyzed using a parametric approach based on the frequency with which each word produced appears in the language. Parallel analyses were performed for concept familiarity and word length, which provided indices of semantic and articulatory loads. These analyses permitted us to identify regions related to word frequency alone, and therefore, likely to be related specifically to activation of phonological word forms. We hypothesized that the increased processing cost of producing lower-frequency words would correlate with activation of the left posterior inferotemporal (IT) cortex, the left posterior superior temporal gyrus (pSTG), and the left inferior frontal gyrus (IFG). Scan-time response latencies demonstrated the expected word frequency effect. Analysis of the fMRI data revealed that activity in the pSTG was modulated by frequency but not word length or concept familiarity. In contrast, parts of IT and IFG demonstrated conjoint frequency and familiarity effects, and parts of both primary motor regions demonstrated conjoint effects of frequency and word length. The results are consistent with a model of word production in which lexical-semantic and lexical-phonological information are accessed by overlapping neural systems within

  8. AUTOMATIC FREQUENCY CONTROL SYSTEM

    Science.gov (United States)

    Hansen, C.F.; Salisbury, J.D.

    1961-01-10

    A control is described for automatically matching the frequency of a resonant cavity to that of a driving oscillator. The driving oscillator is disconnected from the cavity and a secondary oscillator is actuated in which the cavity is the frequency determining element. A low frequency is mixed with the output of the driving oscillator and the resultant lower and upper sidebands are separately derived. The frequencies of the sidebands are compared with the secondary oscillator frequency. deriving a servo control signal to adjust a tuning element in the cavity and matching the cavity frequency to that of the driving oscillator. The driving oscillator may then be connected to the cavity.

  9. Modulation of Somatosensory Alpha Rhythm by Transcranial Alternating Current Stimulation at Mu-Frequency

    Directory of Open Access Journals (Sweden)

    Christopher Gundlach

    2017-08-01

    Full Text Available Introduction: Transcranial alternating current stimulation (tACS is emerging as an interventional tool to modulate different functions of the brain, potentially by interacting with intrinsic ongoing neuronal oscillations. Functionally different intrinsic alpha oscillations are found throughout the cortex. Yet it remains unclear whether tACS is capable of specifically modulating the somatosensory mu-rhythm in amplitude.Objectives: We used tACS to modulate mu-alpha oscillations in amplitude. When compared to sham stimulation we expected a modulation of mu-alpha oscillations but not visual alpha oscillations by tACS.Methods: Individual mu-alpha frequencies were determined in 25 participants. Subsequently, blocks of tACS with individual mu-alpha frequency and sham stimulation were applied over primary somatosensory cortex (SI. Electroencephalogram (EEG was recorded before and after either stimulation or sham. Modulations of mu-alpha and, for control, visual alpha amplitudes were then compared between tACS and sham.Results: Somatosensory mu-alpha oscillations decreased in amplitude after tACS was applied at participants’ individual mu-alpha frequency. No changes in amplitude were observed for sham stimulation. Furthermore, visual alpha oscillations were not affected by tACS or sham, respectively.Conclusion: Our results demonstrate the capability of tACS to specifically modulate the targeted somatosensory mu-rhythm when the tACS frequency is tuned to the individual endogenous rhythm and applied over somatosensory areas. Our results are in contrast to previously reported amplitude increases of visual alpha oscillations induced by tACS applied over visual cortex. Our results may point to a specific interaction between our stimulation protocol and the functional architecture of the somatosensory system.

  10. An Analysis of the High Frequency Vibrations in Early Thematic Mapper Scenes

    Science.gov (United States)

    Kogut, J.; Larduinat, E.

    1985-01-01

    The motion of the mirrors in the thematic mapper (TM) and multispectral scanner (MSS) instruments, and the motion of other devices, such as the TDRSS antenna drive, and solar array drives onboard LANDSAT-4 cause vibrations to propagate through the spacecraft. These vibrations as well as nonlinearities in the scanning motion of the TM mirror can cause the TM detectors to point away from their nominal positions. Two computer programs, JITTER and SCDFT, were developed as part of the LANDSAT-D Assessment System (LAS), Products and Procedures Analysis (PAPA) program to evaluate the potential effect of high frequency vibrations on the final TM image. The maximum overlap and underlap which were observed for early TM scenes are well within specifications for the ground processing system. The cross scan and scan high frequency vibrations are also within the specifications cited for the flight system.

  11. Frequency domain modeling and dynamic characteristics evaluation of existing wind turbine systems

    Science.gov (United States)

    Chiang, Chih-Hung; Yu, Chih-Peng

    2016-04-01

    It is quite well accepted that frequency domain procedures are suitable for the design and dynamic analysis of wind turbine structures, especially for floating offshore wind turbines, since random wind loads and wave induced motions are most likely simulated in the frequency domain. This paper presents specific applications of an effective frequency domain scheme to the linear analysis of wind turbine structures in which a 1-D spectral element was developed based on the axially-loaded member. The solution schemes are summarized for the spectral analyses of the tower, the blades, and the combined system with selected frequency-dependent coupling effect from foundation-structure interactions. Numerical examples demonstrate that the modal frequencies obtained using spectral-element models are in good agreement with those found in the literature. A 5-element mono-pile model results in less than 0.3% deviation from an existing 160-element model. It is preliminarily concluded that the proposed scheme is relatively efficient in performing quick verification for test data obtained from the on-site vibration measurement using the microwave interferometer.

  12. Characteristics of spectro-temporal modulation frequency selectivity in humans.

    Science.gov (United States)

    Oetjen, Arne; Verhey, Jesko L

    2017-03-01

    There is increasing evidence that the auditory system shows frequency selectivity for spectro-temporal modulations. A recent study of the authors has shown spectro-temporal modulation masking patterns that were in agreement with the hypothesis of spectro-temporal modulation filters in the human auditory system [Oetjen and Verhey (2015). J. Acoust. Soc. Am. 137(2), 714-723]. In the present study, that experimental data and additional data were used to model this spectro-temporal frequency selectivity. The additional data were collected to investigate to what extent the spectro-temporal modulation-frequency selectivity results from a combination of a purely temporal amplitude-modulation filter and a purely spectral amplitude-modulation filter. In contrast to the previous study, thresholds were measured for masker and target modulations with opposite directions, i.e., an upward pointing target modulation and a downward pointing masker modulation. The comparison of this data set with previous corresponding data with the same direction from target and masker modulations indicate that a specific spectro-temporal modulation filter is required to simulate all aspects of spectro-temporal modulation frequency selectivity. A model using a modified Gabor filter with a purely temporal and a purely spectral filter predicts the spectro-temporal modulation masking data.

  13. Development of a Saudi Food Frequency Questionnaire and testing its reliability and validity

    OpenAIRE

    Gosadi, Ibrahim M.; Alatar, Abdullah A.; Otayf, Mojahed M.; AlJahani, Dhaherah M.; Ghabbani, Hisham M.; AlRajban, Waleed A.; Alrsheed, Abdullah M.; Al-Nasser, Khalid A.

    2017-01-01

    Objectives: To create a food frequency questionnaire specifically designed to capture the dietary habits of Saudis and test its validity and reliability. Methods: This investigation is a longitudinal, test-retest study conducted in King Saud University, Riyadh, Kingdom of Saudi Arabia between December 2015 and March 2016. A list of 140 food items was included in the questionnaire where a closed-ended and open-ended approach was used. Regarding past year food frequency consumption and 24 hours...

  14. Frequency of Psychological Disorders amongst Children in Urban Areas of Tehran

    Directory of Open Access Journals (Sweden)

    Narges Joshaghani

    2010-06-01

    Full Text Available Objective: To evaluate the frequency of different psychiatric disorders among 7 to 12 years old children in urban areas of Tehran. "nMethod: A sample of 799 children (6 to 11 years old were selected from 250 clusters of the entire 22 municipality areas of Tehran using a multistage sampling method from 250 clusters from the entire 22 municipality areas of Tehran. . After responding to a Persian version of the Strengths and Difficulties Questionnaire (SDQ parent-report form, the Persian version of Kiddie Schedule for Affective Disorders and Schizophrenia - Present and Lifetime (K-SADS-PL was administered to 241 children and their families. The frequency of child psychological disorders was determined using the results of K-SADS-PL. "n Results:The overall frequency of any psychological disorders in the sample of children was 17.9 percent. Among the interviewed children childrenwho were interviewed, the most prevalent diagnoses were Attention-Deficit/ Hyperactivity Disorder (ADHD (8.6 percent8.6%, Oppositional Defiant Disorder (ODD (7.3 percent7.3%, and separation anxiety disorder (SAD (5.9 percent5.9%. There were not any statistically significant differences between sexes in the frequency of psychological disorders except enuresis that was more frequent in the boys and anorexia nervosa that was observed more frequently in the girls . "nConclusion:Higher frequency of ADHD and ODD and SAD among the studied children warrantswarrants more specific evaluation of frequency and possible causes of these high frequency rates. The frequency of psychological disorders in the studied children was comparable to the that of other studies.

  15. A critical examination of the numerology of antigen-binding cells: evidence for multiple receptor specificities on single cells.

    Science.gov (United States)

    Miller, A

    1977-01-01

    The data available from other laboratories as well as our own on the frequency of cells recognizing major histocompatibility antigens or conventional protein and hapten antigens is critically evaluated. The frequency of specific binding for a large number of antigens is sufficiently high to support the idea that at least part of the antigen-binding cell population must have multiple specificities. Our results suggest that these multiple specific cells result from single cells synthesizing and displaying as many as 50-100 species of receptor, each at a frequency of 10(4) per cell. A model involving gene expansion of constant-region genes is suggested and some auxilliary evidence consistent with such C-gene expansion is presented.

  16. Calibration-free absolute frequency response measurement of directly modulated lasers based on additional modulation.

    Science.gov (United States)

    Zhang, Shangjian; Zou, Xinhai; Wang, Heng; Zhang, Yali; Lu, Rongguo; Liu, Yong

    2015-10-15

    A calibration-free electrical method is proposed for measuring the absolute frequency response of directly modulated semiconductor lasers based on additional modulation. The method achieves the electrical domain measurement of the modulation index of directly modulated lasers without the need for correcting the responsivity fluctuation in the photodetection. Moreover, it doubles measuring frequency range by setting a specific frequency relationship between the direct and additional modulation. Both the absolute and relative frequency response of semiconductor lasers are experimentally measured from the electrical spectrum of the twice-modulated optical signal, and the measured results are compared to those obtained with conventional methods to check the consistency. The proposed method provides calibration-free and accurate measurement for high-speed semiconductor lasers with high-resolution electrical spectrum analysis.

  17. High-frequency homogenization of zero frequency stop band photonic and phononic crystals

    CERN Document Server

    Antonakakis, Tryfon; Guenneau, Sebastien

    2013-01-01

    We present an accurate methodology for representing the physics of waves, for periodic structures, through effective properties for a replacement bulk medium: This is valid even for media with zero frequency stop-bands and where high frequency phenomena dominate. Since the work of Lord Rayleigh in 1892, low frequency (or quasi-static) behaviour has been neatly encapsulated in effective anisotropic media. However such classical homogenization theories break down in the high-frequency or stop band regime. Higher frequency phenomena are of significant importance in photonics (transverse magnetic waves propagating in infinite conducting parallel fibers), phononics (anti-plane shear waves propagating in isotropic elastic materials with inclusions), and platonics (flexural waves propagating in thin-elastic plates with holes). Fortunately, the recently proposed high-frequency homogenization (HFH) theory is only constrained by the knowledge of standing waves in order to asymptotically reconstruct dispersion curves an...

  18. High Specificity of Quantitative Methylation-Specific PCR Analysis for MGMT Promoter Hypermethylation Detection in Gliomas

    Directory of Open Access Journals (Sweden)

    Paola Parrella

    2009-01-01

    Full Text Available Normal brain tissue from 28 individuals and 50 glioma samples were analyzed by real-time Quantitative Methylation-Specific PCR (QMSP. Data from this analysis were compared with results obtained on the same samples by MSP. QMSP analysis demonstrated a statistically significant difference in both methylation level (P=.000009 Mann Whitney Test and frequencies (P=.0000007, Z-test in tumour samples as compared with normal brain tissues. Although QMSP and MSP showed similar sensitivity, the specificity of QMSP analysis was significantly higher (93%; CI95%: 84%–100% as compared with MSP (64%; 95%CI: 46%–82%. Our results suggest that QMSP analysis may represent a powerful tool to identify glioma patients that will benefit from alkylating agents chemotherapy.

  19. Higher frequency network activity flow predicts lower frequency node activity in intrinsic low-frequency BOLD fluctuations.

    Science.gov (United States)

    Bajaj, Sahil; Adhikari, Bhim Mani; Dhamala, Mukesh

    2013-01-01

    The brain remains electrically and metabolically active during resting conditions. The low-frequency oscillations (LFO) of the blood oxygen level-dependent (BOLD) signal of functional magnetic resonance imaging (fMRI) coherent across distributed brain regions are known to exhibit features of this activity. However, these intrinsic oscillations may undergo dynamic changes in time scales of seconds to minutes during resting conditions. Here, using wavelet-transform based time-frequency analysis techniques, we investigated the dynamic nature of default-mode networks from intrinsic BOLD signals recorded from participants maintaining visual fixation during resting conditions. We focused on the default-mode network consisting of the posterior cingulate cortex (PCC), the medial prefrontal cortex (mPFC), left middle temporal cortex (LMTC) and left angular gyrus (LAG). The analysis of the spectral power and causal flow patterns revealed that the intrinsic LFO undergo significant dynamic changes over time. Dividing the frequency interval 0 to 0.25 Hz of LFO into four intervals slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), slow-3 (0.073-0.198 Hz) and slow-2 (0.198-0.25 Hz), we further observed significant positive linear relationships of slow-4 in-out flow of network activity with slow-5 node activity, and slow-3 in-out flow of network activity with slow-4 node activity. The network activity associated with respiratory related frequency (slow-2) was found to have no relationship with the node activity in any of the frequency intervals. We found that the net causal flow towards a node in slow-3 band was correlated with the number of fibers, obtained from diffusion tensor imaging (DTI) data, from the other nodes connecting to that node. These findings imply that so-called resting state is not 'entirely' at rest, the higher frequency network activity flow can predict the lower frequency node activity, and the network activity flow can reflect underlying structural

  20. Dual-Phase Lock-In Amplifier Based on FPGA for Low-Frequencies Experiments

    Directory of Open Access Journals (Sweden)

    Gonzalo Macias-Bobadilla

    2016-03-01

    Full Text Available Photothermal techniques allow the detection of characteristics of material without invading it. Researchers have developed hardware for some specific Phase and Amplitude detection (Lock-In Function applications, eliminating space and unnecessary electronic functions, among others. This work shows the development of a Digital Lock-In Amplifier based on a Field Programmable Gate Array (FPGA for low-frequency applications. This system allows selecting and generating the appropriated frequency depending on the kind of experiment or material studied. The results show good frequency stability in the order of 1.0 × 10−9 Hz, which is considered good linearity and repeatability response for the most common Laboratory Amplitude and Phase Shift detection devices, with a low error and standard deviation.

  1. Finding Specification Pages from the Web

    Science.gov (United States)

    Yoshinaga, Naoki; Torisawa, Kentaro

    This paper presents a method of finding a specification page on the Web for a given object (e.g., ``Ch. d'Yquem'') and its class label (e.g., ``wine''). A specification page for an object is a Web page which gives concise attribute-value information about the object (e.g., ``county''-``Sauternes'') in well formatted structures. A simple unsupervised method using layout and symbolic decoration cues was applied to a large number of the Web pages to acquire candidate attributes for each class (e.g., ``county'' for a class ``wine''). We then filter out irrelevant words from the putative attributes through an author-aware scoring function that we called site frequency. We used the acquired attributes to select a representative specification page for a given object from the Web pages retrieved by a normal search engine. Experimental results revealed that our system greatly outperformed the normal search engine in terms of this specification retrieval.

  2. 18 centimeter VLBI observations of the quasar NRAO 140 during and after a low-frequency outburst

    International Nuclear Information System (INIS)

    Marscher, A.P.; Broderick, J.J.; Padrielli, L.; Bartel, N.; Romney, J.D.; Virginia Polytechnic Institute and State Univ., Blacksburg; CNR, Istituto di Radioastronomia, Bologna, Italy; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA; Natitonal Radio Astronomy Observatory, Charlottesville, VA)

    1987-01-01

    VLBI and spectra observations have been used to identify the specific site of a low-frequency outburst in the quasar NRAO 140. The properties of the low-frequency variability in the quasar are compared with the predictions of several models. The refractive scintillation model alone does not account for the source's properties. 32 references

  3. The vestibular implant: Frequency-dependency of the electrically evoked Vestibulo-Ocular Reflex in humans

    Directory of Open Access Journals (Sweden)

    Raymond eVan De Berg

    2015-01-01

    Full Text Available The Vestibulo-Ocular Reflex (VOR shows frequency-dependent behavior. This study investigated whether the characteristics of the electrically evoked VOR (eVOR elicited by a vestibular implant, showed the same frequency-dependency.Twelve vestibular electrodes implanted in 7 patients with bilateral vestibular hypofunction were tested. Stimuli consisted of amplitude-modulated electrical stimulation with a sinusoidal profile at frequencies of 0.5Hz, 1Hz, and 2Hz. The main characteristics of the eVOR were evaluated and compared to the natural VOR characteristics measured in a group of age-matched healthy volunteers who were subjected to horizontal whole body rotations with equivalent sinusoidal velocity profiles at the same frequencies.A strong and significant effect of frequency was observed in the total peak eye velocity of the eVOR. This effect was similar to that observed in the natural VOR. Other characteristics of the (eVOR (angle, habituation-index, and asymmetry showed no significant frequency-dependent effect. In conclusion, this study demonstrates that, at least at the specific (limited frequency range tested, responses elicited by a vestibular implant closely mimic the frequency-dependency of the normal vestibular system.

  4. Influence of test reliability on the screening performance of frequency-doubling perimetry

    NARCIS (Netherlands)

    Heeg, GP; Jansonius, NM

    PURPOSE: To investigate the influence of test reliability on the screening performance of frequency,doubling perimetry (FDT). DESIGN: Cross-sectional study. METHODS: FDT sensitivity and specificity were calculated three times using three different strategies for handling unreliable (that is, > 0

  5. Diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference

    Energy Technology Data Exchange (ETDEWEB)

    Ren Cheng; Zhang Shulian, E-mail: ren-c06@mails.tsinghua.edu.c [State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China)

    2009-08-07

    The diode-pumped dual-frequency microchip Nd : YAG laser with tunable frequency difference is presented. The gain medium used is a microchip 2 mm in thickness for miniaturized and integrated design. Two quarter-wave plates are placed into the laser cavity and the intra-cavity birefringence produces two orthogonally linearly polarized modes. The rotation of one of the two quarter-wave plates introduces a controlled and variable cavity birefringence which causes a variable frequency difference between the two orthogonally polarized modes. The frequency difference can be tuned through the whole cavity free spectral range. The obtained frequency difference ranges from 14 MHz to 1.5 GHz. The variation of the beat frequency over a period of 10 min is less than 10 kHz. The lock-in between modes is not found. Experimental results are presented, which match well with the theoretical analysis based on Jones matrices.

  6. Sensitivity of human auditory cortex to rapid frequency modulation revealed by multivariate representational similarity analysis.

    Science.gov (United States)

    Joanisse, Marc F; DeSouza, Diedre D

    2014-01-01

    Functional Magnetic Resonance Imaging (fMRI) was used to investigate the extent, magnitude, and pattern of brain activity in response to rapid frequency-modulated sounds. We examined this by manipulating the direction (rise vs. fall) and the rate (fast vs. slow) of the apparent pitch of iterated rippled noise (IRN) bursts. Acoustic parameters were selected to capture features used in phoneme contrasts, however the stimuli themselves were not perceived as speech per se. Participants were scanned as they passively listened to sounds in an event-related paradigm. Univariate analyses revealed a greater level and extent of activation in bilateral auditory cortex in response to frequency-modulated sweeps compared to steady-state sounds. This effect was stronger in the left hemisphere. However, no regions showed selectivity for either rate or direction of frequency modulation. In contrast, multivoxel pattern analysis (MVPA) revealed feature-specific encoding for direction of modulation in auditory cortex bilaterally. Moreover, this effect was strongest when analyses were restricted to anatomical regions lying outside Heschl's gyrus. We found no support for feature-specific encoding of frequency modulation rate. Differential findings of modulation rate and direction of modulation are discussed with respect to their relevance to phonetic discrimination.

  7. Laser frequency stabilization by combining modulation transfer and frequency modulation spectroscopy.

    Science.gov (United States)

    Zi, Fei; Wu, Xuejian; Zhong, Weicheng; Parker, Richard H; Yu, Chenghui; Budker, Simon; Lu, Xuanhui; Müller, Holger

    2017-04-01

    We present a hybrid laser frequency stabilization method combining modulation transfer spectroscopy (MTS) and frequency modulation spectroscopy (FMS) for the cesium D2 transition. In a typical pump-probe setup, the error signal is a combination of the DC-coupled MTS error signal and the AC-coupled FMS error signal. This combines the long-term stability of the former with the high signal-to-noise ratio of the latter. In addition, we enhance the long-term frequency stability with laser intensity stabilization. By measuring the frequency difference between two independent hybrid spectroscopies, we investigate the short-and long-term stability. We find a long-term stability of 7.8 kHz characterized by a standard deviation of the beating frequency drift over the course of 10 h and a short-term stability of 1.9 kHz characterized by an Allan deviation of that at 2 s of integration time.

  8. Wavelet analysis of frequency chaos game signal: a time-frequency signature of the C. elegans DNA.

    Science.gov (United States)

    Messaoudi, Imen; Oueslati, Afef Elloumi; Lachiri, Zied

    2014-12-01

    Challenging tasks are encountered in the field of bioinformatics. The choice of the genomic sequence's mapping technique is one the most fastidious tasks. It shows that a judicious choice would serve in examining periodic patterns distribution that concord with the underlying structure of genomes. Despite that, searching for a coding technique that can highlight all the information contained in the DNA has not yet attracted the attention it deserves. In this paper, we propose a new mapping technique based on the chaos game theory that we call the frequency chaos game signal (FCGS). The particularity of the FCGS coding resides in exploiting the statistical properties of the genomic sequence itself. This may reflect important structural and organizational features of DNA. To prove the usefulness of the FCGS approach in the detection of different local periodic patterns, we use the wavelet analysis because it provides access to information that can be obscured by other time-frequency methods such as the Fourier analysis. Thus, we apply the continuous wavelet transform (CWT) with the complex Morlet wavelet as a mother wavelet function. Scalograms that relate to the organism Caenorhabditis elegans (C. elegans) exhibit a multitude of periodic organization of specific DNA sequences.

  9. High-frequency self-aligned graphene transistors with transferred gate stacks

    Science.gov (United States)

    Cheng, Rui; Bai, Jingwei; Liao, Lei; Zhou, Hailong; Chen, Yu; Liu, Lixin; Lin, Yung-Chen; Jiang, Shan; Huang, Yu; Duan, Xiangfeng

    2012-01-01

    Graphene has attracted enormous attention for radio-frequency transistor applications because of its exceptional high carrier mobility, high carrier saturation velocity, and large critical current density. Herein we report a new approach for the scalable fabrication of high-performance graphene transistors with transferred gate stacks. Specifically, arrays of gate stacks are first patterned on a sacrificial substrate, and then transferred onto arbitrary substrates with graphene on top. A self-aligned process, enabled by the unique structure of the transferred gate stacks, is then used to position precisely the source and drain electrodes with minimized access resistance or parasitic capacitance. This process has therefore enabled scalable fabrication of self-aligned graphene transistors with unprecedented performance including a record-high cutoff frequency up to 427 GHz. Our study defines a unique pathway to large-scale fabrication of high-performance graphene transistors, and holds significant potential for future application of graphene-based devices in ultra–high-frequency circuits. PMID:22753503

  10. Aurally-adequate time-frequency analysis for scattered sound in auditoria

    Science.gov (United States)

    Norris, Molly K.; Xiang, Ning; Kleiner, Mendel

    2005-04-01

    The goal of this work was to apply an aurally-adequate time-frequency analysis technique to the analysis of sound scattering effects in auditoria. Time-frequency representations were developed as a motivated effort that takes into account binaural hearing, with a specific implementation of interaural cross-correlation process. A model of the human auditory system was implemented in the MATLAB platform based on two previous models [A. Härmä and K. Palomäki, HUTear, Espoo, Finland; and M. A. Akeroyd, A. Binaural Cross-correlogram Toolbox for MATLAB (2001), University of Sussex, Brighton]. These stages include proper frequency selectivity, the conversion of the mechanical motion of the basilar membrane to neural impulses, and binaural hearing effects. The model was then used in the analysis of room impulse responses with varying scattering characteristics. This paper discusses the analysis results using simulated and measured room impulse responses. [Work supported by the Frank H. and Eva B. Buck Foundation.

  11. Integrated circuit for processing a low-frequency signal from a seismic detector

    Energy Technology Data Exchange (ETDEWEB)

    Malashevich, N. I.; Roslyakov, A. S.; Polomoshnov, S. A., E-mail: S.Polomoshnov@tsen.ru; Fedorov, R. A. [Research and Production Complex ' Technological Center' of the Moscow Institute of Electronic Technology (Russian Federation)

    2011-12-15

    Specific features for the detection and processing of a low-frequency signal from a seismic detector are considered in terms of an integrated circuit based on a large matrix crystal of the 5507 series. This integrated circuit is designed for the detection of human movements. The specific features of the information signal, obtained at the output of the seismic detector, and the main characteristics of the integrated circuit and its structure are reported.

  12. Sum frequency generation image reconstruction: Aliphatic membrane under spherical cap geometry

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Victor [Bereozovaya 2A, Konstantinovo, Moscow Region 140207 (Russian Federation)

    2014-10-07

    The article explores an opportunity to approach structural properties of phospholipid membranes using Sum Frequency Generation microscopy. To establish the principles of sum frequency generation image reconstruction in such systems, at first approach, we may adopt an idealistic spherical cap uniform assembly of hydrocarbon molecules. Quantum mechanical studies for decanoic acid (used here as a representative molecular system) provide necessary information on transition dipole moments and Raman tensors of the normal modes specific to methyl terminal – a typical moiety in aliphatic (and phospholipid) membranes. Relative degree of localization and frequencies of the normal modes of methyl terminals make nonlinearities of this moiety to be promising in structural analysis using Sum Frequency Generation imaging. Accordingly, the article describes derivations of relevant macroscopic nonlinearities and suggests a mapping procedure to translate amplitudes of the nonlinearities onto microscopy image plane according to geometry of spherical assembly, local molecular orientation, and optical geometry. Reconstructed images indicate a possibility to extract local curvature of bilayer envelopes of spherical character. This may have practical implications for structural extractions in membrane systems of practical relevance.

  13. Effect of echolocation behavior-related constant frequency-frequency modulation sound on the frequency tuning of inferior collicular neurons in Hipposideros armiger.

    Science.gov (United States)

    Tang, Jia; Fu, Zi-Ying; Wei, Chen-Xue; Chen, Qi-Cai

    2015-08-01

    In constant frequency-frequency modulation (CF-FM) bats, the CF-FM echolocation signals include both CF and FM components, yet the role of such complex acoustic signals in frequency resolution by bats remains unknown. Using CF and CF-FM echolocation signals as acoustic stimuli, the responses of inferior collicular (IC) neurons of Hipposideros armiger were obtained by extracellular recordings. We tested the effect of preceding CF or CF-FM sounds on the shape of the frequency tuning curves (FTCs) of IC neurons. Results showed that both CF-FM and CF sounds reduced the number of FTCs with tailed lower-frequency-side of IC neurons. However, more IC neurons experienced such conversion after adding CF-FM sound compared with CF sound. We also found that the Q 20 value of the FTC of IC neurons experienced the largest increase with the addition of CF-FM sound. Moreover, only CF-FM sound could cause an increase in the slope of the neurons' FTCs, and such increase occurred mainly in the lower-frequency edge. These results suggested that CF-FM sound could increase the accuracy of frequency analysis of echo and cut-off low-frequency elements from the habitat of bats more than CF sound.

  14. Evaluation of a Validated Food Frequency Questionnaire for Self-Defined Vegans in the United States

    Science.gov (United States)

    Dyett, Patricia; Rajaram, Sujatha; Haddad, Ella H.; Sabate, Joan

    2014-01-01

    This study aimed to develop and validate a de novo food frequency questionnaire for self-defined vegans in the United States. Diet histories from pilot samples of vegans and a modified ‘Block Method’ using seven selected nutrients of concern in vegan diet patterns, were employed to generate the questionnaire food list. Food frequency responses of 100 vegans from 19 different U.S. states were obtained via completed mailed questionnaires and compared to multiple telephone-conducted diet recall interviews. Computerized diet analyses were performed. Correlation coefficients, t-tests, rank, cross-tabulations, and probability tests were used to validate and compare intake estimates and dietary reference intake (DRI) assessment trends between the two methods. A 369-item vegan-specific questionnaire was developed with 252 listed food frequency items. Calorie-adjusted correlation coefficients ranged from r = 0.374 to 0.600 (p vegans). This vegan-specific questionnaire can be a useful assessment tool for health screening initiatives in U.S. vegan communities. PMID:25006856

  15. Evaluation of a validated food frequency questionnaire for self-defined vegans in the United States.

    Science.gov (United States)

    Dyett, Patricia; Rajaram, Sujatha; Haddad, Ella H; Sabate, Joan

    2014-07-08

    This study aimed to develop and validate a de novo food frequency questionnaire for self-defined vegans in the United States. Diet histories from pilot samples of vegans and a modified 'Block Method' using seven selected nutrients of concern in vegan diet patterns, were employed to generate the questionnaire food list. Food frequency responses of 100 vegans from 19 different U.S. states were obtained via completed mailed questionnaires and compared to multiple telephone-conducted diet recall interviews. Computerized diet analyses were performed. Correlation coefficients, t-tests, rank, cross-tabulations, and probability tests were used to validate and compare intake estimates and dietary reference intake (DRI) assessment trends between the two methods. A 369-item vegan-specific questionnaire was developed with 252 listed food frequency items. Calorie-adjusted correlation coefficients ranged from r = 0.374 to 0.600 (p vegans). This vegan-specific questionnaire can be a useful assessment tool for health screening initiatives in U.S. vegan communities.

  16. Associations between family dinner frequency and specific food behaviors among grade six, seven, and eight students from Ontario and Nova Scotia.

    Science.gov (United States)

    Woodruff, Sarah J; Hanning, Rhona M

    2009-05-01

    Family dinner frequency has recently been associated in the literature with improved dietary profiles and healthy body weight in children and adolescents. However, it is not known whether family dinners are associated with other commonly reported food behaviors (fast food and soft drink consumption, breakfast skipping, and dieting) and attitudes (body weight concerns and self-efficacy for healthy eating) among Canadian students in grades 6, 7, and 8. A total of 3223 participants from Northern Ontario (Porcupine Region), Southern Ontario (Peel Region, Region of Waterloo, Toronto District), and Nova Scotia completed the Food Behavior Questionnaire during the 2005-2006 academic school year. Ordinal logistic regression analyses were used to determine the associations between family dinner frequency and food behaviors and attitudes. Higher family dinner frequency was significantly associated with less soft drink consumption, consuming breakfast on the day of the survey, the absence of a high body weight concern, having higher self-efficacy for healthy eating when at home with family, and during social times with friends. Researchers and clinicians should be aware of these associations when planning family based healthy eating strategies.

  17. High-precision coseismic displacement estimation with a single-frequency GPS receiver

    Science.gov (United States)

    Guo, Bofeng; Zhang, Xiaohong; Ren, Xiaodong; Li, Xingxing

    2015-07-01

    To improve the performance of Global Positioning System (GPS) in the earthquake/tsunami early warning and rapid response applications, minimizing the blind zone and increasing the stability and accuracy of both the rapid source and rupture inversion, the density of existing GPS networks must be increased in the areas at risk. For economic reasons, low-cost single-frequency receivers would be preferable to make the sparse dual-frequency GPS networks denser. When using single-frequency GPS receivers, the main problem that must be solved is the ionospheric delay, which is a critical factor when determining accurate coseismic displacements. In this study, we introduce a modified Satellite-specific Epoch-differenced Ionospheric Delay (MSEID) model to compensate for the effect of ionospheric error on single-frequency GPS receivers. In the MSEID model, the time-differenced ionospheric delays observed from a regional dual-frequency GPS network to a common satellite are fitted to a plane rather than part of a sphere, and the parameters of this plane are determined by using the coordinates of the stations. When the parameters are known, time-differenced ionospheric delays for a single-frequency GPS receiver could be derived from the observations of those dual-frequency receivers. Using these ionospheric delay corrections, coseismic displacements of a single-frequency GPS receiver can be accurately calculated based on time-differenced carrier-phase measurements in real time. The performance of the proposed approach is validated using 5 Hz GPS data collected during the 2012 Nicoya Peninsula Earthquake (Mw 7.6, 2012 September 5) in Costa Rica. This shows that the proposed approach improves the accuracy of the displacement of a single-frequency GPS station, and coseismic displacements with an accuracy of a few centimetres are achieved over a 10-min interval.

  18. Input signal shaping based on harmonic frequency response function for suppressing nonlinear optical frequency in frequency-scanning interferometry

    Science.gov (United States)

    Zhu, Yu; Liu, Zhigang; Deng, Wen; Deng, Zhongwen

    2018-05-01

    Frequency-scanning interferometry (FSI) using an external cavity diode laser (ECDL) is essential for many applications of the absolute distance measurement. However, owing to the hysteresis and creep of the piezoelectric actuator inherent in the ECDL, the optical frequency scanning exhibits a nonlinearity that seriously affects the phase extraction accuracy of the interference signal and results in the reduction of the measurement accuracy. To suppress the optical frequency nonlinearity, a harmonic frequency synthesis method for shaping the desired input signal instead of the original triangular wave is presented. The effectiveness of the presented shaping method is demonstrated through the comparison of the experimental results. Compared with an incremental Renishaw interferometer, the standard deviation of the displacement measurement of the FSI system is less than 2.4 μm when driven by the shaped signal.

  19. Validation of a short food frequency questionnaire specific for iodine in U.K. females of childbearing age.

    Science.gov (United States)

    Combet, E; Lean, M E J

    2014-12-01

    Widespread subclinical iodine insufficiency has recently been reported in Europe, based on urinary iodine using World Health Organization/Food and Agriculture Organization criteria, in particular among young women. Although urinary iodine concentration (UIC) is a useful measurement of the iodine status in a population, it does not provide an insight into the habitual iodine intake of this population. This is compounded by the fact that very few iodine-specific food frequency questionnaires (FFQ) have been validated so far. The present study aimed to develop and validate a new, simple, rapid survey tool to assess dietary iodine exposure in females of childbearing age. Iodine was measured in a duplicate 24-h urine collection. Iodine intake was measured with duplicate 4-day semi-quantitative food diaries and the FFQ. Correlation, cross-classification and Bland-Altman analyses were used to estimate agreement, bias and the reliability of the method. The triangular (triad) method was used to calculate validity coefficients. Forty-three women, aged 19-49 years, took part in the validation of the 17-items FFQ. Median (interquartile range) UIC was 74 (47-92) μg L(-1) , which is indicative of mild iodine insufficiency. The FFQ showed good agreement with food diaries with respect to classifying iodine intake (82% of subjects were classified in the same or adjacent quartile). The FFQ was moderately correlated with the food diaries (rs  = 0.45, P = 0.002) and urinary excretion in μg L(-1) (rs  = 0.34, P = 0.025) but not in μg day(-1) (P = 0.316). The validity coefficients were 0.69, 0.66 and 0.52 for the food diaries, FFQ and urinary iodine excretion, respectively. The FFQ provides a rapid and reliable estimate of dietary iodine exposure to identify those population subgroups at risk of iodine deficiency. © 2014 The British Dietetic Association Ltd.

  20. Effect of low-frequency power on dual-frequency capacitively coupled plasmas

    International Nuclear Information System (INIS)

    Yuan, Q H; Xin, Y; Huang, X J; Sun, K; Ning, Z Y; Yin, G Q

    2008-01-01

    In low-pressure dual-frequency capacitively coupled plasmas driven with 60/13.56 MHz, the effect of low-frequency power on the plasma characteristics was investigated using a compensated Langmuir electrostatic probe. At lower pressures (about 10 mTorr), it was possible to control the plasma density and the ion bombardment energy independently. As the pressure increased, this independent control could not be achieved. As the low-frequency power increased for the fixed high-frequency power, the electron energy probability function (EEPF) changed from Druyvesteyn-like to Maxwellian-like at pressures of 50 mTorr and higher, along with a drop in electron temperature. The plasma parameters were calculated and compared with simulation results.

  1. Radio Frequency Microelectromechanical Systems [Book Chapter Manuscript

    Energy Technology Data Exchange (ETDEWEB)

    Nordquist, Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Olsson, Roy H. [Defense Advanced Research Projects Agency (DARPA), Albuquerque, NM (United States)

    2014-12-15

    Radio frequency microelectromechanical system (RF MEMS) devices are microscale devices that achieve superior performance relative to other technologies by taking advantage of the accuracy, precision, materials, and miniaturization available through microfabrication. To do this, these devices use their mechanical and electrical properties to perform a specific RF electrical function such as switching, transmission, or filtering. RF MEMS has been a popular area of research since the early 1990s, and within the last several years, the technology has matured sufficiently for commercialization and use in commercial market systems.

  2. ENVIRONMENTAL SPECIFICATION REQUIREMENTS

    International Nuclear Information System (INIS)

    TIFFT, S.R.

    2003-01-01

    Through regulations, permitting or binding negotiations, Regulators establish requirements, limits, permit conditions and Notice of Construction (NOC) conditions with which the Office of River Protection (ORP) and the Tank Farm Contractor (TFC) must comply. Operating Specifications are technical limits which are set on a process to prevent injury to personnel, or damage to the facility or environment. The main purpose of this document is to provide specification limits and recovery actions for the TFC Environmental Surveillance Program at the Hanford Site. Specification limits are given for monitoring frequencies and permissible variation of readings from an established baseline or previous reading. The requirements in this document are driven by environmental considerations and data analysis issues, rather than facility design or personnel safety issues. This document is applicable to all single-shell tank (SST) and double-shell tank (DST) waste tanks, and the associated catch tanks and receiver tanks, and transfer systems. This Tank Farm Environmental Specifications Document (ESD) implements environmental-regulatory limits on the configuration and operation of the Hanford Tank Farms facility that have been established by Regulators. This ESD contains specific field operational limits and recovery actions for compliance with airborne effluent regulations and agreements, liquid effluents regulations and agreements, and environmental tank system requirements. The scope of this ESD is limited to conditions that have direct impact on Operations Projects or that Operations/Projects have direct impact upon. This document does not supercede or replace any DOE Orders, regulatory permits, notices of construction, or Regulatory agency agreements binding on the ORP or the TFC. Refer to the appropriate regulation, permit, or NOC for an inclusive listing of requirements

  3. Survey on the frequency of somatic mutations in A-bomb survivors

    International Nuclear Information System (INIS)

    Akiyama, Mitoshi

    1992-01-01

    Several methods have recently been established for quantitatively detecting somatic cell mutations on a specific locus using human blood cells. These methods have enabled the biological estimation of A-bomb radiation doses in surveys on somatic cell mutations. This paper outlines HPRT, GPA, and TCR assays used to measure somatic cell mutations, focusing on the outcome in A-bomb survivors. HPRT assay is based on colony formation with interleukin-2. The frequency of HPRT mutant cells was significantly increased with advancing age in A-bomb survivors and was positively correlated with the frequency of chromosomal aberrations in lymphocytes. There was also a significantly positive correlation between HPRT mutant cell frequencies and DS86 estimated doses, although the slope was slow. In GPA assay, flow cytometric measurements of fluorescence-labeled erythrocytes are used to detect somatic cell mutations. There was a positive correlation between GPA mutant cell frequencies and age in A-bomb survivors. The GPA mutant cell frequencies showed much more positive correlation with lymphocyte chromosomal aberration frequencies than the HPRT mutant cell frequencies. When anti-CD3 antibody and anti-CD4 antibody are labeled with different fluorescences and are analyzed by using flow cytometry, TCR mutant cells having CD3 - 4 + can be detected. When the frequency of TCR mutant cells was examined in 342 A-bomb survivors, it did not correlate with radiation doses. This implies that TCR assay may be unadequate for biological estimation of A-bomb radiation doses throughout a lifetime of A-bomb survivors, because TCR mutant cells seems to be unable to live for a long time due to national selection. (N.K.)

  4. Specific heat of praseodymium and neodymium

    International Nuclear Information System (INIS)

    Narayana Murthy, J.V.S.S.; Ramji Rao, R.

    1983-01-01

    The elements of the dynamical matrix of an ideal deep lattice, with nearest neighbour central interactions, have been obtained in a homogeneously strained state. The dispersion relations along the [0001] direction, on this model, have been presented for Pr and Nd. The frequency distribution function g(ω) is obtained and the lattice specific heat is calculated for Pr and Nd and the temperature variation of the equivalent Debye temperature is presented. (author)

  5. Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus.

    Directory of Open Access Journals (Sweden)

    Roland Frey

    Full Text Available Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0 and a high (g0 fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0. Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female captive dholes (Cuon alpinus and for 2 (1 male, 1 female wild red fox (Vulpes vulpes. In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.

  6. Generation of artificial time-histories, rich in all frequencies from given response spectra

    International Nuclear Information System (INIS)

    Levy, S.; Wilkinson, J.P.D.

    1975-01-01

    In order to apply the time-history method of seismic analysis, it is often desirable to generate a suitable artificial time-history from a given response spectrum. The method described in this paper allows the generation of such a time-history that is also rich in all frequencies in the spectrum. This richness is achieved by choosing a large number of closely-spaced frequency points such that the adjacent frequencies have their half-power points overlap. The adjacent frequencies satisfy the condition that the frequency interval Δf near a given frequency f is such that (Δf)/f<2c/csub(c) where c is the damping of the system and csub(c) is the critical damping. In developing an artificial time-history, it is desirable to specify the envelope and duration of the record, very often in such a manner as to reproduce the envelope property of a specific earthquake record, and such an option is available in the method described. Examples are given of the development of typical articifial time-histories from earthquake design response spectra and from floor response spectra. (Auth.)

  7. Grass-specific CD4+ T-cells exhibit varying degrees of cross-reactivity, implications for allergen-specific immunotherapy

    Science.gov (United States)

    Archila, LD; DeLong, JH; Wambre, E; James, EA; Robinson, DM; Kwok, WW

    2014-01-01

    Background Conceptually, allergic responses may involve cross-reactivity by antibodies or T-cells. While IgE cross-reactivity amongst grass pollen allergens has been observed, cross-reactivity at the allergen-specific T-cell level has been less documented. Identification of the patterns of cross-reactivity may improve our understanding, allowing optimization of better immunotherapy strategies. Objectives We use Phleum pratense as model for the studying of cross-reactivity at the allergen-specific CD4+ T cell level amongst DR04:01 restricted Pooideae grass pollen T-cell epitopes. Methods After In vitro culture of blood mononucleated cells from Grass-pollen allergic subjects with specific Pooideae antigenic epitopes, dual tetramer staining with APC-labeled DR04:01/Phleum pratense tetramers and PE-labeled DR04:01/Pooideae grass homolog tetramers was assessed to identify cross-reactivity amongst allergen-specific DR04:01-restricted T-cells in 6 subjects. Direct ex vivo staining enabled the comparison of frequency and phenotype of different Pooideae grass pollen reactive T-cells. Intracellular cytokine staining (ICS) assays were also used to examine phenotypes of these T-cells. Results T-cells with various degree of cross reactive profiles could be detected. Poa p 1 97-116, Lol p 1 221-240, Lol p 5a 199-218, and Poa p 5a 199-218 were identified as minimally-cross-reactive T-cell epitopes that do not show cross reactivity to Phl p 1 and Phl p 5a epitopes. Ex vivo tetramer staining assays demonstrated T-cells that recognized these minimally-cross reactive T-cell epitopes are present in Grass-pollen allergic subjects. Conclusions Our results suggest that not all Pooideae grass epitopes with sequence homology are cross-reactive. Non-cross reactive T-cells with comparable frequency, phenotype and functionality to Phl p-specific T-cells, suggest that a multiple allergen system should be considered for immunotherapy instead of a mono allergen system. PMID:24708411

  8. Grass-specific CD4(+) T-cells exhibit varying degrees of cross-reactivity, implications for allergen-specific immunotherapy.

    Science.gov (United States)

    Archila, L D; DeLong, J H; Wambre, E; James, E A; Robinson, D M; Kwok, W W

    2014-07-01

    Conceptually, allergic responses may involve cross-reactivity by antibodies or T-cells. While IgE cross-reactivity among grass-pollen allergens has been observed, cross-reactivity at the allergen-specific T-cell level has been less documented. Identification of the patterns of cross-reactivity may improve our understanding, allowing optimization of better immunotherapy strategies. We use Phleum pratense as model for the studying of cross-reactivity at the allergen-specific CD4(+) T cell level among DR04:01 restricted Pooideae grass-pollen T-cell epitopes. After in vitro culture of blood mono-nucleated cells from grass-pollen-allergic subjects with specific Pooideae antigenic epitopes, dual tetramer staining with APC-labelled DR04:01/Phleum pratense tetramers and PE-labelled DR04:01/Pooideae grass homolog tetramers was assessed to identify cross-reactivity among allergen-specific DR04:01-restricted T-cells in six subjects. Direct ex vivo staining enabled the comparison of frequency and phenotype of different Pooideae grass-pollen reactive T-cells. Intracellular cytokine staining (ICS) assays were also used to examine phenotypes of these T-cells. T-cells with various degrees of cross-reactive profiles could be detected. Poa p 1 97-116 , Lol p 1 221-240 , Lol p 5a 199-218 , and Poa p 5a 199-218 were identified as minimally cross-reactive T-cell epitopes that do not show cross-reactivity to Phl p 1 and Phl p 5a epitopes. Ex vivo tetramer staining assays demonstrated T-cells that recognized these minimally cross-reactive T-cell epitopes are present in Grass-pollen-allergic subjects. Our results suggest that not all Pooideae grass epitopes with sequence homology are cross-reactive. Non-cross-reactive T-cells with comparable frequency, phenotype and functionality to Phl p-specific T-cells suggest that a multiple allergen system should be considered for immunotherapy instead of a mono-allergen system. © 2014 John Wiley & Sons Ltd.

  9. Multiple Frequencies in the Basal Ganglia in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Clare M. Davidson

    2015-01-01

    Full Text Available In recent years, the authors have developed what appears to be a very successful phenomenological model for analyzing the role of deep brain stimulation (DBS in alleviating the symptoms of Parkinson's disease. In this paper, we extend the scope of the model by using it to predict the generation of new frequencies from networks tuned to a specific frequency, or indeed not self-oscillatory at all. We have discussed two principal cases: firstly where the constituent systems are coupled in an excitatory-excitatory fashion, which we designate by ``+/+''; and secondly where the constituent systems are coupled in an excitatory-inhibitory fashion, which we designate ``+/-''. The model predicts that from a basic system tuned to tremor frequency we can generate an unlimited range of frequencies. We illustrate in particular, starting from systems which are initially non-oscillatory, that when the coupling coefficient exceeds a certain value, the system begins to oscillate at an amplitude which increases with the coupling strength. Another very interesting feature, which has been shown by colleagues of ours to arise through the coupling of complicated networks based on the physiology of the basal ganglia, can be illustrated by the root locus method which shows that increasing and decreasing frequencies of oscillation, existing simultaneously, have the property that their geometric mean remains substantially constant as the coupling strength is varied. We feel that with the present approach, we have provided another tool for understanding the existence and interaction of pathological oscillations which underlie, not only Parkinson's disease, but other conditions such as Tourette's syndrome, depression and epilepsy.

  10. Digital sorting of complex tissues for cell type-specific gene expression profiles.

    Science.gov (United States)

    Zhong, Yi; Wan, Ying-Wooi; Pang, Kaifang; Chow, Lionel M L; Liu, Zhandong

    2013-03-07

    Cellular heterogeneity is present in almost all gene expression profiles. However, transcriptome analysis of tissue specimens often ignores the cellular heterogeneity present in these samples. Standard deconvolution algorithms require prior knowledge of the cell type frequencies within a tissue or their in vitro expression profiles. Furthermore, these algorithms tend to report biased estimations. Here, we describe a Digital Sorting Algorithm (DSA) for extracting cell-type specific gene expression profiles from mixed tissue samples that is unbiased and does not require prior knowledge of cell type frequencies. The results suggest that DSA is a specific and sensitivity algorithm in gene expression profile deconvolution and will be useful in studying individual cell types of complex tissues.

  11. Genome of the Netherlands population-specific imputations identify an ABCA6 variant associated with cholesterol levels

    Science.gov (United States)

    van Leeuwen, Elisabeth M.; Karssen, Lennart C.; Deelen, Joris; Isaacs, Aaron; Medina-Gomez, Carolina; Mbarek, Hamdi; Kanterakis, Alexandros; Trompet, Stella; Postmus, Iris; Verweij, Niek; van Enckevort, David J.; Huffman, Jennifer E.; White, Charles C.; Feitosa, Mary F.; Bartz, Traci M.; Manichaikul, Ani; Joshi, Peter K.; Peloso, Gina M.; Deelen, Patrick; van Dijk, Freerk; Willemsen, Gonneke; de Geus, Eco J.; Milaneschi, Yuri; Penninx, Brenda W.J.H.; Francioli, Laurent C.; Menelaou, Androniki; Pulit, Sara L.; Rivadeneira, Fernando; Hofman, Albert; Oostra, Ben A.; Franco, Oscar H.; Leach, Irene Mateo; Beekman, Marian; de Craen, Anton J.M.; Uh, Hae-Won; Trochet, Holly; Hocking, Lynne J.; Porteous, David J.; Sattar, Naveed; Packard, Chris J.; Buckley, Brendan M.; Brody, Jennifer A.; Bis, Joshua C.; Rotter, Jerome I.; Mychaleckyj, Josyf C.; Campbell, Harry; Duan, Qing; Lange, Leslie A.; Wilson, James F.; Hayward, Caroline; Polasek, Ozren; Vitart, Veronique; Rudan, Igor; Wright, Alan F.; Rich, Stephen S.; Psaty, Bruce M.; Borecki, Ingrid B.; Kearney, Patricia M.; Stott, David J.; Adrienne Cupples, L.; Neerincx, Pieter B.T.; Elbers, Clara C.; Francesco Palamara, Pier; Pe'er, Itsik; Abdellaoui, Abdel; Kloosterman, Wigard P.; van Oven, Mannis; Vermaat, Martijn; Li, Mingkun; Laros, Jeroen F.J.; Stoneking, Mark; de Knijff, Peter; Kayser, Manfred; Veldink, Jan H.; van den Berg, Leonard H.; Byelas, Heorhiy; den Dunnen, Johan T.; Dijkstra, Martijn; Amin, Najaf; Joeri van der Velde, K.; van Setten, Jessica; Kattenberg, Mathijs; van Schaik, Barbera D.C.; Bot, Jan; Nijman, Isaäc J.; Mei, Hailiang; Koval, Vyacheslav; Ye, Kai; Lameijer, Eric-Wubbo; Moed, Matthijs H.; Hehir-Kwa, Jayne Y.; Handsaker, Robert E.; Sunyaev, Shamil R.; Sohail, Mashaal; Hormozdiari, Fereydoun; Marschall, Tobias; Schönhuth, Alexander; Guryev, Victor; Suchiman, H. Eka D.; Wolffenbuttel, Bruce H.; Platteel, Mathieu; Pitts, Steven J.; Potluri, Shobha; Cox, David R.; Li, Qibin; Li, Yingrui; Du, Yuanping; Chen, Ruoyan; Cao, Hongzhi; Li, Ning; Cao, Sujie; Wang, Jun; Bovenberg, Jasper A.; Jukema, J. Wouter; van der Harst, Pim; Sijbrands, Eric J.; Hottenga, Jouke-Jan; Uitterlinden, Andre G.; Swertz, Morris A.; van Ommen, Gert-Jan B.; de Bakker, Paul I.W.; Eline Slagboom, P.; Boomsma, Dorret I.; Wijmenga, Cisca; van Duijn, Cornelia M.

    2015-01-01

    Variants associated with blood lipid levels may be population-specific. To identify low-frequency variants associated with this phenotype, population-specific reference panels may be used. Here we impute nine large Dutch biobanks (~35,000 samples) with the population-specific reference panel created by the Genome of the Netherlands Project and perform association testing with blood lipid levels. We report the discovery of five novel associations at four loci (P value <6.61 × 10−4), including a rare missense variant in ABCA6 (rs77542162, p.Cys1359Arg, frequency 0.034), which is predicted to be deleterious. The frequency of this ABCA6 variant is 3.65-fold increased in the Dutch and its effect (βLDL-C=0.135, βTC=0.140) is estimated to be very similar to those observed for single variants in well-known lipid genes, such as LDLR. PMID:25751400

  12. A frequency-based linguistic approach to protein decoding and design: Simple concepts, diverse applications, and the SCS Package

    Science.gov (United States)

    Motomura, Kenta; Nakamura, Morikazu; Otaki, Joji M.

    2013-01-01

    Protein structure and function information is coded in amino acid sequences. However, the relationship between primary sequences and three-dimensional structures and functions remains enigmatic. Our approach to this fundamental biochemistry problem is based on the frequencies of short constituent sequences (SCSs) or words. A protein amino acid sequence is considered analogous to an English sentence, where SCSs are equivalent to words. Availability scores, which are defined as real SCS frequencies in the non-redundant amino acid database relative to their probabilistically expected frequencies, demonstrate the biological usage bias of SCSs. As a result, this frequency-based linguistic approach is expected to have diverse applications, such as secondary structure specifications by structure-specific SCSs and immunological adjuvants with rare or non-existent SCSs. Linguistic similarities (e.g., wide ranges of scale-free distributions) and dissimilarities (e.g., behaviors of low-rank samples) between proteins and the natural English language have been revealed in the rank-frequency relationships of SCSs or words. We have developed a web server, the SCS Package, which contains five applications for analyzing protein sequences based on the linguistic concept. These tools have the potential to assist researchers in deciphering structurally and functionally important protein sites, species-specific sequences, and functional relationships between SCSs. The SCS Package also provides researchers with a tool to construct amino acid sequences de novo based on the idiomatic usage of SCSs. PMID:24688703

  13. A FREQUENCY-BASED LINGUISTIC APPROACH TO PROTEIN DECODING AND DESIGN: SIMPLE CONCEPTS, DIVERSE APPLICATIONS, AND THE SCS PACKAGE

    Directory of Open Access Journals (Sweden)

    Kenta Motomura

    2013-02-01

    Full Text Available Protein structure and function information is coded in amino acid sequences. However, the relationship between primary sequences and three-dimensional structures and functions remains enigmatic. Our approach to this fundamental biochemistry problem is based on the frequencies of short constituent sequences (SCSs or words. A protein amino acid sequence is considered analogous to an English sentence, where SCSs are equivalent to words. Availability scores, which are defined as real SCS frequencies in the non-redundant amino acid database relative to their probabilistically expected frequencies, demonstrate the biological usage bias of SCSs. As a result, this frequency-based linguistic approach is expected to have diverse applications, such as secondary structure specifications by structure-specific SCSs and immunological adjuvants with rare or non-existent SCSs. Linguistic similarities (e.g., wide ranges of scale-free distributions and dissimilarities (e.g., behaviors of low-rank samples between proteins and the natural English language have been revealed in the rank-frequency relationships of SCSs or words. We have developed a web server, the SCS Package, which contains five applications for analyzing protein sequences based on the linguistic concept. These tools have the potential to assist researchers in deciphering structurally and functionally important protein sites, species-specific sequences, and functional relationships between SCSs. The SCS Package also provides researchers with a tool to construct amino acid sequences de novo based on the idiomatic usage of SCSs.

  14. Deterministically swapping frequency-bin entanglement from photon-photon to atom-photon hybrid systems

    Science.gov (United States)

    Ou, Bao-Quan; Liu, Chang; Sun, Yuan; Chen, Ping-Xing

    2018-02-01

    Inspired by the recent developments of the research on the atom-photon quantum interface and energy-time entanglement between single-photon pulses, we are motivated to study the deterministic protocol for the frequency-bin entanglement of the atom-photon hybrid system, which is analogous to the frequency-bin entanglement between single-photon pulses. We show that such entanglement arises naturally in considering the interaction between a frequency-bin entangled single-photon pulse pair and a single atom coupled to an optical cavity, via straightforward atom-photon phase gate operations. Its anticipated properties and preliminary examples of its potential application in quantum networking are also demonstrated. Moreover, we construct a specific quantum entanglement witness tool to detect such extended frequency-bin entanglement from a reasonably general set of separable states, and prove its capability theoretically. We focus on the energy-time considerations throughout the analysis.

  15. Specific immunotherapy modifies allergen-specific CD4+ T cell responses in an epitope-dependent manner

    Science.gov (United States)

    Wambre, Erik; DeLong, Jonathan H.; James, Eddie A.; Torres-Chinn, Nadia; Pfützner, Wolfgang; Möbs, Christian; Durham, Stephen R.; Till, Stephen J.; Robinson, David; Kwok, William W.

    2014-01-01

    Background Understanding the mechanisms by which the immune system induces and controls allergic inflammation at the T cell epitope level is critical for the design of new allergy vaccine strategies. Objective To characterize allergen-specific T cell responses linked with allergy or peripheral tolerance and to determine how CD4+ T cell responses to individual allergen-derived epitopes change over allergen-specific immunotherapy (ASIT). Methods Timothy grass pollen (TGP) allergy was used as a model for studying grass pollen allergies. The breadth, magnitude, epitope hierarchy and phenotype of the DR04:01-restricted TGP-specific T cell responses in ten grass pollen allergic, five non-atopic and six allergy vaccine-treated individuals was determined using an ex vivo pMHCII-tetramer approach. Results CD4+ T cells in allergic individuals are directed to a broad range of TGP epitopes characterized by defined immunodominance hierarchy patterns and with distinct functional profiles that depend on the epitope recognized. Epitopes that are restricted specifically to either TH2 or TH1/TR1 responses were identified. ASIT was associated with preferential deletion of allergen-specific TH2 cells and without significant change in frequency of TH1/TR1 cells. Conclusions Preferential allergen-specific TH2-cells deletion after repeated high doses antigen stimulation can be another independent mechanism to restore tolerance to allergen during immunotherapy. PMID:24373351

  16. Design and development of ITER high-frequency magnetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y., E-mail: Yunxing.Ma@iter.org [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Fircroft Engineering, Lingley House, 120 Birchwood Point, Birchwood Boulevard, Warrington, WA3 7QH (United Kingdom); Vayakis, G. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Begrambekov, L.B. [National Research Nuclear University (MEPhI), 115409, Moscow, Kashirskoe shosse 31 (Russian Federation); Cooper, J.-J. [Culham Centre for Fusion Energy (CCFE), Abingdon, Oxfordshire OX14 3DB (United Kingdom); Duran, I. [IPP Prague, Za Slovankou 1782/3, 182 00 Prague 8 (Czech Republic); Hirsch, M.; Laqua, H.P. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Moreau, Ph. [CEA Cadarache, 13108 Saint Paul lez Durance Cedex (France); Oosterbeek, J.W. [Eindhoven University of Technology (TU/e), PO Box 513, 5600 MB Eindhoven (Netherlands); Spuig, P. [CEA Cadarache, 13108 Saint Paul lez Durance Cedex (France); Stange, T. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Walsh, M. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2016-11-15

    Highlights: • ITER high-frequency magnetic sensor system has been designed. • Prototypes have been successfully manufactured. • Manufactured prototypes have been tested in various labs. • Test results experimentally validated the design. - Abstract: High-frequency (HF) inductive magnetic sensors are the primary ITER diagnostic set for Toroidal Alfvén Eigenmodes (TAE) detection, while they also supplement low-frequency MHD and plasma equilibrium measurements. These sensors will be installed on the inner surface of ITER vacuum vessel, operated in a harsh environment with considerable neutron/nuclear radiation and high thermal load. Essential components of the HF sensor system, including inductive coil, electron cyclotron heating (ECH) shield, electrical cabling and termination load, have been designed to meet ITER measurement requirements. System performance (e.g. frequency response, thermal conduction) has been assessed. A prototyping campaign was initiated to demonstrate the manufacturability of the designed components. Prototypes have been produced according to the specifications. A series of lab tests have been performed to examine assembly issues and validate electrical and thermo-mechanical aspects of the design. In-situ microwave radiation test has been conducted in the MISTRAL test facility at IPP-Greifswald to experimentally examine the microwave shielding efficiency and structural integrity of the ECH shield. Low-power microwave attenuation measurement and scanning electron microscopic inspection were conducted to probe and examine the quality of the metal coating on the ECH shield.

  17. Frequency-Selective Attention in Auditory Scenes Recruits Frequency Representations Throughout Human Superior Temporal Cortex.

    Science.gov (United States)

    Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

    2017-05-01

    A sound of interest may be tracked amid other salient sounds by focusing attention on its characteristic features including its frequency. Functional magnetic resonance imaging findings have indicated that frequency representations in human primary auditory cortex (AC) contribute to this feat. However, attentional modulations were examined at relatively low spatial and spectral resolutions, and frequency-selective contributions outside the primary AC could not be established. To address these issues, we compared blood oxygenation level-dependent (BOLD) responses in the superior temporal cortex of human listeners while they identified single frequencies versus listened selectively for various frequencies within a multifrequency scene. Using best-frequency mapping, we observed that the detailed spatial layout of attention-induced BOLD response enhancements in primary AC follows the tonotopy of stimulus-driven frequency representations-analogous to the "spotlight" of attention enhancing visuospatial representations in retinotopic visual cortex. Moreover, using an algorithm trained to discriminate stimulus-driven frequency representations, we could successfully decode the focus of frequency-selective attention from listeners' BOLD response patterns in nonprimary AC. Our results indicate that the human brain facilitates selective listening to a frequency of interest in a scene by reinforcing the fine-grained activity pattern throughout the entire superior temporal cortex that would be evoked if that frequency was present alone. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  18. Narrow-band 1, 2, 3, 4, 8, 16 and 24 cycles/360o angular frequency filters

    Directory of Open Access Journals (Sweden)

    Simas M.L.B.

    2002-01-01

    Full Text Available We measured human frequency response functions for seven angular frequency filters whose test frequencies were centered at 1, 2, 3, 4, 8, 16 or 24 cycles/360º using a supra-threshold summation method. The seven functions of 17 experimental conditions each were measured nine times for five observers. For the arbitrarily selected filter phases, the maximum summation effect occurred at test frequency for filters at 1, 2, 3, 4 and 8 cycles/360º. For both 16 and 24 cycles/360º test frequencies, maximum summation occurred at the lower harmonics. These results allow us to conclude that there are narrow-band angular frequency filters operating somehow in the human visual system either through summation or inhibition of specific frequency ranges. Furthermore, as a general result, it appears that addition of higher angular frequencies to lower ones disturbs low angular frequency perception (i.e., 1, 2, 3 and 4 cycles/360º, whereas addition of lower harmonics to higher ones seems to improve detection of high angular frequency harmonics (i.e., 8, 16 and 24 cycles/360º. Finally, we discuss the possible involvement of coupled radial and angular frequency filters in face perception using an example where narrow-band low angular frequency filters could have a major role.

  19. Electrocorticography and the early maturation of high-frequency suppression within the default mode network.

    Science.gov (United States)

    Weaver, Kurt E; Poliakov, Andrew; Novotny, Edward J; Olson, Jared D; Grabowski, Thomas J; Ojemann, Jeffrey G

    2018-02-01

    OBJECTIVE The acquisition and refinement of cognitive and behavioral skills during development is associated with the maturation of various brain oscillatory activities. Most developmental investigations have identified distinct patterns of low-frequency electrophysiological activity that are characteristic of various behavioral milestones. In this investigation, the authors focused on the cross-sectional developmental properties of high-frequency spectral power from the brain's default mode network (DMN) during goal-directed behavior. METHODS The authors contrasted regionally specific, time-evolving high gamma power (HGP) in the lateral DMN cortex between 3 young children (age range 3-6 years) and 3 adults by use of electrocorticography (ECoG) recordings over the left perisylvian cortex during a picture-naming task. RESULTS Across all participants, a nearly identical and consistent response suppression of HGP, which is a functional signature of the DMN, was observed during task performance recordings acquired from ECoG electrodes placed over the lateral DMN cortex. This finding provides evidence of relatively early maturation of the DMN. Furthermore, only HGP relative to evoked alpha and beta band power showed this level of consistency across all participants. CONCLUSIONS Regionally specific, task-evoked suppression of the high-frequency components of the cortical power spectrum is established early in brain development, and this response may reflect the early maturation of specific cognitive and/or computational mechanisms.

  20. Identification of antigen-specific human monoclonal antibodies using high-throughput sequencing of the antibody repertoire.

    Science.gov (United States)

    Liu, Ju; Li, Ruihua; Liu, Kun; Li, Liangliang; Zai, Xiaodong; Chi, Xiangyang; Fu, Ling; Xu, Junjie; Chen, Wei

    2016-04-22

    High-throughput sequencing of the antibody repertoire provides a large number of antibody variable region sequences that can be used to generate human monoclonal antibodies. However, current screening methods for identifying antigen-specific antibodies are inefficient. In the present study, we developed an antibody clone screening strategy based on clone dynamics and relative frequency, and used it to identify antigen-specific human monoclonal antibodies. Enzyme-linked immunosorbent assay showed that at least 52% of putative positive immunoglobulin heavy chains composed antigen-specific antibodies. Combining information on dynamics and relative frequency improved identification of positive clones and elimination of negative clones. and increase the credibility of putative positive clones. Therefore the screening strategy could simplify the subsequent experimental screening and may facilitate the generation of antigen-specific antibodies. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Low-Frequency Pulsed Current Versus Kilohertz-Frequency Alternating Current: A Scoping Literature Review.

    Science.gov (United States)

    Vaz, Marco Aurélio; Frasson, Viviane Bortoluzzi

    2018-04-01

    To compare the effectiveness of low-frequency pulsed current versus kilohertz-frequency alternating current in terms of evoked force, discomfort level, current intensity, and muscle fatigability; to discuss the physiological mechanisms of each neuromuscular electrical stimulation type; and to determine if kilohertz-frequency alternating current is better than low-frequency pulsed current for clinical treatment. Articles were obtained from PubMed, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, MEDLINE, and SPORTSDiscus databases using the terms Russian current or kilohertz current or alternating current or pulsed current or Aussie current and torque or discomfort or fatigue or current intensity, and through citation tracking up to July 2017. Two independent reviewers selected studies comparing the use of the 2 neuromuscular electrical stimulation currents. Studies describing maximal current intensity tolerated and the main effects of the 2 different current types on discomfort, muscle force, and fatigability were independently reviewed. Data were systematized according to (1) methodology; (2) electrical current characteristics; and (3) outcomes on discomfort level, evoked force, current intensity, and muscle fatigability. The search revealed 15 articles comparing the 2 current types. Kilohertz-frequency alternated current generated equal or less force, similar discomfort, similar current intensity for maximal tolerated neuromuscular electrical stimulation, and more fatigue compared with low-frequency pulsed current. Similar submaximal levels of evoked force revealed higher discomfort and current intensity for kilohertz-frequency alternated current compared with low-frequency pulsed current. Available evidence does not support the idea that kilohertz-frequency alternated current is better than low-frequency pulsed current for strength training and rehabilitation. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier

  2. Effects of Foot Strike and Step Frequency on Achilles Tendon Stress During Running.

    Science.gov (United States)

    Lyght, Michael; Nockerts, Matthew; Kernozek, Thomas W; Ragan, Robert

    2016-08-01

    Achilles tendon (AT) injuries are common in runners. The AT withstands high magnitudes of stress during running which may contribute to injury. Our purpose was to examine the effects of foot strike pattern and step frequency on AT stress and strain during running utilizing muscle forces based on a musculoskeletal model and subject-specific ultrasound-derived AT cross-sectional area. Nineteen female runners performed running trials under 6 conditions, including rearfoot strike and forefoot strike patterns at their preferred cadence, +5%, and -5% preferred cadence. Rearfoot strike patterns had less peak AT stress (P forefoot strike pattern. A reduction in peak AT stress and strain were exhibited with a +5% preferred step frequency relative to the preferred condition using a rearfoot (P forefoot (P=.005) strike pattern. Strain rate was not different (P > .05) between step frequencies within each foot strike condition. Our results suggest that a rearfoot pattern may reduce AT stress, strain, and strain rate. Increases in step frequency of 5% above preferred frequency, regardless of foot strike pattern, may also lower peak AT stress and strain.

  3. Autoantibody frequency in celiac disease

    Directory of Open Access Journals (Sweden)

    Erkan Caglar

    2009-01-01

    Full Text Available AIM: In our study, we investigated the levels of glutamic acid decarboxylase antibody (anti-GAD, islet cell antibody (ICA, thyroperoxidase antibody (anti-TPO, thyroglobulin antibody (anti-TG, antinuclear antibodies (FANA, antibodies to double-stranded DNA (anti-ds DNA, antibody to Sjögren syndrome A antigen (anti-SSA, antibody to Sjögren syndrome B antigen (anti-SSB, Smith antibody (anti-Sm, smooth muscle antibodies (ASMA, and antimitochondrial antibody liver-kidney microsome (AMA-LKM in patients with celiac disease as compared to healthy controls and autoimmune hypothyroid patients. MATERIALS AND METHODS: A total of 31 patients with celiac disease, 34 patients with autoimmune hypothyroidism and 29 healthy subjects were included in this study. Anti-SSA, anti-SSB, anti-Sm, anti-ds DNA, anti-GAD, anti-TPO and anti-TG were studied by Enzyme-Linked Immunosorbent Assay (ELISA, and AMA-LKM, ASMA, ANA and ICA were studied by immunofluorescence. Clinical data and the results of free thyroxine-thyroid stimulating hormone (FT4-TSH were collected from the patients' files by retrospective analysis. SPSS ver 13.0 was used for data analysis, and the χ2 method was used for comparisons within groups. RESULTS: The frequency of anti-SSA, anti-SSB, anti-GAD, anti-Sm, anti-ds DNA, AMA-LKM, ASMA, ANA and ICA were not significantly different between the groups. Levels of anti-TPO and anti-TG antibodies were found to be significantly higher (<0.001 in autoimmune hypothyroid patients when compared with other groups. CONCLUSION: In previous studies, an increased frequency of autoimmune diseases of other systems has been reported in patients with celiac disease. We found that the frequency of autoimmune antibodies specific for other autoimmune diseases was not higher in celiac disease.

  4. Breakfast frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Damsgaard, Mogens Trab

    2016-01-01

    OBJECTIVE: To investigate (i) associations between adolescents' frequency of breakfast and family functioning (close relations to parents, quality of family communication and family support) and (ii) if any observed associations between breakfast frequency and family functioning vary...... (n 3054) from a random sample of forty-one schools. RESULTS: Nearly one-quarter of the adolescents had low breakfast frequency. Low breakfast frequency was associated with low family functioning measured by three dimensions. The OR (95 % CI) of low breakfast frequency was 1·81 (1·40, 2......·33) for adolescents who reported no close relations to parents, 2·28 (1·61, 3·22) for adolescents who reported low level of quality of family communication and 2·09 (1·39, 3·15) for adolescents who reported low level of family support. Joint effect analyses suggested that the odds of low breakfast frequency among...

  5. The effect of feeding frequency on growth performance and body ...

    African Journals Online (AJOL)

    This study was done to investigate the effects of different feeding frequencies on the growth, feed efficiency and specific growth rate (%) of juvenile of rainbow trout (Oncorhynchus mykiss, weight 16.44±0.22 g) rearing in cold sea water conditions (5.8 to 9.3°C; 17 to 18 ppt). Fish were fed on a commercial feed to the apparent ...

  6. Neurons in the inferior colliculus of the rat show stimulus-specific adaptation for frequency, but not for intensity

    Science.gov (United States)

    Duque, Daniel; Wang, Xin; Nieto-Diego, Javier; Krumbholz, Katrin; Malmierca, Manuel S.

    2016-01-01

    Electrophysiological and psychophysical responses to a low-intensity probe sound tend to be suppressed by a preceding high-intensity adaptor sound. Nevertheless, rare low-intensity deviant sounds presented among frequent high-intensity standard sounds in an intensity oddball paradigm can elicit an electroencephalographic mismatch negativity (MMN) response. This has been taken to suggest that the MMN is a correlate of true change or “deviance” detection. A key question is where in the ascending auditory pathway true deviance sensitivity first emerges. Here, we addressed this question by measuring low-intensity deviant responses from single units in the inferior colliculus (IC) of anesthetized rats. If the IC exhibits true deviance sensitivity to intensity, IC neurons should show enhanced responses to low-intensity deviant sounds presented among high-intensity standards. Contrary to this prediction, deviant responses were only enhanced when the standards and deviants differed in frequency. The results could be explained with a model assuming that IC neurons integrate over multiple frequency-tuned channels and that adaptation occurs within each channel independently. We used an adaptation paradigm with multiple repeated adaptors to measure the tuning widths of these adaption channels in relation to the neurons’ overall tuning widths. PMID:27066835

  7. Low-frequency quantitative ultrasound imaging of cell death in vivo

    International Nuclear Information System (INIS)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J.; Papanicolau, Naum; Tadayyon, Hadi; Lee, Justin; Zubovits, Judit; Sadeghian, Alireza; Karshafian, Raffi; Al-Mahrouki, Azza; Giles, Anoja; Kolios, Michael C.

    2013-01-01

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r 2 = 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency, in

  8. Low-frequency quantitative ultrasound imaging of cell death in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J. [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Papanicolau, Naum; Tadayyon, Hadi [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Lee, Justin [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Zubovits, Judit [Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Sadeghian, Alireza [Department of Computer Science, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Karshafian, Raffi [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Al-Mahrouki, Azza; Giles, Anoja [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Kolios, Michael C. [Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5, Canada and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)

    2013-08-15

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r{sup 2}= 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency

  9. HF heating of a plasma column at frequencies below the electron cyclotron frequency

    International Nuclear Information System (INIS)

    Datlov, J.; Kopecky, V.; Musil, J.; Zacek, F.; Novik, K.

    1978-02-01

    The dispersion of waves, excited by the helical structure in a plasma column and the heating of a tail of the electron distribution function is studied at frequencies below the electron plasma frequency and the electron cyclotron frequency. (author)

  10. Frequency-Locked Single-Frequency Fiber Laser at 2 Micron, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Frequency-locked single-frequency 2 micron fiber laser is proposed to be used for airborne/spaceborne coherent lidar measurements, i.e., Active Sensing of CO2...

  11. Frequency shift and hysteresis suppression in contact-mode AFM using contact stiffness modulation

    Directory of Open Access Journals (Sweden)

    Belhaq M.

    2012-07-01

    Full Text Available In this paper the frequency response shift and hysteresis suppression of contact-mode atomic force microscopy is investigated using parametric modulation of the contact stiffness. Based on the Hertzian contact theory, a lumped single degree of freedom oscillator is considered for modeling the cantilever dynamics contact-mode atomic force microscopy. We use the technique of direct partition of motion and the method of multiple scales to obtain, respectively, the slow dynamic and the corresponding slow flow of the system. As results, this study shows that the amplitude of the contact stiffness modulation has a significant effect on the frequency response. Specifically, increasing the amplitude of the stiffness modulation suppresses hysteresis, decreases the peak amplitude and produces shifts towards higher and lower frequencies.

  12. Object discrimination using optimized multi-frequency auditory cross-modal haptic feedback.

    Science.gov (United States)

    Gibson, Alison; Artemiadis, Panagiotis

    2014-01-01

    As the field of brain-machine interfaces and neuro-prosthetics continues to grow, there is a high need for sensor and actuation mechanisms that can provide haptic feedback to the user. Current technologies employ expensive, invasive and often inefficient force feedback methods, resulting in an unrealistic solution for individuals who rely on these devices. This paper responds through the development, integration and analysis of a novel feedback architecture where haptic information during the neural control of a prosthetic hand is perceived through multi-frequency auditory signals. Through representing force magnitude with volume and force location with frequency, the feedback architecture can translate the haptic experiences of a robotic end effector into the alternative sensory modality of sound. Previous research with the proposed cross-modal feedback method confirmed its learnability, so the current work aimed to investigate which frequency map (i.e. frequency-specific locations on the hand) is optimal in helping users distinguish between hand-held objects and tasks associated with them. After short use with the cross-modal feedback during the electromyographic (EMG) control of a prosthetic hand, testing results show that users are able to use audial feedback alone to discriminate between everyday objects. While users showed adaptation to three different frequency maps, the simplest map containing only two frequencies was found to be the most useful in discriminating between objects. This outcome provides support for the feasibility and practicality of the cross-modal feedback method during the neural control of prosthetics.

  13. Spontaneous swallowing frequency has potential to identify dysphagia in acute stroke.

    Science.gov (United States)

    Crary, Michael A; Carnaby, Giselle D; Sia, Isaac; Khanna, Anna; Waters, Michael F

    2013-12-01

    Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke. In a cohort of 63 acute stroke cases, swallow frequency rates (swallows per minute [SPM]) were compared with stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with versus without clinically significant dysphagia. Receiver operating characteristic curve analysis was used to identify the optimal threshold in SPM, which was compared with a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was used to identify the minimally adequate time period to complete spontaneous swallow frequency analysis. SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. Receiver operating characteristic curve analysis yielded a threshold of SPM≤0.40 that identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5- to 10-minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke. Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel.

  14. Spontaneous Swallowing Frequency [Has Potential to] Identify Dysphagia in Acute Stroke

    Science.gov (United States)

    Carnaby, Giselle D; Sia, Isaac; Khanna, Anna; Waters, Michael

    2014-01-01

    Background and Purpose Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke. Methods In a cohort of 63 acute stroke cases swallow frequency rates (swallows per minute: SPM) were compared to stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with vs. without clinically significant dysphagia. ROC analysis was used to identify the optimal threshold in SPM which was compared to a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was employed to identify the minimally adequate time period to complete spontaneous swallow frequency analysis. Results SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. ROC analysis yielded a threshold of SPM ≤ 0.40 which identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5 to 10 minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke. Conclusions Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel. PMID:24149008

  15. Staurosporine Inhibits Frequency-Dependent Myofilament Desensitization in Intact Rabbit Cardiac Trabeculae

    Directory of Open Access Journals (Sweden)

    Kenneth D. Varian

    2012-01-01

    Full Text Available Myofilament calcium sensitivity decreases with frequency in intact healthy rabbit trabeculae and associates with Troponin I and Myosin light chain-2 phosphorylation. We here tested whether serine-threonine kinase activity is primarily responsible for this frequency-dependent modulations of myofilament calcium sensitivity. Right ventricular trabeculae were isolated from New Zealand White rabbit hearts and iontophoretically loaded with bis-fura-2. Twitch force-calcium relationships and steady state force-calcium relationships were measured at frequencies of 1 and 4 Hz at 37 °C. Staurosporine (100 nM, a nonspecific serine-threonine kinase inhibitor, or vehicle (DMSO was included in the superfusion solution before and during the contractures. Staurosporine had no frequency-dependent effect on force development, kinetics, calcium transient amplitude, or rate of calcium transient decline. The shift in the pCa50 of the force-calcium relationship was significant from 6.05±0.04 at 1 Hz versus 5.88±0.06 at 4 Hz under control conditions (vehicle, P<0.001 but not in presence of staurosporine (5.89±0.08 at 1 Hz versus 5.94±0.07 at 4 Hz, P=NS. Phosphoprotein analysis (Pro-Q Diamond stain confirmed that staurosporine significantly blunted the frequency-dependent phosphorylation at Troponin I and Myosin light chain-2. We conclude that frequency-dependent modulation of calcium sensitivity is mediated through a kinase-specific effect involving phosphorylation of myofilament proteins.

  16. Static electromagnetic frequency changers

    CERN Document Server

    Rozhanskii, L L

    1963-01-01

    Static Electromagnetic Frequency Changers is about the theory, design, construction, and applications of static electromagnetic frequency changers, devices that used for multiplication or division of alternating current frequency. It is originally published in the Russian language. This book is organized into five chapters. The first three chapters introduce the readers to the principles of operation, the construction, and the potential applications of static electromagnetic frequency changers and to the principles of their design. The two concluding chapters use some hitherto unpublished work

  17. Visuomotor Entrainment and the Frequency-Dependent Response of Walking Balance to Perturbations.

    Science.gov (United States)

    Franz, Jason R; Francis, Carrie; Allen, Matt; Thelen, Darryl G

    2016-08-26

    Visuomotor entrainment, or the synchronization of motor responses to visual stimuli, is a naturally emergent phenomenon in human standing. Our purpose was to investigate the prevalence and resolution of visuomotor entrainment in walking and the frequency-dependent response of walking balance to perturbations. We used a virtual reality environment to manipulate optical flow in ten healthy young adults during treadmill walking. A motion capture system recorded trunk, sacrum, and heel marker trajectories during a series of 3-min conditions in which we perturbed a virtual hallway mediolaterally with systematic changes in the driving frequencies of perceived motion. We quantified visuomotor entrainment using spectral analyses and balance deficits using trunk sway, gait variability, and detrended fluctuation analyses (DFA). ML kinematics were highly sensitive to visual perturbations, and instinctively synchronized (i.e., entrained) to a broad range of driving frequencies of perceived ML motion. However, the influence of visual perturbations on metrics of walking balance was frequency-dependent and governed by their proximity to stride frequency. Specifically, we found that a driving frequency nearest to subjects' average stride frequency uniquely compromised trunk sway, gait variability, and step-to-step correlations. We conclude that visuomotor entrainment is a robust and naturally emerging phenomenon during human walking, involving coordinated and frequency-dependent adjustments in trunk sway and foot placement to maintain balance at the whole-body level. These findings provide mechanistic insight into how the visuomotor control of walking balance is disrupted by visual perturbations and important reference values for the emergence of balance deficits due to age, injury, or disease.

  18. ENVIRONMENTAL SPECIFICATION REQUIREMENTS

    International Nuclear Information System (INIS)

    TIFFT, S.R.

    2003-01-01

    Through regulations, permitting or binding negotiations, Regulators establish requirements, limits, permit conditions and Notice of Construction (NOC) conditions with which the Office of River Protection (ORP) and the Tank Farm Contractor (TFC) must comply. Operating Specifications are technical limits which are set on a process to prevent injury to personnel, or damage to the facility or environment. The main purpose of this document is to provide specification limits and recovery actions for the TFC Environmental Surveillance Program at the Hanford Site. Specification limits are given for monitoring frequencies and permissible variation of readings from an established baseline or previous reading. The requirements in this document are driven by environmental considerations and data analysis issues, rather than facility design or personnel safety issues. This document is applicable to all SST and DST waste tanks, and the associated catch tanks and receiver tanks, and transfer systems. This Tank Farm ESD implements environmental-regulatory limits on the configuration and operation of the Hanford Tank Farms facility that have been established by Regulators. This ESD contains specific field operational limits and recovery actions for compliance with airborne effluent regulations and agreements, liquid effluents regulations and agreements, and environmental tank system requirements. The scope of this ESD is limited to conditions that have direct impact on Operations/Projects or that Operations/Projects have direct impact upon. This document does not supercede or replace any DOE Orders, regulatory permits, notices of construction, or Regulatory agency agreements binding on the ORP or the TFC. Refer to the appropriate regulation, permit, or NOC for an inclusive listing of requirements

  19. Robust Frequency-Domain Constrained Feedback Design via a Two-Stage Heuristic Approach.

    Science.gov (United States)

    Li, Xianwei; Gao, Huijun

    2015-10-01

    Based on a two-stage heuristic method, this paper is concerned with the design of robust feedback controllers with restricted frequency-domain specifications (RFDSs) for uncertain linear discrete-time systems. Polytopic uncertainties are assumed to enter all the system matrices, while RFDSs are motivated by the fact that practical design specifications are often described in restricted finite frequency ranges. Dilated multipliers are first introduced to relax the generalized Kalman-Yakubovich-Popov lemma for output feedback controller synthesis and robust performance analysis. Then a two-stage approach to output feedback controller synthesis is proposed: at the first stage, a robust full-information (FI) controller is designed, which is used to construct a required output feedback controller at the second stage. To improve the solvability of the synthesis method, heuristic iterative algorithms are further formulated for exploring the feedback gain and optimizing the initial FI controller at the individual stage. The effectiveness of the proposed design method is finally demonstrated by the application to active control of suspension systems.

  20. [Frequency of skin reactivity to food allergens in allergic patients].

    Science.gov (United States)

    Camero-Martínez, Heriberto; López-García, Aída Inés; Rivero-Yeverino, Daniela; Caballero-López, Chrystopherson Gengyny; Arana-Muñoz, Oswaldo; Papaqui-Tapia, Sergio; Rojas-Méndez, Isabel Cristina; Vázquez-Rojas, Elizabeth

    2017-01-01

    Food allergy is deemed to have a worldwide prevalence ranging from 2 to 10 %. To determine the frequency of skin reactivity to food allergens by age groups. Cross-sectional, descriptive, prolective, observational study. Patients aged from 2 to 64 years with symptoms consistent with allergic disease were included. Skin prick tests were carried out with food allergens. Frequencies and percentages were estimated. One-hundred and ninety-one patients were included, out of which 63.4% were females. Mean age was 22.5 years; 19.3 % showed positive skin reactivity to at least one food. Distribution by age group was as follows: preschool children 13.5 %, schoolchildren 24.3 %, adolescents 2.7 % and adults 59.5 %. Diagnoses included allergic rhinitis in 84.3 %, asthma in 19.4 %, urticaria in 14.1 % and atopic dermatitis in 8.4 %. Positive skin reactivity frequency distribution in descending order was: soybeans with 5.2 %, peach with 4.7 %, grapes, orange and apple with 3.6 %, nuts with 3.1 %, pineapple, avocado, tomato and tuna with 2.6 %. The frequency of skin reactivity to food allergens was similar to that reported in the national and Latin American literature, but sensitization to each specific allergen varied for each age group.

  1. Pump-probe nonlinear magneto-optical rotation with frequency-modulated light

    International Nuclear Information System (INIS)

    Pustelny, S.; Gawlik, W.; Jackson Kimball, D. F.; Rochester, S. M.; Yashchuk, V. V.; Budker, D.

    2006-01-01

    Specific types of atomic coherences between Zeeman sublevels can be generated and detected using a method based on nonlinear magneto-optical rotation with frequency-modulated light. Linearly polarized, frequency-modulated light is employed to selectively generate ground-state coherences between Zeeman sublevels for which Δm=2 and Δm=4 in 85 Rb and 87 Rb atoms, and additionally Δm=6 in 85 Rb. The atomic coherences are detected with a separate, unmodulated probe light beam. Separation of the pump and probe beams enables independent investigation of the processes of creation and detection of the atomic coherences. With the present technique the transfer of the Zeeman coherences, including high-order coherences, from excited to ground state by spontaneous emission has been observed

  2. Human frequency-following response to speech-like sounds: correlates of off-frequency masking.

    Science.gov (United States)

    Krishnan, Ananthanarayan; Agrawal, Smita

    2010-01-01

    Off-frequency masking of the second formant by energy at the first formant has been shown to influence both identification and discrimination of the second formant in normal-hearing and hearing-impaired listeners. While both excitatory spread and two-tone suppression have been implicated in this simultaneous masking, their relative contribution has been shown to depend on both the level of the masker and the frequency separation between the probe and the masker. Off-frequency masking effects were evaluated in 10 normal-hearing human adults using the frequency-following response (FFR) to two two-tone approximations of vowel stimuli (/a/ and /u/). In the first experiment, the masking effect of F(1) on F(2) was evaluated by attenuating the level of F(1) relative to a fixed F(2) level. In the second experiment, the masking effect was evaluated by increasing the frequency separation between F(1) and F(2) using F(2) frequency as the variable. Results revealed that both attenuation of the F(1) level, and increasing the frequency separation between F(1) and F(2) increased the magnitude of the FFR component at F(2). These results are consistent with a release from off-frequency masking. Given that the results presented here are for high signal and masker levels and for relatively smaller frequency separation between the masker and the probe, it is possible that both suppression and excitatory spread contributed to the masking effects observed in our data. Copyright2009 S. Karger AG, Basel.

  3. Scheme for efficient extraction of low-frequency signal beyond the quantum limit by frequency-shift detection.

    Science.gov (United States)

    Yang, R G; Zhang, J; Zhai, Z H; Zhai, S Q; Liu, K; Gao, J R

    2015-08-10

    Low-frequency (Hz~kHz) squeezing is very important in many schemes of quantum precision measurement. But it is more difficult than that at megahertz-frequency because of the introduction of laser low-frequency technical noise. In this paper, we propose a scheme to obtain a low-frequency signal beyond the quantum limit from the frequency comb in a non-degenerate frequency and degenerate polarization optical parametric amplifier (NOPA) operating below threshold with type I phase matching by frequency-shift detection. Low-frequency squeezing immune to laser technical noise is obtained by a detection system with a local beam of two-frequency intense laser. Furthermore, the low-frequency squeezing can be used for phase measurement in Mach-Zehnder interferometer, and the signal-to-noise ratio (SNR) can be enhanced greatly.

  4. Low band gap frequencies and multiplexing properties in 1D and 2D mass spring structures

    International Nuclear Information System (INIS)

    Aly, Arafa H; Mehaney, Ahmed

    2016-01-01

    This study reports on the propagation of elastic waves in 1D and 2D mass spring structures. An analytical and computation model is presented for the 1D and 2D mass spring systems with different examples. An enhancement in the band gap values was obtained by modeling the structures to obtain low frequency band gaps at small dimensions. Additionally, the evolution of the band gap as a function of mass value is discussed. Special attention is devoted to the local resonance property in frequency ranges within the gaps in the band structure for the corresponding infinite periodic lattice in the 1D and 2D mass spring system. A linear defect formed of a row of specific masses produces an elastic waveguide that transmits at the narrow pass band frequency. The frequency of the waveguides can be selected by adjusting the mass and stiffness coefficients of the materials constituting the waveguide. Moreover, we pay more attention to analyze the wave multiplexer and DE-multiplexer in the 2D mass spring system. We show that two of these tunable waveguides with alternating materials can be employed to filter and separate specific frequencies from a broad band input signal. The presented simulation data is validated through comparison with the published research, and can be extended in the development of resonators and MEMS verification. (paper)

  5. An Extended System Frequency Response Model Considering Wind Power Participation in Frequency Regulation

    Directory of Open Access Journals (Sweden)

    Yi Tang

    2017-11-01

    Full Text Available With increasing penetration of wind power into the power system, wind power participation in frequency regulation is regarded as a beneficial strategy to improve the dynamic frequency response characteristics of power systems. The traditional power system frequency response (SFR model, which only includes synchronous generators, is no longer suitable for power systems with high penetrated wind power. An extended SFR model, based on the reduced-order model of wind turbine generator (WTG and the traditional SFR model, is presented in this paper. In the extended SFR model, the reduced-order model of WTG with combined frequency control is deduced by employing small signal analysis theory. Afterwards, the stability analysis of a closed-loop control system for the extended SFR model is carried out. Time-domain simulations using a test system are performed to validate the effectiveness of the extended SFR model; this model can provide a simpler, clearer and faster way to analyze the dynamic frequency response characteristic for a high-wind integrated power systems. The impact of additional frequency control parameters and wind speed disturbances on the system dynamic frequency response characteristics are investigated.

  6. Effects of concomitant temozolomide and radiation therapies on WT1-specific T-cells in malignant glioma

    International Nuclear Information System (INIS)

    Chiba, Yasuyoshi; Hashimoto, Naoya; Tsuboi, Akihiro

    2010-01-01

    Immunotherapy targeting the Wilms' tumour 1 gene product has been proven safe and effective for treating malignant glioma in a phase II clinical study. Currently, radiation/temozolomide therapy is the standard treatment with only modest benefit. Whether combining radiation/temozolomide therapy with WT1 immunotherapy will have a negating effect on immunotherapy is still controversial because of the significant lymphocytopaenia induced by the former therapy. To address this issue, we investigated the changes in frequency and number of WT1-specific T-cells in patients with malignant gliomas. Twenty-two patients with newly diagnosed malignant glioma who received standard radiation/temozolomide therapy were recruited for the study. Blood samples were collected before treatment and on the sixth week of therapy. The frequencies and numbers of lymphocytes, CD8 + T-cells, WT1-specific T-cells, regulatory T-cells, natural killer cells and natural killer T-cells were measured and analysed using T-tests. Analysis of the frequency of T lymphocytes and its subpopulation showed an increase in regulatory T-cells, but no significant change was noted in the populations of T-cells, WT1-specific T-cells, natural killer (NK) cells and natural killer T (NKT) cells. Reductions in the total numbers of T-cells, WT1-specific T-cells, NK cells and NKT cells were mainly a consequence of the decrease in the total lymphocyte count. Radiation/temozolomide therapy did not significantly affect the frequency of WT1-specific T-cells, suggesting that the combination with WT1 immunotherapy may be possible, although further assessment in the clinical setting is warranted. (author)

  7. Resting-state functional under-connectivity within and between large-scale cortical networks across three low-frequency bands in adolescents with autism.

    Science.gov (United States)

    Duan, Xujun; Chen, Heng; He, Changchun; Long, Zhiliang; Guo, Xiaonan; Zhou, Yuanyue; Uddin, Lucina Q; Chen, Huafu

    2017-10-03

    Although evidence is accumulating that autism spectrum disorder (ASD) is associated with disruption of functional connections between and within brain networks, it remains largely unknown whether these abnormalities are related to specific frequency bands. To address this question, network contingency analysis was performed on brain functional connectomes obtained from 213 adolescent participants across nine sites in the Autism Brain Imaging Data Exchange (ABIDE) multisite sample, to determine the disrupted connections between and within seven major cortical networks in adolescents with ASD at Slow-5, Slow-4 and Slow-3 frequency bands and further assess whether the aberrant intra- and inter-network connectivity varied as a function of ASD symptoms. Overall under-connectivity within and between large-scale intrinsic networks in ASD was revealed across the three frequency bands. Specifically, decreased connectivity strength within the default mode network (DMN), between DMN and visual network (VN), ventral attention network (VAN), and between dorsal attention network (DAN) and VAN was observed in the lower frequency band (slow-5, slow-4), while decreased connectivity between limbic network (LN) and frontal-parietal network (FPN) was observed in the higher frequency band (slow-3). Furthermore, weaker connectivity within and between specific networks correlated with poorer communication and social interaction skills in the slow-5 band, uniquely. These results demonstrate intrinsic under-connectivity within and between multiple brain networks within predefined frequency bands in ASD, suggesting that frequency-related properties underlie abnormal brain network organization in the disorder. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. RELATIONSHIP BETWEEN LOW AND HIGH FREQUENCIES IN δ SCUTI STARS: PHOTOMETRIC KEPLER AND SPECTROSCOPIC ANALYSES OF THE RAPID ROTATOR KIC 8054146

    International Nuclear Information System (INIS)

    Breger, M.; Robertson, P.; Fossati, L.; Balona, L.; Kurtz, D. W.; Bohlender, D.; Lenz, P.; Müller, I.; Lüftinger, Th.; Clarke, Bruce D.; Hall, Jennifer R.; Ibrahim, Khadeejah A.

    2012-01-01

    Two years of Kepler data of KIC 8054146 (δ Sct/γ Dor hybrid) revealed 349 statistically significant frequencies between 0.54 and 191.36 cycles day –1 (6.3 μHz to 2.21 mHz). The 117 low frequencies cluster in specific frequency bands, but do not show the equidistant period spacings predicted for gravity modes of successive radial order, n, and reported for at least one other hybrid pulsator. The four dominant low frequencies in the 2.8-3.0 cycles day –1 (32-35 μHz) range show strong amplitude variability with timescales of months and years. These four low frequencies also determine the spacing of the higher frequencies in and beyond the δ Sct pressure-mode frequency domain. In fact, most of the higher frequencies belong to one of three families with spacings linked to a specific dominant low frequency. In the Fourier spectrum, these family regularities show up as triplets, high-frequency sequences with absolutely equidistant frequency spacings, side lobes (amplitude modulations), and other regularities in frequency spacings. Furthermore, within two families the amplitude variations between the low and high frequencies are related. We conclude that the low frequencies (gravity modes, rotation) and observed high frequencies (mostly pressure modes) are physically connected. This unusual behavior may be related to the very rapid rotation of the star: from a combination of high- and low-resolution spectroscopy we determined that KIC 8054146 is a very fast rotator (υ sin i = 300 ± 20 km s –1 ) with an effective temperature of 7600 ± 200 K and a surface gravity log g of 3.9 ± 0.3. Several astrophysical ideas explaining the origin of the relationship between the low and high frequencies are explored.

  9. Genome of the Netherlands population-specific imputations identify an ABCA6 variant associated with cholesterol levels

    NARCIS (Netherlands)

    van Leeuwen, E.M.; Karssen, L.C.; Deelen, J.; Isaacs, A.; Medina-Gomez, C.; Mbarek, H.; Kanterakis, A.; Trompet, S.; Postmus, I.; Verweij, N.; van Enckevort, D.; Huffman, J.E.; White, C.C.; Feitosa, M.F.; Bartz, T.M.; Manichaikul, A.; Joshi, P.K.; Peloso, G.M.; Deelen, P.; Dijk, F.; Willemsen, G.; de Geus, E.J.C.; Milaneschi, Y.; Penninx, B.W.J.H.; Francioli, L.C.; Menelaou, A.; Pulit, S.L.; Rivadeneira, F.; Hofman, A.; Oostra, B.A.; Franco, O.H.; Mateo Leach, I.; Beekman, M.; de Craen, A.J.; Uh, H.W.; Trochet, H.; Hocking, L.J.; Porteous, D.J.; Sattar, N.; Packard, C.J.; Buckley, B.M.; Brody, J.A.; Bis, J.C.; Rotter, J.I.; Mychaleckyj, J.C.; Campbell, H.; Duan, Q.; Lange, L.A.; Wilson, J.F.; Hayward, C.; Polasek, O.; Vitart, V.; Rudan, I.; Wright, A.F.; Rich, S.S.; Psaty, B.M.; Borecki, I.B.; Kearney, P.M.; Stott, D.J.; Cupples, L.A.; Jukema, J.W.; van der Harst, P.; Sijbrands, E.J.; Hottenga, J.J.; Uitterlinden, A.G.; Swertz, M.A.; van Ommen, G.J.B; Bakker, P.I.W.; Slagboom, P.E.; Boomsma, D.I.; Wijmenga, C.; van Duijn, C.M.

    2015-01-01

    Variants associated with blood lipid levels may be population-specific. To identify low-frequency variants associated with this phenotype, population-specific reference panels may be used. Here we impute nine large Dutch biobanks (∼35,000 samples) with the population-specific reference panel created

  10. Vibro-Shock Dynamics Analysis of a Tandem Low Frequency Resonator—High Frequency Piezoelectric Energy Harvester

    Directory of Open Access Journals (Sweden)

    Darius Žižys

    2017-04-01

    Full Text Available Frequency up-conversion is a promising technique for energy harvesting in low frequency environments. In this approach, abundantly available environmental motion energy is absorbed by a Low Frequency Resonator (LFR which transfers it to a high frequency Piezoelectric Vibration Energy Harvester (PVEH via impact or magnetic coupling. As a result, a decaying alternating output signal is produced, that can later be collected using a battery or be transferred directly to the electric load. The paper reports an impact-coupled frequency up-converting tandem setup with different LFR to PVEH natural frequency ratios and varying contact point location along the length of the harvester. RMS power output of different frequency up-converting tandems with optimal resistive values was found from the transient analysis revealing a strong relation between power output and LFR-PVEH natural frequency ratio as well as impact point location. Simulations revealed that higher power output is obtained from a higher natural frequency ratio between LFR and PVEH, an increase of power output by one order of magnitude for a doubled natural frequency ratio and up to 150% difference in power output from different impact point locations. The theoretical results were experimentally verified.

  11. ISM band to U-NII band frequency transverter and method of frequency transversion

    Science.gov (United States)

    Stepp, Jeffrey David [Grandview, MO; Hensley, Dale [Grandview, MO

    2006-09-12

    A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz 6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

  12. Peripheral Circulatory Features during High-Frequency Jet Ventilation

    Directory of Open Access Journals (Sweden)

    M. B. Kontorovich

    2010-01-01

    Full Text Available The paper gives the results of a study of peripheral circulatory features during high-frequency jet ventilation (HFJV. The main specific features of peripheral circulation and oxygen transport during HFJV are formulated on the basis of a study of cardiac output (impedance cardiography, peripheral vascular resistance, peripheral vascular blood filling (photoplethysmogram analysis, adaptive peripheral blood flow reactions (spectral analysis of peripheral vascular pulsation. HFJV gives rise to the peculiar pattern of peripheral hemodynamics and tissue gas exchange, which is characterized by higher oxygen uptake without a decrease in mixed venous blood saturation, with normal extraction coefficient and preserved low peripheral vascular resistance. During HFJV, unlike traditional ventilation, the main peripheral hemodynamic feature is the increased capillary bed blood volume caused by the blood flow involvement of reserve capillaries under control of volume (parasympathetic regulation of adaptive peripheral hemodynamic reactions. Key words: high-frequency jet ventilation, oxygen transport, peripheral hemodynamics.

  13. Frequency distributions from birth, death, and creation processes.

    Science.gov (United States)

    Bartley, David L; Ogden, Trevor; Song, Ruiguang

    2002-01-01

    The time-dependent frequency distribution of groups of individuals versus group size was investigated within a continuum approximation, assuming a simplified individual growth, death and creation model. The analogy of the system to a physical fluid exhibiting both convection and diffusion was exploited in obtaining various solutions to the distribution equation. A general solution was approximated through the application of a Green's function. More specific exact solutions were also found to be useful. The solutions were continually checked against the continuum approximation through extensive simulation of the discrete system. Over limited ranges of group size, the frequency distributions were shown to closely exhibit a power-law dependence on group size, as found in many realizations of this type of system, ranging from colonies of mutated bacteria to the distribution of surnames in a given population. As an example, the modeled distributions were successfully fit to the distribution of surnames in several countries by adjusting the parameters specifying growth, death and creation rates.

  14. Sum frequency generation for studying plasma-wall interactions

    International Nuclear Information System (INIS)

    Roke, Sylvie

    2010-01-01

    Interaction of a plasma with a surface results in chemical and physical restructuring of the surface as well as the plasma in the vicinity of the surface. Studying such a reorganization of the atoms and molecules in the surface layer requires optical tools that can penetrate the plasma environment. At the same time, surface specificity is required. Sum Frequency Generation (SFG) is an optical method that fulfills these requirements. SFG has been developed into a surface specific probe during the eighties and nineties. Nowadays SFG is routinely applied in the research of complex interfaces. In such experiments, liquid/gas, solid/gas, solid/liquid, or liquid/liquid interfaces are probed, and the chemical surface composition, orientational distribution, order and chirality can be retrieved. An application to investigate plasma-wall interactions is feasible too.

  15. IL10 low-frequency variants in Behçet's disease patients.

    Science.gov (United States)

    Matos, Mafalda; Xavier, Joana M; Abrantes, Patrícia; Sousa, Inês; Rei, Nádia; Davatchi, Fereydoun; Shahram, Farhad; Jesus, Gorete; Barcelos, Filipe; Vedes, Joana; Salgado, Manuel; Abdollahi, Bahar Sadeghi; Nadji, Abdolhadi; Moraes-Fontes, Maria Francisca; Shafiee, Niloofar Mojarad; Ghaderibarmi, Fahmida; Vaz Patto, José; Crespo, Jorge; Oliveira, Sofia A

    2017-05-01

    To explain the missing heritability after the genome-wide association studies era, sequencing studies allow the identification of low-frequency variants with a stronger effect on disease risk. Common variants in the interleukin 10 gene (IL10) have been consistently associated with Behçet's disease (BD) and the goal of this study is to investigate the role of low-frequency IL10 variants in BD susceptibility. To identify IL10 low-frequency variants, a discovery group of 50 Portuguese BD patients were Sanger-sequenced in a 7.7 kb genomic region encompassing the complete IL10 gene, 0.9 kb upstream and 2 kb downstream, and two conserved regions in the putative promoter. To assess if the novel variants are BD- and/or Portuguese-specific, they were assayed in an additional group of BD patients (26 Portuguese and 964 Iranian) and controls (104 Portuguese and 823 Iranian). Rare IL10 coding variants were not detected in BD patients, but we identified 28 known single nucleotide polymorphisms with minor allele frequencies ranging from 0.010 to 0.390, and five novel non-coding variants in five heterozygous cases. ss836185595, located in the IL10 3' untranslated region, was also detected in one Iranian control individual and therefore is not specific to BD. The remaining novel IL10 variants (ss836185596 and ss836185602 in intron 3, ss836185598 and ss836185604 in the putative promoter region) were not found in the replication dataset. This study highlights the importance of screening the whole gene and regulatory regions when searching for novel variants associated with complex diseases, and the need to develop bioinformatics tools to predict the functional impact of non-coding variants and statistical tests which incorporate these predictions. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

  16. HIGHER MODE FREQUENCY EFFECTS ON RESONANCE IN MACHINERY, STRUCTURES, AND PIPE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R.

    2010-05-02

    The complexities of resonance in multi-degree of freedom systems (multi-DOF) may be clarified using graphic presentations. Multi-DOF systems represent actual systems, such as beams or springs, where multiple, higher order, natural frequencies occur. Resonance occurs when a cyclic load is applied to a structure, and the frequency of the applied load equals one of the natural frequencies. Both equations and graphic presentations are available in the literature for single degree of freedom (SDOF) systems, which describe the response of spring-mass-damper systems to harmonically applied, or cyclic, loads. Loads may be forces, moments, or forced displacements applied to one end of a structure. Multi-DOF systems are typically described only by equations in the literature, and while equations certainly permit a case by case analysis for specific conditions, graphs provide an overall comprehension not gleaned from single equations. In fact, this collection of graphed equations provides novel results, which describe the interactions between multiple natural frequencies, as well as a comprehensive description of increased vibrations near resonance.

  17. CAMAC programmable-control frequency synthesizer

    International Nuclear Information System (INIS)

    Yumaguzin, T.Kh.; Vyazovkin, D.E.; Nazirov, Eh.P.; Tuktarov, R.F.

    1989-01-01

    Synthesizer allows to set frequency with 0.015% accuracy and to scan it with variable step. Frequency controlled divider with further summing-up of divided frequency with fundamental one is used in synthesizer, and it has allowed to use digit of the input code and to obtain 3-4 MHz frequency range. Variation of operation flowsheet in the other frequency range is possible. K-155 and K-531 series microcircuits were used during development

  18. Mixed Frequency Data Sampling Regression Models: The R Package midasr

    Directory of Open Access Journals (Sweden)

    Eric Ghysels

    2016-08-01

    Full Text Available When modeling economic relationships it is increasingly common to encounter data sampled at different frequencies. We introduce the R package midasr which enables estimating regression models with variables sampled at different frequencies within a MIDAS regression framework put forward in work by Ghysels, Santa-Clara, and Valkanov (2002. In this article we define a general autoregressive MIDAS regression model with multiple variables of different frequencies and show how it can be specified using the familiar R formula interface and estimated using various optimization methods chosen by the researcher. We discuss how to check the validity of the estimated model both in terms of numerical convergence and statistical adequacy of a chosen regression specification, how to perform model selection based on a information criterion, how to assess forecasting accuracy of the MIDAS regression model and how to obtain a forecast aggregation of different MIDAS regression models. We illustrate the capabilities of the package with a simulated MIDAS regression model and give two empirical examples of application of MIDAS regression.

  19. Low frequency vibrations disrupt left-right patterning in the Xenopus embryo.

    Directory of Open Access Journals (Sweden)

    Laura N Vandenberg

    Full Text Available The development of consistent left-right (LR asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure to several low frequencies induced specific randomization of three internal organs (heterotaxia. Investigating one frequency (7 Hz, we found two discrete periods of sensitivity to vibration; during the first period, vibration affected the same LR pathway as nocodazole, while during the second period, vibration affected the integrity of the epithelial barrier; both are required for normal LR patterning. Our results indicate that low frequency vibrations disrupt two steps in the early LR pathway: the orientation of the LR axis with the other two axes, and the amplification/restriction of downstream LR signals to asymmetric organs.

  20. High-frequency collocations of nouns in research articles across eight disciplines

    Directory of Open Access Journals (Sweden)

    Matthew Peacock

    2012-04-01

    Full Text Available This paper describes a corpus-based analysis of the distribution of the high-frequency collocates of abstract nouns in 320 research articles across eight disciplines: Chemistry, Computer Science, Materials Science, Neuroscience, Economics, Language and Linguistics, Management, and Psychology. Disciplinary variation was also examined – very little previous research seems to have investigated this. The corpus was analysed using WordSmith Tools. The 16 highest-frequency nouns across all eight disciplines were identified, followed by the highest-frequency collocates for each noun. Five disciplines showed over 50% variance from the overall results. Conclusions are that the differing patterns revealed are disciplinary norms and represent standard terminology within the disciplines arising from the topics discussed, research methods, and content of discussions. It is also concluded that the collocations are an important part of the meanings and functions of the nouns, and that this evidence of sharp discipline differences underlines the importance of discipline-specific collocation research.

  1. Hg(+) Frequency Standards

    Science.gov (United States)

    Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2000-01-01

    In this paper we review the development of Hg(+) microwave frequency standards for use in high reliability and continuous operation applications. In recent work we have demonstrated short-term frequency stability of 3 x 10(exp -14)/nu(sub tau) when a cryogenic oscillator of stability 2-3 x 10(exp 15) was used a the local oscillator. The trapped ion frequency standard employs a Hg-202 discharge lamp to optically pump the trapped Hg(+)-199 clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg(+) ion trap based frequency standard with an extended linear ion trap (LITE) architecture which separates the optical state selection region from the clock resonance region. This separation allows the use of novel trap configurations in the resonance region since no optical pumping is carried out there. A method for measuring the size of an ion cloud inside a linear trap with a 12-rod trap is currently being investigated. At approx. 10(exp -12), the 2nd order Doppler shift for trapped mercury ion frequency standards is one of the largest frequency offsets and its measurement to the 1% level would represent an advance in insuring the very long-term stability of these standards to the 10(exp -14) or better level. Finally, we describe atomic clock comparison experiments that can probe for a time variation of the fine structure constant, alpha = e(exp 2)/2(pi)hc, at the level of 10(exp -20)/year as predicted in some Grand Unified String Theories.

  2. Microwave Frequency Multiplier

    Science.gov (United States)

    Velazco, J. E.

    2017-02-01

    High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1 to 8.6 GHz) microwave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34 to 36 GHz) in order to achieve higher target resolution. Current commercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2 to 8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the second cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity's frequency. Frequency multiplication factors in the 4 to 10 range are being considered for the current application, although higher multiplication factors are feasible. This novel beam-wave interaction allows the MFM to produce high-power, high-frequency radiation with high efficiency. A key feature of the MFM is that it uses significantly larger cavities than its klystron counterparts, thus greatly reducing power density and arcing

  3. Dependence of synchronization frequency of Kuramoto oscillators on symmetry of intrinsic frequency in ring network

    Science.gov (United States)

    Saha, Arindam; Amritkar, R. E.

    2014-12-01

    Kuramoto oscillators have been proposed earlier as a model for interacting systems that exhibit synchronisation. In this article we study the difference between networks with symmetric and asymmetric distribution of natural frequencies. We first indicate that the synchronisation frequency of the oscillators is independent of the natural frequency distribution for a completely connected network. Further we analyse the case of oscillators in a directed ring-network where asymmetry in the natural frequency distribution is seen to shift the synchronisation frequency of the network. We also present an estimate of the shift in the frequencies for slightly asymmetric distributions.

  4. Band Width of Acoustic Resonance Frequency Relatively Natural Frequency of Fuel Rod Vibration

    Energy Technology Data Exchange (ETDEWEB)

    Proskuryakov, Konstantin Nicolaevich; Moukhine, V.S.; Novikov, K.S.; Galivets, E.Yu. [MPEI - TU, 14, Krasnokazarmennaya str., Moscow, 111250 (Russian Federation)

    2009-06-15

    In flow induced vibrations the fluid flow is the energy source that causes vibration. Acoustic resonance in piping may lead to severe problems due to over-stressing of components or significant losses of efficiency. Steady oscillatory flow in NPP primary loop can be induced by the pulsating flow introduced by reactor circulating pump or may be set up by self-excitation. Dynamic forces generated by the turbulent flow of coolant in reactor cores cause fuel rods (FR) and fuel assembly (FA) to vibrate. Flow-induced FR and FA vibrations can generally be broken into three groups: large amplitude 'resonance type' vibrations, which can cause immediate rod failure or severe damage to the rod and its support structure, middle amplitude 'within bandwidth of resonance frequency type' vibrations responsible for more gradual wear and fatigue at the contact surface between the fuel cladding and rod support and small amplitude vibrations, 'out of bandwidth of resonance frequency type' responsible for permissible wear and fatigue at the contact surface between the fuel cladding and rod support. Ultimately, these vibration types can result in a cladding breach, and therefore must be accounted for in the thermal hydraulic design of FR and FA and reactor internals. In paper the technique of definition of quality factor (Q) of acoustic contour of the coolant is presented. The value of Q defines a range of frequencies of acoustic fluctuations of the coolant within which the resonance of oscillations of the structure and the coolant is realized. Method of evaluation of so called band width (BW) of acoustic resonance frequency is worked out and presented in the paper. BW characterises the range of the frequency of coolant pressure oscillations within which the frequency of coolant pressure oscillations matches the fuel assembly's natural frequency of vibration (its resonance frequency). Paper show the way of detuning acoustic resonance from natural

  5. Electrothermal frequency reference

    NARCIS (Netherlands)

    Makinwa, K.A.A.; Kashmiri, S.M.

    2011-01-01

    An electrothermal frequency-locked loop (EFLL) circuit is described. This EFLL circuit includes an oscillator in a feedback loop. A drive circuit in the EFLL circuit generates a first signal having a fundamental frequency, and an electrothermal filter (ETF) in the EFLL circuit provides a second

  6. Management Process of a Frequency Response Flight Test for Rotorcraft Flying Qualities Evaluation

    Directory of Open Access Journals (Sweden)

    João Otávio Falcão Arantes Filho

    2016-07-01

    Full Text Available This paper applies the frequency response methodology to characterize and analyze the flying qualities of longitudinal and lateral axes of a rotary-wing aircraft, AS355-F2. Using the results, it is possible to check the suitability of the aircraft in accordance with ADS-33E-PRF standard, whose flying qualities specifications criteria are based on parameters in the frequency domain. The key steps addressed in the study involve getting, by means of flight test data, the closed-loop dynamic responses including the design of the instrumentation and specification of the sensors to be used in the flight test campaign, the definition of the appropriate maneuvers characteristics for excitation of the aircraft, the planning and execution of the flight test to collect the data, and the proper data treatment, processing and analysis after the flight. After treatment of the collected data, single input-single output spectral analysis is performed. The results permit the analysis of the flying qualities characteristics, anticipation of the demands to which the pilot will be subjected during closed-loop evaluations and check of compliance with the aforementioned standard, within the range of consistent excitation frequencies for flight tests, setting the agility level of the test aircraft.

  7. Maximum Entropy, Word-Frequency, Chinese Characters, and Multiple Meanings

    Science.gov (United States)

    Yan, Xiaoyong; Minnhagen, Petter

    2015-01-01

    The word-frequency distribution of a text written by an author is well accounted for by a maximum entropy distribution, the RGF (random group formation)-prediction. The RGF-distribution is completely determined by the a priori values of the total number of words in the text (M), the number of distinct words (N) and the number of repetitions of the most common word (kmax). It is here shown that this maximum entropy prediction also describes a text written in Chinese characters. In particular it is shown that although the same Chinese text written in words and Chinese characters have quite differently shaped distributions, they are nevertheless both well predicted by their respective three a priori characteristic values. It is pointed out that this is analogous to the change in the shape of the distribution when translating a given text to another language. Another consequence of the RGF-prediction is that taking a part of a long text will change the input parameters (M, N, kmax) and consequently also the shape of the frequency distribution. This is explicitly confirmed for texts written in Chinese characters. Since the RGF-prediction has no system-specific information beyond the three a priori values (M, N, kmax), any specific language characteristic has to be sought in systematic deviations from the RGF-prediction and the measured frequencies. One such systematic deviation is identified and, through a statistical information theoretical argument and an extended RGF-model, it is proposed that this deviation is caused by multiple meanings of Chinese characters. The effect is stronger for Chinese characters than for Chinese words. The relation between Zipf’s law, the Simon-model for texts and the present results are discussed. PMID:25955175

  8. Frequency-Dependent Tidal Triggering of Low Frequency Earthquakes Near Parkfield, California

    Science.gov (United States)

    Xue, L.; Burgmann, R.; Shelly, D. R.

    2017-12-01

    The effect of small periodic stress perturbations on earthquake generation is not clear, however, the rate of low-frequency earthquakes (LFEs) near Parkfield, California has been found to be strongly correlated with solid earth tides. Laboratory experiments and theoretical analyses show that the period of imposed forcing and source properties affect the sensitivity to triggering and the phase relation of the peak seismicity rate and the periodic stress, but frequency-dependent triggering has not been quantitatively explored in the field. Tidal forcing acts over a wide range of frequencies, therefore the sensitivity to tidal triggering of LFEs provides a good probe to the physical mechanisms affecting earthquake generation. In this study, we consider the tidal triggering of LFEs near Parkfield, California since 2001. We find the LFEs rate is correlated with tidal shear stress, normal stress rate and shear stress rate. The occurrence of LFEs can also be independently modulated by groups of tidal constituents at semi-diurnal, diurnal and fortnightly frequencies. The strength of the response of LFEs to the different tidal constituents varies between LFE families. Each LFE family has an optimal triggering frequency, which does not appear to be depth dependent or systematically related to other known properties. This suggests the period of the applied forcing plays an important role in the triggering process, and the interaction of periods of loading history and source region properties, such as friction, effective normal stress and pore fluid pressure, produces the observed frequency-dependent tidal triggering of LFEs.

  9. Some recent multi-frequency electron paramagnetic resonance results on systems relevant for dosimetry and dating.

    Science.gov (United States)

    Callens, F; Vanhaelewyn, G; Matthys, P

    2002-04-01

    Electron Paramagnetic Resonance (EPR) applications like e.g. EPR dosimetry and dating, are usually performed at X-band frequencies because of practical reasons (cost, sample size, etc.). However, it is increasingly recognized that the radiation-induced EPR signals are strongly composite, what might affect dose/age estimates. A few recent examples from both the dosimetry and dating field, illustrating the problems, will be presented. The involved spectra are mainly due to carbonate-derived radicals (CO2-, CO3(3-), etc.). Measurements at higher microwave frequencies are often recommended to improve the insight into the spectra and/or the practical signal quantification. Recent results at Q- and W-band frequencies will show that a multi-frequency approach indeed opens many interesting perspectives in this field but also that each frequency may have specific (dis)advantages depending on the EPR probe and application involved. The discussion will concern carbonate-containing apatite single crystals, shells, modern and fossil tooth enamel.

  10. The Influence of High-Frequency Envelope Information on Low-Frequency Vowel Identification in Noise.

    Directory of Open Access Journals (Sweden)

    Wiebke Schubotz

    Full Text Available Vowel identification in noise using consonant-vowel-consonant (CVC logatomes was used to investigate a possible interplay of speech information from different frequency regions. It was hypothesized that the periodicity conveyed by the temporal envelope of a high frequency stimulus can enhance the use of the information carried by auditory channels in the low-frequency region that share the same periodicity. It was further hypothesized that this acts as a strobe-like mechanism and would increase the signal-to-noise ratio for the voiced parts of the CVCs. In a first experiment, different high-frequency cues were provided to test this hypothesis, whereas a second experiment examined more closely the role of amplitude modulations and intact phase information within the high-frequency region (4-8 kHz. CVCs were either natural or vocoded speech (both limited to a low-pass cutoff-frequency of 2.5 kHz and were presented in stationary 3-kHz low-pass filtered masking noise. The experimental results did not support the hypothesized use of periodicity information for aiding low-frequency perception.

  11. The Influence of High-Frequency Envelope Information on Low-Frequency Vowel Identification in Noise.

    Science.gov (United States)

    Schubotz, Wiebke; Brand, Thomas; Kollmeier, Birger; Ewert, Stephan D

    2016-01-01

    Vowel identification in noise using consonant-vowel-consonant (CVC) logatomes was used to investigate a possible interplay of speech information from different frequency regions. It was hypothesized that the periodicity conveyed by the temporal envelope of a high frequency stimulus can enhance the use of the information carried by auditory channels in the low-frequency region that share the same periodicity. It was further hypothesized that this acts as a strobe-like mechanism and would increase the signal-to-noise ratio for the voiced parts of the CVCs. In a first experiment, different high-frequency cues were provided to test this hypothesis, whereas a second experiment examined more closely the role of amplitude modulations and intact phase information within the high-frequency region (4-8 kHz). CVCs were either natural or vocoded speech (both limited to a low-pass cutoff-frequency of 2.5 kHz) and were presented in stationary 3-kHz low-pass filtered masking noise. The experimental results did not support the hypothesized use of periodicity information for aiding low-frequency perception.

  12. Radio frequency system for nuclear fusion

    International Nuclear Information System (INIS)

    Kozeki, Shoichiro; Sagawa, Norimoto; Takizawa, Teruhiro

    1987-01-01

    The importance of radio frequency waves has been increasing in the area of nuclear fusion since they are indispensable for heating of plasma, etc. This report outlines radio frequency techniques used for nuclear fusion and describes the development of radio frequency systems (radio frequency plasma heating system and current drive system). Presently, in-depth studies are underway at various research institutes to achieve plasma heating by injection of radio frequency electric power. Three ranges of frequencies, ICRF (ion cyclotron range of frequency), LHRF (lower hybrid range of frequency) and ECRF (electron cyclotron range of frequency), are considered promissing for radio frequency heating. Candidate waves for plasma current driving include ECW (electron cyclotron wave), LHW (lower hybrid wave), MSW (magnetic sound wave), ICW (ion cyclotron wave) with minority component, and FW (fast wave). FW is the greatest in terms of current drive efficiency. In general, a radio frequency system for nuclear fusion consists of a radio frequency power source, transmission/matching circuit component and plasma connection component. (Nogami, K.)

  13. Stimulus specificity of a steady-state visual-evoked potential-based brain-computer interface

    Science.gov (United States)

    Ng, Kian B.; Bradley, Andrew P.; Cunnington, Ross

    2012-06-01

    The mechanisms of neural excitation and inhibition when given a visual stimulus are well studied. It has been established that changing stimulus specificity such as luminance contrast or spatial frequency can alter the neuronal activity and thus modulate the visual-evoked response. In this paper, we study the effect that stimulus specificity has on the classification performance of a steady-state visual-evoked potential-based brain-computer interface (SSVEP-BCI). For example, we investigate how closely two visual stimuli can be placed before they compete for neural representation in the cortex and thus influence BCI classification accuracy. We characterize stimulus specificity using the four stimulus parameters commonly encountered in SSVEP-BCI design: temporal frequency, spatial size, number of simultaneously displayed stimuli and their spatial proximity. By varying these quantities and measuring the SSVEP-BCI classification accuracy, we are able to determine the parameters that provide optimal performance. Our results show that superior SSVEP-BCI accuracy is attained when stimuli are placed spatially more than 5° apart, with size that subtends at least 2° of visual angle, when using a tagging frequency of between high alpha and beta band. These findings may assist in deciding the stimulus parameters for optimal SSVEP-BCI design.

  14. Frequency band adjustment match filtering based on variable frequency GPR antennas pairing scheme for shallow subsurface investigations

    Science.gov (United States)

    Shaikh, Shahid Ali; Tian, Gang; Shi, Zhanjie; Zhao, Wenke; Junejo, S. A.

    2018-02-01

    Ground penetrating Radar (GPR) is an efficient tool for subsurface geophysical investigations, particularly at shallow depths. The non-destructiveness, cost efficiency, and data reliability are the important factors that make it an ideal tool for the shallow subsurface investigations. Present study encompasses; variations in central frequency of transmitting and receiving GPR antennas (Tx-Rx) have been analyzed and frequency band adjustment match filters are fabricated and tested accordingly. Normally, the frequency of both the antennas remains similar to each other whereas in this study we have experimentally changed the frequencies of Tx-Rx and deduce the response. Instead of normally adopted three pairs, a total of nine Tx-Rx pairs were made from 50 MHz, 100 MHz, and 200 MHz antennas. The experimental data was acquired at the designated near surface geophysics test site of the Zhejiang University, Hangzhou, China. After the impulse response analysis of acquired data through conventional as well as varied Tx-Rx pairs, different swap effects were observed. The frequency band and exploration depth are influenced by transmitting frequencies rather than the receiving frequencies. The impact of receiving frequencies was noticed on the resolution; the more noises were observed using the combination of high frequency transmitting with respect to low frequency receiving. On the basis of above said variable results we have fabricated two frequency band adjustment match filters, the constant frequency transmitting (CFT) and the variable frequency transmitting (VFT) frequency band adjustment match filters. By the principle, the lower and higher frequency components were matched and then incorporated with intermediate one. Therefore, this study reveals that a Tx-Rx combination of low frequency transmitting with high frequency receiving is a better choice. Moreover, both the filters provide better radargram than raw one, the result of VFT frequency band adjustment filter is

  15. Low-frequency hippocampal-cortical activity drives brain-wide resting-state functional MRI connectivity.

    Science.gov (United States)

    Chan, Russell W; Leong, Alex T L; Ho, Leon C; Gao, Patrick P; Wong, Eddie C; Dong, Celia M; Wang, Xunda; He, Jufang; Chan, Ying-Shing; Lim, Lee Wei; Wu, Ed X

    2017-08-15

    The hippocampus, including the dorsal dentate gyrus (dDG), and cortex engage in bidirectional communication. We propose that low-frequency activity in hippocampal-cortical pathways contributes to brain-wide resting-state connectivity to integrate sensory information. Using optogenetic stimulation and brain-wide fMRI and resting-state fMRI (rsfMRI), we determined the large-scale effects of spatiotemporal-specific downstream propagation of hippocampal activity. Low-frequency (1 Hz), but not high-frequency (40 Hz), stimulation of dDG excitatory neurons evoked robust cortical and subcortical brain-wide fMRI responses. More importantly, it enhanced interhemispheric rsfMRI connectivity in various cortices and hippocampus. Subsequent local field potential recordings revealed an increase in slow oscillations in dorsal hippocampus and visual cortex, interhemispheric visual cortical connectivity, and hippocampal-cortical connectivity. Meanwhile, pharmacological inactivation of dDG neurons decreased interhemispheric rsfMRI connectivity. Functionally, visually evoked fMRI responses in visual regions also increased during and after low-frequency dDG stimulation. Together, our results indicate that low-frequency activity robustly propagates in the dorsal hippocampal-cortical pathway, drives interhemispheric cortical rsfMRI connectivity, and mediates visual processing.

  16. Automatic oscillator frequency control system

    Science.gov (United States)

    Smith, S. F. (Inventor)

    1985-01-01

    A frequency control system makes an initial correction of the frequency of its own timing circuit after comparison against a frequency of known accuracy and then sequentially checks and corrects the frequencies of several voltage controlled local oscillator circuits. The timing circuit initiates the machine cycles of a central processing unit which applies a frequency index to an input register in a modulo-sum frequency divider stage and enables a multiplexer to clock an accumulator register in the divider stage with a cyclical signal derived from the oscillator circuit being checked. Upon expiration of the interval, the processing unit compares the remainder held as the contents of the accumulator against a stored zero error constant and applies an appropriate correction word to a correction stage to shift the frequency of the oscillator being checked. A signal from the accumulator register may be used to drive a phase plane ROM and, with periodic shifts in the applied frequency index, to provide frequency shift keying of the resultant output signal. Interposition of a phase adder between the accumulator register and phase plane ROM permits phase shift keying of the output signal by periodic variation in the value of a phase index applied to one input of the phase adder.

  17. Chimera Type Behavior in Nonlocal Coupling System with Two Different Inherent Frequencies

    Science.gov (United States)

    Lin, Larry; Li, Ping-Cheng; Tseng, Hseng-Che

    2014-03-01

    From the research of Kuramoto and Strogatz, arrays of identical oscillators can display a remarkable pattern, named chimera state, in which phase-locked oscillators coexist with drifting ones in nonlocal coupling oscillator system. We consider further in this study, two groups of oscillators with different inherent frequencies and arrange them in a ring. When the difference of the inherent frequencies is within some specific parameter range, oscillators of nonlocal coupling system show two distinct chimera states. When the parameter value exceeds some threshold value, two chimera states disappear. They show different features. The statistical dynamic behavior of the system can be described by Kuramoto theory.

  18. Probing a molecular electronic transition by two-colour sum-frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Humbert, C.; Dreesen, L.; Nihonyanagi, S.; Masuda, T.; Kondo, T.; Mani, A.A.; Uosaki, K.; Thiry, P.A.; Peremans, A.

    2003-01-01

    We demonstrate that a new emerging technique, two-colour sum-frequency generation (SFG) spectroscopy, can be used to probe the molecular electronic properties of self-assembled monolayers (SAMs). In the CH spectral range (2800-3200 cm -1 ), we show that the sum-frequency generation signal of a porphyrin alkanethiol derivative adsorbed on Pt(1 1 1) reaches a maximum intensity at ∼435 nm SFG wavelength. This wavelength corresponds to the porphyrin moiety specific π-π* molecular electronic transition which is called the Soret or B band. This resonant behaviour is not observed for 1-dodecanethiol SAMs, which are devoid of molecular electronic transition in the investigated visible spectral range

  19. Meal frequencies in early adolescence predict meal frequencies in late adolescence and early adulthood

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Flachs, Esben Meulengracht

    2013-01-01

    Health and risk behaviours tend to be maintained from adolescence into adulthood. There is little knowledge on whether meal frequencies in adolescence are maintained into adulthood. We investigated whether breakfast, lunch and evening meal frequencies in early adolescence predicted meal frequencies...

  20. Optical Frequency Mixing in Periodically-Patterned and in Quasi-Periodically-Patterned Nonlinear media

    International Nuclear Information System (INIS)

    Arie, A.

    1999-01-01

    Nonlinear frequency mixing processes, e.g. second harmonic generation, sum and difference frequency generation, etc., require matching of the phases of the interacting waves. The traditional method to achieve it is by selecting a specific angle of propagation in a birefringent nonlinear crystal. The main limitation of the birefringent phase matching method stems from the fact that for many interesting interactions, the phase matching condition cannot be satisfied in a specific crystal. This obstacle can be removed by the technique of quasi-phase-matching (QPM), where the nonlinear coefficient of the material is modulated at a fixed spatial frequency that equals the wave-vector phase mismatch between the interacting waves. An important development in recent years is the ability to periodically reverse the sign of the nonlinear coefficient in ferroelectric crystals by applying a high electric field through a periodic electrode. Some recent QPM interactions in periodically-poled KTP that were recently achieved at Tel-Aviv University include continuous-wave optical parametric oscillations, as well as generation of tunable mid-infrared radiation by difference frequency generation. Periodic patterning of the nonlinear coefficient enables to phase match only a single interaction. It would be advantageous to further extend the applications of this technique in order to simultaneously satisfy several interactions on a single crystal. This cannot be usually achieved in a periodic pattern, however more sophisticated quasi-periodic structures can be designed in this case. An interesting analogy can be drawn between artificially-made quasi-periodically-patterned nonlinear crystals and quasi-crystals found in nature, in rapidly-cooled metallic alloys

  1. Low Frequency Space Array

    International Nuclear Information System (INIS)

    Dennison, B.; Weiler, K.W.; Johnston, K.J.

    1987-01-01

    The Low Frequency Space Array (LFSA) is a conceptual mission to survey the entire sky and to image individual sources at frequencies between 1.5 and 26 MHz, a frequency range over which the earth's ionosphere transmits poorly or not at all. With high resolution, high sensitivity observations, a new window will be opened in the electromagnetic spectrum for astronomical investigation. Also, extending observations down to such low frequencies will bring astronomy to the fundamental limit below which the galaxy becomes optically thick due to free-free absorption. A number of major scientific goals can be pursued with such a mission, including mapping galactic emission and absorption, studies of individual source spectra in a frequency range where a number of important processes may play a role, high resolution imaging of extended sources, localization of the impulsive emission from Jupiter, and a search for coherent emission processes. 19 references

  2. Calibration of ultra-high frequency (UHF) partial discharge sensors using FDTD method

    Science.gov (United States)

    Ishak, Asnor Mazuan; Ishak, Mohd Taufiq

    2018-02-01

    Ultra-high frequency (UHF) partial discharge sensors are widely used for conditioning monitoring and defect location in insulation system of high voltage equipment. Designing sensors for specific applications often requires an iterative process of manufacturing, testing and mechanical modifications. This paper demonstrates the use of finite-difference time-domain (FDTD) technique as a tool to predict the frequency response of UHF PD sensors. Using this approach, the design process can be simplified and parametric studies can be conducted in order to assess the influence of component dimensions and material properties on the sensor response. The modelling approach is validated using gigahertz transverse electromagnetic (GTEM) calibration system. The use of a transient excitation source is particularly suitable for modeling using FDTD, which is able to simulate the step response output voltage of the sensor from which the frequency response is obtained using the same post-processing applied to the physical measurement.

  3. On the Link Between Benevolent Sexism and Orgasm Frequency in Heterosexual Women.

    Science.gov (United States)

    Harris, Emily Ann; Hornsey, Matthew J; Barlow, Fiona Kate

    2016-11-01

    Previous research on subclinical orgasmic difficulties among women has focused on intrapsychic and interpersonal variables, but little attention has been paid to the more distal ideological factors that might indirectly constrain sexual pleasure. We hypothesized that women's endorsement of a benevolently sexist worldview would be negatively associated with orgasm frequency. Specifically, we predicted that benevolent sexism would be associated with increased perceptions of male sexual selfishness. This perception of men as interested in their own sexual pleasure would then predict decreased willingness to ask a partner for sexual pleasure, which in turn would be associated with less frequent orgasms. We found support for our model across two studies (Study 1: N = 339; Study 2: N = 323). We did not, however, find a direct effect of benevolent sexism on orgasm frequency. We discuss possible additional variables linking benevolent sexism with orgasm frequency, implications, and future directions.

  4. Frequency-Specific Abnormalities of Intrinsic Functional Connectivity Strength among Patients with Amyotrophic Lateral Sclerosis: A Resting-State fMRI Study.

    Science.gov (United States)

    Li, Fangjun; Zhou, Fuqing; Huang, Muhua; Gong, Honghan; Xu, Renshi

    2017-01-01

    The classical concept that amyotrophic lateral sclerosis (ALS) is a degenerative disorder characterized by the loss of upper and lower motor neurons is agreed. However, more and more studies have suggested the involvement of some extra-motor regions. The aim of this study is to investigate the frequency-related alteration pattern of intrinsic functional connectivity strength (FCS) at the voxel-wise level in the relatively early-stage of ALS on a whole brain scale. In this study, 21 patients with ALS and 21 well-matched healthy control subjects were enrolled to examine the intrinsic FCS in the different frequencies (slow-4: 0.027-0.073 Hz; slow-5: 0.01-0.027 Hz, and typical band: 0.01-0.1 Hz). Compared with the control subjects, the ALS patients showed a significantly decreased FCS in the left prefrontal cortex (PFC) and the bilateral superior frontal gyrus. In the slow-5 band, the patients with ALS showed decreased FCS in the left lingual gyrus, as well as increased FCS in the left postcentral gyrus/paracentral lobule (PoCG/PARC). In the slow-4 band, the ALS patients presented decreased FCS in the left and right ventrolateral PFC. Moreover, the increased FCS in the left PoCG/PARC in the slow-5 band was positively correlated with the ALSFRS-r score ( P = 0.015). Our results demonstrated that the FCS changes in ALS were wide spread and frequency dependent. These findings may provide some evidences that ALS patients have the consistent impairment in some extra-motor regions at a relatively early-stage.

  5. Auditory filters at low-frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Møller, Henrik

    2009-01-01

    -ear transfer function), the asymmetry of the auditory filter changed from steeper high-frequency slopes at 1000 Hz to steeper low-frequency slopes below 100 Hz. Increasing steepness at low-frequencies of the middle-ear high-pass filter is thought to cause this effect. The dynamic range of the auditory filter...... was found to steadily decrease with decreasing center frequency. Although the observed decrease in filter bandwidth with decreasing center frequency was only approximately monotonic, the preliminary data indicates the filter bandwidth does not stabilize around 100 Hz, e.g. it still decreases below...

  6. Increased frequency of HLA-DPw2 in pauciarticular onset juvenile chronic arthritis

    DEFF Research Database (Denmark)

    Ødum, Niels; Morling, Niels; Friis, J

    1986-01-01

    Thirty-six unrelated Danish patients with pauciarticular Juvenile Chronic Arthritis (PJCA) and 120 controls were typed for HLA-DPw1-w6 and the local specificity CDPHEI with bulk-expanded Primed Lymphocyte Typing (PLT) cells. The frequency of HLA-DPw2 was 52.8% in PJCA patients and 16.7% in controls...

  7. Increased frequency of HLA-DPw2 in pauciarticular onset juvenile chronic arthritis

    DEFF Research Database (Denmark)

    Ødum, Niels; Morling, Niels; Friis, J

    1986-01-01

    Thirty-six unrelated Danish patients with pauciarticular Juvenile Chronic Arthritis (PJCA) and 120 controls were typed for HLA-DPw1-w6 and the local specificity CDPHEI with bulk-expanded Primed Lymphocyte Typing (PLT) cells. The frequency of HLA-DPw2 was 52.8% in PJCA patients and 16.7% in contro...

  8. Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head.

    Science.gov (United States)

    Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Rasouli Amirhajeloo, Leila; Mirzaei, Maryam

    2016-09-01

    The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m  and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart  mobile phones at the frequencies of 900 and 1800 MHz  was significantly higher than Samsung (p value Samsung smart mobile phone.

  9. Low velocity target detection based on time-frequency image for high frequency ground wave radar

    Institute of Scientific and Technical Information of China (English)

    YAN Songhua; WU Shicai; WEN Biyang

    2007-01-01

    The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave(HEGW)radar.By displaying the change of signal energy on two dimensional time-frequency images based on time-frequency analysis,a new mathematical morphology method to distinguish target from nonlinear time-frequency curves is presented.The analyzed results from the measured data verify that with this new method the target can be detected correctly from wide Doppler spectrum.

  10. Specialization of the auditory system for the processing of bio-sonar information in the frequency domain: Mustached bats.

    Science.gov (United States)

    Suga, Nobuo

    2018-04-01

    For echolocation, mustached bats emit velocity-sensitive orientation sounds (pulses) containing a constant-frequency component consisting of four harmonics (CF 1-4 ). They show unique behavior called Doppler-shift compensation for Doppler-shifted echoes and hunting behavior for frequency and amplitude modulated echoes from fluttering insects. Their peripheral auditory system is highly specialized for fine frequency analysis of CF 2 (∼61.0 kHz) and detecting echo CF 2 from fluttering insects. In their central auditory system, lateral inhibition occurring at multiple levels sharpens V-shaped frequency-tuning curves at the periphery and creates sharp spindle-shaped tuning curves and amplitude tuning. The large CF 2 -tuned area of the auditory cortex systematically represents the frequency and amplitude of CF 2 in a frequency-versus-amplitude map. "CF/CF" neurons are tuned to a specific combination of pulse CF 1 and Doppler-shifted echo CF 2 or 3 . They are tuned to specific velocities. CF/CF neurons cluster in the CC ("C" stands for CF) and DIF (dorsal intrafossa) areas of the auditory cortex. The CC area has the velocity map for Doppler imaging. The DIF area is particularly for Dopper imaging of other bats approaching in cruising flight. To optimize the processing of behaviorally relevant sounds, cortico-cortical interactions and corticofugal feedback modulate the frequency tuning of cortical and sub-cortical auditory neurons and cochlear hair cells through a neural net consisting of positive feedback associated with lateral inhibition. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Frequency of skin reactivity to food allergens in allergic patients

    Directory of Open Access Journals (Sweden)

    Heriberto Camero-Martínez

    2017-10-01

    Full Text Available Background: Food allergy is deemed to have a worldwide prevalence ranging from 2 to 10 %. Objective: To determine the frequency of skin reactivity to food allergens by age groups. Methods: Cross-sectional, descriptive, prolective, observational study. Patients aged from 2 to 64 years with symptoms consistent with allergic disease were included. Skin prick tests were carried out with food allergens. Frequencies and percentages were estimated. Results: One-hundred and ninety-one patients were included, out of which 63.4% were females. Mean age was 22.5 years; 19.3 % showed positive skin reactivity to at least one food. Distribution by age group was as follows: preschool children 13.5 %, schoolchildren 24.3 %, adolescents 2.7 % and adults 59.5 %. Diagnoses included allergic rhinitis in 84.3 %, asthma in 19.4 %, urticaria in 14.1 % and atopic dermatitis in 8.4 %. Positive skin reactivity frequency distribution in descending order was: soybeans with 5.2 %, peach with 4.7 %, grapes, orange and apple with 3.6 %, nuts with 3.1 %, pineapple, avocado, tomato and tuna with 2.6 %. Conclusion: The frequency of skin reactivity to food allergens was similar to that reported in the national and Latin American literature, but sensitization to each specific allergen varied for each age group.

  12. Tip-of-the-tongue states reveal age differences in the syllable frequency effect.

    Science.gov (United States)

    Farrell, Meagan T; Abrams, Lise

    2011-01-01

    Syllable frequency has been shown to facilitate production in some languages but has yielded inconsistent results in English and has never been examined in older adults. Tip-of-the-tongue (TOT) states represent a unique type of production failure where the phonology of a word is unable to be retrieved, suggesting that the frequency of phonological forms, like syllables, may influence the occurrence of TOT states. In the current study, we investigated the role of first-syllable frequency on TOT incidence and resolution in young (18-26 years of age), young-old (60-74 years of age), and old-old (75-89 years of age) adults. Data from 3 published studies were compiled, where TOTs were elicited by presenting definition-like questions and asking participants to respond with "Know," "Don't Know," or "TOT." Young-old and old-old adults, but not young adults, experienced more TOTs for words beginning with low-frequency first syllables relative to high-frequency first syllables. Furthermore, age differences in TOT incidence occurred only for words with low-frequency first syllables. In contrast, when a prime word with the same first syllable as the target was presented during TOT states, all age groups resolved more TOTs for words beginning with low-frequency syllables. These findings support speech production models that allow for bidirectional activation between conceptual, lexical, and phonological forms of words. Furthermore, the age-specific effects of syllable frequency provide insight into the progression of age-linked changes to phonological processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  13. Observed Hierarchy of Student Proficiency with Period, Frequency, and Angular Frequency

    Science.gov (United States)

    Young, Nicholas T.; Heckler, Andrew F.

    2018-01-01

    In the context of a generic harmonic oscillator, we investigated students' accuracy in determining the period, frequency, and angular frequency from mathematical and graphical representations. In a series of studies including interviews, free response tests, and multiple-choice tests developed in an iterative process, we assessed students in both…

  14. The impact of stimulus complexity and frequency swapping on stabilization of binocular rivalry

    DEFF Research Database (Denmark)

    Sandberg, Kristian; Bahrami, B; Lindeløv, Jonas Kristoffer

    2011-01-01

    high-level perceptual content. We conclude that overlaps at low visual stages are the most likely cause of the eye-specific stabilization for both stimulus types. Additionally, we examined the impact of swapping the flicker frequency of the images and found a general impact on stabilization...

  15. Frequency-Dependent Altered Functional Connections of Default Mode Network in Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Youjun Li

    2017-08-01

    Full Text Available Alzheimer’s disease (AD is a neurodegenerative disorder associated with the progressive dysfunction of cognitive ability. Previous research has indicated that the default mode network (DMN is closely related to cognition and is impaired in Alzheimer’s disease. Because recent studies have shown that different frequency bands represent specific physiological functions, DMN functional connectivity studies of the different frequency bands based on resting state fMRI (RS-fMRI data may provide new insight into AD pathophysiology. In this study, we explored the functional connectivity based on well-defined DMN regions of interest (ROIs from the five frequency bands: slow-5 (0.01–0.027 Hz, slow-4 (0.027–0.073 Hz, slow-3 (0.073–0.198 Hz, slow-2 (0.198–0.25 Hzs and standard low-frequency oscillations (LFO (0.01–0.08 Hz. We found that the altered functional connectivity patterns are mainly in the frequency band of slow-5 and slow-4 and that the decreased connections are long distance, but some relatively short connections are increased. In addition, the altered functional connections of the DMN in AD are frequency dependent and differ between the slow-5 and slow-4 bands. Mini-Mental State Examination scores were significantly correlated with the altered functional connectivity patterns in the slow-5 and slow-4 bands. These results indicate that frequency-dependent functional connectivity changes might provide potential biomarkers for AD pathophysiology.

  16. High frequency breakdown voltage

    International Nuclear Information System (INIS)

    Chu, Thanh Duy.

    1992-03-01

    This report contains information about the effect of frequency on the breakdown voltage of an air gap at standard pressure and temperature, 76 mm Hg and O degrees C, respectively. The frequencies of interest are 47 MHz and 60 MHz. Additionally, the breakdown in vacuum is briefly considered. The breakdown mechanism is explained on the basis of collision and ionization. The presence of the positive ions produced by ionization enhances the field in the gap, and thus determines the breakdown. When a low-frequency voltage is applied across the gap, the breakdown mechanism is the same as that caused by the DC or static voltage. However, when the frequency exceeds the first critical value f c , the positive ions are trapped in the gap, increasing the field considerably. This makes the breakdown occur earlier; in other words, the breakdown voltage is lowered. As the frequency increases two decades or more, the second critical frequency, f ce , is reached. This time the electrons start being trapped in the gap. Those electrons that travel multiple times across the gap before reaching the positive electrode result in an enormous number of electrons and positive ions being present in the gap. The result is a further decrease of the breakdown voltage. However, increasing the frequency does not decrease the breakdown voltage correspondingly. In fact, the associated breakdown field intensity is almost constant (about 29 kV/cm).The reason is that the recombination rate increases and counterbalances the production rate, thus reducing the effect of the positive ions' concentration in the gap. The theory of collision and ionization does not apply to the breakdown in vacuum. It seems that the breakdown in vacuum is primarily determined by the irregularities on the surfaces of the electrodes. Therefore, the effect of frequency on the breakdown, if any, is of secondary importance

  17. Direct excitation of a high frequency wave by a low frequency wave in a plasma

    International Nuclear Information System (INIS)

    Tanaka, Takayasu

    1993-01-01

    A new mechanism is presented of an excitation of a high frequency wave by a low frequency wave in a plasma. This mechanism works when the low frequency wave varies in time in a manner deviated from a usual periodic motion with a constant amplitude. The conversion rate is usually not large but the conversion is done without time delay after the variation of the low frequency wave. The Manley Rowe relation in the usual sense does not hold in this mechanism. This mechanism can excite also waves with same or lower frequencies. (author)

  18. Energy harvesting with self-sufficient frequency-tunable piezoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Eichhorn, Christoph

    2011-07-01

    In this dissertation, a piezoelectric energy harvester is presented, which is able to extract electric energy from weak ambient vibrations. This can be useful e.g. to run a wireless sensor node in order to make such a sensor independent of batteries. Without the requirement of batteries, the maintenance costs of large sensor networks could be lowered and the environmental pollution due to batteries can be reduced. Mechanical vibrations represent one out of different ambient energy sources for energy harvesting. To exploit vibrations with small amplitudes, it is essential to use the resonance amplification of a harmonic oscillator with a high quality factor. The mechanical energy of such a resonant oscillator can then be transformed into electrical energy. The advantage of the resonance amplification is however lost if this natural frequency does not match exactly the frequency of the ambient vibration. This constraint represents one of the most serious obstacles in vibration energy harvesting applications. What makes the generator presented in this work special is its ability to dynamically readjust its natural frequency in an energy-autonomous way. With this feature, it can prevent frequency mismatches and can therefore generate electrical power in an efficient way, even in environments which provide vibrations with non-constant frequencies. This can be the case e.g. on machines that contain rotors with a variable number of revolutions per minute. An example for such an environment is an automobile, where the generated vibrations are usually correlated to the cruising speed. Adaptive systems are however not only useful to face variable vibration frequencies. Many environments offer constant but very specific vibration frequencies. Adaptive energy harvesters allow vibrations with individual properties to be exploited without expensive customized solutions. Due to their adaptability, such generators can be driven within a certain frequency range, which allows to

  19. Task Specific Inter-Hemispheric Coupling in Human Subthalamic Nuclei

    Directory of Open Access Journals (Sweden)

    Felix eDarvas

    2014-09-01

    Full Text Available Cortical networks and quantitative measures of connectivity are integral to the study of brain function. Despite lack of direct connections between left and right subthalamic nuclei (STN, there are apparent physiological connections. During clinical examination of patients with Parkinson’s Disease (PD, this connectivity is exploited to enhance signs of PD, yet our understanding of this connectivity is limited. We hypothesized that movement leads to synchronization of neural oscillations in bilateral STN, and we implemented phase coherence, a measure of phase-locking between cortical sites in a narrow frequency band, to demonstrate this synchronization. We analyzed task specific phase synchronization and causality between left and right STN local field potentials (LFP recorded from both hemispheres simultaneously during a cued movement task in four subjects with PD who underwent Deep Brain Stimulation (DBS surgery. We used a data driven approach to determine inter-hemispheric channel pairs and frequencies with a task specific increase in phase locking.We found significant phase locking between hemispheres in alpha frequency (8-12 Hz in all subjects concurrent with movement of either hand. In all subjects, phase synchronization increased over baseline upon or prior to hand movement onset and lasted until the motion ceased. Left and right hand movement showed similar patterns. Granger causality at the phase-locking frequencies between synchronized electrodes revealed a unidirectional causality from right to left STN regardless of which side was moved.Phase synchronization across hemispheres between basal ganglia supports existence of a bilateral network having lateralized regions of specialization for motor processing. Our results suggest this bilateral network is activated by a unilateral motor program. Understanding phase synchronization in natural brain functions is critical to development of future DBS systems that augment goal directed

  20. Measurement of Line-to-Ground Capacitance in Distribution Network Considering Magnetizing Impedance’s Frequency Characteristic

    Directory of Open Access Journals (Sweden)

    Qing Yang

    2017-04-01

    Full Text Available Signal injection method (SIM is widely applied to the insulation parameters’ measurement in distribution network for its convenience and safety. It can be divided into two kinds of patterns: injecting a specific frequency signal or several frequencies’ groups, and scanning frequency in a scheduled frequency scope. In order to avoid the disadvantages in related researches, improved signal injection method (ISIM, in which the frequency characteristic of the transformer magnetizing impedance is taken into consideration, is proposed. In addition, optimization for signal injection position has been accomplished, and the corresponding three calculation methods of line-to-ground capacitance has been derived. Calculations are carried out through the vector information (vector calculation method, the amplitude information (amplitude calculation method, the phase information (phase calculation method of voltage and current in signal injecting port, respectively. The line-to-ground capacitance is represented by lumped parameter capacitances in high-voltage simulation test. Eight different sinusoidal signals are injected into zero-sequence circuit, and then line-to-ground capacitance is calculated with the above-mentioned vector calculation method based on the voltage and the current data of the injecting port. The results obtained by the vector calculation method show that ISIM has a wider application frequency range compared with signal injection method with rated parameters (RSIM and SIM. The RSIM is calculated with the rated transformer parameters of magnetizing impedance, and the SIM based on the ideal transformer model, and the relative errors of calculation results of ISIM are smaller than that for other methods in general. The six groups of two-frequency set are chosen in a specific scope which is recommended by vector calculation results. Based on ISIM, the line-to-ground capacitance calculations through the amplitude calculation method and

  1. ALMA High Frequency Techniques

    Science.gov (United States)

    Meyer, J. D.; Mason, B.; Impellizzeri, V.; Kameno, S.; Fomalont, E.; Chibueze, J.; Takahashi, S.; Remijan, A.; Wilson, C.; ALMA Science Team

    2015-12-01

    The purpose of the ALMA High Frequency Campaign is to improve the quality and efficiency of science observing in Bands 8, 9, and 10 (385-950 GHz), the highest frequencies available to the ALMA project. To this end, we outline observing modes which we have demonstrated to improve high frequency calibration for the 12m array and the ACA, and we present the calibration of the total power antennas at these frequencies. Band-to-band (B2B) transfer and bandwidth switching (BWSW), techniques which improve the speed and accuracy of calibration at the highest frequencies, are most necessary in Bands 8, 9, and 10 due to the rarity of strong calibrators. These techniques successfully enable increased signal-to-noise on the calibrator sources (and better calibration solutions) by measuring the calibrators at lower frequencies (B2B) or in wider bandwidths (BWSW) compared to the science target. We have also demonstrated the stability of the bandpass shape to better than 2.4% for 1 hour, hidden behind random noise, in Band 9. Finally, total power observing using the dual sideband receivers in Bands 9 and 10 requires the separation of the two sidebands; this procedure has been demonstrated in Band 9 and is undergoing further testing in Band 10.

  2. Experiments and characterization of low-frequency oscillations in a granular column

    Science.gov (United States)

    Oyarte Gálvez, Loreto; Rivas, Nicolás; van der Meer, Devaraj

    2018-04-01

    The behavior of a vertically vibrated granular bed is reminiscent of a liquid in that it exhibits many phenomena such as convection and Faraday-like surface waves. However, when the lateral dimensions of the bed are confined such that a quasi-one-dimensional geometry is formed, the only phenomena that remain are bouncing bed and the granular Leidenfrost effect. This permits the observation of the granular Leidenfrost state for a wide range of energy injection parameters and more specifically allows for a thorough characterization of the low-frequency oscillation (LFO) that is present in this state. In both experiments and particle simulations we determine the LFO frequency from the power spectral density of the center-of-mass signal of the grains, varying the amplitude and frequency of the driving, the particle diameter, and the number of layers in the system. We thus find that the LFO frequency (i) is inversely proportional to the fast inertial timescale and (ii) decorrelates with a typical decay time proportional to the slow dissipative timescale in the system. The latter is consistent with the view that the LFO is driven by the inherent noise that is present in the granular Leidenfrost state with a low number of particles.

  3. Secured Communication over Frequency-Selective Fading Channels: A Practical Vandermonde Precoding

    Directory of Open Access Journals (Sweden)

    Debbah Mérouane

    2009-01-01

    Full Text Available We study the frequency-selective broadcast channel with confidential messages (BCC where the transmitter sends a confidential message to receiver 1 and a common message to receivers 1 and 2. In the case of a block transmission of symbols followed by a guard interval of symbols, the frequency-selective channel can be modeled as a Toeplitz matrix. For this special type of multiple-input multiple-output channels, we propose a practical Vandermonde precoding that projects the confidential messages in the null space of the channel seen by receiver 2 while superposing the common message. For this scheme, we provide the achievable rate region and characterize the optimal covariance for some special cases of interest. Interestingly, the proposed scheme can be applied to other multiuser scenarios such as the -user frequency-selective BCC with confidential messages and the two-user frequency-selective BCC with two confidential messages. For each scenario, we provide the secrecy degree of freedom (s.d.o.f. region of the corresponding channel and prove the optimality of the Vandermonde precoding. One of the appealing features of the proposed scheme is that it does not require any specific secrecy encoding technique but can be applied on top of any existing powerful encoding schemes.

  4. Evaluation of medial patellofemoral ligament tears after acute lateral patellar dislocation: comparison of high-frequency ultrasound and MR

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guang-Ying; Ding, Hong-Yu [Shandong University, Department of Ultrasonography, Qianfoshan Hospital, Jinan (China); Zheng, Lei; Sun, Bai-Sheng [Chinese People' s Armed Police Force, Department of Radiology, Shandong Provincial Corps Hospital, Jinan (China); Li, En-Miao [Jinan Third People' s Hospital, Department of Ultrasonography, Jinan (China); Shi, Hao [Shandong University, Department of Radiology, Qianfoshan Hospital, Jinan (China)

    2015-01-15

    The purpose of this study was to compare the diagnostic performance of high-frequency ultrasound with MR in the evaluation of medial patellofemoral ligament (MPFL) lesions after acute lateral patellar dislocation (LPD). High-frequency ultrasound and MR images were prospectively obtained in 97 consecutive patients with acute LPD. Images were acquired using standardised protocols and were independently evaluated by two radiologists. The MPFL was assessed at three sites (patellar insertion, femoral attachment, and mid-substance) for signs of injury. Of a total of 291 sites in 97 MPFLs, 127 showed proven MPFL tear at surgery, including 51 sites of complete tear and 76 sites of partial tear. In a site-based analysis, the sensitivity, specificity, and accuracy of high-frequency ultrasound was 90.8 %, 96.3 %, and 94.6 %, respectively, for partial MPFL tear and 86.3 %, 96.3 %, and 94 %, respectively, for complete tear. For MR, the sensitivity, specificity, and accuracy was 81.6 %, 95.7 %, and 91.3 %, respectively, for partial MPFL tear and 80.4 %, 95.7 %, and 92.1 %, respectively, for complete tear. There was no statistical difference between high-frequency ultrasound and MR in the assessment of partial (P = 0.1, 0.777, 0.155) or complete (P = 0.425, 0.777, 0.449) MPFL lesions. Interobserver agreement was very good for high-frequency ultrasound and good for MR. Data suggest that high-frequency ultrasound and MR have similar diagnostic performance in the evaluation of MPFL lesions after acute LPD. (orig.)

  5. Evaluation of medial patellofemoral ligament tears after acute lateral patellar dislocation: comparison of high-frequency ultrasound and MR

    International Nuclear Information System (INIS)

    Zhang, Guang-Ying; Ding, Hong-Yu; Zheng, Lei; Sun, Bai-Sheng; Li, En-Miao; Shi, Hao

    2015-01-01

    The purpose of this study was to compare the diagnostic performance of high-frequency ultrasound with MR in the evaluation of medial patellofemoral ligament (MPFL) lesions after acute lateral patellar dislocation (LPD). High-frequency ultrasound and MR images were prospectively obtained in 97 consecutive patients with acute LPD. Images were acquired using standardised protocols and were independently evaluated by two radiologists. The MPFL was assessed at three sites (patellar insertion, femoral attachment, and mid-substance) for signs of injury. Of a total of 291 sites in 97 MPFLs, 127 showed proven MPFL tear at surgery, including 51 sites of complete tear and 76 sites of partial tear. In a site-based analysis, the sensitivity, specificity, and accuracy of high-frequency ultrasound was 90.8 %, 96.3 %, and 94.6 %, respectively, for partial MPFL tear and 86.3 %, 96.3 %, and 94 %, respectively, for complete tear. For MR, the sensitivity, specificity, and accuracy was 81.6 %, 95.7 %, and 91.3 %, respectively, for partial MPFL tear and 80.4 %, 95.7 %, and 92.1 %, respectively, for complete tear. There was no statistical difference between high-frequency ultrasound and MR in the assessment of partial (P = 0.1, 0.777, 0.155) or complete (P = 0.425, 0.777, 0.449) MPFL lesions. Interobserver agreement was very good for high-frequency ultrasound and good for MR. Data suggest that high-frequency ultrasound and MR have similar diagnostic performance in the evaluation of MPFL lesions after acute LPD. (orig.)

  6. Modeling hemoglobin at optical frequency using the unconditionally stable fundamental ADI-FDTD method.

    Science.gov (United States)

    Heh, Ding Yu; Tan, Eng Leong

    2011-04-12

    This paper presents the modeling of hemoglobin at optical frequency (250 nm - 1000 nm) using the unconditionally stable fundamental alternating-direction-implicit finite-difference time-domain (FADI-FDTD) method. An accurate model based on complex conjugate pole-residue pairs is proposed to model the complex permittivity of hemoglobin at optical frequency. Two hemoglobin concentrations at 15 g/dL and 33 g/dL are considered. The model is then incorporated into the FADI-FDTD method for solving electromagnetic problems involving interaction of light with hemoglobin. The computation of transmission and reflection coefficients of a half space hemoglobin medium using the FADI-FDTD validates the accuracy of our model and method. The specific absorption rate (SAR) distribution of human capillary at optical frequency is also shown. While maintaining accuracy, the unconditionally stable FADI-FDTD method exhibits high efficiency in modeling hemoglobin.

  7. Direct current contamination of kilohertz frequency alternating current waveforms.

    Science.gov (United States)

    Franke, Manfred; Bhadra, Niloy; Bhadra, Narendra; Kilgore, Kevin

    2014-07-30

    Kilohertz frequency alternating current (KHFAC) waveforms are being evaluated in a variety of physiological settings because of their potential to modulate neural activity uniquely when compared to frequencies in the sub-kilohertz range. However, the use of waveforms in this frequency range presents some unique challenges regarding the generator output. In this study we explored the possibility of undesirable contamination of the KHFAC waveforms by direct current (DC). We evaluated current- and voltage-controlled KHFAC waveform generators in configurations that included a capacitive coupling between generator and electrode, a resistive coupling and combinations of capacitive with inductive coupling. Our results demonstrate that both voltage- and current-controlled signal generators can unintentionally add DC-contamination to a KHFAC signal, and that capacitive coupling is not always sufficient to eliminate this contamination. We furthermore demonstrated that high value inductors, placed in parallel with the electrode, can be effective in eliminating DC-contamination irrespective of the type of stimulator, reducing the DC contamination to less than 1 μA. This study highlights the importance of carefully designing the electronic setup used in KHFAC studies and suggests specific testing that should be performed and reported in all studies that assess the neural response to KHFAC waveforms. Published by Elsevier B.V.

  8. Impact of Sterile Compounding Batch Frequency on Pharmaceutical Waste.

    Science.gov (United States)

    Abbasi, Ghalib; Gay, Evan

    2017-01-01

    Purpose: To measure the impact of increasing sterile compounding batch frequency on pharmaceutical waste as it relates to cost and quantity. Methods: Pharmaceutical IV waste at a tertiary care hospital was observed and recorded for 7 days. The batching frequency of compounded sterile products (CSPs) was then increased from twice daily to 4 times daily. After a washout period, pharmaceutical IV waste was then recorded for another 7 days. The quantity of units wasted and the cost were compared between both phases to determine the impact that batching frequency has on IV waste, specifically among high- and low-cost drugs. Results: Patient days increased from 2,459 during phase 1 to 2,617 during phase 2. The total number of CSPs wasted decreased from 3.6 to 2.7 doses per 100 patient days. Overall cost was reduced from $4,585.36 in phase 1 to $4,453.88 in phase 2. The value of wasted high-cost drugs per 100 patient days increased from $146 in phase 1 to $149 in phase 2 ( p > .05). The value of wasted low cost drugs per 100 patient days decreased from $41 in phase 1 to $21 in phase 2 ( p waste quantity and cost. The highest impact of the intervention was observed among low-cost CSPs.

  9. Frequency-agile dual-comb spectroscopy

    OpenAIRE

    Millot, Guy; Pitois, Stéphane; Yan, Ming; Hovannysyan, Tatevik; Bendahmane, Abdelkrim; Hänsch, Theodor W.; Picqué, Nathalie

    2015-01-01

    We propose a new approach to near-infrared molecular spectroscopy, harnessing advanced concepts of optical telecommunications and supercontinuum photonics. We generate, without mode-locked lasers, two frequency combs of slightly different repetition frequencies and moderate, but rapidly tunable, spectral span. The output of a frequency-agile continuous wave laser is split and sent into two electro-optic intensity modulators. Flat-top low-noise frequency combs are produced by wave-breaking in ...

  10. Syllable frequency and word frequency effects in spoken and written word production in a non-alphabetic script

    Directory of Open Access Journals (Sweden)

    Qingfang eZhang

    2014-02-01

    Full Text Available The effects of word frequency and syllable frequency are well-established phenomena in domain such as spoken production in alphabetic languages. Chinese, as a non-alphabetic language, presents unique lexical and phonological properties in speech production. For example, the proximate unit of phonological encoding is syllable in Chinese but segments in Dutch, French or English. The present study investigated the effects of word frequency and syllable frequency, and their interaction in Chinese written and spoken production. Significant facilitatory word frequency and syllable frequency effects were observed in spoken as well as in written production. The syllable frequency effect in writing indicated that phonological properties (i.e., syllabic frequency constrain orthographic output via a lexical route, at least, in Chinese written production. However, the syllable frequency effect over repetitions was divergent in both modalities: it was significant in the former two repetitions in spoken whereas it was significant in the second repetition only in written. Due to the fragility of the syllable frequency effect in writing, we suggest that the phonological influence in handwritten production is not mandatory and universal, and it is modulated by experimental manipulations. This provides evidence for the orthographic autonomy hypothesis, rather than the phonological mediation hypothesis. The absence of an interaction between word frequency and syllable frequency showed that the syllable frequency effect is independent of the word frequency effect in spoken and written output modalities. The implications of these results on written production models are discussed.

  11. Developmental trajectories of paediatric headache - sex-specific analyses and predictors.

    Science.gov (United States)

    Isensee, Corinna; Fernandez Castelao, Carolin; Kröner-Herwig, Birgit

    2016-01-01

    Headache is the most common pain disorder in children and adolescents and is associated with diverse dysfunctions and psychological symptoms. Several studies evidenced sex-specific differences in headache frequency. Until now no study exists that examined sex-specific patterns of change in paediatric headache across time and included pain-related somatic and (socio-)psychological predictors. Latent Class Growth Analysis (LCGA) was used in order to identify different trajectory classes of headache across four annual time points in a population-based sample (n = 3 227; mean age 11.34 years; 51.2 % girls). In multinomial logistic regression analyses the influence of several predictors on the class membership was examined. For girls, a four-class model was identified as the best fitting model. While the majority of girls reported no (30.5 %) or moderate headache frequencies (32.5 %) across time, one class with a high level of headache days (20.8 %) and a class with an increasing headache frequency across time (16.2 %) were identified. For boys a two class model with a 'no headache class' (48.6 %) and 'moderate headache class' (51.4 %) showed the best model fit. Regarding logistic regression analyses, migraine and parental headache proved to be stable predictors across sexes. Depression/anxiety was a significant predictor for all pain classes in girls. Life events, dysfunctional stress coping and school burden were also able to differentiate at least between some classes in both sexes. The identified trajectories reflect sex-specific differences in paediatric headache, as seen in the number and type of classes extracted. The documented risk factors can deliver ideas for preventive actions and considerations for treatment programmes.

  12. Low-frequency sound exposure causes reversible long-term changes of cochlear transfer characteristics.

    Science.gov (United States)

    Drexl, Markus; Otto, Larissa; Wiegrebe, Lutz; Marquardt, Torsten; Gürkov, Robert; Krause, Eike

    2016-02-01

    Intense, low-frequency sound presented to the mammalian cochlea induces temporary changes of cochlear sensitivity, for which the term 'Bounce' phenomenon has been coined. Typical manifestations are slow oscillations of hearing thresholds or the level of otoacoustic emissions. It has been suggested that these alterations are caused by changes of the mechano-electrical transducer transfer function of outer hair cells (OHCs). Shape estimates of this transfer function can be derived from low-frequency-biased distortion product otoacoustic emissions (DPOAE). Here, we tracked the transfer function estimates before and after triggering a cochlear Bounce. Specifically, cubic DPOAEs, modulated by a low-frequency biasing tone, were followed over time before and after induction of the cochlear Bounce. Most subjects showed slow, biphasic changes of the transfer function estimates after low-frequency sound exposure relative to the preceding control period. Our data show that the operating point changes biphasically on the transfer function with an initial shift away from the inflection point followed by a shift towards the inflection point before returning to baseline values. Changes in transfer function and operating point lasted for about 180 s. Our results are consistent with the hypothesis that intense, low-frequency sound disturbs regulatory mechanisms in OHCs. The homeostatic readjustment of these mechanisms after low-frequency offset is reflected in slow oscillations of the estimated transfer functions. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadingson Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    This paper discusses the influence of wave load sampling frequency on calculated sliding distance in an overall stability analysis of a monolithic caisson. It is demonstrated by a specific example of caisson design that for this kind of analyses the sampling frequency in a small scale model could...... be as low as 100 Hz in model scale. However, for design of structure elements like the wave wall on the top of a caisson the wave load sampling frequency must be much higher, in the order of 1000 Hz in the model. Elastic-plastic deformations of foundation and structure were not included in the analysis....

  14. Importance of sampling frequency when collecting diatoms

    KAUST Repository

    Wu, Naicheng

    2016-11-14

    There has been increasing interest in diatom-based bio-assessment but we still lack a comprehensive understanding of how to capture diatoms’ temporal dynamics with an appropriate sampling frequency (ASF). To cover this research gap, we collected and analyzed daily riverine diatom samples over a 1-year period (25 April 2013–30 April 2014) at the outlet of a German lowland river. The samples were classified into five clusters (1–5) by a Kohonen Self-Organizing Map (SOM) method based on similarity between species compositions over time. ASFs were determined to be 25 days at Cluster 2 (June-July 2013) and 13 days at Cluster 5 (February-April 2014), whereas no specific ASFs were found at Cluster 1 (April-May 2013), 3 (August-November 2013) (>30 days) and Cluster 4 (December 2013 - January 2014) (<1 day). ASFs showed dramatic seasonality and were negatively related to hydrological wetness conditions, suggesting that sampling interval should be reduced with increasing catchment wetness. A key implication of our findings for freshwater management is that long-term bio-monitoring protocols should be developed with the knowledge of tracking algal temporal dynamics with an appropriate sampling frequency.

  15. Act-Frequency Signatures of the Big Five.

    Science.gov (United States)

    Chapman, Benjamin P; Goldberg, Lewis R

    2017-10-01

    The traditional focus of work on personality and behavior has tended toward "major outcomes" such as health or antisocial behavior, or small sets of behaviors observable over short periods in laboratories or in convenience samples. In a community sample, we examined a wide set (400) of mundane, incidental or "every day" behavioral acts, the frequencies of which were reported over the past year. Using an exploratory methodology similar to genomic approaches (relying on the False Discovery Rate) revealed 26 prototypical acts for Intellect, 24 acts for Extraversion, 13 for Emotional Stability, nine for Conscientiousness, and six for Agreeableness. Many links were consistent with general intuition-for instance, low Conscientiousness with work and procrastination. Some of the most robust associations, however, were for acts too specific for a priori hypothesis. For instance, Extraversion was strongly associated with telling dirty jokes, Intellect with "loung[ing] around [the] house without clothes on", and Agreeableness with singing in the shower. Frequency categories for these acts changed with markedly non-linearity across Big Five Z-scores. Findings may help ground trait scores in emblematic acts, and enrich understanding of mundane or common behavioral signatures of the Big Five.

  16. Triple-frequency GPS precise point positioning with rapid ambiguity resolution

    Science.gov (United States)

    Geng, Jianghui; Bock, Yehuda

    2013-05-01

    At present, reliable ambiguity resolution in real-time GPS precise point positioning (PPP) can only be achieved after an initial observation period of a few tens of minutes. In this study, we propose a method where the incoming triple-frequency GPS signals are exploited to enable rapid convergences to ambiguity-fixed solutions in real-time PPP. Specifically, extra-wide-lane ambiguity resolution can be first achieved almost instantaneously with the Melbourne-Wübbena combination observable on L2 and L5. Then the resultant unambiguous extra-wide-lane carrier-phase is combined with the wide-lane carrier-phase on L1 and L2 to form an ionosphere-free observable with a wavelength of about 3.4 m. Although the noise of this observable is around 100 times the raw carrier-phase noise, its wide-lane ambiguity can still be resolved very efficiently, and the resultant ambiguity-fixed observable can assist much better than pseudorange in speeding up succeeding narrow-lane ambiguity resolution. To validate this method, we use an advanced hardware simulator to generate triple-frequency signals and a high-grade receiver to collect 1-Hz data. When the carrier-phase precisions on L1, L2 and L5 are as poor as 1.5, 6.3 and 1.5 mm, respectively, wide-lane ambiguity resolution can still reach a correctness rate of over 99 % within 20 s. As a result, the correctness rate of narrow-lane ambiguity resolution achieves 99 % within 65 s, in contrast to only 64 % within 150 s in dual-frequency PPP. In addition, we also simulate a multipath-contaminated data set and introduce new ambiguities for all satellites every 120 s. We find that when multipath effects are strong, ambiguity-fixed solutions are achieved at 78 % of all epochs in triple-frequency PPP whilst almost no ambiguities are resolved in dual-frequency PPP. Therefore, we demonstrate that triple-frequency PPP has the potential to achieve ambiguity-fixed solutions within a few minutes, or even shorter if raw carrier-phase precisions are

  17. Reproducibility of frequency-dependent low frequency fluctuations in reaction time over time and across tasks.

    Science.gov (United States)

    Liu, Zan-Zan; Qu, Hui-Jie; Tian, Zhuo-Ling; Han, Meng-Jian; Fan, Yi; Ge, Lie-Zhong; Zang, Yu-Feng; Zhang, Hang

    2017-01-01

    Increased levels of reaction time variability (RTV) are characteristics of sustained attention deficits. The clinical significance of RTV has been widely recognized. However, the reliability of RTV measurements has not been widely studied. The present study aimed to assess the test-retest reliability of RTV conventional measurements, e.g., the standard deviation (SD), the coefficient of variation (CV), and a new measurement called the amplitude of low frequency fluctuation (ALFF) of RT. In addition, we aimed to assess differences and similarities of these measurements between different tasks. Thirty-seven healthy college students participated in 2 tasks, i.e., an Eriksen flanker task (EFT) and a simple reaction task (SRT), twice over a mean interval of 56 days. Conventional measurements of RTV including RT-SD and RT-CV were assessed first. Then the RT time series were converted into frequency domains, and RT-ALFF was further calculated for the whole frequency band (0.0023-0.167 Hz) and for a few sub-frequency bands including Slow-6 (frequency bands (Slow-3), but SRT RT-ALFF values showed slightly higher ICC values than EFT values in lower frequency bands (Slow-5 and Slow-4). 2) RT-ALFF magnitudes in each sub-frequency band were greater for the SRT than those for the EFT. 3) The RT-ALFF in the Slow-4 of the EFT was found to be correlated with the RT-ALFF in the Slow-5 of the SRT for both two visits, but no consistently significant correlation was found between the same frequency bands. These findings reveal good test-retest reliability for conventional measurements and for the RT-ALFF of RTV. The RT-ALFF presented frequency-dependent similarities across tasks. All of our results reveal the presence of different frequency structures between the two tasks, and thus the frequency-dependent characteristics of different tasks deserve more attention in future studies.

  18. Magneto-thermal-acoustic differential-frequency imaging of magnetic nanoparticle with magnetic spatial localization: a theoretical prediction

    Science.gov (United States)

    Piao, Daqing

    2017-02-01

    The magneto-thermo-acoustic effect that we predicted in 2013 refers to the generation of acoustic-pressure wave from magnetic nanoparticle (MNP) when thermally mediated under an alternating magnetic field (AMF) at a pulsed or frequency-chirped application. Several independent experimental studies have since validated magneto-thermoacoustic effect, and a latest report has discovered acoustic-wave generation from MNP at the second-harmonic frequency of the AMF when operating continuously. We propose that applying two AMFs with differing frequencies to MNP will produce acoustic-pressure wave at the summation and difference of the two frequencies, in addition to the two second-harmonic frequencies. Analysis of the specific absorption dynamics of the MNP when exposed to two AMFs of differing frequencies has shown some interesting patterns of acoustic-intensity at the multiple frequency components. The ratio of the acoustic-intensity at the summation-frequency over that of the difference-frequency is determined by the frequency-ratio of the two AMFs, but remains independent of the AMF strengths. The ratio of the acoustic-intensity at the summation- or difference-frequency over that at each of the two second-harmonic frequencies is determined by both the frequency-ratio and the field-strength-ratio of the two AMFs. The results indicate a potential strategy for localization of the source of a continuous-wave magneto-thermalacoustic signal by examining the frequency spectrum of full-field non-differentiating acoustic detection, with the field-strength ratio changed continuously at a fixed frequency-ratio. The practicalities and challenges of this magnetic spatial localization approach for magneto-thermo-acoustic imaging using a simple envisioned set of two AMFs arranged in parallel to each other are discussed.

  19. Investigation of the Relationship Between Electrical Stimulation Frequency and Muscle Frequency Response Under Submaximal Contractions.

    Science.gov (United States)

    Papcke, Caluê; Krueger, Eddy; Olandoski, Marcia; Nogueira-Neto, Guilherme Nunes; Nohama, Percy; Scheeren, Eduardo Mendonça

    2018-03-25

    Neuromuscular electrical stimulation (NMES) is a common tool that is used in clinical and laboratory experiments and can be combined with mechanomyography (MMG) for biofeedback in neuroprostheses. However, it is not clear if the electrical current applied to neuromuscular tissues influences the MMG signal in submaximal contractions. The objective of this study is to investigate whether the electrical stimulation frequency influences the mechanomyographic frequency response of the rectus femoris muscle during submaximal contractions. Thirteen male participants performed three maximal voluntary isometric contractions (MVIC) recorded in isometric conditions to determine the maximal force of knee extensors. This was followed by the application of nine modulated NMES frequencies (20, 25, 30, 35, 40, 45, 50, 75, and 100 Hz) to evoke 5% MVIC. Muscle behavior was monitored by the analysis of MMG signals, which were decomposed into frequency bands by using a Cauchy wavelet transform. For each applied electrical stimulus frequency, the mean MMG spectral/frequency response was estimated for each axis (X, Y, and Z axes) of the MMG sensor with the values of the frequency bands used as weights (weighted mean). Only with respect to the Z (perpendicular) axis of the MMG signal, the stimulus frequency of 20 Hz did not exhibit any difference with the weighted mean (P = 0.666). For the frequencies of 20 and 25 Hz, the MMG signal displayed the bands between 12 and 16 Hz in the three axes (P frequencies from 30 to 100 Hz, the muscle presented a higher concentration of the MMG signal between the 22 and 29 Hz bands for the X and Z axes, and between 16 and 34 Hz bands for the Y axis (P frequency, because their frequency contents tend to mainly remain between the 20- and 25-Hz bands. Hence, NMES does not interfere with the use of MMG in neuroprosthesis. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  20. Broadcast Communication by System Frequency Modulation

    DEFF Research Database (Denmark)

    Douglass, Philip James; You, Shi; Heussen, Kai

    2012-01-01

    Load controllers available today can measure AC system frequency and react to frequency deviations. A system operator can communicate to frequency sensitive loads by changing the set-points of the system’s dispatchable frequency regulation resources. Explicitly signaling system state by generating...... off-nominal system frequency values is a novel narrowband broadcast communications channel between system operators and frequency sensitive distributed energy resources (FS-DER). The feasibility of the proposed system is evaluated on an existing island power system in Denmark. This study shows...... that within standard frequency quality constraints, 4 distinct symbols are feasible on the island. However, the overarching imperative of system stability prevents the symbols from having arbitrary meanings. Higher frequency values must translate into greater consumption from loads, and vice versa. Within...

  1. Frequency conversion of structured light.

    Science.gov (United States)

    Steinlechner, Fabian; Hermosa, Nathaniel; Pruneri, Valerio; Torres, Juan P

    2016-02-15

    Coherent frequency conversion of structured light, i.e. the ability to manipulate the carrier frequency of a wave front without distorting its spatial phase and intensity profile, provides the opportunity for numerous novel applications in photonic technology and fundamental science. In particular, frequency conversion of spatial modes carrying orbital angular momentum can be exploited in sub-wavelength resolution nano-optics and coherent imaging at a wavelength different from that used to illuminate an object. Moreover, coherent frequency conversion will be crucial for interfacing information stored in the high-dimensional spatial structure of single and entangled photons with various constituents of quantum networks. In this work, we demonstrate frequency conversion of structured light from the near infrared (803 nm) to the visible (527 nm). The conversion scheme is based on sum-frequency generation in a periodically poled lithium niobate crystal pumped with a 1540-nm Gaussian beam. We observe frequency-converted fields that exhibit a high degree of similarity with the input field and verify the coherence of the frequency-conversion process via mode projection measurements with a phase mask and a single-mode fiber. Our results demonstrate the suitability of exploiting the technique for applications in quantum information processing and coherent imaging.

  2. Frequency-Specific Abnormalities of Intrinsic Functional Connectivity Strength among Patients with Amyotrophic Lateral Sclerosis: A Resting-State fMRI Study

    Directory of Open Access Journals (Sweden)

    Fangjun Li

    2017-11-01

    Full Text Available The classical concept that amyotrophic lateral sclerosis (ALS is a degenerative disorder characterized by the loss of upper and lower motor neurons is agreed. However, more and more studies have suggested the involvement of some extra-motor regions. The aim of this study is to investigate the frequency-related alteration pattern of intrinsic functional connectivity strength (FCS at the voxel-wise level in the relatively early-stage of ALS on a whole brain scale. In this study, 21 patients with ALS and 21 well-matched healthy control subjects were enrolled to examine the intrinsic FCS in the different frequencies (slow-4: 0.027–0.073 Hz; slow-5: 0.01–0.027 Hz, and typical band: 0.01–0.1 Hz. Compared with the control subjects, the ALS patients showed a significantly decreased FCS in the left prefrontal cortex (PFC and the bilateral superior frontal gyrus. In the slow-5 band, the patients with ALS showed decreased FCS in the left lingual gyrus, as well as increased FCS in the left postcentral gyrus/paracentral lobule (PoCG/PARC. In the slow-4 band, the ALS patients presented decreased FCS in the left and right ventrolateral PFC. Moreover, the increased FCS in the left PoCG/PARC in the slow-5 band was positively correlated with the ALSFRS-r score (P = 0.015. Our results demonstrated that the FCS changes in ALS were wide spread and frequency dependent. These findings may provide some evidences that ALS patients have the consistent impairment in some extra-motor regions at a relatively early-stage.

  3. Frequency Standards and Metrology

    Science.gov (United States)

    Maleki, Lute

    2009-04-01

    Preface / Lute Maleki -- Symposium history / Jacques Vanier -- Symposium photos -- pt. I. Fundamental physics. Variation of fundamental constants from the big bang to atomic clocks: theory and observations (Invited) / V. V. Flambaum and J. C. Berengut. Alpha-dot or not: comparison of two single atom optical clocks (Invited) / T. Rosenband ... [et al.]. Variation of the fine-structure constant and laser cooling of atomic dysprosium (Invited) / N. A. Leefer ... [et al.]. Measurement of short range forces using cold atoms (Invited) / F. Pereira Dos Santos ... [et al.]. Atom interferometry experiments in fundamental physics (Invited) / S. W. Chiow ... [et al.]. Space science applications of frequency standards and metrology (Invited) / M. Tinto -- pt. II. Frequency & metrology. Quantum metrology with lattice-confined ultracold Sr atoms (Invited) / A. D. Ludlow ... [et al.]. LNE-SYRTE clock ensemble: new [symbol]Rb hyperfine frequency measurement - spectroscopy of [symbol]Hg optical clock transition (Invited) / M. Petersen ... [et al.]. Precise measurements of S-wave scattering phase shifts with a juggling atomic clock (Invited) / S. Gensemer ... [et al.]. Absolute frequency measurement of the [symbol] clock transition (Invited) / M. Chwalla ... [et al.]. The semiclassical stochastic-field/atom interaction problem (Invited) / J. Camparo. Phase and frequency noise metrology (Invited) / E. Rubiola ... [et al.]. Optical spectroscopy of atomic hydrogen for an improved determination of the Rydberg constant / J. L. Flowers ... [et al.] -- pt. III. Clock applications in space. Recent progress on the ACES mission (Invited) / L. Cacciapuoti and C. Salomon. The SAGAS mission (Invited) / P. Wolf. Small mercury microwave ion clock for navigation and radioScience (Invited) / J. D. Prestage ... [et al.]. Astro-comb: revolutionizing precision spectroscopy in astrophysics (Invited) / C. E. Kramer ... [et al.]. High frequency very long baseline interferometry: frequency standards and

  4. All-fiber incoherent frequency-to-time mapping method for microwave signal generation with baseband transmission and multicasting support

    DEFF Research Database (Denmark)

    Company Torres, Victor; Tafur Monroy, Idelfonso; Lancis, Jesus

    2008-01-01

    We present a proof-of-principle experiment for achieving simultaneous distribution of baseband radio-frequency data and up-conversion with broadcasting support over a passive optical network. The technique is based on an incoherent frequency-to-time mapping method for pulse shaping. Specifically...... resembles the shape of the incoherent source. The photodetected signal contains both the baseband data and an up-frequency converted copy with central wavelength for the microwave carrier into the ultra-wideband range and tuning capability by selection of the fiber length. (c) 2008 Elsevier B.V. All rights...

  5. Frequency of CCR5Δ32 allele in healthy Bosniak population.

    Directory of Open Access Journals (Sweden)

    Grażyna Adler

    2014-08-01

    Full Text Available Recent evidence has demonstrated the role of CCR5Δ32 in a variety of human diseases: from infectious and inflammatory diseases to cancer. Several studies have confirmed that genetic variants in chemokine receptor CCR5 gene are correlated with susceptibility and resistance to HIV infection. A 32-nucleotide deletion within the CCR5 reading frame is associated with decreased susceptibility to HIV acquisition and a slower progression to AIDS. Mean frequency of CCR5Δ32 allele in Europe is approximately 10%. The highest allele frequency is observed among Nordic populations (about 12% and lower in the regions of Southeast Mediterranean (about 5%. Although the frequency of CCR5Δ32 was determined in numerous European populations, there is a lack of studies on this variant in the Bosnia and Hercegovina population. Therefore, the aim of our study was to assess the frequency of CCR5Δ32 allele in the cohort of Bosniaks and compare the results with European reports. CCR5Δ32 was detected by sequence-specific PCR in a sample of 100 healthy subjects from Bosnia and Herzegovina (DNA collected 2011-2013.  Mean age of the cohort being 58.8 (±10.7 years, with 82% of women. We identified 17 heterozygotes and one mutant homozygote in study group, with mean ∆32 allele frequency of 9.5%. CCR5∆32 allele frequency among Bosniaks is comparable to that found in Caucasian populations and follows the pattern of the north-southern gradient observed for Europe. Further studies on larger cohorts with adequate female-to-male ratio are necessary. 

  6. A study of the high-frequency hearing thresholds of dentistry professionals

    Directory of Open Access Journals (Sweden)

    Lopes, Andréa Cintra

    2012-01-01

    Full Text Available Introduction: In the dentistry practice, dentists are exposed to harmful effects caused by several factors, such as the noise produced by their work instruments. In 1959, the American Dental Association recommended periodical hearing assessments and the use of ear protectors. Aquiring more information regarding dentists', dental nurses', and prosthodontists' hearing abilities is necessary to propose prevention measures and early treatment strategies. Objective: To investigate the auditory thresholds of dentists, dental nurses, and prosthodontists. Method: In this clinical and experimental study, 44 dentists (Group I; GI, 36 dental nurses (Group II; GII, and 28 prosthodontists (Group III; GIII were included, , with a total of 108 professionals. The procedures that were performed included a specific interview, ear canal inspection, conventional and high-frequency threshold audiometry, a speech reception threshold test, and an acoustic impedance test. Results: In the 3 groups that were tested, the comparison between the mean hearing thresholds provided evidence of worsened hearing ability relative to the increase in frequency. For the tritonal mean at 500 to 2,000 Hz and 3,000 to 6,000 Hz, GIII presented the worst thresholds. For the mean of the high frequencies (9,000 and 16,000 Hz, GII presented the worst thresholds. Conclusion: The conventional hearing threshold evaluation did not demonstrate alterations in the 3 groups that were tested; however, the complementary tests such as high-frequency audiometry provided greater efficacy in the early detection of hearing problems, since this population's hearing loss impaired hearing ability at frequencies that are not tested by the conventional tests. Therefore, we emphasize the need of utilizing high-frequency threshold audiometry in the hearing assessment routine in combination with other audiological tests.

  7. Frequency regulated compact screw compressors. The new solution; Drehzahlgeregelte Kompakt-Schraubenverdichter. Die neue Loesung

    Energy Technology Data Exchange (ETDEWEB)

    Juergensen, Heinz [BITZER Kuehlmaschinenbau GmbH, Sindelfingen (Germany)

    2012-07-01

    Compact screw compressors have been used for many years in liquid chilling packages for comfort air conditioners, process cooling or heat pumps with mechanical power control. Standard frequency inverters offer the possibility to adjust the performance of a conventional screw compressor, piston compressor or scroll compressor in a small range of frequency. Furthermore, frequency inverters contain a number of additional functions. This combination of existing frequency inverters and compressors - as actually offered in many cases - allows only a limited improvement of the part-load performance in the system. Due to the high cost for the frequency inverters, this combination becomes economically questionable. An integrated package of newly developed compact screw compressors and a specially developed liquid-cooled frequency inverter is required in order to come to a new level of system efficiency at part load. In addition to the increased control range of the compressor, new possibilities can be opened up in terms of application and communication. The monitoring of various values such as the compliance with the application limits for pressure and temperature and especially the early warning against exceedance facilitates a more simply implementation of a secure machine because the setting of the relevant protection functions of the integrated type-specific components already is made in the factory.

  8. Gyrocon Radio-Frequency-Generator project for FY-78 and -79

    International Nuclear Information System (INIS)

    Tallerico, P.J.; Rankin, J.E.

    1980-09-01

    The gyrocon is a high-power, high-efficiency amplifier that operates by deflection modulation of an electron beam. The bunching is better than that in a klystron, especially for very high powers and UHF frequencies, so the overall efficiency and the maximum output power can be higher than in a klystron. The present theory includes the effects of large signals, space charge, and finite beam size. The equations of motion are relativistically correct, and the space-charge fields are correct to first order in v/c. The theory is derived and a computer code to solve these equations is discussed. The code is then used to obtain several specific examples of gyrocon designs that have significant advantages over klystrons or gridded tubes in the 0.2- to 1.0-GHz frequency range. Several embodiments of the gyrocon are possible: the radial style and the spherical style are discussed in this report. The radial style has a bender magnet to increase the deflection of the beam, whereas the spherical gyrocon does not employ the bender magnet. The optimum frequency range for the spherical gyrocon is from 1.0 to 2.5 GHz

  9. Airborne non-contact and contact broadband ultrasounds for frequency attenuation profile estimation of cementitious materials.

    Science.gov (United States)

    Gosálbez, J; Wright, W M D; Jiang, W; Carrión, A; Genovés, V; Bosch, I

    2018-08-01

    In this paper, the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous cementitious materials is addressed. To accurately determine the attenuation over a wide frequency range, it is necessary to have suitable excitation techniques. We have analysed two kinds of ultrasound techniques: contact ultrasound and airborne non-contact ultrasound. The mathematical formulation for frequency-dependent attenuation has been established and it has been revealed that each technique may achieve similar results but requires specific different calibration processes. In particular, the airborne non-contact technique suffers high attenuation due to energy losses at the air-material interfaces. Thus, its bandwidth is limited to low frequencies but it does not require physical contact between transducer and specimen. In contrast, the classical contact technique can manage higher frequencies but the measurement depends on the pressure between the transducer and the specimen. Cement specimens have been tested with both techniques and frequency attenuation dependence has been estimated. Similar results were achieved at overlapping bandwidth and it has been demonstrated that the airborne non-contact ultrasound technique could be a viable alternative to the classical contact technique. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Frequency Hopping Transceiver Multiplexer

    Science.gov (United States)

    1983-03-01

    ATC 17 ULR IHQ OCLI CPCTR ULTRA HIGH "OQS" UP TO 4X HIGHER THAN BEST INDUS- TRY STANDARD (ATC 100). MICROWAVE POWER, CURRENT. AND 0 RATINGS5...Q"W were assigned to element (FigC-2); which will be modelled into the transformer previously ment td . The center frequencies, "Q", frequency range...of the TD 1288 system. Temperature stability, change with time or storage. Flexure Frequency, or non-linear change over bandwidth. * Humidity

  11. Correlating Nitrile IR Frequencies to Local Electrostatics Quantifies Noncovalent Interactions of Peptides and Proteins.

    Science.gov (United States)

    Deb, Pranab; Haldar, Tapas; Kashid, Somnath M; Banerjee, Subhrashis; Chakrabarty, Suman; Bagchi, Sayan

    2016-05-05

    Noncovalent interactions, in particular the hydrogen bonds and nonspecific long-range electrostatic interactions are fundamental to biomolecular functions. A molecular understanding of the local electrostatic environment, consistently for both specific (hydrogen-bonding) and nonspecific electrostatic (local polarity) interactions, is essential for a detailed understanding of these processes. Vibrational Stark Effect (VSE) has proven to be an extremely useful method to measure the local electric field using infrared spectroscopy of carbonyl and nitrile based probes. The nitrile chemical group would be an ideal choice because of its absorption in an infrared spectral window transparent to biomolecules, ease of site-specific incorporation into proteins, and common occurrence as a substituent in various drug molecules. However, the inability of VSE to describe the dependence of IR frequency on electric field for hydrogen-bonded nitriles to date has severely limited nitrile's utility to probe the noncovalent interactions. In this work, using infrared spectroscopy and atomistic molecular dynamics simulations, we have reported for the first time a linear correlation between nitrile frequencies and electric fields in a wide range of hydrogen-bonding environments that may bridge the existing gap between VSE and H-bonding interactions. We have demonstrated the robustness of this field-frequency correlation for both aromatic nitriles and sulfur-based nitriles in a wide range of molecules of varying size and compactness, including small molecules in complex solvation environments, an amino acid, disordered peptides, and structured proteins. This correlation, when coupled to VSE, can be used to quantify noncovalent interactions, specific or nonspecific, in a consistent manner.

  12. Arctic boundary layer properties and its influence on cloud occurrence frequency, phase and structure in autumn season

    Science.gov (United States)

    Qiu, S.; Dong, X.; Xi, B.

    2017-12-01

    In this study, autumnal boundary layer characteristics and cloud properties have been investigated using data collected at the Atmospheric Radiation Measurement North Slope of Alaska (ARM NSA) site from January 2002 to December 2008. We found that both cloud and planetary boundary layer (PBL) properties can be well distinguished by surface wind directions. When the ARM NSA site is dominated by a northerly wind during the period September- November, the PBL is at near saturation for all three months; while the maximum RH layer varies from low and thin in September, to higher and thicker in October, and then it becomes close to surface again in November. Both the ceilometer and the MPL derived cloud base heights coincide well with the RH maximum layer in the PBL for all three autumnal months. The frequencies of occurrence of mixed phase clouds in September and October are around 60-80% under a northerly wind, which are about 1.5 times higher than those during a southerly wind. Under northerly wind, the PDFs of PBL temperature and specific humidity are narrow and unimodal, with a peak probability around 0.4-0.5. Under a southerly wind, on the other hand, the PBL is both warmer and wetter than northerly wind profiles, which result in lower RH values (10-15% lower) in September and October; and the PDFs of PBL temperature and specific humidity are more evenly distributed with larger distribution range and lower PDF peak values (<0.3). In September, colder and dryer PBL is more favorable for mixed phase cloud formation, cloud occurrence frequency decreases from 90% to 60% as PBL temperature and specific humidity increase. In October, the frequency of occurrence of mixed phase clouds also decreases from 90% to 50-60% as PBL temperature increases. While in November, it increases first and then decreases with increasing PBL temperature and specific humidity. The frequency of occurrence of mixed phase clouds is linearly correlated to PBL RH values: for all three months, it

  13. Gender Identification Using High-Frequency Speech Energy: Effects of Increasing the Low-Frequency Limit.

    Science.gov (United States)

    Donai, Jeremy J; Halbritter, Rachel M

    The purpose of this study was to investigate the ability of normal-hearing listeners to use high-frequency energy for gender identification from naturally produced speech signals. Two experiments were conducted using a repeated-measures design. Experiment 1 investigated the effects of increasing high-pass filter cutoff (i.e., increasing the low-frequency spectral limit) on gender identification from naturally produced vowel segments. Experiment 2 studied the effects of increasing high-pass filter cutoff on gender identification from naturally produced sentences. Confidence ratings for the gender identification task were also obtained for both experiments. Listeners in experiment 1 were capable of extracting talker gender information at levels significantly above chance from vowel segments high-pass filtered up to 8.5 kHz. Listeners in experiment 2 also performed above chance on the gender identification task from sentences high-pass filtered up to 12 kHz. Cumulatively, the results of both experiments provide evidence that normal-hearing listeners can utilize information from the very high-frequency region (above 4 to 5 kHz) of the speech signal for talker gender identification. These findings are at variance with current assumptions regarding the perceptual information regarding talker gender within this frequency region. The current results also corroborate and extend previous studies of the use of high-frequency speech energy for perceptual tasks. These findings have potential implications for the study of information contained within the high-frequency region of the speech spectrum and the role this region may play in navigating the auditory scene, particularly when the low-frequency portion of the spectrum is masked by environmental noise sources or for listeners with substantial hearing loss in the low-frequency region and better hearing sensitivity in the high-frequency region (i.e., reverse slope hearing loss).

  14. Generation of optical frequencies out of the frequency comb of a femtosecond laser for DWDM telecommunication

    International Nuclear Information System (INIS)

    Kim, Y-J; Chun, B J; Kim, Y; Hyun, S; Kim, S-W

    2010-01-01

    We exploit the frequency comb of a fs laser as the frequency ruler to generate reference optical frequencies for multi-channel DWDM (dense wavelength-division-multiplexing) telecommunication. Our fiber-based scheme of single-mode extraction enables on-demand generation of optical frequencies within the telecommunication band with an absolute frequency uncertainty of 9.1×10 -13 . The linewidth of extracted optical modes is less than 1 Hz, and the instability is measured 2.3×10 -15 at 10 s averaging. This outstanding performance of optical frequency generation would lead to a drastic improvement of the spectral efficiency for the next-generation DWDM telecommunication

  15. Robust power system frequency control

    CERN Document Server

    Bevrani, Hassan

    2014-01-01

    This updated edition of the industry standard reference on power system frequency control provides practical, systematic and flexible algorithms for regulating load frequency, offering new solutions to the technical challenges introduced by the escalating role of distributed generation and renewable energy sources in smart electric grids. The author emphasizes the physical constraints and practical engineering issues related to frequency in a deregulated environment, while fostering a conceptual understanding of frequency regulation and robust control techniques. The resulting control strategi

  16. Real-time and high accuracy frequency measurements for intermediate frequency narrowband signals

    Science.gov (United States)

    Tian, Jing; Meng, Xiaofeng; Nie, Jing; Lin, Liwei

    2018-01-01

    Real-time and accurate measurements of intermediate frequency signals based on microprocessors are difficult due to the computational complexity and limited time constraints. In this paper, a fast and precise methodology based on the sigma-delta modulator is designed and implemented by first generating the twiddle factors using the designed recursive scheme. This scheme requires zero times of multiplications and only half amounts of addition operations by using the discrete Fourier transform (DFT) and the combination of the Rife algorithm and Fourier coefficient interpolation as compared with conventional methods such as DFT and Fast Fourier Transform. Experimentally, when the sampling frequency is 10 MHz, the real-time frequency measurements with intermediate frequency and narrowband signals have a measurement mean squared error of ±2.4 Hz. Furthermore, a single measurement of the whole system only requires approximately 0.3 s to achieve fast iteration, high precision, and less calculation time.

  17. Examining the neural correlates of depressive and motor symptoms in Parkinson's disease using Frequency Component Analysis (FCA)

    Science.gov (United States)

    Song, Xiaopeng; Hu, Xiao; Zhou, Shuqin; Liu, Weiguo; Liu, Yijun; Zhu, Huaiqiu; Gao, Jia-Hong

    2016-03-01

    Depression is prevalent among patients with Parkinson's disease (PD); however the pathophysiology of depression in PD is not well understood. In order to investigate how depression and motor impairments differentially and interactively affect specific brain regions in Parkinson's disease, we introduced a new data driven approach, namely Frequency Component Analysis (FCA), to decompose the resting-state functional magnetic resonance imaging data of 59 subjects with Parkinson's disease into different frequency bands. We then evaluated the main effects of motor severity and depression, and their interactive effects on the BOLD-fMRI signal oscillation energy in these specific frequency components. Our results show that the severity of motor symptoms is more negatively correlated with energy in the frequency band of 0.10-0.25Hz in the bilateral thalamus (THA), but more positively correlated with energy in the frequency band of 0.01-0.027Hz in the bilateral postcentral gyrus (PoCG). In contrast, the severity of depressive symptoms is more associated with the higher energy of the high frequency oscillations (>0.1Hz) but lower energy of 0.01-0.027Hz in the bilateral subgenual gyrus (SGC). Importantly, the interaction between motor and depressive symptoms is negatively correlated with the energy of high frequency oscillations (>0.1Hz) in the substantia nigra/ventral tegmental area (SN/VTA), left hippocampus (HIPP), left inferior orbital frontal cortex (OFC), and left temporoparietal junction (TPJ), but positively correlated with the energy of 0.02-0.05Hz in the left inferior OFC, left TPJ, left inferior temporal gyrus (ITG), and bilateral cerebellum. These results demonstrated that FCA was a promising method in interrogating the neurophysiological implications of different brain rhythms. Our findings further revealed the neural bases underlying the interactions as well the dissociations between motor and depressive symptoms in Parkinson's disease.

  18. Preceding weak noise sharpens the frequency tuning and elevates the response threshold of the mouse inferior collicular neurons through GABAergic inhibition.

    Science.gov (United States)

    Wang, Xin; Jen, Philip H-S; Wu, Fei-Jian; Chen, Qi-Cai

    2007-09-05

    In acoustic communication, animals must extract biologically relevant signals that are embedded in noisy environment. The present study examines how weak noise may affect the auditory sensitivity of neurons in the central nucleus of the mouse inferior colliculus (IC) which receives convergent excitatory and inhibitory inputs from both lower and higher auditory centers. Specifically, we studied the frequency sensitivity and minimum threshold of IC neurons using a pure tone probe and a weak white noise masker under forward masking paradigm. For most IC neurons, probe-elicited response was decreased by a weak white noise that was presented at a specific gap (i.e. time window). When presented within this time window, weak noise masking sharpened the frequency tuning curve and increased the minimum threshold of IC neurons. The degree of weak noise masking of these two measurements increased with noise duration. Sharpening of the frequency tuning curve and increasing of the minimum threshold of IC neurons during weak noise masking were mostly mediated through GABAergic inhibition. In addition, sharpening of frequency tuning curve by the weak noise masker was more effective at the high than at low frequency limb. These data indicate that in the real world the ambient noise may improve frequency sensitivity of IC neurons through GABAergic inhibition while inevitably decrease the frequency response range and sensitivity of IC neurons.

  19. Effects of long-term low dose radiation. Epstein-Barr virus-specific antibodies in radiological technologists

    Energy Technology Data Exchange (ETDEWEB)

    Kumagai, Etsuko; Higashida, Yoshiharu; Onomichi, Mitsukazu; Nakamura, Ikuo; Tanoue, Shozo; Tanaka, Ryuji; Kumagai, Takashi; Katsuki, Takato; Sawada, Shozo.

    1988-09-01

    To clarify the long-term effects of occupational exposure to low doses of radiation, Epstein-Barr virus (EBV)-specific antibody titers in sera from 104 radiological technologists (R.T.) and 118 controls in Kumamoto prefecture were measured by the immunofluorescence method. Antibody titers to viral capsid antigen (VCA)-IgG increased with the years of experience as R.T., and the prevalence of abnormal antibody titers to both VCA-IgG and early antigen (EA)-IgG were significantly higher in R.T. with over 15 years of experience or 30 rads of cumulative radiation dose than in the controls. However, there was no correlation between exposure and the frequency of abnormal EBV-associated nuclear antigen (EBNA) antibody titers. The EBV-specific antibody titers of 24 Hiroshima atomic-bomb survivors were also measured. They were similar to those of the R.T. with over 30 years of experience. The EBV-specific antibody titers of R.T. suggest that there may be an impairment of immunologic competence after continuous long-term exposure to low doses of radiation. Also, the correlation of EBV-specific antibody titers and frequency of cells with chromosome aberrations in 53 R.T. was studied. Some correlations were found between the antibody titers to both of the VCA-IgG and EBNA and the frequency of cells with chromosome aberrations.

  20. Frequency of gamma oscillations in humans is modulated by velocity of visual motion

    Science.gov (United States)

    Butorina, Anna V.; Sysoeva, Olga V.; Prokofyev, Andrey O.; Nikolaeva, Anastasia Yu.; Stroganova, Tatiana A.

    2015-01-01

    Gamma oscillations are generated in networks of inhibitory fast-spiking (FS) parvalbumin-positive (PV) interneurons and pyramidal cells. In animals, gamma frequency is modulated by the velocity of visual motion; the effect of velocity has not been evaluated in humans. In this work, we have studied velocity-related modulations of gamma frequency in children using MEG/EEG. We also investigated whether such modulations predict the prominence of the “spatial suppression” effect (Tadin D, Lappin JS, Gilroy LA, Blake R. Nature 424: 312-315, 2003) that is thought to depend on cortical center-surround inhibitory mechanisms. MEG/EEG was recorded in 27 normal boys aged 8–15 yr while they watched high-contrast black-and-white annular gratings drifting with velocities of 1.2, 3.6, and 6.0°/s and performed a simple detection task. The spatial suppression effect was assessed in a separate psychophysical experiment. MEG gamma oscillation frequency increased while power decreased with increasing velocity of visual motion. In EEG, the effects were less reliable. The frequencies of the velocity-specific gamma peaks were 64.9, 74.8, and 87.1 Hz for the slow, medium, and fast motions, respectively. The frequency of the gamma response elicited during slow and medium velocity of visual motion decreased with subject age, whereas the range of gamma frequency modulation by velocity increased with age. The frequency modulation range predicted spatial suppression even after controlling for the effect of age. We suggest that the modulation of the MEG gamma frequency by velocity of visual motion reflects excitability of cortical inhibitory circuits and can be used to investigate their normal and pathological development in the human brain. PMID:25925324

  1. Brain alterations in low-frequency fluctuations across multiple bands in obsessive compulsive disorder.

    Science.gov (United States)

    Giménez, Mònica; Guinea-Izquierdo, Andrés; Villalta-Gil, Victoria; Martínez-Zalacaín, Ignacio; Segalàs, Cinto; Subirà, Marta; Real, Eva; Pujol, Jesús; Harrison, Ben J; Haro, Josep Maria; Sato, Joao R; Hoexter, Marcelo Q; Cardoner, Narcís; Alonso, Pino; Menchón, José Manuel; Soriano-Mas, Carles

    2017-12-01

    The extent of functional abnormalities in frontal-subcortical circuits in obsessive-compulsive disorder (OCD) is still unclear. Although neuroimaging studies, in general, and resting-state functional Magnetic Resonance Imaging (rs-fMRI), in particular, have provided relevant information regarding such alterations, rs-fMRI studies have been typically limited to the analysis of between-region functional connectivity alterations at low-frequency signal fluctuations (i.e., <0.08 Hz). Conversely, the local attributes of Blood Oxygen Level Dependent (BOLD) signal across different frequency bands have been seldom studied, although they may provide valuable information. Here, we evaluated local alterations in low-frequency fluctuations across different oscillation bands in OCD. Sixty-five OCD patients and 50 healthy controls underwent an rs-fMRI assessment. Alterations in the fractional amplitude of low-frequency fluctuations (fALFF) were evaluated, voxel-wise, across four different bands (from 0.01 Hz to 0.25 Hz). OCD patients showed decreased fALFF values in medial orbitofrontal regions and increased fALFF values in the dorsal-medial prefrontal cortex (DMPFC) at frequency bands <0.08 Hz. This pattern was reversed at higher frequencies, where increased fALFF values also appeared in medial temporal lobe structures and medial thalamus. Clinical variables (i.e., symptom-specific severities) were associated with fALFF values across the different frequency bands. Our findings provide novel evidence about the nature and regional distribution of functional alterations in OCD, which should contribute to refine neurobiological models of the disorder. We suggest that the evaluation of the local attributes of BOLD signal across different frequency bands may be a sensitive approach to further characterize brain functional alterations in psychiatric disorders.

  2. Density and relative frequency effects on competitive interactions and resource use in pea–barley intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Andersen, H.K.; Jørnsgaard, B.

    2006-01-01

    or specific grain yield composition are wanted. Keywords: Competition dynamics; Grain quality; Hordeum vulgare; Intercropping; Nitrogen use; Organic farming; Pisum sativum; Weeds; Yield Abbreviations: IC, mixed intercropping; LER, land equivalent ratio; N, nitrogen; REIc, relative efficiency index; SC, sole...... not increase its reliance on atmospheric nitrogen fixation compared to the pea sole crop. With respect to soil nitrogen uptake there were no effect of plant density but a strong effect of the relative frequency of pea in the intercrop, the greater the proportion the lower the uptake. Changes in the competitive...... and tillering ability of barley are seen as likely explanations of lower weed load in the barley dominated crop treatments. This study points at the potential of employing density and relative crop frequency as "regulators" when specific intercrop objectives such as increased competitiveness towards weeds...

  3. Frequency Shifts of Micro and Nano Cantilever Beam Resonators Due to Added Masses

    KAUST Repository

    Bouchaala, Adam M.

    2016-03-21

    We present analytical and numerical techniques to accurately calculate the shifts in the natural frequencies of electrically actuated micro and nano (carbon nanotubes (CNTs)) cantilever beams implemented as resonant sensors for mass detection of biological entities, particularly Escherichia coli (E. coli) and prostate specific antigen (PSA) cells. The beams are modeled as Euler-Bernoulli beams, including the nonlinear electrostatic forces and the added biological cells, which are modeled as discrete point masses. The frequency shifts due to the added masses of the cells are calculated for the fundamental and higher-order modes of vibrations. Analytical expressions of the natural frequency shifts under a direct current (DC) voltage and an added mass have been developed using perturbation techniques and the Galerkin approximation. Numerical techniques are also used to calculate the frequency shifts and compared with the analytical technique. We found that a hybrid approach that relies on the analytical perturbation expression and the Galerkin procedure for calculating accurately the static behavior presents the most computationally efficient approach. We found that using higher-order modes of vibration of micro-electro-mechanical-system (MEMS) beams or miniaturizing the sizes of the beams to nanoscale leads to significant improved frequency shifts, and thus increased sensitivities. © 2016 by ASME.

  4. The PolyMAX Frequency-Domain Method: A New Standard for Modal Parameter Estimation?

    Directory of Open Access Journals (Sweden)

    Bart Peeters

    2004-01-01

    Full Text Available Recently, a new non-iterative frequency-domain parameter estimation method was proposed. It is based on a (weighted least-squares approach and uses multiple-input-multiple-output frequency response functions as primary data. This so-called “PolyMAX” or polyreference least-squares complex frequency-domain method can be implemented in a very similar way as the industry standard polyreference (time-domain least-squares complex exponential method: in a first step a stabilisation diagram is constructed containing frequency, damping and participation information. Next, the mode shapes are found in a second least-squares step, based on the user selection of stable poles. One of the specific advantages of the technique lies in the very stable identification of the system poles and participation factors as a function of the specified system order, leading to easy-to-interpret stabilisation diagrams. This implies a potential for automating the method and to apply it to “difficult” estimation cases such as high-order and/or highly damped systems with large modal overlap. Some real-life automotive and aerospace case studies are discussed. PolyMAX is compared with classical methods concerning stability, accuracy of the estimated modal parameters and quality of the frequency response function synthesis.

  5. Micronuclei Frequency in Radiation Worker

    International Nuclear Information System (INIS)

    Sudprasert, Wanwisa; Jungtanasombut, Amornrat; Pakkong, Pannee

    2009-07-01

    Full text: The purpose of this study is to determine the micronuclei (MN) frequency in peripheral blood lymphocytes of 31 individuals occupationally exposed to radiation compared to 24 controls. The effect of donor gender, age, alcoholic consumption, tea/coffee consumption and radiation burden on MN frequency was studied. The results showed that MN frequencies observed for exposed employees were significantly higher than in controls (p = 0.000). The average MN frequency in control was 39.1 ± 3.7 MN/1000 BN while those of exposed group were 60.9 ± 12.3, 61.6 ± 13.0 and 62.6 ± 11.8 MN/1000 BN for the range of accumulative doses at 0.01-3.00, 3.01-6.00 and 6.01-9.00 mSv, respectively. Moreover, MN frequency showed a positive trend with increased accumulative doses as a linear-quadratic relation (R 2 = 0.4754). No correlation of MN frequency with gender, age and alcoholic consumption could be observed in both exposed and control groups. However, the effect of tea/coffee consumption on MN frequency was clearly observed in the exposed individuals (t-test = -2.018, sig. (2-tailed) = 0.030). These results indicate that the increased MN frequency, an indicator of chromosomal aberration, is associated with occupational exposure to low doses of ionizing radiation

  6. An odd couple – Corpus frequency and look-up frequency: what relationship?

    Directory of Open Access Journals (Sweden)

    Lars Trap-Jensen

    2014-12-01

    Full Text Available In this paper, we investigate the relationship between log file records and corpus frequency. The study was motivated by practical considerations of how best to keep an already existing corpus-based dictionary updated. Should the next word in the dictionary be the one that follows next on a list of declining corpus frequency? Or the one that users most frequently look up but don’t find? In order to establish manageable criteria, we analysed log files for The Danish Dictionary from 2009 to 2012 and compared the list of most popular words looked up by the users with the frequency of the same words in the corpus underlying The Danish Dictionary. The users’ actual search behaviour was analysed in order to find answers to questions such as these: Are there words which are never looked up? If so, can we say something meaningful about their corpus frequency patterns – do they belong to particular parts of speech, are they particularly frequent or infrequent, could it even be that the pattern is cumulative, in such a way that a particular threshold can be identified? Ultimately, the question is whether it makes sense to use corpus frequency as a criterion for lemma selection.

  7. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  8. Electric current - frequency converter

    International Nuclear Information System (INIS)

    Kumahara, Tadashi; Kinbana, Setsuro.

    1967-01-01

    Herein disclosed is an improved simple electric current-frequency converter, the input current and output frequency linearity of which is widened to a range of four to five figures while compensating, for temperature. The converter may be used for computor processing and for telemetering the output signals from a nuclear reactor. The converter is an astable multivibrator which includes charging circuits comprising emitter-voltage compensated NPN transistors, a charged voltage detecting circuit of temperature compensated field effect transistors, and a transistor switching circuit for generating switching pulses independent of temperature. The converter exhibited a 0.7% frequency change within a range of 5 - 45 0 C and less than a 0.1% frequency drift after six hours of operation when the input current was maintained constant. (Yamaguchi, T.)

  9. Standards for Measurements in the Field of High Frequency Electromagnetic Radiation for the Purpose of Protection Against Adverse Health Effects

    International Nuclear Information System (INIS)

    Tanatarec, B.; Nikolic, N.

    2011-01-01

    In this paper standards for measurements in the field of high frequency electromagnetic radiation are described with a view to protection from its hazardous action. Beside the standards which directly deal with high frequency electromagnetic radiation measurements, guidelines which describe hazardous influences of high frequency electromagnetic radiation on human body in the form of specific absorption rate (SAR) are given. Special attention is dedicated to standards and regulations, which are dealing with social responsibility, as well as with social responsibility in the field of high frequency radiation. This area is new and insufficiently known, rarely extended in everyday life. (author)

  10. Impact-driven, frequency up-converting coupled vibration energy harvesting device for low frequency operation

    International Nuclear Information System (INIS)

    Gu, Lei; Livermore, Carol

    2011-01-01

    This paper presents experiments and models of an energy harvesting device in which a low frequency resonator impacts a high frequency energy harvesting resonator, resulting in energy harvesting predominantly at the system's coupled vibration frequency. Analysis shows that a reduced mechanical damping ratio during coupled vibration enables increased electrical power generation as compared with conventional technology. Experiments demonstrate that the efficiency of electrical power transfer is significantly improved with the coupled vibration approach. An average power output of 0.43 mW is achieved under 0.4g acceleration at 8.2 Hz, corresponding to a power density of 25.5 µW cm −3 . The measured power and power density at the resonant frequency are respectively 4.8 times and 13 times the measured peak values for a conventional harvester created from a low frequency beam alone

  11. ICT Based Performance Evaluation of Primary Frequency Control Support from Renewable Power Plants in Smart Grids

    Directory of Open Access Journals (Sweden)

    Kamal Shahid

    2018-05-01

    Full Text Available The increased penetration of Renewable Energy Generation (ReGen plants in future power systems poses several challenges to the stability of the entire system. In future green energy rich power systems, the responsibility for providing ancillary services will be shifted from conventional power plants towards ReGen plants, such as wind and photovoltaic power plants. Frequency control support from the Wind Power Plants (WPPs is one of the crucial ancillary services in order to preserve operational stability in case of grid disturbances. Among other requirements, the ability to provide fast frequency control support from ReGen plants will highly depend on the underlying communication infrastructure that allows an exchange of information between different ReGen plants and the control centers. This paper, therefore, focuses on the evaluation of the impact of communication and the related aspects to provide online frequency control support from ReGen (with special focus on WPP. The performance evaluation is based on an aggregated WPP model that is integrated into a generic power system model. This generic power system model is specifically designed to assess the ancillary services in a relatively simple yet relevant environment. Several case studies with different wind speeds at a particular wind-power penetration level and communication scenarios are considered to evaluate the performance of power system frequency response. The article provides the Transmission System Operator (TSO and other communication engineers insights into the importance and various aspects of communication infrastructure for general service coordination between WPPs and specifically primary frequency control coordination from WPPs in future power systems.

  12. THE IMPACT OF FREQUENCY STANDARDS ON COHERENCE IN VLBI AT THE HIGHEST FREQUENCIES

    Energy Technology Data Exchange (ETDEWEB)

    Rioja, M.; Dodson, R. [ICRAR, University of Western Australia, Perth (Australia); Asaki, Y. [Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuou, Sagamihara, Kanagawa 252-5210 (Japan); Hartnett, J. [School of Physics, University of Western Australia, Perth (Australia); Tingay, S., E-mail: maria.rioja@icrar.org [ICRAR, Curtin University, Perth (Australia)

    2012-10-01

    We have carried out full imaging simulation studies to explore the impact of frequency standards in millimeter and submillimeter very long baseline interferometry (VLBI), focusing on the coherence time and sensitivity. In particular, we compare the performance of the H-maser, traditionally used in VLBI, to that of ultra-stable cryocooled sapphire oscillators over a range of observing frequencies, weather conditions, and analysis strategies. Our simulations show that at the highest frequencies, the losses induced by H-maser instabilities are comparable to those from high-quality tropospheric conditions. We find significant benefits in replacing H-masers with cryocooled sapphire oscillator based frequency references in VLBI observations at frequencies above 175 GHz in sites which have the best weather conditions; at 350 GHz we estimate a 20%-40% increase in sensitivity over that obtained when the sites have H-masers, for coherence losses of 20%-10%, respectively. Maximum benefits are to be expected by using co-located Water Vapor Radiometers for atmospheric correction. In this case, we estimate a 60%-120% increase in sensitivity over the H-maser at 350 GHz.

  13. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    International Nuclear Information System (INIS)

    Ju, S; Chae, S H; Choi, Y; Jun, S; Park, S M; Lee, S; Ji, C-H; Lee, H W

    2013-01-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken

  14. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    Science.gov (United States)

    Ju, S.; Chae, S. H.; Choi, Y.; Jun, S.; Park, S. M.; Lee, S.; Lee, H. W.; Ji, C.-H.

    2013-12-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low