WorldWideScience

Sample records for junk wideband junk

  1. Toward Junking Junk Foods.

    Science.gov (United States)

    Lehmann, Phyllis E.

    1978-01-01

    Carroll County, Maryland, has shaped a strategy to improve school nutrition by weakening or eliminating, where possible, junk food competition, making lunches more nourishing and appealing, and working nutrition instruction into other subject areas. Steps taken to accomplish these changes are described. (MF)

  2. Junk Food in Schools and Childhood Obesity

    Science.gov (United States)

    Datar, Ashlesha; Nicosia, Nancy

    2012-01-01

    Despite limited empirical evidence, there is growing concern that junk food availability in schools has contributed to the childhood obesity epidemic. In this paper, we estimate the effects of junk food availability on body mass index (BMI), obesity, and related outcomes among a national sample of fifth graders. Unlike previous studies, we address…

  3. Junk Food in Schools and Childhood Obesity

    OpenAIRE

    Datar, Ashlesha; Nicosia, Nancy

    2012-01-01

    Despite limited empirical evidence, there is growing concern that junk food availability in schools has contributed to the childhood obesity epidemic. In this paper, we estimate the effects of junk food availability on BMI, obesity, and related outcomes among a national sample of fifth-graders. Unlike previous studies, we address the endogeneity of the school food environment by controlling for children’s BMI at school entry and estimating instrumental variables regressions that leverage vari...

  4. Junk Food in Schools and Childhood Obesity.

    Science.gov (United States)

    Datar, Ashlesha; Nicosia, Nancy

    2012-01-01

    Despite limited empirical evidence, there is growing concern that junk food availability in schools has contributed to the childhood obesity epidemic. In this paper, we estimate the effects of junk food availability on BMI, obesity, and related outcomes among a national sample of fifth-graders. Unlike previous studies, we address the endogeneity of the school food environment by controlling for children's BMI at school entry and estimating instrumental variables regressions that leverage variation in the school's grade span. Our main finding is that junk food availability does not significantly increase BMI or obesity among this fifth grade cohort despite the increased likelihood of in-school junk food purchases. The results are robust to alternate measures of junk food availability including school administrator reports of sales during school hours, school administrator reports of competitive food outlets, and children's reports of junk food availability. Moreover, the absence of any effects on overall food consumption and physical activity further support the null findings for BMI and obesity.

  5. A Theory of LTR Junk-food Consumption

    OpenAIRE

    Levy, Amnon

    2003-01-01

    LTR junk-food consumption balances the marginal satisfaction with the marginal deterioration of health. An LTR person discounts the instantaneous marginal satisfaction from junk-food consumption by its implications for his survival probability. His change rate of health evaluation is increased (decreased) by junk-food consumption when health is better (worse) than a critical level. The moderating direct effects of age and relative price on junk-food consumption may be amplified, or dimmed, by...

  6. A Theory of Rational Junk-Food Consumption

    OpenAIRE

    Levy, Amnon

    2002-01-01

    An expected lifetime-utility maximizing diet of junk and health food is analyzed. The stationary junk-food consumption level is equal to the ratio of the recovery capacity of a perfectly healthy person to the sensitivity of her health to junk food. The greater the difference between the relative taste and the stationary relative price of junk food, rate of time preference, and elasticity of satisfaction from food, the better the stationary health of the rational junk-food consumer. The greate...

  7. Size Matters, if You Control Your Junk

    DEFF Research Database (Denmark)

    Asness, Clifford S.; Frazzini, Andrea; Israel, Ronen

    that do not rely on market prices, is weak internationally, and is subsumed by proxies for illiquidity. We find, however, that these challenges are dismantled when controlling for the quality, or the inverse "junk", of a firm. A significant size premium emerges, which is stable through time, robust...... to the specification, more consistent across seasons and markets, not concentrated in microcaps, robust to non-price based measures of size, and not captured by an illiquidity premium. Controlling for quality/junk also explains interactions between size and other return characteristics such as value and momentum.......The size premium has been challenged along many fronts: it has a weak historical record, varies significantly over time, in particular weakening after its discovery in the early 1980s, is concentrated among microcap stocks, predominantly resides in January, is not present for measures of size...

  8. Junk Food, Health and Productivity: Taste, Price, Risk and Rationality

    OpenAIRE

    Levy, Amnon

    2006-01-01

    Junk-food consumption, health and productivity are analyzed within an expectedlifetime- utility-maximizing framework in which the probability of living and productivity rise with health and health deteriorate with the consumption of junkfood. So long that the junk food’s relative taste-price differential is positive, the rational diet deviates from the physiologically optimal and renders the levels of health and productivity lower than the maximal. Taxing junk-food can eliminate this discrepa...

  9. Taxing Junk Food to Counter Obesity

    Science.gov (United States)

    Franck, Caroline; Grandi, Sonia M.

    2013-01-01

    We examined the advantages and disadvantages of implementing a junk food tax as an intervention to counter increasing obesity in North America. Small excise taxes are likely to yield substantial revenue but are unlikely to affect obesity rates. High excise taxes are likely to have a direct impact on weight in at-risk populations but are less likely to be politically palatable or sustainable. Ultimately, the effectiveness of earmarked health programs and subsidies is likely to be a key determinant of tax success in the fight against obesity. PMID:24028245

  10. Taxing junk food to counter obesity.

    Science.gov (United States)

    Franck, Caroline; Grandi, Sonia M; Eisenberg, Mark J

    2013-11-01

    We examined the advantages and disadvantages of implementing a junk food tax as an intervention to counter increasing obesity in North America. Small excise taxes are likely to yield substantial revenue but are unlikely to affect obesity rates. High excise taxes are likely to have a direct impact on weight in at-risk populations but are less likely to be politically palatable or sustainable. Ultimately, the effectiveness of earmarked health programs and subsidies is likely to be a key determinant of tax success in the fight against obesity.

  11. Transposable Elements: No More 'Junk DNA'

    Directory of Open Access Journals (Sweden)

    Yun-Ji Kim

    2012-12-01

    Full Text Available Since the advent of whole-genome sequencing, transposable elements (TEs, just thought to be 'junk' DNA, have been noticed because of their numerous copies in various eukaryotic genomes. Many studies about TEs have been conducted to discover their functions in their host genomes. Based on the results of those studies, it has been generally accepted that they have a function to cause genomic and genetic variations. However, their infinite functions are not fully elucidated. Through various mechanisms, including de novo TE insertions, TE insertion-mediated deletions, and recombination events, they manipulate their host genomes. In this review, we focus on Alu, L1, human endogenous retrovirus, and short interspersed element/variable number of tandem repeats/Alu (SVA elements and discuss how they have affected primate genomes, especially the human and chimpanzee genomes, since their divergence.

  12. The effects of banning advertising in junk food markets

    OpenAIRE

    Dubois, Pierre; Griffith, Rachel; O'Connell, Martin

    2016-01-01

    There are growing calls to restrict advertising of junk foods. Whether such a move will improve diet quality will depend on how advertising shifts consumer demands and how firms respond. We study an important and typical junk food market { the potato chips market. We exploit consumer level exposure to adverts to estimate demand, allowing advertising to potentially shift the weight consumers place on product healthiness, tilt demand curves, have dynamic effects and spillover effects across bra...

  13. The effects of banning advertising in junk food markets

    OpenAIRE

    Dubois, Pierre; Griffith, Rachel; O'Connell, Martin

    2017-01-01

    There are growing calls to restrict advertising of junk foods. Whether such a move will improve diet quality will depend on how advertising shifts consumer demands and how firms respond. We study an important and typical junk food market – the potato chips market. We exploit consumer level exposure to adverts to estimate demand, allowing advertising to potentially shift the weight consumers place on product healthiness, tilt demand curves, have dynamic effects and spillover effects across bra...

  14. The project for virus mails and junk mails

    International Nuclear Information System (INIS)

    Qi Fazhi; Shou Xuejian

    2003-01-01

    Along with the application of network, Email is becoming more and more important for people's communication. But like other net work applications, Email is being infracted by Virus Mails and Junk mails. Sendmail and Procmail are used to deal with Virus Mails and Junk mails in this paper. It is effective to prevent the IHCP (Institute of High Energy Physics Academia Sinica) mail server from attacks now

  15. How Some School Boards Are Fighting (and Why More Are Tolerating) Junk Foods in Schools

    Science.gov (United States)

    Aburdene, Patricia

    1977-01-01

    While some school boards refuse to ban junk foods because of the loss of revenue that would result, other boards and administrators are successfully banning junk foods and finding alternatives to them. (IRT)

  16. A theoretical analysis of rational diet of healthy and junk foods

    OpenAIRE

    Levy, Amnon

    2007-01-01

    Junk-food consumption, health and productivity are analysed within an expectedlifetime- utility-maximising framework in which longevity and productivity rise with health, and health deteriorates with the consumption of junk food. As long as the junk food’s relative taste-price differential is positive, rational diets deviate from the physiologically optimal ones and generate lower than maximal levels of health and productivity. Taxing junk food can eliminate this discrepancy, but the outcome ...

  17. Paparan iklan junk food dan pola konsumsi junk food sebagai faktor risiko terjadinya obesitas pada anak sekolah dasar kota dan desa di Daerah Istimewa Yogyakarta

    OpenAIRE

    Esti Nurwanti; Hamam Hadi; Madarina Julia

    2016-01-01

    ABSTRACTBackground: Increasing prevalence of obesity may be caused by junk food advertised while children are watching television.Preference for foods requested by the children is much infl uenced by junk food advertisement, so that it can affect calori intakeand correlates with obesity. Obesity in children can cause obesity during adulthood and may increase the risk of degenerativedisease, like diabetes and cardiovascular.Objective: To analyze the level of risk exposure to junk food advertisi...

  18. Konsumsi Junk Food dan Hipertensi pada Lansia di Kecamatan Kasihan, Bantul, Yogyakarta

    Directory of Open Access Journals (Sweden)

    Rantiningsih Sumarni

    2015-07-01

    Full Text Available The risk of hypertension increases in line with a changes in modern lifestyle. Elderly tends to select food such as junk food with high calories, and fat, but low in fi ber and other nutrients. Junk food contains high amounts of sodium that can increase the volume of blood in the body, so make stronger heart blood pumps and cause the higher blood pressure (hypertension. The purpose of this study was to identify the relationship between junk food consumption and hypertension in elderly in Kasihan sub-district Bantul, Yogyakarta. This was an observational analytic study with cross sectional design. The samples were 100 elderly lives in Kasihan sub-district Bantul, Yogyakarta. The results showed that there was relationship between the consumption of junk food and hypertension. Respondents who suffered from hypertension were 49 (67.1% who often consumed junk food and 24 respondents (32.9% who rarely consumed junk food. Respondents who did not undergo hypertension were 9 respondents (33.3% that often consumed junk food and 18 respondents (66.7% that rarely consumed junk food. In conclusion, there was a relationship between junk food consumption and hypertension in elderly. Risk of hypertension in respondents who consumed more often junk food were 4.083 times higher than them who rarely consumed junk food.

  19. [Junk food consumption and child nutrition. Nutritional anthropological analysis].

    Science.gov (United States)

    Jackson, Portia; Romo, Marcela M; Castillo, Marcela A; Castillo-Durán, Carlos

    2004-10-01

    The increasing consumption of junk food and snacks in Chile in recent years and its association with marketing strategies and prevalent diseases, is reviewed. In the context of world economy, junk food is a global phenomenon. The availability of junk food and snacks at low prices and marketing has triggered an evolution of consumption of foods that require neither the structure nor the preparation of a formal meal. Many studies have suggested that the increase in snack consumption is associated with an increase in obesity, tooth decay and other chronic diseases among children and adolescents. The hypothesis suggests a link between the pattern of snack consumption and an increase increase in the energy density of food consumed, a decrease in satiety, passive over consumption, and an increase in obesity. Between 1977 and 1996, the contribution: of snacks to daily energy intake among children between 2 and 5 years increased by 30% in the United States. In each age group in Chile the frequency of non-transmissible chronic diseases is increasing due primarily to a westernized diet that is high in fat, cholesterol, sodium, and sugar and a sedentary lifestyle. Education about junk food consumption and healthy eating habits in the family, starling since childbirth and public policies about healthy lifestyles should be strengthened.

  20. Time to Take a Stand against Junk Food.

    Science.gov (United States)

    Jacobsen, Michael

    1993-01-01

    Childhood obesity is a social and health problem that is encouraged by junk food ads and the easy availability of unhealthful fast foods. The article provides guidance for parents to encourage healthy eating by their children; it includes a list of resources and a list of "best" processed foods. (SM)

  1. A Force Transducer from a Junk Electronic Balance

    Science.gov (United States)

    Aguilar, Horacio Munguia; Aguilar, Francisco Armenta

    2009-01-01

    It is shown how the load cell from a junk electronic balance can be used as a force transducer for physics experiments. Recovering this device is not only an inexpensive way of getting a valuable laboratory tool but also very useful didactic work on electronic instrumentation. Some experiments on mechanics with this transducer are possible after a…

  2. Radiological control of the junk exports in Cuba

    International Nuclear Information System (INIS)

    Dominguez L, O.; Capote F, E.; Carrazana G, J.A.; Zerquera, J.T.; Ramos V, O.; Alonso A, D.; Fernandez, I.M.; Caveda R, C.A.; Madrazo M, S.; Barroso P, I.

    2006-01-01

    Even when in Cuba a strict control exists on the radiation sources that enter to the country to be used in the different applications, it can be given the case that sources or contaminated materials that never were under this control due fundamentally to that entered to the country before the same one existed, appear in the junk that is marketed. In our country it is effective the Combined Resolution CITMA-MINCEX dated on April, 2002 that settles down the necessity and obligation that has all that manipulates, imports, exports or process junk of carrying out it a radiological control. From April, 2002 making use of a minimum of resources, an own methodology, a properly qualified personnel and the support of a credited laboratory by the ISO 17025 standard, the radioactivity measurement service in junk belonging to the Center of Protection and Hygiene of the Radiations (CPHR), it has reduced the risks that sources or contaminated materials are found in the junk that is exported in the main exporter companies of this line in Cuba avoiding possible radiological emergency situations that affect the population and the environment. (Author)

  3. Attack of the Junk Food Giant: Giving Children and Teens a Taste for Nutrition in an Age of Super Size Portions and Junk Food.

    Science.gov (United States)

    Anderson, Marilyn

    2001-01-01

    Discusses what parents can do to ensure their children's healthy eating, examining whether students are eating school lunches or junk food in the cafeteria; discussing junk food temptations outside of school; noting rising soda consumption rates; and presenting advice for healthy eating (e.g., include children in meal planning and preparation and…

  4. Alu Mobile Elements: From Junk DNA to Genomic Gems

    Directory of Open Access Journals (Sweden)

    Sami Dridi

    2012-01-01

    Full Text Available Alus, the short interspersed repeated sequences (SINEs, are retrotransposons that litter the human genomes and have long been considered junk DNA. However, recent findings that these mobile elements are transcribed, both as distinct RNA polymerase III transcripts and as a part of RNA polymerase II transcripts, suggest biological functions and refute the notion that Alus are biologically unimportant. Indeed, Alu RNAs have been shown to control mRNA processing at several levels, to have complex regulatory functions such as transcriptional repression and modulating alternative splicing and to cause a host of human genetic diseases. Alu RNAs embedded in Pol II transcripts can promote evolution and proteome diversity, which further indicates that these mobile retroelements are in fact genomic gems rather than genomic junks.

  5. Association of junk food consumption with high blood pressure and obesity in Iranian children and adolescents: the Caspian‐IV Study

    Directory of Open Access Journals (Sweden)

    Moloud Payab

    2015-03-01

    Conclusion: It was found that junk food consumption increased the risk of both general and abdominal obesity; therefore, consumption of junk food should be reduced via restricting TV advertisements and increasing taxes on junk foods.

  6. Identity Theft in the Academic World Leads to Junk Science.

    Science.gov (United States)

    Dadkhah, Mehdi; Lagzian, Mohammad; Borchardt, Glenn

    2018-02-01

    In recent years, identity theft has been growing in the academic world. Cybercriminals create fake profiles for prominent scientists in attempts to manipulate the review and publishing process. Without permission, some fraudulent journals use the names of standout researchers on their editorial boards in the effort to look legitimate. This opinion piece, highlights some of the usual types of identity theft and their role in spreading junk science. Some general guidelines that editors and researchers can use against such attacks are presented.

  7. The impact of junk food marketing regulations on food sales: an ecological study.

    Science.gov (United States)

    Kovic, Y; Noel, J K; Ungemack, J A; Burleson, J A

    2018-06-01

    To evaluate the impact of junk food broadcast marketing policies on nationwide junk food sales and identify policy characteristics effective in reducing sales. Country policy data (n = 79) were categorized in a thorough literature review and analysed using a repeated measures design against data on food sales per capita. Study conducted in United States, 2017. Countries with junk food broadcast marketing policies saw a decrease in junk food sales per capita after implementation, while those without said policies saw an increase (p = 0.013). Countries with statutory policies saw a decrease in sales per capita, while those with only self-regulation saw an increase (p = 0.004). Audience restrictions (p = 0.024) and standardized nutrition criteria (p = 0.008) were policy characteristics significantly associated with a decrease in sales per capita. Utilizing a novel approach to evaluate junk food broadcast marketing policies, the study demonstrated that countries with statutory policies saw a significant decrease in junk food sales per capita not seen in countries with no or only self-regulatory policies. To effectively reduce exposure to child-targeted junk food marketing, governments should establish strong, comprehensive statutory regulations. Additionally, countries that implement junk food marketing policies can use food sales data to track policy effectiveness. © 2018 World Obesity Federation.

  8. 28 CFR 25.56 - Responsibilities of junk yards and salvage yards and auto recyclers.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Responsibilities of junk yards and salvage yards and auto recyclers. 25.56 Section 25.56 Judicial Administration DEPARTMENT OF JUSTICE... Responsibilities of junk yards and salvage yards and auto recyclers. (a) By no later than March 31, 2009, and...

  9. Junk food consumption and screen time: association with childhood adiposity.

    Science.gov (United States)

    Montoye, Alexander H; Pfeiffer, Karin A; Alaimo, Katherine; Betz, Heather Hayes; Paek, Hye-Jin; Carlson, Joseph J; Eisenmann, Joey C

    2013-05-01

    To determine the joint association of junk food consumption (JFC) and screen time (ST) with adiposity in children. Two hundred fourteen (121 girls, 93 boys) third-to-fifth-grade students (54% Hispanic, 35% African American, 8% white) completed a lifestyle behavior survey, which included self-reported JFC and ST, as part of a school-based lifestyle intervention program. Neither JFC nor ST, independently or jointly, was associated with adiposity measures. JFC and ST were significantly correlated (r = .375). The low achievement of physical activity and screen time recommendations and high prevalence of overweight/obesity in this mostly minority, low socioeconomic status population indicates a potential focus for intervention.

  10. The impact of a junk-food diet during development on 'wanting' and 'liking'.

    Science.gov (United States)

    Lesser, Ellen Nacha; Arroyo-Ramirez, Aime; Mi, Sarah Jingyi; Robinson, Mike James Ferrar

    2017-01-15

    The global increase in obesity rates has been tied to the rise in junk-food availability and consumption. Increasingly, children are exposed to a junk-food diet during gestation and early development. Excessive consumption of junk-food during this period may negatively impact the development of brain motivation and reward pathways. In this study we investigated the effects of a chronic junk-food diet throughout development on cue-motivated behavior ('wanting'), hedonic 'liking' for sweet tastes, as well as anxiety and weight gain in male and female Long-Evans (LE) and Sprague-Dawley (SD) rats. Here we found that chronic exposure to a junk-food diet resulted in large individual differences in weight gain (gainers and non-gainers) despite resulting in stunted growth as compared to chow-fed controls. Behaviorally, junk-food exposure attenuated conditioned approach (autoshaping) in females, particularly in non-gainers. In contrast, junk-food exposed rats that gained the most weight were willing to work harder for access to a food cue (conditioned reinforcement), and were more attracted to a junk-food context (conditioned place preference) than non-gainers. Hedonic 'liking' reactions (taste reactivity) were severely blunted in LE, but not SD rats, and 'liking' for sucrose negatively correlated with greater weight gain. Finally, junk-food exposure reduced anxiety-like behavior (elevated plus maze) in males but not females. These results suggest that junk-food exposure during development may give rise to dissociable differences in 'liking' and 'wanting' neural systems that do not depend on weight gain and may not be detected through Body Mass Index monitoring alone. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. A maternal 'junk food' diet in pregnancy and lactation promotes an exacerbated taste for 'junk food' and a greater propensity for obesity in rat offspring.

    Science.gov (United States)

    Bayol, Stéphanie A; Farrington, Samantha J; Stickland, Neil C

    2007-10-01

    Obesity is generally associated with high intake of junk foods rich in energy, fat, sugar and salt combined with a dysfunctional control of appetite and lack of exercise. There is some evidence to suggest that appetite and body mass can be influenced by maternal food intake during the fetal and suckling life of an individual. However, the influence of a maternal junk food diet during pregnancy and lactation on the feeding behaviour and weight gain of the offspring remains largely uncharacterised. In this study, six groups of rats were fed either rodent chow alone or with a junk food diet during gestation, lactation and/or post-weaning. The daily food intakes and body mass were measured in forty-two pregnant and lactating mothers as well as in 216 offspring from weaning up to 10 weeks of age. Results showed that 10 week-old rats born to mothers fed the junk food diet during gestation and lactation developed an exacerbated preference for fatty, sugary and salty foods at the expense of protein-rich foods when compared with offspring fed a balanced chow diet prior to weaning or during lactation alone. Male and female offspring exposed to the junk food diet throughout the study also exhibited increased body weight and BMI compared with all other offspring. This study shows that a maternal junk food diet during pregnancy and lactation may be an important contributing factor in the development of obesity.

  12. The impact of junk foods on the adolescent brain.

    Science.gov (United States)

    Reichelt, Amy C; Rank, Michelle M

    2017-12-01

    Adolescence is a significant period of physical, social, and emotional development, and is characterized by prominent neurobiological changes in the brain. The maturational processes that occur in brain regions responsible for cognitive control and reward seeking may underpin excessive consumption of palatable high fat and high sugar "junk" foods during adolescence. Recent studies have highlighted the negative impact of these foods on brain function, resulting in cognitive impairments and altered reward processing. The increased neuroplasticity during adolescence may render the brain vulnerable to the negative effects of these foods on cognition and behavior. In this review, we describe the mechanisms by which junk food diets influence neurodevelopment during adolescence. Diet can lead to alterations in dopamine-mediated reward signaling, and inhibitory neurotransmission controlled by γ-aminobutyric acid (GABA), two major neurotransmitter systems that are under construction across adolescence. We propose that poor dietary choices may derail the normal adolescent maturation process and influence neurodevelopmental trajectories, which can predispose individuals to dysregulated eating and impulsive behaviors. © 2017 Wiley Periodicals, Inc.

  13. Taxing junk food: applying the logic of the Henry tax review to food.

    Science.gov (United States)

    Bond, Molly E; Williams, Michael J; Crammond, Brad; Loff, Bebe

    2010-10-18

    The recent review of taxation in Australia - the Henry tax review - has recommended that the federal government increase the taxes already levied on tobacco and alcohol. Tobacco and alcohol taxes are put forward as the best way of reducing the social harms caused by the use and misuse of these substances. Junk foods have the same pattern of misuse and the same social costs as tobacco and alcohol. The Henry tax review rejects the idea of taxing fatty foods, and to date the government has not implemented a tax on junk food. We propose that a tax on junk food be implemented as a tool to reduce consumption and address the obesity epidemic.

  14. Konsumsi Junk Food dan Hipertensi pada Lansia di Kecamatan Kasihan, Bantul, Yogyakarta

    OpenAIRE

    Rantiningsih Sumarni; Edi Sampurno; Veriani Aprilia

    2015-01-01

    The risk of hypertension increases in line with a changes in modern lifestyle. Elderly tends to select food such as junk food with high calories, and fat, but low in fi ber and other nutrients. Junk food contains high amounts of sodium that can increase the volume of blood in the body, so make stronger heart blood pumps and cause the higher blood pressure (hypertension). The purpose of this study was to identify the relationship between junk food consumption and hypertension in elderly in Kasi...

  15. Paparan iklan junk food dan pola konsumsi junk food sebagai faktor risiko terjadinya obesitas pada anak sekolah dasar kota dan desa di Daerah Istimewa Yogyakarta

    Directory of Open Access Journals (Sweden)

    Esti Nurwanti

    2016-03-01

    Full Text Available ABSTRACTBackground: Increasing prevalence of obesity may be caused by junk food advertised while children are watching television.Preference for foods requested by the children is much infl uenced by junk food advertisement, so that it can affect calori intakeand correlates with obesity. Obesity in children can cause obesity during adulthood and may increase the risk of degenerativedisease, like diabetes and cardiovascular.Objective: To analyze the level of risk exposure to junk food advertising and junk food consumption on the incidence of obesityin primary school children in elementary school children at the area of Yogyakarta Municipality and District of Bantul.Method: This study was an observational study with case-control design. The study population was elementary school childrenin the City of Yogyakarta and Bantul Regency. Cases were elementary school children who were obese, while the controlswere children who were not obese and sat closest the cases regardless of age and sex. Number of subjects for each groupwere 244 (1:1. Obesity was defi ned as BMI / U>95th percentile curves NCHS/CDC. Sampling to fi nd obesity with probabilityproportional to size (PPS and sampling for cases and controls using random sampling techniques. Univariate analysis ofthe data using frequency distributions, bivariate analysis using Chi-square, and multivariate analysis using multiple logisticregression. Data were analyzed using STATA 11 program with a 95% signifi cance level and nutrisurvey.Result: Bivariate analysis using Chi Square shows the variables that infl uence the incidence of obesity, such as junkfood ads exposure (OR=1.70, 95%CI: 1.17-2.48, and p=0.004, junk food energy intake (OR=1.58, 95%CI:  1.08-2.32and p=0.01, intake of saturated fat junk food (OR=1.74, 95%CI: 1.18-2.56 and p=0.004, sodium intake of junk food(OR=1.83, 95%CI: 1.25-2.69 and p=0.001 and sex (OR=0.58, 95%CI: 0.40-0.85 and p= 0.0035. Multivariate analysiswith logistic

  16. Junk food seen at pediatric clinic visits: is it a problem?

    Science.gov (United States)

    Frazier, Johnnie P; Land, Megan; Hsieh, Pei-Hsuan; Barratt, Michelle S

    2014-04-01

    To document the prevalence of junk foods seen at clinic visits. A cross-sectional 23-item survey of observed food items were completed by medical staff using a convenience sample of families from June 2, 2011 to March 2, 2012. The study was conducted in pediatric clinics affiliated with the University of Texas Medical School at Houston. A convenience sample consisting of 738 families with children from 4 months to 16 years old presenting for visits were included in the study. Children exclusively breast and formula fed was excluded. Junk food was observed 20.9% at the clinic visits. Junk food was often seen at clinic visits. There was a trend toward higher body mass index in patients whose families had junk food at the visit.

  17. Factors Associated with Consuming Junk Food among Saudi Adults in Jeddah City.

    Science.gov (United States)

    Mandoura, Najlaa; Al-Raddadi, Rajaa; Abdulrashid, Ola; Shah, Hassan Bin Usman; Kassar, Sulaiman M; Adel Hawari, Abdul Rehman; Jahhaf, Jana M

    2017-12-31

    Introduction Junk food (JF) consumption trend is increasing in all parts of the world. The transition in lifestyle and dietary habits is leading to many non-communicable diseases. The objectives of this study are twofold: (1) To examine the prevalence of junk food consumption and factors associated with consuming junk food among Saudi adults in Jeddah; and (2) to compare the trends of junk food consumption among males and females in Jeddah. Methodology This cross-sectional study was conducted in five different Primary Health Care centers (PHCCs) of Jeddah working under Ministry of Health. The subjects were men (n = 146) and women (n = 254) aged 18-67 years visiting these centers. Structured validated close ended questionnaire was filled by all the participants. Data analysis was done using SPSS. Chi-square was applied to analyze the difference between male and female JF consumption and multivariate logistic regression analysis was done to examine the risk factors. Results Overall the JF consumption in subjects with mean age 33.69 ± 12.29 years was highly prevalent in both genders (86.5%); (men = 85.6% and women = 87.4%). Controlling for some demographic and socioeconomic variables, increased junk food consumption was independently associated with education (OR = 2.47, 95% CI: 1.088-5.605, p = 0.031), individuals who had limited time (OR = 3.82, 95% CI: 1.690-8.642, p junk food consumption among Saudi adults. Junk food has influence in the dietary patterns of Saudi adults and this trend is likely to rise. This growing widespread use of junk food is of concern which may cause obesity-related non-communicable diseases.

  18. Hubungan Konsumsi Junk Food dengan Status Gizi Lebih pada Siswa SD Pertiwi 2 Padang

    OpenAIRE

    Rizki Nur Amalia; Delmi Sulastri; Rima Semiarty

    2016-01-01

    AbstrakGizi lebih adalah keadaan tubuh seseorang yang mengalami berat badan berlebih karena kelebihan jumlah asupan energi yang disimpan dalam bentuk cadangan berupa lemak. Prevalensi gizi lebih pada anak di Indonesia mencapai 10,4. Salah satu faktor risiko terjadinya gizi lebih adalah kebiasaan mengonsumsi junk food. Tujuan penelitian ini adalah menentukan hubungan antara konsumsi junk food dengan status gizi lebih pada anak usia sekolah. Penelitian ini adalah penelitian analitik dengan ranc...

  19. Immature psychological defense mechanisms are associated with greater personal importance of junk food, alcohol, and television.

    Science.gov (United States)

    Costa, Rui Miguel; Brody, Stuart

    2013-10-30

    Immature psychological defense mechanisms are psychological processes that play an important role in suppressing emotional awareness and contribute to psychopathology. In addition, unhealthy food, television viewing, and alcohol consumption can be among the means to escape self-awareness. In contrast, engaging in, and responding fully to specifically penile-vaginal intercourse (PVI) is associated with indices of better emotional regulation, including less use of immature defense mechanisms. There was a lack of research on the association of immature defense mechanisms with personal importance of junk food, alcohol, television, PVI, and noncoital sex. In an online survey, 334 primarily Scottish women completed the Defense Style Questionnaire (DSQ-40), and rated the personal importance of junk food, alcohol, television, PVI, and noncoital sex. Immature defense mechanisms correlated with importance of junk food, alcohol, and television. Importance of PVI correlated with mature defenses, and less use of some component immature defenses. Importance of alcohol correlated with importance of junk food, television, and noncoital sex. Importance of junk food was correlated with importance of television and noncoital sex. The findings are discussed in terms of persons with poorer self-regulatory abilities having more interest in junk food, television, and alcohol, and less interest in PVI. © 2013 Elsevier Ireland Ltd. All rights reserved.

  20. Fatty acid analysis of Iranian junk food, dairy, and bakery products: Special attention to trans-fats

    OpenAIRE

    Nazari, Bahar; Asgary, Sedigheh; Azadbakht, Leila

    2012-01-01

    Background: Low attention to dairy product consumptions and high intake of junk foods and bakery products might be related to high prevalence of chronic diseases because of their fat content and fatty acid composition. Objective: In this study we investigated the kind and amount of fatty acid content in Iranian junk foods, dairy, and bakery products Materials and Methods: Some common brands of Iranian′s junk foods, dairy, and bakery products were chosen randomly from different supermarkets in...

  1. Assessing junk food consumption among Australian children: trends and associated characteristics from a cross-sectional study

    OpenAIRE

    S Boylan; L. L. Hardy; B. A. Drayton; A. Grunseit; S. Mihrshahi

    2017-01-01

    Abstract Background The ubiquitous supply of junk foods in our food environment has been partly blamed for the increased rates in overweight and obesity. However, consumption of these foods has generally been examined individually perhaps obscuring the true extent of their combined consumption and impact on health. An overall measure of children’s junk food consumption may prove useful in the development of child obesity prevention strategies. We describe the development of a children’s Junk ...

  2. Hubungan Konsumsi Junk Food dengan Status Gizi Lebih pada Siswa SD Pertiwi 2 Padang

    Directory of Open Access Journals (Sweden)

    Rizki Nur Amalia

    2016-01-01

    Full Text Available AbstrakGizi lebih adalah keadaan tubuh seseorang yang mengalami berat badan berlebih karena kelebihan jumlah asupan energi yang disimpan dalam bentuk cadangan berupa lemak. Prevalensi gizi lebih pada anak di Indonesia mencapai 10,4. Salah satu faktor risiko terjadinya gizi lebih adalah kebiasaan mengonsumsi junk food. Tujuan penelitian ini adalah menentukan hubungan antara konsumsi junk food dengan status gizi lebih pada anak usia sekolah. Penelitian ini adalah penelitian analitik dengan rancangan cross sectional terhadap populasi penelitian yaitu siswa kelas 1 – 5 di SD Pertiwi 2 Padang sebanyak 250 siswa. Teknik pengambilan data dilakukan dengan menggunakan kuesioner semi kuantitatif FFQ.  Status gizi ditentukan dengan pengukuran berat badan dan tinggi badan yang hasilnya dikategorikan menggunakan standar antropometri penilaian status gizi anak menurut Depkes Indonesia. Pada hasil penelitian didapatkan bahwa siswa yang memiliki status gizi lebih hanya 23,6% dengan rata – rata IMT 16,9±3,69. Rata – rata frekuensi konsumsi junk food 4,6±2,9 kali per hari dan rata – rata asupan energi junk food 1046,5±918,4 kkal per hari. Kesimpulan penelitian ini adalah terdapat hubungan yang bermakna antara konsumsi frekuensi konsumsi junk food dengan kejadian gizi lebih (p = 0,013 dan tidak terdapat hubungan yang bermakna antara asupan energi junk food dengan kejadian gizi lebih (p = 0,120.Kata kunci: gizi lebih, junk food, FFQ AbstractOverweight is a condition of an individual who suffer from excessive weight due to an excess of energy intake stored in fat tissue. Prevalence of overweight in children in Indonesia reaches 10,4 %. One of the risk factors contributing to this condition is consuming junk food. The objective of this study was to identify the relationship of junk food consumption and overweight in students. This research is an analytic study conducted in a cross sectional design using 250  students of class 1-5 in SD Pertiwi 2 Padang

  3. Junk science for sale Sham journals proliferating online.

    Science.gov (United States)

    Klyce, Walter; Feller, Edward

    2017-07-05

    A new danger threatens the integrity of scholarly publishing: predatory journals. Internet-only, "open-access" publishing is a valid way for researchers to reach the public without a paywall separating them. But, of thousands of open-access scientific journals today, as many as twenty-five percent are believed to be fake, existing only to make money by charging authors high processing fees. In sham journals, peer review is cursory or absent: as many as eighty to ninety percent of submitted manuscripts are accepted, many within days, without any editorial comment. Predatory journalism can be remarkably good at mimicking reputable publishers. Sham journals use names and logos that closely resemble those of legitimate journals, intentionally confusing site visitors. Untrustworthy publications have not received the widespread, damning publicity they deserve. If junk science is not confronted and eliminated, it will continue to tarnish and undermine ethical, open-access scholarly publishing. [Full article available at http://rimed.org/rimedicaljournal-2017-07.asp].

  4. Function of Junk: Pericentromeric Satellite DNA in Chromosome Maintenance.

    Science.gov (United States)

    Jagannathan, Madhav; Yamashita, Yukiko M

    2018-04-02

    Satellite DNAs are simple tandem repeats that exist at centromeric and pericentromeric regions on eukaryotic chromosomes. Unlike the centromeric satellite DNA that comprises the vast majority of natural centromeres, function(s) for the much more abundant pericentromeric satellite repeats are poorly understood. In fact, the lack of coding potential allied with rapid divergence of repeat sequences across eukaryotes has led to their dismissal as "junk DNA" or "selfish parasites." Although implicated in various biological processes, a conserved function for pericentromeric satellite DNA remains unidentified. We have addressed the role of satellite DNA through studying chromocenters, a cytological aggregation of pericentromeric satellite DNA from multiple chromosomes into DNA-dense nuclear foci. We have shown that multivalent satellite DNA-binding proteins cross-link pericentromeric satellite DNA on chromosomes into chromocenters. Disruption of chromocenters results in the formation of micronuclei, which arise by budding off the nucleus during interphase. We propose a model that satellite DNAs are critical chromosome elements that are recognized by satellite DNA-binding proteins and incorporated into chromocenters. We suggest that chromocenters function to preserve the entire chromosomal complement in a single nucleus, a fundamental and unquestioned feature of eukaryotic genomes. We speculate that the rapid divergence of satellite DNA sequences between closely related species results in discordant chromocenter function and may underlie speciation and hybrid incompatibility. © 2017 Jagannathan and Yamashita; Published by Cold Spring Harbor Laboratory Press.

  5. A maternal "junk-food" diet reduces sensitivity to the opioid antagonist naloxone in offspring postweaning.

    Science.gov (United States)

    Gugusheff, Jessica R; Ong, Zhi Yi; Muhlhausler, Beverly S

    2013-03-01

    Perinatal exposure to a maternal "junk-food" diet has been demonstrated to increase the preference for palatable diets in adult offspring. We aimed to determine whether this increased preference could be attributed to changes in μ-opioid receptor expression within the mesolimbic reward pathway. We report here that mRNA expression of the μ-opioid receptor in the ventral tegmental area (VTA) at weaning was 1.4-fold (males) and 1.9-fold (females) lower in offspring of junk-food (JF)-fed rat dams than in offspring of dams fed a standard rodent diet (control) (Pjunk-food diet results in early desensitization of the opioid system which may explain the increased preference for junk food in these offspring.

  6. Attitudinal Ambivalence as a Protective Factor Against Junk Food Advertisements: A Moderated Mediation Model of Behavioral Intention.

    Science.gov (United States)

    Ran, Weina; Yamamoto, Masahiro

    2015-08-01

    This study investigates the role of attitudinal ambivalence in moderating the effects of junk food advertisements on behavioral intentions by tapping different facets of this construct-felt ambivalence, potential ambivalence, and affective-cognitive ambivalence. Results based on an online survey of college students indicate that attention to junk food advertisements has an indirect positive effect on intentions to eat junk food through its positive effect on attitudes toward junk food. A moderated mediation model reveals that this indirect effect of junk food advertisements is weakened as respondents' levels of felt ambivalence increase. This moderating role is not observed for the measures of potential ambivalence and affective-cognitive ambivalence. Implications are discussed for health interventions.

  7. Pattern of access determines influence of junk food diet on cue sensitivity and palatability.

    Science.gov (United States)

    Kosheleff, Alisa R; Araki, Jingwen; Hsueh, Jennifer; Le, Andrew; Quizon, Kevin; Ostlund, Sean B; Maidment, Nigel T; Murphy, Niall P

    2018-04-01

    Like drug addiction, cues associated with palatable foods can trigger food-seeking, even when sated. However, whether susceptibility to the motivating influence of food-related cues is a predisposing factor in overeating or a consequence of poor diet is difficult to determine in humans. Using a rodent model, we explored whether a highly palatable 'junk food' diet impacts responses to reward-paired cues in a Pavlovian-to-instrumental transfer test, using sweetened condensed milk (SCM) as the reward. The hedonic impact of SCM consumption was also assessed by analyzing licking microstructure. To probe the effects of pattern and duration of junk food exposure, we provided rats with either regular chow ad libitum (controls) or chow plus access to junk food for either 2 or 24 h per day for 1, 3, or 6 weeks. We also examined how individual susceptibility to weight gain related to these measures. Rats provided 24 h access to the junk food diet were insensitive to the motivational effects of a SCM-paired cue when tested sated even though their hedonic experience upon reward consumption was similar to controls. In contrast, rats provided restricted, 2 h access to junk food exhibited a cue generalization phenotype under sated conditions, lever-pressing with increased vigor in response to both a SCM-paired cue, and a cue not previously paired with reward. Hedonic response was also significantly higher in these animals relative to controls. These data demonstrate that the pattern of junk food exposure differentially alters the hedonic impact of palatable foods and susceptibility to the motivating influence of cues in the environment to promote food-seeking actions when sated, which may be consequential for understanding overeating and obesity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Assessing junk food consumption among Australian children: trends and associated characteristics from a cross-sectional study

    Directory of Open Access Journals (Sweden)

    S Boylan

    2017-04-01

    Full Text Available Abstract Background The ubiquitous supply of junk foods in our food environment has been partly blamed for the increased rates in overweight and obesity. However, consumption of these foods has generally been examined individually perhaps obscuring the true extent of their combined consumption and impact on health. An overall measure of children’s junk food consumption may prove useful in the development of child obesity prevention strategies. We describe the development of a children’s Junk Food Intake Measure (JFIM to summarise temporal change in junk food consumption and examine the association between the JFIM and health-related behaviours. Methods Cross-sectional population surveillance survey of Australian children age 5–16 years collected in 2010 and 2015. Data were collected by questionnaire with parent’s proxy reporting for children in years K, 2 and 4 and children in years 6, 8 and 10 by self-report. Information on diet, screen-time and physical activity was collected using validated questionnaires. The JFIM comprised consumption of fried potato products, potato crisps/salty snacks, sweet and savoury biscuits/cakes/doughnuts, confectionary and, ice cream/ice blocks. Results A total of 7565 (missing = 493, 6.1% and 6944 (missing n = 611, 8.1% children had complete data on consumption of junk foods, in 2010 and 2015, respectively. The 2015 survey data showed that among students from high socio-economic status neighbourhoods, there were fewer high junk food consumers than low junk food consumers. Children from Middle Eastern cultural backgrounds had higher junk food consumption. High junk food consumers were more likely to consume take-away ≥3/week, eat dinner in front of the television, receive sweet rewards, be allowed to consume snacks anytime, have soft drinks available at home and a TV in their bedroom. There was a lower proportion of high junk food consumers in 2015 compared to 2010. Conclusion This is the first study

  9. Assessing junk food consumption among Australian children: trends and associated characteristics from a cross-sectional study.

    Science.gov (United States)

    Boylan, S; Hardy, L L; Drayton, B A; Grunseit, A; Mihrshahi, S

    2017-04-05

    The ubiquitous supply of junk foods in our food environment has been partly blamed for the increased rates in overweight and obesity. However, consumption of these foods has generally been examined individually perhaps obscuring the true extent of their combined consumption and impact on health. An overall measure of children's junk food consumption may prove useful in the development of child obesity prevention strategies. We describe the development of a children's Junk Food Intake Measure (JFIM) to summarise temporal change in junk food consumption and examine the association between the JFIM and health-related behaviours. Cross-sectional population surveillance survey of Australian children age 5-16 years collected in 2010 and 2015. Data were collected by questionnaire with parent's proxy reporting for children in years K, 2 and 4 and children in years 6, 8 and 10 by self-report. Information on diet, screen-time and physical activity was collected using validated questionnaires. The JFIM comprised consumption of fried potato products, potato crisps/salty snacks, sweet and savoury biscuits/cakes/doughnuts, confectionary and, ice cream/ice blocks. A total of 7565 (missing = 493, 6.1%) and 6944 (missing n = 611, 8.1%) children had complete data on consumption of junk foods, in 2010 and 2015, respectively. The 2015 survey data showed that among students from high socio-economic status neighbourhoods, there were fewer high junk food consumers than low junk food consumers. Children from Middle Eastern cultural backgrounds had higher junk food consumption. High junk food consumers were more likely to consume take-away ≥3/week, eat dinner in front of the television, receive sweet rewards, be allowed to consume snacks anytime, have soft drinks available at home and a TV in their bedroom. There was a lower proportion of high junk food consumers in 2015 compared to 2010. This is the first study to provide and examine a summary measure of overall junk food

  10. Food as Risk: How Eating Habits and Food Knowledge Affect Reactivity to Pictures of Junk and Healthy Foods.

    Science.gov (United States)

    Yegiyan, Narine S; Bailey, Rachel L

    2016-01-01

    This study explores how people respond to images of junk versus healthy food as a function of their eating habits and food knowledge. The experiment reported here proposed and tested the idea that those with unhealthy eating habits but highly knowledgeable about healthy eating would feel more positive and also more negative toward junk food images compared to images of healthy food because they may perceive them as risky--desirable but potentially harmful. The psychophysiological data collected from participants during their exposure to pictures of junk versus healthy food supported this idea. In addition, unhealthy eaters compared to healthy eaters with the same degree of food knowledge responded more positively to all food items. The findings are critical from a health communication perspective. Because unhealthy eaters produce stronger emotional responses to images of junk food, they are more likely to process information associated with junk food with more cognitive effort and scrutiny. Thus, when targeting this group and using images of junk food, it is important to combine these images with strong message claims and relevant arguments; otherwise, if the arguments are perceived as irrelevant or weak, the motivational activation associated with junk food itself may transfer into an increased desire to consume the unhealthy product.

  11. Comparing children's GPS tracks with geospatial proxies for exposure to junk food.

    Science.gov (United States)

    Sadler, Richard C; Gilliland, Jason A

    2015-01-01

    Various geospatial techniques have been employed to estimate children's exposure to environmental cardiometabolic risk factors, including junk food. But many studies uncritically rely on exposure proxies which differ greatly from actual exposure. Misrepresentation of exposure by researchers could lead to poor decisions and ineffective policymaking. This study conducts a GIS-based analysis of GPS tracks--'activity spaces'--and 21 proxies for activity spaces (e.g. buffers, container approaches) for a sample of 526 children (ages 9-14) in London, Ontario, Canada. These measures are combined with a validated food environment database (including fast food and convenience stores) to create a series of junk food exposure estimates and quantify the errors resulting from use of different proxy methods. Results indicate that exposure proxies consistently underestimate exposure to junk foods by as much as 68%. This underestimation is important to policy development because children are exposed to more junk food than estimated using typical methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Persistent junk solutions in time-domain modeling of extreme mass ratio binaries

    International Nuclear Information System (INIS)

    Field, Scott E.; Hesthaven, Jan S.; Lau, Stephen R.

    2010-01-01

    In the context of metric perturbation theory for nonspinning black holes, extreme mass ratio binary systems are described by distributionally forced master wave equations. Numerical solution of a master wave equation as an initial boundary value problem requires initial data. However, because the correct initial data for generic-orbit systems is unknown, specification of trivial initial data is a common choice, despite being inconsistent and resulting in a solution which is initially discontinuous in time. As is well known, this choice leads to a burst of junk radiation which eventually propagates off the computational domain. We observe another potential consequence of trivial initial data: development of a persistent spurious solution, here referred to as the Jost junk solution, which contaminates the physical solution for long times. This work studies the influence of both types of junk on metric perturbations, waveforms, and self-force measurements, and it demonstrates that smooth modified source terms mollify the Jost solution and reduce junk radiation. Our concluding section discusses the applicability of these observations to other numerical schemes and techniques used to solve distributionally forced master wave equations.

  13. 'Junk food' diet and childhood behavioural problems: results from the ALSPAC cohort.

    Science.gov (United States)

    Wiles, N J; Northstone, K; Emmett, P; Lewis, G

    2009-04-01

    To determine whether a 'junk food' diet at age 4(1/2) is associated with behavioural problems at age 7. Data on approximately 4000 children participating in the Avon Longitudinal Study of Parents and Children, a birth cohort recruited in Avon, UK in 1991/92 were used. Behavioural problems were measured at age 7 using the Strengths and Difficulties Questionnaire (SDQ; maternal completion). Total difficulties and scores for the five sub-scales (hyperactivity, conduct and peer problems, emotional symptoms and pro-social behaviour) were calculated. Principal components analysis of dietary data (frequency of consumption of 57 foods/drinks) collected at age 4(1/2) by maternal report was used to generate a 'junk food' factor. Data on confounders were available from questionnaires. A one standard deviation increase in 'junk food' intake at age 4(1/2) years was associated with increased hyperactivity at age 7 (odds ratio: 1.19; 95% confidence interval: 1.10, 1.29). This persisted after adjustment for confounders including intelligence quotient score (odds ratio: 1.13; 95% confidence interval: 1.01, 1.15). There was little evidence to support an association between 'junk food' intake and overall behavioural difficulties or other sub-scales of the SDQ. Children eating a diet high in 'junk food' in early childhood were more likely to be in the top 33% on the SDQ hyperactivity sub-scale at age 7. This may reflect a long-term nutritional imbalance, or differences in parenting style. This finding requires replication before it can provide an avenue for intervention.

  14. Junk food” diet and childhood behavioural problems: Results from the ALSPAC cohort

    Science.gov (United States)

    Wiles, Nicola J; Northstone, Kate; Emmett, Pauline; Lewis, Glyn

    2007-01-01

    Objective To determine whether a “junk food” diet at age 4½ is associated with behavioural problems at age 7. Subjects and Methods Data on approximately 4000 children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC), a birth cohort recruited in Avon, UK in 1991/92, were used. Behavioural problems were measured at age 7 using the Strengths & Difficulties Questionnaire (SDQ) (maternal completion). Total difficulties and scores for the 5 sub-scales (hyperactivity, conduct & peer problems, emotional symptoms, & prosocial behaviour) were calculated. Principal components analysis of dietary data (frequency of consumption of 57 foods/drinks) collected at age 4½ by maternal report was used to generate a “junk food” factor. Data on confounders were available from questionnaires. Results A one standard deviation increase in “junk food” intake at age 4½ years was associated with increased hyperactivity at age 7 (odds ratio: 1.19 (95% confidence interval: 1.10, 1.29)). This persisted after adjustment for confounders including IQ score (odds ratio: 1.13 (95% confidence interval: 1.01, 1.15)). There was little evidence to support an association between “junk food” intake and overall behavioural difficulties or other sub-scales of the SDQ. Conclusions Children eating a diet high in “junk food” in early childhood were more likely to be in the top 33% on the SDQ hyperactivity sub-scale at age 7. This may reflect a long-term nutritional imbalance, or differences in parenting style. This finding requires replication before it can provide an avenue for intervention. PMID:18059416

  15. The Correlation between Junk Food Consumption and Age of Menarche of Elementary School Student In Gedung Johor Medan

    Directory of Open Access Journals (Sweden)

    Surya Anita

    2018-01-01

    Full Text Available ABSTRACT Acceleration age of menarche, can increase the chances of endometrial hyperplasia. The incidence of uterine and breast cancer are associated with early menarche. Junk food is indicated as one of the triggers of early menarche. With observational-analytic research and case-control research design, it was conducted to determine the effect of junk food in early menarche at elementary school student. The population of the study was the 6th grade elementary school students who had been menstruated, yet the sample was chosen randomly. Data collected using questionnaires, also measuring weight and height, then analysed using chi-square. The results shows a relationship between junk food consumption with early menarche incidence (p = 0.021 and OR 1.889. This is due to the high consumption patterns of junk food/fast food in teenages. Affected by behavioral patterns of people who tend to choose practical food, easy to get and ready to eat.   ABSTRAK Percepatan usia menarche dapat memperbesar peluang terjadI hyperplasia endometrium. Insiden kanker uterus dan kanker payudara dihubungkan dengan menarche dini.  Junk food diindikasi sebagai salah satu pemicu menarche dini. Dengan penelitian observasional-analitik dan desain penelitian case-control, dilakukan untuk mengetahui pengaruh junk food pada menarche dini di usia SD. Populasi penelitian adalah siswi SD kelas VI yang sudah haid /belum, sampel dipilih secara random. Pengumpulan data menggunakan kuesioner kepada siswi, menimbang berat badan serta  mengukur tinggi badan. Analisis data menggunakan chi-square. Hasil penelitian bahwa ada hubungan konsumsi junk food dengan kejadian menarche dini (p=0,021 dan OR 1,889. Hal ini disebabkan Tingginya pola konsumsi junk food/fast food  pada remaja dipengaruhi oleh pola perilaku masyarakat yang cenderung memilih makanan praktis, mudah didapat dan siap saji.

  16. JUNK FOOD ASSOCIATION WITH THE MORPHOLOGICAL CHANGES OF GASTRITIS-A CROSS-SECTIONAL STUDY AMONG RURAL CHILDREN OF MELMARUVATHUR

    Directory of Open Access Journals (Sweden)

    Sumathi S

    2016-09-01

    Full Text Available BACKGROUND AND AIM Junk food consumption is common among children that have much adverse effect on the growth of the children and health. This study is aimed to assess the correlation of frequency of junk food intake with the morphological changes of gastric antral biopsies in dyspeptic children. MATERIALS AND METHODS This cross-sectional observational study was carried out in Melmaruvathur Medical College Hospital, Melmaruvathur, during the year 2014-2015. The participants were dyspeptic children between 10-15 years of age. They were interviewed using various junk food frequency questionnaires and antral biopsy was taken for histopathological assessment. The morphological changes of gastric antral biopsies were recorded and their association with junk food was analysed. RESULTS Out of 37 children studied, the predominant age group affected were between 5-10 years (56.8% with female predominance (67%. Among the frequency, daily usage of junk food constitutes 57% of cases and the remaining 43% were taking intermittently. Biscuits, chocolates, packed chips were regularly used by daily user and bottled drinks, ice cream were used intermittently. Morphological assessment of gastritis showed significant association of junk food intake with increased intensity of mononuclear cell infiltration with a P value of 0.05, presence of Helicobacter pylori with a P value of 0.02 and presence of regenerative atypical changes with a P value of 0.006. CONCLUSION There is a significant association between the junk food intake and the severity of gastritis. The intensity of inflammatory changes, regenerative atypical glands and Helicobacter pylori presence and load were more among those having the habit of daily junk food intake than those taking intermittently.

  17. JUNK FOOD ASSOCIATION WITH THE MORPHOLOGICAL CHANGES OF GASTRITIS-A CROSS-SECTIONAL STUDY AMONG RURAL CHILDREN OF MELMARUVATHUR

    OpenAIRE

    Sumathi S; Padma K

    2016-01-01

    BACKGROUND AND AIM Junk food consumption is common among children that have much adverse effect on the growth of the children and health. This study is aimed to assess the correlation of frequency of junk food intake with the morphological changes of gastric antral biopsies in dyspeptic children. MATERIALS AND METHODS This cross-sectional observational study was carried out in Melmaruvathur Medical College Hospital, Melmaruvathur, during the year 2014-2015. The participants ...

  18. Formation of the market of high-bond (junk bonds in the United States in 1970–1980 years

    Directory of Open Access Journals (Sweden)

    Moshenskyi S.Z.

    2017-03-01

    Full Text Available Market of high-yield bonds (also known as «junk bonds» began to emerge in the US in the mid-1970s and was associated with the activities of «junk bond king» Michael Milken from Drexel investment company. Junk bonds emitents are small and newly established companies which cannot get a high credit rating. Emission of high-yield (8–10 % bond was their only chance to find its place in the financial market. Michael Milken realized the potential of these bonds, which, in fact, were often quite reliable securities, and started organizing their emissions by selling junk bonds to Savings and Loan Associations and other investors. In the 1980 issue of such bonds used for aggressive corporate takeovers, which supplied the capital from junk bonds market. Some of takeovers carried out in violation of laws that led to the arrest of Michael Milken, Drexel bankruptcy and the collapse of the entire junk bonds market.

  19. Junk Food Consumption and Effects on Growth Status among Children Aged 6-24 Months in Mashhad, Northeastern Iran

    Directory of Open Access Journals (Sweden)

    Rahim Vakili

    2015-08-01

    Full Text Available Introduction Junk food, due to the lack of vitamins, minerals and trace amounts of energy and protein, there is the risk that the child's stomach filled and by reducing her/his appetite, reduce the chance of nutritious foods. So it is necessary to determine the relationship between using of junk food with growth rate in children. Materials and Methods This cross-sectional descriptive-analytic study was conducted on 300 mothers and their babies , who were referring to 10 selected Mashhad health-care centers for monitoring their 6-24 months children. Participants were selected by cluster and simple random sampling and valid and reliable   questionnaire was used to collect data. Data were analyzed by descriptive- analytic statistics and using SPSS version 16. Results In growth chart, 86.7 percent of children showed appropriate growth, 10.3 percent had delayed growth and 3 percent had horizontal growth curve. In 11.3 percent of families, the junk food has been used for children regularly, 44.7 percent did not believe in these snacks and 44 percent of mothers sometimes used this junk food for their children. Results showed the statistical correlation between junk food consumption and  growth status of children was significant, so children whom haven’t had junk food, have grown more favorable than the other kids (P

  20. Legal and Administrative Feasibility of a Federal Junk Food and Sugar-Sweetened Beverage Tax to Improve Diet.

    Science.gov (United States)

    Pomeranz, Jennifer L; Wilde, Parke; Huang, Yue; Micha, Renata; Mozaffarian, Dariush

    2018-02-01

    To evaluate legal and administrative feasibility of a federal "junk" food (including sugar-sweetened beverages [SSBs]) tax to improve diet. To assess food definitions and administration models, we systematically searched (1) PubMed (through May 15, 2017) for articles defining foods subject to taxes, and legal and legislative databases as well as online for (2) US federal, state, and tribal junk food tax bills and laws (January 1, 2012-February 28, 2017); SSB taxes (January 1, 2014-February 28, 2017); and international junk food tax laws (as of February 28, 2017); and (3) federal taxing mechanisms and administrative methods (as of February 28, 2017). Articles recommend taxing foods by product category, broad nutrient criteria, specific nutrients or calories, or a combination. US junk food tax bills (n = 6) and laws (n = 3), international junk food laws (n = 2), and US SSB taxes (n = 10) support taxing foods using category-based (n = 8), nutrient-based (n = 1), or combination (n = 12) approaches. Federal taxing mechanisms (particularly manufacturer excise taxes on alcohol) and administrative methods provide informative models. From legal and administrative perspectives, a federal junk food tax appears feasible based on product categories or combination category-plus-nutrient approaches, using a manufacturer excise tax, with additional support for sugar and graduated tax strategies.

  1. Sino-Japanese Interaction via Chinese Junks in the Edo Period

    OpenAIRE

    MATSUURA, Akira

    2010-01-01

    To maintain its policy of national isolation during the Edo period, Japan restricted contact with the outside world to Dutch merchant ships and Chinese junks at the Japanese port of Nagasaki. Sino-Japanese interaction consisted not only of trade in goods, but also of cultural and scholarly exchanges. This paper will examine how this unofficial trade affected both Japan and China from a cultural perspective.

  2. Implantation of the NC ISO 9001 in the Radioactivity measurement service in junks of CPHR

    International Nuclear Information System (INIS)

    Ramos V, E.O.; Dominguez L, O.; Capote F, E.; Fernandez G, I.M.; Caveda R, C.; Alonso A, D.; Barroso P, I.; Madraso M, S.

    2006-01-01

    In the last years in the international environment, radiological incidents have been reported, due to the presence of radioactive materials in the junk, that have implied the adoption of measures in matter of radiological safety, to avoid affectations in the public and the environment, as well as in the international trade. The establishment of the radiological control of junk during it commercialization requires of the implantation of a quality management program. In such sense, the present work exposes the experience of our institution in the design and organization of a service for the radioactivity measurement in junks based on a quality administration system based on the requirements of the quality standards ISO 9001:2000, ISO/IEC 17050 and ISO/IEC 17025:2000. In coherence with the postulates defined in the institutional strategy related to the implantation of a total quality system and the international demands on this matter. To such ends the processes that compose the service were identified, the corresponding and implemented procedures were elaborated, the registrations associated to the same one, being worked in the design of a quality assurance program that allowed the evaluation of the conformity of the product and the customer. (Author)

  3. A maternal "junk food" diet in pregnancy and lactation promotes nonalcoholic Fatty liver disease in rat offspring.

    Science.gov (United States)

    Bayol, Stéphanie A; Simbi, Bigboy H; Fowkes, Robert C; Stickland, Neil C

    2010-04-01

    With rising obesity rates, nonalcoholic fatty liver disease is predicted to become the main cause of chronic liver disease in the next decades. Rising obesity prevalence is attributed to changes in dietary habits with increased consumption of palatable junk foods, but maternal malnutrition also contributes to obesity in progeny. This study examines whether a maternal junk food diet predisposes offspring to nonalcoholic fatty liver disease. The 144 rat offspring were fed either a balanced chow diet alone or with palatable junk foods rich in energy, fat, sugar, and/or salt during gestation, lactation, and/or after weaning up to the end of adolescence. Offspring fed junk food throughout the study exhibited exacerbated hepatic steatosis, hepatocyte ballooning, and oxidative stress response compared with offspring given free access to junk food after weaning only. These offspring also displayed sex differences in their hepatic molecular metabolic adaptation to diet-induced obesity with increased expression of genes associated with insulin sensitivity, de novo lipogenesis, lipid oxidation, and antiinflammatory properties in males, whereas the gene expression profile in females was indicative of hepatic insulin resistance. Hepatic inflammation and fibrosis were not detected indicating that offspring had not developed severe steatohepatitis by the end of adolescence. Hepatic steatosis and increased oxidative stress response also occurred in offspring born to junk food-fed mothers switched to a balanced chow diet from weaning, highlighting a degree of irreversibility. This study shows that a maternal junk food diet in pregnancy and lactation contributes to the development of nonalcoholic fatty liver disease in offspring.

  4. A Maternal “Junk Food” Diet in Pregnancy and Lactation Promotes Nonalcoholic Fatty Liver Disease in Rat Offspring

    Science.gov (United States)

    Bayol, Stéphanie A.; Simbi, Bigboy H.; Fowkes, Robert C.; Stickland, Neil C.

    2010-01-01

    With rising obesity rates, nonalcoholic fatty liver disease is predicted to become the main cause of chronic liver disease in the next decades. Rising obesity prevalence is attributed to changes in dietary habits with increased consumption of palatable junk foods, but maternal malnutrition also contributes to obesity in progeny. This study examines whether a maternal junk food diet predisposes offspring to nonalcoholic fatty liver disease. The 144 rat offspring were fed either a balanced chow diet alone or with palatable junk foods rich in energy, fat, sugar, and/or salt during gestation, lactation, and/or after weaning up to the end of adolescence. Offspring fed junk food throughout the study exhibited exacerbated hepatic steatosis, hepatocyte ballooning, and oxidative stress response compared with offspring given free access to junk food after weaning only. These offspring also displayed sex differences in their hepatic molecular metabolic adaptation to diet-induced obesity with increased expression of genes associated with insulin sensitivity, de novo lipogenesis, lipid oxidation, and antiinflammatory properties in males, whereas the gene expression profile in females was indicative of hepatic insulin resistance. Hepatic inflammation and fibrosis were not detected indicating that offspring had not developed severe steatohepatitis by the end of adolescence. Hepatic steatosis and increased oxidative stress response also occurred in offspring born to junk food-fed mothers switched to a balanced chow diet from weaning, highlighting a degree of irreversibility. This study shows that a maternal junk food diet in pregnancy and lactation contributes to the development of nonalcoholic fatty liver disease in offspring. PMID:20207831

  5. Offspring from mothers fed a ‘junk food’ diet in pregnancy and lactation exhibit exacerbated adiposity that is more pronounced in females

    Science.gov (United States)

    Bayol, S A; Simbi, B H; Bertrand, J A; Stickland, N C

    2008-01-01

    We have shown previously that a maternal junk food diet during pregnancy and lactation plays a role in predisposing offspring to obesity. Here we show that rat offspring born to mothers fed the same junk food diet rich in fat, sugar and salt develop exacerbated adiposity accompanied by raised circulating glucose, insulin, triglyceride and/or cholesterol by the end of adolescence (10 weeks postpartum) compared with offspring also given free access to junk food from weaning but whose mothers were exclusively fed a balanced chow diet in pregnancy and lactation. Results also showed that offspring from mothers fed the junk food diet in pregnancy and lactation, and which were then switched to a balanced chow diet from weaning, exhibited increased perirenal fat pad mass relative to body weight and adipocyte hypertrophy compared with offspring which were never exposed to the junk food diet. This study shows that the increased adiposity was more enhanced in female than male offspring and gene expression analyses showed raised insulin-like growth factor-1 (IGF-1), insulin receptor substrate (IRS)-1, vascular endothelial growth factor (VEGF)-A, peroxisome proliferator-activated receptor-γ (PPARγ), leptin, adiponectin, adipsin, lipoprotein lipase (LPL), Glut 1, Glut 3, but not Glut 4 mRNA expression in females fed the junk food diet throughout the study compared with females never given access to junk food. Changes in gene expression were not as marked in male offspring with only IRS-1, VEGF-A, Glut 4 and LPL being up-regulated in those fed the junk food diet throughout the study compared with males never given access to junk food. This study therefore shows that a maternal junk food diet promotes adiposity in offspring and the earlier onset of hyperglycemia, hyperinsulinemia and/or hyperlipidemia. Male and female offspring also display a different metabolic, cellular and molecular response to junk-food-diet-induced adiposity. PMID:18467362

  6. Offspring from mothers fed a 'junk food' diet in pregnancy and lactation exhibit exacerbated adiposity that is more pronounced in females.

    Science.gov (United States)

    Bayol, S A; Simbi, B H; Bertrand, J A; Stickland, N C

    2008-07-01

    We have shown previously that a maternal junk food diet during pregnancy and lactation plays a role in predisposing offspring to obesity. Here we show that rat offspring born to mothers fed the same junk food diet rich in fat, sugar and salt develop exacerbated adiposity accompanied by raised circulating glucose, insulin, triglyceride and/or cholesterol by the end of adolescence (10 weeks postpartum) compared with offspring also given free access to junk food from weaning but whose mothers were exclusively fed a balanced chow diet in pregnancy and lactation. Results also showed that offspring from mothers fed the junk food diet in pregnancy and lactation, and which were then switched to a balanced chow diet from weaning, exhibited increased perirenal fat pad mass relative to body weight and adipocyte hypertrophy compared with offspring which were never exposed to the junk food diet. This study shows that the increased adiposity was more enhanced in female than male offspring and gene expression analyses showed raised insulin-like growth factor-1 (IGF-1), insulin receptor substrate (IRS)-1, vascular endothelial growth factor (VEGF)-A, peroxisome proliferator-activated receptor-gamma (PPARgamma), leptin, adiponectin, adipsin, lipoprotein lipase (LPL), Glut 1, Glut 3, but not Glut 4 mRNA expression in females fed the junk food diet throughout the study compared with females never given access to junk food. Changes in gene expression were not as marked in male offspring with only IRS-1, VEGF-A, Glut 4 and LPL being up-regulated in those fed the junk food diet throughout the study compared with males never given access to junk food. This study therefore shows that a maternal junk food diet promotes adiposity in offspring and the earlier onset of hyperglycemia, hyperinsulinemia and/or hyperlipidemia. Male and female offspring also display a different metabolic, cellular and molecular response to junk-food-diet-induced adiposity.

  7. Time bomb or hidden treasure? Characteristics of junk TVs and of the US households who store them

    Energy Technology Data Exchange (ETDEWEB)

    Milovantseva, Natalia, E-mail: nmilovan@uci.edu [School of Social Ecology, University of California, Irvine, CA 92697 (United States); Saphores, Jean-Daniel, E-mail: saphores@uci.edu [Civil and Environmental Engineering, Economics, and Planning, Policy, and Design Departments, University of California, Irvine, CA 92697 (United States)

    2013-03-15

    Highlights: ► US households are storing 84.1 million broken or obsolete (junk) TVs. ► They represent 2.12 million metric tons of scrap. ► The value of these materials is approximately $21 per TV. ► Our count models characterize US households who store junk TVs. ► Our results are useful for designing more effective TV recycling programs. - Abstract: Within the growing stockpile of electronic waste (e-waste), TVs are especially of concern in the US because of their number (which is known imprecisely), their low recycling rate, and their material content: cathode ray tube televisions contain lead, and both rear projection and flat panel displays contain mercury, in addition to other potentially toxic materials. Based on a unique dataset from a 2010 survey, our count models show that pro-environmental behavior, age, education, household size, marital status, gender of the head of household, dwelling type, and geographic location are statistically significant variables for explaining the number of broken or obsolete (junk) TVs stored by US households. We also estimate that they are storing approximately 84.1 million junk TVs, which represents 40 pounds of scrap per household. Materials in each of these junk TVs are worth $21 on average at January 2012 materials prices, which sets an upper bound on collecting and recycling costs. This information should be helpful for developing more effective recycling strategies for TVs in the e-waste stream.

  8. Fatty acid analysis of Iranian junk food, dairy, and bakery products: Special attention to trans-fats

    Directory of Open Access Journals (Sweden)

    Bahar Nazari

    2012-01-01

    Full Text Available Background: Low attention to dairy product consumptions and high intake of junk foods and bakery products might be related to high prevalence of chronic diseases because of their fat content and fatty acid composition. Objective: In this study we investigated the kind and amount of fatty acid content in Iranian junk foods, dairy, and bakery products Materials and Methods: Some common brands of Iranian′s junk foods, dairy, and bakery products were chosen randomly from different supermarkets in Iran. The amount of 10 g sample was considered for fatty acid analysis by gas chromatography equipment with flam ionization detector. Results: In this study stearic acid (C18:0 and palmitic (C16:0 acid have the highest amount among other saturated fatty acids in all groups. In junk foods and bakery products, the most common trans-fatty acid (TFA is elaidic acid (C18:1 9t with ranging from 2.4% to 18.5% and in dairy products vaccinic acid (C18:1 11t has the high level of TFAs among others (2.1% to 11.5%. Conclusion: The amount of TFAs in Iranian junk foods and bakery products was in a high level.

  9. Fatty acid analysis of Iranian junk food, dairy, and bakery products: Special attention to trans-fats.

    Science.gov (United States)

    Nazari, Bahar; Asgary, Sedigheh; Azadbakht, Leila

    2012-10-01

    Low attention to dairy product consumptions and high intake of junk foods and bakery products might be related to high prevalence of chronic diseases because of their fat content and fatty acid composition. In this study we investigated the kind and amount of fatty acid content in Iranian junk foods, dairy, and bakery products. Some common brands of Iranian's junk foods, dairy, and bakery products were chosen randomly from different supermarkets in Iran. The amount of 10 g sample was considered for fatty acid analysis by gas chromatography equipment with flam ionization detector. In this study stearic acid (C18:0) and palmitic (C16:0) acid have the highest amount among other saturated fatty acids in all groups. In junk foods and bakery products, the most common trans-fatty acid (TFA) is elaidic acid (C18:1 9t) with ranging from 2.4% to 18.5% and in dairy products vaccinic acid (C18:1 11t) has the high level of TFAs among others (2.1% to 11.5%). The amount of TFAs in Iranian junk foods and bakery products was in a high level.

  10. Evidence that a maternal "junk food" diet during pregnancy and lactation can reduce muscle force in offspring.

    Science.gov (United States)

    Bayol, Stéphanie A; Macharia, Raymond; Farrington, Samantha J; Simbi, Bigboy H; Stickland, Neil C

    2009-02-01

    Obesity is a multi-factorial condition generally attributed to an unbalanced diet and lack of exercise. Recent evidence suggests that maternal malnutrition during pregnancy and lactation can also contribute to the development of obesity in offspring. We have developed an animal model in rats to examine the effects of maternal overeating on a westernized "junk food" diet using palatable processed foods rich in fat, sugar and salt designed for human consumption. Using this model, we have shown that such a maternal diet can promote overeating and a greater preference for junk food in offspring at the end of adolescence. The maternal junk food diet also promoted adiposity and muscle atrophy at weaning. Impaired muscle development may permanently affect the function of this tissue including its ability to generate force. The aim of this study is to determine whether a maternal junk food diet can impair muscle force generation in offspring. Twitch and tetanic tensions were measured in offspring fed either chow alone (C) or with a junk food diet (J) during gestation, lactation and/or post-weaning up to the end of adolescence such that three groups of offspring were used, namely the CCC, JJC and JJJ groups. We show that adult offspring from mothers fed the junk food diet in pregnancy and lactation display reduced muscle force (both specific twitch and tetanic tensions) regardless of the post-weaning diet compared with offspring from mothers fed a balanced diet. Maternal malnutrition can influence muscle force production in offspring which may affect an individual's ability to exercise and thereby combat obesity.

  11. Maternal "junk food" diet during pregnancy as a predictor of high birthweight: findings from the healthy beginnings trial.

    Science.gov (United States)

    Wen, Li Ming; Simpson, Judy M; Rissel, Chris; Baur, Louise A

    2013-03-01

    A high infant birthweight is associated with future risk of a range of adverse health consequences. This study sought to determine whether maternal "junk food" diet (energy-dense, nutrient-poor) predicts high birthweight in first-time mothers in southwest Sydney, Australia. A community-based longitudinal study was conducted with a total of 368 first-time mothers and their newborns. Information about maternal "junk food" diet, including high consumption of soft drink, fast food, and/or processed meat and chips, and self-reported prepregnant weight and height of first-time mothers was collected by a face-to-face interview with mothers between 24 and 34 weeks of pregnancy. Birthweight was measured in hospital and reported by the mother, together with gestational age, when the baby was 6 months old. Logistic regression modeling was used to determine the factors predicting birthweight greater than 4.0 kg. Eleven percent of newborns weighed more than 4.0 kg (12% boys, 9% girls). Compared with mothers who had a "junk food" diet, mothers who had not consumed "junk food" during pregnancy were significantly less likely to have a newborn weighing more than 4.0 kg, with adjusted odds ratio (AOR) 0.36, 95 percent confidence interval (CI) 0.14-0.91, p = 0.03, after adjusting for maternal weight status and gestational age. Compared with healthy and underweight mothers, overweight or obese mothers were more likely to have a newborn weighing more than 4.0 kg (AOR overweight 3.03, 95% CI 1.35-6.80; obese 3.79, 95% CI 1.41-10.25) after allowing for "junk food" diet and gestational age. Maternal "junk food" diet during pregnancy and prepregnant overweight and obesity were independent predictors of high infant birthweight. Early childhood obesity interventions should consider addressing these factors. © 2013, Copyright the Authors Journal compilation © 2013, Wiley Periodicals, Inc.

  12. CONSUMPTION OF JUNK FOOD; A CAUSE OF DENTAL CARIES AMONG EARLY CHILDHOOD

    OpenAIRE

    Dr. Nirmal Kaur; Miss Neha Qumar; Nisha Gangwar

    2016-01-01

    Unfortunately, today’s world has been adapted to a system of consumption of junk foods which has several adverse effects on health. Thus the study was conducted to find out the food habits and problems associated with fast food consumption amongst the children of 3-6 years of age of Pilibhit District of UP. The result showed that cent per cent respondents consumed candies followed by potato chips, chocolate, ice-cream and soft drink, as 93.33 %, 90 %, 96.66 %, and 66.66 % respectively. Beside...

  13. On causal roles and selected effects: our genome is mostly junk.

    Science.gov (United States)

    Doolittle, W Ford; Brunet, Tyler D P

    2017-12-05

    The idea that much of our genome is irrelevant to fitness-is not the product of positive natural selection at the organismal level-remains viable. Claims to the contrary, and specifically that the notion of "junk DNA" should be abandoned, are based on conflating meanings of the word "function". Recent estimates suggest that perhaps 90% of our DNA, though biochemically active, does not contribute to fitness in any sequence-dependent way, and possibly in no way at all. Comparisons to vertebrates with much larger and smaller genomes (the lungfish and the pufferfish) strongly align with such a conclusion, as they have done for the last half-century.

  14. "Nutritional Wastelands": Vending Machines, Fast Food Outlets, and the Fight over Junk Food in Canadian Schools.

    Science.gov (United States)

    Gidney, Catherine

    2015-01-01

    In light of a growing obesity crisis among children and concern about junk food in schools, this article investigates the attempt by food and beverage companies to gain entry into Canadian schools. Focusing in particular on the introduction of fast-food franchises in cafeterias and on school boards' secret exclusivity deals with soft drink manufacturers in the 1990s, it examines how and why this process occurred, public reactions to it, and government responses. Placing this phenomenon within a larger pattern of commercialization in North American schools, it argues that long-lasting reforms require government intervention and enforcement.

  15. Microbial diversity and prevalence of foodborne pathogens in cheap and junk foods consumed by primary schoolchildren.

    Science.gov (United States)

    Kim, M J; Kim, S A; Kang, Y S; Hwang, I G; Rhee, M S

    2013-07-01

    Aerobic plate counts (APC), coliforms, Bacillus cereus, Escherichia coli and eight foodborne pathogens were tested in 1008 cheap and junk foods, including candies, dried cakes, chewing gum, chocolate, dried and seasoned seafood, ice cream, and sugary foods. APCs were positive for 342 samples (33·9%), and the majority of the counts were 2-3 log CFU g(-1) or ml(-1) (average: 1·10 log CFU g(-1) or ml(-1) ). Most samples (97·3%) contained no coliforms (average: 0·07 log CFU g(-1) or ml(-1) ). Bacillus cereus was detected in 68 samples (average: 0·14 log CFU g(-1) or ml(-1) ). Escherichia coli and Listeria monocytogenes were detected in 6 and 1 samples, respectively, whereas other foodborne pathogens were not isolated. The highest bacterial counts were associated with dried and seasoned seafood products and dried cakes, suggesting that appropriate regulations of these food types should be considered. Cheap and junk foods were produced mainly in developing countries, but there were no significant differences in the bacterial counts among different countries of origin. The presence of foodborne pathogens may pose a risk for children. These results suggest that there is cause for deeper concern about the safety of these foods and that effective countermeasures should be established to improve their microbiological safety. Food safety is especially important for children, but only limited information is available about the microbiological quality of cheap and junk foods that are consumed frequently by primary schoolchildren (e.g. dried cakes, candies and chocolates). The present study investigated the microbial quality of cheap and junk foods, and our results indicate that these foods are a potential health risk for children, therefore, deeper concern about the safety of these foods and effective countermeasures should be established to improve their microbiological safety. The present study may contribute to the development of an appropriate child food

  16. Junk Food Consumption and Effects on Growth Status among Children Aged 6-24 Months in Mashhad, Northeastern Iran

    OpenAIRE

    Rahim Vakili; Mohammad Ali Kiani; Masumeh Saeidi; Bibi Leila Hoseini; Mansoure Alipour Anbarani

    2015-01-01

    Introduction Junk food, due to the lack of vitamins, minerals and trace amounts of energy and protein, there is the risk that the child's stomach filled and by reducing her/his appetite, reduce the chance of nutritious foods. So it is necessary to determine the relationship between using of junk food with growth rate in children. Materials and Methods This cross-sectional descriptive-analytic study was conducted on 300 mothers and their babies , who were referring to 10 selected Mashhad healt...

  17. JUNK FOOD CONSUMPTION PATTERN AND OBESITY AMONG SCHOOL GOING CHILDREN IN AN URBAN FIELD PRACTICE AREA: A CROSS SECTIONAL STUDY

    Directory of Open Access Journals (Sweden)

    Vidya

    2015-03-01

    Full Text Available BACKGROUND: Junk food simply means an empty calorie food; it lacks in micronutrients such as vitamins, minerals, or amino acids, and fibre but has high energy (calories. During school - age years, children begin to establish habits for eating and exercise that stick w ith them for their entire lives. If children establish healthy habits, their risk for developing many chronic diseases will be greatly decreased. The family, friends, schools, and community resources in a child’s environment reinforce lifestyle habits rega rding diet and activity. OBJECTIVES: To study the fast food consumptions pattern and fast food preferences among the school going children (9 - 13yrs and some of the determinants related to fast food consumption . STUDY SETTING: Department of Community Medic ine in an Urban field practice area of Rajarajeswari Medical College & Hospital, Bangalore. STUDY DESIGN: Cross - sectional study. STUDY DURATION: Three months duration ( Oct – Dec 2014. STUDY POPULATION: school students studying in V th standard to X th standar d. SAMPLE SIZE : The selected school had a strength of 200 students. Hence complete enumeration of the students was considered for this study. DATA COLLECTION : by using pre - structured questionnaire by interview method. The variables included were socio - demographic profile, measurement of height, weight and questions related to junk food consumption and its patterns. DATA ANALYSIS: using statistics software SPSS 20. Mean and standard deviation was calculated for anthropometric measurements. Test of significance for proportions was done by Chi - square test. RESULTS: Among 200 study subjects, 107 were male (53.5% and 93 females (46.5%. Majority of the students wer e in the age group of 12 - 15 years ( 66% and 9 - 11 years ( 34%. Snacks (41%, Fast food (25.50%, soft drinks (17.50% and candies (16% were the favourite junk foods among the study subjects. Taste and time factors, watching television while consuming

  18. The effects of television advertisements for junk food versus nutritious food on children's food attitudes and preferences.

    Science.gov (United States)

    Dixon, Helen G; Scully, Maree L; Wakefield, Melanie A; White, Victoria M; Crawford, David A

    2007-10-01

    Television (TV) food advertising has attracted criticism for its potential role in promoting unhealthy dietary practices among children. Content analyses indicate junk food advertising is prevalent on Australian children's TV; healthy eating is rarely promoted. This paper presents (a) a cross-sectional survey examining associations between children's regular TV viewing habits and their food-related attitudes and behaviour; and (b) an experiment assessing the impact of varying combinations of TV advertisements (ads) for unhealthy and healthy foods on children's dietary knowledge, attitudes and intentions. The experimental conditions simulated possible models for regulating food ads on children's TV. Participants were 919 grade five and six students from schools in Melbourne, Australia. The survey showed that heavier TV use and more frequent commercial TV viewing were independently associated with more positive attitudes toward junk food; heavier TV use was also independently associated with higher reported junk food consumption. The experiment found that ads for nutritious foods promote selected positive attitudes and beliefs concerning these foods. Findings are discussed in light of methodological issues in media effects research and their implications for policy and practice. It is concluded that changing the food advertising environment on children's TV to one where nutritious foods are promoted and junk foods are relatively unrepresented would help to normalize and reinforce healthy eating.

  19. The Partially Flipped Classroom: The Effects of Flipping a Module on "Junk Science" in a Large Methods Course

    Science.gov (United States)

    Burgoyne, Stephanie; Eaton, Judy

    2018-01-01

    Flipped classrooms are gaining popularity, especially in psychology statistics courses. However, not all courses lend themselves to a fully flipped design, and some instructors might not want to commit to flipping every class. We tested the effectiveness of flipping just one component (a module on junk science) of a large methods course. We…

  20. Radiological control of the junk exports in Cuba; Control radiologico de las exportaciones de chatarra en Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez L, O; Capote F, E; Carrazana G, J A; Zerquera, J T; Ramos V, O; Alonso A, D; Fernandez, I M; Caveda R, C A; Madrazo M, S; Barroso P, I [CPHR, Calle 20 No. 4113 e/41 y 47, Playa, C.P. 11300, A.P. 6195, C.P. 10600 La Habana (Cuba)

    2006-07-01

    Even when in Cuba a strict control exists on the radiation sources that enter to the country to be used in the different applications, it can be given the case that sources or contaminated materials that never were under this control due fundamentally to that entered to the country before the same one existed, appear in the junk that is marketed. In our country it is effective the Combined Resolution CITMA-MINCEX dated on April, 2002 that settles down the necessity and obligation that has all that manipulates, imports, exports or process junk of carrying out it a radiological control. From April, 2002 making use of a minimum of resources, an own methodology, a properly qualified personnel and the support of a credited laboratory by the ISO 17025 standard, the radioactivity measurement service in junk belonging to the Center of Protection and Hygiene of the Radiations (CPHR), it has reduced the risks that sources or contaminated materials are found in the junk that is exported in the main exporter companies of this line in Cuba avoiding possible radiological emergency situations that affect the population and the environment. (Author)

  1. Consumption of junk foods by school-aged children in rural Himachal Pradesh, India.

    Science.gov (United States)

    Gupta, Aakriti; Kapil, Umesh; Singh, Gajendra

    2018-01-01

    There has been an increase in the consumption of junk food (JF) among school-aged children (SAC) possibly leading to obesity and diet-related diseases among them. We do not have evidence on consumption of JF in rural areas; hence, we conducted a study to assess the consumption of JF by SAC in rural, Himachal Pradesh. A total of 425 children in the age group of 12-18 years studying in 30 government schools (clusters) were included. The clusters were selected using population proportionate to size sampling methodology. We found high prevalence (36%) of consumption of JF among SAC during the last 24 h. Efforts should be taken to reduce the consumption of JF by promotion of healthy dietary habits and educating children about the ill effects of JF.

  2. Energy drinks, caffeine, junk food, breakfast, depression and academic attainment of secondary school students.

    Science.gov (United States)

    Smith, Andrew P; Richards, Gareth

    2018-06-01

    Energy drinks are widely consumed, and concerns have been raised about possible negative outcomes. The aim of the present research was to examine associations between consumption of energy drinks, caffeine and junk food, and academic attainment in a sample of UK secondary school students. A total of 3071 students agreed to participate in the study; 2677 completed the survey on one occasion (52.4% female, 47.6% male; approximately 20% of the sample from each school year) and 1660 (49.6% female, 50.4% male) completed the survey a second time, approximately six months later. The academic attainment measure was based on Key Stage 3 and Key Stage 4 grades for Maths and English. In the cross-sectional analyses, logistic regressions showed that consumption of energy drinks was associated with a greater likelihood of being in the low academic achievement group. This was not found for other sources of caffeine. The effect of energy drinks was still significant when demographic, academic and health/lifestyle variables were covaried. However, inclusion of an unhealthy diet variable (junk food) removed the significant effect of energy drinks. Similar observations were made in the longitudinal study, with the poorer attainment of those who consumed energy drinks reflecting breakfast omission and depression. The present findings indicate that consumption of energy drinks is associated with an increased likelihood of poor academic attainment that reflects energy drink consumption being part of an unhealthy diet or being associated with skipping breakfast rather than a more specific effect, such as being a source of caffeine. Although the current study extends previous research by utilising a longitudinal design, intervention studies are now required to better answer questions relating to causality and direction of effect.

  3. Spam and scams:China’s netizens wallow in junk mail But producers of spam could soon face the government’s wrath

    Institute of Scientific and Technical Information of China (English)

    MARK GODFREY

    2004-01-01

    <正> Email has revolutionised communication. It’s also becoming an increasingly effective channel for targeted marketing by companies with something to sell. But junk emails - more commonly known as

  4. State but not District Nutrition Policies Are Associated with Less Junk Food in Vending Machines and School Stores in US Public Schools

    Science.gov (United States)

    KUBIK, MARTHA Y.; WALL, MELANIE; SHEN, LIJUAN; NANNEY, MARILYN S.; NELSON, TOBEN F.; LASKA, MELISSA N.; STORY, MARY

    2012-01-01

    Background Policy that targets the school food environment has been advanced as one way to increase the availability of healthy food at schools and healthy food choice by students. Although both state- and district-level policy initiatives have focused on school nutrition standards, it remains to be seen whether these policies translate into healthy food practices at the school level, where student behavior will be impacted. Objective To examine whether state- and district-level nutrition policies addressing junk food in school vending machines and school stores were associated with less junk food in school vending machines and school stores. Junk food was defined as foods and beverages with low nutrient density that provide calories primarily through fats and added sugars. Design A cross-sectional study design was used to assess self-report data collected by computer-assisted telephone interviews or self-administered mail questionnaires from state-, district-, and school-level respondents participating in the School Health Policies and Programs Study 2006. The School Health Policies and Programs Study, administered every 6 years since 1994 by the Centers for Disease Control and Prevention, is considered the largest, most comprehensive assessment of school health policies and programs in the United States. Subjects/setting A nationally representative sample (n = 563) of public elementary, middle, and high schools was studied. Statistical analysis Logistic regression adjusted for school characteristics, sampling weights, and clustering was used to analyze data. Policies were assessed for strength (required, recommended, neither required nor recommended prohibiting junk food) and whether strength was similar for school vending machines and school stores. Results School vending machines and school stores were more prevalent in high schools (93%) than middle (84%) and elementary (30%) schools. For state policies, elementary schools that required prohibiting junk food

  5. State but not district nutrition policies are associated with less junk food in vending machines and school stores in US public schools.

    Science.gov (United States)

    Kubik, Martha Y; Wall, Melanie; Shen, Lijuan; Nanney, Marilyn S; Nelson, Toben F; Laska, Melissa N; Story, Mary

    2010-07-01

    Policy that targets the school food environment has been advanced as one way to increase the availability of healthy food at schools and healthy food choice by students. Although both state- and district-level policy initiatives have focused on school nutrition standards, it remains to be seen whether these policies translate into healthy food practices at the school level, where student behavior will be impacted. To examine whether state- and district-level nutrition policies addressing junk food in school vending machines and school stores were associated with less junk food in school vending machines and school stores. Junk food was defined as foods and beverages with low nutrient density that provide calories primarily through fats and added sugars. A cross-sectional study design was used to assess self-report data collected by computer-assisted telephone interviews or self-administered mail questionnaires from state-, district-, and school-level respondents participating in the School Health Policies and Programs Study 2006. The School Health Policies and Programs Study, administered every 6 years since 1994 by the Centers for Disease Control and Prevention, is considered the largest, most comprehensive assessment of school health policies and programs in the United States. A nationally representative sample (n=563) of public elementary, middle, and high schools was studied. Logistic regression adjusted for school characteristics, sampling weights, and clustering was used to analyze data. Policies were assessed for strength (required, recommended, neither required nor recommended prohibiting junk food) and whether strength was similar for school vending machines and school stores. School vending machines and school stores were more prevalent in high schools (93%) than middle (84%) and elementary (30%) schools. For state policies, elementary schools that required prohibiting junk food in school vending machines and school stores offered less junk food than

  6. Early Childhood Obesity Risk Factors: Socioeconomic Adversity, Family Dysfunction, Offspring Distress, and Junk Food Self-Medication.

    Science.gov (United States)

    Hemmingsson, Erik

    2018-06-01

    To explore the sequence and interaction of infancy and early childhood risk factors, particularly relating to disturbances in the social environment, and how the consequences of such exposures can promote weight gain and obesity. This review will argue that socioeconomic adversity is a key upstream catalyst that sets the stage for critical midstream risk factors such as family strain and dysfunction, offspring insecurity, stress, emotional turmoil, low self-esteem, and poor mental health. These midstream risk factors, particularly stress and emotional turmoil, create a more or less perfect foil for calorie-dense junk food self-medication and subtle addiction, to alleviate uncomfortable psychological and emotional states. Disturbances in the social environment during infancy and early childhood appear to play a critical role in weight gain and obesity, through such mechanisms as insecurity, stress, and emotional turmoil, eventually leading to junk food self-medication and subtle addiction.

  7. Exploring why junk foods are 'essential' foods and how culturally tailored recommendations improved feeding in Egyptian children.

    Science.gov (United States)

    Kavle, Justine A; Mehanna, Sohair; Saleh, Gulsen; Fouad, Mervat A; Ramzy, Magda; Hamed, Doaa; Hassan, Mohamed; Khan, Ghada; Galloway, Rae

    2015-07-01

    In Egypt, the double burden of malnutrition and rising overweight and obesity in adults mirrors the transition to westernized diets and a growing reliance on energy-dense, low-nutrient foods. This study utilized the trials of improved practices (TIPs) methodology to gain an understanding of the cultural beliefs and perceptions related to feeding practices of infants and young children 0-23 months of age and used this information to work in tandem with 150 mothers to implement feasible solutions to feeding problems in Lower and Upper Egypt. The study triangulated in-depth interviews (IDIs) with mothers participating in TIPs, with IDIs with 40 health providers, 40 fathers and 40 grandmothers to gain an understanding of the influence and importance of the role of other caretakers and health providers in supporting these feeding practices. Study findings reveal high consumption of junk foods among toddlers, increasing in age and peaking at 12-23 months of age. Sponge cakes and sugary biscuits are not perceived as harmful and considered 'ideal' common complementary foods. Junk foods and beverages often compensate for trivial amounts of food given. Mothers are cautious about introducing nutritious foods to young children because of fears of illness and inability to digest food. Although challenges in feeding nutritious foods exist, mothers were able to substitute junk foods with locally available and affordable foods. Future programming should build upon cultural considerations learned in TIPs to address sustainable, meaningful changes in infant and young child feeding to reduce junk foods and increase dietary quality, quantity and frequency. © 2014 The Authors. Maternal & Child Nutrition published by John Wiley & Sons Ltd.

  8. Evaluating the performance of unhealthy junk food consumption based on health belief model in elementary school girls

    Directory of Open Access Journals (Sweden)

    Azam Fathi

    2017-06-01

    Full Text Available Abstract Background and objective: Nowadays, due to changes in eating patterns, the worthless junk foods are replaced useful food among children. This study aimed to evaluate the performance of unhealthy junk food consumption based on health belief model in elementary school girls Methods: Cross-sectional study Descriptive-analytic type of multi-stage sampling (208 samples was carried out in 2016. The survey instrument was a questionnaire valid and reliable based on the Health Belief Model (70 items. Data was analyzed by SPSS software according to statistical tests of significance level of 0.05. Results: Results showed that students of sensitivity (49% and relatively high efficacy (53/8%, perceived benefits (73/1% and better social protection (68/3% had. The results showed that among all the health belief model structures with yield (junk food intake significantly correlated. Also significant differences in parental education and sensitivity, perceived severity, self-efficacy, social support and yield (p<0/05. Conclusion: The results of this study showed that students from relatively favorable sensitivity and self-efficacy, perceived benefits and social protection in the field of unhealthy snacks were good. Also a significant relationship between structural and non-use study results showed unhealthy snacks but because of the importance of unhealthy snacks and unhealthy snack consumption among school children and the complications of the health belief model in predicting nutritional behaviors suggest that this model used as a framework for school feeding programs. Paper Type: Research Article.

  9. 'Traffic-light' nutrition labelling and 'junk-food' tax: a modelled comparison of cost-effectiveness for obesity prevention.

    Science.gov (United States)

    Sacks, G; Veerman, J L; Moodie, M; Swinburn, B

    2011-07-01

    Cost-effectiveness analyses are important tools in efforts to prioritise interventions for obesity prevention. Modelling facilitates evaluation of multiple scenarios with varying assumptions. This study compares the cost-effectiveness of conservative scenarios for two commonly proposed policy-based interventions: front-of-pack 'traffic-light' nutrition labelling (traffic-light labelling) and a tax on unhealthy foods ('junk-food' tax). For traffic-light labelling, estimates of changes in energy intake were based on an assumed 10% shift in consumption towards healthier options in four food categories (breakfast cereals, pastries, sausages and preprepared meals) in 10% of adults. For the 'junk-food' tax, price elasticities were used to estimate a change in energy intake in response to a 10% price increase in seven food categories (including soft drinks, confectionery and snack foods). Changes in population weight and body mass index by sex were then estimated based on these changes in population energy intake, along with subsequent impacts on disability-adjusted life years (DALYs). Associated resource use was measured and costed using pathway analysis, based on a health sector perspective (with some industry costs included). Costs and health outcomes were discounted at 3%. The cost-effectiveness of each intervention was modelled for the 2003 Australian adult population. Both interventions resulted in reduced mean weight (traffic-light labelling: 1.3 kg (95% uncertainty interval (UI): 1.2; 1.4); 'junk-food' tax: 1.6 kg (95% UI: 1.5; 1.7)); and DALYs averted (traffic-light labelling: 45,100 (95% UI: 37,700; 60,100); 'junk-food' tax: 559,000 (95% UI: 459,500; 676,000)). Cost outlays were AUD81 million (95% UI: 44.7; 108.0) for traffic-light labelling and AUD18 million (95% UI: 14.4; 21.6) for 'junk-food' tax. Cost-effectiveness analysis showed both interventions were 'dominant' (effective and cost-saving). Policy-based population-wide interventions such as traffic

  10. A junk-food hypothesis for gannets feeding on fishery waste

    Science.gov (United States)

    Grémillet, David; Pichegru, Lorien; Kuntz, Grégoire; Woakes, Anthony G; Wilkinson, Sarah; Crawford, Robert J.M; Ryan, Peter G

    2008-01-01

    Worldwide fisheries generate large volumes of fishery waste and it is often assumed that this additional food is beneficial to populations of marine top-predators. We challenge this concept via a detailed study of foraging Cape gannets Morus capensis and of their feeding environment in the Benguela upwelling zone. The natural prey of Cape gannets (pelagic fishes) is depleted and birds now feed extensively on fishery wastes. These are beneficial to non-breeding birds, which show reduced feeding effort and high survival. By contrast, breeding gannets double their diving effort in an attempt to provision their chicks predominantly with high-quality, live pelagic fishes. Owing to a scarcity of this resource, they fail and most chicks die. Our study supports the junk-food hypothesis for Cape gannets since it shows that non-breeding birds can survive when complementing their diet with fishery wastes, but that they struggle to reproduce if live prey is scarce. This is due to the negative impact of low-quality fishery wastes on the growth patterns of gannet chicks. Marine management policies should not assume that fishery waste is generally beneficial to scavenging seabirds and that an abundance of this artificial resource will automatically inflate their populations. PMID:18270155

  11. More apples fewer chips? the effect of school fruit schemes on the consumption of junk food.

    Science.gov (United States)

    Brunello, Giorgio; De Paola, Maria; Labartino, Giovanna

    2014-10-01

    Using Italian data, we evaluate the effects on the consumption of unhealthy snacks of a European Union-wide campaign providing fruit and vegetables to school children and promoting healthy diet habits. We use scanner data of supermarket sales in the city of Rome. Using a difference-in-difference approach, we compare the sales of these snacks before and after the campaign in supermarkets located within a 500 m radius of schools that participated to the program (the treated group) and in supermarkets located outside that radius (control group). We find that the campaign has been effective in reducing the increase in the sales of unhealthy snacks in treated stores - relative to control stores - only in the case of regular stores, which tend to locate in the wealthier areas of Rome. No effect is found, instead, for discount stores, where people with a higher risk of developing obesity are more likely to shop. Our results suggest that the European School Fruit campaign has restrained the consumption of junk food in the sub-group of the population (wealthier families) who is less likely to be exposed to overweight and obesity problems, but has not been effective at all for the sub-group more at risk. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. [Study on factors related to top 10 junk food consumption at 8 to 16 years of age, in Haidian District of Beijing].

    Science.gov (United States)

    Zhu, Shu-ping; Ding, Yue-jiang; Lu, Xiang-feng; Wang, Hong-wei; Yang, Mu; Wang, Jian-xiu; Chao, Xiao-dong; Zhao, Zhen

    2008-08-01

    To study the current situation of ten types of junk food consumption (assessed by World Health Organization) among children and adolescent as well as the contributing factors in Haidian District, Beijing so as to provide evidence for developing preventive and control measures and interventions. A questionnaire survey was conducted to investigate the consumption of ten types of junk food practices in 1019 children and adolescent aged 8-16 years in Beijing Haidian District. One month prior to the study, 97.50% of the children and adolescent had eaten at least one type of junk food and 15.88% of them had eaten all types of them. Rates on having eaten deep fried food, pickled food, processed meat products, biscuits, coke or alike drinks, convenience/fast food, canned food, dried or preserved fruit, cold and sweet food, barbecue food etc. appeared to be 70.43%, 60.14%, 79.72%, 64.24%, 69.63%, 78.72%, 42.16%, 51.95%, 68.13%, 60.14% respectively. The rate on eaten more than once a day of these ten types were 26.95%, 36.88%, 34.84%, 32.97%, 27.40%, 28.18%, 37.91%, 26.15%, 37.39%, 22.10% respectively. The rates for "do not like" and "dislike" these ten types junk food were 10.96%, 27.42%, 7.08%, 12.11%, 6.56%, 6.59%, 17.80%, 13.59%, 3.42%, 5.19% respectively. Most of the children and adolescent ate junk food mainly during breakfast at home. Most of the surveyed children and adolescent did not have correct idea on nutrition of junk food. They received the information of junk food mainly from sources as advertisement on TV (67.95%), mother (9.02%), newspaper or magazines (6.71%). Many factors, such as individual factors (including physiological and psychological situations), social factors, family factors and the characteristics of food contributed to the eating junk food practices of children and adolescent. Eating junk food is a popular event among children and adolescent in Beijing Haidian District. Education strategies on nutrition should be developed and launched in

  13. Children's understanding of the selling versus persuasive intent of junk food advertising: implications for regulation.

    Science.gov (United States)

    Carter, Owen B J; Patterson, Lisa J; Donovan, Robert J; Ewing, Michael T; Roberts, Clare M

    2011-03-01

    Evidence suggests that until 8 years of age most children are cognitively incapable of appreciating the commercial purpose of television advertising and are particularly vulnerable to its persuasive techniques. After this age most children begin to describe the 'selling' intent of advertising and it is widely assumed this equips them with sufficient cognitive defences to protect against advertisers' persuasion attempts. However, much of the previous literature has been criticised for failing to differentiate between children's awareness of 'selling' versus 'persuasive' intent, the latter representing a more sophisticated understanding and superior cognitive defence. Unfortunately there is little literature to suggest at what age awareness of 'persuasive intent' emerges; our aim was to address this important issue. Children (n = 594) were recruited from each grade from Pre-primary (4-5 years) to Grade 7 (11-12 years) from ten primary schools in Perth, Western Australia and exposed to a McDonald's television advertisement. Understanding the purpose of television advertising was assessed both nonverbally (picture indication) and verbally (small discussion groups of 3-4), with particular distinction made between selling versus persuasive intent. Consistent with previous literature, a majority of children described the 'selling' intent of television advertising by 7-8 years both nonverbally and verbally, increasing to 90% by 11-12 years. Awareness of 'persuasive' intent emerged slowly as a function of age but even by our oldest age-group was only 40%. Vulnerability to television advertising may persist until children are far older than previously thought. These findings have important implications regarding the debate surrounding regulation of junk food (and other) advertising aimed at children. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Ribosomal RNA Genes Contribute to the Formation of Pseudogenes and Junk DNA in the Human Genome.

    Science.gov (United States)

    Robicheau, Brent M; Susko, Edward; Harrigan, Amye M; Snyder, Marlene

    2017-02-01

    Approximately 35% of the human genome can be identified as sequence devoid of a selected-effect function, and not derived from transposable elements or repeated sequences. We provide evidence supporting a known origin for a fraction of this sequence. We show that: 1) highly degraded, but near full length, ribosomal DNA (rDNA) units, including both 45S and Intergenic Spacer (IGS), can be found at multiple sites in the human genome on chromosomes without rDNA arrays, 2) that these rDNA sequences have a propensity for being centromere proximal, and 3) that sequence at all human functional rDNA array ends is divergent from canonical rDNA to the point that it is pseudogenic. We also show that small sequence strings of rDNA (from 45S + IGS) can be found distributed throughout the genome and are identifiable as an "rDNA-like signal", representing 0.26% of the q-arm of HSA21 and ∼2% of the total sequence of other regions tested. The size of sequence strings found in the rDNA-like signal intergrade into the size of sequence strings that make up the full-length degrading rDNA units found scattered throughout the genome. We conclude that the displaced and degrading rDNA sequences are likely of a similar origin but represent different stages in their evolution towards random sequence. Collectively, our data suggests that over vast evolutionary time, rDNA arrays contribute to the production of junk DNA. The concept that the production of rDNA pseudogenes is a by-product of concerted evolution represents a previously under-appreciated process; we demonstrate here its importance. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  15. 'Treats', 'sometimes foods', 'junk': a qualitative study exploring 'extra foods' with parents of young children.

    Science.gov (United States)

    Petrunoff, Nicholas A; Wilkenfeld, Rachel L; King, Lesley A; Flood, Victoria M

    2014-05-01

    The present study investigated parents' understanding and approaches to providing energy-dense and nutrient-poor 'extra foods' to pre-school children and explored variation between parents of low and high socio-economic status in relation to these issues. We conducted thirteen focus groups. Data were subject to framework analysis. Child-care centres in distinctly socially disadvantaged and socially advantaged areas. Eighty-eight parents of children aged 3-5 years. The three most common terms parents identified to describe foods that are not 'everyday foods' were 'treats', 'sometimes foods' and 'junk'. Parents' perceptions regarding what influences them in providing food to their children included seven sub-themes: (i) the influence of the child; (ii) food-related parenting practices; (iii) health considerations; (iv) food costs and convenience; (v) external factors perceived as influencing their child; (vi) factors related to child care; and (vii) social influences and occasions. Parents' decision-making processes regarding provision of 'extra foods' related to moderation and balance. Parents generally expressed the position that as long as a child is eating healthy foods, then treats are appropriate; and for many parents, this might apply frequently. All groups described the health of their child as an influence, but parents in low socio-economic groups were more likely to describe immediate concerns (dental health, behaviour) in relation to avoiding sugar-dense food or drink. The belief that provision of 'extra foods' can be frequent as long as children are eating a healthy balance of foods is factored into parents' decision making. Challenging this belief may be important for reducing the consumption of 'extra foods' by young children.

  16. Using GPS and activity tracking to reveal the influence of adolescents' food environment exposure on junk food purchasing.

    Science.gov (United States)

    Sadler, Richard C; Clark, Andrew F; Wilk, Piotr; O'Connor, Colleen; Gilliland, Jason A

    2016-06-09

    This study examines the influence of adolescents' exposure to unhealthy food outlets on junk food purchasing during trips between home and school, with particular attention to how exposure and purchasing differ according to child's biological sex, mode of transportation, and direction to or from school. Between 2010 and 2013, students (n = 654) aged 9-13 years from 25 schools in London and Middlesex County, ON, completed a socio-demographic survey and an activity diary (to identify food purchases), and were observed via a global positioning system for 2 weeks (to track routes for trips to/from school). Spatial data on routes and purchase data were integrated with a validated food outlet database in a geographic information system, and exposure was measured as the minutes a child spent within 50 m of an unhealthy food outlet (i.e., fast food restaurants, variety stores). For trips involving junk food exposure (n = 4588), multilevel logistic regression was used to assess the relationship between exposure and purchasing. Multilevel analyses indicated that adolescents' duration of exposure to unhealthy food outlets between home and school had a significant effect on the likelihood of junk food purchasing. This relationship remained significant when the data were stratified by sex (female/male), trip direction (to/from school) and travel mode (active/car), with the exception of adolescents who travelled by bus. Policies and programs that mitigate the concentration of unhealthy food outlets close to schools are critical for encouraging healthy eating behaviours among children and reducing diet-related health issues such as obesity.

  17. Eating 'Junk-Food' Produces Rapid and Long-Lasting Increases in NAc CP-AMPA Receptors: Implications for Enhanced Cue-Induced Motivation and Food Addiction.

    Science.gov (United States)

    Oginsky, Max F; Goforth, Paulette B; Nobile, Cameron W; Lopez-Santiago, Luis F; Ferrario, Carrie R

    2016-12-01

    Urges to eat are influenced by stimuli in the environment that are associated with food (food cues). Obese people are more sensitive to food cues, reporting stronger craving and consuming larger portions after food cue exposure. The nucleus accumbens (NAc) mediates cue-triggered motivational responses, and activations in the NAc triggered by food cues are stronger in people who are susceptible to obesity. This has led to the idea that alterations in NAc function similar to those underlying drug addiction may contribute to obesity, particularly in obesity-susceptible individuals. Motivational responses are mediated in part by NAc AMPA receptor (AMPAR) transmission, and recent work shows that cue-triggered motivation is enhanced in obesity-susceptible rats after 'junk-food' diet consumption. Therefore, here we determined whether NAc AMPAR expression and function is increased by 'junk-food' diet consumption in obesity-susceptible vs -resistant populations using both outbred and selectively bred models of susceptibility. In addition, cocaine-induced locomotor activity was used as a general 'read out' of mesolimbic function after 'junk-food' consumption. We found a sensitized locomotor response to cocaine in rats that gained weight on a 'junk-food' diet, consistent with greater responsivity of mesolimbic circuits in obesity-susceptible groups. In addition, eating 'junk-food' increased NAc calcium-permeable-AMPAR (CP-AMPAR) function only in obesity-susceptible rats. This increase occurred rapidly, persisted for weeks after 'junk-food' consumption ceased, and preceded the development of obesity. These data are considered in light of enhanced cue-triggered motivation and striatal function in obesity-susceptible rats and the role of NAc CP-AMPARs in enhanced motivation and addiction.

  18. Eating ‘Junk-Food' Produces Rapid and Long-Lasting Increases in NAc CP-AMPA Receptors: Implications for Enhanced Cue-Induced Motivation and Food Addiction

    Science.gov (United States)

    Oginsky, Max F; Goforth, Paulette B; Nobile, Cameron W; Lopez-Santiago, Luis F; Ferrario, Carrie R

    2016-01-01

    Urges to eat are influenced by stimuli in the environment that are associated with food (food cues). Obese people are more sensitive to food cues, reporting stronger craving and consuming larger portions after food cue exposure. The nucleus accumbens (NAc) mediates cue-triggered motivational responses, and activations in the NAc triggered by food cues are stronger in people who are susceptible to obesity. This has led to the idea that alterations in NAc function similar to those underlying drug addiction may contribute to obesity, particularly in obesity-susceptible individuals. Motivational responses are mediated in part by NAc AMPA receptor (AMPAR) transmission, and recent work shows that cue-triggered motivation is enhanced in obesity-susceptible rats after ‘junk-food' diet consumption. Therefore, here we determined whether NAc AMPAR expression and function is increased by ‘junk-food' diet consumption in obesity-susceptible vs -resistant populations using both outbred and selectively bred models of susceptibility. In addition, cocaine-induced locomotor activity was used as a general ‘read out' of mesolimbic function after ‘junk-food' consumption. We found a sensitized locomotor response to cocaine in rats that gained weight on a ‘junk-food' diet, consistent with greater responsivity of mesolimbic circuits in obesity-susceptible groups. In addition, eating ‘junk-food' increased NAc calcium-permeable-AMPAR (CP-AMPAR) function only in obesity-susceptible rats. This increase occurred rapidly, persisted for weeks after ‘junk-food' consumption ceased, and preceded the development of obesity. These data are considered in light of enhanced cue-triggered motivation and striatal function in obesity-susceptible rats and the role of NAc CP-AMPARs in enhanced motivation and addiction. PMID:27383008

  19. Association between junk food consumption and mental health in a national sample of Iranian children and adolescents: the CASPIAN-IV study.

    Science.gov (United States)

    Zahedi, Hoda; Kelishadi, Roya; Heshmat, Ramin; Motlagh, Mohammad Esmaeil; Ranjbar, Shirin Hasani; Ardalan, Gelayol; Payab, Moloud; Chinian, Mohammad; Asayesh, Hamid; Larijani, Bagher; Qorbani, Mostafa

    2014-01-01

    The consumption of high energy and low nutritional content foods, which are known as junk foods, has increased. The aim of this study was to evaluate the association between junk food intake and mental health in a national sample of Iranian children and adolescents. Data were obtained from a surveillance system entitled CASPIAN-IV (Childhood and Adolescence Surveillance and Prevention of Adult Non communicable Disease) study of school students, ages 6 to 18 y in Iran. The students and their parents completed two sets of reliable questionnaires obtained from Global School Health Survey translated to Persian. The student questionnaire comprised several questions such as psychiatric distress (worry, depression, confusion, insomnia, anxiety, aggression, and worthless) and violent behaviors (physical fighting, being a victim, and bullying). The junk foods consisted of sweets, sweetened beverages, fast foods, and salty snacks. In the sample of 13 486 children and adolescents, the frequency of junk food consumption was significantly associated with psychiatric distress (P junk foods (P 0.05). Additionally, the results of logistic regression showed that daily consumption of sweetened beverages and snacks significantly increased the odds of self-reported psychiatric distress. Also, daily consumption of salty snacks was significantly associated with violent behavior, including physical fighting (odds ratio [OR], 1.39; 95% confidence interval [CI], 1.21-1.60), being a victim (OR, 1.19; 95% CI, 1.04-1.37), and bullying (OR, 1.55; 95% CI, 1.32-1.82). Junk food consumption may increase the risk for psychiatric distress and violent behaviors in children and adolescents. Improvement of eating habits toward healthier diets may be an effective approach for improving mental health. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. The Effect of nutrition education on knowledge, attitude, and performance about junk food consumption among students of female primary schools

    Science.gov (United States)

    Vardanjani, Ali Esmaeili; Reisi, Mahnoush; Javadzade, Homamodin; Pour, Zabihollah Gharli; Tavassoli, Elahe

    2015-01-01

    Background: Undoubtedly, proper nutrition has important role in safeguarding the individual from many diseases, especially chronic ones, and increasing ones physical and intellectual efficiency. Considering the importance of nutrition education to school-age kids, this research was done with the purpose of determining the effect of nutrition education on the knowledge, attitude, and performance of female students at primary school about junk food consumption. Materials and Methods: This is an experimental intervention study in Shahr-e-kord city about the reduction of junk foods consumption in 2011. Seventy-two primary girl students were randomly divided into 2 groups, experimental (36) and controls (36). Before of the educational program, self-administrative questionnaire and FFQ (Food Frequency Questionnaire) questionnaire were filled out for both the groups. The self-administrative questionnaire was completed 3 times (before, immediately, and 2 months after education), and FFQ questionnaire was completed 2 times (before and 2 months after education) by students. After pre-test, 4 educational session classes in experimental group were performed. Finally, data were collected and analyzed by SPSS 16 computer software. Results: Demographic variables of the studied population in 2 groups were similar. Before intervention, there were no significant differences regarding the knowledge, attitude, and performance in 2 groups (P > 0/05). After intervention, there were significant differences in the levels of knowledge, attitude, and performance between experimental and control groups (P effective on increasing or improving the knowledge, attitude, and performance of the students. PMID:26430680

  1. Deep Investigation of Arabidopsis thaliana Junk DNA Reveals a Continuum between Repetitive Elements and Genomic Dark Matter

    Science.gov (United States)

    Maumus, Florian; Quesneville, Hadi

    2014-01-01

    Eukaryotic genomes contain highly variable amounts of DNA with no apparent function. This so-called junk DNA is composed of two components: repeated and repeat-derived sequences (together referred to as the repeatome), and non-annotated sequences also known as genomic dark matter. Because of their high duplication rates as compared to other genomic features, transposable elements are predominant contributors to the repeatome and the products of their decay is thought to be a major source of genomic dark matter. Determining the origin and composition of junk DNA is thus important to help understanding genome evolution as well as host biology. In this study, we have used a combination of tools enabling to show that the repeatome from the small and reducing A. thaliana genome is significantly larger than previously thought. Furthermore, we present the concepts and results from a series of innovative approaches suggesting that a significant amount of the A. thaliana dark matter is of repetitive origin. As a tentative standard for the community, we propose a deep compendium annotation of the A. thaliana repeatome that may help addressing farther genome evolution as well as transcriptional and epigenetic regulation in this model plant. PMID:24709859

  2. A Solution to the C-Value Paradox and the Function of Junk DNA: The Genome Balance Hypothesis.

    Science.gov (United States)

    Freeling, Michael; Xu, Jie; Woodhouse, Margaret; Lisch, Damon

    2015-06-01

    The Genome Balance Hypothesis originated from a recent study that provided a mechanism for the phenomenon of genome dominance in ancient polyploids: unique 24nt RNA coverage near genes is greater in genes on the recessive subgenome irrespective of differences in gene expression. 24nt RNAs target transposons. Transposon position effects are now hypothesized to balance the expression of networked genes and provide spring-like tension between pericentromeric heterochromatin and microtubules. The balance (coordination) of gene expression and centromere movement is under selection. Our hypothesis states that this balance can be maintained by many or few transposons about equally well. We explain known balanced distributions of junk DNA within genomes and between subgenomes in allopolyploids (and our hypothesis passes "the onion test" for any so-called solution to the C-value paradox). Importantly, when the allotetraploid maize chromosomes delete redundant genes, their nearby transposons are also lost; this result is explained if transposons near genes function. The Genome Balance Hypothesis is hypothetical because the position effect mechanisms implicated are not proved to apply to all junk DNA, and the continuous nature of the centromeric and gene position effects have not yet been studied as a single phenomenon. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  3. Testing the junk-food hypothesis on marine birds: Effects of prey type on growth and development

    Science.gov (United States)

    Romano, Marc D.; Piatt, John F.; Roby, D.D.

    2006-01-01

    The junk-food hypothesis attributes declines in productivity of marine birds and mammals to changes in the species of prey they consume and corresponding differences in nutritional quality of those prey. To test this hypothesis nestling Black-legged Kittiwakes (Rissa tridactyla) and Tufted Puffins (Fratercula cirrhata) were raised in captivity under controlled conditions to determine whether the type and quality of fish consumed by young seabirds constrains their growth and development. Some nestlings were fed rations of Capelin (Mallotus villosus), Herring (Clupea pallasi) or Sand Lance (Ammodytes hexapterus) and their growth was compared with nestlings raised on equal biomass rations of Walleye Pollock (Theragra chalcograma). Nestlings fed rations of herring, sand lance, or capelin experienced higher growth increments than nestlings fed pollock. The energy density of forage fish fed to nestlings had a marked effect on growth increments and could be expected to have an effect on pre- and post-fledging survival of nestlings in the wild. These results provide empirical support for the junk-food hypothesis.

  4. State policies targeting junk food in schools: racial/ethnic differences in the effect of policy change on soda consumption.

    Science.gov (United States)

    Taber, Daniel R; Stevens, June; Evenson, Kelly R; Ward, Dianne S; Poole, Charles; Maciejewski, Matthew L; Murray, David M; Brownson, Ross C

    2011-09-01

    We estimated the association between state policy changes and adolescent soda consumption and body mass index (BMI) percentile, overall and by race/ethnicity. We obtained data on whether states required or recommended that schools prohibit junk food in vending machines, snack bars, concession stands, and parties from the 2000 and 2006 School Health Policies and Programs Study. We used linear mixed models to estimate the association between 2000-2006 policy changes and 2007 soda consumption and BMI percentile, as reported by 90 730 students in 33 states and the District of Columbia in the Youth Risk Behavior Survey, and to test for racial/ethnic differences in the associations. Policy changes targeting concession stands were associated with 0.09 fewer servings of soda per day among students (95% confidence interval [CI] = -0.17, -0.01); the association was more pronounced among non-Hispanic Blacks (0.19 fewer servings per day). Policy changes targeting parties were associated with 0.07 fewer servings per day (95% CI = -0.13, 0.00). Policy changes were not associated with BMI percentile in any group. State policies targeting junk food in schools may reduce racial/ethnic disparities in adolescent soda consumption, but their impact appears to be too weak to reduce adolescent BMI percentile.

  5. State Policies Targeting Junk Food in Schools: Racial/Ethnic Differences in the Effect of Policy Change on Soda Consumption

    Science.gov (United States)

    Stevens, June; Evenson, Kelly R.; Ward, Dianne S.; Poole, Charles; Maciejewski, Matthew L.; Murray, David M.; Brownson, Ross C.

    2011-01-01

    Objectives. We estimated the association between state policy changes and adolescent soda consumption and body mass index (BMI) percentile, overall and by race/ethnicity. Methods. We obtained data on whether states required or recommended that schools prohibit junk food in vending machines, snack bars, concession stands, and parties from the 2000 and 2006 School Health Policies and Programs Study. We used linear mixed models to estimate the association between 2000–2006 policy changes and 2007 soda consumption and BMI percentile, as reported by 90 730 students in 33 states and the District of Columbia in the Youth Risk Behavior Survey, and to test for racial/ethnic differences in the associations. Results. Policy changes targeting concession stands were associated with 0.09 fewer servings of soda per day among students (95% confidence interval [CI] = −0.17, −0.01); the association was more pronounced among non-Hispanic Blacks (0.19 fewer servings per day). Policy changes targeting parties were associated with 0.07 fewer servings per day (95% CI = −0.13, 0.00). Policy changes were not associated with BMI percentile in any group. Conclusions. State policies targeting junk food in schools may reduce racial/ethnic disparities in adolescent soda consumption, but their impact appears to be too weak to reduce adolescent BMI percentile. PMID:21778484

  6. Persuading people to eat less junk food: a cognitive resource match between attitudinal ambivalence and health message framing.

    Science.gov (United States)

    Yan, Changmin

    2015-01-01

    This study investigated the interactive effects of attitudinal ambivalence and health message framing on persuading people to eat less junk food. Within the heuristic-systematic model of information processing, an attitudinal ambivalence (ambivalent or univalent toward eating junk food) by health message framing (advantage- or disadvantage-framed appeals) between-subjects experiment was conducted to explore a cognitive resource-matching effect and the underlying mediation processes. Ambivalent individuals reported a higher level of cognitive elaboration than univalent individuals did. The disadvantage frame engendered more extensive cognitive elaboration than the advantage frame did. Ambivalent individuals were more persuaded by the disadvantage frame and, for them, cognitive elaboration mediated the persuasion process via the systematic route. Univalent individuals were equally persuaded by the advantage frame and the disadvantage frame and, for them, neither the perceived frame valence nor cognitive elaboration mediated persuasion. Discussion of the null results among the univalent group leads to a response-reinforcement explanation. Theoretical and practical implications are discussed.

  7. Children's implicit recall of junk food, alcohol and gambling sponsorship in Australian sport.

    Science.gov (United States)

    Bestman, Amy; Thomas, Samantha L; Randle, Melanie; Thomas, Stuart D M

    2015-10-05

    In Australia, sport is saturated by the promotion of junk food, alcohol and gambling products. This is particularly evident on player jerseys. The effect of this advertising on children, who are exposed to these messages while watching sport, has not been thoroughly investigated. The aim of this research study was to investigate: (1) the extent to which children implicitly recalled shirt sponsors with the correct sporting team; (2) whether children associated some types of sponsors with certain sporting codes more than others; and (3) whether age of the children influenced the correct recall of sponsoring brands and teams. This experimental study conducted in New South Wales, Australia used projective techniques to measure the implicit recall of team sponsorship relationships of 85 children aged 5-12 years. Participants were asked to arrange two sets of magnets - one which contained sporting teams and one which contained brand logos - in the manner deemed most appropriate by them. Children were not given any prompts relating to sporting sponsorship relationships. Three quarters (77 %) of the children were able to identify at least one correct shirt sponsor. Children associated alcohol and gambling brands more highly with the more popular sporting code, the National Rugby League compared to the Australian Football League sporting code. Results showed that age had an effect on number of shirt sponsors correctly recalled with 9-12 year olds being significantly more likely than 5-8 year olds to correctly identify team sponsors. Given children's ability to implicitly recall shirt sponsors in a sporting context, Australian sporting codes should examine their current sponsorship relationships to reduce the number of unhealthy commodity shirt sponsors. While there is some regulation that protects children from the marketing of unhealthy commodity products, these findings suggest that children are still exposed to and recall these sponsorship relationships. Results suggest

  8. Cross-sectional survey of daily junk food consumption, irregular eating, mental and physical health and parenting style of British secondary school children.

    Science.gov (United States)

    Zahra, J; Ford, T; Jodrell, D

    2014-07-01

    Previous research has established that poor diets and eating patterns are associated with numerous adverse health outcomes. This study explored the relationships between two specific eating behaviours (daily junk food consumption and irregular eating) and self-reported physical and mental health of secondary school children, and their association with perceived parenting and child health. 10 645 participants aged between 12 and 16 completed measures of junk food consumption, irregular eating, parental style, and mental and physical health through the use of an online survey implemented within 30 schools in a large British city. 2.9% of the sample reported never eating regularly and while 17.2% reported daily consumption of junk food. Young people who reported eating irregularly and consuming junk food daily were at a significantly greater risk of poorer mental (OR 5.41, 95% confidence interval 4.03-7.25 and 2.75, 95% confidence interval 1.99-3.78) and physical health (OR 4.56, 95% confidence interval 3.56-5.85 and 2.00, 95% confidence interval 1.63-2.47). Authoritative parenting was associated with healthier eating behaviours, and better mental and physical health in comparison to other parenting styles. A worrying proportion of secondary school children report unhealthy eating behaviours, particularly daily consumption of junk food, which may be associated with poorer mental and physical health. Parenting style may influence dietary habits. Interventions to improve diet may be more beneficial if also they address parenting strategies and issues related to mental and physical health. © 2013 John Wiley & Sons Ltd.

  9. Association of junk food consumption with high blood pressure and obesity in Iranian children and adolescents: the CASPIAN-IV Study

    Directory of Open Access Journals (Sweden)

    Moloud Payab

    2015-04-01

    Full Text Available OBJECTIVE: This study aimed to evaluate the association of junk food consumption with hypertension and obesity in a national sample of Iranian children and adolescents. METHODS: This nationwide study was conducted in 2011-2012 among 14,880 students, aged 6-18 years, selected by cluster sampling from 30 provinces. Weight, height, waist circumference (WC, hip circumference (HC, waist-to-hip ratio (WHR, waist-to-height ratio (WHtR, as well as systolic and diastolic blood pressure (BP were measured. Junk food was divided into four categories, including salty snacks, sweets, sweetened beverages, and fast food. Subjects reported how many times they had consumed each item (daily, weekly, and seldom. RESULTS: The intake of sweets was significantly associated with anthropometric indices and BP levels. Moreover, a significant association was found between fast food consumption, BP levels, and anthropometric indices (except for WHtR and WHR. Sweet beverages consumption was significantly associated with anthropometric indices; however, the consumption of salty snacks was only significantly associated with height, HC, and WHR. The risk of general obesity (OR: 0.75, 95% CI: 0.65-0.87 and abdominal obesity (OR: 0.81, 95% CI: 0.72-0.92 among participants who seldom consumed sweets was less than those who consumed daily. Also, the risk of general obesity (OR: 0.85, 95% CI: 0.74-0.97 among students that seldom consumed sweetened beverages was less than subjects who consumed them on a daily basis. CONCLUSION: It was found that junk food consumption increased the risk of both general and abdominal obesity; therefore, consumption of junk food should be reduced via restricting TV advertisements and increasing taxes on junk foods.

  10. Association of junk food consumption with high blood pressure and obesity in Iranian children and adolescents: the CASPIAN-IV Study.

    Science.gov (United States)

    Payab, Moloud; Kelishadi, Roya; Qorbani, Mostafa; Motlagh, Mohammad Esmaeil; Ranjbar, Shirin Hasani; Ardalan, Gelayol; Zahedi, Hoda; Chinian, Mohammad; Asayesh, Hamid; Larijani, Bagher; Heshmat, Ramin

    2015-01-01

    This study aimed to evaluate the association of junk food consumption with hypertension and obesity in a national sample of Iranian children and adolescents. This nationwide study was conducted in 2011-2012 among 14,880 students, aged 6-18 years, selected by cluster sampling from 30 provinces. Weight, height, waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), as well as systolic and diastolic blood pressure (BP) were measured. Junk food was divided into four categories, including salty snacks, sweets, sweetened beverages, and fast food. Subjects reported how many times they had consumed each item (daily, weekly, and seldom). The intake of sweets was significantly associated with anthropometric indices and BP levels. Moreover, a significant association was found between fast food consumption, BP levels, and anthropometric indices (except for WHtR and WHR). Sweet beverages consumption was significantly associated with anthropometric indices; however, the consumption of salty snacks was only significantly associated with height, HC, and WHR. The risk of general obesity (OR: 0.75, 95% CI: 0.65-0.87) and abdominal obesity (OR: 0.81, 95% CI: 0.72-0.92) among participants who seldom consumed sweets was less than those who consumed daily. Also, the risk of general obesity (OR: 0.85, 95% CI: 0.74-0.97) among students that seldom consumed sweetened beverages was less than subjects who consumed them on a daily basis. It was found that junk food consumption increased the risk of both general and abdominal obesity; therefore, consumption of junk food should be reduced via restricting TV advertisements and increasing taxes on junk foods. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  11. Junk food diet-induced obesity increases D2 receptor autoinhibition in the ventral tegmental area and reduces ethanol drinking.

    Science.gov (United States)

    Cook, Jason B; Hendrickson, Linzy M; Garwood, Grant M; Toungate, Kelsey M; Nania, Christina V; Morikawa, Hitoshi

    2017-01-01

    Similar to drugs of abuse, the hedonic value of food is mediated, at least in part, by the mesostriatal dopamine (DA) system. Prolonged intake of either high calorie diets or drugs of abuse both lead to a blunting of the DA system. Most studies have focused on DAergic alterations in the striatum, but little is known about the effects of high calorie diets on ventral tegmental area (VTA) DA neurons. Since high calorie diets produce addictive-like DAergic adaptations, it is possible these diets may increase addiction susceptibility. However, high calorie diets consistently reduce psychostimulant intake and conditioned place preference in rodents. In contrast, high calorie diets can increase or decrease ethanol drinking, but it is not known how a junk food diet (cafeteria diet) affects ethanol drinking. In the current study, we administered a cafeteria diet consisting of bacon, potato chips, cheesecake, cookies, breakfast cereals, marshmallows, and chocolate candies to male Wistar rats for 3-4 weeks, producing an obese phenotype. Prior cafeteria diet feeding reduced homecage ethanol drinking over 2 weeks of testing, and transiently reduced sucrose and chow intake. Importantly, cafeteria diet had no effect on ethanol metabolism rate or blood ethanol concentrations following 2g/kg ethanol administration. In midbrain slices, we showed that cafeteria diet feeding enhances DA D2 receptor (D2R) autoinhibition in VTA DA neurons. These results show that junk food diet-induced obesity reduces ethanol drinking, and suggest that increased D2R autoinhibition in the VTA may contribute to deficits in DAergic signaling and reward hypofunction observed with obesity.

  12. The Effect of nutrition education on knowledge, attitude, and performance about junk food consumption among students of female primary schools.

    Science.gov (United States)

    Vardanjani, Ali Esmaeili; Reisi, Mahnoush; Javadzade, Homamodin; Pour, Zabihollah Gharli; Tavassoli, Elahe

    2015-01-01

    Undoubtedly, proper nutrition has important role in safeguarding the individual from many diseases, especially chronic ones, and increasing ones physical and intellectual efficiency. Considering the importance of nutrition education to school-age kids, this research was done with the purpose of determining the effect of nutrition education on the knowledge, attitude, and performance of female students at primary school about junk food consumption. This is an experimental intervention study in Shahr-e-kord city about the reduction of junk foods consumption in 2011. Seventy-two primary girl students were randomly divided into 2 groups, experimental (36) and controls (36). Before of the educational program, self-administrative questionnaire and FFQ (Food Frequency Questionnaire) questionnaire were filled out for both the groups. The self-administrative questionnaire was completed 3 times (before, immediately, and 2 months after education), and FFQ questionnaire was completed 2 times (before and 2 months after education) by students. After pre-test, 4 educational session classes in experimental group were performed. Finally, data were collected and analyzed by SPSS 16 computer software. Demographic variables of the studied population in 2 groups were similar. Before intervention, there were no significant differences regarding the knowledge, attitude, and performance in 2 groups (P > 0/05). After intervention, there were significant differences in the levels of knowledge, attitude, and performance between experimental and control groups (P < 0.001). According to the results, intervention has positive impact on pattern of nutrition, and it can be concluded that intervention is effective on increasing or improving the knowledge, attitude, and performance of the students.

  13. Consuming a low-fat diet from weaning to adulthood reverses the programming of food preferences in male, but not in female, offspring of 'junk food'-fed rat dams.

    Science.gov (United States)

    Ong, Z Y; Muhlhausler, B S

    2014-01-01

    This study aimed to determine whether the negative effects of maternal 'junk food' feeding on food preferences and gene expression in the mesolimbic reward system could be reversed by weaning the offspring onto a low-fat diet. Offspring of control (n = 11) and junk food-fed (JF, n = 12) dams were weaned onto a standard rodent chow until 6 weeks (juvenile) or 3 months (adult). They were then given free access to both chow and junk food for 3 weeks and food preferences determined. mRNA expression of key components of the mesolimbic reward system was determined by qRT-PCR at 6 weeks, 3 and 6 months of age. In the juvenile group, both male and female JF offspring consumed more energy and carbohydrate during the junk food exposure at 6 weeks of age and had a higher body fat mass at 3 months (P junk food; however, female JF offspring had a higher body fat mass at 6 months (P junk food exposure on food preferences and fat mass can be reversed by consuming a low-fat diet from weaning to adulthood in males. Females, however, retain a higher propensity for diet-induced obesity even after consuming a low-fat diet for an extended period after weaning. © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  14. Association between energy drink intake, sleep, stress, and suicidality in Korean adolescents: energy drink use in isolation or in combination with junk food consumption

    OpenAIRE

    Park, Subin; Lee, Yeeun; Lee, Junghyun H.

    2016-01-01

    Background A considerable amount of research suggests that the frequent use of caffeinated energy drinks may be associated with undesirable effects, particularly so in children and adolescents. This study aimed to investigate the associations between energy drink intake and mental health problems, in isolation or in combination with junk food consumption, in a nationally representative sample of Korean adolescents. Methods Data from the 2015 Korean Youth Risk Behavior Web-Based Survey, collec...

  15. Assessment of the Situation and the Cause of Junk Food Consumption in Iran and Recommendation of Interventions for Reducing its Consumption

    Directory of Open Access Journals (Sweden)

    Behzad Damari

    2016-05-01

    Full Text Available Background and Objective: The consumption of junk food in Iran is alarmingly increasing. This study aimed to determine the influencing factors of junk food consumption and amendable interventions for decreasing  the consumption.Materials and Methods: In this qualitative study, Valid documentations were collected by searching the database using related key words and the key points were imported in a checklist and after identifying and prioritizing stakeholders through stakeholder analysis method, it was provided to stakeholders in the form of a questionnaire. The qualitative Method was Delphi. The questionnaire was sent by email to stakeholders and they asked to select and prioritize problems and required interventions. Consensus was reached after three rounds.      Results: The study showed that mean junk food consumption was high in Iran, especially in children and adolescents and the most important influencing factors was availability, low price, the impact of media, taste preferences, diversity and attractiveness of the package, inadequate awareness and lifestyle changes. Recommended interventions by stakeholders was including creation of a supportive environment, educational interventions, increased access to healthy food and control junk-food advertising in the media and imposed major changes in supportive priorities of  ministry of industry and mining toward producing healthy snacks.Conclusion: According to the findings, in line with public Policymaking, presentation of the results of this study as an advocacy paper to health policymakers and integrating it in the operational programs of the ministries of Health and Education and the media and holding supportive meetings with the producers of alternative products is proposed.

  16. Does breast-feeding reduce offspring junk food consumption during childhood? Examinations by socio-economic status and race/ethnicity.

    Science.gov (United States)

    Jackson, Dylan B; Johnson, Kecia R

    2017-06-01

    To examine whether breast-feeding duration and socio-economic status (SES) interact to predict junk food consumption among offspring and whether the interaction differs across racial/ethnic groups. Survey research using a longitudinal panel design. Hierarchical linear regression was used to analyse the data. In-home interviews with the child's parents over a 5-year period across the USA. Approximately 10 000 American children from the Early Childhood Longitudinal Study: Birth Cohort (ECLS-B). The findings revealed that longer breast-feeding durations correspond to lower levels of junk food consumption, but that this relationship emerges consistently only among low-SES blacks. Efforts to promote breast-feeding among low-SES black women may have the added benefit of reducing their children's junk food intake, and may thereby promote their general health and well-being. Future research should seek to explore the mechanisms by which breast-feeding might benefit the dietary habits of low-SES black children.

  17. Maternal “junk-food” feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring

    Science.gov (United States)

    Ong, Z. Y.; Muhlhausler, B. S.

    2011-01-01

    Individuals exposed to high-fat, high-sugar diets before birth have an increased risk of obesity in later life. Recent studies have shown that these offspring exhibit increased preference for fat, leading to suggestions that perinatal exposure to high-fat, high-sugar foods results in permanent changes within the central reward system that increase the subsequent drive to overconsume palatable foods. The present study has determined the effect of a maternal “junk-food” diet on the expression of key components of the mesolimbic reward pathway in the offspring of rat dams at 6 wk and 3 mo of age. We show that offspring of junk-food-fed (JF) dams exhibit higher fat intake from weaning until at least 3 mo of age (males: 16±0.6 vs. 11±0.8 g/kg/d; females: 19±1.3 vs. 13±0.4 g/kg/d; Pjunk-food intake in postnatal life.—Ong, Z. Y., Muhlhausler, B. S. Maternal “junk-food” feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring. PMID:21427213

  18. Junk-food enhances conditioned food cup approach to a previously established food cue, but does not alter cue potentiated feeding; implications for the effects of palatable diets on incentive motivation.

    Science.gov (United States)

    Derman, Rifka C; Ferrario, Carrie R

    2018-03-16

    Efforts to stem the global rise in obesity have been minimally effective, perhaps in part because our understanding of the psychological and behavioral drivers of obesity is limited. It is well established that stimuli that are paired with palatable foods can powerfully influence food-seeking and feeding behaviors. However, how consumption of sugary, fatty "junk-foods" affects these motivational responses to food cues is poorly understood. Here, we determined the effects of short- and long-term "junk-food" consumption on the expression of cue potentiated feeding and conditioned food cup approach to Pavlovian conditioned stimuli (CS). Further, to determine the degree to which effects of "junk-food" were selective to Pavlovian motivational processes, we varied the predictive validity of the CS by including training groups conditioned with unique CS-US contingencies ranging from -1.0 to +1.0. "Junk-food" did not enhance cue potentiated feeding in any group, but expression of this potentiation effect varied with the CS-US contingency independent of diet. In contrast, "junk-food" consistently enhanced conditioned approach to the food cup; this effect was dependent on the previously established CS-US contingency. That is, consumption of "junk-food" following training enhanced approach to the food cup only in response to CSs with previously positive CS-US contingencies. This was accompanied by reduced motivation for the US itself. Together these data show that "junk-food" consumption selectively enhances incentive motivational responses to previously established food CSs, without altering cue potentiated feeding induced by these same CSs, and in the absence of enhanced motivation for food itself. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Effects of Junk Foods on Brain Neurotransmitters (Dopamine and Serotonin) and some Biochemical Parameters in Albino Rats

    International Nuclear Information System (INIS)

    Abd Elmonem, H.A.; Ali, E.A.

    2011-01-01

    Nutritional Habits have changed significantly and junk foods have become widely popular, in recent years. The present study aimed to shed the light on the effect of potato chips and / or ketchup consumption on some biochemical parameters. Sixty four male and female albino rats were used in the study. Animals were maintained on 0.25 g potato chips/ rat and / or 0.125 g ketchup / rat, 5 days a week for 4 weeks. Potato chips showed the lowest body wt gain in the male rats after 4 weeks but, ketchup modulated this negative effect of the potato chips in the group of male animals fed on potato chips plus ketchup. Potato chips significantly decreased brain serotonin, liver glutathione (GSH) and catalase (CAT) in both sexes; brain dopamine, serum total proteins, albumin, total globulins, α 2 - and β 1 -globulins in the females and serum thyroxine (T 4 ) in the male rats. Ketchup apparently affected serum T 4 and A / G ratio in both sexes, brain dopamine and liver GSH in the males in addition to brain serotonin, serum total globulins and ?1-globulin in the female rats. Potato chips plus ketchup significantly changed T 4 , dopamine, GSH, CAT, α 1 and α 2 -globulins in both sexes; serotonin and β 1 -globulin in the male rats, total proteins and albumin in the females. It could be concluded that potato chips consumption might induce numerous adverse effects in various body organs

  20. Relationship between junk foods intake and weight in 6-7 years old children, Shahin Shahr and Meymeh, Iran

    Science.gov (United States)

    Darvishi, Leila; Ghiasvand, Reza; Ashrafi, Maryam; Ashrafzadeh, Elnaz; Askari, Gholamreza; Shiranian, Afshin; Hasanzadeh, Akbar

    2013-01-01

    Background: Healthy nutrition is very important considering the weight status especially in children. The aim of this study was to assess the relationship between junk foods intake and weight in 6-7-years old children. Materials and Methods: This cross-sectional study was carried out in Shahin Shahr and Meymeh, Iran, in 2009. Anthropometrics measures were done and 24-hour food recall used for dietary information and analyzed with food processor 2 and then compared with dietary reference intakes 2008 (DRI). Findings: 61.1 percent of the subjects were residing in dormitories and 12.7 percent were marred. Prevalence of overweight or obesity and abdominal obesity was 6.9 percent and 46.1 percent respectively. Mean (±SD) systolic blood pressure was 105.2 ± 15.6 mm/Hg and diastolic was 62.2 ± 10.4 mm/Hg. Totally, 3.9 percent of the subjects had hypertension. The analysis of food intake indicate that (B12, folate, magnesium, potassium, calcium) with level below the recommended ones, and (vitamin C, E, pantothenic acid, B1, B3, phosphate, zinc) with up levels the recommended ones, and energy intake, macronutrient, vitamin A, pyridoxine, iron, selenium were in general appropriate. Conclusion: These results indicated appropriate level of macronutrients intake and unbalance mainly existed in micronutrients. It is recommended to increase intake important food groups such as dairy, vegetable, fruit that include good source of micronutrients, and also it is suggested that need for strategies can improve competence in the area of nutrition. PMID:24083252

  1. Association between energy drink intake, sleep, stress, and suicidality in Korean adolescents: energy drink use in isolation or in combination with junk food consumption.

    Science.gov (United States)

    Park, Subin; Lee, Yeeun; Lee, Junghyun H

    2016-10-13

    A considerable amount of research suggests that the frequent use of caffeinated energy drinks may be associated with undesirable effects, particularly so in children and adolescents. This study aimed to investigate the associations between energy drink intake and mental health problems, in isolation or in combination with junk food consumption, in a nationally representative sample of Korean adolescents. Data from the 2015 Korean Youth Risk Behavior Web-Based Survey, collected from 68,043 adolescents aged 12-18 years (mean age 15.09 ± 1.72 years), were analyzed. Questionnaires were administered to collect information related to dietary behavior including energy drink intake and junk food consumption. Single item measures of sleep dissatisfaction, stress, depression, suicidal ideation, suicide plan, and suicide attempt were also administered. Associations between energy drink intake and sleep dissatisfaction, perceived severe stress, persistent depressive mood, and suicidality were investigated, and a multivariate approach was taken so that additional variance from demographic and lifestyle factors could be controlled for statistically. Energy drink intake was significantly associated with sleep dissatisfaction (adjusted odd ratios [AORs] = 1.64 and 1.25), severe stress (AORs = 2.23 and 1.38), depressive mood (AOR = 2.59 and 1.51), suicidal ideation (AORs = 3.14 and 1.43), suicide plan (AORs = 4.65 and 1.78), and suicide attempt (AORs = 6.79 and 1.91), with a higher risk for more frequent use of energy drinks (≥5 times/wk) than for less frequent use (1-4 times/wk). The detrimental effect of energy drinks on mental health was particularly prominent in frequent junk food consumers. Our data suggest that energy drink intake had detrimental effects related to stress, sleep dissatisfaction, mood, and suicidality, in isolation or in combination with junk food consumption, in Korean adolescents. However, the cross-sectional study design

  2. Maternal "junk-food" feeding of rat dams alters food choices and development of the mesolimbic reward pathway in the offspring.

    Science.gov (United States)

    Ong, Z Y; Muhlhausler, B S

    2011-07-01

    Individuals exposed to high-fat, high-sugar diets before birth have an increased risk of obesity in later life. Recent studies have shown that these offspring exhibit increased preference for fat, leading to suggestions that perinatal exposure to high-fat, high-sugar foods results in permanent changes within the central reward system that increase the subsequent drive to overconsume palatable foods. The present study has determined the effect of a maternal "junk-food" diet on the expression of key components of the mesolimbic reward pathway in the offspring of rat dams at 6 wk and 3 mo of age. We show that offspring of junk-food-fed (JF) dams exhibit higher fat intake from weaning until at least 3 mo of age (males: 16 ± 0.6 vs. 11 ± 0.8 g/kg/d; females: 19 ± 1.3 vs. 13 ± 0.4 g/kg/d; Pjunk-food intake in postnatal life.

  3. Sex and age-dependent effects of a maternal junk food diet on the mu-opioid receptor in rat offspring.

    Science.gov (United States)

    Gugusheff, Jessica R; Bae, Sung Eun; Rao, Alexandra; Clarke, Iain J; Poston, Lucilla; Taylor, Paul D; Coen, Clive W; Muhlhausler, Beverly S

    2016-03-15

    Perinatal junk food exposure increases the preference for palatable diets in juvenile and adult rat offspring. Previous studies have implicated reduced sensitivity of the opioid pathway in the programming of food preferences; however it is not known when during development these changes in opioid signalling first emerge. This study aimed to determine the impact of a maternal junk food (JF) diet on mu-opioid receptor (MuR) expression and ligand binding in two key regions of the reward pathway, the nucleus accumbens (NAc) and the ventral tegmental area (VTA) in rats during the early suckling (postnatal day (PND) 1 and 7) and late suckling/early post-weaning (PND 21 and 28) periods. Female rats were fed either a JF or a control diet for two weeks prior to mating and throughout pregnancy and lactation. MuR expression in the VTA was significantly reduced in female JF offspring on PND 21 and 28 (by 32% and 57% respectively, Pjunk food exposure on MuR mRNA expression or binding were detected at these time points in male offspring. These findings provide evidence that the opioid signalling system is a target of developmental programming by the end of the third postnatal week in females, but not in males. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Contexts Paired with Junk Food Impair Goal-Directed Behavior in Rats: Implications for Decision Making in Obesogenic Environments.

    Science.gov (United States)

    Kendig, Michael D; Cheung, Ambrose M K; Raymond, Joel S; Corbit, Laura H

    2016-01-01

    The high prevalence of obesity and related metabolic diseases calls for greater understanding of the factors that drive excess energy intake. Calorie-dense palatable foods are readily available and often are paired with highly salient environmental cues. These cues can trigger food-seeking and consumption in the absence of hunger. Here we examined the effects of palatable food-paired environmental cues on control of instrumental food-seeking behavior. In Experiment 1, adult male rats received exposures to one context containing three "junk" foods (JFs context) and another containing chow (Chow context). Next, rats were food-deprived and trained to perform instrumental responses (lever-press) for two novel food rewards in a third, distinct context. Contextual influences on flexible control of food-seeking behavior were then assessed by outcome devaluation tests held in the JF, chow and training contexts. Devaluation was achieved using specific satiety and test order was counterbalanced. Rats exhibited goal-directed control over behavior when tested in the training and chow-paired contexts. Notably, performance was habitual (insensitive to devaluation) when tested in the JF context. In Experiment 2 we tested whether the impairment found in the JF context could be ameliorated by the presentation of a discrete auditory cue paired with the chow context, relative to a second cue paired with the JF context. Consistent with the results of Experiment 1, the devaluation effect was not significant when rats were tested in the JF context with the JF cue. However, presenting the chow cue increased the impact of the devaluation treatment leading to a robust devaluation effect. Further tests confirmed that performance in the chow context was goal-directed and that sensory-specific satiety in the JF context was intact. These results show that environments paired with palatable foods can impair goal-directed control over food-seeking behavior, but that this deficit was improved by

  5. Junk Yard Treasures

    Science.gov (United States)

    Mathes, Len

    2009-01-01

    The author describes a project that she developed as a challenge for her students and ended up with some fantastic student paintings. The author told her group of reluctant art students they must first research on the Internet for old, junky cars. The older and more junky the cars, the better. Once a vehicle is selected, it is driven into Adobe…

  6. Quality Minus Junk

    DEFF Research Database (Denmark)

    Asness, Clifford S.; Frazzini, Andrea; Heje Pedersen, Lasse

    We define a quality security as one that has characteristics that, all-else-equal, an investor should be willing to pay a higher price for: stocks that are safe, profitable, growing, and well managed. High-quality stocks do have higher prices on average, but not by a very large margin. Perhaps....... The price of quality – i.e., how much investors pay extra for higher quality stocks – varies over time, reaching a low during the internet bubble. Further, a low price of quality predicts a high future return of QMJ. Finally, controlling for quality resurrects the otherwise moribund size effect....

  7. Implantation of the NC ISO 9001 in the Radioactivity measurement service in junks of CPHR; Implantacion de la NC ISO 9001 en el servicio de medicion de radiactividad en chatarras de CPHR

    Energy Technology Data Exchange (ETDEWEB)

    Ramos V, E O; Dominguez L, O; Capote F, E; Fernandez G, I M; Caveda R, C; Alonso A, D; Barroso P, I; Madraso M, S [CPHR, Calle 20 No. 4113 e/41 y 47 Playa, C.P. 11300, Ciudad La Habana, Direccion Postal A.P. 6195, C.P. 10600 (Cuba)

    2006-07-01

    In the last years in the international environment, radiological incidents have been reported, due to the presence of radioactive materials in the junk, that have implied the adoption of measures in matter of radiological safety, to avoid affectations in the public and the environment, as well as in the international trade. The establishment of the radiological control of junk during it commercialization requires of the implantation of a quality management program. In such sense, the present work exposes the experience of our institution in the design and organization of a service for the radioactivity measurement in junks based on a quality administration system based on the requirements of the quality standards ISO 9001:2000, ISO/IEC 17050 and ISO/IEC 17025:2000. In coherence with the postulates defined in the institutional strategy related to the implantation of a total quality system and the international demands on this matter. To such ends the processes that compose the service were identified, the corresponding and implemented procedures were elaborated, the registrations associated to the same one, being worked in the design of a quality assurance program that allowed the evaluation of the conformity of the product and the customer. (Author)

  8. The effects of prenatal exposure to a 'junk food' diet on offspring food preferences and fat deposition can be mitigated by improved nutrition during lactation.

    Science.gov (United States)

    Gugusheff, J R; Vithayathil, M; Ong, Z Y; Muhlhausler, B S

    2013-10-01

    Exposure to a maternal junk food (JF) diet in utero and during the suckling period has been demonstrated to increase the preference for palatable food and increase the susceptibility to diet-induced obesity in adult offspring. We aimed to determine whether the effects of prenatal exposure to JF could be ameliorated by cross-fostering offspring onto dams consuming a standard rodent chow during the suckling period. We report here that when all offspring were given free access to the JF diet for 7 weeks from 10 weeks of age, male offspring of control (C) or JF dams that were cross-fostered at birth onto JF dams (C-JF, JF-JF), exhibited higher fat (C-C: 12.3 ± 0.34 g/kg/day; C-JF: 14.7 ± 1.04 g/kg/day; JF-C: 11.5 ± 0.41 g/kg/day; JF-JF: 14.0 ± 0.44 g/kg/day; P food intake, had increased fat mass as percentage of body weight (C-C: 19.9 ± 1.33%; C-JF: 22.8 ± 1.57%; JF-C: 17.4 ± 1.03%; JF-JF: 22.0 ± 1.0%; P food preferences in females and susceptibility to diet-induced obesity in males can be prevented by improved nutrition during the suckling period.

  9. Perception v. actual intakes of junk food and sugar-sweetened beverages in Australian young adults: assessed using the mobile food record.

    Science.gov (United States)

    Harray, Amelia J; Boushey, Carol J; Pollard, Christina M; Panizza, Chloe E; Delp, Edward J; Dhaliwal, Satvinder S; Kerr, Deborah A

    2017-09-01

    To determine perception v. actual intakes of energy-dense nutrient-poor 'junk food' (JF) and sugar-sweetened beverages (SSB) in young adults, using the mobile food record (mFR). Before-and-after eating images using a 4 d mFR were assessed for standardised 600 kJ (143 kcal) servings of JF and SSB (excluding diet drinks). Participants reported their concern about the health aspects of their diet, perceptions and intentions regarding JF and SSB. Perth, Western Australia. Adults (n 246) aged 18-30 years. The mean (sd) intake of JF+SSB was 3·7 (2·0) servings/d. Women thinking about drinking less SSB consumed more SSB servings/d (1·5 (1·2)) than men (0·7 (0·5); P<0·05) who were thinking about drinking less. Men not thinking about cutting down JF consumed more servings/d (4·6 (2·4)) than women (2·5 (0·7); P<0·01) who were not thinking about cutting down. Those who paid a lot of attention to the health aspects of their diet consumed less JF+SSB than those who took only a bit of notice (P<0·001), were not really thinking much about it (P<0·001) or who didn't think at all about the health aspects of food (P<0·01). Perceptions and attitudes regarding JF and SSB were associated with level of consumption. Those not thinking about cutting down their intake of these foods represent an important target group as they consume more than their peers. Further research is needed to identify how amenable young adults are to changing their intake, particularly given the lack of attention paid to the health aspects of their diet.

  10. Modern 'junk food' and minimally-processed 'natural food' cafeteria diets alter the response to sweet taste but do not impair flavor-nutrient learning in rats.

    Science.gov (United States)

    Palframan, Kristen M; Myers, Kevin P

    2016-04-01

    Animals learn to prefer and increase consumption of flavors paired with postingestive nutrient sensing. Analogous effects have been difficult to observe in human studies. One possibility is experience with the modern, processed diet impairs learning. Food processing manipulates flavor, texture, sweetness, and nutrition, obscuring ordinary correspondences between sensory cues and postingestive consequences. Over time, a diet of these processed 'junk' foods may impair flavor-nutrient learning. This 'flavor-confusion' hypothesis was tested by providing rats long-term exposure to cafeteria diets of unusual breadth (2 or 3 foods per day, 96 different foods over 3 months, plus ad libitum chow). One group was fed processed foods (PF) with added sugars/fats and manipulated flavors, to mimic the sensory-nutrient properties of the modern processed diet. Another group was fed only 'natural' foods (NF) meaning minimally-processed foods without manipulated flavors or added sugars/fats (e.g., fresh fruits, vegetables, whole grains) ostensibly preserving the ordinary correspondence between flavors and nutrition. A CON group was fed chow only. In subsequent tests of flavor-nutrient learning, PF and NF rats consistently acquired strong preferences for novel nutrient-paired flavors and PF rats exhibited enhanced learned acceptance, contradicting the 'flavor-confusion' hypothesis. An unexpected finding was PF and NF diets both caused lasting reduction in ad lib sweet solution intake. Groups did not differ in reinforcing value of sugar in a progressive ratio task. In lick microstructure analysis the NF group paradoxically showed increased sucrose palatability relative to PF and CON, suggesting the diets have different effects on sweet taste evaluation. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Censorship and Junk Food Journalism.

    Science.gov (United States)

    Jensen, Carl

    1984-01-01

    Discusses journalistic phenomenon whereby Americans are inundated with same news with only names, dates, and locations changing. Highlights include news explosion, well-documented news, why "Ten Most Censored Stories" chosen by Project Censored (Sonoma State University, California) are not covered by major news media, federal policies,…

  12. The Impact of Curtin University's Activity, Food and Attitudes Program on Physical Activity, Sedentary Time and Fruit, Vegetable and Junk Food Consumption among Overweight and Obese Adolescents: A Waitlist Controlled Trial

    Science.gov (United States)

    Straker, Leon M.; Howie, Erin K.; Smith, Kyla L.; Fenner, Ashley A.; Kerr, Deborah A.; Olds, Tim S.; Abbott, Rebecca A.; Smith, Anne J.

    2014-01-01

    Background To determine the effects of participation in Curtin University's Activity, Food and Attitudes Program (CAFAP), a community-based, family-centered behavioural intervention, on the physical activity, sedentary time, and healthy eating behaviours of overweight and obese adolescents. Methods In this waitlist controlled clinical trial in Western Australia, adolescents (n = 69, 71% female, mean age 14.1 (SD 1.6) years) and parents completed an 8-week intervention followed by 12 months of telephone and text message support. Assessments were completed at baseline, before beginning the intervention, immediately following the intervention, and at 3-, 6-, and 12- months follow-up. The primary outcomes were physical activity and sedentary time assessed by accelerometers and servings of fruit, vegetables and junk food assessed by 3-day food records. Results During the intensive 8-week intervention sedentary time decreased by −5.1 min/day/month (95% CI: −11.0, 0.8) which was significantly greater than the rate of change during the waitlist period (p = .014). Moderate physical activity increased by 1.8 min/day/month (95% CI: −0.04, 3.6) during the intervention period, which was significantly greater than the rate of change during the waitlist period (p = .041). Fruit consumption increased during the intervention period (monthly incidence rate ratio (IRR) 1.3, 95% CI: 1.10, 1.56) and junk food consumption decreased (monthly IRR 0.8, 95% CI: 0.74, 0.94) and these changes were different to those seen during the waitlist period (p = .004 and p = .020 respectively). Conclusions Participating in CAFAP appeared to have a positive influence on the physical activity, sedentary and healthy eating behaviours of overweight and obese adolescents and many of these changes were maintained for one year following the intensive intervention. Trial Registration Australia and New Zealand Clinical Trials Registry ACTRN12611001187932 PMID:25375109

  13. The impact of Curtin University's activity, food and attitudes program on physical activity, sedentary time and fruit, vegetable and junk food consumption among overweight and obese adolescents: a waitlist controlled trial.

    Science.gov (United States)

    Straker, Leon M; Howie, Erin K; Smith, Kyla L; Fenner, Ashley A; Kerr, Deborah A; Olds, Tim S; Abbott, Rebecca A; Smith, Anne J

    2014-01-01

    To determine the effects of participation in Curtin University's Activity, Food and Attitudes Program (CAFAP), a community-based, family-centered behavioural intervention, on the physical activity, sedentary time, and healthy eating behaviours of overweight and obese adolescents. In this waitlist controlled clinical trial in Western Australia, adolescents (n = 69, 71% female, mean age 14.1 (SD 1.6) years) and parents completed an 8-week intervention followed by 12 months of telephone and text message support. Assessments were completed at baseline, before beginning the intervention, immediately following the intervention, and at 3-, 6-, and 12- months follow-up. The primary outcomes were physical activity and sedentary time assessed by accelerometers and servings of fruit, vegetables and junk food assessed by 3-day food records. During the intensive 8-week intervention sedentary time decreased by -5.1 min/day/month (95% CI: -11.0, 0.8) which was significantly greater than the rate of change during the waitlist period (p = .014). Moderate physical activity increased by 1.8 min/day/month (95% CI: -0.04, 3.6) during the intervention period, which was significantly greater than the rate of change during the waitlist period (p = .041). Fruit consumption increased during the intervention period (monthly incidence rate ratio (IRR) 1.3, 95% CI: 1.10, 1.56) and junk food consumption decreased (monthly IRR 0.8, 95% CI: 0.74, 0.94) and these changes were different to those seen during the waitlist period (p = .004 and p = .020 respectively). Participating in CAFAP appeared to have a positive influence on the physical activity, sedentary and healthy eating behaviours of overweight and obese adolescents and many of these changes were maintained for one year following the intensive intervention. Australia and New Zealand Clinical Trials Registry ACTRN12611001187932.

  14. The impact of Curtin University's activity, food and attitudes program on physical activity, sedentary time and fruit, vegetable and junk food consumption among overweight and obese adolescents: a waitlist controlled trial.

    Directory of Open Access Journals (Sweden)

    Leon M Straker

    Full Text Available To determine the effects of participation in Curtin University's Activity, Food and Attitudes Program (CAFAP, a community-based, family-centered behavioural intervention, on the physical activity, sedentary time, and healthy eating behaviours of overweight and obese adolescents.In this waitlist controlled clinical trial in Western Australia, adolescents (n = 69, 71% female, mean age 14.1 (SD 1.6 years and parents completed an 8-week intervention followed by 12 months of telephone and text message support. Assessments were completed at baseline, before beginning the intervention, immediately following the intervention, and at 3-, 6-, and 12- months follow-up. The primary outcomes were physical activity and sedentary time assessed by accelerometers and servings of fruit, vegetables and junk food assessed by 3-day food records.During the intensive 8-week intervention sedentary time decreased by -5.1 min/day/month (95% CI: -11.0, 0.8 which was significantly greater than the rate of change during the waitlist period (p = .014. Moderate physical activity increased by 1.8 min/day/month (95% CI: -0.04, 3.6 during the intervention period, which was significantly greater than the rate of change during the waitlist period (p = .041. Fruit consumption increased during the intervention period (monthly incidence rate ratio (IRR 1.3, 95% CI: 1.10, 1.56 and junk food consumption decreased (monthly IRR 0.8, 95% CI: 0.74, 0.94 and these changes were different to those seen during the waitlist period (p = .004 and p = .020 respectively.Participating in CAFAP appeared to have a positive influence on the physical activity, sedentary and healthy eating behaviours of overweight and obese adolescents and many of these changes were maintained for one year following the intensive intervention.Australia and New Zealand Clinical Trials Registry ACTRN12611001187932.

  15. Association between junk food consumption and fast-food outlet access near school among Quebec secondary-school children: findings from the Quebec Health Survey of High School Students (QHSHSS) 2010-11.

    Science.gov (United States)

    Cutumisu, Nicoleta; Traoré, Issouf; Paquette, Marie-Claude; Cazale, Linda; Camirand, Hélène; Lalonde, Benoit; Robitaille, Eric

    2017-04-01

    We investigated the association between junk food consumption at lunchtime (JCL) and fast-food outlet access near school among secondary-school children in Quebec. A geographic information system database was used to characterize the food environment around a sub-sample of 374 public schools in which 26 655 students were enrolled. The outcome variable was JCL during the previous week, dichotomized into low JCL (none or once) v. high JCL (twice or more). Access to fast-food outlets near school was assessed using an existing database of fast-food outlets in Quebec. Covariates included student (age, sex and self-rated perceived health), family (familial status and parental education) and school (urban/rural status and deprivation) variables. Hierarchical logistic regression models were employed for analyses using PROC GLIMMIX of SAS version 9.3. Province of Quebec, Canada. We used data from the Quebec Health Survey of High School Students (QHSHSS) 2010-11, a survey of secondary-school Quebec students. Exposure to two or more fast-food outlets within a radius of 750 m around schools was associated with a higher likelihood of excess JCL (OR=1·50; 95 % CI 1·28, 1·75), controlling for the characteristics of the students, their families and their schools. The food environment surrounding schools can constitute a target for interventions to improve food choices among secondary-school children living in the province of Quebec. Transforming environments around schools to promote healthy eating includes modifying zoning regulations that restrict access to fast-food outlets around schools.

  16. Junk Food Marketing on Instagram: Content Analysis.

    Science.gov (United States)

    Vassallo, Amy Jo; Kelly, Bridget; Zhang, Lelin; Wang, Zhiyong; Young, Sarah; Freeman, Becky

    2018-06-05

    Omnipresent marketing of processed foods is a key driver of dietary choices and brand loyalty. Market data indicate a shift in food marketing expenditures to digital media, including social media. These platforms have greater potential to influence young people, given their unique peer-to-peer transmission and youths' susceptibility to social pressures. The aim of this study was to investigate the frequency of images and videos posted by the most popular, energy-dense, nutrient-poor food and beverage brands on Instagram and the marketing strategies used in these images, including any healthy choice claims. A content analysis of 15 accounts was conducted, using 12 months of Instagram posts from March 15, 2015, to March 15, 2016. A pre-established hierarchical coding guide was used to identify the primary marketing strategy of each post. Each brand used 6 to 11 different marketing strategies in their Instagram accounts; however, they often adhered to an overall theme such as athleticism or relatable consumers. There was a high level of branding, although not necessarily product information on all accounts, and there were very few health claims. Brands are using social media platforms such as Instagram to market their products to a growing number of consumers, using a high frequency of targeted and curated posts that manipulate consumer emotions rather than present information about their products. Policy action is needed that better reflects the current media environment. Public health bodies also need to engage with emerging media platforms and develop compelling social counter-marketing campaigns. ©Amy Jo Vassallo, Bridget Kelly, Lelin Zhang, Zhiyong Wang, Sarah Young, Becky Freeman. Originally published in JMIR Public Health and Surveillance (http://publichealth.jmir.org), 05.06.2018.

  17. Size Matters, if you Control Your Junk

    DEFF Research Database (Denmark)

    Asness, Cliff; Frazzini, Andrea; Israel, Ronen

    The size premium has been challenged along many fronts: it has a weak historical record, varies significantly over time, in particular weakening after its discovery, is concentrated among microcap stocks, resides predominantly in January, is not present for non-price based measures of size, is weak...... emerges, which is: stable through time, robust to specification, more consistent across seasons and markets, not concentrated in microcaps, robust to non-price based measures of size, and not captured by an illiquidity premium. These results are replicated in 30 different industries and in 24 different...... internationally, and is argued to be subsumed by proxies for illiquidity. We find, however, that these challenges are systematically dismantled when controlling for the quality, or its inverse “junk”, of a firm. Across a wide variety of quality measures proposed in the literature a significant size premium...

  18. [Junk food revolution or the cola colonization].

    Science.gov (United States)

    Horinger, P; Imoberdorf, R

    2000-03-01

    In ancient times, the main problem was to get food. Nowadays the difficulty is to decide for or against some foodstuff. In industrialized countries, this abundance led to the fact that people eat differently from what they should. Traditional populations were subject to periods of feast and famine. Those with a metabolism which stored energy with high energetic efficiency had a survival advantage. This is called the 'thrifty' genotype hypothesis. With the secured supply of calories, coupled with a sedentary lifestyle, the thrifty genotype becomes disadvantageous, causing obesity. Industrialization or 'cola-colonization' also leads to a dramatic increase in obesity and non-insulin dependent diabetes mellitus in developing countries. The spread of fast food restaurants all over the world has changed modern nutrition fundamentally. Influence begins early in childhood. Advertising concentrates on the selling of image over substance. However, fast food contains high levels of fat, especially trans fatty acids. Higher consumption of trans fatty acids was associated with a higher incidence of and mortality from coronary heart disease.

  19. Irradiated foodstuff: atom, junk-food and globalization

    International Nuclear Information System (INIS)

    Azam, Genevieve; Berlan, Jean-Pierre; Desbordes, Roland; Dufour, Francois; Fievet, Yann; Folliard, Thierry; Gallais, Veronique; Hauter, Wenonah; Jacquiau, Christian; Kastler, Guy; Lannoye, Paul; Le Goff, Lylian; Le Rohellec, Catherine; Louchard, Olivier; Marechal, Gilles; Nicolas, Yveline; Remesy, Christian; Trouve, Aurelie; Veillerette, Francois

    2008-01-01

    Food irradiation is officially presented as an ideal technology at the service of worldwide health safety and as an alternative to chemical processing of foodstuff. It is first of all a multi-usage technology for the preservation, disinfestation, ripening slowing down, and germination inhibition of products which serves the interests of multinational companies of the agriculture and food industry. According to the authors, it is also an instrument for the globalization of foodstuff trade encouraged by the international institutions and by some governments. The book stresses on the health, socio-economic and environmental risks of this technology: vitamins loss, carcinogenesis, mutagenesis, impact on local employment and economy, risks linked with the use of irradiation devices etc

  20. Hong Kong Junk: Plague and the Economy of Chinese Things.

    Science.gov (United States)

    Peckham, Robert

    2016-01-01

    Histories of the Third Plague Pandemic, which diffused globally from China in the 1890s, have tended to focus on colonial efforts to regulate the movement of infected populations, on the state's draconian public health measures, and on the development of novel bacteriological theories of disease causation. In contrast, this article focuses on the plague epidemic in Hong Kong and examines colonial preoccupations with Chinese "things" as sources of likely contagion. In the 1890s, laboratory science invested plague with a new identity as an object to be collected, cultivated, and depicted in journals. At the same time, in the increasingly vociferous anti-opium discourse, opium was conceived as a contagious Chinese commodity: a plague. The article argues that rethinking responses to the plague through the history of material culture can further our understanding of the political consequences of disease's entanglement with economic and racial categories, while demonstrating the extent to which colonial agents "thought through things."

  1. Junk-Time Junkies: An Emerging Addiction among Students.

    Science.gov (United States)

    Soper, W. Barlow; Miller, Mark J.

    1983-01-01

    Discusses video games as an emerging addiction among students. Describes the appeal of the games, their impact on students, and measures passed in some cities to curb adolescent involvement. Counselors must be prepared to anticipate and ameliorate potentially negative side effects. (JAC)

  2. Digital junk: food and beverage marketing on Facebook.

    Science.gov (United States)

    Freeman, Becky; Kelly, Bridget; Baur, Louise; Chapman, Kathy; Chapman, Simon; Gill, Tim; King, Lesley

    2014-12-01

    We assessed the amount, reach, and nature of energy-dense, nutrient-poor (EDNP) food and beverage marketing on Facebook. We conducted a content analysis of the marketing techniques used by the 27 most popular food and beverage brand Facebook pages in Australia. We coded content across 19 marketing categories; data were collected from the day each page launched (mean = 3.65 years of activity per page). We analyzed 13 international pages and 14 Australian-based brand pages; 4 brands (Subway, Coca-Cola, Slurpee, Maltesers) had both national and international pages. Pages widely used marketing features unique to social media that increase consumer interaction and engagement. Common techniques were competitions based on user-generated content, interactive games, and apps. Four pages included apps that allowed followers to place an order directly through Facebook. Adolescent and young adult Facebook users appeared most receptive to engaging with this content. By using the interactive and social aspects of Facebook to market products, EDNP food brands capitalize on users' social networks and magnify the reach and personal relevance of their marketing messages.

  3. Digital Junk: Food and Beverage Marketing on Facebook

    Science.gov (United States)

    Freeman, Becky; Kelly, Bridget; Baur, Louise; Chapman, Kathy; Chapman, Simon; Gill, Tim; King, Lesley

    2014-01-01

    Objectives. We assessed the amount, reach, and nature of energy-dense, nutrient-poor (EDNP) food and beverage marketing on Facebook. Methods. We conducted a content analysis of the marketing techniques used by the 27 most popular food and beverage brand Facebook pages in Australia. We coded content across 19 marketing categories; data were collected from the day each page launched (mean = 3.65 years of activity per page). Results. We analyzed 13 international pages and 14 Australian-based brand pages; 4 brands (Subway, Coca-Cola, Slurpee, Maltesers) had both national and international pages. Pages widely used marketing features unique to social media that increase consumer interaction and engagement. Common techniques were competitions based on user-generated content, interactive games, and apps. Four pages included apps that allowed followers to place an order directly through Facebook. Adolescent and young adult Facebook users appeared most receptive to engaging with this content. Conclusions. By using the interactive and social aspects of Facebook to market products, EDNP food brands capitalize on users’ social networks and magnify the reach and personal relevance of their marketing messages. PMID:25322294

  4. Gambling advocacy: lessons from tobacco, alcohol and junk food.

    Science.gov (United States)

    Thomas, Samantha L; David, Jennifer; Randle, Melanie; Daube, Mike; Senior, Kate

    2016-06-01

    To explore the attitudes and opinions of public health experts in gambling and related unhealthy commodity industries towards the tactics used by the gambling industry to prevent reform and the advocacy responses to these tactics. In-depth interviews (30-60 minutes) with a convenience sample of 15 public health experts and stakeholders with a public health approach to gambling (n=10), or other unhealthy commodity industries (food, alcohol, tobacco, n=5). Participants described the influences of political lobbying and donations on public policy, and industry framing of problem gambling as an issue of personal responsibility. Industry funding of, and influence over, academic research was considered to be one of the most effective industry tactics to resist reform. Participants felt there was a need to build stronger coalitions and collaborations between independent academics, and to improve the utilisation of media to more effectively shift perceptions of gambling harm away from the individual and towards the product. Gambling industry tactics are similar to the tactics of other unhealthy commodity industries. However, advocacy initiatives to counter these tactics in gambling are less developed than in other areas. The formation of national public health coalitions, as well as a strong evidence base regarding industry tactics, will help to strengthen advocacy initiatives. © 2015 Public Health Association of Australia.

  5. Got junk? The federal role in regulating "competitive" foods.

    Science.gov (United States)

    Salinsky, Eileen

    2009-12-11

    A wide variety of food and beverage items are available in schools in addition to the school meals provided through the National School Lunch Program and School Breakfast Program. A long-standing source of controversy, the need for stronger federal restrictions on foods that compete with school meals is again under debate. This issue brief examines the availability and consumption of competitive foods, explores the regulation of these foods at the federal level, considers trends in state and local restrictions, and summarizes perceived barriers to improving the nutritional quality of competitive food options.

  6. Irradiated foodstuff: atom, junk-food and globalization; Aliments irradies: Atome, malbouffe et mondialisation

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Genevieve; Berlan, Jean-Pierre; Desbordes, Roland; Dufour, Francois; Fievet, Yann; Folliard, Thierry; Gallais, Veronique; Hauter, Wenonah; Jacquiau, Christian; Kastler, Guy; Lannoye, Paul; Le Goff, Lylian; Le Rohellec, Catherine; Louchard, Olivier; Marechal, Gilles; Nicolas, Yveline; Remesy, Christian; Trouve, Aurelie; Veillerette, Francois

    2008-07-01

    Food irradiation is officially presented as an ideal technology at the service of worldwide health safety and as an alternative to chemical processing of foodstuff. It is first of all a multi-usage technology for the preservation, disinfestation, ripening slowing down, and germination inhibition of products which serves the interests of multinational companies of the agriculture and food industry. According to the authors, it is also an instrument for the globalization of foodstuff trade encouraged by the international institutions and by some governments. The book stresses on the health, socio-economic and environmental risks of this technology: vitamins loss, carcinogenesis, mutagenesis, impact on local employment and economy, risks linked with the use of irradiation devices etc

  7. Space Junk Norms: US Advantages in Creating a Debris Reducing Outer Space Norm

    Science.gov (United States)

    2011-05-01

    overfishing concerns related to state interests began as early as the sixteenth century. The second Truman proclamation highlighted how... overfishing just beyond a coastal states territorial sea. Again, coastal states did not reject the US proclamation, but instead moved to clarify it with

  8. Junk DNA enhances pEI-based non-viral gene delivery

    NARCIS (Netherlands)

    Gaal, E.V.B. van; Oosting, R.S.; Hennink, W.E.; Crommelin, D.J.A.; Mastrobattista, E.

    Gene therapy aims at delivering exogenous DNA into the nuclei of target cells to establish expression of a therapeutic protein. Non-viral gene delivery is examined as a safer alternative to viral approaches, but is presently characterized by a low efficiency. In the past years several non-viral

  9. Junk DNA and the long non-coding RNA twist in cancer genetics

    NARCIS (Netherlands)

    H. Ling (Hui); K. Vincent; M. Pichler; R. Fodde (Riccardo); I. Berindan-Neagoe (Ioana); F.J. Slack (Frank); G.A. Calin (George)

    2015-01-01

    textabstractThe central dogma of molecular biology states that the flow of genetic information moves from DNA to RNA to protein. However, in the last decade this dogma has been challenged by new findings on non-coding RNAs (ncRNAs) such as microRNAs (miRNAs). More recently, long non-coding RNAs

  10. Protecting Young People From Junk Food Advertising: Implications of Psychological Research for First Amendment Law

    Science.gov (United States)

    Harris, Jennifer L.; Graff, Samantha K.

    2012-01-01

    In the United States, one third of children and adolescents are overweight or obese, yet food and beverage companies continue to target them with advertising for products that contribute to this obesity crisis. When government restrictions on such advertising are proposed, the constitutional commercial speech doctrine is often invoked as a barrier to action. We explore incongruities between the legal justifications for the commercial speech doctrine and the psychological research on how food advertising affects young people. A proper interpretation of the First Amendment should leave room for regulations to protect young people from advertising featuring calorie-dense, nutrient-poor foods and beverages. PMID:22390435

  11. Protecting young people from junk food advertising: implications of psychological research for First Amendment law.

    Science.gov (United States)

    Harris, Jennifer L; Graff, Samantha K

    2012-02-01

    In the United States, one third of children and adolescents are overweight or obese, yet food and beverage companies continue to target them with advertising for products that contribute to this obesity crisis. When government restrictions on such advertising are proposed, the constitutional commercial speech doctrine is often invoked as a barrier to action. We explore incongruities between the legal justifications for the commercial speech doctrine and the psychological research on how food advertising affects young people. A proper interpretation of the First Amendment should leave room for regulations to protect young people from advertising featuring calorie-dense, nutrient-poor foods and beverages.

  12. Mechanism change in a simulation of peer review: from junk support to elitism.

    Science.gov (United States)

    Paolucci, Mario; Grimaldo, Francisco

    2014-01-01

    Peer review works as the hinge of the scientific process, mediating between research and the awareness/acceptance of its results. While it might seem obvious that science would regulate itself scientifically, the consensus on peer review is eroding; a deeper understanding of its workings and potential alternatives is sorely needed. Employing a theoretical approach supported by agent-based simulation, we examined computational models of peer review, performing what we propose to call redesign , that is, the replication of simulations using different mechanisms . Here, we show that we are able to obtain the high sensitivity to rational cheating that is present in literature. In addition, we also show how this result appears to be fragile against small variations in mechanisms. Therefore, we argue that exploration of the parameter space is not enough if we want to support theoretical statements with simulation, and that exploration at the level of mechanisms is needed. These findings also support prudence in the application of simulation results based on single mechanisms, and endorse the use of complex agent platforms that encourage experimentation of diverse mechanisms.

  13. Adolescent girls' most common source of junk food away from home.

    Science.gov (United States)

    Cohen, Deborah A; Ghosh-Dastidar, Bonnie; Beckman, Robin; Lytle, Leslie; Elder, John; Pereira, Mark A; Veblen Mortenson, Sara; Pickrel, Julie; Conway, Terry L

    2012-09-01

    Contextual factors associated with adolescent girls' dietary behaviors could inform future interventions to improve diet. High school girls completed a 7-day diary, recording all trips made. In places other than home or school they recorded the food eaten. Girls made an average of 11.4 trips per week other than to home or school. Snacks high in solid oils, fats and added sugars (SOFAS) were frequently consumed. Girls reported eating an average of 3.5 servings per week of snacks high in SOFAS at someone else's house compared to 3.0 servings per week at retail food outlets. Findings demonstrate that low nutrient foods are ubiquitous and efforts should be made to reduce their availability in multiple settings. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Here's Why Junk Food Still Is on Sale at Some Schools.

    Science.gov (United States)

    Nolte, M. Chester

    1984-01-01

    A 1983 federal appeals court decision says the Secretary of Agriculture cannot establish time and place restrictions on the sale of snack items in schools. If snack items are to be banned from schools, the School Lunch Act must be reworded. (MD)

  15. Where do food desert residents buy most of their junk food? Supermarkets.

    Science.gov (United States)

    Vaughan, Christine A; Cohen, Deborah A; Ghosh-Dastidar, Madhumita; Hunter, Gerald P; Dubowitz, Tamara

    2017-10-01

    To examine where residents in an area with limited access to healthy foods (an urban food desert) purchased healthier and less healthy foods. Food shopping receipts were collected over a one-week period in 2013. These were analysed to describe where residents shopped for food and what types of food they bought. Two low-income, predominantly African-American neighbourhoods with limited access to healthy foods in Pittsburgh, PA, USA. Two hundred and ninety-three households in which the primary food shoppers were predominantly female (77·8 %) and non-Hispanic black (91·1 %) adults. Full-service supermarkets were by far the most common food retail outlet from which food receipts were returned and accounted for a much larger proportion (57·4 %) of food and beverage expenditures, both healthy and unhealthy, than other food retail outlets. Although patronized less frequently, convenience stores were notable purveyors of unhealthy foods. Findings highlight the need to implement policies that can help to decrease unhealthy food purchases in full-service supermarkets and convenience stores and increase healthy food purchases in convenience stores.

  16. The American Education Diet: Can U.S. Students Survive on Junk Food?

    Science.gov (United States)

    DeSchryver, Dave

    U.S. student scores in science compare unfavorably with those of other nations, and other standardized test scores by U.S. students are also comparatively lower. Polls of parents indicate dissatisfaction with U.S. education. College teachers and employers feel that high school graduates are weak in skills. This document offers negative perceptions…

  17. Effects of nicotine on body weight in rats with access to "junk" foods.

    Science.gov (United States)

    Grunberg, N E; Popp, K A; Winders, S E

    1988-01-01

    The present experiment examined effects of nicotine on body weight of male and female rats when Oreo cookies, potato chips, laboratory chow, and water were available. Body weight and eating behavior were measured for 17-day periods before, during, and after nicotine or saline administration. There was an inverse relationship between nicotine and body weight. These effects were paralleled by changes in consumption of sweet foods. There were no effects of nicotine on salty or bland food consumption. Excessive gains in body weight after cessation of nicotine administration were greater for females than for males.

  18. Generalized Wideband Cyclic MUSIC

    Directory of Open Access Journals (Sweden)

    Zhang-Meng Liu

    2009-01-01

    Full Text Available The method of Spectral Correlation-Signal Subspace Fitting (SC-SSF fails to separate wideband cyclostationary signals with coherent second-order cyclic statistics (SOCS. Averaged Cyclic MUSIC (ACM method made up for the drawback to some degree via temporally averaging the cyclic cross-correlation of the array output. This paper interprets ACM from another perspective and proposes a new DOA estimation method by generalizing ACM for wideband cyclostationary signals. The proposed method successfully makes up for the aforementioned drawback of SC-SSF and obtains a more satisfying performance than ACM. It is also demonstrated that ACM is a simplified form of the proposed method when only a single spectral frequency is exploited, and the integration of the frequencies within the signal bandwidth helps the new method to outperform ACM.

  19. Identifying sources of children's consumption of junk food in Boston after-school programs, April-May 2011.

    Science.gov (United States)

    Kenney, Erica L; Austin, S Bryn; Cradock, Angie L; Giles, Catherine M; Lee, Rebekka M; Davison, Kirsten K; Gortmaker, Steven L

    2014-11-20

    Little is known about how the nutrition environment in after-school settings may affect children's dietary intake. We measured the nutritional quality of after-school snacks provided by programs participating in the National School Lunch Program or the Child and Adult Care Food Program and compared them with snacks brought from home or purchased elsewhere (nonprogram snacks). We quantified the effect of nonprogram snacks on the dietary intake of children who also received program-provided snacks during after-school time. Our study objective was to determine how different sources of snacks affect children's snack consumption in after-school settings. We recorded snacks served to and brought in by 298 children in 18 after-school programs in Boston, Massachusetts, on 5 program days in April and May 2011. We measured children's snack consumption on 2 program days using a validated observation protocol. We then calculated within-child change-in-change models to estimate the effect of nonprogram snacks on children's dietary intake after school. Nonprogram snacks contained more sugary beverages and candy than program-provided snacks. Having a nonprogram snack was associated with significantly higher consumption of total calories (+114.7 kcal, P < .001), sugar-sweetened beverages (+0.5 oz, P = .01), desserts (+0.3 servings, P < .001), and foods with added sugars (+0.5 servings; P < .001) during the snack period. On days when children brought their own after-school snack, they consumed more salty and sugary foods and nearly twice as many calories than on days when they consumed only program-provided snacks. Policy strategies limiting nonprogram snacks or setting nutritional standards for them in after-school settings should be explored further as a way to promote child health.

  20. Junk food advertising moderates the indirect effect of reward sensitivity and food consumption via the urge to eat.

    Science.gov (United States)

    Kidd, Chloe; Loxton, Natalie J

    2018-05-01

    The current study aimed to identify how underlying individual differences increases vulnerability to television food advertising. In particular, this study examined how reward sensitivity, a biologically-based predisposition to approach rewards (such as appetitive foods) in the environment, influenced participants' vulnerability to television food advertising and subsequent food consumption. Ninety-eight participants were randomly assigned to a cue condition (food cues versus non-food cues) and then viewed a 30 min documentary interrupted by advertising featuring a mix of food and neutral advertising (food cue condition) or only neutral advertising (non-food cue condition). Participants' reward sensitivity, approach motivation measured as urge to eat, and food consumption were recorded. Moderated mediation regression analyses revealed the positive association between reward sensitivity and food consumption was mediated by an increase in urge to eat, but only when participants were exposed to food advertising. These findings suggest heightened reward sensitivity, exposure to appetitive food cues, and approach motivation are key interacting mechanisms that may lead to maladaptive eating behaviours. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Junk food or genuine nourishment: The nutritional value of some of South African fast-food chains

    Directory of Open Access Journals (Sweden)

    R.C. Van den Honert

    2003-12-01

    Full Text Available Integer programming is used to test the nutritional completeness of two fast-food chains operating in South Africa. McDonald's and Kentucky Fried Chicken. It is shown that a fully nutritional and varied daily diet can be made up from McDonald's menu items, but the same is not true for Kentucky Fried Chicken. This exercise is highly suited to introduce students to mathematical programming: skills learned include formulating mathematical programming problems, mastering linear programming software and exploring the Internet for relevant data.

  2. Evidence-Based versus Junk-Based Evaluation Research: Some Lessons from 35 Years of the Evaluation Review

    Science.gov (United States)

    Berk, Richard

    2011-01-01

    Along with the late Howard Freeman, Richard Berk was a founding editor of "Evaluation Review" (then "Evaluation Quarterly") in 1977. He resigned as editor of this journal at the end of 2010. In this article, he reflects on his experiences. (Contains 3 notes.)

  3. Contexts paired with junk food impair goal-directed behaviour in rats: implications for decision making in obesogenic environments

    Directory of Open Access Journals (Sweden)

    Michael D. Kendig

    2016-11-01

    Full Text Available The high prevalence of obesity and related metabolic diseases calls for greater understanding of the factors that drive excess energy intake. Calorie-dense palatable foods are readily available and often are paired with highly salient environmental cues. These cues can trigger food-seeking and consumption in the absence of hunger. Here we examined the effects of palatable food-paired environmental cues on control of instrumental food-seeking behaviour. In Experiment 1, adult male rats received exposures to one context containing three ‘junk’ foods (JF context and another containing chow (Chow context. Next, rats were food-deprived and trained to perform instrumental responses (lever-press for two novel food rewards in a third, distinct context. Contextual influences on flexible control of food-seeking behaviour were then assessed by outcome devaluation tests held in the JF, chow, and training contexts. Devaluation was achieved using specific satiety and test order was counterbalanced. Rats exhibited goal-directed control over behaviour when tested in the training and chow-paired contexts. Notably, performance was habitual (insensitive to devaluation when tested in the JF context. In Experiment 2 we tested whether the impairment found in the JF context could be ameliorated by the presentation of a discrete auditory cue paired with the chow context, relative to a second cue paired with the JF context. Consistent with the results of Experiment 1, the devaluation effect was not significant when rats were tested in the JF context with the JF cue. However, presenting the chow cue increased the impact of the devaluation treatment leading to a robust devaluation effect. Further tests confirmed that performance in the chow context was goal-directed and that sensory-specific satiety in the JF context was intact. These results show that environments paired with palatable foods can impair goal-directed control over food-seeking behaviour, but that this deficit was improved by a cue paired with chow. This has promising implications for assisting individuals in controlling their eating behaviour in environments designed to dysregulate it.

  4. How avatar customizability affects children's arousal and subjective presence during junk food-sponsored online video games.

    Science.gov (United States)

    Bailey, Rachel; Wise, Kevin; Bolls, Paul

    2009-06-01

    The purpose of this study was to determine how children cognitively and emotionally process interactive marketing of snack food products in advergames. Children (N = 30) aged 10 to 12 were asked to play advergames with (a) avatars that were assigned to them, (b) avatars chosen from a pool, and (c) self-designed avatars. The children's skin conductance levels were collected during play. After gameplay, at each customization level, self-reported presence was collected. The results of this study indicate that customization of game avatars can affect both subjective feelings of presence and psychophysiological indicators of emotion during gameplay, which may make the gameplay experience more enjoyable. This may have implications for game sponsors and producers. Self-reported presence had no effect on psychophysiological indicators of emotion during gameplay. Implications of this finding and limitations of this study are discussed.

  5. Identifying Sources of Children’s Consumption of Junk Food in Boston After-School Programs, April–May 2011

    Science.gov (United States)

    Austin, S. Bryn; Cradock, Angie L.; Giles, Catherine M.; Lee, Rebekka M.; Davison, Kirsten K.; Gortmaker, Steven L.

    2014-01-01

    Introduction Little is known about how the nutrition environment in after-school settings may affect children’s dietary intake. We measured the nutritional quality of after-school snacks provided by programs participating in the National School Lunch Program or the Child and Adult Care Food Program and compared them with snacks brought from home or purchased elsewhere (nonprogram snacks). We quantified the effect of nonprogram snacks on the dietary intake of children who also received program-provided snacks during after-school time. Our study objective was to determine how different sources of snacks affect children’s snack consumption in after-school settings. Methods We recorded snacks served to and brought in by 298 children in 18 after-school programs in Boston, Massachusetts, on 5 program days in April and May 2011. We measured children’s snack consumption on 2 program days using a validated observation protocol. We then calculated within-child change-in-change models to estimate the effect of nonprogram snacks on children’s dietary intake after school. Results Nonprogram snacks contained more sugary beverages and candy than program-provided snacks. Having a nonprogram snack was associated with significantly higher consumption of total calories (+114.7 kcal, P snack period. Conclusion On days when children brought their own after-school snack, they consumed more salty and sugary foods and nearly twice as many calories than on days when they consumed only program-provided snacks. Policy strategies limiting nonprogram snacks or setting nutritional standards for them in after-school settings should be explored further as a way to promote child health. PMID:25412028

  6. "Most of Them Are Junk Food but We Did Put Fruit on There and We Have Water"

    Science.gov (United States)

    Waddingham, Suzanne; Stevens, Stella; Macintyre, Kate; Shaw, Kelly

    2015-01-01

    Purpose: The Australian Dietary Guidelines support good health and disease prevention. Children with healthy eating habits established early in life have been shown to continue these habits into adulthood compared with those children who have poor eating habits in their younger years. The nutritional intake of many Australian children is not in…

  7. Wideband amplifier design

    CERN Document Server

    Hollister, Allen L

    2007-01-01

    In this book, the theory needed to understand wideband amplifier design using the simplest models possible will be developed. This theory will be used to develop algebraic equations that describe particular circuits used in high frequency design so that the reader develops a ""gut level"" understanding of the process and circuit. SPICE and Genesys simulations will be performed to show the accuracy of the algebraic models. By looking at differences between the algebraic equations and the simulations, new algebraic models will be developed that include parameters originally left out of the model

  8. Wideband CMOS receivers

    CERN Document Server

    Oliveira, Luis

    2015-01-01

    This book demonstrates how to design a wideband receiver operating in current mode, in which the noise and non-linearity are reduced, implemented in a low cost single chip, using standard CMOS technology.  The authors present a solution to remove the transimpedance amplifier (TIA) block and connect directly the mixer’s output to a passive second-order continuous-time Σ∆ analog to digital converter (ADC), which operates in current-mode. These techniques enable the reduction of area, power consumption, and cost in modern CMOS receivers.

  9. Wideband Piezomagnetoelastic Vibration Energy Harvesting

    DEFF Research Database (Denmark)

    Lei, Anders; Thomsen, Erik Vilain

    2014-01-01

    This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation...... is achieved by placing the cantilever in a magnetic field induced by either one or two magnets located oppositely of the cantilever. The attraction force created by the magnetic field and iron foils introduces a mechanical force in opposite direction of the cantilevers restoring force causing a spring...

  10. Maritime wideband communication networks video transmission scheduling

    CERN Document Server

    Yang, Tingting

    2014-01-01

    This Springer Brief covers emerging maritime wideband communication networks and how they facilitate applications such as maritime distress, urgency, safety and general communications. It provides valuable insight on the data transmission scheduling and protocol design for the maritime wideband network. This brief begins with an introduction to maritime wideband communication networks including the architecture, framework, operations and a comprehensive survey on current developments. The second part of the brief presents the resource allocation and scheduling for video packet transmission wit

  11. Wideband 4-diode sampling circuit

    Science.gov (United States)

    Wojtulewicz, Andrzej; Radtke, Maciej

    2016-09-01

    The objective of this work was to develop a wide-band sampling circuit. The device should have the ability to collect samples of a very fast signal applied to its input, strengthen it and prepare for further processing. The study emphasizes the method of sampling pulse shaping. The use of ultrafast pulse generator allows sampling signals with a wide frequency spectrum, reaching several gigahertzes. The device uses a pulse transformer to prepare symmetrical pulses. Their final shape is formed with the help of the step recovery diode, two coplanar strips and Schottky diode. Made device can be used in the sampling oscilloscope, as well as other measurement system.

  12. Wideband feedback system prototype validation

    CERN Document Server

    Li, K; Bjorsvik, E; Fox, J; Hofle, W; Kotzian, G; Rivetta, C; Salvant, B; Turgut, O

    2017-01-01

    A wideband feedback demonstrator system has been de-veloped in collaboration with US-LARP under the joint lead-ership of CERN and SLAC. The system includes widebandkicker structures and amplifiers along with a fast digital re-configurable system up to 4 GS/s for single bunch and multibunch control. Most of the components have been installedin recent years and have been put into operation to test bothintra-bunch damping and individual bunch control in a multibunch train. In this note we report on the MD program,procedure and key findings that were made with this systemin the past year.

  13. Introduction to Ultra Wideband for Wireless Communications

    DEFF Research Database (Denmark)

    Nikookar, Homayoun; Prasad, Ramjee

    wireless channels, interference, signal processing as well as applications and standardization activities are addressed. Introduction to Ultra Wideband for Wireless Communications provides easy-to-understand material to (graduate) students and researchers working in the field of commercial UWB wireless......Ultra Wideband (UWB) Technology is the cutting edge technology for wireless communications with a wide range of applications. In Introduction to Ultra Wideband for Wireless Communications UWB principles and technologies for wireless communications are explained clearly. Key issues such as UWB...... communications. Due to tutorial nature of the book it can also be adopted as a textbook on the subject in the Telecommunications Engineering curriculum. Problems at the end of each chapter extend the reader's understanding of the subject. Introduction to Ultra Wideband for Wireless Communications will aslo...

  14. Ultra wideband antennas design, methodologies, and performance

    CERN Document Server

    Galvan-Tejada, Giselle M; Jardón Aguilar, Hildeberto

    2015-01-01

    Ultra Wideband Antennas: Design, Methodologies, and Performance presents the current state of the art of ultra wideband (UWB) antennas, from theory specific for these radiators to guidelines for the design of omnidirectional and directional UWB antennas. Offering a comprehensive overview of the latest UWB antenna research and development, this book:Discusses the developed theory for UWB antennas in frequency and time domainsDelivers a brief exposition of numerical methods for electromagnetics oriented to antennasDescribes solid-planar equivalen

  15. A wideband software reconfigurable modem

    Science.gov (United States)

    Turner, J. H., Jr.; Vickers, H.

    A wideband modem is described which provides signal processing capability for four Lx-band signals employing QPSK, MSK and PPM waveforms and employs a software reconfigurable architecture for maximum system flexibility and graceful degradation. The current processor uses a 2901 and two 8086 microprocessors per channel and performs acquisition, tracking, and data demodulation for JITDS, GPS, IFF and TACAN systems. The next generation processor will be implemented using a VHSIC chip set employing a programmable complex array vector processor module, a GP computer module, customized gate array modules, and a digital array correlator. This integrated processor has application to a wide number of diverse system waveforms, and will bring the benefits of VHSIC technology insertion into avionic antijam communications systems.

  16. 'We've Got Some Underground Business Selling Junk Food': Qualitative Evidence of the Unintended Effects of English School Food Policies

    OpenAIRE

    Fletcher, A.; Jamal, Farah; Fitzgerald-Yau, N.; Bonell, C.

    2013-01-01

    Drawing on two qualitative studies, we report evidence of pervasive black markets in confectionery, ‘junk’ food and energy drinks in English secondary schools. Data were \\ud collected at six schools through focus groups and interviews with students (n= 149) and staff (n= 36), and direct observations. Supermarkets, new technologies and teachers’ narrow focus on attainment have enabled these ‘underground businesses’ to emerge following increased\\ud state regulation of school food and drink prov...

  17. Nourishing change. Partnership enlists dozens of hospitals to put healthier food on their menus and kick junk food out of the cafeteria.

    Science.gov (United States)

    Lee, Jaimy

    2012-10-08

    More than 150 hospitals have signed on to the Partnership for a Healthier America's push to ditch the deep-fat fryer in their cafeterias and bulk up on fruit and veggies. "Our focus is to ensure that if people want to make a healthy choice, they can," says Larry Soler, left, president and CEO of the partnership, which is working to reduce childhood obesity.

  18. Are white storks addicted to junk food? Impacts of landfill use on the movement and behaviour of resident white storks (Ciconia ciconia) from a partially migratory population.

    Science.gov (United States)

    Gilbert, Nathalie I; Correia, Ricardo A; Silva, João Paulo; Pacheco, Carlos; Catry, Inês; Atkinson, Philip W; Gill, Jenny A; Franco, Aldina M A

    2016-01-01

    The migratory patterns of animals are changing in response to global environmental change with many species forming resident populations in areas where they were once migratory. The white stork (Ciconia ciconia) was wholly migratory in Europe but recently guaranteed, year-round food from landfill sites has facilitated the establishment of resident populations in Iberia. In this study 17 resident white storks were fitted with GPS/GSM data loggers (including accelerometer) and tracked for 9.1 ± 3.7 months to quantify the extent and consistency of landfill attendance by individuals during the non-breeding and breeding seasons and to assess the influence of landfill use on daily distances travelled, percentage of GPS fixes spent foraging and non-landfill foraging ranges. Resident white storks used landfill more during non-breeding (20.1 % ± 2.3 of foraging GPS fixes) than during breeding (14.9 % ± 2.2). Landfill attendance declined with increasing distance between nest and landfill in both seasons. During non-breeding a large percentage of GPS fixes occurred on the nest throughout the day (27 % ± 3.0 of fixes) in the majority of tagged storks. This study provides first confirmation of year-round nest use by resident white storks. The percentage of GPS fixes on the nest was not influenced by the distance between nest and the landfill site. Storks travelled up to 48.2 km to visit landfills during non-breeding and a maximum of 28.1 km during breeding, notably further than previous estimates. Storks nesting close to landfill sites used landfill more and had smaller foraging ranges in non-landfill habitat indicating higher reliance on landfill. The majority of non-landfill foraging occurred around the nest and long distance trips were made specifically to visit landfill. The continuous availability of food resources on landfill has facilitated year-round nest use in white storks and is influencing their home ranges and movement behaviour. White storks rely on landfill sites for foraging especially during the non-breeding season when other food resources are scarcer and this artificial food supplementation probably facilitated the establishment of resident populations. The closure of landfills, as required by EU Landfill Directives, will likely cause dramatic impacts on white stork populations.

  19. "We never ate like that, not fast food, or junk foods": accounts of changing maternal diet in a tourist community in rural Costa Rica.

    Science.gov (United States)

    Cantor, Allison; Peña, Jenny; Himmelgreen, David

    2013-01-01

    This investigation examines maternal diet in rural Costa Rica in the context of recent political economic changes. Results show that increased availability of non-local food items, (i.e., pizza and processed foods) has influenced maternal dietary choices. Information pathways, which have traditionally provided women with knowledge about maternal diet from family members, are also shifting. Younger women turn to the local clinic and the media for information about maternal diet, and traditional practices, such as cuarentena (40-day postpartum period), are no longer being observed. Changing practices may be linked with shifting information pathways, as well as self-reported weight gain among women.

  20. Socioeconomic indicators and frequency of traditional food, junk food, and fruit and vegetable consumption amongst Inuit adults in the Canadian Arctic.

    Science.gov (United States)

    Hopping, B N; Erber, E; Mead, E; Sheehy, T; Roache, C; Sharma, S

    2010-10-01

    Increasing consumption of non-nutrient-dense foods (NNDF), decreasing consumption of traditional foods (TF) and low consumption of fruit and vegetables (FV) may contribute to increasing chronic disease rates amongst Inuit. The present study aimed to assess the daily frequency and socioeconomic and demographic factors influencing consumption of TF, FV and NNDF amongst Inuit adults in Nunavut, Canada. Using a cross-sectional study design and random household sampling in three communities in Nunavut, a food frequency questionnaire developed for the population was used to assess frequency of NNDF, TF and FV consumption amongst Inuit adults. Socioeconomic status (SES) was assessed by education level, ownership of items in working condition, and whether or not people in the household were employed or on income support. Mean frequencies of daily consumption were compared across gender and age groups, and associations with socioeconomic indicators were analysed using logistic regression. Two hundred and eleven participants (36 men, 175 women; mean (standard deviation) ages 42.1 (15.0) and 42.2 (13.2) years, respectively; response rate 69-93%) completed the study. Mean frequencies of consumption for NNDF, TF and FV were 6.3, 1.9 and 1.6 times per day, respectively. On average, participants ≤50 years consumed NNDF (P=0.003) and FV (P=0.01) more frequently and TF (P=0.01) less frequently than participants >50 years. Education was positively associated with FV consumption and negatively associated with TF consumption. Households on income support were more likely to consume TF and NNDF. These results support the hypothesis that the nutrition transition taking place amongst Inuit in Nunavut results in elevated consumption of NNDF compared with TF and FV. © 2010 The Authors. Journal compilation © 2010 The British Dietetic Association Ltd.

  1. Wideband feeds for the upgraded GMRT

    International Nuclear Information System (INIS)

    Bandari, Hanumanth Rao; Sankarasubramanian, G; Kumar, A Praveen

    2013-01-01

    This paper describes the existing feeds in use at the GMRT Observatory and details the ongoing development of next generation wideband feeds for the upgraded GMRT. The existing feeds include: feed with folded thick dipoles (for 150 MHz), dipole-disc feed (for 325 MHz), dual-band coaxial feed (for 233 MHZ and 610 MHz), and corrugated horn feed (for 1400–1450 MHz). The new broadband feeds covered in this paper are: cone-dipole feeds for 250–500 and 500–1000 MHz, wideband horn feed for 550–900 MHz, and dual ring feed for 130–260 MHz. Design techniques and performance results for these are described.

  2. Ultra-wideband radar sensors and networks

    Science.gov (United States)

    Leach, Jr., Richard R; Nekoogar, Faranak; Haugen, Peter C

    2013-08-06

    Ultra wideband radar motion sensors strategically placed in an area of interest communicate with a wireless ad hoc network to provide remote area surveillance. Swept range impulse radar and a heart and respiration monitor combined with the motion sensor further improves discrimination.

  3. A wideband absorber for television studios

    Science.gov (United States)

    Baird, M. D. M.

    The acoustic treatment in BBC television has taken various forms to date, all of which have been relatively expensive, some of which provide inadequate absorption. An investigation has been conducted into the possibilities of producing a new type of wideband absorber which would be more economic, also taking installation time into account, than earlier designs. This Report describes the absorption coefficient measurements made on various combinations of materials, from which a wideband sound absorber has been developed. The absorber works efficiently between 50 Hz and 10 kHz, is simple and easy to construct using readily available materials, and is fire resistant. The design lends itself, if necessary, to on-site fine tuning, and savings in the region of 50 percent can be achieved in terms of cost and space with respect to previous designs.

  4. Super wideband characteristics of monopolar patch antenna

    Directory of Open Access Journals (Sweden)

    Xi Chen

    2013-12-01

    Full Text Available A simple method of acquiring super wideband characteristics for monopolar patch antenna is proposed. Through adopting a modified cone as feeding and radiating structure, the monopolar patch antenna can reach the impedance bandwidth of more than 1:23.4 for voltage standing wave ratio (VSWR ≤ 2. In the whole operating band, the antenna has the like-monopole omnidirectional radiation patterns and the peak gains of 3.8–8.7 dB. Meanwhile, the height of the antenna is just 0.074λ(c, and the diameter of the radiated body is 0.205λ(c, which is smaller than other ultra-wideband omnidirectional antenna.

  5. Ultra-Wideband, Short Pulse Electromagnetics 9

    CERN Document Server

    Rachidi, Farhad; Kaelin, Armin; Sabath, Frank; UWB SP 9

    2010-01-01

    Ultra-wideband (UWB), short-pulse (SP) electromagnetics are now being used for an increasingly wide variety of applications, including collision avoidance radar, concealed object detection, and communications. Notable progress in UWB and SP technologies has been achieved by investigations of their theoretical bases and improvements in solid-state manufacturing, computers, and digitizers. UWB radar systems are also being used for mine clearing, oil pipeline inspections, archeology, geology, and electronic effects testing. Ultra-wideband Short-Pulse Electromagnetics 9 presents selected papers of deep technical content and high scientific quality from the UWB-SP9 Conference, which was held from July 21-25, 2008, in Lausanne, Switzerland. The wide-ranging coverage includes contributions on electromagnetic theory, time-domain computational techniques, modeling, antennas, pulsed-power, UWB interactions, radar systems, UWB communications, and broadband systems and components. This book serves as a state-of-the-art r...

  6. A Resistive Wideband Space Beam Splitter

    OpenAIRE

    Mahesh, Nivedita; Subrahmanyan, Ravi; Shankar, N. Udaya; Raghunathan, Agaram

    2014-01-01

    We present the design, construction and measurements of the electromagnetic performance of a wideband space beam splitter. The beam splitter is designed to power divide the incident radiation into reflected and transmitted components for interferometer measurement of spectral features in the mean cosmic radio background. Analysis of a 2-element interferometer configuration with a vertical beam splitter between a pair of antennas leads to the requirement that the beam splitter be a resistive s...

  7. Wideband FM Demodulation and Multirate Frequency Transformations

    Science.gov (United States)

    2016-12-15

    Noble identities to extend the proposed approach to larger wideband to narrowband conversion factors and more practical implementations. We further...framework . . . . . . . . . . . . . . . . . . . . . 8 2 Block diagrams of the alternative MFT system for large conversion factors (a) and the Noble Identity ...of both MFT frameworks with conversion factor R = 128 and normalized radian frequency shift wd = 0.1π under the extreme senario with modulation index

  8. Wideband DOA Estimation through Projection Matrix Interpolation

    OpenAIRE

    Selva, J.

    2017-01-01

    This paper presents a method to reduce the complexity of the deterministic maximum likelihood (DML) estimator in the wideband direction-of-arrival (WDOA) problem, which is based on interpolating the array projection matrix in the temporal frequency variable. It is shown that an accurate interpolator like Chebyshev's is able to produce DML cost functions comprising just a few narrowband-like summands. Actually, the number of such summands is far smaller (roughly by factor ten in the numerical ...

  9. Hey! A Scorpion Stung Me!

    Science.gov (United States)

    ... cool, damp places like basements, woodpiles, and junk piles. Usually, they're nocturnal (they sleep during the ... to spend time. Don't play in junk piles or woodpiles, and if you are working outside ...

  10. Extension of the ITU Channel Models for Wideband (OFDM) Systems

    DEFF Research Database (Denmark)

    Sørensen, Troels Bundgaard; Frederiksen, Frank

    2005-01-01

    for the evaluation of wideband system concepts with frequency dependent characteristics, e.g. frequency domain link adaptation and packet scheduling, both of which are likely to be part of future wideband systems such as based on OFDM. With the suggested procedure the frequency correlation can be kept approximately...

  11. Real-time wideband holographic surveillance system

    Science.gov (United States)

    Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.

    1996-09-17

    A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm. 28 figs.

  12. Compact super-wideband optical antenna

    Science.gov (United States)

    Wang, Wen C.; Forber, Richard; Bui, Kenneth

    2009-05-01

    We present progress on advanced optical antennas, which are compact, small size-weight-power units capable to receive super wideband radiated RF signals from 30 MHz to over 3 GHz. Based on electro-optical modulation of fiber-coupled guided wave light, these dielectric E-field sensors exhibit dipole-like azimuthal omni directionality, and combine small size (channels, and high EO sensing materials. The antenna system photonic link consists of a 1550 nm PM fiber-pigtailed laser, a specialized optical modulator antenna in channel waveguide format, a wideband photoreceiver, and optical phase stabilizing components. The optical modulator antenna design employs a dielectric (no electrode) Mach-Zehnder interferometer (MZI) arranged so that sensing RF bandwidth is not limited by optical transit time effects, and MZI phase drift is bias stabilized. For a prototype optical antenna system that is < 100 in3, < 10 W, < 5 lbs, we present test data on sensitivity (< 20 mV/m-Hz1/2), RF bandwidth, and antenna directionality, and show good agreement with theoretical predictions.

  13. Integrated wide-band low-background amplifiers

    International Nuclear Information System (INIS)

    Il'yushchenko, I.I.

    1980-01-01

    Ways of increasing stability and reproduction of characteristics of wide-band integral amplifiers that would to the least extent increase their background noises, are discussed. Considered are some certain flowsheets of integral wide-band amplifiers with low background noise of foreign production which differ from one another by construction of inlet cascades as well as by the applied feedback type. The principal flowsheets of the amplifiers and their main performances are presented. The analysis of the data obtained has revealed that microcircuits made of cascades with a common emitter and local combined feedback are most wide-band among all the considered microcircuits [ru

  14. Wideband Autonomous Cognitive Radios for Networked Satellites Communications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Wideband Autonomous Cognitive Radios (WACRs) are advanced radios that have the ability to sense state of the RF spectrum and the network and self-optimize its...

  15. Wideband QAMC reflector's antenna for low profile applications

    Science.gov (United States)

    Grelier, M.; Jousset, M.; Mallégol, S.; Lepage, A. C.; Begaud, X.; LeMener, J. M.

    2011-06-01

    A wideband reflector's antenna based on quasi-artificial magnetic conductor is proposed. To validate the design, an Archimedean spiral has been backed to this new reflector. In comparison to classical solution using absorbent material, the prototype presents a very low thickness of λ/15 at the lowest operating frequency and an improved gain over a 2.4:1 bandwidth. The whole methodology to design this reflector can be applied to other wideband antennas.

  16. An Ultra-Wideband Millimeter-Wave Phased Array

    Science.gov (United States)

    Novak, Markus H.; Miranda, Felix A.; Volakis, John L.

    2016-01-01

    Wideband millimeter-wave arrays are of increasing importance due to their growing use in high data rate systems, including 5G communication networks. In this paper, we present a new class of ultra-wideband millimeter wave arrays that operate from nearly 20 GHz to 90 GHz. The array is based on tightly coupled dipoles. Feeding designs and fabrication challenges are presented, and a method for suppressing feed resonances is provided.

  17. Multichannel Baseband Processor for Wideband CDMA

    Science.gov (United States)

    Jalloul, Louay M. A.; Lin, Jim

    2005-12-01

    The system architecture of the cellular base station modem engine (CBME) is described. The CBME is a single-chip multichannel transceiver capable of processing and demodulating signals from multiple users simultaneously. It is optimized to process different classes of code-division multiple-access (CDMA) signals. The paper will show that through key functional system partitioning, tightly coupled small digital signal processing cores, and time-sliced reuse architecture, CBME is able to achieve a high degree of algorithmic flexibility while maintaining efficiency. The paper will also highlight the implementation and verification aspects of the CBME chip design. In this paper, wideband CDMA is used as an example to demonstrate the architecture concept.

  18. Multichannel Baseband Processor for Wideband CDMA

    Directory of Open Access Journals (Sweden)

    Jim Lin

    2005-07-01

    Full Text Available The system architecture of the cellular base station modem engine (CBME is described. The CBME is a single-chip multichannel transceiver capable of processing and demodulating signals from multiple users simultaneously. It is optimized to process different classes of code-division multiple-access (CDMA signals. The paper will show that through key functional system partitioning, tightly coupled small digital signal processing cores, and time-sliced reuse architecture, CBME is able to achieve a high degree of algorithmic flexibility while maintaining efficiency. The paper will also highlight the implementation and verification aspects of the CBME chip design. In this paper, wideband CDMA is used as an example to demonstrate the architecture concept.

  19. Wideband pulse amplifiers for the NECTAr chip

    Science.gov (United States)

    Sanuy, A.; Delagnes, E.; Gascon, D.; Sieiro, X.; Bolmont, J.; Corona, P.; Feinstein, F.; Glicenstein, J.-F.; Naumann, C. L.; Nayman, P.; Ribó, M.; Tavernet, J.-P.; Toussenel, F.; Vincent, P.; Vorobiov, S.

    2012-12-01

    The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

  20. Wideband pulse amplifiers for the NECTAr chip

    International Nuclear Information System (INIS)

    Sanuy, A.; Delagnes, E.; Gascon, D.; Sieiro, X.; Bolmont, J.; Corona, P.; Feinstein, F.; Glicenstein, J-F.; Naumann, C.L.; Nayman, P.; Ribó, M.

    2012-01-01

    The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1–3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

  1. Wideband pulse amplifiers for the NECTAr chip

    Energy Technology Data Exchange (ETDEWEB)

    Sanuy, A., E-mail: asanuy@ecm.ub.es [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Delagnes, E. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Gascon, D. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Sieiro, X. [Departament d' Electronica, Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Bolmont, J.; Corona, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Feinstein, F. [LUPM, Universite Montpellier II and IN2P3/CNRS, CC072, bat. 13, place Eugene Bataillon, 34095 Montpellier (France); Glicenstein, J-F. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Naumann, C.L.; Nayman, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Ribo, M. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); and others

    2012-12-11

    The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

  2. Ultra-Wideband Transceivers for Cochlear Implants

    Directory of Open Access Journals (Sweden)

    Reisenzahn Alexander

    2005-01-01

    Full Text Available Ultra-wideband (UWB radio offers low power consumption, low power spectral density, high immunity against interference, and other benefits, not only for consumer electronics, but also for medical devices. A cochlear implant (CI is an electronic hearing apparatus, requiring a wireless link through human tissue. In this paper we propose an UWB link for a data rate of Mbps and a propagation distance up to 500 mm. Transmitters with step recovery diode and transistor pulse generators are proposed. Two types of antennas and their filter characteristics in the UWB spectrum will be discussed. An ultra-low-power back tunnel diode receiver prototype is described and compared with conventional detector receivers.

  3. Elementary wideband timing of radio pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Pennucci, Timothy T. [University of Virginia, Department of Astronomy, P.O. Box 400325 Charlottesville, VA 22904-4325 (United States); Demorest, Paul B.; Ransom, Scott M., E-mail: pennucci@virginia.edu, E-mail: pdemores@nrao.edu, E-mail: sransom@nrao.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States)

    2014-08-01

    We present an algorithm for the simultaneous measurement of a pulse time-of-arrival (TOA) and dispersion measure (DM) from folded wideband pulsar data. We extend the prescription from Taylor's 1992 work to accommodate a general two-dimensional template 'portrait', the alignment of which can be used to measure a pulse phase and DM. We show that there is a dedispersion reference frequency that removes the covariance between these two quantities and note that the recovered pulse profile scaling amplitudes can provide useful information. We experiment with pulse modeling by using a Gaussian-component scheme that allows for independent component evolution with frequency, a 'fiducial component', and the inclusion of scattering. We showcase the algorithm using our publicly available code on three years of wideband data from the bright millisecond pulsar J1824–2452A (M28A) from the Green Bank Telescope, and a suite of Monte Carlo analyses validates the algorithm. By using a simple model portrait of M28A, we obtain DM trends comparable to those measured by more standard methods, with improved TOA and DM precisions by factors of a few. Measurements from our algorithm will yield precisions at least as good as those from traditional techniques, but is prone to fewer systematic effects and is without ad hoc parameters. A broad application of this new method for dispersion measure tracking with modern large-bandwidth observing systems should improve the timing residuals for pulsar timing array experiments, such as the North American Nanohertz Observatory for Gravitational Waves.

  4. DOD Use of Commercial Wideband Satellite Communications Systems: How Much is Needed, and How Do We Get It?

    National Research Council Canada - National Science Library

    Hutchens, Robert

    2001-01-01

    ..., A key enabler to this end is sufficient wideband satellite communications connectivity DoD's organic wideband satellite communications capabilities are inadequate, so commercial services must be used...

  5. Apparatus And Method For Wireless Monitoring Using Ultra-wideband Frequencies

    KAUST Repository

    Sana, Furrukh

    2015-04-23

    A system for and a method of wirelessly monitoring one or more patients can include transmitting ultra-wideband pulses toward the one or more patients, receiving ultra-wideband signals, and sampling the ultra-wideband signals. Sampling the ultra-wideband pulses can be performed with a sample rate that is less than the Nyquist rate. Impulse response can be estimated and/or recovered by exploiting sparsity of the impulse response.

  6. A Channelization-Based DOA Estimation Method for Wideband Signals

    Directory of Open Access Journals (Sweden)

    Rui Guo

    2016-07-01

    Full Text Available In this paper, we propose a novel direction of arrival (DOA estimation method for wideband signals with sensor arrays. The proposed method splits the wideband array output into multiple frequency sub-channels and estimates the signal parameters using a digital channelization receiver. Based on the output sub-channels, a channelization-based incoherent signal subspace method (Channelization-ISM and a channelization-based test of orthogonality of projected subspaces method (Channelization-TOPS are proposed. Channelization-ISM applies narrowband signal subspace methods on each sub-channel independently. Then the arithmetic mean or geometric mean of the estimated DOAs from each sub-channel gives the final result. Channelization-TOPS measures the orthogonality between the signal and the noise subspaces of the output sub-channels to estimate DOAs. The proposed channelization-based method isolates signals in different bandwidths reasonably and improves the output SNR. It outperforms the conventional ISM and TOPS methods on estimation accuracy and dynamic range, especially in real environments. Besides, the parallel processing architecture makes it easy to implement on hardware. A wideband digital array radar (DAR using direct wideband radio frequency (RF digitization is presented. Experiments carried out in a microwave anechoic chamber with the wideband DAR are presented to demonstrate the performance. The results verify the effectiveness of the proposed method.

  7. Ultra wideband wireless body area networks

    CERN Document Server

    Thotahewa, Kasun Maduranga Silva; Yuce, Mehmet Rasit

    2014-01-01

    This book explores the design of ultra wideband (UWB) technology for wireless body-area networks (WBAN).  The authors describe a novel implementation of WBAN sensor nodes that use UWB for data transmission and narrow band for data reception, enabling low power sensor nodes, with high data rate capability.  The discussion also includes power efficient, medium access control (MAC) protocol design for UWB based WBAN applications and the authors present a MAC protocol in which a guaranteed delivery mechanism is utilized to transfer data with high priority.  Readers will also benefit from this book’s feasibility analysis of the UWB technology for human implant applications through the study of electromagnetic and thermal power absorption of human tissue that is exposed to UWB signals.   • Describes hardware platform development for IR-UWB based WBAN communication; • Discusses power efficient medium access control (MAC) protocol design for IR-UWB based WBAN applications; • Includes feasibility analy...

  8. Ultra-wideband ranging precision and accuracy

    International Nuclear Information System (INIS)

    MacGougan, Glenn; O'Keefe, Kyle; Klukas, Richard

    2009-01-01

    This paper provides an overview of ultra-wideband (UWB) in the context of ranging applications and assesses the precision and accuracy of UWB ranging from both a theoretical perspective and a practical perspective using real data. The paper begins with a brief history of UWB technology and the most current definition of what constitutes an UWB signal. The potential precision of UWB ranging is assessed using Cramer–Rao lower bound analysis. UWB ranging methods are described and potential error sources are discussed. Two types of commercially available UWB ranging radios are introduced which are used in testing. Actual ranging accuracy is assessed from line-of-sight testing under benign signal conditions by comparison to high-accuracy electronic distance measurements and to ranges derived from GPS real-time kinematic positioning. Range measurements obtained in outdoor testing with line-of-sight obstructions and strong reflection sources are compared to ranges derived from classically surveyed positions. The paper concludes with a discussion of the potential applications for UWB ranging

  9. Wide-band cable systems at SLAC

    International Nuclear Information System (INIS)

    Struven, W.

    1983-01-01

    SLAC's first cable TV system was installed in 1979 to remotely monitor a narrow pulse which was generated in the west end of the klystron gallery. When Stanford Linear Collider (SLC) experimental work started at the west end of the accelerator, the original 1979 cable was upgraded to a bidirectional system so that 2 MBaud point-to-point data and several video and 9600 baud channels could be transmitted. The implementation of the SLC requires a complete upgrading of the accelerator control system. The system is based on a distributed processing configuration using a PDP11/780 VAX in the Main Control Center (MCC) and Intel single-board computers in a multibus configuration along the accelerator. The high-speed data linking is supplied by a 1 MBaud Time Division Multiple Access (TDMA) Network. The same cable is used to provide video, low-speed data, voice and high-speed point-to-point data services. The transmission system will utilize a wideband midsplit cable facility to collect and distribute signals to all parts of the network

  10. An Analog Correlator for Ultra-Wideband Receivers

    Directory of Open Access Journals (Sweden)

    Tu Chunjiang

    2005-01-01

    Full Text Available We present a new analog circuit exhibiting high bandwidth and low distortion, specially designed for signal correlation in an ultra-wideband receiver front end. The ultra-wideband short impulse signals are correlated with a local pulse template by the correlator. A comparator then samples the output for signal detection. A typical Gilbert mixer core is adopted for multiplication of broadband signals up to . As a result of synchronization of the received signal and the local template, the output voltage level after integration and sampling can reach up to , which is sufficient for detection by the comparator. The circuit dissipates about from double voltage supplies of and using SiGe BiCMOS technology. Simulation results are presented to show the feasibility of this circuit design for use in ultra-wideband receivers.

  11. Effect of direction on loudness for wideband and reverberant sounds

    DEFF Research Database (Denmark)

    Sivonen, Ville Pekka; Ellermeier, Wolfgang

    2006-01-01

    The effect of incidence angle on loudness was investigated for wideband and reverberant sounds. In an adaptive procedure, five listeners matched the loudness of a sound coming from five incidence angles in the horizontal plane to that of the same sound with frontal incidence. The stimuli were...... presented to the listeners via individual binaural synthesis. The results confirm that loudness depends on sound incidence angle, as it does for narrow-band, anechoic sounds. The directional effects, however, were attenuated with the wideband and reverberant stimuli used in the present investigation....

  12. Ultra-wideband RCS reduction using novel configured chessboard metasurface

    International Nuclear Information System (INIS)

    Zhuang Ya-Qiang; Wang Guang-Ming; Xu He-Xiu

    2017-01-01

    A novel artificial magnetic conductor (AMC) metasurface is proposed with ultra-wideband 180° phase difference for radar cross section (RCS) reduction. It is composed of two dual-resonant AMC cells, which enable a broadband phase difference of 180°±30° from 7.9 GHz to 19.2 GHz to be achieved. A novel strategy is devised by dividing each rectangular grid in a chessboard configuration into four triangular grids, leading to a further reduction of peak bistatic RCS. Both full-wave simulation and measurement results show that the proposed metasurface presents a good RCS reduction property over an ultra-wideband frequency range. (paper)

  13. Timed arrays wideband and time varying antenna arrays

    CERN Document Server

    Haupt, Randy L

    2015-01-01

    Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

  14. Substrate Effects in Wideband SiGe HBT Mixer Circuits

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Vidkjær, Jens; Krozer, Viktor

    2005-01-01

    are also applied to predict short distance substrate coupling effects. Simulation results using extracted equivalent circuit models and substrate coupling networks are compared with experimental results obtained on a wideband mixer circuit implemented in a 0.35 μm, 60 GHz ft SiGe HBT BiCMOS process.......In this paper, the influence from substrate effects on the performance of wideband SiGe HBT mixer circuits is investigated. Equivalent circuit models including substrate networks are extracted from on-wafer test structures and compared with electromagnetic simulations. Electromagnetic simulations...

  15. A new metamaterial-based wideband rectangular invisibility cloak

    Science.gov (United States)

    Islam, S. S.; Hasan, M. M.; Faruque, M. R. I.

    2018-02-01

    A new metamaterial-based wideband electromagnetic rectangular cloak is being introduced in this study. The metamaterial unit cell shows sharp transmittances in the C- and X-bands and displays wideband negative effective permittivity region there. The metamaterial unit cell was then applied in designing a rectangular-shaped electromagnetic cloak. The scattering reduction technique was adopted for the cloaking operation. The cloak operates in the certain portion of C-and X-bands that covers more than 4 GHz bandwidth region. The experimental results were provided as well for the metamaterial and the cloak.

  16. Wideband filter radiometers for blackbody temperature measurements

    Science.gov (United States)

    Boivin, L. P.; Bamber, C.; Gaertner, A. A.; Gerson, R. K.; Woods, D. J.; Woolliams, E. R.

    2010-10-01

    The use of high-temperature blackbody (HTBB) radiators to realize primary spectral irradiance scales requires that the operating temperature of the HTBB be accurately determined. We have developed five filter radiometers (FRs) to measure the temperature of the National Research Council of Canada's HTBB. The FRs are designed to minimize sensitivity to ambient temperature fluctuations. They incorporate air-spaced colored glass filters and a Si photodiode detector that are housed in a cell whose temperature is controlled to ±0.1°C by means of annular thermoelectric elements at the front and rear of the cell. These wideband filter radiometers operate in four different wavelength bands. The spectral responsivity measurements were performed in an underfill geometry for a power-mode calibration that is traceable to NRC's cryogenic radiometer. The spectral temperature sensitivity of each of these FRs has been measured. The apertures for these FRs were cold-formed by swaging machine-cut apertures onto precision dowel pins. A description of the filter radiometer design, fabrication and testing, together with a detailed uncertainty analysis, is presented. We derive the equations that relate the spectral irradiance measured by the FRs to the spectral radiance and temperature of the HTBB, and deal specifically with the change of index of refraction over the path of the radiation from the interior of the HTBB to the FRs. We believe these equations are more accurate than recently published derivations. Our measurements of the operating temperature of our HTBB working at temperatures near 2500 K, 2700 K and 2900 K, together with measurements using a pyrometer, show agreement between the five filter radiometers and with the pyrometer to within the estimated uncertainties.

  17. Optical networks for wideband sensor array

    Science.gov (United States)

    Sheng, Lin Horng

    2011-12-01

    This thesis presents the realization of novel systems for optical sensing networks with an array of long-period grating (LPG) sensors. As a launching point of the thesis, the motivation to implement optical sensing network in precisely catering LPG sensors is presented. It highlights the flexibility of the sensing network to act as the foundation in order to boost the application of the various LPG sensor design in biological and chemical sensing. After the thorough study on the various optical sensing networks, sub-carrier multiplexing (SCM) and optical time division multiplexing (OTDM) schemes are adopted in conjunction with tunable laser source (TLS) to facilitate simultaneous interrogation of the LPG sensors array. In fact, these systems are distinct to have the capability to accommodate wideband optical sensors. Specifically, the LPG sensors which is in 20nm bandwidth are identified to operate in these systems. The working principles of the systems are comprehensively elucidated in this thesis. It highlights the mathematical approach to quantify the experimental setup of the optical sensing network. Additionally, the system components of the designs are identified and methodically characterized so that the components well operate in the designed environment. A mockup has been setup to demonstrate the application in sensing of various liquid indices and analyse the response of the LPG sensors in order to evaluate the performance of the systems. Eventually, the resemblance of the demultiplexed spectral response to the pristine spectral response are quantified to have excellent agreement. Finally, the promising result consistency of the systems is verified through repeatability test.

  18. Naloxone treatment alters gene expression in the mesolimbic reward system in 'junk food' exposed offspring in a sex-specific manner but does not affect food preferences in adulthood.

    Science.gov (United States)

    Gugusheff, J R; Ong, Z Y; Muhlhausler, B S

    2014-06-22

    We have previously reported that the opioid receptor blocker, naloxone, is less effective in reducing palatable food intake in offspring exposed to a maternal cafeteria diet during the perinatal period, implicating a desensitization of the central opioid pathway in the programming of food preferences. The present study aimed to investigate the effect of a maternal cafeteria diet and naloxone treatment on the development of the mesolimbic reward pathway and food choices in adulthood. We measured mRNA expression of key components of the reward pathway (mu-opioid receptor, proenkephalin, tyrosine hydroxylase, D1 and D2 receptors and the dopamine active transporter (DAT)) in the nucleus accumbens (NAc) and ventral tegmental area (VTA) of the offspring of control and cafeteria fed (JF) dams at weaning and after a 10-day naloxone treatment post-weaning and determined food preferences in adulthood in the remaining offspring. Naloxone treatment decreased the expression of DAT by 8.2 fold in female control offspring but increased it by 4.3 fold in female offspring of JF dams relative to the saline-injected reference groups. Proenkephalin mRNA expression was higher in the NAc of female JF offspring compared to controls, independent of naloxone treatment (Pfood preferences in adulthood in either control or JF offspring. These data indicate that prenatal exposure to a cafeteria diet alters the impact of opioid signaling blockade in the early post-weaning period on gene expression in the central reward pathway in a sex specific manner, but that these changes in gene expression do not appear to have any persistent impact on food preferences in adulthood. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. [Weak evidence concerning sedentary lifestyle and its association with cardio-metabolic illness among young people. "Junk food" and late evenings in front of the screen part of a complex connection].

    Science.gov (United States)

    Fröberg, Andreas; Raustorp, Anders

    2015-06-16

    During recent decades there has been a rapidly growing interest in youths' sedentary behaviour and its association with cardio-metabolic health. Currently there is little-to-no evidence for a cross-sectional and longitudinal association between volume and pattern (bouts and breaks) of objectively measured sedentary behavior and body weight in youth. Likewise, there is little-to-no evidence for a cross-sectional association between volume and pattern of objectively measured sedentary behavior and other markers for cardio-metabolic risk in youth. However, there is sufficient evidence for a cross-sectional and longitudinal association between screen-time and body weight and blood pressure and blood lipids. Furthermore, there is evidence for a cross-sectional association between youths' screen-time and clustered metabolic risk and insulin resistance. Overall, the level of evidence was low and, therefore, caution is required when interpreting the results.

  20. Ultra wideband coplanar waveguide fed spiral antenna for humanitarian demining

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne; Appel-Hansen, Jørgen

    2000-01-01

    to 1 bandwidth with a return loss better than 10 dB from 0.4 to 3.8 GHz is presented. A wideband balun covering the frequency range of the antenna was developed. The constructed spiral antenna is very useful in a stepped frequency ground penetrating radar for humanitarian demining due to the very...

  1. Ultra-wideband MMICs for remote sensing applications

    DEFF Research Database (Denmark)

    Johansen, Tom Keinicke; Vidkjær, Jens; Krozer, Viktor

    2003-01-01

    This paper presents an overview of the current activity at the Technical University of Denmark in the field of ultra-wideband monolitic microwave integrated circuits (MMICs) for next-generation high-resolution synthetic aperature radar (SAR) systems. The transfer function requirements for MMIC co...

  2. Resilience of LTE networks against smart jamming attacks: Wideband model

    KAUST Repository

    Aziz, Farhan M.; Shamma, Jeff S.; Stuber, Gordon L.

    2015-01-01

    communications. We have previously shown that LTE networks are vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart jammers. In this paper, we extend our previous work on resilience of LTE networks to wideband multipath fading channel

  3. Digital Receiver Design for Transmitted Reference Ultra-Wideband Systems

    NARCIS (Netherlands)

    Wang, Y.; Leus, G.; Van der Veen, A.J.

    2009-01-01

    A complete detection, channel estimation, synchronization, and equalization scheme for a transmitted reference (TR) ultra-wideband (UWB) system is proposed in this paper. The scheme is based on a data model which admits a moderate data rate and takes both the interframe interference (IFI) and the

  4. Aliasing-free wideband beamforming using sparse signal representation

    NARCIS (Netherlands)

    Tang, Z.; Blacquière, G.; Leus, G.

    2011-01-01

    Sparse signal representation (SSR) is considered to be an appealing alternative to classical beamforming for direction-of-arrival (DOA) estimation. For wideband signals, the SSR-based approach constructs steering matrices, referred to as dictionaries in this paper, corresponding to different

  5. Thermal Studies on the SPS Wideband Transverse Feedback Kicker

    CERN Document Server

    Roggen, Toon; Hofle, Wolfgang; Montesinos, Eric; CERN. Geneva. ATS Department

    2016-01-01

    As part of the SPS wideband transverse feedback system in the framework of the LHC Injector Upgrade (LIU) project, a wideband kicker design is being proposed. Vertical beam instabilities due to intensity dependent effects (electron cloud instability (ECI) and transverse mode coupling instability (TMCI)) are potentially suppressed by using a feedback system driving such a kicker system. One of the options for a kicker is a one meter long slotted-coaxial kicker, providing a substantial vertical kick strength (10ˉ5 –10ˉ4 eV.s/m) over a bandwidth ranging from nearly DC to 1 GHz. The necessary kick strength requires a total power of 4 kW. This note describes thermal studies that assisted in the material choice of the feedthroughs of the slotted-coaxial kicker and guided the design choices.

  6. Wideband MIMO Channel Capacity Analysis in Multiprobe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Kyosti, Pekka; Nielsen, Jesper Ødum

    2016-01-01

    been used to determine the test area size for a limited number of probes. However, it is desirable that the test area size is defined in terms of data rate deviation of the simulated channel in the laboratory from that of the target channel model. This paper reports MIMO capacity analysis results...... for wideband spatio-temporal channel models, with emphasis on the impact of spatial correlation at the transmit (Tx) side, the channel model, and the spatial correlation at the Rx side on the capacity simulation accuracy. Simulation results show that the number of probes is irrelevant to capacity simulation......This paper discusses over the air (OTA) testing for multiple input multiple output (MIMO) capable terminals with emphasis on wideband MIMO channel capacity analysis in a multi-probe anechoic chamber setup. In the literature, the spatial correlation simulation accuracy at the receiver (Rx) side has...

  7. Closely Mounted Compact Wideband Diversity Antenna for Mobile Phone Applications

    Directory of Open Access Journals (Sweden)

    Bunggil Yu

    2012-01-01

    Full Text Available Here a compact wideband diversity antenna covering the PCS/UMTS/WiMAX bands with high isolation and low enveloped correlation coefficient (ECC is proposed. To widen the bandwidth, the proposed antenna uses a structure with a gap-coupled feed and an inductively shorted line that has capacitive compensation between the radiator and the ground plane. Also, a suspended line with a parasitic element is used to enhance the isolation between the two antennas.

  8. Doppler Processing with Ultra-Wideband (UWB) Radar Revisited

    Science.gov (United States)

    2018-01-01

    REPORT TYPE Technical Note 3. DATES COVERED (From - To) December 2017 4. TITLE AND SUBTITLE Doppler Processing with Ultra-Wideband (UWB) Radar...unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT This technical note revisits previous work performed at the US Army Research Laboratory related to...target considered previously is proportional to a delayed version of the transmitted signal, up to a complex constant factor. We write the received

  9. A wideband Noise-Canceling CMOS LNA exploiting a transformer

    NARCIS (Netherlands)

    Blaakmeer, S.C.; Klumperink, Eric A.M.; Leenaerts, Domine M.W.; Nauta, Bram

    2006-01-01

    Abstract — A broadband LNA incorporating single-ended to differential conversion, has been successfully implemented using a noise-canceling technique and a single on-chip transformer. The LNA achieves a high voltage gain of 19dB, a wideband input match (2.5–4.0 GHz), and a Noise Figure of 4–5.4 dB,

  10. A wideband Noise-Canceling CMOS LNA exploiting a transformer

    NARCIS (Netherlands)

    Blaakmeer, S.C.; Klumperink, Eric A.M.; Leenaerts, Domine M.W.; Nauta, Bram

    2006-01-01

    A broadband LNA incorporating single-ended to differential conversion, has been successfully implemented using a noise-canceling technique and a single on-chip transformer. The LNA achieves a high voltage gain of 19dB, a wideband input match (2.5–4.0 GHz), and a Noise Figure of 4–5.4 dB, while

  11. An inductorless wideband LNA with a new noise canceling technique

    OpenAIRE

    MOGHADAM, POURIA PAZHOUHESH; ABRISHAMIFAR, ADIB

    2017-01-01

    An inductorless wideband low-noise amplifier (LNA) employing a new noise canceling technique for multistandard applications is presented. The main amplifier has a cascode common gate structure, which provides good input impedance matching and isolation. The proposed noise canceling technique not only improves the noise figure and power gain but also embeds a g$_{m}$-boosting technique in itself, which reduces the power consumption of the main amplifier. Using current-steering and ...

  12. Ultra-Wideband Electromagnetic Pulse Propagation through Causal Media

    Science.gov (United States)

    2016-03-04

    AFRL-AFOSR-VA-TR-2016-0112 Ultra-Wideband Electromagnetic Pulse Propagation through Causal Media Natalie Cartwright RESEARCH FOUNDATION OF STATE... Electromagnetic Pulse Propagation through Causal Media 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-13-1-0013 5c.  PROGRAM ELEMENT NUMBER 61102F 6...SUPPLEMENTARY NOTES 14. ABSTRACT When an electromagnetic pulse travels through a dispersive material each frequency of the transmitted pulse changes in both

  13. Ruggedizing Printed Circuit Boards Using a Wideband Dynamic Absorber

    Directory of Open Access Journals (Sweden)

    V.C. Ho

    2003-01-01

    Full Text Available The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB for use in hostile industrial and military environment are either insufficient or expensive. This paper addresses a novel approach towards ruggedizing commercial-off-the-shelf PCBs using a miniature wideband dynamic absorber. The optimisation technique used relies on the experimentally measured vibration spectra and complex receptance of the original PCB.

  14. Ultra-Wideband Coplanar-Fed Monopoles: A Comparative Study

    Directory of Open Access Journals (Sweden)

    J. Jilkova

    2008-04-01

    Full Text Available The paper provides an experimental comparison of four types of ultra-wideband coplanar-fed planar monopole antennas. Parameters of the open stub completed by an L-shaped monopole and the cross monopole were adopted from the literature. The forked monopole and the coplanar monopole were fabricated and measured. Monopoles were compared from the viewpoint of the impedance bandwidth, gain, directivity patterns and dimensions.

  15. A Wideband Autonomous Cognitive Radio Development and Prototyping System

    Science.gov (United States)

    2017-11-14

    three infrastructure modules (a Network Spectrum Analyzer, a Vector Signal Generator and a Rapid Printed Circuit Board (PCB) Fabrication Unit) and a...Antennas for Mobile Platforms”, 02/01/17-12/31/17 ($100K), Honeywell FM&T. 3. S. K. Jayaweera (Principal Investigator) and C. G. Christodoulou “Wideband...Signal Generator and a Rapid Printed Circuit Board (PCB) Fabrication Unit) and a Software Defined Radio (SDR) testbed made of several USRP SDR

  16. Detection of moving humans in UHF wideband SAR

    Science.gov (United States)

    Sjögren, Thomas K.; Ulander, Lars M. H.; Frölind, Per-Olov; Gustavsson, Anders; Stenström, Gunnar; Jonsson, Tommy

    2014-06-01

    In this paper, experimental results for UHF wideband SAR imaging of humans on an open field and inside a forest is presented. The results show ability to detect the humans and suggest possible ways to improve the results. In the experiment, single channel wideband SAR mode of the UHF UWB system LORA developed by Swedish Defence Research Agency (FOI). The wideband SAR mode used in the experiment was from 220 to 450 MHz, thus with a fractional bandwidth of 0.68. Three humans walking and one stationary were available in the scene with one of the walking humans in the forest. The signature of the human in the forest appeared on the field, due to azimuth shift from the positive range speed component. One human on the field and the one in the forest had approximately the same speed and walking direction. The signatures in the SAR image were compared as a function of integration time based on focusing using the average relative speed of these given by GPS logs. A signal processing gain was obtained for the human in forest until approximately 15 s and 35 s for the human on the field. This difference is likely explained by uneven terrain and trees in the way, causing a non-straight walking path.

  17. Wideband aural acoustic absorbance predicts conductive hearing loss in children.

    Science.gov (United States)

    Keefe, Douglas H; Sanford, Chris A; Ellison, John C; Fitzpatrick, Denis F; Gorga, Michael P

    2012-12-01

    This study tested the hypothesis that wideband aural absorbance predicts conductive hearing loss (CHL) in children medically classified as having otitis media with effusion. Absorbance was measured in the ear canal over frequencies from 0.25 to 8 kHz at ambient pressure or as a swept tympanogram. CHL was defined using criterion air-bone gaps of 20, 25, and 30 dB at octaves from 0.25 to 4 kHz. A likelihood-ratio predictor of CHL was constructed across frequency for ambient absorbance, and across frequency and pressure for absorbance tympanometry. Performance was evaluated at individual frequencies and for any frequency at which a CHL was present. Absorbance and conventional 0.226-kHz tympanograms were measured in children of age three to eight years with CHL and with normal hearing. Absorbance was smaller at frequencies above 0.7 kHz in the CHL group than the control group. Based on the area under the receiver operating characteristic curve, wideband absorbance in ambient and tympanometric tests were significantly better predictors of CHL than tympanometric width, the best 0.226-kHz predictor. Accuracies of ambient and tympanometric wideband absorbance did not differ. Absorbance accurately predicted CHL in children and was more accurate than conventional 0.226-kHz tympanometry.

  18. Age effects in the human middle ear: Wideband acoustical measures

    Science.gov (United States)

    Feeney, M. Patrick; Sanford, Chris A.

    2004-12-01

    Studies that have examined age effects in the human middle ear using either admittance measures at 220 or 660 Hz or multifrequency tympanometry from 200 to 2000 Hz have had conflicting results. Several studies have suggested an increase in admittance with age, while several others have suggested a decrease in admittance with age. A third group of studies found no significant age effect. This study examined 226 Hz tympanometry and wideband energy reflectance and impedance at ambient pressure in a group of 40 young adults and a group of 30 adults with age >=60 years. The groups did not differ in admittance measures of the middle ear at 226 Hz. However, significant age effects were found in wideband energy reflectance and impedance. In particular, in older adults there was a comparative decrease in reflectance from 800 to 2000 Hz but an increase near 4000 Hz. The results suggest a decrease in middle-ear stiffness with age. The findings of this study hold relevance for understanding the aging process in the auditory system, for the establishment of normative data for wideband energy reflectance, for the possibility of a conductive component to presbycusis, and for the interpretation of otoacoustic emission measurements. .

  19. Ultra-Wideband Transceiver Design and Optimization

    Science.gov (United States)

    Mehra, Ashutosh

    The technology landscape has quickly changed over the last few years. Developments in personal area networks, IC technology, DSP processing and bio-medical devices have enabled the integration of short range communication into low cost personal health care solutions. Newer technologies and solutions are being developed to cater to the personal operating space(POS) and body area networks(BAN). Health care is driving towards using multiple sensor and therapeutic nodes inside the POS. Technology has enabled remote patient care where the patient has low cost on-body wearables that allow the patient/physician to access vital signs without the patient physically visiting the clinic. Big semiconductor giants want to move into the wearable health monitor space. Along with the developments in fitness based health wearables, there has been a lot of interest towards developing BAN devices catering to the 'mission-critical' wearables and implants. Hearing aids, EKG monitors, neurostimulators are some examples. This work explores the use of the 802.15 ulta wideband (UWB) standard for designing a radio to operate in the a wireless sensor network in the BAN. The specific application targeted is a hearing aid. However, the design in this work is capable of working in a low power low range application with the ability to have multiple data rates ranging from a few kHz to 10's of MHz. The first radio designed by Marconi using spark-gap transmitters was an impulse radio (IR). The IR UWB technology boasts of low power, low cost, high data rates, multiple channels, simultaneous networking, the ability to carry information through obstacles that more limited bandwidths cannot, and also potentially lower complexity hardware design. The inherent timing accuracy associated with the technology gives UWB transmissions immunity to multipath fading and are hence make them more suitable for a cluttered indoor environment. The key difference with the traditional narrowband transceiver is that

  20. 47 CFR 15.250 - Operation of wideband systems within the band 5925-7250 MHz.

    Science.gov (United States)

    2010-10-01

    ... of wideband systems within the band 5925-7250 MHz. (a) The −10 dB bandwidth of a device operating... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation of wideband systems within the band... variations in temperature and supply voltage. (b) The −10 dB bandwidth of the fundamental emission shall be...

  1. GaAs Wideband Low Noise Amplifier Design for Breast Cancer Detection System

    DEFF Research Database (Denmark)

    Yan, Lei; Krozer, Viktor; Delcourt, Sebastien

    2009-01-01

    Modern wideband systems require low-noise receivers with bandwidth approaching 10 GHz. This paper presents ultra-wideband stable low-noise amplifier MMIC with cascode and source follower buffer configuration using GaAs technology. Source degeneration, gate and shunt peaking inductors are used...

  2. Wideband Acoustic Immittance: Normative Study and Test-Retest Reliability of Tympanometric Measurements in Adults

    Science.gov (United States)

    Sun, Xiao-Ming

    2016-01-01

    Purpose: The purpose of this study was to present normative data of tympanometric measurements of wideband acoustic immittance and to characterize wideband tympanograms. Method: Data were collected in 84 young adults with strictly defined normal hearing and middle ear status. Energy absorbance (EA) was measured using clicks for 1/12-octave…

  3. Mutual Coupling Reduction for UWB MIMO Antennas with a Wideband Neutralization Line

    DEFF Research Database (Denmark)

    Zhang, Shuai; Pedersen, Gert F.

    2016-01-01

    A wideband neutralization line is proposed to reduce the mutual coupling of a compact ultrawideband (UWB) MIMO antenna. With the introduced decoupling method, the designed UWB MIMO antenna covers the band of 3.1-5 GHz with an isolation of higher than 22 dB. The proposed wideband neutralization line...

  4. 77 FR 1727 - Agency Information Collection Activities: Proposed Collection; Comments Requested; Extension of...

    Science.gov (United States)

    2012-01-11

    ... of appropriate automated, electronic, mechanical, or other technological collection techniques or... respondents associated with this information collection. Approximately 10.5 million cars become junk or are...

  5. Ultra-wideband WDM VCSEL arrays by lateral heterogeneous integration

    Science.gov (United States)

    Geske, Jon

    Advancements in heterogeneous integration are a driving factor in the development of evermore sophisticated and functional electronic and photonic devices. Such advancements will merge the optical and electronic capabilities of different material systems onto a common integrated device platform. This thesis presents a new lateral heterogeneous integration technology called nonplanar wafer bonding. The technique is capable of integrating multiple dissimilar semiconductor device structures on the surface of a substrate in a single wafer bond step, leaving different integrated device structures adjacent to each other on the wafer surface. Material characterization and numerical simulations confirm that the material quality is not compromised during the process. Nonplanar wafer bonding is used to fabricate ultra-wideband wavelength division multiplexed (WDM) vertical-cavity surface-emitting laser (VCSEL) arrays. The optically-pumped VCSEL arrays span 140 nm from 1470 to 1610 nm, a record wavelength span for devices operating in this wavelength range. The array uses eight wavelength channels to span the 140 nm with all channels separated by precisely 20 nm. All channels in the array operate single mode to at least 65°C with output power uniformity of +/- 1 dB. The ultra-wideband WDM VCSEL arrays are a significant first step toward the development of a single-chip source for optical networks based on coarse WDM (CWDM), a low-cost alternative to traditional dense WDM. The CWDM VCSEL arrays make use of fully-oxidized distributed Bragg reflectors (DBRs) to provide the wideband reflectivity required for optical feedback and lasing across 140 rim. In addition, a novel optically-pumped active region design is presented. It is demonstrated, with an analytical model and experimental results, that the new active-region design significantly improves the carrier uniformity in the quantum wells and results in a 50% lasing threshold reduction and a 20°C improvement in the peak

  6. Monostatic ultra-wideband GPR antenna for through wall detection

    Directory of Open Access Journals (Sweden)

    Ali Jawad

    2017-01-01

    Full Text Available The aim of this paper is to present a monostatic arc-shaped ultra-wideband (UWB printed monopole antenna system with 3-16 GHz frequency bandwidth suitable for through-wall detection. Ground penetrating radar (GPR technique is used for detection with the gain of 6.2 dB achieved for the proposed antenna using defected ground structure (DGS method. To serve the purpose, a simulation experiment of through-wall detection model is constructed which consists of a monostatic antenna act as transmitter and receiver, concrete wall and human skin model. The time domain reflection of obtained result is then analysed for target detection.

  7. Wide-band slow-wave systems simulation and applications

    CERN Document Server

    Staras, Stanislovas

    2012-01-01

    The field of electromagnetics has seen considerable advances in recent years, based on the wide applications of numerical methods for investigating electromagnetic fields, microwaves, and other devices. Wide-Band Slow-Wave Systems: Simulation and Applications presents new technical solutions and research results for the analysis, synthesis, and design of slow-wave structures for modern electronic devices with super-wide pass-bands. It makes available, for the first time in English, significant research from the past 20 years that was previously published only in Russian and Lithuanian. The aut

  8. Optically addressed ultra-wideband phased antenna array

    Science.gov (United States)

    Bai, Jian

    Demands for high data rate and multifunctional apertures from both civilian and military users have motivated development of ultra-wideband (UWB) electrically steered phased arrays. Meanwhile, the need for large contiguous frequency is pushing operation of radio systems into the millimeter-wave (mm-wave) range. Therefore, modern radio systems require UWB performance from VHF to mm-wave. However, traditional electronic systems suffer many challenges that make achieving these requirements difficult. Several examples includes: voltage controlled oscillators (VCO) cannot provide a tunable range of several octaves, distribution of wideband local oscillator signals undergo high loss and dispersion through RF transmission lines, and antennas have very limited bandwidth or bulky sizes. Recently, RF photonics technology has drawn considerable attention because of its advantages over traditional systems, with the capability of offering extreme power efficiency, information capacity, frequency agility, and spatial beam diversity. A hybrid RF photonic communication system utilizing optical links and an RF transducer at the antenna potentially provides ultra-wideband data transmission, i.e., over 100 GHz. A successful implementation of such an optically addressed phased array requires addressing several key challenges. Photonic generation of an RF source with over a seven-octave bandwidth has been demonstrated in the last few years. However, one challenge which still remains is how to convey phased optical signals to downconversion modules and antennas. Therefore, a feed network with phase sweeping capability and low excessive phase noise needs to be developed. Another key challenge is to develop an ultra-wideband array antenna. Modern frontends require antennas to be compact, planar, and low-profile in addition to possessing broad bandwidth, conforming to stringent space, weight, cost, and power constraints. To address these issues, I will study broadband and miniaturization

  9. Ultra-wideband and 60 GHz communications for biomedical applications

    CERN Document Server

    Yuce, Mehmet R

    2013-01-01

    This book investigates the design of devices, systems, and circuits for medical applications using the two recently established frequency bands: ultra-wideband (3.1-10.6 GHz) and 60 GHz ISM band. These two bands provide the largest bandwidths available for communication technologies and present many attractive opportunities for medical applications. The applications of these bands in healthcare are wireless body area network (WBAN), medical imaging, biomedical sensing, wearable and implantable devices, fast medical device connectivity, video data transmission, and vital signs monitoring. The r

  10. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    Science.gov (United States)

    Wu, Jia-Liang; Lin, Bao-Qin; Da, Xin-Yu

    2016-08-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x- or y-polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471387, 61271250, and 61571460).

  11. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    International Nuclear Information System (INIS)

    Wu Jia-Liang; Lin Bao-Qin; Da Xin-Yu

    2016-01-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x - or y -polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. (paper)

  12. Wide-band analog frequency modulation of optic signals using indirect techniques

    Science.gov (United States)

    Fitzmartin, D. J.; Balboni, E. J.; Gels, R. G.

    1991-01-01

    The wideband frequency modulation (FM) of an optical carrier by a radio frequency (RF) or microwave signal can be accomplished independent of laser type when indirect modulation is employed. Indirect modulators exploit the integral relation of phase to frequency so that phase modulators can be used to impress frequency modulation on an optical carrier. The use of integrated optics phase modulators, which are highly linear, enables the generation of optical wideband FM signals with very low intermodulation distortion. This modulator can be used as part of an optical wideband FM link for RF and microwave signals. Experimental results from the test of an indirect frequency modulator for an optical carrier are discussed.

  13. Realization of Miniaturized Multi-/Wideband Microwave Front-Ends

    Science.gov (United States)

    Al Shamaileh, Khair A.

    The ever-growing demand toward designing microwave front-end components with enhanced access to the radio spectrum (e.g., multi-/wideband functionality) and improved physical features (e.g., miniaturized circuitry, ease and cost of fabrication) is becoming more paramount than ever before. This dissertation proposes new design methodologies, simulations, and experimental validations of passive front-ends (i.e., antennas, couplers, dividers) at microwave frequencies. The presented design concepts optimize both electrical and physical characteristics without degrading the intended performance. The developed designs are essential to the upcoming wireless technologies. The first proposed component is a compact ultra-wideband (UWB) Wilkinson power divider (WPD). The design procedure is accomplished by replacing the uniform transmission lines in each arm of the conventional single-frequency divider with impedance-varying profiles governed by a truncated Fourier series. While such non-uniform transmission lines (NTLs) are obtained through the even-mode analysis, three isolation resistors are optimized in the odd-mode circuit to achieve proper isolation and output ports matching over the frequency range of interest. The proposed design methodology is systematic, and results in single-layered and compact structures. For verification purposes, an equal split WPD is designed, simulated, and measured. The obtained results show that the input and output ports matching as well as the isolation between the output ports are below --10 dB; whereas the transmission parameters vary between --3.2 dB and --5 dB across the 3.1--10.6 GHz band. The designed divider is expected to find applications in UWB antenna diversity, multiple-input-multiple-output (MIMO) schemes, and antenna arrays feeding networks. The second proposed component is a wideband multi-way Bagley power divider (BPD). Wideband functionality is achieved by replacing the single-frequency matching uniform microstrip lines in

  14. [Auditory training with wide-band white noise: effects on the recruitment (III)].

    Science.gov (United States)

    Domínguez Ugidos, L J; Rodríguez Morejón, C; Vallés Varela, H; Iparraguirre Bolinaga, V; Knaster del Olmo, J

    2001-05-01

    The auditory training with wide-band white noise is a methodology for the qualitative recovery of the hearing loss in people suffering from sensorineural hearing loss. It is based on the application of a wide-band white modified noise. In a prospective study, we have assessed the modifications of the recruitment coefficient in a sample of 48 patients who have followed a program of 15 auditory training with wide-band white noise sessions. The average improvement of the recruitment coefficient expressed in percentage is a 7.7498%, which comes up to 23.5249% in the case of a binaural recruitment coefficient. From our results, it can be deduced that the auditory training with wide-band white noise reduces the recruitment. That is to say, the decrease of the recruitment in high intensities both binaurally and in all ears.

  15. Fast optimization method of designing a wideband metasurface without using the Pancharatnam-Berry phase.

    Science.gov (United States)

    Sui, Sai; Ma, Hua; Lv, Yueguang; Wang, Jiafu; Li, Zhiqiang; Zhang, Jieqiu; Xu, Zhuo; Qu, Shaobo

    2018-01-22

    Arbitrary control of electromagnetic waves remains a significant challenge although it promises many important applications. Here, we proposed a fast optimization method of designing a wideband metasurface without using the Pancharatnam-Berry (PB) phase, of which the elements are non-absorptive and capable of predicting the wideband and smooth phase-shift. In our design method, the metasurface is composed of low-Q-factor resonant elements without using the PB phase, and is optimized by the genetic algorithm and nonlinear fitting method, having the advantages that the far field scattering patterns can be quickly synthesized by the hybrid array patterns. To validate the design method, a wideband low radar cross section metasurface is demonstrated, showing good feasibility and performance of wideband RCS reduction. This work reveals an opportunity arising from a metasurface in effective manipulation of microwave and flexible fast optimal design method.

  16. WISM - A Wideband Instrument for Snow Measurement: Past Accomplishments, Current Status, and Path Forward

    Science.gov (United States)

    Bonds, Quenton; Racette, Paul; Durham, Tim (Principal Investigator)

    2016-01-01

    Presented are the prior accomplishments, current status and path forward for GSFC's Wideband Instrument for Snow Measurement (WISM). This work is a high level overview of the project, presented via Webinar to the IEEE young professionals.

  17. Ultra-Wideband Transceiver for Integrated Communication and Relative Navigation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop an innovative way of using Time Modulated Ultra Wideband (TM-UWB) transceivers (radios) to provide high performance integrated...

  18. The design of wideband metamaterial absorber at E band based on defect

    Science.gov (United States)

    Wang, L. S.; Xia, D. Y.; Ding, X. Y.; Wang, Y.

    2018-01-01

    A kind of wideband metamaterial absorber at E band is designed in this paper; it is composed of round metal cells with defect, dielectric substrate and metal film. The electromagnetic parameters of unit cell are calculated by using the finite element method. The results show that the wideband metamaterial absorber presents nearly perfect absorption above 90% with absorption ranging from 65.38GHz to 67.86GHz; the reason of wideband absorption is the overlap of different absorption frequency which is caused by electromagnetic resonance; the size parameters and position of defect has important effect on its absorption property. It has many advantages, such as simply, easy to preparation and so on. It has potential application on aerospace measurement and control, remote data communication, LTE wideband mobile communication and other fields.

  19. Design of a High Linearity Four-Quadrant Analog Multiplier in Wideband Frequency Range

    Directory of Open Access Journals (Sweden)

    Abdul kareem Mokif Obais

    2017-05-01

    Full Text Available In this paper, a voltage mode four quadrant analog multiplier in the wideband frequency rangeis designed using a wideband operational amplifier (OPAMP and squaring circuits. The wideband OPAMP is designed using 10 identical NMOS transistorsand operated with supply voltages of ±12V. Two NMOS transistors and two wideband OPAMP are utilized in the design of the proposed squaring circuit. All the NMOS transistors are based on 0.35µm NMOStechnology. The multiplier has input and output voltage ranges of ±10 V, high range of linearity from -10 V to +10 V, and cutoff frequency of about 5 GHz. The proposed multiplier is designed on PSpice in Orcad 16.6

  20. A Dual Stage Linear Prediction Approach Towards Wideband FM Demodulation With Multilevel and Partial Response Signaling

    Science.gov (United States)

    2018-01-19

    attributed to the inherent interpolation process in the MFT demodulation approach, which is more error-sensitive to discontinuous waveforms, such as...Multirate Frequency Transformations In the author’s recent work, frequency transformations enacted via multirate signal processing were used for wideband...FM to narrowband FM conversion to enable a wider range of wideband FM signals [9, 11]. The goal of the multirate processing module is to compress the

  1. Wideband noise observed at ground level in the auroral region

    International Nuclear Information System (INIS)

    Benson, R.F.; Desch, M.D.

    1991-01-01

    A sideband noise event was detected at ground level from the Andoya Rocket Range in Norway in January 1989. The signals were observed on four commercial communication receivers (tuned to 159, 515, 905, and 1200 kHz), an ionosonde (200-kHz to 3.5-MHz interference-free observations) and a riometer (32.5 MHz). The event, which occurred during a period of magnetic disturbance near magnetic midnight, was the only one observed during nearly 3 weeks of operations. This low frequency-of-occurrence is attributed partly to high local noise levels. The ease with which this event was identified on the ionograms produced by the local ionosonde suggests that routine ionosonde recordings should be inspected in search for such events. Such an effort would enhance existing research directed toward developing techniques for identifying quiet communication channels and help to identify the origin and frequency-of-occurrence of high-latitude wideband noise events. 20 refs

  2. A GPU-Based Wide-Band Radio Spectrometer

    Science.gov (United States)

    Chennamangalam, Jayanth; Scott, Simon; Jones, Glenn; Chen, Hong; Ford, John; Kepley, Amanda; Lorimer, D. R.; Nie, Jun; Prestage, Richard; Roshi, D. Anish; Wagner, Mark; Werthimer, Dan

    2014-12-01

    The graphics processing unit has become an integral part of astronomical instrumentation, enabling high-performance online data reduction and accelerated online signal processing. In this paper, we describe a wide-band reconfigurable spectrometer built using an off-the-shelf graphics processing unit card. This spectrometer, when configured as a polyphase filter bank, supports a dual-polarisation bandwidth of up to 1.1 GHz (or a single-polarisation bandwidth of up to 2.2 GHz) on the latest generation of graphics processing units. On the other hand, when configured as a direct fast Fourier transform, the spectrometer supports a dual-polarisation bandwidth of up to 1.4 GHz (or a single-polarisation bandwidth of up to 2.8 GHz).

  3. Calculations of a wideband metamaterial absorber using equivalent medium theory

    Science.gov (United States)

    Huang, Xiaojun; Yang, Helin; Wang, Danqi; Yu, Shengqing; Lou, Yanchao; Guo, Ling

    2016-08-01

    Metamaterial absorbers (MMAs) have drawn increasing attention in many areas due to the fact that they can achieve electromagnetic (EM) waves with unity absorptivity. We demonstrate the design, simulation, experiment and calculation of a wideband MMA based on a loaded double-square-loop (DSL) array of chip resisters. For a normal incidence EM wave, the simulated results show that the absorption of the full width at half maximum is about 9.1 GHz, and the relative bandwidth is 87.1%. Experimental results are in agreement with the simulations. More importantly, equivalent medium theory (EMT) is utilized to calculate the absorptions of the DSL MMA, and the calculated absorptions based on EMT agree with the simulated and measured results. The method based on EMT provides a new way to analysis the mechanism of MMAs.

  4. Resilience of LTE networks against smart jamming attacks: Wideband model

    KAUST Repository

    Aziz, Farhan M.

    2015-12-03

    LTE/LTE-A networks have been successfully providing advanced broadband services to millions of users worldwide. Lately, it has been suggested to use LTE networks for mission-critical applications like public safety, smart grid and military communications. We have previously shown that LTE networks are vulnerable to Denial-of-Service (DOS) and loss of service attacks from smart jammers. In this paper, we extend our previous work on resilience of LTE networks to wideband multipath fading channel, SINR estimation in frequency domain and computation of utilities based on observable parameters under the framework of single-shot and repeated games with asymmetric information. In a single-shot game formulation, network utility is severely compromised at its solutions, i.e. at the Nash Equilibria (NE). We propose evolved repeated-game strategy algorithms to combat smart jamming attacks that can be implemented in existing deployments using current technology. © 2015 IEEE.

  5. Improvement of acoustical characteristics : wideband bamboo based polymer composite

    Science.gov (United States)

    Farid, M.; Purniawan, A.; Rasyida, A.; Ramadhani, M.; Komariyah, S.

    2017-07-01

    Environmental friendly and comfortable materials are desirable for applications in the automobile interior. The objective of this research was to examine and develop bamboo based polymer composites applied to the sound absorption materials of automobile door panels. Morphological analysis of the polyurethane/bamboo powder composite materials was carried out using scanning electron microscope to reveal the microscopic material behavior and followed by the FTIR and TGA testing. The finding demonstrated that this acoustical polymer composite materials provided a potential wideband sound absorption material. The range of frequency can be controlled between 500 and 4000 Hz with an average of sound absorption coefficient around 0.411 and it met to the door panels criteria.

  6. Wideband and UWB Antennas for Wireless Applications: A Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Renato Cicchetti

    2017-01-01

    Full Text Available A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible, and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc. and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems.

  7. A Novel Ropes-DrivenWideband Piezoelectric Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Jinhui Zhang

    2016-12-01

    Full Text Available This paper presents a novel piezoelectric vibration energy harvester (PVEH in which a high-frequency generating beam (HFGB is driven by an array of low-frequency driving beams (LFDBs using ropes. Two mechanisms based on frequency upconversion and multimodal harvesting work together to broaden the frequency bandwidth of the proposed vibration energy harvester (VEH. The experimental results show that the output power of generating beam (GB remains unchanged with the increasing number of driving beams (DBs, compared with the traditional arrays of beams vibration energy harvester (AB-VEH, and the output power and bandwidth behavior can be adjusted by parameters such as acceleration, rope margin, and stiffness of LFDBs, which shows the potential to achieve unlimited wideband vibration energy-harvesting for a variable environment.

  8. Ultra-wideband horn antenna with abrupt radiator

    Science.gov (United States)

    McEwan, Thomas E.

    1998-01-01

    An ultra-wideband horn antenna transmits and receives impulse waveforms for short-range radars and impulse time-of flight systems. The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna. Dispersion is minimized with an abrupt launch point radiator element; sidelobe and feedline coupling are minimized by recessing the radiator into a metallic horn. Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies. A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn. The launcher plate and feed plate join at an abrupt edge which forms the single launch point of the antenna.

  9. DATA QUALITY EVALUATION AND APPLICATION POTENTIAL ANALYSIS OF TIANGONG-2 WIDE-BAND IMAGING SPECTROMETER

    Directory of Open Access Journals (Sweden)

    B. Qin

    2018-04-01

    Full Text Available Tiangong-2 is the first space laboratory in China, which launched in September 15, 2016. Wide-band Imaging Spectrometer is a medium resolution multispectral imager on Tiangong-2. In this paper, the authors introduced the indexes and parameters of Wideband Imaging Spectrometer, and made an objective evaluation about the data quality of Wide-band Imaging Spectrometer in radiation quality, image sharpness and information content, and compared the data quality evaluation results with that of Landsat-8. Although the data quality of Wide-band Imager Spectrometer has a certain disparity with Landsat-8 OLI data in terms of signal to noise ratio, clarity and entropy. Compared with OLI, Wide-band Imager Spectrometer has more bands, narrower bandwidth and wider swath, which make it a useful remote sensing data source in classification and identification of large and medium scale ground objects. In the future, Wide-band Imaging Spectrometer data will be widely applied in land cover classification, ecological environment assessment, marine and coastal zone monitoring, crop identification and classification, and other related areas.

  10. Data Quality Evaluation and Application Potential Analysis of TIANGONG-2 Wide-Band Imaging Spectrometer

    Science.gov (United States)

    Qin, B.; Li, L.; Li, S.

    2018-04-01

    Tiangong-2 is the first space laboratory in China, which launched in September 15, 2016. Wide-band Imaging Spectrometer is a medium resolution multispectral imager on Tiangong-2. In this paper, the authors introduced the indexes and parameters of Wideband Imaging Spectrometer, and made an objective evaluation about the data quality of Wide-band Imaging Spectrometer in radiation quality, image sharpness and information content, and compared the data quality evaluation results with that of Landsat-8. Although the data quality of Wide-band Imager Spectrometer has a certain disparity with Landsat-8 OLI data in terms of signal to noise ratio, clarity and entropy. Compared with OLI, Wide-band Imager Spectrometer has more bands, narrower bandwidth and wider swath, which make it a useful remote sensing data source in classification and identification of large and medium scale ground objects. In the future, Wide-band Imaging Spectrometer data will be widely applied in land cover classification, ecological environment assessment, marine and coastal zone monitoring, crop identification and classification, and other related areas.

  11. Food in the Schools, Part I. Options in Education, Program #75.

    Science.gov (United States)

    George Washington Univ., Washington, DC. Inst. for Educational Leadership.

    This document presents the program transcripts of a weekly series broadcast by member stations of National Public Radio. The program focuses on food in the schools. It addresses the following issues: plate waste in Chicago and Dallas; banning junk food and vending machines; the results of a vending machine junk food ban in West Virginia;…

  12. Van die Redaksie/Editorial

    African Journals Online (AJOL)

    bread is a basic foodstuff, but biscuits are junk; wine comprises ... White bread is not. 'nutritious', but cauliflower is, although it consists of. 90% water, 5% starch, a minute amount of protein, and only traces of vitamins and minerals (other than potas- sium). ... The alter- native definition is therefore that junk or non-nutritious.

  13. Listening to Historys Rhyme:Preparing the United States Army for Future Irregular Warfare

    Science.gov (United States)

    2014-04-01

    December 2007), 10. 44. Mission: Readiness, Too Fat to Fight: Retired Military Leaders Want Junk Food Out of Schools (Washington, DC, April 2010), 2...Politics and Strategy 50, no. 1 (February-March 2008): 19-30. Mission: Readiness. Too Fat to Fight: Retired Military Leaders Want Junk Food Out

  14. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development: Study of the Optical Setup of a Wide-Band Optical Modulation Spectrometer

    Science.gov (United States)

    Tolls, Volker; Stringfellow, Guy (Technical Monitor)

    2001-01-01

    The purpose of this study is to advance the design of the optical setup for a wide-band Optical Modulation Spectrometer (OMS) for use with astronomical heterodyne receiver systems. This report describes the progress of this investigation achieved from March until December 2001.

  15. First results from the Cluster wideband plasma wave investigation

    Directory of Open Access Journals (Sweden)

    D. A. Gurnett

    2001-09-01

    Full Text Available In this report we present the first results from the Cluster wideband plasma wave investigation. The four Cluster spacecraft were successfully placed in closely spaced, high-inclination eccentric orbits around the Earth during two separate launches in July – August 2000. Each spacecraft includes a wideband plasma wave instrument designed to provide high-resolution electric and magnetic field wave-forms via both stored data and direct downlinks to the NASA Deep Space Network. Results are presented for three commonly occurring magnetospheric plasma wave phenomena: (1 whistlers, (2 chorus, and (3 auroral kilometric radiation. Lightning-generated whistlers are frequently observed when the spacecraft is inside the plasmasphere. Usually the same whistler can be detected by all spacecraft, indicating that the whistler wave packet extends over a spatial dimension at least as large as the separation distances transverse to the magnetic field, which during these observations were a few hundred km. This is what would be expected for nonducted whistler propagation. No case has been found in which a strong whistler was detected at one spacecraft, with no signal at the other spacecraft, which would indicate ducted propagation. Whistler-mode chorus emissions are also observed in the inner region of the magnetosphere. In contrast to lightning-generated whistlers, the individual chorus elements seldom show a one-to-one correspondence between the spacecraft, indicating that a typical chorus wave packet has dimensions transverse to the magnetic field of only a few hundred km or less. In one case where a good one-to-one correspondence existed, significant frequency variations were observed between the spacecraft, indicating that the frequency of the wave packet may be evolving as the wave propagates. Auroral kilometric radiation, which is an intense radio emission generated along the auroral field lines, is frequently observed over the polar regions. The

  16. First results from the Cluster wideband plasma wave investigation

    Directory of Open Access Journals (Sweden)

    D. A. Gurnett

    Full Text Available In this report we present the first results from the Cluster wideband plasma wave investigation. The four Cluster spacecraft were successfully placed in closely spaced, high-inclination eccentric orbits around the Earth during two separate launches in July – August 2000. Each spacecraft includes a wideband plasma wave instrument designed to provide high-resolution electric and magnetic field wave-forms via both stored data and direct downlinks to the NASA Deep Space Network. Results are presented for three commonly occurring magnetospheric plasma wave phenomena: (1 whistlers, (2 chorus, and (3 auroral kilometric radiation. Lightning-generated whistlers are frequently observed when the spacecraft is inside the plasmasphere. Usually the same whistler can be detected by all spacecraft, indicating that the whistler wave packet extends over a spatial dimension at least as large as the separation distances transverse to the magnetic field, which during these observations were a few hundred km. This is what would be expected for nonducted whistler propagation. No case has been found in which a strong whistler was detected at one spacecraft, with no signal at the other spacecraft, which would indicate ducted propagation. Whistler-mode chorus emissions are also observed in the inner region of the magnetosphere. In contrast to lightning-generated whistlers, the individual chorus elements seldom show a one-to-one correspondence between the spacecraft, indicating that a typical chorus wave packet has dimensions transverse to the magnetic field of only a few hundred km or less. In one case where a good one-to-one correspondence existed, significant frequency variations were observed between the spacecraft, indicating that the frequency of the wave packet may be evolving as the wave propagates. Auroral kilometric radiation, which is an intense radio emission generated along the auroral field lines, is frequently observed over the polar regions. The

  17. Time-stretch microscopy based on time-wavelength sequence reconstruction from wideband incoherent source

    International Nuclear Information System (INIS)

    Zhang, Chi; Xu, Yiqing; Wei, Xiaoming; Tsia, Kevin K.; Wong, Kenneth K. Y.

    2014-01-01

    Time-stretch microscopy has emerged as an ultrafast optical imaging concept offering the unprecedented combination of the imaging speed and sensitivity. However, dedicated wideband and coherence optical pulse source with high shot-to-shot stability has been mandated for time-wavelength mapping—the enabling process for ultrahigh speed wavelength-encoded image retrieval. From the practical point of view, exploiting methods to relax the stringent requirements (e.g., temporal stability and coherence) for the source of time-stretch microscopy is thus of great value. In this paper, we demonstrated time-stretch microscopy by reconstructing the time-wavelength mapping sequence from a wideband incoherent source. Utilizing the time-lens focusing mechanism mediated by a narrow-band pulse source, this approach allows generation of a wideband incoherent source, with the spectral efficiency enhanced by a factor of 18. As a proof-of-principle demonstration, time-stretch imaging with the scan rate as high as MHz and diffraction-limited resolution is achieved based on the wideband incoherent source. We note that the concept of time-wavelength sequence reconstruction from wideband incoherent source can also be generalized to any high-speed optical real-time measurements, where wavelength is acted as the information carrier

  18. Fast switching wideband rectifying circuit for future RF energy harvesting

    Science.gov (United States)

    Asmeida, Akrem; Mustam, Saizalmursidi Md; Abidin, Z. Z.; Ashyap, A. Y. I.

    2017-09-01

    This paper presents the design and simulation of fast switching microwave rectifying circuit for ultra wideband patch antenna over a dual-frequency band (1.8 GHz for GSM and 2.4 GHz for ISM band). This band was chosen due to its high signal availability in the surrounding environment. New rectifying circuit topology with pair-matching trunks is designed using Advanced Design System (ADS) software. These trunks are interfaced with power divider to achieve good bandwidth, fast switching and high efficiency. The power divider acts as a good isolator between the trunks and its straightforward design structure makes it a good choice for a single feed UWB antenna. The simulated results demonstrate that the maximum output voltage is 2.13 V with an input power of -5 dBm. Moreover, the rectifier offers maximum efficiency of 86% for the input power of -5 dBm at given band, which could easily power up wireless sensor networks (WSN) and other small devices sufficiently.

  19. PERFORMANCE OPTIMIZATION OF COGNITIVE RADIO WITH WIDEBAND SPECTRUM SENSING

    Directory of Open Access Journals (Sweden)

    E. Saraniya

    2014-09-01

    Full Text Available Cognitive radio (CR technology allows the unlicensed user to access the licensed spectrum bands. Spectrum sensing is an essential function in cognitive radio to detect the spectrum holes and opportunistically use the underutilized frequency bands without causing interference to primary user (PU. In this paper we are maximizing the throughput capacity of cognitive radio user and hence the performance of spectrum sensing and protection to licensed user improves over a wideband spectrum sensing band. The simulation of cognitive radio is done by analyzing the performance of energy detector spectrum sensing technique to detect primary user and to formulate the optimization using multiband joint detection method (MJD to achieve suitable trade- off between secondary user access and primary user network. The main aim of this paper is to maximize the probability of detection and to decrease the probabilities of miss detection and false alarm. To maximize the throughput it requires minimizing the throughput loss caused by miss detection and the significant reduction in probability of false alarm helps in achieving the spectral efficiency from the secondary user’s perspective. The simulation results show that the performance increases with the MJD method.

  20. Sensing RF signals with the optical wideband converter

    Science.gov (United States)

    Valley, George C.; Sefler, George A.; Shaw, T. J.

    2013-01-01

    The optical wideband converter (OWC) is a system for measuring properties of RF signals in the GHz band without use of high speed electronics. In the OWC the RF signal is modulated on a repetitively pulsed optical field with a large wavelength chirp, the optical field is diffracted onto a spatial light modulator (SLM) whose pixels are modulated with a pseudo-random bit sequences (PRBSs), and finally the optical field is directed to a photodiode and the resulting current integrated for each PRBS. When the number of PRBSs and measurements equals the number of SLM pixels, the RF signal can be obtained in principle by multiplying the measurement vector by the inverse of the square matrix given by the PRBSs and the properties of the optics. When the number of measurements is smaller than the number of pixels, a compressive sensing (CS) measurement can be performed, and sparse RF signals can be obtained using one of the standard CS recovery algorithms such as the penalized l1 norm (also known as basis pursuit) or one of the variants of matching pursuit. Accurate reconstruction of RF signals requires good calibration of the OWC. In this paper, we present results using the OWC for RF signals consisting of 2 sinusoids recovered using 3 techniques (matrix inversion, basis pursuit, and matching pursuit). We compare results obtained with orthogonal matching pursuit with nonlinear least squares to basis pursuit with an over-complete dictionary.

  1. Ultra-wideband spectral analysis using S2 technology

    International Nuclear Information System (INIS)

    Krishna Mohan, R.; Chang, T.; Tian, M.; Bekker, S.; Olson, A.; Ostrander, C.; Khallaayoun, A.; Dollinger, C.; Babbitt, W.R.; Cole, Z.; Reibel, R.R.; Merkel, K.D.; Sun, Y.; Cone, R.; Schlottau, F.; Wagner, K.H.

    2007-01-01

    This paper outlines the efforts to develop an ultra-wideband spectrum analyzer that takes advantage of the broad spectral response and fine spectral resolution (∼25 kHz) of spatial-spectral (S2) materials. The S2 material can process the full spectrum of broadband microwave transmissions, with adjustable time apertures (down to 100 μs) and fast update rates (up to 1 kHz). A cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm is used as the core for the spectrum analyzer. Efforts to develop novel component technologies that enhance the performance of the system and meet the application requirements are discussed, including an end-to-end device model for parameter optimization. We discuss the characterization of new ultra-wide bandwidth S2 materials. Detection and post-processing module development including the implementation of a novel spectral recovery algorithm using field programmable gate array technology (FPGA) is also discussed

  2. Principles and Limitations of Ultra-Wideband FM Communications Systems

    Directory of Open Access Journals (Sweden)

    Kouwenhoven Michiel HL

    2005-01-01

    Full Text Available This paper presents a novel UWB communications system using double FM: a low-modulation index digital FSK followed by a high-modulation index analog FM to create a constant-envelope UWB signal. FDMA techniques at the subcarrier level are exploited to accommodate multiple users. The system is intended for low (1–10 kbps and medium (100–1000 kbps bit rate, and short-range WPAN systems. A wideband delay-line FM demodulator that is not preceded by any limiting amplifier constitutes the key component of the UWBFM receiver. This unusual approach permits multiple users to share the same RF bandwidth. Multipath, however, may limit the useful subcarrier bandwidth to one octave. This paper addresses the performance with AWGN and multipath, the resistance to narrowband interference, as well as the simultaneous detection of multiple FM signals at the same carrier frequency. SPICE and Matlab simulation results illustrate the principles and limitations of this new technology. A hardware demonstrator has been realized and has allowed the confirmation of theory with practical results.

  3. Interference Mitigation for Coexistence of Heterogeneous Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    Wu Haitao

    2006-01-01

    Full Text Available Two ultra-wideband (UWB specifications, that is, direct-sequence (DS UWB and multiband-orthogonal frequency division multiplexing (MB-OFDM UWB, have been proposed as the candidates of the IEEE 802.15.3a, competing for the standard of high-speed wireless personal area networks (WPAN. Due to the withdrawal of the standardization process, the two heterogeneous UWB technologies will coexist in the future commercial market. In this paper, we investigate the mutual interference of such coexistence scenarios by physical layer Monte Carlo simulations. The results reveal that the coexistence severely degrades the performance of both UWB systems. Moreover, such interference is asymmetric due to the heterogeneity of the two systems. Therefore, we propose the goodput-oriented utility-based transmit power control (GUTPC algorithm for interference mitigation. The feasible condition and the convergence property of GUTPC are investigated, and the choice of the coefficients is discussed for fairness and efficiency. Numerical results demonstrate that GUTPC improves the goodput of the coexisting systems effectively and fairly with saved power.

  4. Time-Domain Diversity in Ultra-Wideband MIMO Communications

    Directory of Open Access Journals (Sweden)

    Alain Sibille

    2005-03-01

    Full Text Available The development of ultra-wideband (UWB communications is impeded by the drastic transmitted power limitations imposed by regulation authorities due to the “polluting” character of these radio emissions with respect to existing services. Technical solutions must be researched in order either to limit the level of spectral pollution by UWB devices or to increase their reception sensitivity. In the present work, we consider pulse-based modulations and investigate time-domain multiple-input multiple-output (MIMO diversity as one such possible solution. The basic principles of time-domain diversity in the extreme (low multipath density or intermediate (dense multipath UWB regimes are addressed, which predict the possibility of a MIMO gain equal to the product Nt×Nr of the numbers of transmit/receive antenna elements when the channel is not too severe. This analysis is confirmed by simulations using a parametric empirical stochastic double-directional channel model. They confirm the potential interest of MIMO approaches solutions in order to bring a valuable performance gain in UWB communications.

  5. Ultra-wideband spectral analysis using S2 technology

    Energy Technology Data Exchange (ETDEWEB)

    Krishna Mohan, R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)]. E-mail: krishna@spectrum.montana.edu; Chang, T. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Tian, M. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Bekker, S. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Olson, A. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Ostrander, C. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Khallaayoun, A. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Dollinger, C. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Cole, Z. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); S2 Corporation, Bozeman, MT 59718 (United States); Reibel, R.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); S2 Corporation, Bozeman, MT 59718 (United States); Merkel, K.D. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); S2 Corporation, Bozeman, MT 59718 (United States); Sun, Y. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Cone, R. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Schlottau, F. [University of Colorado, Boulder, CO 80309 (United States); Wagner, K.H. [University of Colorado, Boulder, CO 80309 (United States)

    2007-11-15

    This paper outlines the efforts to develop an ultra-wideband spectrum analyzer that takes advantage of the broad spectral response and fine spectral resolution ({approx}25 kHz) of spatial-spectral (S2) materials. The S2 material can process the full spectrum of broadband microwave transmissions, with adjustable time apertures (down to 100 {mu}s) and fast update rates (up to 1 kHz). A cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm is used as the core for the spectrum analyzer. Efforts to develop novel component technologies that enhance the performance of the system and meet the application requirements are discussed, including an end-to-end device model for parameter optimization. We discuss the characterization of new ultra-wide bandwidth S2 materials. Detection and post-processing module development including the implementation of a novel spectral recovery algorithm using field programmable gate array technology (FPGA) is also discussed.

  6. Wideband energy harvesting based on mixed connection of piezoelectric oscillators

    Science.gov (United States)

    Wu, P. H.; Chen, Y. J.; Li, B. Y.; Shu, Y. C.

    2017-09-01

    An approach for wideband energy harvesting together with power enhancement is proposed by integrating multiple piezoelectric oscillators with mixed parallel-series connection. This gives rise to the feasibility of shifting the operation frequency band to the dominant frequency domain of ambient excitations. There are two types of connection patterns discussed here: the p-type (s-type) is the parallel (series) connection of all sets of oscillators where some of them may be connected in series (parallel). In addition, the standard interface circuit used for electric rectification is adopted here. The analytic estimates of output power are derived and explicitly expressed in terms of different matrix formulations for these two connection patterns. They are subsequently validated and are found in good agreement with numerical simulations and experimental observations. Finally, the experimental results from the mixed connection of 4 piezoelectric oscillators show that the peak power of each array is about 3.4 times higher than that generated by a single piezoelectric oscillator. In addition, the bandwidth of the array capable of switching connection patterns is around 2.8 times wider than that based on a single array configuration. Hence, the effective bandwidth is enlarged without the loss of peak power.

  7. Optimization of Planar Monopole Wideband Antenna for Wireless Communication System.

    Science.gov (United States)

    Shakib, Mohammed Nazmus; Moghavvemi, Mahmoud; Mahadi, Wan Nor Liza

    2016-01-01

    In this paper, a new compact wideband monopole antenna is presented for wireless communication applications. This antenna comprises of a new radiating patch, a new arc-shaped strip, microstrip feed line, and a notched ground plane. The proposed radiating patch is combined with a rectangular and semi-circular patch and is integrated with a partial ground plane to provide a wide impedance bandwidth. The new arc-shaped strip between the radiating patch and microstrip feed line creates an extra surface on the patch, which helps further widen the bandwidth. Inserting one step notch on the ground plane further enhances the bandwidth. The antenna has a compact size of 16×20×1.6mm3. The measured result indicated that the antenna achieves a 127% bandwidth at VSWR≤2, ranging from 4.9GHz to 22.1GHz. Stable radiation patterns with acceptable gain are achieved. Also, a measured bandwidth of 107.7% at VSWR≤1.5 (5.1-17GHz) is obtained, which is suitable for UWB outdoor propagation. This antenna is compatible with a good number of wireless standards, including UWB band, Wimax 5.4 GHz band, MVDDS (12.2-12.7GHz), and close range radar and satellite communication in the X-band (8-12GHz), and Ku band (12-18GHz).

  8. Ultra Wideband Indoor Positioning Technologies: Analysis and Recent Advances.

    Science.gov (United States)

    Alarifi, Abdulrahman; Al-Salman, AbdulMalik; Alsaleh, Mansour; Alnafessah, Ahmad; Al-Hadhrami, Suheer; Al-Ammar, Mai A; Al-Khalifa, Hend S

    2016-05-16

    In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. In comparison with outdoor environments, sensing location information in indoor environments requires a higher precision and is a more challenging task in part because various objects reflect and disperse signals. Ultra WideBand (UWB) is an emerging technology in the field of indoor positioning that has shown better performance compared to others. In order to set the stage for this work, we provide a survey of the state-of-the-art technologies in indoor positioning, followed by a detailed comparative analysis of UWB positioning technologies. We also provide an analysis of strengths, weaknesses, opportunities, and threats (SWOT) to analyze the present state of UWB positioning technologies. While SWOT is not a quantitative approach, it helps in assessing the real status and in revealing the potential of UWB positioning to effectively address the indoor positioning problem. Unlike previous studies, this paper presents new taxonomies, reviews some major recent advances, and argues for further exploration by the research community of this challenging problem space.

  9. Wideband quin-stable energy harvesting via combined nonlinearity

    Directory of Open Access Journals (Sweden)

    Chen Wang

    2017-04-01

    Full Text Available In this work, we propose a wideband quintuple-well potential piezoelectric-based vibration energy harvester using a combined nonlinearity: the magnetic nonlinearity induced by magnetic force and the piecewise-linearity produced by mechanical impact. With extra stable states compared to other multi-stable harvesters, the quin-stable harvester can distribute its potential energy more uniformly, which provides shallower potential wells and results in lower excitation threshold for interwell motion. The mathematical model of this quin-stable harvester is derived and its equivalent piecewise-nonlinear restoring force is measured in the experiment and identified as piecewise polynomials. Numerical simulations and experimental verifications are performed in different levels of sinusoid excitation ranging from 1 to 25 Hz. The results demonstrate that, with lower potential barriers compared with tri-stable counterpart, the quin-stable arrangement can escape potential wells more easily for doing high-energy interwell motion over a wider band of frequencies. Moreover, by utilizing the mechanical stoppers, this harvester can produce significant output voltage under small tip deflections, which results in a high power density and is especially suitable for a compact MEMS approach.

  10. Ultra Wideband Indoor Positioning Technologies: Analysis and Recent Advances †

    Science.gov (United States)

    Alarifi, Abdulrahman; Al-Salman, AbdulMalik; Alsaleh, Mansour; Alnafessah, Ahmad; Al-Hadhrami, Suheer; Al-Ammar, Mai A.; Al-Khalifa, Hend S.

    2016-01-01

    In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. In comparison with outdoor environments, sensing location information in indoor environments requires a higher precision and is a more challenging task in part because various objects reflect and disperse signals. Ultra WideBand (UWB) is an emerging technology in the field of indoor positioning that has shown better performance compared to others. In order to set the stage for this work, we provide a survey of the state-of-the-art technologies in indoor positioning, followed by a detailed comparative analysis of UWB positioning technologies. We also provide an analysis of strengths, weaknesses, opportunities, and threats (SWOT) to analyze the present state of UWB positioning technologies. While SWOT is not a quantitative approach, it helps in assessing the real status and in revealing the potential of UWB positioning to effectively address the indoor positioning problem. Unlike previous studies, this paper presents new taxonomies, reviews some major recent advances, and argues for further exploration by the research community of this challenging problem space. PMID:27196906

  11. Wide-band neutrino beams at 1000 GeV

    International Nuclear Information System (INIS)

    Malensek, A.; Stutte, L.

    1983-01-01

    In a previous publication, S. Mori discussed various broad-band neutrino and antineutrino beams using 1000 GeV protons on target. A new beam (SST) has been designed which provides the same neutrino flux as the quadrupole triplet (QT) while suppressing the wrong sign flux by a factor of 18. It also provides more than twice as much high energy antineutrino flux than the sign-selected bare target (SSBT) and in addition, has better neutrino suppression. While it is possible to increase the flux obtained from the single horn system over that previously described, the conclusion which states any horn focussing system seems to be of marginal use for Tevatron neutrino physics, is unchanged. Neutrino and antineutrino event rates and wrong sign backgrounds were computed using NUADA for a 100 metric ton detector of radius 1.5 meters. Due to radiation considerations and the existing transformer location, the horn beam is placed in its usual position inside the Target Tube. All other beams are placed in Fronthall. Thus, for the wide-band Fronthall trains a decay distance of 520 meters is used, versus 400 meters for the horn train

  12. Digital Receiver Design for Transmitted Reference Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    Wang Yiyin

    2009-01-01

    Full Text Available Abstract A complete detection, channel estimation, synchronization, and equalization scheme for a transmitted reference (TR ultra-wideband (UWB system is proposed in this paper. The scheme is based on a data model which admits a moderate data rate and takes both the interframe interference (IFI and the intersymbol interference (ISI into consideration. Moreover, the bias caused by the interpulse interference (IPI in one frame is also taken into account. Based on the analysis of the stochastic properties of the received signals, several detectors are studied and evaluated. Furthermore, a data-aided two-stage synchronization strategy is proposed, which obtains sample-level timing in the range of one symbol at the first stage and then pursues symbol-level synchronization by looking for the header at the second stage. Three channel estimators are derived to achieve joint channel and timing estimates for the first stage, namely, the linear minimum mean square error (LMMSE estimator, the least squares (LS estimator, and the matched filter (MF. We check the performance of different combinations of channel estimation and equalization schemes and try to find the best combination, that is, the one providing a good tradeoff between complexity and performance.

  13. Digital Receiver Design for Transmitted Reference Ultra-Wideband Systems

    Directory of Open Access Journals (Sweden)

    Yiyin Wang

    2009-01-01

    Full Text Available A complete detection, channel estimation, synchronization, and equalization scheme for a transmitted reference (TR ultra-wideband (UWB system is proposed in this paper. The scheme is based on a data model which admits a moderate data rate and takes both the interframe interference (IFI and the intersymbol interference (ISI into consideration. Moreover, the bias caused by the interpulse interference (IPI in one frame is also taken into account. Based on the analysis of the stochastic properties of the received signals, several detectors are studied and evaluated. Furthermore, a data-aided two-stage synchronization strategy is proposed, which obtains sample-level timing in the range of one symbol at the first stage and then pursues symbol-level synchronization by looking for the header at the second stage. Three channel estimators are derived to achieve joint channel and timing estimates for the first stage, namely, the linear minimum mean square error (LMMSE estimator, the least squares (LS estimator, and the matched filter (MF. We check the performance of different combinations of channel estimation and equalization schemes and try to find the best combination, that is, the one providing a good tradeoff between complexity and performance.

  14. Ultra-Wideband Tracking System Design for Relative Navigation

    Science.gov (United States)

    Ni, Jianjun David; Arndt, Dickey; Bgo, Phong; Dekome, Kent; Dusl, John

    2011-01-01

    This presentation briefly discusses a design effort for a prototype ultra-wideband (UWB) time-difference-of-arrival (TDOA) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being designed for use in localization and navigation of a rover in a GPS deprived environment for surface missions. In one application enabled by the UWB tracking, a robotic vehicle carrying equipments can autonomously follow a crewed rover from work site to work site such that resources can be carried from one landing mission to the next thereby saving up-mass. The UWB Systems Group at JSC has developed a UWB TDOA High Resolution Proximity Tracking System which can achieve sub-inch tracking accuracy of a target within the radius of the tracking baseline [1]. By extending the tracking capability beyond the radius of the tracking baseline, a tracking system is being designed to enable relative navigation between two vehicles for surface missions. A prototype UWB TDOA tracking system has been designed, implemented, tested, and proven feasible for relative navigation of robotic vehicles. Future work includes testing the system with the application code to increase the tracking update rate and evaluating the linear tracking baseline to improve the flexibility of antenna mounting on the following vehicle.

  15. Ultra-Wideband Printed Slot Radiators with Controllable Frequency Characteristics

    Directory of Open Access Journals (Sweden)

    S. L. Chernyshev

    2015-01-01

    Full Text Available We have studied the possibility of creating ultra-wideband (UWB antennas with controlled frequency response of matching based on the printed slot antenna Vivaldi by introducing controlled resonators directly into the structure of the radiator. In the area of irregular slotline there are printed switched resonators with variable capacitance (varactor model, which allow tuning the frequency characteristics for each state of switching cavities, providing bandpass and band-barrage properties of the antenna. The investigation of reconfigurable printed resonators in the system of reconfigurable resonators of a bandpass filter is conducted. The paper considers filter to provide restructuring in the band (3-9 GHz. Electrodynamic simulation of the device was carried out in the time domain using a finite integration method. A bandstop reconfigurable filter is also investigated. The filter located on the substrate opposite the slit is based on tunable L-shaped resonator that has one end connected to the short-circuitor through the board metallization; the other end remains open and is brought into the region of interaction with the slotline. Such filter provides an effective narrow-band suppression and can be easily tuned to the desired frequency channel. The combination of these two types of filters allows you to create a controlled print Vivaldi slot antenna with combined properties. The paper investigates parameters of the scattering and radiation pattern of the antenna in different modes.

  16. Ultra Wideband Indoor Positioning Technologies: Analysis and Recent Advances

    Directory of Open Access Journals (Sweden)

    Abdulrahman Alarifi

    2016-05-01

    Full Text Available In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. In comparison with outdoor environments, sensing location information in indoor environments requires a higher precision and is a more challenging task in part because various objects reflect and disperse signals. Ultra WideBand (UWB is an emerging technology in the field of indoor positioning that has shown better performance compared to others. In order to set the stage for this work, we provide a survey of the state-of-the-art technologies in indoor positioning, followed by a detailed comparative analysis of UWB positioning technologies. We also provide an analysis of strengths, weaknesses, opportunities, and threats (SWOT to analyze the present state of UWB positioning technologies. While SWOT is not a quantitative approach, it helps in assessing the real status and in revealing the potential of UWB positioning to effectively address the indoor positioning problem. Unlike previous studies, this paper presents new taxonomies, reviews some major recent advances, and argues for further exploration by the research community of this challenging problem space.

  17. A Wideband Channel Model for Intravehicular Nomadic Systems

    Directory of Open Access Journals (Sweden)

    François Bellens

    2011-01-01

    Full Text Available The increase in electronic entertainment equipments within vehicles has rendered the idea of replacing the wired links with intra-vehicle personal area networks. Ultra-wideband (UWB seems an appropriate candidate technology to meet the required data rates for interconnecting such devices. In particular, the multiband OFDM (MB-OFDM is able to provide very high transfer rates (up to 480 MBps over relatively short distances and low transmit power. In order to evaluate the performances of UWB systems within vehicles, a reliable channel model is needed. In this paper, a nomadic system where a base station placed in the center of the dashboard wants to communicate with fixed devices placed at the rear seat is investigated. A single-input single-output (SISO channel model for intra-vehicular communication (IVC systems is proposed, based on reverberation chamber theory. The model is based on measurements conducted in real traffic conditions, with a varying number of passengers in the car. Temporal variations of the wireless channels are also characterized and parametrized. The proposed model is validated by comparing model-independent statistics with the measurements.

  18. Instabilities simulations with wideband feedback systems: CMAD, HEADTAIL, WARP

    International Nuclear Information System (INIS)

    Li, Kevin; Cesaratto, J; Fox, J D; Pivi, M; Rivetta, C; Rumolo, G

    2013-01-01

    Transverse mode coupling (TMCI) and electron cloud instabilities (ECI) pose fundamental limitations on the acceptable beam intensities in the SPS at CERN. This in turn limits the ultimate achievable luminosity in the LHC. Therefore, future luminosity upgrades foresee methods for evading TMCI as well as ECI. Proposed approaches within the LHC Injector Upgrade (LIU) project include new optics with reduced transition energy as well as vacuum chamber coating techniques. As a complementary option, high bandwidth feedback systems may provide instability mitigation by actively damping the intra-bunch motion of unstable modes. In an effort to evaluate the potentials and limitations of such feedback systems and to characterise some of the specifications, a numerical model of a realistic feedback system has been developed and integrated into available instabilities simulation codes. Together with the implementation of this new feedback system model, CMAD and HEADTAIL have been used to investigate the impact of different wideband feedback systems on ECI in the SPS. In this paper, we present some details on the numerical model of the realistic feedback system and its implementation as well as the results obtained from the simulation study using this model together with the instability codes. (author)

  19. Methodology for Designing and Developing a New Ultra-Wideband Antenna Based on Bio-Inspired Optimization Techniques

    Science.gov (United States)

    2017-11-01

    on Bio -Inspired Optimization Techniques by Canh Ly, Nghia Tran, and Ozlem Kilic Approved for public release; distribution is...Research Laboratory Methodology for Designing and Developing a New Ultra-Wideband Antenna Based on Bio -Inspired Optimization Techniques by...SUBTITLE Methodology for Designing and Developing a New Ultra-Wideband Antenna Based on Bio -Inspired Optimization Techniques 5a. CONTRACT NUMBER

  20. Evaluation of strip-line pick-up system for the SPS wideband transverse feedback system

    CERN Document Server

    Kotzian, G; Steinhagen, R J; Valuch, D; Wehrle, U

    2017-01-01

    The proposed SPS Wideband Transverse Feedback sys- tem requires a wide-band pick-up system to be able to de- tect intra-bunch motion within the SPS proton bunches, captured and accelerated in a 200 MHz bucket. We present the electro-magnetic design of transverse beam position pick-up options optimised for installation in the SPS and evaluate their performance reach with respect to direct time domain sampling of the intra-bunch motion. The analy- sis also discusses the achieved subsystem responses of the associated cabling with new low dispersion smooth wall coaxial cables, wide-band generation of intensity and posi- tion signals by means of 180 degree RF hybrids as well as passive techniques to electronically suppress the beam off- set signal, needed to optimise the dynamic range and posi- tion resolution of the planned digital intra-bunch feedback system.

  1. An Ultra-wideband and Polarization-independent Metasurface for RCS Reduction.

    Science.gov (United States)

    Su, Pei; Zhao, Yongjiu; Jia, Shengli; Shi, Wenwen; Wang, Hongli

    2016-02-11

    In this paper, an ultra-wideband and polarization-independent metasurface for radar cross section (RCS) reduction is proposed. The unit cell of the metasurface operates in a linear cross-polarization scheme in a broad band. The phase and amplitude of cross-polarized reflection can be separately controlled by its geometry and rotation angle. Based on the diffuse reflection theory, a 3-bit coding metasurface is designed to reduce the RCS in an ultra-wide band. The wideband property of the metasurface benefits from the wideband cross polarization conversion and flexible phase modulation. In addition, the polarization-independent feature of the metasurface is achieved by tailoring the rotation angle of each element. Both the simulated and measured results demonstrate that the proposed metasurface can reduce the RCS significantly in an ultra-wide frequency band for both normal and oblique incidences, which makes it promising in the applications such as electromagnetic cloaking.

  2. A New Time-Hopping Multiple Access Communication System Simulator: Application to Ultra-Wideband

    Directory of Open Access Journals (Sweden)

    José M. Páez-Borrallo

    2005-03-01

    Full Text Available Time-hopping ultra-wideband technology presents some very attractive features for future indoor wireless systems in terms of achievable transmission rate and multiple access capabilities. This paper develops an algorithm to design time-hopping system simulators specially suitable for ultra-wideband, which takes advantage of some of the specific characteristics of this kind of systems. The algorithm allows an improvement of both the time capabilities and the achievable sampling rate and can be used to research into the influence of different parameters on the performance of the system. An additional result is the validation of a new general performance formula for time-hopping ultra-wideband systems with multipath channels.

  3. A Novel Compact Wideband TSA Array for Near-Surface Ice Sheet Penetrating Radar Applications

    Science.gov (United States)

    Zhang, Feng; Liu, Xiaojun; Fang, Guangyou

    2014-03-01

    A novel compact tapered slot antenna (TSA) array for near-surface ice sheet penetrating radar applications is presented. This TSA array is composed of eight compact antenna elements which are etched on two 480mm × 283mm FR4 substrates. Each antenna element is fed by a wideband coplanar waveguide (CPW) to coupled strip-line (CPS) balun. The two antenna substrates are connected together with a metallic baffle. To obtain wideband properties, another two metallic baffles are used along broadsides of the array. This array is fed by a 1 × 8 wideband power divider. The measured S11 of the array is less than -10dB in the band of 500MHz-2GHz, and the measured gain is more than 6dBi in the whole band which agrees well with the simulated results.

  4. Wideband propagation measurements at 30.3 GHz through a pecan orchard in Texas

    Science.gov (United States)

    Papazian, Peter B.; Jones, David L.; Espeland, Richard H.

    1992-09-01

    Wideband propagation measurements were made in a pecan orchard in Texas during April and August of 1990 to examine the propagation characteristics of millimeter-wave signals through vegetation. Measurements were made on tree obstructed paths with and without leaves. The study presents narrowband attenuation data at 9.6 and 28.8 GHz as well as wideband impulse response measurements at 30.3 GHz. The wideband probe (Violette et al., 1983), provides amplitude and delay of reflected and scattered signals and bit-error rate. This is accomplished using a 500 MBit/sec pseudo-random code to BPSK modulate a 28.8 GHz carrier. The channel impulse response is then extracted by cross correlating the received pseudo-random sequence with a locally generated replica.

  5. Design of an Ultra-wideband Pseudo Random Coded MIMO Radar Based on Radio Frequency Switches

    Directory of Open Access Journals (Sweden)

    Su Hai

    2017-02-01

    Full Text Available A Multiple-Input Multiple-Output (MIMO ultra-wideband radar can detect the range and azimuth information of targets in real time. It is widely used for geological surveys, life rescue, through-wall tracking, and other military or civil fields. This paper presents the design of an ultra-wideband pseudo random coded MIMO radar that is based on Radio Frequency (RF switches and implements a MIMO radar system. RF switches are employed to reduce cost and complexity of the system. As the switch pressure value is limited, the peak power of the transmitting signal is 18 dBm. The ultra-wideband radar echo is obtained by hybrid sampling, and pulse compression is computed by Digital Signal Processors (DSPs embedded in an Field-Programmable Gate Array (FPGA to simplify the signal process. The experiment illustrates that the radar system can detect the range and azimuth information of targets in real time.

  6. 8th conference on Ultra-Wideband Short-Pulse Electromagnetics

    CERN Document Server

    Tyo, J. Scott; Baum, Carl E; Ultra-Wideband Short-Pulse Electromagnetics 8; UWBSP8

    2007-01-01

    The purpose of the Ultra-Wideband Short-Pulse Electromagnetics Conference series is to focus on advanced technologies for the generation, radiation and detection of ultra-wideband short pulse signals, taking into account their propagation and scattering from and coupling to targets of interest. This Conference series reports on developments in supporting mathematical and numerical methods and presents current and potential future applications of the technology. Ultra-Wideband Short-Pulse Electromagnetics 8 is based on the American Electromagnetics 2006 conference held from June 3-7 in Albuquerque, New Mexico. Topical areas covered in this volume include pulse radiation and measurement, scattering theory, target detection and identification, antennas, signal processing, and communications.

  7. Reducing high calorie snack food in young adults: a role for social norms and health based messages.

    Science.gov (United States)

    Robinson, Eric; Harris, Ellis; Thomas, Jason; Aveyard, Paul; Higgs, Suzanne

    2013-06-05

    Consumption of high calorie junk foods has increased recently, especially among young adults and higher intake may cause weight gain. There is a need to develop public health approaches to motivate people to reduce their intake of junk food. To assess the effect of health and social norm messages on high calorie snack food intake (a type of junk food) as a function of usual intake of junk food. In a between-subjects design, 129 young adults (45 men and 84 women, mean age = 22.4 years, SD = 4.5) were assigned to one of three conditions: 1) a social norm condition, in which participants saw a message about the junk food eating habits of others; 2) a health condition, in which participants saw a message outlining the health benefits of reducing junk food consumption and; 3) a control condition, in which participants saw a non-food related message. After exposure to the poster messages, participants consumed a snack and the choice and amount of snack food consumed was examined covertly. We also examined whether usual intake of junk food moderated the effect of message type on high calorie snack food intake. The amount of high calorie snack food consumed was significantly lower in both the health and the social norm message condition compared with the control message condition (36% and 28%, both p food or energy intake between the health and social norm message conditions. There was no evidence that the effect of the messages depended upon usual consumption of junk food. Messages about the health effects of junk food and social normative messages about intake of junk food can motivate people to reduce their consumption of high calorie snack food.

  8. Design and Implementation of Wideband Exciter for an Ultra-high Resolution Airborne SAR System

    Directory of Open Access Journals (Sweden)

    Jia Ying-xin

    2013-03-01

    Full Text Available According to an ultra-high resolution airborne SAR system with better than 0.1 m resolution, a wideband Linear Frequency Modulated (LFM pulse compression exciter with 14.8 GHz carrier and 3.2 GHz bandwidth is designed and implemented. The selection of signal generation scheme and some key technique points for wideband LFM waveform is presented in detail. Then, an acute test and analysis of the LFM signal is performed. The final airborne experiments demonstrate the validity of the LFM source which is one of the subsystems in an ultra-high resolution airborne SAR system.

  9. Wideband Radar Echo Frequency-domain Simulation and Analysis for High Speed Moving Targets

    Directory of Open Access Journals (Sweden)

    Ning Chao

    2014-04-01

    Full Text Available A frequency-domain method is proposed for wideband radar echo simulation of high-speed moving targets. Based on the physical process of electromagnetic waves observing a moving target, a frequency-domain echo model of wideband radar is constructed, and the block diagram of the radar echo simulation in frequency-domain is presented. Then, the impacts of radial velocity and slant range on the matching filtering of LFM radar are analyzed, and some quantitative conclusions on the shift and expansion of the radar profiles are obtained. Simulation results illustrate the correctness and efficiency of the proposed method.

  10. Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide

    DEFF Research Database (Denmark)

    Xiao, Binggang; Li, Sheng-Hua; Xiao, Sanshui

    2016-01-01

    Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide is proposed. Owing to subwavelength confinement, such a filter has advantage in the structure size without sacrificing the performance. The spoof SPP based notch is introduced to suppress the WLAN and satel......Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide is proposed. Owing to subwavelength confinement, such a filter has advantage in the structure size without sacrificing the performance. The spoof SPP based notch is introduced to suppress the WLAN...

  11. Wideband Dual-Polarization Patch Antenna Array With Parallel Strip Line Balun Feeding

    DEFF Research Database (Denmark)

    Zhang, Jin; Lin, Xianqi; Nie, Liying

    2016-01-01

    A wideband dual-polarization patch antenna array is proposed in this letter. The array is fed by a parallel strip line balun, which is adopted to generate 180° phase shift in a wide frequency range. In addition, this balun has simple structure, very small phase shift error, and good ports isolati...... is higher than 30 dB. The simulation and measurement turns out to be similar. This antenna array can be used in TD-LTE base stations, and the design methods are also useful to other wideband microstrip antennas....

  12. Novel wideband MIMO antennas that can cover the whole LTE spectrum in handsets and portable computers.

    Science.gov (United States)

    Sanad, Mohamed; Hassan, Noha

    2014-01-01

    A dual resonant antenna configuration is developed for multistandard multifunction mobile handsets and portable computers. Only two wideband resonant antennas can cover most of the LTE spectrums in portable communication equipment. The bandwidth that can be covered by each antenna exceeds 70% without using any matching or tuning circuits, with efficiencies that reach 80%. Thus, a dual configuration of them is capable of covering up to 39 LTE (4G) bands besides the existing 2G and 3G bands. 2×2 MIMO configurations have been also developed for the two wideband antennas with a maximum isolation and a minimum correlation coefficient between the primary and the diversity antennas.

  13. Novel Wideband MIMO Antennas That Can Cover the Whole LTE Spectrum in Handsets and Portable Computers

    Directory of Open Access Journals (Sweden)

    Mohamed Sanad

    2014-01-01

    Full Text Available A dual resonant antenna configuration is developed for multistandard multifunction mobile handsets and portable computers. Only two wideband resonant antennas can cover most of the LTE spectrums in portable communication equipment. The bandwidth that can be covered by each antenna exceeds 70% without using any matching or tuning circuits, with efficiencies that reach 80%. Thus, a dual configuration of them is capable of covering up to 39 LTE (4G bands besides the existing 2G and 3G bands. 2×2 MIMO configurations have been also developed for the two wideband antennas with a maximum isolation and a minimum correlation coefficient between the primary and the diversity antennas.

  14. Wideband microwave generation with GaAs photoconductive switches

    Science.gov (United States)

    Druce, R. L.; Pocha, M. D.; Griffin, K. L.; Stein, J. M.; Obannon, B. J. J.

    1991-07-01

    We are using solid state photoconductive switches to generate wideband microwave pulses with peak powers to 20 MW. A parallel-plate Blumlein transmission line is used to directly feed an exponential taper antenna to produce single pulses with rise times of 200 ps and pulse durations of 340 ps (FWHM). Voltages up to 21 kV have been generated in a 1 cm tall, 12 cm wide parallel-plate line. With the switches operated in linear mode, we have demonstrated phasing of several switches to generate a coherent wave. Generated and radiated signals agree very well with numerical calculations. Radiation efficiencies approach 30 percent. The Blumlein dielectric can be changed to produce a damped waveform, thereby modifying the bandwidth of the signal. We have generated damped waveforms of up to 3 cycles using this method. The parallel-plate geometry lends itself to coupling to an antenna structure to radiate efficiently. The geometry also lends itself to expanding the generator in height and width. We have stacked two generators to nearly double the output power without degrading the pulse characteristics. Applications of ultrashort microwave pulses require a high repetition rate and long life from the generator. Life times of greater than 10(exp 5) shots have been seen occasionally at low to medium power densities. As the power density of a solid state photoconductive switch is increased, device life decreases. We have the capability to test devices at a repetition rate of 30 Hz and voltages to 25 kV. Preliminary data indicates that repeated pulse biasing (without switching) of large LEC grown devices in a slab geometry with fields as low as 30 kV/cm damages the switch and eventually leads to failure.

  15. Wideband microwave generation with GaAs photoconductive switches

    Energy Technology Data Exchange (ETDEWEB)

    Druce, R.L.; Pocha, M.D.; Griffin, K.L. (Lawrence Livermore National Lab., CA (United States)); Stein, J.M. (Rockwell International Corp., Albuquerque, NM (United States)); O' Bannon, B.J.J. (Rockwell International Corp., Anaheim, CA (United States))

    1991-01-01

    We are using solid state photoconductive switches to generate wideband microwave pulses with peak powers to 20 MW. A parallel-plate Blumlein transmission line is used to directly feed an exponential taper antenna to produce single pulses with rise times of 200 ps and pulse durations of 340 ps (FWHM). Voltages up to 21 kV have been generated in a 1 cm tall, 12 cm wide parallel-plate line. With the switches operated in linear mode, we have demonstrated phasing of several switches to generate a coherent wave. Generated and radiated signals agree very well with numerical calculations. Radiation efficiencies approach 30%. The Blumlein dielectric can be changed to produce a damped waveform, thereby modifying the bandwidth of the signal. We have generated damped waveforms of up to 3 cycles using this method. The parallel-plate geometry lends itself to coupling to an antenna structure to radiate efficiently. The geometry also lends itself to expanding the generator in height and width. We have stacked two generators to nearly double the output power without degrading the pulse characteristics. Applications of ultrashort microwave pulses (UWB radar, HPM weapons) require a high repetition rate and long life from the generator. Life times of >10{sup 5} shots have been seen occasionally at low to medium power densities. As the power density of a solid state photoconductive switch is increased, device life decreases. We have the capability to test devices at a repetition rate of 30 Hz and voltages to 25 kV. Preliminary data indicates that repeated pulse biasing (without switching) of large LEC grown devices in a slab geometry with fields as low as 30 kV/cm damages the switch and eventually leads to failure. 6 refs., 10 figs.

  16. Wideband perfect coherent absorber based on white-light cavity

    Science.gov (United States)

    Kotlicki, Omer; Scheuer, Jacob

    2015-03-01

    Coherent Perfect Absorbers (CPAs) are optical cavities which can be described as time-reversed lasers where light waves that enter the cavity, coherently interfere and react with the intra-cavity losses to yield perfect absorption. In contrast to lasers, which benefit from high coherency and narrow spectral linewidths, for absorbers these properties are often undesirable as absorption at a single frequency is highly susceptible to spectral noise and inappropriate for most practical applications. Recently, a new class of cavities, characterized by a spectrally wide resonance has been proposed. Such resonators, often referred to as White Light Cavities (WLCs), include an intra-cavity superluminal phase element, designed to provide a phase response with a slope that is opposite in sign and equal in magnitude to that of light propagation through the empty cavity. Consequently, the resonance phase condition in WLCs is satisfied over a band of frequencies providing a spectrally wide resonance. WLCs have drawn much attention due to their attractiveness for various applications such as ultra-sensitive sensors and optical buffering components. Nevertheless, WLCs exhibit inherent losses that are often undesirable. Here we introduce a simple wideband CPA device that is based on the WLC concept along with a complete analytical analysis. We present analytical and FDTD simulations of a practical, highly compact (12µm), Silicon based WLC-CPA that exhibits a flat and wide absorption profile (40nm) and demonstrate its usefulness as an optical pulse terminator (>35db isolation) and an all optical modulator that span the entire C-Band and exhibit high immunity to spectral noise.

  17. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development

    Science.gov (United States)

    Gardner, Jonathan (Technical Monitor); Tolls, Volker

    2004-01-01

    The optical modulation spectrometer (OMS) is a novel, highly efficient, low mass backend for heterodyne receiver systems. Current and future heterodyne receiver systems operating at frequencies up to a few THz require broadband spectrometer backends to achieve spectral resolutions of R approximately 10(exp 5) to 10(exp 6) to carry out many important astronomical investigations. Among these are observations of broad emission and absorption lines from extra-galactic objects at high redshifts, spectral line surveys, and observations of planetary atmospheres. Many of these lines are pressure or velocity broadened with either large half-widths or line wings extending over several GHz. Current backend systems can cover the needed bandwidth only by combining the output of several spectrometers, each with typically up to 1 GHz bandwidth, or by combining several frequency-shifted spectra taken with a single spectrometer. An ultra-wideband optical modulation spectrometer with 10 - 40 GHz bandwidth will enable broadband ob- servations without the limitations and disadvantages of hybrid spectrometers. Spectrometers like the OMS will be important for both ground-based observatories and future space missions like the Single Aperture Far-Infrared Telescope (SAFIR) which might carry IR/submm array heterodyne receiver systems requiring a spectrometer for each array pixel. Small size, low mass and small power consumption are extremely important for space missions. This report summarizes the specifications developed for the OMS and lists already identified commercial parts. The report starts with a review of the principle of operation, then describes the most important components and their specifications which were derived from theory, and finishes with a conclusion and outlook.

  18. Finiteness effects in wideband connected arrays: Analytical models to highlight the effects of the loading impedances

    NARCIS (Netherlands)

    Neto, A.; Cavallo, D.; Gerini, G.

    2011-01-01

    Most phased arrays are designed using infinite array theory, which does not account for edge effects. However, this approximation might not be adequate for the design of wideband arrays, for which truncation effects are more significant than in traditional narrow-band arrays. In particular, edge

  19. Design of an ultra-wideband ground-penetrating radar system using impulse radiating antennas

    NARCIS (Netherlands)

    Rhebergen, J.B.; Zwamborn, A.P.M.; Giri, D.V.

    1998-01-01

    At TNO-FEL, one of the research programs is to explore the use of ultra-wideband (UWB) electromagnetic fields in a bi-static ground-penetrating radar (GPR) system for the detection, location and identification of buried items of unexploded ordnance (e.g. land mines). In the present paper we describe

  20. Design of an ultra-wideband ground-penetrating radar system using impulse radiating antennas

    NARCIS (Netherlands)

    Rhebergen, J.B.; Zwamborn, A.P.M.; Giri, D.V.

    1999-01-01

    At TNO-FEL, one of the research programs is to explore the use of ultra-wideband (UWB) electromagnetic fields in a bi-static ground-penetrating radar (GPR) system for the detection, location and identification of buried items of unexploded ordnance (e.g. land mines). In the present paper we describe

  1. Iterative equalization for OFDM systems over wideband Multi-Scale Multi-Lag channels

    NARCIS (Netherlands)

    Xu, T.; Tang, Z.; Remis, R.; Leus, G.

    2012-01-01

    OFDM suffers from inter-carrier interference (ICI) when the channel is time varying. This article seeks to quantify the amount of interference resulting from wideband OFDM channels, which are assumed to follow the multi-scale multi-lag (MSML) model. The MSML channel model results in full channel

  2. Paper-based inkjet-printed ultra-wideband fractal antennas

    KAUST Repository

    Maza, Armando Rodriguez; Cook, Benjamin Stassen; Jabbour, Ghassan E.; Shamim, Atif

    2012-01-01

    For the first time, paper-based inkjet-printed ultra-wideband (UWB) fractal antennas are presented. Two new designs, a miniaturised UWB monopole, which utilises a fractal matching network and is the smallest reported inkjet-printed UWB printed

  3. Noise-based frequency offset modulation in wideband frequency-selective fading channels

    NARCIS (Netherlands)

    Meijerink, Arjan; Cotton, S.L.; Bentum, Marinus Jan; Scanlon, W.G.

    2009-01-01

    A frequency offset modulation scheme using wideband noise carriers is considered. The main advantage of such a scheme is that it enables fast receiver synchronization without channel adaptation, while providing robustness to multipath fading and in-band interference. This is important for low-power

  4. Study of plasma-based stable and ultra-wideband electromagnetic wave absorption for stealth application

    Science.gov (United States)

    Xuyang, CHEN; Fangfang, SHEN; Yanming, LIU; Wei, AI; Xiaoping, LI

    2018-06-01

    A plasma-based stable, ultra-wideband electromagnetic (EM) wave absorber structure is studied in this paper for stealth applications. The stability is maintained by a multi-layer structure with several plasma layers and dielectric layers distributed alternately. The plasma in each plasma layer is designed to be uniform, whereas it has a discrete nonuniform distribution from the overall view of the structure. The nonuniform distribution of the plasma is the key to obtaining ultra-wideband wave absorption. A discrete Epstein distribution model is put forward to constrain the nonuniform electron density of the plasma layers, by which the wave absorption range is extended to the ultra-wideband. Then, the scattering matrix method (SMM) is employed to analyze the electromagnetic reflection and absorption of the absorber structure. In the simulation, the validation of the proposed structure and model in ultra-wideband EM wave absorption is first illustrated by comparing the nonuniform plasma model with the uniform case. Then, the influence of various parameters on the EM wave reflection of the plasma are simulated and analyzed in detail, verifying the EM wave absorption performance of the absorber. The proposed structure and model are expected to be superior in some realistic applications, such as supersonic aircraft.

  5. Enhanced bit rate-distance product impulse radio ultra-wideband over fiber link

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Jensen, Jesper Bevensee; Caballero Jambrina, Antonio

    2010-01-01

    We report on a record distance and bit rate-wireless impulse radio (IR) ultra-wideband (UWB) link with combined transmission over a 20 km long fiber link. We are able to improve the compliance with the regulated frequency emission mask and achieve bit rate-distance products as high as 16 Gbit/s·m....

  6. Range extension and channel capacity increase in impulse-radio ultra-wideband communications

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Yu, Xianbin; Caballero Jambrina, Antonio

    2010-01-01

    We theoretically analyze the channel capacity of a 5th-order Gaussian pulse-based ultra-wideband (UWB) system and experimentally demonstrate 2 Gbit/s UWB-over-fiber transmission systems incorporating wireless transmission. Both electrical and photonic UWB pulse generation methods are employed...

  7. Wideband impedance measurements and modeling of DC motors for EMI predictions

    NARCIS (Netherlands)

    Diouf, F.; Leferink, Frank Bernardus Johannes; Duval, Fabrice; Bensetti, Mohamed

    2015-01-01

    In electromagnetic interference prediction, dc motors are usually modeled as a source and a series impedance. Previous researches only include the impedance of the armature, while neglecting the effect of the motor's rotation. This paper aims at measuring and modeling the wideband impedance of a dc

  8. A wideband high-linearity RF receiver front-end in CMOS

    NARCIS (Netherlands)

    Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

    This paper presents a wideband high-linearity RF receiver-front-end, implemented in standard 0.18 μm CMOS technology. The design employs a noise-canceling LNA in combination with two passive mixers, followed by lowpass-filtering and amplification at IF. The achieved bandwidth is >2 GHz, with a noise

  9. Wide-band CMOS low-noise amplifier exploiting thermal noise canceling

    NARCIS (Netherlands)

    Bruccoleri, F.; Klumperink, Eric A.M.; Nauta, Bram

    Known elementary wide-band amplifiers suffer from a fundamental tradeoff between noise figure (NF) and source impedance matching, which limits the NF to values typically above 3 dB. Global negative feedback can be used to break this tradeoff, however, at the price of potential instability. In

  10. Wideband CMOS receivers exploiting simultaneous output balancing and noise/distortion canceling

    NARCIS (Netherlands)

    Blaakmeer, S.C.; Klumperink, Eric A.M.; Leenaerts, D.M.W.; Nauta, Bram

    2008-01-01

    Abstract— This paper deals with the problem of realizing wideband receiver front-ends in downscaled CMOSTechnologies, which are highly wanted for multi-standard radio receivers and cognitive radio applications. Instead of using many narrowband inductor based receivers, we prefer the use of one

  11. Compact Wideband and Low-Profile Antenna Mountable on Large Metallic Surfaces

    DEFF Research Database (Denmark)

    Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    This paper proposes a compact wideband and low-profile antenna mountable on large metallic surfaces. Six rows of coupled microstrip resonators with different lengths are printed on a Teflon block. The lengths of the microstrip resonators in different rows are gradually reduced along the end-fire...

  12. Wideband two-port beam splitter of a binary fused-silica phase grating.

    Science.gov (United States)

    Wang, Bo; Zhou, Changhe; Feng, Jijun; Ru, Huayi; Zheng, Jiangjun

    2008-08-01

    The usual beam splitter of multilayer-coated film with a wideband spectrum is not easy to achieve. We describe the realization of a wideband transmission two-port beam splitter based on a binary fused-silica phase grating. To achieve high efficiency and equality in the diffracted 0th and -1st orders, the grating profile parameters are optimized using rigorous coupled-wave analysis at a wavelength of 1550 nm. Holographic recording and the inductively coupled plasma dry etching technique are used to fabricate the fused-silica beam splitter grating. The measured efficiency of (45% x 2) = 90% diffracted into the both orders can be obtained with the fabricated grating under Littrow mounting. The physical mechanism of such a wideband two-port beam splitter grating can be well explained by the modal method based on two-beam interference of the modes excited by the incident wave. With the high damage threshold, low coefficient of thermal expansion, and wideband high efficiency, the presented beam splitter etched in fused silica should be a useful optical element for a variety of practical applications.

  13. Wide-band residual phase-noise measurements on 40-GHz monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Hvam, Jørn Märcher

    2005-01-01

    We have performed wide-band residual phase-noise measurements on semiconductor 40-GHz mode-locked lasers by employing electrical waveguide components for the radio-frequency circuit. The intrinsic timing jitters of lasers with one, two, and three quantum wells (QW) are compared and our design......-QW laser. There is good agreement between the measured results and existing theory....

  14. First Experimental Impulse-Radio Ultra-Wideband Transmission Under the Russian Spectral Emission Mask

    DEFF Research Database (Denmark)

    Grakhova, Elizaveta P.; Rommel, Simon; Jurado-Navas, Antonio

    2016-01-01

    Ultra-wideband impulse-radio wireless transmission under the stringent conditions and complex shape of the Russian spectral emission mask is experimentally demonstrated for the first time. Transmission of 1Gbit/s and 1.25Gbit/s signals over distances of 6m and 3m is achieved with a BER below 3.8×10-3....

  15. Effect of Substrate Permittivity and Thickness on Performance of Single-Layer, Wideband, U-Slot Antennas on Microwave Substrates

    National Research Council Canada - National Science Library

    Natarajan, V; Chatterjee, D

    2004-01-01

    This paper presents effects of substrate permittivity and thickness on the performance characteristics like impedance bandwidth, radiation efficiency and gain of a single-layer, wideband, U-slot antenna...

  16. A numerical study of super-resolution through fast 3D wideband algorithm for scattering in highly-heterogeneous media

    KAUST Repository

    Lé tourneau, Pierre-David; Wu, Ying; Papanicolaou, George; Garnier, Josselin; Darve, Eric

    2016-01-01

    We present a wideband fast algorithm capable of accurately computing the full numerical solution of the problem of acoustic scattering of waves by multiple finite-sized bodies such as spherical scatterers in three dimensions. By full solution, we

  17. Spectral encoded optical label detection for dynamic routing of impulse radio ultra-wideband signals in metro-access networks

    DEFF Research Database (Denmark)

    Osadchiy, Alexey Vladimirovich; Yu, Xianbin; Yin, Xiaoli

    2010-01-01

    In this paper we propose and experimentally demonstrate the principle of coherent label detection for dynamic routing of wavelength division multiplexed impulse radio ultra-wideband signals by using four-tone spectral amplitude coded labels.......In this paper we propose and experimentally demonstrate the principle of coherent label detection for dynamic routing of wavelength division multiplexed impulse radio ultra-wideband signals by using four-tone spectral amplitude coded labels....

  18. High Performance Wideband CMOS CCI and its Application in Inductance Simulator Design

    Directory of Open Access Journals (Sweden)

    ARSLAN, E.

    2012-08-01

    Full Text Available In this paper, a new, differential pair based, low-voltage, high performance and wideband CMOS first generation current conveyor (CCI is proposed. The proposed CCI has high voltage swings on ports X and Y and very low equivalent impedance on port X due to super source follower configuration. It also has high voltage swings (close to supply voltages on input and output ports and wideband current and voltage transfer ratios. Furthermore, two novel grounded inductance simulator circuits are proposed as application examples. Using HSpice, it is shown that the simulation results of the proposed CCI and also of the presented inductance simulators are in very good agreement with the expected ones.

  19. Inkjet Printing of Paper-Based Wideband and High Gain Antennas

    KAUST Repository

    Cook, Benjamin

    2011-12-07

    This thesis represents a major contribution to wideband and high gain inkjet-printed antennas on paper. This work includes the complete characterization of the inkjet printing process for passive microwave devices on paper substrate as well as several ultra-wideband and high gain antenna designs. The characterization work includes the electrical characterization of the permittivity and loss tangent for paper substrate through 10 GHz, ink conductivity data for variable sintering conditions, and minimum feature sizes obtainable by today’s current inkjet processes for metallic nanoparticles. For the first time ever, inkjet-printed antennas are demonstrated that operate over the entire UWB band and demonstrate gains up to 8dB. This work also presents the first fractal-based inkjet-printed antennas with enhanced bandwidth and reduced production costs, and a novel slow wave log periodic dipole array which shows minimizations of 20% in width over conventional log periodic antennas.

  20. Generation of flat wideband chaos with suppressed time delay signature by using optical time lens.

    Science.gov (United States)

    Jiang, Ning; Wang, Chao; Xue, Chenpeng; Li, Guilan; Lin, Shuqing; Qiu, Kun

    2017-06-26

    We propose a flat wideband chaos generation scheme that shows excellent time delay signature suppression effect, by injecting the chaotic output of general external cavity semiconductor laser into an optical time lens module composed of a phase modulator and two dispersive units. The numerical results demonstrate that by properly setting the parameters of the driving signal of phase modulator and the accumulated dispersion of dispersive units, the relaxation oscillation in chaos can be eliminated, wideband chaos generation with an efficient bandwidth up to several tens of GHz can be achieved, and the RF spectrum of generated chaotic signal is nearly as flat as uniform distribution. Moreover, the periodicity of chaos induced by the external cavity modes can be simultaneously destructed by the optical time lens module, based on this the time delay signature can be completely suppressed.

  1. The Large Office Environment - Measurement and Modeling of the Wideband Radio Channel

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Nielsen, Jesper Ødum; Bauch, Gerhard

    2006-01-01

    In a future 4G or WLAN wideband application we can imagine multiple users in a large office environment con-sisting of a single room with partitions. Up to now, indoor radio channel measurement and modelling has mainly concentrated on scenarios with several office rooms and corridors. We present...... here measurements at 5.8GHz for 100 MHz bandwidth and a novel modelling approach for the wideband radio channel in a large office room envi-ronment. An acoustic like reverberation theory is pro-posed that allows to specify a tapped delay line model just from the room dimensions and an average...... calculated from the measurements. The pro-posed model can likely also be applied to indoor hot spot scenarios....

  2. Coding/modulation trade-offs for Shuttle wideband data links

    Science.gov (United States)

    Batson, B. H.; Huth, G. K.; Trumpis, B. D.

    1974-01-01

    This paper describes various modulation and coding schemes which are potentially applicable to the Shuttle wideband data relay communications link. This link will be capable of accommodating up to 50 Mbps of scientific data and will be subject to a power constraint which forces the use of channel coding. Although convolutionally encoded coherent binary PSK is the tentative signal design choice for the wideband data relay link, FM techniques are of interest because of the associated hardware simplicity and because an FM system is already planned to be available for transmission of television via relay satellite to the ground. Binary and M-ary FSK are considered as candidate modulation techniques, and both coherent and noncoherent ground station detection schemes are examined. The potential use of convolutional coding is considered in conjunction with each of the candidate modulation techniques.

  3. 35 Gb/s Ultra-wideband Technology for Advanced Communications

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    be applied, evolving from classic spectral inefficient pulsebased systems to more advanced and flexible modulation schemes. Ultra-wideband technology is suitable for low-power high-speed wireless communication systems over short distances, and is an appealing alternative for next generation networks ranging......The fast development of electronics and portable devices, intended mainly for multimedia applications, is increasing exponentially the data traffic demands per user. To cope with these new data demands in limited bandwidth systems, new technologies must be explored and new transmission schemes must...... from high-speed wireless personal area networks, to the internet of things applications. Its popularity stems from the fact that they can be used as an overlay to existing systems, without interference, operating in parallel to existing wireless systems, which perceive ultra-wideband emissions...

  4. Micro-Doppler Ambiguity Resolution for Wideband Terahertz Radar Using Intra-Pulse Interference.

    Science.gov (United States)

    Yang, Qi; Qin, Yuliang; Deng, Bin; Wang, Hongqiang; You, Peng

    2017-04-29

    Micro-Doppler, induced by micro-motion of targets, is an important characteristic of target recognition once extracted via parameter estimation methods. However, micro-Doppler is usually too significant to result in ambiguity in the terahertz band because of its relatively high carrier frequency. Thus, a micro-Doppler ambiguity resolution method for wideband terahertz radar using intra-pulse interference is proposed in this paper. The micro-Doppler can be reduced several dozen times its true value to avoid ambiguity through intra-pulse interference processing. The effectiveness of this method is proved by experiments based on a 0.22 THz wideband radar system, and its high estimation precision and excellent noise immunity are verified by Monte Carlo simulation.

  5. Multiband and wideband monopole antenna for GSM900 and other wireless applications

    KAUST Repository

    Abutarboush, Hattan; Nasif, H.; Nilavalan, Rajagopal; Cheung, Sing Wai

    2012-01-01

    In this letter, the design of a compact monopole antenna for multiband and wideband operations is proposed. The antenna has three distinct frequency bands, centered at 0.94, 2.7, and 4.75 GHz. The antenna has a compact size of only 30×40×1.57 mm$ 3 including the ground plane. The multiband and wideband operations are achieved by using an E-shaped slot on the ground plane. The design procedure is also discussed. The frequency bands can be independently controlled by using the parameters of the E-slot. The impedance bandwidth, current distributions, radiation patterns, gain, and efficiency of the antenna are studied by computer simulation and measurements. © 2011 IEEE.

  6. 10th and 11th conference on Ultra-Wideband Short-Pulse Electromagnetics

    CERN Document Server

    Mokole, Eric; UWB SP 10; UWB SP 11

    2014-01-01

    This book presents contributions of deep technical content and high scientific quality in the areas of electromagnetic theory, scattering, UWB antennas, UWB systems, ground penetrating radar (GPR), UWB communications, pulsed-power generation, time-domain computational electromagnetics, UWB compatibility, target detection and discrimination, propagation through dispersive media, and wavelet and multi-resolution techniques. Ultra-wideband (UWB), short-pulse (SP) electromagnetics are now being used for an increasingly wide variety of applications, including collision avoidance radar, concealed object detection, and communications. Notable progress in UWB and SP technologies has been achieved by investigations of their theoretical bases and improvements in solid-state manufacturing, computers, and digitizers. UWB radar systems are also being used for mine clearing, oil pipeline inspections, archeology, geology, and electronic effects testing. Like previous books in this series, Ultra-Wideband Short-Pulse Electrom...

  7. Spatial Dynamic Wideband Modeling of the MIMO Satellite-to-Earth Channel

    Directory of Open Access Journals (Sweden)

    Andreas Lehner

    2014-01-01

    response (CIR time series depending on the movement profile of a land mobile terminal is presented in this paper. Based on high precise wideband measurements in L-band the model reproduces the correlated shadowing and multipath conditions in rich detail. The model includes time and space variant echo signals appearing and disappearing in dependence on the receive antenna position and movement, and the actual azimuths and elevations to the various signal sources. Attenuation and path delays relative to the hypothetical line of sight (LOS ensure usability for ranging purposes. Parameters for car and pedestrian applications in urban and suburban environments are provided. The channel characteristics are determined independently of the transmitted signal. Therefore the usability, for example, for GPS and GALILEO, as well as wideband communication services from hovering platforms, is given.

  8. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya [College of Science, Air Force Engineering University, Xi' an, Shaanxi 710051 (China); Zhang, Jieqiu [College of Science, Air Force Engineering University, Xi' an, Shaanxi 710051 (China); Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xu, Zhuo [Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Zhang, Anxue [School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2014-06-02

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  9. Ultra-wideband wireless receiver front-end for high-speed indoor applications

    Directory of Open Access Journals (Sweden)

    Zhe-Yang Huang

    2014-12-01

    Full Text Available Low-noise, ultra-wideband (UWB wireless receiver front-end circuits were presented in this study. A two-stage common-source low-noise amplifier with wideband input impedance matching network, an active-balun and a double-balanced down-conversion mixer were adopted in the UWB wireless receiver front-end. The proposed wireless receiver front-end circuits were implemented in 0.18 μm radio-frequency-CMOS process. The maximum down-conversion power gain of the front-end is 25.8 dB; minimum single-sideband noise figure of the front-end is 4.9 dB over complete UWB band ranging from 3.1 to 10.6 GHz. Power consumption including buffers is 39.2 mW.

  10. Comparison of fundamental and wideband harmonic contrast imaging of liver tumors.

    Science.gov (United States)

    Forsberg, F; Liu, J B; Chiou, H J; Rawool, N M; Parker, L; Goldberg, B B

    2000-03-01

    Wideband harmonic imaging (with phase inversion for improved tissue suppression) was compared to fundamental imaging in vivo. Four woodchucks with naturally occurring liver tumors were injected with Imagent (Alliance Pharmaceutical Corp., San Diego, CA). Randomized combinations of dose (0.05, 0.2 and 0.4 ml/kg) and acoustic output power (AO; 5, 25 and 63% or MI Siemens Medical Systems, Issaquah, WA). Tumor vascularity, conspicuity and contrast enhancement were rated by three independent observers. Imagent produced marked tumor enhancement and improved depiction of neovascularity at all dosages and AO settings in both modes. Tumor vascularity and enhancement correlated with mode, dose and AO (P < 0.002). Fundamental imaging produced more enhancement (P < 0.05), but tumor vascularity and conspicuity were best appreciated in harmonic mode (P < 0.05). Under the conditions studied here, the best approach was wideband harmonic imaging with 0.2 ml/kg of Imagent at an AO of 25%.

  11. 7th conference on ultra-wideband, short-pulse electromagnetics

    CERN Document Server

    Schenk, Uwe; Nitsch, Daniel; Sabath, Frank; Ultra-Wideband, Short-Pulse Electromagnetics 7; UWBSP7

    2007-01-01

    Ultra-wideband (UWB), short-pulse (SP) electromagnetics are now being used for an increasingly wide variety of applications, including collision avoidance radar, concealed object detection, and communications. Notable progress in UWB and SP technologies has been achieved by investigations of their theoretical bases and improvements in solid-state manufacturing, computers, and digitizers. UWB radar systems are also being used for mine clearing, oil pipeline inspections, archeology, geology, and electronic effects testing. Ultra-Wideband Short-Pulse Electromagnetics 7 presents selected papers of deep technical content and high scientific quality from the UWB-SP7 Conference, including wide-ranging contributions on electromagnetic theory, scattering, UWB antennas, UWB systems, ground penetrating radar (GPR), UWB communications, pulsed-power generation, time-domain computational electromagnetics, UWB compatibility, target detection and discrimination, propagation through dispersive media, and wavelet and multi-res...

  12. A low-noise, wideband, integrated CMOS transimpedance preamplifier for photodiode applications

    International Nuclear Information System (INIS)

    Binkley, D.M.; Paulus, M.J.; Casey, M.E.; Rochelle, J.M.

    1992-01-01

    In this paper, a low-noise, wideband, integrated CMOS transimpedance preamplifier is presented for silicon avalanche photodiode (APD) applications. The preamplifier, fabricated in a standard 2μ CMOS technology, features a transimpedance gain of 45 kΩ, a risetime of 22 ns, a series noise of 1.6nV/Hz 1/2 , and a wideband equivalent input-noise current of 12 nA for a source capacitance of 12 pF. The measured 22 Na timing resolution of 9.2-ns FWHM and energy resolution of 22.4% FWHM for the RCA C30994 BGO/APD detector module coupled to the preamplifier is comparable to the performance reported using charge-sensitive preamplifiers. This illustrates that transimpedance preamplifiers should be considered for APD applications, especially where APD noise current dominates noise from feedback resistors in the 1--kΩ to 50-kΩ range

  13. Design of a Compact Wideband Antenna Array for Microwave Imaging Applications

    Directory of Open Access Journals (Sweden)

    J. Puskely

    2013-12-01

    Full Text Available In the paper, wideband antenna arrays aimed at microwave imaging applications and SAR applications operating at Ka band were designed. The antenna array feeding network is realized by a low-loss SIW technology. Moreover, we have replaced the large feed network comprised of various T and Y junctions by a simple broadband network of compact size to more reduce losses in the substrate integrated waveguide and also save space on the PCB. The designed power 8-way divider is complemented by a wideband substrate integrated waveguide to a grounded coplanar waveguide transition and directly connected to the antenna elements. The measured results of antenna array are consistent with our simulation. Obtained results of the developed array demonstrated improvement compared to previously developed binary feed networks with microstrip or SIW splitters.

  14. Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide

    DEFF Research Database (Denmark)

    Xiao, Binggang; Li, Sheng-Hua; Xiao, Sanshui

    2016-01-01

    Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide is proposed. Owing to subwavelength confinement, such a filter has advantage in the structure size without sacrificing the performance. The spoof SPP based notch is introduced to suppress the WLAN and satel...... and satellite communication signals. Due to planar structures proposed here, it is easy to integrate in the microwave integrated systems, which can play an important role in the microwave communication circuit and system.......Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide is proposed. Owing to subwavelength confinement, such a filter has advantage in the structure size without sacrificing the performance. The spoof SPP based notch is introduced to suppress the WLAN...

  15. Dual-polarization, wideband microstrip antenna array for airborne C-band SAR

    DEFF Research Database (Denmark)

    Granholm, Johan; Skou, Niels

    2000-01-01

    The paper describes the development of a C-band, dual linear polarization wideband antenna array, for use in the next-generation of the Danish airborne polarimetric synthetic aperture radar (SAR) system. The array is made of probe-fed, stacked microstrip patches. The design and performance of the...... of the basic stacked patch element, operating from 4.9 GHz to 5.7 GHz, and a 2×2 element test array of these, are described.......The paper describes the development of a C-band, dual linear polarization wideband antenna array, for use in the next-generation of the Danish airborne polarimetric synthetic aperture radar (SAR) system. The array is made of probe-fed, stacked microstrip patches. The design and performance...

  16. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    International Nuclear Information System (INIS)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya; Zhang, Jieqiu; Xu, Zhuo; Zhang, Anxue

    2014-01-01

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  17. Effects of Compound K-Distributed Sea Clutter on Angle Measurement of Wideband Monopulse Radar

    Directory of Open Access Journals (Sweden)

    Hong Zhu

    2017-01-01

    Full Text Available The effects of compound K-distributed sea clutter on angle measurement of wideband monopulse radar are investigated in this paper. We apply the conditional probability density function (pdf of monopulse ratio (MR error to analyze these effects. Based on the angle measurement procedure of the wideband monopulse radar, this conditional pdf is first deduced in detail for the case of compound K-distributed sea clutter plus noise. Herein, the spatial correlation of the texture components for each channel clutter and the correlation of the texture components between the sum and difference channel clutters are considered, and two extreme situations for each of them are tackled. Referring to the measured sea clutter data, angle measurement performances in various K-distributed sea clutter plus noise circumstances are simulated, and the effects of compound K-distributed sea clutter on angle measurement are discussed.

  18. Wideband laser locking to an atomic reference with modulation transfer spectroscopy.

    Science.gov (United States)

    Negnevitsky, V; Turner, L D

    2013-02-11

    We demonstrate that conventional modulated spectroscopy apparatus, used for laser frequency stabilization in many atomic physics laboratories, can be enhanced to provide a wideband lock delivering deep suppression of frequency noise across the acoustic range. Using an acousto-optic modulator driven with an agile oscillator, we show that wideband frequency modulation of the pump laser in modulation transfer spectroscopy produces the unique single lock-point spectrum previously demonstrated with electro-optic phase modulation. We achieve a laser lock with 100 kHz feedback bandwidth, limited by our laser control electronics. This bandwidth is sufficient to reduce frequency noise by 30 dB across the acoustic range and narrows the imputed linewidth by a factor of five.

  19. Distributed fiber sparse-wideband vibration sensing by sub-Nyquist additive random sampling

    Science.gov (United States)

    Zhang, Jingdong; Zheng, Hua; Zhu, Tao; Yin, Guolu; Liu, Min; Bai, Yongzhong; Qu, Dingrong; Qiu, Feng; Huang, Xianbing

    2018-05-01

    The round trip time of the light pulse limits the maximum detectable vibration frequency response range of phase-sensitive optical time domain reflectometry ({\\phi}-OTDR). Unlike the uniform laser pulse interval in conventional {\\phi}-OTDR, we randomly modulate the pulse interval, so that an equivalent sub-Nyquist additive random sampling (sNARS) is realized for every sensing point of the long interrogation fiber. For an {\\phi}-OTDR system with 10 km sensing length, the sNARS method is optimized by theoretical analysis and Monte Carlo simulation, and the experimental results verify that a wide-band spars signal can be identified and reconstructed. Such a method can broaden the vibration frequency response range of {\\phi}-OTDR, which is of great significance in sparse-wideband-frequency vibration signal detection, such as rail track monitoring and metal defect detection.

  20. Spectrally-Precoded OFDM for 5G Wideband Operation in Fragmented sub-6GHz Spectrum

    OpenAIRE

    Pitaval, Renaud-Alexandre; Popović, Branislav M.; Mohamad, Medhat; Nilsson, Rickard; van de Beek, Jaap

    2016-01-01

    We consider spectrally-precoded OFDM waveforms for 5G wideband transmission in sub-6GHz band. In this densely packed spectrum, a low out-of-band (OOB) waveform is a critical 5G component to achieve the promised high spectral efficiency. By precoding data symbols before OFDM modulation, it is possible to achieve extremely low out-of-band emission with very sharp spectrum transition enabling an efficient and flexible usage of frequency resources. Spectrally-precoded OFDM shows promising results...

  1. High-speed ultra-wideband wireless signals over fiber systems: photonic generation and DSP detection

    DEFF Research Database (Denmark)

    Yu, Xianbin; Gibbon, Timothy Braidwood; Tafur Monroy, Idelfonso

    2009-01-01

    We firstly review the efforts in the literature on ultra-wideband (UWB)-over-fiber systems. Secondly, we present experimental results on photonic generation of high-speed UWB signals by both direct modulation and external optical injecting an uncooled semiconductor laser. Furthermore, we introduce...... the use of digital signal processing (DSP) technology to receive the generated UWB signal at 781.25 Mbit/s. Error-free transmission is achieved....

  2. Spatial Dynamic Wideband Modeling of the MIMO Satellite-to-Earth Channel

    OpenAIRE

    Lehner, Andreas; Steingass, Alexander

    2014-01-01

    A novel MIMO (multiple input multiple output) satellite channel model that allows the generation of associated channel impulse response (CIR) time series depending on the movement profile of a land mobile terminal is presented in this paper. Based on high precise wideband measurements in L-band the model reproduces the correlated shadowing and multipath conditions in rich detail. The model includes time and space variant echo signals appearing and disappearing in dependence on the receive ...

  3. A Wideband and Compact Circularly-Polarized Rectenna for Low Power Application

    OpenAIRE

    Okba , Abderrahim; Takacs , Alexandru; Aubert , Hervé; Bellion , Anthony; Grenana , D

    2017-01-01

    International audience; This paper presents a wideband and compact circularly polarized rectenna composed by an Archimedean spiral antenna that covers the S and C frequency bands and a silicon Schottky diode. This rectenna (rectifier + antenna) is used for electromagnetic energy harvesting over a wide frequency band, in order to power autonomous wireless sensors used for satellite health monitoring. For low incident power densities (around 14 µW/cm²) the measured efficiency of at least 19% be...

  4. Characterization of the bistable wideband optical filter on the basis of nonlinear 2D photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Guryev, I. V., E-mail: guryev@ieee.org; Sukhoivanov, I. A., E-mail: guryev@ieee.org; Andrade Lucio, J. A., E-mail: guryev@ieee.org; Manzano, O. Ibarra, E-mail: guryev@ieee.org; Rodriguez, E. Vargaz, E-mail: guryev@ieee.org; Gonzales, D. Claudio, E-mail: guryev@ieee.org; Chavez, R. I. Mata, E-mail: guryev@ieee.org; Gurieva, N. S., E-mail: guryev@ieee.org [University of Guanajuato, Engineering division (Mexico)

    2014-05-15

    In our work, we investigated the wideband optical filter on the basis of nonlinear photonic crystal. The all-optical flip-flop using ultra-short pulses with duration lower than 200 fs is obtained in such filters. Here we pay special attention to the stability problem of the nonlinear element. To investigate this problem, the temporal response demonstrating the flip-flop have been computed within the certain range of the wavelengths as well as at different input power.

  5. Wide-band CMOS low-noise amplifier exploiting thermal noise canceling

    OpenAIRE

    Bruccoleri, F.; Klumperink, Eric A.M.; Nauta, Bram

    2004-01-01

    Known elementary wide-band amplifiers suffer from a fundamental tradeoff between noise figure (NF) and source impedance matching, which limits the NF to values typically above 3 dB. Global negative feedback can be used to break this tradeoff, however, at the price of potential instability. In contrast, this paper presents a feedforward noise-canceling technique, which allows for simultaneous noise and impedance matching, while canceling the noise and distortion contributions of the matching d...

  6. Semi-blind identification of wideband MIMO channels via stochastic sampling

    OpenAIRE

    Andrieu, Christophe; Piechocki, Robert J.; McGeehan, Joe P.; Armour, Simon M.

    2003-01-01

    In this paper we address the problem of wide-band multiple-input multiple-output (MIMO) channel (multidimensional time invariant FIR filter) identification using Markov chains Monte Carlo methods. Towards this end we develop a novel stochastic sampling technique that produces a sequence of multidimensional channel samples. The method is semi-blind in the sense that it uses a very short training sequence. In such a framework the problem is no longer analytically tractable; hence we resort to s...

  7. Wideband Small-Signal Input dq Admittance Modeling of Six-Pulse Diode Rectifiers

    DEFF Research Database (Denmark)

    Yue, Xiaolong; Wang, Xiongfei; Blaabjerg, Frede

    2018-01-01

    This paper studies the wideband small-signal input dq admittance of six-pulse diode rectifiers. Considering the frequency coupling introduced by ripple frequency harmonics of d-and q-channel switching function, the proposed model successfully predicts the small-signal input dq admittance of six......-pulse diode rectifiers in high frequency regions that existing models fail to explain. Simulation and experimental results verify the accuracy of the proposed model....

  8. Ultra - Wideband, zero visual signature RF vest antenna for man-portable radios

    OpenAIRE

    Lebaric, Jovan E.; Adler, Richard W.; Limbert, Matthew E.

    2001-01-01

    This paper presents the recent research of the COMbat Wear INtegration (COMWIN) RF Vest antenna presented at MILCOM2000. This version of the ultra-wideband VHF/UHF (30 MHz to 500 MHz) vest antenna, designated as MK-III, is integrated into the existing dismounted Marine/Soldier Kevlar flak vest and has no visual signature. This antenna is one of the three COMWIN antennas developed at the Naval Postgraduate School (NPS) for the Joint Tactical Radio System applications. ...

  9. Age and Gender Effects on Wideband Absorbance in Adults with Normal Outer and Middle Ear Function

    Science.gov (United States)

    Mazlan, Rafidah; Kei, Joseph; Ya, Cheng Li; Yusof, Wan Nur Hanim Mohd; Saim, Lokman; Zhao, Fei

    2015-01-01

    Purpose: This study examined the effects of age and gender on wideband energy absorbance in adults with normal middle ear function. Method: Forty young adults (14 men, 26 women, aged 20-38 years), 31 middle-aged adults (16 men, 15 women, aged 42-64 years), and 30 older adults (20 men, 10 women, aged 65-82 years) were assessed. Energy absorbance…

  10. Maximum Likelihood DOA Estimation of Multiple Wideband Sources in the Presence of Nonuniform Sensor Noise

    Directory of Open Access Journals (Sweden)

    K. Yao

    2007-12-01

    Full Text Available We investigate the maximum likelihood (ML direction-of-arrival (DOA estimation of multiple wideband sources in the presence of unknown nonuniform sensor noise. New closed-form expression for the direction estimation Cramér-Rao-Bound (CRB has been derived. The performance of the conventional wideband uniform ML estimator under nonuniform noise has been studied. In order to mitigate the performance degradation caused by the nonuniformity of the noise, a new deterministic wideband nonuniform ML DOA estimator is derived and two associated processing algorithms are proposed. The first algorithm is based on an iterative procedure which stepwise concentrates the log-likelihood function with respect to the DOAs and the noise nuisance parameters, while the second is a noniterative algorithm that maximizes the derived approximately concentrated log-likelihood function. The performance of the proposed algorithms is tested through extensive computer simulations. Simulation results show the stepwise-concentrated ML algorithm (SC-ML requires only a few iterations to converge and both the SC-ML and the approximately-concentrated ML algorithm (AC-ML attain a solution close to the derived CRB at high signal-to-noise ratio.

  11. A wideband optical monitor for a planetary-rotation coating-system

    International Nuclear Information System (INIS)

    Campanelli, M.B.; Smith, D.J.

    1998-01-01

    A substrate-specific, through-planet, wideband optical coating monitor is being developed to increase production yield and the understanding of physical vapor deposition (PVD) coatings fabricated in the Optical Manufacturing Laboratory at the University of Rochester's Laboratory for Laser Energetics. In-situ wideband optical monitoring of planetary rotation systems allows direct monitoring of large, expensive substrates with complex layering schemes. The optical monitor discussed here is under development for coating several large (e.g., 80.7 x 41.7 x 9.0 cm) polarizers for the National Ignition Facility. Wideband optical monitoring of the production substrates is used in concert with an array of crystal monitors for process control, film parameter evaluation, and error detection with associated design reoptimization. The geometry of a planetary rotation system, which produces good uniformity across large substrates, makes optical monitoring more difficult. Triggering and timing techniques for data acquisition become key to the process because the optical coating is available only intermittently for monitoring. Failure to properly consider the effects of the system dynamics during data retrieval and processing may result in significant decreases in the spectral data's reliability. Improved data accuracy allows better determination of film thicknesses, indices, and inhomogeneities and enables in-situ error detection for design reoptimization

  12. Wideband excitation in nonlinear vibro-acoustic modulation for damage detection

    Science.gov (United States)

    Klepka, A.; Adamczyk, M.; Pieczonka, L.; Staszewski, W. J.

    2016-04-01

    The paper discusses the use of wideband excitation in nonlinear vibro-acoustic modulation technique (VAM) used for damage detection. In its original form, two mono-harmonic signals (low and high frequency) are used for excitation. The low frequency excitation is typically selected based on a modal analysis test and high frequency excitation is selected arbitrarily in the ultrasonic frequency range. This paper presents a different approach with use of wideband excitation signals. The proposed approach gives the possibility to simplify the testing procedure by omitting the modal test used to determine the value of low frequency excitation. Simultaneous use of wideband excitation for high frequency solves the ambiguity related to the selection of the frequency of acoustic wave. Broadband excitation signals require, however, more elaborate signal processing methods to determine the intensity of modulation for a given bandwidth. The paper discusses the proposed approach and the related signal processing procedure. Experimental validation of the proposed technique is performed on a laminated composite plate with a barely visible impact damage that was generated in an impact test. Piezoceramic actuators are used for vibration excitation and a scanning laser vibrometer is used for noncontact data acquisition.

  13. Robust Nearfield Wideband Beamforming Design Based on Adaptive-Weighted Convex Optimization

    Directory of Open Access Journals (Sweden)

    Guo Ye-Cai

    2017-01-01

    Full Text Available Nearfield wideband beamformers for microphone arrays have wide applications in multichannel speech enhancement. The nearfield wideband beamformer design based on convex optimization is one of the typical representatives of robust approaches. However, in this approach, the coefficient of convex optimization is a constant, which has not used all the freedom provided by the weighting coefficient efficiently. Therefore, it is still necessary to further improve the performance. To solve this problem, we developed a robust nearfield wideband beamformer design approach based on adaptive-weighted convex optimization. The proposed approach defines an adaptive-weighted function by the adaptive array signal processing theory and adjusts its value flexibly, which has improved the beamforming performance. During each process of the adaptive updating of the weighting function, the convex optimization problem can be formulated as a SOCP (Second-Order Cone Program problem, which could be solved efficiently using the well-established interior-point methods. This method is suitable for the case where the sound source is in the nearfield range, can work well in the presence of microphone mismatches, and is applicable to arbitrary array geometries. Several design examples are presented to verify the effectiveness of the proposed approach and the correctness of the theoretical analysis.

  14. Dynamics of Gradient Bioceramic Composite Coating on Surface of Titanium Alloy by Wide-Band Laser Cladding

    Institute of Scientific and Technical Information of China (English)

    LIU Qi-bin; ZOU Long-jiang; ZHU Wei-dong; LI Hai-tao; DONG Chuang

    2004-01-01

    The gradient bioceramic coating was prepared on the surface of titanium alloy using wide-band laser cladding. The dynamics of gradient bioceramic composite coating containing hydroxyapatite (HA) prepared with mixture of CaHPO4*2H2O and CaCO3 under the condition of wide-band laser was studied theoretically. The corresponding mathematical model and its numerical solution were presented. The examination experiment showed that HA bioceramic composite coatings can be obtained by appropriately choosing wide-band laser cladding parameters. The microstructure and surface morphology of HA bioceramic coating were observed by SEM and X-ray diffraction. The experimental results showed that the bioceramic coating is composed of HA, β-TCP, CaO, CaTiO3 and TiO2. The surface of bioceramic coating takes coral-shaped structure or short-rod piled structure, which helps osteoblast grow into bioceramic and improves the biocompatibility.

  15. Efficient Wideband Spectrum Sensing with Maximal Spectral Efficiency for LEO Mobile Satellite Systems

    Directory of Open Access Journals (Sweden)

    Feilong Li

    2017-01-01

    Full Text Available The usable satellite spectrum is becoming scarce due to static spectrum allocation policies. Cognitive radio approaches have already demonstrated their potential towards spectral efficiency for providing more spectrum access opportunities to secondary user (SU with sufficient protection to licensed primary user (PU. Hence, recent scientific literature has been focused on the tradeoff between spectrum reuse and PU protection within narrowband spectrum sensing (SS in terrestrial wireless sensing networks. However, those narrowband SS techniques investigated in the context of terrestrial CR may not be applicable for detecting wideband satellite signals. In this paper, we mainly investigate the problem of joint designing sensing time and hard fusion scheme to maximize SU spectral efficiency in the scenario of low earth orbit (LEO mobile satellite services based on wideband spectrum sensing. Compressed detection model is established to prove that there indeed exists one optimal sensing time achieving maximal spectral efficiency. Moreover, we propose novel wideband cooperative spectrum sensing (CSS framework where each SU reporting duration can be utilized for its following SU sensing. The sensing performance benefits from the novel CSS framework because the equivalent sensing time is extended by making full use of reporting slot. Furthermore, in respect of time-varying channel, the spatiotemporal CSS (ST-CSS is presented to attain space and time diversity gain simultaneously under hard decision fusion rule. Computer simulations show that the optimal sensing settings algorithm of joint optimization of sensing time, hard fusion rule and scheduling strategy achieves significant improvement in spectral efficiency. Additionally, the novel ST-CSS scheme performs much higher spectral efficiency than that of general CSS framework.

  16. Novel ultra-wideband photonic signal generation and transmission featuring digital signal processing bit error rate measurements

    DEFF Research Database (Denmark)

    Gibbon, Timothy Braidwood; Yu, Xianbin; Tafur Monroy, Idelfonso

    2009-01-01

    We propose the novel generation of photonic ultra-wideband signals using an uncooled DFB laser. For the first time we experimentally demonstrate bit-for-bit DSP BER measurements for transmission of a 781.25 Mbit/s photonic UWB signal.......We propose the novel generation of photonic ultra-wideband signals using an uncooled DFB laser. For the first time we experimentally demonstrate bit-for-bit DSP BER measurements for transmission of a 781.25 Mbit/s photonic UWB signal....

  17. A photonic ultra-wideband pulse generator based on relaxation oscillations of a semiconductor laser

    DEFF Research Database (Denmark)

    Yu, Xianbin; Gibbon, Timothy Braidwood; Pawlik, Michal

    2009-01-01

    A photonic ultra-wideband (UWB) pulse generator based on relaxation oscillations of a semiconductor laser is proposed and experimentally demonstrated. We numerically simulate the modulation response of a direct modulation laser (DML) and show that due to the relaxation oscillations of the laser......, the generated signals with complex shape in time domain match the Federal Communications Commission (FCC) mask in the frequency domain. Experimental results using a DML agree well with simulation predictions. Furthermore, we also experimentally demonstrate the generation of FCC compliant UWB signals...

  18. A high-speed Schottky detector for ultra-wideband communications

    DEFF Research Database (Denmark)

    Valdecasa, Guillermo Silva; Cimoli, Bruno; Blanco Granja, Ángel

    2017-01-01

    This letter reviews the design procedure of a high‐speed Schottky video detector for high‐data‐rate communications within the ultra‐wideband (UWB) frequencies. The classic design approach for video detectors is extended with a mixer‐like analysis, which results in a more detailed assessment of th....... Using 0 dBm carrier power, the lowest measured conversion loss is 10 dB for a video frequency of 1.1 GHz and better than 13 dB up to 1.8 GHz....

  19. Generation of wideband chaos with suppressed time-delay signature by delayed self-interference.

    Science.gov (United States)

    Wang, Anbang; Yang, Yibiao; Wang, Bingjie; Zhang, Beibei; Li, Lei; Wang, Yuncai

    2013-04-08

    We demonstrate experimentally and numerically a method using the incoherent delayed self-interference (DSI) of chaotic light from a semiconductor laser with optical feedback to generate wideband chaotic signal. The results show that, the DSI can eliminate the domination of laser relaxation oscillation existing in the chaotic laser light and therefore flatten and widen the power spectrum. Furthermore, the DSI depresses the time-delay signature induced by external cavity modes and improves the symmetry of probability distribution by more than one magnitude. We also experimentally show that this DSI signal is beneficial to the random number generation.

  20. Fiber extended ultra-wideband radar for breath tracking through 10 cm concrete

    DEFF Research Database (Denmark)

    Suhr, Lau Frejstrup; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

    2016-01-01

    This article presents an Ultra-Wideband (UWB) radar with a 20 km NZ-DSF extension on the transmitter side. The radar is based on telecom class signal generation, antennas, and a recording module operating at 20 Gsa/s. The radar is transmitting a pulse covering the frequencies from 3.4 to 9.9 GHz........ The radar system was able to track the breathing of a human through a 10 cm concrete obstacle. The frequency output was verified through the use of a metal pendulum with a fixed oscillation period...

  1. Wideband satellite phase coherent beacon observations at auroral and equatorial latitudes - A review

    International Nuclear Information System (INIS)

    Rino, C.L.; Livingston, R.C.; Cousins, M.D.; Fair, B.C.

    1978-01-01

    This paper presents a brief review of some of the principal results from the first two years of operation of the Wideband satellite which transmits phase-coherent signals from S-band to VHF. The auroral zone data show narrow regions of enhanced scintillation well equatorward of the discrete aurora. Such enhancements can be explained as a purely geometrical effect if the irregularities within the major precipitation regions have a sheet-like structure. Evidence of a localized irregularity source at the poleward boundary of the plasma trough is also found. Model computations are discussed and applied to the interpretation of equatorial data

  2. Up to 35 Gbps Ultra-Wideband Wireless Data Transmission Links

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Rommel, Simon; Vegas Olmos, Juan José

    2016-01-01

    For the first time Ultra-Wideband record data transmission rates up to 35.1 Gbps and 21.6 Gbps are achieved, compliant with the restrictions on the effective radiated power established by both the United States Federal Communications Commission and the European Electronic Communications Committee......, respectively. To achieve these record bit rates, the multi-band approach of Carrierless Amplitude Phase modulation scheme was employed. Wireless transmissions were achieved with a BER below the 7% FEC threshold of 3.8·10-3 ....

  3. An open-structure sound insulator against low-frequency and wide-band acoustic waves

    Science.gov (United States)

    Chen, Zhe; Fan, Li; Zhang, Shu-yi; Zhang, Hui; Li, Xiao-juan; Ding, Jin

    2015-10-01

    To block sound, i.e., the vibration of air, most insulators are based on sealed structures and prevent the flow of the air. In this research, an acoustic metamaterial adopting side structures, loops, and labyrinths, arranged along a main tube, is presented. By combining the accurately designed side structures, an extremely wide forbidden band with a low cut-off frequency of 80 Hz is produced, which demonstrates a powerful low-frequency and wide-band sound insulation ability. Moreover, by virtue of the bypass arrangement, the metamaterial is based on an open structure, and thus air flow is allowed while acoustic waves can be insulated.

  4. Ultra-wideband short-pulse radar with range accuracy for short range detection

    Energy Technology Data Exchange (ETDEWEB)

    Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

    2014-10-07

    An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

  5. Design of an 8-40 GHz Antenna for the Wideband Instrument for Snow Measurements (WISM)

    Science.gov (United States)

    Durham, Timothy E.; Vanhille, Kenneth J.; Trent, Christopher R.; Lambert, Kevin M.; Miranda, Felix A.

    2015-01-01

    This poster describes the implementation of a 6x6 element, dual linear polarized array with beamformer that operates from about 8-40 GHz. It is implemented using a relatively new multi-layer microfabrication process. The beamformer includes baluns that feed dual-polarized differential antenna elements and reactive splitters that cover the full frequency range of operation. This fixed beam array (FBA) serves as the feed for a multi-band instrument designed to measure snow water equivalent (SWE) from an airborne platform known as the Wideband Instrument for Snow Measurements (WISM).

  6. Fiber extended ultra-wideband radar for breath tracking through 10 cm concrete

    DEFF Research Database (Denmark)

    Suhr, Lau Frejstrup; Tafur Monroy, Idelfonso; Vegas Olmos, Juan José

    2016-01-01

    This article presents an Ultra-Wideband (UWB) radar with a 20 km NZ-DSF extension on the transmitter side. The radar is based on telecom class signal generation, antennas, and a recording module operating at 20 Gsa/s. The radar is transmitting a pulse covering the frequencies from 3.4 to 9.9 GHz....... The radar system was able to track the breathing of a human through a 10 cm concrete obstacle. The frequency output was verified through the use of a metal pendulum with a fixed oscillation period...

  7. Proposal of a wide-band mirror polarizer of slow neutrons at a pulsed neutron source

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ostanevich, Yu.M.

    1992-01-01

    The new type wide-band mirror-based neutron polarizer to be operated at a pulsed neutron source is suggested. The idea is to use a movable polarizing mirror system, which, be the incoming beam monochromatized by the time-of-flight, would allow one to tune glancing angles in time so, that the total reflection condition is always fulfilled only for one of the two neutron spin eigenstates. Estimates show, that with the pulsed reactor IBR-2 such polarizer allows one to build a small-angle neutron scattering instrument capable to effectively use the wave-length band from 2 to 15 A. 9 refs.; 1 fig

  8. Wideband aperture array using RF channelizers and massively parallel digital 2D IIR filterbank

    Science.gov (United States)

    Sengupta, Arindam; Madanayake, Arjuna; Gómez-García, Roberto; Engeberg, Erik D.

    2014-05-01

    Wideband receive-mode beamforming applications in wireless location, electronically-scanned antennas for radar, RF sensing, microwave imaging and wireless communications require digital aperture arrays that offer a relatively constant far-field beam over several octaves of bandwidth. Several beamforming schemes including the well-known true time-delay and the phased array beamformers have been realized using either finite impulse response (FIR) or fast Fourier transform (FFT) digital filter-sum based techniques. These beamforming algorithms offer the desired selectivity at the cost of a high computational complexity and frequency-dependant far-field array patterns. A novel approach to receiver beamforming is the use of massively parallel 2-D infinite impulse response (IIR) fan filterbanks for the synthesis of relatively frequency independent RF beams at an order of magnitude lower multiplier complexity compared to FFT or FIR filter based conventional algorithms. The 2-D IIR filterbanks demand fast digital processing that can support several octaves of RF bandwidth, fast analog-to-digital converters (ADCs) for RF-to-bits type direct conversion of wideband antenna element signals. Fast digital implementation platforms that can realize high-precision recursive filter structures necessary for real-time beamforming, at RF radio bandwidths, are also desired. We propose a novel technique that combines a passive RF channelizer, multichannel ADC technology, and single-phase massively parallel 2-D IIR digital fan filterbanks, realized at low complexity using FPGA and/or ASIC technology. There exists native support for a larger bandwidth than the maximum clock frequency of the digital implementation technology. We also strive to achieve More-than-Moore throughput by processing a wideband RF signal having content with N-fold (B = N Fclk/2) bandwidth compared to the maximum clock frequency Fclk Hz of the digital VLSI platform under consideration. Such increase in bandwidth is

  9. Compact electromagnetic bandgap structures for notch band in ultra-wideband applications.

    Science.gov (United States)

    Rotaru, Mihai; Sykulski, Jan

    2010-01-01

    This paper introduces a novel approach to create notch band filters in the front-end of ultra-wideband (UWB) communication systems based on electromagnetic bandgap (EBG) structures. The concept presented here can be implemented in any structure that has a microstrip in its configuration. The EBG structure is first analyzed using a full wave electromagnetic solver and then optimized to work at WLAN band (5.15-5.825 GHz). Two UWB passband filters are used to demonstrate the applicability and effectiveness of the novel EBG notch band feature. Simulation results are provided for two cases studied.

  10. Paper-based inkjet-printed ultra-wideband fractal antennas

    KAUST Repository

    Maza, Armando Rodriguez

    2012-01-01

    For the first time, paper-based inkjet-printed ultra-wideband (UWB) fractal antennas are presented. Two new designs, a miniaturised UWB monopole, which utilises a fractal matching network and is the smallest reported inkjet-printed UWB printed antenna to date, and a fourth-order Koch Snowflake monopole, which utilises a Sierpinski gasket fractal for ink reduction, are demonstrated. It is shown that fractals prove to be a successful method of reducing fabrication costs in inkjet-printed antennas, while retaining or enhancing printed antenna performance. © 2012 The Institution of Engineering and Technology.

  11. 23 CFR 751.7 - Definitions.

    Science.gov (United States)

    2010-04-01

    ... not nonconforming junkyards. (b) Junk. Old or scrap metal, rope, rags, batteries, paper, trash, rubber... relative to Outdoor Advertising Control shall apply insofar as industrial zones are concerned. (e) Unzoned...

  12. Drug Facts

    Medline Plus

    Full Text Available ... Facts Bath Salts Facts Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) Facts Marijuana (Weed, Pot) Facts MDMA ( ... Videos Information About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice (K2) Tobacco/ ...

  13. Street Littering in Nigerian Towns: towards a Framework for ...

    African Journals Online (AJOL)

    Nekky Umera

    behaviour certainly affects everyone's quality of life, gives a visitor a bad first impression and .... sex, education level, occupation, effects of littering, etc.). Levels of .... creams, bananas, junk food, etc) along the streets than older people, as the.

  14. Drug Facts

    Medline Plus

    Full Text Available ... Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) Facts Marijuana (Weed, Pot) Facts MDMA (Ecstasy, Molly) Facts Meth ( ... Information About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice (K2) Tobacco/Nicotine ...

  15. Drug Facts

    Medline Plus

    Full Text Available ... Heroin (Smack, Junk) Facts Marijuana (Weed, Pot) Facts MDMA (Ecstasy, Molly) Facts Meth (Crank, Ice) Facts Pain ... About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice (K2) Tobacco/Nicotine Other ...

  16. Contest Physics.

    Science.gov (United States)

    Moehnke, Randy

    1994-01-01

    Discusses the use of contests to keep physics interesting and exciting for the students. Includes: balloon car, egg drop, tennis ball catapult, bridge building, mousetrap vehicle, musical instrument, slide photo, electric junk dissection, windmill generator, and solar heater. (MVL)

  17. Monika Elisabeth Bründl, Lexikalische Dynamik – Kognitiv ...

    African Journals Online (AJOL)

    Information Technology

    as discussing the "building blocks" which enter into the formation of complex lexemes. ... atomic) semantic feature such as UNPLEASANT JUNK might have served the same ... Bründl discusses this question using bomb as an example (p. 163):.

  18. A Drag Device and Control Algorithm for Spacecraft Attitude Stabilization and De-Orbit Point Targeting using Aerodynamic Drag

    Data.gov (United States)

    National Aeronautics and Space Administration — To reduce the accumulation of human-made "space junk", NASA has implemented a rule requiring the disposal of spacecraft below 2,000 km within 25 years. By deploying...

  19. Health of the street child: the relation between life-style, immunity ...

    African Journals Online (AJOL)

    Erna Kinsey

    system, is a more effective strategy in fighting infection, than conquer- ing invading .... dustbins, parks, cemeteries, old cars, junk yards, drainpipes, sports grounds ... A study on the nutritional status of 97 street children showed that. 74% were ...

  20. The Growing Challenge of "Diabesity"

    Science.gov (United States)

    ... times calories were hard to come by. Today, fast food and junk food are everywhere. Coupled with our increasingly inactive lifestyle, the result is obesity. "Diabetes is everywhere around the world," says Dr. ...

  1. Drug Facts

    Medline Plus

    Full Text Available ... That People Abuse Alcohol Facts Bath Salts Facts Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) Facts Marijuana (Weed, ... Watch Videos Information About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice (K2) ...

  2. Allium hookeri , Thw. Enum. A lesser known terrestrial perennial ...

    African Journals Online (AJOL)

    A lesser known terrestrial perennial herb used as food and its ethnobotanical ... from the wilderness, for consumption and traditional healing of various ailments. ... plants, the lifestyles of the people are changed and they prefer 'junk foods'.

  3. The effect of autumn and spring planting time on seed yield and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-03

    Jun 3, 2008 ... tein sources for human consumption, as well as for feeding animal in many ...... Protein quality of tropical food legumes. J. Sci. Technol. ... Nijhoff/Dr. W. Junk Publishers, The Hague, The Netherlands, pp 7-. 16. Hulse JH ...

  4. Email Updates

    Science.gov (United States)

    ... of this page: https://medlineplus.gov/listserv.html Email Updates To use the sharing features on this ... view your email history or unsubscribe. Prevent MedlinePlus emails from being marked as "spam" or "junk" To ...

  5. Drug Facts

    Medline Plus

    Full Text Available ... Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) Facts Marijuana (Weed, Pot) Facts MDMA (Ecstasy, Molly) Facts Meth (Crank, ... Information About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice (K2) Tobacco/Nicotine ...

  6. Subconjunctival Hemorrhage (Broken Blood Vessel in Eye)

    Science.gov (United States)

    Subconjunctival hemorrhage (broken blood vessel in eye) Overview A subconjunctival hemorrhage (sub-kun-JUNK-tih-vul HEM-uh-ruj) ... may not even realize you have a subconjunctival hemorrhage until you look in the mirror and notice ...

  7. Drug Facts

    Medline Plus

    Full Text Available ... Home Drugs That People Abuse Alcohol Facts Bath Salts Facts Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) ... treatment. Watch Videos Information About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice ( ...

  8. Drug Facts

    Medline Plus

    Full Text Available ... That People Abuse Alcohol Facts Bath Salts Facts Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) Facts Marijuana ( ... Watch Videos Information About Drugs Alcohol Bath Salts Cocaine Heroin Marijuana MDMA Meth Pain Medicines Spice (K2) ...

  9. The Analysis of a Wideband Strip-Helical Antenna with 1.1 Turns

    Directory of Open Access Journals (Sweden)

    Xihui Tang

    2016-01-01

    Full Text Available A wideband strip-helical antenna with 1.1 turns is analyzed numerically and experimentally. By replacing the traditional wire helix with wide metallic strip, the forward traveling current on the strip helix with about one turn smoothly decays to the minimum value at the open end of the helix. Therefore, the strip helix can excite a wideband circular polarization (CP wave with 50-ohm impedance matching. The proposed antenna is printed on a hollow-cylinder with a substrate relative permittivity of εr=2.2 and a thickness of h=0.5 mm. A 50 Ω coaxial cable is directly connected to excite the strip-helical antenna without any additional impedance matching section. The ground plane is placed below the antenna in order to provide a directional radiation pattern. To demonstrate this method, a prototype of 1.1-turn strip-helical antenna is tested. The test shows that the proposed antenna can reach an overlapped bandwidth of 46% with height of 0.52λ0, where λ0 is the wavelength in free space at the center operation frequency.

  10. Statistical Modeling, Simulation, and Experimental Verification of Wideband Indoor Mobile Radio Channels

    Directory of Open Access Journals (Sweden)

    Yuanyuan Ma

    2018-01-01

    Full Text Available This paper focuses on the modeling, simulation, and experimental verification of wideband single-input single-output (SISO mobile fading channels for indoor propagation environments. The indoor reference channel model is derived from a geometrical rectangle scattering model, which consists of an infinite number of scatterers. It is assumed that the scatterers are exponentially distributed over the two-dimensional (2D horizontal plane of a rectangular room. Analytical expressions are derived for the probability density function (PDF of the angle of arrival (AOA, the PDF of the propagation path length, the power delay profile (PDP, and the frequency correlation function (FCF. An efficient sum-of-cisoids (SOC channel simulator is derived from the nonrealizable reference model by employing the SOC principle. It is shown that the SOC channel simulator approximates closely the reference model with respect to the FCF. The SOC channel simulator enables the performance evaluation of wideband indoor wireless communication systems with reduced realization expenditure. Moreover, the rationality and usefulness of the derived indoor channel model is confirmed by various measurements at 2.4, 5, and 60 GHz.

  11. Metasurface base on uneven layered fractal elements for ultra-wideband RCS reduction

    Science.gov (United States)

    Su, Jianxun; Cui, Yueyang; Li, Zengrui; Yang, Yaoqing Lamar; Che, Yongxing; Yin, Hongcheng

    2018-03-01

    A novel metasurface based on uneven layered fractal elements is designed and fabricated for ultra-wideband radar cross section (RCS) reduction in this paper. The proposed metasurface consists of two fractal subwavelength elements with different layer thickness. The reflection phase difference of 180° (±37°) between two unit cells covers an ultra-wide frequency range. Ultra-wideband RCS reduction results from the phase cancellation between two local waves produced by these two unit cells. The diffuse scattering of electromagnetic (EM) waves is caused by the randomized phase distribution, leading to a low monostatic and bistatic RCS simultaneously. This metasurface can achieve -10dB RCS reduction in an ultra-wide frequency range from 6.6 to 23.9 GHz with a ratio bandwidth (fH/fL) of 3.62:1 under normal incidences for both x- and y-polarized waves. Both the simulation and the measurement results are consistent to verify this excellent RCS reduction performance of the proposed metasurface.

  12. Wideband RCS Reduction of Microstrip Array Antenna Based on Absorptive Frequency Selective Surface and Microstrip Resonators

    Directory of Open Access Journals (Sweden)

    Jingjing Xue

    2017-01-01

    Full Text Available An approach for wideband radar cross section (RCS reduction of a microstrip array antenna is presented and discussed. The scheme is based on the microstrip resonators and absorptive frequency selective surface (AFSS with a wideband absorptive property over the low band 1.9–7.5 GHz and a transmission characteristic at high frequency 11.05 GHz. The AFSS is designed to realize the out-of-band RCS reduction and preserve the radiation performance simultaneously, and it is placed above the antenna with the operating frequency of 11.05 GHz. Moreover, the microstrip resonators are loaded to obtain the in-band RCS reduction. As a result, a significant RCS reduction from 1.5 GHz to 13 GHz for both types of polarization has been accomplished. Compared with the reference antenna, the simulated results exhibit that the monostatic RCS of the proposed array antenna in x- and y-polarization can be reduced as much as 17.6 dB and 21.5 dB, respectively. And the measured results agree well with the simulated ones.

  13. Wideband Impulse Modulation and Receiver Algorithms for Multiuser Power Line Communications

    Directory of Open Access Journals (Sweden)

    Andrea M. Tonello

    2007-01-01

    Full Text Available We consider a bit-interleaved coded wideband impulse-modulated system for power line communications. Impulse modulation is combined with direct-sequence code-division multiple access (DS-CDMA to obtain a form of orthogonal modulation and to multiplex the users. We focus on the receiver signal processing algorithms and derive a maximum likelihood frequency-domain detector that takes into account the presence of impulse noise as well as the intercode interference (ICI and the multiple-access interference (MAI that are generated by the frequency-selective power line channel. To reduce complexity, we propose several simplified frequency-domain receiver algorithms with different complexity and performance. We address the problem of the practical estimation of the channel frequency response as well as the estimation of the correlation of the ICI-MAI-plus-noise that is needed in the detection metric. To improve the estimators performance, a simple hard feedback from the channel decoder is also used. Simulation results show that the scheme provides robust performance as a result of spreading the symbol energy both in frequency (through the wideband pulse and in time (through the spreading code and the bit-interleaved convolutional code.

  14. An ultra-wideband pattern reconfigurable antenna based on graphene coating

    Science.gov (United States)

    Jiang, YanNan; Yuan, Rui; Gao, Xi; Wang, Jiao; Li, SiMin; Lin, Yi-Yu

    2016-11-01

    An ultra-wideband pattern reconfigurable antenna is proposed. The antenna is a dielectric coaxial hollow monopole with a cylindrical graphene-based impedance surface coating. It consists of a graphene sheet coated onto the inner surface of a cylindrical substrate and a set of independent polysilicon DC gating pads mounted on the outside of the cylindrical substrate. By changing the DC bias voltages to the different gating pads, the surface impedance of the graphene coating can be freely controlled. Due to the tunability of graphene's surface impedance, the radiation pattern of the proposed antenna can be reconfigured. A transmission line method is used to illustrate the physical mechanism of the proposed antenna. The results show that the proposed antenna can reconfigure its radiation pattern in the omnidirectional mode with the relative bandwidth of 58.5% and the directional mode over the entire azimuth plane with the relative bandwidth of 67%. Project supported by the National Natural Science Foundation of China (Grant Nos. 61661012, 61461016, and 61361005), the Natural Science Foundation of Guangxi, China (Grant Nos. 2015GXNSFBB139003 and 2014GXNSFAA118283), Program for Innovation Research Team of Guilin University of Electromagnetic Technology, China, and the Dean Project of Guangxi Key Laboratory of Wireless Wideband Communication and Signal Processing, China.

  15. Conformal and Spectrally Agile Ultra Wideband Phased Array Antenna for Communication and Sensing

    Science.gov (United States)

    Novak, M.; Alwan, Elias; Miranda, Felix; Volakis, John

    2015-01-01

    There is a continuing need for reducing size and weight of satellite systems, and is also strong interest to increase the functional role of small- and nano-satellites (for instance SmallSats and CubeSats). To this end, a family of arrays is presented, demonstrating ultra-wideband operation across the numerous satellite communications and sensing frequencies up to the Ku-, Ka-, and Millimeter-Wave bands. An example design is demonstrated to operate from 3.5-18.5 GHz with VSWR2 at broadside, and validated through fabrication of an 8 x 8 prototype. This design is optimized for low cost, using Printed Circuit Board (PCB) fabrication. With the same fabrication technology, scaling is shown to be feasible up to a 9-49 GHz band. Further designs are discussed, which extend this wideband operation beyond the Ka-band, for instance from 20-80 GHz. Finally we will discuss recent efforts in the direct integration of such arrays with digital beamforming back-ends. It will be shown that using a novel on-site coding architecture, orders of magnitude reduction in hardware size, power, and cost is accomplished in this transceiver.

  16. A Wideband Magnetoresistive Sensor for Monitoring Dynamic Fault Slip in Laboratory Fault Friction Experiments.

    Science.gov (United States)

    Kilgore, Brian D

    2017-12-02

    A non-contact, wideband method of sensing dynamic fault slip in laboratory geophysical experiments employs an inexpensive magnetoresistive sensor, a small neodymium rare earth magnet, and user built application-specific wideband signal conditioning. The magnetoresistive sensor generates a voltage proportional to the changing angles of magnetic flux lines, generated by differential motion or rotation of the near-by magnet, through the sensor. The performance of an array of these sensors compares favorably to other conventional position sensing methods employed at multiple locations along a 2 m long × 0.4 m deep laboratory strike-slip fault. For these magnetoresistive sensors, the lack of resonance signals commonly encountered with cantilever-type position sensor mounting, the wide band response (DC to ≈ 100 kHz) that exceeds the capabilities of many traditional position sensors, and the small space required on the sample, make them attractive options for capturing high speed fault slip measurements in these laboratory experiments. An unanticipated observation of this study is the apparent sensitivity of this sensor to high frequency electomagnetic signals associated with fault rupture and (or) rupture propagation, which may offer new insights into the physics of earthquake faulting.

  17. Are we Aware of what we are, we are what we Eat- An Epidemiological Survey

    OpenAIRE

    Kaur, Manpreet; M Hegde, Amitha

    2008-01-01

    The lure of convenience in addition to good taste gets people to junk food addiction. With the advent of television even in the remotest areas people have become more aware of the fast food items available. Children watch television where fast food continues to dominate the food advertisements viewed by children. The easily available fast food in and around school campus and with little knowledge of the far reaching effects of these food items consumed, children fall an easy prey to junk food...

  18. Photonic Ultra-Wideband 781.25-Mb/s Signal Generation and Transmission Incorporating Digital Signal Processing Detection

    DEFF Research Database (Denmark)

    Gibbon, Timothy Braidwood; Yu, Xianbin; Tafur Monroy, Idelfonso

    2009-01-01

    The generation of photonic ultra-wideband (UWB) impulse signals using an uncooled distributed-feedback laser is proposed. For the first time, we experimentally demonstrate bit-for-bit digital signal processing (DSP) bit-error-rate measurements for transmission of a 781.25-Mb/s photonic UWB signal...

  19. Design of a planar ultra-wideband four-way power divider/combiner using defected ground structures

    DEFF Research Database (Denmark)

    Squartecchia, Michele; Cimoli, Bruno; Midili, Virginio

    2017-01-01

    This work presents the design of a planar ultra-wideband (UWB) four-way power divider/combiner. A prototype has been fabricated on a printed circuit board and characterized. For achieving the frequency response required in UWB applications, each branch of the divider is conceived as a three...

  20. Ultra-wideband balanced schottky envelope detector for data communication with high bitrate to carrier frequency ratio

    DEFF Research Database (Denmark)

    Granja, Angel Blanco; Cimoli, Bruno; Rodriguez, Sebastian

    2017-01-01

    This paper reports on an ultra-wideband (UWB) Schottky diode based balanced envelope detector for the L-, S-, C- and X- bands. The proposed circuit consists of a balun that splits the input signal into two 180° out of phase signals, a balanced detector, that demodulates the two signals, a low pass...

  1. Impulse radio ultra wide-band over multi-mode fiber for in-home signal distribution

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Rodes, Roberto; Jensen, Jesper Bevensee

    2009-01-01

    We propose and experimentally demonstrate a high speed impulse radio ultra wide-band (IR-UWB) wireless link for in-home network signal distribution. The IR-UWB pulse is distributed over a multimode fiber to the transmitter antenna. Wireless transmitted bit-rates of 1 Gbps at 2 m and 2 Gbps at 1.5 m...

  2. A wideband (3 to 5 GHz) wide-scan connected array of dipoles with low cross polarization

    NARCIS (Netherlands)

    Cavallo, D.; Neto, A.; Gerini, G.

    2012-01-01

    A wideband, wide-scan prototype phased array of connected dipoles has been manufactured and tested from 3 to 5 GHz. The array comprises 7 × 7 elements, each fed by a loop-shaped transformer to avoid common-mode resonances. Such resonances typically affect this type of arrays, with consequent

  3. Head and hand detuning effect study of narrow-band against wide-band mobile phone antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2014-01-01

    Wide-band (WB) and narrow-band (NB) antennas in terms of performance are compared, when interacting with the user’s right head and hand (RHH). The investigations are done through experimental measurements, using standardised head phantom and hand. It is shown that WB antennas detune more than NB ...

  4. The new Wide-band Solar Neutrino Trigger for Super-Kamiokande

    Science.gov (United States)

    Carminati, Giada

    Super-Kamiokande observes low energy electrons induced by the elastic scattering of 8B solar neutrinos. The transition region between vacuum and matter oscillations, with neutrino energy near 3 MeV, is still partially unexplored by any detector. Super-Kamiokande can study this intermediate regime adding a new software trigger. The Wide-band Intelligent Trigger (WIT) has been developed to simultaneously trigger and reconstruct very low energy electrons (above 2.49 kinetic MeV) with an e_ciency close to 100%. The WIT system, comprising 256-Hyperthreaded CPU cores and one 10-Gigabit Ethernet network switch, has been recently installed and integrated in the online DAQ system of SK and the complete system is currently in an advanced status of online data testing.

  5. Biocompatibility of a functionally graded bioceramic coating made by wide-band laser cladding.

    Science.gov (United States)

    Weidong, Zhu; Qibin, Liu; Min, Zheng; Xudong, Wang

    2008-11-01

    The application of plasma spray is the most popular method by which a metal-bioceramic surface composite can be prepared for the repair of biological hard-tissue, but this method has disadvantages. These disadvantages include poor coating-to-substrate adhesion, low mechanical strength, and brittleness of the coating. In the investigation described in this article, a gradient bioceramic coating was prepared on a Ti-6Al-4V titanium alloy surface using a gradient composite design and wide-band laser cladding techniques. Using a trilayer-structure composed of a substratum, an alloy and bioceramics, the coating was chemically and metallurgically bonded with the substratum. The coating, which contains beta-tricalcium phosphate and hydroxyapatite, showed favorable biocompatibility with the bone tissue and promoted in vivo osteogenesis.

  6. On results using automated wideband instrumentation for radar measurements and characterization

    Science.gov (United States)

    Govoni, Mark A.; Dogaru, Traian; Le, Calvin; Sobczak, Kevin

    2017-05-01

    Experiences are shared from a recent radar measurement and characterization effort. A regimented data collection procedure ensures repeatability and provides an expedited alternative to typical narrowband capabilities. Commercially-available instrumentation is repurposed to support wideband data collections spanning a contiguous range of frequencies from 700 MHz to 40 GHz. Utilizing a 4-port network analyzer, both monostatic and quasi-monostatic measurements are achievable. Polarization is varied by way of a custom-designed antenna mount that allows for the mechanical reorientation of the antennas. Computational electromagnetic modeling is briefly introduced and serves in validating the legitimacy of the collection capability. Data products presented will include high-range resolution profiles and inverse synthetic aperture radar (ISAR) imagery.

  7. Statistical behavior of foreshock Langmuir waves observed by the Cluster wideband data plasma wave receiver

    Directory of Open Access Journals (Sweden)

    K. Sigsbee

    2004-07-01

    Full Text Available We present the statistics of Langmuir wave amplitudes in the Earth's foreshock using Cluster Wideband Data (WBD Plasma Wave Receiver electric field waveforms from spacecraft 2, 3 and 4 on 26 March 2002. The largest amplitude Langmuir waves were observed by Cluster near the boundary between the foreshock and solar wind, in agreement with earlier studies. The characteristics of the waves were similar for all three spacecraft, suggesting that variations in foreshock structure must occur on scales greater than the 50-100km spacecraft separations. The electric field amplitude probability distributions constructed using waveforms from the Cluster WBD Plasma Wave Receiver generally followed the log-normal statistics predicted by stochastic growth theory for the event studied. Comparison with WBD receiver data from 17 February 2002, when spacecraft 4 was set in a special manual gain mode, suggests non-optimal auto-ranging of the instrument may have had some influence on the statistics.

  8. Statistical behavior of foreshock Langmuir waves observed by the Cluster wideband data plasma wave receiver

    Directory of Open Access Journals (Sweden)

    K. Sigsbee

    2004-07-01

    Full Text Available We present the statistics of Langmuir wave amplitudes in the Earth's foreshock using Cluster Wideband Data (WBD Plasma Wave Receiver electric field waveforms from spacecraft 2, 3 and 4 on 26 March 2002. The largest amplitude Langmuir waves were observed by Cluster near the boundary between the foreshock and solar wind, in agreement with earlier studies. The characteristics of the waves were similar for all three spacecraft, suggesting that variations in foreshock structure must occur on scales greater than the 50-100km spacecraft separations. The electric field amplitude probability distributions constructed using waveforms from the Cluster WBD Plasma Wave Receiver generally followed the log-normal statistics predicted by stochastic growth theory for the event studied. Comparison with WBD receiver data from 17 February 2002, when spacecraft 4 was set in a special manual gain mode, suggests non-optimal auto-ranging of the instrument may have had some influence on the statistics.

  9. Design Considerations for Autocalibrations of Wide-Band ΔΣ Fractional-N PLL Synthesizers

    Directory of Open Access Journals (Sweden)

    Jaewook Shin

    2011-01-01

    Full Text Available Autocalibration of VCO frequency and loop gain is an essential process in PLL frequency synthesizers. In a wide tuning-range fractional-N PLL frequency synthesizer, high-speed and high-precision automatic calibration is especially important for shortening the lock time and improving the phase noise. This paper reviews the design issues of the PLL auto-calibration and discusses on the limitations of the previous techniques. A very simple and efficient auto-calibration method based on a high-speed frequency-to-digital converter (FDC is proposed and verified through simulations. The proposed method is highly suited for a very wide-band ΔΣ fractional-N PLL.

  10. Networks systems and operations. [wideband communication techniques for data links with satellites

    Science.gov (United States)

    1975-01-01

    The application of wideband communication techniques for data links with satellites is discussed. A diagram of the demand assigned voice communications system is provided. The development of prototype integrated spacecraft paramps at S- and C-bands is described and the performance of space-qualified paramps is tabulated. The characteristics of a dual parabolic cylinder monopulse zoom antenna for use with the tracking and data relay satellite system (TDRSS) are analyzed. The development of a universally applicable transponder at S-band is reported. A block diagram of the major subassemblies of the S-band transponder is included. The technology aspects of network timing and synchronization of communication systems are to show the use of the Omega navigation system. The telemetry data compression system used during the Skylab program is evaluated.

  11. A Compact Wideband Dual-Polarized Antenna with Harmonic Suppression Using Nonuniform Defected Ground Structure

    Directory of Open Access Journals (Sweden)

    Lana Damaj

    2015-01-01

    Full Text Available A wideband dual-polarized coplanar waveguide (CPW fed antenna integrating a wide stop-band filter is presented. The designed filter is based on a nonuniform defected ground structure (DGS in order to obtain a wide stop-band and a compact size. This filter is used to reject harmonics and spurious radiation arising from the RF front end. The complete structure (antenna and filter has been optimized to have a compact size of 0.6×0.6λ02 (λ0 being the free-space wavelength at the lowest operating frequency. The realized antenna operates in the frequency range between 2.7 GHz and 5.9 GHz (bandwidth of about 74%. The isolation between feeding ports is more than 18 dB. The complete structure has a wide stop-band characteristic (103% for harmonic rejection. The simulated numerical results have been confirmed with measurements.

  12. Proposal of a wide-band mirror polarizer of slow neutrons at a pulsed neutron source

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ostanevich, Yu.M.

    1993-01-01

    The new type of wide-band mirror-based neutron polarizer, which is to be operated at a pulsed neutron source, is suggested. The idea is to use a movable polarizing mirror system, which, with the incoming beam monochromatized by the time-of-flight, would allow one to tune glancing angles in time so that the total reflection condition is always fulfilled only for one of the two neutron spin eigenstates. Estimates show that with the pulsed reactor IBR-2 such a polarizer allows one to build a small angle neutron scattering instrument capable of effectively using the wavelength band from 2 A with a rather high luminosity (time-averaged flux at sample position being up to 10 7 n/s/cm -2 ). (orig.)

  13. Ultra Wideband Signal Detection with a Schottky Diode Based Envelope Detector

    DEFF Research Database (Denmark)

    Rommel, Simon; Cimoli, Bruno; Valdecasa, Guillermo Silva

    error correction threshold are achieved for wireless distances of 20 cm and 50 cm at respective data rates of 2.5 Gbit/s and 1.25 Gbit/s. uwb transmission is one of the most attractive alternatives for low-power high-speed wireless communication systems over short distances, its popularity stemming from....... The receiver is able to detect an ultra-wideband signal compliant with the Federal Communications Commission (fcc) regulations for uwb transmission and consisting of a 2.5 Gbit/s non-return-to-zero (nrz) data signal on a 6.9 GHz carrier after 20 cm wireless transmission. Bit error rates (ber) below the forward...... its interoperability with existing wireless services and its license free operation. The latter is conditioned on meeting a number of standards and regulations for maximum radiated powers, designed to ensure the former by defining uwb signals as signals with large bandwidths in the frequency range...

  14. An IQ mismatch calibration and compensation technique for wideband wireless transceivers

    International Nuclear Information System (INIS)

    Peng Jin; Zhou Liguo; Yao Heng; Yuan Fang; Shi Yin; Fang Zhi

    2014-01-01

    An IQ mismatch calibration and compensation technique based on the digital baseband for wideband wireless communication transmitters is proposed. The digital baseband transmits the signal used for IQ mismatch calibration. The signal passes through the RF transmitter path, the calibration loop (which is composed of a square power detector and a band-pass filter in the RF transceiver) and the variable gain amplifier of the receiver. The digital baseband samples the signal for IQ mismatch estimation and compensates for it. Compared with the self-calibration technique in the RF chip, the proposed technique saves area and power consumption for the wireless local area network solution. This technique has been successfully used for the 802.11n system and satisfies the requirement of the standard by achieving over 50 dB image suppression. (semiconductor integrated circuits)

  15. Coherent time-stretch transformation for real-time capture of wideband signals.

    Science.gov (United States)

    Buckley, Brandon W; Madni, Asad M; Jalali, Bahram

    2013-09-09

    Time stretch transformation of wideband waveforms boosts the performance of analog-to-digital converters and digital signal processors by slowing down analog electrical signals before digitization. The transform is based on dispersive Fourier transformation implemented in the optical domain. A coherent receiver would be ideal for capturing the time-stretched optical signal. Coherent receivers offer improved sensitivity, allow for digital cancellation of dispersion-induced impairments and optical nonlinearities, and enable decoding of phase-modulated optical data formats. Because time-stretch uses a chirped broadband (>1 THz) optical carrier, a new coherent detection technique is required. In this paper, we introduce and demonstrate coherent time stretch transformation; a technique that combines dispersive Fourier transform with optically broadband coherent detection.

  16. 3D-Printed Super-Wideband Spidron Fractal Cube Antenna with Laminated Copper

    Directory of Open Access Journals (Sweden)

    Oh Heon Kwon

    2017-09-01

    Full Text Available In this paper, a 3D-printed super-wideband (SWB Spidron fractal cube antenna is proposed. The Spidron fractal configuration is utilized as a self-complementary structure on each face of a 3D frame to attain SWB characteristics. The antenna is excited through a tapered microstrip balun for both mode transforming and impedance matching. A prototype of the proposed antenna, including the 3D frame fabricated with the help of a 3D printer and Spidron fractal patches made of copper tape, is experimentally verified. The measured −10 dB reflection ratio bandwidth is 34:1 (0.44–15.38 GHz. The peak gain varies from 3.42 to 9.29 dBi within the operating frequency bandwidth. The measured radiation patterns are nearly omnidirectional at all operating frequency bands.

  17. Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng; Mao, Haiyang; Li, Zhigang; Liu, Ruiwen; Ming, Anjie [Key laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academic of Sciences, Beijing 100029 (China); Ou, Yi; Ou, Wen [Key laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academic of Sciences, Beijing 100029 (China); Smart Sensor Engineering Center, Jiangsu R& D Center for Internet of Things, Wuxi 214315 (China)

    2015-07-15

    This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequency interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes.

  18. A nonlinear multi-mode wideband piezoelectric vibration-based energy harvester using compliant orthoplanar spring

    Energy Technology Data Exchange (ETDEWEB)

    Dhote, Sharvari, E-mail: sharvari.dhote@mail.utoronto.ca; Zu, Jean; Zhu, Yang [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario M5S-3G8 (Canada)

    2015-04-20

    In this paper, a nonlinear wideband multi-mode piezoelectric vibration-based energy harvester (PVEH) is proposed based on a compliant orthoplanar spring (COPS), which has an advantage of providing multiple vibration modes at relatively low frequencies. The PVEH is made of a tri-leg COPS flexible structure, where three fixed-guided beams are capable of generating strong nonlinear oscillations under certain base excitation. A prototype harvester was fabricated and investigated through both finite-element analysis and experiments. The frequency response shows multiple resonance which corresponds to a hardening type of nonlinear resonance. By adding masses at different locations on the COPS structure, the first three vibration modes are brought close to each other, where the three hardening nonlinear resonances provide a wide bandwidth for the PVEH. The proposed PVEH has enhanced performance of the energy harvester in terms of a wide frequency bandwidth and a high-voltage output under base excitations.

  19. The first observations of wide-band interferometers and the spectra of relic gravitons

    CERN Document Server

    Giovannini, Massimo

    2016-01-01

    Stochastic backgrounds of relic gravitons of cosmological origin extend from frequencies of the order of the aHz up to the GHz range. Since the temperature and polarization anisotropies constrain the low frequency normalization of the spectra, in the concordance paradigm the strain amplitude corresponding to the frequency window of wide-band interferometers turns out to be, approximately, nine orders of magnitude smaller than the astounding signal recently reported and attributed to a binary black hole merger. The backgrounds of relic gravitons expected from the early Universe are compared with the stochastic foregrounds stemming from the estimated multiplicity of the astrophysical sources. It is suggested that while the astrophysical foregrounds are likely to dominate between few Hz and 10 kHz, relic gravitons with frequencies exceeding 100 kHz represent a potentially uncontaminated signal for the next generation of high-frequency detectors currently under scrutiny.

  20. Bandwidth enhancement of a microstrip patch antenna for ultra-wideband applications

    Science.gov (United States)

    Anum, Khanda; Singh, Milind Saurabh; Mishra, Rajan; Tripathi, G. S.

    2018-04-01

    The microstrip antennas are used where size, weight, cost, and performance are constraints. Microstrip antennas (MSA) are being used in many government and commercial applications among which it is mostly used in wireless communication. The proposed antenna is designed for Ultra-wideband (UWB), it is designed on FR4 substrate material with ɛr = 4.3 and 0.0025 loss tangent. The shape and size of patch in microstrip patch antenna plays an important role in its performance. In the proposed antenna design the respective changes have been introduced which includes slotting the feedline,adding a curved slot in patch and change in patch shape itself to improve the bandwidth of the conventional antenna. The simulated results of proposed antenna shows impedance bandwidth (defined by 10 dB return loss) of 2-11.1GHz, VSWRcommunication at 7.25-8.395 GHz.

  1. Ultra-Wideband Phased Array for Millimeter-Wave 5G and ISM

    Science.gov (United States)

    Novak, Markus H.; Volakis, John L.; Miranda, Felix A.

    2016-01-01

    Growing mobile data consumption has prompted the exploration of the millimeter-wave spectrum for large bandwidth, high speed communications. However, the allocated bands are spread across a wide swath of spectrum: fifth generation mobile architecture (5G): 28, 38, 39, 64-71 GHz, as well as Industrial, Scientific, and Medical bands (ISM): 24 and 60 GHz. Moreover, high gain phased arrays are required to overcome the significant path loss associated with these frequencies. Further, it is necessary to incorporate several of these applications in a single, small size and low cost platform. To this end, we have developed a scanning, Ultra-Wideband (UWB) array which covers all 5G, ISM, and other mm-W bands from 24-72 GHz. Critically, this is accomplished using mass-production Printed Circuit Board (PCB) fabrication.

  2. Copper ESEEM and HYSCORE through ultra-wideband chirp EPR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Segawa, Takuya F.; Doll, Andrin; Pribitzer, Stephan; Jeschke, Gunnar, E-mail: gjeschke@ethz.ch [ETH Zurich, Laboratory of Physical Chemistry, Vladimir-Prelog-Weg 2, CH-8093 Zurich (Switzerland)

    2015-07-28

    The main limitation of pulse electron paramagnetic resonance (EPR) spectroscopy is its narrow excitation bandwidth. Ultra-wideband (UWB) excitation with frequency-swept chirp pulses over several hundreds of megahertz overcomes this drawback. This allows to excite electron spin echo envelope modulation (ESEEM) from paramagnetic copper centers in crystals, whereas up to now, only ESEEM of ligand nuclei like protons or nitrogens at lower frequencies could be detected. ESEEM spectra are recorded as two-dimensional correlation experiments, since the full digitization of the electron spin echo provides an additional Fourier transform EPR dimension. Thus, UWB hyperfine-sublevel correlation experiments generate a novel three-dimensional EPR-correlated nuclear modulation spectrum.

  3. 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...

  4. Wideband Channel Modeling for mm-Wave inside Trains for 5G-Related Applications

    Directory of Open Access Journals (Sweden)

    Juan Moreno García-Loygorri

    2018-01-01

    Full Text Available Passenger trains and especially metro trains have been identified as one of the key scenarios for 5G deployments. The wireless channel inside a train car is reported in the frequency range between 26.5 GHz and 40 GHz. These bands have received a lot of interest for high-density scenarios with a high-traffic demand, two of the most relevant aspects of a 5G network. In this paper we provide a full description of the wideband channel estimating Power-Delay Profiles (PDP, Saleh-Valenzuela model parameters, time-of-arrival (TOA ranging, and path-loss results. Moreover, the performance of an automatic clustering algorithm is evaluated. The results show a remarkable degree of coherence and general conclusions are obtained.

  5. Inkjet printing of novel wideband and high gain antennas on low-cost paper substrate

    KAUST Repository

    Cook, Benjamin Stassen

    2012-09-01

    A complete characterization of the inkjet printing process using metallic nanoparticle inks on a paper substrate for microwave frequencies up to 12.5 GHz as well as its application to low-cost, high gain and wideband antenna design are demonstrated in this work. Laser and heat sintering of metallic nanoparticles are compared on paper substrate for the first time which demonstrate immense cost and time benefits of laser sintering. The antennas fabricated using the characterized process include a Vivaldi for the UWB band which exhibits a significantly higher gain of up to 8 dBi as compared to the currently published inkjet printed antennas, and a novel slow-wave log periodic dipole array which employs a new miniaturization technique to show 20% width reduction. © 1963-2012 IEEE.

  6. Utilizing wideband AMC structures for high-gain inkjet-printed antennas on lossy paper substrate

    KAUST Repository

    Cook, Benjamin Stassen

    2013-01-01

    Significant gain and bandwidth improvement of inkjet-printed antennas with integrated artificial magnetic conductor (AMC) is achieved by utilizing wideband ground-backed frequency selective surfaces (FSSs) to overcome the high losses of organic substrates such as paper. A microstrip-fed monopole mounted on an artificial magnetic conductor is demonstrated to improve the gain by 5 dB over previous works and exhibit much wider impedance bandwidth while maintaining a thin antenna profile and a 20% electrical size reduction. The effect of AMC bandwidth on substrate losses and the gain reduction caused by finite AMC array effects are investigated in an effort to produce high-gain, miniaturized, low-cost wearable and structure mount antennas. © 2013 IEEE.

  7. A wideband CMOS inductorless low noise amplifier employing noise cancellation for digital TV tuner applications

    International Nuclear Information System (INIS)

    Zhang Jihong; Bai Xuefei; Huang Lu

    2013-01-01

    A wideband inductorless low noise amplifier for digital TV tuner applications is presented. The proposed LNA scheme uses a composite NMOS/PMOS cross-coupled transistor pair to provide partial cancellation of noise generated by the input transistors. The chip is implemented in SMIC 0.18 μm CMOS technology. Measurement shows that the proposed LNA achieves 12.2–15.2 dB voltage gain from 300 to 900 MHz, the noise figure is below 3.1 dB and has a minimum value of 2.3 dB, and the best input-referred 1-dB compression point (IP1dB) is − 17 dBm at 900 MHz. The core consumes 7 mA current with a supply voltage of 1.8 V and occupies an area of 0.5 × 0.35 mm 2 . (semiconductor integrated circuits)

  8. A Comprehensive Evaluation of Indoor Ranging Using Ultra-Wideband Technology

    Directory of Open Access Journals (Sweden)

    Camillo Gentile

    2007-04-01

    Full Text Available Ultra-wideband technology shows promise for precision ranging due to its fine time resolution to resolve multipath fading and the presence of lower frequencies in the baseband to penetrate walls. While a concerted effort has been conducted in the extensive modeling of the indoor UWB channel in recent years, to our knowledge only two papers have reported ranging performance, but for limited range and fixed bandwidth and center frequency. In principle, boosting power can guarantee connectivity between transmitter and receiver, but not precision due to the distorting effects of walls and other objects in the direct path. In order to gauge the limits of UWB ranging, we carry out 5000 measurements up to an unprecedented 45 m in non-line-of-sight conditions in four separate buildings with dominant wall material varying from sheet rock to steel. In addition, we report performance for varying bandwidth and center frequency of the system.

  9. A Comprehensive Evaluation of Indoor Ranging Using Ultra-Wideband Technology

    Directory of Open Access Journals (Sweden)

    Gentile Camillo

    2007-01-01

    Full Text Available Ultra-wideband technology shows promise for precision ranging due to its fine time resolution to resolve multipath fading and the presence of lower frequencies in the baseband to penetrate walls. While a concerted effort has been conducted in the extensive modeling of the indoor UWB channel in recent years, to our knowledge only two papers have reported ranging performance, but for limited range and fixed bandwidth and center frequency. In principle, boosting power can guarantee connectivity between transmitter and receiver, but not precision due to the distorting effects of walls and other objects in the direct path. In order to gauge the limits of UWB ranging, we carry out 5000 measurements up to an unprecedented 45 m in non-line-of-sight conditions in four separate buildings with dominant wall material varying from sheet rock to steel. In addition, we report performance for varying bandwidth and center frequency of the system.

  10. Wideband Array for C, X, and Ku-Band Applications with 5.3:1 Bandwidth

    Science.gov (United States)

    Novak, Markus H.; Volakis, John L.; Miranda, Felix A.

    2015-01-01

    Planar arrays that exploit strong intentional coupling between elements have allowed for very wide bandwidths in low-profile configurations. However, such designs also require complex impedance matching networks that must also be very compact. For many space applications, typically occurring at C-, X-, Ku-, and most recently at Ka-band, such designs require specialized and expensive fabrication techniques. To address this issue, a novel ultra-wideband array is presented, using a simplified feed network to reduce fabrication cost. The array operates from 3.5-18.5 GHz with VSWR less than 2.4 at broadside, and is of very low profile, having a total height of lambda/10 at the lowest frequency of operation. Validation is provided using a 64-element prototype array, fabricated using common Printed Circuit Board (PCB) technology. The low size, weight, and cost of this array make it attractive for space-borne applications.

  11. Time-domain ultra-wideband radar, sensor and components theory, analysis and design

    CERN Document Server

    Nguyen, Cam

    2014-01-01

    This book presents the theory, analysis, and design of ultra-wideband (UWB) radar and sensor systems (in short, UWB systems) and their components. UWB systems find numerous applications in the military, security, civilian, commercial and medicine fields. This book addresses five main topics of UWB systems: System Analysis, Transmitter Design, Receiver Design, Antenna Design and System Integration and Test. The developments of a practical UWB system and its components using microwave integrated circuits, as well as various measurements, are included in detail to demonstrate the theory, analysis and design technique. Essentially, this book will enable the reader to design their own UWB systems and components. In the System Analysis chapter, the UWB principle of operation as well as the power budget analysis and range resolution analysis are presented. In the UWB Transmitter Design chapter, the design, fabrication and measurement of impulse and monocycle pulse generators are covered. The UWB Receiver Design cha...

  12. Ultra-Wideband Geo-Regioning: A Novel Clustering and Localization Technique

    Directory of Open Access Journals (Sweden)

    Armin Wittneben

    2007-12-01

    Full Text Available Ultra-wideband (UWB technology enables a high temporal resolution of the propagation channel. Consequently, a channel impulse response between transmitter and receiver can be interpreted as signature for their relative positions. If the position of the receiver is known, the channel impulse response indicates the position of the transmitter and vice versa. This work introduces UWB geo-regioning as a clustering and localization method based on channel impulse response fingerprinting, develops a theoretical framework for performance analysis, and evaluates this approach by means of performance results based on measured channel impulse responses. Complexity issues are discussed and performance dependencies on signal-to-noise ratio, a priori knowledge, observation window, and system bandwidth are investigated.

  13. Fractional Calculus Based FDTD Modeling of Layered Biological Media Exposure to Wideband Electromagnetic Pulses

    Directory of Open Access Journals (Sweden)

    Luciano Mescia

    2017-11-01

    Full Text Available Electromagnetic fields are involved in several therapeutic and diagnostic applications such as hyperthermia and electroporation. For these applications, pulsed electric fields (PEFs and transient phenomena are playing a key role for understanding the biological response due to the exposure to non-ionizing wideband pulses. To this end, the PEF propagation in the six-layered planar structure modeling the human head has been studied. The electromagnetic field and the specific absorption rate (SAR have been calculated through an accurate finite-difference time-domain (FDTD dispersive modeling based on the fractional derivative operator. The temperature rise inside the tissues due to the electromagnetic field exposure has been evaluated using both the non-thermoregulated and thermoregulated Gagge’s two-node models. Moreover, additional parametric studies have been carried out with the aim to investigate the thermal response by changing the amplitude and duration of the electric pulses.

  14. Low-sampling-rate ultra-wideband digital receiver using equivalent-time sampling

    KAUST Repository

    Ballal, Tarig

    2014-09-01

    In this paper, we propose an all-digital scheme for ultra-wideband symbol detection. In the proposed scheme, the received symbols are sampled many times below the Nyquist rate. It is shown that when the number of symbol repetitions, P, is co-prime with the symbol duration given in Nyquist samples, the receiver can sample the received data P times below the Nyquist rate, without loss of fidelity. The proposed scheme is applied to perform channel estimation and binary pulse position modulation (BPPM) detection. Results are presented for two receivers operating at two different sampling rates that are 10 and 20 times below the Nyquist rate. The feasibility of the proposed scheme is demonstrated in different scenarios, with reasonable bit error rates obtained in most of the cases.

  15. Ultra-Wideband Array in PCB for Millimeter-Wave 5G and ISM

    Science.gov (United States)

    Novak, Markus H.; Volakis, John L.; Miranda, Felix A.

    2017-01-01

    Growing mobile data consumption has prompted the exploration of the millimeter-wave spectrum for large bandwidth, high speed communications. However, the allocated bands are spread across a wide swath of spectrum: Fifth generation mobile architecture (5G): 28, 38, 39, 6471 GHz; Industrial, Scientific, and Medical bands (ISM): 24, 60 GHz. Moreover, high gain phased arrays are required to overcome the significant path loss associated with these frequencies. Further, it is necessary to incorporate several of these applications in a single, small size and low cost platform. To this end, we have developed a scanning, Ultra-Wideband (UWB) array which covers all 5G, ISM, and other mm-W bands from 2472 GHz. Critically, this is accomplished using mass-production Printed Circuit Board (PCB) fabrication. The results of this work are presented in this poster.

  16. Experimental Characterization of Ultra-Wideband Channel Parameter Measurements in an Underground Mine

    Directory of Open Access Journals (Sweden)

    B. Nkakanou

    2011-01-01

    Full Text Available Experimental results for an ultra-wideband (UWB channel parameters in an underground mining environment over a frequency range of 3 GHz to 10 GHz are reported. The measurements were taken both in LOS and NLOS cases in two different size mine galleries. In the NLOS case, results were acquired for different corridor obstruction angles. The results were obtained during an extensive measurement campaign in the UWB frequency, and the measurement procedure allows both the large- and small-scale parameters such as the path loss exponent, coherence bandwidth, and so forth, to be quantified. The capacity of the UWB channel as a function of the physical depth of the mine gallery has also been recorded for comparison purposes.

  17. Low Energy 8 B Solar Neutrinos with the Wideband Intelligent Trigger at Super-Kamiokande

    Science.gov (United States)

    Elnimr, Muhammad; Super-Kamiokande Collaboration

    2017-09-01

    The water Cherenkov experiment Super-Kamiokande (SK) has accumulated a sample of ˜ 90k solar neutrino data in the past two decades. Currently, the detector measures recoil electrons from solar 8 B neutrino-electron scattering above a kinetic energy of ˜ 3.5 MeV, limited by the capacity of the software trigger, although electrons as low as 2.5 MeV can be reconstructed. The next frontier for the low energy program at Super-K is the current operation of the Wideband Intelligent Trigger (WIT) to push the trigger threshold to the event reconstruction limit of 2.5 MeV. This opens up the possibility to explore the lower energy edge of the Mikheyev-Smirnov-Wolfenstein (MSW) effect in the sun. In this work we will present the prelimiary analysis of the accumlated WIT data taken so far as well as future prospects.

  18. Low-noise wide-band amplifiers for stochastic beam cooling experiments

    International Nuclear Information System (INIS)

    Leskovar, B.; Lo, C.C.

    1982-01-01

    Noise characteristics of the continuous-wave wide-band amplifier systems for stochastic beam cooling experiments are presented. Also, the noise performance, bandwidth capability and gain stability of components used in these amplifiers are summarized and compared in the 100 MHz to 40 GHz frequency range. This includes bipolar and field-effect transistors, parametric amplifier, Schottky diode mixer and maser. Measurements of the noise characteristics and scattering parameters of variety GaAs FETs as a function of ambient temperature are also given. Performance data and design information are presented on a broadband 150-500 MHz preamplifier having noise temperature of approximately 35 0 K at ambient temperature of 20 0 K. An analysis of preamplifier stability based on scattering parameters concept is included

  19. High-resolution imaging using a wideband MIMO radar system with two distributed arrays.

    Science.gov (United States)

    Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

    2010-05-01

    Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method.

  20. Translation compensation and micro-Doppler extraction for precession ballistic targets with a wideband terahertz radar

    Science.gov (United States)

    Yang, Qi; Deng, Bin; Wang, Hongqiang; Zhang, Ye; Qin, Yuliang

    2018-01-01

    Imaging, classification, and recognition techniques of ballistic targets in midcourse have always been the focus of research in the radar field for military applications. However, the high velocity translation of ballistic targets will subject range profile and Doppler to translation, slope, and fold, which are especially severe in the terahertz region. Therefore, a two-step translation compensation method based on envelope alignment is presented. The rough compensation is based on the traditional envelope alignment algorithm in inverse synthetic aperture radar imaging, and the fine compensation is supported by distance fitting. Then, a wideband imaging radar system with a carrier frequency of 0.32 THz is introduced, and an experiment on a precession missile model is carried out. After translation compensation with the method proposed in this paper, the range profile and the micro-Doppler distributions unaffected by translation are obtained, providing an important foundation for the high-resolution imaging and micro-Doppler extraction of the terahertz radar.

  1. Low-complexity Wireless Monitoring of Respiratory Movements Using Ultra-wideband Impulse Response Estimation

    KAUST Repository

    Sana, Furrukh

    2014-03-01

    In this paper; we present a comprehensive scheme for wireless monitoring of the respiratory movements in humans. Our scheme overcomes the challenges low signal-to-noise ratio, background clutter and high sampling rates. It is based on the estimation of the ultra-wideband channel impulse response. We suggest techniques for dealing with background clutter in situations when it might be time variant. We also present a novel methodology for reducing the required sampling rate of the system significantly while achieving the accuracy offered by the Nyquist rate. Performance results from simulations conducted with pre-recorded respiratory signals demonstrate the robustness of our scheme for tackling the above challenges and providing a low-complexity solution for the monitoring of respiratory movements.

  2. Using an interference spectrum as a short-range absolute rangefinder with fiber and wideband source

    Science.gov (United States)

    Hsieh, Tsung-Han; Han, Pin

    2018-06-01

    Recently, a new type of displacement instrument using spectral-interference has been found, which utilizes fiber and a wideband light source to produce an interference spectrum. In this work, we develop a method that measures the absolute air-gap distance by taking wavelengths at two interference spectra minima. The experimental results agree with the theoretical calculations. It is also utilized to produce and control the spectral switch, which is much easier than other previous methods using other control mechanisms. A scanning mode of this scheme for stepped surface measurement is suggested, which is verified by a standard thickness gauge test. Our scheme is different to one available on the market that may use a curve-fitting method, and some comparisons are made between our scheme and that one.

  3. Conjugation of fiber-coupled wide-band light sources and acousto-optical spectral elements

    Science.gov (United States)

    Machikhin, Alexander; Batshev, Vladislav; Polschikova, Olga; Khokhlov, Demid; Pozhar, Vitold; Gorevoy, Alexey

    2017-12-01

    Endoscopic instrumentation is widely used for diagnostics and surgery. The imaging systems, which provide the hyperspectral information of the tissues accessible by endoscopes, are particularly interesting and promising for in vivo photoluminescence diagnostics and therapy of tumour and inflammatory diseases. To add the spectral imaging feature to standard video endoscopes, we propose to implement acousto-optical (AO) filtration of wide-band illumination of incandescent-lamp-based light sources. To collect maximum light and direct it to the fiber-optic light guide inside the endoscopic probe, we have developed and tested the optical system for coupling the light source, the acousto-optical tunable filter (AOTF) and the light guide. The system is compact and compatible with the standard endoscopic components.

  4. Low-sampling-rate ultra-wideband digital receiver using equivalent-time sampling

    KAUST Repository

    Ballal, Tarig; Al-Naffouri, Tareq Y.

    2014-01-01

    In this paper, we propose an all-digital scheme for ultra-wideband symbol detection. In the proposed scheme, the received symbols are sampled many times below the Nyquist rate. It is shown that when the number of symbol repetitions, P, is co-prime with the symbol duration given in Nyquist samples, the receiver can sample the received data P times below the Nyquist rate, without loss of fidelity. The proposed scheme is applied to perform channel estimation and binary pulse position modulation (BPPM) detection. Results are presented for two receivers operating at two different sampling rates that are 10 and 20 times below the Nyquist rate. The feasibility of the proposed scheme is demonstrated in different scenarios, with reasonable bit error rates obtained in most of the cases.

  5. Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever

    International Nuclear Information System (INIS)

    Wu, Meng; Mao, Haiyang; Li, Zhigang; Liu, Ruiwen; Ming, Anjie; Ou, Yi; Ou, Wen

    2015-01-01

    This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequency interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes

  6. A wideband superconducting filter at Ku-band based on interdigital coupling

    Science.gov (United States)

    Jiang, Ying; Wei, Bin; Cao, Bisong; Li, Qirong; Guo, Xubo; Jiang, Linan; Song, Xiaoke; Wang, Xiang

    2018-04-01

    In this paper, an interdigital-type resonator with strong electric coupling is proposed for the wideband high-frequency (>10 GHz) filter design. The proposed microstrip resonator consists of an H-shaped main line part with its both ends installed with interdigital finger parts. Strong electric coupling is achieved between adjacent resonators. A six-pole high-temperature superconducting filter at Ku-band using this resonator is designed and fabricated. The filter has a center frequency of 15.11 GHz with a fractional bandwidth of 30%. The insertion loss of the passband is less than 0.3 dB, and the return loss is greater than 14 dB without any tuning.

  7. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, F

    2007-03-14

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  8. Survey of timing/synchronization of operating wideband digital communications networks

    Science.gov (United States)

    Mitchell, R. L.

    1978-01-01

    In order to benefit from experience gained from the synchronization of operational wideband digital networks, a survey was made of three such systems: Data Transmission Company, Western Union Telegraph Company, and the Computer Communications Group of the Trans-Canada Telephone System. The focus of the survey was on deployment and operational experience from a practical (as opposed to theoretical) viewpoint. The objective was to provide a report on the results of deployment how the systems performed, and wherein the performance differed from that predicted or intended in the design. It also attempted to determine how the various system designers would use the benefit of hindsight if they could design those same systems today.

  9. Design of Wideband Dual-Polarized Planar Antenna Using Multimode Concept

    Directory of Open Access Journals (Sweden)

    Deqiang Yang

    2016-01-01

    Full Text Available A wideband dual-polarized planar antenna is designed and analyzed by using the theory of characteristic modes (TCM. The eigenvalue, eigencurrent, characteristic pattern, and modal weighting coefficient are analyzed to bring physical insight to this kind of antenna. The results demonstrate that there are two modes resonant in the operating band for each polarization, which have been combined to form a wider frequency band. A bandwidth of 60.2% (1.72–3.2 GHz for VSWR < 1.5 with high isolation of 32 dB is achieved simultaneously. The size of the radiator structure is 0.33λ0 × 0.33λ0 × 0.22λ0 (λ0 refers to the center operating frequency.

  10. A Butterfly-Shaped Wideband Microstrip Patch Antenna for Wireless Communication

    Directory of Open Access Journals (Sweden)

    Liling Sun

    2015-01-01

    Full Text Available A novel butterfly-shaped patch antenna for wireless communication is introduced in this paper. The antenna is designed for wideband wireless communications and radio-frequency identification (RFID systems. Two symmetrical quasi-circular arms and two symmetrical round holes are incorporated into the patch of a microstrip antenna to expand its bandwidth. The diameter and position of the circular slots are optimized to achieve a wide bandwidth. The validity of the design concept is demonstrated by means of a prototype having a bandwidth of about 40.1%. The return loss of the butterfly-shaped antenna is greater than 10 dB between 4.15 and 6.36 GHz. The antenna can serve simultaneously most of the modern wireless communication standards.

  11. Ultra-wideband real-time data acquisition in steady-state experiments

    International Nuclear Information System (INIS)

    Nakanishi, Hideya; Ohsuna, Masaki; Kojima, Mamoru; Nonomura, Miki; Emoto, Masahiko; Nagayama, Yoshio; Kawahata, Kazuo; Imazu, Setsuo; Okumura, Haruhiko

    2006-01-01

    The ultra-wideband real-time data acquisition (DAQ) system has started its operation at LHD steady-state experiments since 2004. It uses Compact PCI standard digitizers whose acquisition performance is continuously above 80 MB/s for each frontend, and is also capable of grabbing picture frames from high-resolution cameras. Near the end of the 8th LHD experimental period, it achieved a new world record of 84 GB/shot acquired data during about 4,000 s long-pulse discharge (no.56068). Numbers of real-time and batch DAQ were 15 and 30, respectively. To realize 80 MB/s streaming from the digitizer frontend to data storage and network clients, the acquired data are once buffered on the shared memory to be read by network streaming and data saving tasks independently. The former sends 1/N thinned stream by using a set of TCP and UDP sessions for every monitoring clients, and the latter saves raw data into a series of 10 s chunk files. Afterward, the subdivided segmental compression library 'titz' is applied in migrating them to the mass storage for enabling users to retrieve a smaller chunk of huge data. Different compression algorithms, zlib and JPEG-LS, are automatically applied for waveform picture and data, respectively. Newly made utilities and many improvements, such as acquisition status monitor, real-time waveform monitor, and 64 bit counting in digital timing system, have put the ultra-wideband acquisition system fit for practical use by entire stuff. Demonstrated technologies here could be applied for the next generation fusion experiment like ITER. (author)

  12. Theoretical analysis and simulation of a code division multiple access system (cdma for secure signal transmission in wideband channels

    Directory of Open Access Journals (Sweden)

    Stevan M. Berber

    2014-06-01

    Full Text Available Chaotic spreading sequences can increase secrecy and resistance to interception in signal transmission. Chaos-based CDMA systems have been well investigated in the case of flat fading and noise presence in the channel. However, these systems operating in wideband channels, characterized by the frequency selective fading and white Gaussian noise, have not been investigated to the level of understanding their practical applications. This paper presents a detailed mathematical model of a CDMA system based on chaotic spreading sequences. In a theoretical analysis, all signals are represented in the discrete time domain. Using the theory of discrete time stochastic processes, the probability of error expressions are derived in a closed form for a multi-user chaos based CDMA system. For the sake of comparison, the expressions for the probability of error are derived separately for narrowband and wideband channels. The application of the system interleaving technique is investigated in particular, which showed that this technique can substantially improve probability of error in the system.  The system is simulated and the findings of the simulation confirmed theoretically expected results. Possible improvements in the probability of bit error due to multipath channel nature, with and without interleavers, are quantified depending on the random delay and the number of users in the system. In the analyzed system, a simplified version of the wideband channel model, proposed for modern wideband wireless networks, is used. Introduction Over the past years, the demand for wireless communications has increased substantially due to advancements in mobile communication systems and networks. Following these increasing demands, modern communication systems require the ability to handle a large number of users to process and transmit wideband signals through complex frequency selective channels. One of the techniques for transmission of multi-user signals is the

  13. Analisis experimental de la propagacion en redes de area corporal para la banda de ultra wideband. experimental characterization of the propagation in ultra wideband body area networks

    Science.gov (United States)

    Garcia Serna, Ruben Gregorio

    Diferentes dispositivos capaces de obtener informacion sobre parametros fisiologicos, cinematicos o contextuales del cuerpo pueden interconectarse de manera inalambrica dando lugar a las denominadas Redes de Area Corporal Inalambricas (WBAN, Wireless Body Area Networks). De entre las posibles tecnologias para establecer los enlaces, Ultra Wideband (UWB) esta captando cada vez un mayor interes debido a caracteristicas tales como el bajo nivel de potencia de transmision requerido (bajo nivel de exposicion a campos electromagneticos), el alto ancho de banda disponible y la alta resolucion temporal/espacial. El diseno de sistemas centrados en el cuerpo requiere de modelos de canal que describan de manera precisa la propagacion de senales en este tipo de entornos. Esta tesis se plantea con el objetivo de contribuir al estudio experimental de la propagacion en sistemas centrados en el cuerpo operando en la banda UWB. En primer lugar, se presenta un marco introductorio a las redes WBAN, sus elementos constitutivos, bandas de frecuencia, estandarizacion y modelos de canal. Ademas, se introducen los fundamentos de la tecnologia UWB y sus aplicaciones en este area. Seguidamente, se analiza en terminos de las perdidas de propagacion y la dispersion de retardo la propagacion en el canal off-body entre un transmisor fijo y un dispositivo receptor colocado sobre la superficie del cuerpo de un sujeto. Se considera la influencia de diferentes aspectos, tales como el entorno de medidas, la posicion de colocacion de una antena sobre el cuerpo y la postura adoptada por un sujeto. Finalmente, se analiza el canal de propagacion in-body considerando el movimiento relativo entre dos dispositivos causado por efecto de la respiracion. Las condiciones de propagacion en el interior del cuerpo se emulan por medio de un phantom liquido para UWB y la caracterizacion se plantea tanto en frecuencia, en terminos del modelado de la forma y el ensanchamiento del espectro Doppler, como en tiempo, por

  14. Performance Analysis of Ultra-Wideband Channel for Short-Range Monopulse Radar at Ka-Band

    Directory of Open Access Journals (Sweden)

    Naohiko Iwakiri

    2012-01-01

    Full Text Available High-range resolution is inherently provided with Ka-band ultra-wideband (UWB vehicular radars. The authors have developed a prototype UWB monopulse radar equipped with a two-element receiving antenna array and reported its measurement results. In this paper, a more detailed verification using these measurements is presented. The measurements were analyzed employing matched filtering and eigendecomposition, and then multipath components were extracted to examine the behavior of received UWB monopulse signals. Next, conventional direction finding algorithms based on narrowband assumption were evaluated using the extracted multipath components, resulting in acceptable angle-of-arrival (AOA from the UWB monopulse signal regardless of wideband signals. Performance degradation due to a number of averaging the received monopulses was also examined to design suitable radar's waveforms.

  15. Performance analysis for a chaos-based code-division multiple access system in wide-band channel

    Directory of Open Access Journals (Sweden)

    Ciprian Doru Giurcăneanu

    2015-08-01

    Full Text Available Code-division multiple access technology is widely used in telecommunications and its performance has been extensively investigated in the past. Theoretical results for the case of wide-band transmission channel were not available until recently. The novel formulae which have been published in 2014 can have an important impact on the future of wireless multiuser communications, but limitations come from the Gaussian approximations used in their derivation. In this Letter, the authors obtain more accurate expressions of the bit error rate (BER for the case when the model of the wide-band channel is two-ray, with Rayleigh fading. In the authors’ approach, the spreading sequences are assumed to be generated by logistic map given by Chebyshev polynomial function of order two. Their theoretical and experimental results show clearly that the previous results on BER, which rely on the crude Gaussian approximation, are over-pessimistic.

  16. S – C – L triple wavelength superluminescent source based on an ultra-wideband SOA and FBGs

    International Nuclear Information System (INIS)

    Ahmad, H; Zulkifli, M Z; Hassan, N A; Muhammad, F D; Harun, S W

    2013-01-01

    We propose and demonstrate a wide-band semiconductor optical amplifier (SOA) based triple-wavelength superluminescent source with the output in the S-, C- and L-band regions. The proposed systems uses an ultra-wideband SOA with an amplification range from 1440 to 1620 nm as the linear gain medium. Three fibre Bragg gratings (FBGs) with centre wavelengths of 1500, 1540 and 1580 nm are used to generate the lasing wavelengths in the S-, Cand L-bands respectively, while a variable optical attenuator is used to finely balance the optical powers of the lasing wavelengths. The ultra-wideband SOA generates an amplified spontaneous emission (ASE) spectrum with a peak power of -33 dBm at the highest SOA drive current, and also demonstrates a down-shift in the centre wavelength of the generated spectrum due to the spatial distribution of the carrier densities. The S-band wavelength is the dominant wavelength at high drive currents, with an output power of -6 dBm as compared to the C- and L-bands, which only have powers of -11 and -10 dBm, respectively. All wavelengths have a high average signal-to-noise ratio more than 60 dB at the highest drive current of 390 mA, and the system also shows a high degree of stability, with power fluctuations of less than 3 dB within 70 min. The proposed system can find many applications where a wide-band and stable laser source is crucial, such as in communications and sensing. (control of laser radiation parameters)

  17. S – C – L triple wavelength superluminescent source based on an ultra-wideband SOA and FBGs

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, H; Zulkifli, M Z; Hassan, N A; Muhammad, F D; Harun, S W [Photonics Research Center (Department of Physics), University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2013-10-31

    We propose and demonstrate a wide-band semiconductor optical amplifier (SOA) based triple-wavelength superluminescent source with the output in the S-, C- and L-band regions. The proposed systems uses an ultra-wideband SOA with an amplification range from 1440 to 1620 nm as the linear gain medium. Three fibre Bragg gratings (FBGs) with centre wavelengths of 1500, 1540 and 1580 nm are used to generate the lasing wavelengths in the S-, Cand L-bands respectively, while a variable optical attenuator is used to finely balance the optical powers of the lasing wavelengths. The ultra-wideband SOA generates an amplified spontaneous emission (ASE) spectrum with a peak power of -33 dBm at the highest SOA drive current, and also demonstrates a down-shift in the centre wavelength of the generated spectrum due to the spatial distribution of the carrier densities. The S-band wavelength is the dominant wavelength at high drive currents, with an output power of -6 dBm as compared to the C- and L-bands, which only have powers of -11 and -10 dBm, respectively. All wavelengths have a high average signal-to-noise ratio more than 60 dB at the highest drive current of 390 mA, and the system also shows a high degree of stability, with power fluctuations of less than 3 dB within 70 min. The proposed system can find many applications where a wide-band and stable laser source is crucial, such as in communications and sensing. (control of laser radiation parameters)

  18. Estimating Angle of Arrival (AOA for Wideband Signal by Sensor Delay Line (SDL and Tapped Delay Line (TDL Processors

    Directory of Open Access Journals (Sweden)

    Bassim Sayed Mohammed

    2018-04-01

    Full Text Available Angle of arrival (AOA estimation for wideband signal becomes more necessary for modern communication systems like Global System for Mobile (GSM, satellite, military applications and spread spectrum (frequency hopping and direct sequence. Most of the researchers are focusing on how to cancel the effects of signal bandwidth on AOA estimation performance by using a transversal filter (tap delay line (TDL. Most of the researchers were using two elements array antenna to study these effects. In this research, a general case of proposed (M array elements is used. A transversal filter (TDL in phase adaptive array antenna system is used to calculate the optimum number of taps required to compensate these effect. The proposed system uses a phase adaptive array antenna in conjunction with LMS algorithm to work an angle of arrival (AOA estimator for wideband signals rather than interference canceller. An alternative solution to compensate for the effect of signal bandwidth is proposed by using sensor delay line (SDL instead of fixed delay unit since it has variable time sampling in the time domain and not fixed time delay, depending on the angle of arrival of received signals. The proposed system has the ability to estimate two parameters for received signals simultaneously (the output Signal to Noise Ratio (SNR and AOA, unlike others systems which estimate AOA only. The comparison of the simulation results with Multiple Signal Classification (MUSIC technique showed that the proposed system gives good results for estimating AOA and the output SNR for wideband signals. (SDL processor shows better performance result than (TDL processor. MUSIC technique with both (SDL and (TDL processors shows unacceptable results for estimating (AOA for the wideband signal.

  19. Controls on Magmatic and Hydrothermal Processes at Yellowstone Supervolcano: The Wideband Magnetotelluric Component of an Integrated MT/Seismic Investigation

    Science.gov (United States)

    Schultz, A.; Bennington, N. L.; Bowles-martinez, E.; Imamura, N.; Cronin, R. A.; Miller, D. J.; Hart, L.; Gurrola, R. M.; Neal, B. A.; Scholz, K.; Fry, B.; Carbonari, R.

    2017-12-01

    Previous seismic and magnetotelluric (MT) studies beneath Yellowstone (YS) have provided insight into the origin and migration of magmatic fluids within the volcanic system. However, important questions remain concerning the generation of magmatism at YS, the migration and storage of these magmatic fluids, as well as their relationships to hydrothermal expressions. Analysis of regional-scale EarthScope MT data collected previously suggests a relative absence of continuity in crustal partial melt accumulations directly beneath YS. This is in contrast to some seismic interpretations, although such long-period MT data have limited resolving power in the upper-to-mid crustal section. A wideband MT experiment was designed as a component of an integrated MT/seismic project to examine: the origin and location of magmatic fluids at upper mantle/lower crustal depths, the preferred path of migration for these magmatic fluids into the mid- to upper-crust, the resulting distribution of the magma reservoir, the composition of the magma reservoir, and implications for future volcanism at YS. A high-resolution wideband MT survey was carried out in the YS region in the summer of 2017, with more than forty-five wideband stations installed within and immediately surrounding the YS National Park boundary. These data provided nearly six decades of bandwidth ( 10-3 Hz -to- 103 Hz). Extraordinary permitting restrictions prevented us from using conventional installation methods at many of our sites, and an innovative "no-dig" subaerial method of wideband MT was developed and used successfully. Using these new data along with existing MT datasets, we are inverting for the 3D resistivity structure at upper crustal through upper mantle scales at YS. Complementary to this MT work, a joint inversion for the 3D crustal velocity structure is being carried out using both ambient noise and earthquake travel time data. Taken together, these data should better constrain the crustal velocity

  20. Wideband or Dual-Band Low-Profile Circular Patch Antenna with High Gain and Sidelobe Suppression

    DEFF Research Database (Denmark)

    Squadrito, Paolo; Zhang, Shuai; Pedersen, Gert F.

    2018-01-01

    This paper presents a wideband or dual-band circular disk antenna with high gain and sidelobe suppression (SLS). The antenna has a single layer and single-fed configuration. The antenna can operate with the radiation field superposition of TM12 and TM14 modes at one frequency, which provides high...... gain and SLS. A circle of 10 shorting vias with non-identical diameters are loaded inside the antenna cavity in order to excite the field superposition of TM11 and TM13 modes at another frequency. By modifying the radius of the vias, the resonant frequency with the TM11 and TM13 superposition can...... be tuned closer to or further away from the one with the TM12 and TM14 superposition. In this way, a wideband or dual-band behavior can be obtained with high gain and SLS. The proposed antenna achieves the impedance bandwidth of 6.46% for the wideband case, which is over 6 times wider than the previous...

  1. Investigation on wide-band scattering of a 2-D target above 1-D randomly rough surface by FDTD method.

    Science.gov (United States)

    Li, Juan; Guo, Li-Xin; Jiao, Yong-Chang; Li, Ke

    2011-01-17

    Finite-difference time-domain (FDTD) algorithm with a pulse wave excitation is used to investigate the wide-band composite scattering from a two-dimensional(2-D) infinitely long target with arbitrary cross section located above a one-dimensional(1-D) randomly rough surface. The FDTD calculation is performed with a pulse wave incidence, and the 2-D representative time-domain scattered field in the far zone is obtained directly by extrapolating the currently calculated data on the output boundary. Then the 2-D wide-band scattering result is acquired by transforming the representative time-domain field to the frequency domain with a Fourier transform. Taking the composite scattering of an infinitely long cylinder above rough surface as an example, the wide-band response in the far zone by FDTD with the pulsed excitation is computed and it shows a good agreement with the numerical result by FDTD with the sinusoidal illumination. Finally, the normalized radar cross section (NRCS) from a 2-D target above 1-D rough surface versus the incident frequency, and the representative scattered fields in the far zone versus the time are analyzed in detail.

  2. [The effect of technological parameters of wide-band laser cladding on microstructure and sinterability of gradient bioceramics composite coating].

    Science.gov (United States)

    Liu, Qibin; Zhu, Weidong; Zou, Longjiang; Zheng, Min; Dong, Chuang

    2005-12-01

    The gradient bioceramics coating was prepared on the surface of Ti-6Al-4V alloy by using wide-band laser cladding. And the effect of technological parameters of wide-band laser cladding on microstructure and sinterability of gradient bioceramics composite coating was studied. The experimental results indicated that in the circumstances of size of laser doze D and scanning velocity V being fixed, with the increasement of power P, the density of microstructure in bioceramics coating gradually degraded; with the increasement of power P, the pore rate of bioceramics gradually became high. While P = 2.3 KW, the bioceramics coating with dense structure and lower pore rate (5.11%) was obtained; while P = 2.9 KW, the bioceramics coating with disappointing density was formed and its pore rate was up to 21.32%. The microhardness of bioceramics coating demonstrated that while P = 2.3 KW, the largest value of microhardness of bioceramics coating was 1100 HV. Under the condition of our research work, the optimum technological parameters for preparing gradient bioceramics coating by wide-band laser cladding are: P = 2.3 KW, V = 145 mm/min, D = 16 mm x 2 mm.

  3. Investigation on cored-eutectic structure in Ni60/WC composite coatings fabricated by wide-band laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qunshuang, E-mail: maqunshuang@126.com; Li, Yajiang, E-mail: yajli@sdu.edu.cn; Wang, Juan, E-mail: jwang@sdu.edu.cn; Liu, Kun, E-mail: liu_kun@163.com

    2015-10-05

    Highlights: • Perfect composite coatings were fabricated using wide-band laser cladding. • Special cored-eutectic structure was synthesized in Ni60/WC composite coatings. • Cored-eutectic consists of hard carbide compounds and fine lamellar eutectic of M{sub 23}C{sub 6} carbides and γ-Ni(Fe). • Wear resistance of coating layer was significantly improved due to precipitation of M{sub 23}C{sub 6} carbides. - Abstract: Ni60 composite coatings reinforced with WC particles were fabricated on the surface of Q550 steel using LDF4000-100 fiber laser device. The wide-band laser and circular beam laser used in laser cladding were obtained by optical lens. Microstructure, elemental distribution, phase constitution and wear properties of different composite coatings were investigated. The results showed that WC particles were partly dissolved under the effect of wide-band fiber laser irradiation. A special cored-eutectic structure was synthesized due to dissolution of WC particles. According to EDS and XRD results, the inside cores were confirmed as carbides of M{sub 23}C{sub 6} enriched in Cr, W and Fe. These complex carbides were primarily separated out in the molten metal when solidification started. Eutectic structure composed of M{sub 23}C{sub 6} carbides and γ-Ni(Fe) grew around carbides when cooling. Element content of Cr and W is lower at the bottom of cladding layer. In consequence, the eutectic structure formed in this region did not have inside carbides. The coatings made by circular laser beam were composed of dendritic matrix and interdendritic eutectic carbides, lacking of block carbides. Compared to coatings made by circular laser spot, the cored-eutectic structure formed in wide-band coatings had advantages of well-distribution and tight binding with matrix. The uniform power density and energy distribution and the weak liquid convection in molten pool lead to the unique microstructure evolution in composite coatings made by wide-band laser

  4. Integrated Ultra-Wideband Tracking and Carbon Dioxide Sensing System Design for International Space Station Applications

    Science.gov (United States)

    Ni, Jianjun (David); Hafermalz, David; Dusl, John; Barton, Rick; Wagner, Ray; Ngo, Phong

    2015-01-01

    A three-dimensional (3D) Ultra-Wideband (UWB) Time-of-Arrival (TOA) tracking system has been studied at NASA Johnson Space Center (JSC) to provide the tracking capability inside the International Space Station (ISS) modules for various applications. One of applications is to locate and report the location where crew experienced possible high level of carbon-dioxide (CO2) and felt upset. Recent findings indicate that frequent, short-term crew exposure to elevated CO2 levels combined with other physiological impacts of microgravity may lead to a number of detrimental effects, including loss of vision. To evaluate the risks associated with transient elevated CO2 levels and design effective countermeasures, doctors must have access to frequent CO2 measurements in the immediate vicinity of individual crew members along with simultaneous measurements of their location in the space environment. To achieve this goal, a small, low-power, wearable system that integrates an accurate CO2 sensor with an ultra-wideband (UWB) radio capable of real-time location estimation and data communication is proposed. This system would be worn by crew members or mounted on a free-flyer and would automatically gather and transmit sampled sensor data tagged with real-time, high-resolution location information. Under the current proposed effort, a breadboard prototype of such a system has been developed. Although the initial effort is targeted to CO2 monitoring, the concept is applicable to other types of sensors. For the initial effort, a micro-controller is leveraged to integrate a low-power CO2 sensor with a commercially available UWB radio system with ranging capability. In order to accurately locate those places in a multipath intensive environment like ISS modules, it requires a robust real-time location system (RTLS) which can provide the required accuracy and update rate. A 3D UWB TOA tracking system with two-way ranging has been proposed and studied. The designed system will be tested

  5. Development of a Diagnostic Prediction Model for Conductive Conditions in Neonates Using Wideband Acoustic Immittance.

    Science.gov (United States)

    Myers, Joshua; Kei, Joseph; Aithal, Sreedevi; Aithal, Venkatesh; Driscoll, Carlie; Khan, Asaduzzaman; Manuel, Alehandrea; Joseph, Anjali; Malicka, Alicja N

    2018-03-03

    Wideband acoustic immittance (WAI) is an emerging test of middle-ear function with potential applications for neonates in screening and diagnostic settings. Previous large-scale diagnostic accuracy studies have assessed the performance of WAI against evoked otoacoustic emissions, but further research is needed using a more stringent reference standard. Research into suitable quantitative techniques to analyze the large volume of data produced by WAI is still in its infancy. Prediction models are an attractive method for analysis of multivariate data because they provide individualized probabilities that a subject has the condition. A clinically useful prediction model must accurately discriminate between normal and abnormal cases and be well calibrated (i.e., give accurate predictions). The present study aimed to develop a diagnostic prediction model for detecting conductive conditions in neonates using WAI. A stringent reference standard was created by combining results of high-frequency tympanometry and distortion product otoacoustic emissions. High-frequency tympanometry and distortion product otoacoustic emissions were performed on both ears of 629 healthy neonates to assess outer- and middle-ear function. Wideband absorbance and complex admittance (magnitude and phase) were measured at frequencies ranging from 226 to 8000 Hz in each neonate at ambient pressure using a click stimulus. Results from one ear of each neonate were used to develop the prediction model. WAI results were used as logistic regression predictors to model the probability that an ear had outer/middle-ear dysfunction. WAI variables were modeled both linearly and nonlinearly, to test whether allowing nonlinearity improved model fit and thus calibration. The best-fitting model was validated using the opposite ears and with bootstrap resampling. The best-fitting model used absorbance at 1000 and 2000 Hz, admittance magnitude at 1000 and 2000 Hz, and admittance phase at 1000 and 4000 Hz modeled

  6. An ultra-sensitive and wideband magnetometer based on a superconducting quantum interference device

    Science.gov (United States)

    Storm, Jan-Hendrik; Hömmen, Peter; Drung, Dietmar; Körber, Rainer

    2017-02-01

    The magnetic field noise in superconducting quantum interference devices (SQUIDs) used for biomagnetic research such as magnetoencephalography or ultra-low-field nuclear magnetic resonance is usually limited by instrumental dewar noise. We constructed a wideband, ultra-low noise system with a 45 mm diameter superconducting pick-up coil inductively coupled to a current sensor SQUID. Thermal noise in the liquid helium dewar is minimized by using aluminized polyester fabric as superinsulation and aluminum oxide strips as heat shields. With a magnetometer pick-up coil in the center of the Berlin magnetically shielded room 2 (BMSR2), a noise level of around 150 aT Hz-1/2 is achieved in the white noise regime between about 20 kHz and the system bandwidth of about 2.5 MHz. At lower frequencies, the resolution is limited by magnetic field noise arising from the walls of the shielded room. Modeling the BMSR2 as a closed cube with continuous μ-metal walls, we can quantitatively reproduce its measured field noise.

  7. WIDE-BAND SPECTRA OF GIANT RADIO PULSES FROM THE CRAB PULSAR

    Energy Technology Data Exchange (ETDEWEB)

    Mikami, Ryo; Asano, Katsuaki [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Tanaka, Shuta J. [Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo, 658-8501 (Japan); Kisaka, Shota [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa, 252-5258 (Japan); Sekido, Mamoru; Takefuji, Kazuhiro [Kashima Space Technology Center, National Institute of Information and Communications Technology, Kashima, Ibaraki 314-8501 (Japan); Takeuchi, Hiroshi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan); Misawa, Hiroaki; Tsuchiya, Fuminori [Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Kita, Hajime [Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Yonekura, Yoshinori [Center for Astronomy, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan); Terasawa, Toshio, E-mail: mikami@icrr.u-tokyo.ac.jp, E-mail: asanok@icrr.u-tokyo.ac.jp [iTHES Research Group, RIKEN, Wako, Saitama 351-0198 (Japan)

    2016-12-01

    We present the results of the simultaneous observation of giant radio pulses (GRPs) from the Crab pulsar at 0.3, 1.6, 2.2, 6.7, and 8.4 GHz with four telescopes in Japan. We obtain 3194 and 272 GRPs occurring at the main pulse and the interpulse phases, respectively. A few GRPs detected at both 0.3 and 8.4 GHz are the most wide-band samples ever reported. In the frequency range from 0.3 to 2.2 GHz, we find that about 70% or more of the GRP spectra are consistent with single power laws and their spectral indices are distributed from −4 to −1. We also find that a significant number of GRPs have such a hard spectral index (approximately −1) that the fluence at 0.3 GHz is below the detection limit (“dim-hard” GRPs). Stacking light curves of such dim-hard GRPs at 0.3 GHz, we detect consistent enhancement compared to the off-GRP light curve. Our samples show apparent correlations between the fluences and the spectral hardness, which indicates that more energetic GRPs tend to show softer spectra. Our comprehensive studies on the GRP spectra are useful materials to verify the GRP model of fast radio bursts in future observations.

  8. Analysis of a Compact Wideband Slotted Antenna for Ku Band Applications

    Directory of Open Access Journals (Sweden)

    M. R. Ahsan

    2014-01-01

    Full Text Available The design procedure and physical module of a compact wideband patch antenna for Ku band application are presented in this paper. Finite element method based on 3D electromagnetic field solver has been utilized for the designing and analyzing process of proposed microstrip line fed modified E-H shaped electrically small patch antenna. After successful completion of the design process through various simulations, the proposed antenna has been fabricated on printed circuit board (PCB and its characteristics have been studied. The parameters of the proposed antenna prototype have been measured in standard far-field rectangular shape anechoic measurement compartment. It is apparent from the measured antenna parameters that the proposed antenna achieved almost stable variation of radiation pattern over the entire operational band with 1380 MHz of -10 dB return loss bandwidth. The maximum gain of 7.8 dBi and 89.97% average efficiency within the operating band from 17.15 GHz to 18.53 GHz ensure the suitability of the proposed antenna for Ku band applications.

  9. Elaborate analysis and design of filter-bank-based sensing for wideband cognitive radios

    Science.gov (United States)

    Maliatsos, Konstantinos; Adamis, Athanasios; Kanatas, Athanasios G.

    2014-12-01

    The successful operation of a cognitive radio system strongly depends on its ability to sense the radio environment. With the use of spectrum sensing algorithms, the cognitive radio is required to detect co-existing licensed primary transmissions and to protect them from interference. This paper focuses on filter-bank-based sensing and provides a solid theoretical background for the design of these detectors. Optimum detectors based on the Neyman-Pearson theorem are developed for uniform discrete Fourier transform (DFT) and modified DFT filter banks with root-Nyquist filters. The proposed sensing framework does not require frequency alignment between the filter bank of the sensor and the primary signal. Each wideband primary channel is spanned and monitored by several sensor subchannels that analyse it in narrowband signals. Filter-bank-based sensing is proved to be robust and efficient under coloured noise. Moreover, the performance of the weighted energy detector as a sensing technique is evaluated. Finally, based on the Locally Most Powerful and the Generalized Likelihood Ratio test, real-world sensing algorithms that do not require a priori knowledge are proposed and tested.

  10. Wideband analysis of railway catenary line radiation and new applications of its unintentional emitted signals

    Science.gov (United States)

    Heddebaut, Marc; Deniau, Virginie; Rioult, Jean

    2018-06-01

    Generally, in railway networks, dissipated energy—and its consequences in terms of noise, ballast attrition, electromagnetic interference, etc—is considered a nuisance generated by this means of transport. Therefore, most studies are carried out with the aim of reducing it. This paper takes the opposite view and considers the particular case of the irreducible electromagnetic interference generated along an electrified line, in order to propose new applications beneficial to railway operations. At a selected representative location, wideband (ranging from 10 kHz to 1 GHz) electromagnetic field measurements are performed successively during, and not during, high speed train passages. We deduce two potential applications of these unintentional signals. At low frequency, the first proposal considers energy harvesting using the received electromagnetic interference as the source. This received energy can be converted and used to DC feed low consumption sensors to be installed along the railway infrastructure. These sensors participate in monitoring infrastructure health and in making it more resilient to internal and external stresses. At higher frequencies, for the second proposal, radiation from the catenary line and train pantograph is specifically examined at a carefully selected sub-band. The results are also studied following a time–frequency analysis, to introduce a new nondestructive inspection method of the sliding contact between the catenary line and the train pantograph. Ultimately, this technique could offer a new means of monitoring the health of both the catenary line and the pantograph.

  11. Calculation of wideband ultrasonic fields radiated by immersed transducers into solids

    International Nuclear Information System (INIS)

    Lhemery, A.; Calmon, P.; Mephane, M.

    1996-01-01

    In ultrasonic nondestructive testing (NDT), configurations of immersion techniques where transducers radiate through non-planar interfaces are often encountered, e.g., pipe inspection where the probe can be scanned either inside or outside the pipe. When local radii of curvature are far larger that typical wave paths in the coupling fluid and into the piece, field predictions can often be made assuming a plane interface. For smaller radii, such an approximation is not valid. The model developed at the French Atomic ENergy Commission (CEA) to predict ultrasonic fields radiated by wideband transducers through liquid-interfaces (called Champ-Sons) is based on a modification of the Rayleigh integral to take account of refraction. It is derived under the geometrical optics approximation (GO) which introduces two factors: the transmission coefficient between the two media of elementary contributions from source-points to field-points and the so-called 'divergence factor' of the transmitted rays (denoted by DF), accounting for the principal radii of curvature of the retransmitted rays (denoted by DF), accounting for the principal radii of curvature of the refracted wave fronts (initially spherical in the coupling medium). (authors)

  12. Low-sampling-rate ultra-wideband channel estimation using a bounded-data-uncertainty approach

    KAUST Repository

    Ballal, Tarig

    2014-01-01

    This paper proposes a low-sampling-rate scheme for ultra-wideband channel estimation. In the proposed scheme, P pulses are transmitted to produce P observations. These observations are exploited to produce channel impulse response estimates at a desired sampling rate, while the ADC operates at a rate that is P times less. To avoid loss of fidelity, the interpulse interval, given in units of sampling periods of the desired rate, is restricted to be co-prime with P. This condition is affected when clock drift is present and the transmitted pulse locations change. To handle this situation and to achieve good performance without using prior information, we derive an improved estimator based on the bounded data uncertainty (BDU) model. This estimator is shown to be related to the Bayesian linear minimum mean squared error (LMMSE) estimator. The performance of the proposed sub-sampling scheme was tested in conjunction with the new estimator. It is shown that high reduction in sampling rate can be achieved. The proposed estimator outperforms the least squares estimator in most cases; while in the high SNR regime, it also outperforms the LMMSE estimator. © 2014 IEEE.

  13. Design Studies of Ultra-Wideband Microstrip Antennas with a Small Capacitive Feed

    Directory of Open Access Journals (Sweden)

    Veeresh G. Kasabegoudar

    2007-01-01

    Full Text Available The design of an ultra-wideband microstrip patch antenna with a small coplanar capacitive feed strip is presented. The proposed rectangular patch antenna provides an impedance bandwidth of nearly 50%, and has stable radiation patterns for almost all frequencies in the operational band. Results presented here show that such wide bandwidths are also possible for triangular and semiellipse geometries with a similar feed arrangement. The proposed feed is a very small strip placed very close to the radiator on a substrate above the ground plane. Shape of the feed strip can also be different, so long as the area is not changed. Experimental results agree with the simulated results. Effects of key design parameters such as the air gap between the substrate and the ground plane, the distance between radiator patch and feed strip, and the dimensions of the feed strip on the input characteristics of the antenna have been investigated and discussed. As demonstrated here, the proposed antenna can be redesigned for any frequency in the L-, S-, C-, or X-band. A design criterion for the air gap has been empirically obtained to enable maximum antenna bandwidth for all these operational frequencies.

  14. Design of CMOS RFIC ultra-wideband impulse transmitters and receivers

    CERN Document Server

    Nguyen, Cam

    2017-01-01

    This book presents the design of ultra-wideband (UWB) impulse-based transmitter and receiver frontends, operating within the 3.1-10.6 GHz frequency band, using CMOS radio-frequency integrated-circuits (RFICs). CMOS RFICs are small, cheap, low power devices, better suited for direct integration with digital ICs as compared to those using III-V compound semiconductor devices. CMOS RFICs are thus very attractive for RF systems and, in fact, the principal choice for commercial wireless markets.  The book comprises seven chapters. The first chapter gives an introduction to UWB technology and outlines its suitability for high resolution sensing and high-rate, short-range ad-hoc networking and communications. The second chapter provides the basics of CMOS RFICs needed for the design of the UWB RFIC transmitter and receiver presented in this book. It includes the design fundamentals, lumped and distributed elements for RFIC, layout, post-layout simulation, and measurement. The third chapter discusses the basics of U...

  15. Continuously tunable S and C+L bands ultra wideband erbium-doped fiber ring laser

    International Nuclear Information System (INIS)

    Wang, Q; Yu, Q X

    2009-01-01

    This paper presents an ultra wideband tunable silica-based erbium doped fiber ring laser (EDFRL) that can be continuously tuned in S and C+L bands from 1475 to 1619 nm. It is the first time that a fiber ring laser's tuning range reaches 144 nm using a standard silica-based C-band erbium-doped fiber as gain media. In the laser configuration two isolators are used in the fiber loop for suppressing the ASE in C-band and elevating the lasing gain in S-band. As a result the available lasing wavelength is extended toward the shorter wavelength of the gain bandwidth. The optimized erbium-doped fiber length, output coupling ratio and pumping laser power have been obtained through experimental study. This ring fiber laser has simple configuration, low threshold, flat laser spectral distribution and high signal-to-ASE-noise ratio. The laser will have many potential applications in fiber sensor wavelength interrogation, high-resolution spectroscopy and fiber optic communications

  16. A localized cooperative wideband spectrum sensing for dynamic access of TV bands using RF sensor networks

    KAUST Repository

    Mirza, Mohammed

    2011-07-01

    In this paper we address and simulate a Radio Frequency (RF) sensor network for a cooperative spectrum sensing and localization scheme. The proposed method integrates a Wavelet based Multi-Resolution Spectrum Sensing (MRSS), an N-bit hard combination technique for cooperative decision making and a Received Signal Strength (RSS) based localization algorithm to detect the availability of frequency bands and the location of the usable base station. We develop an N-bit hard combination technique and compare its performance to a traditionally used 2-bit hard combination for cooperative sensing. The key idea is to design a novel RF sensor network based cooperative wideband spectrum sensing and localization scheme by using a wavelet based Multi-Resolution Spectrum Sensing (MRSS) and Received Signal Strength (RSS) Localization techniques which were originally proposed for cognitive radio applications. The performance evaluations are also done to show the different detection accuracies for varying parameters such as number of sensor nodes, Signal to Noise Ratios (SNR) and number of averaged Power Spectral Densities (PSD). The proposed scheme improves the problems of shadowing, fading and noise. In addition, the RSS based localization technique was shown to be an acceptable means of estimating the position of the available transmitter. © 2011 IEEE.

  17. Jitter-Robust Orthogonal Hermite Pulses for Ultra-Wideband Impulse Radio Communications

    Directory of Open Access Journals (Sweden)

    Ryuji Kohno

    2005-03-01

    Full Text Available The design of a class of jitter-robust, Hermite polynomial-based, orthogonal pulses for ultra-wideband impulse radio (UWB-IR communications systems is presented. A unified and exact closed-form expression of the auto- and cross-correlation functions of Hermite pulses is provided. Under the assumption that jitter values are sufficiently smaller than pulse widths, this formula is used to decompose jitter-shifted pulses over an orthonormal basis of the Hermite space. For any given jitter probability density function (pdf, the decomposition yields an equivalent distribution of N-by-N matrices which simplifies the convolutional jitter channel model onto a multiplicative matrix model. The design of jitter-robust orthogonal pulses is then transformed into a generalized eigendecomposition problem whose solution is obtained with a Jacobi-like simultaneous diagonalization algorithm applied over a subset of samples of the channel matrix distribution. Examples of the waveforms obtained with the proposed design and their improved auto- and cross-correlation functions are given. Simulation results are presented, which demonstrate the superior performance of a pulse-shape modulated (PSM- UWB-IR system using the proposed pulses, over the same system using conventional orthogonal Hermite pulses, in jitter channels with additive white Gaussian noise (AWGN.

  18. Uneven-Layered Coding Metamaterial Tile for Ultra-wideband RCS Reduction and Diffuse Scattering.

    Science.gov (United States)

    Su, Jianxun; He, Huan; Li, Zengrui; Yang, Yaoqing Lamar; Yin, Hongcheng; Wang, Junhong

    2018-05-25

    In this paper, a novel uneven-layered coding metamaterial tile is proposed for ultra-wideband radar cross section (RCS) reduction and diffuse scattering. The metamaterial tile is composed of two kinds of square ring unit cells with different layer thickness. The reflection phase difference of 180° (±37°) between two unit cells covers an ultra-wide frequency range. Due to the phase cancellation between two unit cells, the metamaterial tile has the scattering pattern of four strong lobes deviating from normal direction. The metamaterial tile and its 90-degree rotation can be encoded as the '0' and '1' elements to cover an object, and diffuse scattering pattern can be realized by optimizing phase distribution, leading to reductions of the monostatic and bi-static RCSs simultaneously. The metamaterial tile can achieve -10 dB RCS reduction from 6.2 GHz to 25.7 GHz with the ratio bandwidth of 4.15:1 at normal incidence. The measured and simulated results are in good agreement and validate the proposed uneven-layered coding metamaterial tile can greatly expanding the bandwidth for RCS reduction and diffuse scattering.

  19. Ultra-wideband circular-polarization converter with micro-split Jerusalem-cross metasurfaces

    Science.gov (United States)

    Gao, Xi; Yu, Xing-Yang; Cao, Wei-Ping; Jiang, Yan-Nan; Yu, Xin-Hua

    2016-12-01

    An ultrathin micro-split Jerusalem-cross metasurface is proposed in this paper, which can efficiently convert the linear polarization of electromagnetic (EM) wave into the circular polarization in ultra-wideband. By symmetrically employing two micro-splits on the horizontal arm (in the x direction) of the Jerusalem-cross structure, the bandwidth of the proposed device is significantly extended. Both simulated and experimental results show that the proposed metasurface is able to convert linearly polarized waves into circularly polarized waves in a frequency range from 12.4 GHz to 21 GHz, with an axis ratio better than 1 dB. The simulated results also show that such a broadband and high-performance are maintained over a wide range of incident angle. The presented polarization converter can be used in a number of areas, such as spectroscopy and wireless communications. Project supported by the National Natural Science Foundation of China (Grant Nos. 61461016 and 61661012), the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant Nos. 2014GXNSFAA118366, 2014GXNSFAA118283, and 2015jjBB7002), and the Innovation Project of Graduate Education of Guilin University of Electronic Technology, China (Grant No. 2016YJCX82).

  20. Adaptive Space-Time-Spreading-Assisted Wideband CDMA Systems Communicating over Dispersive Nakagami- Fading Channels

    Directory of Open Access Journals (Sweden)

    Yang Lie-Liang

    2005-01-01

    Full Text Available In this contribution, the performance of wideband code-division multiple-access (W-CDMA systems using space-time-spreading- (STS- based transmit diversity is investigated, when frequency-selective Nakagami- fading channels, multiuser interference, and background noise are considered. The analysis and numerical results suggest that the achievable diversity order is the product of the frequency-selective diversity order and the transmit diversity order. Furthermore, both the transmit diversity and the frequency-selective diversity have the same order of importance. Since W-CDMA signals are subjected to frequency-selective fading, the number of resolvable paths at the receiver may vary over a wide range depending on the transmission environment encountered. It can be shown that, for wireless channels where the frequency selectivity is sufficiently high, transmit diversity may be not necessitated. Under this case, multiple transmission antennas can be leveraged into an increased bitrate. Therefore, an adaptive STS-based transmission scheme is then proposed for improving the throughput of W-CDMA systems. Our numerical results demonstrate that this adaptive STS-based transmission scheme is capable of significantly improving the effective throughput of W-CDMA systems. Specifically, the studied W-CDMA system's bitrate can be increased by a factor of three at the modest cost of requiring an extra 0.4 dB or 1.2 dB transmitted power in the context of the investigated urban or suburban areas, respectively.