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1
Brown, Bryant. "Fat Bone Ratio: A New Measurement of Obesity." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/623227.
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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.Importance: This study proposed a new radiographic measure of obesity that is a better predictive indicator of obesity‐related risk: Fat/Bone Ratio. Primary Objective: Does the Fat/Bone Ratio correlate with obesity. Secondary Objective: Does the Fat/Bone Ratio correlate more closely with the comorbidities of obesity as compared to BMI. Design: Retrospective review of 2703 upright posterior‐anterior (PA) and lateral chest radiographs obtained from June 2013 through May 2014. The soft tissue height overlying the acromioclavicular joint was calculated and divided by the mid‐clavicle width to determine the Fat/Bone Ratio. Comorbidities of obesity were determined through chart review. Setting: Adult community emergency department. Participants: All adults (age greater than 18). Main Outcomes and Measures: BMI, Fat/Bone Ratio, comorbidities: hypertension, obstructive sleep apnea, osteoarthritis, hyperlipidemia, atherosclerosis, coronary artery disease, cerebrovascular accident, and myocardial infarction. Results: Fat‐to‐Bone ratio and BMI were both significantly associated with hypertension, diabetes, hyperlipidemia, obstructive sleep apnea, and osteoarthritis (P < .05). However, only Fat/Bone Ratio is associated with atherosclerosis (p = 0.02), coronary artery disease (p = 0.001), myocardial infarction (p = 0.002), and peripheral vascular disease (p = 0.01); BMI is not associated with these comorbidities (p = 0.90, 0.42, 0.25, and 0.50, respectively). Conclusions and Relevance: Findings suggest that Fat/Bone Ratio is an improved measure of obesity as compared to BMI.
2
Goon, DT, AL Toriola, BS Shaw, and LO Amusa. "Centripetal fat patterning in South African children." Pakistan Journal of Medical Science, 2010. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000435.
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Objectives: The waist-to-stature ratio (WSR) is newly developed index, proposed to be of greater value as a simple anthropometric indicator, for predicting abdominal obesity and
related cardiovascular co-morbidities in adults and children. This study examined age and gender differences in waist-to-stature (WSR) as measure of centripetal fat patterning in a sample of children in Pretoria, South Africa.
3
Shiwlochan, Amrita G. "Prenatal androgens and visceral fat." Honors in the Major Thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1327.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Sciences
Anthropology
4
Archilla, Leslie Lumari. "Evaluation of a Maltodextrin Gel as a Partial Replacement for Fat in a High-Ratio White-Layer Cake Formulation." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/9857.
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The performance of a maltodextrin gel as a replacement (25, 50, 75, and 100%) for shortening along with high-fructose corn syrup-90 (HFCS-90), adjusted for sweetness in each treatment, were evaluated in a high-ratio white-layer cake formulation. Two controls were used to compare to fat-replaced cakes: control A (100% fat with 100% sucrose) and control B (100% fat with 50% sucrose/50% HFCS-90), which closely matched the sugar system of the fat-replaced cakes. Objective tests indicated that treatments D (50%), E (75%), and F (100%) had significantly higher (P<0.05) batter specific gravity values compared to both controls. Batter specific gravity, however, only significantly decreased (P<0.05) the volume of treatment F. Crust and crumb L and b values, indicated that control B produced a dark crust (P<0.05) with a light crumb (P<0.05), while treatment E produced a light crust (P<0.05) and treatment F a darker crumb (P<0.05). Treatment F produced a firm cake (P<0.05) with significantly (P<0.05) high percent moisture. Overall, no significant differences (Pâ⠰¥0.05) in water activity were found among treatments over time; in contrast, degree of staling significantly increased (P<0.05) over time for all treatments. Sensory results indicated that treatment F produced a significantly (P<0.05) moister, shorter, less adhesive and cohesive cake. Tenderness and sweetness scores indicated that treatments E and F were significantly (P<0.05) tougher and less sweet, respectively, when compared to the other treatments. Results from physical and sensory tests indicated that the combination of a maltodextrin gel and HFCS-90, up to 75% shortening replacement, resulted in satisfactory cakes.Master of Science
5
Gordon, Michelle A. "Short-term effects of altering the dietary carbohydrate to fat ratio on circulating leptin and satiety in women." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060522.095117/index.html.
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Webb, Lisa. "Smoking in the age of obesity : an investigation of secular trends in body fat and cigarette smoking." Thesis, Nordic School of Public Health NHV, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:norden:org:diva-3140.
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Objectives: In recent decades, obesity reached epidemic proportions in western countries, while cigarette smoking decreased. Traditionally, smoking is associated with lower relative weight (body mass index, BMI) but high abdominal obesity (waist-hip ratio, WHR). However, several recent studies suggest that BMI is higher among today’s smokers compared with non-smokers. Therefore, the present study examined whether the relationship between smoking and each of the body measures, BMI and WHR, has changed over time. Material and Methods: Data were collected from 5907 male and female residents of Gothenburg, Sweden, aged 25-65 years, and drawn randomly in four sequential cross-sections (1985, 1990, 1995, 2002) from the city’s population register. The study used general linear models to test trends over time, and adjusted all differences for age. Results: The data reported here showed higher WHR in both male and female smokers compared with non-smokers. BMI was lower in female smokers compared with female non-smokers, but did not differ significantly between male smokers and male non-smokers. Among female participants, differences in WHR between smokers and non-smokers increased significantly throughout the study. Although male participants showed a similar tendency, the differences were not significant. Adjustment for educational level did not affect the results. Conclusions: WHR was higher among smokers compared with non-smokers; this difference increased over time. Thus, concern for obesity does not provide a valid reason to continue smoking; on the contrary, it may be a reason to quit.ISBN 978-91-86739-06-5
7
Baker, Erin R. "The Impact of Adiposity on Estrone, Estradiol, Testosterone and Sex Hormone Binding Globulin in Peripubertal Females." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282577554.
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Choi, Derrick L. "The role of orexin in reward-based feeding behaviors." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1299854919.
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Dahlem, DeAnna Kay. "RELATIONSHIP BETWEEN PERCENT BODY FAT AS DETERMINED BY BIOELECTRICAL IMPEDANCE ANALYSIS AND WAIST-TO-HIP RATIO IN CHILDREN AGES 7 TO 9 YEARS." MSSTATE, 2006. http://sun.library.msstate.edu/ETD-db/theses/available/etd-06022006-222016/.
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The objective of the study was to identify the relationship between percent body fat (%BF) and waist-to-hip ratio (WHR) in children ages 7 to 9 years. The sample (n=171) was divided into four groups. Bioelectrical impedance analysis was used to estimate %BF. Significant positive correlations were observed between WHR and %BF for black females (r = 0.48), white females (r = 0.66), black males (r = 0.34), and white males (r = 0.55). Although the correlations differed between groups, the amount of variation between the two variables was not significantly different between groups other than black females. Least squares means was used to estimate %BF using an average WHR (.85). Black females had higher %BF than other groups. Percent body fat cannot be fully explained by WHR (r2 = 0.32). Results show a relationship between %BF and WHR, yet predicting %BF from a given WHR may be difficult.
10
Ratko, Mijatović. "Reproduktivne performanse krava sa različitim odnosom sadržaja masti i proteina u mlijeku do uspostavljanja gravidnosti." Phd thesis, Univerzitet u Novom Sadu, Poljoprivredni fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=90011&source=NDLTD&language=en.
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Cilj istraživanja bio je da se ustanovi povezanost energetskog statusa krava u postpartalnom periodu, iskazanog
kroz vrijednost odnosa mliječna mast: proteini, i parametara reproduktivne efikasnosti. Istraživanje je sprovedeno
na ukupno 350 oteljenih krava holštajn rase (121 prvotelka, 115 drugotelki i 114 krava koje su se telile tri i više
puta), smještenih na farmi mliječnih krava industrijskog tipa, u slobodnom sistemu držanja i hranjenih uobičajenim
obrocima za datu rasu goveda, proizvodnu kategoriju, stadijum laktacije i period godine. Sve ispitane krave, bez
obzira na paritet, podijeljene su u odnosu na stadijum laktacije (15-45 dana, 46-75 dana, 76-105 dana i 106-135
dana), a u okviru svakog njih formirane su podgrupe u odnosu na vrijednost odnosa mliječna mast : proteini (OMP
< 1,0 , OMP 1,0-1,3 i OMP > 1,3). Podjela krava unutar svakog pariteta (prvotelke, drugotelke, krave sa tri i više
teljenja), izvršena je na osnovu trajanja servis perioda (SP do 60 dana, SP 61-90 dana, SP 91-135 dana). Praćeni su
sljedeći reproduktivni parametri: period do prvog vještačkog osjemenjavanja (dani), trajanje servis perioda (dani),
trajanje perioda od prvog vještačkog osjemenjavanja do uspostavljanja steonosti (dani), indeks osjemenjavanja,
trajanje graviditeta (dani) i trajanje međutelidbenog intervala (dani). Uzorci mlijeka uzimani su u okviru
uzorkovanja za potrebe selekcijske službe. U uzorcima mlijeka su određene koncentracije mliječne masti i proteina,
te je izračunat njihov međusobni odnos (OMP). Podaci su statistički obrađeni metodama deskriptivne statistike, a
značajnost razlika između grupa testirana je t-testom. Pored numeričkih vrijednosti za ispitane parametre, za sve
ispitane grupe krava u radu je dat i grafički prikaz odnosa mliječne masti i proteina. U prilogu je dat pregled
vrijednosti parametara deskriptivne statistike za ispitane parametre za sve ispitane grupe krava. U svakoj od
ispitanih grupa krava, bez obzira na način podjele, ustanovljen je veliki procenat krava sa vrijednostima OMP izvan
fizioloških okvira, bilo da se radi o povišenim ili sniženim vrijednostima. Zbirni podaci za svaku od ispitanih grupa
krava, prikazani na grafikonima, ukazuju na generalno nepovoljan metabolički status krava na ispitanoj farmi i
visok procenat subkliničkih poremećaja zdravlja, prije svega subkliničke forme ketoze, udružene sa različitim
stepenom zamašćenja jetre, što se odražava i na vrijednosti reproduktivnih parametara. Podaci o trajanju perioda do
prvog vještačkog osjemenjavanja u svim ispitanim grupama krava, bez obzira na način grupisanja, ukazuju na visok
stepen varijacija, kao rezultat različite sposobnosti krava prilagode nepovoljnom bilansu energije,. Energetski status
grla je, preko različitih mehanizama opisanih u radu, uticao i na trajanje perioda od prvog do uspješnog vještačkog
osjemenjavanja i servis perioda, kao i na vrijednost indeksa osjemenjavanja u svim ispitanim grupama krava, pri
čemu su grla sa povoljnijim energetskim statusom generalno imala povoljnije vrijednosti ovih parametara. Pored
energetskog statusa, podaci prikazani u radu govore i o neadekvatnoj organizaciji otkrivanja estrusa, kao
značajnom ograničavajućem faktoru za postizanje optimalnih reproduktivnih rezultata na ispitanoj farmi. Prosječno
trajanje graviditeta u svim ispitanim grupama krava kretalo se u okvirima za datu vrstu i rasu, te je stoga trajanje
međutelidbenog intervala bilo primarno uslovljeno trajanjem servis perioda.
Rezultati ovog istraživanja ukazuju da postoji pozitivna veza između energetskog statusa krava, iskazanog kroz
vrijednosti odnosa mliječna mast : proteini, i reproduktivnih parametara, pri čemu prilikom tumačenja dobijenih
rezultata treba imati u vidu i niz dodatnih faktora, kao što su rasa, visina dnevne proizvodnje mlijeka, sastav i
konzumacija obroka, ambijentalni uslovi i slično. Odabir grla na kojima je istraživanje sprovedeno uslovio je da se reproduktivni rezultati svih ispitanih grupa krava kreću u okvirima koji se u literaturi navode kao zadovoljavajući,
iako su njihove vrijednosti na nivou cijele farme značajno nepovoljnije. Rezultati ovog istraživanja ukazuju na
značajan potencijal primijenjene metode za rano otkrivanje grla sa predispozicijom za nastanak poremećaja
zdravlja i reprodukcije, te pravovremeno preduzimanje dijagnostičkih i terapijskih procedura sa ciljem da se
posljedice negativnog bilansa energije tokom perioda rane laktacije ublaže, i time omogući postizanje adekvatnih
reproduktivnih rezultata.
11
Peters, Andreas Ph D. Massachusetts Institute of Technology. "Ultra-short nacelles for low fan pressure ratio propulsors." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87128.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 205-216).
This thesis addresses the uncharted inlet and nacelle design space for low pressure ratio fans for advanced aeroengines. A key feature in low fan pressure ratio (FPR) propulsors with short inlets and nacelles is the increased coupling between fan and inlet. The thesis presents an integrated fan-nacelle design framework, combining a spline-based tool for the denition of inlet and nacelle surfaces with a fast and reliable body-force-based approach for the fan rotor and stator blade rows. The new capability captures the inlet-fan and fan-exhaust interactions and the ow distortion at the fan face and enables the parametric exploration of the short-inlet design territory. The interaction of the rotor with a region of high streamwise Mach number at the fan face is identied as the key aerodynamic mechanism limiting the design of short inlets. The local increase in streamwise Mach number is due to ow acceleration along the inlet internal surface coupled with a reduction in eective ow area. For a candidate short-inlet design with inlet length to fan diameter ratio L=D = 0:19, the streamwise Mach number at the fan face near the shroud increases by up to 0:16 at cruise and by up to 0:36 at o-design conditions relative to a long-inlet baseline propulsor with L=D = 0:5. As a consequence, the rotor locally operates close to choke, resulting in fan eciency penalties of up to 1:6% at cruise and 3:9% at o-design. For inlets with L=D < 0:25, the benet from reduced nacelle drag is offset by the reduction in fan eciency, resulting in propulsive eciency penalties. Based on a parametric inlet study, the recommended inlet L=D for engine propulsive eciency benefits is suggested to be between 0:25 and 0:4. A candidate design with L=D = 0:25 maintains the cruise propulsive efficiency of the baseline case without jeopardizing fan and LPC stability at o-design conditions. On the aircraft system level, fuel burn benefits are conjectured to be feasible due to the reductions in nacelle weight and drag compared to an aircraft powered by the long-inlet baseline propulsor.
by Andreas Peters.
Ph. D.
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Sun, Luotao. "A fast radio transmitter identification system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0003/MQ41785.pdf.
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Cruces, Marilyn [Verfasser]. "The Transient Radio Sky: Pulsars and Fast Radio Bursts / Marilyn Cruces." Bonn : Universitäts- und Landesbibliothek Bonn, 2021. http://nbn-resolving.de/urn:nbn:de:hbz:5-63345.
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Cheraghi, Parisa. "Fast and accurate spectrum sensing low signal noise ratio environment." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.581799.
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Opportunistic Spectrum Access (OSA) [1] promises tremendous gain in improving spectral efficiency. The main objective of OSA is to offer the ability of identifying and exploiting the under-utilised spectrum in an instantaneous manner in a wireless device, without any user intrusion. Hence, the initial requirement of any OSA device is the ability to perform spectrum sensing. Local narrow-band spectrum sensing has been quite well investigated in the literature. However, it is realised that existing schemes can hardly meet the requirements of a fast and accurate spectrum sensing particulariy in very low signal-to-noise-ratio (SNR) range without introducing high complexity to the system. Furthermore, increase in the spectrum utilisation calls for spectrum sensing techniques that adopt an architecture to simultaneously search over multiple frequency sub-bands at a time. However, the literature of sub-band spectrum sensing is rather limited at this time. The main contributions of this thesis is two-fold: First a clusterd-based differential energy detection for local sensing of multi- carrier based system is proposed. The proposed approach can form fast and reliable decision of spectrum availability even in very low SNR environment. The underlying initiative of the proposed scheme is applying order statistics on the clustered differential Energy Spectral Density (ESD) in order to exploit the channel frequency diversity inherent in high data-rate communications. Second contribution is three-fold: 1) re-defining the objective of the sub- band level spectrum sensing device to a model estimator, 2) deriving the optimal model selection estimator for sub-band level spectrum sensing for fixed and variable number of users along with a sub-optimal solution based on Bayesian statistical modelling and 3) proposing a practical model selection estimator with relaxed sample size constraint and limited system knowledge for sub-band spectrum sensing applications in Orthogonal Frequency-Division Multiple Access (OFDMA) systems. The result obtained showed that through exploitation of the channel frequency selectivity the performance of the stat-of-the-art spectrum sensing techniques can be significantly improved. Furthermore, by modelling the sub-band level spectrum sensing through model estimation allows for new spectrum sensing approach. It was proved both analytically and through simulations that the proposed approach have significantly extended to state-of-the-art spectrum sensing. Key words: Differential, energy detection, low signal-to- noise ratio (SNR), multi- carrier, opportunistic spectrum access, spectrum sensing.
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Khalaf, Sadi Shalan. "THE USE OF CALCIUM TREATED ANIMAL FAT IN THE RATION OF DAIRY COWS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275261.
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Lie, Chin Cheong Patrick. "Iterative algorithms for fast, signal-to-noise ratio insensitive image restoration." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63767.
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Hu, Stanley 1978. "Fast failure detection in distributed software radio applications." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86710.
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Hugo, Benjamin. "Fast online predictive compression of radio astronomy data." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/21225.
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This report investigates the fast, lossless compression of 32-bit single precision
floating-point values. High speed compression is critical in the context of
the MeerKAT radio telescope currently under construction in Southern Africa and
Australia, which will produce data at rates up to 1 Petabyte every 20 seconds.
The compression technique being investigated is based on predictive compression,
which has proven successful at achieving high-speed compression in previous research.
Several different predictive techniques (which includes polynomial extrapolation),
along with CPU- and GPU-based parallelization approaches are discussed.
The implementation successfully achieves throughput rates in excess of 6 GiB/s
for compression and much higher rates for decompression using a 64-core AMD
Opteron machine, achieving file-size reductions of, on average 9%. Furthermore
the results of concurrent investigations into block-based parallel Huffman encoding
and Zero-length Encoding are compared to the predictive scheme and it was found
that the predictive scheme obtains approximately 4%-5% better compression ratios
than the Zero-Length Encoder and is 25 times faster than Huffman encoding on
an Intel Xeon E5 processor. The scheme may be well-suited to address the large
network bandwidth requirements of the MeerKAT project.
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Carvalho, Maria Odete Ximenes. "Idade e crescimento do robalo-flecha, Centropomus undecimalis (BLOCH, 1792) e robalo-peva, Centropomus parallelus (POEY, 1860) (OSTEICHTHYES: CENTROPOMIDAE), no Sudeste do Brasil." http://www.teses.ufc.br/, 2006. http://www.repositorio.ufc.br/handle/riufc/1312.
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CARVALHO, Maria Odete Ximenes. Idade e crescimento do robalo-flecha, Centropomus undecimalis (BLOCH, 1792) e robalo-peva, Centropomus parallelus (POEY, 1860) (OSTEICHTHYES: CENTROPOMIDAE), no Sudeste do Brasil/. 2006. 71 f. Dissertação (Mestrado em Ciências Marinhas Tropicais) - Instituto de Ciências do Mar, Universidade Federal do Ceará, Fortaleza, 2006.Submitted by Debora Oliveira (deby_borboletinha@hotmail.com) on 2011-11-25T16:36:41Z No. of bitstreams: 1 2006_dis_moxcarvalho.pdf: 1511497 bytes, checksum: 45c7855f6d93f5c86bd7cd25ab90fe3b (MD5)
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The common snook, Centropomus umdecimalis, and the fat snook, Centropomus parallelus, are two species that dwell on estuarine and costal marine environments along the North, Northeast and South Brazil, hence with great potential for mariculture. The estimation of age and growth parameters, the primary objective of this paper, should supply the necessary information to evaluate the cost/benefit ratio for the development of marine fish farms, especially as to feeding efficiency in promoting the enhancement of growth rates in comparison to that of wild populations. The databank was obtained by means of sampling of the landings made at the São Pedro fishmarket, in Niterói, Rio de Janeiro State, by the commercial fleet of liners which fish for pelagic resources off Cabo Frio’s coast (23oS) The collected material was comprised of 264 specimens, 130 of C. undecimalis and 134 of C. parallelus, in the period from June, 1999 through June, 2000. From a site below the pectoral fin scales were drawn for age and growth studies to be performed by means of the identification of age rings and measurement of growth bands. Total lengths of the sampled fish were in the range of 33.1 – 78.9 cm (C. undecimalis) and 29.5 – 57.3 cm (C. parallelus). The basic assumptions on the dependence of fish size on scale size, and the periodicity in age rings formation were investigated by regression equations and monthly variations in the scale’s marginal increment, respectively. The parameters of the growth equation, namely asymptotic length, growth coefficient and theoretical age at birth, and growth performance index as well were estimated. The natural mortality coefficient (M) was calculated in order to make up the M/K ratio. Statistical analyses were used in order to compare the growth rate between common snook and fat snook through Student’s t test, and to assess the significance of age changes between pairs of adjoining months through Kruskal-Wallis’ H test. The drawn results may be summarized as follows: (a) the assumption of a regression of scale length on fish length was met; (b) the “birth dates” of common snook and fat snook correspond with April-June and August-October monthly periods; (c) the age and growth parameters for common snook were: L = 101. 1 cm, W = 11.4 kg, K = 0.112, t0 = - 2.59 yr., tmax = 29.3 yr. and f’ = 3.058; (d) the age and growth parameters for fat snook were: L = 67.9, W = 3.6 kg, K = 0.187, t0 = - 2.48 yr., tmax = 18.6 yr. and f’ = 2.936; (e) the fat snook reaches a smaller size but grows quicker than the common snook; (f) the natural mortality coefficient was estimated at M = 0.259 (C. undecimalis) e M = 0.406 (C. parallelus), entailing respective values of M/K = 2.312 and M/K = 2.171, which classify those species into the fourth trophic level; (g) The growth performance indices indicate the adoption of a strategy consistent with that assumed by mean- and large-sized predatory species.
O robalo-flecha, Centropomus umdecimalis, e robalo-peva, Centropomus parallelus, são duas spécies habitantes de ambientes estuarino e costeiro marinho ao longo das regiões Norte, Nordeste e Sudeste do Brasil portanto, com grande potencialidade para a maricultura. A estimação dos parâmetros de crescimento, objeto principal deste trabalho, fornecerá as informações necessárias para se avaliar a relação custo/benefício na implantação de projetos de cultivo, principalmente quanto à eficiência alimentar sobre a taxa de crescimento registrada por populações naturais. Os dados básicos foram obtidos por amostragem dos desembarques de pescado no Mercado de São Pedro (Niterói, Estado do Rio de Janeiro), efetuados pela frota comercial de barcos linheiros que atuam ao longo da costa de Cabo Frio (23º S). O material coletado consiste de 264 exemplares, sendo 130 de C. undecimalis e 134 de C. parallelus, no período entre junho de 1999 e junho de 2000. Destes foram retiradas escamas para os estudo da idade e crescimento, por meio da identificação dos anéis etários e mediação das zonas de crescimento. As amplitudes de variação do comprimento total foram 33,1 – 78,9 cm (C. undecimalis), e 29,5 – 57,3 cm (C. parallelus). As premissas básicas sobre proporcionalidade nos padrões de crescimento da escama e do peixe, e sobre a periodicidade na formação dos anéis etários, foram avaliadas por meio da análise de regressão e variação mensal no Incremento Marginal, respectivamente. Os parâmetros de crescimento, comprimento máximo teórico, coeficiente de crescimento, e idade inicial aparente, bem como o índice de desempenho do crescimento, foram estimados. O coeficiente de mortalidade natural (M) foi também estimado para fazer parte da razão M/K. Análises estatísticas foram empregadas para se comparar o padrão de crescimento entre as duas espécies (teste t) e a significância da mudança de idade em intervalos mensais (teste H, de Kruskal-Wallis). Os resultados obtidos estão resumidos nos seguintes itens: (a) Confirmou-se a premissa de proporcionalidade isométrica entre os comprimentos do peixe e da escama; (b) as “datas de aniversário” do robaloflecha e do robalo-peva correspondem aos períodos mensais de abril-junho e agosto-outubro, respectivamente; (c) os parâmetros de idade e crescimento estimados para o robalo-flecha foram: L = 101, 1 cm, W = 11,4 kg, K = 0,112, t0 = - 2,59 ano, tmax = 29,3 anos e f’ = 3,058; (d) os parâmetros de idade e crescimento estimados para o robalo-peva foram: L = 67,9, W = 3,6 kg, K = 0,187, t0 = - 2,48 ano, tmax = 18,6 anos e f’ = 2,936; (e) O robalo-peva atinge um menor tamanho mais tem taxa de crescimento mais rápida do que o robalo-flecha; (f) o coeficiente de mortalidade natural foi estimado como M = 0,259 (C. undecimalis) e M = 0,406 (C. parallelus), com os respectivos valores de M/K = 2,312 e M/K = 2,171, que classificam estas espécies como pertencentes ao 4º nível trófico; (g) Os valores do coeficiente de desempenho (f’) confirmam a adoção de uma estratégia de crescimento compatível com espécies predadoras de médio e grande portes.
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Monogioudis, Pantelis Nikolaos. "Near-far resistant detection for CDMA personal communication systems." Thesis, University of Surrey, 1994. http://epubs.surrey.ac.uk/844251/.
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The growth of Personal Communications, the keyword of the 90s, has already the signs of a technological revolution. The foundations of this revolution are currently set through the standardization of the Universal Mobile Telecommunication System (UMTS), a communication system with synergistic terrestrial and satellite segments. The main characteristic of the UMTS radio interface, is the provision of ISDN services. Services with higher than voice data rates require more spectrum, thus techniques that utilize spectrum as efficiently as possible are currently at the forefront of the research community interests. Two of the most spectrally efficient multiple access technologies, namely. Code Division Multiple Access (CDMA) and Time Division Multiple Access (TDMA) concentrate the efforts of the European telecommunity. This thesis addresses problems and. proposes solutions for CDMA systems that must comply with the UMTS requirements. Prompted by Viterbi's call for further extending the potential of CDMA through signal processing at the receiving end, we propose new Minimum Mean Square Error receiver architectures. MMSE detection schemes offer significant advantages compared to the conventional correlation based receivers as they are NEar FAr Resistant (NEFAR) over a wide range of interfering power levels. The NEFAR characteristic of these detectors reduces considerably the requirements of the power control loops currently found in commercial CDMA systems. MMSE detectors are also found, to have significant performance gains over other well established interference cancellation techniques like the decorrelating detector, especially in heavily loaded system conditions. The implementation architecture of MMSE receivers can be either Multiple-Input Multiple Output (MIMO) or Single-Input Single-Output. The later offers not only complexity that is comparable to the conventional detector, but also has the inherent advantage of employing adaptive algorithms which can be used to provide both the dispreading and the interference cancellation function, without the knowledge of the codes of interfering users. Furthermore, in multipath fading channels, adaptive MMSE detectors can exploit the multipath diversity acting as RAKE combiners. The later ability is distinctive to MMSE based receivers, and it is achieved in an autonomous fashion, without the knowledge of the multipath intensity profile. The communicator achieves its performance objectives by the synergy of the signal processor and the channel decoder. According to the propositions of this thesis, the form of the signal processor needs to be changed, in order to exploit the horizons of spread spectrum signaling. However, maximum likelihood channel decoding algorithms need not change. It is the way that these algorithms are utilized that needs to be revis ed. In this respect, we identify three major utilization scenarios and an attempt is made to quantify which of the three best matches the requirements of a UMTS oriented CDMA radio interface. Based on our findings, channel coding can be used as a mapping technique from the information bit to a more ''intelligent" chip, matching the ''intelligence" of the signal processor.
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Martins, Susana Isabel Vargas. "New insights into biological effects of conjugated linoleic acid and saturated fats in body fat composition, obesity and related disorders: experimental studies in normal-weight Wistar and obese Zucker rats." Doctoral thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2010. http://hdl.handle.net/10400.5/1770.
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Tese de Doutoramento em Ciência e Tecnologia AnimalThe daily intake of conjugated linoleic acid (CLA) isomers by humans, through diet and supplementation, and the controversial effects of these compounds in human health, were the main motivation for the elaboration of this thesis. Firstly, the present work intended to estimate the daily CLA ingestion by the Portuguese population. Secondly, the biological effects of CLA were exploited using two distinct animal models, normal-weight (Wistar rat) and genetically fat (obese Zucker rat), in combination with saturated fat based diets. The estimative of total CLA intake for the Portuguese population was 73.70 mg/day. The cis(c)9,trans(t)11 and t7,c9 were the most prevalent CLA isomers, with, respectively, 76.10 and 12.56% of the total CLA intake value. Concerning the animal trials, CLA in conjugation with saturated fats revealed beneficial but also deleterious biological effects. In the normal-weight Wistar rat fed a palm oil based diet, the administration of c9,t11 CLA isomer increased the serum triacylglycerols and the size of adipocytes from epididymal and retroperitoneal fat depots. In addition, a CLA mixture of c9,t11 and t10,c12 isomers increased the glycerol membrane permeability of kidney proximal tubules, which may indicate an improvement of glycerol reabsorption pathway. In the obese Zucker rat, CLA (as a mixture) induced changes in fatty acid profile of liver, muscle and adipose depots. CLA supplemented with a vegetable saturated fat diet seemed to promote a more beneficial adipokine serum profile and an alleviation of hepatic steatosis. In contrast, adverse effects of CLA were observed with hypercholesterolaemia promotion. Regardless CLA, the ovine fat diets worsened the insulin resistance and increased the pro-inflammatory serum cytokines. In the liver, different levels of cell death and apoptotic pathways were modulated by CLA, depending on the type of saturated fat present in the diet. The most striking result of this study was that CLA was not able to promote fat loss in both experimental models. Moreover, new mechanisms of CLA action were disclosed in this work, which reinforce the need to further investigate this compound.
RESUMO - Efeitos biológicos do ácido linoleico conjugado e de gorduras saturadas na composição da gordura corporal, na obesidade e patologias associadas: estudos experimentais em ratos Wistar e Zucker obesos - A ingestão diária de isómeros do ácido linoleico conjugado (CLA), através da dieta e da sua suplementação, bem como, os efeitos controversos destes compostos na saúde humana, constituíram a principal motivação para a elaboração desta tese. Numa primeira fase, o trabalho pretendeu estimar a ingestão diária de CLA pela população Portuguesa. Posteriormente, foram avaliados os efeitos biológicos do CLA quando suplementado a dietas à base de gordura saturada. Para tal, recorreu-se a dois modelos animais distintos, o rato Wistar e o rato Zucker (geneticamente obeso). A ingestão média total de CLA pela população Portuguesa foi estimada em 73.70 mg/dia. Os isómeros do CLA mais representativos foram o cis(c)9,trans(t)11 e o t7,c9, correspondendo, respectivamente, a 76.10 e 12.56% do total de CLA ingerido. Quanto aos estudos in vivo, o CLA revelou efeitos biológicos tanto benéficos como prejudiciais. No modelo Wistar alimentado com dieta à base de óleo de palma, a administração do isómero do CLA c9,t11 elevou os níveis de triacilgliceróis no soro, bem como, o tamanho dos adipócitos das gorduras epididimal e retroperitoneal. Adicionalmente, a mistura de isómeros do CLA (c9,t11 e t10,c12) aumentou a permeabilidade membranar ao glicerol no túbulo proximal do rim, sugerindo uma melhoria no processo de reabsorção desta molécula. No modelo Zucker, o CLA (como mistura de isómeros) induziu alterações no perfil dos ácidos gordos do fígado, músculo e gorduras epididimal e retroperitoneal. O CLA administrado com óleo de palma promoveu um perfil de adipocinas no soro mais benéfico e melhorou a esteatose hepática. Em contraste, a suplementação com CLA apresentou um efeito hipercolesterolémico. Independentemente do CLA, a dieta rica em gordura de ovinos agravou a resistência à insulina e aumentou as adipocinas pró-inflamatórias no soro. No fígado, diferentes níveis de morte celular e vias apoptóticas foram modeladas pelo CLA em função do tipo de gordura presente na dieta. É de salientar que não se observaram efeitos anti-adipogénicos do CLA em nenhum dos dois modelos animais. Por último, esta tese contribuiu para a descoberta de novos mecanismos de acção dos isómeros do CLA, reforçando a necessidade de continuar a estudar estes compostos.
This work was funded by Fundação para a Ciência e a Tecnologia (FCT) through the individual fellowship SFRH/BD/22566/2006 and co-financed by the grant POCTI/44750/2002
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Hilmarsson, Guðjón Henning [Verfasser]. "Targeted Fast Radio Burst Searches with the Efflesberg 100-m Radio Telescope / Guðjón Henning Hilmarsson." Bonn : Universitäts- und Landesbibliothek Bonn, 2021. http://d-nb.info/1231911115/34.
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Yan, Raymond T. H. "Fast radio-frequency current density imaging with spiral acquisition." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28857.pdf.
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Ishii, T. Koryu. "Sensing of Irregularities on Fast Moving Surfaces by Microwaves and Millimeterwaves." International Foundation for Telemetering, 1988. http://hdl.handle.net/10150/615034.
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International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, NevadaFine cracks and irregularities on a fast moving conducting surface were detected by the use of microwave and millimeter wave radio responder techniques. The interrogation angle was restricted to an oblique incidence angle less than ±0.5 degree from the surface. The fast moving conducting surface was surrounded by both fast moving and stationary reflective conducting structures. Experimental methods and results from a fine crack 0.1 mm wide, 0.9 mm deep, and 25 mm long on a conducting surface travelling with a speed of 20.23 m/s and measured at 10.525 GH(z) and 73 GH(z) are presented. The reflection-type microwave radio responder consisted of a 10.525 GH(z) 50 mW Gunn diode cw transmitter, a circulator, and a horn antenna used as the interrogator. The receiver in the same responder consisted of the same horn antenna, the circulator and detector diode. The detector diode output was observed with a Norland 3106R digital memory oscilloscope. A reflex kylstron VA 250 was used as the transmitter signal source for the millimeter wave responder. There was a distinct difference between the responder output patterns with uncracked and cracked surfaces. It is therefore possible to use this type of responder for hair-line crack detection of fast moving conducting surfaces. It was also found that this type of radio responder can detect the surface irregularity even before the hairline crack actually occurs.
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Perrin, Martin. "Performance model of a very high bypass ratio counter rotating turbo fan engine." Thesis, KTH, Kraft- och värmeteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92126.
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Nowadays Snecma focuses on new engine architectures in order to meet the future demands in civil aviation. One of these considered concepts is aircrafts powered by counter rotating fan engines which aim at tackling both noise and polluting emissions. A powerful way to reduce the perceived noise is to reduce the fan rotating speeds, which requires to lower fan pressure ratio. This thesis continues a study on an innovative counter rotating fan architecture carried out by Snecma from 2005 to 2010 for VITAL (European Commission funded project). It is a way to meet the noise target while maintaining acceptable engine dimensions and matching installation constraints since each fan has a smaller diameter than the current ones, and an individual low pressure ratio. Therefore the drag is decreased and less fuel is burnt. In order to fulfill these ambitious objectives, the first step of this thesis is to use the code of the VITAL model developed with Janus (Snecma in-house code) in order to create a new code for the PROOSIS software. When modeling two counter rotating fans, the key point is to take into account the influence from the first stage on the second one. Since the aft fan “sees” a perturbed flow by the inlet fan wake, its characteristic map is not the usual one anymore. One major challenge was the new design of a two separated flow and three-spool counter rotating engine driven by a gearbox which meets the very high bypass ratio target. The model finally turned out to be operational for a relevant set of initialization parameters and thus makes now possible more accurate studies on counter rotating turbofan engines in the R&T unit.
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Zhou, Jianmin. "Evaluation of different types of fats for use in high-ratio layer cakes." Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/2508.
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Karalazos, Vasileios. "Sustainable alternatives to fish meal and fish oil in fish nutrition : effects on growth, tissue fatty acid composition and lipid metabolism." Thesis, University of Stirling, 2007. http://hdl.handle.net/1893/220.
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Traditionally, fish meal (FM) and fish oil (FO) have been used extensively in aquafeeds, mainly due to their excellent nutritional properties. However, various reasons dictate the use of sustainable alternatives and the reduction of the dependence on these commodities in fish feeds. Hence, the aim of the present thesis was to investigate the effects of the replacement of FM and FO with two vegetable oils (VO) and an oilseed meal on the growth performance, feed utilization, nutrient and fatty acids (FA) digestibility and tissue FA composition and metabolism in three commercially important European fish species. Specifically, in Experiment I crude palm oil (PO) was used to replace FO in diets for rainbow trout. In Experiments II and III FO was replaced with rapeseed oil (RO) in diets for Atlantic salmon at various dietary protein/lipid levels aiming also at further reductions of FM by using low protein (high lipid) diet formulations. In Experiments II and III the fish were reared at low and high water temperatures, respectively, in order to elucidate, also, the potential effects of temperature. Lastly, the effects of the replacement of FM with full fat soya meal (FFS) in Atlantic cod were investigated in Experiment IV. The results of the present thesis showed no negative effects on growth performance and feed utilization in rainbow trout when FO was replaced with PO. The dietary inclusion of RO improved the growth of Atlantic salmon, possibly, due to changes in the nutrient and FA digestibilities and FA catabolism while, the growth and feed utilization were unaffected by the dietary protein/lipid level. However, the growth of Atlantic cod was affected negatively by the replacement of FM with FFS. The proximate composition of the fish whole body was in most cases unaffected by dietary treatments. The changes in dietary formulations affected the dietary FA compositions and resulted in significant changes in the fish tissue FA compositions. It was clearly shown that the fish tissue total lipid FA composition reflects the FA composition of the diet, although specific FA were selectively utilized or retained in the tissues by the fish. These may have serious implications not only for fish metabolism and growth but also for the quality of the final product, especially in terms of possible reductions of n-3 HUFA.
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Petrolati, Andrea. "Fate of nitrogen/trace metals species during combustion and gasification of biomass." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/7011.
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This thesis focused on the fate of nitrogen and trace metals species from combustion and gasification of biomass. The effect of process parameters on the release of these species during pilot-scale combustion and gasification of biomass was investigated and the information used to identify methods for the reduction of these species. The investigation focused on Miscanthus and Dried distillers’ grains with solubles (DDGS). The pilot-scale test rigs used were a fluidised-bed combustor and a fixed-bed downdraft gasifier. The two fuels were analysed by means of proximate, ultimate and ash analysis. The process parameters monitored were temperatures, gas flow, gas composition and ash composition and the process parameters studied are bed temperature and equivalence ratio. The different nitrogen content of the two fuels plays an important role in the emission. Both bed temperature and air to fuel ratio have demonstrated to have an important influence in the release of nitrogen oxides in combustion and ammonia in gasification, therefore they can be used to mitigate the emission of these species in the flue gas. Both processes are affected by the high alkali metals content of the fuels for the tendency to form low melting composites. Differences have been highlighted in the metal distribution between combustion and gasification. The different nitrogen and ash content of the two fuels make the results of the present thesis applicable to predict the behaviour of other biomass fuels according to the fuel characteristics. The scale of the tests performed allowed highlighting which methods can be used to control the emission of nitrogen and trace metal species. Moreover, the investigation highlighted major drawbacks in the use of biomass fuels in both fluidised bed and fixed bed technology due to ash properties.
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Wijayasuriya, Shridhir Sariputta Hansa. "Alleviation of near-far effects in DS-CDMA mobile radio." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386073.
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Gordin, Jake E. B. "Cosmic string cusps and their application to fast radio bursts." Master's thesis, Faculty of Science, 2018. http://hdl.handle.net/11427/29983.
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This thesis concerns observational characteristics of two theoretical aspects of cosmic strings. The first is relativistic modification of cusps. Nambu-Goto strings generically develop cusps, regions of the string which emit coherent electromagnetic radiation when they decay. We point out that consideration of relativistic effects in the rest frame of the string cusp substantially reduces the cusp length, and therefore modifies the normally assumed power, rate, and time scale of any radiation bursts. The second is consideration of wiggly cosmic strings. Simulations imply a distribution of strings in an expanding universe develop small-scale structure called wiggles. We extend on a wiggly Polyakov formalism and show that wiggles prohibit cusp formation (barring ad-hoc fine tuning of initial conditions). We discuss these theoretical results in the context of using strings to explain fast radio bursts (FRBs). Cusp decay is a possible mechanism for sourcing FRBs. We show, however, that (1) consideration of relativistic effect leads to incompatibility with FRB data, and (2) the absence of cusps from “realistic” cosmic strings casts further doubt on the possibility of detecting cosmic strings via electromagnetic signatures.
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Platts, Emma. "Computational analysis techniques using fast radio bursts to probe astrophysics." Doctoral thesis, Faculty of Science, 2021. http://hdl.handle.net/11427/33921.
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This thesis focuses on Fast Radio Bursts (FRBs) and presents computational techniques that can be used to understand these enigmatic events and the Universe around them. Chapter 1 provides a theoretical overview of FRBs; providing a foundation for the chapters that follow. Chapter 2 details current understandings by providing a review of FRB properties and progenitor theories. In Chapter 3, we implement non-parametric techniques to measure the elusive baryonic halo of the Milky Way. We show that even with a limited data set, FRBs and an appropriate set of statistical tools can provide reasonable constraints on the dispersion measure of the Milky Way halo. Further, we expect that a modest increase in data (from fewer than 100 FRB detections to over 1000) will significantly tighten constraints, demonstrating that the technique we present may offer a valuable complement to other analyses in the near future. In Chapter 4, we study the fine time-frequency structure of the most famous FRB: FRB 121102. Here, we use autocorrelation functions to maximise the structure of 11 pulses detected with the MeerKAT radio telescope. The study is motivated by the low time-resolution of MeerKAT data, which presents a challenge to more traditional techniques. The burst profiles that are unveiled offer unique insight into the local environment of the FRB, including a possible deviation from the expected cold plasma dispersion relationship. The pulse features and their possible physical mechanisms are critically discussed in a bid to uncover the nature and origin of these transients.
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Tsai, Jr-Wei. "Searches for Radio Transients using the Long Wavelength Array." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/70886.
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We used the first station of the Long Wavelength Array (LWA) to observe giant pulses (GPs) from pulsars and search for other radio transients. Using the LWA with a bandwidth of 16 MHz at 39 MHz, we made a 24-hour observation of pulsar radio pulses from PSR B0950+08. The average pulse ux density and pulse width (dominated by "normal" pulses) are consistent with previous studies by others. Using techniques we developed for searching for radio transients, in this observation we detected 119 giant pulses (with signal-to-noise ratios 10 times larger than for the mean pulse). The giant pulses have a narrower temporal width (17.8 ms, on average) than the mean pulse (30.5 ms). Giant pulses occur at a rate of about 5.0 per hour, or 0.035% of the total number of pulse periods. The strength and rate of giant pulses is less than observed by others at ~100 MHz. The probability distribution of the cumulative pulse strength is a power law, but deviates from the Gaussian distribution of normal pulses. These results suggest PSR B0950+08 produces less frequent and weaker giant pulses at 39 MHz than at 100 MHz. We detected no other transients in this observation within a dispersion measure (DM) range from 1 to 90 pc cm³.
Furthermore, we conducted observations of giant pulses from PSR B0950+08 in a separate set of observations of 12 hours made simultaneously at 42 and 74 MHz. In these observations we detected a total of 275 at 42 MHz and a total of 465 giant pulses at 74 MHz. Giant pulses with double-peak temporal structure have a shorter peak-to-peak separation compared to the average pulse. Once again, PSR B0950+08 appears to produce less frequent and weaker giant pulses than reported at 100 MHz. Giant pulses are identified with signal-to-noise ratios 10 times larger than for the mean pulse, and the probability distribution of the cumulative pulse strength is a power law, but deviate from the Gaussian distribution of normal pulses, for both frequencies. There were only 128 giant pulses detected simultaneously at 42 and 74 MHz, which implies that more than half of them are narrow-band radio pulses. Using these observations we analyzed the effect of scattering due to the interstellar medium on pulses with signal-to-noise ratio > 7 and the average pulse using a CLEAN-based algorithm, assuming a thin-screen scattering model. The scatter-broadening time constant τ ∝ να, where ν is the observing frequency. The resulting α as calculated from pulses with signal-tonoise ratio > 7 and for the average pulses is found to be α = −1.45±0.14 and −0.14±0.03, respectively. These results indicate differences along the line of sight from a Kolmogorov spectrum for electron density uctuations. We calculated the altitude of the emission region for the pulsar using the dipolar magnetic field model. We found a similar magnitude for the emission region altitudes of normal and giant pulses. We detected no other transient pulses in a wide DM range from 1 to 4990 pc cm⁻³.
We also conducted another a 12-hour observational study of PSR B0031−07 at 38 and 74 MHz, simultaneously. Giant pulses were identified with ux densities of a factor of ≥ 90 and ≥ 80 times that of an average pulse, at 38 and 74 MHz. The cumulative pulse strength distribution follows a power law, and has a much more gradual slope than a Gaussian distribution for the normal pulses. We found 158 of the observed pulses at 38 MHz qualified as giant pulses. At 74 MHz a total of 221 of the observed pulses were giant pulses. Only 12 giant pulses were detected within the same pulse period at both 38 and 74 MHz, meaning that the majority of them are narrow-band radio pulses. No other radio transients were detected within a DM range 1 to 4990 pc cm⁻³.
We used the same data processing pipeline for observations of pulsar GPs to search within the pulsar observations for fast radio bursts (FRBs). We did not detect any nonpulsar signals with signal-to-noise ratio larger than 10. When the radio transient signals propagate through the interstellar medium, they are affected by propagation effects such as dispersion and scattering. Scattering may limit the detectability of radio transients.
By examination of archived pulsar profiles, we investigated the impact of scattering on observed pulses. We utilized a CLEAN-based strategy to decide the scatter-broadening time, τ , under both the thin-screen and uniform-medium scattering models and to determine the scatter-broadening time frequency scaling index, α, where τ ∝ να. In most cases the scattering tail was not large compared to the pulse width at half maximum. Still, we deconvolved 1342 pulse profiles from 347 pulsars assuming a Kolmogorov spectrum of the interstellar medium turbulence. For a subset of 21 pulsars the scattering-boarding tails were suficiently long to be estimated at the lowest frequencies. Since the scatter-broadening times were only determined distinctly for the subset of pulsars at the lowest observed frequency, we were restricted to utilizing upper limits on scatter-broadening times at higher frequencies for the assessment of the scatter-broadening-time frequency dependence. We include three new direct scatter-broadening time measurements at low frequencies and they are consistent with previous studies which were scaled from higher frequencies. Our findings are consistent with a relationship between the DM and scatter-broadening time which can range over more than two orders of magnitude in DM. One of the potential reasons that we did not detect FRBs is that transients may be highly scatter-broadened at low frequencies for high DM values.Ph. D.
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Smilg, Lawrence M. (Lawrence Mitchell). "Design of a high pressure ratio fan stage to take advantage of boundary layer suction." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11681.
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Fitt, Andrew John. "Star-forming galaxies : a study of the far-infrared - radio correlation." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358651.
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Losh, Jonathan L. "Digital signal processing hardware for a fast fourier transform radio telescope." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/77447.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references.
21-cm tomography is a devoloping technique for measuring the Epoch of Reionization in the universe's history. The nature of the signal measured in 21-cm tomography is such that a new kind of radio telescope is needed: one that scales well into very large numbers of antennas. The Omniscope, a Fast Fourier Transform telescope, is exactly such a telescope. I detail the implementation of the digital signal processing backend of a 32-channel interferometer designed to help characterize the non-digital parts of the system, starting at the point analog signal enters the FPGA and ending when it is written to a file on a computer. I also describe the accompanying subsystems, my implementation of a scaled-up, 64 channel design, and lay out a framework for expanding to 256 channels.
by Jonathan L. Losh.
M.Eng.
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Randriamampandry, Solohery Mampionona. "Far-infrared-radio relations in clusters and groups at intermediate redshift." Thesis, University of the Western Cape, 2014. http://hdl.handle.net/11394/4221.
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Philosophiae Doctor - PhDIn this thesis, we present a multi-wavelength analysis of star-forming galaxies to shed new light on the evolution of the far-IR-radio relations in intermediate redshift (0.3 < z < 0.6) galaxy clusters and galaxy groups. The far-infrared (far-IR) emission from galaxies is dominated by thermal dust emission. The radio emission at 1.4 GHz is predominantly produced by non-thermal synchrotron radiation. The underlying mechanisms, which drive the far-IR-radio correlation, are believed to arise from massive star formation. A number of studies have investigated the relationship as a function of redshift in the field and have found no evolution out to at least z _ 2, however few works have been done in galaxy clusters. In nearby clusters, the median logarithmic ratio of the far-IR to radio luminosity is qFIR = 2.07_0.74, which is lower than the value found in the field, and there is an indication of an enhancement of radio emission relative to the far-IR emission. Understanding the properties of the far-IR-radio correlation in a sample of distant and massive cluster and groups plays an important role in understanding the physical processes in these systems. We have derived total infrared luminosities for a sample of cluster, group, and field galaxies through an empirical relation based on Spitzer MIPS 24 _m photometry. The radio flux densities were measured from deep Very Large Array 1.4 GHz radio continuum observations. We have studied the properties of the far-IR-radio correlation of galaxies at intermediate redshift clusters by comparing the relationship of these galaxies to that of low redshift clusters. We have also examined the properties of the galaxies showing radio excess to determine the extent that galaxy type or environment may explain the radio excess in galaxy clusters. We find that the ratio of far-IR to radio luminosity for galaxies in an intermediate redshift cluster to be qFIR = 1.72_0.63. This value is comparable to that measured in low redshift clusters. A higher fraction of galaxies in clusters show an excess in their radio fluxes when compared to low redshift clusters, and corroborates previous evidence of a cluster enhancement of radio excess sources at this earlier epoch as well. We have also investigated the properties of the far-IR-radio correlation for a sample of galaxy groups in the COSMOS field. We find a lower percentage of radio-excess sources in groups as compared to clusters. This provides preliminary evidence that the number of radioexcess sources may depend on galaxy environment. We also find that a larger fraction of radio-excess sources in clusters are red sequence galaxies.
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Whitman, Joshua (Joshua J. ). "Design of passive decay heat removal system for the lead cooled flexible conversion ratio fast reactor." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41690.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.Includes bibliographical references.
The lead-cooled flexible conversion ratio fast reactor shows many benefits over other fast-reactor designs; however, the higher power rating and denser primary coolant present difficulties for the design of a passive decay heat removal system. In order to achieve passive cooling, enhancements are needed over current designs, such as the S-PRISM and ABR, which utilize passive cooling through the reactor vessel to atmospheric air. Enhancements such as axial fins, a perforated plate, and round indentations, or dimples, were considered as additions to the hot air riser to increase heat transfer. Other enhancements include a liquid metal bond between the reactor and guard vessels, and a dual-level design which introduces ambient temperature air halfway up the vessel wall. A code was written in Java to simulate these conditions, leading to a promising case using dimples on the guard vessel wall as the primary mode of heat transfer enhancement, and including the dual-level design. A conservative estimate of dimple performance indicates that during a passive decay heat removal shutdown, bulk primary coolant temperature will peak at 713 'C, giving a 12 OC margin to clad failure. Attempts were made to refine the uncertainty within the calculations using a computational fluid dynamics code, Fluent, but these ultimately were unsuccessful. Additional studies were conducted on the static stress imparted on the vessel, and the dynamic stress caused by a seismic event. The static stress was found to be within ASME code limits. Seismic analysis determined that a seismic isolation scheme would be necessary in order to prevent damage to the vessel during an earthquake.
by Joshua Whitman.
S.B.
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Milizi, Lorenzo. "Fast radio burst e ricerca di controparti in banda ottica ed infrarossa." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17885/.
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I Fast Radio Burst (FRB) sono impulsi radio singoli molto intensi con una durata di alcuni millisecondi e di natura sconosciuta. L'elevata misura di dispersione (DM) ne suggerisce un'origine extragalattica.
Gli FRB sono localizzati con una precisione di alcuni minuti d'arco. Trovarne l'eventuale controparte multibanda e la galassia ospite e derivarne il redshift è quindi difficile.
La scoperta del primo FRB ripetitore ha permesso di localizzarne, grazie all'interferometria con il VLA, la galassia ospite con una precisione di 100 mas, identificandola come galassia nana a z=0.192 con proprietà simili ai “Green Peas", una classe di galassie note per la forte emissione dovuta alla riga [OIII].
Lo scopo di questa tesi è la ricerca delle controparti multibanda e delle galassie ospiti di FRB180301 e FRB180311. La loro rivelazione è essenziale per capire quali processi fisici diano origine agli FRB.
Le immagini sono state acquisite dai telescopi VST e VISTA di FRB180301 e FRB180311. Dato l'elevato numero di sorgenti nel campo di vista, l'analisi si concentra sulla ricerca di possibili galassie ospiti, attraverso i diagrammi colore-colore, e oggetti che mostrano una variazione della luminosità tra diverse epoche.
Le variazioni di luminosità dei candidati viene poi confrontata con le curve di luce di alcuni transienti (GRB, SN e Kilonovae) con il fine di trovare od escludere alcuni possibili tipi di progenitori.
Ulteriori osservazioni saranno necessarie per determinarne la natura e il redshift dei candidati selezionati. Per il futuro, un miglioramento nell'accuratezza della localizzazione radio è uno requisito fondamentale per la ricerca delle controparti degli FRB.
Osservazioni radio interferometriche previste e/o già in corso con Molonglo, ASKAP e CHIME, in grado di ottenere in tempo reale delle posizioni con una precisione del secondo d'arco, saranno quindi cruciali in questa ricerca.
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White, Richard F. "Exploring star formation in galaxy populations using the far-infrared-radio correlation." Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/53463/.
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In this thesis I take a close look at the far-infrared radio - correlation, a puzzlingly persistent and tight relationship identified between the far-infrared and radio luminosities of star forming galaxies. Two disparate processes are attributed to this phenomenon. In the first, starlight from massive stars is reprocessed by dust to be re-emitted in the infrared and secondly, radio emission in the form of synchrotron radiation originating in shocks driven by these same high mass stars as they end their lives as supernovae. Cosmic ray electrons are accelerated by these shocks, their paths subsequently spiralling in their host galaxies magnetic fields, produce a continuum of synchrotron radiation. I investigate this far-infrared radio correlation for a large sample of IRAS galaxies and compare my results to previous studies. I look at the effect of peak galaxy dust temperature on the correlation, dividing my sample into ‘warm' and ‘cool' bins and find a lower flux ratio in the warm sample. The correlation at low radio frequencies is tested, probing the constancy of the dominant synchrotron radiation where absorption or other effects are expected to lead to a divergence from the linear continuum spectrum. Finally I look at a smaller sample of galaxies in the ELAIS-N1 field using HerMES and GMRT data to investigate the correlation to higher redshifts. The interest and rational for investigating this correlation is its evident link to star formation. Any deviation for example will imply an evolution in one or both of these processes which are closely linked to star formation. With the advent of new dedicated low frequency array radio telescopes such as LOFAR it is increasingly necessary to trust the correlation at these longer wavelengths if observational data is to be used as a reliable predictive tool in the study of star formation.
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Virdee, Jasmeer. "The impact of radio-AGN on star formation across cosmic time." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:12345424-441e-4efb-bd26-efadabb83fbe.
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This thesis presents a detailed study of the impact of radio-AGN on star formation and the interstellar medium (ISM) of galaxies across cosmic time. To do this, this thesis uses far-IR/sub-mm data from the Herschel Space Observatory. I create a well-selected sample of 1599 radio sources using the NRAO VLA Sky Survey (NVSS) and Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) data in combination with the UKIRT Infrared Deep Sky Survey - Large Area Survey (UKIDSS - LAS) data. I find that the far-IR luminosities and dust temperatures of radio galaxies are lower in comparison to those of non-radio-detected galaxies. This luminosity deficit grows with increasing stellar mass. I argue that the reasons for these differences is probably due to indirect radio-AGN feedback, i.e. radio jets mechanically heat the halo-environment, preventing external sources of cold gas from entering the host and forming stars. The far-IR luminosity and dust temperature is found to decrease as a function of radio source size. I find the most likely explanation for this is jet-induced star formation while the jets are confined to the ISM. Finally, a method for identifying reliable high-z, star-bursting radio sources in the H-ATLAS is described with which statistically significant studies of radio-jet induced star formation may be undertaken.
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Ma, Li. "Ecophysiology of the effect of red to far-red light ratio on selected weed and crop species." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63174.
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Plants growing in canopies are exposed to reduced light intensity as well as low red/far-red light ratios, a signal of impending competition. In order to advance our understanding of the eco-physiological role of red/far-red ratio in agroecosystems, growth chamber and greenhouse studies were conducted to investigate 1. the growth and morphological responses of common lamb’s-quarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.) and tomato (Solanum lycopersicum L.) to different red/far-red ratios, 2. how leaf optical properties at red (660 nm) and far-red (730 nm) wavelengths change with leaf position and plant development, and 3. if red/far-red ratio influences response of corn (Zea mays L.), lettuce (Lactuca sativa L.), and pigweed plants to UV-B radiation. Three red/far-red ratios were achieved by using supplemental far-red lamps in growth chambers, while maintaining the photosynthetically active radiation. Results showed that red/far-red ratio treatment influenced several growth and allometric parameters and tomato, lamb’s-quarters, and pigweed differed in this regard. This differential response among species suggests that fluctuations in the red/far-red ratio in canopies could impact inter-plant interactions among these species. Red/far-red ratio in a plant canopy is affected by leaf optical properties. A study of leaf optical properties of lamb’s-quarters, pigweed and tomato using a CI-710 Miniature Leaf Spectrometer showed that leaf optical properties changed with leaf position and plant development, which could modify the light environment in canopies comprising populations of these species. Interestingly, these species differed in this regard, suggesting differences in their ability to signal potential competition. Leaf optical properties, as well as leaf position and plant development effects, therefore, should be taken into consideration in assessing the eco-physiological functions of a vegetation cover. Effect of pre-exposure to low red/far-red ratio on plant susceptibility to UV-B radiation could impact plant interaction. However, my research showed that red/far-red ratio pre-treatment and the associated change in anthocyanin concentration did not alter the response of corn, lettuce and pigweed seedlings to enhanced UV-B radiation. This improves our understanding of the eco-physiological role of these environmental stressors in agro-ecosystems, where both red/far-red ratio and UV-B levels fluctuate.Land and Food Systems, Faculty of
Graduate
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Rost, Jon Christian 1969. "Fast ion tails during radio frequency heating on the Alcator C-Mod tokamak." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47459.
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O'Rourke, Douglas James Peter. "Spectral modeling of dusty galaxies, and evolution of the far infrared-radio correlation." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610847.
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Liu, Haotian, and 劉昊天. "Analytical and numerical procedures for fast periodic steady-state and transient analyses of nonlinear circuits." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206326.
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Girard, Alexandre 1987. "Fast and strong lightweight robots based on variable gear ratio actuators and control algorithms leveraging the natural dynamics." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111689.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 191-196).
In many applications, robots have to bear large loads while moving slowly and also have to move quickly through the air with almost no load. These type of bi-modal tasks, with conflicting requirements in terms of operating speeds and desired impedances, often lead to the use of oversized and inefficient actuators which are inhibitory particularly for mobile robots. Multiple gear ratios, like in a powertrain, address this issue by allowing an effective use of power over a wide range of output speeds, by enabling significant changes to the reflected intrinsic actuator impedances and by making possible the leveraging or attenuation of the natural load dynamics. This thesis aims to develop the technological solutions needed to use variable gear ratio actuators and exploit the advantages of variable transmissions in a robotic context. First, by addressing the issue of how to make fast and seamless gearshifts between two very different reduction ratios under diverse load conditions, with a solution based on a dual-motor actuator architecture and a control scheme using the null space. Second, by developing control algorithms that select optimal gear ratios dynamically based on state feedback, to move with minimal motor torques and to adjust the output impedance appropriately given a task. The proposed approach exploit variable transmissions not merely for increasing maximum torque and speed, but also to significantly alter the dynamic properties, including load sensitivity, robustness, and backdrivability. Simulations and experiments using a novel lightweight robotic arm using three custom-built dual-speed dual-motor actuators are presented. Results demonstrate very fast gear shifting in highly dynamic situations with dual-speed dual-motor actuators, and show that actively changing gear ratios using the proposed control algorithms can lead to an order-of-magnitude reduction of necessary motor torque and power.
by Alexandre Girard.
Ph. D.
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Upadhyaya, Parag. "A 5 GHZ low power, low jitter and fast settling phase locked loop architecture for wireline and wireless transceiver." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Dissertations/Summer2008/P_Upadhyaya_072308.pdf.
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Manicka, Naveen. "GNU Radio testbed." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 104 p, 2007. http://proquest.umi.com/pqdweb?did=1338919411&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Rawat, Vineet. "High-order solution of radio propagation problems using the multi-level fast multipole algorithm." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81562.
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Wireless network planning requires accurate, site-specific urban and indoor radio propagation models. Traditionally, such models have been developed using approximate asymptotic methods. This thesis examines rigorous solution methods for radio propagation in electrically large environments.The high-order locally corrected Nystrom (LCN) method is applied to the combined field integral equation (CFIE) for scattering from perfect electrical conductors (PEC) in two dimensions. The direct solution of the resulting linear system of equations requires O(N2) time per iteration of an iterative solver. Application of the multi-level fast multipole algorithm (MLFMA) reduces iteration time to O(Nlog N). The MLFMA employs an approximation however, and the error introduced must be controlled via the selection of appropriate parameters.
An implementation of the LCN method and MLFMA is tested using various electrically large scattering bodies. The solution of a simple urban radio propagation problem is then examined and the feasibility of its rigorous solution is demonstrated.
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Dicken, Daniel. "The origin of the mid- to far-infrared emission from powerful radio-loud AGN." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505436.
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Until recently, the advantages of using mid- to far-infrared (MFIR) observations to investigate the thermal dust emission from active galaxies (AGN) had not been fully exploited. Therefore, this thesis presents the results from deep MFIR imaging observations (Spitzer/MIPS) of complete samples of 2Jy and 3CRR radio galaxies (0.03< z <0.7), as well as the results of two complementary radio imaging program (ATCA, VLA) for the 2Jy sample at high radio frequencies. The Spitzer data have been used to investigate the origin of the thermal MFIR emission, focussing on the correlations between 24, 70ILm and [O111j..\5007 luminosities. Because [0111j..\5007 emission line luminosity acts as a proxy for intrinsic AGN power, the tight correlations found between MFIR and [0111j..\5007 luminosities provide strong evidence that direct AGN illumination is the primary heating mechanism for the dust producing both the mid-IR and far-IR continuum. Using optical spectroscopic information about the level of recent star formation activity in the host galaxies, I deduce that starbursts significantly boost the far-IR emission in only a minority ofradio-Ioud AGN (17-35%). This result is supported by analysis of polycyclic aromatic hydrocarbon star formation tracers in objects observed with Spitzer/IRS as well as the analysis of MFIR colours. Given the lack of optical and infrared evidence for starburst activity, it is unlikely that the majority of powerful radio-loud AGN are triggered at the peaks of major, gas rich mergers. In addition, at high [0111] luminosities, the similarities between the MFIR properties (luminosities and colours) of broad-line radio galaxies (BLRG), quasars and narrow line radio galaxies support orientation-based unified schemes for powerful radio sources. However there remain groups of objects at low redshifts/luminosities, (e.g. weak line radio galaxies and low redshift 3C BLRG) whose characteristics at MFIR wavelengths are not readily explained in the simplest versions of such schemes. Overall, the results presented here underline the merits of observing complete samples of AGN atMFIR wavelengths. Much of the work presented in this thesis forms the basis of 3 publications (Tadhunter et al., 2007, Dicken et al., 2008, 2009). This work is based [in part] on observations made with the following facilities. Spitzer Space Telescope: operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. ATCA: operated by the Australia Telescope National Facility, a division of CSIRO. the VLA: operated by The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. as well as on observations made with ESO Telescopes at the Paranal Observatory. This research has also made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. I also acknowledge finacial support from the STFC.
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Bookwalter, Candice Anne. "CONTINUOUS SAMPLING IN MAGNETIC RESONANCE IMAGING." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1194049081.
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