A measurement of the primordial B-mode polarisation of the Cosmic Microwave Background would provide direct evidence of inflation in the early universe. The extremely weak nature of the B-mode signal necessitates an instrument with a high sensitivity and precise control over systematic effects. Multi-mode antenna feed horns offer higher sensitivity than their single-mode counterparts, however their behaviour is much more complex. The Short Wavelength Instrument for the Polarisation Explorer (SWIPE) onboard the Large Scale Polarisation Explorer (LSPE) is one instrument planning to implement multi-mode feed horns. SWIPE will attempt to detect the primordial B-mode at large angular scales, measuring the sky in three bands at 140, 220 and 240 GHz. A single on-axis High-Density PolyEthylene (HDPE) lens and polarisation-splitting wire grid combine to focus the radiation from the sky onto two focal planes of multi-mode horns feeding bolometric detectors. A large diameter rotating metal-mesh half-wave plate allows both polarisations to be measured by the same pixel, therefore bypassing many detector systematics. Simulations are performed to predict the sky beam for two key pixels: closest to and furthest from the centre of the focal plane. For the 140 GHz channel the cross-polarisation is predicted, and the optimum location at which to place the telescope’s focus behind the horn aperture to maximise gain and optimise beam shape is investigated. A measurement of the multi-mode horn is performed using a room-temperature bolometer. An investigation is also conducted to assess to what extent the same measurements can be performed using a coherent measurement system such as a vector network analyser. A working coherent measurement technique is devised, however it is limited to horns carrying only the first 3 modes.

A longitudinal pilot study to compare, in children with reduced overbite malocclusions associated with oral habits (finger-sucking and tongue-thrusting), the effects of the experimental Myofunctional Trainer (MFT; Myofunctional Research Co.) and the conventional Bluegrass appliance (BG) on dento-alveolar relations, tongue position, and on speech. Methods: The experimental group received the MFT appliance while the control group received the BG appliance. Dento-alveolar changes were assessed by cephalometry and study models. Longitudinal midsagittal 2-dimensional B-mode ultrasound scans of the tongue surface were performed to determine tongue position. Speech acceptability tests were also performed. Results & Conclusions: The BG appliance was successful in breaking the finger-sucking habit. The MFT appliance showed only partial success which could be attributed to lack of compliance. At the end of treatment, the open bite was reduced in both groups due to dento-alveolar changes. The BG appliance had a deleterious effect on speech acceptability while in place, while there was no such effect with the MFT appliance.

A longitudinal pilot study to compare, in children with reduced overbite malocclusions associated with oral habits (finger-sucking and tongue-thrusting), the effects of the experimental Myofunctional Trainer (MFT; Myofunctional Research Co.) and the conventional Bluegrass appliance (BG) on dento-alveolar relations, tongue position, and on speech. Methods: The experimental group received the MFT appliance while the control group received the BG appliance. Dento-alveolar changes were assessed by cephalometry and study models. Longitudinal midsagittal 2-dimensional B-mode ultrasound scans of the tongue surface were performed to determine tongue position. Speech acceptability tests were also performed. Results & Conclusions: The BG appliance was successful in breaking the finger-sucking habit. The MFT appliance showed only partial success which could be attributed to lack of compliance. At the end of treatment, the open bite was reduced in both groups due to dento-alveolar changes. The BG appliance had a deleterious effect on speech acceptability while in place, while there was no such effect with the MFT appliance.

Inflation, which posits an exponential expansion in the early universe, is well motivated since it resolves questions that are left unexplained by standard LCDM cosmology, such as the flatness and homogeneity of the universe. The exponential expansion of universe during inflation explains the structure in the universe by freezing out the quantum fluctuations of space. These quantum fluctuations are also expected to generate a background of gravitational waves which would then imprint a B-mode polarization signal on the Cosmic Microwave Background. The Bicep2 and Keck Array experiments search for B-mode polarization from inflationary gravitational waves in the Cosmic Microwave Background. Bicep2 and the Keck Array use small aperture, cold, on-axis refracting optics optimized to target the degree angular scales at which the inflationary B-mode polarization is expected to peak. In this thesis we describe the optical design of Bicep2 and the Keck Array. The small aperture design allows us to fully characterize the far-field performance of the instrument on site at the South Pole using thermal and amplified sources on the ground. We describe the efforts taken to characterize the main beam shapes of each polarization sensitive bolometer, as well as the differential beam paramters of each co-located orthogonally polarized detector pair. We study the residual temperature to polarization leakage induced by the beam mismatches after the principle modes have been mitigated in the analysis. / Physics

Ultraljudsdiagnostik baseras på propagering av mekaniska vågor och används för att avbilda tvärsnitt av kroppen i realtid. Prestandan, med avseende på kontrast, upplösning och måttmätningar, av CONTEC CMS600B-3, en relativ billig maskin är av intresse. Hur volymen av en fantom, dess ytarea och frekvens på utskickade vågor påverkar uppvärmningen av vävnader är även av intresse. Det undersöktes med ultraljudsmaskinerna CONTEC CMS600B-3 och Philips Lumify för att få resultat som inte beror på endast en maskin.  Axiella upplösningen på CONTEC CMS600B-3 uppmättes med hjälp av ett gem till 0,61 mm och den laterala upplösningen till 1,27 mm med hjälp av ett snitt i cement. Maskinens måttmätningar hade en relativ avvikelse   beroende på mätning. Resultat för reflektionskoefficienten visade att ultraljudsmaskinen har en funktion som kompenserar för attenuering och förstärker signaler med låga amplituder.  Temperaturmätningarna undersöktes genom att skapa fantomer som efterliknar mänskliga vävnader med olika volymer och ytareor. En undersökning med ultraljudsmaskinerna visade att mer temperaturökning sker då ytarean ökas när volymen hålls konstant. Med avseende på säkerhet i temperaturökning, axiell upplösning och area/omkrets mått uppfyller CONTEC CMS600B-3 inte standarden och kan därmed inte användas inom sjukvården. / Diagnostics with ultrasound are based on propagation of mechanical waves and is used for imaging cross-section of the body in real-time. Performance, regarding contrast, resolution, and size measure, of CONTEC CMS600B-3, a relatively cheap machine is of interest. How volume of a phantom, its surface area, and frequency of the waves affects the heating of the tissues is also of interest. It was measured using ultrasound machines CONTEC CMS600B-3 and Philips Lumify to obtain results independent of the machine used.   The axial resolution of CONTEC CMS600B-3 was established with a paperclip to be 0.61 mm and the lateral resolution was measured to be 1.27 mm using concrete with a triangular slit. Measurements of the machine had a relative deviation was   depending on the measure. Results of the reflection coefficient indicated that CONTEC CMS600B-3 has a built-in function that compensates for loss of intensity due to attenuation and amplifies signals with lower amplitude to produce a B-mode image that the user can understand.  Temperature measurements were done on phantoms that mimic the human body with different volumes and surface areas. An investigation with ultrasound machines showed an increase in temperature with increased surface area as the volume is held constant. When looking at safety with temperature rise, axial resolution and area/circumference measurements, CONTEC CMS600B-3 does not meet the standard and therefore cannot be used in healthcare.

Ultrasound imaging systems are a safe and affordable imaging modality with the disadvantage of low spatial resolution, especially for assessing smaller vessels. However, with the implementation of super-resolution ultrasound imaging techniques, studies have shown promising results in achieving a resolution below the diffraction limit. Super-resolution ultrasound imaging techniques takes advantage of the point spread function to localize the centroid of the ultrasound contrast agents in an image. By superimposing thousands of these images, a super-resolved image of the localized and tracked contrast agents can be created, which presents an image where vessels down to a few micrometers can be resolved. The purpose of this master’s thesis was to implement super-resolution ultrasound imaging, test different localization methods and analyze them by using different ultrasound contrast agent concentrations. Grayscale ultrasound images were acquired using the Verasonics system for three different microbubble concentrations. The super-resolution ultrasound imaging program was executed on the grayscale images using three different localization methods, Gaussian fit, No-shift and Interpolation based scheme. The microbubbles were localized and tracked over several frames to create a super-resolved image which had the pixel resolution of a 10th of the wavelength. Significant improvements were demonstrated in the super-resolved images compared to the grayscale images. The higher microbubble concentrations resulted in a higher number of localized and tracked microbubbles. While the low concentration exhibited lower values. Comparing the methods, Gaussian fit and No-shift detected higher number of microbubbles than the method Interpolation. Although further analysis is needed, the thesis concluded that using Gaussian fit as a localization method and higher microbubble concentrations, a super-resolved image can be produced even if the program is tested on fewer images. / Ultraljudsavbildning är en säker och billig avbildningsmodalitet med en låg spatial upplösning, framför allt vid avbildning av mindre kärl. Men med implementering av ultraljudsavbildningstekniker med superupplösning har studier visat lovande resultat för att uppnå en upplösning under diffraktionsgränsen. Ultraljudsavbildningstekniker med superupplösning utnyttjar punktspridningsfunktionen för att lokalisera ett ultraljudskontrastmedels centerpunkt i en bild. Genom att överlagra tusentals av dessa bilder skapas en superupplöst bild av det lokaliserade och spårade kontrastmedlet. Med hjälp av superupplösta bilden kan kärl som är några mikrometer urskiljas. Syftet med denna masteruppsats var att implementera ultraljudsavbildning med superupplösning, testa olika lokaliseringsmetoder och analysera de genom att använda olika koncentrationer av mikrobubblor. Gråskale ultraljudsbilder samlades in med hjälp av Verasonics systemet för tre olika koncentrationer av mikrobubblor. Superupplösningsprogrammet var exekverad på gråskalebilderna för tre olika lokaliseringsmetoder, Gaussian fit, No-shift och Interpolation based scheme. Mikrobubblorna lokaliserades och spårades över flera bilder för att skapa en superupplöst bild vilket hade en tiondel av våglängden som pixelupplösning. Resultatet presenterade en märkbar förbättring i de superupplösta bilderna jämfört med gråskalebilderna. De högre koncentrationerna med flera mikrobubblor resulterade i ett högre antal lokaliserade och spårade mikrobubblor, medan den lägre koncentrationen gav färre lokaliserade mikrobubblor. Metoderna Gaussian fit och No-shift detekterade flera mikrobubblor än metoden Interpolation. Slutsatsen visade att användningen av lokaliseingsmetoden Gaussian fit med högre koncentrationer av mikrobubblor ger en superupplöst bild även om programmet exekveras på färre bilder.

The C-Band All-Sky Survey (C-BASS) is a 1 GHz bandwidth survey of the radio sky in both intensity and polarization at a frequency of 5 GHz and with a resolution of 0.8. Northern and Southern sky coverage is provided by antennas located at the Owen’s Valley Radio Observatory (OVRO) in California, and the MeerKAT support base in South Africa, respectively. The primary science goal of C-BASS is to provide a highly sensitive C-Band all sky intensity and polarization map to augment the WMAP/Planck surveys. Removal of foregound contamination will place a limit on the success of Cosmic Microwave Background (CMB) experiments that attempt to detect the B-Mode polarization of the CMB. We will provide a HEALPix map (N_side=128) with an r.m.s. noise of 0.13 mK/pixel in Stokes Q and Stokes U, and a confusion limited r.m.s. noise of 0.8 mK/pixel in Stokes I. Removal of foregrounds at the higher frequency CMB surveys will be significantly improved by this lower frequency constraint. This thesis describes the development of the C-BASS gain-stabilized receiver capable of making sensitive measurements of both galactic total intensity and polarization. The receiver features a novel digital backend to provide spectral detail across the frequency band of interest. The analog signal conditioning uses a double sideband mixer to mix the RF frequencies to a DC–1000 MHz baseband for digitization. By changing the mixer frequency and/ or duplicating the signal conditioning and digital hardware, the RF frequency coverage can be modified for other projects. I also describe the process of converting a 7.6 m telecommunications dish to a high performance radio astronomy platform. The discussion includes dish surface measurements, optical design, and the development of an inexpensive telescope servo controller. The antenna conversion process and receiver design can be used to significantly reduce capital costs of future experiments, which is especially useful for short timescale experiments. The African VLBI (Nordling, 2012) is currently following a similar route to repurpose antennas across the African continent.

The cosmic microwave background (CMB) provides unprecedented details about the history of our universe and helps to establish the standard model in modern cosmology. With the ongoing and future CMB observations, higher precision can be achieved and novel windows will be opened for studying different phenomena. Non-Gaussianity is one of the most exciting effects which fascinate many cosmologists. While numerous alternative inflationary models predict detectable primordial non-Gaussianities generated during inflation, the single-field slow-roll inflation of the standard model is known to produce negligible non-Gaussianities. However, post-inflationary processes guarantee the generation of non-Gaussianities through the nonlinear evolution of our universe after inflation, regardless of the underlying inflationary theory. These non-Gaussianities not only may contaminate the potential primordial non-Gaussian signals, but also may offer independent tests for late-time physics (such as General Relativity). Therefore, it is of great interest to study them quantitatively. In this thesis, we will study the post-inflationary non-Gaussianities in two main aspects. First, we calculate the CMB bispectrum imprinted by the 2nd-order perturbations during recombination. We carry out a numerical calculation including all the dominant effects at recombination and separate them consistently from the late-time effects. We find that the recombination bispectrum is subdominant compared to the ISW-lensing bispectrum. Although the effect will not be detectable for the Planck mission, its signal-to-noise is large enough that they present themselves as systematics. Thus, it has to be taken into account in future experiments. Second, we formulate the lensing, redshift and time-delay effects through the Boltzmann equation. The new formalism allows us to explicitly list out all the approximations implied in the canonical remapping approach. In particular, we quantify the correction of the CMB temperature power spectrum from the lens-lens couplings and confirm that the correction is small.

An adequate vascular perfusion status is essential not only to maintain life, but to ensure the proper physiology of the different systems that form the animal’s body. Due to its role in the transport of oxygen and nutrients toward, and the removal of cellular waste products away from the body’s tissues, the circulatory system is responsible for the maintenance of body homeostasis. Production related functions in farm animals are not an exception, and directly depend on sufficient vascular physiology. In the past, the study of blood flow in large domestic species was restricted to highly invasive techniques. However, even when such techniques are the foundation for the actual understanding of vascular dynamics in these animals, their limited feasibility and potential impact over the normal vascular physiology represent significant limitations to these approaches. Recently, the development and application of non-invasive technologies (i.e., Doppler and B- mode ultrasound) to the area of animal sciences has provided the potential for the study of vascular dynamics while, the negative implications aforementioned are avoided. In our studies, these technologies were applied to assess the role of the circulatory system on different production related variables such as: temperament, reproduction, and milk production in the bovine. A tendency toward differences in jugular blood flow was associated with the temperament in beef calves in this study. Also, a significant increase in vasodilation in the uterine arteries of beef cows was found to be associated with a numerically higher reproductive efficiency (i.e., pregnancy rates). Moreover, an increase in blood flow towards the mammary gland in dairy cows was associated with administration of bovine somatotropin. In conclusion, B- mode and Doppler ultrasound resulted in tools able to reflect the essential role of an adequate vascular perfusion in the normal physiology and productive performance in the bovine. However, in real farm scenarios the feasibility of these techniques in large domestic species is limited. Therefore, further specialization of this instrument to the conditions existent in such farm scenarios are recommended to improve its feasibility and to significantly accelerate the rate of knowledge acquisition in this area.

Ultrasound imaging is a safe and popular imaging technique that relies on received radio frequency (RF) echos to show the internal organs and tissue. B-mode (Brightness mode) is the typical mode of ultrasound images generated from RF signals. In practice, the real processing algorithms from RF signals to B-mode images in ultrasound machines are kept confidential by the manufacturers. The thesis aims to estimate the process and reproduce the same results as the Ultrasonix One ultrasound machine does using deep learning. 11 scalar parameters including global gain, time-gain-compensation (TGC1-8), dynamic range and reject affect the transformation from RF signals to B-mode images in the machine. Data generation strategy was proposed. Two network architectures adapted from U-Net and Tiramisu Net were investigated and compared. Results show that a deep learning network is able to translate RF signals to B-mode images with respect to the controlling parameters. The best performance is achieved by adapted U-Net that reduces per pixel error to 1.325%. The trained model can be used to generate images for other experiments.