The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.

Internal jugular vein ectasia (dilatation of the internal jugular vein) is a rare clinical entity, often undiagnosed. Usually it presents as an asymptomatic, soft, compressible neck swelling that increases in size on Valsalva's manoeuvre. Our report describes right internal jugular vein ectasia in a 15-year-old girl who presented to us with intractable paroxysmal cough. The entity was suspected on ultrasound imaging and confirmed by computed tomography scan and Doppler. Ligation and excision of the dilated vein almost immediately cured her cough. The probable reason for the cough was the pressure exerted by the dilated vein on the vagus nerve.

Teratomas affecting the head and neck are rare tumours of ambiguous origin. The benign form is seen in children and mostly affects the nasopharynx. Malignant tumours in the upper jaw have been reported rarely. They are almost exclusively seen in the adult male. They are highly aggressive tumours that are difficult to diagnose pre-operatively due to the varied histological patterns. Treatment options available are surgery, radiotherapy or a combination of both. Despite intensive treatment, the prognosis is still poor. A rare case of teratocarcinosarcoma of the nose, paranasal sinuses and nasopharynx in a 25-year-old male is presented. The tumour had a non-germ cell tumour origin. The clinical features, pathologic characteristics and treatment are detailed. It was managed by surgery, radiotherapy and chemotherapy.

A new type of HF solution, HF-acetonitrile (MeCN), has been employed to produce 10-30 μm thick porous silicon (P-Si) layers by photoelectrochemical etching of different types of Si wafers, Si(100), Si(111) and polycrystalline Si, with different resistivities. A combined optical, surface and nuclear microscopic assessment of these P-Si layers was performed using photoluminescence (PL), Raman scattering, X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). The PL emission intensities, Raman line shapes and structural features are strongly dependent on the properties of the substrates such as the crystallinity and resistivity of the Si wafers used for forming P-Si. With increasing resisitivity of the Si(100) wafers, the resulting P-Si layers show a slight blue-shift of their visible light emission peak energy, an up-shift of the peak position and a narrowing of the band width of the dominant Raman band, and a decrease in the amount of residual elemental Si on the surface. Those Si(l 11) wafers, etched in HF-MeCN, showed no porous structures and no visible light emission.

Epitaxial α-Fe films deposited on H-terminated Si(111) surfaces by electron beam evaporation in ultra high vacuum were studied using ion channeling/Rutherford Backscattering spectrometry (RBS). A 700 Å thick Fe film deposited on a Si(1 11) substrate at room temperature has a surface minimum yield, χmin, of 22% at 2 MeV energy of 4He+ ions along Si <111>. A rapidly increasing yield in the aligned spectrum with the depdi of the film shows the presence of defects throughout the film. The sharp lower energy edge of the Fe signal indicates the absence of an amorphous region or a suicide layer at the interface. This establishes epitaxial growth of iron film on Si(111), a result supported by x-ray diffraction and transmission electron microscopy studies. A 700 Å thick iron film deposited at 300 °C shows a surface minimum yield of 12%. Ion channeling/ backscattering spectra of 1400 Å and 3000 Å thick Fe films deposited at 300 °C on Si(111) substrates show a χmin of about 3% for both films, indicating a substantial reduction in the defect density in the thicker Fe films. Etching of Si(111) substrates in either a 10% HF solution or a NH4F solution does not change the crystalline quality of the iron films significantly.

High energy ion mixing occurs when an ion beam of a few hundred keV bombards an interface under the surface. Low energy ion mixing arises when an ion beam of a few keV bombards an interface near the surface during, for example, sputter depth profiling and low energy ion assisted deposition. At low temperatures, the rate of both high and low energy ion mixing can be influenced by thermodynamic parameters, such as the heat of mixing and the cohesive energy of solids. These effects are demonstrated by ion mixing experiments using metallic bilayers consisting of high atomic number elements. A model of diffusion in thermal spikes is used to explain this similarity. Low energy ion mixing can also be strongly affected by surface diffusion and the morphological stability of thin films. These effects are illustrated using results obtained from sputter depth profiling of Ag/Ni bilayers at elevated temperatures. High energy ion mixing at low temperatures can be influenced by the anisotropic momentum distribution in a collision cascade as seen from a set of marker experiments to determine the dominant moving species in high energy ion mixing. These similarities and differences between high and low energy ion mixing illustrate the diversity of ion-solid interactions.

Grain growth as a function of annealing temperature in Y–Ba–Cu oxide superconducting thin films is presented. Effects of excess Cu on the temperature dependence of the resistance, grain growth, and sheet resistivity are discussed. This is the first systematic study of the microstructure of thin films formed by the nonvacuum technique of metallo organic deposition. The Cu-rich films show an anomalous behavior in the resistivity at 220–240 K. The presence of excess Cu was found to enhance grain growth for films annealed below the melting point of the 1–2–3 phase. Films deposited on 〈100〉 SrTiO3 and rapid thermal annealed showed partial epitaxial growth of the 1–2–3 phase. The analytical techniques of Rutherford backscattering spectrometry, ion channeling, x-ray diffraction, scanning electron microscopy, electron microprobe analysis, sheet resistivity, and temperature versus resistance measurements have been used in this study.

Ion backscattering and channeling techniques have been employed to measure the etching rate of amorphous and single crystal Si by XeF2 under similar conditions.Both (100) Si on sapphire and (111) Si on spinel showed higher etching rates compared to amorphous Si.However, measurements of the etching rate using a Si cell aligned to the axis and along the planes under similar conditions did not show appreciable difference in the etching rate compared to the etching rate with random orientation of the cell.Presence of the analyzing 4He+ beam during etching enhances the etching rate to twice the value when compared to post etching analysis with the same beam.The enhancement of the etching rate due to ion induced decomposition of XeF2 have been considered in the explanation of the experimental results.

Let Sa (h) denote the class of analytic functions f on the unit disc E with f (0) =0 = f′ (0) −1 satisfying , where (a real), denotes the Hadamard product of Ka with f, and h is a convex univalent function on E, with Re h > 0. Let . It is proved that F ε Sa (h) whenever f ε Sa (h) and also that for a ≥ 1. Three more such classes are introduced and studied here. The method of differential subordination due to Eenigenburg et al. is used.