Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early universe and their connection to massive galaxy formation. However, extremely luminous quasars at high redshift are very rare objects. Only wide-area surveys have a chance to constrain their population. The Sloan Digital Sky Survey (SDSS) has so far provided the most widely adopted measurements of the quasar luminosity function at z > 3. However, a careful re-examination of the SDSS quasar sample revealed that the SDSS quasar selection is in fact missing a significant fraction of z greater than or similar to 3 quasars at the brightest end. We identified the purely optical-color selection of SDSS, where quasars at these redshifts are strongly contaminated by late-type dwarfs, and the spectroscopic incompleteness of the SDSS footprint as the main reasons. Therefore, we designed the Extremely Luminous Quasar Survey (ELQS), based on a novel near-infrared JKW2 color cut using Wide-field Infrared Survey Explorer mission (WISE) AllWISE and 2MASS all-sky photometry, to yield high completeness for very bright (m(i) < 18.0) quasars in the redshift range of 3.0 <= z <= 5.0. It effectively uses random forest machinelearning algorithms on SDSS and WISE photometry for quasar-star classification and photometric redshift estimation. The ELQS will spectroscopically follow-up similar to 230 new quasar candidates in an area of similar to 12,000 deg(2) in the SDSS footprint to obtain a well-defined and complete quasar sample for an accurate measurement of the brightend quasar luminosity function (QLF) at 3.0 <= z <= 5.0. In this paper, we present the quasar selection algorithm and the quasar candidate catalog.

This thesis is aimed at the study of high angular momentum states in neutron deficient nuclei in the mass 60 region, with approximately equal numbers of protons and neutrons, (N~Z). The main motivations of this work are to provide an insight into the mechanisms for generation of high angular momentum states in a limited particle valence space above the N=Z=28 doubly magic core, and to investigate the role of the isospin quantum number in heavy N=Z nuclei. The decay scheme for the odd-odd N=Z nucleus 6231Ga has been deduced for the first time, and the decay schemes for 61Zn and 61Cu have been extended. The data came from two experiments, the first using the reaction 24Mg + 40Ca at a beam energy of 65 MeV, performed at the Argonne National Laboratory, Chicago, US, using the germanium gamma-ray detector array 'AYEBALL' in conjunction with the Argonne Fragment Mass Analyzer and a gas filled ionisation chamber. The second experiment using the reaction 28Si + 40Ca at a beam energy of 88 MeV was performed at the Niels Bohr Institute, Riso, Copenhagen, Denmark using the 'PEX' gamma-ray detector array with a charged particle detector ball and an array of liquid scintillator neutron detectors. The data analysis techniques and results of the experimental analysis are presented. Gamma-ray energy spectra for different nuclei are shown according to the mass, neutron number and proton number of the nucleus. The proposed decay schemes are justified by coincidence and DCO arguments, and are compared to shell model calculations using a restricted pf5/2 g9/2basis. In the case of 62Ga, these are then compared with the latest IBM-4 calculation, which explicitly includes T=0 and T=1 bosons. Suggestions are also made for future work to complement this data.

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Many neurones in the thalamus, like neurones in other parts of the CNS are excited by iontophoretlcally applied acetylcholine (ACh), and it has been suggested that ACh may be involved in synaptic transmission in the thalamus. In these experiments, the iontophoretlc technique was employed to investigate the location, and the neurophysiological and pharmacological properties of neurones in the ventrolateral nucleus of the thalamus (VL), which responded to electrical stimulation of the ipsilateral nucleus of the posterior commisure (NPC). Stimulation of the contralateral brachium conjunetivum (BC) was used to confirm the presence of the recording micropipette in VL. Four drugs were applied in various sequences to most neurones encountered above, in and below VL. DL-homocysteate (DLH) was used for the activation and localisation of quiescent neurones; ACh was applied to test whether the neurones were cholinoceptivej eserine (physostigmine) was used as an anticholinesterase; and atropine was used as a muscarinic blocking agent. Choiinoceptive cells were found above (3.0-6.0 mm below the fornix), and In VL (0.0-10.0mm below the fornix), the highest proportion being located in VL. The majority of cholinoceptive cells in VL responded to NPC and to BC stimulation. Cholinoceptive neurones located above VL were not evoked either by NPC or BC stimulation, while those in the lowest part of VL were evoked by NPC stimulation only. Although atropine blocked the effect of iontophoretically applied ACh, It did not affect synaptic responses evoked by stimulation of NPC and/or BC fibers. Eserine excited some cells and potentiated the actions of ACh. These results indicate that a pathway arising from the NPC projects to the ipsilateral VL and that this fiber tract is non-cholinergic. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

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Magister Scientiae - MSc / The aim of nuclear structure physics is to study the interplay between singleparticle and collective degrees of freedom in nuclei and to explain how nuclei get excited and decay under di erent external conditions, such as strong electric and magnetic elds. If nuclei absorb a large amount of energy and angular momentum, like in a scattering reaction when you bombard a target that is in the ground state with a projectile at high bombarding energies, the energy from the projectile gets transfered to the target and vice versa, hence both projectile and target may get excited. During the de-excitation process nuclei may release the energy in a form of electromagnetic radiation (gamma rays) which carries angular momentum. The atomic nucleus is a many-body system, whose structure is de ned in terms of interactions between protons and neutrons. In nature there are only around 300 stable isotopes [1]. They are all in their ground states (although some are in a low-energy excited isomeric state with a long lifetime). To study excited states in these nuclei one needs to provide energy to the system. In addition, there are some 3000 unstable nuclei, most of which do not exist in nature. Many have been produced and studied in research laboratories, and there could be more than 3000 other unstable nuclei that can in principle exist in astrophysical environments, but have not yet been synthesized on Earth [1].

published_or_final_version / Zoology / Master / Master of Science