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Scientific interest in large-scale anisotropy measurements is now focused on intrinsic effects, which could tell us much about the early Universe. Current experimental precision of better than 10−4 K begins to probe for interesting physical processes. However, at these levels of precision systematic effects and foreground sources present serious difficulties. Some recent results from balloon flights of a maser radiometer (λ 1.2 cm) and a cooled mixer (λ 3 mm) are discussed and interpreted. The dipole effect gives a velocity for the Local Group in the general direction of the Virgo cluster. The Earth's motion is clearly seen. There is no quadrupole detected at a level of ΔT/T ∼ 5 × 10−5.
Preston et al (1976) and Burke (1982, these proceedings) have long extolled the virtues of launching a radio telescope into space to increase VLBI baseline lengths and thus angular resolution, and to provide a much enhanced image formation capability. The scientific motivation for this has been covered in a number of memoranda referenced by Burke in these proceedings, and by Anderson et al (1982). Efforts to mobilise western astronomical support for space VLBI met with success in late 1982 at a meeting of US and European radio astronomers in Toulouse, France, at which a decision was taken to propose a joint mission to ESA and NASA. Shortly thereafter, a formal proposal was made to ESA (Anderson et al 1982) for a free flying satellite in an elliptical orbit out to 15000 km from the Earth, designed to observe in concert with the major ground-based VLBI networks and arrays. The mission, dubbed QUASAT, was received favourably in both ESA and NASA, with the result that formal Assessment Studies are scheduled to begin in both agencies in October 1983.
Recent measurements of the spectrum and anisotropy of the cosmic microwave may be showing deviations from a perfectly homogeneous blackbody flux. Improved spectral measurements at wavelengths of 3 cm and 1.2 cm disagree weakly; and new results from a rocket show large excess flux at wavelengths of 0.71 and 0.48 mm. The same instrument measured a radiation temperature at λ = 1.16 mm of 2.795 ± 0.018 K in good agreement with results at longer wavelengths. The observed excess flux at short wavelengths may be due to: local contaminants; dust emission from active galaxies at high redshift; or inverse Compton scattering of microwave photons from hot electrons at large redshift (Sunyaev-Zel'dovich effect). Anisotropy of ΔT/T = 3.7 × 10−5 has been reported on an angular scale of 8° at a wavelength of 3 cm. Measurements on a similar angular scale at λ = 6 cm (reported at this meeting) do not show the anisotropy at the flux level expected if Galactic emission were the source of the anisotropy at λ = 3 cm. The standard model has not yet predicted anisotropy this large at 8°, but without doubt it soon will. Long integrations with the Very Large Array at λ = 6 cm are showing resolved structures on angular scales of 15 to 30 arcseconds. Observations at another wavelength are needed to see if these are radio sources at high redshift or perturbations in the 2.77 K radiatoin.
Timing the arrival of optical pulses from NP 0532 is a potentially important tool for studying the physics of this fascinating object. However, there are some difficulties in interpreting the data in terms of physical models. Some progress has been made on understanding the largest effect – the pulsar braking mechanism. The glitch of late September, 1969 can be interpreted as the speed-up, and subsequent relaxation, of the rotation of a neutron star crust. An alternate explanation is that of a planet in an eccentric orbit. Both models fit the rather meager data near the event. A small sinusoidal effect is indicated in a relatively quiet period of the data.
CVD accounted for 27 % of all deaths in the UK in 2014, and was responsible for 1·7 million hospital admissions in 2013/2014. This condition becomes increasingly prevalent with age, affecting 34·1 and 29·8 % of males and females over 75 years of age respectively in 2011. The dysregulation of cholesterol metabolism with age, often observed as a rise in LDL-cholesterol, has been associated with the pathogenesis of CVD. To compound this problem, it is estimated by 2050, 22 % of the world's population will be over 60 years of age, in culmination with a growing resistance and intolerance to pre-existing cholesterol regulating drugs such as statins. Therefore, it is apparent research into additional therapies for hypercholesterolaemia and CVD prevention is a growing necessity. However, it is also imperative to recognise this complex biological system cannot be studied using a reductionist approach; rather its biological uniqueness necessitates a more integrated methodology, such as that offered by systems biology. In this review, we firstly discuss cholesterol metabolism and how it is affected by diet and the ageing process. Next, we describe therapeutic strategies for hypercholesterolaemia, and finally how the systems biology paradigm can be utilised to investigate how ageing interacts with complex systems such as cholesterol metabolism. We conclude by emphasising the need for nutritionists to work in parallel with the systems biology community, to develop novel approaches to studying cholesterol metabolism and its interaction with ageing.
We present an investigation of the halo dynamics of M31 using planetary nebulae velocities. We have performed on-band [OIII] and off-band continuum imaging for a 3.6 square degree area centred on M31 and follow-up spectroscopy for over 600 planetary nebulae candidates. In the future the halo mass will be measured and the mass distribution and velocity anisotropy will be constrained as a function of radius.
The results of a large radial velocity survey of the Draco and Ursa Minor dwarf spheroidal galaxies are presented. the velocity dispersion profiles of both objects are very similar: initially the dispersion increases with radius, while at radii approaching the outer limit of the stellar distribution we observe a sharp fall-off. We present the results of mass modeling based on these new data – the mass to light ratios are found to be about 400M⊙/L⊙. Evidence is also presented that the dark matter in the central regions of UMi has a core-like distribution. Finally, we demonstrate that the inner regions of UMi have not been affected by tides and discuss the implications of our data for MOdified Newtonian Dynamics (MOND).
A series of VLBI surveys of complete samples of radio sources selected at 5 GHz (Pearson & Readhead 1988, hereafter PR; Xu et al. 1995 and references therein) has revealed that ≃ 10% of the objects are “Compact Symmetric Objects” (CSOs), in which high-luminosity radio emission regions are seen on both sides of the center of activity on scales less than one kiloparsec (Phillips & Mutel 1982; Readhead et al. 1984; Conway et al. 1992; Wilkinson et al. 1994). In order to be sure that an object is a CSO, either the center of activity must be pinpointed (Taylor et al. 1996) or compelling morphological evidence of symmetric structure must be found.
The 2.7 K microwave background radiation provides a sensitive probe of the universe in the interesting, but poorly understood, epoch around z ˜ 1000. At this time (age ~ 10 yr) the universe has cooled to T ~ 4000 K, the plasma combines, Thomson scattering ceases, and matter and blackbody radiation decouple. Subsequently, the radiation freely propagates to us, carrying the imprint of temperature fluctuations on the z ~ 1000 surface. The temperature fluctuations could have been caused by primordial density fluctuations, anisotropy in the expansion of the universe, or inhomogeneity in the initial temperature distribution; the z = 1000 surface we see was not causally connected at the time the radiation was released. Interpretation of the anisotropy measurements is complicated by the possibility that the matter may have been reionized (e.g. by massive stars), so the radiation may have been rescattered, possibly as late as z ~ 7.
The Cosmic Background Explorer, launched November 18, 1989, has nearly completed its first full mapping of the sky with all three of its instruments: a Far Infrared Absolute Spectrophotometer (FIRAS) covering 0.1 to 10 mm, a set of Differential Microwave Radiometers (DMR) operating at 3.3, 5.7, and 9.6 mm, and a Diffuse Infrared Background Experiment (DIRBE) spanning 1 to 300 µm in ten bands. A preliminary map of the sky derived from DIRBE data is presented. Initial cosmological implications include: a limit on the Comptonization y parameter of 10−3, on the chemical potential μ parameter of 10−2, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy has the spectrum expected from a Doppler shift of a blackbody. There are no significant anisotropies in the microwave sky detected, other than from our own galaxy and a cosθ dipole anisotropy whose amplitude and direction agree with previous data. At shorter wavelengths, the sky spectrum and anisotropies are dominated by emission from ‘local’ sources of emission within our Galaxy and Solar System. Preliminary comparison of IRAS and DIRBE sky brightnesses toward the ecliptic poles shows the IRAS values to be significantly higher than found by DIRBE at 100 μm. We suggest the presence of gain and zero-point errors in the IRAS total brightness data. The spacecraft, instrument designs, and data reduction methods are described.
The Collaboration of Australia and Nippon for a GAmma Ray Observatory in the Outback operates two large telescopes at Woomera (South Australia), which detect the Čerenkov light images produced in the atmosphere by electronpositron cascades initiated by very high energy (~1 TeV or 1012 eV) gamma rays. These gamma rays arise from a different mechanism than at EGRET energies: inverse Compton (IC) emission from relativistic electrons.
The spoke-like images are recorded by a multi-pixel camera which facilitates the rejection of the large numbers of oblique and ragged cosmic ray images. A field of view ~3.5° is required. The Australian team operates a triple 4 m diameter mirror telescope, BIGRAT, with a 37 photomultiplier tube camera and energy threshold 600 GeV. The Japanese operate a single, highly accurate 3.8 m diameter f/1 telescope and high resolution 256 photomultipler tube camera. In 1998 a new 7 m telescope is planned for Woomera with a design threshold ~;200GeV.
To identify predictive factors and mortality of patients with influenza admitted to intensive care units (ICU) we carried out a prospective cohort study of patients hospitalized with laboratory-confirmed influenza in adult ICUs in a network of Canadian hospitals between 2006 and 2012. There were 626 influenza-positive patients admitted to ICUs over the six influenza seasons, representing 17·9% of hospitalized influenza patients, 3·1/10 000 hospital admissions. Variability occurred in admission rate and proportion of hospital influenza patients who were admitted to ICUs (proportion range by year: 11·7–29·4%; 21·3% in the 2009–2010 pandemic). In logistic regression models ICU patients were younger during the pandemic and post-pandemic period, and more likely to be obese than hospital non-ICU patients. Influenza B accounted for 14·2% of all ICU cases and had a similar ICU admission rate as influenza A. Influenza-related mortality was 17·8% in ICU patients compared to 2·0% in non-ICU patients.
The mean air temperature of the Icelandic interior is below 10 °C. However, we have previously observed 16S rDNA sequences associated with thermophilic lineages in Icelandic basalts. Measurements of the temperatures of igneous rocks in Iceland showed that solar insolation of these low albedo substrates achieved a peak surface temperature of 44.5 °C. We isolated seven thermophilic Geobacillus species from basalt with optimal growth temperatures of ~65 °C. The minimum growth temperature of these organisms was ~36 °C, suggesting that they could be active in the rock environment. Basalt dissolution rates at 40 °C were increased in the presence of one of the isolates compared to abiotic controls, showing its potential to be involved in active biogeochemistry at environmental temperatures. These data raise the possibility of transient active thermophilic growth in macroclimatically cold rocky environments, implying that the biogeographical distribution of active thermophiles might be greater than previously understood. These data show that temperatures measured or predicted over large scales on a planet are not in themselves adequate to assess niches available to extremophiles at micron scales.
This, the second report on the activities of a team from the British Archaeological Expedition to Iraq in the north Jazira, will present an overview of the results of the first four seasons of fieldwork. A review of settlement change since the first millennium BC will be reserved for a future publication. The first two seasons of survey (autumn 1986 and 1987), which concentrated on the region around Tell al-Hawa, were followed, in autumn 1988, by a season of excavation of three sites within the hinterland: Tulul al-Biyadir, Tell al-Hilwa and Khanijdal. The most recent season, conducted over some four months between September 1989 and February 1990, resulted in a total survey coverage of some 475 sq km. In addition, a single Late Assyrian/Hellenistic/Parthian site (Khirbet ‘Aloki) was excavated to investigate the sequence of settlement within the area of putative Neo-Assyrian colonisation. The first interim report (Ball, Tucker and Wilkinson 1989, henceforth, Ball et al. 1989) presented an introduction to the area and the rescue project; this report will focus upon the development of settlement and the influence that early route systems had upon settlement patterns.
Members of the British Archaeological Expedition to Iraq first visited Tell al-Hawa in January 1986 from the Saddam Dam. The site appears as a massive, solitary giant, dominating the landscape and dwarfing all other sites in the region (Plate Ia). From the summit, 30 m high, there is an impressive view over a vast plain covered with mounds in all directions. A walk over the main mound revealed a particularly wide range of pottery types representing most known periods. The size, scope and archaeological potential of Tell al-Hawa and the surrounding plain led us to decide on further investigation.
A first season of survey and excavations was conducted from October 1986 to April 1987 inclusive. The aim of the project was to carry out a single, integrated study of a major site in its context.
We would like to thank specially Dr Mu'ayyad Sa'id Damerji, the Director-General of Antiquities and Heritage, and Dr Abd as-Sittar Azzawi, then Director of the Antiquities Office in the North, without whose help the Hawa Project would not have been possible. For the duration of the 1987 season we were allowed use of Antiquities Office housing and working facilities in the citadel at Tel'afar, for which we are very grateful. Mr Salem Yunis, then Inspector at Tel'afar, was of considerable assistance to us at all times, as were our representatives in the field, Mr Mohammed Zaki Abdul Kerim and Mr Meti Barbar al-Tumm.