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The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course of Earth’s history. It reviews how the geochemistry of diamonds and their inclusions inform us about the deep carbon cycle, the origin of the diamonds in Earth’s mantle, and the evolution of diamonds through time.
With the recent discovery of a dozen dusty star-forming galaxies and around 30 quasars at z > 5 that are hyper-luminous in the infrared (μ LIR > 1013 L⊙, where μ is a lensing magnification factor), the possibility has opened up for SPICA, the proposed ESA M5 mid-/far-infrared mission, to extend its spectroscopic studies toward the epoch of reionisation and beyond. In this paper, we examine the feasibility and scientific potential of such observations with SPICA’s far-infrared spectrometer SAFARI, which will probe a spectral range (35–230 μm) that will be unexplored by ALMA and JWST. Our simulations show that SAFARI is capable of delivering good-quality spectra for hyper-luminous infrared galaxies at z = 5 − 10, allowing us to sample spectral features in the rest-frame mid-infrared and to investigate a host of key scientific issues, such as the relative importance of star formation versus AGN, the hardness of the radiation field, the level of chemical enrichment, and the properties of the molecular gas. From a broader perspective, SAFARI offers the potential to open up a new frontier in the study of the early Universe, providing access to uniquely powerful spectral features for probing first-generation objects, such as the key cooling lines of low-metallicity or metal-free forming galaxies (fine-structure and H2 lines) and emission features of solid compounds freshly synthesised by Population III supernovae. Ultimately, SAFARI’s ability to explore the high-redshift Universe will be determined by the availability of sufficiently bright targets (whether intrinsically luminous or gravitationally lensed). With its launch expected around 2030, SPICA is ideally positioned to take full advantage of upcoming wide-field surveys such as LSST, SKA, Euclid, and WFIRST, which are likely to provide extraordinary targets for SAFARI.
We performed a new series of measurements on samples that were part of early measurements on radiocarbon (14C) dating made in 1948–1949. Our results show generally good agreement to the data published in 1949–1951, despite vast changes in technology, with only two exceptions where there was a discrepancy in the original studies. Our new measurements give calibrated ages that overlap with the known ages. We dated several samples at four different laboratories, and so we were also able to make a small intercomparison at the same time. In addition, new measurements on samples from other Egyptian materials used by Libby and co-workers were made at UC Irvine. Samples of tree rings used in the original studies (from Broken Flute Cave and Centennial Stump) were obtained from the University of Arizona Laboratory of Tree-Ring Research archive and remeasured. New data were compared to the original studies and other records.
In sub-Saharan Africa (SSA), the association of crops and livestock in mixed farming systems generally benefits both enterprises. This paper focuses on the main contributions of livestock to crop production: the use of manure and animal draught power to produce crops and the investment of income from livestock into technologies that benefit crop production. In low-input, grazing-based feeding operations, manure is a vital soil fertility amendment. In these systems, penning livestock overnight on fields, fallow between cropping periods, returns both manure and urine to the soil and results in much higher crop yields than if manure only is gathered from stalls and spread onto fields. However, most farmers have insufficient manure to sustain food production. Nutrient harvests often exceed nutrient inputs, requiring a much greater use of fertilizers to arrest soil nutrient depletion. The opposite may be true for mixed farming where livestock are given food in confinement. In these emerging systems, the continuous importation of food (and fertilizer) can result in nutrient surpluses with subsequent soil nutrient build-up and loss. The contribution of animal power to crop production is relatively new in Africa. Animal power affects the amount of land cultivated by farmers, crop selection, the yield per farm and per ha, and on the participation and work load of people (family members and outside labour) involved in crop production and its associated activities. In addition to the impacts of manure and draught power on crop production, income derived from livestock is often invested in inputs that enhance crop production. At the ‘micro’ level, livestock income influences crop production (1) directly by allowing households to invest in productive inputs such as fertilizer, hired labour, and carts and (2) indirectly by allowing poor households to improve their nutritional status and, therefore, the productivity of their most important resource, their own labour. At the ‘macro’ level, increased livestock exports have a large stimulating effect on the demand for locally produced goods and services, particularly basic food crops. Thus, increasing the productivity of the livestock sector, including an emphasis on the policy and institutional environment influencing marketing and trade, is an important element of a development strategy focused on stimulating economic growth and alleviating poverty.
Our current knowledge of star formation and accretion luminosity at high redshift (z > 3–4), as well as the possible connections between them, relies mostly on observations in the rest-frame ultraviolet, which are strongly affected by dust obscuration. Due to the lack of sensitivity of past and current infrared instrumentation, so far it has not been possible to get a glimpse into the early phases of the dust-obscured Universe. Among the next generation of infrared observatories, SPICA, observing in the 12–350 µm range, will be the only facility that can enable us to trace the evolution of the obscured star-formation rate and black-hole accretion rate densities over cosmic time, from the peak of their activity back to the reionisation epoch (i.e., 3 < z ≲ 6–7), where its predecessors had severe limitations. Here, we discuss the potential of photometric surveys performed with the SPICA mid-infrared instrument, enabled by the very low level of impact of dust obscuration in a band centred at 34 µm. These unique unbiased photometric surveys that SPICA will perform will fully characterise the evolution of AGNs and star-forming galaxies after reionisation.
A new snow—soil—vegetation—atmosphere transfer (Snow-SVAT) scheme, which simulates the accumulation and ablation of the snow cover beneath a forest canopy, is presented. The model was formulated by coupling a canopy optical and thermal radiation model to a physically based multi-layer snow model. This canopy radiation model is physically based yet requires few parameters, so can be used when extensive in situ field measurements are not available. Other forest effects such as the reduction of wind speed, interception of snow on the canopy and the deposition of litter were incorporated within this combined model, SNOWCAN, which was tested with data taken as part of the Boreal Ecosystem—Atmosphere Study (BOREAS) international collaborative experiment. Snow depths beneath four different canopy types and at an open site were simulated. Agreement between observed and simulated snow depths was generally good, with correlation coefficients ranging between r2 = 0.94 and r2 = 0.98 for all sites where automatic measurements were available. However, the simulated date of total snowpack ablation generally occurred later than the observed date. A comparison between simulated solar radiation and limited measurements of sub-canopy radiation at one site indicates that the model simulates the sub-canopy downwelling solar radiation early in the season to within measurement uncertainty.
The Square Kilometre Array will be an amazing instrument for pulsar astronomy. While the full SKA will be sensitive enough to detect all pulsars in the Galaxy visible from Earth, already with SKA1, pulsar searches will discover enough pulsars to increase the currently known population by a factor of four, no doubt including a range of amazing unknown sources. Real time processing is needed to deal with the 60 PB of pulsar search data collected per day, using a signal processing pipeline required to perform more than 10 POps. Here we present the suggested design of the pulsar search engine for the SKA and discuss challenges and solutions to the pulsar search venture.
Very Long Baseline Interferometry at radio wavelengths is the only technique available for imaging the central few parsecs of powerful radio galaxies and quasars. VLBI observations have shown that in many nuclei radio-emitting material is collimated into a jet on a scale less than a parsec and ejected at relativistic velocities. The interpretation of the observations is complicated by the relativistic motion, however: the images are dominated by those parts of the source that are moving almost directly towards the observer, and thus amplified by relativistic aberration. Nonetheless, the VLBI images are vital for understanding the nature of the central engine, the cause of the collimation, and the physics of the jets.
Five objects mapped as part of a VLBI survey have been re-observed at 5 GHz, and four of them have also been observed at 10 GHz. Three of the objects show no substantial structural variations: an upper limit of 2c can be placed on the apparent relative velocities of the components. One object (0711+356) shows structural variations which are mostly simply described in terms of a superluminal contraction. The remaining object (3C371, 1807+698) shows substantial structural variations which suggest that it probably is a superluminal source. The source 0710+439 is especially interesting as it consists of a central flat-spectrum core component straddled by two compact steep-spectrum components.
We have conducted a systematic study of the milliarcsecond structure of a complete, flux-density limited sample of strong radio sources selected at 5 GHz. We have made 5 GHz maps at two epochs of the 45 compact sources in the sample, and third-epoch observations are in progress. Our intention was to explore the full range of morphologies exhibited by compact radio sources, to search for new superluminal sources, and to determine how widespread such phenomena as parsec-scale jets, alignment of parsec-scale and kiloparsec-scale jets, and superluminal motion are. In addition, we hoped to use this well-defined sample for statistical tests of the beaming theories.
Elevated birth weight is linked to glucose intolerance and obesity health-related complications later in life. No studies have examined if infant birth weight is associated with gene expression markers of obesity and inflammation in a tissue that comes directly from the infant following birth. We evaluated the association between birth weight and gene expression on fetal programming of obesity. Foreskin samples were collected following circumcision, and gene expression analyzed comparing the 15% greatest birth weight infants (n=7) v. the remainder of the cohort (n=40). Multivariate linear regression models were fit to relate expression levels on differentially expressed genes to birth weight group with adjustment for variables selected from a list of maternal and infant characteristics. Glucose transporter type 4 (GLUT4), insulin receptor substrate 2 (IRS2), leptin receptor (LEPR), lipoprotein lipase (LPL), low-density lipoprotein receptor-related protein 1 (LRP1), matrix metalloproteinase 2 (MMP2), plasminogen activator inhibitor-1 (PAI-1) and transcription factor 7-like 2 (TCF7L2) were significantly upregulated and histone deacetylase 1 (HDAC1) and thioredoxin (TXN) downregulated in the larger birth weight neonates v. controls. Multivariate modeling revealed that the estimated adjusted birth weight group difference exceeded one standard deviation of the expression level for eight of the 10 genes. Between 25 and 50% of variation in expression level was explained by multivariate modeling for eight of the 10 genes. Gene expression related to glycemic control, appetite/energy balance, obesity and inflammation were altered in tissue from babies with elevated birth weight, and these genes may provide important information regarding fetal programming in macrosomic babies.
Since 1977 we have been engaged on a project to survey the milliarcsecond structure and internal motions of a complete, unbiased sample of 65 radio sources (Pearson and Readhead 1984). One of the goals of the project was to discover more superluminal sources and find out how common they are. The sample contains three established superluminal sources (3C 179, 3C 345, and BL Lacertae); so far we have discovered three new superluminal quasars (0850+581, 1642+690, and 1928+738), and a fourth (3C 216) that may be superluminal. Thus at least six out of the 65 sources are superluminal, and we expect to find more as our observations proceed.
Increasing concern with nuclear waste isolation technology is leading to additional studies of naturally occurring isotopes in ground water. Such studies provide information on 1) the use of radionuclides to estimate ground-water travel times and/or residence times. This information can he an extremely useful adjunct to conventional hydrologic data in developing the understanding of regional hydrology needed in the site selection process, and 2) the use of natural radionuclides as analogues to the behavior of radionuclides of concern in nuclear waste.
The Cosmic Background Imager (CBI) is an instrument designed to make images of the cosmic microwave background radiation and to measure its statistical properties on angular scales from about 3 arc minutes to one degree (spherical harmonic scales from l ˜ 4250 down to l ˜ 400). The CBI is a 13-element interferometer mounted on a 6 meter platform operating in ten 1-GHz frequency bands from 26 GHz to 36 GHz. The instantaneous field of view of the instrument is 45 arcmin (FWHM) and its resolution ranges from 3 to 10 arcmin; larger fields can be imaged by mosaicing. At this frequency and resolution, the primary foreground is due to discrete extragalactic sources, which are monitored at the Owens Valley Radio Observatory and subtracted from the CBI visibility measurements.
The instrument has been making observations since late 1999 of both primordial CMB fluctuations and the Sunyaev-Zeldovich effect in clusters of galaxies from its site at an altitude of 5080 meters near San Pedro de Atacama, in northern Chile. Observations will continue until August 2001 or later. We present preliminary results from the first few months of observations.
We report the direct detection of cyclic diameter variations in the Mira variable χ Cygni. Interferometric observations made between 1997 July and 1998 September, using the Cambridge Optical Aperture Synthesis Telescope (COAST) indicate periodic changes in the apparent angular diameter with amplitude 45 per-cent of the smallest value.
The measurements were made in a 50 nm bandpass centred on 905 nm, which is only moderately contaminated by molecular absorption features. To assess the effects of atmospheric stratification on the apparent diameter measured in this band, we have also measured near-infrared diameters for a sample of five Miras, in both the J-band (1.3 μm) and Wing's (1971) 1.04 μm band, which is expected to isolate essentially pure continuum emission. We present J-band visibility curves which indicate that the intensity profiles of the stars in the sample differ greatly from each other.
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.
We are using the VSOP space VLBI mission to observe a complete sample of Pearson-Readhead survey sources at 4.8 GHz to determine core brightness temperatures and pc-scale jet properties. To date we have imaged 27 of the 31 objects in our sample. Our preliminary results show that the majority of objects contain strong core components that remain unresolved on baselines of 30,000 km. The brightness temperatures of several cores significantly exceed 1012 K, which is indicative of highly relativistically beamed emission. We also find that core brightness temperature is correlated with intraday variability in compact AGNs.