We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to .
To send content items to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
Decision-makers need readily accessible tools to understand the potential impacts of alternative policies on forest cover and greenhouse gas (GHG) emissions and to develop effective policies to meet national and international targets for biodiversity conservation, sustainable development and climate change mitigation. Land change modelling can support policy decisions by demonstrating potential impacts of policies on future deforestation and GHG emissions. We modelled land change to explore the potential impacts of expert-informed scenarios on deforestation and GHG emissions, specifically CO2 emissions, in the Ankeniheny–Zahamena Corridor in eastern Madagascar. We considered four scenarios: business as usual; effective conservation of protected areas; investment in infrastructure; and agricultural intensification. Our results highlight that effective forest conservation could deliver substantial emissions reductions, while infrastructure development will likely cause forest loss in new areas. Agricultural intensification could prevent additional forest loss if it reduced the need to clear more land while improving food security. Our study demonstrates how available land change modelling tools and scenario analyses can inform land-use policies, helping countries reconcile economic development with forest conservation and climate change mitigation commitments.
Detection of individual modes of oscillation near 5 minutes period is proposed, based on the comb-like signature which is similar to that found in the sun. The mean peak amplitudes (ap) of the strongest individual modes are 75 ≤ ap ≤ 120 cm/s, and the mean separation between alternate modes is 55.3 ± 3.6 μHz. Apparent modal lifetimes are on the order of 2 days, but we suggest this may be caused by interference of adjacent modes.
Over the past several years a considerable body of evidence has accumulated, suggesting that extended radio sources are powered quasi-continuously from the nuclei of their parent galaxies. This view is supported by the recent discovery that several radio galaxies have narrow radio jets which connect their active nuclei with the large radio lobes and which often extend for several tens of kiloparsecs. Because of their presumed association with the energy transport outward from the active nuclei, radio jets are at present being intensively studied with high-resolution radio techniques.
The closest galaxy known to have a radio jet is the giant elliptical M87 (e.g., Wilkinson 1974), and in this case there is a well-known optical counterpart (e.g., Curtis 1918; de Vaucouleurs, Angione and Fraser 1968), This optical jet is highly polarized (Baade 1956), implying that at least part of the emission is non-thermal. This and the good agreement between the optical and radio structure suggests that these features are closely related.
Massive stars are some of the most important objects in the Universe, shaping the evolution of galaxies, creating chemical elements, and hence shaping the evolution of the Universe. However, the processes by which they form, and how they shape their environment during their birth processes, are not well understood. We are using NH3 data from the “The H2O Southern Galactic Plane Survey” (HOPS) to define the positions of dense cores/clumps of gas in the southern Galactic plane that are likely to form stars. We did a comparative study with different methods for finding clumps and found Fellwalker to be the best for this dataset. We detected ~ 500 clumps with mean kinetic temperature ~ 20 K and virial mass ~ 680 solar masses.
Although Europeans had been receiving reports about Buddhism since the thirteenth century – from Marco Polo, papal envoys, Jesuits, and Asian specialists – it was not until the midcentury that European intellectuals generally began to be aware that there was at least one major form of religion, Theravada Buddhism, which was atheistic. Nevertheless, the general tendency throughout the century was to conceive of the “essence of religion” as belief in supernatural deities and to regard monotheism as the most highly developed form of it. Consequently, most of the challenges to religion in the nineteenth century, like those in the seventeenth and eighteenth, tended to be challenges to theism generally and to the culturally predominant forms of it, Christianity and Judaism, particularly. And it will be these challenges with which we shall be primarily concerned.
What distinguishes the nineteenth from previous centuries is the extraordinary variety of these challenges. The attacks of the seventeenth and eighteenth centuries were primarily philosophical and rationalistic, and the arguments swirled around such age-old issues as the cogency of the arguments for the existence of God, the possibility of miracles, and whether the existence of evil is compatible with the reality of an omnipotent and benevolent deity. But the challenges to religion in the nineteenth century were launched not only by philosophers but by political revolutionaries, liberal reformers, utilitarian moralists, positivistic social theorists, agnostics, and a variety of scholars working in the new specialized and increasingly professionalized forms of knowledge: anthropology, biology, geology, history, psychology, and sociology.
Objective: Depression is suggested to involve disturbances in cholinergic as well as glutamatergic pathways, particularly the N-methyl-d-aspartate receptor-mediated release of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP). The aim of this study was to determine whether the Flinders Sensitive Line (FSL) rat, a genetic model of depression, presents with corticolimbic changes in basal acetylcholine (ACh) levels and NO/cGMP signalling.
Methods: Basal levels of nitrogen oxides (NOx) and both basal and l-arginine-stimulated nitric oxide synthase (NOS) formation of l-citrulline were analysed in hippocampus and frontal cortex in FSL and control Flinders resistant line (FRL) rats by fluorometric and electrochemical high-performance liquid chromatography, respectively. In addition, ACh and cGMP levels were analysed by liquid chromatography tandem mass spectrometry and radioimmunoassay, respectively.
Results: Significantly elevated frontal cortical but reduced hippocampal ACh levels were observed in FSL versus FRL rats. Basal cGMP levels were significantly reduced in the frontal cortex, but not hippocampus, of FSL rats without changes in NOx and l-citrulline, suggesting that the reduction of cGMP follows through an NOS-independent mechanism.
Conclusions: These data confirm a bidirectional change in ACh in the frontal cortex and hippocampus of the FSL rat, as well as provide evidence for a frontal cortical ACh-cGMP interaction in the depressive-like behaviour of the FSL rat.
The radiation damage properties of synthetic pyrochlore-defect fluorite compounds containing lanthanides on the A-site and Ti, Zr, Sn, and Hf on the B-site have been studied extensively using Kr ion irradiation. Using statistical analysis, we show that the results can be quantified in terms of the critical temperature for amorphization, structural parameters, classical Pauling electronegativity difference, and defect energies. The best current model is able to predict the critical temperature to within about 80 degrees Kelvin. The model indicates that radiation tolerance is correlated with an increase in the X anion coordinate toward the value characteristic of the defect fluorite topology, a smaller unit cell dimension, and lower defect energies. Our analysis also demonstrates that radiation tolerance is promoted by an increase in the Pauling cation-anion electronegativity difference or, in other words, an increase in the ionicity of the chemical bonds. Of the two possible cation sites in ideal pyrochlore, the B-site cation appears to play the major role in bonding. This result is supported, for a subset of pyrochlore compounds, by ab initio calculations, which reveal a correlation between the Mulliken overlap populations of the B-site cation and the critical temperature.
The structural characteristics of samples in the (Y1−xLax)2Ti2O7 system have been studied as a function of bulk composition using time-of-flight (TOF) powder neutron diffraction, powder X-ray diffraction (XRD), Electron Microscopy and 89Y (I = ½) Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR). Analysis of the neutron diffraction data suggests the following: For compositions where 0 ≤ x ≤ 0.132, a single cubic phase is present (Fd3, m, Z = 8). Between 0.832 ≤ − ≤ 1, a solid solution with the La2Ti2O7 structure (P21, Z = 4) forms. The two phases coexist between x values of 0.132 and 0.832. XRD suggests that the limits of the two regions of solid solution fall within the ranges of x = 0.1-0.125 and x = 0.875-0.9. The variation in the limits found by the two diffraction methods may be due to stoichiometric errors in the samples. Line-shape analysis of NMR spectra for Y rich compositions suggests that increasing proportions of La are incorporated onto the pyrochlore A site in a statistically random manner, up to the limit of solid solution. The NMR spectra of the monoclinic phase suggest that occupation of the four crystallographically distinct ‘A’ type sites within the structure is not random. At low Y concentrations, two of these sites are preferentially occupied by Y. These sites are suggested to be those found at the edge of the perovskite slabs, which exhibit smaller coordination numbers (based on the number of oxygens within bonding distance of the ‘A’ type cation) than the true perovskite A sites found at the slab centres.
We report a study of dynamic cracking of a silicon single crystal in which the ReaxFF reactive force field is used for about 3,000 atoms near the crack tip while the other 100,000 atoms of the model system are described with a simple nonreactive force field. The ReaxFF is completely derived from quantum mechanical calculations of simple silicon systems without any empirical parameters. This model has been successfully used to study crack dynamics in silicon, capable of reproducing key experimental results such as orientation dependence of crack dynamics (Buehler et al., Phys. Rev. Lett., 2006). Here we focus on crack speeds as a function of loading and crack propagation mechanisms. We find that the steady state crack speed does not increase continuously with applied load, but instead jumps to a finite value immediately after the critical load, followed by a regime of slow increase. Our results quantitatively reproduce experimental observations of crack speeds during fracture in silicon along the (111) planes, confirming the existence of lattice trapping effects. We find that the underlying reason for this behavior is formation of a 5-7-double ring defect at the tip of the crack, effectively hindering nucleation of the crack at the Griffith load. We develop a simple continuum model that explains the qualitative behavior of the fracture dynamics.
We report a study of dynamic cracking in a silicon single crystal in which the ReaxFF reactive force field is used for about 3,000 atoms near the crack tip while the other 100,000 atoms of the model system are described with a simple nonreactive force field. The ReaxFF is completely derived from quantum mechanical calculations of simple silicon systems without any empirical parameters. This model has been successfully used to study crack dynamics in silicon, capable of reproducing key experimental results such as orientation dependence of crack dynamics (Buehler et al., Phys. Rev. Lett., 2006). In this article, we focus on crack speeds as a function of loading and crack propagation mechanisms. We find that the steady state crack speed does not increase continuously with applied load, but instead jumps to a finite value immediately after the critical load, followed by a regime of slow increase. Our results quantitatively reproduce experimental observations of crack speeds during fracture in silicon along the (111) planes, confirming the existence of lattice trapping effects. We observe similar effects in the (110) crack direction.
Poor diet in childhood increases risk of obesity but the relationship between access to food and children’s food choice is underexplored. We determined relationships between distance to and density of food outlets on children’s food choice.
Children (n 1721) aged 9–10 years who participated in a cross-sectional study from a sample of state and private schools across urban and rural areas. Food consumption was reported using a short validated FFQ. A Geographic Information System was used to determine proximity to local food outlets. Multivariable regression analyses were performed to determine associations between food consumption and distance to and density of local food outlets.
Norfolk, England.
Boys (n 754) and girls (n 967) aged 9–10 years.
The impact of distance to or density of food outlets on food choice was small after adjustment. Living further away from a supermarket increased portions of fruit (0·11 portions/week per 1 km increase in distance to nearest supermarket, P < 0·05) and vegetables (0·11 portions/week, P < 0·05) consumed. Living closer to convenience stores was also associated with an increased consumption of crisps, chocolate and white bread. Density of supermarkets was associated with both an increase in vegetable intake (0·31 portions/week, P < 0·05) and unhealthy foods.
Distance to and density of food outlets are both associated with children’s food choice, although the impact appears to be small and the relationship is complex. However, the effects of individual foods combined could be important, particularly as even small differences in intake can impact on body weight over time.
Ludwig Feuerbach (1804–72) was the fourth of eight children in one of the most distinguished German families of the time. Deeply religious as a youth, he entered Heidelberg in 1823 in order to study Christian theology. But there he came under the influence of a well-known Hegelian theologian. Impressed by the intellectual grandeur of Hegelianism he decided to transfer to Berlin where Hegel taught, although he gave his father the impression that he wanted to study theology with the famous Protestant theologian Friedrich Schleiermacher. Because of financial reasons, he transferred to Erlangen in 1826 where, after completing his dissertation, he was made a Privatdozent. There he lectured on the history of modern philosophy.
In 1830 and against the advice of his father, he published anonymously a book entitled Thoughts on Death and Immortality, which argued that the most authentic religious faith would not contain the traditional Christian beliefs in a personal God and in personal immortality. The text, unfortunately, was accompanied by a series of derogatory epigrams directed against pietism. The book was censored by the authorities and Feuerbach was fired from the university. He married in 1837 but, unable to find academic employment, retired to a remote village near Ansbach where his wife's father owned a porcelain factory. There, in relative isolation except for trips to visit friends, he devoted his life to writing. The youngest of his two daughters died a very painful death aged three and Feuerbach never recovered from what he regarded as the senseless death of this infant.
LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30–240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient buffering makes retrospective imaging of explosive short-term events possible. The scientific focus of LOFAR will initially be on four key science projects (KSPs): (i) Detection of the formation of the very first stars and galaxies in the universe during the so-called epoch of reionization by measuring the power spectrum of the neutral hydrogen 21-cm line (Shaver et al. 1999) on the ∼ 5′ scale; (ii) Low-frequency surveys of the sky with of order 108 expected new sources; (iii) All-sky monitoring and detection of transient radio sources such as γ-ray bursts, X-ray binaries, and exo-planets (Farrell et al. 2004); and (iv) Radio detection of ultra-high energy cosmic rays and neutrinos (Falcke & Gorham 2003) allowing for the first time access to particles beyond 1021 eV (Scholten et al. 2006). Apart from the KSPs open access for smaller projects is also planned. Here we give a brief description of the telescope.
Email your librarian or administrator to recommend adding this to your organisation's collection.