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A method is described for the least-squares refinement of the atomic parameters of the ordered part of a crystal structure in the presence of disordered solvent areas. Potential solvent regions are identified automatically. The contribution of the observed contents to the total structure factor is calculated via a discrete Fourier transformation, and incorporated in a further least-squares refinement of the ordered part of the structure. The procedure is iterated a few times to convergence. It is found that this mixed discrete-atom and continuous solvent-area model refinement approach greatly improves the quality of discrete atomic parameters, i.e. the geometry and the e.s.d.'s. An electron count over the solvent region in the final difference electron-density map provides a convenient estimate for the number of solvent molecules present in the unit cell. The application of the method to four structures is described.

The importance and abundance of cryptic species among invertebrate taxa is well documented. Nowadays, taxonomic, phylogenetic and conservation biological studies frequently use molecular markers to delineate cryptic taxa. Such studies, however, often face the problem of the differential resolution of the molecular markers and techniques involved. This issue is explored in the present study of cryptic taxa within the terrestrial slug complex Arion subfuscus/fuscus in continental north-west Europe. To this end, morphological, allozyme and mitochondrial 16S rDNA sequence data have been jointly evaluated. Using allozyme data and gonad type, two distinct groups were consistently delineated, even under sympatric conditions. The 16S rDNA data strongly supported both those groups and even suggested the presence of three distinct taxa within one of them. However, in view of: (1) the allopatric distribution of three OTUs, (2) the lack of allozyme or morphological differentiation, and (3) the extremely high degree of intraspecific mtDNA variation reported in pulmonate gastropods, they are, for the time being, not regarded as valid species under the biological species concept. By means of 16S rDNA and allozyme data, the position of type and topotype material of A. subfuscus s.s. and A. fuscus relative to the newly defined OTUs was determined, thus clarifying the nomenclature of this species complex. Additionally, gonad type proved to be a useful character for distinguishing the two species in north-west Europe.

Abstract “…. For the truth of the conclusions of physical science, observation is the supreme Court of Appeal….” (Sir Arthur Eddington, The Philosophy of Physical Science.) In this paper we shall review the theoretical and experimental results obtained on simple magnetic model systems. We shall consider the Heisenberg, XY and Ising type of interaction (ferro and antiferromagnetic), on magnetic lattices of dimensionality 1, 2 and 3. Particular attention will be paid to the approximation of these model systems in real crystals, viz. how they can be realized or be expected to exist in nature. A large number of magnetic compounds which, according to the available experimental information, meet the requirements set by one or the other of the various models are considered and their properties discussed. Many examples will be given that demonstrate to what extent experiments on simple magnetic systems support theoretical descriptions of magnetic ordering phenomena and contribute to their understanding. It will also be indicated in which direction there is a need and/or a possibility for future work.

Traditional approaches to neural coding characterize the encoding of known stimuli in average neural responses. Organisms face nearly the opposite task--extracting information about an unknown time-dependent stimulus from short segments of a spike train. Here the neural code was characterized from the point of view of the organism, culminating in algorithms for real-time stimulus estimation based on a single example of the spike train. These methods were applied to an identified movement-sensitive neuron in the fly visual system. Such decoding experiments determined the effective noise level and fault tolerance of neural computation, and the structure of the decoding algorithms suggested a simple model for real-time analog signal processing with spiking neurons.

The Infrared Astronomical Satellite (IRAS) consists of a spacecraft and a liquid helium cryostat that contains a cooled IR telescope. The telescope's focal plane assembly is cooled to less than 3 K, and contains 62 IR detectors in the survey array which are arranged so that every source crossing the field of view can be seen by at least two detectors in each of four wavelength bands. The satellite was launched into a 900 km-altitude near-polar orbit, and its cryogenic helium supply was exhausted on November 22, 1983. By mission's end, 72 percent of the sky had been observed with three or more hours-confirming scans, and 95 percent with two or more hours-confirming scans. About 2000 stars detected at 12 and 25 microns early in the mission, and identified in the SAO (1966) catalog, have a positional uncertainty ellipse whose axes are 45 x 9 arcsec for an hours-confirmed source.

The intermetallic compound U${\mathrm{Ru}}_{2}$${\mathrm{Si}}_{2}$ can be classified as a heavy-fermion system because of its large linear specific-heat coefficient $\ensuremath{\gamma}=180$ mJ/mol\ifmmode\cdot\else\textperiodcentered\fi{}${\mathrm{K}}^{2}$. Susceptibility, magnetization, and specific-heat measurements on single-crystal samples indicate both a magnetic phase transition at 17.5 K and a superconducting transition at 0.8 K. The magnetic and superconducting properties are highly anisotropic.

Crisis management has become a defining feature of contemporary governance. In times of crisis, communities and members of organizations expect their leaders to minimize the impact of the crisis at hand, while critics and bureaucratic competitors try to seize the moment to blame incumbent rulers and their policies. In this extreme environment, policy makers must somehow establish a sense of normality, and foster collective learning from the crisis experience. In this uniquely comprehensive analysis, the authors examine how leaders deal with the strategic challenges they face, the political risks and opportunities they encounter, the errors they make, the pitfalls they need to avoid, and the paths away from crisis they may pursue. This book is grounded in over a decade of collaborative, cross-national case study research, and offers an invaluable multidisciplinary perspective. This is an original and important contribution from experts in public policy and international security.

Pupils respond to three distinct kinds of stimuli: they constrict in response to brightness (the pupil light response), constrict in response to near fixation (the pupil near response), and dilate in response to increases in arousal and mental effort, either triggered by an external stimulus or spontaneously. In this review, I describe these three pupil responses, how they are related to high-level cognition, and the neural pathways that control them. I also discuss the functional relevance of pupil responses, that is, how pupil responses help us to better see the world. Although pupil responses likely serve many functions, not all of which are fully understood, one important function is to optimize vision either for acuity (small pupils see sharper) and depth of field (small pupils see sharply at a wider range of distances), or for sensitivity (large pupils are better able to detect faint stimuli); that is, pupils change their size to optimize vision for a particular situation. In many ways, pupil responses are similar to other eye movements, such as saccades and smooth pursuit: like these other eye movements, pupil responses have properties of both reflexive and voluntary action, and are part of active visual exploration.

Distributional analyses and event-related brain potential were used to show that effects of irrelevant spatial stimulus-response correspondence consist of 2 qualitatively different automatic components that can be distinguished on the basis of their dependencies on relative response speed and on computational requirements of the primary task. One component reflects priming of the spatially corresponding response by an abrupt stimulus onset that does not depend on the nature of the primary task. This unconditional component exhibits a biphasic pattern, with initial facilitation later turning into inhibition, analogous to that found for spatial cuing in visual detection tasks. The 2nd component reflects automatic generalization of task-defined transformations of relevant stimulus information to spatial codes; this conditional component does not depend on relative response speed. Possible connectionist implementations of the conditional mechanism are discussed.

Crisis management has become a defining feature of contemporary governance. In times of crisis, communities and members of organizations expect their leaders to minimize the impact of the crisis at hand, while critics and bureaucratic competitors try to seize the moment to blame incumbent rulers and their policies. In this extreme environment, policy makers must somehow establish a sense of normality, and foster collective learning from the crisis experience. In this uniquely comprehensive analysis, the authors examine how leaders deal with the strategic challenges they face, the political risks and opportunities they encounter, the errors they make, the pitfalls they need to avoid, and the paths away from crisis they may pursue. This book is grounded in over a decade of collaborative, cross-national case study research, and offers an invaluable multidisciplinary perspective. This is an original and important contribution from experts in public policy and international security

The local power of many popular non‐cointegration tests has recently been shown to depend on a certain nuisance parameter. Depending on the value of that parameter, different tests perform best. This paper suggests combination procedures with the aim of providing meta tests that maintain high power across the range of the nuisance parameter. 1 We demonstrate the local power of the new meta tests to be in general almost as high as that of the most powerful of the underlying tests. When the underlying tests have similar power, the meta tests even appear more powerful than the best underlying test. At the same time, our new meta tests avoid the arbitrary decision which test to use if individual test results conflict. Moreover it avoids the size distortion inherent in separately applying multiple tests for cointegration to the same dataset. We use the new tests to investigate 286 datasets from published cointegration studies. There, in one‐third of all cases individual tests give conflicting results whereas our meta tests provide an unambiguous test decision.

We present the results of Monte Carlo simulations on a system of hard ellipsoids of revolution with length-to-breadth ratios a/b = 3, 2·75, 2, 1·25 and b/a = 3, 2·75, 2, 1·25. We identify four distinct phases, viz. isotropic fluid, nematic fluid, ordered solid and plastic solid. The coexistence points of all first order phase transitions are located by performing absolute free energy computations for all coexisting phases. We find nematic phases only for a/b ⩾ 2·75 and a/b ⩽ 1>/2·75. A plastic solid is only observed for 1·25 ⩾ a/b ⩾ 0·8. It is found that the phase diagram is surprisingly symmetric under interchange of the major and minor axes of the ellipsoids.

SUMMARY. 1. Studies on the zonation of benthic fauna in fourteen streams situated in a variety of latitudes from Alaska to New Zealand have been evaluated. 2. We suggest that physical characteristics of flow (‘stream hydraulics’) are the most important environmental factor governing the zonation of stream benthos on a world‐wide scale. 3. From the source to the mouth of a stream, zones of transition in stream hydraulics' occur, to which the general pattern of stream invertebrate assemblages can be related. In these zones benthic community stability and resilience must be different from those upstream and downstream of the hydraulic transition zones.

We have obtained U, B, and R CCD surface photometry for a sample of 39 elliptical galaxies. For each galaxy we have determined the surface brightness profile, U - R and B - R color profiles, and the ellipticity and position angle profiles, all as a function of major axis radius, using a two-dimensional ellipse fitting program. In addition, we have derived the sin and cos 3 θ and 4 θ terms that describe the high-order deviations of the B and R isophotes from ellipses. While it is very common for ellipticals to display measurable 3 θ and 4 θ terms, the amplitudes of these terms rarely exceed 0.5%. The isophotes of elliptical galaxies are very well characterized by ellipses. The surface brightness and color profiles are given to radii at which the error in the profile reaches 0.1 mag from the uncertainty in the brightness of the night sky. We have carried out a series of simulations of the effects of seeing on luminosity and ellipticity profiles, to determine the radius beyond which the errors in our data from seeing are less than 0.05 mag and 0.02 in ellipticity. Measurable effects of seeing extend to surprisingly large radii, as much as 5 -10 seeing radii, depending upon the ellipticity of the galaxy and the form of the surface brightness profile. Ellipticity and position angle profiles are usually the same in all passbands with no indication that the contours of constant color are more or less flattened than the isophotes, i.e., the isochromes and isophotes have the same shapes, but the insensitivity of the ellipticity to differences between these properties makes this a weak argument. The high-order terms, particularly the 3θ terms, appear to be sensitive diagnostics for the existence of dust in ellipticals. We find that all the galaxies in this sample either become bluer in B - R and U - R with increasing radius or are of constant color. Mean values for the logarithmic gradients in color are -0.09 mag (arcsec)^-2^ per dex in radius in B - R, and - 0.20 mag (arcsec)^-2^ per dex in radius in U - R. These color changes are consistent with a decrease in the [Fe/H] of approximately 0.20 per decade in radius. Surprisingly, there is no correlation of color gradient with luminosity. It is striking, however, that the lowest luminosity galaxies in the sample (i.e., those with M_B_ > - 20) do not show any color gradients. They have boxy isophotes, and are also rotationally flattened. While these properties may be related to the fact that they are companions of larger ellipsoidal systems, it could provide an important clue to the formation of ellipticals. Low luminosity ellipticals that are not close companions to giant ellipticals need to be studied.

The hypoxia-inducible factor 1 (HIF-1) plays a critical role in cellular responses to hypoxia. The aim of the present study was to evaluate which genes are induced by hypoxia, and whether this induction is mediated by HIF-1, by expression microarray analysis of wt and HIF-1alpha null mouse fibroblasts. Forty-five genes were up-regulated by hypoxia and 40 (89%) of these were regulated by HIF-1. Of the 114 genes down-regulated by hypoxia, 19 (17%) were HIF-1-dependent. All glycolytic enzymes were strongly up-regulated by hypoxia in a HIF-1-dependent manner. Genes already known to be related to hypoxia, such as glucose transporter 1, BNIP3, and hypoxia-induced gene 1, were induced. In addition, multiple new HIF-1-regulated genes were identified, including genes involved in metabolism (adenylate kinase 4, galactokinase), apoptosis (galectin-3 and gelsolin), and invasion (RhoA). Genes down-regulated by hypoxia were involved in cytoskeleton maintenance (Rho kinase), mRNA processing (heterogeneous nuclear ribonucleoprotein H1 and splicing factor), and DNA repair (REV3). Furthermore, seven cDNAs from genes with unknown function or expressed sequence tags (ESTs) were up-regulated and 27 such cDNAs were down-regulated. In conclusion, hypoxia causes down- rather than up-regulation of gene expression and HIF-1 seems to play a major role in the regulation of hypoxia-induced genes.

PURPOSE: Half the patients with acute myeloid leukemia (AML) who achieve complete remission (CR), ultimately relapse. Residual treatment-surviving leukemia is considered responsible for the outgrowth of AML. In many retrospective studies, detection of minimal residual disease (MRD) has been shown to enable identification of these poor-outcome patients by showing its independent prognostic impact. Most studies focus on molecular markers or analyze data in retrospect. This study establishes the value of immunophenotypically assessed MRD in the context of a multicenter clinical trial in adult AML with sample collection and analysis performed in a few specialized centers. PATIENTS AND METHODS: In adults (younger than age 60 years) with AML enrolled onto the Dutch-Belgian Hemato-Oncology Cooperative Group/Swiss Group for Clinical Cancer Research Acute Myeloid Leukemia 42A study, MRD was evaluated in bone marrow samples in CR (164 after induction cycle 1, 183 after cycle 2, 124 after consolidation therapy). RESULTS: After all courses of therapy, low MRD values distinguished patients with relatively favorable outcome from those with high relapse rate and adverse relapse-free and overall survival. In the whole patient group and in the subgroup with intermediate-risk cytogenetics, MRD was an independent prognostic factor. Multivariate analysis after cycle 2, when decisions about consolidation treatment have to be made, confirmed that high MRD values (> 0.1% of WBC) were associated with a higher risk of relapse after adjustment for consolidation treatment time-dependent covariate risk score and early or later CR. CONCLUSION: In future treatment studies, risk stratification should be based not only on risk estimation assessed at diagnosis but also on MRD as a therapy-dependent prognostic factor.

Biology takes a special place among the other natural sciences because biological units, be they pieces of DNA, cells, or organisms, reproduce more or less faithfully. Like any other biological process, reproduction has a large random component. The theory of branching processes was developed especially as a mathematical counterpart to this most fundamental of biological processes. This active and rich research area allows us to determine extinction risks and predict the development of population composition, and also uncover aspects of a population's history from its current genetic composition. Branching processes play an increasingly important role in models of genetics, molecular biology, microbiology, ecology, and evolutionary theory. This book presents this body of mathematical ideas for a biological audience, but should also be enjoyable to mathematicians, if only for its rich stock of rich biological examples. It can be read by anyone with a basic command of calculus, matrix algebra, and probability theory. More advanced results from basic probability theory are treated in a special appendix.

The names of all mosses published up to the end of August 2011 in the countries of the Mediterranean basin, the Macaronesian Islands and Bulgaria are compiled in an annotated checklist. The list comprises accepted names and synonyms, and provides explanatory annotations for ambiguous and disputed names. Literature references supporting the reports in each individual area are given only for taxa reported once or in a single locality. A total of 1168 accepted species and 81 infraspecific taxa are reported from the whole area.

Temporal and spatial patterns of atmospheric carbon dioxide elucidate the global carbon cycle as it functions on time scales ranging from days to decades. In preparation for interpreting these patterns with a three-dimensional model of atmospheric tracer transport, we have summarized CO2 measurements obtained by the Scripps Institution of Oceanography since 1957 from an array of stations between the Arctic Basin and the South Pole. Ten stations contributed to the array, supplemented by sampling on ships and ice floes. After applying consistent calibrating criteria to the full set of data, we have decomposed each record into an annually periodic signal and a seasonally adjusted time series, smoothed to emphasize interannual variations. We have computed harmonic coefficients to express the average seasonal cycle. We have determined seasonally adjusted concentrations for 1962, 1968, and annually from 1978 to 1986, to reflect slowly varying characteristics of the carbon cycle, and we have assembled these data in north-to-south profiles to reveal spatial patterns. We have similarly assembled isotopic data derived from measurements of the 13C/12C isotopic ratio of atmospheric CO2, made always on the same air measured for its CO2 concentration. We have extended the data sets for stations at Mauna Loa Observatory, Hawaii and the South Pole through 1988 to create a continuous time series which approximates the global change in CO2 concentration over 32 years and the isotopic ratio over 11 years. To establish interannual changes in the carbon cycle, we have developed a compartment model which treats the transfers of carbon between global atmospheric and terrestrial biospheric carbon pools, and between these pools and a world ocean in which vertical transport occurs by diffusion. In a variant to this model the oceanic submodel was replaced with a three-dimensional oceanic transport model. Both the concentration and isotopic ratio of CO2 show clearly defined seasonal cycles and evidence that the carbon cycle responds to El Niño events that recur in the records approximately every 4 years. According to the isotopic data, oscillations in CO2 associated with El Niño events are produced by opposing oceanic and biospheric fluxes several times larger than the net fluxes inferred from the CO2 concentration data alone. On a longer time scale the concentration data show a weak, approximately 11 year, cycle possibly driven by variations in solar irradiance. On a still longer time scale the data indicate that a larger apparent fraction of CO2 from fossil fuel combustion has been retained in the air during the past 14 years than formerly, in spite of a reduced acceleration in worldwide fuel consumption which, according to the compartment model, should have led to a lesser retention in the air after 1974. The isotopic records suggest that this increased retention is partially a result of ocean warming, but is predominantly caused by an accelerated release of CO2 by the terrestrial biosphere.

The vortex-lattice phase transitions in ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8}$ crystals with various oxygen stoichiometry are studied using local magnetization measurements. Three new findings are reported: The first-order phase transition line at elevated temperatures shifts upward for more isotropic overdoped samples. At lower temperatures another sharp transition is observed that results in enhanced bulk pinning in the second magnetization peak region. The two lines merge at a multicritical point at intermediate temperatures forming apparently a continuous phase transition line that is anisotropy dependent.