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 firstname.lastname@example.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.
The International Centre for Diffraction Data (1CDD), formally the Joint Committee for Powder Diffraction Standards (JCPDS), recently published a compilation of metal and alloy indexes of powder diffraction and structural data. This compilation is designed to make the identification and characterization of metallic and related materials easier and far more accurate. Systematic searches for chemical analogs and greater use of partial chemical knowledge are now possible.
In this article, we demonstrate that the combination of elemental and phase mapping is a very powerful tool for characterizing sputtered, binary plutonium alloys.
A specially designed energy-dispersive spectrometer equipped with an automated x-y translational stage was used to measure elemental differences in several disks sputter-coated with binary plutonium alloys. Automated diffractometer scans were obtained from selected areas on the disks by using specially designed sample holders. The elemental differences were then correlated with the phases present and the observed corrosion resistance. The elemental spectra and diffractometer scans were analyzed using a modified version of the SPECPLOT program. This program enables the user to analyze both energy-dispersive elemental data and diffractometer data using a single program.
This study evaluated in a rigorous 18-month randomized controlled trial the efficacy of an enhanced vocational intervention for helping individuals with a recent first schizophrenia episode to return to and remain in competitive work or regular schooling.
Individual Placement and Support (IPS) was adapted to meet the goals of individuals whose goals might involve either employment or schooling. IPS was combined with a Workplace Fundamentals Module (WFM) for an enhanced, outpatient, vocational intervention. Random assignment to the enhanced integrated rehabilitation program (N = 46) was contrasted with equally intensive clinical treatment at UCLA, including social skills training groups, and conventional vocational rehabilitation by state agencies (N = 23). All patients were provided case management and psychiatric services by the same clinical team and received oral atypical antipsychotic medication.
The IPS–WFM combination led to 83% of patients participating in competitive employment or school in the first 6 months of intensive treatment, compared with 41% in the comparison group (p < 0.005). During the subsequent year, IPS–WFM continued to yield higher rates of schooling/employment (92% v. 60%, p < 0.03). Cumulative number of weeks of schooling and/or employment was also substantially greater with the IPS–WFM intervention (45 v. 26 weeks, p < 0.004).
The results clearly support the efficacy of an enhanced intervention focused on recovery of participation in normative work and school settings in the initial phase of schizophrenia, suggesting potential for prevention of disability.
In large, impersonal moral orders many of us wish to maintain good will toward our fellow citizens only if we are reasonably sure they will maintain good will toward us. The mutual maintaining of good will, then, requires that we somehow communicate our intentions to one another. But how do we actually do this? The current paper argues that when we engage in moral responsibility practices—that is, when we express our reactive attitudes by blaming, praising, and resenting—we communicate a desire to maintain good will to those in the community we are imbedded in. Participating in such practices alone will not get the job done, though, for expressions of our reactive attitudes are often what economists call cheap talk. But when we praise and blame in cases of moral diversity, expressions of our reactive attitudes act as costly signals capable of solving our social dilemma.
The object of this paper is to establish a simple connection between Thorn's theory of cobounding manifolds and the theory of modifications. The former theory is given in detail in (8) and sketched in (3), while the latter is worked out in (1). In particular in (1) it is shown that the only modifications which can transform one differentiable manifold into another are what I call below spherical modifications, which consist in taking out a sphere from the given manifold and replacing it by another. The main result is that manifolds cobound if and only if each is obtainable from the other by a finite sequence of spherical modifications.
The technique consists in approximating the manifolds by pieces of algebraic varieties. Thus if M1 and M2 form the boundary of M, the last is taken to be part of an algebraic variety such that M1 and M2 are two members of a pencil of hyperplane sections.
Let k be an algebraically closed field and let x1, x2, . . . , xn be indeterminates. Denote by Rn the ring k[[x1, x2, … , xn]] of power series in the xi With coefficients in the field k. Let and be two ideals in this ring. Then and will be said to be analytically equivalent if there is an automorphism T of Rn such that T() = . and will be called analytically equivalent under T.
The above situation can be described geometrically as follows. The ideals and can be regarded as defining algebroid varieties V and V' in (x1, x2, … , xn)-space, and these varieties will be said to be analytically equivalent under T.
The automorphism T can be expressed by means of equations of the form :
where the determinant is not zero and the fi are power series of order not less than two (that is to say, containing terms of degree two or more only).
In a previous paper (4) the author worked out some results on the analytic connectivity properties of real algebraic varieties, that is to say, properties associated with the joining of points of the variety by analytic arcs lying on the variety. It is natural to ask whether these properties can be carried over to analytic varieties, since the proofs in the algebraic case depend mainly on local properties. But although this generalization can be carried out to a large extent, there are, nevertheless, difficulties in the analytic case, owing mainly to the fact (cf. 2, § 11) that a real analytic variety may not be definable by means of a set of global equations. Thus, although the general idea of the treatment given here is the same as in (4), some variation in the details of the method has proved to be necessary, and some of the final results are slightly weaker in form.
In his paper on the algebraic approximation of differentiable manifolds Nash (1) introduced the concept of a sheet of a real algebraic variety (see the definition in §16 below) and raised certain questions of a general nature. In attempting to answer these questions it has been necessary to evolve some sort of technique for manipulating curves on algebraic varieties, and, in particular, to set up a criterion for the possibility of approximating a sequence of analytic arcs (definition in §1) joined end to end by a single analytic arc.
Methane formation in the rumen represents a substantial loss of energy to the animal and is also a major source of greenhouse gas emissions from agriculture. Methanogenesis is the main means of disposal of hydrogen during rumen fermentation. The formation of propionate represents an alternative route of hydrogen disposal, providing sufficient propionate precursors are available. Theoretically, adding propionate precursors should stimulate propionate production and decrease methane production. In the present experiment, the effects of two potential precursors of propionate, fumarate and acrylate, on rumen fermentation and methane production were investigated in a rumen simulating fermentor.
To evaluate healthcare worker (HCW) risk of self-contamination when donning and doffing personal protective equipment (PPE) using fluorescence and MS2 bacteriophage.
Prospective pilot study.
A total of 36 HCWs were included in this study: 18 donned/doffed contact precaution (CP) PPE and 18 donned/doffed Ebola virus disease (EVD) PPE.
HCWs donned PPE according to standard protocols. Fluorescent liquid and MS2 bacteriophage were applied to HCWs. HCWs then doffed their PPE. After doffing, HCWs were scanned for fluorescence and swabbed for MS2. MS2 detection was performed using reverse transcriptase PCR. The donning and doffing processes were videotaped, and protocol deviations were recorded.
Overall, 27% of EVD PPE HCWs and 50% of CP PPE HCWs made ≥1 protocol deviation while donning, and 100% of EVD PPE HCWs and 67% of CP PPE HCWs made ≥1 protocol deviation while doffing (P=.02). The median number of doffing protocol deviations among EVD PPE HCWs was 4, versus 1 among CP PPE HCWs. Also, 15 EVD PPE protocol deviations were committed by doffing assistants and/or trained observers. Fluorescence was detected on 8 EVD PPE HCWs (44%) and 5 CP PPE HCWs (28%), most commonly on hands. MS2 was recovered from 2 EVD PPE HCWs (11%) and 3 CP PPE HCWs (17%).
Protocol deviations were common during both EVD and CP PPE doffing, and some deviations during EVD PPE doffing were committed by the HCW doffing assistant and/or the trained observer. Self-contamination was common. PPE donning/doffing are complex and deserve additional study.
Continuous injection models for the secular behavior of the radio and X-ray emission from supernova remnants are examined and compared with the observations. Among other things, it is concluded that (1) continuous injection probably occurs for at least 10 yr in every case and about 1000 yr in most supernova remnants, in which case the supernova remnants 3C392, W28, Pup A and IC443 should produce 1–10 keV X-ray fluxes ≈ 10-10 ergs/cm2-sec, and (2) the X-ray sources in the Crab Nebula, Cas A and Tycho can be explained in terms of a model wherein continuous injection occurs for 300 yr for the Crab Nebula, much less than 250 yr for Cas A and much longer than 400 yr for Tycho. Finally, it is shown that if Tycho and Cas A contain an X-ray star such as NP 0532, it is quite possible that the X-ray emission from those sources is predominantly due to the X-ray star.
We have attempted to explain the observed excitation conditions in the filamentary system of the Crab Nebula in terms of ionization and heating by high frequency radiation. It was found that it is possible to reasonably fit most of the observed lines by assuming either (1) an ultraviolet continuum which smoothly joins the optical and X-ray data and a gas composition in which the number densities of hydrogen and helium are equal, (2) a spectrum which drops off about as steeply as v-2 and therefore does not smoothly fit the X-ray spectrum, or (3) an ultraviolet continuum which smoothly joins the optical and X-ray data plus strong emission-line features near 20 eV. A UV continuum which is much larger than in these models results in too much ionization in the filaments. The calculations suggest that most of the filaments consist of outer ionized regions with cores of neutral gas, so that the mass of the filamentary shell may be considerably larger than the 1.45 M⊙ required to explain the emission line intensities.
40Ar/39Ar ages of most single ice-ratted amphiboles from Heinrich layer 2 (H2) from a core in the Labrador Sea, a core in the eastern North Atlantic and a core in the western North Atlantic range from 1600 to 2000 Ma. This range is identical to that for K/Ar ages from the Churchill province of the Canadian Shield that outcrops at Hudson Strait and forms the basement of the northern part of Hudson Bay. The ambient glacial sediment includes some younger and older grains derived from Paleozoic, Mesoproterozoic and Archean sources, but still the majority of the amphiboles have ages in the 1600–2000 Ma interval. The Ca/K ratios of these 1600–2000 Ma old amphiboles, however, have a bimodal distribution in contrast with the uniformity of the Ca/K ratios of H2 amphiboles. This indicates that 1600–2000 Ma old amphiboles of the ambient sediment were derived from an additional Early Proterozoic source besides Churchill province. In H2, Churchill-derived grains constitute 20–40% of the ice-rafted debris (IRD). The fraction in the ambient glacial sediment is 65–80%. Results presented here are consistent with the hypothesis that Heinrich events were produced by a sudden intensification of the iceberg discharge through Hudson Strait that mixed, in the North Atlantic, with icebergs that continued to calve from other ice sheets. The shift from mixed sources in the background sediment to a large dominance of Churchill province grains in H2 indicates that, even if calving of other ice sheets intensified during the Heinrich episode, the increase in the iceberg discharge via Hudson Strait from the Hudson Bay drainage basin of the Laurentide ice sheet was by far the largest.
14C measured in trace gases in clean air helps to determine the sources of such gases, their long-range transport in the atmosphere, and their exchange with other carbon cycle reservoirs. In order to separate sources, transport and exchange, it is necessary to interpret measurements using models of these processes. We present atmospheric 14CO2 measurements made in New Zealand since 1954 and at various Pacific Ocean sites for shorter periods. We analyze these for latitudinal and seasonal variation, the latter being consistent with a seasonally varying exchange rate between the stratosphere and troposphere. The observed seasonal cycle does not agree with that predicted by a zonally averaged global circulation model. We discuss recent accelerator mass spectrometry measurements of atmospheric 14CH4 and the problems involved in determining the fossil fuel methane source. Current data imply a fossil carbon contribution of ca 25%, and the major sources of uncertainty in this number are the uncertainty in the nuclear power source of 14CH4, and in the measured value for δ14C in atmospheric methane.
Having worked on several approaches to CO2 capture over the past decade, we have studied a great number of physical and chemical solvents as well as polymer and composite membranes. Initially, most of these materials were based upon ionic liquids (ILs), however due to challenges encountered in applying ILs to meet the demanding requirements in CO2 separation processes, there is a need to reconsider what role (if any) ILs might play in CO2 capture technologies. Ultimately, more promising and robust materials will not come from ILs themselves, but from retrosynthetic analysis and a reconsideration of which structural variables and properties are (and are not) important. The hybridization of the constituent parts into entirely new, yet seemingly familiar substances, can yield greatly improved properties and economics. This manuscript highlights recent work from our group based on lessons learned from ILs that have spurred the development of new amine solvents and polymer materials to better address the demanding process conditions and requirements of CO2 capture and related separations.