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We observe a number of well defined peaks in the photoemission spectra from Y(0001) over the photon energy range 25 eV

Angle-resolved UV photoemission has been used to investigate the electronic structure of the (0001) surfaces of scandium, yttrium, praseodymium and gadolinium. Off-normal emission spectra were recorded with high angular resolution, enabling detailed mapping of the dispersion of valence band features. Yttrium and gadolinium show similar results to published data from Ho(0001), suggesting minimal 4f influence in the lanthanide bandstructures. Differences seen on praseodymium and scandium may be due to 4f derived states and surface states respectively.

Existing approaches to characterizing intrusion detection systems focus on performance under test conditions. While it is well-understood that operational conditions may differ from test conditions, little attention has been paid to the question of assessing the effect on IDS results of parameter estimation errors resulting from these differences. In this paper we consider this question in the context of multi-step attacks. We derive simulated distributions of the posterior probability of exploit given the observation of a series of alerts and bounds on the posterior uncertainty given a particular distribution of the model parameters. Knowledge of such bounds introduces the novel prospect of a confidence versus agility tradeoff in IDS administration. Such a tradeoff could give administrators flexibility in IDS configuration, allowing them to choose detection confidence at the price of detection latency, according to organizational priorities.

This paper examines the information security implications of the Sarbanes-Oxley (SOX) Act of 2002. It is well-established in the information systems field that managers do not rank security as a high priority, an attitude that is believed to result in low levels of information system protection. We consider whether information security benefits are likely to result from compliance efforts associated with SOX. A qualitative analysis consisting of semi-structured interviews, participant observation, and document analysis was conducted to address this question. Based on the results of this investigation, a framework was developed which integrates several factors associated with SOX compliance and demonstrates that firms are likely to reap information security benefits as a result of SOX compliance efforts.

Solar radiation is not commonly recorded in the meteorological network and it is therefore generally necessary to predict its value theoretically. The majority of solar radiation predictive methods assume a standard atmosphere. Thus they are of limited application to ‘all-year’ thermal design models. A review of the nature of direct solar radiation and methods by which it can be predicted are presented.

The relationships currently used to describe the convective heat exchanges at the external surfaces of buildings are based on wind tunnel measurements undertaken over 40 years ago. Recent field measurements have disclosed inadequacies in the application of this early work. This paper provides a review of the nature of convective heat exchanges and discusses the various relationships which have been presented in the literature to describe it.

Although the impact of solar radiation on the thermal performance of buildings is well documented, the longwave radiative environment is generally little understood. Several relationships have been proposed in the literature which describe the incoming atmospheric radiation component for both clear and cloudy sky conditions but their inclusion in thermal design models is still relatively unexplored. This review discusses the nature of the longwave radiative environment and explains the origins and characteristics of equations which quantify it.

The micronucleus test is an efficient and cost-effective alternative to metaphase analysis for rapid screening of potential clastogenic chemicals (Kliesch et al., 1981). The transplacental micronucleus test (Cole et al., 1979, 1981) is sensitive to agents which are negative in bone-marrow tests because production of erythroid cells in the fetal liver persists during late gestation, when the fetal hepatic cells have developed qualitatively and quantitatively greater capacity for metabolic activation than adult bone marrow (Cole et al., 1981, 1982). Cell-kinetic analyses of prenatal erythropoiesis (Paul et al., 1969; Tarbutt and Cole, 1970) provide a theoretical rationale for exposure protocols in the transplacental test. If the effective life of a clastogenic agent is much shorter than the fetal erythroblast cell cycle time (about 6.5 h) micronuclei will be randomly distributed within each cohort of descendent PCEs (since G 1 and S phases occupy about 70% of the erythroblast cell cycle), and will be maximally represented in the fetal liver, about 15 h after exposure. As the effective life of the agent approaches the erythroblast cell cycle time then the highest frequency of MN will be within the younger PCEs, since their ancestral erythroblasts will have been 'at risk' longest, but the peak will still be expressed after about 15 h. However, if the effective life of the test chemical extends for more than one cell cycle time (e.g. some nitrosamines and polycyclic aromatic hydrocarbons), then peak MNPCE frequences will be reached correspondingly later and measurements at peak value are the result of treatments extending over more than one cell cycle. This report analyses the sensitivity of the test when DNA-damage is

This paper gives the derivation of relationships which predict the direct solar radiation incident upon buildings which explicitly allow for variation in atmospheric water and dust.

Isolated nuclei from chick skeletal muscle cell cultures at different stages of differentiation were labelled in vitro with γ-[ 32 P]ATP. Nuclear proteins were separated into saline-soluble and non-histone (NHP) fractions and analysed by two-dimensional gel electrophoresis and autoradiography. Relatively few proteins (10–12) were phosphorylated to any extent and most of these corresponded to minor, or even undetectable, components on stained gels. 32 P incorporation into most of these proteins increased between 24 and 40 h and decreased sharply between 40 and 66 h, the changes being more marked in some phosphoproteins than in others. Pulse-chase data suggest that these overall changes in phosphorylation reflect changes in protein kinase, rather than protein phosphatase activities. One highly phosphorylated acidic protein (mol. wt 10 000 D; pI 4.2) which was undetectable on stained gels, showed a continuous increase in 32 P incorporation between 24 and 66 h in both saline-soluble and NHP fractions. This protein may be the muscle counterpart of a phosphorylated nuclear protein partially characterized in other cell types. Both nuclear protein phosphorylation and low molecular weight non-histone proteins have been particularly implicated in activation of gene transcription in other systems, although we have no direct evidence, as yet, to connect them with control of myoblast growth and differentiation.

The effectiveness of 3 compounds, procarbazine, mitomycin C and cyclophosphamide as inducers of sister-chromatid exchanges (SCEs) in granulocyte-macrophage progenitor cells, in foetal liver and bone marrow from pregnant mice at day 17 of gestation were determined. Cyclophosphamide and procarbazine induced similar SCE frquencies in maternal and foetal cells. Mitomycin C was slightly less effective in foetal liver than in maternal bone marrow. In contrast to the results of SCE induction, cyclophosphamide produced more micronucleated polychromatic erythrocytes in foetal liver than in bone marrow. The SCE results for mitomycin C and procarbazine are compared with results obtained previously for micronuclei induction in 15-day pregnant animals.

The induction of sister-chromatid exchanges (SCEs) by cyclophosphamide (CP) and procarbazine (PC) in mouse granulocyte-macrophage precursor cells (GM cells) and erythroblasts from foetal liver, and cells from foetal brain and foetal lung has been measured. Agents were administered in vivo, and cells explanted into BrdUrd-containing medium for 2 cell cycles in vitro (using specific growth-promoting substances where necessary) to determine SCE frequency. Tissue and cell-type differences in responses were observed, and it is concluded that the in vivo/in vitro transplacental SCE technique is a useful indicator of genotoxic effects of agents which are potential transplacental carcinogens.

A cell-kinetic model for the application of the micronucleus test to polychromatic erythrocytes in mouse fetal liver, fetal blood, and maternal bone marrow after exposure to clastogenic agents is described. The time of expression and dose-response relationships obtained with γ-radiation, methyl methanesulphonate, procarbazine, mitomycin C and benzo[a]pyrene are analysed in terms of this model. The numbers of target cells damaged per unit dose has been calculated and the dose equivalents obtained. Maternal and fetal cells show similar sensitivity to γ-radiation, but fetal cells are markedly more sensitive to MMS and procarbazine. This probably due to differences in tissue distribution and metabolism. Maternal and fetal erythroid tissues can show linear and exponential dose-response relationships, which may not coincide (e.g. with MMS). It is concluded that risks from fetal exposure to genotoxic agents cannot be reliably predicted from in vivo tests restricted to adult animals. However, the micronucleus technique appled to fetal erythroid cells proveds a rapid and reliable short-term test, appropriate to minimising risks of genome damage during prenatal development.

The induction of micronuclei in human cord blood lymphocytes by treatment with γ-irradiation and bleomycin has been measured. Culture durations which gave peak MN frequencies were determined. The lowest tested doses, 0.1 Gy irradiation and 1.25 μg/ml bleomycin, produced significant increases in the frequency of micronuclei. The spontaneous frequency of micronucleated lymphocytes in 28 cord blood samples ranged between 0.5 and 9.5 per thousand lymphocytes, with a modal value of 2.5. The method is evaluated for its potential usefulness in monitoring populations for chromosome breakage.

The effectiveness of 6 chemicals (benzo[a]pyrene, (BaP), cyclophosphamide (CP), diethylnitrosamine (DEN), methyl methanesulphonate (MMS), mitomycin C (MC) and procarbazine (PC) ) as inducers of micronuclei in foetal liver and maternal bone marrow erythroblasts has been determined, and related to that of gamma-radiation. CP, DEN, MMS and PC were all more effective in the foetal liver. The induction of micronuclei and SCEs by each chemical in foetal erythroblasts after in vivo exposure was measured. When expressed as induction of sister-chromatid exchanges (SCEs) per erythroblast/induction of micronuclei per erythroblast (/microM/kg), the ratios obtained were MC 580, BaP 470, DEN 430, CP 258, MMS 140 and PC 13. The lowest doses detected as potentially genotoxic by each test in foetal liver erythroblasts are (with the exception of PC which is a relatively ineffective inducer of SCEs) similar. When isolated foetal livers were exposed in vitro, SCE dose responses to BaP, MC, MMS and PC could be directly related to those from in vivo exposure, indicating the role of the foetal liver in metabolic activation, but CP was considerably more cytotoxic. The transplacental micronucleus test, and in vivo/in vitro method for SCEs in foetal liver erythroblasts, provide sensitive, complementary assays for genotoxic effects of chemicals during prenatal life. Since foetal liver possesses greater metabolic potential than adult bone marrow, the transplacental tests respond to genotoxic agents not detected by bone-marrow systems.

Many problems that arise in transport theory for the motion of charged particles involve the calculation of integrals of exponential type. Three independent parameters appear in the integral considered. Two analytic series equivalent to the integral are presented, one of which, involving Bessel functions, is related to a Kapteyn series. Numerical calculations have been performed over a wide range of parameter values and compared with various quadrature routines. The analytic series proved generally more accurate and efficient.

Certain characters of the large uninucleate amoebae, A. proteus and A. discoides are influenced by self-replicating cytoplasmic hereditary determinants. An attempt to investigate the cellular basis of this cytoplasmic inheritance has been made, by injecting a comparatively small quantity of cytoplasm from one species into the other. Two cytoplasmically-inherited characters were selected as markers in these experiments, mean nuclear diameter and streptomycin sensitivity; A. proteus differs from A. discoides in having a higher mean nuclear diameter and greater streptomycin sensitivity. It was found that injection of A. discoides cytoplasm into whole A. proteus resulted in a proportion of the clones formed from amoebae which survived the operation, in significant decreases in nuclear diameter and in streptomycin sensitivity. These changes were not, however, invariably linked. In addition, the viability of A. discoides nuclei in these clones was increased. It therefore appears that a situation in which cytoplasmic hereditary determinants can be expressed, and presumably replicate, results from the injection and assimilation of a relatively small volume of cytoplasm.

1. 1. Adult females of Ascarias lumbricoides contained 11·9 per cent and adult males 6·7 per cent total lipid on dry weight basis. 2. 2. Females contained 0·21 per cent total sterol, whereas males contained 0·38 per cent sterol. Sterol ester averaged 40 per cent of the total sterol in females and 60 per cent in males. 3. 3. Nematode sterols where cholesterol, cholestanol, campesterol, campestanol, β-sitosterol and stigmastanol. Cholesterol accounted for 39–40 per cent and “phytosterols” for another 40 per cent of the total sterol in both males and females.

The growth rates of clones of various strains of Amoeba proteus, in growth limiting concentrations of streptomycin, have been measured. These experiments have shown the existence of naturally occurring inter-strain differences in resistance to this drug. The growth of sensitive strains is retarded in concentrations higher than 0.06 μg/ml. “Moderately resistant” and “resistant” strains can be differentiated, four times and six times, respectively, as resistant as the most sensitive strain. All strains of A. proteus investigated absorb the same amount of streptomycin per individual amoeba in standard conditions. The level of resistance of clones originating from heterotransfers between sensitive and resistant A. proteus strains, produced by the de Fonbrune technique of nuclear transplantation, is the same as the sensitive parent. Therefore the mechanisms conferring higher levels of resistance on some strains of A. proteus cannot be transmitted by either nuclear factors or cytoplasmic factors independently. A single strain of A. discoides was also investigated and found to be six times as resistant as the most sensitive A. proteus and to absorb only half as much streptomycin in similar conditions. Both heterotransfer strain types [resistant nucleus (A. discoides) in sensitive cytoplasm (A. proteus) and sensitive nucleus (A. proteus) in resistant cytoplasm (A. discoides)] are more resistant and absorb less streptomycin than the sensitive parent. No additive effects between factors from resistant A. proteus and A. discoides occurred in the relevant heterotransfer strains. It is concluded that independent nuclear and cytoplasmic factors determine the higher resistance of A. discoides, which is probably based on lower permeability to streptomycin, and that the cytoplasmic system is self-replicating.

Synthesis and metabolism of RNA in dividing mouse myoblasts, and post-mitotic myoblasts and multinucleate myotubes in vitro has been investigated by chromatography on methylated albumin Kieselguhr columns. Total RNA synthesis per nucleus in the post-mitotic population is approx. 1 3 that in dividing myoblasts. Synthesis of ribosomal RNA and ‘DNA-like’ RNA is differentially affected. Synthesis of ‘DNA-like’ RNA in myotubes is approx. half that in dividing myoblasts, but ribosomal RNA synthesis is reduced to 1 5 . In the post-mitotic stages of myogenesis, ‘DNA-like’ RNA shows enhanced breakdown of large species (Q2) to smaller tenaciously bound molecules (TD-RNA).

Sterols in the plant-parasitic nematodes Diylenchus triformis and D. dipsaci were analyzed qualitatively and quantitatively. Qualitative analyses were made utilizing gas-liquid chromatography (GLC), thin-layer chromatography (TLC), melting-point determinations, infrared spectra, and quantitative analyses were made by GLC. Major sterols in both D. triformis and D. dipsaci were cholesterol (Δ 5 -cholestene-3β-ol) and lathosterol (Δ 7 -cholestene-3β-ol). Lathosterol was the major sterol in D. triformis (60%) whereas D. dipsaci contained approximately equimolar concentrations of cholesterol and lathosterol. D. dipsaci sometimes contained C 29 phytosterols, almost entirely in ester form, which were also found in the host (alfalfa callus tissue). These phytosterols were tentatively identified as α-spinasterol and Δ 7 -stigmastene-3β-ol, the major sterol being α-spinasterol. The major sterol of Pyrenochaeta terrestris , the fungal host of D. triformis in culture, was ergosterol. Total sterol in D. triformis averaged 0.09% and in D. dipsaci 0.06% on a dry weight basis. Sterol esters averaged 48% of the total sterol in D. triformis and 58% in D. dipsaci .

Ribosomal RNA, labelled with uridine and methionine, from dividing and post-mitotic mouse prenatal muscle cell cultures, has been characterised on polyacrylamide gels. Progress of differentiation in cultures was monitored by recording changing proportions of nuclei in myotubes, and increases in creatine kinase activity. Ribosomal RNA synthesis in myotubes is reduced relative to that in dividing cell cultures and considerable wastage of processed ribosomal RNA occurs. This changed pattern of ribosomal RNA production appears to be established in the post-mitotic myoblasts prior to fusion.

Microsporidian spores can be purified by using a method based on the principles of “triangulation” and countercurrent distribution chromatography. Levels of purity of at least 99% were achieved by using this method to purify spores of Nosema heliothidus from infected larval Heliothis zea and spores of Nosema apis from infected adult Apis mellifera.

A simple method is presented which determines the numerical stability or instability in the computation of any solution of a three-term homogeneous linear difference equation of order m in terms of the size of a single parameter. The method is illustrated by application to a second order and to a third order difference equation. Excellent agreement with predictions is reported.

The purpose of this research was to analyze past and present federal incentives to production of various energy sources and thereby assist the Division of Conservation and Solar Applications, Department of Energy, in the study and recommendation of federal incentives for the development of solar energy. The research was divided into five parts: a survey of current thought about incentives for solar energy production; the theoretical approach to analyzing and characterizing incentives; a generic view of the energy incentive creating landscape for 1978; analysis of the major energy sources (nuclear, hydro, coal, electricity, oil, and gas) along their trajectories from exploration to waste management, including their costs in 1978 dollars; and insights into potential incentives for solar policy. Economic, political, organizational, and legal viewpoints were considered in formulating the typology of incentives. Eight types of incentives were identified.