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This article presents measurements of electrical and physical properties for a variety of FR4 fiberglass-reinforced resin laminates, and the respective changes following exposure to a $1.9 \times 10^{16}$ n/cm2 total neutron fluence. The selection of a printed circuit board (PCB) substrate is shown to be of consideration beyond the typical frequency-dependent parameters, specifically for high fluence radiation environments where small changes to the dielectric constant are of concern.

A group $G$ is integrable if it is isomorphic to the derived subgroup of a group $H$; that is, if $H'\simeq G$, and in this case $H$ is an integral of $G$. If $G$ is a subgroup of $U$, we say that $G$ is integrable within $U$ if $G=H'$ for some $H\leq U$. In this work we focus on two problems posed in [1]. We classify the almost-simple finite groups $G$ that are integrable, which we show to be equivalent to those integrable within $\mathrm{Aut}(S)$, where $S$ is the socle of $G$. We then classify all $2$-homogeneous subgroups of the finite symmetric group $S_n$ that are integrable within $S_n$., Comment: 12 pages, no figures

Enterotoxigenic Escherichia coli (ETEC) are a significant cause of childhood diarrhea in low-resource settings. ETEC are defined by the production of heat-stable enterotoxin (ST) and/or heat-labile enterotoxin (LT), which alter intracellular cyclic nucleotide signaling and cause the secretion of water and electrolytes into the intestinal lumen. ETEC take cues from chemicals (e.g., glycans, bile salts, and solutes) that may be liberated following enterotoxin activity to recognize entrance into the host. ETEC then alter the expression of surface adhesins called colonization factors (CFs) to attach to the intestinal epithelium, proliferate, and cause disease. Here, we used an in vivo model of oral ST intoxication to determine its impact on luminal ion concentrations via ICP-MS. We also used functional assays, including Western blots, qPCR, and toxin activity assays, to assess the impact of luminal ion flux on CF and toxin expression. Finally, we assessed ETEC strains with CFs CFA/I or CS6 in a streptomycin mouse model of ETEC colonization. ST causes rapid and significant increases in luminal chloride but significant decreases in luminal magnesium and iron. We confirmed that increased sodium chloride suppresses CFA/I production in ETEC H10407 but does not affect CS6 production in ETEC 214-4. CFA/I production in ETEC H10407 is increased when magnesium becomes limiting, although it does not affect CS6 production in ETEC 214-4. Iron restriction via deferoxamine induces CFA/I expression in ETEC H10407 but not CS6 expression in ETEC 214-4. We demonstrate that ST production is suppressed via iron restriction in H10407, 214-4, and over 50 other ETEC clinical isolates. Lastly, we demonstrate that the iron restriction of mice using oral deferoxamine pre-treatment extends the duration of ETEC H10407 (CFA/I+) fecal shedding while accelerating ETEC 214-4 (CS6+) fecal shedding. Combined, these data suggest that enterotoxins modulate luminal ion flux to influence ETEC virulence including toxin and CF production.

In their article, “On the derived subgroup of the free nilpotent groups of finite rank” R. D. Blyth, P. Moravec, and R. F. Morse describe the structure of the derived subgroup of a free nil...

The intestinal mucosa contributes to frontline gut defenses by forming a barrier (physical and biochemical) and preventing the entry of pathogenic microbes. One innate role of the human colonic epithelium is to secrete cathelicidin, a peptide with broad antimicrobial and immunomodulatory functions. In this study, the effect of cathelicidin in the maintenance of epithelial integrity, Toll-like receptor recognition, bacterial invasion and initiation of inflammatory response against Salmonella typhimurium is investigated in cultured human colonic epithelium. We found exogenous human cathelicidin restores the epithelial integrity in S. typhimurium-infected colonic epithelial (T84) cells by mostly post-translational effects associated with reorganization of zonula occludens (ZO)-1 tight junction proteins. Endogenous cathelicidin prevents S. typhimurium internalization as shown in colonic epithelial cells genetically deficient in the only human cathelicidin, LL-37 (shLL-37). Moreover, supplementation of shLL-37 cells with synthetic LL-37 reduces the grade of S. typhimurium internalization in a dose-dependent manner. Mechanistically, shLL-37 cells have lower gene expression of TLR4 and pro-inflammatory cytokine IL-1β in response to S. typhimurium. Thus, human cathelicidin aids in the early colonic epithelial defenses against enteric S. typhimurium by preventing bacterial invasion and maintaining epithelial barrier integrity, likely to occur due to the production of sensing TLR4 and pro-inflammatory cytokines.

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.

Barramundi (Lates calcarifer) are a highly valued aquaculture species, and, as obligate carnivores, they have a demonstrated preference for dietary protein over lipid or starch to fuel energetic growth demands. In order to investigate how carnivorous fish regulate nutritional cues, we examined the metabolic effects of feeding two isoenergetic diets that contained different proportions of digestible protein or starch energy. Fish fed a high proportion of dietary starch energy had a higher proportion of liver SFA, but showed no change in plasma glucose levels, and few changes in the expression of genes regulating key hepatic metabolic pathways. Decreased activation of the mammalian target of rapamycin growth signalling cascade was consistent with decreased growth performance values. The fractional synthetic rate (lipogenesis), measured by TAG 2H-enrichment using 2H NMR, was significantly higher in barramundi fed with the starch diet compared with the protein diet (0·6 (se 0·1) v. 0·4 (se 0·1) % per d, respectively). Hepatic TAG-bound glycerol synthetic rates were much higher than other closely related fish such as sea bass, but were not significantly different (starch, 2·8 (se 0·3) v. protein, 3·4 (se 0·3) % per d), highlighting the role of glycerol as a metabolic intermediary and high TAG-FA cycling in barramundi. Overall, dietary starch significantly increased hepatic TAG through increased lipogenesis. Compared with other fish, barramundi possess a unique mechanism to metabolise dietary carbohydrates and this knowledge may define ways to improve performance of advanced formulated feeds.

The NPDGamma experiment measures the parity-violating asymmetry in $\gamma$-ray emission in the capture of polarized neutrons on liquid parahydrogen. The sensitivity to the asymmetry for each detector in the array is used as a parameter in the extraction of the physics asymmetry from the measured data. The detector array is approximately cylindrically symmetric around the target and a step-wise sinusoidal function has been used for the sensitivity in the previous iteration of the NPDGamma experiment, but deviations from cylindrical symmetry necessitate the use of a Monte Carlo model to determine corrections to the geometrical factors. For the calculations, source code modifications to MCNPX were done in order to calculate the sensitivity of each cesium iodide detector to the physics asymmetry. We describe the MCNPX model and results from calculations and how the results are validated through measurement of the parity violating asymmetry of $\gamma$-rays from neutron capture on chlorine., Comment: 10 pages, 10 figures

We report the first observation of the parity-violating gamma-ray asymmetry A_{γ}^{np} in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. A_{γ}^{np} isolates the ΔI=1, ^{3}S_{1}→^{3}P_{1} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless effective field theory. We measured A_{γ}^{np}=[-3.0±1.4(stat)±0.2(syst)]×10^{-8}, which implies a DDH weak πNN coupling of h_{π}^{1}=[2.6±1.2(stat)±0.2(syst)]×10^{-7} and a pionless EFT constant of C^{^{3}S_{1}→^{3}P_{1}}/C_{0}=[-7.4±3.5(stat)±0.5(syst)]×10^{-11} MeV^{-1}. We describe the experiment, data analysis, systematic uncertainties, and implications of the result.

We report the first observation of the parity-violating gamma-ray asymmetry A_{γ}^{np} in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. A_{γ}^{np} isolates the ΔI=1, ^{3}S_{1}→^{3}P_{1} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless effective field theory. We measured A_{γ}^{np}=[-3.0±1.4(stat)±0.2(syst)]×10^{-8}, which implies a DDH weak πNN coupling of h_{π}^{1}=[2.6±1.2(stat)±0.2(syst)]×10^{-7} and a pionless EFT constant of C^{^{3}S_{1}→^{3}P_{1}}/C_{0}=[-7.4±3.5(stat)±0.5(syst)]×10^{-11} MeV^{-1}. We describe the experiment, data analysis, systematic uncertainties, and implications of the result.

Interferon-inducible transmembrane proteins (IFITMs) can restrict the entry of a wide range of viruses. IFITM3 localizes to endosomes and can potently restrict the replication of influenza A viruses (IAV) and several other viruses that also enter host cells through the endocytic pathway. Here, we investigate whether IFITMs are involved in protection in ducks, the natural host of influenza virus. We identify and sequence duck IFITM1 , IFITM2 , IFITM3 , and IFITM5 . Using quantitative PCR (qPCR), we demonstrate the upregulation of these genes in lung tissue in response to highly pathogenic IAV infection by 400-fold, 30-fold, 30-fold, and 5-fold, respectively. We express each IFITM in chicken DF-1 cells and show duck IFITM1 localizes to the cell surface, while IFITM3 localizes to LAMP1-containing compartments. DF-1 cells stably expressing duck IFITM3 (but not IFITM1 or IFITM2) show increased restriction of replication of H1N1, H6N2, and H11N9 IAV strains but not vesicular stomatitis virus. Although duck and human IFITM3 share only 38% identity, critical residues for viral restriction are conserved. We generate chimeric and mutant IFITM3 proteins and show duck IFITM3 does not require its N-terminal domain for endosomal localization or antiviral function; however, this N-terminal end confers endosomal localization and antiviral function on IFITM1. In contrast to mammalian IFITM3, the conserved YXXθ endocytosis signal sequence in the N-terminal domain of duck IFITM3 is not essential for correct endosomal localization. Despite significant structural and amino acid divergence, presumably due to host-virus coevolution, duck IFITM3 is functional against IAV. IMPORTANCE Immune IFITM genes are poorly conserved across species, suggesting that selective pressure from host-specific viruses has driven this divergence. We wondered whether coevolution between viruses and their natural host would result in the evasion of IFITM restriction. Ducks are the natural host of avian influenza A viruses and display few or no disease symptoms upon infection with most strains, including highly pathogenic avian influenza. We have characterized the duck IFITM locus and identified IFITM3 as an important restrictor of several influenza A viruses, including avian strains. With only 38% amino acid identity to human IFITM3, duck IFITM3 possesses antiviral function against influenza virus. Thus, despite long coevolution of virus and host effectors in the natural host, influenza virus evasion of IFITM3 restriction in ducks is not apparent.

The author has taught an inquiry-based liberal arts mathematics class using the text “The Heart of Mathematics: An Invitation to Effective Thinking” by Edward B. Burger and Michael Starbird a total of 20 times since Spring 2001. The students in this class have almost all been in non-technical majors and many started the semester with negative or ambivalent attitudes toward mathematics based on their prior experiences. The author has gathered responses from students in this class that illustrate significant changes in their attitudes towards mathematics during the course. In particular, the responses gathered at the end of the semester are often eloquent about understanding the great ideas of mathematics that students confronted in this course and about seeing many more and varied connections between mathematics and the “real world” than they had previously realized existed.

The NPDGamma experiment measures the parity-violating (PV) gamma asymmetry from polarized cold neutrons captured on protons at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The (PV) neutron spin asymmetry A γ of photons from polarized cold neutron capture on protons is proportional to the ΔI=1 long range weak meson coupling $h_{\pi }^{1}$ between nucleons in the hadronic weak interaction (HWI). Liquid para-hydrogen production data taking concluded in April 2014 and once the background aluminum asymmetry measurements are complete, the PV asymmetry A γ can be extracted. Preliminary results of the analysis of A γ are presented.

Background Cytomegalovirus (CMV) disease typically occurs during the first year after solid organ transplantation, after cessation of antiviral prophylaxis. CMV occurring after the first year is uncommon and not well described. Methods We conducted a case–control study to identify potential risk factors and a retrospective cohort study to evaluate 1-month mortality in solid organ transplant (SOT) recipients who developed CMV disease after the first year post transplant, or “very late CMV” (VLCMV), compared with those developing CMV within the first year (CMV Y1), adjusting for demographics, donor and recipient CMV serostatus, immunosuppression, rejection, and co-morbidities. Results We identified 85 SOT recipients with CMV disease at a single transplant center between January 2006 and October 2008: 23 (27%) had VLCMV and 62 (73%) had CMV Y1. Heart transplantation was independently associated with increased risk (adjusted odd ratio [OR] 4.11; 95% confidence interval [CI] 1.34–12.61; P = 0.01) for VLCMV. Patients with VLCMV had increased 1-month mortality (unadjusted OR 5.39; 95% CI 1.06–27.48; P = 0.02). Mortality was uncommonly attributable to CMV. Conclusions CMV disease continues to occur after the first year post solid organ transplantation, particularly in heart transplant recipients, and can be associated with poor outcomes. CMV should be suspected in patients with symptoms or laboratory findings consistent with CMV, even if the patients present >1 year post transplant.

We describe a method by which students in an abstract algebra course can discover classical theorems before they are stated and proved, with the help of leading questions and the software Groups, Algorithms and Programming (GAP) [1].

In this paper we develop a theory for computing the nonabelian tensor square and related computations for finitely presented groups and specialize it to polycyclic groups. This theory provides a framework for making nonabelian tensor square computations for polycyclic groups and is the basis of an algorithm for computing the nonabelian tensor square for any polycyclic group.

Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many body physics. Unfortunately, the pair correlation function $g(r)$ inferred from neutron scattering measurements of the differential cross section $d\sigma \over d\Omega$ from different measurements reported in the literature are inconsistent. We have measured the energy dependence of the total cross section and the scattering cross section for slow neutrons with energies between 0.43~meV and 16.1~meV on liquid hydrogen at 15.6~K (which is dominated by the parahydrogen component) using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. The relationship between the neutron transmission measurement we perform and the total cross section is unambiguous, and the energy range accesses length scales where the pair correlation function is rapidly varying. At 1~meV our measurement is a factor of 3 below the data from previous work. We present evidence that these previous measurements of the hydrogen cross section, which assumed that the equilibrium value for the ratio of orthohydrogen and parahydrogen has been reached in the target liquid, were in fact contaminated with an extra non-equilibrium component of orthohydrogen. Liquid parahydrogen is also a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. We describe our measurements and compare them with previous work., Comment: Edited for submission to Physical Review B

In this paper we compute the non-abelian tensor square for the free 2-Engel group of rank $n>3$. The non-abelian tensor square for this group is a direct product of a free abelian group and a nilpotent group of class 2 whose derived subgroup has exponent 3. We also compute the non-abelian tensor square for one of the group’s finite homomorphic images, namely, the Burnside group of rank $n$ and exponent 3.AMS 2000 Mathematics subject classification: Primary 20F05; 20F45. Secondary 20F18

We discuss some of the progress that has occurred since the survey article ``Nonabelian tensor products of groups: the commutator connection'' by L.C. Kappe appeared in the Proceedings of Groups St Andrews 1997 in Bath, with a particular emphasis on non-abelian tensor squares of groups. We survey methods for computing non-abelian tensor squares, results that support such calculations, and recent general structure results.

Let n be an integer greater than 1, and let G be a group. A subset {x 1, x 2, ..., x n } of n elements of G is said to be rewritable if there are distinct permutations \( \pi \) and \( \sigma \) of {1, 2, ..., n} such that¶¶\( x_{\pi(1)}x_{\pi(2)} \ldots x_{\pi(n)} = x_{\sigma(1)}x_{\sigma(2)} \ldots x_{\sigma(n)}. \)¶¶A group is said to have the rewriting property Q n if every subset of n elements of the group is rewritable. In this paper we prove that a finite group of odd order has the property Q 3 if and only if its derived subgroup has order not exceeding 5.

A covering of a group is a finite set of proper subgroups whose union is the whole group. A covering is minimal if there is no covering of smaller cardinality, and it is nilpotent if all its members are nilpotent subgroups. We complete a proof that every group that has a nilpotent minimal covering is solvable, starting from the previously known result that a minimal counterexample is an almost simple finite group.

Let n be an integer greater than 1, and let G be a group. A subset {x1, X2, ..., xn} of n elements of G is said to be rewritable if there are distinct permutations π and σ of {1,2, …, n} such that The group G is said to have the rewriting property Qn or to be n-rewritable, if every subset of n elements of G is rewritable. The main result of this paper shows that the only nontrivial semlsimple groups with the property Q5 are the alternating group A5, the symmetric group S5, the projective special linear group PSL(2, 7) and the projective general linear group PGL(2, 7)

Let n be an integer greater than 1, and let G be a group. An n -tuple x 1 , x 2 ,… x n of elements of G is called rewritable if there is a nontrivial permutation π of {1,2…, n } such that x 1 x 2 … x = x π (2)⋯ x π (π) . the group G is said to have the rewriting property P n if every n -tuple of G is rewritable. The authors have previously shown that all groups with P 7 are soluble, whereas the alternating group A 5 has P 8 . Thus the least n for which P n contains a nonabelian simple group is 8. In this article the authors confirm conjectures of R. Brandl concerning the structure of insoluble groups with P 8 . In particular, let G be an insoluble group. Then G has the rewriting property P 8 if and only if it is a semidirect product H ⋉ K where H is abelian. K is isomorphic with the alternating group of degree 5, and | H : C H ( K )| = 1 or 2.

We provide a detailed structure description of the derived subgroups of the free nilpotent groups of finite rank. This description is then applied to computing the nonabelian tensor squares of the free nilpotent groups of finite rank.

Particle detection instrumentation to address the in vivo verifications of proton dose and range is under development as part of a proton therapy research program focused on patient quality assurance. For in vivo proton range verification, a collimated gamma detector array is under construction to indirectly measure the position of the Bragg peak for each proton beam spot to within 1–2 mm precision. For dose flux verification, a proton fluence detector based on the technology of the Micromegas is under construction. This detector has an active area of about 100 cm2, coordinate resolution of better than 1 mm, and handling of incident proton beam fluxes of 109–1013 particles/s.

It is argued that applying formal methods to standards making would result in more accurate, more understandable, and more useful standards. The main benefit seen in using formal methods in a standard's development and expression is improving the standard's quality. In the early stages of standards development, formal methods can result in considerable clarification during the development and expression of the underlying conceptual model for a standard or family of related standards. They can also define precisely the relation among the components of both the standard being developed and other standards. Later in the development process, formal methods can improve a standard's quality during its use by letting it be expressed clearly, unambiguously, and concisely in a way that natural language does not allow. Finally, formal methods can aid standards development at the maintenance stage, for example, by allowing the adequacy of a proposed change to be proved. Guidelines for applying formal methods in the standardization process are provided. >

EDITOR—The anonymous personal view shows how isolating secrecy in donor assisted conception can be and why every step should be taken to stop the practice of donor anonymity, as has already occurred in several countries.1 My main purpose in writing is to comment on the statement that “the few studies that have looked at us [donor conceived children] have used only parental interpretations of our emotional state.” This is largely true if the search for research is confined to the standard sources, such as Human Reproduction and Fertility and Sterility (although Human Reproduction has published one research paper that has directly sought the views of donor conceived people themselves2).3 A few other studies have sought the experiences of donor conceived people directly but have not been published (G Hewitt, unpublished paper, Sydney, 2001; L W Spencer, unpublished MA thesis, Detroit, 2000). Interestingly, all of the …

The particle-composition (0.15 to >64 mm) of the stream-bed was monitored by Surber sampling at sites above and below the site of the Thomson Dam during the two years of most active construction. Levels of particles between 0.5−2 mm were highest 9.5 km below the dam site, and increased throughout the study. Levels of these grades at sites above and well below the dam site were variable, but showed no consistent trends. Material greater than 2 mm showed no substantial variation either over time or between sites spanning approximately 70 km of river length and 250 m of elevation. Artificial substratum samplers were used to estimate the rate of sediment input (0-2 mm) between sampling dates. Sediment input was clearly highest 1 km and 9.5 km below the dam site. Input was seasonal, with maxima in winter and spring of each year. Size classes 1-2 mm and

Summary The emergency management of a patient presenting in respiratory failure due to critical tracheal stenosis caused by an intratracheal foreign body is described. The use of an extracorporeal oxygenator in the anaesthetic management of the patient is highlighted.

Let n be an integer greater than 1. The group G has the property Q„, or is n-rewritable, if for each «-element subset ﹛x1 x 2… ,x n﹜ of G, there exist permutations such that If one of ᓂ,τ can always be chosen to be the identity, then G has Pn, or is totally n-rewritable. We also use Pn and Qn to denote the classes of groups having these properties. Making use of the obvious inclusions, we define

Aquatic macroinvertebrates were sampled above and below the site of the Thomson Dam, Victoria, Australia, over a two-year period during dam construction. Total number of species and the number of species and individuals per sample were all lower for 33 km below the dam site, compared with sites upstream. Ordination analysis showed that the major differences between the study sites were related to longitudinal position in the river. The second ordination axis could be related to seasonal changes in the fauna. Variations in the pattern of axis 2 scores at sites downstream of the damsite suggested continuing changes in the community at these sites during the study, possibly due to increases in the density of species favoured by sediment deposition (e.g. Cheumatopsyche sp. 2: Trichoptera, Hydropsychidae). Classification analysis separated the faunal communities at sites above and below the construction zone. Inverse classifications indicated species with disjunct distributions on either side of the dam site. By comparison with preconstruction data and surrounding undisturbed rivers, species likely to have been disadvantaged by increased sedimentation were identified. These included Atalophlebioides sp. 1 (Ephemeroptera, Leptophlebiidae), Stenoperla australis (Plecoptera, Eustheniidae) and Scirtidae (Coleoptera).

In any study of Canadian industry today, words such as growth and development quickly come into their own. The very scope and rapidity of the changes have introduced a new pace which in many ways is unique. Some of the reasons are not hard to trace. Once growth reaches a certain stage it seems to accumulate momentum. The proximity of Canada to the United States and her access to the industrial technology of that country have also contributed greatly.A large measure of the expansion of Canadian industry has been the result of extensions of United States corporate activity into Canada through the establishment or development of branches and subsidiaries. In this manner, United States industrial technology, supported by abundant sources of financing in that country, has speeded and extended the process of Canadian development. And important parts of the growth which provide sources of supply for United States industry are in turn closely linking Canadian growth to growth in the United States economy. Participation by British and European enterprise and industry to a greater degree than formerly should also be noted, although it is much smaller in scale than the parts sponsored by United States industry. The pace of development would have been much slower had there not been this borrowing of non-resident resources both technological and financial. In the past half-dozen years or so, over half the increase in investment in Canadian industry has been owned by non-residents. That suggests the degree of financial assistance. It would be very difficult to evaluate the borrowing of technology but in some industries it has been very great and has provided the indispensable “know-how” without which ventures would carry much greater risks. Most of this increased investment has taken the form of equity ownership and control which carries with it potential claims to participate in subsequent growth in the rapidly developing, commodity-producing industries—manufacturing and mineral production.

One of the effects of the war upon Canadians has been to make us more conscious of our international financial relations. The rapid changes during the war, bringing with them problems which demanded immediate solutions, have radically altered Canadian economic relations with the rest of the world, and have made for a new awareness of the implications of these changes and the new responsibilities accompanying them. The war showed how adaptable nations can be under the pressure of circumstances, but the ability of human beings under pressure to adapt themselves to their environment often outruns their ability to understand thoroughly what is happening, and to make the more fundamental adjustments which new situations require. The full significance of war-time changes on our balance of payments and international position will probably not be entirely clarified for some time to come, but new potentialities have been revealed of previously unplumbed depths of capacity.Along with the revelations of productive capacity came new experience with the financial aspects of Canada's international economic relations and the currency problems which are inherent in the structure of the Canadian balance of payments. Being closely allied to internal finance and the larger questions of the economic mobilization of total war, these international financial factors may have been overshadowed at times. But the full significance of the war-time international relations of the Canadian economy should not be overlooked, for they clearly show the extent to which full use of Canadian productive facilities is dependent upon external and special demand, and provide further evidence of how closely geared general activity in Canada is to exports. Studies of national income and expenditure show the place which the net export of goods and services has in the maintenance of national economic activity. So long as the Canadian economy maintains its present structure, it will be highly dependent upon the stimulus of external demand, since income generators like internal investment and consumption do not appear to have the potentialities under present circumstances which would permit them in themselves to maintain Canadian production at a high level.

Synopsis The paper summarises the limited literature on crinoid ecology and palaeoecology and attempts to interpret the depositional environment of certain British crinoidal sediments in the light of experimental observations. Three types of crinoidal limestone are recognised: muddy limestones deposited in shallow, sheltered waters; poorly washed limestones formed in deeper, open conditions; and clean-washed limestones which may derive in part from the reworking of one or other of the first two types.

A technique of insertion of permanent endocardial pacing electrodes via the infraclavicular subclavian vein is described. Twenty-eight electrodes have been inserted without a displacement or any of the recognized complications occurring. The method is quicker and more reliable than more conventional approaches. We feel the low displacement rate is the result of the relatively proximal catheter fixation to the fascia pectoralis and the use of tined electrodes.

We have built a Shectman-type photon-counting spectrometer based on the Latham-Geary “Z-Machine” design. The system is innovative in that the entire system rides on the telescope and communicates to the outside world via standard serial lines. Microprocessor architecture, memory controllers and new interconnect and packaging technologies have been employed. The system is portable and can be easily connected to almost any computer. It is suitable for calibrated spectrophotometry on a smaller telescope as well as for conventional spectroscopy.

Objective: To examine whether intrapartum care and delivery of low risk women in a midwife managed delivery unit differs from that in a consultant led labour ward. Design: Pragmatic randomised controlled trial. Subjects were randomised in a 2:1 ratio between the midwives unit and the labour ward. Setting: Aberdeen Maternity Hospital, Grampian. Subjects—2844 low risk women, as defined by existing booking criteria for general practitioner units in Grampian. 1900 women were randomised to the midwives unit and 944 to the labour ward. Main outcome measures: Maternal and perinatal morbidity. Results: Of the women randomised to the midwives unit, 647 (34%) were transferred to the labour ward antepartum, 303 (16%) were transferred intrapartum, and 80 (4%) were lost to follow up. 870 women (46%) were delivered in the midwives unit. Primigravid women (255/596, 43%) were significantly more likely to be transferred intrapartum than multigravid women (48/577, 8%). Significant differences between the midwives unit and labour ward were found in monitoring, fetal distress, analgesia, mobility, and use of episiotomy. There were no significant differences in mode of delivery or fetal outcome. Conclusions: Midwife managed intrapartum care for low risk women results in more mobility and less intervention with no increase in neonatal morbidity. However, the high rate of transfer shows that antenatal criteria are unable to determine who will remain at low risk throughout pregnancy and labour.

The multiplicity distributions of charged particles in restricted rapidity intervals in Z0 hadronic decays measured by the DELPHI detector are presented. The data reveal a shoulder structure, best visible for intervals of intermediate size, i.e. for rapidity limits around +/- 1.5. The whole set of distributions including the shoulder structure is reproduced by the Lund Parton Shower model. The structure is found to be due to important contributions from 3- and 4-jet events with a hard gluon jet. A different model, based on the concept of independently produced groups of particles, “clans”, fluctuating both in number per event and particle content per clan, has also been used to analyse the present data. The results show that for each interval of rapidity the average number of clans per event is approximately the same as at lower energies.

We have built a Shectman-type photon-counting spectrometer based on the Latham-Geary “Z-Machine” design. The system is innovative in that the entire system rides on the telescope and communicates to the outside world via standard serial lines. Microprocessor architecture, memory controllers and new interconnect and packaging technologies have been employed. The system is portable and can be easily connected to almost any computer. It is suitable for calibrated spectrophotometry on a smaller telescope as well as for conventional spectroscopy.