Experimental Branches Research Articles

Origin of the frequency branch γ of the de Haas-van Alphen effect in CeSn 3

CeSn 3 is a typical heavy-electron compound which belongs to the valence-fluctuation regime. The major experimental frequency branches of the de Haas-van Alphen effect are explained reasonably well by the large hole sheet and the large electron sheet of the Fermi surface which are derived on the basis of an itinerant 4f-electron model. In particular, it is shown by visualizing the extremal electron orbits that one of the major experimental frequency branches, i.e., the branch γ, can be explained by those orbits which run through the small hollow on the large electron sheet.

Impact of Internal Auditing on Branch Bank Performance: A Field Experiment

We conducted an experiment to assess the contribution of internal auditing to organizational effectiveness. We randomly assigned 224 bank branches to experimental conditions (audited or not audited) and monitored their performance for a year. Performance significantly improved during the half year following the audit in the experimental branches, in contrast to a decline in the control branches due to poor general business conditions. The contribution of auditing to performance is discussed in terms of learning, motivation, deterrence, and process improvement.

Fermi Surface of Th within Local-Density Functional Theory

The energy band structure, particularly the Fermi surface, is calculated for fcc Th by a self-consistent, relativistic augmented-plane-wave method with the exchange and correlation potential in a local-density approximation. The extremal cross-sectional area of the Fermi surface is calculated carefully as a function of the direction of the normal on the {100} and {110} planes, which has been so far calculated only in three high-symmetry directions, and compared with the experimental results for the de Haas-van Alphen (dHvA) effect measured by Boyle and Gold (1969). As a result, it becomes possible to identify the origin of many dHvA frequency branches much more clearly. In addition, a new assignment of the theoretical and the experimental dHvA frequency branches is proposed, and the existence of several new dHvA frequency branches is predicted also.

Performance of Symydobius americanus (Homoptera: Aphididae) on paper birch grazed by caterpillars

Abstract. The potential for host plant‐mediated interactions between leaf‐chewers and the aphid Symydobius americanus on paper birch (Betula papyrifera) was investigated experimentally. Datana ministra and Malacosoma disstria caterpillars were caged on randomly chosen, undamaged branches until they had eaten 30–50% of the leaf area. Control branches received cages but no larvae. Alates of S.americanus were than caged on the experimental and control branches to assess the effect of chewing damage on colony performance. Chewing damage had no detectable effect on initiation of alate reproduction, development time, mortality of nymphs or colony growth rate.

Housing the Loom, 1790-1850: A study of industrial building and mechanisation in a transitional period

The architecture of the textile mill changed radically during the late 18th and 19th centuries. Influences affecting mill design included the way in which production was organised and the degree to which processes were mechanised. This article examines how the industry developed new building types to accommodate looms. In the early period, handlooms were frequently concentrated in distinctive loomshops. The powerloom, introduced in the early 19th century, presented new problems, and in an experimental period different branches of the industry developed different means of housing the new machines. The single-storeyed shed was the dominant building type adopted for powered weaving, but there were in the silk and tape branches prominent examples of factories in which powerlooms were housed in purpose-built multi-storeyed mills.

Branch architecture of sagebrush and bitterbrush: use of a branch complex to describe and compare patterns of growth

The concept of the modularity of plant growth form was incorporated with the fates of buds and used as a framework to describe the typical branch-level developmental morphology of sagebrush (Artemisia tridentata ssp. vaseyana (Rydb.) Beetle) and bitterbrush (Purshia tridentata (Pursh) D.C.). Typical branches included one 2-year-old long shoot and all 1-year-old long shoots originating from that twig. Growth patterns were examined by position along each long shoot within the experimental branches. Shoot fates were recorded for each node and biomass production was estimated. Both species had specific locations where vegetative long shoot production was higher than any other location within the experimental branches. Sagebrush had an overall linear (excurrent) growth form, with the leader long shoot much larger than lateral long shoots. Sagebrush produced many lateral long shoots and few short shoots. In contrast, bitterbrush had a branched (decurrent) growth form, with few long shoots and many short shoots. The leader rarely grew and was no larger than laterals. Knowledge of the location, frequency, and size of vegetative long shoot production within a branch complex provides an understanding of the repeated structure of plants. The branch-level approach provides the information necessary before the effects of environmental factors on growth patterns can be determined. Key words: Artemisia tridentata ssp. vaseyana (Rybd.) Beetle, branch architecture, bud fates, developmental morphology, Purshia tridentata (Pursh) D.C., shrub.

Electronic Structure and Fermi Surface of LaCu6

The electronic energy band structure has been calculated for LaCu 6 , a reference material for the heavy-fermion compound CeCu 6 , by using a relativistic linearized APW method with the exchange-correlation potential in the local-density approximation. LaCu 6 is a compensated metal. It is shown that the Fermi surface consists of many electron and hole sheets in four bands, and holds a lot of the extremal cross sections in various directions. They can explain origins of the major experimental dHvA frequency branches reasonably well, but fails to agree with the experimental frequencies in the low frequency region, perhaps because of limitations of the MT approximation and/or the local density approximations. It is suggested that many dHvA signals may have been missed in the previous measurements.

A Field Tests of Interspecific Competition on Oviposition of Gall‐Forming Sawflies on Willow

We performed a manipulative field experiment to test for competitive effects of the stem galling sawfly (Euura lasiolepis) on three other gall—forming sawflies on arroyo willow (Salix lasiolepis). Within a willow clone, three branches were left untreated, three branches had E. lasiolepis females placed on them in nylon screen bags during that species' oviposition period, and three branches were bagged during that same period but had no sawflies introduced. When oviposition by E. lasiolepis was completed, bags were removed, and three other sawflies were permitted to oviposit on the branches. We found no significant interspecific competitive effects on the densities of three species in response to 9— and 17—fold increase in densities of galls of the stem—galling sawfly on branches of field plants in 1985 and 1986, respectively. The densities of stem gallers on the experimental branches were high, but were near densities observed on some unmanipulated field plants. The density of the petiole galler in 1985 was higher on branches with the stem galler than was the density of the leaf galler. This suggested a facilitation effect, which was not repeated in 1986. The leaf folder had significantly greater densities than the leaf galler or petiole galler. However, bagging of branches resulted in greatly reduced densities of the leaf folder compared to unbagged control branches in both years. The petiole galler and leaf galler were not affected by bagging in either year, probably due to their later oviposition phenology. Within treatment branches, where stem gall densities were high, these three sawfly species did not significantly avoid oviposition on shoots with stem galls, and in 1986 there were generally positive co—occurrence patterns of each of these species with stem galls on shoots. We conclude that interspecific competitive effects on gall density was not important under these field conditions for the leaf galler and the petiole galler, but bagging effects on the leaf folder density could have reduced the likelihood of detecting competitive effects by the stem galler on this species. Differences in the results of this study with an earlier experiment may be related to compensatory ability of the larger field plants and differences in stem gall densities.

Effect of defoliation on tracheid production and the level of indole‐3‐acetic acid in Abies balsamea shoots

To simulate feeding by the spruce budworm (Choristoneura fumiferana Clem.), the apical current‐year shoots on 1‐year‐old branches in the uppermost whorl of 6‐year‐old balsam fir [Abies balsamea (L.) Mill.] trees were either removed completely by debudding before the start of the growing season or defoliated 0, 50, 90 or 100% shortly after budbreak. Debudded branches were treated at the apical end with 0, 0.1 or 1.0 mg of indole‐3‐acetic acid (IAA) (g lanolin)−1. Ninety % of the 1‐year‐old needles were also removed from some of the experimental branches. After ca 4 weeks of growth, the radial width of new xylem and the level of IAA were determined in the 1‐year‐old internode. The IAA content was measured by radioimmunoassay.The removal or defoliation of current‐year shoots inhibited tracheid production and decreased the IAA level. Exogenous IAA stimulated tracheid production and increased the IAA level in debudded branches. Current‐year shoot defoliation also inhibited current‐year shoot elongation. The inhibitory effect of current‐year needle removal on all parameters generally increased with increasing intensity of defoliation. The removal of 1‐year‐old needles did not affect the IAA level or current‐year shoot elongation, nor did it influence tracheid production in branches with current‐year shoots. However, removal of 1‐year‐old needles inhibited tracheid production in debudded branches supplied with exogenous IAA. The results indicate that (1) IAA is involved in the control of tracheid production in the 1‐year‐old internode, (2) IAA is supplied primarily by current‐year shoots, and (3) defoliation by the spruce budworm inhibits tracheid production partly by decreasing the supply of IAA.

A theoretical lattice dynamics model and phonon dispersion measurements for CaSO4(anhydrite)

A lattice dynamics model for ionic crystals with complex anions is developed and applied to experimental phonon dispersion curves for orthorhombic CaSO4. The model treats the sulphate as a rigid unit and includes long-range Coulomb interactions. Fifteen force constants and three atomic charges are fitted to the experimental dispersion branches. The agreement between theory and experiment for all dispersion branches is satisfactory. Additional experimental and theoretical results on the phonon density of states are presented.

The decays of the [formula omitted] β-delayed proton precursors 83Zr, 87Mo and 91mRu

The decays of the nuclides 83Zr, 87Mo and 91mRu have been studied with singles proton counting as well as with pX and pγ coincidences. The half-lives for the three nuclides were measured to be 37.8 ± 1.1 s, 13.3 ± 0.4 s and 7.6 ± 0.8 s, respectively. The proton branch in the decay of 83Zr that populates the first excited state in 82Sr was measured to be (6 ± 4) % of the total delayed proton decay. The corresponding branch in the decay of 87Mo, populating the first excited state in 86Zr was measured to be (15 ± 8) %. Restrictions to the possible spin and parity assignments of 83Zr and 87Mo were deduced from comparisons between the experimental excited-state branches, and those predicted from a statistical model of delayed particle decay. Fits to the endpoints of the delayed proton spectra from 83Zr and 87Mo yielded values of the energy available for delayed proton decay ( Q e.c.− B p) of 2.75 ± 0.10 MeV and 3.7 ± 0.3 MeV, respectively. Comparison between calculated and experimental proton spectra was used as an argument that the source of 91Ru activity is actually a 1 2 − isomer.

Woody Litter Decomposition Following Clear‐Cutting

Unconfined Quercus prinus woody litter of three size classes (0—1, 1—3, and 3—5 cm diameter) was placed on forest floors of a control hardwood watershed and on mesic and xeric sites of a clear—cut watershed at Coweeta Hydrologic Laboratory, North Carolina. Exponential decay coefficients for mass loss on the control were .1524, .1728, and .0912 yr—1 for 0—1, 1—3, and 3—5 cm branches, respectively. Coefficients for 0—1, 1—3, and 3—5 cm branches were. 1752, .0756, and .1644 yr—1 on the mesic and site and .0456, .0948, and .0377 yr—1 on the xeric site. The effect of site differences on decomposition rate was greater than the effect of diameter, although an inverse relationship between diameter and decay coefficient is suggested. Time in the field, temperature, moisture, and microarthropod abundance also appeared to influence decomposition rate. Microarthropods dominated the animal community on decaying wood with oribatid mites and collembolans the most numerous. Microarthropod densities were highest on 0—1 cm twigs and lowest on 3—5 cm branches. Microarthropod densities were generally highest on the control, slightly depressed on the mesic site, and greatly depressed on the xeric site. Time in the field and state of decomposition both positively correlated with microarthropod abundance. Calcium concentration and total calcium exhibited transitory increases but little net change at the end of 1 yr in experimental branches. Total potassium decreased on all sites for 6 mo and for 12 mo on the control and xeric sites, with °60% remaining after 1 yr. Total potassium increased rapidly on the mesic site over the last 6 mo and reached 110% of the initial amount. Temperature, moisture, microbes, and microarthropods appeared to control nutrient dynamics. Wood litter dynamics were more important in terms of nutrient conservation on the clear—cut watershed than on the control and contributed to the resilience of the system. Removal or destruction of woody debris after clear—cutting would decrease the nutrient conservation properties of decaying wood and would probably contribute to watershed output of nutrients.

Developing a Feedback System for Work Units: A Field Experiment in Structural Change

This study examines the effects of introducing an ongoing feedback system into 10 branches of a Midwestern bank. The feedback system was designed to facilitate collaborative control and problem solving in the branches and was hypothesized to raise the level of participation in the branches and increase their effectiveness. The effects of the new feedback system were evaluated by observing its use and by comparing questionnaire and archival information from the experimental branches with similar data collected from 10 branches where the feedback system was not implemented. The results of the study indicated that the new feedback system produced functional consequences in some of the work groups in the experimental branches, but not in others. It appeared that in some cases the consequences were due to an increase in participative control processes, while in others, they were due to an increase in directive management. It is concluded that the effects of different feedback system designs are probably contingent on contextual factors such as the problem-solving skills and orientations of organization members, the nature of the reward systems existing in the organization, and task and individual differences among work units.

Impact of Some Wintering Birds on Spider Abundance in Spruce

An experiment was performed in order to test the hypothesis that the predation by wintering birds appreciably reduces the number of spiders on spruce branches. Autumn levels of the spider populations were measured before the start of the experiment by searching a random sample of spruce branches for spiders. The experimental branches were then enclosed by means of netting, which prevented birds from using them as feeding stations. Two types of nets were used: one coarse type through which spiders but not birds could pass and one fine type with mesh too small even for the spiders. The experiment revealed a significant effect from the elimination of predation

Mirror-Image Twins: The Communities of Science and Technology in 19th-Century America

American technology went through a scientific revolution in 19th century. Technological knowledge was uprooted from its ma- trix in centuries-old craft traditions and grafted onto science. The technological community, which in 1800 had been a craft affair but little changed since middle ages, was reconstructed as a mirror- image twin of scientific community. The artisan was replaced in vanguard of technological progress by a new breed of scien- tific practitioner. For oral traditions passed from master to ap- prentice, new technologist substituted a college education, a professional organization, and a technical literature patterned on those of science. Equivalents were created in technology for experimental and theoretical branches of science. As a result, by end of 19th century, technological problems could be treated as scientific ones; traditional methods and cut-and-try empiricism could be supplemented by powerful tools borrowed from science. This change was most marked in physical sciences and civil, mechanical, and electrical engineering, subject of this paper. But similar changes were taking place at same time in relations of chemistry, biology, geology, and other sciences to their correspond- ing technologies. The result might be termed the scientific revolu- tion in The significance, indeed very existence, of scientific revo- lution in technology has been obscured by a commonly accepted model of relationships between science and technology. In es- sence, this holds that science creates new knowledge which tech- DR. LAYTON, of graduate program in history of science and technology at Case Western Reserve University, is editor of A Regional Union Catalog of Manu- scripts Relating to History of Science and Technology Located in Indiana, Michigan, and Ohio, and author of The Revolt of Engineers: Social Responsibility and American Engineering Profession. This paper was originally presented at symposium on

(1) Rational Approach to Chemical Principles (2) The Elements of Physical Chemistry (3) Physical Chemistry (4) Physical Chemistry

PHYSICAL chemistry emerged as a separate subject at a time when physics and chemistry were separated by a fairly wide terra incognita, and the application of physical and mathematical methods to chemical reactions and equilibria offered an attractive field which Was catered for by neither of the parent sciences. It soon developed a homogeneous subject-matter of its own, which has remained the backbone of physical chemistry courses ever since. It is natural that most of the new methods and fundamental conceptions of the behaviour of matter, which have contributed to the fuller understanding of chemical reactions and modes of combination, should have come from the experimental and mathematical branches of physics, and the role of the physical chemist has been to ensure the immediate and effective application of these methods and conceptions to chemical studies. (1) Rational Approach to Chemical Principles Dr. John A. Cranston. Pp. xii + 211. (London, Glasgow and Bombay: Blackie and Son, Ltd., 1947.) 8s. 6d. net. (2) The Elements of Physical Chemistry Prof. Samuel Glasstone. Third printing. Pp. vii + 695. (New York: D. Van Nostrand Co., Inc.; London: Macmillan and Co., Ltd., 1947.) 25s. net. (3) Physical Chemistry A. J. Mee. Third edition. Pp. xix + 782. (London: William Heinemann, Ltd., 1947.) 20s. (4) Physical Chemistry Dr. E. D. Eastman Prof. G. K. Rollefson. (International Chemical Series.) Pp. viii + 504. (New York and London: McGraw-Hill Book Co., Inc., 1947.) 22s. 6d.

A Treatise on Magnetism, General and Terrestrial

AN observational science like meteorology or terrestrial magnetism is placed in some respects at a disadvantage when compared with the more experimental branches of physical inquiry. It is often difficult to obtain a good and readable account of that which has been done. The reason of this is, that those who are personally engrossed with the science have to deal with such large masses of figures and precise measurements that they are frequently unable to spare the time necessary to give a good historical account of their favourite research. Those again who are the historians of science find it a very formidable task to bring themselves en rapport with all that has been done in such a subject as terrestrial magnetism—in fine, there is not sufficient inducement to undertake the task. No doubt, when such a science is more advanced and has attained a position like that of astronomy, it will find plenty of historians; but in its infancy, and when a good résumé of the progress already made is of peculiar value, it has comparatively few friends. Now these are precisely the circumstances when a Government or a University is able to interfere with very great effect, and with respect to terrestrial magnetism this opportunity has been admirably used by Trinity College, Dublin. The Rev. Dr. Lloyd tells us in his preface that the Dublin Magnetic Observatory was founded and placed under his superintendence by the governing body of Trinity College in 1838. This college has been peculiarly fortunate in having chosen as an observer the eminent physicist who is now its provost, and who, besides reaping much fame as a practical magne-tician, has at length found leisure to present us with the much-required treatise on terrestrial magnetism.