Trunk Systems Research Articles

Hamstring stretching significantly changes the sitting biomechanics

The tightened hamstring connecting the tibia to the pelvis provides more posterior pelvic tilting and consequent backward curvature of the sacral and lumbar vertebrae. Therefore, the study goal was to quantitatively investigate the effect of hamstring and low back stretching on the trunk biomechanics in a system-level perspective. Twelve healthy subjects performed two stretching interventions (hamstring only (HS); hamstring + low back (HLS)) for 40 s on two separate days. They sat on a stool before and after the intervention while capturing trunk kinematics and EMG. In addition, the lumbar flexion angle at which the L4 paraspinals deactivate (i.e., flexion-relaxation phenomenon; FRP) was monitored while trunk flexion-extension trials, performed before and after the protocol. The FRP onset angle was captured to verify the biomechanical changes in the lower extremity and trunk systems. In the results, the stretching intervention significantly increased the reaching distance by 6.3 cm in the sit-and-reach test performed immediately before and after the intervention. The flexible hamstring improved the lumbar flexion angle and head postures in both the HS and HLS. However, the HLS induced laxity in lumbar passive tissues, as confirmed by changes in the FRP, and significantly increased co-activation in the low back. The stress-relaxation of the hamstring and surrounding passive tissues could help to maintain better lumbar flexion angle (i.e., lumbar lordosis) while sitting. Periodic HS for 40 s without any significant lumbar flexion may be recommendable for office workers who sit for long periods.

Quantifying the protective capacity of mangroves from storm surges in coastal Bangladesh.

Mangroves are an important ecosystem-based protection against cyclonic storm surge. As the surge moves through the mangrove forest, the tree roots, trunks, and leaves obstruct the flow of water. Damage to adjacent coastal lands is attenuated mainly by reducing (i) surge height, which determines the area and depth of inundation and (ii) water flow velocity. But the extent of mangrove protection depends on the density of tree plantings and the diameter of trunks and roots, along with an array of other forest characteristics (e.g., floor shape, bathymetry, spectral features of waves, and tidal stage at which waves enter the forest). Making efficient use of mangroves’ protective capacity has been hindered by a lack of location-specific information. This study helps to fill that gap by estimating reduction in storm surge height and water flow velocity from mangroves at selected sites in cyclone-prone, coastal Bangladesh. A hydrodynamic model for the Bay of Bengal, based on the MIKE21FM system, was run multiple times to simulate the surge of cyclone Sidr (2007) at the Barisal coast. Estimates of surge height and water flow velocity were recorded first without mangroves and then with mangroves of various forest widths and planting densities, including specific information on local topography, bathymetry, and Manning’s coefficients estimated from species’ root and trunk systems. The results show a significant reduction in water flow velocity (29–92%) and a modest reduction in surge height (4–16.5 cm). These findings suggest that healthy mangroves can contribute to significant savings in rehabilitation and maintenance costs by protecting embankments from breaching, toe-erosion, and other damage.

Paleovalley fills: Trunk vs. tributary

A late Mississippian–early Pennsylvanian eustatic sea level drop resulted in a complex lowstand drainage network being eroded across the Illinois Basin in the eastern United States. This drainage system was filled during the early part of the Pennsylvanian. Distinct differences can be recognized between the trunk and tributary paleovalley fills. Fills preserved within the trunk systems tend to be fluvially dominated and consist of bed-load deposits of coarse- to medium-grained sandstone and conglomerate. Conversely, the incised valleys of tributary systems tend to be filled with dark mudstone, thinly interbedded sandstones, and mudstones and siltstones. These finer grained facies exhibit marine influences manifested by tidal rhythmites, certain traces fossils, and macro- and microfauna. Examples of tributary and trunk systems, separated by no more than 7 km (4.3 mi) along strike, exhibit these styles of highly contrasting fills. Useful analogs for understanding this Pennsylvanian system include the Quaternary glacial sluiceways present in the lower Ohio, White, and Wabash river valleys of Indiana (United States) and the modern Amazon River (Brazil). Both the Amazon River and the Quaternary rivers of Indiana have (or had) trunk rivers that are (were) dominated by large quantities of bed load relative to their tributaries. The trunk valley systems of these analogs aggraded much more rapidly than their tributary valleys, which evolved into lakes because depositional rates along the trunk are (were) so high that the mouths of the tributaries have been dammed by bed-load deposits. These Holocene systems illustrate that sediment yields can significantly influence the nature of fill successions within incised valleys independent of rates of sea level changes or proximity to highstand coastlines.

Automated software development based on composition of categorized reusable components—construction and sufficiency of skeletons for batch programs

AbstractIn this paper the authors discuss approaches to the automation of software development in use during the past 20 years for trunk business systems, in particular categorized reusable components, the center of this method's technology. First an outline of the software in question, the development environments, and approaches to automation is given. With respect to the major automation methods, the structure of methods for categorized reusable components, a structural element, and the design of skeletons for batch programming are described. This approach uses (1) input and output component groups, (2) program skeleton groups, and (3) data processing groups for which detailed processes have been turned into components, all in a mutually independent fashion as categorized reusable components for the software to be generated. Then these components are adjusted and a program is generated by combining them together using tools. By making the components independent in this fashion, this approach has the capacity to create X*Y*Z structures overall even with only X, Y, and Z components each. In addition, the 24 skeletons developed during this research are demonstrated to cover 90% of large‐scale trunk systems, and the top 10 skeletons over 70%. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(6): 50–66, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10057

Lower and lower Middle Pennsylvanian fluvial to estuarine deposition, central Appalachian basin: Effects of eustasy, tectonics, and climate

Interpretations of Pennsylvanian sedimentation and peat accumulation commonly use examples from the Appalachian basin because of the excellent outcrops and large reserve of coal (>100 billion metric tons) in the region. Particularly controversial is the origin of Lower and lower Middle Pennsylvanian quartzose sandstones; beach-barrier, marine-bar, tidal-strait, and fluvial models all have been applied to a series of sand bodies along the western outcrop margin of the basin. Interpretations of these sandstones and their inferred lateral relationships are critical for understanding the relative degree of eustatic, tectonic, and climatic controls on Early Pennsylvanian sedimentation. Cross sections utilizing >1000 subsurface records and detailed sedimentological analysis of the Livingston Conglomerate, Rockcastle Sandstone, Corbin Sandstone, and Pine Creek sandstone (an informal member) of the Breathitt Group were used to show that each of the principal quartzose sandstones on the margin of the central Appalachian basin contains both fluvial and marginal marine facies. The four sandstones are fluvially dominated and are inferred to represent successive bed-load trunk systems of the Appalachian foreland. Base-level rise and an associated decrease in extra-basinal sediment at the end of each fluvial episode led to the development of local estuaries and marine reworking of the tops of the sand belts. Each of the sand belts is capped locally by a coal, regardless of whether the upper surfaces of the sand belts are of fluvial or estuarine origin, suggesting allocyclic controls on deposition. Peats were controlled by a tropical ever-wet climate, which also influenced sandstone composition through weathering of stored sands in slowly aggrading braidplains. Recurrent stacking of thick, coarse-grained, fluvial deposits with extra-basinal quartz pebbles; dominance of bed-load fluvial–lowstand deposits over mixed-load, estuarine-transgressive deposits; thinning of sand belts around tectonic highs and along faults; cratonward shift and amalgamation of successive sand belts on the margin of the basin; and truncation of successive sand belts toward the fault-bound margin of the basin are interpreted as regional responses to Alleghenian tectonism, inferred to have been the dominant control on accommodation space and sediment flux in the Early Pennsylvanian basin.

Control of Trunk Line Systems in Heavy Traffic

The paper deals with the heavy traffic modelling and optimal control of trunk line networks. The controls concern either acceptance or rerouting. Both discounted and ergodic cost functions are used. It is shown that the sequence of optimal value functions of the physical process converges to the optimal value function for the limit model. Also, good controls for the limit system are good for the physical system. Single trunk systems with both priority and other inputs as well as networks are addressed. For the network case, the limit model is nonstandard, since the control occurs only on the boundary, and is a control over the direction of reflection.

Regional Paleotopographic Trends and Production, Muddy Sandstone (Lower Cretaceous), Central and Northern Rocky Mountains (1)

The Muddy Sandstone and equivalent strata have produced more than 1.5 billion bbl of oil-equivalent hydrocarbons. Production is controlled principally by unconformities formed during a relative sea level lowstand. Reservoirs are found in paleohills of older marine sandstones, younger valley fills and associated alluvial plain channel sandstones, and transgressive marine deposits. At least ten paleodrainage basins existed at maximum lowstand. A regional drainage divide formed in southern Wyoming and separated southeast-flowing from northwest-flowing alluvial systems. Local tributaries stripped drainage divides of fine-grained detritus derived from the underlying Skull Creek Shale and older marine sandstones. In contrast, trunk streams carried medium- and coarse grained-sands eroded from eastern, southern, and western provenances of Paleozoic and Mesozoic strata. The best fluvial reservoirs are developed within these coarser grained trunk systems. Reservoir data display little or no correlation between depth and porosity due to secondary dissolution porosity developed at all depths. Valley fill and channel reservoirs have produced at least 359 MMBOE, onlap cycles another 315+ MMBOE, and older marine buried-hill reservoirs more than 268 MMBOE. The best per-field reserves are from marine sandstones. Regional production patterns reflect proximity to mature Skull Creek and Mowry shale source beds and favorable trapping conditions within individual paleodrainages. Future hydrocarbon exploration successes will require drilling to the Muddy Sandstone in deeper basin settings and a better understanding of the role of unconformities and diagenesis in controlling hydrocarbon accumulations.

Comparison of polarization handling methods in coherent optical systems

The authors compare three polarization handling methods in coherent optical systems. These methods are: endless polarization control, polarization diversity, and data-induced polarization switching. These methods are also compared with active, data-synchronous polarization switching. It is seen that endless polarization control is potentially the most powerful candidate, however, the choice of polarization control devices remain questionable. Polarization diversity is as versatile as polarization control and is potentially the fastest method; however, it yields lower receiver sensitivity. Endless control or a well-designed diversity receiver should be used for coherent trunk systems. Data-induced polarization switching is restricted to frequency-shift-keying (FSK) systems. It promises a loss span similar to that of diversity, but is far simpler, which makes it recommendable for FSK distribution systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Lightwave subcarrier CATV transmission systems

The design and performance of multichannel amplitude-modulated (AM) vestigial-sideband (VSB) lightwave cable television (CATV) systems are described. Requirements on linearity and noise are derived, and factors limiting the performance of the laser transmitters and receivers are discussed. For the high-performance lasers the carrier-to-noise ratio and composite second- and third-order distortions are acceptable for video trunk systems. Impairments because of fiber reflections and dispersion and mode partition fluctuations in the laser are discussed. Feedforward, feedback, and predistortion are discussed; difficulties with each prevent immediate application. The use of LiNbO/sub 3/ external modulators and high-power solid-state lasers is considered. The third-order distortion and insertion loss of the modulator more than counteract the high available laser power (100 mW), making this alternative unattractive unless a third-order linearizer can be implemented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

South Carolina: A Geography (review)

Vol. XXVII, No. 2 133 ments the text. Although this work is supported by a useful, detailed 14 page index, bibliographic support is limited to interview references. The more inquisitive reader is referred to two technical reports prepared by the same authors for the U.S. Army Corps of Engineers: Historic Settlement in the Upper Tombigbee Valley (1981) and Historical Geography of the Upper Tombigbee Valley (1982). Tenn-Tom Country is an effective historical geography that admirably fulfills the authors' stated objectives. It belongs on the shelf of every scholar who has an interest in the South. Doubtless it will become one of the baseline surveys against which future impacts of the Tennessee-Tombigbee Waterway may be gauged. Walter Martin, Department of Geography and Earth Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223. South Carolina: A Geography. Charles F. Kovacik andJohn J. Winberry. Boulder: Westview Press, 1987. xviii and 235 pp., maps, photographs, tables, bibliography and index. $45.00 cloth (ISBN-0-89158-987-2) South Carolina: A Geography is the twelfth of thirteen monographs which comprise the Geographies of the United States series from Westview Press. Never intended to encompass all fifty states, the series offers somewhat regionally-grouped selections from New Jersey to Hawaii. Connecticut, Maryland and New Jersey make up entries from the Northeast; Illinois, Michigan, Missouri, Nebraska and Wisconsin represent the Midwest. A forthcoming and final volume on Louisiana will join South Carolina and Texas as entries from the South. Works on Colorado and Hawaii stand as singular departures from the regional clusters. South Carolina is a credit to the collection, an addition which contributes more than its share to the quality of the series. Attention to detail and careful explanation are woven into a highly readable text that presents South Carolina before a broad audience. Kovacik and Winberry employ Sauer's concept ofcultural landscape evolution to identify and synthesize the environmental, cultural, historical and technological dynamics which have culminated in South Carolina's contemporary geography. This approach yields two background 134Southeastern Geographer chapters on the state's physical geography, followed by four chapters on South Carolina's historical geography to 1950, and four chapters on characteristics of the contemporary landscape. Physical contrasts from the narrow Blue Ridge to the broader Piedmont and Coastal Plains form both striking and subtle landform and climatic expressions characteristic to South Carolina's small but diverse area. Subsequent patterns of historical and economic development, as well as resultant cultural landscapes, appear with equal diversity over space and time. The authors build on those differences, comprehensively reconstructing the past geographies that have made a distinctive imprint on the present day landscape. For clarity and synthesis in their presentation, Kovacik and Winberry skillfully divide the state's historical geography into four time periods: 1) the indigenous landscape, from pre-historic time to about 1565, 2) the colonial landscape, 1565 to 1785, 3) the antebellum landscape, 1785 to 1865 and 4) the postbellum landscape , 1865 into the 1940's. Emphasis is given not only to the distinct geography of each period but also to the contributions that each has imparted to the area's present geography. Vestiges from the first period, for example, include Indian place names, plant domesticates that have become southern dietary staples and the apparent origins of barbecue. The cultural background of South Carolina's population, like its economic history is deeply rooted in the experiences of the colonial, antebellum and postbellum periods. These past geographies feature a pattern of successive, at times singular, reliance on one economic enterprise. An economy dominated by indigo and rice was supplanted by the dominance of cotton, then replaced by textiles, tobacco and forestry, all unevenly distributed over space and time. Numerous maps and illustrations provide a clear spatial perspective of these important developmental periods. Chapter endings carefully summarize the ways that the geography of each period has shaped present patterns. Relict features such as trunk systems in former rice-producing areas, abandoned canals and antebellum mansions all remain as reminders of the past. South Carolina effectively interprets the complexity of the past and its imprint on the contemporary landscape. Four chapters of equal length to that of the historical setting provide...

Respiratory system of the primitive moth Micropterix calthella (Linnaeus) (Lepidoptera : Micropterigidae)

The 1st thoracic spiracular atrium is closed by anterior and posterior muscle fibres extending between its dorsal and ventral wall. The 2nd thoracic spiracle has only a single (anterior) closing lip, movable by a muscle inserting on the wall below the spiracular aperture; this configuration may be a lepidopteran ground-plan autapomorphy. There are functional spiracles on abdominal segments I – VII, each with a closing “bow” and “lever”. There are intrinsic occlusor muscles in all abdominal spiracles and the 1st spiracle has an extrinsic (ventral) dilator. Dorsal dilator muscles or ligaments are absent. A dorsal and a ventral tracheal trunk extend from the 1st thoracic spiracle into the head; the latter supplies the mouthparts and the antenna; there is no connection between the dorsal and ventral cephalic trunk systems. There is a single series of lateral connectives between the spiracles of each side. There is a ventral tracheal commissure in both pterothoracic segments, but none in the prothorax. In each pterothoracic segment an anterior and a posterior tracheal arch give off branches to the wing and anastomose with each other on their downwards course into the leg. Wing tracheation is greatly reduced. The anterior and posterior tracheae of each wing are independent of each other. There is a dorsal commissure in abdominal segment VIII; ventral abdominal commissures are lacking in Micropterix, although present in other micropterigid genera. The terminalia are partly supplied from tracheae arising in segment VII. Air sacs occur in the tibiae only. Phylogenetic aspects of holometabolan tracheation patterns are discussed.

Electronic switching for trunk systems

The past decade has seen the worldwide introduction of electronic switching with stored program control. Initially the application of this new technology was in local exchanges but today electronic systems are being introduced into trunk systems as well. One of the latest applications is No. 4 E.S.S., a very large trunk switch. This system, in combination with local systems such as No. 1 E.S.S. and new signalling arrangements, offers major innovations in telecommunication service. The introduction of stored program electronic switching at the local level in the Bell System has led to literally hundreds of new services and features being made available and many more being developed or planned. With stored program control and new signalling arrangements in the connecting trunk systems, the door is opened to both extending the local services and introducing totally new services. These trends are discussed along with examples of possible services. Finally, the effects on development, manufacture, administration, and the customer are reviewed.

Development of 500KV Gas Insulated Switchgear and its Application

The application of Gas Insulated Switchgear (GIS) up to 275kV substations has been proven and the authors have been working jointly on the research and development, with a view of supplying GIS for the 500kV trunk systems in the near future. To demonstrate the reliability and intearity of GIS. a prototype installation was provided and subjected to excess voltage and current during endurance and service tests. The satisfactory results obtained have led to the Kansai Electric Power Co. (KEP CO) Japan placing orders for a 500 kV substation to be commissioned in March 1973. The paper covers some specific engineering problems encountered on 500kV GIS, the results of tests and the investigations of its application.

A Linear Phase Modulator for Large Baseband Bandwidths

A linear phase modulator with a stable carrier frequency would be a useful component in radio systems — especially in coherent phase-shift-keyed PCM systems with baud rates of the order of 100 megabauds per second. The Armstrong modulator appears adequate for these applications; the circuit functions required for its realization are well understood and amenable to the techniques of integrated circuitry. In this paper, an analysis of the signal and distortion properties of the Armstrong circuit and variations of it are presented and applied to three system applications: as a replacement modulator for existing low-index analog systems; for multilevel coherent phase-shift-keyed PCM systems; and for frequency-division frequency-modulation multiplex systems which are of interest in radio trunk systems.

Effect of prlonged tilt on visual orientation.

Visual orientation during lateral tilt is viewed in terms of orientation constancy. The postural systems involved in the maintenance of constancy are considered to be those of the otolith, neck and trunk. The relative contribution of these systems was investigated by obtaining visual verticality judgments immediately upon and several minutes after head, body, and trunk tilts. Due to the apparent non-adaptation of the otolith system any changes in visual orientation resulting from prolonged tilt would be attributed to adaptation of the proprioceptive system stimulated. For 30° head tilt visual orientation over-constancy was reduced by about 2°, reflecting the influence of the neck system. Prolonged body tilts of 30°, 60° and 90° reduced the constancy operating by approximately 1°, 3° and 8°, respectively. This was taken to indicate the contribution of the trunk system, which increased with increasing degrees of body tilt. The above interpretations received strong support from experiments involving trunk tilt, which stimulates only the neck and trunk systems.

The interaction of postural systems in visual orientation

Visual orientation judgments were made during right head tilt, left body tilt, and left trunk tilt, each of 30 deg. In these postures the otolith, neck, and trunk systems are stimulated in pairs. The hypothesis that the visual vertical during trunk tilt is equal to the algebraic sum ofthose in the same direction ofbody tilt and the opposite head tilt was tested and accepted. This result demonstrates the interaction of these postural systems in visual orientation, and complements the confirmation of the same hypothesis for the visual aftereffect following prolonged tilt.

Sedimentation in Arctic Waters: ABSTRACT

Bottom studies involving physiography, sedimentation, and paleontology indicated that there was pre-Pleistocene fluvial erosion when the land stood higher relative to sea level, followed by modification of trunk systems by valley glaciers, then submergence of much of the archipelago, and finally emergence. Tertiary headlands are still submerged more than 400 meters. Following these physiographic and crustal events, Arctic sedimentation occurred. Sediments from lake, river, delta, protected bay, channel, and ocean environments were studied. River and delta environments were selected as classical depositional sites, and others were interpreted from this norm. In fluvial deposits, a direct relationship of decrease in size of detritus with distance of transport occurs together with reduction in percentage, mean size, and number of heavy mineral species. Where river gradients lower abruptly, sedimentary particles decrease immediately from gravel to sand and silt. In deltas, decrease in size is exponential with distance of transport, and deposits consist chiefly of silt and mud. There, contours on lithofacies maps protrude seaward over bathymetric contours indicating prograding of clastic sediments due to marine regression or relat ve crustal uplift. Offshore, no progressive variation in texture exists, due to occurrences of ice-rafted material and lack of sufficient currents. Where currents exist, as in mid-channel areas, sediments are better sorted. Thus, anomalous distributions of sediments arise wherein nearshore deposits in channel areas consist of fine material, but in mid-channel areas they are coarser. Occurrences of coarse marine sands off seaward tips of islands are End_Page 355------------------------------ due to reworking of the submerged clastic Beaufort Formation cropping out along the western Arctic coast, and to occurrences of drowned headlands consisting of unconsolidated coarse materials. Spectrochemical analyses indicate that certain elements and clay minerals in bottom sediments are related to nearby geological formations and that the clay minerals are detrital. This indicates past rigorous physical conditions with negligible chemical activity. End_of_Article - Last_Page 356------------

Frequency patterns for multiple-radio-channel routes

In radio trunk systems a number of two-way radio channels are used over a common route with repeaters provided at intervals. Each radio channel carries a baseband signal by frequency modulation of the radio carrier frequency. The baseband signal may consist of an assembly of single-sideband telephony channels and/or a television channel.When choosing the frequency pattern for the radio channels, selectivity requirements are found to arise, not only from the primary fact that the channels are adjacent in the frequency spectrum, but also from secondary features of the equipment such as, for instance, the intermediate frequency used in the heterodyne repeaters.The paper considers the effects which give rise to such selectivity requirements and shows how to choose the channel frequency pattern and the intermediate frequency to minimize the selectivity requirements. The choice takes account of amplitude non-linearity in waveguide circuits. The presence of this was expected on theoretical grounds and has been confirmed by measurements.A specific frequency pattern is worked out for a route with six two-way channels in which each radio channel can carry at least 600 telephone channels or a single television channel. This arrangement was adopted by the C.C.I.R. in 1956.

Apparatus for the measurement of non-linearity in television trunk systems

Apparatus for the measurement of non-linearity in television trunk systems

Apparatus for the measurement of non-linearity in television trunk systems

The paper describes the normal methods of measuring non-linearity, using sawtooth and staircase waveforms, and it outlines their short-comings. Two systems that overcome these difficulties are described, and their uses are compared with particular reference to television-type waveforms (containing a d.c. component).Reference is made to that particular form of non-linearity in which the ratio of the synchronizing-signal amplitude to that of the picture signal is altered by the transmission system.