bluuebunny/crossref_metadata_2025 huggingface dataset:
Fats which as linoleic
Authors: Hilditch T. P. , Riley J. P.
Published: July 2007

The mixed fatty acids are first separated into .several group by erystallisation from acetone, and then from light petroleum, at low temperatures, Each group of acids is analysed spectrographically before and after isomerisation with alkali, whence the proportions of α‐elueustearie and linoleic (and, if present, linoleuic) acids are determined. On the mixed fatty acids, the saturated acids are determined by the Bertram method, and palmitie acid by fractionation of the hydrogenated mixed esters. Oleic acid is determined by difference, since iodine values cannot be reliably employed where conjugated fatty acids are involved. With fatty acid mixtures very rich in elaeostearic acid, spectrographic analysis of the total fatty acids may lead to errors in the determined proportions of linoleic and other acids, and the preliminary low‐temperature resolution into several groups is essential.

Two specimens of tung oil and the seed oils of Parinarium macrophyllum, Ricinodendron africanum, and Telfairia accidentalishave been studied by this procedure. All the oils contain elacostearic glycerides in varying proportions, but in no case was linolenic acid present. Saturated, especially palmitic, acids increase parallel with decrease, in the proportion of elacostearie acid, but the greater part of diminution in elaeostearic acid content is made up by increases in oleic and/or linoleic acid.

The technical possibilities of the three Nigerian seed oils mentioned are discussed.
A simple laboratory falling‐film molecular still
Authors: Farmer E. Harold , Sutton D. A.
Published: July 2007

A robust and easily operated falling‐film molecular still in glass, the details of which had evolved over a period of 10 years' use, is described with nil the necessary details regarding construction, accessories and layout. It is of non‐cyclic type, gives a vacuum of 10−5—10−6mm. (as measured an ionisation gauge) in the distillation vessel, and is suitable for laboratory research work in which moderate quantities of material are to be dealt with, it has a wide range of usefulness for the fractionation of mixtures of liquid of differentM., and in straight high‐vacuum distillation, but is unsuitable for use with viscous liquids which do not How, or for mobile liquids which do not spread uniformly over the glass distilling surface, at the desired distillation temperature.
Recent developments in the microbiology of retting. Part II.—The part played by bacteria in retting the flax and in purifying the liquor
Authors: Allen L. A.
Published: July 2007

Bacteria causing soft rot of potato were found to occur consistently in retting liquor and to increase considerably in numbers during the course of a ret. These were mainly spore‐forming anaerobes, though smaller numbers of more‐forming aerobes able to cause soft rot also appeared. Investigation showed that these bacteria were also the causal agents of retting. Continuous aeration of retting liquor encouraged bacterial oxidation of organic matter to carbon dioxide rather than formation of organic acids, thus purifying the liquor sufficiently for it to be re‐used.
Some unsaponifiable constituents of the deodorisation distillates of vegetable oils
Authors: Jasperson H. , Jones R.
Published: July 2007

An examination of the unsaponifiable fraction of the distillates obtained during the industrial process of deodorisation of vegetable oils has revealed the presence in those from groundnut oil, palm oil, cottonseed oil and sunflower seed oil of a high proportion of terpenes accompanied by a smaller proportion of aliphatic hydrocarbons and minor amounts of hydroxy compounds and ketones. In the distillates from palm kernel oil and coconut oil, where there was a preponderance of methyl ketones, the proportions of terpene and aliphatic hydrocarbons were about equal; small quantities of carbinols were associated with the ketones.
The determination of the factor for pyrethrin I in the mercury method
Authors: Bray G. T. , Harper S. H. , Lord K. A. , Major F. , Tresadern F. H.
Published: July 2007

The authors have examined in two series of experiments the effect of varying the conditions under which the reduction of Denigès reagent by chrysanthemum monocarboxylic acid is allowed to proceed. They have shown that both temperature and time of reaction influence appreciably the extent of the reduction; and have confirmed the result previously obtained by Graham and LaForge, that 1 ml. 0·01 M‐potassium iodate solution is equivalent to 5·7 mg. pyrethrin 1 when the reduction takes place, at 25 ± 2° for 1 hour. Differences of 5—6% of the general mean value were shown in the second series despite careful standardisation of conditions.
The use of low ‐ temperature crystallization in the determination of component acids of liquid fats. IV. Marine animal oils. The component acids and glycerides of a grey (atlantic) seal
Authors: Hilditch T. P. , Pathak S. P.
Published: July 2007

Preliminary crystallization of the mixed fatty acids of marine animal oils from acetone at —60°, followed by ether at —30° or —40°, resolves them into groups, differing widely in unsaturation, which can then be esterified and fractionally distilled. This procedure has great advantages compared with the lithium and lead salt separations which were previously employed. The method has been applied to the component acids, and also to the component glycerides, of the blubber oil of a grey seal (Halichoerus grypus). The composition of the fatty acids of seal blubber oil varies over a somewhat wider range than obtains in the fatty oils of some other marine species. The glycerides belong to the extremely ‘“mixed” type characteristic of marine animal oils. The seal liver contained less than 3% of lipids, which consisted of 29%’ phosphatides, 21% unsaponifiable matter and 50% glycerides 5 the liver glycerides contained a less unsaturated mixture of fatty acids than the blubber glycerides and also a higher content of saturated fatty acids.
Rare earth oxides for glass polishing
Authors: Urie R. W. , Wylie A. W.
Published: July 2007

The preparation and properties of glass polishing powders composed of the cerium group of rare earth oxides are described. The oxides arc produced by igniting the corresponding hydroxides, milling the product to break up aggregates and elutriating to remove undesirable residues.
Pilot plant production of rare earth hydroxides and thorium oxalate from monazite
Authors: Urie R. W.
Published: July 2007

A semi‐industrial scale plant for the production of rare earth hydroxides and thorium oxalate from monazite is described. The methods of operation suggested result in yields of products which compare favourably with those obtained in the laboratory. Recommendations on the design and construction of plant equipment are included.
A note on bentonite film as a dielectric
Authors: Kendall J. T.
Published: July 2007

Films obtained by removing the water from colloidal suspensions of bentonite clays were first studied by E. A. Hauser.1 It has been claimed2 that such films, particularly after a further “ waterproofing “ treatment, are suitable for use as condenser dielectrics and insulation, replacing mica. This note briefly gives the results of an investigation into their electrical and other properties.
The influence of basicity upon the efficiency of oxidation/hydrolysis procedures for the separation and purification of cerium
Authors: Vickery R. C.
Published: July 2007

A study of several methods of precipitation of cerium shows that the apparent purity of the precipitate is dependent upon the pH of the solution. An attempt is made to evaluate the efficiency of the varying methods and it is found that the classical nitrate/bromate separation attains the highest efficiency of the procedures examined. The probable formation of a basic chloride during hypochlorite treatment of cerium is noted.
Polyethylene Terephthalate and its early development
Authors: Hardy D. V. N.
Published: July 2007

An account is given of an investigation carried out at the Chemical Research Laboratory, Teddington, on the fibre‐forming polyester, polyethylene terephthalate which was recently announced by the calico Printers' Association and Imperial chemical Industries under the registered name of “Terylene.” The major part of the investigation was carried out under extra‐mural contract with the Ministry of supply, and in collaboration with the Calico Printers' Association, but the latter part was carried out independently. the polyester is obtained from ethylene glycol and methyl terephthalate by ester interchange, and its preparation is covered by B.P. 578079 (Whinfield and Dickson).

To prepare the necessary large of terephthalic acid, p‐cymene was oxidized with nitric acid and the product further oxidized with potassium permanganate to terephthalic acid. This was esterified, and purified by vacuum distilation and subsequent crystallization. The condensation of glycol and methyl terephthalate was carried out both in glass and in metal apparatus: the form of apparatus employed and the conditions of preparation are fully described . Attempts to produce satisfactory filaments by extruding the melt under a high pressure of nitrogen were unsuccesful, partly because the solid polyester suffers degradation when melted and so yields week filaments, and partly because the filaments contain bubbles due to liberation of dissolved nitrogen. Filaments were prepared by extruding the polyester from a glass apparatus immediately after preparation. The filament was cold‐drawn into fibre by passage through two pairs of mechanically driven rolls geared in the ratio of 1:4. The maximum strength of the fibre was 5 g. per denier, and the extension at break was about 12%. The water‐absorption of the fibre was very low, but the dielectric properties were not outstanding. Photomicrographs of filaments and fibres illustrate certain faults which were encountered, and attention is drawn to the fact that although the filament is transparent the fibre is subtantially opaque. The cause of this opacity is discussed.

It is concluded that the maximum strength of polyethylene terephthalate fibre was not reacdhed. The observed properties of the fibre and the fact that it can be produced in metal apparatus suggested that industrial development was desirable. This development was undertaken by Imperial Chemical Industries.
Relationship between fungistatic activity and structure in a series of simple aromatic compounds
Authors: Cavill G. W. K. , Phillips J. N. , Vincent J. M.
Published: July 2007

The fungistatic activity of 127 benzene derivatives is reported and their behaviour related to structure and, in less detail, to solubility. The aromatic nucleus is more effective than its saturated counterpart. The effect of hydrophilic and nitro groups substituted in the benzene ring can differ markedly according to the position of substitution relative to groups already present. Halogen substitution is generally beneficial and is less affected by position. Nuclear substituted 4‐hydroxyhenzoates seem to behave biologically as substituted benzoic acids rather than as substituted phenols. The introduction of alkyl groups and alkyl esterification and etherification are generally beneficial, although the increased activity usually approaches an upper limit in the alkyl series relatively early (three to six carbon atoms). The carboxyl structure of the add and ester appears to be important since the analogous carbonyl compound is definitely less active. Methylene groups between the benzene nucleus and the carboxyl group lower effectiveness.

Although there is evidently a general trend between inhibitory activity and decreasing water solubility, data available for 34 compounds show many deviations from a simple linear relationship between the logarithms of both properties. An approximate ratio between solubilities in ethanol and water (available for 23 compounds) provides a rather more significant relationship. There remain discrepancies, however, for the one organism, as well as between organisms, that suggest the operation of more specific factors than those covered in simple solubility data.
The analysis of pyrethrum flowers
Authors: Mitchell W. M. , Tresadern F. H.
Published: July 2007

It is shown that in the assay of pyrethrum flowers the customary use of warm solvent (soxhlet) gives erroneously high results for pyrethrin II, especially when the higher‐boiling grades of ligroin are used. Cold extraction gives lower results for pyrethrin II, and largely eliminates the variations in the results obtained with different grades of ligroin. It is also shown that cold ligroin extracts all the insecticidally‐active pyrethrins, and that the additional “pyrethrins” extracted by hot ligroin are non‐toxic to house‐flies. Chloroform. is shown to extract a particularly large quantity of such non‐toxic “pyrethrins.” The use of cold ligroin both for the assay, and for the commercial extraction, of pyrethrum flowers is therefore recommended; and it is also suggested that the flowers should be standardized only on their content of pyrethrin I.
The preparation of acenaphthyl ene from acenaphthene. I. Review of possible methods
Authors: Jones J. Idris
Published: July 2007

The literature on the preparation of acenaphthylene is reviewed. In view of conflieting reports, previous work on the caustic fusion of acenaphthene monosulphonic acids is re‐examined and the production of acenaphthylene and polyacenaphthylene is confirmed. By photochemical halogenation of accnaphthcnc I‐chloro‐and I‐bromo‐acenaphthene are obtained in good yield. They spontaneously dehydrohalogenate giving a polymeric form of acenaphthylene.
The role of the heterofermentative lactobacilli in cyder making
Authors: Steuart Dan W.
Published: July 2007

Already in 1879 Johnston and Church taught that lactic acid is the acid of cyder. The writer's experiments in 1934‐36 indicated that lactic acid is the predominating natural acid in English commercial cyders, that it arises usually from the bacterial fermentation of malic acid, and that in some cyders malic acid is probably absent. The lactic bacteria concerned have been investigated abroad, especially in Switzerland.
The volatile constituents of roasted coffee
Authors: Hughes E. B. , Smith R. F.
Published: July 2007

In an investigation into the production of aroma in roasted coffee, some of the principal volatile constituents have been determined. In the staling of coffee only small losses of aldehydes, acetone, and volatile phenols occurred and there was no loss of pyridine or of furfural, despite the volatility of these constituents. Apart from a conversion of diacetyl to acetyl‐methyl carbinol, no change indicating a loss of aroma was discovered. When coffee was prepared for drinking, some losses of volatile constituents were detected. The substance, or substances, giving the characteristic aroma to roasted coffee is as yet unidentified. It is probable that other less volatile substances, that are soluble in light petroleum and are readily oxidizable, are involved in the flavour of roasted coffee.
The peroxidation of diethyl ether and di‐ISOpropyl ether
Authors: Hunter W. , Downing J.
Published: July 2007

Information is given as to the rates of peroxidation of diethyl ether and di‐isopropyl ether under normal laboratory conditions of storage, both with and without inhibitors. Di‐isopropyl ether peroxidizes in daylight at least twice as rapidly, and in the dark several times as rapidly, as diethyl ether. By storing di‐isopropyl ether over 20% caustic soda the ether layer can be maintained almost free from peroxide. Anti‐oxidants effectively protect di‐isopropyl ether for limited periods. Diethyl ether can be protected from peroxidation by storage in presence of iron, and can be largely protected merely by storage in the dark.

It is proposed in this paper to review briefly the more recent literature dealing with the peroxidation and avoidance of peroxidation of diethyl and di‐isopropyl ethers and to record our own observations under both these heads.
A thermostat control unit
Authors: Vodden H. A.
Published: July 2007

A sensitive electronic thermostat control unit is described in which a thermistor is used as the sensing element. The output from the thermistor bridge network, after amplification, provides grid potential amplitude control of the current in a gas‐filled triode, the anode circuit of which contains the heating element. The unit is of the proportionate control type, and it can readily be adjusted to provide temperature control to within 0·025°C. at temperatures up to 120°c.
Stirred vessel cultures of rat brain cells aggregates: Characterization of major metabolic pathways and cell population dynamics
Authors: Santos Sónia Sá , Leite Sofia B. , Sonnewald Ursula , Carrondo Manuel J.T. , Alves Paula M.
Published: July 2007

We report a study on neural metabolism of long‐term three‐dimensional cultures of rat embryonic brain cells in stirred vessels. Our experimental setup was optimized to keep viable aggregate cultures with neuronal maintenance for up to 44 days. Results show that aggregate size and shape could be hydrodynamically controlled depending on the impeller design, avoiding necrotic centers or significant losses in cell viability. Aggregates were composed mainly of neurons until day 16, whereas an effective growth of the glial population was observed after day 21. Cell metabolic status was evaluated by quantification of several metabolites in the culture medium; amino acid metabolism was used as a marker of metabolic interrelationships between neural cell types. Furthermore, 13C‐NMR spectroscopy was used on day 31 to explore specific metabolic pathways: incubation with [1‐13C]glucose for 45 hr produced an increase in label incorporation in extracellular alanine, lactate, and glutamine, reflecting mainly astrocytic metabolism. The contribution of anaplerotic vs. oxidative pathways for glutamine synthesis was determined: a 92% reduction in the pyruvate carboxylase flux during the first 41 hr of incubation suggested a decrease in the need for replacing tricarboxylic acid cycle intermediates. We believe that our data corroborate the aggregating cultures as an attractive system to analyze brain cell metabolism being a valuable tool to model metabolic fluxes for in vitro brain diseases. © 2007 Wiley‐Liss, Inc.
Cellular Zn2+ chelators cause “dying‐back” neurite degeneration associated with energy impairment
Authors: Yang Yi , Kawataki Taku , Fukui Koji , Koike Tatsuro
Published: July 2007

Most cellular zinc is tightly associated with metalloproteins and other Zn2+‐dependent proteins, which along with cellular Zn2+ compartments may coordinately regulate cytoplasmic free Zn2+ levels in the picomolar range. Moreover, Zn2+‐containing endosomes or protein complexes appear to move along axons or dendrites, suggesting a dynamic mechanism for trafficking, exchanging, or scavenging Zn2+ and/or Zn2+ protein complexes in neurons. It is therefore interesting to examine whether cellular Zn2+ levels might alter neurite integrity and dynamics. Here we show that membrane‐permeable zinc chelators, including 1,10‐phenanthroline, N,N,N′,N′‐tetrakis‐(2‐pyridylmethyl)‐ethylenediamine (TPEN), and zinquin, selectively elicit axon and dendrite degeneration but leave the cell body intact in sympathetic neurons. The process begins distally and then moves retrogradely, with a distinct “dying‐back” pattern. An inactive isomer of 1,10‐phenanthroline failed to cause neuite degeneration, and these chelators mediated their effects by selectively chelating Zn2+, but not other metals. Moreover, neurite degeneration was associated with a decrease in neuritic ATP levels and was caused by energy failure, because an exogenous supply of nicotinamide adenine dinucleotide (NAD) or its precursor nicotinamide suppressed the degeneration by delaying axonal ATP reduction caused by Zn2+ depletion. Blockage of autophagy by 3‐methyladenine provided partial protection against degeneration of terminal axons or dendrites; there was, however, no obvious alteration in that of medial portions. Collectively, our results show that cellular Zn2+ depletion induces a “dying‐back” degeneration characterized by an NAD‐ and autophagy‐dependent process, independently of neurite elongation dynamics. © 2007 Wiley‐Liss, Inc.
Separation and quantification of 9‐(alkylthio)acridines by capillary micellar electrokinetic chromatography and capillary liquid chromatography
Authors: Nejmanová Jana , Coufal Pavel , Bosáková Zuzana , Suchánková Jana , Tesarová Eva
Published: July 2007

Various thioacridine derivatives are potential chemotherapeutics against various diseases which are intensively synthesized, characterized, and investigated by many research groups. Efficient, fast, and reliable separation and quantification methods for their analysis are still to be developed. MEKC and capillary LC (CLC) were applied for the separation and quantification of five highly hydrophobic, weakly basic, and structurally similar 9‐(alkylthio)acridines. Since the common anionic and cationic surfactants failed to separate the strongly hydrophobic thioacridines by MEKC, sodium cholate was used in an alkaline BGE and successfully employed for their fast separation. In CLC, the weakly basic nature of the thioacridines necessitated use of LiChrosorb RP‐select B sorbent as the stationary phase, which combined with a very simple mobile phase methanol/water yielded an efficient chromatographic separation system. Both, the MEKC and CLC optimized separation methods were then applied to quantify the thioacridines within a concentration range of 1.0×10–5–1.0×10–3 mol/L and the obtained experimental results were critically compared. In practical terms, the MEKC analytical method can quantify the analytes much faster but with a lower reliability while the CLC method performs slower analysis with a higher repeatability of the experimental results.
Simultaneous determination of four active constituents in the roots of Scrophularia buergeriana by HPLC‐DAD and LC‐ESI‐MS
Authors: Lee Mi Kyeong , Choi Ok‐Gyung , Park Jin‐Ho , Cho Hi‐Jae , Ahn Mi‐Jeong , Kim Seung Hyun , Kim Young Choong , Sung Sang Hyun
Published: July 2007

The chemical profile of four main bioactive constituents including harpagoside (HS), 8‐O‐(E‐p‐methoxycinnamoyl)harpagide (HG), E‐cinnamic acid (CA), and E‐p‐methoxycinnamic acid (MCA), in the extract of Scrophularia buergeriana was studied using HPLC‐diode array detector‐electrospray‐MS (HPLC‐DAD‐ESI‐MS). The HPLC‐DAD conditions were optimized for the simultaneous analysis of these four compounds. This method was validated in terms of specificity, linearity (r2 >0.9998), precision (< 2.0% RSD), and recoveries (94.4–115.1%). The LOD of these compounds were ranged from 5.9 to 37.8 ng. In addition, the main compounds in S. buergeriana and S. ningpoensis were quantified using this validated method, which resulted in significant difference in the contents of these compounds between the species.
Development of an HPLC method for the monitoring of tricyclic antidepressants in biofluids
Authors: Samanidou Victoria F. , Nika Maria K. , Papadoyannis Ioannis N.
Published: July 2007

A simple, rapid and sensitive HPLC method was developed and validated for the determination of four tricyclic antidepressants (TCAs): amitriptyline, doxepin, clomipramine (CLO) and imipramine, in pharmaceutical formulations and biological fluids. A Kromasil C8 analytical column (250×4 mm, 5 μm) was used for the separation, with a mobile phase consisting of 0.05 M CH3COONH4 and CH3CN (45:55 v/v) delivered at 1.5 mL/min isocratically. Quantification was performed at 238 nm, with bromazepam (1.5 ng/μL) as the internal standard. The determination of TCAs in blood plasma was performed after protein precipitation. Urine analysis was performed by means of SPE using Lichrolut RP‐18 Merck cartridges providing high absolute recoveries (> 94%). Direct analysis of urine was also performed after two‐fold dilution. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between‐day precision (n = 5) revealed RSD <13%. Recoveries from biological samples ranged from 91.0 to 114.0%. The absolute detection limit of the method was calculated as 0.1–0.6 ng in blood plasma and 0.2–0.5 ng in extracted urine or 0.4–0.7 in diluted urine. The method was applied to real samples of plasma from a patient under CLO treatment.
Cad compatible accurate models of microwave passive lumped elements for mmic applications
Authors: Sadhir Virender K. , Bahl Inder J. , Willems David A.
Published: July 2007

This article presents accurate measurement‐based models derived from measured S‐parameters of passive circuit elements which include inductors, thin‐film resistors, interdigital and MIM capacitors, via holes, and airbridges for use in the computer‐aided design of monolithic microwave integrated circuits (MMICs). The thru‐reflect‐line (TRL) calibration method is employed to accurately measure the S‐parameters of the passive elements. Some of the models are scalable for different substrate thicknesses and substrate dielectric constant values as they are based on microstrip line theory. © 1994 John Wiley & Sons, Inc.
Managing the Multi‐protocol, Multi‐media Network
Authors: Restivo Ken
Published: July 2007

The Light Watch network management system combines advanced speed, functionality with an easy‐to‐use graphical interface.
Isolating Problems in a Token‐Ring Network
Authors: Nilausen Jesper
Published: July 2007

The basis for a very efficient network management implementation is found in the way the Token‐Ring protocol works. Management reporting procedures are integrated into the Token‐Ring data flow by being part of the idle running traffic in every ring.
So Many MIBs!
Authors: Koren Debby
Published: July 2007

The proliferation of MIBs can provide a wealth of information to the network manager, but to process this information requires some investment in understanding the MIBs supported by the device being managed.
Constructing The Non‐stop, Self‐healing T1 Network
Authors: Wilkinson Harvey
Published: July 2007

Automatic protection switching that is integrated into a sensible backup scheme will keep T1 lines functioning even in the face of disaster.
DECnet/OSI—Part 3: DECnet/OSI Network Management
Authors: Snellen David
Published: July 2007

In the previous articles on DECnet/OSI the focus has been on the technical aspects of Digital's implementation, alias Advantage Networks. The openness of Advantage Networks is both good and bad. It's good because you have the freedom to mix and match network devices to fit your specific needs. It's bad because a heterogeneous network environment will be very difficult to manage. In this article the discussion is on Digital's concept of managing a DECnet/OSI network management.
Token Ring Network Management
Authors: Nilausen Jesper
Published: July 2007

This article on Token Ring network management describes general aspects of this important area and gives a brief introduction to the various disciplines, which will be covered in more detail in following articles.
CSMA/CD Network Problem Threshold
Authors: Gejji Raghvendra R.
Published: July 2007

CSMA/CD network transmission errors such as collisions, CRC errors, misalignment, etc. are statistical in nature. Although errors can vary randomly, a high level of errors does indicate specific network problems (e.g. equipment failure). This paper examines the random nature of collisions theoretically as well as from actual statistics, and establishes a threshold above which a network problem is indicated with a high probability.
LAN standards and policies: A How‐to guide
Authors: Barrett Katherine Epes
Published: July 2007

This article is a ‘how‐to’ guide for developing LAN standards and policies. It discusses what LAN standards and policies are; when they should be used; how to develop them; and, most importantly, how to implement and manage them without incurring the wrath and rebellion of the user.
Token ring network management: Problem management
Authors: Nilausen Jesper
Published: July 2007

Following the tutorial ‘Token Ring Network Management’ article in the previous issue of the International Journal of Network Management, this article takes us through some more detailed Problem Management scenarios.
Planning networked systems for total quality management
Authors: Choudhury A.
Published: July 2007

This paper deals with issues pertinent to the design of network technology platforms (NT) for supporting total quality management (TQM). We focus on two major issues in the design of such systems: the demand side and the supply side of networked systems for quality management.
Remote‐control Software Aids Help Desk Problem Resolution
Authors: Muller Nathan J.
Published: July 2007

The in‐house help desk can prevent new computer users who may not have basic computer skills from damaging files and possibly tying up network resources. Aside from handling trouble calls from users, help desks can provide such services as order and delivery tracking, asset and inventory tracking, preventive maintenance, and vendor performance monitoring.
Internet's SNMP and ISO's CMIP Protocols for Network Management
Authors: Jones Katherine
Published: July 2007

The scope of network management has both expanded and been clarified in the recent past. Here we will look at the underlying protocols which aid in the delivery of network management today.
A Generic Management System for Heterogeneous Networks
Authors: Bhushan Bharat , Patel Ahmed
Published: July 2007

This paper summarizes the key requirements for the system, presents an object‐oriented model of the heterogeneous networks, and gives a brief description of the main functional parts of the system. The model discussed in this paper consists of object classes representing protocol layers such as TCP/IP layers or the data link layer of the X.25 protocol.
I2NMA: An intelligent integrated network management architecture
Authors: Gaïti Dominique
Published: July 2007

This paper is devoted to the presentation of a new intelligent architecture adapted to network management.
Beyond network management: Planning for disaster recovery
Authors: Jones Katherine
Published: July 2007

Network administrators have enough to do in the day‐to‐day management of LANs and WANs without worrying about what might happen in the event of a catastrophe. A wide range of problem events can occur which can knock out a network, so a disaster recovery plan is an important consideration.
The Evolution of a Network—A Case Study of Network Development at John Wiley & Sons
Authors: Meyers Warren S.
Published: July 2007

This case study explores the impact of network growth and development on John Wiley and Sons, a corporation that is highly dependent upon the relationships between information needs, new technologies, and evolving business requirements and relationships.
Solar‐powered air conditioner
Authors: Takeoka A. , Fukuda Y. , Suzuki M. , Hasunuma M. , Sakoguchi E. , Tokizaki H. , Kouzuma S. , Waki M. , Ohnishi M. , Nakano S. , Kuwano Y.
Published: July 2007

We have successfully developed and industrialized a solar‐powered air conditioner that operates through a combination of photovoltaic (PV) arrays and commercial power supplies. In order to achieve the most efficient operation possible from a one‐horsepower inverter‐type household air conditioner, we selected a PV array output of 540 W under standard test conditions, based on single‐day power use patterns for air conditioners as well as on solar cell output patterns.

When using a 540‐W PV array, we have shown that the system can supply at least 90% of the power consumed by an air conditioner during peak power periods in summer. We have confirmed that on average the power generated by the PV array can satisfy at least 50% of the power consumed by an air conditioner in summer. We also confirmed that the system functions according to system design specifications. There is little doubt that the introduction and widespread use of this system will play an important role in reducing peak power energy requirements in summer.
Metastability of phosphorus and boron in hydrogenated amorphous silicon
Authors: Nebel C. E. , Street R. A. , Johnson N. M. , Jackson W. B.
Published: July 2007

Thermodynamic equilibration kinetics of phosphorus‐ and boron‐doped hydrogenated amorphous silicon (a‐Si:H) are explored using dark conductivity measurements. the equilibration kinetics of phorphorus‐ and boron‐doped a‐Si:H are different and there is a strong dependence on the deposition temperature (Ts). Small variations in temperature of the semiconductor cause variations in active dopant concentration, which affects the conductivity. the transformation of phorphorus into the electronically active phase (activation) follows a stretched exponential time dependence with a temperature‐independent dispersion parameter, β, of 0.85, whereas the transformation into the electronically passive bonding configuration (passivation) is also a stretched exponential but with β ⩽ 0.8. the kinetics of boron metastability are similarly a stretched exponential, but with equal β values for activation and passivation. the time constant, τ, to achieve equilibrium for both transformations is thermally activated with energies Eact ∽ 1.1 eV for phosphorus and boron. an increase in Ts leads to an increase of Eact. the data are discussed and interpreted based on the hydrogen migration model.
Control of particulate and gas emissions in photovoltaic module manufacture
Authors: Fthenakis V. M. , Moskowitz P. D.
Published: July 2007

Emissions of toxic gases and particulates from photovoltaic module R&D and manufacturing facilities may need treatment to meet current or anticipated regulations. In this study currently available pollution‐control options (e.g. filters, scrubbers, adsorption columns, combustion devices) are reviewed for their suitability to treat emissions (e.g. HCl, HF, Cl2, H2Se, SiH2, SiH2Cl2, AsH3, PH3, Cd and As compounds) from photovoltaic cell laboratories and production facilities. For small emission flow rates (e.g. > 100 l min−−1) and small to moderate particulate loads (e.g. <2 mg l−−1), on‐line filters can economically collect fumes and other particulates generated in the deposition chambers, whereas adsorption columns can very effectively treat toxic hydrates (e.g. AsH3, PH3, H2Se) at concentrations up to 1% (up to 10% for very small flow rates, e.g. <11 min−−1). For large emission flow rates, (e.g. > 100 1 min−−1), very low concentrations of hydrates can still be treated effectively with adsorption. Combined control of particulates and hydrates can be achieved by a bag‐house followed by a multistage scrubber; when the concentration of hydrates is relatively high, a thermal oxidation unit should precede the bag‐house scrubber for effective control. Finally, multicomponent mixtures can be treated either by wet scrubbing or combustion, depending on the mixture composition.
Solar cell efficiency tables (version 6)
Authors: Green Martin A. , Emery Keith , Bücher Klaus , King David L.
Published: July 2007

Updated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and several new entries since January 1995 are briefly described.
The dynamics of economic growth and political instability in developing countries
Authors: Saeed Khalid
Published: July 2007

Accelerating the rate of economic growth in developing countries has been an important aim of almost all development policies implemented over the past three decades. Experience has shown that such growth is often not sustainable and is likely to be interrupted by violent political changes. This paper attempts to identify the organizational factors that limit economic growth and create conditions conducive to the outbreak of political violence. A system dynamics model of the sociopolitical organization of a developing country is presented, and the model's behavior is studied using computer simulation.
Coupling DYNAMO and optimization software
Authors: Gustafsson Leif , Wiechowski Miroslaw
Published: July 2007

Notes and Insights is a forum for discussion and debate about current issues in the philosophy and application of the system dynamics approach, and a marketplace for the exchange of information about current research, policy issues, and teaching experiences. Manuscripts treating material particularly suited to presentation in short form (less than 2,000 words) should be sent to Erich Zahn, Betriebswirtschaftliches Institut, Universität Stuttgart, Herdweg 23, D‐7000 Stuttgart 1, West Germany.
Migratory dynamics of interacting subpopulations: Regular and chaotic behavior
Authors: Reiner Rolf , Munz Martin , Weidlich Wolfgang
Published: July 2007

We demonstrate that different kinds of dynamic behavior may occur in a general migration system. The deterministic nonlinear coupled mean value equations are introduced. The intergroup and intragroup interactions of the subpopulations determine the dynamics of the system. First, the route to chaotic motion in the case of two subpopulations migrating between three regions is briefly presented. In the special case of three interacting sub‐populations migrating between three regions, we then show in detail that all kinds of attractors (fixed points, limit cycles, and strange attractors) exist. Characteristics of the motion, namely the Fourier spectrum, Lyapunov exponents, and the fractal dimension of the attractors, are analyzed. Finally, we discuss the relevance of the results for real migration systems.
Aging, contraction, and cohesion in a religious order: A policy analysis
Authors: Gaynor Alan K. , Morrow Jean , Georgiou Stelios N.
Published: July 2007

This article is a study of problems of contraction and cohesion in the Order of the Servants of Mary. Focusing on the history of the Order since the Second Vatican Council (1962‐1965), it seeks to uncover the dynamics that underlie these problems and to recommend broad directions for future policy. The logical level of the policy recommendations conforms with that of the analysis, which concentrates on a few highly aggregated driving forces.
The dynamics of managing a life insurance company
Authors: Doman Andrew , Glucksman Maurice , Mass Nathaniel , Sasportes Michel
Published: July 2007

This article reports the findings of an internal McKinsey research and development project designed to test the value of applying system dynamics thinking to the life insurance industry. The aim was to understand better how management decisions and actions can affect the success or failure of a typical direct sales life company. The study compared the evolution over 20 years of two companies, which in the interests of confidentiality, we will refer to as “Tortoise Life” and “Hare Life”. Starting out in 1975 from virtually identical competitive positions, Tortoise Life has become one of the U.K.'s most successful life companies, while Hare Life had to be rescued from near insolvency in 1989. We found system dynamics a powerful means of identifying which managerial actions had accounted for the extraordinary divergence of the two companies. The lessons learned include many counterintuitive insights that have relevance for any life‐company manager. Through simulation we were able to isolate which management actions made the difference to long‐term performance. In particular, we show how attempts to exceed the maximum sustainable growth rate specific to any individual company can lock it into a slow but relentless spiral of decline, from which there is little hope of escape. This growth ceiling can be quantified and we also identify a number of long range early warning signs. Consequently, we believe that our conclusions are likely to change the way life companies are managed in the future.
Esophageal obstruction—prenatal detection rate and outcome
Authors: Brantberg A. , Blaas H‐G. K. , Haugen S. E. , Eik‐Nes S. H.
Published: July 2007

Objective

Prenatal diagnosis of esophageal obstruction is believed to improve the outcome for the affected newborn. However, the prenatal detection rate is only 10–40%, the diagnosis is usually not made before the third trimester and the false‐positive rate has been high. This study investigated the prenatal detection rate and time of prenatal diagnosis at our center and its influence on outcome. In addition, incidence, detection rate and accuracy of the diagnosis in a large non‐selected population were determined.

Methods

All cases diagnosed pre‐ or postnatally with esophageal obstruction and examined prenatally by ultrasound at the National Center for Fetal Medicine in Norway during 1987–2004 were evaluated.

Results

Of 48 cases with esophageal obstruction, 21 (44%) were diagnosed prenatally (median, 32 + 0 weeks). All 21 had a small or empty stomach, 20/21 (95%) had polyhydramnios and 9/21 (43%) had a visible esophageal pouch. Associated anomalies were present in 38/48 cases (79%). The karyotype was abnormal in 11/48 cases (23%). Ten (21%) pregnancies with lethal fetal conditions were terminated. Two fetuses died in utero. Ten infants with associated anomalies died within 3 months after birth. The 26/48 (54%) survivors included 16/21 cases with a prenatal diagnosis of esophageal obstruction and 9/10 cases with isolated esophageal obstruction.

Conclusions

The clinical signs of polyhydramnios were the most important factors for prenatal detection of esophageal obstruction. Consequently, the time of diagnosis was late and the detection rate was low (44%). An increased awareness of the possibility of esophageal obstruction, leading to targeted examinations whenever the suspicion is raised during pregnancy, might improve the prenatal detection rate and thereby provide a possibility to improve the outcome. Of the cases with isolated esophageal obstruction, 90% survived, irrespective of prenatal diagnosis. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Sinonasal hybrid tumour involving the anterior skull base
Authors: Mazita A , Gendeh B S , Zainal A I
Published: July 2007

Objective:

We report a rare case of sinonasal hybrid tumour within an inverted papilloma.

Method:

The patient's case history and course of management are presented. The relevant medical literature are reviewed and discussed.

Results:

A 60-year-old man presented with unilateral nasal obstruction associated with anosmia. An ENT examination revealed a unilateral, left nasal mass. A provisional diagnosis of inverted papilloma was made. The patient underwent a transnasal endoscopic excision of the tumour, which was unfortunately complicated by a cerebrospinal fluid leak. Further treatment of this patient is described. We highlight the features of associated malignancy in inverted papilloma, and the importance of thorough histopathological examination of tissue specimens.

Conclusion:

Treatment of inverted papilloma with limited involvement of the skull base can be successfully achieved by endoscopic excision. A high index of clinical suspicion, together with meticulous histopathological examination, will enable diagnosis of associated malignancy. This will ensure that appropriate adjuvant treatment is given, resulting in a good clinical outcome.
Nonlinear elliptic problems on singularly perturbed domains
Authors: Byeon Jaeyoung
Published: July 2007

We consider how the shape of a domain affects the number of positive solutions of a nonlinear elliptic problem. In fact, we show that if a bounded domain Ω is sufficiently close to a union of disjoint bounded domains Ω1,…, Ωm, the number of positive solutions of a nonlinear elliptic problem on Ω is at least 2m −1.
A biharmonic problem with constraint involving critical Sobolev exponent
Authors: Guedda M. , Hadiji R. , Picard C.
Published: July 2007

We are concerned with the following minimization problems,

where Ω ⊂ RN, N > 4, is a smooth bounded domain, qc = 2N/(N − 4), ϕ ∈ C(Ω) ∩ Lqc(Ω) and . We show that, for ϕ ≢ 0, each infimum is achieved. Under suitable conditions on ϕ, we establish the following gap phenomenon,

for q ≤ qc.

Moreover, we study the limit behaviour of the minimizers, as q goes to qc, in the case ϕ ∈ H(Ω).
A remark on a paper by Evans and Harris on the point spectra of Dirac operators
Authors: Schmidt Karl Michael
Published: July 2007

This paper presents a sufficient condition for a one-dimensional Dirac operator with a potential tending to infinity at infinity to have no eigenvalues. It also provides a quick proof (and suggests variations) of a related criterion given by Evans and Harris.
Decay spectrum and decay subspace of normal operators
Authors: Antoniou I. , Shkarin S. A.
Published: July 2007

Let A be a self-adjoint operator on a Hilbert space. It is well known that A admits a unique decomposition into a direct sum of three self-adjoint operators Ap, Aac and Asc such that there exists an orthonormal basis of eigenvectors for the operator Ap, the operator Aac has purely absolutely continuous spectrum and the operator Asc has purely singular continuous spectrum. We show the existence of a natural further decomposition of the singular continuous component Asc into a direct sum of two self-adjoint operators and . The corresponding subspaces and spectra are called decaying and purely non-decaying singular subspaces and spectra. Similar decompositions are also shown for unitary operators and for general normal operators.
On an integral transform associated with the regular Dirac operator
Authors: García A. G. , Hernández-Medina M. A.
Published: July 2007

In this paper we deal with a linear integral transform, defined on a vectorial L2-space, whose kernel arises from a one-dimensional system of Dirac operators. Unlike the regular Sturm–Liouville transform, which is associated with a regular Sturm–Liouville problem, the range of this transform is a whole Paley–Wiener space. As a consequence, some results for the Paley–Wiener space are derived; in particular, the sampling formula associated with a regular Dirac operator. Finally, we obtain an inversion formula by means of a continuous measure for suitable Sobolev spaces in the initial L2-space.
Admissible Lp norms for local existence and for continuation in semilinear parabolic systems are not the same
Authors: Quittner Pavol , Souplet Philippe
Published: July 2007

We say that a Banach space E is a continuation space for a given parabolic problem if the E-norm of any non-global solution has to become unbounded. We will prove that for large classes of parabolic systems of two equations, the space E = Lr1 × Lr2 can be a continuation space even though the problem is not locally well posed in E. This stands in contrast with classical results for analogous scalar equations.
Hardy spaces on ZN
Authors: Boza Santiago , Carro María J.
Published: July 2007

The work of Coifman and Weiss concerning Hardy spaces on spaces of homogeneous type gives, as a particular case, a definition of Hp(ZN) in terms of an atomic decomposition.

Other characterizations of these spaces have been studied by other authors, but it was an open question to see if they can be defined, as it happens in the classical case, in terms of a maximal function or via the discrete Riesz transforms.

In this paper, we give a positive answer to this question.
On subhereditary radicals and reduced rings
Authors: Beidar K. I. , Ke W.-F. , Puczyłowski E. R.
Published: July 2007

We answer some open problems on subhereditary radicals of associative rings. In particular, we show that the Brown–McCoy radical is not subhereditary and that every left or right subhereditary and left or right stable radical satisfies all these properties. The latter of these results concerns, in fact, the question whether some classes of reduced rings are closed under one-sided essential extensions. We characterize several such classes.