bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular architecture of poly[(R,S)‐3‐hydroxybutyrate‐co‐6‐hydroxyhexanoate] and poly[(R,S)‐3‐hydroxybutyrate‐co‐(R,S)‐2‐hydroxyhexanoate] oligomers investigated by electrospray ionization ion‐trap multistage mass spectrometry
Authors: Adamus Grażyna , Montaudo Maurizio S. , Montaudo Giorgio , Kowalczuk Marek
Published: May 2004

A series of aliphatic copolyesters was obtained from (R,S)‐β‐butyrolactone and two isomeric hydroxy acids, 6‐hydroxyhexanoic and (R,S)‐2‐hydroxyhexanoic acids. The reactions were conducted in bulk without catalyst. Electrospray ionization tandem mass spectrometry (ESI‐MSn) was used for molecular characterization of these copolyester oligomers. The mass spectra of the copolyesters studied have enabled identification of their molecular structures including chemical nature of the end groups (hydroxyl and carboxylate). The compositions of the oligocopolyesters and their sequence distributions were determined based on measurement of the relative intensities of the individual oligocopolyester peaks in the ESI mass spectra. The mass spectra (MS1) provided information on composition and sequence distribution, and small deviations from Bernoulli statistics were detected. The arrangement of co‐monomer structural units along the oligopolyester chains was verified by MS/MS experiments and investigation of the fragmentation pathways. Copyright © 2004 John Wiley & Sons, Ltd.
Incongruent dissolution of chromite in lithium tetraborate flux
Authors: Merkle Roland K. W. , Loubser Maggi , Gräser Peter P. H.
Published: May 2004

During lithium tetraborate fluxing, chromite undergoes incongruent dissolution, in which high proportions of aluminium, magnesium and titanium are dissolved in the flux while some iron remains behind in a residual chromium‐rich phase. Increasing the time and flux/sample ratio improve the dissolution of chromite. Errors in XRF analysis due to incomplete dissolution of chromite in lithium tetraborate flux will have the largest effects for chromium and lesser, although still serious, effects for iron. Copyright © 2004 John Wiley & Sons, Ltd.
Zur Kristallstruktur von Ba3Al2F12
Authors: Kaiser V. , Babel D.
Published: May 2004

Bei der Darstellung von BaMnAlF7 erhielten wir als Nebenprodukt Einkristalle von Ba3Al2F12 (a = 1020, 3(2), b = 988, 5(1), c = 952, 2(1) pm, Raumgruppe Pnnm, Z = 4). Die erneute Verfeinerung bestätigte die schon bekannte Struktur, lieferte aber verbesserte Ergebnisse (R1′ = 0, 028 bzw. wR2 = 0, 06 für 1908 bzw. 2717 Reflexe), die hinsichtlich der Abstandsverhältnisse im tetrameren Anion [Al4F20]8— (Mittelwert Al—F: 180, 1 pm) gedeutet werden. Der Aufbau des kationischen Gerüsts [Ba3F2]4+ wird diskutiert.
Multiply Borylated Arenes: X‐ray Crystal Structure Analyses and Quantum Chemical Calculations
Authors: Haberecht Monika C. , Heilmann Julia B. , Haghiri Alireza , Bolte Michael , Bats Jan W. , Lerner Hans‐Wolfram , Holthausen Max C. , Wagner Matthias
Published: May 2004

Optimised synthesis procedures and results of X‐ray single crystal structure analyses for 4‐(dibromoboryl)toluene, 1, 3‐bis(dibromoboryl)benzene, 1, 4‐bis(dibromoboryl)benzene, and 1, 3, 5‐tris(dibromoboryl)benzene are reported. These compounds have also been studied by Hartree‐Fock (HF), density functional theory (DFT), and Mßller‐Plesset second‐order perturbation (MP2) methods in combination with the polarized double‐ζ valence (SVP) and polarized triple‐ζ valence (TZVP) basis sets of Ahlrichs and coworkers. A comparison of the quantum chemical results for optimised geometries and computed NMR chemical shifts with experiment is presented to test the quality of the various methods for this class of compounds. All DFT methods tested yield optimised geometries within the experimental error bars of 3σ for bond lengths, whereas larger deviations among the methods are observed for computed NMR chemical shifts. This calibration recommends the B3LYP/SVP combination as a reliable and computationally efficient level of theory to assess the structures and absolute and relative 1H‐, 13C‐ and 11B NMR shift values of borylated aromatic compounds in future investigations.
Preparation and Crystal Structure Analyses of Compounds in the Systems HgO/MXO4/H2O (M = Co, Zn, Cd; X = S, Se)
Authors: Weil Matthias
Published: May 2004

During phase formation experiments under hydrothermal conditions (250 °C, 5d) in the systems HgO/MXO4/H2O (M = Co, Zn, Cd; X = S, Se), single crystals of the mercuric compounds (CdSO4)2(HgO)2H2O (I), (CdSeO4)2(HgO)2H2O (II), (CdSeO4)Hg(OH)2 (III), (CoSO4)2(HgO)2H2O (IV), (ZnSO4)2(HgO)2H2O (V), (ZnSeO4)2(HgO)2H2O (VI), and the mixed‐valent (ZnSeIVO3)(ZnSeVIO4)HgI2(OH)2 (VII) were obtained. The crystal structure determinations from X‐ray diffraction data revealed four unique structure types for these compounds. I and II crystallise isotypically in space group P2/n (a ≈ 7.85, b ≈ 6.28, c ≈ 10.5Å, β ≈ 102°), compound III crystallises in space group C2/m (a = 10.540(2), b = 9.0120(8), c = 6.1330(12)Å, β = 100.45(3)°), and the isotypic compounds IV, V and VI crystallise in space group Pbcm (a ≈ 6.15, b ≈ 11.3, c ≈ 13.1Å). Common with these three structure types are distorted octahedral [MO6] and tetrahedral XO4 building units which are organised in a layered assembly. Within the layers H bonding of OH groups or H2O molecules of the [MO6] octahedra leads to an additional stabilisation. Adjacent layers are separated by mercury atoms which are linearly bonded to two O atoms at short distances, forming either interconnecting [O‐Hg‐O] units which are part of [O‐Hg‐O]∞ zig‐zag chains, or single [HO‐Hg‐OH] units (realised in compound III). VII is the only compound with mercury in oxidation state +1. It crystallises in space group C2/m (a = 17.342(3), b = 6.1939(10), c = 4.4713(8)Å, β = 90.154(3)°) and is made up of Hg22+ dumbbells, [ZnO4(OH)2] octahedra, and statistically distributed SeVIO4 and SeIVO3 groups as the main building units.
Synthesen und Kristallstrukturen von Cu‐ und Ag‐Komplexen mit Dithiophosphinat‐ und Trithiophosphonat‐Liganden
Authors: Fenske Dieter , Rothenberger Alexander , Shafaei Fallah Maryam
Published: May 2004

Durch Reaktionen von CuI‐ und AgI‐Salzen mit Diphenyldithiophosphinsäuretrimethylsilylester in Gegenwart von tertiären Phosphanen erhält man die Komplexe [Cu(μ‐S)SPPh2(PR3)]2 (R = Me 1a, iPr 1b), [Ag(μ‐S)SPPh2(PnPr3)]2 (2), [Ag(S2PPh2)(PEt3)]2 (3) und [Cu8(μ8‐S)(S2PPh2)6] (4). Bei Verwendung von Phenyltrithiophosphonsäuretrimethylsilylester wird die Käfigverbindung [(PhPS3)2Cu4(PMe3)5] (5) gebildet. Die Verbindungen wurden mit Hilfe der Röntgenstrukturanalyse charakterisiert.
Causes and consequences of unwanted pregnancy from Asian women's perspectives
Authors: Kabir Sandra M.
Published: May 2004

Shortcomings of contraceptives and of family planning delivery systems are major reasons for unwanted pregnancy and unsafe abortion in Third World countries. Family planning and health programs should provide empathetic counseling for contraceptive choices and pregnancy termination, adjust management systems and procedures to facilitate women's access to services and information, and offer comprehensive services to meet their multiple reproductive health needs.
The significance and scope of reproductive tract infections among Third World women
Authors: Wasserheit Judith N.
Published: May 2004

Due to biomedical, behavioral and societal factors, reproductive tract infections are widespread in the Third World. Without early diagnosis and accurate therapy, their complications severely compromise women's health, fertility and productivity; infant health and survival; and the effectiveness of family planning programs. Clinicians and public health planners can address these treatable syndromes through research and services in socially acceptable settings including family planning, prenatal and MCH clinics. Specific approaches are discussed.
Portrait of an instrument-maker: Wenceslaus Hollar's engraving of Elias Allen
Authors: HIGTON HESTER
Published: May 2004

Among the many engravings of landscapes, buildings, portraits and other illustrations produced by the seventeenth-century artist Wenceslaus Hollar, there are a small number of images of contemporary men of science. Of particular interest is the portrait of the instrument-maker Elias Allen, both because portraits of men of his social status were extremely uncommon at this time, and also because the cluttered mass of instruments shown in the image presents a picture wholly unlike other portraits of the period. The first part of this paper explores the position of portraiture as inherently linked to nobility, and seeks to present an explanation as to why the original oil painting of Allen (made by Hendrik van der Borcht and no longer extant) might have been made. The second part looks at the image itself, and discusses possible reasons for Hollar's production of the engraving some twenty years after the original.
Poverty alleviation and biodiversity conservation: a South African perspective
Authors: Kepe Thembela , Saruchera Munyaradzi , Whande Webster
Published: May 2004

The relationship between poverty alleviation and biodiversity conservation has been the subject of intense debate amongst academics and development practitioners for several decades, yet consensus on how to reconcile these two disparate goals is far from being reached.
The debate is often characterized by polemics
between different camps, particularly on which strategy
works best. Without trivializing the quality of scholarship
within this debate, we argue that it is delineated by
two major factors. Firstly, residents of rich countries and
residents of poor countries are often assumed to be
in opposition on this matter. On the one hand, some
analysts tend to blame the loss of biodiversity on alleged
excessive use of natural resources by residents of poor
countries, while on the other hand there are those who
blame residents of rich countries for alleged unsustainable
livelihood strategies. Secondly, the debate on the
contested relationship between biodiversity conservation
and poverty alleviation is often characterized by a
tussle between proponents of biodiversity conservation
and human rights/anti-poverty activists.
The defence of conservation is not an attack on the poor
Authors: Sanderson Steven , Redford Kent
Published: May 2004

The relationship between poverty alleviation and biodiversity conservation continues to vex conservationists and social analysts alike.
The three responses to our
earlier Guest Editorial (Sanderson & Redford, 2003) help
refine the arguments and shape the angles from which
to approach the debate, but neither the editorial nor the
responses satisfy entirely. What missing pieces must be
found and fitted to the puzzle?
Range contraction in the pampas meadowlark Sturnella defilippii in the southern pampas grasslands of Argentina
Authors: Gabelli Fabián M. , Fernández Gustavo J. , Ferretti Valentina , Posse Gabriela , Coconier Eugenio , Gavieiro Hernán J. , Llambías Paulo E. , Peláez Pablo I. , Vallés María L. , Tubaro Pablo L.
Published: May 2004

The Vulnerable Pampas meadowlark Sturnella defilippii (Family Icteridae) is a Neotropical grassland bird that suffered a severe population reduction and range contraction during the 20th century. Formerly distributed across most of the pampas grasslands, it is now confined to the southern tip of its original range. There are small groups of wintering birds in southern Brazil, a small reproductive population in eastern Uruguay, and the main reproductive population occurs on the southern pampas grasslands of Argentina. In this paper we report the results of an extensive field survey of these southern pampas grasslands, carried out to estimate the pampas meadowlark's population size and to identify the factors potentially responsible for its range contraction. During the 1999 breeding season we surveyed a total of 296 sample locations (transects, randomly selected points, and sites checked for nesting site reoccupation). We found 66 reproductive groups of pampas meadowlarks. The minimum population size and extent of occurrence were estimated to be 28,000 individuals and 4,810 km2, respectively. This value represents a range contraction of c. 30% compared to that estimated in a study carried out between 1992 and 1996. Pampas meadowlarks reoccupied natural grassland sites for nesting that were used in previous breeding seasons when these sites remained undisturbed. Habitat transformation appears to be the main factor causing the range contraction of the pampas meadowlark. We suggest that long-term monitoring of this population and its preferred habitat, the natural grasslands, is required in order to ensure the conservation of this species.
On the verge of extinction: a survey of the mangrove finch Cactospiza heliobates and its habitat on the Galápagos Islands
Authors: Dvorak Michael , Vargas Hernán , Fessl Birgit , Tebbich Sabine
Published: May 2004

The Critically Endangered mangrove finch Cactospiza (=Camarhynchus) heliobates is now confined to Isabela Island in the Galápagos Islands and is exclusively found in mangrove forests. Formerly it occurred also on neighbouring Fernandina Island, but is apparently extinct there. The population size and ecology of the species was relatively unknown until 1994. We conducted surveys, habitat assessments and behavioural observations of the species between 1996 and 2000. Although Isabela Island has approximately 760 ha of mangrove forests, breeding was confirmed at only two sites, comprising 32 ha in total, on the north-western coast. Our estimate of the population in these two areas is 100 individuals. Additionally, 3–5 territories (which probably contained breeding individuals) were discovered on the south-eastern coast. A comparison of habitat parameters showed that tree height and amount of dead wood were significantly higher within than outside territories, and these are therefore likely to be important habitat components for this species. As considerable structural differences were detected between the two sites holding the main populations and all other mangrove stands on Isabela, it seems possible that the latter are sub-optimal habitat. We therefore conclude that one of the reasons for the very limited distribution of the species is habitat degradation caused by hitherto unknown factors.
Limits on an intrinsic dipole moment in Europa
Authors: Schilling N. , Khurana K. K. , Kivelson M. G.
Published: May 2004

Galileo magnetometer data acquired on four passes by Europa have been used to investigate whether a fixed permanent dipole moment is present in the interior of the moon in addition to the induced dipole moment previously identified. The data from several low‐altitude passes have been fitted to models of increasing complexity. The simplest models of the magnetic field fit the measurements to internal multipoles fixed to the satellite, first through lowest‐order dipole and subsequently through second‐order quadrupole. In these models the magnetic field of Jupiter supplemented by a uniform magnetic field that is allowed to change from pass to pass is used to describe the external field as a first‐order approximation. Superimposing an induced magnetic dipole moment that is driven by the time variation of the measured external magnetic field of Jupiter improves the fits and reduces the rms error that characterizes the difference between the model and the data. In more ambitious models the plasma currents in the vicinity of Europa are approximated as wire currents forming an Alfvén wing. The inductive response is found to be ∼97% of the theoretical maximum inductive response for a highly conducting sphere. The largest surface equatorial field caused by a fixed internal dipole moment is less than 25 nT. This should be compared with the magnitude of the induced field, which can be of order 100 nT. We thereby confirm the presence of an inductive response and conclude that the dipole coefficients of the constant intrinsic field contribute at most in a very minor way to the magnetic field.
Volcanic forcing improves Atmosphere‐Ocean Coupled General Circulation Model scaling performance
Authors: Vyushin D. , Zhidkov I. , Havlin S. , Bunde A. , Brenner S.
Published: May 2004

Recent Atmosphere‐Ocean Coupled General Circulation Model (AOGCM) simulations of the twentieth century climate, which account for anthropogenic and natural forcings, make it possible to study the origin of long‐term temperature correlations found in the observed records. We study ensemble experiments performed with the NCAR PCM for 10 different historical forced simulations, including no forcings, greenhouse gas, sulfate aerosol, ozone, solar, volcanic forcing and various combinations, such as natural, anthropogenic and all forcings. We compare the scaling exponents characterizing the long‐term correlations of the observed and simulated model data for 16 representative land stations and 16 sites in the Atlantic Ocean for these forcings. We find that inclusion of volcanic forcing in the AOGCM considerably improves the PCM scaling behavior. The simulations containing volcanic forcing are able to reproduce quite well the observed scaling exponents for the land with exponents around 0.65 independent of the station distance from the ocean. For the Atlantic Ocean, simulations with the volcanic forcing slightly underestimate the observed persistence exhibiting an average exponent 0.74 as compared to 0.85 for the Kaplan reconstructed data.
Potential of MODIS ocean bands for estimating CO2 flux from terrestrial vegetation: A novel approach
Authors: Rahman A. F. , Cordova V. D. , Gamon J. A. , Schmid H. P. , Sims D. A.
Published: May 2004

A physiologically‐driven spectral index using two ocean‐color bands of MODIS satellite sensor showed great potential to track seasonally changing photosynthetic light use efficiency (LUE) and stress‐induced reduction in net primary productivity (NPP) of terrestrial vegetation. Based on these findings, we developed a simple “continuous field” model solely based on remotely sensed spectral data that could explain 88% of variability in flux‐tower based daily NPP. For the first time, such a procedure is successfully tested at landscape level using satellite imagery. These findings highlight the unexplored potential of narrow‐band satellite sensors to improve estimates of spatial and temporal distribution in terrestrial carbon flux.
Determining the distribution and abundance of a regional koala population in south-east Queensland for conservation management
Authors: Dique David S. , Preece Harriet J. , Thompson Jim , Villiers Deidré L. de
Published: May 2004

Koala surveys were used to determine the distribution and abundance of a threatened regional koala population in south-east Queensland to assist with the development of effective conservation management programs. Daytime systematic searches of strip transects were conducted twice yearly from 1996 to 1999 to determine koala density at a number of sites in urban, remnant bushland and bushland strata. Mean density estimates for 27 survey sites ranged from 0.02 to 1.26 koalas ha–1. Koala densities were generally higher in large tracts and remnant patches of eucalypt bushland towards the centre of the region with lower but significant densities in urban areas. Two estimates of population size were obtained: 7230 (±1668, 95% confidence limit) and 6246 (±1444, 95% confidence limit). The estimate of 6246 was considered to provide a better indication of actual population size as it reduced the variation within strata and took into account the distribution of koalas across the region. It is likely that determining habitat areas for conservation based on where koalas actually occur rather than identifying distributions of 'preferred' tree species or community reports, as has been promoted in other studies, is a better indicator of the conservation significance of remnant habitat areas. Future koala-management programs should ensure that the significance of eucalypt bushland areas towards the centre of the study area is not compromised by future urban development and associated threats to koalas.
Sound recording of bird vocalisations in forests. I. Relationships between bird vocalisations and point interval counts of bird numbers - a case study in statistical modeling
Authors: Cunningham R. B. , Lindenmayer D. B. , Lindenmayer B. D.
Published: May 2004

Morning vocal activity data for birds were collected using automatic sound recorders at 165 sites in fragmented forests at Tumut in south-eastern Australia. A model was developed to describe the statistical properties of the vocal activity data and study the relationship between the number of 'elements' (or notes) broadcast by birds and the number of birds recorded by human observers. We discuss the practical issues of finding a model where variance heterogeneity and skewness is a feature of the data, while the context of the problem required that multiplicative relationships be preserved. A satisfactory fit to our vocal activity data was obtained by using a Gamma distribution.For most groups of birds, the observed relationships between vocal activity and the number of birds recorded by human point counts were weak but statistically significant.Our analysis suggests that these data provide limited useful information about vocal activity per bird. Automatic sound-recording data may be informative for drawing inferences about temporal patterns in vocal activity but do not seem useful as a method for estimating the abundance of birds. A significant relationship was identified between the number of species vocalising, as measured by sound recorders, and the number of species observed by point count method. However, the relationship was far from isometric and there were many more species detected by the sound recorders than by human observers.Results from analyses of vocal activity data gathered at Tumut were confirmed by additional data obtained in a subsequent, small calibration study in the Namadgi National Park in the Australian Capital Territory.
Availability of nest hollows and breeding population size of eclectus parrots, Eclectus roratus, on Cape York Peninsula, Australia
Authors: Legge S. , Heinsohn R. , Garnett S.
Published: May 2004

The distribution of the Australian mainland endemic subspecies of the eclectus parrot, Eclectus roratus macgillivrayi, is currently confined to the lowland rainforests of the Iron–McIlwraith Ranges of eastern Cape York Peninsula. Females breed in large hollows in emergent rainforest trees that are readily visible from above. Aerial surveys were used to sample 58% of the rainforest (454 km2) of the Iron Range region to estimate the density of these nest trees. Corrections for overcounting bias (not all observed emergent trees were active nest trees) and undercounting bias (not all active nest trees were visible from the air) were made by ground-truthing over 70 trees. The tree count data were treated in two different ways, producing estimates of 417 (s.e. = 25) and 462 (s.e. = 31) nest trees for the Iron Range region. Long-term observational data on the number of eclectus parrots associated with each nest tree were used to estimate the population size of eclectus parrots at Iron Range: 538–596 breeding females, and 1059–1173 males. These results have three implications. First, this relatively low population estimate suggests that the Australian subspecies of eclectus parrots should be considered vulnerable to habitat loss or perturbation, especially in light of their complex social system, male-biased adult sex ratio, low breeding success and high variance in reproductive success among females. Second, the low density of nest trees suggests that eclectus parrots are absent from the rainforests of Lockerbie Scrub and the Jardine dunefields because these areas are too small. Finally, if eclectus parrots persisted in the Iron–McIlwraith region during the rainforest contractions of Pleistocene glacial maxima (e.g. 14 000–17 000 years ago), the refugium in this region must have been fairly substantial in order to support a viable population – probably larger than previously assumed.
Long-range patterns of diversity and linkage disequilibrium surrounding the maize
Y1
gene are indicative of an asymmetric selective sweep
Authors: Palaisa Kelly , Morgante Michele , Tingey Scott , Rafalski Antoni
Published: May 2004

Both yellow and white corn occurs among ancestral open pollinated varieties. More recently, breeders have selected yellow endosperm variants of maize over ancestral white phenotypes for their increased nutritional value resulting from the up-regulation of the
Y1
phytoene synthase gene product in endosperm tissue. As a result, diversity within yellow maize lines at the
Y1
gene is dramatically decreased as compared to white corn. We analyzed patterns of sequence diversity and linkage disequilibrium in nine low copy regions located at varying distances from the
Y1
gene, including a homolog of the barley
Mlo
gene. Patterns consistent with a selective sweep, such as significant associations of informative single-nucleotide polymorphisms with endosperm color phenotype, linkage disequilibrium, and significantly reduced diversity within the yellow endosperm haplotypes, were observed up to 600 kb downstream of
Y1
, whereas the upstream region showed a more rapid recovery. The starch branching enzyme 1 (
sbe1
) gene is the first region downstream of
Y1
that does not have a highly conserved haplotype in the yellow endosperm germplasm.
A genome-wide screen for
Saccharomyces cerevisiae
deletion mutants that affect telomere length
Authors: Askree Syed H. , Yehuda Tal , Smolikov Sarit , Gurevich Raya , Hawk Joshua , Coker Carrie , Krauskopf Anat , Kupiec Martin , McEachern Michael J.
Published: May 2004

Telomeres are nucleoprotein structures present at the ends of eukaryotic chromosomes that play a central role in guarding the integrity of the genome by protecting chromosome ends from degradation and fusion. Length regulation is central to telomere function. To broaden our knowledge about the mechanisms that control telomere length, we have carried out a systematic examination of ≈4,800 haploid deletion mutants of
Saccharomyces cerevisiae
for telomere-length alterations. By using this screen, we have identified >150 candidate genes not previously known to affect telomere length. In two-thirds of the identified mutants, short telomeres were observed; whereas in one-third, telomeres were lengthened. The genes identified are very diverse in their functions, but certain categories, including DNA and RNA metabolism, chromatin modification, and vacuolar traffic, are overrepresented. Our results greatly enlarge the number of known genes that affect telomere metabolism and will provide insights into how telomere function is linked to many other cellular processes.
Microtubule-stabilizing agents based on designed laulimalide analogues
Authors: Mooberry Susan L. , Randall-Hlubek Deborah A. , Leal Rachel M. , Hegde Sayee G. , Hubbard Robert D. , Zhang Lei , Wender Paul A.
Published: May 2004

Laulimalide is a potent, structurally unique microtubule-stabilizing agent originally isolated from the marine sponge
Cacospongia mycofijiensis
. Laulimalide exhibits an activity profile different from other microtubule-binding agents, notably including effectiveness against paclitaxel-resistant cells, but it is intrinsically unstable. Five analogues of laulimalide were designed to exhibit enhanced chemical stability yet retain its exceptional biological activities. Evaluations of these analogues showed that all are effective inhibitors of cancer-cell proliferation yet differ substantially in potency with an IC
50
range of 0.12–16.5 μM. Although all of the analogues initiated cellular changes similar to laulimalide, including increased density of interphase microtubules, aberrant mitotic spindles, and ultimately apoptosis, differences among the analogues were apparent. The two most potent analogues, C
16
-C
17
-des-epoxy laulimalide and C
20
-methoxy laulimalide, appear to have a mechanism of action identical to laulimalide. The C
16
-C
17
-des-epoxy, C
20
-methoxy laulimalide derivative, which incorporates both chemical changes of the most potent analogues, was significantly less potent and initiated the formation of unique interphase microtubules unlike the parent compound and other analogues. Two C
2
-C
3
-alkynoate derivatives had lower potency, and they initiated abnormal microtubule structures but did not cause micronucleation or extensive G
2
/M accumulation. Significantly, paclitaxel- and epothilone-resistant cell lines were less resistant to the laulimalide analogues. In summary, analogues of laulimalide designed to minimize or eliminate its intrinsic instability have been synthesized, and some have been found to retain the unique biological activities of laulimalide.
Preliminary study of the prevalence of speech and language difficulties in young offenders
Authors: Bryan Karen
Published: May 2004

Background: There are no systematic surveys of the UK prison population, but data from several sources suggest that a significant number of prisoners might have limitations in their speech, language and communication abilities.

Aim: To examine the hypothesis that compared with the general population, a significantly larger number of the prison population has speech, language and communication difficulties.

Methods & Procedures: A survey of 10% of the young offenders within one young offender's institution was conducted. Tests of naming, picture description, grammatical competency and comprehension were used.

Outcomes & Results: Forty‐three per cent of participants scored at a level significantly lower than the limits acceptable for their age on the Boston Naming Test; 73% scored significantly below the acceptable limits for their age on grammatical competency; 23% scored significantly below the acceptable limits for their age on language comprehension; 47% of participants received more than one rating of moderate impairment on picture description.

Conclusion: It was confirmed that high levels of speech, language and communication difficulties are found among the young offender population. The implications for the management of young offenders, the limitations of the study and indications for further research are discussed.
Working memory and novel word learning in children with hearing impairment and children with specific language impairment
Authors: Hansson K. , Forsberg J. , Löfqvist A. , Mäki‐Torkko E. , Sahlén B.
Published: May 2004

Background: Working memory is considered to influence a range of linguistic skills, i.e. vocabulary acquisition, sentence comprehension and reading. Several studies have pointed to limitations of working memory in children with specific language impairment. Few studies, however, have explored the role of working memory for language deficits in children with hearing impairment.

Aims: The first aim was to compare children with mild‐to‐moderate bilateral sensorineural hearing impairment, children with a preschool diagnosis of specific language impairment and children with normal language development, aged 9–12 years, for language and working memory. The special focus was on the role of working memory in learning new words for primary school age children.

Methods & Procedures: The assessment of working memory included tests of phonological short‐term memory and complex working memory. Novel word learning was assessed according to the methods of Gilbertson and Kamhi (1995). In addition, a range of language tests was used to assess language comprehension, output phonology and reading.

Outcomes & Results: Children with hearing impairment performed significantly better than children with a preschool diagnosis of specific language impairment on tasks assessing novel word learning, complex working memory, sentence comprehension and reading accuracy. No significant correlation was found between phonological short‐term memory and novel word learning in any group. The best predictor of novel word learning in children with specific language impairment and in children with hearing impairment was complex working memory. Furthermore, there was a close relationship between complex working memory and language in children with a preschool diagnosis of specific language impairment but not in children with hearing impairment.

Conclusions: Complex working memory seems to play a significant role in vocabulary acquisition in primary school age children. The interpretation is that the results support theories suggesting a weakened influence of phonological short‐term memory on novel word learning in school age children.
Theorems on sets not belonging to algebras
Authors: Grinblat L.
Published: May 2004

Let

A

1

,
…
,

A

n

,

A

n
+
1

\mathcal {A}_1,\dots , \mathcal {A}_n, \mathcal {A}_{n+1}

be a finite sequence of algebras of sets given on a set

X
X

,

⋃

k
=
1

n

A

k

≠

P

(
X
)

\bigcup _{k=1}^n \mathcal {A}_k \ne \mathfrak {P}(X)

, with more than

4
3

n

\frac {4}{3}n

pairwise disjoint sets not belonging to

A

n
+
1

\mathcal {A}_{n+1}

. It has been shown in the author’s previous articles that in this case

⋃

k
=
1

n
+
1

A

k

≠

P

(
X
)

\bigcup _{k=1}^{n+1} \mathcal {A}_k \ne \mathfrak {P}(X)

. Let us consider, instead of

A

n
+
1

\mathcal {A}_{n+1}

, a finite sequence of algebras

A

n
+
1

,
…
,

A

n
+
l

\mathcal {A}_{n+1}, \dots , \mathcal {A}_{n+l}

. It turns out that if for each natural

i
≤
l

i \le l

there exist no less than

4
3

(
n
+
l
)
−

l
24

\frac {4}{3}(n+l)- \frac {l}{24}

pairwise disjoint sets not belonging to

A

n
+
i

\mathcal {A}_{n+i}

, then

⋃

k
=
1

n
+
l

A

k

≠

P

(
X
)

\bigcup _{k=1}^{n+l} \mathcal {A}_k \ne \mathfrak {P}(X)

. Besides this result, the article contains: an essentially important theorem on a countable sequence of almost

σ
\sigma

-algebras (the concept of almost

σ
\sigma

-algebra was introduced by the author in 1999), a theorem on a family of algebras of arbitrary cardinality (the proof of this theorem is based on the beautiful idea of Halmos and Vaughan from their proof of the theorem on systems of distinct representatives), a new upper estimate of the function

v

(
n
)

\mathfrak {v}(n)

that was introduced by the author in 2002, and other new results.
Is It Who You Know? Entrepreneurs and Bankers in São Paulo, Brazil, at the Turn of the Twentieth Century
Authors: Hanley Anne
Published: May 2004

This article examines the trust-producing mechanisms investors and financiers used in São Paulo, Brazil, to determine where to invest their money in the late nineteenth and early twentieth centuries. The coffee boom that began in the 1880s spurred bursts of new domestic business development that transformed São Paulo into Brazil's industrial leader. Using shareholder and director data from an array of business sectors, this article demonstrates that early development (1856–1905) of the institutions that provided business finance was accompanied by highly personal relationships between financier and entrepreneur. By the early twentieth century (1906–1920), rapid economic growth and business diversification rendered these personal connections inadequate and hence less important to business finance. Investors and directors concentrated their energies and their money, abandoning the practice of forming broad connections in general—and connections to a bank in particular—and turned to the stock market instead. By providing an alternative to personal forms of trust production, the rise of impersonal intermediation promoted the significantly broadened market for corporate business formation that underwrote São Paulo's economic transformation.
Lawyers' Contribution to Business Development in Early Twentieth-Century Mexico
Authors: Recio Gabriela
Published: May 2004

The Mexican Revolution (1910) brought important changes to the social, political and economic spheres of Mexico. New legislation was passed to protect workers and redistribute land. The state acquired rights to petroleum, water, and subsoil minerals. For entrepreneurs this was an abrupt change from the previous regime. They had to adapt to the new policies and administrative state structure. Business lawyers aided companies in a country where the government had circumscribed the private sector's participation in the economy. Lawyers offered their clients important services, such as lobbying and aid in corporate restructuring. This article explores how in the midst of these new revolutionary regimes an important investment group used the services of business lawyer Manuel Gómez Morin to create Mexico's first holding company and to issue the first mortgage bonds in the country.
Gut-homing (α 4 β 7 +) Th1 memory responses after inactivated poliovirus immunization in poliovirus orally pre-immunized donors
Authors: Krieg Carsten , Maier Reinhard , Meyerhans Andreas
Published: May 2004

Mucosal infections are prevented by a specialized local immune system. Immune cells of this compartment can also be found in the blood and are characterized by the expression of mucosa-specific homing molecules. Here, the cellular immune responses after inactivated poliovirus immunization (IPV) in poliovirus orally pre-immunized donors were investigated. Subcutaneous IPV induced a transient increase in the proliferative response against poliovirus antigen and in the number of poliovirus-specific CD4+T cells in the blood of the vaccinees. These cells were characterized to be of the effector memory type (CD45RA−/CD45RO+/CCR7−/CD27+) and expressed the homing moleculeα4β7, indicating their origin from the gut. Together these data show the recurrence of gut-derived poliovirus-specific cells upon IPV and evaluate the whole-blood assay as a powerful tool for monitoring the success of a vaccination.
Towards a shared understanding of skill shortages: differing perceptions of training and development needs
Authors: Skinner Denise , Saunders Mark N.K. , Beresford Richard
Published: May 2004

The question of how to develop human capabilities to meet current and future needs of organisations has become an important issue at national, organisational and individual levels. An essential ingredient is shared understanding of the skills and competences deemed necessary and/or desirable for current and future performance. Current indications in the UK are that this may not exist and that there is an incompatibility between supply and demand. This paper reports on a research project undertaken in the UK automotive sector to explore the extent and nature of the differences in perception among stakeholders relating to the skills and development needs of current and future employees. Using the template approach data were collected from those providing training and those who are consumers of training. Comparison identified competing demands and differences in expectation and attainment, particularly in relation to prospective employees, potentially resulting in dissatisfaction and disappointment for all concerned.
Contributions to the experimental validation of the discrete element method applied to tumbling mills
Authors: McBride Andrew , Govender Indresan , Powell Malcolm , Cloete Trevor
Published: May 2004

Accurate 3D experimental particle trajectory data, acquired from a laboratory tumbling mill using bi‐planar X‐ray filming, are used to validate the discrete element method (DEM). Novel numerical characterisation techniques are presented that provide a basis for comparing the experimental and simulated charge behaviour. These techniques are based on fundamental conservation principles, and provide robust, new interpretations of charge behaviour that are free of operator bias. Two‐ and three‐dimensional DEM simulations of the experimental tumbling mill are performed, and the relative merits of each discussed. The results indicate that in its current form DEM can simulate some of the salient features of the tumbling mill charge, however, comparison with the experiment indicate that the technique requires refinement to adequately simulate all aspects of the system.
Discrete element method
Authors: Yu A.B.
Published: May 2004

Discrete element method (DEM) has been extensively used in the laboratory of particulate and multiphase processing at the University of New South Wales (UNSW) to study the fundamentals of particulate matter at a particle scale. This paper briefly reviews the work in the laboratory, which covers the development of simulation techniques and their application to the study of particle packing and flow, transport properties and constitutive relationships of typical static or dynamic particulate systems. It is concluded, through representative comparison between simulated and measured results under different conditions, that DEM, as a major technique for discrete particle simulation, is an effective method for particle scale research of particulate matter.
Contact resolution algorithm for an ellipsoid approximation for discrete element modeling
Authors: Johnson Scott , Williams John R. , Cook Benjamin
Published: May 2004

The efficiency of a discrete element implementation relies on several factors, including the particle representation, neighbor‐sorting algorithm, contact resolution, and force generation. The focus of this paper is on the four‐arc approximation for an ellipsoid – a geometrical representation useful in simulations of large numbers of smoothly shaped particles. A new contact resolution algorithm based on the four‐arc approximation is presented, which takes advantage of the properties of the geometry to provide favorable empirical convergence properties compared with the method proposed earlier. Special attention is given to the software implementation of the algorithm, and a discussion of the computational efficiency of the algorithm is provided.
A 2D polygon/polygon contact model: algorithmic aspects
Authors: Feng Y.T. , Owen D.R.J.
Published: May 2004

This paper proposes an energy‐based general polygon to polygon normal contact model in which the normal and tangential directions, magnitude and reference contact position of the normal contact force are uniquely defined. The model in its final form is simple and elegant with a clear geometric perspective, and also possesses some advanced features. Furthermore, it can be extended to a more complex situations and in particular, it may also provide a sound theoretical foundation to possibly unifying existing contact models for all types of (convex) objects.
A particle center based homogenization strategy for granular assemblies
Authors: D'Addetta G.A. , Ramm E. , Diebels S. , Ehlers W.
Published: May 2004

In this paper, a new homogenization technique for the determination of dynamic and kinematic quantities of representative elementary volumes (REVs) in granular assemblies is presented. Based on the definition of volume averages, expressions for macroscopic stress, couple stress, strain and curvature tensors are derived for an arbitrary REV. Discrete element model simulations of two different test set‐ups including cohesionless and cohesive granular assemblies are used as a validation of the proposed homogenization technique. A non‐symmetric macroscopic stress tensor, as well as couple stresses are obtained following the proposed procedure, even if a single particle is described as a standard continuum on the microscopic scale.
Factors impacting on e‐business adoption and development in the smaller firm
Authors: Fillis Ian , Johannson Ulf , Wagner Beverly
Published: May 2004

Globalisation and technology effects appear to have spurred smaller firms around the world to embrace e‐business practices. However, there is considerable variability in adoption and usage from country to country. Drawing on existing research on e‐business and conventional business and marketing in the smaller firm, this paper formulates a conceptual framework of reasons behind adoption and non‐adoption in the smaller firm. Macro dimensions, industry sector and firm‐level factors are analysed, together with owner/manager motivations and attitudes towards e‐business adoption. A conceptual framework is constructed and research propositions are then developed in order to focus attention on sets of internal and external factors which impact on smaller firm e‐business usage. Recommendations for future theory development are presented, together with implications for industry bodies involved in supporting the SME sector.
Global corporate governance: debates and challenges
Authors: Praveen Bhasa Malla
Published: May 2004

Modern day business is beset with changing operating paradigms. Economies with efficient economic policies and stable political systems are a big draw among the investors. Countries that have opened themselves to world markets and that have good legal systems in place, providing protection to investors have attracted more capital in the process of globalization. As the demand for capital is growing in both the developed and the developing economies, the need to establish good governance practices has gained momentum. Governance practices however, are not uniform across nations. This diversity may be particularly because of the different legal structures and cultural settings adopted by different nations. This paper tries to explore the arguments on convergence and divergence of corporate best practices, keeping in view the various governance models currently in practice. Explaining the rationale behind the emergence of corporate governance as a movement, this paper attempts at discussing the various prevalent systems of governance. In the end an attempt is made to address the challenges to corporate governance in the context of globalization of best practices. Given the cultural settings of different nations it is argued that it would never be possible for corporate laws to converge universally. New models of corporate governance are likely to emerge given the large‐scale experimentation done by transition economies.
Control of the treasury function
Authors: Helliar Christine , Dunne Theresa
Published: May 2004

High profile disasters such as those experienced at Barings in 1995 and more recently at Enron and AIB Group, have resulted in increasing attention being focused on the internal control procedures of companies, in particular on the control mechanisms and processes in place in treasury departments. This paper uses interviews to investigate the internal control procedures at 11 treasury departments in the UK.
Hazard Models for Line Transect Surveys with Independent Observers
Authors: Skaug Hans J. , Schweder Tore
Published: May 2004

Summary. The likelihood function for data from independent observer line transect surveys is derived, and a hazard model is proposed for the situation where animals are available for detection only at discrete time points. Under the assumption that the time points of availability follow a Poisson point process, we obtain an analytical expression for the detection function. We discuss different criteria for choosing the hazard function and consider in particular two different parametric families of hazard functions. Discrete and continuous hazard models are compared and the robustness of the discrete model is investigated. Finally, the methodology is applied to data from a survey for minke whales in the northeastern Atlantic.
Estimation of Offspring Production from a Limited Number of Stage‐Structured Censuses
Authors: Bakke Øyvind , Lorentsen Svein‐Håkon
Published: May 2004

Summary. We propose a procedure for maximum likelihood estimation of the number of animals or offspring in a closed population where the individuals counted go through stages or age‐groups. Application of the procedure requires knowledge of the distributions of the stage durations. A procedure for maximum likelihood estimation of those based on marked animals is also given. The procedures are illustrated by applying them to gray seal (Halichoerus grypus) data from Froan Nature Reserve, Central Norway, from the breeding seasons 1990–1999.