bluuebunny/crossref_metadata_2025 huggingface dataset:
Ab initio n-electron valence state perturbation theory study of the adiabatic transitions in carbonyl molecules: Formaldehyde, acetaldehyde, and acetone
Authors: Angeli Celestino , Borini Stefano , Ferrighi Lara , Cimiraglia Renzo
Published: March 2005

The application of the recently developed second-order n-electron valence state perturbation theory (NEVPT2) to small carbonyl molecules (formaldehyde, acetaldehyde, and acetone) is presented. The adiabatic transition energies are computed for the singlet and triplet n→π*, π→π*, and σ→π* states performing a full geometry optimization of the relevant states at the single state CASSCF level and taking into account the zero point energy correction in the harmonic approximation. The agreement with the known experimental values and with previously published high level calculations confirms that NEVPT2 is an efficient tool to be used for the interpretation of molecular electronic spectra. Moreover, different insight into the nature of the excited states has been obtained. Some of the transitions presented here have never been theoretically computed previously [(π→π*)3 and (σ→π*)3 adiabatic transitions in acetaldehyde and acetone] or have been studied only using moderate level (single reference based) ab initio methods (all adiabatic transitions in acetaldehyde). In the present work a consistent disagreement between NEVPT2 and experiment has been found for the (π→π*)3 adiabatic transition in all molecules: this result is attributed to the low intensity of the transition to the first vibrational levels of the excited state. The n→π* singlet and triplet vertical transition energies are also reported for all the molecules.
Test of a nonempirical density functional: Short-range part of the van der Waals interaction in rare-gas dimers
Authors: Tao Jianmin , Perdew John P.
Published: March 2005

It is known that the nonempirical generalized gradient approximation (GGA) of Perdew, Burke, and Ernzerhof (PBE) provides a much more realistic description of the short-range part of the van der Waals (vdW) interaction than does the local spin density (LSD) approximation. In the present work, the ability of the higher-level nonempirical meta-GGA of Tao, Perdew, Staroverov, and Scuseria (TPSS) to describe vdW interaction is tested self-consistently in ten rare-gas dimers with Z⩽36. The one-parameter hybrid version (TPSSh) of the TPSS exchange-correlation functional is also included in this test. Calculations show that both TPSS and TPSSh functionals correctly yield vdW bonds in these dimers and significantly improve the prediction of bond lengths, binding energies, and harmonic vibrational frequencies over LSD. The rather close agreement of TPSS with PBE for these dimers confirms a principle of the TPSS construction: preservation of the PBE large-gradient behavior. More importantly, it suggests that TPSS can serve as a platform on which to construct a still-higher level of nonempirical functionals. Compared with the PBE GGA, TPSS, and TPSSh yield a slightly weaker binding. As for normally bonded molecules, TPSSh yields the most accurate vibrational frequencies. The typically too-long bond lengths and too-small binding energies of TPSS meta-GGA suggest the need for some long-range vdW interaction correction even in this class of systems. The effect of basis-set superposition error on the calculated properties of these vdW systems is investigated. We also show that the relatively strong anharmonic effects in the rare-gas dimers are described remarkably well by the Morse potential.
Relative angle determinable stitching interferometry for hard x-ray reflective optics
Authors: Mimura Hidekazu , Yumoto Hirokatsu , Matsuyama Satoshi , Yamamura Kazuya , Sano Yasuhisa , Ueno Kazumasa , Endo Katsuyoshi , Mori Yuzo , Yabashi Makina , Tamasaku Kenji , Nishino Yoshinori , Ishikawa Tetsuya , Yamauchi Kazuto
Published: March 2005

Metrology plays an important role in surface figuring with subnanometer accuracy. We have developed relative angle determinable stitching interferometry for the surface figuring of elliptical mirrors, in order to realize hard x-ray nanofocusing. In a stitching system, stitching angles are determined not by the general method using a common area between neighboring shots, but by the new method using the mirror’s tilt angles measured at times when profile data are acquired. The high measurement accuracy of approximately 4nm (peak-to-valley) was achieved in the measurement of a cylindrical surface having the same curvature as the elliptically designed shape to enable hard x-ray nanofocusing.
Enhancement of breakdown voltage by AlN buffer layer thickness in AlGaN∕GaN high-electron-mobility transistors on 4in. diameter silicon
Authors: Arulkumaran S. , Egawa T. , Matsui S. , Ishikawa H.
Published: March 2005

Enhancement of breakdown voltage (BV) with the increase of AlN buffer layer thickness was observed in AlGaN∕GaN high-electron-mobility transistors (HEMTs) grown by metalorganic chemical vapor deposition on 4in. Si. The enhancement of device performance with AlN buffer thickness (200 and 300nm) is due to the reduction of electrically active defects from Si substrate. The reduction of defects from Si with the increase of AlN thickness was confirmed by x-ray rocking curve measurements. Not much change has been observed in ON-state BV (BV:ON) values except in devices with 500-nm-thick buffer layer. About 46% enhancement in OFF-state BV (BV:OFF) was observed on 200μm wide HEMTs with 300nm thick AlN buffer layer when compared to HEMTs with 8nm thick AlN buffer layer. The location of junction breakdown in the device was identified as GaN∕AlN∕Si interface. The measured specific on-resistance (Ron) values for 200 and 400μm wide HEMTs with 300nm thick buffer layers were 0.28 and 0.33mΩcm2, respectively. About an order of low Ron was observed when compared with the reported values. The AlGaN∕GaN HEMTs on 4in. Si with thicker AlN buffer layers are suitable for high-power applications.
Quasi-periodic planar metamaterial substrates
Authors: Li Hongqiang , Hang Zhihong , Qin Yaqin , Wei Zeyong , Zhou Lei , Zhang Yewen , Chen Hong , Chan C. T.
Published: March 2005

We report our experimental and theoretical studies on a metamaterial substrate consisting of a quasi-periodic metallic planr pattern and a flat metal sheet, interconnected through metallic vias. We show that this structure possesses multiple in-phase reflection frequency regimes and spectral gaps for transverse-magnetic surface waves, whereas the transverse-electric surface waves are suppressed in all frequencies. In particular, an antenna put on top of this planar structure radiates with very high directivity (D=240) at some frequencies. This phenomenon is mainly governed by the inhomogeneity of the structure, which is a collective effect of perfect magnetic and electric conductors operating simultaneously at the frequency.
Magnetoelectric CoFe2O4–Pb(Zr,Ti)O3 composite thin films derived by a sol-gel process
Authors: Wan J. G. , Wang X. W. , Wu Y. J. , Zeng M. , Wang Y. , Jiang H. , Zhou W. Q. , Wang G. H. , Liu J.-M.
Published: March 2005

Magnetoelectric (ME) CoFe2O4–Pb(Zr,Ti)O3 composite thin films have been prepared by a sol-gel process and spin-coating technique. X-ray diffraction and scanning electron microscopy reveal that there exists local aggregation or phase separation of the CoFe2O4 and Pb(Zr,Ti)O3 phases in the films. Vibrating sample magnetometer, ferroelectric test unit, and magnetoelectric measuring device were used to characterize the magnetic and ferroelectric properties, as well as the ME effect of the films. It is shown that the films exhibit both good magnetic and ferroelectric properties, as well as a ME effect. A high initial magnetoelectric voltage coefficient for the film is observed. The ME effect of the film strongly depends on the magnetic bias and magnetic field frequency.
Force production by depolymerizing microtubules: A theoretical study
Authors: Molodtsov M. I. , Grishchuk E. L. , Efremov A. K. , McIntosh J. R. , Ataullakhanov F. I.
Published: March 2005

Chromosome movement during mitosis is powered in part by energy released through the depolymerization of kinetochore microtubules (MTs). Strong but indirect evidence suggests the existence of a specialized coupling between kinetochores and MT plus ends that enables this transduction of chemical energy into mechanical work. Analysis of this phenomenon is important for learning how energy is stored within the MT lattice, how it is transduced, and how efficient the process can be, given coupling devices of different designs. Here we use a recently developed molecular-mechanical model of MTs to examine the mechanism of disassembly dependent force generation. Our approach is based on changes in tubulin dimer conformation that occur during MT disassembly. We find that all of the energy of polymerization-associated GTP hydrolysis can be stored as deformations of the longitudinal bonds between tubulin dimers, and its optimal use does not require the weakening of lateral bonds between dimers. Maximum utilization of this stored energy and, hence, the generation of the strongest possible force, is achieved by a protofilament power-stroke mechanism, so long as the coupling device does not restrict full dissociation of the lateral bonds between tubulin dimers.
Evidence for cross-genotype neutralization of hepatitis C virus pseudo-particles and enhancement of infectivity by apolipoprotein C1
Authors: Meunier Jean-Christophe , Engle Ronald E. , Faulk Kristina , Zhao Ming , Bartosch Birke , Alter Harvey , Emerson Suzanne U. , Cosset Francois-Loic , Purcell Robert H. , Bukh Jens
Published: March 2005

The lack of a cell culture system to support hepatitis C virus (HCV) replication has hampered studies of this frequent cause of chronic liver disease. However, pseudotyped retroviral particles (pp) bearing the HCV envelope glycoproteins have provided a different approach to HCV studies. We used genotype 1a pp to detect neutralizing antibodies (NtAb) in eight chimpanzees and four humans infected with 1a strains, and developed pp of genotypes 2a, 3a, 4a, 5a, and 6a to study crossreactivity. NtAb was detected in one of four chimpanzees and none of three humans with acute resolving infection, suggesting that NtAb is not required for HCV clearance. NtAb were detected at high titer in two of four chimpanzees and, in Patient H, all with persistent infection; responses paralleled humoral responses to envelope 1 and 2 proteins and, in some cases, correlate also with antibodies to the hypervariable region 1, previously thought to be the primary site of neutralization. NtAb raised during 1a infections could neutralize HCVpp of genotypes 4a, 5a, and 6a but had only limited reactivity against 2a and 3a. The detection of high-titer NtAb with cross-genotype reactivity has important implications for the development of active and passive immune-prophylaxis strategies against HCV. Finally, we found that HCVpp infectivity was enhanced by human or chimpanzee sera; apolipoprotein C1 alone or as a component of high-density lipoproteins caused this enhancement. Future studies of the
in vivo
role of apolipoprotein C1 might provide additional insights into the infection process of HCV.
CFTR Gating II
Authors: Bompadre Silvia G. , Cho Jeong Han , Wang Xiaohui , Zou Xiaoqin , Sohma Yoshiro , Li Min , Hwang Tzyh-Chang
Published: March 2005

Previously, we demonstrated that ADP inhibits cystic fibrosis transmembrane conductance regulator (CFTR) opening by competing with ATP for a binding site presumably in the COOH-terminal nucleotide binding domain (NBD2). We also found that the open time of the channel is shortened in the presence of ADP. To further study this effect of ADP on the open state, we have used two CFTR mutants (D1370N and E1371S); both have longer open times because of impaired ATP hydrolysis at NBD2. Single-channel kinetic analysis of ΔR/D1370N-CFTR shows unequivocally that the open time of this mutant channel is decreased by ADP. ΔR/E1371S-CFTR channels can be locked open by millimolar ATP with a time constant of ∼100 s, estimated from current relaxation upon nucleotide removal. ADP induces a shorter locked-open state, suggesting that binding of ADP at a second site decreases the locked-open time. To test the functional consequence of the occupancy of this second nucleotide binding site, we changed the [ATP] and performed similar relaxation analysis for E1371S-CFTR channels. Two locked-open time constants can be discerned and the relative distribution of each component is altered by changing [ATP] so that increasing [ATP] shifts the relative distribution to the longer locked-open state. Single-channel kinetic analysis for ΔR/E1371S-CFTR confirms an [ATP]-dependent shift of the distribution of two locked-open time constants. These results support the idea that occupancy of a second ATP binding site stabilizes the locked-open state. This binding site likely resides in the NH2-terminal nucleotide binding domain (NBD1) because introducing the K464A mutation, which decreases ATP binding affinity at NBD1, into E1371S-CFTR shortens the relaxation time constant. These results suggest that the binding energy of nucleotide at NBD1 contributes to the overall energetics of the open channel conformation.
Serotype incidence and antibiotic susceptibility of Streptococcus pneumoniae causing invasive disease in Scotland, 1999–2002
Authors: Denham B C , Clarke S C
Published: March 2005

Pneumococcal disease remains an important cause of invasive and non-invasive disease in Scotland and elsewhere. The Scottish Meningococcus and Pneumococcus Reference Laboratory receives isolates of Streptococcus pneumoniae from diagnostic laboratories around Scotland. Here, the serogroups/types and antibiotic-susceptibility patterns of invasive isolates received between 1999 and 2002 are described. There were a total of 1741 invasive isolates received, the most common serogroups/types being 14 (19.8 %), 9 (10.2 %), 6 (8.3 %), 19 (7.9 %), 23 (7.9 %), 4 (6.5 %), 8 (6.4 %), 3 (5.7 %), 1 (3.8 %), 7 (3.8 %) and 18 (3.4 %). Importantly, serotypes 7 and 8 are not represented in the 7-, 9- and 11-valent pneumococcal conjugate polysaccharide vaccines. There were 67 (3.8 %) isolates considered penicillin non-susceptible, although no penicillin resistance (MIC ⩾ 0.002 mg ml−1) was recorded. One hundred and ninety-four (11.1 %) isolates, predominantly of serotype 14, were resistant to erythromycin, and 12 (0.7 %) were resistant to ciprofloxacin. This information provides an important dataset that will prove essential prior to and during the implementation of pneumococcal conjugate vaccines in the UK.
International presence and impact of the UK biomedical research, 1989‐2000
Authors: Webster Berenika M.
Published: March 2005

Purpose

To map UK biomedical research by analysing biomedical publications from authors with UK institutional affiliation and indexed in Science Citation Index (SCI) and Social Sciences Citation Index (SSCI).

Design/methodology/approach

Bibliometric methods to assess the volume of research published, its impact and sources of funding of biomedical research in the UK are used. The analyses also include an examination of national and international collaboration, leading regions and institutions (by volume of output), types of research carried out and its potential impact factor. This was done for all of biomedicine and 32 selected sub‐fields. The data used span 12 years, allowing changes and developments over time to be tracked.

Findings

The UK's position as the second largest producer of biomedical research is under threat from Japan and Germany and other countries with traditionally weaker biomedical research base. Strength in malaria and asthma research and relative weakness in surgery and renal medicine is notable. The profile of UK biomedical research has changed significantly in the period analysed, with a doubling of the level of international collaboration, a significant increase in basic research papers and an increase in the potential impact of UK publications. A relative decrease of acknowledgement of UK Government funding was noted, as were increased acknowledgements to UK not‐for‐profit and international organisations.

Practical implications

Bibliometric analyses can provide reliable tools in mapping the development of scholarly disciplines which can be of use, as demonstrated in this paper, in research policy, as well as in domain analysis in information science, library collection development or publishing.

Originality/value

Apart from policy applications, bibliometric research of this type can provide valuable information about changes in the patterns of scholarly communication within a domain (areas of interest in sociology of science and information science) and inform collection development policies in libraries and information centres (by describing literatures: ageing and obsolescence, volume and impact).
E‐books in an academic library: implementation at the ETH Library, Zurich
Authors: McLuckie Ann
Published: March 2005

Purpose

To provide some insight into the phenomenon of e‐books and their potential application in general, and to describe how the ETH‐Bibliothek, an academic library, has integrated web‐based e‐books into its collection.

Design/methodology/approach

The concept of e‐books was examined and the success (or failure) of their integration into library collections evaluated. How web‐based e‐books have been integrated into the ETH‐Bibliothek's collection was evaluated, as there were different formats and pricing models for e‐books. Other important issues relevant to e‐books were considered, such as usage statistics, how to discover new e‐books for integration into a collection, and whether web‐based e‐books are likely to be applied successfully in academic libraries.

Findings

The implementation of e‐books at the Swiss Federal Institute of Technology (Eidgenössische Technische Hochschule) in Zurich is described, and information is provided on publishers or aggregators through which the ETH has subscribed to e‐books, different formats and pricing models for e‐books and usage statistics. How the number of e‐books to which an institution subscribes can be increased, is described, together with the benefits of e‐books in the academic environment, which will in all likelihood ensure the ongoing future of web‐based e‐books.

Originality/value

The paper provides introductory information on e‐books in general and on their suitability to an academic library in particular.
UNLV's Lied Library: a graphical time line
Authors: Vaughan Jason
Published: March 2005

Purpose

To chronicle the planning, construction and subsequent operation of UNLV's Lied Library.

Design/methodology/approach

Traces the critical milestones associated with the above.

Findings

The history chronicled herein has been dynamic, to say the least, and has yet to slow down.

Practical implications

Serves as a basis for similar developments still in the pipeline.

Originality/value

Could be a model for anyone contemplating establishing a future modern technology‐centred academic library.
Monitoring the effectiveness of anticoagulation control
Authors: Utley Martin , Patterson David , Gallivan Steve
Published: March 2005

Purpose

To assess the quality of anticoagulation control at an out‐patient clinic and to investigate patterns of deviation from therapeutic ranges.

Design/methodology/approach

Records for 36,157 clinic visits (2,050 patients) were studied. The quality of anticoagulation control was assessed by comparing the measurement of pro‐thrombin time recorded at each clinic visit, expressed as an international normalised ratio (INR), with the target therapeutic range for that patient, also recorded at the time of the clinic visit. Each INR measurement was classified according to the relevant patient's therapeutic range and the signed difference between the INR measurement and the centre of the therapeutic range was calculated. For each patient the percentage of their INR measurements that lay within their therapeutic range was calculated.

Findings

Of the measurements, 52.3 per cent were within the relevant therapeutic range. The proportion of individual patients' INR measurements within range varied greatly (median 52 per cent, inter‐quartile range 40‐65 per cent). The quality of anticoagulation control, as measured by the proportion of patients within their therapeutic range, changed little with patient follow‐up time.

Originality/value

The quality of anticoagulation control reported is comparable with that at other centres. The vast majority of patients spend periods outside the therapeutic range for their condition. There may be considerable room for improvement.
Attitude and age differences in online buying
Authors: Sorce Patricia , Perotti Victor , Widrick Stanley
Published: March 2005

Purpose

This paper examines the shopping and buying behavior of younger and older online shoppers as mediated by their attitudes toward internet shopping.

Design/methodology/approach

Over 300 students and staff from a US university completed a survey regarding their online shopping and buying experiences for 17 products.

Findings

The results show that, while older online shoppers search for significantly fewer products than their younger counterparts, they actually purchase as much as younger consumers. Attitudinal factors explained more variance in online searching behavior. Age explained more variance in purchasing behavior if the consumer had first searched for the product online.

Research limitations/implications

The limitations of the present research are threefold. First, the sample was restricted to university faculty, staff and students. Second, a better measure of the hedonic motivation construct is needed. Third, additional independent measures such as income should be included to understand the additional demographic factors related to online purchase.

Practical implications

Retailing managers can make use of the results as describing multifaceted nature of online shopping and buying behavior. Age differences (in both directions) were seen for many product categories. In addition, results indicate that how one measures online shopping impacts on one's understanding of age effects on internet shopping. Age was negatively correlated with online pre‐purchase search but was positively correlated with online purchasing when pre‐purchase search behavior was taken into account.

Originality/value

The present study advances knowledge of the nature of the relationships among age, attitudes, and online shopping and buying behavior.
Potential problems with removing scales before surgical transmitter implantation
Authors: Bauer C.
Published: March 2005

Thirty one mirror carp Cyprinus carpio were implanted with telemetry transmitters. Several large scales were removed from the incision area of two mirror carp before implantation of transmitters. When the fish were recaptured after 4 months, the mirror carp from which scales were removed showed severe tissue necrosis at the incision site whereas intact fish did not.
Diel vertical migrations of bathypelagic perch fry
Authors: Čech M. , Kratochvíl M. , Kubečka J. , Draštík V. , Matěna J.
Published: March 2005

The behaviour of young‐of‐the‐year (YOY) perchPerca fluviatilisas a dominant species in the assemblage of fry in the pelagic of Slapy Reservoir (Czech Republic), was studied during late May and mid‐June 2002 using acoustic methods and complementary net catches. During the day, perch fry were present simultaneously in littoral, epipelagic and bathypelagic habitats. Bathypelagic perch fry, forming a scattering layer, migrated vertically each day between the epilimnion and hypolimnion, with an amplitude of 11·0 m in May and 12·5 m in June. At dusk, the migratory bathypelagic fry mixed in the epilimnion with non‐migrating epipelagic fry and spent the night close to the thermocline (abundance maximum at 3–4 m in May, 0–2 m in June). In June, shoaling behaviour by some of the bathypelagic perch fry was also observed: the shoaling fry remained higher in the water column than the non‐shoaling fry. Both depths of the scattering layer and the depths of the fry shoals were strongly controlled by the light intensity. The contribution of the bathypelagic part of the population to the total numbers of pelagic perch fry decreased from 28·1% in May to 4·7% in June, while the density of all pelagic perch fry increased (c. 96 000 individuals ha−1in May and 142 000 individuals ha−1in June). In May, the bathypelagic (average total length,LT, 11·9 mm) and epipelagic (averageLT14·6 mm) perch fry differed in size while, in June, the epipelagic fry were divided into two distinct size groups. The more abundant group, of small epipelagic perch fry (averageLT14·6 mm), was similar in size to the bathypelagic fry (averageLT14·6 mm) while the less abundant group, of larger epipelagic fry (averageLT34·4 mm), was similar in size to littoral perch fry (averageLT35·0 mm). The results suggest that in perch fry three different survival strategies with different risks can be used in the same locality, time and year.
Larval description of the sympatric species, Craterocephalus stercusmuscarum stercusmuscarum(Pisces: Atherinidae) and Mogurnda adspersa(Pisces: Eleotridae) from tropical streams of north‐east Queensland, Australia
Authors: Close P. G. , Pusey B. J. , Arthington A. H.
Published: March 2005

Descriptions and illustrations of stages in the larval development of two common sympatric freshwater fishes in streams of tropical north‐east Queensland, the fly‐specked hardyhead Craterocephalus stercusmuscarum stercusmuscarum and the purple‐spotted gudgeon Mogurnda adspersa are presented. Larval development is described in terms of ontogenetic changes in gross morphology, notochord morphology, pigmentation, finfold morphology and fin structure. Developmental changes during the larval period of C. s. stercusmuscarum are similar to other atheriniformes, especially the genus Melanotaenia. The highly variable development and advanced state at hatching of M. adspersa in tropical streams contrasts with larval development of disjunct populations of the same species in southern Australia and also with other closely related species of the Eleotridae described elsewhere. Larvae of M. adspersa can be distinguished from C. s. stercusmuscarum on the basis of six key characters: pigmentation, presence of a pre‐anal ventral finfold, general body form and shape, number of post‐anal myomeres, notochord morphology at hatching and timing of swimbladder inflation. Characters that allow for the accurate discrimination between both of these species and other sympatric atheriniformes are identified.
Movement and mortality of stocked brown trout in a stream
Authors: Aarestrup K. , Jepsen N. , Koed A. , Pedersen S.
Published: March 2005

The movement and mortality of stocked brown trout Salmo trutta were investigated using radio telemetry. Four brown trout left the study area whereas the remaining fish were stationary. After 5 weeks, 13 out of 50 tagged brown trout were still alive in the stream. Surviving fish had a significantly lower mean movement per day than fish, which later either died or disappeared. This difference in behaviour was most pronounced 2 to 8 days after release. Predation by the otter Lutra lutra was probably the main cause of the observed mortality.
No reduction in neutral variability of mitochondrial and nuclear genes for a Lessepsian migrant, Upeneus moluccensis
Authors: Hassan M. , Bonhomme F.
Published: March 2005

Using nuclear (introns) and mitochondrial markers, two populations of the Lessepsian fish Upeneus moluccensis sampled from its original (Red Sea) and new habitat (Mediterranean Sea) were compared. No significant genetic difference was observed hence the passage through the Suez Canal does not seem to have affected the genetic diversity at the presumably neutral loci studied.
Ontogenic changes in the allometric scaling of the mass and length relationship in Sprattus sprattus
Authors: Peck M. A. , Clemmesen C. , Herrmann J.‐P.
Published: March 2005

An analysis of mass (M) and standard length (LS) data for larval, juvenile and adult sprat (Sprattus sprattus; Clupeidae) revealed marked changes in the allometric scaling factor (b in ). For sprat <44 mm LS, b was 5·0, whereas in larger juveniles and adults, b was c. 3·4 indicating a relatively protracted metamorphic period for this species.
The polarization of inner ear ciliary bundles from a scorpaeniform fish
Authors: Lovell J. M. , Findlay M. M. , Moate R. M. , Pilgrim D. A.
Published: March 2005

The polarization of ultrastructural ciliary bundles from hair cells in the inner ear of the sea scorpion Taurulus bubalis was studied using a scanning electron microscope, revealing arrays of ciliary bundles with diverse orientations on each of the sensory epithelia. Members of this order are known to produce sound, though results of this study show no significant variation from the standard receptor patterns found in the hearing system of many silent marine teleosts. This is the first time that the ultrastructure of T. bubalis has been studied, and this work presents a new set of polarization patterns, which provide anatomical information important in understanding electrophysiological aspects of fish hearing from an ecological perspective.
Human African trypanosomiasis: clinical presentation and immune response
Authors: Sternberg J. M.
Published: March 2005

Human African trypanosomiasis or sleeping sickness is caused by infection with two subspecies of the tsetse‐fly‐vectored haemoflagellate parasite Trypanosoma brucei. Historically, epidemic sleeping sickness has caused massive loss of life, and related animal diseases have had a crucial impact on development in sub‐Saharan Africa. After a period of moderately successful control during the mid‐part of the 20th century, sleeping sickness incidence is currently rising, and control is hampered by a combination of factors, including civil unrest and the possible development of drug resistance by the parasites. The prevailing view is that the disease is invariably fatal without anti‐trypanosomal drug treatment. However, there have also been intriguing reports of wide variations in disease severity as well as evidence of asymptomatic carriers of trypanosomes. These differences in the presentation of the disease will be discussed in the context of our knowledge of the immunology of trypanosomiasis. The impact of dysregulated inflammatory responses in both systemic and CNS pathology will be examined and the potential for host genotype variation in disease severity and control will be discussed.
Adaptive variation in coral geometry and the optimization of internal colony light climates
Authors: ANTHONY K. R. N. , HOOGENBOOM M. O. , CONNOLLY S. R.
Published: March 2005

The ability of photosynthetic organisms to adjust their light climate has high adaptive significance because irradiance can vary spatially by orders of magnitude. Using a plating (foliaceous) coral species (Turbinaria mesenterina), we tested the hypothesis that plasticity of colony geometry optimizes internal irradiance distributions.

We developed a two‐dimensional model to predict the internal irradiance distribution of a foliaceous colony as a function of its geometry. Field tests showed that the model explained 85% of the variation in irradiance within colonies ofT. mesenterinawith minimal bias.

Colony plate angle, plate spacing and range of tissue distributions into the colony were exponential functions of water depth. In shallow water plates tended to be nearly vertical, narrowly spaced, and had living tissue only near the growing edge of the plate. In deep water plates grew more horizontally, were more widely spaced, and had living tissue extending well into the colony interior. This pattern of phenotypic plasticity effectively evens out differences in within‐colony irradiances.

We compared within‐colony irradiance distributions across light habitats (depth), based on the observed variation in colony geometry with water depth. Despite fourfold differences in environmental irradiance, within‐colony irradiances had a common mode of 100–200 µmol m−2 s−1. This is near the hypothesized photosynthetic optimum defined by the upper limit of the subsaturation parameter (Ek) of the photosynthesis–irradiance curve.

Our study demonstrates that phenotypic plasticity of colony geometry is an important mechanism for regulating light capture during growth inT. mesenterina, and facilitates near‐optimal internal irradiances across a wide range of environmental light regimes.
Deriving a neutral model of species abundance from fundamental mechanisms of population dynamics
Authors: HE F.
Published: March 2005

Ecologists have long sought to derive assembly rules of ecological communities from the fundamental processes of population dynamics, but this goal has remained elusive. Neutral theory has reinvigorated the search by showing that patterns of relative species abundance closely resembling those actually observed arise under the assumption that, to a first approximation, all species are demographically identical on a per capita basis.

Here a neutral model is proposed to incorporate all four fundamental processes of population dynamics: birth, death, immigration and emigration. This symmetric model demonstrates that patterns of relative species abundance are fully derivable from these basic processes of population dynamics.

The theory derived extends the concept of community by showing that a continuum exists between large‐scale (‘metacommunity’) and small‐scale (‘local community’) processes, eliminating the artificial distinction between the two made by the current neutral theory and by the theory of island biogeography.

The population‐based species‐abundance model describes very well the observed patterns of relative species abundance of tropical trees, breeding birds in the USA, aphids at Rothamsted, UK, and estuarine fishes in the north‐east USA.

The study also notes that while species assemblages may be well described by the neutral processes of population dynamics, the inference of mechanisms from pattern fitting is not warranted because one‐to‐one relationships between generating mechanisms and community patterns usually do not exist, either in the neutral realm or in the niche world.
Mast cell accumulation and cytokine expression in the tight skin mouse model of scleroderma
Authors: Wang Hong‐Wei , Tedla Nicodemus , Hunt John E. , Wakefield Denis , McNeil H. Patrick
Published: March 2005

Abstract:  The tight skin (Tsk) mouse develops many pathological changes seen in human scleroderma, such as increased collagen content and mast cell density. Although associations between mast cell expansion and skin fibrosis have been reported, the mechanisms underlying mast cell accumulation remain unclear. In this study, we have measured the density of skin mast cells in Tsk mice and their normal littermates (pa/pa) of 4–36 weeks of age, and in the skin heterografted between Tsk and pa/pa mice. Cytokines related to mast cell differentiation, proliferation and migration were examined by using RNase protection assays. Skin mast cell density in Tsk mice was significantly increased from 12 weeks of age, compared to that in pa/pa mice. The expression of transforming growth factor‐β1 (TGF‐β1), and to a lesser extent, stem cell factor (SCF) and interleukin‐15 (IL‐15) mRNA was higher in Tsk mice, compared to that in control mice. Mast cell density was unchanged in Tsk skin grafted onto pa/pa hosts, but dramatically increased in pa/pa skin grafted onto Tsk hosts. This latter mast cell hyperplasia was associated with the increases in mRNA levels of TGF‐β1, SCF and IL‐15, whereas little change in cytokine levels was seen in heterografted Tsk skin. These results suggest that locally produced cytokines in Tsk skin influence mast cell accumulation in this animal model of human scleroderma.
Variation in the herb species response and the humus quality across a 200‐year chronosequence of beech and oak plantations in Belgium
Authors: Godefroid S. , Massant W. , Koedam N.
Published: March 2005

The present study aimed at exploring the long‐term impact of pure and mixed beech Fagus sylvatica and oak Quercus robur stands on the forest floor by documenting changes in the herb species’ behaviour and in humus index across a 200‐yr chronosequence of forest stands. The research was conducted in central Belgium, in a 4383 ha beech‐dominated forest. Analyses were carried out in stands which are replicated, of the same age, managed in the same way, and growing on the same soil type with the same land‐use history. The results of this study indicate that stand aging is an important determinant of herb species occurrence in the studied area. Most of the species studied show a different response to stand age in pure compared to mixed stands. Our results clearly show a decrease of the humus quality with age in pure stands (beech as well as oak). On the other hand, we found that mixing beech and oak maintained or improved the humus status along the chronosequence according to the proportion of each tree. So the addition of some oak to the beech made it possible to keep a constant quality of the humus. We found that, even if the understory tree species is very scarce, it may be sufficient to maintain the humus status on the long term. In the present study, a cover of 1% oak in a beech stand was sufficient to show an effect of the minor species on these soils. This pattern contrasts with the widespread idea that substantial effects of the minor tree species on soils might not develop if the ratio of major/minor species is low.
Gallery forest types and their environmental correlates in a Colombian savanna landscape
Authors: Veneklaas Erik J. , Fajardo Adriana , Obregon Sandra , Lozano Jaime
Published: March 2005

Savanna regions may contain significant areas of forest, usually in riparian environments. We described forest composition and quantified environmental variables for 80 plots in the watershed of the Yucao River (2550 km2), a tributary to the Meta River (Orinoco basin) in the eastern plains of Colombia. The total sampled area of 3.2 ha contained 147 tree species (110 genera and 45 families) with diameter at breast height >5 cm. The families represented by most species were Leguminosae (15 species), Arecaceae (11 species), Rubiaceae (9), Chrysobalanaceae (7), Euphorbiaceae (7), Melastomataceae (7) and Myrtaceae (7). Although most of the tree species have wide distribution ranges in humid neotropical forests, and few are endemic to the region, comparison with other neotropical forests suggests that the combination of taxa is characteristic for neotropical gallery forests. Cluster analysis allowed the definition of five forest types. They show important differences in a number of environmental variables, especially those related to inundation regimes and soil properties. Canonical correspondence analysis indicates good correlation of the first ordination axis with the size of the stream with which the forest is associated, the height to which the water rises during floods and variables related to soil fertility. The second ordination axis differentiates between soils with high or low water content in the dry season, high or low organic matter content and low or high bulk density. The results demonstrate the role of spatial variability and interactions of floodplain morphology, hydrological regime, and soil properties in structuring this important riparian community.
Compatible scales for progressive and additive MRI assessments of haemophilic arthropathy
Authors: Lundin B. , Babyn P. , Doria A. S. , Kilcoyne R. , Ljung R. , Miller S. , Nuss R. , Rivard G. E. , Pettersson H. ,   The International Prophylaxis Study Group
Published: March 2005

Summary.  The international MRI expert subgroup of the International Prophylaxis Study Group (IPSG) has developed a consensus for magnetic resonance imaging (MRI) scales for assessment of haemophilic arthropathy. A MRI scoring scheme including a 10 step progressive scale and a 20 step additive scale with identical definitions of mutual steps is presented. Using the progressive scale, effusion/haemarthrosis can correspond to progressive scores of 1, 2, or 3, and synovial hypertrophy and/or haemosiderin deposition to 4, 5, or 6. The progressive score can be 7 or 8 if there are subchondral cysts and/or surface erosions, and it is 9 or 10 if there is loss of cartilage. Using the additive scale, synovial hypertrophy contributes 1–3 points to the additive score and haemosiderin deposition contributes 1 point. For osteochondral changes, 16 statements are evaluated as to whether they are true or false, and each true statement contributes 1 point to the additive score. The use of these two compatible scales for progressive and additive MRI assessments can facilitate international comparison of data and enhance the accumulation of experience on MRI scoring of haemophilic arthropathy.
Use of a patient information system to audit the introduction of modified early warning scoring
Authors: Quarterman C. P. J. , Thomas A. N. , McKenna M. , McNamee R.
Published: March 2005

Modified early warning scoring (MEWS) uses abnormalities in routine observations to identify patients at risk of critical illness. Nurses recorded scores at or above the medical response score of 3 on a hospital clinical information system during the first year of introducing MEWS to 10 wards in a university hospital. A total of 619 triggers were recorded in 365 patients. Fifty‐nine required intensive care unit (ICU)/high dependency unit (HDU) care; 71 died. Survival was significantly worse for initial scores > 4 (35/104 patients died) than for scores 3–4 (P < 0.004). Multivariant analysis showed age (P < 0.001) and trigger score (P < 0.001) but not ward specialty (P = 0.1) predicted death. Mean ages of survivors and non‐survivors were 64 years (SD 18) and 74 years (SD 17), respectively. Addition of a score for age did not significantly increase the area under a receiver operator characteristic curve for the predictive value of MEWS scores. The study shows that increasing MEWS score is associated with worse outcome across a range of specialties and that nursing staff will use a patient information system to audit MEWS scores.
Temperature acclimation of photosynthesis in spinach leaves: analyses of photosynthetic components and temperature dependencies of photosynthetic partial reactions
Authors: YAMORI WATARU , NOGUCHI KO , TERASHIMA ICHIRO
Published: March 2005

Spinach (Spinacia oleracea) plants were grown under the day/night temperature regime of 15/10 °C (LT) or 30/25 °C (HT). The plants were also transferred from HT to LT when the sample leaves were at particular developmental stages (HL‐transfer). With fully mature leaves, the light‐saturated photosynthetic rate (A) at the ambient CO2 concentration (Ca) of 1500 µL L−1 (A1500) and the initial slope of A versus intercellular CO2 concentration (Ci) at low Ci region (IS) were obtained to assess capacities of RuBP regeneration and carboxylation. Photosynthetic components including Rubisco and cytochrome f (Cyt f) were also determined. The optimum temperatures for A at Ca of 360 µL L−1 (A360), A1500 and IS in HT leaves were 27, 36 and 24 °C, whereas those in LT leaves were 18, 30 and 18 °C. The optimum temperatures in HL‐transfer leaves approached those of LT leaves with the increase in the duration at LT. The shift in the optimum temperature was greater and quicker for IS than A1500. By the HL‐transfer, the maximum values of A1500 and IS also increased. The maximum A1500 and Cyt f content increased more promptly than IS and Rubisco content. Changes in the Cyt f/Rubisco ratio were reflected to those in the A1500/IS ratio. Taken together, photosynthetic acclimation to low temperature in spinach leaves was due not only to the change in the balance of the absolute rates of RuBP regeneration and carboxylation but also to the large change in the optimum temperature of RuBP carboxylation.
Nitrate, a signal relieving seed dormancy in Arabidopsis
Authors: ALBORESI A. , GESTIN C. , LEYDECKER M.‐T. , BEDU M. , MEYER C. , TRUONG H.‐N.
Published: March 2005

Nitrate is an important nitrogen source for plants, but also a signal molecule that controls various aspects of plant development. In the present study the role of nitrate on seed dormancy in Arabidopsis was investigated. The effects of either mutations affecting the Arabidopsis nitrate reductase genes or of different nitrate regimes of mother plants on the dormancy of the seeds produced were analysed. Altogether, data show that conditions favouring nitrate accumulation in mother plants and in seeds lead to a lower dormancy of seeds with little other morphological or biochemical differences. Analysis of germination during seed development indicated that nitrate does not prevent the onset of dormancy but rather its maintenance. The effect of an exogenous supply of nitrate on seed germination was tested: nitrate in contrast to glutamine or potassium chloride clearly stimulated the germination of dormant seeds. Data show, moreover, that the Arabidopsis dual affinity nitrate transporter NRT1.1 (CHL1) may be involved in conveying the nitrate signal into seeds. Thus, nitrate provided exogenously or by mother plants to the produced seeds, acts as a signal molecule favouring germination in Arabidopsis. This signalling may involve interaction with the abscisic acid or gibberellin pathway.
Colostrum management in calves: effects of drenching vs. bottle feeding
Authors: Kaske M. , Werner A. , Schuberth H.‐J. , Rehage J. , Kehler W.
Published: March 2005

The objective was to examine whether the administration of colostrum by a drencher is a safe method to achieve satisfying immunoglobulin concentrations in newborn Holstein Friesian (HF)‐calves. Twenty‐one calves were fed 1 h postnatum with 2 l colostrum from their dam using a nipple bottle (group I); 15 calves were drenched with 4 l colostrum from their dam 1 h postnatum (group II). Thereafter, all calves were fed milk replacer exclusively. Serum concentration of total immunoglobulin [analysed by Sandwich‐enzyme‐linked immunosorbent assay (ELISA)] 24 h postnatum was higher in drenched calves (25.2 g/l; 12.8/52.2; median and 10/90 percentiles) compared with bottle‐fed calves (14.1 g/l; 9.2/24.7). To characterize the kinetics of immunoglobulin absorption, 17 blood samples were taken frequently within 72 h postnatum using a jugular catheter in five calves fed 2 l colostrum by nipple bottle and five calves drenched with 4 l colostrum 1 h postnatum. A slightly delayed increase of serum immunoglobulin concentration (approximately 3 h) was obvious in drenched calves compared with bottle‐fed calves, but drenched calves reached significantly higher immunoglobulin concentrations compared with bottle‐fed calves. It is concluded that the proper application of colostrum by a drencher is a useful method for adequate colostral supply in newborn calves. The failure of the oesophageal groove reflex in drenched calves caused no clinical consequences.