bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of chiral ligands for asymmetric catalysis: From C
2
-symmetric P,P- and N,N-ligands to sterically and electronically nonsymmetrical P,N-ligands
Authors: Pfaltz Andreas , Drury William J.
Published: April 2004

For a long time, C
2
-symmetric ligands have dominated in asymmetric catalysis. More recently, nonsymmetrical modular P,N-ligands have been introduced. These ligands have been applied successfully in various metal-catalyzed reactions and, in many cases, have outperformed P,P- or N,N-ligands.
Two feeding-induced proteins from the male gonad trigger engorgement of the female tickAmblyomma hebraeum
Authors: Weiss Brian L. , Kaufman W. Reuben
Published: April 2004

Most female ixodid ticks, once mated, feed to repletion within 6–10 days. Previous studies indicate that an engorgement factor (EF), passed to the female during copulation, may be the stimulus for engorgement. Here, we show that extracts of the testis/vas deferens of fed (but not unfed) maleAmblyomma hebraeumcontain EF bioactivity when injected into the hemocoel of feeding virgins. We have produced recombinant proteins (recproteins) from 28 feeding-induced genes in the male gonad and have identified a recombinantA. hebraeumengorgement factor (recAhEF) among theserecproteins.recAhEF is a combination of two peptides,recAhEFα (16.1 kDa) andrecAhEFβ (11.6 kDa), neither of which has bioactivity on its own.recAhEF also stimulates salivary gland degeneration and partial development of the ovary, suggesting that it may be the same material as another male gonadal protein from this tick, male factor. We propose the name “voraxin” for the natural EF of ticks. When normal mated females were put on a rabbit immunized againstrecAhEF, 74% failed to feed beyond one-tenth the normal engorged weight within 14 days whereas all mated ticks put on a control rabbit engorged normally (mean duration of 8.8 ± 0.8 days). This result constitutes preliminary evidence that an anti-tick vaccine might be developed from voraxin.
Highly enantioselective epoxidation of styrenes: Implication of an electronic effect on the competition between spiro and planar transition states
Authors: Hickey Matthew , Goeddel David , Crane Zackary , Shi Yian
Published: April 2004

Asymmetric epoxidation of various styrenes using carbocyclic oxazolidinone-containing ketone 3 has been investigated. High enantioselectivity (89–93% enantiomeric excess) has been attained for this challenging class of alkenes. Mechanistic studies show that substituents on the ketone catalyst can have electronic influences on secondary orbital interactions, which affects the competition between spiro and planar transition states and, ultimately, enantioselectivity. The results described herein not only reveal the potential of chiral dioxirane catalyzed asymmetric epoxidation as a viable entry into this important class of olefins but also further enhance the understanding of the mechanistic aspects of chiral ketone-catalyzed asymmetric epoxidation.
Development of an efficient, scalable, aldolase-catalyzed process for enantioselective synthesis of statin intermediates
Authors: Greenberg William A. , Varvak Alexander , Hanson Sarah R. , Wong Kelvin , Huang Hongjun , Chen Pei , Burk Mark J.
Published: April 2004

A process is reported for efficient, enantioselective production of key intermediates for the common chiral side chain of statin-type cholesterol-lowering drugs such as Lipitor (atorvastatin) and Crestor (rosuvastatin). The process features a one-pot tandem aldol reaction catalyzed by a deoxyribose-5-phosphate aldolase (DERA) to form a 6-carbon intermediate with installation of two stereogenic centers from 2-carbon starting materials. An improvement of almost 400-fold in volumetric productivity relative to the published enzymatic reaction conditions has been achieved, resulting in a commercially attractive process that has been run on up to a 100-g scale in a single batch at a rate of 30.6 g/liter per h. Catalyst load has been improved by 10-fold as well, from 20 to 2.0 wt % DERA. These improvements were achieved by a combination of discovery from environmental DNA of DERAs with improved activity and reaction optimization to overcome substrate inhibition. The two stereogenic centers are set by DERA with enantiomeric excess at >99.9% and diastereomeric excess at 96.6%. In addition, down-stream chemical steps have been developed to convert the enzymatic product efficiently to versatile intermediates applicable to preparation of atorvastatin and rosuvastatin.
Receptor-mediated regulation of the TRPM7 channel through its endogenous protein kinase domain
Authors: Takezawa Ryuichi , Schmitz Carsten , Demeuse Philippe , Scharenberg Andrew M. , Penner Reinhold , Fleig Andrea
Published: April 2004

TRPM7 is a ubiquitously expressed and constitutively active divalent cation-selective ion channel, whose basal activity is regulated by intracellular levels of Mg
2+
and Mg·ATP. We have investigated receptor-mediated mechanisms that may actively regulate TRPM7 activity. We here report that TRPM7 currents are suppressed by intracellular GTPγS, suggesting the involvement of heterotrimeric G proteins. TRPM7 currents are also inhibited by stimulating endogenous muscarinic receptors, which is mediated by G
i
because the inhibitory effect is blunted by pertussis toxin. Conversely, stimulation of endogenous G
s
-coupled β-adrenergic receptors potentiates TRPM7 currents, whereas G
q
-coupled thrombin receptors have little effect. Consistent with the involvement of G
s
/G
i
in controlling adenylyl cyclase activity, elevations of intracellular cAMP levels enhance TRPM7 activity and prevent receptor-mediated modulation of TRPM7 activity by muscarinic and adrenergic agonists. This cAMP-dependent effect requires the functional integrity of both protein kinase A (PKA) and the endogenous kinase domain of TRPM7 because cAMP-mediated effects are abolished when treating cells with the PKA inhibitors H89 or KT5720 as well as in cells expressing phosphotransferase-deficient TRPM7 constructs. These mutant channels are also much less susceptible to GTPγS-mediated inhibition, suggesting that the main regulatory effect occurs through G
i
- and G
s
-mediated changes in cAMP. Taken together, our results demonstrate that TRPM7 activity is up- and down-regulated through its endogenous kinase in a cAMP- and PKA-dependent manner.
Mechanisms for activating Cu- and Zn-containing superoxide dismutase in the absence of the CCS Cu chaperone
Authors: Carroll Mark C. , Girouard Jody B. , Ulloa Janella L. , Subramaniam Jamuna R. , Wong Phillip C. , Valentine Joan Selverstone , Culotta Valeria Cizewski
Published: April 2004

The Cu- and Zn-containing superoxide dismutase 1 (SOD1) largely obtains Cuin vivoby means of the action of the Cu chaperone CCS. Yet, in the case of mammalian SOD1, a secondary pathway of activation is apparent. Specifically, when human SOD1 is expressed in either yeast or mammalian cells that are null for CCS, the SOD1 enzyme retains a certain degree of activity. This CCS-independent activity is evident with both wild-type and mutant variants of SOD1 that have been associated with familial amyotrophic lateral sclerosis. We demonstrate here that the CCS-independent activation of mammalian SOD1 involves glutathione, particularly the reduced form, or GSH. A role for glutathione in CCS-independent activation was seen with human SOD1 molecules that were expressed in either yeast cells or immortalized fibroblasts. Compared with mammalian SOD1, theSaccharomyces cerevisiaeenzyme cannot obtain Cu without CCSin vivo, and this total dependence on CCS involves the presence of dual prolines near the C terminus of the SOD1 polypeptide. Indeed, the insertion of such prolines into human SOD1 rendered this molecule refractory to CCS-independent activation. The possible implications of multiple pathways for SOD1 activation are discussed in the context of SOD1 evolutionary biology and familial amyotrophic lateral sclerosis.
Parallel genetic basis for repeated evolution of armor loss in Alaskan threespine stickleback populations
Authors: Cresko William A. , Amores Angel , Wilson Catherine , Murphy Joy , Currey Mark , Phillips Patrick , Bell Michael A. , Kimmel Charles B. , Postlethwait John H.
Published: April 2004

Most adaptation is thought to occur through the fixation of numerous alleles at many different loci. Consequently, the independent evolution of similar phenotypes is predicted to occur through different genetic mechanisms. The genetic basis of adaptation is still largely unknown, however, and it is unclear whether adaptation to new environments utilizes ubiquitous small-effect polygenic variation or large-effect alleles at a small number of loci. To address this question, we examined the genetic basis of bony armor loss in three freshwater populations of Alaskan threespine stickleback,Gasterosteus aculeatus, that evolved from fully armored anadromous populations in the last 14,000 years. Crosses between complete-armor and low-armor populations revealed that a single Mendelian factor governed the formation of all but the most anterior lateral plates, and another independently segregating factor largely determined pelvic armor. Genetic mapping localized the Mendelian genes to different chromosomal regions, and crosses among these same three widely separated populations showed that both bony plates and pelvic armor failed to fully complement, implicating the same Mendelian armor reduction genes. Thus, rapid and repeated armor loss in Alaskan stickleback populations appears to be occurring through the fixation of large-effect variants in the same genes.
Orchestration of cooperative events in DNA synthesis and repair mechanism unraveled by transition path sampling of DNA polymerase β's closing
Authors: Radhakrishnan Ravi , Schlick Tamar
Published: April 2004

Our application of transition path sampling to a complex biomolecular system in explicit solvent, the closing transition of DNA polymerase β, unravels atomic and energetic details of the conformational change that precedes the chemical reaction of nucleotide incorporation. The computed reaction profile offers detailed mechanistic insights into, as well as kinetic information on, the complex process essential for DNA synthesis and repair. The five identified transition states extend available experimental and modeling data by revealing highly cooperative dynamics and critical roles of key residues (Arg-258, Phe-272, Asp-192, and Tyr-271) in the enzyme's function. The collective cascade of these sequential conformational changes brings the DNA/DNA polymerase β system to a state nearly competent for the chemical reaction and suggests how subtle residue motions and conformational rate-limiting steps affect reaction efficiency and fidelity; this complex system of checks and balances directs the system to the chemical reaction and likely helps the enzyme discriminate the correct from the incorrect incoming nucleotide. Together with the chemical reaction, these conformational features may be central to the dual nature of polymerases, requiring specificity (for correct nucleotide selection) as well as versatility (to accommodate different templates at every step) to maintain overall fidelity. Besides leading to these biological findings, our developed protocols open the door to other applications of transition path sampling to long-time, large-scale biomolecular reactions.
Cell-interdependent cisplatin killing by Ku/DNA-dependent protein kinase signaling transduced through gap junctions
Authors: Jensen Ryan , Glazer Peter M.
Published: April 2004

Cisplatin is one of the most widely used cancer chemotherapy agents, but its mechanism of action is not fully understood. Current models suggest that cell killing by cisplatin occurs in a cell-autonomous manner by means of formation of platinum-DNA adducts that, if not removed by DNA repair, block transcription and replication. Here, we show that there is a separate cell-interdependent pathway of cisplatin killing in which damaged cells can transmit a death signal to neighboring cells. This signal is produced within the damaged cell by the kinase function of the Ku70, Ku80, and DNA-dependent protein kinase complex and is conveyed to the recipient cell by direct cell-to-cell communication through gap junctions. These findings suggest that DNA-dependent protein kinase activity and gap junction expression in human cancers may influence the clinical response to cisplatin. In addition, strategies to manipulate these cellular components in conjunction with cisplatin treatment may provide new approaches to cancer therapy.
Testing protein-folding simulations by experiment: B domain of protein A
Authors: Sato Satoshi , Religa Tomasz L. , Daggett Valerie , Fersht Alan R.
Published: April 2004

We have assessed the published predictions of the pathway of folding of the B domain of protein A, the pathway most studied by computer simulation. We analyzed the transition state for folding of the three-helix bundle protein, by using experimental Φ values on some 70 suitable mutants. Surprisingly, the third helix, which has the most stable α-helical structure as a peptide fragment, is poorly formed in the transition state, especially at its C terminus. The protein folds around a nearly fully formed central helix, which is stabilized by extensive hydrophobic side chain interactions. The turn connecting the poorly structured first helix to the central helix is unstructured, but the turn connecting the central helix to the third is in the process of being formed as the N-terminal region of the third helix begins to coalesce. The transition state is inconsistent with a classical framework mechanism and is closer to nucleation–condensation. None of the published atomistic simulations are fully consistent with the experimental picture although many capture important features. There is a continuing need for combining simulation with experiment to describe folding pathways, and of continued testing to improve predictive methods.
Two RNA polymerase complexes from vesicular stomatitis virus-infected cells that carry out transcription and replication of genome RNA
Authors: Qanungo Kaustubha R. , Shaji Daniel , Mathur Manjula , Banerjee Amiya K.
Published: April 2004

By immunoaffinity column chromatography, we have purified two RNA polymerase complexes, the transcriptase and replicase, from vesicular stomatitis virus-infected baby hamster kidney cells. The transcriptase is a multiprotein complex, containing the virus-encoded RNA polymerase L and P proteins, and two cellular proteins, translation elongation factor-1α and heat-shock protein 60. In addition, the complex contains a submolar amount of cellular mRNA cap guanylyltransferase. The replicase, on the other hand, is a complex containing the viral proteins, L, P, and the nucleocapsid (N), but lacking elongation factor-1α, heat-shock protein 60, and guanylyltransferase. The transcriptase complex synthesizes capped mRNAs and initiates transcription at the first gene (N) start site, whereas the replicase complex initiates RNA synthesis at the precise 3′ end of the genome RNA and synthesizes encapsidated replication products in the presence of the N–P complex. We propose that two RNA polymerase complexes that differ in their content of virally and host-encoded proteins are separately responsible for transcription and replication of vesicular stomatitis virus genome RNA.
Fluoxetine and norfluoxetine stereospecifically facilitate pentobarbital sedation by increasing neurosteroids
Authors: Pinna Graziano , Costa Erminio , Guidotti Alessandro
Published: April 2004

Mice housed in social isolation exhibit a decreased response to γ-aminobutyric acid-mimetic drugs [i.e., pentobarbital (PTB)] associated with a down-regulation of telencephalic allopregnanolone (Allo) levels. In these mice, the PTB-induced loss of righting reflex is greatly reduced. Fluoxetine (FLX) and norfluoxetine (NFLX) stereospecifically reverse the effect of social isolation on the PTB-induced loss of righting reflex and on the decrease of telencephalic Allo content. The S-isomers of FLX and NFLX are 2- and 7-fold more potent, respectively, than their respective R-isomers. The EC
50
s of FLX and NFLX required to normalize brain Allo content and PTB action are 10–50 times lower than the IC
50
s required for selective serotonin reuptake inhibitor activity. We conclude that normalization of PTB action elicited by the S-isomers of FLX and NFLX is related to the reversal of the down-regulation of brain Allo content and is independent of selective serotonin reuptake inhibitor activity.
Comparative analysis of gene expression among low G+C gram-positive genomes
Authors: Karlin Samuel , Theriot Julie , Mrázek Jan
Published: April 2004

We present a comparative analysis of predicted highly expressed (PHX) genes in the low G+C Gram-positive genomes of
Bacillus subtilis
,
Bacillus halodurans
,
Listeria monocytogenes
,
Listeria innocua
,
Lactococcus lactis
,
Streptococcus pyogenes
,
Streptococcus pneumoniae
,
Staphylococcus aureus
,
Clostridium acetobutylicum
, and
Clostridium perfringens
. Most enzymes acting in glycolysis and fermentation pathways are PHX in these genomes, but not those involved in the TCA cycle and respiration, suggesting that these organisms have predominantly adapted to grow rapidly in an anaerobic environment. Only
B. subtilis
and
B. halodurans
have several TCA cycle PHX genes, whereas the TCA pathway is entirely missing from the metabolic repertoire of the two
Streptococcus
species and is incomplete in
Listeria
,
Lactococcus
, and
Clostridium
. Pyruvate-formate lyase, an enzyme critical in mixed acid fermentation, is among the highest PHX genes in all these genomes except for
C. acetobutylicum
(not PHX), and
B. subtilis
, and
B. halodurans
(missing). Pyruvate-formate lyase is also prominently PHX in enteric γ-proteobacteria, but not in other prokaryotes. Phosphotransferase system genes are generally PHX with selection of different substrates in different genomes. The various substrate specificities among phosphotransferase systems in different genomes apparently reflect on differences in habitat, lifestyle, and nutrient sources.
Expression of MeCP2 in postmitotic neurons rescues Rett syndrome in mice
Authors: Luikenhuis Sandra , Giacometti Emanuela , Beard Caroline F. , Jaenisch Rudolf
Published: April 2004

Mutations in
MECP2
are the cause of Rett syndrome (RTT) in humans, a neurodevelopmental disorder that affects mainly girls. MeCP2 is a protein that binds CpG dinucleotides and is thought to act as a global transcriptional repressor. It is highly expressed in neurons, but not in glia, of the postnatal brain. The timing of MeCP2 activation correlates with the maturation of the central nervous system, and recent reports suggest that MeCP2 may be involved in the formation of synaptic contacts and may function in activity-dependent neuronal gene expression. Deletion or targeted mutation of
Mecp2
in mice leads to a Rett-like phenotype. Selective mutation of
Mecp2
in postnatal neurons leads to a similar, although delayed, phenotype, suggesting that MeCP2 plays a role in postmitotic neurons. Here we test the hypothesis that the symptoms of RTT are exclusively caused by a neuronal MeCP2 deficiency by placing
Mecp2
expression under the control of a neuron-specific promoter. Expression of the
Mecp2
transgene in postmitotic neurons resulted in symptoms of severe motor dysfunction. Transgene expression in
Mecp2
mutant mice, however, rescued the RTT phenotype.
Geographers and ‘globalization’: (yet) another missed boat?
Authors: Dicken Peter
Published: April 2004

Over the years, geographers have developed a disturbing – even dysfunctional – habit of missing out on important intellectual and politically significant debates, even those in which geographers would seem to have a major role to play. The syndrome of processes currently bundled together within the term ‘globalization’ is intrinsically geographical, as are the outcomes of such processes. Yet, once again, it seems, we are not, as a discipline, centrally involved in what are clearly very ‘big issues’ indeed. The purpose of this paper is to explore, in the context of ongoing globalization debates, the bases of this undesirable situation and to consider what might be done to redress it in ways that could both enhance intra‐ and interdisciplinarity and also make a contribution towards building a better world.
Social capital and poverty of the wage‐labour class: problems with the social capital theory
Authors: Das Raju J
Published: April 2004

Social capital, understood as norms of reciprocity and associational life, is supposed to provide a bottom‐up approach to poverty alleviation world‐wide. The World Bank says that social capital is a necessary condition for long‐term development and that social capital is the capital of the poor. This paper will argue that much of the literature is too sanguine of the benefits of social capital for the poor. It is, of course, important to look at the extent to which social capital can help the poor. But how the conditions of the poor people can also affect their social capital is equally important to examine, and this has often been neglected by many scholars who have been busy to prove that social capital is a new paradigm of development. Based on qualitative interviews in two rural areas in Orissa, eastern India, this paper seeks to examine whether and to what extent poor people of the daily wage labour class benefit from their social capital. It then goes on to unpack the mechanisms in which the economic‐political conditions under which poor people live and the spatiality of these conditions affect the production of social capital. By seeking to unpack the dialectical relation between social capital and poverty, the paper aims at problematizing the overly optimistic claims about social capital. It shows that it is untenable to posit social capital as an independent variable and poverty as a dependent variable because the economic‐political conditions of poor people have an enormous constraining effect on social capital itself and its supposed material benefits for the poor.
Unruly topographies: unemployment, citizenship and land settlement in inter‐war Wales
Authors: Linehan Denis , Gruffudd Pyrs
Published: April 2004

Between 1934 and 1939, over 5000 people, mainly ex‐miners and their families, were settled in government‐owned land settlements in England and Wales. This policy emerged as a response to mass unemployment, and complemented other schemes for the unemployed developed by the inter‐war National Government. This paper will consider the geographical conditions that were imagined, realized and contested in these settlements. Acknowledging the hybrid and liminal nature of these spaces, the paper mobilizes new work in cultural and historical geography and draws out the heterotopic potential of the settlement programme.
Class and space: social segregation in Japanese cities
Authors: Fielding Anthony J
Published: April 2004

It has become increasingly common to play down the ‘place stratification’ of Japanese cities, and to emphasize their lack of social class segregation. Demonstrating that the Japanese city lacks a social geography in this respect conforms to, and serves to advance, the view that Japan has produced a capitalist form of development that avoids many of the inequalities and social ills characteristic of other advanced capitalist societies (e.g. no ‘inner city’ problems). But do the social geographies of Japanese cities really conform to this picture of Japanese society? This issue is explored with the help of a new analysis of the occupational class geography of the city of Kyoto.
Where is Helvellyn? Fuzziness of multi‐scale landscape morphometry
Authors: Fisher Peter , Wood Jo , Cheng Tao
Published: April 2004

The landscape in which people live is made up of many features, which are named and have importance for cultural reasons. Prominent among these are the naming of upland features such as mountains, but mountains are an enigmatic phenomenon which do not bear precise and repeatable definition. They have a vague spatial extent, and recent research has modelled such classes as spatial fuzzy sets. We take a specifically multi‐resolution approach to the definition of the fuzzy set membership of morphometric classes of landscape. We explore this idea with respect to the identification of culturally recognized landscape features of the English Lake District. Discussion focuses on peaks and passes, and the results show that the landscape elements identified in the analysis correspond to well‐known landmarks included in a place name database for the area, although many more are found in the analysis than are named in the available database. Further analysis shows that a richer interrogation of the landscape can be achieved with Geographical Information Systems when using this method than using standard approaches.
Competition between domestic livestock and wild bharal Pseudois nayaur in the Indian Trans‐Himalaya
Authors: Mishra Charudutt , Van Wieren Sipke E. , Ketner Pieter , Heitkönig Ignas M. A. , Prins Herbert H. T.
Published: April 2004

The issue of competition between livestock and wild herbivores has remained contentious. We studied the diets and population structures of the mountain ungulate bharal Pseudois nayaur and seven species of livestock to evaluate whether or not they compete for forage. The study was conducted in the high altitude Spiti Valley, Indian Trans‐Himalaya.

We compared resource (forage) availability and bharal population structures between rangelands differing in livestock density. Forage availability was estimated by clipping the standing graminoid biomass in sample plots. Livestock and bharal population structures were quantified through annual censuses. Seasonal diets of livestock were studied by direct observations, while those of bharal were quantified through feeding signs on vegetation.

We found that livestock grazing causes a significant reduction in the standing crop of forage. Graminoid availability per unit livestock biomass was three times greater in a moderately grazed rangeland compared with an intensively grazed one.

There was considerable diet overlap among the herbivore species. In summer, bharal, yak Bos grunniens, horse Equus caballus, cow Bos indicus, and dzomo (yak–cow hybrids) fed predominantly on graminoids, while donkey E. asinus, sheep Ovis aries, and goat Capra hircus, consumed both graminoids and herbs. The summer diet of bharal was a subset of the diets of three livestock species. In winter, depleted graminoid availability caused bharal, yak and horse to consume relatively more herbs, while the remaining livestock species fed predominantly on graminoids. Diet overlap was less in winter but, in both seasons, all important forage species in the bharal diet were consumed in substantial amounts by one or more species of livestock.

Comparison of the population structures of bharal between two rangelands differing in livestock density by c. 30% yielded evidence of resource competition. In the intensively grazed rangeland, bharal density was 63% lower, and bharal population showed poorer performance (lower young : adult female ratios).

Synthesis and applications. High diet overlap between livestock and bharal, together with density‐dependent forage limitation, results in resource competition and a decline in bharal density. Under the present conditions of high livestock density and supplemental feeding, restricting livestock numbers and creating livestock‐free areas are necessary measures for conserving Trans‐Himalayan wild herbivores. Mediating competitive effects on bharal through supplemental feeding is not a feasible option.
The dynamics of hunted Icelandic goose populations: a reassessment of the evidence
Authors: Frederiksen Morten , Hearn Richard D. , Mitchell Carl , Sigfússon Arnór , Swann Robert L. , Fox Anthony D.
Published: April 2004

Migratory geese are dominant terrestrial herbivores in Arctic and north temperate regions. They are important quarry species and also conflict with agricultural interests through winter foraging. We investigated the dynamics of the populations of greylag Anser anser and pink‐footed Anser brachyrhynchus geese that breed in Iceland and winter in Britain.

We estimated seasonal and annual survival of both populations based on colour‐ringing programmes in Iceland 1996–2000 and in Britain since 1987. We used these results, along with hunting bag statistics from Iceland, in a set of models to assess the British autumn counts as well as the impact of hunting.

After a rapid increase, the pink‐footed goose counts stabilized after 1992 at around 230 000. The greylag goose counts increased slowly to c. 100 000 around 1990 and then declined to around 80 000. Both populations showed stable counts from 1996 to 2000, when the proportion of young recorded in autumn was 17·5% for greylag geese and 18·2% for pink‐footed geese. Hunting bag statistics have been compiled since 1995 in Iceland; during 1996–2000, means of 36 608 greylag geese and 13 991 pink‐footed geese were reported shot annually.

Mean annual adult and first‐year survival estimates were 0·727 and 0·472 for greylag geese, and 0·814 and 0·394 for pink‐footed geese. The lower survival of juvenile pink‐footed geese was probably due to higher natural mortality, whereas the generally lower survival of greylag geese could be explained by higher hunting pressure.

Simple modelling showed that the results from autumn surveys and bag statistics were incompatible for greylag geese. For the population to remain stable with the estimated survival rate, the proportion of juveniles in autumn must be 30%. We suggest that problems in separating juveniles from adults in October–November caused the lower proportion of juveniles recorded. Also, the number of greylag geese counted in autumn and the number reported shot in Iceland cannot both be correct; the bag statistics imply a population twice as large as the number counted. Large numbers of greylag geese may winter in areas not covered by the autumn census, but overreporting of the hunting bag may also have occurred. No such discrepancies were found for pink‐footed geese.

Synthesis and applications. We recommend that a stratified sampling programme be established for estimating the size and age composition of both goose species. The age composition of greylag geese can profitably be studied in Iceland in August, when juveniles are easily recognizable. Ringing should be continued as a tool for monitoring survival, and a hunting bag survey should be implemented in Britain. In general, the reliability of population surveys should always be tested with independent data.
Reproductive success of hatchery‐produced and wild‐born brown trout in an experimental stream
Authors: Dannewitz Johan , Petersson Erik , Dahl Jonas , Prestegaard Tore , Löf Anna‐Carin , Järvi Torbjörn
Published: April 2004

Although releases of hatchery‐produced salmonids to support conspecific wild populations have increased dramatically during recent decades, little information is available about the performance in the wild of hatchery fish and their offspring. Important factors determining the success and genetic outcomes of supportive breeding programmes include (i) the relative reproductive success of released hatchery fish in the wild, and (ii) the extent to which the propagation affects the variance in reproductive success in the population as a whole.

We performed two field experiments on brown trout Salmo trutta from the River Dalälven in Sweden, where we examined reproductive success in an experimental stream. In experiment 1 we compared reproductive success between trout from a seventh‐generation hatchery stock of native origin and wild‐born trout from the river. In experiment 2, we compared reproductive success between seventh‐generation hatchery trout and hatchery‐reared trout derived from wild‐born parents. Individual reproductive success, based on the number of offspring assigned using microsatellite markers, was assessed on three occasions after reproduction: immediately after hatching and after the first and second growth seasons.

In experiment 1 there were no significant differences in reproductive success between seventh‐generation hatchery trout and wild‐born trout. In experiment 2, males from wild‐born parents were more successful than males from the seventh‐generation hatchery stock, but this difference was not observed among females.

There was some evidence for a positive association between body size and reproductive success among females but not males. For males, the number of mates was significantly associated with reproductive success, but this relationship was not evident among females.

The variance in reproductive success was pronounced in both experiments, yielding estimates of the ratio between the genetically effective size and the census size of our experimental populations ranging from 0·12 to 0·59.

Synthesis and applications. Our results suggest that the reproductive success in the wild of hatchery‐produced and wild‐born trout with a common genetic background may be rather similar. These findings, in combination with the pronounced variance in reproductive success observed among breeders, indicate that supportive breeding can be managed to increase not only the census but also the genetically effective size of small, endangered salmonid populations. However, to minimize negative effects of hatchery selection, it is important to give priority to the restoration of natural habitats and thereby increase the reproductive output from individuals in the wild.
A quantitative approach to conservation planning: using resource selection functions to map the distribution of mountain caribou at multiple spatial scales
Authors: Johnson Chris J. , Seip Dale R. , Boyce Mark S.
Published: April 2004

Visualizing the distribution of rare or threatened species is necessary for effective implementation of conservation initiatives. Generalized linear models and geographical information systems (GIS) are now powerful tools for conservation planning, but issues of data availability, scale and model extrapolation complicate some applications.

Mountain caribou are an endangered ecotype of woodland caribouRangifer tarandus caribouthat occurs across central and southern British Columbia, Canada. Currently, conservation professionals use coarse small‐scale maps of important habitats to manage forest harvesting and human access across the northern extent of mountain caribou range. These maps were produced before the advent of readily available digital spatial information and are based on expert opinion and limited empirical data.

With the purpose of refining existing maps, we used survey results, radio‐telemetry locations and GIS data to construct resource selection functions (RSF) that quantified the habitat affinities and predicted the relative probability of occurrence of mountain caribou at two spatial scales. At the scale of the patch, the most parsimonious RSF model consisted of covariates for vegetation and aptly predicted the occurrence of caribou across low‐ to mid‐elevation habitats, but performed poorly across steep alpine terrain. At the landscape scale, a model containing Gaussian terms for elevation and slope was effective at predicting the broader distribution of caribou.

We produced a map consisting of the product of the relative probabilities of the patch and landscape RSF. The final map represented the relative probability of occurrence of caribou in vegetative patches weighted by the relative probability of occurrence across the larger study area. We found strong agreement between current definitions of important caribou habitats developed from expert opinion and RSF‐based maps generated from empirical data.

Synthesis and applications. Both expert opinion and RSF‐based approaches offer unique advantages for conservation mapping. Interpretability of results, documentation and repeatability of methods and data, estimates of precision and costs should all be considered when evaluating a technique. We argue that for some species and geographical locations, RSF is a superior technique, but expert opinion should play a role in model development and interpretation.
Human disturbance: people as predation‐free predators?
Authors: Beale Colin M. , Monaghan Pat
Published: April 2004

Human disturbance has been associated with declines in breeding success in numerous species and is of general concern to conservationists. However, the current framework for predicting and minimizing disturbance effects is weak and there is considerable uncertainty about why animals are disturbed by people in the first place.

We developed a behavioural model of perceived predation risk as a framework for understanding the effects of disturbance on cliff‐nesting birds. This encompassed the concept that the effects of disturbance should increase with increasing numbers of visitors, and decrease with distance from the nest, an insight ignored in current conservation practice.

The predictions of this model were tested using field data on nesting success in two species of seabird, kittiwake Rissa tridactyla and guillemot Uria aalge. Statistical models of nesting success in both species suggested that perceived predation risk is a good predictor of the effects of disturbance.

Synthesis and applications. Our findings suggest that fixed set‐back distances and buffer zones are likely to be inappropriate conservation measures in situations where the numbers of visitors to wildlife areas fluctuates spatially and temporally, as is generally the case. In managing access to wildlife areas there is a need to ensure that larger parties of visitors are kept further away from the nesting areas of vulnerable species or that set‐back distances are determined for the largest party likely to visit the site.
Removing GPS collar bias in habitat selection studies
Authors: Frair Jacqueline L. , Nielsen Scott E. , Merrill Evelyn H. , Lele Subhash R. , Boyce Mark S. , Munro Robin H. M. , Stenhouse Gordon B. , Beyer Hawthorne L.
Published: April 2004

Compared to traditional radio‐collars, global positioning system (GPS) collars provide finer spatial resolution and collect locations across a broader range of spatial and temporal conditions. However, data from GPS collars are biased because vegetation and terrain interfere with the satellite signals necessary to acquire a location. Analyses of habitat selection generally proceed without correcting for this known sampling bias. We documented the effects of bias in resource selection functions (RSF) and compared the effectiveness of two bias‐correction techniques.

The effects of environmental conditions on the probability of a GPS collar collecting a location were modelled for three brands of collar using data collected in 24‐h trials at 194 test locations. The best‐supported model was used to create GPS‐biased data from unbiased animal locations. These data were used to assess the effects of bias given data losses in the range of 10–40% at both 1‐ and 6‐h sampling intensities. We compared the sign, value and significance of coefficients derived using biased and unbiased data.

With 6‐h locations we observed type II error rates of 30–40% given as little as a 10% data loss. Biased data also produced coefficients that were significantly more negative than unbiased estimates. Increasing the sampling intensity from 6‐ to 1‐h locations eliminated type II errors but increased the magnitude of coefficient bias. No type I errors or changes in sign were observed.

We applied sample weighting and iterative simulation given a 30% data loss. For a biased vegetation type, simulation reduced more type II errors than weighting, most probably because the original sample size was re‐established. However, selection for areas near trails, which was influenced by a biased vegetation type, showed fewer type II errors after weighting existing animal locations than after simulation. Both techniques corrected 100% and ≥ 80% of the biased coefficients at the 6‐ and 1‐h sampling intensities, respectively.

Synthesis and applications. This study demonstrates that GPS error is predictable and biases the coefficients of resource selection models dependant upon the GPS sampling intensity and the level of data loss. We provide effective alternatives for correcting bias and discuss applying corrections under different sampling designs.
ORIGINAL PAPER. Relative values of the interventions of diversion and improved donor‐arm disinfection to reduce the bacterial risk from blood transfusion
Authors: McDonald C. P. , Roy A. , Mahajan P. , Smith R. , Charlett A. , Barbara J. A. J.
Published: April 2004

Background and Objectives  The aim of this study was to demonstrate the efficiency of diverting the initial 20‐ml donation from the collection bag and of an improved donor‐arm disinfection procedure in reducing bacterial contamination in blood.

Materials and Methods  Donations were collected in bags specially manufactured for the study. These bags incorporated two satellite pouches into each of which 20 ml of blood was collected. Blood initially flowed into sample pouch P1, representing a diversion pouch. Pouch P2 was then filled with 20 ml of blood, which allowed us to sample the collection bag after diversion was complete. Blood then flowed into the standard collection bag. The contents of the pouches were aerobically and anaerobically cultured on the BacT/ALERT automated culture system for 7 days. Two procedures were investigated in the study (each involving 1409 blood donations): one analysed the current disinfection procedure; and the other analysed an improved donor‐arm disinfection procedure.

Results  The use of diversion alone resulted in a 47% reduction in contamination, and improved donor‐arm disinfection alone resulted in a 57% reduction in contamination. Diversion plus improved donor‐arm disinfection produced a predicted 77% reduction in contamination.

Conclusions  The study validates diversion and an improved donor‐arm disinfection procedure. In combination, these two interventions produced a substantial reduction in contamination. These procedures are to be introduced by the English National Blood Service to enhance the safety of the blood supply.
First report of human immunodeficiency virus transmission via an RNA‐screened blood donation
Authors: Delwart E. L. , Kalmin N. D. , Jones T. S. , Ladd D. J. , Foley B. , Tobler L. H. , Tsui R. C. P. , Busch M. P.
Published: April 2004

Background and Objectives  Blood banks in the USA have recently introduced minipool nucleic acid amplification testing (MP‐NAT) of blood products to reduce the transmission of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) by transfusions. However, MP‐NAT is limited in its ability to detect preseroconversion samples with very low viral RNA loads.

Materials and Methods  To determine whether a red blood cell unit, from an MP‐NAT‐negative donation, transmitted HIV when transfused to a patient, we compared the viral sequences from the blood donor and recipient. The implicated donation was also tested by commercially available NAT assays at a range of dilution factors to determine whether the infectious unit could have been detected using individual‐donation NAT (ID‐NAT).

Results  Phylogenetic linkage of HIV sequences in the blood donor and recipient confirmed the transmission of HIV by blood transfusion, the first such case identified since introduction of MP‐NAT screening in 1999. Viral RNA was reliably detected by ID‐NAT, but only inconsistently detected by MP‐NAT.

Conclusions  Even following the introduction of MP‐NAT, a preseroconversion donation with a viral load of ≤ 150 copies of RNA/ml went undetected and resulted in an HIV transmission. Implementation of ID‐NAT will further reduce such rare transmissions, but at a considerable cost per infectious unit interdicted.
Impact of seeding rate on annual ryegrass performance
Authors: Venuto B. C. , Redfearn D. D. , Pitman W. D. , Alison M. W.
Published: April 2004

Annual ryegrass (Lolium multiflorum Lam.) is a primary forage resource for livestock producers throughout the south‐eastern USA during the winter‐growing season. It is important for livestock producers to begin grazing annual ryegrass as early as possible and any management practices maximizing early season production could be beneficial. To assess the impact of seeding rate on subsequent yield, yield distribution, quality, seedling density, and end‐of‐season plant and tiller density, a 2‐year study was initiated at four locations in Louisiana. Three annual ryegrass cultivars, varying in seed size, were established at four seeding rates based on pure live seed (PLS) rates of 400, 800, 1200 and 1600 PLS m−2. There was no advantage in total yield from increasing seeding rates beyond 800 PLS m−2. However, first‐harvest yields increased from 360 to 930 kg dry matter (DM) ha−1 as seeding rate increased from 400 to 1600 PLS m−2. Crude protein and neutral‐detergent fibre concentrations, and in vitro DM digestibility, were not affected by seeding rate. Seedling density and end‐of‐season plant numbers increased as seeding rate increased. However, stems per plant decreased as seeding rate increased, indicating compensatory tillering for the reduced plant numbers observed at the lower seeding rates. These results indicate first‐harvest yield can be increased by planting at higher seeding rates but total yields are not increased.
The nutritive value of Prangos ferulacea
Authors: Coşkun B. , Gülşen N. , Umucalılar H. D.
Published: April 2004

This study was conducted to determine the chemical composition and nutritive value of Prangos ferulacea, a plant found in the Mediterranean and Middle‐east regions, where it is used as animal fodder. Samples of mature plants were collected from S.E. Turkey. Metabolizable energy (ME) values were estimated from in vitro gas production measurements and from chemical composition. ME concentrations of the whole plant, leaves and stems were estimated to be 12·2, 11·9 and 12·7 MJ kg−1 dry matter (DM) respectively, which compares favourably with high‐quality forages commonly used in ruminant feeding. The DM degradability of the whole plant, leaves and stems increased up until 48 h of in situ incubation, 866, 915 and 784 g kg−1 DM respectively, but changed little between 48 and 72 h. In vitro DM and organic matter digestibility of the whole plant, leaves and stems were 0·769 and 0·806, 0·773 and 0·790, and 0·740 and 0·840 respectively. The results show that P. ferulacea may be regarded as a high‐energy forage, but further research is needed on its intake characteristics and the levels of animal performance that can be achieved from its inclusion in the diet.
Growth and chemical composition of wild oat (Avena fatua) under Mediterranean conditions
Authors: El‐Shatnawi M. K. J. , Saoub H. M. , Haddad N. I.
Published: April 2004

Wild oat (Avena fatua) is an annual cool‐season species that grows in areas with a Mediterranean climate and has potential as a forage source in Jordan. A field experiment was conducted during the growing seasons of 1999–2000 and 2000–2001 under sub‐humid Mediterranean conditions at Samta in the Ajloun Mountains, Jordan. Data on seasonal herbage mass, morphology and chemical composition of wild oat were collected at 60, 80, 100, 120 and 140 days after emergence.

Plant height increased rapidly beyond 100 days after emergence. The increase in herbage mass of dry matter was gradual and peaked at 140 days after emergence. The lowest concentration of crude fibre was at 60 and 80 days after emergence, with a range of 201–263 g kg−1 DM. Crude fibre concentrations (610–630 g kg−1 DM) peaked at 140 days after emergence (maturity). In contrast to concentrations of crude fibre, concentrations of crude protein decreased gradually with age. The calcium and phosphorus concentrations were sufficient to meet the maintenance requirements of ewes.