bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of animal studies in supporting human assisted reproductive technology
Authors: Bavister Barry
Published: December 2006

Although average success rates of human IVF have increased progressively during the past two decades, the efficiency of this technique, based on each embryo produced or transferred, is still low. High success rates are usually achieved by transferring several embryos to the patient, which is often associated with multiple pregnancies. The quality of in vitro produced embryos is a major area that needs attention. Because there is no in vivo database for human embryos, the properties of normal embryos are not known, and so it is difficult to know how to improve quality and viability. In addition, selection of the most viable embryos for transfer is a rather subjective process. The origins of human assisted reproductive technology (ART) are based on animal ART; however, the two areas of research (animal and human ART) appear to have become disconnected. Re-examination of progress in animal ART could help improve human embryo quality and thereby assist efforts to sustain high pregnancy rates with only one or two embryos transferred. Some key areas in which animal ART can help guide progress in human ART are discussed.
Applications of emerging technologies to the study and conservation of threatened and endangered species
Authors: Pukazhenthi Budhan , Comizzoli Pierre , Travis Alexander J. , Wildt David E.
Published: December 2006

Sustaining viable populations of all wildlife species requires the maintenance of habitat, as well as an understanding of the behaviour and physiology of individual species. Despite substantial efforts, there are thousands of species threatened by extinction, often because of complex factors related to politics, social and environmental conditions and economic needs. When species become critically endangered, ex situ recovery programmes that include reproductive scientists are the usual first line of defence. Despite the potential of reproductive technologies for rapidly increasing numbers in such small populations, there are few examples of success. This is not the result of a failure on the part of the technologies per se, but rather is due to a lack of knowledge about the fundamental biology of the species in question, information essential for allowing reproductive technologies to be effective in the production of offspring. In addition, modern conservation concepts correctly emphasise the importance of maintaining heterozygosity to sustain genetic vigour, thereby limiting the practical usefulness of some procedures (such as nuclear transfer). However, because of the goal of maintaining all extant gene diversity and because, inevitably, many species are (or will become) ‘critically endangered’, it is necessary to explore every avenue for a potential contributory role. There are many ‘emerging technologies’ emanating from the study of livestock and laboratory animals. We predict that a subset of these may have application to the rescue of valuable genes from individual endangered species and eventually to the genetic management of entire populations or species. The present paper reviews the potential candidate techniques and their potential value (and limitations) to the study and conservation of rare wildlife species.
Control of pest mammals for biodiversity protection in Australia. II. Reliability of knowledge
Authors: Reddiex Ben , Forsyth David M.
Published: December 2006

Foxes, wild dogs, feral cats, rabbits, feral pigs, and feral goats are believed to have deleterious impacts on native biodiversity in Australia. However, although considerable resources have been expended controlling these six pest species, there are few reliable estimates of the effects of pest control on native biodiversity. We first show why reliable knowledge of the effects of pest animal control operations can be gained only by adopting proper experimental designs (i.e. treatment and non-treatment areas, replication, and random assignment of treatment and non-treatment areas) and monitoring of both the pest and biodiversity. We then review the design of 1915 pest control actions conducted with the aim of protecting native biodiversity in Australia during 1990–2003. Most (67.5%) pest control actions consisted of a single treatment area without monitoring of either the pest or biodiversity. Only 2.4% of pest control actions had one or more treatment and non-treatment areas, and very few treatment and non-treatment areas (0.3%) were randomly assigned. Replication of treatment and non-treatment areas occurred in only 1.0% of pest control actions. The field of wildlife management has been strongly criticised for its slow adoption of the tenets of experimentation to examine the effects of management actions, and our results show that this criticism applies to mammalian pest control in Australia. Until the principles of experimental design are adopted, knowledge of the effects of mammalian pest control in Australia will remain unreliable.
Application of pharmaceutical drug delivery for biological control of the common brushtail possum in New Zealand: a review
Authors: McDowell A. , McLeod B. J. , Rades T. , Tucker I. G.
Published: December 2006

The common brushtail possum (Trichosurus vulpecula) is the most significant vertebrate pest in New Zealand, being a major ecological threat to the indigenous biodiversity and an economic threat as a vector for bovine tuberculosis. Novel and effective strategies to reduce the population of T. vulpecula are needed urgently. Several biocontrol agents are currently being assessed and from research to date it is likely that the biocontrol agents will be peptide or protein molecules. It is not possible to administer such biocontrol agents alone because they would be degraded rapidly in the animal, especially if delivered orally. Technologies used in the pharmaceutical industry to design efficacious drug-delivery systems for humans and animals can be applied to the design of delivery systems for biocontrol agents used in wildlife management, although there are some unique challenges that must be overcome.
Attractiveness of a novel omnivore bait, PIGOUT®, to feral pigs (Sus scrofa) and assessment of risks of bait uptake by non-target species
Authors: Cowled Brendan D. , Lapidge Steven J. , Smith Michelle , Staples Linton
Published: December 2006

Following a bait-preference pilot study on captive feral pigs, a series of field studies assessed the attractiveness and target-specificity of a prototype manufactured feral pig bait (PIGOUT®). Two promising test baits and fresh meat reference baits were biomarked with iophenoxic acid and aerially distributed in 100-km2 blocks of land infested with feral pigs in western Queensland to assess field uptake and target-specificity without prefeeding. Uptake was assessed by measuring blood iodine levels in aerially shot feral pigs. In all, 80% of feral pigs sampled in a non-toxic PIGOUT®-baited area had significantly elevated blood iodine, compared with 52% of sampled feral pigs in a meat-baited area (although slightly different baiting strategies were employed). No age or sex bias was evident in PIGOUT®-consuming feral pigs. No monitored manufactured baits were consumed by non-target species in 500 bait-nights. Attractiveness and target-specificity trials of ground-laid, unfenced PIGOUT® baits compared with reference baits were subsequently undertaken in several regions of eastern Australia. Results showed that PIGOUT® was consumed readily by feral pigs at all sites, and that it offered significant improvement in target specificity when compared with unfenced wheat or meat baits. However, the baits were consumed by small numbers of macropods, birds and possums. Available evidence indicates that the target-specificity of PIGOUT® bait is highest in the rangelands, reducing slightly in temperate areas and subalpine forests, where abundance of small animals is higher.
Floristic and structural components of habitat use by the eastern pygmy-possum (Cercartetus nanus) in burnt and unburnt habitats
Authors: Tulloch Ayesha I. , Dickman Chris R.
Published: December 2006

The eastern pygmy-possum (Cercartetus nanus) occurs broadly but patchily in south-eastern Australia. It is a small, difficult-to-trap marsupial with poorly known resource and habitat preferences. This study investigated the structural and floristic habitat resources used and selected by C. nanus in Royal National Park (which was heavily burnt by bushfire in 1994) and Heathcote National Park (most of which had remained unburnt for over two decades at the time of study), in central-coastal New South Wales. Three different sampling methods were used – pitfall traps, Elliott traps and hair tubes – with pitfall trapping being by far the most effective method for detecting C. nanus. Live-trapping in different habitats revealed higher numbers of C. nanus in unburnt and burnt woodland, burnt heathland and burnt coastal complex than in unburnt coastal complex and burnt and unburnt rainforest. To identify the components of habitat contributing to this pattern, we first scored floristic and structural features of vegetation around trap stations and then quantified habitat components further by using spool- and radio-tracking. We found little evidence that C. nanus responded to any structural components of habitat, although arboreal activity was greater, not surprisingly, in wooded than in burnt heathland habitats. C. nanus was associated most strongly with the abundance of certain plants in the Proteaceae and Myrtaceae. In particular, the species prefers Banksia spp. (probably for food) and Eucalyptus and Xanthorrhoea spp. (probably for shelter).
Interstrain transfer of the large pathogenicity island (PAPI-1) of
Pseudomonas aeruginosa
Authors: Qiu Xiaoyun , Gurkar Aditi U. , Lory Stephen
Published: December 2006

The large
Pseudomonas aeruginosa
pathogenicity island PAPI-1 of strain PA14 is a cluster of 108 genes that encode a number of virulence features. We demonstrate that, in a subpopulation of cells, PAPI-1 can exist in an extrachromosomal circular form after precise excision from its integration site within the 3′ terminus of the tRNA
Lys
gene. Circular PAPI-1 can reintegrate into either of the two tRNA
Lys
genes, including the one that was used for integration of small pathogenicity island PAPI-2 in strain PA14. The excision requires PAPI-1-encoded integrase, a member of the tyrosine recombinase family. PAPI-1 Soj contains the conserved domains of proteins that are related to chromosome and plasmid partition.
soj
plays a role in maintaining PAPI-1 and mutations in
soj
result in the loss of PAPI-1 from
P. aeruginosa
. We further demonstrate that, during coculture, the PAPI-1-containing strains are able to transfer it into
P. aeruginosa
recipient strains that do not harbor this island naturally. After transfer, PAPI-1 integrates into either of the two tRNA
Lys
genes. PAPI-1 encompasses many features of mobile elements, including mobilization and maintenance modules. Together with the virulence determinants, PAPI-1 plays an important role in the evolution of
P. aeruginosa
, by expanding its natural habitat from soil and water to animal and human infections.
Role of protein frame and solvent for the redox properties of azurin from
Pseudomonas aeruginosa
Authors: Cascella Michele , Magistrato Alessandra , Tavernelli Ivano , Carloni Paolo , Rothlisberger Ursula
Published: December 2006

We have coupled hybrid quantum mechanics (density functional theory; Car–Parrinello)/molecular mechanics molecular dynamics simulations to a grand-canonical scheme, to calculate the
in situ
redox potential of the Cu
2+
+
e
−
→ Cu
+
half reaction in azurin from
Pseudomonas aeruginosa
. An accurate description at atomistic level of the environment surrounding the metal-binding site and finite-temperature fluctuations of the protein structure are both essential for a correct quantitative description of the electronic properties of this system. We report a redox potential shift with respect to copper in water of 0.2 eV (experimental 0.16 eV) and a reorganization free energy λ = 0.76 eV (experimental 0.6–0.8 eV). The electrostatic field of the protein plays a crucial role in fine tuning the redox potential and determining the structure of the solvent. The inner-sphere contribution to the reorganization energy is negligible. The overall small value is mainly due to solvent rearrangement at the protein surface.
Determination of solvent content in cavities in IL-1β using experimentally phased electron density
Authors: Quillin Michael L. , Wingfield Paul T. , Matthews Brian W.
Published: December 2006

The extent to which water is present within apolar cavities in proteins remains unclear. In the case of interleukin-1β (IL-1β), four independent structures solved by x-ray crystallography indicate that water is not present in the central apolar cavity. In contrast, results from NMR spectroscopy suggest that water has high occupancy within the cavity but is positionally disordered, making it undetectable by standard crystallographic methods. A theoretically based crystallographic-phase refinement technique also suggested that there was the equivalent of two fully occupied water molecules within the apolar cavity. To resolve these discrepancies we sought to obtain an experimentally phased electron density map that was free of possible bias caused by mathematical modeling of the protein or the solvent. By combining native diffraction data with multiple wavelength anomalous data from a platinum derivative, accurate phases were obtained. Using these experimental phases, we estimate that occupancy of the apolar cavity in IL-1β by solvent is close or equal to zero. Polar cavities in the protein that contain ordered solvent molecules serve as internal controls.
The structural basis for the mutagenicity of O
6
-methyl-guanine lesions
Authors: Warren Joshua J. , Forsberg Lawrence J. , Beese Lorena S.
Published: December 2006

Methylating agents are widespread environmental carcinogens that generate a broad spectrum of DNA damage. Methylation at the guanine O
6
position confers the greatest mutagenic and carcinogenic potential. DNA polymerases insert cytosine and thymine with similar efficiency opposite O
6
-methyl-guanine (O6MeG). We combined pre-steady-state kinetic analysis and a series of nine x-ray crystal structures to contrast the reaction pathways of accurate and mutagenic replication of O6MeG in a high-fidelity DNA polymerase from
Bacillus stearothermophilus
. Polymerases achieve substrate specificity by selecting for nucleotides with shape and hydrogen-bonding patterns that complement a canonical DNA template. Our structures reveal that both thymine and cytosine O6MeG base pairs evade proofreading by mimicking the essential molecular features of canonical substrates. The steric mimicry depends on stabilization of a rare cytosine tautomer in C·O6MeG–polymerase complexes. An unusual electrostatic interaction between O-methyl protons and a thymine carbonyl oxygen helps stabilize T·O6MeG pairs bound to DNA polymerase. Because DNA methylators constitute an important class of chemotherapeutic agents, the molecular mechanisms of replication of these DNA lesions are important for our understanding of both the genesis and treatment of cancer.
Introduced cryptic species of parasites exhibit different invasion pathways
Authors: Miura Osamu , Torchin Mark E. , Kuris Armand M. , Hechinger Ryan F. , Chiba Satoshi
Published: December 2006

Sometimes infectious agents invade and become established in new geographic regions. Others may be introduced yet never become established because of the absence of suitable hosts in the new region. This phenomenon may be particularly true for the many parasites with complex life cycles, where various life stages require different host species. Homogenization of the world's biota through human-mediated invasions may reunite hosts and parasites, resulting in disease outbreaks in novel regions. Here we use molecular genetics to differentiate invasion pathways for two digenean trematode parasites and their exotic host, the Asian mud snail,
Batillaria attramentaria
. All of the snail haplotypes found in introduced populations in North America were identical to haplotypes common in the areas of Japan that provided oysters for cultivation in North America, supporting the hypothesis that the snails were introduced from Japan with seed oysters. Two cryptic trematode species were introduced to North American populations in high frequencies. We found a marked reduction of genetic variation in one of these species, suggesting it experienced a bottleneck or founder event comparable to that of the host snail. In contrast, no genetic variation was lost in the other parasite species. We hypothesize that this parasite was and is dispersed naturally by migratory shorebirds and was able to establish only after the host snail,
B. attramentaria
, was introduced to North America. Evaluation of the nature of invasion pathways and postinvasion consequences will aid mitigation of spreading diseases of humans, livestock, and wildlife in an increasingly globalized world.
PSD-95 and PKC converge in regulating NMDA receptor trafficking and gating
Authors: Lin Ying , Jover-Mengual Teresa , Wong Judy , Bennett Michael V. L. , Zukin R. Suzanne
Published: December 2006

Neuronal NMDA receptors (NMDARs) colocalize with postsynaptic density protein-95 (PSD-95), a putative NMDAR anchoring protein and core component of the PSD, at excitatory synapses. PKC activation and PSD-95 expression each enhance NMDAR channel opening rate and number of functional channels at the cell surface. Here we show in
Xenopus
oocytes that PSD-95 and PKC potentiate NMDA gating and trafficking in a nonadditive manner. PSD-95 and PKC each enhance NMDA channel activity, with no change in single-channel conductance, reversal potential or mean open time. PSD-95 and PKC each potentiate NMDA channel opening rate (
k
β
) and number of functional channels at the cell surface (N), as indicated by more rapid current decay and enhanced charge transfer in the presence of the open channel blocker MK-801. PSD-95 and PKC each increase NMDAR surface expression, as indicated by immunofluorescence. PKC potentiates NMDA channel function and NMDAR surface expression to the same final absolute values in the absence or presence of PSD-95. Thus, PSD-95 partially occludes PKC potentiation. We further show that Ser-1462, a putative phosphorylation target within the PDZ-binding motif of the NR2A subunit, is required for PSD-95-induced potentiation and partial occlusion of PKC potentiation. Coimmunoprecipitation experiments with cortical neurons in culture indicate that PKC activation promotes assembly of NR2 with NR1, and that the newly assembled NMDARs are not associated with PSD-95. These findings predict that synaptic scaffolding proteins and protein kinases convergently modulate NMDAR gating and trafficking at synaptic sites.
Modern Imaging Technologies in Toxicologic Pathology: An Overview
Authors: Ying Xiaoyou , Monticello Thomas M.
Published: December 2006

Modern imaging technology, now utilized in most biomedical research areas (bioimaging), enables the detection and visualization of biological processes at various levels of the molecule, organelle, cell, tissue, organ and/or whole body. In toxicologic pathology, the impact of modern imaging technology is becoming apparent from digital histopathology to novel molecular imaging for in vivo studies. This overview summarizes recent progresses in digital microscopy imaging and newly developed digital slide techniques. Applications of virtual microscopy imaging are discussed and compared to traditional optical microscopy reading. New generation digital pathology approaches, including automatic slide inspection, digital slide databases and image management are briefly introduced. Commonly used in vivo preclinical imaging technologies are also summarized. While most of these new imaging techniques are still undergoing rapid development, it is important that toxicologic pathologists embrace and utilize these technologies as advances occur.
Toxicity Profiles in Rats Treated with Tumorigenic and Nontumorigenic Triazole Conazole Fungicides: Propiconazole, Triadimefon, and Myclobutanil
Authors: Wolf Douglas C. , Allen James W. , George Michael H. , Hester Susan D. , Sun Guobin , Moore Tanya , Thai Sheau-Fung , Delker Don , Winkfield Ernest , Leavitt Sharon , Nelson Gail , Roop Barbara C. , Jones Carlton , Thibodeaux Julie , Nesnow Stephen
Published: December 2006

Conazoles are a class of azole based fungicides used in agriculture and as pharmaceutical products. They have a common mode of antifungal action through inhibition of ergosterol biosynthesis. Some members of this class have been shown to be hepatotoxic and will induce mouse hepatocellular tumors and/or rat thyroid follicular cell tumors. The particular mode of toxic and tumorigenic action for these compounds is not known, however it has been proposed that triadimefon-induced rat thyroid tumors arise through the specific mechanism of increased TSH. The present study was designed to identify commonalities of effects across the different conazoles and to determine unique features of the tissue responses that suggest a toxicity pathway and a mode of action for the observed thyroid response for triadimefon. Male Wistar/Han rats were treated with triadimefon (100, 500, 1800 ppm), propiconazole (100, 500, 2500 ppm), or myclobutanil (100, 500, 2000 ppm) in feed for 4, 30, or 90 days. The rats were evaluated for clinical signs, body and liver weight, histopathology of thyroid and liver, hepatic metabolizing enzyme activity, and serum T3, T4, TSH, and cholesterol levels. There was a dose-dependent increase in liver weight but not body weight for all treatments. The indication of cytochrome induction, pentoxyresorufin O-dealkylation (PROD) activity, had a dose-related increase at all time points for all conazoles. Uridine diphopho-glucuronosyl transferase (UDPGT), the T4 metabolizing enzyme measured as glucuronidation of 1-naphthol, was induced to the same extent after 30 and 90 days for all three conazoles. Livers from all high dose treated rats had centrilobular hepatocyte hypertrophy after 4 days, while only triadimefon and propiconazole treated rats had hepatocyte hypertrophy after 30 days, and only triadimefon treated rats had hepatocyte hypertrophy after 90 days. Thyroid follicular cell hypertrophy, increased follicular cell proliferation, and colloid depletion were present only after 30 days in rats treated with the high dose of triadimefon. A dose-dependent decrease in T4 was present after 4 days with all 3 compounds but only the high doses of propiconazole and triadimefon produced decreased T4 after 30 days. T3 was decreased after high-dose triadimefon after 4 days and in a dose-dependent manner for all compounds after 30 days. Thyroid hormone levels did not differ from control values after 90 days and TSH was not increased in any exposure group. A unique pattern of toxic responses was not identified for each conazole and the hypothesized mode of action for triadimefon-induced thyroid gland tumors was not supported by the data.
Urothelial Carcinogenesis in the Urinary Bladder of Male Rats Treated with Muraglitazar, a PPARα/γ Agonist: Evidence for Urolithiasis as the Inciting Event in the Mode of Action
Authors: Dominick Mark A. , White Melvin R. , Sanderson Thomas P. , van Vleet Terry , Cohen Samuel M. , Arnold Lora E. , Cano Marty , Tannehill-Gregg Sarah , Moehlenkamp Jeffrey D. , Waites Crystal R. , Schilling Beth E.
Published: December 2006

Muraglitazar, a PPARα/γ agonist, dose-dependently increased urinary bladder tumors in male Harlan Sprague–Dawley (HSD) rats administered 5, 30, or 50 mg/kg/day for up to 2 years. To determine the mode of tumor development, male HSD rats were treated daily for up to 21 months at doses of 0, 1, or 50 mg/kg while being fed either a normal or 1% NH4Cl-acidified diet. Muraglitazar-associated, time-dependent changes in urine composition, urothelial mitogenesis and apoptosis, and urothelial morphology were assessed. In control and treated rats fed a normal diet, urine pH was generally ≥6.5, which facilitates formation of calcium- and magnesium-containing solids, particularly in the presence of other prolithogenic changes in rat urine. Urinary citrate, an inhibitor of lithogenesis, and soluble calcium concentrations were dose dependently decreased in association with increased calcium phosphate precipitate, crystals and/or microcalculi; magnesium ammonium phosphate crystals and aggregates; and calcium oxalate-containing thin, rod-like crystals. Morphologically, sustained urothelial cytotoxicity and proliferation with a ventral bladder predilection were noted in treated rats by month 1 and urinary carcinomas with a similar distribution occurred by month 9. Urothelial apoptotic rates were unaffected by muraglitazar treatment or diet. In muraglitazar-treated rats fed an acidified diet, urine pH was invariably < 6.5, which inhibited formation of calcium- and magnesium-containing solids. Moreover, dietary acidification prevented the urothelial cytotoxic, proliferative, and tumorigenic responses. Collectively, these data support an indirect pharmacologic mode of urinary bladder tumor development involving alterations in urine composition that predispose to urolithiasis and associated decreases in urine-soluble calcium concentrations.
Caveolin-1: a critical regulator of lung fibrosis in idiopathic pulmonary fibrosis
Authors: Wang Xiao Mei , Zhang Yingze , Kim Hong Pyo , Zhou Zhihong , Feghali-Bostwick Carol A. , Liu Fang , Ifedigbo Emeka , Xu Xiaohui , Oury Tim D. , Kaminski Naftali , Choi Augustine M.K.
Published: December 2006

Idiopathic pulmonary fibrosis (IPF) is a progressive chronic disorder characterized by activation of fibroblasts and overproduction of extracellular matrix (ECM). Caveolin-1 (cav-1), a principal component of caveolae, has been implicated in the regulation of numerous signaling pathways and biological processes. We observed marked reduction of cav-1 expression in lung tissues and in primary pulmonary fibroblasts from IPF patients compared with controls. We also demonstrated that cav-1 markedly ameliorated bleomycin (BLM)-induced pulmonary fibrosis, as indicated by histological analysis, hydroxyproline content, and immunoblot analysis. Additionally, transforming growth factor β1 (TGF-β1), the well-known profibrotic cytokine, decreased cav-1 expression in human pulmonary fibroblasts. cav-1 was able to suppress TGF-β1–induced ECM production in cultured fibroblasts through the regulation of the c-Jun N-terminal kinase (JNK) pathway. Interestingly, highly activated JNK was detected in IPF- and BLM-instilled lung tissue samples, which was dramatically suppressed by ad–cav-1 infection. Moreover, JNK1-null fibroblasts showed reduced smad signaling cascades, mimicking the effects of cav-1. This study indicates a pivotal role for cav-1 in ECM regulation and suggests a novel therapeutic target for patients with pulmonary fibrosis.
Puma cooperates with Bim, the rate-limiting BH3-only protein in cell death during lymphocyte development, in apoptosis induction
Authors: Erlacher Miriam , Labi Verena , Manzl Claudia , Böck Günther , Tzankov Alexandar , Häcker Georg , Michalak Ewa , Strasser Andreas , Villunger Andreas
Published: December 2006

The physiological role of B cell lymphoma 2 (Bcl-2) homology 3–only proteins has been investigated in mice lacking the individual genes identifying rate-limiting roles for Bim (Bcl-2–interacting mediator of cell death) and Puma (p53–up-regulated modulator of apoptosis) in apoptosis induction. The loss of Bim protects lymphocytes from apoptosis induced by cytokine deprivation and deregulated Ca++ flux and interferes with the deletion of autoreactive lymphocytes and the shutdown of immune responses. In contrast, Puma is considered the key mediator of p53-induced apoptosis. To investigate the hypothesis that Bim and Puma have overlapping functions, we generated mice lacking both genes and found that bim−/−/puma−/− animals develop multiple postnatal defects that are not observed in the single knockout mice. Most strikingly, hyperplasia of lymphatic organs is comparable with that observed in mice overexpressing Bcl-2 in all hemopoietic cells exceeding the hyperplasia observed in bim−/− mice. Bim and Puma also have clearly overlapping functions in p53-dependent and -independent apoptosis. Their combined loss promotes spontaneous tumorigenesis, causing the malignancies observed in Bcl-2 transgenic mice, but does not exacerbate the autoimmunity observed in the absence of Bim.
Dual decompositions of 4-manifolds III: s-cobordisms
Authors: Quinn Frank
Published: December 2006

The main result is that an s-cobordism (topological or smooth) of 4-manifolds has a product structure outside a “core” sub-s-cobordism. These cores are arranged to have quite a bit of structure, for example they are smooth and abstractly (forgetting boundary structure) diffeomorphic to a standard neighborhood of a 1-complex. The decomposition is highly nonunique so cannot be used to define an invariant, but it shows that the topological s-cobordism question reduces to the core case. The simply-connected version of the decomposition (with 1-complex a point) is due to Curtis, Freedman, Hsiang and Stong. Controlled surgery is used to reduce topological triviality of core s-cobordisms to a question about controlled homotopy equivalence of 4-manifolds. There are speculations about further reductions. The decompositions on the ends of the s-cobordism are “dual decompositions” with homotopically-controlled handle structures, and the main result is an application of earlier papers in the series.
Bochner-Riesz means with respect to a rough distance function
Authors: Taylor Paul
Published: December 2006

The generalized Bochner-Riesz operator

S

R
,
λ

S^{R,\lambda }

may be defined as
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper S Superscript upper R comma lamda Baseline f left-parenthesis x right-parenthesis equals script upper F Superscript negative 1 Baseline left-bracket left-parenthesis 1 minus StartFraction rho Over upper R EndFraction right-parenthesis Subscript plus Superscript lamda Baseline ModifyingAbove f With caret right-bracket left-parenthesis x right-parenthesis">

S

R
,
λ

f
(
x
)
=

F

−
1

[

(
1
−

ρ
R

)

+

λ

f
^

]

(
x
)

\begin{equation*} S^{R,\lambda }f(x) = \mathcal {F}^{-1}\left [\left (1-\frac {\rho }{R}\right )^{\lambda }_+ \widehat {f}\right ](x) \end{equation*}

where

ρ
\rho

is an appropriate distance function and

F

−
1

\mathcal F^{-1}

is the inverse Fourier transform. The behavior of

S

R
,
λ

S^{R,\lambda }

on

L
p

(

R

d

×

R

)

L^p(\mathbf {R}^d\times \mathbf {R})

is described for

ρ
(

ξ
′

,

ξ

d
+
1

)
=
max
{

|

ξ
′

|

,

|

ξ

d
+
1

|

}

\rho (\xi ’,\xi _{d+1})=\max \{|\xi ’|,|\xi _{d+1}|\}

, a rough distance function. We conjecture that this operator is bounded on

R

d

×

R

\mathbf {R}^{d}\times \mathbf {R}

when

λ
>
max
{
d
(

1
2

−

1
p

)
−

1
2

,
0
}

\lambda >\max \{d(\frac {1}{2}-\frac {1}{p})-\frac {1}{2},0\}

and

p
>
2
+

6

d
−
3

p>2+\frac {6}{d-3}

, and unbounded when

p

≥

2

+

6

d
−
3

p \!\geq \!2\!+\!\frac {6}{d-3}

. This conjecture is verified for large ranges of

p
p

.
Nullification and cellularization of classifying spaces of finite groups
Authors: Flores Ramón
Published: December 2006

In this note we discuss the effect of the

B

Z

/

p

\textrm {B}\mathbb {Z}/p

-nullification

P

B

Z

/

p

\mathbf {P}_{\textrm {B}\mathbb {Z}/p}

and the

B

Z

/

p

\textrm {B}\mathbb {Z}/p

-cellularization

C
W

B

Z

/

p

\mathbf {CW}_{\textrm {B}\mathbb {Z}/p}

over classifying spaces of finite groups, and we relate them with the corresponding functors with respect to Moore spaces that have been intensively studied in the last years. We describe

P

B

Z

/

p

B

G

\mathbf {P}_{\textrm {B}\mathbb {Z}/p}\textrm {B}G

by means of a covering fibration, and we classify all finite groups

G
G

for which

B

G

\textrm {B}G

is

B

Z

/

p

\textrm {B}\mathbb {Z}/p

-cellular. We also carefully study the analogous functors in the category of groups, and their relationship with the fundamental groups of

P

B

Z

/

p

B

G

\mathbf {P}_{\textrm {B}\mathbb {Z}/p}\textrm {B}G

and

C
W

B

Z

/

p

B

G
.

\mathbf {CW}_{\textrm {B}\mathbb {Z}/p}\textrm {B}G.
Translation equivalence in free groups
Authors: Kapovich Ilya , Levitt Gilbert , Schupp Paul , Shpilrain Vladimir
Published: December 2006

Motivated by the work of Leininger on hyperbolic equivalence of homotopy classes of closed curves on surfaces, we investigate a similar phenomenon for free groups. Namely, we study the situation when two elements

g
,
h

g,h

in a free group

F
F

have the property that for every free isometric action of

F
F

on an

R

\mathbb {R}

-tree

X
X

the translation lengths of

g
g

and

h
h

on

X
X

are equal.
Lattice-ordered Abelian groups and Schauder bases of unimodular fans
Authors: Manara Corrado , Marra Vincenzo , Mundici Daniele
Published: December 2006

Baker-Beynon duality theory yields a concrete representation of any finitely generated projective Abelian lattice-ordered group

G
G

in terms of piecewise linear homogeneous functions with integer coefficients, defined over the support

|

Σ

|

|\Sigma |

of a fan

Σ
\Sigma

. A unimodular fan

Δ
\Delta

over

|

Σ

|

|\Sigma |

determines a Schauder basis of

G
G

: its elements are the minimal positive free generators of the pointwise ordered group of

Δ
\Delta

-linear support functions. Conversely, a Schauder basis

H

\mathbf {H}

of

G
G

determines a unimodular fan over

|

Σ

|

|\Sigma |

: its maximal cones are the domains of linearity of the elements of

H

\mathbf {H}

. The main purpose of this paper is to give various representation-free characterisations of Schauder bases. The latter, jointly with the De Concini-Procesi starring technique, will be used to give novel characterisations of finitely generated projective Abelian lattice ordered groups. For instance,

G
G

is finitely generated projective iff it can be presented by a purely lattice-theoretical word.
Algebraic independence in the Grothendieck ring of varieties
Authors: Naumann N.
Published: December 2006

We give sufficient cohomological criteria for the classes of given varieties over a field

k
k

to be algebraically independent in the Grothendieck ring of varieties over

k
k

and construct some examples.
A complex Frobenius theorem, multiplier ideal sheaves and Hermitian-Einstein metrics on stable bundles
Authors: Weinkove Ben
Published: December 2006

A complex Frobenius theorem is proved for subsheaves of a holomorphic vector bundle satisfying a finite generation condition and a differential inclusion relation. A notion of ‘multiplier ideal sheaf’ for a sequence of Hermitian metrics is defined. The complex Frobenius theorem is applied to the multiplier ideal sheaf of a sequence of metrics along Donaldson’s heat flow to give a construction of the destabilizing subsheaf appearing in the Donaldson-Uhlenbeck-Yau theorem, in the case of algebraic surfaces.
Some characterizations of space-forms
Authors: Pigola Stefano , Rigoli Marco , Setti Alberto
Published: December 2006

Integral conditions on the traceless Ricci tensor are used to characterize Euclidean and hyperbolic spaces among complete, locally conformally flat manifolds of constant scalar curvature. The main tools are vanishing-type results for

L

p

L^{p}

-solutions of a large class of differential inequalities. Further applications of the technique are also given.
C*-algebras associated with interval maps
Authors: Deaconu Valentin , Shultz Fred
Published: December 2006

For each piecewise monotonic map

τ
\tau

of

[
0
,
1
]

[0,1]

, we associate a pair of C*-algebras

F
τ

F_\tau

and

O
τ

O_\tau

and calculate their K-groups. The algebra

F
τ

F_\tau

is an AI-algebra. We characterize when

F
τ

F_\tau

and

O
τ

O_\tau

are simple. In those cases,

F
τ

F_\tau

has a unique trace, and

O
τ

O_\tau

is purely infinite with a unique KMS state. In the case that

τ
\tau

is Markov, these algebras include the Cuntz-Krieger algebras

O
A

O_A

, and the associated AF-algebras

F
A

F_A

. Other examples for which the K-groups are computed include tent maps, quadratic maps, multimodal maps, interval exchange maps, and

β
\beta

-transformations. For the case of interval exchange maps and of

β
\beta

-transformations, the C*-algebra

O
τ

O_\tau

coincides with the algebras defined by Putnam and Katayama-Matsumoto-Watatani, respectively.
Weakly Lefschetz symplectic manifolds
Authors: Fernández M. , Muñoz V. , Ugarte L.
Published: December 2006

For a symplectic manifold, the harmonic cohomology of symplectic divisors (introduced by Donaldson, 1996) and of the more general symplectic zero loci (introduced by Auroux, 1997) are compared with that of its ambient space. We also study symplectic manifolds satisfying a weakly Lefschetz property, that is, the

s
s

–Lefschetz property. In particular, we consider the symplectic blow-ups

C
P

~

m

\widetilde {CP}{}^m

of the complex projective space

C
P

m

{CP}^m

along weakly Lefschetz symplectic submanifolds

M
⊂

C
P

m

M\subset {CP}^m

. As an application we construct, for each even integer

s
≥
2

s\geq 2

, compact symplectic manifolds which are

s
s

–Lefschetz but not

(
s
+
1
)

(s+1)

–Lefschetz.
Values of Gauss maps of complete minimal surfaces in ℝ^{𝕞} on annular ends
Authors: Jin Lu , Ru Min
Published: December 2006

Let

M
M

be a complete minimal surface in

R

m

{\mathbb {R}}^{m}

and let

A
A

be an annular end of

M
M

which is conformal to

{
z
 

|

 
0
>
1

/

r
>

|

z

|

>
r
}

\{z~|~ 0 > 1/r>|z|>r\}

, where

z
z

is the conformal coordinate. Let

G
G

be the generalized Gauss map of

M
M

. We show that

G
(
A
)

G(A)

must intersect every hyperplane in

P

m
−
1

(

C

)

{\mathbb {P}}^{m-1}({\mathbb {C}})

, with the possible exception of

m
(
m
+
1
)

/

2

m(m+1)/2

hyperplanes in general position.
Primeness, semiprimeness and localisation in Iwasawa algebras
Authors: Ardakov Konstantin , Brown Kenneth
Published: December 2006

Necessary and sufficient conditions are given for the completed group algebras of a compactpp-adic analytic group with coefficient ring thepp-adic integers or the field ofppelements to be prime, semiprime and a domain. Necessary and sufficient conditions are found for the localisation at semiprime ideals related to the augmentation ideals of closed normal subgroups. Some information is obtained about the Krull and global dimensions of the localisations. The results extend and complete work of A. Neumann and J. Coateset al.
Compactness properties of Sobolev imbeddings for rearrangement invariant norms
Authors: Curbera Guillermo , Ricker Werner
Published: December 2006

Compactness properties of Sobolev imbeddings are studied within the context of rearrangement invariant norms. Attention is focused on the extremal situation, namely, when the imbedding is considered as defined on its optimal Sobolev domain (with the range space fixed). The techniques are based on recent results which reduce the question of boundedness of the imbedding to boundedness of an associated kernel operator (of just one variable).
Crossings and nestings of matchings and partitions
Authors: Chen William , Deng Eva , Du Rosena , Stanley Richard , Yan Catherine
Published: December 2006

We present results on the enumeration of crossings and nestings for matchings and set partitions. Using a bijection between partitions and vacillating tableaux, we show that if we fix the sets of minimal block elements and maximal block elements, the crossing number and the nesting number of partitions have a symmetric joint distribution. It follows that the crossing numbers and the nesting numbers are distributed symmetrically over all partitions of

[
n
]

[n]

, as well as over all matchings on

[
2
n
]

[2n]

. As a corollary, the number of

k
k

-noncrossing partitions is equal to the number of

k
k

-nonnesting partitions. The same is also true for matchings. An application is given to the enumeration of matchings with no

k
k

-crossing (or with no

k
k

-nesting).
A new type of concentration solutions for a singularly perturbed elliptic problem
Authors: Dancer E. , Yan Shusen
Published: December 2006

We prove the existence of positive solutions concentrating on some higher dimensional manifolds near the boundary of the domain for a nonlinear singularly perturbed elliptic problem.
Richard Stafford Cripps, 1889-1952
Authors: Schuster George
Published: December 2006

Stafford Cripps was a man who ‘believed firmly’ and ‘did faithfully.’ He was one of the few to whom the opportunity was given to match his great qualities with the needs of a great hour—a critical hour in the history of Britain. It was written of him when he died that he had been ‘for twenty years one of the most remarkable individual forces in British politics’* ; but in his public life his culminating achievement—that which has had a lasting effect on the social and economic history of Britain and that by which his character can best be judged—was his conduct in the years after October 1947 when he became the first man to combine the offices of Minister of Economic Affairs and Chancellor of the Exchequer. All he did then was based on his intense feeling of the public need and his simple conviction that the nation could overcome its economic problems only by improvement in productive effort combined with restraint in expenditure. He expressed this conviction firmly and courageously in his policy, but above all, and this was his great personal achievement, he was able to impress the same conviction on the Trade Union leaders. He did more than any man to get across to the Trades Union Congress the realities of the national economic problems and to make Trade Unionists realize that the only sure way to improve earnings and standards of living was to increase the productivity of labour. * The Times 22 April 1952.
Edward Mellanby, 1884-1955
Authors: Dale Henry Hallett
Published: December 2006

Death came suddenly, and without recognized warning, to Sir Edward Mellanby on 30 January 1955, before he had completed his 71st year. Nearly six years earlier he had retired, on reaching the official age-limit, from the Secretaryship of the Medical Research Council, which he had held for 16 years. During this period the range and the influence of the Council’s activities for the promotion and support of medical research had undergone a most notable expansion, primarily in the United Kingdom, but widely beyond it also in the British Commonwealth; and Mellanby’s enlightened and resourceful enterprise in proposal and planning, and his vigorous drive in administrative action, had undoubtedly been dominant factors in this remarkable development. Like his only predecessor in the appointment, the late Walter Morley Fletcher, Mellanby had been the Council’s chief executive officer in much more than a merely official sense. Yet, during all the years in which he had carried that heavy load of official responsibility, he had succeeded in maintaining a direct and personal activity in the researches which had so long provided for him, and also for his devoted wife and scientific partner, the central aim and interest of their joint working lives.
George Frederick Charles Searle, 1864-1954
Authors: Thomson George Paget
Published: December 2006

George Frederick Charles Searle was born on 3 December 1864 at the village of Oakington in Cambridgeshire, of which his father, the Rev. W. G. Searle, was vicar. He was the eldest of five children, three boys and two girls. His schooling was limited to six days at the village school, otherwise he was taught by his father, who though a Wrangler was more interested in languages, and taught him Hebrew as well as more usual subjects. G.F.C. retained enough Hebrew in later life to impress the custodian of a synagogue at Gibraltar. He taught himself the use of tools, which was a life-long pleasure. He constructed a dynamo while a boy. At the age of 14 he was taken by Clerk Maxwell round the Cavendish Laboratory, which deeply impressed him, and seems to have turned his thoughts to the direction of physics. He was a tall, well-built man of a little under six foot in height. As an undergraduate he gained a half-blue for cycling, then an important sport, and continued to bicycle for pleasure and utility to an advanced age, but he was not interested in games, nor did he greatly care for walking. After a period of private coaching lasting about 18 months with a Mr Barrel, Searle came up to Cambridge with a foundation scholarship to Peterhouse. He read mathematics and was placed 28th Wrangler in the Tripos of 1887. He then studied for Part II of the Natural Sciences Tripos in which he took a second class next year.
Patrick Alfred Buxton, 1892-1955
Authors: Wigglesworth Vincent Brian
Published: December 2006

Patrick Alfred Buxton was born in Hyde Park Street, Paddington, on 24 March 1892, and died at his home in Gerrards Cross, Bucks on 13 December 1955. His father was Alfred Fowell Buxton, a busy banker and one time chairman of the London County Council, his mother was Violet Jex-Blake. His father’s family was part of that immense group of Buxtons, Gurneys, Barclays, Hammonds, Hoares, many of them resident in Norfolk and many of them Quakers, whose names appear in the annals of business in this country, in banking, in brewing, in the wool trade and so on, over many centuries. This reputation for acumen in business was often combined with a most practical interest in philanthropy and in political or social reform. One may recall the active part played by Sir Thomas Fowell Buxton in association with Wilberforce in the abolition of the slave trade; and the part played by his sister-in-law Elizabeth Fry in prison reform, and of his grandson Sydney Charles Buxton who sponsored the Wild Birds Protection Act of 1902 and did much to improve conditions of employment. Some branches of the group, for example Hambury the gardener and Francis Galton, were prominent in science—but to trace a connexion between Patrick Buxton and Galton one would have to go back five or six generations to David Barclay, son of Robert Barclay ‘the Quaker apologist’. Among the distinctions of these ramifying families literature is hardly represented and the arts not at all—most were country gentlemen, good naturalists, and strongly averse to things academic. His mother’s family was not numerous; they were mostly farmers and landowners in West Norfolk. His grandfather on his mother’s side, Thomas William Jex-Blake, was a classical scholar, Headmaster of Cheltenham and Rugby schools and then dean of Wells—with a strong antipathy to biology and the sciences in general. He married a Cordery and had a large family, several of them very able, among whom one might mention Kathleen Jex-Blake, classical scholar and Mistress of Girton, Cambridge, Henrietta JexBlake, Principal of Lady Margaret Hall, Oxford and Arthur Jex-Blake an able scholarly medical man.