bluuebunny/crossref_metadata_2025 huggingface dataset:
Quarter-stratifiability in ordered spaces
Authors: Bennett Harold , Lutzer David
Published: February 2006

In this paper we study Banakh’s quarter-stratifiability among generalized ordered (GO)-spaces. All quarter-stratifiable GO-spaces have a

σ
\sigma

-closed-discrete dense set and therefore are perfect, and have a

G
δ

G_\delta

-diagonal. We characterize quarter-stratifiability among GO-spaces and show that, unlike the situation in general topological spaces, quarter-stratifiability is a hereditary property in GO-spaces. We give examples showing that a separable perfect GO-space with a

G
δ

G_\delta

-diagonal can fail to be quarter-stratifiable and that any GO-space constructed on a Q-set in the real line must be quarter-stratifiable.
A characterisation of 0^{#} in terms of forcing
Authors: Friedman Sy
Published: February 2006

We show that “saturation” of the universe with respect to forcing over

L
L

with partial orders on

ω
1

\omega _1

is equivalent to the existence of

0
#

0^\#

.
Almost everywhere convergence of inverse Fourier transforms
Authors: Colzani Leonardo , Meaney Christopher , Prestini Elena
Published: February 2006

We show that if

log
⁡
(
2
−
Δ
)
f
∈

L
2

(

R

d

)

\log (2-\Delta )f\in L^2({\mathbb R}^d)

, then the inverse Fourier transform of

f
f

converges almost everywhere. Here the partial integrals in the Fourier inversion formula come from dilates of a closed bounded neighbourhood of the origin which is star shaped with respect to

0
0

. Our proof is based on a simple application of the Rademacher-Menshov Theorem. In the special case of spherical partial integrals, the theorem was proved by Carbery and Soria. We obtain some partial results when

log
⁡
(
2
−
Δ
)

f
∈

L
2

(

R

d

)

\sqrt {\log (2-\Delta )}f\in L^2({\mathbb R}^d)

and

log
⁡
log
⁡
(
4
−
Δ
)
f
∈

L
2

(

R

d

)

\log \log (4-\Delta )f\in L^2({\mathbb R}^d)

. We also consider sequential convergence for general elements of

L
2

(

R

d

)

L^2({\mathbb R}^d)

.
The rank of elliptic curves with rational 2-torsion points over large fields
Authors: Im Bo-Hae
Published: February 2006

Let

K
K

be a number field,

K
¯

\overline {K}

an algebraic closure of

K
K

,

G
K

G_K

the absolute Galois group

Gal
⁡
(

K
¯

/

K
)

\operatorname {Gal}(\overline {K}/K)

,

K

a
b

K_{ab}

the maximal abelian extension of

K
K

and

E

/

K

E/K

an elliptic curve defined over

K
K

. In this paper, we prove that if all 2-torsion points of

E

/

K

E/K

are

K
K

-rational, then for each

σ
∈

G
K

\sigma \in G_K

,

E
(
(

K

a
b

)

σ

)

E((K_{ab})^{\sigma })

has infinite rank, and hence

E
(

K
¯

σ

)

E(\overline {K}^{\sigma })

has infinite rank.
Scalar-valued dominated polynomials on Banach spaces
Authors: Botelho Geraldo , Pellegrino Daniel
Published: February 2006

It is well known that 2-homogeneous polynomials on

L

∞

{\mathcal L}_\infty

-spaces are 2-dominated. Motivated by the fact that related coincidence results are possible only for polynomials defined on symmetrically regular spaces, we investigate the situation in several classes of symmetrically regular spaces. We prove a number of non-coincidence results which makes us suspect that there is no infinite dimensional Banach space

E
E

such that every scalar-valued homogeneous polynomial on

E
E

is

r
r

-dominated for every

r
≥
1

r \geq 1

.
Homogeneous solutions to fully nonlinear elliptic equations
Authors: Nadirashvili Nikolai , Yuan Yu
Published: February 2006

We classify homogeneous degree

d
≠
2

d\neq 2

solutions to fully nonlinear elliptic equations.
Hausdorff ultrafilters
Authors: Di Nasso Mauro , Forti Marco
Published: February 2006

We give the name Hausdorff to those ultrafilters that provide ultrapowers whose natural topology (

S
S

-topology) is Hausdorff, e.g. selective ultrafilters are Hausdorff. Here we give necessary and sufficient conditions for product ultrafilters to be Hausdorff. Moreover we show that no regular ultrafilter over the “small” uncountable cardinal

u

\mathfrak {u}

can be Hausdorff. (

u

\mathfrak {u}

is the least size of an ultrafilter basis on

ω
\omega

.) We focus on countably incomplete ultrafilters, but our main results also hold for

κ
\kappa

-complete ultrafilters.
A note on non-existence results for semi-linear cooperative elliptic systems via moving spheres
Authors: Zou Henghui
Published: February 2006

In this note, we extend some earlier non-existence, monotonicity and one-dimensionality results of W. Reichel and the author, by replacing the local Lipschitz continuity hypothesis on the non-linearities by a so-called boundedly uniform Lipschitz condition in the magnitude of

u

\mathbf {u}

.
Community‐level birth rate: a missing link between ecology, evolution and diversity
Authors: Bruun H. H. , Ejrnæs R.
Published: February 2006

We propose a conceptual model to explain the variation in species richness in local communities and in build‐up of regional species pools over time. The idea is that the opportunity for new species to enter a community (its invasibility) determines the present richness of that community as well as the long‐term build‐up of a species pool by speciation and migration. We propose that a community's invasibility is determined by the turnover rate of reproductive genets in the community, which we call the ‘community‐level birth rate’. The faster the turn‐over, the more species will accumulate per unit time and per unit community size (number of genets) at a given per‐birth rate of immigration and speciation. Spatially discrete communities inhabiting similar environments sum up to metacommunities, whose inhabitant species constitute the regional species pool. We propose that the size of a regional species pool is determined by the aggregate community‐level birth rate, the size of the metacommunity through time and age of the metacommunity. Thus, the novel contribution is our proposal of a direct effect of local environment on the build‐up rate of species pools. The relative importance of immigrating species and neospecies originating locally will change with the temporal and spatial scale under consideration. We propose that the diversification rate specific to evolutionary lineages and the build‐up rate of species pools are two sides of the same coin, and that they are both depending on mean generation time. The proposed model offers a reconciliation of two contrasting paradigms in current community ecology, viz. one focussing on present‐time ecological processes and one focussing on historical events governing the size of species pools which in turn determines local richness.
Interpatch movement and edge effects: the role of behavioral responses to the landscape matrix
Authors: J. Haynes Kyle , T. Cronin James
Published: February 2006

Animal interpatch movement and spatial distribution are known to be influenced substantially by the composition of the landscape matrix, but little is known about the underlying mechanisms. In previous mark–recapture experiments we have found that the rates of emigration and immigration for the planthopper Prokelisia crocea are greater within a matrix composed of the introduced grass smooth brome (Bromus inermis) than a mudflat matrix. Additionally, census data indicated that individuals aggregate near the edge of host‐plant patches (prairie cordgrass; Spartina pectinata) bordered by mudflat, but not in patches bordered by nonhost grasses such as brome. Here, we investigate the mechanistic basis of these matrix effects by tracking the individual movements of planthoppers released at the edge of brome‐ and mudflat‐bordered cordgrass patches, and within homogeneous habitats of each type (cordgrass, brome, and mudflat). We found that patch edges bordered by brome were three times more permeable to emigration than mudflat‐bordered edges. Also, planthoppers exhibited no tendency to avoid edges by moving away (i.e. towards the patch interior). Within homogeneous habitats, comparison of the fractal dimension of movement paths revealed that movement was more linear in mudflat than in brome or cordgrass. In addition, planthoppers exhibited greater step lengths (distance moved per 10‐min interval), shorter residency times (duration of pauses between movements), and greater rates of net linear displacement in mudflat than brome and cordgrass. We attribute the planthopper's distributional patterns within patches to the lower permeability of mudflat than nonhost grass edges and the absence of edge–avoidance behavior. Contrary to conventional wisdom that low‐resistance matrix types (e.g. those that promote high displacement rates) enhance interpatch dispersal rates, dispersal success may be higher in brome matrix because tortuous movement through this matrix increases the planthopper's rate of encounter with cordgrass patches.
Disentangling interference competition from exploitative competition in a crab–bivalve system using a novel experimental approach
Authors: Smallegange Isabel M. , Van Der Meer Jaap , Kurvers Ralf H. J. M.
Published: February 2006

In predator–prey relationships such as those between crabs and their bivalve prey, interference competition is a topic of intense investigation as it can have profound consequences on the dynamics of both predator and prey populations. However in laboratory experiments – also those on crab–bivalve systems – workers never adequately disentangled interference competition from exploitative competition, as prey depletion was never compensated. Hitherto, experimental studies on crab–bivalve systems lack direct behavioural observations and have provided only indirect and thus inconclusive evidence of interference competition. We studied interference competition in adult male shore crabs Carcinus maenas that foraged on blue mussels Mytilus edulis. We developed a novel type of experimental tank to replenish each consumed mussel, and thus to keep prey levels constant. We conducted two experiments in which we varied number of crabs (1, 2, 4) and number of mussels (first experiment: 4, 8, 16, 32; second experiment: 8, 32, 128) and directly observed the foraging behaviour of crabs (foraging area=0.25 m2). In the first experiment, feeding rates decreased with increasing crab density only at mussel density 16 because both search time and time spent in agonistic interactions increased. At other mussel densities, variation in crab density did not affect feeding rates, possibly because of low statistical power and the narrow range of mussel densities offered. In the second experiment feeding rates decreased with increasing crab density because crabs spent more time in agonistic interactions and handling their prey. Feeding rates increased with increasing mussel density. Overall, crabs spent on average 14–18% of their foraging time in agonistic behaviours, while on three out of 64 occasions feeding rates decreased because mussels were stolen (kleptoparasitism). Concluding, we have shown that interference competition occurs in absence of prey depletion, while conducting direct behavioural observations aid to identify the behavioural processes that underlie interference competition.
Seed size and plant strategy across the whole life cycle
Authors: Moles Angela T. , Westoby Mark
Published: February 2006

We compiled information from the international literature to quantify the relationships between seed mass and survival through each of the hazards plants face between seed production and maturity. We found that small‐seeded species were more abundant in the seed rain than large‐seeded species. However, this numerical advantage was lost by seedling emergence. The disadvantage of small‐seeded species probably results from size‐selective post‐dispersal seed predation, or the longer time small‐seeded species spend in the soil before germination. Seedlings from large‐seeded species have higher survival through a given amount of time as seedlings. However, this advantage seems to be countered by the greater time taken for large‐seeded species to reach reproductive maturity: our data suggested no relationship, or perhaps a weak negative relationship, between seed size and survival from seedling emergence through to adulthood. A previous compilation showed that the inverse relationship between seed mass and the number of seeds produced per unit canopy area per year is countered by positive relationships between seed mass, plant size and plant longevity. Taken together, these data show that our old understanding of a species’ seed mass as the result of a trade–off between producing a few large offspring, each with high survival probability, versus producing many small offspring each with a lower chance of successfully establishing was incomplete. It seems more likely that seed size evolves as part of a spectrum of life history traits, including plant size, plant longevity, juvenile survival rate and time to reproduction.
Effects of cognitive abilities on metapopulation connectivity
Authors: Vuilleumier Séverine , Perrin Nicolas
Published: February 2006

Connectivity among demes in a metapopulation depends on both the landscape's and the focal organism's properties (including its mobility and cognitive abilities). Using individual‐based simulations, we contrast the consequences of three different cognitive strategies on several measures of metapopulation connectivity. Model animals search suitable habitat patches while dispersing through a model landscape made of cells varying in size, shape, attractiveness and friction. In the blind strategy, the next cell is chosen randomly among the adjacent ones. In the near‐sighted strategy, the choice depends on the relative attractiveness of these adjacent cells. In the far‐ sighted strategy, animals may additionally target suitable patches that appear within their perceptual range.

Simulations show that the blind strategy provides the best overall connectivity, and results in balanced dispersal. The near‐sighted strategy traps animals into corridors that reduce the number of potential targets, thereby fragmenting metapopulations in several local clusters of demes, and inducing sink–source dynamics. This sort of local trapping is somewhat prevented in the far‐sighted strategy. The colonization success of strategies depends highly on initial energy reserves: blind does best when energy is high, near‐sighted wins at intermediate levels, and far‐sighted outcompetes its rivals at low energy reserves.

We also expect strong effects in terms of metapopulation genetics: the blind strategy generates a migrant‐pool mode of dispersal that should erase local structures. By contrast, near‐ and far‐sighted strategies generate a propagule‐pool mode of dispersal and source–sink behavior that should boost structures (high genetic variance among‐ and low variance within local clusters of demes), particularly if metapopulation dynamics is also affected by extinction–colonization processes.

Our results thus point to important effects of the cognitive ability of dispersers on the connectivity, dynamics and genetics of metapopulations.
Seeing the trees for the leaves – oaks as mosaics for a host‐specific moth
Authors: Roslin Tomas , Gripenberg Sofia , Salminen Juha‐Pekka , Karonen Maarit , B. O'Hara Robert , Pihlaja Kalevi , Pulkkinen Pertti
Published: February 2006

From the perspective of a specialist herbivore, how homogenous are individual tree crowns as patches of habitat? We partitioned variation in physical and chemical host leaf traits and in the abundance and performance of a specialist oak leaf miner, Tischeria ekebladella, into variation at different hierarchical levels. For the phenolic contents of the leaves, we examined variation among oak stands, among trees within stands and among branches within trees. For leaf size and water content, we assessed variation among trees within a single stand, among shoots within trees, and among leaves within shoots. For moth abundance and performance, we examined variation across all levels: among oak stands, among trees within stands, among branches within trees, among shoots within branches and among leaves and insect individuals.

For measures of phenolic contents, we found little variation among stands but substantial variation among individual trees. Yet, a tree particularly rich in a given compound was often comparatively poor in another. At a finer spatial scale, the phenolic composition of individual parts of a single tree was quite consistent, whereas leaf weight and water content varied widely within individual tree crowns. Moth abundances varied more among shoots within branches than at any other spatial level, whereas moth survival showed equal levels of variation within individual shoots as among separate oak stands. Likewise, for four other measures of larval performance (assessed at the level of trees and lower), we found more variation within than between trees.

In conclusion, the large variation observed in the performance of a specialist moth and in the physical traits of the leaves among different parts of single tree crowns refutes the image of an oak tree as an ‘island’ of internally homogeneous quality. Hence, we may expect little evolutionary adaptation of T. ekebladella at the scale of individual trees. The moths may instead evolve to behaviourally select their resource at a very fine scale. Large variation within trees also calls for extensive replication within trees in ecological sampling designs and/or the sampling of maximally similar leaves.
Structure in plant–animal interaction assemblages
Authors: Lewinsohn Thomas M. , Inácio Prado Paulo , Jordano Pedro , Bascompte Jordi , M. Olesen Jens
Published: February 2006

We present a comprehensive approach to detect pattern in assemblages of plant and animal species linked by interactions such as pollination, frugivory or herbivory. Simple structural models produce gradient, compartmented or nested patterns of interaction; intermediate patterns between a gradient and compartments are possible, and nesting within compartments produces a combined model. Interaction patterns can be visualized and analyzed either as matrices, as bipartite networks or as multivariate sets through correspondence analysis. We argue that differences among patterns represent outcomes of distinct evolutionary and ecological processes in these highly diversified assemblages. Instead of choosing one model a priori, assemblages should be probed for a suite of patterns. A plant–pollinator assemblage exemplifies a simple nested pattern, whereas a plant–herbivore assemblage illustrates a compound pattern with nested structures within compartments. Compartmentation should reflect coevolutionary histories and constraints, whereas differences in species abundance or dispersal may generate nestedness.
Review article: the role of acid suppression in patients with non‐erosive reflux disease or functional heartburn
Authors: DEVAULT K. R.
Published: February 2006

When patients with the typical reflux symptoms of heartburn, regurgitation, or both, undergo endoscopy, up to 75% will not have endoscopic oesophagitis or evidence of Barrett's oesophagus. These patients have been described as having endoscopic negative or, more commonly, non‐erosive reflux disease (NERD).

Patients without oesophagitis, but with a positive pH test, can be diagnosed with gastro‐oesophageal reflux disease (GERD). Some experts also consider a response to proton pump inhibitor therapy as proof of GERD in a patient with the correct symptoms and a negative endoscopy.

Patients with normal acid exposure, but who report symptoms with a majority of their reflux episodes documented during an ambulatory pH study, have also been considered to have NERD, although others have labelled them as having ‘functional heartburn’.

Finally, there are some patients who have reflux symptoms and respond to reflux therapy, but have no demonstrable reflux by either endoscopy or ambulatory reflux testing. Whether these patients are part of the GERD spectrum or have another diagnosis is not clear.

It seems that the most widely used definition of functional disease (the Rome II criteria) would include these patients as having functional heartburn, as it was defined as ‘greater than or equal to 12 weeks of either continuous or intermittent symptoms of burning retrosternal discomfort or pain without pathologic GERD, achalasia, or other motility disorders with a recognized pathologic basis’.

This article reviews potential differences in pathophysiology between erosive oesophagitis and NERD; explores whether symptoms can help distinguish NERD patients from erosive oesophagitis patients; and explores the evaluation and therapy of these patients.
Review article: modern technology in the diagnosis of gastro‐oesophageal reflux disease – Bilitec, intraluminal impedance and Bravo capsule pH monitoring
Authors: HIRANO I.
Published: February 2006

Ambulatory pH monitoring detects abnormal levels of acid reflux in the oesophagus and can be used to correlate patients’ symptoms with oesophageal acid exposure. Catheter‐based pH testing has several limitations, including issues of sensitivity, specificity, tolerability and the inability to record non‐acid reflux events.

In an effort to improve upon these drawbacks, several devices have been introduced, including the Bilitec system for measuring duodenogastro‐oesophageal reflux; intraluminal impedance monitoring, which detects the distribution, composition and clearing of both acid and non‐acid oesophageal reflux; and a wireless pH monitoring device, the Bravo capsule.

Initial investigations using the Bilitec system demonstrated that duodenogastro‐oesophageal reflux tracked very closely with acid reflux and decreased with proton‐pump inhibitor (PPI) therapy, casting doubt on the clinical utility of Bilitec monitoring. Recent evidence revealed a possible role for duodenogastro‐oesophageal reflux in a subset of patients who continue to report reflux symptoms in the setting of normalized oesophageal acid exposure on high‐dose PPI therapy.

When combined with pH monitoring, impedance monitoring enhances the detection and characterization of gastro‐oesophageal reflux and may have a role in the evaluation of certain specific gastro‐oesophageal reflux disease (GERD) symptoms that persist despite acid suppression therapy.

The utility of the Bravo wireless technology for GERD diagnosis has been validated in several studies, with improvements over catheter‐based pH monitoring in tolerability, accuracy and sensitivity, as well as the ability to record periods both off and on PPI therapy in a single study.

All three diagnostic modalities have advanced the understanding of GERD pathogenesis, but their impact on the clinical management of GERD is still the focus of active investigation.
Auxin controls local cytokinin biosynthesis in the nodal stem in apical dominance
Authors: Tanaka Mina , Takei Kentaro , Kojima Mikiko , Sakakibara Hitoshi , Mori Hitoshi
Published: February 2006

In intact plants, the shoot apex grows predominantly and inhibits outgrowth of axillary buds. After decapitation of the shoot apex, outgrowth of axillary buds begins. This phenomenon is called an apical dominance. Although the involvement of auxin, which represses outgrowth of axillary buds, and cytokinin (CK), which promotes outgrowth of axillary buds, has been proposed, little is known about the underlying molecular mechanisms. In the present study, we demonstrated that auxin negatively regulates local CK biosynthesis in the nodal stem by controlling the expression level of the pea (Pisum sativumL.) gene adenosine phosphate–isopentenyltransferase (PsIPT), which encodes a key enzyme in CK biosynthesis. Before decapitation, PsIPT1 and PsIPT2 transcripts were undetectable; after decapitation, they were markedly induced in the nodal stem along with accumulation of CK. Expression of PsIPT was repressed by the application of indole‐3‐acetic acid (IAA). In excised nodal stem, PsIPT expression and CK levels also increased under IAA‐free conditions. Furthermore, β‐glucuronidase expression, under the control of the PsIPT2 promoter region in transgenic Arabidopsis, was repressed by an IAA. Our results indicate that in apical dominance one role of auxin is to repress local biosynthesis of CK in the nodal stem and that, after decapitation, CKs, which are thought to be derived from the roots, are locally biosynthesized in the nodal stem rather than in the roots.
Impact of basic FGF expression in astrocytes on dopamine neuron synaptic function and development
Authors: Forget Caroline , Stewart Jane , Trudeau Louis‐Éric
Published: February 2006

Behavioural sensitization to amphetamine (AMPH) requires action of the drug in the ventral midbrain where dopamine (DA) neurons are located. In vivo studies suggest that AMPH sensitization requires enhanced expression of basic fibroblast growth factor (bFGF) in the nucleus of midbrain astrocytes. One idea is that the AMPH‐induced increase in bFGF expression in astrocytes leads to enhanced secretion of this peptide and to long‐term plasticity in DA neurons. To study directly the effects of astrocytic expression of bFGF on DA neurons, we established a cell‐culture model of mesencephalic astrocytes and DA neurons. Immunolabelling showed that even in the absence of a pharmacological stimulus, the majority of mesencephalic astrocytes in culture express bFGF at a nuclear level. Arguing against the idea that bFGF was secreted, bFGF was undetectable in the extracellular medium (below 10 pg/mL). However, supplementing culture medium with exogenous bFGF at standard concentrations (20 ng/mL) led to a dramatic change in the morphology of astrocytes, increased spontaneous DA release, and inhibited synapse formation by individual DA neurons. RNA interference (siRNA) against bFGF mRNA, caused a reduction in DA release but produced no change in synaptic development. Together these data demonstrate that under basal conditions (in the absence of a pharmacological stimulus such as amphetamine) bFGF is not secreted even though there is abundant nuclear expression in astrocytes. The effects of bFGF seen here on DA neurons are thus likely to be mediated through more indirect glial–neuronal interactions, leading to enhanced DA release without a necessary change in synapse number.
The sound of actions as reflected by mismatch negativity: rapid activation of cortical sensory–motor networks by sounds associated with finger and tongue movements
Authors: Hauk O. , Shtyrov Y. , Pulvermüller F.
Published: February 2006

In order to explore the activation dynamics of the human action recognition system, we investigated electrophysiological distinctions between the brain responses to sounds produced by human finger and tongue movements. Of special interest were the questions of how early these differences may occur, and whether the neural activation at the early stages of processing involves cortical motor representations related to the generation of these sounds. For this purpose we employed a high‐density EEG set‐up and recorded mismatch negativity (MMN) using a recently developed novel multideviant paradigm which allows acquisition of a high number of trials within a given time period. Deviant stimuli were naturally recorded finger and tongue clicks, as well as control stimuli with similar physical features but without the clear action associations (this was tested in a separate behavioural experiment). Both natural stimuli produced larger MMNs than their respective control stimuli at ∼ 100 ms, indicating activation of memory traces for familiar action‐related sounds. Furthermore, MMN topography at this latency differed between the brain responses to the natural finger and natural tongue sounds. Source estimation revealed the strongest sources for finger sounds in centrolateral areas of the left hemisphere, suggesting that hearing a sound related to finger actions evokes activity in motor areas associated with the dominant hand. Furthermore, tongue sounds produced activation in more inferior brain areas. Our data suggest that motor areas in the human brain are part of neural systems subserving the early automatic recognition of action‐related sounds.
Electrophysiological and morphological characteristics of GABAergic respiratory neurons in the mouse pre‐Bötzinger complex
Authors: Kuwana Shun‐ichi , Tsunekawa Naoko , Yanagawa Yuchio , Okada Yasumasa , Kuribayashi Junya , Obata Kunihiko
Published: February 2006

The characteristics of GABAergic neurons involved in respiratory control have not been fully understood because identification of GABAergic neurons has so far been difficult in living tissues. In the present in vitro study, we succeeded in analysing the electrophysiological as well as morphological characteristics of GABAergic neurons in the pre‐Bötzinger complex. We used 67‐kDa isoform of glutamic acid decarboxylase‐green fluorescence protein (GAD67‐GFP) (Δneo) knock‐in (GAD67GFP/+) mice, which enabled us to identify GABAergic neurons in living tissues. We prepared medullary transverse slices that contained the pre‐Bötzinger complex from these neonatal mice. The fluorescence intensity of the pre‐Bötzinger complex region was relatively high among areas of the ventral medulla. Activities of GFP‐positive neurons in the pre‐Bötzinger complex were recorded in a perforated whole‐cell patch‐clamp mode. Six of 32 GFP‐positive neurons were respiratory and the remaining 26 neurons were non‐respiratory; the respiratory neurons were exclusively inspiratory, receiving excitatory post‐synaptic potentials during the inspiratory phase. In addition, six inspiratory and one expiratory neuron of 30 GFP‐negative neurons were recorded in the pre‐Bötzinger complex. GFP‐positive inspiratory neurons showed high membrane resistance and mild adaptation of spike frequency in response to depolarizing current pulses. GFP‐positive inspiratory neurons had bipolar, triangular or crescent‐shaped somata and GFP‐negative inspiratory neurons had multipolar‐shaped somata. The somata of GFP‐positive inspiratory neurons were smaller than those of GFP‐negative inspiratory neurons. We suggest that GABAergic inhibition not by expiratory neurons but by inspiratory neurons that have particular electrophysiological and morphological properties is involved in the respiratory neuronal network of the pre‐Bötzinger complex.
Dietary phytoestrogens improve stroke outcome after transient focal cerebral ischemia in rats
Authors: Burguete María C. , Torregrosa Pérez‐Asensio Germán, Fernando J. , Castelló‐Ruiz María , Salom Gil Juan B., José V. , Alborch Enrique
Published: February 2006

As phytoestrogens are postulated as being neuroprotectants, we assessed the hypothesis that dietary isoflavone‐type phytoestrogens are neuroprotective against ischemic stroke. Transient focal cerebral ischemia (90 min) was induced by middle cerebral artery occlusion (MCAO) following the intraluminal thread technique, both in rats fed with soy‐based diet and in rats fed with isoflavone‐free diet. Cerebro‐cortical laser‐Doppler flow (cortical perfusion, CP), arterial blood pressure, core temperature,PaO2,PaCO2, pH and glycemia were measured before, during and after MCAO. Neurological examination and infarct volume measurements were carried out 3 days after the ischemic insult. Dietary isoflavones (both glycosides and aglycones) were measured by high‐performance liquide chromatography. Neither pre‐ischemic, intra‐ischemic nor post‐ischemic CP values were significantly different between the soy‐based diet and the isoflavone‐free diet groups. Animals fed with the soy‐based diet showed an infarct volume of 122 ± 20.2 mm3(19 ± 3.3% of the whole ipsilateral hemisphere volume). In animals fed with the isoflavone‐free diet the mean infarct volume was significantly higher, 191 ± 26.7 mm3(28 ± 4.1%,P < 0.05). Neurological examination revealed significantly higher impairment in the isoflavone‐free diet group compared with the soy‐based diet group (3.3 ± 0.5 vs. 1.9 ± 0.5,P < 0.05). These results demonstrate that dietary isoflavones improve stroke outcome after transient focal cerebral ischemia in such a way that a higher dietary isoflavone content results in a lower infarct volume and a better neurological status.
Development of contralateral and ipsilateral frequency representations in ferret primary auditory cortex
Authors: Mrsic‐Flogel Thomas D. , Versnel Huib , King Andrew J.
Published: February 2006

Little is known about the maturation of functional maps in the primary auditory cortex (A1) after the onset of sensory experience. We used intrinsic signal imaging to examine the development of the tonotopic organization of ferret A1 with respect to contralateral and ipsilateral tone stimulation. Sound‐evoked responses were recorded as early as postnatal day (P) 33, a few days after hearing onset. From P36 onwards, pure tone stimuli evoked restricted, tonotopically organized patches of activity. There was an age‐dependent increase in the cortical area representing each octave, with a disproportionate expansion of cortical territory representing frequencies > 4 kHz after P60. Similar tonotopic maps were observed following stimulation of the contralateral and ipsilateral ears. During the first few weeks following hearing onset, no differences were found in the area of cortical activation or in the magnitude of the optical responses evoked by stimulation of each ear. In older animals, however, contralateral stimuli evoked stronger responses and activated a larger A1 area than ipsilateral stimuli. Our findings indicate that neither the tonotopic organization nor the representation of inputs from each ear reach maturity until approximately 1 month after hearing onset. These results have important implications for cortical signal processing in juvenile animals.
Monitoring the European pine sawfly with pheromone traps in maturing Scots pine stands
Authors: Lyytikäinen‐Saarenmaa Päivi , Varama Martti , Anderbrant Olle , Kukkola Mikko , Kokkonen Anna‐Maija , Hedenström Erik , Högberg Hans‐Erik
Published: February 2006

Abstract 

During 1989–93, field studies were conducted in Finland to develop a method based on pheromone traps to monitor and forecast population levels of the European pine sawfly (Neodiprion sertifer Geoffr.) and tree defoliation.

Three traps per site were baited with 100 µg of the N. sertifer sex pheromone, the acetate ester of (2S,3S,7S)‐3,7‐dimethyl‐2‐pentadecanol (diprionol), in maturing pine stands in southern and central Finland. In addition, three different dosages (1, 10 and 100 µg) of the pheromone were tested in 1991–92.

The highest number of males was observed in traps baited with the highest dose. On average, there was a 10‐fold increase in trap catch between lure doses.

Density of overwintering eggs was used to evaluate the effectiveness of pheromone traps in predicting sawfly populations. The proportion of healthy overwintering eggs was determined each year. A model based on the number of current shoots on sample trees, diameter at breast height and tree height was formulated to estimate eggs per hectare.

Linear regression analysis produced high coefficients of determination between number of males in traps and density of total eggs in the subsequent generation, when populations were at peak densities. The relationships were not significant for low population densities. The results indicate a risk of moderate defoliation when the seasonal trap catch is 800–1000 males per trap or higher.
Synthetic amides toxic to the leaf‐cutting ant Atta sexdens rubropilosa L. and its symbiotic fungus
Authors: Pagnocca F. C. , Victor S. R. , Bueno F. C. , Crisóstomo F. R. , Castral T. C. , Fernandes J. B. , Corrêa A. G. , Bueno O. C. , Bacci M. , Hebling M. J. A. , Vieira P. C. , Da Silva M. F. G. F.
Published: February 2006

Nine synthetic amides similar to natural N‐piperidine‐3‐(4,5‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N‐pyrrolidine‐3‐(4,5‐methylenedyoxiphenyl)‐2‐(E)‐propenamide were synthesized and identified by their spectroscopic data.

The toxicity of these synthetic amides to the Atta sexdens rubropilosa workers and the antifungal activity against Leucoagaricus gongylophorus, the symbiotic fungus of the leaf‐cutting ants, were determined.

Workers ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls for N‐pyrrolidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N‐benzyl‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at a concentration of 100 µg/mL.

The completely inhibition (100%) of the fungal growth was observed with N‐piperidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N,N‐diethyl‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at concentrations of 50 and 100 µg/mL and N‐pirrolidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at a concentration of 100 µg/mL.

The possibility of controlling these insects in the future using synthetic piperamides that can simultaneously target both organisms is discussed.
Fishing down the deep
Authors: Morato Telmo , Watson Reg , Pitcher Tony J. , Pauly Daniel
Published: February 2006

Global landings of demersal marine fishes are demonstrated to have shifted to deeper water species over the last 50 years. Our analysis suggests deep‐water fish stocks may be at serious risk of depletion, as their life histories render them highly vulnerable to overfishing with little resilience to over‐exploitation. Deep‐sea fisheries are exploiting the last refuges for commercial fish species and should not be seen as a replacement for declining resources in shallower waters. Instead, deep‐water habitats are new candidates for conservation.
‘As He Refined the Language’: Dryden's Task as a Translator
Authors: Currell David
Published: February 2006

This essay was runner‐up in the 2005Literature CompassGraduate Essay Prize, Seventeenth Century Section.

The essay surveys Dryden's prose works, and his career as translator from Westminster School toFables Ancient and Modern, in order to show his conception of literary translation as a tool to elevate, enrich and refine the English language. Dryden had a heavy investment in the idea oftranslatio studii, the translation of the arts between successive cultures, from Ancient Greece to Restoration England, and perceived himself as a crucial agent in this historical progress. But accompanying the premise of England's inheritance of cultural eminence is a veneration for Latin which makes classicising via translation a crucial task for England's leading person of letters; especially as hopes of a British Academy under royal patronage faded. Dryden found ways to advance this aim under all his three theorised modes of translation: metaphrase (word‐for‐word), imitation (loose rewriting) and paraphrase (a middle path). Finally, at the end of his life, he discusses the English language as if his project had attained some success, and was an appropriate medium in which to set down Latin classics beside its own classics as peers.
KERALA: A UNION ALTERNATIVE TO CORPORATE GLOBALIZATION
Authors: Reynolds David , Harilal K. N.
Published: February 2006

Many progressive unionists in the U.S. advocate for international solidarity and active support for strong labor movements in the developing world. Fortunately, a more unionized global future is not simply an abstraction but is already a reality in some developing countries. On the surface, the poor Indian state of Kerala ought to reveal shantytowns and other stark signs of poverty common among the poorest areas of the world. Yet, because of the state's strong labor movement, the population enjoys basic standard of living indicators far closer to the U.S. than to wealthier parts of India. This article examines this labor movement, its past successes, and the innovative strategies that the Keralan Left is using to address the powerful pressures caused by corporate globalization. The Kerala experience offers instructive lessons not simply for the developing world, but for Americans who wish to take participatory democracy seriously.
BUILDING A MOVEMENT: REVITALIZING LABOR IN MIAMI1
Authors: Nissen Bruce , Russo Monica
Published: February 2006

This article examines Miami's demographic, economic, and political context within which the local labor movement operates, and profiles the local labor movement. It also looks at the past decade's modestly successful efforts to build the local “social justice infrastructure” to provide a supportive environment for organizing workers: faith‐based worker rights organizations, working‐class community organizing projects, labor‐community coalition organizations, immigrant leadership development and civic participation organizations, and research capacity. Despite progress, much remains to be done, and the article reviews the efforts to reinforce the infrastructure, focus coalition work, and to stimulate and sustain national union organizing investment in the area. Opportunities and dangers in new approaches to move forward are outlined.
Reflex activation of rat fusimotor neurons by body surface cooling, and its dependence on the medullary raphé
Authors: Tanaka Mutsumi , Owens Neil C. , Nagashima Kei , Kanosue Kazuyuki , McAllen Robin M.
Published: February 2006

The nature of muscle efferent fibre activation during whole body cooling was investigated in urethane‐anaesthetized rats. Multiunit efferent activity to the gastrocnemius muscle was detected when the trunk skin was cooled by a water‐perfused jacket to below 36.0 ± 0.7°C. That efferent activity was not blocked by hexamethonium (50 mg kg−1, i.v.) and was not associated with movement or electromyographic activity. Cold‐induced efferent activity enhanced the discharge of afferent filaments from the isotonically stretched gastrocnemius muscle, demonstrating that it was fusimotor. Fusimotor neurons were activated by falls in trunk skin temperature, but that activity ceased when the skin was rewarmed, regardless of how low core temperature had fallen. While low core temperature alone was ineffective, a high core temperature could inhibit the fusimotor response to skin cooling. Fusimotor activation by skin cooling was often accompanied by desynchronization of the frontal electroencephalogram (EEG), but was not a simple consequence of cortical arousal, in that warming the scrotum desynchronized the EEG without activating fusimotor fibres. Inhibition of neurons in the rostral medullary raphé by microinjections of glycine (0.5 m, 120–180 nl) reduced the fusimotor response to skin cooling by 95 ± 3%, but did not prevent the EEG response. These results are interpreted as showing a novel thermoregulatory reflex that is triggered by cold exposure. It may underlie the increased muscle tone that precedes overt shivering, and could also serve to amplify shivering. Like several other cold‐defence responses, this reflex depends upon neurons in the rostral medullary raphé.
Mediation of late excitation from human hand muscles via parallel group II spinal and group I transcortical pathways
Authors: Lourenço George , Iglesias Caroline , Cavallari Paolo , Pierrot‐Deseilligny Emmanuel , Marchand‐Pauvert Véronique
Published: February 2006

This study addresses the question of the origin of the long‐latency responses evoked in flexors in the forearm by afferents from human hand muscles. The effects of electrical stimuli to the ulnar nerve at wrist level were assessed in healthy subjects using post‐stimulus time histograms for flexor digitorum superficialis and flexor carpi radialis (FCR) single motor units (eight subjects) and the modulation of the ongoing rectified FCR EMG (19 subjects). Ulnar stimulation evoked four successive peaks of heteronymous excitation that were not produced by purely cutaneous stimuli: a monosynaptic Ia excitation, a second group I excitation attributable to a propriospinally mediated effect, and two late peaks. The first long‐latency excitation occurred 8–13 ms after monosynaptic latency and had a high‐threshold (1.2–1.5 × motor threshold). When the conditioning stimulation was applied at a more distal site and when the ulnar nerve was cooled, the latency of this late excitation increased more than the latency of monosynaptic Ia excitation. This late response was not evoked in the contralateral FCR of one patient with bilateral corticospinal projections to FCR motoneurones. Finally, oral tizanidine suppressed the long‐latency high‐threshold excitation but not the early low‐threshold group I responses. These results suggest that the late high‐threshold response is mediated through a spinal pathway fed by muscle spindle group II afferents. The second long‐latency excitation, less frequently observed (but probably underestimated), occurred 16–18 ms after monosynaptic latency, had a low threshold indicating a group I effect, and was not suppressed by tizanidine. It is suggested that this latest excitation involves a transcortical pathway.
Prenatal exposure to excess testosterone modifies the developmental trajectory of the insulin‐like growth factor system in female sheep
Authors: Crespi Erica J. , Steckler Teresa L. , MohanKumar Puliyur S. , Padmanabhan Vasantha
Published: February 2006

Experimental elevation of maternal testosterone (T) from 30 to 90 days of gestation leads to intrauterine growth retardation (IUGR) and increased prepubertal growth rate in female lambs. This study tested the hypothesis that prenatal T treatment during mid‐gestation alters the trajectory of the fetal insulin‐like growth factor (IGF)–insulin‐like growth factor binding protein (IGFBP) system to promote IUGR and subsequent postnatal catch‐up growth in female lambs. Plasma IGF‐I and IGFBPs were measured by radioimmunoassay and Western ligand blot, respectively, on 65, 90 and 140 days (d) of gestation, at birth, ∼5 months (prepubertal, the catch‐up growth period), and ∼9.5 months (postpubertal). Northern blot analysis was used to measure hepatic mRNA content of IGF system components during fetal stages. At fetal 65 d, plasma protein and hepatic mRNA content of IGFBP‐1, an inhibitor of IGF bioactivity, was elevated in prenatal T‐treated fetuses although body weight did not differ. There was a transient increase in plasma IGF‐I and IGFBP‐3 concentrations at fetal 90 d in prenatal T‐treated fetuses. Hepatic IGF‐I mRNA and plasma IGFBP‐3 content were reduced by 140 d when body weight was reduced in prenatal T‐treated fetuses. Plasma IGFBP‐2 content was significantly reduced in prenatal T‐treated newborns, but by 4 months these females had significantly higher circulating IGF‐I and IGFBP‐3 concentrations and faster growth rates than control females. After puberty, plasma IGF‐I remained elevated in prenatal T‐treated females. These findings provide evidence that prenatal T excess programmes the developmental trajectory of the IGF/IGFBP system in female sheep to reduce IGF bioavailability during IUGR and increase IGF bioavailability during prepubertal catch‐up growth.
A Protein Farnesyltransferase Inhibitor Ameliorates Disease in a Mouse Model of Progeria
Authors: Fong Loren G. , Frost David , Meta Margarita , Qiao Xin , Yang Shao H. , Coffinier Catherine , Young Stephen G.
Published: February 2006

Progerias are rare genetic diseases characterized by premature aging. Several progeroid disorders are caused by mutations that lead to the accumulation of a lipid-modified (farnesylated) form of prelamin A, a protein that contributes to the structural scaffolding for the cell nucleus. In progeria, the accumulation of farnesyl–prelamin A disrupts this scaffolding, leading to misshapen nuclei. Previous studies have shown that farnesyltransferase inhibitors (FTIs) reverse this cellular abnormality. We tested the efficacy of an FTI (ABT-100) in
Zmpste24
-deficient mice, a mouse model of progeria. The FTI-treated mice exhibited improved body weight, grip strength, bone integrity, and percent survival at 20 weeks of age. These results suggest that FTIs may have beneficial effects in humans with progeria.