bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic relationships of the African genera Alestes and Brycinus (Teleostei, Characiformes, Alestidae)
Authors: Murray Alison M , Stewart Kathlyn M
Published: January 2003

The family Alestidae (also referred to as the African Characidae) comprises the African dwarf forms ("Petersiini") and the genera Alestes, Brycinus, Bryconaethiops, and Hydrocynus. Although several authors have presented characters to support the monophyly of the family, a cladistic analysis of the group has not been published. Furthermore, the interrelationships of the constituent groups are the subject of some controversy. A cladistic analysis of the Alestidae is presented, including characters to support the monophyly of the family. The results of this study indicate that several species should be removed from the genus Brycinus, that Hydrocynus is the sister group of Alestes s.str. (containing only five species), and that the dwarf alestids ("Petersiini") do not form a monophyletic group.
Seasonal migration of Columbia spotted frogs (Rana luteiventris) among complementary resources in a high mountain basin
Authors: Pilliod David S , Peterson Charles R , Ritson Peter I
Published: January 2003

Information on how animals partition their activities and travel among complementary resources, such as breeding or overwintering habitats, is needed for species conservation. In a mountain basin at 2500 m elevation in central Idaho, we studied the habitat use and movement patterns of 736 marked and 87 radio-tagged Columbia spotted frogs (Rana luteiventris) from 1995 to 1998. The goals of this study were to (i) identify and characterize R. luteiventris breeding, summer foraging, and overwintering habitats, (ii) describe the movement patterns of juvenile, male, and female R. luteiventris among these resources, and (iii) determine migration routes. Juvenile and adult R. luteiventris occupied a variety of widely distributed wetlands from late June to September. On average, 132% of juvenile, 611% of male, and 1651% of female frogs moved from breeding ponds to summer habitats. Migratory males remained within 200 m of the breeding sites, whereas females traveled up to 1030 m to reach summer habitats. From late August through September, frogs migrated to deep (>3 m) lakes to overwinter. Frog migrations occurred quickly and often followed shortest-distance travel routes through dry, open forest even when stream corridors were available nearby. This study exemplifies the need to protect both complementary resources and the corridors connecting these anuran habitats.
Impact of exposure to a simulated predator (Mergus merganser) on the activity of juvenile Atlantic salmon (Salmo salar) in a natural environment
Authors: Dionne Mélanie , Dodson Julian J
Published: January 2003

Some laboratory studies suggest that the presence of predators influences the short-term behaviour of juvenile Atlantic salmon. However, few studies have been conducted in the natural environment to confirm these observations and to document how biological and environmental factors influence the behaviour of fish faced with a predator. Of the many potential predators of juvenile Atlantic salmon, Salmo salar, the common merganser, Mergus merganser, is a major one. This study was designed to investigate the immediate and short-term impact of exposure to a simulated avian predator on the activity of juvenile Atlantic salmon in their natural habitat. The influence of riverbed sediment grain size, a major determinant of habitat choice in salmon, and body size of juvenile salmon on the nature and intensity of their response to the predator was also investigated. Observations were made before and after exposure to a model of M. merganser in three situations: (1) fry (young salmon during their first summer of life) on fine sediment, (2) fry on coarse sediment, and (3) parr (young salmon during their second or third summer of life) on coarse sediment. Observations were also made on fry exposed to a harmless floating stimulus to evaluate if the decoys were perceived as threat. Following exposure, the feeding rate of juvenile salmon decreased by 2539% and the moving rate increased by 123386%. Sediment grain size influenced the nature of the immediate response of juvenile salmon, while body size influenced the intensity of the moving response. Parr moved significantly more than fry after exposure to the simulated predator.
Swift fox (Vulpes velox) home-range dispersion patterns in southeastern Wyoming
Authors: Olson Travis L , Lindzey Frederick G
Published: January 2003

We monitored dispersion patterns of swift foxes (Vulpes velox) for 3 years in shrub-grassland habitats on the margin of the species' geographic range near Medicine Bow, Wyoming. Annual home-range size was 18.6 ± 1.6 km2 (mean ± SE, n = 13) and was similar to home-range estimates reported in other studies conducted within grassland habitats in other portions of the species' geographic range. Male home ranges were larger than those of their mates during pup-rearing periods (P < 0.04) but were similar in size during the dispersal period. The home ranges of both sexes were smallest during the pup-rearing period. The degree of home-range overlap for mates (biological periods combined) was high (range = 27.4100%, mean ± SE = 70.8 ± 0.03%, n = 26 pairs) but was minimal between adjacent pairs (range = 0.236%, mean ± SE = 11.9 ± 2.4%, n = 10 pairs), suggesting territorial behavior. Occupied home ranges were distributed similarly each year despite one or both pair members often being new. Swift fox home-range size varied seasonally, and home-range dispersion patterns appeared to be influenced by the presence of other fox pairs and the recent use of an area by other swift foxes.
Pituitary adenylate cyclase-activating peptide and lung-liquid reabsorption in vitro by lungs from fetal guinea-pigs
Authors: Li-Pak-Tong B , Ram S , Perks A M
Published: January 2003

Pituitary adenylate cyclase-activating peptide (PACAP) is present in the lungs, notably in their internal neuroendocrine system; however, its use is not clear. It was investigated for its possible ability to cause lung-liquid reabsorption around birth. Lungs from 31 late-term fetal guinea-pigs (at 60 ± 2 days of gestation) were supported in vitro for 3 h; lung-liquid movements were monitored by a dye-dilution method. Untreated control preparations (n = 9) produced fluid at 1.85 ± 0.40 mL·kg1 body mass·h1 (mean ± SD), with no significant change (ANOVA, regression analysis). Those given 108 M PACAP in the middle hour turned to reabsorption (n = 3) or reduced production markedly (n = 3) (average fall 84.4 ± 5.4%; significant at P < 0.0010.0005); effects continued and increased after the PACAP was removed. Preparations given 109 M PACAP reacted similarly, but there was partial recovery after treatment (five reabsorbed, four reduced production; average fall 91.4 ± 14.3%; significant at P < 0.010.0005). Preparations given 1010 M PACAP all reduced production, with partial recovery (average fall 43.5 ± 8.2%; significant at P < 0.0050.0005). Preparations given 1011 M PACAP showed little or no effect. The linear log doseresponse curve became maximal at 109 M (r2 = 0.98; theoretical threshold 1013 M). The results increase the likelihood that the neuroendocrine system is important in lung-liquid reabsorption, and suggest that PACAP could combine its relaxation of airways with lung-liquid removal, and therefore aid the first attempts of the newborn to breathe.
Seasonal changes in territory use by red squirrels, Tamiasciurus hudsonicus, and responses to food augmentation
Authors: Vlasman Kara L , Fryxell John M
Published: January 2003

Traditionally, the importance of food availability and intruder pressure on habitat use have been investigated through their influences on territory size. Food-augmentation studies are more prevalent; however, they are potentially confounded by the indirect effect of conspecific attraction to local food additions. Frequent ambiguous results may be attributed to the scale of investigation. Furthermore, such investigations have not considered potential seasonal influences. In this study, controlled experimental manipulations of food availability and conspecific density were performed within red squirrel (Tamiasciurus hudsonicus) territories in Algonquin Park, Ontario, to tease apart the relative importance of direct and indirect effects of food augmentation. Effects were investigated at two levels of scale, using territory size and giving-up densities (GUDs) within activity locations as response variables. Augmenting food, with or without simultaneously removing conspecifics, did not influence territory size. However, territory size decreased in control and treatment groups following manipulations, which is suggestive of seasonal influences associated with caching behaviour and midden defence. Despite overwhelming seasonal influences, GUDs were more sensitive to treatments, revealing that competitors had a greater influence on habitat use than the direct effect of food addition. Ambiguous results of previous studies may due to the use of territory-size estimators that are insensitive to responses occurring at smaller scales.
A PROPOSAL TO RESOLVE THE BLACK HOLE INFORMATION PARADOX
Authors: MATHUR SAMIR D.
Published: January 2003

The entropy and information puzzles arising from black holes cannot be resolved if quantum gravity effects remain confined to a microscopic scale. We use concrete computations in nonperturbative string theory to argue for three kinds of nonlocal effects that operate over macroscopic distances. These effects arise when we make a bound state of a large number of branes, and occur at the correct scale to resolve the paradoxes associated with black holes.
A MISSION TO TEST THE PIONEER ANOMALY
Authors: ANDERSON JOHN D. , TURYSHEV SLAVA G. , NIETO MICHAEL MARTIN
Published: January 2003

Analysis of the radio tracking data from the Pioneer 10/11 spacecraft has consistently indicated the presence of an anomalous small Doppler frequency drift. The drift can be interpreted as being due to a constant acceleration of aP = (8.74 ± 1.33) × 10-8 cm/s 2 directed towards the Sun. Although it is suspected that there is a systematic origin to the effect, none has been found. The nature of this anomaly has become of growing interest in the fields of relativistic cosmology, astro- and gravitational physics as well as in the areas of spacecraft design and high-precision navigation. We present a concept for a designated deep-space mission to test the discovered anomaly. A number of critical requirements and design considerations for such a mission are outlined and addressed.
GRAVITATIONAL RAINBOW OF MASSIVE PARTICLES
Authors: ACCIOLY ANTONIO
Published: January 2003

Photon propagation is non-dispersive within the context of semiclassical general relativity. What about the remaining massless particles? It can be shown that at the tree level the scattering of massless particles of spin 0, 1/2, 1 or whatever by a static gravitational field generated by a localized source such as the Sun, treated as an external field, is non-dispersive as well. It is amazing, however, that massive particles, regardless of whether they have integral or half-integral spin, experience an energy-dependent gravitational deflection. Therefore, semiclassical general relativity and gravitational rainbows of massive particles can coexist without conflict. We address this issue in this essay.
SPACETIME FOAM
Authors: NG Y. JACK
Published: January 2003

Spacetime is composed of a fluctuating arrangement of bubbles or loops called spacetime foam, or quantum foam. We use the holographic principle to deduce its structure, and show that the result is consistent with gedanken experiments involving spacetime measurements. We propose to use laser-based atom interferometry techniques to look for spacetime fluctuations. Our analysis makes it clear that the physics of quantum foam is inextricably linked to that of black holes. A negative experimental result, therefore, might have non-trivial ramifications for semiclassical gravity and black hole physics.
VACUUM SELECTION BY INFLATION AS THE ORIGIN OF THE DARK ENERGY
Authors: YOKOYAMA JUN'ICHI
Published: January 2003

I propose a new mechanism to account for the observed tiny but finite dark energy in terms of a non-Abelian Higgs theory, which has infinitely many perturbative vacua characterized by a winding number, in the framework of inflationary cosmology. Inflation homogenizes field configuration and practically realizes a perturbative vacuum with vanishing winding number, which is expressed by a superposition of eigenstates of the Hamiltonian with different vacuum energy density. As a result, we naturally find a nonvanishing vacuum energy density with fairly large probability, under the assumption that the cosmological constant vanishes in some vacuum state. Since the predicted magnitude of dark energy is exponentially suppressed by the instanton action, we can fit observation without introducing any tiny parameters.
CLASSIFICATIONS OF KANTOWSKI–SACHS, BIANCHI TYPES I AND III SPACETIMES ACCORDING TO RICCI COLLINEATIONS
Authors: CAMCI UĞUR , YAVUZ İLHAMİ
Published: January 2003

The Ricci collineation classifications of Kantowski–Sachs, Bianchi types I and III spacetimes are studied according to their degenerate and non-degenerate Ricci tensor. When the Ricci tensor is degenerate, the special cases are classified and it is shown that there are many cases of Ricci collineations (RCs) with infinite number of degrees of freedom, and the group of RCs is ten-dimensional in some spacial cases. Furthermore, it is found that when the Ricci tensor is non-degenerate, the group of RCs is finite-dimensional, and we have only either four which coincides with the isometries or six proper RCs in addition to the four isometries.
DIRAC EQUATION IN SPACETIMES WITH NON-METRICITY AND TORSION
Authors: ADAK M. , DERELI T. , RYDER L. H.
Published: January 2003

Dirac equation is written in a non-Riemannian spacetime with torsion and non-metricity by lifting the connection from the tangent bundle to the spinor bundle over spacetime. Foldy–Wouthuysen transformation of the Dirac equation in a Schwarzschild background spacetime is considered and it is shown that both the torsion and non-metricity couples to the momentum and spin of a massive, spinning particle. However, the effects are small to be observationally significant.
ON SOME GRAVITOMAGNETIC SPIN–SPIN EFFECTS FOR ASTRONOMICAL BODIES
Authors: IORIO LORENZO
Published: January 2003

In this paper we look at the gravitational spin–spin interaction between macroscopic astronomical bodies. In particular, we calculate their post-Newtonian orbital effects of order [Formula: see text] on the trajectory of a spinning particle with proper angular momentum s moving in the external gravitomagnetic field generated by a central spinning mass with proper angular momentum J. It turns out that, at order [Formula: see text] in the orbiter's eccentricity, the eccentricity the pericenter and the mean anomaly rates of the moving particle are affected by long-term harmonic effects. If, on one hand, they are undetectable in the Solar System, on the other, maybe in an astrophysical context like that of the binary millisecond pulsars there will be some hopes of measuring them in the future, provided that substantial improvements in the accuracy of the detection of the periastron rate will occur.
Magnetic Resonance Image-Guided Transcatheter Closure of Atrial Septal Defects
Authors: Rickers Carsten , Jerosch-Herold Michael , Hu Xudong , Murthy Naveen , Wang Xiaoen , Kong Huafu , Seethamraju Ravi Teja , Weil Jochen , Wilke Norbert M.
Published: January 2003

Background—

Recent developments in cardiac MRI have extended the potential spectrum of diagnostic and interventional applications. The purpose of this study was to test the ability of MRI to perform transcatheter closures of secundum type atrial septal defects (ASD) and to assess ASD size and changes in right cardiac chamber volumes in the same investigation.

Methods and Results—

In 7 domestic swine (body weight, 38±13 kg), an ASD (Q
p
:Q
s
=1.7±0.2) was created percutaneously by balloon dilation of the fossa ovalis. The ASD was imaged and sized by both conventional radiography and MRI. High-resolution MRI of the ASD diameters correlated well with postmortem examination (
r
=0.97). Under real-time MR fluoroscopy, the introducer sheath was tracked toward the left atrium with the use of novel miniature MR guide wires. The defect was then closed with an Amplatzer Septal Occluder. In all animals, it was possible to track and interactively control the position of the guide wire within the vessels and the heart, including the successful deployment of the Amplatzer Septal Occluder. Right atrial and ventricular volumes were calculated before and after the intervention by using cine-MRI. Both volumes were found to be significantly reduced after ASD closure (
P
<0.005).

Conclusions—

These in vivo studies demonstrate that catheter tracking and ASD device closure can be performed under real-time MRI guidance with the use of intravascular antenna guide wires. High-resolution imaging allows accurate determination of ASD size before the intervention, and immediate treatment effects such as changes in right cardiac volumes can also be measured.
Differential Role of K
ATP
Channels Activated by Conjugated Estrogens in the Regulation of Myocardial and Coronary Protective Effects
Authors: Lee Tsung-Ming , Chou Tsai-Fwu , Tsai Chang-Her
Published: January 2003

Background—

We have demonstrated that estrogen can reduce myocardial injury in ischemia-reperfusion via activation of ATP-sensitive potassium (K
ATP
) channels. We sought to determine whether the protective effect of estrogen extends to epicardial coronary artery with attenuated vasoconstriction in patients after angioplasty by activation of such channels.

Methods and Results—

The study was designed to prospectively investigate 41 consecutive patients scheduled for elective coronary angioplasty. Pretreatment with estrogen limited myocardial ischemia during coronary occlusion and attenuated postangioplasty coronary vasoconstriction at the dilated and distal segments. An inhibitor of K
ATP
channels, glibenclamide, did not affect coronary vasomotor response, although it abolished the beneficial effect of estrogen on myocardial ischemia. Patients to whom estrogen was administered after the second balloon deflation experienced a similar magnitude of myocardial ischemia as controls but showed significantly attenuated vasoconstriction compared with controls (
P
=0.0001). Endothelin-1 levels from the great cardiac vein rose significantly from 1.9±0.4 to 3.1±0.6 pg/mL (
P
=0.001) 15 minutes after angioplasty in the control group; this was attenuated after estrogen was administered. Significant correlation was found between the changes in coronary vasomotion of the dilated segment and endothelin-1 levels (
r
=0.65,
P
<0.0001).

Conclusions—

These results demonstrate that estrogen is protective against both myocardial ischemia and coronary vasoconstriction through different mechanisms. The myocardial effect of estrogen was abolished by glibenclamide, which suggests that the cardioprotective effect of estrogen may result from activation of K
ATP
channels. In contrast, estrogen-induced attenuated vasoconstriction is associated with an attenuated release of endothelin-1, independent of K
ATP
activation.
Doxazosin Induces Apoptosis in Cardiomyocytes Cultured In Vitro by a Mechanism That Is Independent of α
1
-Adrenergic Blockade
Authors: González-Juanatey José R. , Iglesias María J. , Alcaide Carlos , Piñeiro Roberto , Lago Francisca
Published: January 2003

Background—

The α
1
-adrenoceptor–blocking antihypertensive doxazosin has been associated with increased risk of heart failure and is known to induce prostate cell apoptosis. We hypothesized that it might also induce apoptosis in cardiomyocytes.

Methods and Results—

Hoechst dye vital staining and flow cytometry provided evidence that doxazosin induced apoptosis time- and dose-dependently in cardiomyocytes of the HL-1 cell line. TUNEL assays and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) viability test confirmed that doxazosin induced DNA damage and cell death in these cells. MTT tests showed that doxazosin treatment decreased cell viability in primary cultures of neonatal rat cardiomyocytes, and Hoechst dye vital staining demonstrated doxazosin-induced apoptosis in primary cultures of human adult cardiomyocytes. The proapoptotic effect of doxazosin on cardiomyocytes seems not to depend on α
1
blockade, because it was not modified by cotreatment with α- or β-adrenergic agonists or with the irreversible α
1
-blocker phenoxybenzamine and because doxazosin also decreased the viability of NIH 3T3 cells, which lack α
1
-adrenoceptors. It also does not involve calcineurin, being unaffected by the presence of the calcineurin inhibitors cyclosporin A and FK506. Three other α
1
-blockers were also investigated; prazosin was proapoptotic, like doxazosin, but 5-methylurapidil and terazosin were not.

Conclusions—

The α
1
-blockers doxazosin and prazosin induce the apoptosis of cardiomyocytes cultured in vitro by a mechanism that is independent of α
1
blockade and calcineurin.
Truncated Estrogen Receptor α 46-kDa Isoform in Human Endothelial Cells
Authors: Figtree Gemma A. , McDonald Denise , Watkins Hugh , Channon Keith M.
Published: January 2003

Background—

Estrogen acutely activates endothelial nitric oxide synthase (eNOS). However, the identity of the receptors involved in this rapid response remains unclear.

Methods and Results—

We detected an estrogen receptor α (ERα) transcript in human endothelial cells that encodes a truncated 46-kDa ERα (Δ1a-hERα-46). A corresponding 46-kDa ERα protein was identified in endothelial cell lysates. Transfection of cDNAs encoding the full-length ERα (ERα-66) and Δ1a-hERα-46 resulted in appropriately sized recombinant proteins identified by anti-ERα antibodies. Confocal microscopy revealed that a proportion of both ERα-66 and hERα-46 was localized outside the nucleus and mediated specific cell-surface binding of estrogen as assessed by FITC-conjugated, BSA-estrogen binding studies. Both ERα isoforms colocalized with eNOS and mediated acute activation of eNOS in response to estrogen stimulation. However, estrogen-stimulated transcriptional activation mediated by Δ1a-hERα-46 was much less than with ERα-66. Furthermore, Δ1a-hERα-46 inhibited classical hERα-66–mediated transcriptional activation in a dominant-negative fashion.

Conclusions—

These findings suggest that expression of an alternatively spliced, truncated ERα isoform in human endothelial cells confers a unique ability to mediate acute but not transcriptional responses to estrogen.
Sirolimus-Eluting Stent for the Treatment of In-Stent Restenosis
Authors: Sousa J. Eduardo , Costa Marco A. , Abizaid Alexandre , Sousa Amanda G.M.R. , Feres Fausto , Mattos Luiz A. , Centemero Marinella , Maldonado Galo , Abizaid Andrea S. , Pinto Ibraim , Falotico Robert , Jaeger Judith , Popma Jeffrey J. , Serruys Patrick W.
Published: January 2003

Background—

We have previously reported the safety and effectiveness of sirolimus-eluting stents for the treatment of de novo coronary lesions. The present investigation explored the potential of this technology to treat in-stent restenosis.

Methods and Results—

Twenty-five patients with in-stent restenosis were successfully treated with the implantation of 1 or 2 sirolimus-eluting Bx VELOCITY stents in São Paulo, Brazil. Nine patients received 2 stents (1.4 stents per lesion). Angiographic and volumetric intravascular ultrasound (IVUS) images were obtained after the procedure and at 4 and 12 months. All vessels were patent at the time of 12-month angiography. Angiographic late loss averaged 0.07±0.2 mm in-stent and −0.05±0.3 mm in-lesion at 4 months, and 0.36±0.46 mm in-stent and 0.16±0.42 mm in-lesion after 12 months. No patient had in-stent or stent margin restenosis at 4 months, and only one patient developed in-stent restenosis at 1-year follow-up. Intimal hyperplasia by 3-dimensional IVUS was 0.92±1.9 mm
3
at 4 months and 2.55±4.9 mm
3
after 1 year. Percent volume obstruction was 0.81±1.7% and 1.76±3.4% at the 4- and 12-month follow-up, respectively. There was no evidence of stent malapposition either acutely or in the follow-up IVUS images, and there were no deaths, stent thromboses, or repeat revascularizations.

Conclusion—

This study demonstrates the safety and the potential utility of sirolimus-eluting Bx VELOCITY stents for the treatment of in-stent restenosis.
Pulmonary Vein Ostium Geometry
Authors: Wittkampf Fred H.M. , Vonken Evert-Jan , Derksen Richard , Loh Peter , Velthuis Birgitta , Wever Eric F.D. , Boersma Lucas V.A. , Rensing Benno J. , Cramer Maarten-Jan
Published: January 2003

Background—

During a catheter ablation procedure for selective electrical isolation of pulmonary vein (PV) ostia, the size of these ostia is usually estimated using fluoroscopic angiography. This measurement may be misleading, however, because only the projected supero/inferior ostium diameters can be measured. In this study, we analyzed 3-dimensional magnetic resonance angiographic (MRA) images to measure the minimal and maximal cross-sectional diameter of PV ostia in relation to the diameter that would have been projected on fluoroscopic angiograms during a catheter ablation procedure.

Methods and Results—

In 42 patients with idiopathic atrial fibrillation who were scheduled for selective electrical isolation of PV ostia, the minimal and maximal diameters of these ostia were measured from 3-dimensional MRA images. Thereafter, these images were oriented in a 45° right or left anterior oblique direction and the projected diameter of the PV ostia were measured again. The average ratio between maximal and minimal diameter was 1.5±0.4 for the left and 1.2±0.1 for the right pulmonary vein ostia. Because of the orientation and oval shape of especially the left pulmonary vein ostia, their minimal diameters were significantly smaller than the projected diameters.

Conclusion—

Pulmonary vein ostia, especially those at the left, are oval with the short axis oriented approximately in the antero/posterior direction. Consequently, PV ostia may sometimes be very narrow despite a rather normal appearance on angiographic images obtained during a catheter ablation procedure.
Adenoviral Gene Transfer of Fortilin Attenuates Neointima Formation Through Suppression of Vascular Smooth Muscle Cell Proliferation and Migration
Authors: Tulis David A. , Mnjoyan Zakar H. , Schiesser Rachel L. , Shelat Harnath S. , Evans Alida J. , Zoldhelyi Pierre , Fujise Ken
Published: January 2003

Background—

Fortilin, a recently characterized nuclear antiapoptotic factor structurally distinct from inhibitor of apoptosis proteins (IAPs) and Bcl-2 family member proteins, has been suggested to be involved in cell survival and regulation of apoptosis within the cardiovascular system. In this continued investigation, we characterized the influence of adenovirus-mediated fortilin (Ad-fortilin) gene delivery on vascular remodeling after experimental angioplasty.

Methods and Results—

Vessel wall expression of Ad-fortilin or adenoviral luciferase (Ad-luc) was demonstrated 72 hours and 14 days after rat carotid artery (CA) balloon angioplasty. Morphometric analyses 14 days after injury revealed significantly diminished neointima development in the Ad-fortilin–treated CAs compared with Ad-luc or PBS controls, with no changes in medial wall morphometry observed between the 3 groups. The Ad-fortilin–treated CAs demonstrated a 50% reduction in medial wall proliferating cell nuclear antigen (PCNA) labeling after 72 hours, with significantly reduced neointimal and medial wall PCNA labeling and cell counts after 14 days. Terminal dUTP nick-end labeling results and morphological changes characteristic of programmed cell death suggest a trend toward reduced apoptosis in the fortilin-transfected balloon-injured vessels compared with Ad-luc injured controls. Temporal analysis of human aorta smooth muscle cell (SMC) proliferation demonstrated a marked time-dependent inhibition in Ad-fortilin treated SMCs without the influence of elevated apoptosis. Thymidine incorporation was significantly inhibited in the Ad-fortilin–treated cells compared with Ad-luc controls. Ad-fortilin transfected SMCs also demonstrated significantly decreased migration compared with Ad-luc controls.

Conclusions—

These cumulative results suggest that the novel antiapoptotic protein fortilin may play important redundant pathophysiological roles in modulating the vascular response to experimental angioplasty through suppression of SMC proliferation and migration concomitant with reduction of vessel wall apoptosis.
Coming into Sight: Seeing Robert Delaunay's Structure of Vision
Authors: Hughes Gordon
Published: January 2003

Take my hand, traveler, and let us go up the tower. Look below, and look around. Look right to the end of the horizon, look From north to south. Everywhere your eye happens to fall It attaches itself with fire, like the eye of a snake. —Alfred de Vigny, “Paris” (1831)
EMPATH: A Neural Network that Categorizes Facial Expressions
Authors: Dailey Matthew N. , Cottrell Garrison W. , Padgett Curtis , Adolphs Ralph
Published: January 2003

There are two competing theories of facial expression recognition. Some researchers have suggested that it is an example of “categorical perception.” In this view, expression categories are considered to be discrete entities with sharp boundaries, and discrimination of nearby pairs of expressive faces is enhanced near those boundaries. Other researchers, however, suggest that facial expression perception is more graded and that facial expressions are best thought of as points in a continuous, low-dimensional space, where, for instance, “surprise” expressions lie between “happiness” and “fear” expressions due to their perceptual similarity. In this article, we show that a simple yet biologically plausible neural network model, trained to classify facial expressions into six basic emotions, predicts data used to support both of these theories. Without any parameter tuning, the model matches a variety of psychological data on categorization, similarity, reaction times, discrimination, and recognition difficulty, both qualitatively and quantitatively. We thus explain many of the seemingly complex psychological phenomena related to facial expression perception as natural consequences of the tasks' implementations in the brain.
Blindsight Modulation of Motion Perception
Authors: Intriligator James M. , Xie Ruiman , Barton Jason J. S.
Published: January 2003

Monkey data suggest that of all perceptual abilities, motion perception is the most likely to survive striate damage. The results of studies on motion blindsight in humans, though, are mixed. We used an indirect strategy to examine how responses to visible stimuli were modulated by blind-field stimuli. In a 26-year-old man with focal striate lesions, discrimination of visible optic flow was enhanced about 7% by blind-field flow, even though discrimination of optic flow in the blind field alone (the direct strategy) was at chance. Pursuit of an imagined target using peripheral cues showed reduced variance but not increased gain with blind-field cues. Preceding blind-field prompts shortened reaction times to visible targets by about 10 msec, but there was no attentional crowding of visible stimuli by blind-field distractors. A similar efficacy of indirect blind-field optic flow modulation was found in a second patient with residual vision after focal striate damage, but not in a third with more extensive medial occipito-temporal damage. We conclude that indirect modulatory strategies are more effective than direct forced-choice methods at revealing residual motion perception after focal striate lesions.
Localization of Executive Functions in Dual-Task Performance with fMRI
Authors: Szameitat André J. , Schubert Torsten , Müller Karsten , von Cramon D. Yves
Published: January 2003

We report a study that investigated the neuroanatomical correlates of executive functions in dual-task performance with functional magnetic resonance imaging. Participants performed an auditory and a visual three-choice reaction task either separately as single tasks or concurrently as dual tasks. In the dual-task condition, two stimuli were presented in rapid succession to ensure interference between the component tasks (psychological refractory period). The behavioral data showed considerable performance decrements in the dual-task compared to the single-task condition. Dual-task-related activation was detected with two different neuroimaging methods. First, we determined dual-task-related activation according to the method of cognitive subtraction. For that purpose, activation in the dual-task was compared directly with activation in the single-task conditions. This analysis revealed that cortical areas along the inferior frontal sulcus (IFS), the middle frontal gyrus (MFG), and the intraparietal sulcus (IPS) are involved in dual-task performance. The results of the subtraction method were validated with the method of parametric manipulation. For this purpose, a second dual-task condition was introduced, where the difficulty of the dual-task coordination was increased compared with the first dual-task condition. As expected, behavioral dual-task performance decreased with increased dual-task difficulty. Furthermore, the increased dual-task difficulty led to an increase of activation in those cortical regions that proved to be dual-task related with the subtraction method, that is, the IFS, the MFG, and the IPS. These results support the conclusion that dorsolateral prefrontal and superior parietal cortices are involved in the coordination of concurrent and interfering task processing.
Rethinking Feelings: An fMRI Study of the Cognitive Regulation of Emotion
Authors: Ochsner Kevin N. , Bunge Silvia A. , Gross James J. , Gabrieli John D. E.
Published: January 2003

The ability to cognitively regulate emotional responses to aversive events is important for mental and physical health. Little is known, however, about neural bases of the cognitive control of emotion. The present study employed functional magnetic resonance imaging to examine the neural systems used to reappraise highly negative scenes in unemotional terms. Reappraisal of highly negative scenes reduced subjective experience of negative affect. Neural correlates of reappraisal were increased activation of the lateral and medial prefrontal regions and decreased activation of the amygdala and medial orbito-frontal cortex. These findings support the hypothesis that prefrontal cortex is involved in constructing reappraisal strategies that can modulate activity in multiple emotion-processing systems.
Contribution of the Primate Superior Colliculus to Inhibition of Return
Authors: Dorris Michael C. , Klein Raymond M. , Everling Stefan , Munoz Douglas P.
Published: January 2003

The phenomenon of inhibition of return (IOR) has generated considerable interest in cognitive neuroscience because of its putative functional role in visual search, that of placing inhibitory tags on objects that have been recently inspected so as to direct further search to novel items. Many behavioral parameters of this phenomenon have been clearly delineated, and based on indirect but converging evidence, the widely held consensus is that the midbrain superior colliculus (SC) is involved in the generation of IOR. We had previously trained monkeys on a saccadic IOR task and showed that they displayed IOR in a manner similar to that observed in humans. Here we recorded the activity of single neurons in the superficial and intermediate layers of the SC while the monkeys performed this IOR task. We found that when the target was presented at a previously cued location, the stimulus-related response was attenuated and the magnitude of this response was correlated with subsequent saccadic reaction times. Surprisingly, this observed attenuation of activity during IOR was not caused by active inhibition of these neurons because (a) they were, in fact, more active following the presentation of the cue in their response field, and (b) when we repeated the same experiment while using the saccadic response time induced by electrical micro-stimulation of the SC to judge the level of excitability of the SC circuitry during the IOR task, we found faster saccades were elicited from the cued location. Our findings demonstrate that the primate SC participates in the expression of IOR; however, the SC is not the site of the inhibition. Instead, the reduced activity in the SC reflects a signal reduction that has taken place upstream.
Impaired Recognition of Social Emotions following Amygdala Damage
Authors: Adolphs Ralph , Baron-Cohen Simon , Tranel Daniel
Published: January 2003

Lesion, functional imaging, and single-unit studies in human and nonhuman animals have demonstrated a role for the amygdala in processing stimuli with emotional and social significance. We investigated the recognition of a wide variety of facial expressions, including basic emotions (e.g., happiness, anger) and social emotions (e.g., guilt, admiration, flirtatiousness). Prior findings with a standardized set of stimuli indicated that recognition of social emotions can be signaled by the eye region of the face and is disproportionately impaired in autism (Baron-Cohen, Wheelwright, & Jolliffe, 1997). To test the hypothesis that the recognition of social emotions depends on the amygdala, we administered the same stimuli to 30 subjects with unilateral amygdala damage (16 left, 14 right), 2 with bilateral amygdala damage, 47 brain-damaged controls, and 19 normal controls. Compared with controls, subjects with unilateral or bilateral amygdala damage were impaired when recognizing social emotions; moreover, they were more impaired in recognition of social emotions than in recognition of basic emotions, and, like previously described patients with autism, they were impaired also when asked to recognize social emotions from the eye region of the face alone. The findings suggest that the human amygdala is relatively specialized to process stimuli with complex social significance. The results also provide further support for the idea that some of the impairments in social cognition seen in patients with autism may result from dysfunction of the amygdala.
On Different Facets of Regularization Theory
Authors: Chen Zhe , Haykin Simon
Published: January 2003

This review provides a comprehensive understanding of regularization theory from different perspectives, emphasizing smoothness and simplicity principles. Using the tools of operator theory and Fourier analysis, it is shown that the solution of the classical Tikhonov regularization problem can be derived from the regularized functional defined by a linear differential (integral) operator in the spatial (Fourier) domain. State-ofthe-art research relevant to the regularization theory is reviewed, covering Occam's razor, minimum length description, Bayesian theory, pruning algorithms, informational (entropy) theory, statistical learning theory, and equivalent regularization. The universal principle of regularization in terms of Kolmogorov complexity is discussed. Finally, some prospective studies on regularization theory and beyond are suggested.
Self-Regulation Mechanism of Temporally Asymmetric Hebbian Plasticity
Authors: Matsumoto Narihisa , Okada Masato
Published: January 2003

Recent biological experimental findings have shown that synaptic plasticity depends on the relative timing of the pre- and postsynaptic spikes. This determines whether long-term potentiation (LTP) or long-term depression (LTD) is induced. This synaptic plasticity has been called temporally asymmetric Hebbian plasticity (TAH). Many authors have numerically demonstrated that neural networks are capable of storing spatiotemporal patterns. However, the mathematical mechanism of the storage of spatiotemporal patterns is still unknown, and the effect of LTD is particularly unknown. In this article, we employ a simple neural network model and show that interference between LTP and LTD disappears in a sparse coding scheme. On the other hand, the covariance learning rule is known to be indispensable for the storage of sparse patterns. We also show that TAH has the same qualitative effect as the covariance rule when spatiotemporal patterns are embedded in the network.
Adaptive Spatiotemporal Receptive Field Estimation in the Visual Pathway
Authors: Stanley Garrett B.
Published: January 2003

The encoding properties of the visual pathway are under constant control from mechanisms of adaptation and systems-level plasticity. In all but the most artificial experimental conditions, these mechanisms serve to continuously modulate the spatial and temporal receptive field (RF) dynamics. Conventional reverse-correlation techniques designed to capture spatiotemporal RF properties assume invariant stimulus-response relationships over experimental trials and are thus limited in their applicability to more natural experimental conditions. Presented here is an approach to tracking time-varying encoding dynamics in the early visual pathway based on adaptive estimation of the spatiotemporal RF in the time domain. Simulations and experimental data from the lateral geniculate nucleus reveal that subtle features of encoding properties can be captured by the adaptive approach that would otherwise be undetected. Capturing the role of dynamically varying encoding mechanisms is vital to our understanding of vision on the natural setting, where there is absence of a true steady state.
Descartes' Rule of Signs for Radial Basis Function Neural Networks
Authors: Schmitt Michael
Published: January 2003

We establish versions of Descartes' rule of signs for radial basis function (RBF) neural networks. The RBF rules of signs provide tight bounds for the number of zeros of univariate networks with certain parameter restrictions. Moreover, they can be used to infer that the Vapnik-Chervonenkis (VC) dimension and pseudodimension of these networks are no more than linear. This contrasts with previous work showing that RBF neural networks with two or more input nodes have superlinear VC dimension. The rules also give rise to lower bounds for network sizes, thus demonstrating the relevance of network parameters for the complexity of computing with RBF neural networks.
Approximation Bounds for Some Sparse Kernel Regression Algorithms
Authors: Zhang Tong
Published: January 2003

Gaussian processes have been widely applied to regression problems with good performance. However, they can be computationally expensive. In order to reduce the computational cost, there have been recent studies on using sparse approximations in gaussian processes. In this article, we investigate properties of certain sparse regression algorithms that approximately solve a gaussian process. We obtain approximation bounds and compare our results with related methods.
Between History and Event: Rehearsing Nuclear War Survival
Authors: Davis Tracy C.
Published: January 2003

Performance historian Davis opens a window onto the civil defense movement that was a mainstay of Western governments from 1949 until the collapse of the Eastern Bloc from 1989 to 1991. Civil defense activities included playing out many “as if” scenarios wherein a “time out of time” reality was created, something that NATO members referred to as the “scope of play” (portée du jeu) and the “play of decisions” (jou des décisions). These activities, Davis argues, are inherently performative. But are they history?
Steve Paxton's Goldberg Variations and the Angel of History
Authors: Burt Ramsay
Published: January 2003

Using Paxton's Goldberg Variations—an improvised dance performed between 1986 and 1992 to pianist Glenn Gould's celebrated recordings of Bach's music—Burt investigates the problems of live performances long since passed into memory and videotape. Burt's intention is to help imagine another way of writing about performance that acknowledges the value of all those qualities within dance performances that cannot be fixed and are gradually destroyed through rehearsal; yet, paradoxically, without these very qualities, performance could not exist.
Apocalipse 1, 11 in São Paulo: Aesthetic Vertigo or Exploitation?
Authors: Stanton William
Published: January 2003

Performed in an abandoned prison, Apocalipse I, II re-enacts a 1992 massacre at São Paulo's Carandiru prison where 111 prisoners were shot by the military police. But the inclusion of a live sex show and gratuitous violence raises questions. Apocalipse I, II sought to use theatrical coups to politicize its audience. But for Stanton it failed to get beyond its own gleefully explicit transgressions and develop a coherent critical narrative of the state of Brazil that could empower its audience.
The Golden Arches and the Ivory Tower: Creating an Acto on the Corporate University
Authors: Mason Susan Vaneta
Published: January 2003

Between 16 and 25 October 2001, the faculty union of the California State Universities held teach-ins on all the CSU campuses. To support this effort, Mason and her colleagues created Education Inc., or How I Learned to Stop Thinking and Love Measurement-Driven Instruction. Research for the play taught them that all levels of U.S. public education are struggling with the destructive effects corporate thinking is having on education.
My Art in Life: Interviewing Spalding Gray
Authors: Schechner Richard
Published: January 2003

The monologist narrates the story of his life—or one version of it—in an encounter with his longtime friend and former director, Richard Schechner.
Breathing Common Air: The SITI Company Creates Cabin Pressure
Authors: Herrington Joan
Published: January 2003

Before the production, there are the rehearsals. How do Anne Bogart and her SITI company devise and rehearse their performances? Herrington followed the process from the research phase through workshops and rehearsals to opening night—which hardly concluded the work.
Three-Dimensional Motion and Structure Estimation Using Inertial Sensors and Computer Vision for Augmented Reality
Authors: Chai Lin , Hoff William A. , Vincent Tyrone
Published: January 2003

A new method for registration in augmented reality (AR) was developed that simultaneously tracks the position, orientation, and motion of the user's head, as well as estimating the three-dimensional (3D) structure of the scene. The method fuses data from head-mounted cameras and head-mounted inertial sensors. Two extended Kalman filters (EKFs) are used: one estimates the motion of the user's head and the other estimates the 3D locations of points in the scene. A recursive loop is used between the two EKFs. The algorithm was tested using a combination of synthetic and real data, and in general was found to perform well. A further test showed that a system using two cameras performed much better than a system using a single camera, although improving the accuracy of the inertial sensors can partially compensate for the loss of one camera. The method is suitable for use in completely unstructured and unprepared environments. Unlike previous work in this area, this method requires no a priori knowledge about the scene, and can work in environments in which the objects of interest are close to the user.
Assistance for Telepresence by Stereovision-Based Augmented Reality and Interactivity in 3D Space
Authors: Fuchs Philippe , Nashashibi Fawzi , Maman Didier
Published: January 2003

In this paper, we describe some use of mixed reality as a new assistance for performing teleoperation tasks in remote scenes. We will start by a brief classification of augmented reality. This paper then describes the principle of our mixed reality system in teleoperation. It tackles the problem of scene registration using a man–machine cooperative and multisensory vision system. The system provides the operator with powerful sensorial feedback as well as appropriate tools to build (and update automatically) the geometric model of the perceived scene. We describe a new interactive approach combining image analysis and mixed reality techniques for assisted 3D geometric and semantic modeling. At the end of this paper, we describe applications in nuclear plants with results in 3D positioning.