bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of spatial scale in understanding responses of medium-sized carnivores to forest fragmentation
Authors: Oehler James D. , Litvaitis John A.
Published: January 2008

Increased predation has been suggested as a proximate factor causing the decline of vertebrate diversity in many human-altered landscapes. Previous studies on this topic have provided conflicting results, perhaps as a consequence of the limited spatial scale used in these investigations. We incorporated a multiscaled approach (using site, plot (1.44 km2), and landscape (54 km2)) to investigate the distribution of activity of medium-sized carnivores relative to habitat edges and the numeric responses of these predators to habitat diversity. Among the taxa surveyed, raccoons (Procyon lotor) did not show an affinity for habitat edges at any spatial scale. However, raccoons were more abundant in landscapes characterized by a diversity of cover types. Free-ranging domestic dogs (Canis familiaris) and cats (Felis domesticus) did not respond to the proximity of habitat edges in summer but showed a strong affinity for edge habitats (especially those associated with human dwellings) during winter. Wild canids (Vulpes vulpes and Canis latrans) also selected sites in close proximity to edges in winter and were more abundant in diverse landscapes. Although human-dominated habitats (agricultural areas, grass–brushland, and developed sites) represented only 7–27% of the three landscapes studied, populations of generalist predators (raccoons and wild canids) increased as landscapes became more diverse. As a result, even moderate levels of habitat fragmentation may elevate predation rates and subsequently alter the composition of prey communities.
Patterns of species diversity in the gastrointestinal helminths of a coral reef fish, Epinephelus merra (Serranidae), from French Polynesia and the South Pacific Ocean
Authors: Rigby Mark C. , Holmes John C. , Cribb Thomas H. , Morand Serge
Published: January 2008

Large-scale patterns of species diversity in the gastrointestinal helminth faunas of the coral reef fish Epinephelus merra (Serranidae) were investigated in French Polynesia and the South Pacific Ocean. The richer barrier reef community in French Polynesia supported richer parasite communities in E. merra than that on the fringing reef. While parasite communities among fish from the same archipelago were similar, differences in potential host species and the distance between archipelagos may have contributed to a qualitative difference in parasite communities between archipelagos. Digenean community diversity in coral reef fishes was greater in the western South Pacific, following similar patterns in free-living species. However, overall species diversity of camallanid nematodes of coral reef fishes does not appear to have been similarly affected.
Sex differences in site fidelity and migration of humpback whales (Megaptera novaeangliae) to the Hawaiian Islands
Authors: Craig Alison S. , Herman Louis M.
Published: January 2008

Humpback whales (Megaptera novaeangliae) perform extensive seasonal migrations between high-latitude summer feeding grounds and low-latitude winter reproductive grounds. To investigate gender-related site fidelity to the Hawaiian Islands, an important wintering area for North Pacific humpback whales, photographically based resight histories of 224 females and 416 males observed in Hawai'i from 1976 through 1991 were compiled. Results indicated that the mean number of years in which they were seen was higher for males than for females, that the probability of an individual being resighted across years was higher for males than for females, and that more males than females were seen in consecutive years. Potential sources of bias favoring the photographic capture of males were considered, but none were judged to be significant contributors to the results obtained. It was proposed instead that not all females undertake or complete the migration to the winter grounds each year. Because of the high energy costs of migration and reproduction, some females may overwinter in high latitudes, while others may become pregnant en route to the area traditionally associated with breeding and return to the feeding grounds before arriving at the terminal winter destination.
Response of antler growth to changing rank of fallow deer buck during the velvet period
Authors: Bartoš L. , Losos S.
Published: January 2008

We examined how strongly any change in rank of a male fallow deer (Dama dama) during antler growth affected the pattern of development of his antlers. Rank was determined from victories in fights with other bucks and summarized as "dominance success," recorded at specific, well-defined stages of antler growth. We tested whether the size attained by various parts of the antler is more closely related to dominance success of the buck during their development than to average success over the whole velvet period. To test this hypothesis, 10 fallow deer bucks aged 4 years were observed throughout the velvet period. After the velvet was shed, the antlers were measured. Most of the measured characteristics of the antlers reflected dominance success during the time that they were developing rather than the average rank over the whole period of antler growth. Thus, changes in behaviour related to rank modified antler growth. Bucks gaining higher rank through fighting more bucks exhibited enhanced growth of that part of the antler that was just developing. This changed if the buck lost his position.
STATEFINDER PARAMETERS FOR TACHYON DARK ENERGY MODEL
Authors: SHAO YING , GUI YUANXING
Published: January 2008

In this paper we study the statefinder parameters for the tachyon dark energy model. There are two kinds of stable attractor solutions in this model. The statefinder diagrams characterize the properties of the tachyon dark energy model. Our results show that the evolving trajectories of the attractor solutions lie in the total region and pass through the LCDM fixed point, which is different from other dark energy model.
ENTROPY OF CONTRACTING UNIVERSE IN CYCLIC COSMOLOGY
Authors: BAUM LAURIS , FRAMPTON PAUL H.
Published: January 2008

Following up a recent proposal1 for a cyclic model based on phantom dark energy, we examine the content of the contracting universe (cu) and its entropy S cu . We find that beyond dark energy, the universe contains on average zero or an unlikely single photon which if present immediately after turnaround would have infinitesimal energy that blue shifts eventually to produce e+e- pairs. These statements are independent of the equation of state ω = p/ρ of dark energy provided ω < -1. Thus S cu = 0 and if observations confirm ω < -1, the entropy problem is solved. We discuss the absence of a theoretical lower bound on ϕ = |ω+1|, then describe an anthropic fine tuning argument that renders unlikely extremely small ϕ. The present bound ϕ ≲ 0.1 already implies a time until turnaround of (tT - t0) ≳ 100 Gy.
BARYONIC ACOUSTIC OSCILLATIONS VIA THE RENORMALIZATION GROUP
Authors: MATARRESE SABINO , PIETRONI MASSIMO
Published: January 2008

Renormalization Group techniques, successfully employed in quantum field theory and statistical physics, are applied to study the dynamics of structure formation in the Universe. A semi-analytic approach to the computation of the nonlinear power-spectrum of dark matter density fluctuations is proposed. The method can be applied down to zero redshift and to length scales where perturbation theory fails. Our predictions accurately fit the results of numerical simulations in reproducing the "acoustic oscillations" features of the power spectrum, which will be accurately measured in future galaxy surveys and will provide a probe to distinguish among different dark energy models.
COHERENT TRANSPORT OF LIGHT IN COLD ATOMS
Authors: LABEYRIE GUILLAUME
Published: January 2008

We present an overview of the investigations on the transport of near-resonant light in laser-cooled atomic vapors, a field that emerged during the past decade. We first discuss time-resolved measurements yielding some informations on the nature of this transport, which is quasi-diffusive for low temperatures and limited optical thicknesses. We then focus on the coherence of the transport, which is probed using the coherent backscattering interference. We identify and analyze in detail several mechanisms limiting the coherence length in such media.
SELECTIVE NAIVE BAYES FOR REGRESSION BASED ON MIXTURES OF TRUNCATED EXPONENTIALS
Authors: MORALES MARÍA , RODRÍGUEZ CARMELO , SALMERÓN ANTONIO
Published: January 2008

Naive Bayes models have been successfully used in classification problems where the class variable is discrete. These models have also been applied to regression or prediction problems, i.e. classification problems where the class variable is continuous, but usually under the assumption that the joint distribution of the feature variables and the class is multivariate Gaussian. In this paper we are interested in regression problems where some of the feature variables are discrete while the others are continuous. We propose a Naive Bayes predictor based on the approximation of the joint distribution by a Mixture of Truncated Exponentials (MTE). We have followed a filter-wrapper procedure for selecting the variables to be used in the construction of the model. This scheme is based on the mutual information between each of the candidate variables and the class. Since the mutual information can not be computed exactly for the MTE distribution, we introduce an unbiased estimator of it, based on Monte Carlo methods. We test the performance of the proposed model in artificial and real-world datasets.
Hepatic portal venous delivery of a nitric oxide synthase inhibitor enhances net hepatic glucose uptake
Authors: Moore Mary Courtney , DiCostanzo Catherine A. , Smith Marta S. , Farmer Ben , Rodewald Tiffany D. , Neal Doss W. , Williams Phillip E. , Cherrington Alan D.
Published: January 2008

Hepatic portal venous infusion of nitric oxide synthase (NOS) inhibitors causes muscle insulin resistance, but the effects on hepatic glucose disposition are unknown. Conscious dogs underwent a hyperinsulinemic (4-fold basal) hyperglycemic (hepatic glucose load 2-fold basal) clamp, with assessment of liver metabolism by arteriovenous difference methods. After 90 min (P1), dogs were divided into two groups: control (receiving intraportal saline infusion; n = 8) and LN [receiving NG-nitro-l-arginine methyl ester (l-NAME), a nonspecific NOS inhibitor; n = 11] intraportally at 0.3 mg·kg−1·min−1 for 90 min (P2). During the final 60 min of study (P3), l-NAME was discontinued, and five LN dogs received the NO donor SIN-1 intraportally at 6 μg·kg−1·min−1 while six received saline (LN/SIN-1 and LN/SAL, respectively). Net hepatic fractional glucose extraction (NHFE) in control dogs was 0.034 ± 0.016, 0.039 ± 0.015, and 0.056 ± 0.019 during P1, P2, and P3, respectively. NHFE in LN was 0.045 ± 0.009 and 0.111 ± 0.007 during P1 and P2, respectively ( P < 0.05 vs. control during P2), and 0.087 ± 0.009 and 0.122 ± 0.016 ( P < 0.05) during P3 in LN/SIN-1 and LN/SAL, respectively. During P2, arterial glucose was 204 ± 5 vs. 138 ± 11 mg/dl ( P < 0.05) in LN vs. control to compensate for l-NAME's effect on blood flow. Therefore, another group (LNlow; n = 4) was studied in the same manner as LN/SAL, except that arterial glucose was clamped at the same concentrations as in control. NHFE in LNlow was 0.052 ± 0.008, 0.093 ± 0.023, and 0.122 ± 0.021 during P1, P2, and P3, respectively ( P < 0.05 vs. control during P2 and P3), with no significant difference in glucose infusion rates. Thus, NOS inhibition enhanced NHFE, an effect partially reversed by SIN-1.
Rabbits fed cholesterol-enriched diets exhibit pathological features of inclusion body myositis
Authors: Chen Xuesong , Ghribi Othman , Geiger Jonathan D.
Published: January 2008

Sporadic inclusion body myositis (IBM) is the most common age-related muscle disease in humans; however, its etiology is unknown, there are few animal models for this disease, and effective treatments have not been identified. Similarities between pathological findings in Alzheimer's disease brain and IBM skeletal muscle include increased levels of amyloid precursor protein (APP) and amyloid β-protein (Aβ). Moreover, there have been suggestions that elevated levels of free cholesterol might participate in the pathogenesis of Alzheimer's disease and IBM due, in part, to its role in Aβ generation. Here, we tested the hypothesis that rabbits fed cholesterol-enriched diets might faithfully exhibit human-like IBM pathological features. In skeletal muscle of one-third of the female rabbits fed cholesterol-enriched diet but not control diet, we found features of IBM, including vacuolated muscle fibers, increased numbers of mononuclear inflammatory cells, increased intramuscular deposition of Aβ, hyperphosphorylated tau, and increased numbers of muscle fibers immunopositive for ubiquitin. The cholesterol-enriched diet increased mRNA and protein levels of APP, increased the protein levels of βAPP cleaving enzyme, and shifted APP processing in favor of Aβ production. Our study has demonstrated that increased ingestion of high levels of dietary cholesterol can result in pathological features that resemble IBM closely and thus may serve as an important new model with which to study this debilitating disorder.
Interhemispheric EEG asymmetries during unilateral bright-light exposure and subsequent sleep in humans
Authors: Cajochen Christian , Biase Rosalba Di , Imai Makoto
Published: January 2008

We tested whether evening exposure to unilateral photic stimulation has repercussions on interhemispheric EEG asymmetries during wakefulness and later sleep. Because light exerts an alerting response in humans, which correlates with a decrease in waking EEG theta/alpha-activity and a reduction in sleep EEG delta activity, we hypothesized that EEG activity in these frequency bands show interhemispheric asymmetries after unilateral bright light (1,500 lux) exposure. A 2-h hemi-field light exposure acutely suppressed occipital EEG alpha activity in the ipsilateral hemisphere activated by light. Subjects felt more alert during bright light than dim light, an effect that was significantly more pronounced during activation of the right than the left visual cortex. During subsequent sleep, occipital EEG activity in the delta and theta range was significantly reduced after activation of the right visual cortex but not after stimulation of the left visual cortex. Furthermore, hemivisual field light exposure was able to shift the left predominance in occipital spindle EEG activity toward the stimulated hemisphere. Time course analysis revealed that this spindle shift remained significant during the first two sleep cycles. Our results reflect rather a hemispheric asymmetry in the alerting action of light than a use-dependent recovery function of sleep in response to the visual stimulation during prior waking. However, the observed shift in the spindle hemispheric dominance in the occipital cortex may still represent subtle local use-dependent recovery functions during sleep in a frequency range different from the delta range.
Pioneers of cortical plasticity: six classic papers by Wiesel and Hubel
Authors: Constantine-Paton Martha
Published: January 2008

This essay looks at six APS classic papers published by D. H. Hubel and T. N. Wiesel that first identified a developmental critical period for environment influenced receptive field plasticity in the visual pathway. These classic papers are freely available online. These are listed here, in chronological order.

Wiesel TN, Hubel DH.

Effects of visual deprivation on morphology and physiology of cells in the cat's lateral geniculate body. J Neurophysiol 26: 978–993, 1963 ( http://jn.physiology.org/cgi/reprint/26/6/978 ).

Hubel DH, Wiesel TN.

Receptive fields of cells in striate cortex of very young, visually inexperienced kittens. J Neurophysiol 26: 994–1002, 1963 ( http://jn.physiology.org/cgi/reprint/26/6/994 ).

Wiesel TN, Hubel DH.

Single-cell responses in striate cortex of kittens deprived of vision in one eye. J Neurophysiol 26: 1003–1017, 1963 ( http://jn.physiology.org/cgi/reprint/26/6/1003 ).

Wiesel TN, Hubel DH.

Comparison of the effects of unilateral and bilateral eye closure on cortical unit responses in kittens. J Neurophysiol 28: 1029–1040, 1965 ( http://jn.physiology.org/cgi/reprint/28/6/1029 ).

Hubel DH, Wiesel TN.

Binocular interaction in striate cortex of kittens reared with artificial squint. J Neurophysiol 28: 1041–1059, 1965 ( http://jn.physiology.org/cgi/reprint/28/6/1041 ).

Wiesel TN, Hubel DH.

Extent of recovery from the effects of visual deprivation in kittens. J Neurophysiol 28: 1060–1072, 1965 ( http://jn.physiology.org/cgi/reprint/28/6/1060 ).
Oral Buflomedil in the Prevention of Cardiovascular Events in Patients With Peripheral Arterial Obstructive Disease
Authors:   Limbs International Medicinal Buflomedil (LIMB) Study Group
Published: January 2008

Background—

Cardiovascular-related morbidity and mortality in patients with peripheral arterial obstructive disease remain high. We performed an international, multicenter, randomized, double-blind, placebo-controlled trial to investigate whether long-term administration of oral buflomedil could reduce the rate of cardiovascular events in patients with intermittent claudication.

Methods and Results—

Patients >40 years of age with documented peripheral arterial obstructive disease, intermittent claudication, and an ankle-brachial index between 0.30 and 0.80 were eligible for inclusion and were randomized to receive orally either buflomedil or placebo for 2 to 4 years. Aspirin was recommended for all patients (unless they were receiving other antithrombotic treatments at inclusion). The primary efficacy outcome was critical cardiovascular events, defined as the composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, symptomatic deterioration of peripheral arterial obstructive disease, or leg amputation. A total of 2078 patients were recruited. Mean treatment duration was 33 months. The rate of critical cardiovascular events was significantly lower in buflomedil-randomized patients than in placebo-randomized patients (9.1% versus 12.4%; hazard ratio, 0.742; 95% confidence interval, 0.603 to 0.915;
P
=0.0163). Ankle-brachial index increased by 9.2% in buflomedil-randomized patients and decreased by 3.6% in placebo-randomized patients (
P
<0.001). Tolerance of buflomedil and placebo was comparable.

Conclusions—

Compared with placebo, buflomedil administered for 3 years reduced the occurrence of symptomatic cardiovascular events by 26%. The main contributor to the difference in the composite outcome was the reduction in symptomatic deterioration of peripheral arterial disease. The use of buflomedil should be considered in addition to an antiplatelet agent in patients with peripheral arterial obstructive disease and intermittent claudication.
Endothelial Lipase Is Increased In Vivo by Inflammation in Humans
Authors: Badellino Karen O. , Wolfe Megan L. , Reilly Muredach P. , Rader Daniel J.
Published: January 2008

Background—

Endothelial lipase (EL) is a plasma lipase that we previously reported to be significantly correlated with all features of the metabolic syndrome in humans, including directly with measures of adiposity and inversely with high-density lipoprotein cholesterol levels. We hypothesized that inflammation associated with obesity results in upregulation of EL. We determined the relationship between inflammatory markers and EL levels in a cohort of healthy persons recruited on the basis of family history of coronary disease. Furthermore, we directly tested the hypothesis that plasma EL concentrations would increase with induction of an inflammatory state by low-dose endotoxin in humans.

Methods and Results—

High-sensitivity C-reactive protein, interleukin 6, soluble tumor necrosis factor receptor II, soluble intercellular adhesion molecule 1, leptin, and adiponectin were measured in plasma of 858 subjects. Significant direct correlations (
P
<0.001 for all) were found between EL concentrations and high-sensitivity C-reactive protein (
r
=0.28), interleukin-6 (
r
=0.22), soluble tumor necrosis factor receptor II (
r
=0.22), soluble intercellular adhesion molecule 1 (
r
=0.24), and leptin (
r
=0.20). An inverse correlation was present with adiponectin (
r
=−0.15,
P
<0.001). Adiponectin inhibited the tumor necrosis factor-α–stimulated EL secretion from cultured human coronary endothelial cells in a dose-dependent manner. Experimental low-dose endotoxemia in 20 subjects resulted in a 2.5-fold increase in EL concentrations 12 to 16 hours after injection, which correlated temporally with decreases in both total and high-density lipoprotein phospholipid.

Conclusions—

In humans, plasma inflammatory markers are directly correlated with plasma EL concentrations, and experimental endotoxemia significantly increases plasma EL concentrations, proving that EL is upregulated by inflammation in humans. This mechanism may partially explain the low high-density lipoprotein cholesterol levels seen in obesity and metabolic syndrome.
Impact of Salusin-α and -β on Human Macrophage Foam Cell Formation and Coronary Atherosclerosis
Authors: Watanabe Takuya , Nishio Kae , Kanome Tomoko , Matsuyama Taka-aki , Koba Shinji , Sakai Tetsuo , Sato Kengo , Hongo Shigeki , Nose Kiyoshi , Ota Hidekazu , Kobayashi Youichi , Katagiri Takashi , Shichiri Masayoshi , Miyazaki Akira
Published: January 2008

Background—

Human salusins, related bioactive polypeptides with mitogenic effects on vascular smooth muscle cells and fibroblasts and roles in hemodynamic homeostasis, may be involved in the origin of coronary atherosclerosis. Macrophage foam cell formation, characterized by cholesterol ester accumulation, is modulated by scavenger receptor (cholesterol influx), acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1; storage cholesterol ester converted from free cholesterol), and ATP-binding cassette transporter A1 (cholesterol efflux).

Methods and Results—

Serum salusin-α levels were decreased in 173 patients with angiographically proven coronary artery disease compared with 40 patients with mild hypertension and 55 healthy volunteers (4.9±0.6 versus 15.4±1.1 and 20.7±1.5 pmol/L, respectively;
P
<0.0001). Immunoreactive salusin-α and -β were detected in human coronary atherosclerotic plaques, with dominance of salusin-β in vascular smooth muscle cells and fibroblasts. After 7 days in primary culture, acetylated low-density lipoprotein–induced cholesterol ester accumulation in human monocyte-derived macrophages was significantly decreased by salusin-α and increased by salusin-β. Salusin-α significantly reduced ACAT-1 expression in a concentration-dependent manner. In contrast, salusin-β significantly increased ACAT-1 expression by 2.1-fold, with a maximal effect at 0.6 nmol/L. These effects of salusins were abolished by G-protein, c-Src tyrosine kinase, protein kinase C, and mitogen-activated protein kinase kinase inhibitors. ACAT activity and ACAT-1 mRNA levels were also significantly decreased by salusin-α and increased by salusin-β; however, neither salusin-α nor salusin-β affected scavenger receptor A function assessed by [
125
I]acetylated low-density lipoprotein endocytosis or scavenger receptor class A and ATP-binding cassette transporter A1 expression.

Conclusions—

Our results indicate that the 2 salusin isoforms have opposite effects on foam cell formation in human monocyte-derived macrophages. Development of atherosclerosis may be accelerated by salusin-β and suppressed by salusin-α via ACAT-1 regulation.
Visceral Adipose Tissue Inflammation Accelerates Atherosclerosis in Apolipoprotein E–Deficient Mice
Authors: Öhman Miina K. , Shen Yuechun , Obimba Chinyere I. , Wright Andrew P. , Warnock Mark , Lawrence Daniel A. , Eitzman Daniel T.
Published: January 2008

Background—

Fat inflammation may play an important role in comorbidities associated with obesity such as atherosclerosis.

Methods and Results—

To first establish feasibility of fat transplantation, epididymal fat pads were harvested from wild-type C57BL/6J mice and transplanted into leptin-deficient (
Lep

ob/ob

) mice. Fat transplantation produced physiological leptin levels and prevented obesity and infertility in
Lep

ob/ob

mice. However, the transplanted fat depots were associated with chronically increased macrophage infiltration with characteristics identical to those observed in fat harvested from obese animals. The inflammation in transplanted adipose depots was regulated by the same factors that have been implicated in endogenous fat inflammation such as monocyte chemoattractant protein-1. To determine whether this inflamed adipose depot could affect vascular disease in mice, epididymal fat depots were transplanted into atherosclerosis-prone apolipoprotein E–deficient

ApoE
−/−

mice. Plasma from

ApoE
−/−

mice receiving fat transplants contained increased leptin, resistin, and monocyte chemoattractant protein-1 compared with plasma from sham-operated

ApoE
−/−

mice. Furthermore, mice transplanted with visceral fat developed significantly more atherosclerosis compared with sham-operated animals, whereas transplants with subcutaneous fat did not affect atherosclerosis despite a similar degree of fat inflammation. Treatment of transplanted

ApoE
−/−

mice with pioglitazone decreased macrophage content of the transplanted visceral fat pad and reduced plasma monocyte chemoattractant protein-1. Importantly, pioglitazone also reduced atherosclerosis triggered by inflammatory visceral fat but had no protective effect on atherosclerosis in the absence of the visceral fat transplantation.

Conclusions—

Our results indicate that visceral adipose-related inflammation accelerates atherosclerosis in mice. Drugs such as thiazolidinediones might be a useful strategy to specifically attenuate the vascular disease induced by visceral inflammatory fat.
Critical Role of Donor Tissue Expression of Programmed Death Ligand-1 in Regulating Cardiac Allograft Rejection and Vasculopathy
Authors: Yang Jun , Popoola Joyce , Khandwala Shakila , Vadivel Nidyanandh , Vanguri Vijay , Yuan Xueli , Dada Shirine , Guleria Indira , Tian Chaorui , Ansari M. Javeed , Shin Tahiro , Yagita Hideo , Azuma Miyuki , Sayegh Mohamed H. , Chandraker Anil
Published: January 2008

Background—

Allograft vasculopathy is a major limiting factor in the long-term success of cardiac transplantation. T cells play a critical role in initiation of cardiac allograft rejection and allograft vasculopathy. The negative T-cell costimulatory pathway PD-1:PDL1/PDL2 (programmed death-1:programmed death ligand-1/2) plays an important role in regulating alloimmune responses. We investigated the role of recipient versus donor PD-1 ligands in the pathogenesis of allograft rejection with emphasis on the role of tissue expression in regulating this alloimmune response in vivo.

Methods and Results—

We used established major histocompatibility complex class II– and class I–mismatched models of vascularized cardiac allograft rejection, blocking anti-PDL1 and anti-PDL2 antibodies, and PDL1- and PDL2-deficient mice (as donors or recipients) to study the role of the PD-1:PDL1/PDL2 pathway in chronic rejection. We also used PDL1-deficient and wild-type mice and bone marrow transplantation to generate chimeric animals that express PDL1 exclusively on either hematopoietic or parenchymal cells. PDL1 but not PDL2 blockade significantly accelerated cardiac allograft rejection in the bm12-into-B6 and B6-into-bm12 models. Although wild-type cardiac allografts survived long term, PDL1
−/−
donor hearts transplanted into wild-type bm12 mice exhibited accelerated rejection and vasculopathy associated with enhanced recipient T-cell alloreactivity. Interestingly, PDL1
−/−
recipients did not exhibit an accelerated tempo of cardiac allograft rejection. Using chimeric animals as donors, we show that PDL1 expression on cardiac tissue alone significantly prolonged graft survival compared with full PDL1
−/−
donor grafts in transplanted wild-type recipients.

Conclusions—

This is the first report to demonstrate that expression of the negative costimulatory molecule PDL1 on donor cardiac tissue regulates recipient alloimmune responses, allograft rejection, and vasculopathy.
Oxidative Stress in Mononuclear Cells Plays a Dominant Role in Their Adhesion to Mouse Femoral Artery After Injury
Authors: Hagita Sumihiko , Osaka Mizuko , Shimokado Kentaro , Yoshida Masayuki
Published: January 2008

Leukocyte recruitment plays a pivotal role during inflammation after vascular injury. The importance of oxidative stress in vascular injury and its modulation by angiotensin II receptor blockers (olmesartan) have been demonstrated. We examined the contribution of leukocyte-associated oxidative stress in acute-phase leukocyte recruitment and its modulation by olmesartan. Male mice were treated with olmesartan (5 mg/kg per day) or vehicle for 7 days before the transluminal wire injury of the femoral artery. Intravital microscopy of the artery revealed that the mechanical injury increased adherent leukocytes at both 24 hours and 7 days after the injury, which was significantly reduced by olmesartan treatment. Dihydroethidium-associated fluorescence intensity observed in vehicle-treated mice was significantly diminished under olmesartan treatment. Apocynin, a nicotinamide-adenine dinucleotide phosphate oxidase inhibitor, showed a similar inhibitory effect on the leukocyte adhesion. Adoptive transfer of mononuclear cells, harvested from mice after wire injury, but not from those without wire injury, exhibited adhesion to the recipient injured artery. Furthermore, olmesartan treatment of mononuclear cells, but not of injured vasculature, reduced their recruitment to the injured artery. These data indicate that leukocyte recruitment to the mechanically injured artery is mediated by oxidative stress in leukocytes but not in vasculatures. Treatment with olmesartan blocked leukocyte recruitment by antagonizing mononuclear cells-associated oxidative stress.
(Pro)Renin Receptor Peptide Inhibitor “Handle-Region” Peptide Does Not Affect Hypertensive Nephrosclerosis in Goldblatt Rats
Authors: Muller Dominik N. , Klanke Bernd , Feldt Sandra , Cordasic Nada , Hartner Andrea , Schmieder Roland E. , Luft Friedrich C. , Hilgers Karl F.
Published: January 2008

The (pro)renin receptor [(P)RR], a new component the renin-angiotensin system, was cloned recently. The (P)RR promotes direct mitogen-activated protein kinase signaling and nonproteolytic prorenin activation. We investigated the role of a (P)RR blocker, a peptide consisting of 10 amino acids from the prorenin prosegment called the “handle-region” peptide (HRP), on target organ damage in renovascular hypertensive 2-kidney, 1-clip (2K1C) rats. Vehicle-treated 2K1C rats were compared with HRP-treated 2K1C rats (3.5 μg/kg per day) and sham-operated controls. Vehicle-treated 2K1C rats developed hypertension (186±17 mm Hg), cardiac hypertrophy (3.16±0.16 mg/g), renal inflammation, fibrosis, vascular, and tubular damage. Chronic HRP treatment did not affect blood pressure (194±15 mm Hg), cardiac hypertrophy (2.97±0.11 mg/g), or renal damage. Furthermore, we investigated the renal renin and (P)RR expression. The clipped kidney of 2K1C and HRP-treated 2K1C rats showed a higher renin expression and juxtaglomerular index compared with sham-operated kidneys. The unclipped kidney showed suppressed renin expression. In contrast, (P)RR mRNA expression was not altered in any group. Plasma renin activity and aldosterone were increased in 2K1C rats compared with sham controls. HRP-treated 2K1C rats tended to lower plasma renin activity but showed similar aldosterone levels as vehicle-treated 2K1C rats. Our results indicate that blockade of the (P)RR with HRP does not improve target organ damage in renovascular hypertensive rats.
Impacts of Measurement Protocols on Blood Pressure Tracking From Childhood Into Adulthood
Authors: Chen Xiaoli , Wang Youfa , Appel Lawrence J. , Mi Jie
Published: January 2008

The best approach for blood pressure (BP) measurement in children remains controversial, specifically regarding the choice of Korotkoff phase 4 versus Korotkoff phase 5 for diastolic BP (DBP) and the use of automated devices. To examine the impacts of different BP measurement protocols on BP tracking from childhood into adulthood, we conducted a meta-analysis of 50 related studies published between 1970 and 2006 identified based on a systematic search of PubMed. These studies provided 617 data points (tracking correlation coefficient, our outcome variable) for systolic BP and 547 data points for DBP for our meta-analysis. The explanatory variables included the use of Korotkoff phase 4/Korotkoff phase 5, BP device, and number of BP measurements per visit. Analyses were adjusted for potential confounders, including sex, baseline age, follow-up length, publication year, and study country. Tracking correlation coefficients for DBP measured using Korotkoff phase 4 was higher than that of Korotkoff phase 5 by 0.035 but not significant. DBP tracking assessed by automated device was higher than that of Korotkoff phase 5 by 0.152 (
P
=0.024) and higher than the mercury manometer by 0.223 (
P
=0.005). BP tracking was slightly higher with multiple BP measurements per visit, but measurements of ≥3 times did not improve the tracking further compared with 2 measurements. Although policy-making bodies currently recommend the use of Korotkoff phase 5 to assess DBP in children, our metaregression analysis did not support the recommendation. In general, Korotkoff phase 4 seems to be different from Korotkoff phase 5, and automated device is a promising approach for BP assessment in childhood.
Prognostic Significance of Between-Arm Blood Pressure Differences
Authors: Agarwal Rajiv , Bunaye Zerihun , Bekele Dagim M.
Published: January 2008

Blood pressure (BP) recordings often differ between arms, but the extent to which these differences are reproducible and whether the differences have prognostic importance is unknown. We enrolled 421 consecutive patients from a medicine and a renal clinic at a veterans’ hospital. Three BP recordings were obtained in each arm using an oscillometric device in a sequential manner and repeated in 1 week. Patients were followed for all-cause mortality ≤7 years. The right arm had 5.1-mm Hg higher systolic BP that attenuated by ≈2.2 mm Hg a week later. Systolic BP dropped 6.9 mm Hg over 1 week and by an additional 5.3 mm Hg in patients with chronic kidney disease. Accounting for the visit and arm effect improved the reproducibility of the BP measurements. The intraclass correlation coefficient was 0.74, which improved to 0.88 after accounting for visit and 0.93 after accounting for arm. The crude mortality rate was 6.33 per 100 patient-years. Every 10-mm Hg difference in systolic BP between the arms conferred a mortality hazard of 1.24 (95% CI: 1.01 to 1.52) after adjusting for average systolic BP and chronic kidney disease. BP differences between arms are reproducible and carry prognostic information. Patients should have evaluation of BP in both arms at the screening visit.
Defining an Adequate Education for English Learners
Authors: Gándara Patricia , Rumberger Russell W.
Published: January 2008

This article explores the components of an “adequate” education for linguistic minority students in California and attempts to distinguish these from the components of an adequate education for low-income students who are native English speakers. About 1.6 million students were classified as English learners (ELs) in California in 2006. We argue that in order to determine the costs of educating these students, it is necessary to specify the goals of instruction. Four possible goals are: (1) reclassification to fluent English proficient (FEP) only; (2) reclassification to FEP and maintenance of academic proficiency; (3) reclassification with biliteracy; and (4) reclassification and closing of achievement gaps. Each goal implies different resource needs. We conclude that most additional resources needed by EL students are similar to those for other low-income children; some specific areas of need that differ are English language development (ELD) materials and additional skills for teachers. Biliteracy can be achieved with modest additional investment.
Online Learning with Hidden Markov Models
Authors: Mongillo Gianluigi , Deneve Sophie
Published: February 2008

We present an online version of the expectation-maximization (EM) algorithm for hidden Markov models (HMMs). The sufficient statistics required for parameters estimation is computed recursively with time, that is, in an online way instead of using the batch forward-backward procedure. This computational scheme is generalized to the case where the model parameters can change with time by introducing a discount factor into the recurrence relations. The resulting algorithm is equivalent to the batch EM algorithm, for appropriate discount factor and scheduling of parameters update. On the other hand, the online algorithm is able to deal with dynamic environments, i.e., when the statistics of the observed data is changing with time. The implications of the online algorithm for probabilistic modeling in neuroscience are briefly discussed.
Stochastic Backscatter for Cloud-Resolving Models. Part I: Implementation and Testing in a Dry Convective Boundary Layer
Authors: Weinbrecht Sonja , Mason Paul J.
Published: January 2008

In simulations of deep convection with cloud-resolving models the turbulence is often rather poorly resolved, and the influence of the subfilter-scale parameterization used in such circumstances is probably greater than in better-resolved simulations. Therefore a study to investigate the influence of stochastic backscatter was performed and presented in two papers. This first paper focuses on a description of the stochastic backscatter model and its effect on a neutral and a dry convective boundary layer. The second paper then deals with two cases of deep convection.

The dry convective boundary layer is typical of the subcloud layer in deep convection and this study allows for influences on this layer to be investigated separately. As a simple case of convection it also allows for general effects to be identified. The implementation of stochastic backscatter was improved to ensure an appropriate scale of backscatter that is independent of any mesh refinements and always spatially isotropic. It can also be applied in a deep atmosphere with use of the anelastic approximation.

Generally the backscatter is found to affect the velocity and scalar variances as well as the spatial structure and time development of the simulations. An additional issue is the marked influence of both varying resolution and backscatter on the near-surface temperature differences. This is an element of the complex issue of surface transfers under free convection conditions. Overall, the investigations show that the backscatter gives some beneficial changes to the simulations, which tend to keep results in less well- resolved cases closer to those in better-resolved simulations.
Axial Atmospheric Angular Momentum Budget at Diurnal and Subdiurnal Periodicities
Authors: Lott François , de Viron Olivier , Viterbo Pedro , Vial François
Published: January 2008

The diurnal and subdiurnal variations of the mass and wind terms of the axial atmospheric angular momentum (AAM) are explored using a 1-yr integration of the Laboratoire de Météorologie Dynamique (LMDz) GCM, twelve 10-day ECMWF forecasts, and some ECMWF analysis products. In these datasets, the wind and mass AAMs present diurnal and semidiurnal oscillations for which tendencies far exceed the total torque.

In the LMDz GCM, these diurnal and semidiurnal oscillations are associated with axisymmetric (s = 0) and barotropic circulation modes that resemble the second gravest (n = 2) eigensolution of Laplace’s tidal equations. This mode induces a Coriolis conversion from the wind AAM toward the mass AAM that far exceeds the total torque. At the semidiurnal period, this mode dominates the axisymmetric and barotropic circulation. At the diurnal period, this n = 2 mode is also present, but the barotropic circulation also presents a mode resembling the first gravest n = 1 eigensolution of the tidal equations. This last mode does not produce anomalies in the mass and wind AAMs.

A shallow-water axisymmetric model driven by zonal mean zonal forces, for which the vertical integral equals the zonal mean zonal stresses issued from the GCM, is then used to interpret these results. This model reproduces well the semidiurnal oscillations in mass and wind AAM, and the semidiurnal mode resembling the n = 2 eigensolution that produces them, when the forcing is distributed barotropically in the vertical direction. This model also reproduces diurnal modes resembling the n = 1 and n = 2 eigensolutions when the forcings are distributed more baroclinically. Among the dynamical forcings that produce these modes of motion, it is found that the mountain forcing and the divergence of the AAM flux are equally important and are more efficient than the boundary layer friction.

In geodesy, the large but opposite signals in the mass and wind AAM due to the n = 2 modes can lead to large errors in the evaluation of the AAM budget. The n = 2 responses in surface pressure can affect the earth ellipcity, and the n = 1 diurnal response can affect the geocenter position. For the surface pressure tide, the results suggest that the dynamical forcings of the zonal-mean zonal flow are a potential cause for its s = 0 component.
Limits, Variability, and General Behavior of Statistical Predictability of the Midlatitude Atmosphere
Authors: Kleeman Richard
Published: January 2008

The nature of statistical predictability is analyzed in a T42 global atmospheric model that is able to adequately capture the main features of the midlatitude atmosphere. Key novel features of the present study include very large prediction ensembles and information theoretic techniques. It is found globally that predictability declines in a quasi-linear fashion with time for short-term predictions (3–25 days), while for long ranges (30–45 days) there is an exponential tail. In general, beyond 45 days the prediction and climatological ensembles have essentially converged, which means that beyond that point, atmospheric initial conditions are irrelevant to atmospheric statistical prediction.

Regional predictions show considerable variation in behavior. Both of the (northern) winter storm-track regions show a close-to-quasi-linear decline in predictability toward a cutoff at around 40 days. The (southern) summer storm track shows a much more exponential and considerably slower decline with a small amount of predictability still in evidence even at 90 days. Because the winter storm tracks dominate global variance the behavior of their predictability tends to dominate the global measure, except at longer lags. Variability in predictability with respect to initial conditions is also examined, and it is found that this is related more strongly to ensemble signal rather than ensemble spread. This result may serve to explain why the relation between weather forecast skill and ensemble spread is often observed to be significantly less than perfect. Results herein suggest that the ensemble signal as well as spread variations may be a major contributor to skill variations. Finally, it is found that the sensitivity of the calculated global predictability to changes in model horizontal resolution is not large; results from a T85 resolution model are not qualitatively all that different from the T42 case.
Emission of Inertial Waves by Baroclinically Unstable Flows: Laboratory Experiments with Altimetric Imaging Velocimetry
Authors: Afanasyev Y. D. , Rhines P. B. , Lindahl E. G.
Published: January 2008

Results from new experiments on baroclinic instability of a coastal jet demonstrate that this almost balanced flow spontaneously emits inertial waves when the Rossby radius of deformation is relatively small such that the characteristics of baroclinic meanders match the dispersion relation for the inertial waves. The energy of the waves is small compared to the energy of the flow. A single event of wave emission is identified in the experiment with larger radius of deformation and is interpreted in terms of vorticity dynamics. The flows are generated on a laboratory polar β plane where the Coriolis parameter varies quadratically with latitude. A new method for imaging the rotating flows, which the authors call “altimetric imaging velocimetry,” is employed. Optical color coding of slopes of the free-surface elevation field allows the authors to derive the fields of pressure, surface elevation, geostrophic velocity, or the “gradient wind” velocity with very high spatial resolution (typically several million vectors) limited largely by the pixel resolution of the available imaging sensors. The technique is particularly suited for the investigations of small-amplitude waves, which are often difficult to detect by other methods.
The Effect of Dynamics on Mixed-Phase Clouds: Theoretical Considerations
Authors: Korolev Alexei , Field Paul R.
Published: January 2008

A theoretical framework has been developed describing nonequilibrium formation and maintenance of mixed-phase clouds. The necessary and sufficient conditions required to activate liquid water within a preexisting ice cloud, and thus convert it to mixed phase, are considered for three scenarios: (i) uniform ascent, (ii) harmonic vertical oscillations, and (iii) turbulent fluctuations. The general conditions are the following:First necessary condition: The vertical velocity of an ice cloud parcel must exceed a threshold velocity to activate liquid water.Second necessary condition: The activation of liquid water within an ice cloud parcel, below water saturation, requires a vertical ascent above some threshold altitude to bring the vapor pressure of the parcel to water saturation.

Only when the first and second conditions are true do these conditions become sufficient for the activation of liquid water in ice clouds. These required conditions for the generation of mixed-phase cloud are supported by parcel modeling results and analogous conditions for a harmonic oscillation concerning the amplitude and tangential velocity of the parcel motion are proposed. The authors do not assume steady-state conditions, but demonstrate that nonequilibrium evolution of cloud parcels can lead to long-term steady existence of mixed-phase cloud.
Parameter Sweep Experiments on Spontaneous Gravity Wave Radiation from Unsteady Rotational Flow in an f-Plane Shallow Water System
Authors: Sugimoto Norihiko , Ishioka Keiichi , Ishii Katsuya
Published: January 2008

Inertial gravity wave radiation from an unsteady rotational flow (spontaneous radiation) is investigated numerically in an f-plane shallow water system for a wide range of Rossby numbers, 1 ≤ Ro ≤ 1000, and Froude numbers, 0.1 ≤ Fr ≤ 0.8. A barotropically unstable jet flow is initially balanced and maintained by forcing so that spontaneous gravity wave radiation is generated continuously. The amount of gravity wave flux is proportional to Fr for large Ro(≥30), which is consistent with the power law of the aeroacoustic sound wave radiation theory (the Lighthill theory). In contrast, for small Ro(≤10) this power law does not hold because of the vortex stabilization due to the small deformation radius. In the case of fixed Fr, gravity wave flux is almost constant for larger Ro(>30) and decreases rapidly for smaller Ro(<5). There is a local maximum value between these Ro(∼10). Spectral frequency analysis of the gravity wave source shows that for Ro = 10, while the source term related to the earth’s rotation is larger than that related to unsteady rotational flow, the inertial cutoff frequency is still lower than the peak frequency of the dominant source. The results suggest that the effect of the earth’s rotation may intensify spontaneous gravity wave radiation for Ro ∼ 10.