bluuebunny/crossref_metadata_2025 huggingface dataset:
RECONSIDERING THE QUANTIZATION OF ELECTRODYNAMICS WITH BOUNDARY CONDITIONS
Authors: BORDAG M.
Published: June 2005

We show that the commonly known conductor boundary conditions E‖ = B⊥ = 0 can be realized in two ways which we call 'thick' and 'thin' conductor. The 'thick' conductor is the commonly known approach and includes a Neumann condition on the normal component E⊥ of the electric field whereas for a 'thin' conductor E⊥ remains without boundary condition. Both types describe different physics already on the classical level where a 'thin' conductor allows for an interaction between the normal components of currents on both sides. On quantum level different forces between a conductor and a single electron or a neutral atom result. For instance, the Casimir-Polder force for a 'thin' conductor is by about 13% smaller than for a 'thick' one.
ENDOPLASMIC RETICULUM–ASSOCIATED DEGRADATION
Authors: Römisch Karin
Published: June 2005

Secretory and transmembrane proteins enter the secretory pathway through the protein-conducting Sec61 channel in the membrane of the endoplasmic reticulum. In the endoplasmic reticulum, proteins fold, are frequently covalently modified, and oligomerize before they are packaged into transport vesicles that shuttle them to the Golgi complex. Proteins that misfold in the endoplasmic reticulum are selectively transported back across the endoplasmic reticulum membrane to the cytosol for degradation by proteasomes. Depending on the topology of the defect in the protein, cytosolic or lumenal chaperones are involved in its targeting to degradation. The export channel for misfolded proteins is likely also formed by Sec61p. Export may be powered by AAA-ATPases of the proteasome 19S regulatory particle or Cdc48p/p97. Exported proteins are frequently ubiquitylated prior to degradation and are escorted to the proteasome by polyubiquitin-binding proteins.
INTEGRIN STRUCTURE, ALLOSTERY, AND BIDIRECTIONAL SIGNALING
Authors: Arnaout M.A. , Mahalingam B. , Xiong J.-P.
Published: June 2005

αβ heterodimeric integrins mediate dynamic adhesive cell-cell and cell-extracellular matrix (ECM) interactions in metazoa that are critical in growth and development, hemostasis, and host defense. A central feature of these receptors is their capacity to change rapidly and reversibly their adhesive functions by modulating their ligand-binding affinity. This is normally achieved through interactions of the short cytoplasmic integrin tails with intracellular proteins, which trigger restructuring of the ligand-binding site through long-range conformational changes in the ectodomain. Ligand binding in turn elicits conformational changes that are transmitted back to the cell to regulate diverse responses. The publication of the integrin αVβ3 crystal structure has provided the context for interpreting decades-old biochemical studies. Newer NMR, crystallographic, and EM data, reviewed here, are providing a better picture of the dynamic integrin structure and the allosteric changes that guide its diverse functions.
REGULATION OF ROOT APICAL MERISTEM DEVELOPMENT
Authors: Jiang Keni , Feldman Lewis J.
Published: June 2005

The establishment of the Angiosperm root apical meristem is dependent on the specification of a stem cell niche and the subsequent development of the quiescent center at the presumptive root pole. Distribution of auxin and the establishment of auxin maxima are early formative steps in niche specification that depend on the expression and distribution of auxin carriers. Auxin specifies stem cell niche formation by directly and indirectly affecting gene activities. Part of the indirect regulation by auxin may involve changes in redox, favoring local, oxidized microenvironments. Formation of a QC is required for root meristem development and elaboration. Many signals likely pass between the QC and the adjacent root meristem tissues. Disappearance of the QC is associated with roots becoming determinate. Given the many auxin feedback loops, we hypothesize that roots evolved as part of an auxin homeostasis mechanism.
SPATIAL CONTROL OF CELL EXPANSION BY THE PLANT CYTOSKELETON
Authors: Smith Laurie G. , Oppenheimer David G.
Published: June 2005

The cytoskeleton plays important roles in plant cell shape determination by influencing the patterns in which cell wall materials are deposited. Cortical microtubules are thought to orient the direction of cell expansion primarily via their influence on the deposition of cellulose into the wall, although the precise nature of the microtubule-cellulose relationship remains unclear. In both tip-growing and diffusely growing cell types, F-actin promotes growth and also contributes to the spatial regulation of growth. F-actin has been proposed to play a variety of roles in the regulation of secretion in expanding cells, but its functions in cell growth control are not well understood. Recent work highlighted in this review on the morphogenesis of selected cell types has yielded substantial new insights into mechanisms governing the dynamics and organization of cytoskeletal filaments in expanding plant cells and how microtubules and F-actin interact to direct patterns of cell growth. Nevertheless, many important questions remain to be answered.
fMRI Activation in the Human Frontal Eye Field Is Correlated With Saccadic Reaction Time
Authors: Connolly Jason D. , Goodale Melvyn A. , Goltz Herbert C. , Munoz Douglas P.
Published: June 2005

Variation in response latency to identical sensory stimuli has been attributed to variation in neural activity mediating preparatory set. Here we report evidence for a relationship between saccadic reaction time (SRT) and set-related brain activity measured with event-related functional magnetic resonance imaging. We measured hemodynamic activation time-courses during a preparatory “gap” period, during which no visual stimulus was present and no saccades were made. The subjects merely anticipated appearance of the target. Saccade direction and latency were recorded during scanning, and trials were sorted according to SRT. Both the frontal (FEF) and supplementary eye fields showed pretarget preparatory activity, but only in the FEF was this activity correlated with SRT. Activation in the intraparietal sulcus did not show any preparatory activity. These data provide evidence that the human FEF plays a central role in saccade initiation; pretarget activity in this region predicts both the type of eye movement (whether the subject will look toward or away from the target) and when a future saccade will occur.
Calcium-Stimulated Adenylyl Cyclases Required for Long-Term Potentiation in the Anterior Cingulate Cortex
Authors: Liauw Jason , Wu Long-Jun , Zhuo Min
Published: June 2005

Activity-dependent long-term potentiation (LTP) in the CNS is thought to be important in learning, memory, development, and persistent pain. Here, we report that NMDA receptor-dependent LTP is the major form of long-term plasticity in the anterior cingulate cortex (ACC). In addition to N-methyl-d-aspartate (NMDA) receptors, L-type voltage-gated calcium channels are also required for inducing LTP. Activation of calcium-stimulated adenylyl cyclase subtype 1 (AC1) is essential for the induction of LTP in ACC neurons, while AC8 subunit partially contributes to forskolin-induced potentiation. Our results suggest that calcium-stimulated cAMP-dependent signaling pathways play a critical role in cingulate LTP.
Effects of Noncardiovascular Comorbidities on Antihypertensive Use in Elderly Hypertensives
Authors: Wang Philip S. , Avorn Jerry , Brookhart M. Alan , Mogun Helen , Schneeweiss Sebastian , Fischer Michael A. , Glynn Robert J.
Published: June 2005

Although the benefits of antihypertensive drugs have been clearly established, they remain underused by vulnerable older populations. We examined whether the presence of noncardiovascular comorbidity deters use of antihypertensives in elderly with hypertension. We conducted a retrospective cohort study among 51 517 patients ≥65 years of age in the Pennsylvania Pharmaceutical Assistance Contract for the Elderly (PACE) Program during 1999 and 2000. All were hypertensive and had diagnoses and used treatments during 1999 to qualify for entry into 1 of the following 5 mutually exclusive cohorts: asthma/chronic obstructive pulmonary disease (COPD), depression, gastrointestinal (GI) disorders, osteoarthritis, or none of the 4 comorbidities. Proportions using antihypertensives in 2000 were assessed. Logistic regression analysis was used to identify the independent effects on antihypertensive use of the 4 comorbidities of interest, sociodemographic characteristics, other cardiovascular and noncardiovascular comorbidity, and health care utilization variables. After adjustments in multivariable analyses, antihypertensive use was consistently lower in patients with asthma/COPD (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.40 to 0.47), depression (OR, 0.50; 95% CI, 0.45 to 0.55), GI disorders (OR, 0.59; 95% CI, 0.54 to 0.64), and osteoarthritis (OR, 0.63; 95% CI, 0.59 to 0.67) relative to those without these conditions. Reduced antihypertensive use was also associated with older age, female gender, white race, more severe other comorbidities, absence of some cardiovascular indications, hospitalizations, nursing home care, physician visits, and use of fewer other medications. Highly prevalent, noncardiovascular conditions appear to deter use of antihypertensives in elderly with hypertension.
Risk of Embolism and Death in Infective Endocarditis: Prognostic Value of Echocardiography
Authors: Thuny Franck , Disalvo Giovanni , Belliard Olivier , Avierinos Jean-François , Pergola Valeria , Rosenberg Valerie , Casalta Jean-Paul , Gouvernet Joanny , Derumeaux Geneviève , Iarussi Diana , Ambrosi Pierre , Calabro Raffaello , Riberi Alberto , Collart Frédéric , Metras Dominique , Lepidi Hubert , Raoult Didier , Harle Jean-Robert , Weiller Pierre-Jean , Cohen Ariel , Habib Gilbert
Published: June 2005

Background—

The incidence of embolic events (EE) and death is still high in patients with infective endocarditis (IE), and data about predictors of these 2 major complications are conflicting. Moreover, the exact role of echocardiography in risk stratification is not well defined.

Methods and Results—

In a multicenter prospective European study, including 384 consecutive patients (aged 57±17 years) with definite IE according to Duke University criteria, we tested clinical, microbiological, and echocardiographic data as potential predictors of EE and 1-year mortality. Transesophageal echocardiography was performed in all patients. Embolism occurred before or after IE diagnosis (total-EE) in 131 patients (34.1%) and after initiation of antibiotic therapy (new-EE) in 28 patients (7.3%).
Staphylococcus aureus
and
Streptococcus bovis
were independently associated with total-EE, whereas vegetation length >10 mm and severe vegetation mobility were predictors of new-EE, even after adjustment for
S aureus
and
S bovis
. One-year mortality was 20.6%. In multivariable analysis, independently of the other predictors of death (age, female sex, creatinine serum >2 mg/L, moderate or severe congestive heart failure, and
S aureus
) and comorbidity, vegetation length >15 mm was a predictor of 1-year mortality (adjusted relative risk=1.8; 95% CI, 1.10 to 2.82;
P
=0.02).

Conclusions—

In IE, vegetation length is a strong predictor of new-EE and mortality. In combination with clinical and microbiological findings, echocardiography may identify high-risk patients who will need a more aggressive therapeutic strategy.
C-Reactive Protein and the 10-Year Incidence of Coronary Heart Disease in Older Men and Women
Authors: Cushman Mary , Arnold Alice M. , Psaty Bruce M. , Manolio Teri A. , Kuller Lewis H. , Burke Gregory L. , Polak Joseph F. , Tracy Russell P.
Published: June 2005

Background—

High C-reactive protein (CRP) is associated with increased coronary heart disease risk. Few long-term data in the elderly are available.

Methods and Results—

Baseline CRP was measured in 3971 men and women ≥65 years of age without prior vascular diseases; 26% had elevated concentrations (>3 mg/L). With 10 years of follow-up, 547 participants developed coronary heart disease (CHD; defined as myocardial infarction or coronary death). With elevated CRP, the 10-year cumulative CHD incidences were 33% in men and 17% in women. The age-, ethnicity-, and sex-adjusted relative risk of CHD for CRP >3 mg/L compared with <1 mg/L was 1.82 (95% CI, 1.46 to 2.28). Adjusting for conventional risk factors reduced the relative risk to 1.45 (95% CI, 1.14 to 1.86). The population-attributable risk of CHD for elevated CRP was 11%. Risk relationships did not differ in subgroups defined by baseline risk factors. We assessed whether CRP improved prediction by the Framingham Risk Score. Among men with a 10-year Framingham-predicted risk of 10% to 20%, the observed CHD incidence was 32% for elevated CRP. Among women, CRP discriminated best among those with a 10-year predicted risk >20%; the incidences were 31% and 10% for elevated and normal CRP levels, respectively.

Conclusions—

In older men and women, elevated CRP was associated with increased 10-year risk of CHD, regardless of the presence or absence of cardiac risk factors. A single CRP measurement provided information beyond conventional risk assessment, especially in intermediate-Framingham-risk men and high-Framingham-risk women.
In Vivo Cell Seeding With Anti-CD34 Antibodies Successfully Accelerates Endothelialization but Stimulates Intimal Hyperplasia in Porcine Arteriovenous Expanded Polytetrafluoroethylene Grafts
Authors: Rotmans Joris I. , Heyligers Jan M.M. , Verhagen Hence J.M. , Velema Evelyn , Nagtegaal Machiel M. , de Kleijn Dominique P.V. , de Groot Flip G. , Stroes Erik S.G. , Pasterkamp Gerard
Published: June 2005

Background—

The patency of AV expanded polytetrafluoroethylene (ePTFE) grafts for hemodialysis is impaired by intimal hyperplasia (IH) at the venous outflow tract. The absence of a functional endothelial monolayer on the prosthetic grafts is an important stimulus for IH. In the present study, we evaluated the feasibility of capturing endothelial progenitor cells in vivo using anti-CD34 antibodies on ePTFE grafts to inhibit IH in porcine AV ePTFE grafts.

Methods and Results—

In 11 pigs, anti-CD34–coated ePTFE grafts were implanted between the carotid artery and internal jugular vein. Bare ePTFE grafts were implanted at the contralateral side. After 3 (n=2) or 28 (n=9) days, the pigs were terminated, and the AV grafts were excised for histological analysis and SEM. At 3 and 28 days after implantation, 95% and 85% of the coated graft surface was covered by endothelial cells. In contrast, no cell coverage was observed in the bare graft at 3 days, whereas at 28 days, bare grafts were partly covered with endothelial cells (32%;
P
=0.04). Twenty-eight days after implantation, IH at the venous anastomosis was strongly increased in anti-CD34–coated grafts (5.96±1.9 mm
2
) compared with bare grafts (1.70±0.4 mm
2
;
P
=0.03). This increase in IH coincided with enhanced cellular proliferation at the venous anastomosis.

Conclusions—

Autoseeding with anti-CD34 antibodies results in rapid endothelialization within 72 hours. Despite persistent endothelial graft coverage, IH at the outflow tract is increased profoundly at 4 weeks after implantation. Further modifications are required to stimulate the protective effects of trapped endothelial cells.
Nuclear Magnetic Resonance Lipoprotein Abnormalities in Prediabetic Subjects in the Insulin Resistance Atherosclerosis Study
Authors: Festa Andreas , Williams Ken , Hanley Anthony J.G. , Otvos James D. , Goff David C. , Wagenknecht Lynne E. , Haffner Steven M.
Published: June 2005

Background—

Subjects with type 2 diabetes have smaller LDL and HDL particles in addition to higher levels of triglycerides and lower HDL cholesterol. Elevated insulin resistance, blood pressure, and dyslipidemia (including small dense LDL) predicted incident diabetes. In the Insulin Resistance Atherosclerosis Study (IRAS) we studied nuclear magnetic resonance (NMR) lipoprotein particle measures in prediabetic individuals, considering potentially modifying covariates, including insulin resistance, as directly measured using a frequently sampled intravenous glucose tolerance test.

Methods and Results—

Of 830 subjects who were nondiabetic at baseline, 130 (15.7%) developed diabetes after a mean follow-up of 5.2 years. Various lipoprotein abnormalities were found in prediabetic subjects compared with subjects who stayed nondiabetic at follow-up. In logistic regression analyses (demographically adjusted), VLDL particles, large VLDL, LDL particles, small LDL, large HDL, small HDL, VLDL size, LDL size, and HDL size were related to incident diabetes. The relation of VLDL size and small HDL to incident diabetes was independent of waist (odds ratio [OR] [95% CI], 1.43 [1.18 to 1.73] and 1.23 [1.01 to 1.51] for VLDL size and small HDL, respectively) and independent of conventionally (chemically) measured triglycerides and HDL cholesterol (OR [95% CI], 1.45 [1.18 to 1.78] and 1.30 [1.06 to 1.60], respectively). Insulin sensitivity attenuated the relation to incident diabetes of VLDL size (OR [95% CI], 1.25 [1.01 to 1.53]) but not of small HDL particles (OR [95% CI], 1.25 [1.02 to 1.54]).

Conclusions—

We have shown a range of lipoprotein abnormalities in prediabetic individuals, including compositional changes in HDL and VLDL. These findings extend previous work indicating a proatherogenic state in healthy, nondiabetic subjects who subsequently develop diabetes.
Obesity, Insulin Resistance, and the Metabolic Syndrome
Authors: Lteif A.A. , Han K. , Mather K.J.
Published: June 2005

Background—

Insulin resistance is strongly associated with obesity and other components of the metabolic syndrome (MS). The relative importance of these components in the determination of endothelial function is unknown. Furthermore, there is conflicting evidence about whether ethnic differences exist in the relative importance of these components in regard to other cardiovascular outcomes. We evaluated the contributions of insulin resistance, obesity, and the other components of the MS to impaired endothelial function.

Methods and Results—

The relationships of the MS components (as defined according the National Cholesterol Education Program) and insulin resistance (estimated using the homeostasis model) with endothelium-dependent vasodilation were examined in 42 white and 55 black subjects. Endothelium-dependent vasodilation was assessed as the increment in leg blood flow (measured by thermodilution) after exposure to methacholine chloride. Waist circumference, glucose, blood pressure, and insulin resistance distributions did not differ between ethnic groups; blacks in our sample had higher HDL cholesterol (1.31 versus 1.09 mmol/L;
P
<0.001) and lower triglyceride levels (1.01 versus 1.37 mmol/L;
P
=0.005) than white subjects. In the absence of the MS, black subjects exhibited reduced endothelium-dependent vasodilation compared with white subjects (
P
=0.005), and both groups demonstrated significantly worse endothelial function when the MS was present (maximal increase in leg blood flow: blacks: 107±9% MS absent, 53±16% MS present; whites: 163±16% MS absent, 54±18% MS absent;
P
=0.007, MS absent versus present;
P
=NS for interaction of ethnicity and MS). Multivariable regression analysis examining relationships of endothelial function with the 5 MS components (analyzed as continuous variables) revealed independent relationships only with waist circumference (
P
=0.01) and systolic blood pressure (
P
=0.02). Waist circumference was no longer independently associated after adding insulin resistance to the modeling (
P
=0.02 for log of homeostasis model index of insulin resistance,
P
=0.02 for systolic blood pressure). Ethnicity still exerted an independent effect on endothelial function after accounting for the above components (
P
=0.04 for an additional effect of ethnic status on endothelial function), with an ethnic difference in the effect of insulin resistance on endothelial function (
P
=0.046 for interaction of ethnicity and log of homeostasis model index of insulin resistance).

Conclusions—

These findings suggest that insulin resistance and systolic blood pressure are the principal determinants of endothelial dysfunction in the MS and that there are ethnic differences in the relative importance of these factors. These differences may imply different benefits from treatments targeting blood pressure or insulin resistance in different ethnic groups.
Effects of Candesartan on the Development of a New Diagnosis of Diabetes Mellitus in Patients With Heart Failure
Authors: Yusuf Salim , Ostergren Jan B. , Gerstein Hertzel C. , Pfeffer Marc A. , Swedberg Karl , Granger Christopher B. , Olofsson Bertil , Probstfield Jeffrey , McMurray John V.
Published: June 2005

Background—

Diabetes is a risk factor for heart failure, and both conditions are increasing. Identifying treatments that prevent both conditions will be clinically important. We previously reported that candesartan (an angiotensin receptor blocker) reduces cardiovascular mortality and heart failure hospitalizations in heart failure patients (CHARM:
C
andesartan in
H
eart Failure—
A
ssessment of
R
eduction in
M
ortality and Morbidity Program).

Methods and Results—

We assessed the impact of candesartan versus placebo on the development of diabetes, a predefined secondary outcome in a randomized, controlled, double-blind study involving 5436 of the 7601 patients with heart failure, irrespective of ejection fraction, who did not have a diagnosis of diabetes at entry into the trial. Patients received candesartan (target of 32 mg once daily) or matching placebo for 2 to 4 years. One hundred sixty-three (6.0%) individuals in the candesartan group developed diabetes, as compared with 202 (7.4%) in the placebo group (hazard ratio [HR], 0.78 with a 95% confidence interval [CI] of 0.64 to 0.96;
P
=0.020). The composite end point of death or diabetes occurred in 692 (25.2%) and 779 (28.6%), respectively, in the candesartan and placebo groups (HR, 0.86; 95% CI, 0.78 to 0.95;
P
=0.004). The results were not statistically heterogeneous in the various subgroups examined, although the apparent magnitude of benefit appeared to be smaller among those treated concomitantly with angiotensin-converting enzyme inhibitors at trial entry (HR, 0.88; 95% CI, 0.65 to 1.20) compared with those not receiving these drugs (HR, 0.71; 95% CI, 0.53 to 0.93;
P
for heterogeneity, 0.28).

Conclusions—

The angiotensin receptor blocker candesartan appears to prevent diabetes in heart failure patients, suggesting that the renin-angiotensin axis is implicated in glucose regulation.
Bcl-xL Gene Transfer Inhibits Bax Translocation and Prolongs Cardiac Cold Preservation Time in Rats
Authors: Huang Jianhua , Nakamura Kiminori , Ito Yoshinori , Uzuka Takeshi , Morikawa Masayuki , Hirai Sachie , Tomihara Kei , Tanaka Toshihiro , Masuta Yukari , Ishii Keiji , Kato Kazunori , Hamada Hirofumi
Published: June 2005

Background—

Apoptosis is an important cause of early graft loss after heart transplantation. Bcl-xL was reported to protect the heart against normothermic ischemia and reperfusion injury. In this study, we determined whether overexpression of Bcl-xL could inhibit tissue injury resulting from prolonged cold preservation followed by warm reperfusion of heart transplants.

Methods and Results—

Lewis rat hearts were transduced with an adenovirus vector harboring Bcl-xL cDNA (AxCAhBclxL) 4 days before collection of tissue. After preservation in University of Wisconsin solution at 4°C for 24 hours, the heart was either perfused with a Langendorff device ex vivo or used for heterotopic heart transplantation in vivo. Bcl-xL gene transfer significantly reduced the infarct size (23.0±2.6% versus 47.7±7.0% in saline control and 48.6±6.1% in vector control,
P
<0.01) after 2-hour reperfusion at 37°C with the Langendorff device and significantly decreased creatine kinase release (0.82±0.27 IU, versus 1.57±0.33 and 1.50±0.37 IU in saline and vector controls, respectively;
P
<0.05). In heart transplantation, overexpresson of Bcl-xL inhibited Bax translocation from the cytosol to the mitochondria, resulting in decreased cytochrome
c
release from the mitochondria; it also significantly decreased cardiac cell apoptosis and improved graft survival rate after long cold preservation, followed by warm reperfusion.

Conclusions—

Bcl-xL gene transfer inhibited the translocation of Bax and prolonged the cold preservation time of cardiac transplants. This may be a potential therapeutic method in clinical practice.
Pathophysiology of Coronary Artery Disease
Authors: Libby Peter , Theroux Pierre
Published: June 2005

During the past decade, our understanding of the pathophysiology of coronary artery disease (CAD) has undergone a remarkable evolution. We review here how these advances have altered our concepts of and clinical approaches to both the chronic and acute phases of CAD. Previously considered a cholesterol storage disease, we currently view atherosclerosis as an inflammatory disorder. The appreciation of arterial remodeling (compensatory enlargement) has expanded attention beyond stenoses evident by angiography to encompass the biology of nonstenotic plaques. Revascularization effectively relieves ischemia, but we now recognize the need to attend to nonobstructive lesions as well. Aggressive management of modifiable risk factors reduces cardiovascular events and should accompany appropriate revascularization. We now recognize that disruption of plaques that may not produce critical stenoses causes many acute coronary syndromes (ACS). The disrupted plaque represents a “solid-state” stimulus to thrombosis. Alterations in circulating prothrombotic or antifibrinolytic mediators in the “fluid phase” of the blood can also predispose toward ACS. Recent results have established the multiplicity of “high-risk” plaques and the widespread nature of inflammation in patients prone to develop ACS. These findings challenge our traditional view of coronary atherosclerosis as a segmental or localized disease. Thus, treatment of ACS should involve 2 overlapping phases: first, addressing the culprit lesion, and second, aiming at rapid “stabilization” of other plaques that may produce recurrent events. The concept of “interventional cardiology” must expand beyond mechanical revascularization to embrace preventive interventions that forestall future events.
A Global Merged Land–Air–Sea Surface Temperature Reconstruction Based on Historical Observations (1880–1997)
Authors: Smith Thomas M. , Reynolds Richard W.
Published: June 2005

A merged land–air–sea surface temperature reconstruction analysis is developed for monthly anomalies. The reconstruction is global and spatially complete. Reconstructed anomalies damp toward zero in regions with insufficient sampling. Error estimates account for the damping associated with sparse sampling, and also for bias uncertainty in both the land and sea observations. Averages of the reconstruction are similar to simple averages of the unanalyzed data for most of the analysis period. For the nineteenth century, when sampling is most sparse and the error estimates are largest, the differences between the averaged reconstruction and the simple averages are largest. Sampling is always sparse poleward of 60° latitude, and historic reconstructions for the polar regions should be used with caution.
Tropical Pacific–Driven Decadel Energy Transport Variability
Authors: Hazeleger Wilco , Severijns Camiel , Seager Richard , Molteni Franco
Published: June 2005

The atmospheric energy transport variability associated with decadal sea surface temperature variability in the tropical Pacific is studied using an atmospheric primitive equation model coupled to a slab mixed layer. The decadal variability is prescribed as an anomalous surface heat flux that represents the reduced ocean heat transport in the tropical Pacific when it is anomalously warm. The atmospheric energy transport increases and compensates for the reduced ocean heat transport. Increased transport by the mean meridional overturning (i.e., the strengthening of the Hadley cells) causes increased poleward energy transport. The subtropical jets increase in strength and shift equatorward, and in the midlatitudes the transients are affected. NCEP–NCAR reanalysis data show that the warming of the tropical Pacific in the 1980s compared to the early 1970s seems to have caused very similar changes in atmospheric energy transport indicating that these atmospheric transport variations were driven from the tropical Pacific. To study the implication of these changes for the coupled climate system an ocean model is driven with winds obtained from the atmosphere model. The poleward ocean heat transport increased when simulated wind anomalies associated with decadal tropical Pacific variability were used, showing a negative feedback between decadal variations in the mean meridional circulation in the atmosphere and in the Pacific Ocean. The Hadley cells and subtropical cells act to stabilize each other on the decadal time scale.
On the Meridional Structure of Annular Modes
Authors: Wittman Matthew A. H. , Charlton Andrew J. , Polvani Lorenzo M.
Published: June 2005

Using a simple stochastic model, the authors illustrate that the occurrence of a meridional dipole in the first empirical orthogonal function (EOF) of a time-dependent zonal jet is a simple consequence of the north–south excursion of the jet center, and this geometrical fact can be understood without appealing to fluid dynamical principles. From this it follows that one ought not, perhaps, be surprised at the fact that such dipoles, commonly referred to as the Arctic Oscillation (AO) or the Northern Annular Mode (NAM), have robustly been identified in many observational studies and appear to be ubiquitous in atmospheric models across a wide range of complexity.
Mechanisms Forcing an Antarctic Dipole in Simulated Sea Ice and Surface Ocean Conditions
Authors: Holland Marika M. , Bitz Cecilia M. , Hunke Elizabeth C.
Published: June 2005

The mechanisms forcing variability in Southern Ocean sea ice and sea surface temperature from 600 years of a control climate coupled model integration are discussed. As in the observations, the leading mode of simulated variability exhibits a dipole pattern with positive anomalies in the Pacific sector associated with negative anomalies in the Atlantic. It is found that in the Pacific ocean circulation changes associated with variable wind forcing modify the ocean heat flux convergence and sea ice transport, resulting in sea surface temperature and sea ice anomalies. The Pacific ice and ocean anomalies persist over a number of years due to reductions in ocean shortwave absorption reinforcing the initial anomalies. In the Atlantic sector, no single process dominates in forcing the anomalies. Instead there are contributions from changing ocean and sea ice circulation and surface heat fluxes. While the absorbed solar radiation in the Atlantic is modified by the changing surface albedo, the anomalies are much shorter-lived than in the Pacific because the ocean circulation transports them northward, removing them from ice formation regions. Sea ice and ocean anomalies associated with the El Niño–Southern Oscillation and the Southern Annular Mode both exhibit a dipole pattern and contribute to the leading mode of ice and ocean variability.
Simulated Tropical Response to a Substantial Weakening of the Atlantic Thermohaline Circulation
Authors: Zhang Rong , Delworth Thomas L.
Published: June 2005

In this study, a mechanism is demonstrated whereby a large reduction in the Atlantic thermohaline circulation (THC) can induce global-scale changes in the Tropics that are consistent with paleoevidence of the global synchronization of millennial-scale abrupt climate change. Using GFDL’s newly developed global coupled ocean–atmosphere model (CM2.0), the global response to a sustained addition of freshwater to the model’s North Atlantic is simulated. This freshwater forcing substantially weakens the Atlantic THC, resulting in a southward shift of the intertropical convergence zone over the Atlantic and Pacific, an El Niño–like pattern in the southeastern tropical Pacific, and weakened Indian and Asian summer monsoons through air–sea interactions.
New WSR-88D Volume Coverage Pattern 12: Results of Field Tests
Authors: Brown Rodger A. , Wood Vincent T. , Steadham Randy M. , Lee Robert R. , Flickinger Bradley A. , Sirmans Dale
Published: June 2005

For the first time since the installation of the national network of Weather Surveillance Radar-1988 Doppler (WSR-88D), a new scanning strategy—Volume Coverage Pattern 12 (VCP 12)—has been added to the suite of scanning strategies. VCP 12 is a faster version of VCP 11 and has denser vertical sampling at lower elevation angles. This note discusses results of field tests in Oklahoma and Mississippi during 2001–03 that led to the decision to implement VCP 12. Output from meteorological algorithms for a test-bed radar using an experimental VCP were compared with output for a nearby operational WSR-88D using VCP 11 or 21. These comparisons were made for severe storms that were at comparable distances from both radars. Findings indicate that denser vertical sampling at lower elevation angles leads to earlier and longer algorithm identifications of storm cells and mesocyclones, especially those more distant from a radar.
Verification of Precipitation Forecasts from Two Limited-Area Models over Italy and Comparison with ECMWF Forecasts Using a Resampling Technique
Authors: Accadia Christophe , Mariani Stefano , Casaioli Marco , Lavagnini Alfredo , Speranza Antonio
Published: June 2005

This paper presents the first systematic limited area model (LAM) precipitation verification work over Italy. A resampling technique was used to provide skill score results along with confidence intervals. Two years of data were used, starting in October 2000. Two operational LAMs have been considered, the Limited Area Model Bologna (LAMBO) operating at the Agenzia Regionale Prevenzione e Ambiente-Servizio Meteorologico Regionale (ARPA-SMR) of the Emilia–Romagna region, and the QUADRICS Bologna Limited Area Model (QBOLAM) running at the Agenzia per la Protezione dell’Ambiente e per i Servizi Tecnici (APAT). A 24-h forecast skill score comparison was first performed on the native 0.1° high-resolution grids, using a Barnes scheme to produce the observed 24-h accumulated rainfall analysis. Two nonparametric skill scores were used: the equitable threat score (ETS) and the Hanssen and Kuipers score (HK). Frequency biases (BIA) were also calculated. LAM forecasts were also remapped on a lower-resolution grid (0.5°), using a nearest-neighbor average method; this remapping allowed for comparison with ECMWF model forecasts, and for LAM intercomparisons at lower resolution, with the advantage of reducing the skill score sensitivity to small displacements errors. LAM skill scores depend on the resolution of the verification grid, with an increase when they are verified on a lower-resolution grid. The selected LAMs have a higher BIA compared to ECMWF, showing a tendency to overforecast precipitation, especially along mountain ranges, possibly due to undesired effects from the large-scale and/or convective precipitation parameterizations. Lower ECMWF BIA accounts for skill score differences. LAMBO precipitation forecasts during winter (adjusted for BIA differences) have less misses than ECMWF over the islands of Sardinia and Sicily. Higher-resolution orography definitely adds value to LAM forecasts.
Linking the Eta Model with the Community Multiscale Air Quality (CMAQ) Modeling System to Build a National Air Quality Forecasting System
Authors: Otte Tanya L. , Pouliot George , Pleim Jonathan E. , Young Jeffrey O. , Schere Kenneth L. , Wong David C. , Lee Pius C. S. , Tsidulko Marina , McQueen Jeffery T. , Davidson Paula , Mathur Rohit , Chuang Hui-Ya , DiMego Geoff , Seaman Nelson L.
Published: June 2005

NOAA and the U.S. Environmental Protection Agency (EPA) have developed a national air quality forecasting (AQF) system that is based on numerical models for meteorology, emissions, and chemistry. The AQF system generates gridded model forecasts of ground-level ozone (O3) that can help air quality forecasters to predict and alert the public of the onset, severity, and duration of poor air quality conditions. Although AQF efforts have existed in metropolitan centers for many years, this AQF system provides a national numerical guidance product and the first-ever air quality forecasts for many (predominantly rural) areas of the United States. The AQF system is currently based on NCEP’s Eta Model and the EPA’s Community Multiscale Air Quality (CMAQ) modeling system. The AQF system, which was implemented into operations at the National Weather Service in September of 2004, currently generates twice-daily forecasts of O3 for the northeastern United States at 12-km horizontal grid spacing. Preoperational testing to support the 2003 and 2004 O3 forecast seasons showed that the AQF system provided valuable guidance that could be used in the air quality forecast process. The AQF system will be expanded over the next several years to include a nationwide domain, a capability for forecasting fine particle pollution, and a longer forecast period. State and local agencies will now issue air quality forecasts that are based, in part, on guidance from the AQF system. This note describes the process and software components used to link the Eta Model and CMAQ for the national AQF system, discusses several technical and logistical issues that were considered, and provides examples of O3 forecasts from the AQF system.
The Use of Moisture Flux Convergence in Forecasting Convective Initiation: Historical and Operational Perspectives
Authors: Banacos Peter C. , Schultz David M.
Published: June 2005

Moisture flux convergence (MFC) is a term in the conservation of water vapor equation and was first calculated in the 1950s and 1960s as a vertically integrated quantity to predict rainfall associated with synoptic-scale systems. Vertically integrated MFC was also incorporated into the Kuo cumulus parameterization scheme for the Tropics. MFC was eventually suggested for use in forecasting convective initiation in the midlatitudes in 1970, but practical MFC usage quickly evolved to include only surface data, owing to the higher spatial and temporal resolution of surface observations. Since then, surface MFC has been widely applied as a short-term (0–3 h) prognostic quantity for forecasting convective initiation, with an emphasis on determining the favorable spatial location(s) for such development.

A scale analysis shows that surface MFC is directly proportional to the horizontal mass convergence field, allowing MFC to be highly effective in highlighting mesoscale boundaries between different air masses near the earth’s surface that can be resolved by surface data and appropriate grid spacing in gridded analyses and numerical models. However, the effectiveness of boundaries in generating deep moist convection is influenced by many factors, including the depth of the vertical circulation along the boundary and the presence of convective available potential energy (CAPE) and convective inhibition (CIN) near the boundary. Moreover, lower- and upper-tropospheric jets, frontogenesis, and other forcing mechanisms may produce horizontal mass convergence above the surface, providing the necessary lift to bring elevated parcels to their level of free convection without connection to the boundary layer. Case examples elucidate these points as a context for applying horizontal mass convergence for convective initiation. Because horizontal mass convergence is a more appropriate diagnostic in an ingredients-based methodology for forecasting convective initiation, its use is recommended over MFC.
Resource Dependence, Economic Performance, and Political Stability
Authors: Dunning Thad
Published: June 2005

In many resource-dependent states, elites may face an important trade-off between the economic benefits of diversification and the possibility for future political competition that diversification may engender. However, distinctive features of global resource markets and national political economies may make diversification more or less attractive to political elites. The author argues that in three cases which illustrate the equilibrium paths of the game-theoretic model developed here—postindependence Bostwana, Mobutu’s Zaire, and Suharto’s Indonesia—three variables influenced elites’ incentives for diversification and thereby shaped outcomes along the dimensions of political stability and economic performance: the world market structure for the resource, the degree of societal opposition to elites, and the prior development of the nonresource private sector. These countries’ varied paths from resource wealth to political and economic outcomes suggest the need for conditional theories of the resource curse.
Natural Resources, Conflict, and Conflict Resolution
Authors: Humphreys Macartan
Published: June 2005

The interpretation of the resource-conflict link that has become most publicized—the rebel greed hypothesis—depends on just one of many plausible mechanisms that could underlie a relationship between resource dependence and violence. The author catalogues a large range of rival possible mechanisms, highlights a set of techniques that may be used to identify these mechanisms, and begins to employ these techniques to distinguish between rival accounts of the resource-conflict linkages. The author uses finer natural resource data than has been used in the past, gathering and presenting new data on oil and diamonds production and on oil stocks. The author finds evidence that (1) conflict onset is more responsive to the impacts of past natural resource production than to the potential for future production, supporting a weak states mechanism rather than a rebel greed mechanism; (2) the impact of natural resources on conflict cannot easily be attributed entirely to the weak states mechanism, and in particular, the impact of natural resources is independent of state strength; (3) the link between primary commodities and conflict is driven in part by agricultural dependence rather than by natural resources more narrowly defined, a finding consistent with a “sparse networks” mechanism; (4) natural resources are associated with shorter wars, and natural resource wars are more likely to end with military victory for one side than other wars. This is consistent with evidence that external actors have incentives to work to bring wars to a close when natural resource supplies are threatened. The author finds no evidence that resources are associated with particular difficulties in negotiating ends to conflicts, contrary to arguments that loot-seeking rebels aim to prolong wars.
A Diamond Curse?
Authors: Lujala Päivi , Gleditsch Nils Petter , Gilmore Elisabeth
Published: June 2005

While territory, oil, and water are frequently mentioned as resources likely to promote interstate conflict, diamonds have emerged as a prominent factor in explanations of civil war. In this article, the authors report on a new database on diamond deposits and production and analyze the relationship between diamonds and armed conflict incidence. They find a strong bivariate relationship between diamonds (particularly secondary diamonds) and the onset of civil war. Adding diamond dummies to standard models of civil war, the results are more mixed. The production of secondary diamonds increases the risk of onset of ethnic war, but not other types of war. The authors find evidence that secondary diamonds are positively related to the incidence of civil war, especially in countries divided along ethnic lines. Primary diamonds, on the other hand, make ethnic war onset and incidence less likely. The authors also find that the impact of diamonds has been substantially stronger in the post-cold war era.
Comparison of the Educational Deficiencies of Delinquent and Nondelinquent Students
Authors: Wang Xia , Blomberg Thomas G. , Li Spencer D.
Published: June 2005

This article assesses the differences in educational deficiencies between a statewide sample of delinquent students and a matched sample of nondelinquent students. Employing a research design that controls for a series of relevant individual and school variables, the study’s findings document that delinquent students are characterized by a series of disproportionate educational deficiencies as compared to their nondelinquent student counterparts. Delinquent students were found to attain lower grade point averages, have poorer school attendance records, be retained more often in the same grade, and receive more school disciplinary actions. The article concludes that these documented educational deficiencies may play an integral role in the process of delinquency and, therefore, pose a number of public policy implications in relation to the prevention and treatment of delinquency.
Major Factors Influencing HIV/AIDS Project Evaluation
Authors: Niba Mercy Bi , Green J. Maryann
Published: June 2005

This article aimed at finding out if participatory processes (group discussions, enactments, and others) do make a valuable contribution in communication-based project implementation/evaluation and the fight against HIV/AIDS. A case study backed by documentary analysis of evaluation reports and occasional insights from interviews stood as the main methods. To identify values, the state of beneficiaries prior to and after project implementation/evaluation was compared. Participatory processes were noted to have created an enabling environment for project beneficiaries to become activists for social change, leading to the limiting of the spread of HIV/AIDS through sexual behavior and a change of attitude—the essence required for successful intervention. Group participatory processes were also noted to have contributed in overriding, to a great extent, limitations arising from sociodemographic differences in the attainment of project objectives and limitations arising from differences in forms of evaluation (internal versus external evaluators).
Modeling Lactococcus lactis using a genome-scale flux model
Authors: Oliveira Ana Paula , Nielsen Jens , Förster Jochen
Published: June 2005

Background

Genome-scale flux models are useful tools to represent and analyze microbial metabolism. In this work we reconstructed the metabolic network of the lactic acid bacteria Lactococcus lactis and developed a genome-scale flux model able to simulate and analyze network capabilities and whole-cell function under aerobic and anaerobic continuous cultures. Flux balance analysis (FBA) and minimization of metabolic adjustment (MOMA) were used as modeling frameworks.

Results

The metabolic network was reconstructed using the annotated genome sequence from L. lactis ssp. lactis IL1403 together with physiological and biochemical information. The established network comprised a total of 621 reactions and 509 metabolites, representing the overall metabolism of L. lactis. Experimental data reported in the literature was used to fit the model to phenotypic observations. Regulatory constraints had to be included to simulate certain metabolic features, such as the shift from homo to heterolactic fermentation. A minimal medium for in silico growth was identified, indicating the requirement of four amino acids in addition to a sugar. Remarkably, de novo biosynthesis of four other amino acids was observed even when all amino acids were supplied, which is in good agreement with experimental observations. Additionally, enhanced metabolic engineering strategies for improved diacetyl producing strains were designed.

Conclusion

The L. lactis metabolic network can now be used for a better understanding of lactococcal metabolic capabilities and potential, for the design of enhanced metabolic engineering strategies and for integration with other types of 'omic' data, to assist in finding new information on cellular organization and function.