bluuebunny/crossref_metadata_2025 huggingface dataset:
Accounting for the increase in NSAID expenditure: substitution or leakage?
Authors: Barton Garry R , Avery Anthony J , Whynes David K
Published: May 2006

Background

National Institute of Health and Clinical Excellence (NICE) guidance stated that a new form of non-steroidal anti-inflammatory drug (NSAID) (selective COX-2 inhibitors) should only be an option for arthritis patients at high risk of a gastro-intestinal (GI) event. Total expenditure on NSAIDs has risen by 57% over five years, to £247 million in 2004. We assess whether this expenditure increase can be accounted for by substitution – an increased prescribing of two (more expensive) selective COX-2 inhibitors (celecoxib and rofecoxib) and a simultaneous equivalent reduction in the prescribing volume of three (cheaper) older NSAIDs (diclofenac, ibuprofen and naproxen).

Methods

Quarterly prescription data was collated from January 1999 to September 2004. Over this period, the level of correlation between the total prescribing volumes for i) celecoxib and rofecoxib, and ii) diclofenac, ibuprofen, and naproxen were compared, the change in total expenditure on the five NSAIDs was also estimated. The latter was apportioned into that which was estimated to have arisen due to i) substitution, and ii) increased NSAID prescription volume.

Results

Total prescription volumes for the two NSAID groups were negatively correlated (r = -0.97, p < 0.001). In the last quarter there were 1.23 million prescriptions for celecoxib and rofecoxib, and 0.46 million fewer prescriptions for naproxen, diclofenac, and ibuprofen (than in the first quarter, when celecoxib and rofecoxib were not prescribed). Total expenditure for the five NSAIDs was £32.7 million higher in the last quarter, than the first, £12.2 million of which was estimated to be due to substitution, and £20.4 million due to increased volume.

Conclusion

The introduction of celecoxib and rofecoxib was associated with a reduction in the prescription volume for naproxen, diclofenac, and ibuprofen. However, overall quarterly prescription volume for these five NSAIDs increased by 0.76 million, and we estimate that quarterly expenditure increased by £20.4 million more than would have been expected if overall NSAID volume had remained constant. This suggests that the prescription of both celecoxib and rofecoxib may have 'leaked' to population groups who would not previously have received an older NSAID.
Similarity searches in genome-wide numerical data sets
Authors: Glazko Galina , Coleman Michael , Mushegian Arcady
Published: May 2006

We present psi-square, a program for searching the space of gene vectors. The program starts with a gene vector, i.e., the set of measurements associated with a gene, and finds similar vectors, derives a probabilistic model of these vectors, then repeats search using this model as a query, and continues to update the model and search again, until convergence. When applied to three different pathway-discovery problems, psi-square was generally more sensitive and sometimes more specific than the ad hoc methods developed for solving each of these problems before.

Reviewers

This article was reviewed by King Jordan, Mikhail Gelfand, Nicolas Galtier and Sarah Teichmann.
Clinical Benefits of Subgingival Chlorhexidine Varnish Application as an Adjunct to Same‐Day Full‐Mouth Root Planing: A Pilot Study
Authors: Cosyn Jan , Wyn Iris , De Rouck Tim , Moradi Sabzevar Mehran
Published: May 2006

Background: Although scaling and root planing are considered the therapeutic standard for periodontitis, weakly responding sites often occur. To improve treatment outcome, several chemomechanical treatment concepts have been developed. Recently, the clinical surplus value of a highly concentrated chlorhexidine varnish has been shown when used as an adjunct to sequential scaling and root planing. The aim of this study was to explore the clinical effects of a treatment strategy for chronic periodontitis based on a combination of same‐day full‐mouth root planing and subgingival chlorhexidine varnish administration.

Methods: A randomized, controlled, single‐blind, parallel trial was conducted on 12 chronic periodontitis patients. The control group received oral hygiene instructions and same‐day full‐mouth root planing. The test group received the same instructions and treatment; however, all pockets were additionally disinfected using a chlorhexidine varnish. Clinical response parameters were recorded at baseline and subsequently after 1 and 3 months.

Results: Both treatment strategies showed significant reductions in probing depth at both follow‐up visits in comparison with baseline levels (P ≤0.029). Yet, at 3 months, initially diseased sites of the test group showed significant additional pocket reductions between 0.70 and 1.37 mm (P ≤0.021). Furthermore, a significant additive clinical attachment gain of 1.17 mm (P = 0.049) for initially deep pockets (≥7 mm) was found favoring the test group.

Conclusion: These preliminary findings suggest that the outcome of same‐day full‐mouth root planing may benefit from the subgingival administration of a highly concentrated chlorhexidine varnish.
Dimension of Interproximal Soft Tissue Between Adjacent Implants in Two Distinctive Implant Systems
Authors: Lee Dong‐Won , Park Kwang‐Ho , Moon Ik‐Sang
Published: May 2006

Background: The purpose of this study was to compare the dimension of interproximal soft tissue between adjacent implants in distinctive implant systems.

Methods: This study involved 85 interproximal papillae between two adjacent implants in 50 patients who had implants placed adjacent to each other and who had prosthesis in place for longer than 1 year. The shortest distance between the radiopaque material on the tip of interimplant papilla and the most coronal portion of the interimplant crestal bone was measured (radiographic length of papilla [RL]). The horizontal distance (HD) between the two adjacent implants was measured at the fixture‐abutment interface level. Considering the possible effect of interimplant crestal bone resorption on closely implanted sites, HDs were divided into two categories: HD <3 and ≥3 mm. The Mann‐Whitney test was performed to find the difference in the dimension of interimplant papilla.

Results: In cases of HD <3 mm, RL did not differ statistically in both systems. Also, in cases of HD >3 mm, RL did not show a statistically significant difference in both systems.

Conclusion: Both systems had similar dimensions of interproximal soft tissue between adjacent implants, irrespective of the horizontal distance of the fixture.
Minority Group Status and Healthful Aging: Social Structure Still Matters
Authors: Angel Jacqueline L. , Angel Ronald J.
Published: May 2006

During the last 4 decades, a rapid increase has occurred in the number of survey-based and epidemiological studies of the health profiles of adults in general and of the causes of disparities between majority and minority Americans in particular. According to these studies, healthful aging consists of the absence of disease, or at least of the most serious preventable diseases and their consequences, and findings consistently reveal serious African American and Hispanic disadvantages in terms of healthful aging.

We (1) briefly review conceptual and operational definitions of race and Hispanic ethnicity, (2) summarize how ethnicity-based differentials in health are related to social structures, and (3) emphasize the importance of attention to the economic, political, and institutional factors that perpetuate poverty and undermine healthful aging among certain groups.
Conversion of elective laparoscopic to open cholecystectomy between 1993 and 2004
Authors: Ishizaki Y , Miwa K , Yoshimoto J , Sugo H , Kawasaki S
Published: May 2006

Background

Laparoscopic cholecystectomy (LC) is the standard treatment for symptomatic gallbladder disease. The identification of factors that reliably predict the likely need to convert LC to an open procedure would provide short-term benefits in terms of patient education and postoperative expectations.

Methods

Between 1993 and 2004, 1179 elective LCs were attempted from a total of 1339 elective cholecystectomies. The change in conversion rate between 1993–1999 and 2000–2004 was analysed. Factors predictive of higher risk for conversion were also identified.

Results

Eighty-nine LCs (7·5 per cent) required conversion. Gallbladder wall thickness and a history of common bile duct (CBD) stones, treated by preoperative endoscopic sphincterotomy, were predictors of conversion. The proportion of patients who underwent LC was the same in 1993–1999 (87·5 per cent) and 2000–2004 (88·8 per cent), but the conversion rate increased significantly from 5·3 to 10·6 per cent in these two time intervals. In addition, the proportion of patients with a history of CBD stones rose significantly, from 6·4 per cent in 1993–1999 to 11·0 per cent in 2000–2004.

Conclusion

The conversion rate increased over the 12-year interval of the study. A history of preoperative endoscopic sphincterotomy and a thickened gallbladder wall contributed to the likelihood of conversion.
Das allgemeine bauaufsichtliche Prüfzeugnis als Verwendbarkeits‐ und Anwendbarkeitsnachweis hinsichtlich der Anforderungen an den Schallschutz
Authors: Iffländer Frank
Published: May 2006

Wenn für Bauteile Anforderungen an den Schallschutz nach DIN 4109 bestehen, ist der Nachweis der Eignung gemäß Abschnitt 6.3 der Norm mit bauakustischen Messungen (Eignungsprüfungen) zu führen, wenn die Bauteile nicht den Ausführungsbeispielen nach Beiblatt 1 zu DIN 4109 entsprechen.

In der Liste der Technischen Baubestimmungen ist festgelegt, dass diese in DIN 4109 geforderten Eignungsprüfungen im Rahmen der Erteilung eines allgemeinen bauaufsichtlichen Prüfzeugnisses durchzuführen sind.

Für eine Vielzahl von Bauprodukten und Bauarten, die Anforderungen an den Schallschutz zu erfüllen haben, kommt daher dem allgemeinen bauaufsichtlichen Prüfzeugnis eine besondere Bedeutung zu.
Swelling and mechanical properties of glycol chitosan/poly(vinyl alcohol) IPN‐type superporous hydrogels
Authors: Park Hyojin , Kim Dukjoon
Published: May 2006

Glycol chitosan/poly(vinyl alcohol) interpenetrating polymer network type superporous hydrogels were prepared using a gas foaming/freeze‐drying method. The effect of the molecular weight of the strengthener, poly(vinyl alcohol) (PVA), on the swelling and mechanical behavior of the superporous hydrogels was investigated. The introduction of a small amount of high molecular weight PVA significantly enhanced the mechanical strength but slightly reduced the swelling capacity. The freezing/thawing (F/T) drying process had a significant effect on the physical properties of the glycol chitosan/PVA superporous hydrogels, because hydrogen bonds were formed between the PVA molecules as a result of the number of F/T cycles. The swelling ratio decreased but the mechanical strength increased with increasing freezing time. However, this effect was not as strong as the number of F/T cycles. The differential scanning calorimetry was used to examine how the thermal behavior associated with the hydrogen bond—induced crystalline structure was affected by the F/T process. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Measuring sense of community: A methodological interpretation of the factor structure debate
Authors: Peterson N. Andrew , Speer Paul W. , Hughey Joseph
Published: May 2006

Instability in the factor structure of the Sense of Community Index (SCI) was tested as a methodological artifact. Confirmatory factor analyses, tested with two data sets, supported neither the proposed one‐factor nor the four‐factor (needs fulfillment, group membership, influence, and emotional connection) SCI. Results demonstrated that the SCI was best described by four factors in combination with two method factors (i.e., one factor including only positively worded items and another including only negatively worded items). Analyses comparing SCI and method factors showed that positively and negatively worded items correlated differently with measures of citizen participation, psychological empowerment, and health‐related quality of life. Results indicate that the SCI should be revised to exclude negatively worded items and new positively worded items should be developed and tested. The effects of method variance and alternative solutions to the psychometric issues in the SCI are discussed. © 2006 Wiley Periodicals, Inc.
MUSTANG: A multiple structural alignment algorithm
Authors: Konagurthu Arun S. , Whisstock James C. , Stuckey Peter J. , Lesk Arthur M.
Published: May 2006

Multiple structural alignment is a fundamental problem in structural genomics. In this article, we define a reliable and robust algorithm, MUSTANG (MUltiple STructural AligNment AlGorithm), for the alignment of multiple protein structures. Given a set of protein structures, the program constructs a multiple alignment using the spatial information of the Cα atoms in the set. Broadly based on the progressive pairwise heuristic, this algorithm gains accuracy through novel and effective refinement phases. MUSTANG reports the multiple sequence alignment and the corresponding superposition of structures. Alignments generated by MUSTANG are compared with several handcurated alignments in the literature as well as with the benchmark alignments of 1033 alignment families from the HOMSTRAD database. The performance of MUSTANG was compared with DALI at a pairwise level, and with other multiple structural alignment tools such as POSA, CE‐MC, MALECON, and MultiProt. MUSTANG performs comparably to popular pairwise and multiple structural alignment tools for closely related proteins, and performs more reliably than other multiple structural alignment methods on hard data sets containing distantly related proteins or proteins that show conformational changes. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Dopamine D2 and D3 receptors in human putamen, caudate nucleus, and globus pallidus
Authors: Seeman Philip , Wilson Alan , Gmeiner Peter , Kapur Shitij
Published: May 2006

Because radioactive raclopride and radioactive (+)‐4‐propyl‐9‐hydroxynaphthoxazine ((+)‐PHNO) are used to image dopamine (DA) D2 and D3 receptors in the striatum and globus pallidus in humans, the present study examined the proportions of D2 and D3 receptors in postmortem tissues from these regions. Conflicting results were obtained when using a single concentration of remoxipride to occlude D2 receptors or using a single concentration of U99194A or FAUC 365 to occlude D3 receptors. However, using a range of concentrations of FAUC 365, a D3‐selective antagonist, to inhibit the binding [3H]raclopride or [3H]‐(+)‐PHNO to D3 receptors at low concentrations (1–10 nM) and to inhibit ligand binding to D2 receptors at higher concentrations (100–2000 nM), it was possible to measure the proportion of D2 and D3 receptors in the tissues. This method revealed that these two radioligands detected only D2 receptors in the dorsal putamen and the dorsal caudate nucleus, but detected a mixed population of two‐thirds D2 and one‐third D3 DA receptors in the ventral putamen, the ventral caudate, and the globus pallidus. The present findings are in good agreement with the known gene expression data for D2 and D3 receptors in these human brain regions. Synapse 60:205–211, 2006. © 2006 Wiley‐Liss, Inc.
Dissociable mechanisms for memory impairment in bipolar disorder and schizophrenia
Authors: GLAHN DAVID C. , BARRETT JENNIFER , BEARDEN CARRIE E. , MINTZ JIM , GREEN MICHAEL F. , SERAP MONKUL E. , NAJT PABLO , SOARES JAIR C. , VELLIGAN DAWN I.
Published: May 2006

Background. Although memory deficits are consistently reported in schizophrenia and bipolar disorder, the mechanisms underlying these impairments are poorly understood. Clarifying the nature and degree of overlap in memory deficits between the two illnesses could help to distinguish brain systems disrupted in these illnesses, and indicate cognitive remediation strategies to improve patient outcomes.

Method. We examined performance on a non-verbal memory task in clinically stable out-patients with bipolar disorder (n=40), schizophrenia (n=40), and healthy comparison subjects (n=40). This task includes conditions in which distinct mnemonic strategies – namely, using context to organize familiar stimuli or using holistic representation of novel stimuli – facilitate performance.

Result. When compared to a reference condition, bipolar patients had deficits consistent with organizational dysfunction and poor detection of novel information. Although patients with schizophrenia performed worse than the other groups, they were only differentially impaired when organizational demands were significant. Task performance was not correlated with severity of clinical symptomatology.

Conclusions. This pattern of distinct memory impairments implies disturbances in partially overlapping neural systems in bipolar disorder and schizophrenia. Evidence of impairment in detection of novel stimuli that is unique to bipolar disorder suggests that, while the absolute level of cognitive dysfunction is less severe in bipolar disorder as compared to schizophrenia, subtle disruptions in memory are present. These findings can be used to plan targeted cognitive remediation programs by helping patients to capitalize on intact functions and to learn new strategies that they do not employ without training.
Varying temporal criteria for generalized anxiety disorder: prevalence and clinical characteristics in a young age cohort
Authors: ANGST JULES , GAMMA ALEX , JOSEPH BIENVENU O. , EATON WILLIAM W. , AJDACIC VLADETA , EICH DOMINIQUE , RÖSSLER WULF
Published: May 2006

Background. This study questions the 6-month duration criterion for generalized anxiety disorder (GAD) used in DSM-III-R and DSM-IV.

Method. In adults from age 20/21 to 40/41 in the prospective Zurich Cohort Study, four groups of generalized anxiety syndromes defined by varying duration (2 weeks, 1 month, 3 months and 6 months) were compared.

Results. Applying DSM-III (1979–1999) and DSM-III-R (1986–1999) criteria, there were no significant differences between the four groups in terms of family history of anxiety, work impairment, distress, treatment rates or co-morbidity with major depressive episodes (MDEs), bipolar disorder or suicide attempts. Only social impairment related to the length of episodes. The 6-month criterion of DSM-III-R and DSM-IV GAD would preclude this diagnosis in about half of the subjects treated for generalized anxiety syndromes.

Conclusions. In this epidemiological sample, the 6-month duration criterion for GAD could not be confirmed as clinically meaningful. GAD syndromes of varying duration form a continuum with comparable clinical relevance.
Long‐term seismogenesis in Greece: Comparison of the evolving stress field and precursory scale increase approaches
Authors: Papadimitriou E. E. , Evison F. F. , Rhoades D. A. , Karakostas V. G. , Console R. , Murru M. R.
Published: May 2006

Recent strong (M≥ 6.6) earthquakes in Greece are examined from the point of view of two current, but disparate, approaches to long‐term seismogenesis. These are the evolving stress field (ESF) approach, in which earthquakes are considered to be triggered by accumulated stress changes from past earthquakes and tectonic loading on the major faults, and the precursory scale increase (Ψ) approach, in which a major earthquake is preceded in the long term by an increase in minor earthquake occurrences, with the magnitude of the precursory earthquakes, and the precursor time and area all scaling with the major earthquake magnitude. The strong earthquakes are found to be consistent with both approaches, and it is inferred that both approaches have a relevant role to play in the description of the long‐term generation process of major earthquakes. A three‐stage faulting model proposed previously to explain the Ψ phenomenon involves a major crack, which eventually fractures in the major earthquake, being formed before the onset of precursory seismicity. Hence we examine whether ESF can account for the formation of the major crack by examining the accumulated stress changes at the time of the onset of Ψ for each strong earthquake. In each case, the answer is in the affirmative; there is enhanced stress in the vicinity of the main shock at the time of the onset. The same is true for most, but not all, of the locations of precursory earthquakes.
Distribution, 14C chronology, and paleomagnetism of latest Pleistocene and Holocene lava flows at Haleakalā volcano, Island of Maui, Hawai‘i: A revision of lava flow hazard zones
Authors: Sherrod David R. , Hagstrum Jonathan T. , McGeehin John P. , Champion Duane E. , Trusdell Frank A.
Published: May 2006

New mapping and 60 new radiocarbon ages define the age and distribution of latest Pleistocene and Holocene (past 13,000 years) lava flows at Haleakalā volcano, Island of Maui. Paleomagnetic directions were determined for 118 sites, of which 89 are in lava flows younger than 13,000 years. The paleomagnetic data, in conjunction with a reference paleosecular variation (PSV) curve for the Hawaiian Islands, are combined with our knowledge of age limitations based on stratigraphic control to refine age estimates for some of the undated lava flows. The resulting volumetric rate calculations indicate that within analytical error, the extrusion rate has remained nearly constant during the past 13,000 years, in the range 0.05–0.15 km3/kyr, only about half the long‐term rate required to produce the postshield strata emplaced in the past ∼1 Myr. Haleakalā's eruptive frequency is similar to that of Hualālai volcano on the Island of Hawai‘i, but its lava flows cover substantially less area per unit time. The reduced rates of lava coverage indicate a lower volcanic hazard than in similar zones at Hualālai.
Regional climate model downscaling of the U.S. summer climate and future change
Authors: Liang Xin‐Zhong , Pan Jianping , Zhu Jinhong , Kunkel Kenneth E. , Wang Julian X. L. , Dai Aiguo
Published: May 2006

A mesoscale model (MM5)–based regional climate model (CMM5) integration driven by the Parallel Climate Model (PCM), a fully coupled atmosphere‐ocean‐land‐ice general circulation model (GCM), for the present (1986–1995) summer season climate is first compared with observations to study the CMM5's downscaling skill and uncertainty over the United States. The results indicate that the CMM5, with its finer resolution (30 km) and more comprehensive physics, simulates the present U.S. climate more accurately than the driving PCM, especially for precipitation, including summer mean patterns, diurnal cycles, and daily frequency distributions. Hence the CMM5 downscaling provides a credible means to improve GCM climate simulations. A parallel CMM5 integration driven by the PCM future (2041–2050) projection is then analyzed to determine the downscaling impact on regional climate changes. It is shown that the CMM5 generates climate change patterns very different from those predicted by the driving PCM. A key difference is a summer “warming hole” over the central United States in the CMM5 relative to the PCM. This study shows that the CMM5 downscaling can significantly reduce GCM biases in simulating the present climate and that this improvement has important consequences for future projections of regional climate changes. For both the present and future climate simulations, the CMM5 results are sensitive to the cumulus parameterization, with strong regional dependence. The deficiency in representing convection is likely the major reason for the PCM's unrealistic simulation of U.S. precipitation patterns and perhaps also for its large warming in the central United States.
Spatial distribution of carbonaceous aerosol in the southeastern United States using molecular markers and carbon isotope data
Authors: Zheng Mei , Ke Lin , Edgerton Eric S. , Schauer James J. , Dong Meiyu , Russell Armistead G.
Published: May 2006

Spatial variations of source contributions to fine organic carbon (OC) and fine particles in the southeastern United States were investigated using molecular marker‐based chemical mass balance modeling (CMB‐MM) and carbon isotope analysis. Nine primary emission sources were resolved with wood combustion (average 1.73 μg m−3, 23 ± 14% of measured OC) being the most dominant contributor to OC, followed by gasoline engine exhaust (0.45 μg m−3, 6.1 ± 6.2% of OC), diesel engine exhaust (0.43 μg m−3, 4.8 ± 4.1% of OC), and meat cooking (0.30 μg m−3, 4.1 ± 2.6% of OC). Measurable contributions from vegetative detritus, cigarette smoke, road dust, and natural gas exhaust were found. The impact of coke facilities was estimated for the first time in Birmingham, Alabama, and contributed 0.52 μg m−3 on average to fine OC. The unexplained OC accounted for 54 ± 26% of measured OC, possibly because of contributions from secondary OC, other unidentified primary sources and the possible positive artifact of OC. The urban excess of OC from diesel exhaust, gasoline exhaust and meat cooking can be seen from the results of the urban‐rural pair in Alabama. Detailed chemical analysis revealed the wood burning episode at the rural site and an episode of secondary formation in the study region. The 14C analysis, a tool to study the relative contributions of contemporary and fossil carbon contents of fine particles, agreed well with the CMB‐MM analysis. Both reflected a higher fossil fraction of carbon at urban sites especially in Birmingham, Alabama.
Heteroclinic bifurcations and chaotic transport in the two-harmonic standard map
Authors: Lomelí Héctor E. , Calleja Renato
Published: May 2006

We study a two-parameter family of standard maps: the so-called two-harmonic family. In particular, we study the areas of lobes formed by the stable and unstable manifolds. Variational methods are used to find heteroclinic orbits and their action. A specific pair of heteroclinic orbits is used to define a difference in action function and to study bifurcations in the stable and unstable manifolds. Using this idea, two phenomena are studied: the change of orientation of lobes and tangential intersections of stable and unstable manifolds.
Fluorescence and metastability of N2O2+: Theory and experiment
Authors: Taylor S. , Eland J. H. D. , Hochlaf M.
Published: May 2006

State-selective mass spectrometry has revealed one conclusive and another probable metastable state of the N2O2+ dication, assigned respectively as 1Π3 at 38.5eV and 2Π3 at 42.5eV. Photon coincidence experiments confirm that dissociation of 1Π3 is preceded by a fluorescent transition to XΣ−3 and also indicate that an identical mechanism occurs for 2Π3. Highly correlated MRCI calculations are performed at a range of N2O2+ geometries, from which both N–N and N–O bond stretching curves are generated. Substantial barriers along both coordinates are observed for 1Π3 and 2Π3, although the increasing density of states at higher energy may allow spin-orbit or vibronic predissociation for 2Π3. Fragment emissions derived from N2O+ and N2O2+ are analyzed with the aid of glass filters, from which NO (XΠ2←AΣ+2) and vibrationally excited N2+ (XΣg+2←BΣu+2) transitions are deduced.
Rate processes with dynamical disorder: A direct variational approach
Authors: Debnath Ananya , Chakrabarti Rajarshi , Sebastian K. L.
Published: May 2006

Using path integral approach, we develop variational approximations to the calculation of survival probability for rate processes with dynamical disorder. We derive both upper and lower bounds to the survival probability using Jensen’s inequality. The inequalities involve the use of a trial action for which the path integrals can be evaluated exactly. Any parameter in the trial action can be varied to optimize the bounds. We have also derived a lower bound to the rate of the process. As a simple illustration, we apply the method to the problem of a particle undergoing Brownian motion in a harmonic potential well, in the presence of a delta function sink, for which one can calculate the exact survival probability numerically. The calculation confirms the two inequalities. The method should be very useful in similar but more complex problems where even numerical solution is not possible.
First-principles study of low compressibility osmium borides
Authors: Gou Huiyang , Hou Li , Zhang Jingwu , Li Hui , Sun Guifang , Gao Faming
Published: May 2006

Using first-principles total energy calculations we investigate the structural, elastic, and electronic properties of OsB2 and OsB, respectively. The calculated equilibrium structural parameters of OsB2 are in agreement with the available experimental results. The calculations indicate that OsB in tungsten carbide is more energetically stable under the ambient condition than the metastable cesium chloride phase of OsB. Results of bulk modulus show that they are potential low compressible materials. The hardness of OsB2 is estimated by employing a semiempirical theory. The results indicate that OsB2 is an ultraincompressible material, but not a superhard material. The method designing superhard materials is different from one creating ultraincompressible materials.
Calibrating the Fine Fuel Moisture Code for grass ignition potential in Sumatra, Indonesia
Authors: de Groot William J. , Wardati  , Wang Yonghe
Published: May 2006

Grass moisture and ignition studies were conducted in central Sumatra, Indonesia, to develop an indicator of grass ignition potential using the Fine Fuel Moisture Code (FFMC) of the Canadian Forest Fire Weather Index System. Moisture content of live and dead grass was measured at three sites every 6 days over an 8-month period. Grass curing was highly variable but averaged 37–39% and often exceeded 50% from April to mid-August. Grass fuel loads averaged 420–722 g/m2. There was a highly significant decrease in dead grass moisture content with increasing FFMC, decreasing grass height, and decreasing total grass biomass. The FFMC was the most influential factor, explaining 54–61% of the dead grass moisture content variation. Ignition tests were applied to live and dead grass samples with specific moisture contents. The ignition threshold of dead and live grass occurred at 35.4% and 27.8% moisture content, respectively. The dead grass ignition threshold corresponded to FFMC values of 81.0–83.3 at the three study sites. Of historical hot spots in South-east Asia, 86% occurred when the FFMC was ≥78, representing the lower 95% confidence interval of the dead grass ignition threshold. The FFMC was calibrated using experimental results for fire management applications.
Vegetation and topographical correlates of fire severity from two fires in the Klamath-Siskiyou region of Oregon and California
Authors: Alexander John D. , Seavy Nathaniel E. , Ralph C. John , Hogoboom Bill
Published: May 2006

We used vegetation data collected in areas before they were burned by the 2500 ha Quartz fire in southern Oregon and the 50 600 ha Big Bar complex in northern California to evaluate the ability of vegetation and topographic characteristics to predict patterns of fire severity. Fire severity was characterized as high, moderate, or low based on crown scorch and consumption, and changes in soil structure. In both fires, vegetation plots with southern aspects were more likely to burn with high severity than plots with eastern, northern, or western aspects. This was the only consistent predictor across both fires. In the Quartz fire, we found that plots at higher elevations and with larger diameter trees were more likely to burn with low or moderate severity. These correlations may have been influenced in part by the effects of unmeasured weather conditions. We found few strong correlates in the Big Bar complex, owing in part to the fact that most (75%) of our plots were in the low-severity category, providing relatively little variation. These results, in combination with previous studies of fire severity in the Klamath-Siskiyou region, suggest that areas with southern aspects tend to burn with greater severity than those of other aspects, areas with large trees burn less severely than those with smaller trees, and that correlates of fire severity vary extensively among fires.
Predicting and mitigating weed invasions to restore natural post-fire succession in Mesa Verde National Park, Colorado, USA
Authors: Floyd M. Lisa , Hanna David , Romme William H. , Crews Timothy E.
Published: May 2006

Six large wildfires have burned in Mesa Verde National Park during the last 15 years, and extensive portions of burns were invaded by non-native plant species. The most threatening weed species include Carduus nutans, Cirsium arvense, and Bromus tectorum, and if untreated, they persist at least 13 years. We investigated patterns of weed distribution to identify plant communities most vulnerable to post-fire weed invasion and created a spatially explicit model to predict the most vulnerable sites. At the scale of the entire park, mature piñon–juniper woodlands growing on two soil series were most vulnerable to post-fire weed invasion; mountain shrublands were the least vulnerable. At a finer scale, greater richness of native species was correlated with greater numbers of non-native species, indicating that habitats with high native biodiversity are at the greatest risk of weed invasion. In unburned areas, weed density increased with greater soil nitrogen and phosphorus, and lower salinity. In burned areas weed density correlated with soil nitrogen status and textural class. We also evaluated the effectiveness of a variety of weed mitigation methods; aerial seeding of targeted high-risk areas with native grasses was the most effective treatment tested. We recommend a conservative mitigation plan using natives grass seed on only the most invasible sites.
Dry-season use of space, habitats and shelters by the short-eared rock-wallaby (Petrogale brachyotis) in the monsoon tropics
Authors: Telfer Wendy R. , Griffiths Anthony D.
Published: May 2006

It is widely recognised that the use of fixed diurnal shelters by rock-wallabies greatly affects their ecology. However, the details of how shelters and surrounding habitats are used, and how similar these characteristics are across rock-wallaby species, remain scarcely understood. The dry season home range, and use of habitats and den sites, of the short-eared rock wallaby (Petrogale brachyotis) were examined at Litchfield National Park, Northern Territory, Australia. We radio-tracked 10 individuals on foot to locate diurnal shelters, and with fixed towers to determine their nocturnal positions. P. brachyotis used a range of rock piles and outcrops for dens, and showed a strong preference for rocky habitats and adjacent woodland. On average, animals used four dens within outcrops, as well as more exposed resting sites. Individual rock-wallabies sometimes shared dens, but there appeared to be male–male intolerance of simultaneous use of dens. Mean home range in the dry season was 18.3 ha, and there was no significant difference in home-range area between sexes. Use of space by P. brachyotis was very similar to that reported for another tropical rock-wallaby species, P. assimilis, and many behavioural traits were also similar to those found in other species of Petrogale.
The diet of powerful owls (Ninox strenua) and prey availability in a continuum of habitats from disturbed urban fringe to protected forest environments in south-eastern Australia
Authors: Cooke R. , Wallis R. , Hogan F. , White J. , Webster A.
Published: May 2006

This study investigates the diet of six breeding pairs of powerful owls in the Yarra Valley Corridor in Victoria, Australia, and compares prey consumption with prey availability. The six sites represent a continuum of habitats, ranging from urban Melbourne, through the urban fringe interface to a more forested landscape. We found that powerful owls in the Yarra Valley Corridor are reliant almost exclusively on arboreal marsupial prey as their preferred diet, with 99% of their overall diet comprising four arboreal marsupial species. These four species (the common ringtail possum, common brushtail possum, sugar glider and greater glider) were also the most abundant species observed while spotlighting; however, their abundance varied along the continuum. There was a strong positive relationship with the presence of these species in the diet and their site-specific availability, indicating that the powerful owl is a generalist hunter, preying on the most available prey at a given site and in a given season. This study suggests that food resources are high in these disturbed urban fringe sites and it is unlikely that food availability in urban environments will limit the potential survival of urban powerful owls.
Polymerization of hyperphosphorylated tau into filaments eliminates its inhibitory activity
Authors: Alonso Alejandra del C. , Li Bin , Grundke-Iqbal Inge , Iqbal Khalid
Published: May 2006

Accumulation of abnormally hyperphosphorylated tau (P-tau) in the form of tangles of paired helical filaments and/or straight filaments is one of the hallmarks of Alzheimer's disease (AD) and other tauopathies. P-tau is also found unpolymerized in AD. Although the cognitive decline is known to correlate with the degree of neurofibrillary pathology, whether the formation of filaments or the preceding abnormal hyperphosphorylation of tau is the inhibitory entity that leads to neurodegeneration has been elusive. We have previously shown that cytosolic abnormaly hyperphosphorylated tau in AD brain (AD P-tau) sequesters normal tau (N-tau), microtubule-associated protein (MAP) 1, and MAP2, which results in the inhibition of microtubule assembly and disruption of microtubules. Here, we show that polymerization of AD P-tau into filaments inhibits its ability to bind N-tau and as well as the ability to inhibit the assembly of tubulin into microtubules
in vitro
and in the regenerating microtubule system from cultured cells. Like AD P-tau, the
in vitro
abnormally hyperphosphorylated recombinant brain N-tau binds N-tau and loses this binding activity on polymerization into filaments. Dissociation of the hyperphosphorylated N-tau filaments by ultrasonication restores its ability to bind N-tau. These findings suggest that the nonfibrillized P-tau is most likely the responsible entity for the disruption of microtubules in neurons in AD. The efforts in finding a therapeutic intervention for tau-induced neurodegeneration need to be directed either to prevent the abnormal hyperphosphorylation of this protein or to neutralize its binding to normal MAPs, rather than to prevent its aggregation into filaments.
Limbic hyperactivation during processing of neutral facial expressions in children with bipolar disorder
Authors: Rich Brendan A. , Vinton Deborah T. , Roberson-Nay Roxann , Hommer Rebecca E. , Berghorst Lisa H. , McClure Erin B. , Fromm Stephen J. , Pine Daniel S. , Leibenluft Ellen
Published: May 2006

Reflecting a paradigm shift in clinical neuroscience, many chronic psychiatric illnesses are now hypothesized to result from perturbed neural development. However, most work in this area focuses on schizophrenia. Here, we extend this paradigm to pediatric bipolar disorder (BD), thus demonstrating traction in the developmental psychobiology perspective. To study amygdala dysfunction, we examined neural mechanisms mediating face processing in 22 youths (mean age 14.21 ± 3.11 yr) with BD and 21 controls of comparable age, gender, and IQ. Event-related functional MRI compared neural activation when attention was directed to emotional aspects of faces (hostility, subjects’ fearfulness) vs. nonemotional aspects (nose width). Compared with controls, patients perceived greater hostility in neutral faces and reported more fear when viewing them. Also, compared with controls, patients had greater activation in the left amygdala, accumbens, putamen, and ventral prefrontal cortex when rating face hostility, and greater activation in the left amygdala and bilateral accumbens when rating their fear of the face. There were no between-group behavioral or neural differences in the nonemotional conditions. Results implicate deficient emotion–attention interactions in the pathophysiology of BD in youth and suggest that developmental psychobiology approaches to chronic mental illness have broad applicability.
PROBABILITY DISTRIBUTIONS RELATED TO THE LAW OF THE ITERATED LOGARITHM
Authors: Robbins H. , Siegmund D.
Published: May 2006

Let
W
(
t
) denote a standard Wiener process for 0 ≤
t
< ∞. We compute the probability that
W
(
t
) ≥
t
½
A
(
t
) for some
t
≥ 1 (or for some
t
≥ 0) for a certain class of functions
A
(
t
), including functions which are ∼ (2 log log
t
)
½
as
t
→ ∞. We also give an invariance principle which states that this probability is the limit as
m
→ ∞ of the probability that

s
n

≥
n
½
A
(
n/m
) for some
n
≥
m
(or for some
n
≥ 1), where

s
n

is the sum of
n
independent and identically distributed random variables with mean 0 and variance 1.
ELECTRON MICROSCOPY OF THE CIRCULAR KINETOPLASTIC DNA FROM TRYPANOSOMA CRUZI: OCCURRENCE OF CATENATED FORMS
Authors: Riou Guy , Delain Etienne
Published: May 2006

Circular kinetoplastic DNA was fractionated from
Trypanosoma cruzi
DNA by Hg-Cs
2
SO
4
gradient. Covalantly closed circular DNA was isolated by buoyant density centrifugation in ethidium bromide CsCl density gradients. Electron microscope studies have shown that kinetoplastic DNA molecules are in the form of open and closed circles of contour length 0.45 μ, the smallest known microbial DNA. DNA molecules are also in the form of catenanes consisting of two or more topologically interlocked circular units of the monomer size 0.45 μ. Associations of numerous circles have also been described and confirmed by band sedimentation. Long linear DNA molecules were also seen, their size ranging between 2 and 12 μ. These molecules are free or are attached to associations of circles.
DEOXYRIBONUCLEASE IV: A NEW EXONUCLEASE FROM MAMMALIAN TISSUES
Authors: Lindahl Tomas , Gally Joseph A. , Edelman Gerald M.
Published: May 2006

An exonuclease which specifically degrades double-standard DNA has been isolated from rabbit tissues. The enzyme has an approximate molecular weight of 42,000, requires a divalent metal ion as cofactor, and attacks DNA at the 5′-terminal ends, thereby liberating 5′-mononucleotides. It degrades several synthetic polydeoxynucleotides of single repeating base sequences more rapidly than DNA from natural sources. The specificity of this mammalian enzyme resembles that of several microbial enzymes (phage λ exonuclease and DNA polymerase) which appear to be required for repair and recombination of DNA.
THE RADICAL OF A JORDAN ALGEBRA
Authors: McCrimmon Kevin
Published: May 2006

In this paper we define a Jacobson radical for Jordan algebras analogous to that for associative algebras and show that it enjoys many of the properties of the associative radical. We then relate the corresponding notion of “semisimplicity” to the previously defined notion of “nondegeneracy” (Jacobson, N., these
Proceedings
,
55,
243-251 (1966)).
ACTIVE TRANSPORT OF MAGNESIUM IN
Escherichia coli
Authors: Silver Simon
Published: May 2006

Magnesium-28 is accumulated by cells of
Escherichia coli
by a process that is temperature-dependent and inhibited by dinitrophenol and cyanide. The rate of uptake of magnesium is concentration-dependent, with a “

K
m

” of about 5 × 10
-4
M
in tryptone broth. There is evidence for cellular control over this rate. The magnesium accumulation system is specific, since neither potassium nor calcium (nor apparently manganese) competes with magnesium for cellular uptake. The magnesium that is accumulated by the cells can be released by treatment with toluene and partially exchanges with excess exogenous magnesium.
INTERFERENCE OF MOONLIGHT WITH THE PHOTOPERIODIC MEASUREMENT OF TIME BY PLANTS, AND THEIR ADAPTIVE REACTION
Authors: Bünning Erwin , Moser Ilse
Published: May 2006

Threshold values of photoperiodic time-measurements correspond approximately to moonlight intensities. Experiments with
Glycine
and
Euglena
reveal that this is also the threshold value for synchronization of the circadian cycle. Saturation of this reaction is reached with 10 lx in 12:12 hr light-dark cycles. Thus, moonlight might disturb time measurement.

In
Glycine, Arachis
, and
Trifolium
the intensity of the light coming from the moon to the upper surface of the leaf is reduced by circadian leaf movement to values between 5 and 20 per cent (or even less than 5 per cent) of full-moon light intensity. Such a reduction eliminates the disturbing effects of moonlight. This finding indicates that leaf movements have an adaptive value of the kind that Darwin sought to identify. It also indicates that the behavior of the upper leaf epidermis as a “sense organ for light”
13
has an adaptive value.

In the short-day plants
Perilla ocymoides
and
Chenopodium amaranticolor
, a specific photoperiodic phenomenon was found that counteracts the disturbing effect of moonlight. Here light intensities similar to those of moonlight, introduced during the night, promote flowering instead of inhibiting it.
LOCATION OF SINGLE-STRAND INTERRUPTIONS IN THE DNA OF BACTERIOPHAGE T5
+
Authors: Bujard Hermann
Published: May 2006

The positions of three single-strand interruptions in the DNA of phage T5
+
have been located by electron microscopy. All three interruptions were found in the same strand. Uneven base composition along the molecule is indicated by the preferential melting of certain regions. The data suggest a model according to which (1) the first-step-transfer DNA section is separated by a single-strand interruption from the rest of the phage genome, (2) the phage carries only one such section and therefore transfers the asymmetrical DNA molecule always in the same direction into the host cell, and (3) single-strand interruptions are points of preferred breakage.
SEPARATION OF MICROBIAL DEOXYRIBONUCLEIC ACIDS INTO COMPLEMENTARY STRANDS
Authors: Rudner Rivka , Karkas John D. , Chargaff Erwin
Published: May 2006

DNA preparations from seven bacterial species and from the
E. coli
phage T4 can, after denaturation with alkali, be separated chromatographically into two distinct components (L and H) through intermittent gradient elution from methylated albumin kieselguhr columns. The direct chemical analysis of the L and H fractions isolated from DNA specimens of the AT type shows them to exhibit a high degree of complementarity; but despite a bias in the distribution of purines and pyrimidines, either fraction contains equimolar quantities of 6-amino and of 6-keto nucleotides. In the L and H components derived from DNA of the equimolar and GC types, the distribution bias appears limited to guanine and cytosine. It is suggested that the L and H fractions represent the complementary DNA strands.
CONGENITAL METHYLMALONIC ACIDEMIA: ENZYMATIC EVIDENCE FOR TWO FORMS OF THE DISEASE
Authors: Morrow Grant , Barness Lewis A. , Cardinale George J. , Abeles Robert H. , Flaks Joel G.
Published: May 2006

Methylmalonic acidemia is an inherited metabolic disorder thus far found in children and characterized by the excessive excretion of methylmalonate in the urine. Typically these children exhibit vomiting, lethargy, ketoacidosis, and failure to grow. Many of the patients are mentally retarded and die early in life. Two variants of this disease are known. In one, the administration of vitamin B
12
will reverse or prevent these clinical findings, whereas in a second variant vitamin B
12
therapy is of no value.

This paper presents the first enzymatic evidence (obtained with cell-free liver extracts) that bears on two important aspects of the disease. It has been found that methylmalonylCoA carbonylmutase activity is essentially absent in the livers of patients suffering from one variant (vitamin B
12
-unresponsive) of the disease. Secondly, it has been found that the livers of patients with the second variant (vitamin B
12
-responsive) of the disease show normal enzymatic behavior in the presence of the coenzyme form of vitamin B
12
, but are identical to the vitamin B
12
-unresponsive variant in the absence of the added coenzyme. Thus the enzyme studies fully support the clinical observations that two types of this disease exist.