bluuebunny/crossref_metadata_2025 huggingface dataset:
Proteomic response of Schizosaccharomyces pombe to static and oscillating extremely low‐frequency electromagnetic fields
Authors: Sinclair John , Weeks Mark , Butt Amna , Worthington Jessica L. , Akpan Akunna , Jones Nic , Waterfield Mike , Allanand Donald , Timms John F.
Published: August 2006

There is considerable public concern regarding the health effects of exposure to low‐frequency electromagnetic fields. In addition, the association between exposure and disease incidence or the possible biological effects of exposure are unclear. Using 2D‐DIGE and MS in a blind study, we have investigated the effects of static and oscillating extremely low‐frequency electromagnetic fields (ELF EMFs) on the proteomes of wild type Schizosaccharomyces pombe and a Sty1p deletion mutant which displays increased sensitivity to a variety of cellular stresses. Whilst this study identifies a number of protein isoforms that display significant differential expression across experimental conditions, there was no correlation between their patterns of expression and the ELF EMF exposure regimen. We conclude that there are no significant effects of either static or oscillating EMF on the yeast proteome at the sensitivity afforded by 2D‐DIGE. We hypothesise that the proteins identified must be sensitive to subtle changes in culture and/or handling conditions, and that the identification of these proteins in other proteomic studies should be treated with some caution when the results of such studies are interpreted in a biological context.
Job loss and reemployment after a cancer diagnosis in Koreans—a prospective cohort study
Authors: Choi Kui Son , Kim Eun‐Jung , Lim Jin‐Hwa , Kim Sung‐Gyeong , Lim Min Kyung , Park Jae‐Gahb , Park Eun‐Cheol
Published: August 2006

Patients undergoing treatment for cancer have reported a variety of work‐related problems. The aim of this study was to investigate the impact of a cancer diagnosis on employment status, and to identify relevant associated factors. This prospective cohort study was conducted at the National Cancer Center in Korea. Male patients newly diagnosed with stomach, liver, or colorectal cancers were recruited. Patients were interviewed and asked to complete an employment questionnaire every 3 months for 24 months. Clinical, sociodemographic and work‐related factors were assessed. There were 305 male patients who had a primary diagnosis of cancer and underwent appropriate treatment. Of the 305 male patients who were employed at the time of diagnosis, 53% lost their job, and of these 23% later reemployed. In a multivariate Cox regression analysis, job loss was significantly associated with years of education, job characteristics and disease stage. Reemployment was significantly associated with disease stage and cancer site. Change of employment was common among cancer patients in Korea. With an understanding of the factors involved, it should be possible to reduce unnecessary work cessation, and increase the rate of employment of cancer survivors. Copyright © 2006 John Wiley & Sons, Ltd.
Simple fast and adaptive lossless image compression algorithm
Authors: Starosolski Roman
Published: August 2006

In this paper we present a new lossless image compression algorithm. To achieve the high compression speed we use a linear prediction, modified Golomb–Rice code family, and a very fast prediction error modeling method. We compare the algorithm experimentally with others for medical and natural continuous tone grayscale images of depths of up to 16 bits. Its results are especially good for large images, for natural images of high bit depths, and for noisy images. The average compression speed on Intel Xeon 3.06 GHz CPU is 47 MB/s. For large images the speed is over 60 MB/s, i.e. the algorithm needs less than 50 CPU cycles per byte of image. Copyright © 2006 John Wiley & Sons, Ltd.
Escalating dose pretreatment induces pharmacodynamic and not pharmacokinetic tolerance to a subsequent high‐dose methamphetamine binge
Authors: O'Neil Meghan L. , Kuczenski Ronald , Segal David S. , Cho Arthur K. , Lacan Goran , Melega William P.
Published: August 2006

A major feature of human methamphetamine (METH) abuse is the gradual dose escalation that precedes high‐dose exposure. The period of escalating doses (EDs) is likely associated with development of tolerance to aspects of METH's pharmacologic and toxic effects but the relative contributions of pharmacokinetic and pharmacodynamic factors have not been well defined. In our prior studies in rats, we showed that pretreatment with an ED‐METH regimen (0.1–4.0 mg/kg over 14 days) attenuated the toxicity of a subsequently administered high‐dose METH binge (4 × 6 mg/kg at 2 h interval) that itself produced behavioral stereotypy, increases in core temperature, and decreases in DA system phenotypic markers in caudate‐putamen (CP). Using those ED‐METH and binge protocols in the present studies, pharmacokinetic and pharmacodynamic parameters that may have contributed to the apparent neuroprotection afforded by ED‐METH were assessed. The ED‐METH regimen itself reduced [3H]WIN35,428 (WIN) binding to the dopamine transporter (DAT) by 15% in CP, but did not affect DA content. During the METH binge, ED‐METH pretreated animals showed attenuated increases in core temperature while concurrent microdialysis studies in CP showed a reduced DA response despite unaltered extracellular levels of METH. At 1 h after the binge, concentrations of METH and its metabolite amphetamine in brain and plasma were unaffected by the ED‐METH. The results show that ED‐METH pretreatment produces reductions in DAT binding and the DA response during a subsequent METH binge by altering pharmacodynamic and not pharmacokinetic parameters. Synapse 60:465–473, 2006. © 2006 Wiley‐Liss, Inc.
Tank monitoring: a pAMN case study
Authors: Schneider Steve , Hoang Thai Son , Robinson Ken , Treharne Helen
Published: August 2006

The introduction of probabilistic behaviour into the B-method is a recent development. In addition to allowing probabilistic behaviour to be modelled, the relationship between expected values of the machine state can be expressed and verified. This paper explores the application of probabilistic B to a simple case study: tracking the volume of liquid held in a tank by measuring the flow of liquid into it. The flow can change as time progresses, and sensors are used to measure the flow with some degree of accuracy and reliability, modelled as non-deterministic and probabilistic behaviour respectively. At the specification level, the analysis is concerned with the
expectation
clause in the probabilistic B machine and its consistency with machine operations. At the refinement level, refinement and equivalence laws on probabilistic GSL are used to establish that a particular design of sensors delivers the required level of reliability.
Mortality in a cohort of chronically fatigued patients
Authors: SMITH WAYNE R. , NOONAN CAROLYN , BUCHWALD DEDRA
Published: August 2006

Background. Comprehensive studies of mortality among patients with chronic fatigue (CF) and chronic fatigue syndrome (CFS) have not been published, but several sources suggest that CFS is associated with an elevated risk for suicide.

Method. Data on 1201 chronically fatigued patients followed in a university-affiliated tertiary-care clinic for up to 14 years were submitted to the Center for Disease Control and Prevention (CDC) National Death Index (NDI) to evaluate all-cause and suicide-caused death rates against standardized mortality rates (SMRs). We used Life Table Analysis to examine the influence of sex and diagnoses of CFS and depression.

Results. All-cause mortality in chronically fatigued patients was no higher than expected, but suicide-caused death rates were more than eight times higher than in the US general population. The significant elevation in the SMR of suicide was restricted to those who did not meet criteria for CFS [SMRCF=14·2, 95% confidence interval (CI) 5·7–29·3 versus SMRCFS=3·6, 95% CI 0·4–12·9]. Among chronically fatigued patients who did not meet CFS criteria, those with a lifetime history of major depression (MD) had higher suicide-caused death rates than among their non-depressed counterparts (SMRMD=19·1, 95% CI 7·0–41·5 versus SMRNMD=5·6, 95% CI 0·1–31·4), although the difference was not significant.

Conclusions. CFS does not appear to be associated with increased all-cause mortality or suicide rates. Clinicians, however, should carefully evaluate patients with CF for depression and suicidality.
IN THIS ISSUE
Authors: MORGAN CRAIG
Published: August 2006

This issue contains a review on child-onset bipolar disorder. Other sets of papers examine various aspects of bipolar disorder, depression and suicide, anxiety, and chronic fatigue, and four individual papers examine a variety of topics.
Dimensional representations of DSM-IV Cluster A personality disorders in a population-based sample of Norwegian twins: a multivariate study
Authors: KENDLER KENNETH S. , CZAJKOWSKI NIKOLAI , TAMBS KRISTIAN , TORGERSEN SVENN , AGGEN STEVEN H. , C. NEALE MICHAEL , REICHBORN-KJENNERUD TED
Published: August 2006

Background. The ‘odd’ or ‘Cluster A’ personality disorders (PDs) – paranoid, schizoid and schizotypal PDs – were created in DSM-III with little empirical foundation. We have examined the relationship between the genetic and environmental risk factors for dimensional representations of these three personality disorders.

Method. These personality disorders were assessed using the Structured Interview for DSM-IV Personality (SIDP-IV) in 1386 young adult twin pairs from the Norwegian Institute of Public Health Twin Panel. Using Mx, a single-factor independent pathway twin model was fitted to the number of endorsed criteria for the three disorders.

Results. The best-fit model included genetic and unique environmental common factors and genetic and unique environmental effects specific to each personality disorder. Total heritability was modest for these personality disorders and ranged from 21% to 28%. Loadings on the common genetic and unique environmental factors were substantially higher for schizotypal than for paranoid or schizoid PD. The proportion of genetic liability shared with all Cluster A disorders was estimated at 100, 43 and 26% respectively for schizotypal, paranoid and schizoid PDs.

Conclusion. In support of the validity of the Cluster A construct, dimensional representations of schizotypal, paranoid and schizoid PD are all modestly heritable and share a portion of their genetic and environmental risk factors. No evidence was found for shared environmental or sex effects for these PDs. Schizotypal PD most closely reflects the genetic and environmental liability common to all three Cluster A disorders. These results should be interpreted in the context of the limited power of this sample.
Mechanism of peptide bond formation on the ribosome
Authors: Rodnina Marina V. , Beringer Malte , Wintermeyer Wolfgang
Published: August 2006

1. The ribosome 204

2. Peptide bond formation is catalyzed by RNA 205

3. Characteristics of the uncatalyzed reaction 207

4. Potential catalytic strategies of the ribosome 207

5. Experimental systems 208

6. Substrate binding in the PT center 210

7. Induced fit in the active site 211

8. pH dependence of peptide bond formation 212

9. Reaction with full-length aa-tRNA 214

10. Role of active-site residues 215

11. pH-dependent structural changes of the active site 216

12. Entropic catalysis 217

13. Role of 2′-OH of A76 in P-site tRNA 218

14. Catalysis by proton shuttling 219

15. Plasticity of the active site 220

16. Conclusions 221

17. Acknowledgments 222

18. References 222

Peptide bond formation is the fundamental reaction of ribosomal protein synthesis. The ribosome's active site – the peptidyl transferase center – is composed of rRNA, and thus the ribosome is the largest known RNA catalyst. The ribosome accelerates peptide bond formation by 107-fold relative to the uncatalyzed reaction. Recent progress of structural, biochemical and computational approaches has provided a fairly detailed picture of the catalytic mechanisms employed by the ribosome. Energetically, catalysis is entirely entropic, indicating an important role of solvent reorganization, substrate positioning, and/or orientation of the reacting groups within the active site. The ribosome provides a pre-organized network of electrostatic interactions that stabilize the transition state and facilitate proton shuttling involving ribose hydroxyl groups of tRNA. The catalytic mechanism employed by the ribosome suggests how ancient RNA-world enzymes may have functioned.
Experimental results for output feedback adaptive robot control
Authors: Daly John M. , Schwartz Howard M.
Published: August 2006

This paper examines three methods of adaptive output feedback control for robotic manipulators. Implementing output feedback control allows use of only the position information, which can be measured quite accurately. Velocity and acceleration measurements can get corrupted by noise. A method proposed by K. W. Lee and H. K. Khalil [Adaptive output feedback control of robot manipulators using high-gain observer, Int. J. Control, 6, 869–886 (1997)] using a high-gain observer, one proposed by J. J. Craig, P. Hsu and S. S. Sastry [Adaptive control of mechanical manipulators, Int. J. Robot. Res., 6(2), 16–27 (1987)] with the addition of a linear observer that we propose, and a method proposed by R. Gourdeau and H. M. Schwartz [Adaptive control of robotic manipulators: Experimental results, Proceedings of the 1991 IEEE International Conference on Robotics and Automation (Apr. 1991) pp. 8–15] using an Extended Kalman Filter are examined. The methods are implemented in simulation and experimentally on a direct-drive robot. The performance of each of the algorithms is compared.
Factors shaping implementation of protected area management decisions: a case study of the Zakynthos National Marine Park
Authors: TOGRIDOU ANATOLI , HOVARDAS TASOS , PANTIS JOHN D.
Published: August 2006

Institutional and non-institutional factors for the success of protected area (PA) governance have repeatedly been identified, but their relative weight has not been evaluated. To investigate the implementation of PA management in Zakynthos (Greece), meeting minutes of the local Park Authority for its first four years of operation were reviewed and statistically analysed. The Park Authority's autonomy and management complexity were indicated and with reference to governance, members of the local Park Authority belonged to the ‘inner-circle’ of decision-making and the Ministry of Environment formed the ‘environment’, since administrative issues had to be approved by the latter. Implementation of actions referring to administrative issues was less likely than implementation of environmental, social and economic arrangements, where the Park Authority had a higher degree of autonomy. The implementation of arrangements for promoting administrative stability and viability was highly dependent on external actions (annual government funding and approval of by-law governance and implementation). The more sophisticated and complex the governance system became, the more likely it was that Park Authority encountered difficulty when trying to make choices and changes. The methodology proved effective in revealing the management behaviour of the Park Authority, as well as indicating institutional and non-institutional issues that most significantly affected the harnessing of resources and the degree of action implementation; this could offer crucial feedback to managers and governmental representatives on the factors responsible for the success or failure of PA management.
Potential microbiological contamination of effluents in poultry and swine abattoirs
Authors: BARROS L. S. S. , AMARAL L. A. , LORENZON C. S. , JUNIOR J. L. , NETO J. G. MACHADO
Published: August 2006

Health risks in the effluents of seven swine abattoirs and of seven poultry abattoirs were evaluated with regard to environment degradation and to dissemination of pathogenic microorganisms during the rainy and dry seasons. Supply-water samples from affluents and effluents of the treatment systems at different sites within the abattoir processing system were analysed. Similarly, water samples from the three recipient sites (emission point, 100 m upstream, 100 m downstream) were also analysed. Temperature, free residual chlorine (FRC), total coliform bacteria, Escherichia coli, enterococci, identification and serotyping of salmonellae were assessed. Scalding is the most significant stage in the slaughtering chain (P<0·05) when temperature is taken into account. Temperatures at effluents and at the sampled sites in the water bodies accorded to state and federal legislation standards. Supply waters did not meet the standards for FRC and microbial count standards according to the Ministry of Health and within limits imposed by the Industrial and Sanitary Inspection Regulations for Animal Products. Feather plucking and evisceration in poultry slaughter and the cleansing of carcasses and facilities in poultry and swine slaughtering had the highest contamination impact. The three loci at the water bodies were above the microbiological standards for classes II and III sites, in conformity with Law 8468 of the state of São Paulo, Brazil and Conama. Salmonella was found at several sites during slaughter, at both types of abattoirs, including in the effluent treatment system. This showed that these sites were the dissemination sources of the microorganism.
Possible ecology and epidemiology of medically important mosquito-borne arboviruses in Great Britain
Authors: MEDLOCK J. M. , SNOW K. R. , LEACH S.
Published: August 2006

Nine different arboviruses are known to be transmitted by, or associated with, mosquitoes in Europe, and several (West Nile, Sindbis and Tahyna viruses) are reported to cause outbreaks of human disease. Although there have been no reported human cases in Great Britain (GB), there have been no published in-depth serological surveys for evidence of human infection. This paper investigates the ecological and entomological factors that could influence or restrict transmission of these viruses in GB, suggesting that in addition to West Nile virus, Sindbis and Tahyna viruses could exist in enzootic cycles, and that certain ecological factors could facilitate transmission to humans. However, the level of transmission is likely to be lower than in endemic foci elsewhere in Europe due to key ecological differences related to spatial and temporal dynamics of putative mosquito vectors and presence of key reservoir hosts. Knowledge of the potential GB-specific disease ecology can aid assessments of risk from mosquito-borne arboviruses.
The Lyme vaccine: a cautionary tale
Authors: NIGROVIC L. E. , THOMPSON K. M.
Published: August 2006

People living in endemic areas acquire Lyme disease from the bite of an infected tick. This infection, when diagnosed and treated early in its course, usually responds well to antibiotic therapy. A minority of patients develops more serious disease, particularly after a delay in diagnosis or therapy, and sometimes chronic neurological, cardiac, or rheumatological manifestations. In 1998, the FDA approved a new recombinant Lyme vaccine, LYMErix™, which reduced new infections in vaccinated adults by nearly 80%. Just 3 years later, the manufacturer voluntarily withdrew its product from the market amidst media coverage, fears of vaccine side-effects, and declining sales. This paper reviews these events in detail and focuses on the public communication of risks and benefits of the Lyme vaccine and important lessons learned.
On an extended clarifier-thickener model with singular source and sink terms
Authors: BÜRGER R. , GARCIA A. , KARLSEN K. H. , TOWERS J. D.
Published: August 2006

A one-dimensional model of clarifier-thickener units in engineering applications can be expressed as a conservation law with a flux that is discontinuous with respect to the spatial variable. This model also includes a singular feed source. In this paper, the clarifier-thickener model studied in a previous paper (Numer. Math.97 (2004) 25–65) is extended by a singular sink through which material is extracted from the unit. A difficulty is that in contrast to the singular source, the sink term cannot be incorporated into the flux function; rather, the sink is represented by a new non-conservative transport term. To focus on the new analytical difficulties arising due to this non-conservative term, a reduced problem is formulated, which contains the new sink term of the extended clarifier-thickener model, but not the source term and flux discontinuities. The paper is concerned with numerical methods for both models (extended and reduced) and with the well-posedness analysis for the reduced problem. For the reduced problem, a definition of entropy solutions, based on Kružkov-type entropy functions and fluxes, is provided. Jump conditions are derived and uniqueness of the entropy solution is shown. Existence of an entropy solution is shown by proving convergence of a monotone difference scheme. Two variants of the numerical scheme are introduced. Numerical examples illustrate that all three variants converge to the entropy solution, but introduce different amounts of numerical diffusion.
Terrestrial models for extraterrestrial life: methanogens and halophiles at Martian temperatures
Authors: Reid I.N. , Sparks W.B. , Lubow S. , McGrath M. , Livio M. , Valenti J. , Sowers K.R. , Shukla H.D. , MacAuley S. , Miller T. , Suvanasuthi R. , Belas R. , Colman A. , Robb F.T. , DasSarma P. , Müller J.A. , Coker J.A. , Cavicchioli R. , Chen F. , DasSarma S.
Published: August 2006

Cold environments are common throughout the Galaxy. We are conducting a series of experiments designed to probe the low-temperature limits for growth in selected methanogenic and halophilic Archaea. This paper presents initial results for two mesophiles, a methanogen, Methanosarcina acetivorans, and a halophile, Halobacterium sp. NRC-1, and for two Antarctic cold-adapted Archaea, a methanogen, Methanococcoides burtonii, and a halophile, Halorubrum lacusprofundi. Neither mesophile is active at temperatures below 5 °C, but both cold-adapted microorganisms show significant growth at sub-zero temperatures (−2 °C and −1 °C, respectively), extending previous low-temperature limits for both species by 4–5 °C. At low temperatures, both H. lacusprofundi and M. burtonii form multicellular aggregates, which appear to be embedded in extracellular polymeric substances. This is the first detection of this phenomenon in Antarctic species of Archaea at cold temperatures. The low-temperature limits for both psychrophilic species fall within the temperature range experienced on present-day Mars and could permit survival and growth, particularly in sub-surface environments. We also discuss the results of our experiments in the context of known exoplanet systems, several of which include planets that intersect the Habitable Zone. In most cases, those planets follow orbits with significant eccentricity, leading to substantial temperature excursions. However, a handful of the known gas giant exoplanets could potentially harbour habitable terrestrial moons.
Sea surface temperature–induced cyclogenesis in the Antarctic circumpolar wave
Authors: White Warren B. , Simmonds Ian
Published: August 2006

An Antarctic circumpolar wave (ACW) of 3‐ to‐4‐year period propagated eastward around the Southern Ocean in covarying sea surface temperature (SST) and sea level pressure (SLP) anomalies from 1983 through 1992, composed of two wavelengths that circled most of the global ocean along the midlatitude storm track near 40°S. In this ACW, positive SST anomalies drove upward latent heat flux, positive precipitation (PCP), and mid to upper level diabatic heating anomalies in the troposphere, the latter balanced principally by the cooling tendency from deep convection (White and Chen, 2002). One hypothesis has the anomalous PCP and deep convection in this ACW arising from that in more frequent and/or stronger extratropical cyclones in the synoptic storm aggregate. Here we verify this hypothesis, finding negative SLP anomalies in this ACW collocated with positive extratropical cyclone intensity (ECI) and extratropical cyclone density (ECD) anomalies in the annual synoptic storm aggregate. Because individual extratropical cyclones are 3 to 4 times smaller than SLP anomalies in the ACW, their density and intensity appear to be modulated by anomalous zonal SST gradients in the ACW. These results are corroborated by finding greater interannual PCP anomalies over southeast Australia collocated with positive SST anomalies, occurring on the eastern side of covarying negative SLP and positive ECI and ECD anomalies in the ACW along the mid‐latitude storm track. Because positive interannual PCP anomalies over southeast Australia derive from the integral of rainfall from more dense and/or intense extratropical cyclones in the aggregate, the same is true for the ACW propagating eastward along the midlatitude storm track over the remainder of the Southern Ocean.
Dual‐polarized C‐ and Ku‐band ocean backscatter response to hurricane‐force winds
Authors: Fernandez D. Esteban , Carswell J. R. , Frasier S. , Chang P. S. , Black P. G. , Marks F. D.
Published: August 2006

Airborne ocean backscatter measurements at C‐ and Ku‐band wavelengths and H and V polarizations at multiple incidence angles obtained in moderate to very high wind speed conditions (25–65 m s−1) during missions through several tropical cyclones are presented. These measurements clearly show that the normalized radar cross sections (NRCS) response stops increasing at hurricane‐force winds for both frequency bands and polarizations except for high incidence angles at C‐band and H polarization. The results also show the mean NRCS departing from a power law behavior for all the presented frequency bands, polarizations, and incidence angles, suggesting a reduction in the drag coefficient. The overall flattening of the azimuthal response of the NRCS is also very apparent in all cases. A new set of geophysical model functions (GMFs) at C‐ and Ku‐band are developed from these direct ocean backscatter observations for ocean surface winds ranging from 25 to 65 m s−1. The developed GMFs provide a much more accurate characterization of the NRCS versus wind speed and direction, and their implementation in operational retrieval algorithms from satellite‐based scatterometer observations would result in better wind fields. The differences between these measurements and other currently available GMFs, such as QuikSCAT, NSCAT2, CMOD4, and CMOD5, are reported. The implementation of these GMFs in retrieval algorithms will result in better wind fields from satellite‐based scatterometers measurements.
Passive tracers and active dynamics: A model study of hydrography and circulation in the northern North Atlantic
Authors: Mauritzen C. , Hjøllo S. S. , Sandø A. B.
Published: August 2006

A long‐standing problem in oceanography has been to understand the relationship between what can be measured in the ocean, such as hydrography, and what cannot, such as the strength and structure of the complete Meridional Overturning Circulation (MOC) of the world oceans, commonly considered the main oceanic long‐term modifier of Earth's climate. With the aid of a 50‐year simulation from a numerical ice‐ocean model we have investigated this relationship in the area of the northernmost extension of the MOC, in the subpolar and Nordic seas, on interannual timescales. We find that variability in the northward flux of salt and temperature in this region is controlled almost entirely by the volume flux, confirming that a knowledge of the variability of the circulation strength proper is necessary. The simulated hydrographic anomalies are within the range observed in the twentieth century; thus fundamental changes to the circulation were not expected nor found. It is seen that variability in either temperature or salinity does contain some information about the variability in current strength, because hydrography and circulation generally respond to the same atmospheric forcing in the North Atlantic sector. Whether it is temperature or salinity that contains the information is related to the parameter range of the equation of state at the location in question: If density depends primarily on temperature, then a salinity anomaly will tend to survive and vice versa. The oceanic response involves hydrographic changes and propagation of these, gyre strength changes, and changes in the MOC.
Interannual evolution of seasonal thermohaline properties in the Gulf of Trieste (northern Adriatic) 1991–2003
Authors: Malačič V. , Celio M. , Čermelj B. , Bussani A. , Comici C.
Published: August 2006

Temperature and salinity data, collected by conductivity‐temperature‐depth cruises over the Gulf of Trieste during 1991–2003, were analyzed using different methods. In the first analysis, the evolution within a year of monthly temperatures and salinities at the sea surface and at 10 m depth was examined. Temperature at the surface varies with an annual amplitude of 8.1 ± 0.4°C around 16.5°C, while at a depth of 10 m it varies with an amplitude of 7.0 ± 0.3°C around 15.5°C, the variation being delayed with respect to that at the surface for about 0.4 months. In the second analysis, the interannual variations of seasonal temperatures and salinities were examined. In this northernmost part of the Mediterranean Sea, summer temperatures at the surface between 1991 and 2003 were rising between 0.12 and 0.23°C/year with an error of 0.05°C/year. When the year 2003 with its extremely dry summer period was excluded from the analysis, the trend is reduced to 0.07–0.09°C/year (±0.06°C/year). Winter temperatures, however, demonstrate an increasing trend from near zero to 0.10°C/year ± 0.14°C/year when year 2003 was excluded from the analysis. Similar changes in trends have been observed for air temperatures. Summer temperatures at a depth of 10 m have a more reliable positive trend: 0.22–0.23°C/year (±0.08°C/year). Salinities obtained from the objective analysis show a most pronounced positive trend of 0.28–0.34 year−1 (±0.16 year−1). When 2003 is excluded from the analysis, this value decreased to 0.22–0.28 year−1 with an error of 0.09 year−1.
Improved modeling of Lunar Prospector neutron spectrometer data: Implications for hydrogen deposits at the lunar poles
Authors: Lawrence David J. , Feldman W. C. , Elphic R. C. , Hagerty J. J. , Maurice S. , McKinney G. W. , Prettyman T. H.
Published: August 2006

New models have been computed for the Lunar Prospector (LP) thermal and epithermal neutron counting rates using the particle transport code MCNPX. This work improves upon previous studies by using one code to model the neutron production, transport, and detection processes, and by examining the sensitivity of epithermal neutrons to elements other than hydrogen. Our modeling results for standard anhydrous lunar soils show that when hydrogen is not included in a soil, epithermal neutrons are most sensitive to variations in the abundances of Fe, Gd, and Sm, which is consistent with measured epithermal neutron data. We use our current modeling results, in conjunction with known mineral compositions of lunar soils and other lunar global data sets to conclude that the best explanation for a decrease in the counting rate of epithermal neutrons near both lunar poles is the presence of hydrogen. We have further concluded that the average hydrogen abundance near both lunar poles is 100–150 ppm and is likely buried by 10 ± 5 cm of dry lunar soil, a result that is consistent with previous studies. The localized hydrogen abundance for small (<20 km) areas of permanently shaded regions remains highly uncertain and could range from 200 ppm H up to 40 wt% H2O in some isolated regions.
Nutrient control of microbial carbon cycling along an ombrotrophic‐minerotrophic peatland gradient
Authors: Keller Jason K. , Bauers Angela K. , Bridgham Scott D. , Kellogg Laurie E. , Iversen Colleen M.
Published: August 2006

Future climate change and other anthropogenic activities are likely to increase nutrient availability in many peatlands, and it is important to understand how these additional nutrients will influence peatland carbon cycling. We investigated the effects of nitrogen and phosphorus on aerobic CH4oxidation, anaerobic carbon mineralization (as CO2and CH4production), and anaerobic nutrient mineralization in a bog, an intermediate fen, and a rich fen in the Upper Peninsula of Michigan. We utilized a 5‐week laboratory nutrient amendment experiment in conjunction with a 6‐year field nutrient fertilization experiment to consider how the relative response to nitrogen and phosphorus differed among these wetlands over the short and long term. Field fertilizations generally increased nutrient availability in the upper 15 cm of peat and resulted in shifts in the vegetation community in each peatland. High nitrogen concentrations inhibited CH4oxidation in bog peat during short‐term incubations; however, long‐term fertilization with lower concentrations of nitrogen stimulated rates of CH4oxidation in bog peat. In contrast, no nitrogen effects on CH4oxidation were observed in the intermediate or rich fen peat. Anaerobic carbon mineralization in bog peat was consistently inhibited by increased phosphorus availability, but similar phosphorus additions had few effects in the intermediate fen and stimulated CH4production and nutrient mineralization in the rich fen. Our results demonstrate that nitrogen and phosphorus are important controls of peatland microbial carbon cycling; however, the role of these nutrients can differ over the short and long term and is strongly mediated by peatland type.
Development of the enhanced self‐adaptive hybrid genetic algorithm (e‐SAHGA)
Authors: Espinoza Felipe P. , Minsker Barbara S.
Published: August 2006

Genetic algorithms allow solution of more complex, nonlinear groundwater remediation design problems than traditional gradient‐based approaches, but they are more computationally intensive. One way to improve performance is through inclusion of local search, creating a hybrid genetic algorithm (HGA). The inclusion of local search helps to speed up the solution process and to make the solution technique more robust. This technical note focuses on the development and application of a new HGA, the enhanced self−adaptive hybrid genetic algorithm (e‐SAHGA), which is an enhancement of a previously developed HGA called SAHGA. The application of the e‐SAHGA algorithm to a hypothetical groundwater remediation design problem showed 90% reliability in identifying the optimal solution faster than the SGA, with average savings of 64% across 100 random initial populations. These results are considerably improved over SAHGA, which attained only 80% reliability and 14% average savings on the same initial populations.
Spatial patterns of scour and fill in dryland sand bed streams
Authors: Powell D. Mark , Brazier Richard , Wainwright John , Parsons Anthony , Nichols Mary
Published: August 2006

Spatial patterns of scour and fill in two dryland ephemeral stream channels with sandy bed material have been measured with dense arrays of scour chains. Although the depth and areal extent of bed activity increased with discharge, active bed reworking at particular locations within the reaches resulted in downstream patterns of alternate shallower and deeper areas of scour. The variation was such that mean scour depths for individual cross sections varied about the mean for the reach by a factor of 2–4 while the locus of maximum scour traced a sinuous path about the channel centerline. The wavelength of the pattern of scour was about seven times the channel width. During each event, compensating fill returned the streambeds to preflow elevations, indicating that the streams were in approximate steady state over the period of study. Although the patterns of periodically enhanced scour along alternate sides of the channels are consistent with models of periodically reversing helical flow, further work is required to identify the causal relationships between patterns of flow and sediment transport in dryland sand bed channels.
A mixed finite element technique based on implicit discretization of faults for permeability upscaling in fault damage zones
Authors: Ma Jingsheng , Couples Gary D. , Harris Simon D.
Published: August 2006

Natural fault damage zones (FDZs) are often composed of complex arrays containing many thin faults. To account for FDZs in large‐scale models, it is necessary to represent the flow effects of these many small faults by some form of upscaling. The explicit discretization of the geometry and topology of these thin faults and of the rock matrix typically leads to meshes comprising large numbers of elements, making it difficult to solve the flow equations efficiently. This paper proposes a practical technique based on the mixed finite element method (MFEM), permitting the permeability upscaling in two‐dimensional fault damage zones that contain thin and isotropic low‐permeability faults. This technique utilizes an implicit discretization scheme that is similar in principle to those used for discrete fracture networks. The scheme described here treats flow across faults accurately, but, unlike the schemes used for fractures, it neglects the flow along the faults because intrafault volumetric flow in thin faults is very small. This approach allows for a simpler numerical discretization and a reduction in numerical calculation effort. The scheme can be readily implemented in a standard mixed finite element code. Compared with the same MFEM based on an explicit discretization scheme, the two techniques are shown to produce results that agree closely. The implicit technique is shown to be more efficient than the explicit technique for a typical fault damage zone model. This technique is readily extendable to three dimensions.
Evolution of submicron organic aerosol in polluted air exported from Tokyo
Authors: Takegawa N. , Miyakawa T. , Kondo Y. , Blake D. R. , Kanaya Y. , Koike M. , Fukuda M. , Komazaki Y. , Miyazaki Y. , Shimono A. , Takeuchi T.
Published: August 2006

Ground‐based measurements of aerosols and trace gases were conducted at an urban site in Tokyo (Komaba) and a site 50 km to the north (Kisai) during July–August 2004. An Aerodyne aerosol mass spectrometer (AMS) was deployed at each measurement site to investigate the chemical evolution of submicron organic aerosol (OA) in polluted air. The mass concentrations of OA at the Kisai site were systematically higher than those at the Komaba site and were correlated with ozone under southerly conditions. The rate of increase of OA at the Kisai site is investigated using the photochemical age derived from the ratio of alkyl nitrates to their parent hydrocarbons. The OA concentrations in processed air (age of 8–16 h) were 4–5 times larger than those in fresh emissions (age ∼ 0), suggesting that the OA concentrations can be significantly enhanced within ∼0.5 days under conditions of high photochemical activity.
Sea surface salinity constrains rainfall estimates over tropical oceans
Authors: Yaremchuk M.
Published: August 2006

Uncertainties in the monthly mean estimates of precipitation are the largest over oceanic regions with the heaviest rainfall. Using the adjoint sensitivity analysis and 4d variational assimilation of sea surface salinity (SSS) into an ocean model, we show that rainfall estimation errors in the regions of heavy precipitation could be reduced by taking SSS observations into account. Inverse analysis of SSS in the Bay of Bengal also indicates that the monthly mean rainfall of the Global Precipitation Climatology Project (GPCP) is more consistent with SSS and river runoff data than other precipitation climatologies.
An aerosol transport model based on a two‐moment microphysical parameterization in the Venus middle atmosphere: Model description and preliminary experiments
Authors: Yamamoto Masaru , Takahashi Masaaki
Published: August 2006

On Venus, the upper haze layer (70–90 km) is observed above the cloud layer (48–70 km). An aerosol transport model using a two‐moment microphysical parameterization for the cloud and upper haze is developed and is applied to a wide height range of 24–94 km. The latitudinal dependence of the SO2 oxidation mainly leads to the equator‐pole contrast of the aerosol mass loading, and the meridional circulation weakens the equator‐pole contrast of the mass loading through the poleward mass transport. The equator‐pole contrast of the aerosol number concentration is enhanced by the meridional circulation in the middle atmosphere. The haze transport due to the meridional circulation should be considered as an important process in the formation of the equator‐pole contrast of the Venus cloud structure.
Soil microbial biomass, labile and total carbon levels of grazed sown and native pastures in northern New South Wales
Authors: Lodge G. M. , King K. L.
Published: August 2006

Studies were conducted at 3 pasture sites in northern New South Wales to examine the effects of grazing treatments over 4 years (spring 1997 to spring 2001) on soil microbial biomass carbon (C), labile C, total C, and total nitrogen (N). These data were collected (0–0.05 m soil depth) at 9 sampling times in 2 replicates of 5 (native pastures) or 4 (a sown pasture) grazing treatments and examined for differences over time using cubic spline analyses. For each site, differences among grazing treatments were also examined in spring 2001 for herbage, litter, and root mass (kg DM/ha), ground cover (%), and perennial grass basal cover (%). Indices were also calculated for the C pool index (CPI), lability index (LI), a carbon management index (CMI), and the microbial quotient. Relationships among microbial biomass C, labile C, total organic C, CPI, LI, CMI, microbial quotient, herbage mass, litter mass, and ground cover were examined by linear regression and correlation analyses.
For each of the sites, treatment differences in the linear trend over time for soil microbial biomass C, labile C, total organic C, or total N were not significantly different (P > 0.05). In spring 2001, (4 years after treatments commenced) there were also no significant effects of treatments within sites on soil total organic C and none of the indices (lability of C, CPI, LI, CMI, or the microbial quotient) indicated any distinct trends among treatments. However, in spring 2001, there were significant (P < 0.05) treatment effects at both native pasture sites for herbage mass, litter mass, and ground cover. Similarly, in autumn 2001, herbage mass, root mass, and perennial grass basal cover were lowest (P < 0.05) in the continuously grazed high-stocking rate treatment at the sown pasture site. For all data, microbial biomass C was 10.35% of labile C and labile C was 21.60% of total C. From autumn 1998 to spring 2001, labile C was positively correlated (P < 0.05) with total C (r = 0.72) and in spring 2001, these 2 variables were also highly correlated (r = 0.98).
Comparative water use by Dorycnium hirsutum-, lucerne-, and annual-based pastures in the Western Australian wheatbelt
Authors: Bell Lindsay W. , Ryan Megan H. , Moore Geoff A. , Ewing Mike A.
Published: August 2006

Dryland salinity in southern Australia has been caused by inadequate water use by annual crops and pastures. The purpose of this study was to compare the water use of annual pastures and Medicago sativa L. (lucerne) with Dorycnium hirsutum (L.) Ser., a potential new perennial forage species. The soil water dynamics under bare ground, annual legume-, lucerne-, and D. hirsutum-based pastures were compared at 2 sites in the low- (Merredin) and medium- (New Norcia) rainfall wheatbelt of Western Australia between September 2002 and February 2005.
Soil under D. hirsutum was drier than under annual pastures by 8–23 mm in Year 1, 43–57 mm in Year 2, and 81 mm in Year 3. Lucerne used little additional water (<19 mm, n.s.) compared with D. hirsutum and profile soil water content was similar under both species throughout the experiment. At Merredin, annual pastures used water to a depth of 1.0 m, whereas under both D. hirsutum and lucerne in the first 3 years after establishment the successive maximum depth of water use was 1.0, 1.8, and 2.2 m. At New Norcia, additional soil water was extracted by lucerne and D. hirsutum at depths <1.0 m and no difference between treatments was detected below 1.0 m. Biomass of D. hirsutum pasture harvested in autumn contained minimal annual components and was 15–50% of that produced by lucerne- or annual legume-based pastures. D. hirsutum and lucerne plant density declined each summer (25–80%), but D. hirsutum density was lower than lucerne due to poorer establishment. Nonetheless, the comparable water use of lucerne and D. hirsutum suggests that D. hirsutum could make reductions in recharge similar to those of lucerne in the Western Australian wheatbelt.
Archaeal nitrification in the ocean
Authors: Wuchter Cornelia , Abbas Ben , Coolen Marco J. L. , Herfort Lydie , van Bleijswijk Judith , Timmers Peer , Strous Marc , Teira Eva , Herndl Gerhard J. , Middelburg Jack J. , Schouten Stefan , Sinninghe Damsté Jaap S.
Published: August 2006

Marine Crenarchaeota are the most abundant single group of prokaryotes in the ocean, but their physiology and role in marine biogeochemical cycles are unknown. Recently, a member of this clade was isolated from a sea aquarium and shown to be capable of nitrification, tentatively suggesting that Crenarchaeota may play a role in the oceanic nitrogen cycle. We enriched a crenarchaeote from North Sea water and showed that its abundance, and not that of bacteria, correlates with ammonium oxidation to nitrite. A time series study in the North Sea revealed that the abundance of the gene encoding for the archaeal ammonia monooxygenase alfa subunit (
amoA
) is correlated with a decline in ammonium concentrations and with the abundance of Crenarchaeota. Remarkably, the archaeal
amoA
abundance was 1–2 orders of magnitude higher than those of bacterial nitrifiers, which are commonly thought to mediate the oxidation of ammonium to nitrite in marine environments. Analysis of Atlantic waters of the upper 1,000 m, where most of the ammonium regeneration and oxidation takes place, showed that crenarchaeotal
amoA
copy numbers are also 1–3 orders of magnitude higher than those of bacterial
amoA
. Our data thus suggest a major role for Archaea in oceanic nitrification.
Monte Carlo studies of surface chemistry and nonthermal desorption involving interstellar grains
Authors: Herbst Eric , Cuppen Herma M.
Published: August 2006

Although still poorly understood, the chemistry that occurs on the surfaces of interstellar dust particles profoundly affects the growth of molecules in the interstellar medium. The most important surface reaction is the conversion of atomic to molecular hydrogen, which is a precursor for all subsequent molecular development and which occurs both in diffuse and dense interstellar clouds. Another set of surface reactions produces icy mantles of many monolayers in cold and dense regions of the interstellar medium. The monolayers are dominated by water ice but also contain CO, CO
2
, and occasionally methanol. In this work, we first review both our stochastic approach to the surface chemistry that can occur on small dust particles and how it has been applied to the problem of the formation of molecular hydrogen. This latter problem is strongly affected by the pulsed heating of smaller grains by photons. Photons are not the only source of pulsed heating; cosmic rays also can heat interstellar grains in a pulsed manner. Here, we calculate the heating by cosmic rays for different grain sizes and cosmic ray components. It is then shown that this mechanism is an important one for desorption of ice mantles.