bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of hedging on reservoir performance
Authors: Bayazit M. , Ünal N. E.
Published: February 2008

The effects of operating a water supply reservoir with a policy of hedging on various reservoir performance criteria are investigated. The results of simulations where policies with different degrees of hedging are adopted are used to determine how reliability, resiliency, and mean and maximum deficit vary as functions of hedging parameters and to derive the relationships between these criteria. It is found that the standard operating policy is the best in relation to reliability and resiliency and is satisfactory with regard to deficits. Hedging improves the performance with respect to mean deficit if it is started with sufficient water in storage. If hedging is applied when there is little water in storage, it reduces the risk of very large future deficits, although the mean deficit will be increased. If hedging is continued even when the demand can be supplied, the performance of the reservoir will be more stable and the mean deficit will be decreased, but these will be achieved at a cost of increasing the rate of failure.
Optimal pumping test design for parameter estimation and prediction in groundwater hydrology
Authors: McCarthy James M. , Yeh William W‐G.
Published: February 2008

A systematic approach is developed to design a least cost aquifer pumping test. Systematic pumping test design evaluates the acceptability of all potential pumping test data sets, before actually performing the test. In this way, various acceptable pumping test designs can be compared in order to choose the least cost acceptable alternative. This research utilizes δ identifiability as the acceptability criterion, such that, for a pumping test design to be acceptable, the parameters identified from the pumping test data set must predict some overall management objective within a prescribed error. The pumping test design problem is assumed to be a function of the number and location of the pumping and observation wells, as well as the pumping test pump rate, duration and measurement pattern. Using practical considerations and an evaluation of the pumping test design problem's response, the optimization problem is reduced to three decision variables: (1) the number of observation wells; (2) observation well locations, and (3) the pumping test pump rate. Values for the remaining decision variables are chosen and sensitivity analysis is used to evaluate their effects on the pumping test design problem. The pumping test design problem is decomposed into a main optimization problem and one subproblem. The main problem minimizes the number of observation wells by choice of their location, while the subprobiem minimizes the pumping test pump rate subject to (1) a maximum pump rate, and (2) the δ identifiability constraint.
A state‐space model for hydrologic river routing
Authors: Georgakakos Aris P. , Georgakakos Konstantine P. , Baltas Evangelos A.
Published: February 2008

In this paper a state‐space formulation of the Muskingum‐Cunge routing scheme is proposed. The state‐space formulation utilizes real‐time discharge measurements, accounts for modeling and observation errors, and allows real‐time updating through a Kalman filter estimator. The new model is tested in two different geotechnical conditions to forecast six‐hour discharge values in hypothetical channels. For realism, the geomorphologic characteristics of these case studies are determined on the basis of the regime theory. DWOPER, a field‐tested numerical dynamic routing model, was used to provide ground truth data for the validation of the proposed model.
Diffusion coefficients in gravel under unsaturated conditions
Authors: Conca James L. , Wright Judith
Published: February 2008

Diffusion coefficients were experimentally determined in unsaturated gravel to evaluate the effectiveness of gravel as a diffusion barrier to ionic transport in the vadose zone. Water contents were fixed by use of an ultracentrifuge with an ultralow constant rate flow pump supplying solution to the sample via a rotating seal. Once the gravel was at hydraulic steady state, the electrical conductivity was measured, and the diffusion coefficient calculated using the Nernst‐Einstein equation. Diffusion coefficient values for potassium ion (De) in four types of angular gravel ranged from 1.7 × 10−11 m2/s (1.7 × 10−7 cm2/s) for a 6.3–9.5 mm angular granitic gravel at a volumetric water content of 5.5% to 2.2 × 10−14 m2/s (2.2 × 10×10 cm2/s) in a 4.0–6.3 mm quartzite gravel at a volumetric water content of 0.47%. Variations in De values resulted primarily from differences in water content which depends on gravel type and particle size.
An ecohydrological framework for water yield changes of forested catchments due to forest decline and soil acidification
Authors: Caspary H. J.
Published: February 2008

The effect of forest decline on water resources is not well described, for there have been no long‐term measurements on catchments with declining forests. The precipitation/runoff relationship of the declining forests of the Eyach catchment in the Northern Black Forest/Federal Republic of Germany is analyzed. The uninhabited catchment is subdivided into four subcatchments (7, 10, 30, 52 km2) and is totally covered with coniferous forest, mostly Norway spruce. Long‐term monitoring from 1973 to 1986 indicates a significant increase in water yield and the runoff coefficient for the growing season, although there has been no extensive cutting in the catchment. An “ecohydrological systems model” was developed by the incorporation of field data and plant physiological processes to describe the increase in water yield. Field data include hydrological, hydrogeological, geological, soil‐physical, soil‐chemical, water‐chemical, air‐chemical, pollutant deposition, forest inventory, and forest decline field measurements from the Eyach catchment and comparable neighboring regions. The model indicates that the observed increase in water yield is likely to be caused by a reduction of forest transpiration. This change in water yield is linked to forest decline and soil acidification caused by anthropogenic sources of air pollution.
On thermohydrologic conditions near high‐level nuclear wastes emplaced in partially saturated fractured tuff: 1. Simulation studies with explicit consideration of fracture effects
Authors: Pruess K. , Wang J. S. Y. , Tsang Y. W.
Published: February 2008

We have performed modeling studies on the simultaneous transport of heat, liquid water, vapor, and air in partially saturated, fractured porous rock. Formation parameters were chosen as representative of the potential nuclear waste repository site in the Topopah Spring unit of the Yucca Mountain tuffs. The presence of fractures makes the transport problem very complex, both in terms of flow geometry and physics. The numerical simulator used for our flow calculations takes into account most of the physical effects believed to be important in multiphase fluid and heat flow. It has provisions for handling the extreme nonlinearities that arise in phase transitions, component disappearances, and capillary discontinuities at fracture faces. We model a region around an infinite linear string of nuclear waste canisters, taking into account both the discrete fractures and the porous matrix. Thermohydrologic conditions in the vicinity of the waste packages are found to depend strongly on relative permeability and capillary pressure characteristics of the fractures, which are unknown at the present time. If liquid held on the rough walls of drained fractures is assumed to be mobile, strong heat pipe effects are predicted. Under these conditions the host rock will remain in two‐phase conditions right up to the emplacement hole, and formation temperatures will peak near 100°C. If it is assumed that liquid cannot move along drained fractures, the region surrounding the waste packages is predicted to dry up, and formation temperatures will rise beyond 200°C. A substantial fraction of waste heat can be removed if emplacement holes are left open and ventilated, as opposed to backfilled and sealed emplacement conditions. Comparing our model predictions with observations from in situ heater experiments reported by Zimmerman and coworkers, some intriguing similarities are noted. However, for a quantitative evaluation, additional carefully controlled laboratory and field experiments will be needed.
Transport and sedimentation of pollutants in a river reach: A chemical mass balance approach
Authors: Berndtsson Ronny
Published: February 2008

The River Höje in the south of Sweden is a typical receiving water for urban and rural runoff. Mass balance calculations over a 17‐month period indicate that pollutants are retained in the sediments of the investigated 5‐km‐long reach of the stream (90 tons of biochemical oxygen demand (BOD7), 850 tons of chloride, 2.1 tons of copper, 3.2 tons of zinc, and 1.0 ton of lead). Other pollutants such as suspended solids and phosphorus appear to be both retained and washed‐out, depending on loading rates and local stream conditions. The retained pollutants represent a substantial part of the total mass transport through the stream (14–47%). Almost half of the transported zinc is retained within the stream sediment. Subsequently, the deposited pollutants represent a potential pollution source. Analyses of sediment samples verify that the upper sediments contain high concentrations of heavy metals.
Deterministic signals in precipitation in the northwestern United States
Authors: Currie Robert G. , O'Brien Douglas P.
Published: February 2008

Evidence for the 18.6‐year lunisolar MN signal is found in 91 out of 102 rain gauge records (89% detection ratio) in the states of Montana, Wyoming, and Idaho, while the 10‐ to 11‐year solar cycle SC term is detected in 67 of these time series (66% detection ratio). Lunar nodal 19‐year MN wave trains for these three states show complex patterns, with many experiencing a bistable 180° phase switch at epoch 1973.3 (epochs are dates of maximum in tidal forcing). At epoch 1954.7 ± 2.5 years, Wyoming, Montana, and eastern Idaho experienced drought conditions. By epoch 1973.3 ± 2.5 years, a wet cell of opposite polarity had invaded the eastern half of Montana and parts of eastern Wyoming; concomitantly, drought had expanded westward to include virtually all of Idaho. Bistable 180° phase switches in climate parameters were first reported in Patagonian tree ring data (Currie, 1983) and were later found for a flood index in India (Currie, 1984a), a drought index for Beijing (Currie and Fairbridge, 1985), in flooding of the Nile and St. Lawrence rivers (Currie, 1987a; Currie and O'Brien, 1989), in air temperature and air pressure records worldwide (Currie, 1987b), and in rainfall for the northeastern United States and the corn belt (Currie and O'Brien, 1989, 1990).
Logging effects on streamflow: Storm runoff at Caspar Creek in northwestern California
Authors: Wright Kenneth A. , Sendek Karen H. , Rice Raymond M. , Thomas Robert B.
Published: February 2008

The effects of road building and selective tractor harvesting on storm runoff were assessed for a small (424 ha) coastal watershed in northern California. Road building alone did not significantly affect the storm runoff. After road building and logging, lag time was decreased approximately 1.5 hours, and the very small storm volumes (less than 1209 m3) and storm peaks (less than 566 L/s) were increased by about 132 and 111%, respectively. Storm volumes and peaks of large storms (occurring less frequently than eight times a year) were not significantly increased by either roads or logging, even though more than 15% of the watershed was compacted in roads, skid trails, and landings. Although a decrease in lag time showed that the average storm hydrograph was shifted forward in time, only the small storm hydrographs were changed in shape. We speculate that the rate of delivery of water to the stream channel during large channel‐forming flows was governed by infiltration and subsurface flow rates on the 85% of the watershed that was unaffected by roads, landings, or skid trails. From these findings we conclude that, in a rain‐dominated hydrologic environment, logging and forest road construction (as carried out in this study) are not likely to change the flow regime of a stream adversely.
Depressional storage for Markov‐Gaussian surfaces
Authors: Huang Chi‐hua , Bradford Joe M.
Published: February 2008

Processes during rain events, such as infiltration, runoff, soil erosion, and crust formation, are influenced in part by depressional storage and surface roughness. If the surface topography is known, its potential depressional storage can be calculated. The objective of this paper was to relate the statistical parameters for quantifying surface roughness to depressional storage. Analysis of topographic data sets digitized at millimeter grids by a laser scanner showed that soil roughness can be quantified by a Markov‐Gaussian (M‐G) type random process. A Monte Carlo simulation procedure was used to find the mean ponding characteristics from simulated M‐G surfaces. Depressional storages were found to be functions of two M‐G parameters, two sample length scales, and the slope steepness. The Markov parameters are the global variance (σ2) and the correlation length scale (L), and the sample length scales are grid spacing (Δx) and side length (Ls). After proper scaling, all storage functions collapsed into two nondimensional relationships: (1) storage at zero slope as a function of relative sample length scale, and (2) storage as a function of scaled slope. When L = 0, simulated surfaces followed the random Gaussian model and the nondimensional storage was only a function of scaled slope. Storages calculated from digitized elevation data sets with M‐G type statistics agreed well with results obtained from simulated surfaces.
A computer‐controlled 36‐channel time domain reflectometry system for monitoring soil water contents
Authors: Heimovaara T. J. , Bouten W.
Published: February 2008

Research on the spatial and temporal dynamics of soil water has long been impeded by the lack of an automated technique for the measurement of soil water content. A computer controlled time domain reflectometry (TDR) system is described which gives the possibility of making a large number of measurements at different sites at predetermined time intervals. The developed system operates on 12 V dc and has the capability to monitor water contents at 36 sites. The algorithm used for the automatic analysis of the measurements is also presented. It is based on the calculation of the travel time of the TDR signal between the beginning and the end of a three‐wire probe.
Set Membership Approach to Identification and Prediction of Lake Eutrophication
Authors: Keesman Karel , van Straten Gerrit
Published: February 2008

Generally, ecosystems modeling is obstructed by the problem of sparse and unreliable data, and lack of knowledge about processes dominating the system. Under these circumstances, set theoretic uncertainty models are an appropriate alternative to probabilistic models. The only requirement is that the uncertainty is pointwise bounded. A newly developed set membership identification procedure is presented and demonstrated by an application to the modeling of shallow lake eutrophication. First, a set of parameter vectors is identified. Analysis of the set reveals a dominant direction spanned by four algal growth and death parameters. Second, on the basis of additional fuzzy set theoretic assumptions, a formal min‐max estimation is performed to obtain information about the model validity. If the model appears to be (partially) invalid, the degree of invalidity, affecting the model prediction uncertainty, can be represented by an estimate of the model structure error in addition to the uncertainty contained in the identified set of parameter vectors.
Dissolved Organic Carbon Cycling in Forested Watersheds: A Carbon Isotope Approach
Authors: Schiff S. L. , Aravena R. , Trumbore S. E. , Dillon P. J.
Published: February 2008

Dissolved organic carbon (DOC) is important in the acid‐base chemistry of acid‐sensitive freshwater systems; in the complexation, mobility, persistence, and toxicity of metals and other pollutants; and in lake carbon metabolism. Carbon isotopes (13C and 14C) are used to study the origin, transport, and fate of DOC in a softwater catchment in central Ontario. Precipitation, soil percolates, groundwaters, stream, beaver pond, and lake waters, and lake sediment pore water were characterized chemically and isotopically. In addition to total DOC, isotopic measurements were made on the humic and fulvic DOC fractions. The lake is a net sink for DOC. Δ14C results indicate that the turnover time of most of the DOC in streams, lakes, and wetlands is fast, less than 40 years, and on the same time scale as changes in acidic deposition. DOC in groundwaters is composed of older carbon than surface waters, indicating extensive cycling of DOC in the upper soil zone or aquifer.
Electronic transport and layer engineering in multilayer graphene structures
Authors: Wang H. M. , Wu Y. H. , Ni Z. H. , Shen Z. X.
Published: February 2008

We demonstrate a reproducible layer engineering technique for multilayer graphene through controllable oxidation via a SiO2 capping layer. The oxidation method is able to reduce the thickness of few layer graphene to a single layer, as determined by a combination of contrast and Raman spectroscopies. We have also studied the electrical transport properties of graphene sheets with different thicknesses by focusing on their minimum conductivity. The average minimum conductivity of single layer graphene was found to be 0.3×4e2∕h, while that of multilayer graphene consisting of n layers is approximately 1.2×4e2∕h for n=2, 2.4×4e2∕h for n=3, and 4ne2∕h for n>3. The results suggest that the substrate plays an important role in determining the transport properties of thin graphene sheets with n<3, while its influence is relatively small in thicker graphene sheets.
Superconducting properties of nanocrystalline Nb3Al in Nb–Al matrix
Authors: Mondal Puspen , Manekar Meghmalhar , Kumar Ravi , Ganguli Tapas , Roy S. B.
Published: February 2008

We present the results of x-ray diffraction and magnetization measurements on the nanocrystalline as-cast compound Nb3Al. X-ray diffraction shows the presence of the A15 Nb3Al phase embedded in a matrix of a bcc Nb–Al solid solution. The average grain size of Nb3Al estimated from the line broadening is about 35nm. Magnetization measurements give a lower limit of the superconducting transition temperature to be about 16.8K, which is amongst the highest known TC for the as-cast sample of Nb3Al. In the superconducting state, the sample shows anomalous thermomagnetic history effects in the temperature and field variation of magnetization.
Superinfection as a driver of genomic diversification in antigenically variant pathogens
Authors: Futse James E. , Brayton Kelly A. , Dark Michael J. , Knowles Donald P. , Palmer Guy H.
Published: February 2008

A new pathogen strain can penetrate an immune host population only if it can escape immunity generated against the original strain. This model is best understood with influenza viruses, in which genetic drift creates antigenically distinct strains that can spread through host populations despite the presence of immunity against previous strains. Whether this selection model for new strains applies to complex pathogens responsible for endemic persistent infections, such as anaplasmosis, relapsing fever, and sleeping sickness, remains untested. These complex pathogens undergo rapid within-host antigenic variation by using sets of chromosomally encoded variants. Consequently, immunity is developed against a large repertoire of variants, dramatically changing the scope of genetic change needed for a new strain to evade existing immunity and establish coexisting infection, termed strain superinfection. Here, we show that the diversity in the alleles encoding antigenic variants between strains of a highly antigenically variant pathogen was equal to the diversity within strains, reflecting equivalent selection for variants to overcome immunity at the host population level as within an individual host. This diversity among strains resulted in expression of nonoverlapping variants that allowed a new strain to evade immunity and establish superinfection. Furthermore, we demonstrated that a single distinct allele allows strain superinfection. These results indicate that there is strong selective pressure to increase the diversity of the variant repertoire beyond what is needed for persistence within an individual host and provide an explanation, competition at the host population level, for the large genomic commitment to variant gene families in persistent pathogens.
Working Alliances in College Classrooms
Authors: Meyers Steven A.
Published: February 2008

I explain how professors can establish working alliances with students to cultivate a climate conducive to learning. This process involves (a) attending to the emotional bonds that exist in the college classroom, (b) developing shared educational goals and tasks to promote a common sense of purpose, and (c) addressing classroom conflict to repair disruptions in social relationships. I also describe how working alliance theory extends our knowledge and practice of effective teaching.
Using Wireless Response Systems to Replicate Behavioral Research Findings in the Classroom
Authors: Cleary Anne M.
Published: February 2008

College instructors are increasingly relying on wireless clicker systems as instructional tools in the classroom. Instructors commonly use clicker systems for such classroom activities as taking attendance, giving quizzes, and taking opinion polls. However, these systems are uniquely well suited for the teaching of psychology and other courses that emphasize behavioral research methods. Specifically, instructors can use the clicker system to engage students in an in-class replication of a known empirical phenomenon. This article describes 2 classroom demonstrations that reveal the usefulness of wireless clicker systems for replicating empirical phenomena in behavioral research.
Ratings of perceived exertion and oxygen consumption during maximal, graded, treadmill exercise following different anchoring procedures
Authors: Gearhart Randall F.
Published: February 2008

In this study, relative oxygen consumption (VO2) was compared at selected criterion ratings of perceived exertion (RPE) during maximal, graded, treadmill exercise following memory or combined exercise and memory anchoring to the Borg 15‐category scale. The purpose was to determine whether participants would produce a similar relative VO2 at a corresponding criterion RPE following different types of anchoring. Thirty‐six college‐aged participants (18 males, 18 females) volunteered for this investigation and were assigned to one of two groups: a memory anchoring group or a combined exercise and memory group. The memory anchoring group received only verbal instructions before the experimental trial. The combined exercise and memory group received identical verbal instructions to the memory anchoring group, which were administered initially while the participants performed a graded treadmill test to exhaustion. The low perceptual anchor (i.e. 7) was established during light walking and the high perceptual anchor (i.e. 19) at volitional exhaustion. Similar to that for the memory anchoring group, the memory anchoring instructions were presented immediately before the experimental trial for the combined exercise and memory group. Linear regression was used to calculate percent VO2peak for each criterion RPE (7, 9, 11, 13, 15, 17, and 19). Independent samples t‐tests were used to compare percent VO2peak between the two groups at each criterion RPE. Percent VO2peak did not differ (P>0.05) between the two groups at any criterion RPE. Both types of anchoring instructions can be considered valid tools in applying the Borg scale to this population Memory anchoring may be preferred because it involves one less laboratory session for both the investigator and the participant.
Mortality rate acceleration and post-reproductive lifespan in matrilineal whale species
Authors: Foote Andrew D
Published: February 2008

The strength of selection to increase the span of a life stage is dependent upon individuals at that stage being able to contribute towards individual fitness and the probability of their surviving to that stage. Complete reproductive cessation and a long post-reproductive female lifespan as found in humans are also found in killer whale (
Orcinus orca
) and short-finned pilot whale (
Globicephala macrorhynchus
), but not in the long-finned pilot whale (
Globicephala melaena
). Each species forms kin-based, stable matrilineal groups and exhibits kin-directed behaviours that could increase inclusive fitness. Here, the initial mortality rate and mortality rate-doubling time of females of these three closely related whale species are compared. The initial mortality rate shows little variation among pilot whale species; however mortality rate accelerates almost twice as fast in the long-finned pilot whale as it does in killer whale and short-finned pilot whale. Selection for a long post-reproductive female lifespan in matrilineal whales may therefore be determined by the proportion of females surviving past the point of reproductive cessation.
Heterogeneity in intertidal fish fauna assemblages along the world’s longest mangrove area in northern Brazil
Authors: Giarrizzo T. , Krumme U.
Published: February 2008

The first comparison of the intertidal fish fauna from three estuaries within the longest contiguous mangrove area of the world, in north Brazil, revealed a significant heterogeneity in the species composition and functional and ecological guilds with an increase of Tetraodontidae and Engraulidae and a decrease of Sciaenidae and Mugilidae towards the Amazon mouth. A classification of the mangrove estuaries to identify types of estuaries and coastal sectors is urgently required to provide a tool for regional management systems in order to improve research, monitoring and conservation of this unique mangrove ecosystem.
Expression of retinoic acid receptors in human endometrial carcinoma
Authors: Tanabe Kojiro , Utsunomiya Hiroki , Tamura Mitsutoshi , Niikura Hitoshi , Takano Tadao , Yoshinaga Kohsuke , Nagase Satoru , Suzuki Takashi , Ito Kiyoshi , Matsumoto Mitsuyo , Hayashi Shin‐ichi , Yaegashi Nobuo
Published: February 2008

The retinoids (vitamin A and its biologically active derivatives) are essential for the health and survival of the individual. Several studies have reported a strong rationale for the use of retinoids in cancer treatment and chemoprevention. It has been discovered that expression of retinoic acid receptor (RAR) β is frequently silenced in epithelial carcinogenesis, which has led to the hypothesis that RARβ could act as a tumor suppressor. However, the status of RARβ in human endometrial carcinoma has not been examined. In the present study, we initially studied the effects of retinoic acid on cell proliferation and the expression of RARα, RARβ, and RARγ using AM580 (a RAR‐specific agonist) in the Ishikawa endometrial cancer cell line. We also examined the expression of RAR in human eutopic endometrium (30 cases), endometrial hyperplasia (28 cases), and endometrial carcinoma (103 cases) using immunohistochemistry. Finally, we correlated these findings with the clinicopathological parameters. In vitro, cell growth was inhibited and RARβ and RARγ mRNA was significantly induced by AM580, compared with vehicle controls, whereas RARα mRNA was significantly attenuated by AM580, compared with vehicle. RARβ was detected predominantly in endometrial hyperplasia, compared with endometrial carcinoma. No statistically significant correlation was obtained between the expression of any other RAR subtypes and clinicopathological parameters in human endometrial carcinoma. The results of our study demonstrate that AM580 inhibits cell growth and induces RARβ mRNA expression in the Ishikawa cell line, and the expression level of RARβ in endometrial carcinoma is significantly lower than that in endometrial hyperplasia. AM580 might therefore be considered as a potential treatment for endometrial carcinoma. (Cancer Sci 2008; 99: 267–271)
The cysteine‐cluster motif of c‐Src: Its role for the heavy metal‐mediated activation of kinase
Authors: Senga Takeshi , Hasegawa Hitoki , Tanaka Miwa , Rahman Mohammad Aminur , Ito Satoko , Hamaguchi Michinari
Published: February 2008

We have previously reported that c‐Src is activated by mercuric chloride (HgCl2). We investigated the mechanism of this activation and found that in vitro activation of c‐Src by HgCl2 did not require tyrosine residues at 416 and 527. Both SH2 and SH3 domains of c‐Src were dispensable for the activation by HgCl2. In contrast, iodoacetoamide (IAA) that binds to thiol side chain of cysteine blocked the activation of c‐Src by HgCl2. To obtain more clues, each cysteine residue of c‐Src was replaced with alanine. Of six cysteine residues in the kinase domain of c‐Src, Cys483 and Cys498 located in the C‐terminal portion as a cysteine‐cluster (CC) motif were critical for the activation. In addition, other Src family kinases, Yes and Lyn, were activated by treatment with HgCl2, and cysteine residues, especially those correspond to Cys498 of Src in the CC motif of these kinases, were also required for the activation of the kinases by HgCl2. In addition to these observations, treatment of cells with HgCl2 dramatically activated the wild‐type c‐Src, whereas it could not activate the mutant form of Src with a substitution of Cys498. Taken together, our results disclose that cysteine residues in the CC motif of c‐Src, Cys483 and Cys498, act as a module for the activation of the kinase by a heavy metal compound, mercuric chloride. (Cancer Sci 2008; 99: 571–575)
Occurrence of mutations in the epidermal growth factor receptor gene in X‐ray‐induced rat lung tumors
Authors: Kitahashi Tsukasa , Takahashi Mami , Yamada Yutaka , Oghiso Yoichi , Yokohira Masanao , Imaida Katsumi , Tsutsumi Masahiro , Takasuka Nobuo , Sugimura Takashi , Wakabayashi Keiji
Published: February 2008

Epidermal growth factor receptor (EGFR) gene alterations have been found in human lung cancers. However, there is no information on the factors inducing EGFR mutations. In rodents, K‐ras mutations are frequently found in many lung carcinogenesis models, but hitherto, Egfr mutations have not been reported. Their presence was therefore investigated in representative lung carcinogenesis models with 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK), N‐nitrosobis(2‐hydroxypropyl)amine (BHP), 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline (MeIQx) and ethyl carbamate (urethane), as well as X‐ray irradiation. With the chemical carcinogenesis models, no mutations were detected in Egfr, which is in clear contrast to the high rates observed in either codon 12 or 61 of K‐ras (21/23 of the lung tumors induced with NNK, 4/5 with MeIQx, 1/4 with urethane and 7/18 with BHP). However, in the X‐ray‐induced lung tumors, Egfr mutations with amino acid substitution were observed in exons 18 and 21 (4/12, 33%), but no activating mutation of K‐ras was detected. In addition, one and four silent mutations were identified in K‐ras (exon 1) and Egfr (exons 18, 20 and 21), respectively. Most mutations in both Egfr and K‐ras were G/C→A/T transitions (7/8, 88% and 31/34, 91%, respectively). Although, the mutational patterns in equivalent human lesions were not completely coincident, this first report of Egfr mutations in an experimental lung tumor model suggests that X‐rays or other factors producing oxygen radicals could cause EGFR mutations in some proportion of lung cancers in humans. (Cancer Sci 2008; 99: 241–245)
The natural course of cannabis use, abuse and dependence during the first decades of life
Authors: Perkonigg Axel , Goodwin Renee D. , Fiedler Agnes , Behrendt Silke , Beesdo Katja , Lieb Roselind , Wittchen Hans‐Ulrich
Published: February 2008

Aims  There has been little available information on the long‐term natural course, persistence and remission of cannabis use, abuse and dependence. The current study estimated rates and risk factors associated with stability and variation in cannabis use patterns, cannabis abuse and cannabis dependence in a community sample over a 10‐year period.

Design, setting and participants  Prospective longitudinal, epidemiological study with a 4‐ and 10‐year follow‐up of a community sample (n = 3021) aged 14–24 years at baseline in Munich, Germany.

Measurements  Cannabis use, abuse and dependence and associated risk factors were assessed by face‐to‐face interviews using the Munich Composite International Diagnostic Interview.

Findings  At baseline, one‐third of the sample (34.2%) had used cannabis at least once. The cumulative incidence of cannabis use 10 years later was 50.7%. Fifty‐six per cent of all repeated users (five times or more) at baseline reported cannabis use at 4‐year follow‐up. Ten years later, this proportion had decreased slightly to only 46.3%. Repeated (five times or more) users were almost three times more likely to report repeated use at 10‐year follow up (OR = 2.8, 95% CI = 1.6–4.7), compared with those who had used cannabis fewer times. Peer use of cannabis, life‐events and alcohol dependence also predicted use of cannabis at 10‐year follow‐up.

Conclusions  Among youth who have used cannabis repeatedly (five times or more) cannabis use is fairly stable and rates of remission relatively low until age 34 yeras. Patterns of progression suggest that early targeted preventive measures should delay first use and reduce the number of experiences using cannabis, as these factors appear critical in progression to persistent cannabis use and cannabis dependence.
Driving under the influence of cannabis: a 10‐year study of age and gender differences in the concentrations of tetrahydrocannabinol in blood
Authors: Jones Alan W. , Holmgren Anita , Kugelberg Fredrik C.
Published: February 2008

Background  Δ9‐Tetrahydrocannabinol (THC) is the major psychoactive constituent of cannabis and its various preparations. Increasing use of cannabis for recreational purposes has created a problem for road‐traffic safety. This paper compares age, gender and the concentrations of THC in blood of individuals apprehended for driving under the influence of drugs (DUID) in Sweden, where a zero‐tolerance law operates.

Measurements  Specimens of blood or urine were subjected to a broad screening analysis by enzyme immunoassay methods. THC positives were verified by analysis of blood by gas chromatography‐mass spectrometry (GC‐MS) with a deuterium‐labelled internal standard (d3‐THC). All toxicology results were entered into a database (TOXBASE) along with the age and gender of apprehended drivers.

Findings  Over a 10‐year period (1995–2004), between 18% and 30% of all DUID suspects had measurable amounts of THC in their blood (> 0.3 ng/ml) either alone or together with other drugs. The mean age [± standard deviation (SD)] of cannabis users was 33 ± 9.4 years (range 15–66 years), with a strong predominance of men (94%, P < 0.001). The frequency distribution of THC concentrations (n = 8794) was skewed markedly to the right with mean, median and highest values of 2.1 ng/ml, 1.0 ng/ml and 67 ng/ml, respectively. The THC concentration was less than 1.0 ng/ml in 43% of cases and below 2.0 ng/ml in 61% of cases. The age of offenders was not correlated with the concentration of THC in blood (r = −0.027, P > 0.05). THC concentrations in blood were higher when this was the only psychoactive substance present (n = 1276); mean 3.6 ng/ml, median 2.0 ng/ml compared with multi‐drug users; mean 1.8 ng/ml, median 1.0 ng/ml (P < 0.001). In cases with THC as the only drug present the concentration was less than 1.0 ng/ml in 26% and below 2.0 ng/ml in 41% of cases. The high prevalence of men, the average age and the concentrations of THC in blood were similar in users of illicit drugs (non‐traffic cases).

Conclusions  The concentration of THC in blood at the time of driving is probably a great deal higher than at the time of sampling (30–90 minutes later). The notion of enacting science‐based concentration limits of THC in blood (e.g. 3–5 ng/ml), as discussed in some quarters, would result in many individuals evading prosecution. Zero‐tolerance or limit of quantitation laws are a much more pragmatic way to enforce DUID legislation.
Testing mechanisms of action for intensive case management
Authors: Morgenstern Jon , Blanchard Kimberly A. , Kahler Christopher , Barbosa Kirsten M. , McCrady Barbara S. , McVeigh Katharine H.
Published: February 2008

Aim  This study identified factors that predict, mediate or moderate the effects of intensive case management (ICM) on longer‐term drug abstinence outcomes in women on welfare.

Design  In a parent study women were assigned randomly to usual care (UC) or intensive case manangement (ICM). Treatment was provided for 12 weeks and follow‐up continued for 15 months after study intake. A set of hypothesized mediators was assessed at month 3 and a rigorous four‐step mediational model was tested using outcomes in months 4–15.

Participants  Participants were 302 drug‐dependent women applying and eligible for federal welfare and not currently in drug abuse treatment.

Interventions  ICM provided intensive treatment engagement including voucher incentives for treatment attendance and case management services; UC provided primarily referral to community treatment programs.

Measurement  Substance use outcomes were assessed using the time‐line follow‐back interview and confirmed using biological and collateral measures.

Findings  Participants in ICM had more case manager contacts, better treatment engagement and more self‐help attendance than did those in UC. Each of these variables predicted, and was shown to be a mediator of outcome, but case management contact was an especially robust mediator. Further, ICM effects were strongest for those who attended treatment least. Contrary to prediction, greater psychopathology and environmental stressors did not predict worse outcomes.

Conclusions  Findings suggest that case management is an active intervention that may both facilitate and substitute for formal drug abuse treatment.
Active ingredients of substance use‐focused self‐help groups
Authors: Moos Rudolf H.
Published: February 2008

Aims and methods  This paper provides an overview of some of the probable active ingredients of self‐help groups in light of four related theories that identify common social processes that appear to underlie effective psychosocial treatments for and continuing remission from these disorders.

Results  Social control theory specifies active ingredients such as bonding, goal direction and structure; social learning theory specifies the importance of norms and role models, behavioral economics and behavioral choice theory emphasizes involvement in rewarding activities other than substance use, and stress and coping theory highlights building self‐efficacy and effective coping skills. A review of existing studies suggests that the emphasis on these active ingredients probably underlies some aspects of the effectiveness of self‐help groups.

Conclusions  Several issues that need to be addressed to enhance understanding of the active ingredients of action of self‐help groups are discussed, including consideration of indices of Alcoholics Anonymous (AA) affiliation as active ingredients, identification of personal characteristics that may moderate the influence of active ingredients on substance use outcomes, examination of whether active ingredients of self‐help groups, can amplify or compensate for treatment, identification of potential detrimental effects of involvement in self‐help groups and focusing on the link between active ingredients of self‐help groups and other aspects of the overall recovery milieu, such as the family and social networks.
Deficient RPS19 protein production induces cell cycle arrest in erythroid progenitor cells
Authors: Kuramitsu Madoka , Hamaguchi Isao , Takuo Mizukami , Masumi Atsuko , Momose Haruka , Takizawa Kazuya , Mochizuki Masayo , Naito Seishirou , Yamaguchi Kazunari
Published: February 2008

The gene encoding ribosomal protein S19 (RPS19) is one of the responsible genes for Diamond‐Blackfan anaemia (DBA), a congenital erythroblastopenia. Although haplo‐insufficiency of RPS19 has been suggested to be the onset mechanism underlying the pathogenesis of DBA, the sequential mechanism has not been elucidated. In order to analyse the consequences of the missense mutation of RPS19 specific for DBA patients, we made mutated RPS19 expression vectors. Twelve C‐terminally Flag‐tagged missense mutants were exogenously expressed from retroviral vectors and analysed by Western blot analysis and flow cytometry. When these 12 mutants were expressed in the erythro‐leukaemic cell lines K562 and human bone marrow CD34+ cells, almost all of the mutant proteins (except for G120R) were unstable, and the levels of mutated RPS19 protein were significantly low. To address the effect of deficient RPS19 expression on cell proliferation, RPS19 was downregulated by siRNA. Repressive expression of RPS19 in human CD34+ cells produced an elevated number of cells at G0 and induced erythroid progenitor‐specific defects in BM cells. These results suggest that abnormal ribosomal biogenesis causes inadequate cell cycle arrest in haematopoietic progenitors, and that, subsequently, erythroid progenitors are specifically hampered. These in vitro phenotypes of genetically manipulated CD34+ cells mimic DBA pathogenesis.
Paths through the phytochrome network
Authors: JOSSE EVE‐MARIE , FOREMAN JULIA , HALLIDAY KAREN J.
Published: February 2008

Since the discovery of the physical interaction between phytochrome B and the basic helix‐loop‐helix (bHLH) transcription factor (TF) PIF3 a decade ago, plant phytochrome‐signalling research has largely focused on understanding the mechanisms through which phytochromes and members of this bHLH family signal. This concerted effort has revealed how phytochrome and bHLH TF control gene expression and plant growth, and has assigned precise roles to a number of genes in the PIF3‐like bHLH TF clade. This work has focused largely on cell autonomous signalling events; however, to synchronize plant growth and developmental events at the tissue and organ level, temporal and spatial signal integration is crucial. This review brings together current knowledge of phytochrome signalling through phytochrome‐interacting factors (PIFs)/phytochrome‐interacting factor‐like (PILs), and it evaluates the current evidence for cross‐tissue signal integration.
Nonlinear broad band dynamics are less complex in major depression
Authors: Boettger Silke , Hoyer Dirk , Falkenhahn Katrin , Kaatz Martin , Yeragani Vikram K , Bär Karl‐Jürgen
Published: February 2008

Objectives:  Cardiac mortality is known to be increased in depressive patients. However, the underlying mechanisms remain elusive to date. Decreased heart rate variability (HRV) has been discussed as contributing to increased cardiac mortality, but studies examining patients suffering from major depressive disorder (MDD) have revealed inconsistent results. This study aimed to investigate long‐term and broad band parameters of heart rate regulation in MDD, which have been shown to be more sensitive for the assessment of autonomic dysfunction.

Methods:  A total of 18 non‐medicated patients suffering from MDD and 18 matched control subjects without cardiac disease were recruited and 24‐h ambulatory electrocardiograms were recorded. Data were recorded during three distinct time intervals linear and nonlinear parameters as well as autonomic information flow (AIF) were calculated.

Results:  The power law slope was significantly reduced in the patient group for all intervals investigated and correlated with symptom severity, whereas standard deviation of the 5‐min NN intervals (SDANN) and area under the AIF curve (INTNN) showed significant differences between groups in the morning hours only. Analysis of standard HRV parameters in the time and frequency domain revealed no significant differences between groups.

Conclusions:  The evidence for decreased complexity of cardiac regulation in depressed patients presented here might be useful as an indicator of the increased cardiac mortality known in depression, especially since these parameters are capable of predicting cardiac mortality in other diseases. The importance of these parameters for patients at risk should be evaluated in future prospective studies.
Responses of stored‐product Anobiidae to pheromone lures and plant‐derived volatiles
Authors: Mahroof R. M. , Phillips T. W.
Published: February 2008

Experiments were conducted in different locations to investigate responses of adult Stegobium paniceum and Lasioderma serricorne (Col., Anobiidae) to different commercially available or prototype fabrications of their female‐produced sex pheromones. The results showed that the number of S. paniceum captured in traps baited with the commercially available lures was significantly higher than those captured in traps baited with the prototype stegobinone lures. The three commercially available brands of serricornin lures investigated were equally effective in capturing L. serricorne. In a related study, we conducted a 9‐week trapping experiment to determine if responses of L. serricorne to serricornin can be enhanced by the presence of host plant odours. Traps were baited with serricornin alone, serricornin plus dried red chilli (Capsicum frutescens L.) or red chilli alone. The results showed that the number of beetles captured in traps baited with a combination of serricornin and chilli volatiles were significantly higher than in traps baited with pheromone or chilli volatiles alone, indicating that potential exist for improved monitoring or mass trapping of L. serricorne by combining pheromone with plant‐derived volatiles present in Capsicum spp.
The dissection of risk: a conceptual analysis
Authors: O’Byrne Patrick
Published: February 2008

Recently, patient safety has gained popularity in the nursing literature. While this topic is used extensively and has been analyzed thoroughly, some of the concepts upon which it relies, such as risk, have remained undertheorized. In fact, despite its considerable use, the term ‘risk’ has been largely assumed to be inherently neutral — meaning that its definition and discovery is seen as objective and impartial, and that risk avoidance is natural and logical. Such an oversight in evaluation requires that the concept of risk be thoroughly analyzed as it relates to nursing practices, particularly in relation to those practices surrounding bio‐political nursing care, such as public health, as well as other more trendy nursing topics, such as patient safety. Thus, this paper applies the Evolutionary Model of concept analysis to explore ‘risk’, and expose it as one mechanism of maintaining prescribed/ proscribed social practices. Thereby, an analysis of risk results in the definitions and roles of the discipline and profession of nursing expanding from solely being dedicated to patient care, to include, in addition, its functions as a governmental body that unwittingly maintains hegemonic infrastructures.