bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns and consequences of differential vascular sectoriality in 18 temperate tree and shrub species
Authors: ZANNE A. E. , SWEENEY K. , SHARMA M. , ORIANS C. M.
Published: April 2006

Resource delivery within plants depends on supply pathways. Some species have relatively constrained (sectored) vascular connections, while others have relatively unconstrained (integrated) vascular connections.

In this study, patterns of vascular hydraulic sectoriality, anatomy and ecological tolerance were examined for 18 Northern Hemisphere temperate woody species growing at Arnold Arboretum, Jamaica Plain, MA, USA. A hydraulic technique was used to measure axial and tangential conductivity on branch segments. From a ratio of these values, a sectoriality index was calculated.

Species that were more hydraulically sectored had greater vessel size, variation in vessel area and tangential nearest‐neighbour distance, as well as lower vessel density, than did integrated species.

Ecologically, higher tolerance to drought and wind was correlated with being sectored, while higher tolerance to flood and shade was correlated with being integrated.

These results suggest that sectored species should be especially prominent in xeric environments where sectoriality may reduce embolism spread by minimizing vessel‐to‐vessel contact and pitting, and integrated species should be especially prominent when resources are spatially patchy or heterogeneous.
Mineral control of organic carbon mineralization in a range of temperate conifer forest soils
Authors: RASMUSSEN CRAIG , SOUTHARD RANDAL J. , HORWATH WILLIAM R.
Published: April 2006

Coupled climate–ecosystem models predict significant alteration of temperate forest biome distribution in response to climate warming. Temperate forest biomes contain approximately 10% of global soil carbon (C) stocks and therefore any change in their distribution may have significant impacts on terrestrial C budgets. Using the Sierra Nevada as a model system for temperate forest soils, we examined the effects of temperature and soil mineralogy on soil C mineralization. We incubated soils from three conifer biomes dominated by ponderosa pine (PP), white fir (WF), and red fir (RF) tree species, on granite (GR), basalt (BS), and andesite (AN) parent materials, at three temperatures (12.5°C, 7.5°C, 5.0°C). AN soils were dominated by noncrystalline materials (allophane, Al‐humus complexes), GR soils by crystalline minerals (kaolinite, vermiculite), and BS soils by a mix of crystalline and noncrystalline materials. Soil C mineralization (ranging from 1.9 to 34.6 [mg C (g soil C)−1] or 0.1 to 2.3 [mg C (g soil)−1]) differed significantly between parent materials in all biomes with a general pattern of AN<BS<GR. We found significant negative relationships between Fe‐oxyhydroxides, Al‐oxyhydroxides, and Al‐humus complex content and soil C mineralization, suggesting mineral control of C mineralization. Modeled decomposition rates and mineralizable pool size increased with increasing temperature for all parent materials and biomes. Further, δ13C values of respired CO2 suggest greater decomposition of recalcitrant soil C compounds with increasing temperature, indicating a shift in primary C source utilization with temperature. Our results demonstrate that soil mineralogy moderates soil C mineralization and that soil C response to temperature includes shifts in decomposition rates, mineralizable pool size, and primary C source utilization.
Detection of prostate cancer by α‐methylacyl CoA racemase (P504S) in needle biopsy specimens previously reported as negative for malignancy
Authors: Carswell B M , Woda B A , Wang X , Li C , Dresser K , Jiang Z
Published: April 2006

Aims : To investigate the possibility of detecting small focal prostatic cancer by α‐methylacyl CoA racemase (AMACR)/P504S immunohistochemistry on needle biopsy specimens that were previously interpreted as negative for carcinoma on routine haematoxylin and eosin (H&E)‐stained sections.

Methods : Prostate needle biopsy specimens (n = 793) previously interpreted as benign prostatic tissue by conventional morphology from 239 patients with prostatic cancer diagnosed in other biopsy cores taken at the same biopsy session were stained with the P504S monoclonal antibody. If a biopsy specimen stained positively, two pathologists independently reviewed the original corresponding H&E‐stained sections to establish the malignant diagnosis.

Results : Eighty‐four of the 793 biopsy specimens showed AMACR immunoreactivity; nine of these (9/793, 1.1%) contained previously unrecognized small focal prostatic carcinoma (Gleason 6, N = 8; Gleason 8, N = 1). Six of nine (67%) carcinomas showed foamy/pseudohyperplastic (N = 3) or atrophic (N = 3) features. Additionally, five biopsy specimens (5/793, 0.6%) with positive AMACR staining that did not meet the criteria for prostatic cancer on the original H&E slides were considered to be atypia.

Conclusions : In this study, we found a 1.1% false‐negative rate for carcinoma on routine H&E‐stained sections. AMACR immunohistochemical staining has shown the ability to improve detection of small focal prostatic carcinoma that could be missed by conventional histological examination.
Rapidly advancing laying date in a seabird and the changing advantage of early reproduction
Authors: MØLLER A. P. , FLENSTED‐JENSEN E. , MARDAL W.
Published: April 2006

Bird ringing schemes have collected immense amounts of data on timing of breeding for over 100 years. These data provide an unexploited source of information on temporal change in breeding date.

We investigated changes in breeding date of the Arctic tern Sterna paradisaea Pont. in Denmark during 1929–98, using information on ringing date of young.

Mean ringing date advanced by over 18 days during 70 years, while there was no temporal change in variance in date.

Advanced mean ringing date was explained by an increase in mean temperature during April and May and an increase in North Atlantic Oscillation (NAO) index for May.

Variance in ringing date increased in years with high temperatures in April and high NAO index values in April.

There was changing temporal patterns of selection for early breeding as reflected by analyses of the difference in mean ringing date for Arctic tern young that were subsequently recorded as survivors and mean ringing date for all young. The intensity of selection on breeding date changed from favouring late breeding in the 1930s to favouring early breeding during the 1990s.

Analyses of bird ringing information for millions of offspring of hundreds of bird species deposited in national ringing schemes may provide unlimited access to long‐term time series of reproductive variables.
Consequences for host–parasitoid interactions of grazing‐dependent habitat heterogeneity
Authors: VANBERGEN A. J. , HAILS R. S. , WATT A. D. , JONES T. H.
Published: April 2006

Environmental heterogeneity can produce effects that cascade up to higher trophic levels and affect species interactions. We hypothesized that grazing‐dependent habitat heterogeneity and grazing‐independent host plant heterogeneity would influence directly and indirectly a host–parasitoid interaction in a woodland habitat.

Thistles were planted randomly in 20 birch woodlands, half of which are grazed by cattle. The abundances of two species of seed herbivore and their shared parasitoid were measured, and related to habitat and host‐plant heterogeneity.

The presence of cattle grazing created a structurally and compositionally distinct plant assemblage from the ungrazed seminatural situation. Grazing did not affect the number or dispersion of the host plant underpinning the host–parasitoid interaction.

The density of one insect herbivore, Tephritis conura, and its parasitoid Pteromalus elevatus was significantly increased by the presence of cattle; but another herbivore, Xyphosia miliaria, was unaffected. The percentage of parasitism of T. conura was increased in grazed habitat occurring at twice the rate found in ungrazed habitat.

The increase in T. conura abundance was correlated with increased species richness and cover of forbs in grazed sites. This effect of grazing‐dependent habitat variation on host insect density cascaded up to parasitoid density and percentage of parasitism. Habitat heterogeneity had a further direct, positive effect on parasitoid density and percentage of parasitism after controlling for host‐insect density.

Independent of grazing, heterogeneity in host‐plant flowering, architecture and stature further affected T. conura and its parasitoid's densities. Parasitoid density was also affected by the dispersion of the host plant.

A combination of habitat and host‐plant scale environmental heterogeneity influenced a host–parasitoid interaction indirectly and directly, providing a rare example of an anthropogenic disturbance positively affecting a tertiary trophic level. This finding highlights the need to consider not only the importance of bottom‐up effects for top‐down processes, but also the role of environmental heterogeneity arising from anthropogenic disturbance for trophic interactions such as parasitism.
Deep‐diving foraging behaviour of sperm whales (Physeter macrocephalus)
Authors: WATWOOD STEPHANIE L. , MILLER PATRICK J. O. , JOHNSON MARK , MADSEN PETER T. , TYACK PETER L.
Published: April 2006

Digital tags were used to describe diving and vocal behaviour of sperm whales during 198 complete and partial foraging dives made by 37 individual sperm whales in the Atlantic Ocean, the Gulf of Mexico and the Ligurian Sea.

The maximum depth of dive averaged by individual differed across the three regions and was 985 m (SD = 124·3), 644 m (123·4) and 827 m (60·3), respectively. An average dive cycle consisted of a 45 min (6·3) dive with a 9 min (3·0) surface interval, with no significant differences among regions. On average, whales spent greater than 72% of their time in foraging dive cycles.

Whales produced regular clicks for 81% (4·1) of a dive and 64% (14·6) of the descent phase. The occurrence of buzz vocalizations (also called ‘creaks’) as an indicator of the foraging phase of a dive showed no difference in mean prey capture attempts per dive between regions [18 buzzes/dive (7·6)]. Sperm whales descended a mean of 392 m (144) from the start of regular clicking to the first buzz, which supports the hypothesis that regular clicks function as a long‐range biosonar.

There were no significant differences in the duration of the foraging phase [28 min (6·0)] or percentage of the dive duration in the foraging phase [62% (7·3)] between the three regions, with an overall average proportion of time spent actively encountering prey during dive cycles of 0·53 (0·05). Whales maintained their time in the foraging phase by decreasing transit time for deeper foraging dives.

Similarity in foraging behaviour in the three regions and high diving efficiencies suggest that the success of sperm whales as mesopelagic predators is due in part to long‐range echolocation of deep prey patches, efficient locomotion and a large aerobic capacity during diving.
Evaluation of maximal bite force in temporomandibular disorders patients
Authors: KOGAWA E. M. , CALDERON P. S. , LAURIS J. R. P. , ARAUJO C. R. P. , CONTI P. C. R.
Published: April 2006

summary  The aim of this study was to evaluate the maximum bite force in temporomandibular disorders (TMD) patients. Two hundred women were equally divided into four groups: myogenic TMD, articular TMD, mixed TMD and control. The maximum bite force was measured in the first molar area, on both sides, in two sessions, using an IDDK (Kratos) Model digital dynamometer, adapted to oral conditions. Three‐way anova, Tukey and Pearson correlation tests were used for the statistical analysis. The level of statistical significance was given when P ≤ 0·05. The maximal bite force values were significantly higher in the control group than in the experimental ones (P = 0·00), with no significant differences between sides. Higher values were obtained in the second session (P = 0·001). Indeed, moderate negative correlation was found between age and bite force, when articular, mixed groups and all groups together were evaluated. A moderate negative correlation was also detected between TMD severity and the maximal bite force values for myogenic, mixed and all groups together. Authors concluded that the presence of masticatory muscle pain and/or TMJ inflammation can play a role in maximum bite force. The mechanisms involved in this process, however, are not well understood and deserve further investigation.
Lentiviral expression of CTLA4Ig inhibits primed xenogeneic lymphocyte proliferation and cytokine responses
Authors: Mulley William R , Wee Janet L , Christiansen Dale , Milland Julie , Ierino Francesco L. , Sandrin Mauro S.
Published: April 2006

Mulley WR, Wee JL, Christiansen D, Milland J, Ierino FL, Sandrin MS. Lentiviral expression of CTLA4Ig inhibits primed xenogeneic lymphocyte proliferation and cytokine responses. Xenotransplantation 2006; 13: 248–252. © Blackwell Munksgaard, 2006

Abstract:  Background:  Co‐stimulatory blockade is known to inhibit lymphocyte responses and to prolong allograft and xenograft survival. The present study examines the effect of transgenic expression of cytotoxic T lymphocyte‐associated molecule‐4 immunoglobulin (CTLA4Ig) by a porcine endothelial cell line (PIEC) transduced by a lentiviral vector, on primed xenogeneic T‐cell proliferative and cytokine responses.

Methods:  Splenocytes from mice primed with PIEC were used as responder cells in a secondary proliferative assay. CTLA4Ig transduced and wild‐type PIEC were used as stimulator cells. Responder cells were assayed for proliferation and cytokine production.

Results:  Proliferation was profoundly inhibited by CTLA4Ig transduced cells compared with control cells. Cytokine analysis by enzyme linked immunospot demonstrated that production of interferon‐γ, IL4 (interleukin 4) and IL10 was inhibited by CTLA4Ig transduced cells compared with control cells.

Conclusion:  CTLA4Ig inhibited primed indirect xenogeneic T‐cell proliferative and cytokine responses in vitro. Expression of immunomodulatory molecules by xenogeneic tissues has potential therapeutic applications for future xenotransplantation.
Cardiac involvement in Henoch‐Schönlein purpura
Authors: Polizzotto M. N. , Gibbs S. D. J. , Beswick W. , Seymour J. F.
Published: April 2006

Cardiac involvement is not regarded as a feature of Henoch‐Schönlein purpura (HSP). We report a patient with HSP who developed significant cardiac symptoms, which resolved with immunosuppression. We review previous cases of HSP with cardiac features, none of which showed a response to treatment, and discuss evidence that cardiac involvement is more common than recognized. The implications for investigation and treatment of this condition are discussed.
Extreme Rank Selections for Linkage Analysis of Quantitative Trait Loci Using Selected Sib‐Pairs
Authors: Zheng G. , Ghosh K. , Chen Z. , Li Z.
Published: April 2006

It is well known that linkage analysis using simple random sib‐pairs has relatively low power for detecting quantitative trait loci with small genetic effects. The power can be substantially increased by using samples selected based on their trait values. Usually, samples that are obtained by truncation selection consist of random samples from a truncated trait distribution. In this article we propose an alternative method using extreme ranks for linkage analysis with selected sib‐pairs. This approach approximates the truncation selection. With similar screening sizes and the same sample size of selected sib‐pairs, the extreme rank selection and truncation method have similar power performance, both of which are substantially more powerful than when using random sib‐pairs. Simulation results on the comparison of powers between the truncation selection and the extreme rank selection and/or random selection for linkage analysis are reported.
ADHD and delay aversion: the influence of non‐temporal stimulation on choice for delayed rewards
Authors: Antrop Inge , Stock Pieter , Verté Sylvie , Wiersema Jan Roelt , Baeyens Dieter , Roeyers Herbert
Published: April 2006

Background:  Delay aversion, the motivation to escape or avoid delay, results in preference for small immediate over large delayed rewards. Delay aversion has been proposed as one distinctive psychological process that may underlie the behavioural symptoms and cognitive deficits of attention deficit/hyperactivity disorder (ADHD). Furthermore, the delay aversion hypothesis predicts that ADHD children's preference for immediate small over large delayed rewards will be reduced when stimulation, which makes time appear to pass more quickly, is added to the delay interval. The current paper tests these predictions.

Methods:  A group of children with a diagnosis of ADHD (with or without oppositional defiant disorder (ODD)), a group with a diagnosis of high‐functioning autism (HFA), and a normal control group were compared on an experimental paradigm giving repeated choices between small immediate and large delayed rewards (Maudsley Index of Delay Aversion–MIDA) under two conditions (stimulation and no stimulation).

Results:  As predicted, ADHD children displayed a stronger preference than the HFA and control children for the small immediate rewards under the no‐stimulation condition. The ADHD children preferences were normalised under the stimulation condition with no differences between the groups. This pattern of results was the same whether the ADHD children had comorbid ODD or not.

Discussion:  The findings from the MIDA are consistent with the delay aversion hypothesis of ADHD in showing that preference for small immediate rewards over large delayed rewards is a specific feature of ADHD and that this preference can be reduced by the addition of stimulation. Further research is required to better understand the emotional and motivational mechanisms underpinning delay aversion.
The quality of cooking oil used in informal food processing in Malawi: a preliminary study
Authors: Phiri Gabriella , Mumba Peter , Mangwera Agnes
Published: April 2006

A survey was conducted in Lilongwe city urban markets in Malawi, to assess the quality of cooking oil used for frying potato chips. Purposive sampling was performed to come up with respondents who were using vegetable oils. A stratified random sampling was used to select the 32 informal food processors who were interviewed using a structured questionnaire. Oil samples were collected from the most commonly used brand of oil. Fifteen respondents were selected and these were divided into three categories of five: those who were not reusing the oil, those who were reusing the oil and those who were preparing potato chips and chicken in the same oil, for chemical analysis. The preliminary results showed that while the majority (59.4%) of the informal food processors discarded the oil after 1 day, 3.1% discarded it after 4 days and another 12.5% after 3 days. A larger proportion of the respondents (40.6%) used the leftover oils at home, 37.5% kept it in oil bottles, 3.1% kept it in plastic papers for reuse the following day. Also, most respondents (57%) indicated dark colour as the sign of oil deterioration, 29% discarded the oil after noticing foam formation while 8.2% and 6.1% said they discarded the oil after noticing a bad smell and food absorbing the oils respectively. A physical observation of the various oils showed that for most of the respondents (34%), the oils were dark brown in colour, in 22%, the oils were slightly dark brown and 16%, the oils were brown. Foam formation was noticed in 13% of the respondents. It was also noted that 91% of the respondents had not been trained or briefed of food quality and safety issues. A chemical analysis of the oils showed high values of free fatty acids (range, 0.84–1.4112 compared with 0.42 in the fresh oil) and peroxide values (range 14.7–16.6 compared with 9.0 in the fresh oil). It may be concluded that the oils being used by the informal food processors in Malawi are of poor quality and so the foods cooked in them may be a health hazard to the consumers and the processors themselves. Although this work in ongoing, it may be recommended at the outset that the health department of the city assemblies should inspect these oils for the good health of the consumers.
Microsatellite markers for an invasive tetraploid tree, Chinese tallow (Triadica sebifera)
Authors: DEWALT S. J. , SIEMANN E. , ROGERS W. E.
Published: April 2006

We present six polymorphic microsatellite loci for Chinese tallow tree (Triadica sebifera, Euphorbiaceae), which is native to East Asia and is an aggressive, invasive species in the southeastern USA, particularly along the Coastal Plain. Microsatellite loci were tested for polymorphism across a total of 79 individuals from populations across the native range of China and in introduced populations of the southeastern USA, California, Hawaii, and Australia. Across these samples, we found a high level of polymorphism, suggesting they will be useful for deducting the introduction history of this invasive species.
Characterization of di‐, tri‐ and tetranucleotide microsatellite markers with perfect repeats for Trypanosoma brucei and related species
Authors: BALMER OLIVER , PALMA CHRISTOPHER , MACLEOD ANNETTE , CACCONE ADALGISA
Published: April 2006

Trypanosoma brucei, a unicellular parasite causing human sleeping sickness and animal nagana, has a great impact on the socioeconomic environment of sub‐Saharan Africa. The dynamics of the parasite are still poorly understood. We have characterized 14 polymorphic di‐, tri‐ and tetranucleotide microsatellite loci with perfect repeats (only one motif) exhibiting between five and 16 alleles in T. brucei isolates from all over Africa and from all described subspecies. The microsatellites will be useful in addressing population genetic questions in T. brucei to better understand the population structure and spread of this important parasite.
Visual field testing with the new Humphrey Matrix: a comparison between the FDT N‐30 and Matrix N‐30‐F tests
Authors: Brusini Paolo , Salvetat Maria Letizia , Zeppieri Marco , Tosoni Claudia , Parisi Lucia , Felletti Mirella
Published: April 2006

Purpose:  To determine if the N‐30‐F test with the new Humphrey Matrix instrument is comparable to the traditional frequency‐doubling technology (FDT) N‐30 test.

Methods:  A sample of 47 eyes from 47 patients (five normal subjects, 27 with ocular hypertension and 15 with glaucoma) underwent visual field (VF) testing with standard automated perimetry, and with FDT, using the FDT N‐30 program, and the Matrix N‐30‐F program (using the same 19 tested points, full‐threshold strategy, but with an enhanced algorithm to reduce testing time). The plots, mean deviation (MD), pattern standard deviation (PSD), defect locations and test time were compared.

Results:  The agreement between the two tests was shown to be good, except for subjects with large VF defects, in which greater PSD values were observed with the FDT test, whereas the Matrix test gave a higher MD and number of abnormal test locations in the total deviation plot. A lack of agreement was also found for the number of abnormal test locations on the pattern deviation plot at any VF loss severity level. The test time for the Matrix test was significantly shorter.

Conclusion:  The FDT N‐30 and Matrix N‐30‐F tests proved to be comparable in cases of early to moderate VF defects.
Shared decision making for in‐patients with schizophrenia
Authors: Hamann J. , Langer B. , Winkler V. , Busch R. , Cohen R. , Leucht S. , Kissling W.
Published: April 2006

Objective:  Patients’ participation in treatment planning is being increasingly advocated in mental health. The model of ‘Shared Decision Making’ (SDM) is proposed as a promising method of engaging patients in medical decisions and improving health‐related outcomes. In the present study, the feasibility and effects of SDM for in‐patients with schizophrenia should be evaluated.

Method:  Randomized controlled trial comparing a SDM program with routine care (n = 107).

Results:  The intervention studied was feasible for most of the patients and did not take up more of the doctors’ time. Patients in the intervention group had a better knowledge about their disease (P = 0.01) and a higher perceived involvement in medical decisions (P = 0.03). The intervention increased the uptake of psychoeducation (P = 0.003).

Conclusion:  Sharing medical decisions with acutely ill in‐patients with schizophrenia is in many cases possible and improves important treatment patterns. This might help in destigmatizing this group of patients and improving schizophrenia‐related health outcomes.
Clinical correlates of DHEA associated with post‐traumatic stress disorder
Authors: Yehuda R. , Brand S. R. , Golier J. A. , Yang R.‐K.
Published: April 2006

Objective:  Increased plasma dehydroepiandrosterone (DHEA) and dehydroepiandrosterone‐sulfate (DHEAS) have been demonstrated in post‐traumatic stress disorder (PTSD), but the documented beneficial effects of these steroids in enhancing mood and cognition, as well as neuroprotection, suggest their presence in PTSD may be associated with defensive rather than maladaptive effects.

Method:  We, therefore, examined plasma DHEA, DHEAS, cortisol, and the DHEA/cortisol ratio in 40 male veterans with or without PTSD, and determined their relationships to PTSD symptom severity and symptom improvement.

Results:  The PTSD group showed significantly higher plasma DHEA and non‐significantly higher DHEAS levels as well as a significantly lower cortisol/DHEA ratio, controlling for age. Regression analyses demonstrated that DHEA and DHEAS levels could be predicted by symptom improvement and coping, whereas the cortisol/DHEA ratio was predicted by severity of childhood trauma and current symptom severity.

Conclusion:  That greater symptom improvement was related to DHEA levels may suggest for a role for these hormones in modulating recovery from PTSD.
EXCITED D-BRANES AND SUPERGRAVITY SOLUTIONS
Authors: ASAKAWA TSUGUHIKO , MATSUURA SO , KOBAYASHI SHINPEI
Published: April 2006

We investigate the general solution with the symmetry ISO (1, p) × SO (9-p) of Type II supergravity (the three-parameter solution) from the viewpoint of the superstring theory. We find that one of the three parameters (c1) is closely related to the "dilaton charge" and the appearance of the dilaton charge is a consequence of deformations of the boundary condition from that of the boundary state for BPS D-branes. We give three examples of the deformed D-branes by considering the tachyon condensation from systems of [Formula: see text]-branes, unstable D9-branes and unstable D-instantons to the BPS saturated D p-branes, respectively. We argue that the deformed systems are generally regarded as tachyonic and/or massive excitations of the open strings on [Formula: see text]-brane systems.
DISCUSSION ON THE CHARACTERISTICS OF THE QUANTUM TUNNELING RADIATION OF GLOBAL MONOPOLE CHARGED BLACK HOLE
Authors: QI DE-JIANG , LI HUI-LING , JIANG QING-QUAN , LIU MEN-QUAN , YANG SHU-ZHENG
Published: April 2006

Considering energy conservation, adopting KKW method, the tunneling effect of global monopole charged black hole was deeply studied. The result shows that the emission of particle on the event horizon relates to the change of Bekenstein–Hawking entropy and the spectrum is not pure thermal. Moreover, the corrections to the entropy and temperature of the black hole are presented.
INTERSECTING D-BRANE STATES DERIVED FROM THE KP THEORY
Authors: YAMAGUCHI HIRONORI , SAITO SATORU
Published: April 2006

A general scheme to find string boundary states is developed within the framework of the theory of KP hierarchy. The method is applied to calculate correlation function of intersecting D-branes and rederived from the results of our previous works as special examples. A matrix generalization of this scheme provides a method to study dynamics of coincident multi D-branes.
Efficient Estimation of Detailed Single-Neuron Models
Authors: Huys Quentin J. M. , Ahrens Misha B. , Paninski Liam
Published: April 2006

Biophysically accurate multicompartmental models of individual neurons have significantly advanced our understanding of the input–output function of single cells. These models depend on a large number of parameters that are difficult to estimate. In practice, they are often hand-tuned to match measured physiological behaviors, thus raising questions of identifiability and interpretability. We propose a statistical approach to the automatic estimation of various biologically relevant parameters, including 1) the distribution of channel densities, 2) the spatiotemporal pattern of synaptic input, and 3) axial resistances across extended dendrites. Recent experimental advances, notably in voltage-sensitive imaging, motivate us to assume access to: i) the spatiotemporal voltage signal in the dendrite and ii) an approximate description of the channel kinetics of interest. We show here that, given i and ii, parameters 1–3 can be inferred simultaneously by nonnegative linear regression; that this optimization problem possesses a unique solution and is guaranteed to converge despite the large number of parameters and their complex nonlinear interaction; and that standard optimization algorithms efficiently reach this optimum with modest computational and data requirements. We demonstrate that the method leads to accurate estimations on a wide variety of challenging model data sets that include up to about 104parameters (roughly two orders of magnitude more than previously feasible) and describe how the method gives insights into the functional interaction of groups of channels.
Neural Representation of Information Measure in the Primate Premotor Cortex
Authors: Nakamura Kiyohiko
Published: April 2006

Animals seek information to reduce their efforts to receive rewards and perform actions that enable them to gain more information. The ability of seeking information subserves higher cognition processes such as planning and reasoning. There exists limited information on how the brain measures and seeks information. In this study, I discuss results indicating that the brain quantifies information by using the information-theoretic measure. The monkeys were trained to perform saccadic eye movement to one of the visual targets. When required to choose from the targets that included varying amounts of information regarding the goal, the animals selected the most informative target. While making a choice, the neurons in the dorsal premotor cortex exhibited activity that reflected the corresponding information value. The population response of these neurons was examined using the following three measures: the information-theoretic measure, probability gain, and absolute change in beliefs. Changes in this response exhibited relatively similar proportionality to the three measures. An analysis of two intuitive conditions for information measures, decreasing monotonicity on probability and additivity between independent events, showed that only the information-theoretic measure satisfies both the conditions. These results suggest that in comparison with the other measures, the information-theoretic measure is more plausible for information measure in the brain.
Mathematical study of transport phenomena along a tuyere of the Teniente converter
Authors: San Martín J. , Gormaz R. , Conca C. , Saouri F.-Z. , Benaddi A. , Fuentes R. , Ruz P.
Published: April 2006

This paper presents a comprehensive mathematical model of
transport phenomena which occur along a tuyere of the Teniente
converter during injection of oxygen‐enriched air. Inlet pressure,
gas velocity and temperature, the dimensions of the tuyere, and
the properties of gas are the basic data. From these inputs,
temperature distribution of the refractory walls of the converter
around the tuyere as well as the velocity, pressure, and the Mach
number along the pipe can be calculated. In this model, the heat
transfer through the metal jacket of the tuyere and the refractory
lining are duly taken into account. More precisely, a mathematical
model is developed where the equations of momentum and energy of
the gas are coupled with the equations of heat transfer inside the
solid part. This new model couples a partial differential equation
in the solid part with four ordinary differential equations in
the gas flow.
Constrained regulator problem for linear uncertain systems: Control of a pH process
Authors: Mesquine Fouad , Tadeo Fernando , Benlamkadem Abdellatif
Published: April 2006

The regulator problem for linear uncertain continuous‐time systems having control constraints is considered. Necessary and sufficient conditions of positive invariance of polyhedral domains are extended to the case of continuous‐time uncertain systems. Robust constrained regulators are then derived. An application to the control of pH in a stirred tank is then presented. First, the uncertainty in the pH process is evaluated from first‐principle models, then the design of a robust constrained regulator is presented. Simulation results show that this control law is easy to implement and that robust asymptotic stability and control admissibility are guaranteed.
Why gender matters in child welfare and protection
Authors: Featherstone Brid
Published: April 2006

This article argues that the lack of a gender analysis in New Labour policy in relation to child welfare and protection has led to problematic gaps at the level of policy and service provision. It explores why the widespread mobilization of terms such as ‘parent’ and ‘child’ obscures important and persistent issues in relation to gender equity in care-giving, sexual violence and help-seeking. Whilst there is some attention being paid to the needs of fathers, including the need to involve them in service provision, this attention is tokenistic and inadequately grounded in practice realities. The valorization of the ‘new’, particularly in the context of a New Labour project grounded in using language in a very considered way, offers opportunities to consider the ‘power of language’ at the same time as it obscures the ‘language of power’. Gender is a particular casualty in such a climate.
Children (but not women) first: New Labour, child welfare and gender
Authors: Lister Ruth
Published: April 2006

The paper’s starting point is an analysis of New Labour’s agenda for children in an emergent ‘social investment state’. It provides an overview of policies for children, which simultaneously invest in children and regulate them and their parents/mothers. Although children have moved to the heart of social policy, there is some disquiet about the way they are being positioned in this brave new world of social investment. This disquiet focuses in particular on: the construction of children as ‘becomings’ rather than ‘beings’; the paid-work-focused and future-oriented model of citizenship; the relative neglect of groups of children who are not seen to represent such a good investment; and the eclipse of parents’, and in particular, mothers’ welfare. The final section sketches out how the social investment approach might be modified in the interests of children’s well-being and flourishing and with reference to principles of (gendered) social justice.
Foucault in Guantánamo: Towards an Archaeology of the Exception
Authors: Neal Andrew W.
Published: April 2006

This article offers a critique of the discourse that has emerged around the problem of ‘the exception’. ‘The exception’ is shorthand for the problem of certain events and situations, such as 9/11, being designated as ‘exceptional’ in order to legitimate exceptional policies, practices, executive measures and laws. The article terms this discourse and practice ‘exceptionalism’. It begins by identifying problems in the treatment of the exception and exceptionalism in the work of Carl Schmitt, Giorgio Agamben and securitization theorist Ole WÊver. A different theoretical approach to the problem of the exception is then offered, drawing upon Michel Foucault's early work, The Archaeology of Knowledge. The narrative focuses on the detail of Foucault's ‘archaeological’ methodology, relating it to specific problems in the political-theoretical discourse of exceptionalism. The reasons for an emphasis on ‘archaeology’ rather than Foucault's later ‘genealogical’ slant are explained. The article concludes by arguing that ‘archaeology’ – conceived as a neo-Kantian mode of critique that is discursive and historicist – is a more appropriate and less problematic method for engaging with the problem of the exception.
Estimates and Rigorous Bounds on Pore-fluid Enhanced Shear Modulus in Poroelastic Media with Hard and Soft Anisotropy
Authors: Berryman James G.
Published: April 2006

A general analysis of poroelasticity for hexagonal, tetragonal, and cubic symmetry shows that four eigenvectors are pure shear modes with no coupling to the pore-fluid mechanics. The remaining two eigenvectors are linear combinations of pure compression and uniaxial shear, both of which are coupled to the fluid mechanics. The analysis proceeds by first reducing the problem to a 2 × 2 system. The poroelastic system including both anisotropy in the solid elastic frame (i.e., with ‘hard anisotropy’), and also anisotropy of the poroelastic coefficients (the ‘soft anisotropy’) is then studied in some detail. In the presence of anisotropy and spatial heterogeneity, mechanics of the pore fluid induces shear dependence on fluid bulk modulus in the overall poroelastic system. This effect is always present (though sometimes small in magnitude) in the systems studied, and can be comparatively large (up to a maximum increase of about 20%) in some porous media - including porous glass and Schuler-Cotton Valley sandstone presented here. General conclusions about poroelastic shear behavior are also related to some recently derived product formulas that determine overall shear response of these systems. Another method is also introduced based on rigorous Hashin-Shtrikman-style bounds for nonporous random polycrystals, followed by related self-consistent estimates of mineral constants for polycrystals. Then, another self-consistent estimation method is formulated for the porous case, and used to estimate drained and undrained effective poroelastic constants. These estimates are compared and contrasted with the results of the first method and a unified picture of the overall behavior is found in three computed examples for polycrystals of grains having tetragonal symmetry.
‘You Just Have to See It’: Exploring the Forms of Expert Pattern Recognition in the Development of Chemical Technology
Authors: Yli-Kauhaluoma Sari
Published: April 2006

This paper contributes to discussion on the forms of adaptive learning by exploring how chemistry professionals interact with and in different physical settings—laboratory, pilot plant, and industrial production plant—while developing new chemical technology. More particularly, the study examines how chemistry professionals analyse information in these three physical settings and how they transform this information from one physical setting necessary in a chemical scale-up process to another. The presented empirical evidence suggests that expert pattern recognition mediates learning between different physical settings. The study identifies different kinds of seeing as a particular form of this expert pattern recognition. Processing contextual knowledge through seeing helps chemistry professionals extract clues about the underlying issues and problems in specific physical settings, thus enhancing learning in and across those settings. Furthermore, this study examines formation of such expert pattern recognition.
Surface Funtionalization of Polymer Fibers by Sputter Coating
Authors: Wei Q. F. , Xu W. Z. , Ye H. , Huang F. L.
Published: April 2006

Polymer fibers are widely used in many industries, ranging from filtration, composites, tissue engineering, and electronics. The surface properties of polymer fibers are of importance in these applications. The surface properties of polymer fibers can be modified by different techniques. In this study, magnetron sputter coatings are used to generate functional nanostructures on polymer fiber surfaces. Conducting aluminum (Al) film, piezoelectric aluminum nitride (AlN) film, and ceramic film of aluminum oxide (Al2O3) are deposited onto polyethylene terephthalate (PET) fibers at low temperature. The surface topography and compositions of the funtionalized fibers are characterized by optical microscopy, scanning probe microscopy (SPM), and environmental scanning electron microscopy (ESEM). The observations by SPM reveal the different morphology of the fibers with different coatings. The examination by the ESEM equipped with a full energy dispersive X-ray (EDX) analysis indicates the change in the chemical compositions of the fiber surfaces.
Copper Oxide Impregnated Textiles with Potent Biocidal Activities
Authors: Gabbay Jeffrey , Borkow Gadi , Mishal Joseph , Magen Eli , Zatcoff Richard , Shemer-Avni Yonat
Published: April 2006

Impregnation or coating of cotton and polyester fibers with cationic copper endows them with potent broad-spectrum antibacterial, antiviral, antifungal, and antimite properties (Borkow, G. and Gabbay, J. (2004). Putting Copper into Action: Copper-impregnated Products with Potent Biocidal Activities, FASEB Jounal, 18(14): 1728-1730). This durable platform technology enables the mass production of woven and non-woven fabrics, such as sheets, pillow covers, gowns, socks, air filters, mattress covers, carpets, etc. without the need of altering any industrial procedures or machinery, but only the introduction of copper oxide-treated fibers. The biocidal properties of fabrics containing 3-10% copper-impregnated fibers are permanent, are not affected by extreme washing conditions, and do not interfere with the manipulation of the final products (e.g., color, press, etc.). In this article, the authors describe data showing that (i) antifungal socks containing 10% w/w (weight/weight) copper-impregnated fibers alleviate athlete’s foot; (ii) antimicrobial fabrics (sheets) containing 10% (w/w) copper-impregnated fibers decrease bacterial colonization in a clinical setting; and (iii) these products do not have skin-sensitizing properties or any other adverse effects. Taken together, these results demonstrate the wide preventive and curative potential of copper oxide-impregnated apparel products.
Quantitative elementary mode analysis of metabolic pathways: the example of yeast glycolysis
Authors: Schwartz Jean-Marc , Kanehisa Minoru
Published: April 2006

Background

Elementary mode analysis of metabolic pathways has proven to be a valuable tool for assessing the properties and functions of biochemical systems. However, little comprehension of how individual elementary modes are used in real cellular states has been achieved so far. A quantitative measure of fluxes carried by individual elementary modes is of great help to identify dominant metabolic processes, and to understand how these processes are redistributed in biological cells in response to changes in environmental conditions, enzyme kinetics, or chemical concentrations.

Results

Selecting a valid decomposition of a flux distribution onto a set of elementary modes is not straightforward, since there is usually an infinite number of possible such decompositions. We first show that two recently introduced decompositions are very closely related and assign the same fluxes to reversible elementary modes. Then, we show how such decompositions can be used in combination with kinetic modelling to assess the effects of changes in enzyme kinetics on the usage of individual metabolic routes, and to analyse the range of attainable states in a metabolic system. This approach is illustrated by the example of yeast glycolysis. Our results indicate that only a small subset of the space of stoichiometrically feasible steady states is actually reached by the glycolysis system, even when large variation intervals are allowed for all kinetic parameters of the model. Among eight possible elementary modes, the standard glycolytic route remains dominant in all cases, and only one other elementary mode is able to gain significant flux values in steady state.

Conclusion

These results indicate that a combination of structural and kinetic modelling significantly constrains the range of possible behaviours of a metabolic system. All elementary modes are not equal contributors to physiological cellular states, and this approach may open a direction toward a broader identification of physiologically relevant elementary modes among the very large number of stoichiometrically possible modes.
Specific age related signatures in Drosophila body parts transcriptome
Authors: Girardot Fabrice , Lasbleiz Christelle , Monnier Véronique , Tricoire Hervé
Published: April 2006

Background

During the last two decades progress in the genetics of aging in invertebrate models such as C. elegans and D. melanogaster has clearly demonstrated the existence of regulatory pathways that control the rate of aging in these organisms, such as the insulin-like pathway, the Jun kinase pathway and the Sir2 deacetylase pathway. Moreover, it was rapidly shown that some of these pathways are conserved from yeast to humans.

In parallel to genetic studies, genomic expression approches have given us significant information on the gene expression modifications that occur during aging either in wild type or long-lived mutant animals. But most of the genomic studies of invertebrate models have been performed so far on whole animals, while several recent studies in mammals have shown that the effects of aging are tissue specific.

Results

We used oligonucleotide microarrays to address the specificities of transcriptional responses in aging Drosophila in head, thorax or whole body. These fly parts are enriched in transcripts that represent different and complementary sets of genes. We present evidence for both specific and common transcriptional responses during the aging process in these tissues. About half of the genes described as downregulated with age are linked to reproduction and enriched in gonads. Greater downregulation of mitochondrial genes, activation of the JNK pathway and upregulation of proteasome subunits in the thorax of aged flies all suggest that muscle may be particularly sensitive to aging. Simultaneous age-related impairment of synaptic transmission gene expression is observed in fly heads. In addition, a detailed comparison with other microarray data indicates that in aged flies there are significant deviations from the canonical responses to oxidative stress and immune stress.

Conclusion

Our data demonstrates the advantages and value of regionalized and comparative analysis of gene expression in aging animals. Adding to the age-regulated genes already identified in whole animal studies, it provides lists of new regionalized genes to be studied for their functional role in the aging process. This work also emphasizes the need for such experiments to reveal in greater detail the consequences of the transcriptional modifications induced by aging regulatory pathways.