bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene frequencies of the HPA‐15 (Gov) platelet alloantigen system in Brazilians
Authors: Cardone J. D. B. , Chiba A. K. , Boturão‐Neto E. , Vieira‐Filho J. P. B. , Bordin J. O.
Published: November 2004

Summary.  The HPA‐15 (Gov) alloantigen is a biallelic co‐dominant system on human platelets, and its allele HPA‐15a and HPA‐15b differ by an A→C single nucleotide polymorphism at nucleotide 2108 of the coding sequence resulting in a Tyr682Ser substitution in the mature CD109 glycoprotein.

Employing the polymerase chain reaction‐restriction fragment length polymorphism technique, we determined the HPA‐15 gene frequencies among 276 subjects of distinct Brazilian ethnic groups including, 15 Caucasians, 15 African Brazilians, 15 Orientals, 106 Amazon Xikrin Indians, 31 Amazon Gaviões Indians and 94 blood donors.

The calculated HPA‐15a and HPA‐15b allele frequencies found in Caucasians (0.53/0.47), African Brazilians (0.57/0.43), Orientals (0.57/0.43) and Brazilian blood donors (0.52/0.48) did not differ significantly. However, the HPA‐15a and HPA‐15b gene frequencies of Xikrin Indians (0.78/0.22) were significantly different from that of all other groups (P < 0·01). The HPA‐15a/a, HPA‐15a/b and HPA‐15b/b genotype frequencies observed in Gaviões Indians were significantly different from those seen in African Brazilians (P = 0·04) and blood donors (P = 0·017).

The present data showed that the distribution of the HPA‐15 (Gov) system alleles observed among the Brazilian population is quite similar to the distributions already reported among Asian, Canadian and European populations. Moreover, the data indicated differences in the frequency of the HPA‐15 system between Amazon Indians and other distinct Brazilian ethnic groups suggesting that Amerindians would be at higher risk of HPA‐15 alloimmunization in the need of receiving blood components collected from blood donors of other ethnic groups.
A novel method for the detection of bacteria in platelet concentrates utilizing oxygen consumption as a marker for bacterial growth
Authors: McDonald C. P. , Colvin J. , Smith R. , Wilkins K. , Robbins S. , Barbara J. A. J.
Published: November 2004

Summary.  Bacterial transfusion–transmission remains a significant problem in transfusion medicine. Diversion and improved donor arm disinfection has been introduced by blood services to reduce bacterial transmissions. These interventions are not 100% effective and, therefore, there is still a requirement to screen blood donations, particularly platelet concentrates which are responsible for the majority of transmissions. Pall BDS, a novel bacterial testing system, detects the presence of bacteria in platelet concentrates by measuring the reduction in oxygen content associated with bacterial growth.

Buffy coat‐derived pooled platelet concentrates were spiked with 12 aerobic and two anaerobic organisms (one species per bag, n = 10) at 100–700 cfu mL−1. Samples were taken into Pall BDS sample pouches and incubated for 0, 24, 30 and 48 h. An initial incubation was undertaken at 35 °C for 24 h and subsequent incubation was at 22 °C. At the end of the incubation period the oxygen content in the Pall BDS pouches was measured using a gas analyser. An oxygen content less than or equal to 19·5% was deemed to be positive. Pall BDS pouches tested positive in 80, 94 and 98% units spiked with aerobic bacteria at 24, 30 and 48 h, respectively. Anaerobic bacteria were not detected by the system. Positive BDS pouches contained 106 cfu mL−1 or greater. The system was simple and easy to perform. Pall BDS has a closed sampling system which prevents exogenous contamination. This initial study indicates that the Pall BDS offers a practicable system for detecting bacteria present in leucodepleted platelet concentrates.
Valganciclovir prophylaxis in patients at high risk for the development of cytomegalovirus disease
Authors: Taber D.J. , Ashcraft E. , Baillie G.M. , Berkman S. , Rogers J. , Baliga P.K. , Rajagopalan P.R. , Lin A. , Emovon O. , Afzal F. , Chavin K.D.
Published: November 2004

Abstract: Background. Despite advances in antiviral therapies, cytomegalovirus (CMV) remains the leading opportunistic infection in the transplant population. Valganciclovir (VGC), the l‐valyl ester prodrug of ganciclovir (GCV), provides an excellent oral alternative to GCV for the prevention of CMV in transplant recipients. We investigated the use of VGC for CMV prevention in high‐risk renal and pancreas transplant recipients.

Methods. Patients at high risk for development of CMV disease were defined as either those who had donor positive, recipient‐negative serostatus (D+/R−), or those who received antilymphocyte antibody (ALA) therapy for either rejection treatment or induction. A retrospective review was conducted of all kidney and pancreas transplants performed between August 2001 and December 2003. A total of 341 transplants were performed, of which 109 received VGC, and 88 were included in this analysis.

Results. The overall incidence of CMV disease was 5.7% (5/88). All of the CMV episodes were in patients who were D+/R− (17.2% [5/29] versus 0% [0/59], P<0.001). Of these patients, all the episodes of CMV were in patients who received VGC prophylaxis for<100 days post transplant (29% [5/17] versus 0% [0/12], P=0.06). The overall incidence of leukopenia was 11% and thrombocytopenia was 7%, with the incidence between the D+/R− group and the ALA group being similar.

Conclusion. VGC is an effective agent in preventing CMV disease in kidney and pancreas transplant recipients who are at high risk for developing the disease. The optimal length of prophylaxis in D+/R− patients is still undefined, while 3 months of prophylaxis appears to be sufficient in patients who received ALA therapy.
Thermal consequences of the formation of a slab window beneath the Mid‐Cretaceous southwest Japan arc: A 2‐D numerical analysis
Authors: Okudaira Takamoto , Yoshitake Yoshiko
Published: November 2004

Abstract  The development of voluminous granitic magmatism and widespread high‐grade metamorphism in Mid‐Cretaceous southwest Japan have been explained by the subduction of a spreading ridge (Kula–Pacific or Farallon–Izanagi plate boundaries) beneath the Eurasian continent and the formation of a slab window. In the present study, the thermal consequences of the formation of a slab window beneath a continental margin are evaluated through a 2‐D numerical simulation. The model results are evaluated by comparison with the Mid‐Cretaceous geology of southwest Japan. Of particular interest are the absence of an amphibolite‐ to granulite‐facies metamorphic belt near the Wadati–Benioff plane, and significant melting of the lower crustal‐mafic rocks sufficient to form a large amount of granitic magma. Because none of the model results simultaneously satisfied these two geological interpretations, it is suggested that subduction of plate boundaries in Mid‐Cretaceous southwest Japan was not associated with the opening of a slab window. According to previous studies, and the results of the present study, two different tectonic scenarios could reasonably explain the geological interpretations for Mid‐Cretaceous southwest Japan: (i) The spreading ridge did not subduct beneath the Eurasian continent, but was located off the continental margin, implying the continuous subduction of very young oceanic lithosphere; (ii) ridge subduction beneath the continental margin occurred after active spreading had ceased. Consequently, in both tectonic scenarios, the subduction of plate boundaries at the Mid‐Cretaceous southwest Japan was not associated with a slab window, but very young (hot) oceanic lithosphere.
Heat influx and exhumation of the Shimanto accretionary complex: Miocene fission track ages from the Kii Peninsula, southwest Japan
Authors: Hasebe Noriko , Watanabe Hiroaki
Published: November 2004

Abstract  To determine how local geological events contributed to the evolution of accretionary complexes and eventual exposure of rocks with different structural levels, geochronological mapping was carried out using fission track (FT) analysis at the Kii Peninsula, southwest Japan. At this site, the original zonal structure of Cretaceous accretionary complexes parallel to the subduction zone is disturbed by the northward projection of the Shimanto  accretionary  complex.  Twenty‐six  zircon  FT ages were obtained from an area of ∼12 km in an east–west direction and ∼15 km in a north–south direction, and classified into three groups: (i) ages ∼15 Ma (range ∼10–20 Ma), which are distributed along the northwest–southeast valley; (ii) ages of ∼50 Ma in the northwest of the study area; and (iii) ages older than those in Groups 1 and 2. Based on results from eight zircon FT length distributions, the Miocene ages appear to be the result of spatial variations in heat influx and cooling after the regional exhumation of the area, as recorded by FT ages of ∼50 Ma.
Should Actuarial Risk Assessments be Used with Sex Offenders who are Intellectually Disabled?
Authors: Harris Andrew J. R. , Tough Susan
Published: November 2004

Background  Objective actuarial assessments are critical for making risk decisions, determining the necessary level of supervision and intensity of treatment (Andrews & Bonta 2003). This paper reviews the history of organized risk assessment and discusses some issues in current attitudes towards sexual offenders with intellectual disabilities.

Method  We present two risk assessment tools (RRASOR and STABLE‐2000) that appear to have practical utility with this population. Data are presented from a community sample of 81 sexual offenders who are intellectually disabled suggesting that the RRASOR may provide a useful metric of risk for this population. Dynamic risk is assessed using the STABLE‐2000. This tool, based on 16 areas empirically associated with sexual recidivism, samples the individuals’ current behaviour, skill deficits and personality factors. Change in these factors serves to flag the supervisor to changing risk levels.

Conclusions  In addressing the question of whether we should seek special risk measures normed on people with intellectually disabilities, given the current lack of alternative tools, we conclude that it is reasonable to make use of the risk assessments that have been validated on the general sex offender population.
Risk Assessment: Actuarial Prediction and Clinical Judgement of Offending Incidents and Behaviour for Intellectual Disability Services
Authors: Lindsay William R. , Beail Nigel
Published: November 2004

Background Research on prediction of violent and sexual offending behaviour has developed considerably in the mainstream criminological literature. Apart from one publication [Quinsey (2004)Offenfers with Developmental Disabilities, pp. 131–142] this has not been extended to the field of intellectual disabilities.

Methods Work on actuarial instruments, dynamic variables, clinical judgement and structured clinical judgement is reviewed.

Results A number of studies comparing actuarial instruments in terms of their predictive validity are reviewed. Relative effectiveness and applicability to intellectual disability is considered. A framework for dynamic variables is outlined and the importance of dynamic variables for inclusion in risk prediction is established. Strengths and limitations of clinical judgement are reported and the importance of reliability is noted. Finally, structured clinical judgement is reviewed in terms of the way in which it combines the other three groups of variables.

Conclusions The information regarding different methods of risk assessment is integrated with research and opinion contained in the Special Issue. Risk prediction will always be a judgement and as such there will always be errors in judgement. As clinicians, researchers and policy makers it is our duty to employ the latest research information to make predictions that are as accurate as possible. However, we must also help to promote a culture that can be tolerant of inevitable errors.
Assessment of Risk Manageability of Intellectually Disabled Sex Offenders
Authors: Boer Douglas P. , Tough Susan , Haaven James
Published: November 2004

Background There are no validated risk assessment tools for intellectually disabled (ID) sex offenders, with the exception of the work of Lindsayet al.[Journal of Applied Research in Intellectual Disabilities(2004)17: 267] regarding the prediction of risk for aggressive behaviour of ID offenders in residential settings. ID sex offenders comprise a neglected subgroup, and one that poses unique challenges and rewards for clinicians.

Methods and purpose Recent work by Tough [Tough S. (2001)Validation of Two Standard Assessments (RRASOR, 1997; STATIC‐99, 1999) on a Sample of Adult Males who are Intellectually Disabled with Significant Cognitive Deficits. Master's Thesis, University of Toronto, Toronto, ON, Canada] examined the utility of the Rapid Risk Assessment for Sexual Offence Recidivism [RRASOR;Hanson R. (1997)The Development of a Brief Actuarial Risk Scale for Sexual Offence Recidivism, User Report 97‐04. Department of the Solicitor General of Canada, Ottawa, ON, Canada.] and the Static‐99 [Hanson R. K. & Thornton D. (1999)Static‐99: Improving Actuarial Risk Assessments for Sex Offenders, User Report 99‐02. Department of the Solicitor General of Canada, Ottawa, ON, Canada] for ID sex offenders. She determined that the Static‐99 may overestimate risk in ID sex offenders and that the RRASOR seemed to be a more accurate tool for these offenders. These actuarial tools provide a ‘risk baseline’, which helps in determining treatment intensity and level of supervision, but do not provide much help in designing treatment plans or management strategies based on the needs of the individual client. Hence, all three authors have developed risk management strategies in their work with ID sex offenders based largely on dynamic factors. This work has produced the present assessment.

Outcome The present paper outlines a convergent approach which uses the information provided by static actuarial instruments and relevant dynamic factors as an introduction to the formation of a risk management strategies instrument for ID sex offenders. Thirty suggested items, split into four categories (chronic dynamic and acute dynamic for staff and environment; chronic dynamic and acute dynamic for offenders) are listed along with brief explanations of these items.
A Two‐Way Cross‐Over Bioequivalence Study Comparing Two Products of Diclofenac Sodium Suppositories in Healthy Human Volunteers
Authors: Hasan Mazen , Otoom Sameer , Najib Naji , Sallam El‐Sayed
Published: November 2004

Abstract: This report presents the results of two treatment cross‐over investigations on 20 healthy male volunteers to assess the bioequivalence of two suppository products of diclofenac sodium. The study was carried out under US Food and Drug Administration Guidelines. The two products were voltaren® (100 mg) suppository (Ciba‐Giegy), as a reference product, and Inflaban® (100 mg) suppository (The Arab Pharmaceutical Manufacturing Company, Ltd. “APM”), as a test product. Both products were administered rectally as a single dose (100 mg) separated by a one‐week wash‐out period. Following drug administration, blood samples were collected over 12 hr, and serum harvested from the blood was analyzed for diclofenac sodium using a sensitive and specific high performance liquid chromatographic assay. The results of this investigation indicated that there were no statistically significant differences between the two products in either the mean concentration‐time profiles or in the obtained pharmacokinetic parameters, including area under the serum concentration‐time curve for 12 hr (AUC0–12h), lag time between product administration and first appearance of the drug in serum (Tlag), peak serum concentration (Cmax), and time to reach this peak serum concentration (Tmax). Concerning the relative extent of absorption, assessed by the AUC ratio (Inflaban/Voltaren) for 12 hr, the average value was found to be 1.00±0.09 with a 95% confidence limits (C.L.) of 0.82–1.18. Thus, these findings clearly indicate that the two products are bioequivalent in terms of rate and extent of drug absorption.
Angiotensin II Receptor mRNA Expression and Vasoconstriction in Human Coronary Arteries: Effects of Heart Failure and Age
Authors: Wackenfors Angelica , Pantev Emil , Emilson Malin , Edvinsson Lars , Malmsjö Malin
Published: November 2004

Abstract: Angiotensin II is a potent vasoconstrictor that is implicated in the pathogenesis of hypertension, heart failure and atherosclerosis. In the present study, angiotensin II receptor mRNA expression levels were quantified by real‐time polymerase chain reaction and the vasocontractile responses to angiotensin II were characterised by in vitro pharmacology in endothelium‐denuded human coronary arteries. Angiotensin II type 1 (AT1) and type 2 (AT2) receptor mRNA expression levels were significantly down‐regulated in arteries from patients with heart failure as compared to controls. The angiotensin II‐induced vasoconstriction diminished with increasing age in patients with heart failure (r2=0.31, P<0.05). Also, the AT1 receptor mRNA expression levels decreased with increasing age in patients with heart failure (r2=0.74, P<0.05), while no such correlation could be shown in the control group (r2=0.04, P=n.s.). The AT2 receptor mRNA expression levels did not correlate with age in patients with heart failure or controls. In conclusion, the diminished angiotensin II vasoconstriction with age in heart failure patients is most likely due to a lower density of AT1 receptors and may result from a longer period of exposure to heart failure in older patients.
Transcriptional Up‐Regulation in Expression of 5‐Hydroxytryptamine2A and Transcriptional Down‐Regulation of Angiotensin II type 1 Receptors during Organ Culture of Rat Mesenteric Artery
Authors: Luo Guogang , Xu Cang‐Bao , Cao Yong‐Xiao , Edvinsson Lars
Published: November 2004

Abstract: The purpose of this study was to investigate in rat mesenteric artery if there is up‐regulation of 5‐hydroxytryptamine (5‐HT) receptors and angiotensin II receptors and the potential role of protein kinase C activation in the smooth muscle cells during organ culture. Angiotensin II, 5‐HT and potassium induced contraction of ring segments without endothelium, monitored by a sensitive in vitro pharmacology method. After the culture of the arterial ring segments for 24 hr, the concentration‐contraction curves induced by 5‐HT slightly shifted towards to the left with pEC50 from 6.64±0.11 to 6.84±0.11 and a significant increase in Emax from 147±11% to 246±15% (P<0.05), compared with that obtained in fresh segments. In contrast, the angiotensin II concentration‐contraction curve only showed a significant decrease in Emax from 99±10% to 37±8%. Specific antagonists for the 5‐HT type 2A receptors (5‐HT2A) and angiotensin II type 1 receptors (AT1) demonstrated that the contractions occurred via 5‐HT2A and AT1 receptors, respectively. Real‐time PCR revealed that the 5‐HT2A receptor mRNA was up‐regulated in parallel with the contractile response while there was a down‐regulation of AT1 receptor mRNA. Transcriptional inhibitor actinomycin D and specific protein kinase C inhibitor Ro31‐8220 demonstrated that it was a transcriptional mechanism with involvement of protein kinase C that regulated the enhanced expression of 5‐HT2A receptors in the mesenteric artery.
Transport and Bioavailability Studies of Astragaloside IV, an Active Ingredient in Radix Astragali
Authors: Gu Yongchuan , Wang Guangji , Pan Guoyu , Fawcett J. Paul , A. Jiye , Sun Jianguo
Published: November 2004

Abstract: Astragaloside IV is an important constituent of Radix Astragali, a herbal remedy widely used in traditional Chinese medicine. Radix Astragali is administered orally but little is known about the transport properties and bioavailability of astragaloside IV. In this paper we report studies of the absorption of astragaloside IV in the perfused rat intestinal model, transport and uptake in Caco‐2 cell monolayers and in vivo bioavailability in rat after an oral dose. In the perfused rat intestinal model, absorption of astragaloside IV was low from an aqueous solution but was significantly higher from a solution of Radix Astragali. Absorption was not affected by bile duct ligation. Transport through Caco‐2 cells gave a very low permeability value (mean Papp of 6.7±1.0×10−8 cm/sec.) and uptake was unaffected by P‐glycoprotein inhibitors. The absolute bioavailability of astragaloside IV in rat was 2.2%. The correlation between low permeability in vitro and poor bioavailability in vivo indicates in vitro absorption studies are useful in the evaluation of traditional Chinese medicines.
Occurrence and landscape ecology of a rare disjunct maple species,Acer pycnanthum, and comparison withAcer rubrum
Authors: Barnes Burton V , Saeki Ikuyo , Kitazawa Asako
Published: November 2004

Japanese red maple, Acer pycnanthum K. Koch, is the disjunct sister species of the red maple, Acer rubrum L. Whereas A. rubrum is one of the most widely distributed and abundant species in eastern North America, A. pycnanthum is rare in central Honshu, Japan. Although its morphological similarity to A. rubrum is well known, little is known about the sites and communities where it occurs, its natural history characteristics, sexual and asexual regeneration, and the reasons for its restricted occurrence. We located and described all known sites, totaling <18 ha, which supported populations of three or more clones. Twenty-seven of the 30 ecosystems described are remnant natural populations, which are confined to lower slopes of three river basins where wetlands have persisted and recurrently formed for millions of years due to unique geological, topographic, and soil properties. Acer pycnanthum, an obligate species of forested wetlands, occurs on diverse seepage and floodplain ecosystems that are characterized by poor drainage; acid, wet soils; high understory and ground-cover diversity, and associated rare species. The area occupied by each population is typically very small, usually <0.5 ha and often <0.2 ha. Regeneration is limited to sites with high light irradiance following disturbance. Because of the rarity of natural wetland sites, its inability to colonize upland sites occupied by dense natural vegetative cover or by planted conifers, and the encroachment of agriculture and urbanization, the occurrence of A. pycnanthum is increasingly limited. Using an ecosystem approach, conserving whole ecosystems, including their total vegetative diversity, is a high priority.Key words: biodiversity, disjunct species, landscape ecology, rare species, red maple (Acer pycnanthum, Acer rubrum), wetlands.
Sockeye salmon (Oncorhynchus nerka) nursery lake fertilization: Review and summary of results
Authors: Hyatt K D , McQueen D J , Shortreed K S , Rankin D P
Published: November 2004

We reviewed 24 sockeye salmon (Oncorhynchus nerka) nursery lake experiments that involved whole-lake fertilization with appropriate treatment and control years. We found that: 21 of 21 studies showed that fertilization was associated with increased chlorophyll a concentrations, 16 of 16 showed increased zooplankton biomasses, 16 of 16 demonstrated increased average smolt weights, and 11 of 13 showed increased smolt biomasses. Studies involving assessments of egg-to-smolt survival were rare, but all (4 of 4) showed increased survival rates. Studies involving increased smolt-to-adult survival (i.e., marine survival) were even rarer, but all (3 of 3) showed that lake fertilization and increased smolt size were associated with increased marine survival. Several fertilization studies reported problems, and some offered solutions. For instance, when whole-lake fertilization stimulated the growth of blue-green algae, fertilizer with higher nitrogen to phosphorus ratios was used to control the problem. Conversely, when high nitrogen to phosphorus ratios were associated with blooms of ungrazable diatoms, notably Rhizosolenia eriensis, reduced nitrate concentrations were recommended. To date, solutions designed to constrain the growth of both blue-green algae and Rhizosolenia blooms remain elusive. Some studies showed that when both mysids (large invertebrate planktivores) and juvenile sockeye inhabit the same lake, sockeye suffer from a competitive disadvantage and mysids consume 8090% of the available zooplanktonic food production. Similarly, a small number of studies demonstrated that competition from sticklebacks (Gasterosteus aculeatus) adversely affected sockeye growth rates, and although the problem remains unresolved, ongoing work in lakes containing kokanee (O. nerka), suggests that stocked cutthroat trout (Salmo clarki) may be capable of controlling stickleback densities through predation. Despite all of these difficulties, in almost all cases, when lakes were fertilized with various mixtures of inorganic nitrogen and phosphorus, pelagic food web bottom-up control was strong enough and predictable enough to ensure that sockeye smolt biomass increased. We conclude that sockeye nursery lake fertilization is a technique that can contribute usefully to both the enhancement and conservation of sockeye salmon populations. Key words: sockeye salmon, lake fertilization, bottom-up, aquatic food web.
Effect of the North Atlantic Oscillation on recruitment of Atlantic cod (Gadus morhua)
Authors: Brander K , Mohn R
Published: November 2004

We examine the effect of introducing an environmental factor  the North Atlantic Oscillation (NAO) index  into a stockrecruit relationship fitted to 13 North Atlantic cod (Gadus morhua) stocks and discuss the implications for management. The NAO has a significant effect on recruitment of four of the stocks (positive effect on recruitment in the North Sea, Baltic Sea, and Irish Sea; negative effect on recruitment at Iceland), and the pattern of positive and negative effects on all stocks is consistent with the geographic influence of the NAO on environmental variables. Observed variability in the NAO should be taken into account in interpreting the causes of past changes in cod stocks. The NAO index for the previous winter is available by April and thus may provide an early indication of the likely range of cod recruitment in the current year. In areas, such as the North Sea, where the effect is strong, medium- and long-term assessments of recruitment and yield of the cod stocks should consider likely future states of the NAO. The NAO can be used to represent environmental variability in stock projections and thereby provide a better basis for the estimation of risk.
The replacement of a native freshwater amphipod by an invader: roles for environmental degradation and intraguild predation
Authors: MacNeil Calum , Prenter John , Briffa Mark , Fielding Nina J , Dick Jaimie TA , Riddell Gillian E , Hatcher Melanie J , Dunn Alison M
Published: November 2004

We assessed the extent to which an invader, Gammarus pulex (Crustacea: Amphipoda), has replaced a native, Gammarus duebeni celticus, over a 13-year period in a European river system and some of the abiotic and biotic factors that could account for this. Between 1988 and 2001, 56% of mixed-species sites had become invader-only sites, whereas no mixed sites had become native only again. The native dominated areas of higher dissolved oxygen and water quality, with the reciprocal true for the invader. Field transplant experiments revealed that native survivorship was lower in areas where it had been replaced than in areas where the invader does not yet occur. In invader-only areas, native survivorship was lower than that of the invader when kept separately and lowest when both species were kept together. We also observed predation of the native by the invader. Laboratory oxygen manipulation experiments revealed that at 30% saturation, the native's survivorship was two thirds that of the invader. We conclude that decreasing water quality favours replacement of the native by the invader.
Quantifying the combined effects of attempt rate and swimming capacity on passage through velocity barriers
Authors: Castro-Santos Theodore
Published: November 2004

The ability of fish to migrate past velocity barriers results from both attempt rate and swimming capacity. Here, I formalize this relationship, providing equations for estimating the proportion of a population successfully passing a barrier over a range of distances and times. These equations take into account the cumulative effect of multiple attempts, the time required to stage those attempts, and both the distance traversed on each attempt and its variability. I apply these equations to models of white sucker (Catostomus commersoni) and walleye (Stizostedion vitreum) ascending a 23-m-long flume against flows ranging from 1.5 to 4.5 m·s1. Attempt rate varied between species, attempts, and over time and was influenced by hydraulic variables (velocity of flow and discharge). Distance of ascent was primarily influenced by flow velocity. Although swimming capacity was similar, white sucker had greater attempt rates, and consequently better passage success, than walleye. Over short distances, models for both species predict greater passage success against higher velocities owing to the associated increased attempt rate. These results highlight the importance of attraction to fish passage and the need for further investigation into the hydraulic and other environmental conditions required to simultaneously optimize both attempt rate and passage success.
Nutrient export from freshwater ecosystems by anadromous sockeye salmon (Oncorhynchus nerka)
Authors: Moore Jonathan W , Schindler Daniel E
Published: November 2004

Anadromous and semelparous salmon transport nutrients from the ocean to fresh waters when they return to spawn and die, a process inspiring a large body of research on the role of salmon-derived nutrients in coastal ecosystems. However, salmon also transport nutrients out of fresh waters when they migrate to the ocean as smolts. Using a total of 76 years of age-specific smolt-migration and adult-escapement data, we calculated the amounts of nitrogen and phosphorus that sockeye salmon (Oncorhynchus nerka) imported and exported from four major systems in Bristol Bay, Alaska. Smolts removed an average of 16% of the phosphorus and 12% of the nitrogen that their parents transported into fresh waters. The percentage of parental nutrients that smolts exported varied through time and among sites, ranging from 1% to 65% of the phosphorus and from less than 1% to 47% of the nitrogen. In systems where smolts were larger, they exported a higher percentage of nutrients. Depending on the strength of density-dependence, smolts could theoretically export more nutrients than their parents import to freshwater ecosystems at low spawning densities. Ignoring nutrient export by outgoing smolts will consistently lead to overestimation of nutrient import by Pacific salmon to freshwater ecosystems.
Genome-size evolution in fishes
Authors: Hardie David C , Hebert Paul DN
Published: November 2004

Fishes possess both the largest and smallest vertebrate genomes, but the evolutionary significance of this variation is unresolved. The present study provides new genome-size estimates for more than 500 species, with a focus on the cartilaginous and ray-finned fishes. These results confirm that genomes are smaller in ray-finned than in cartilaginous fishes, with the exception of polyploids, which account for much genome-size variation in both groups. Genome-size diversity in ray-finned fishes is not related to metabolic rate, but is positively correlated with egg diameter, suggesting linkages to the evolution of parental care. Freshwater and other eurybiotic fishes have larger genomes than their marine and stenobiotic counterparts. Although genome-size diversity among the fishes appears less clearly linked to any single biological correlate than in the birds, mammals, or amphibians, this study highlights several particularly variable taxa that are suitable for further study.
Oxygen and carbon dioxide transport during sustained exercise in diploid and triploid chinook salmon (Oncorhynchus tshawytscha)
Authors: Bernier Nicholas J , Brauner Colin J , Heath John W , Randall David J
Published: November 2004

To better understand the respiratory physiology of triploid fish, we conducted an analysis of O2and CO2transport in diploid and triploid chinook salmon (Oncorhynchus tshawytscha) swimming at 0.4 body lengths (BL)·s1, at 2.0 BL·s1, and at the critical swimming velocity (Ucrit). While O2consumption rates (MO2), MO2max, and Ucrit did not differ between ploidies, triploids had a smaller increase in MO2over the course of the swimming trial and lower arterial O2content (CaO2) values than diploids. Relative to diploids, triploids swimming at Ucrit had a reduced HbO2saturation, lower red blood cell (RBC) pH, but similar O2partial pressures (PaO2) and methemoglobin values. Overall, triploids and diploids did not differ in CaCO2, PaCO2, arterial pH, or lactate at any of the swimming speeds. Taken together, triploidy does not appear to impair CO2transport or acidbase balance during sustained exercise in chinook salmon. In contrast, our results show that triploids have a smaller O2carrying capacity than diploids. While triploids may be able to compensate for their reduced aerobic capacity under the current exercise regime, we suggest that the effects of triploidy on O2transport may contribute to the inferior performance of triploid salmon when reared under suboptimal conditions.
Evidence for limited larval dispersal in black rockfish (Sebastes melanops): implications for population structure and marine-reserve design
Authors: Miller J A , Shanks A L
Published: November 2004

Although dispersal distances of marine larvae influence gene flow and the establishment of population structure, few data on realized dispersal distances exist for marine species. We combined otolith microstructure and micro chemistry of black rockfish (Sebastes melanops) to assess their potential to provide relative estimates of larval dispersal distance. In 2001 and 2002 we measured trace elements at discrete otolith regions, representing the (i) egg/early-larval, (ii) pelagic larval, and (iii) late-larval/early-juvenile periods of fish collected at three locations 120460 km apart. Discriminant-function analyses based on geochemical signatures at each otolith region accurately grouped an average of 85% (jackknife =  67%) and 87% (jackknife = 81%) of the fish to collection location in 2001 and 2002, respectively. Age at collection ranged from 83 to 174 days and parturition dates within each site were spread over a 22- to 66-day period. Therefore, individuals within sites were not released at similar times. A probable explanation of these data is that larvae from different geographic locations did not mix during ontogeny and possibly did not disperse long distances alongshore. Larval dispersal distances may be appreciably shorter, <120 km, than previously assumed based on models of passive dispersal.
The population dynamics of Northeast Arctic cod (Gadus morhua) through two decades: an analysis based on survey data
Authors: Hjermann Dag Ø. , Stenseth Nils Chr. , Ottersen Geir
Published: November 2004

We analyse the population dynamics of Northeast Arctic cod (Gadus morhua) by applying statistical population models to 22 years of research survey data on abundance, length, and maturation. The models for abundance and individual length are selected using Akaike's information criterion (AICC). Survival of 2- to 4-year-old cod was found to be negatively related to the abundance of cod relative to its preferred prey, capelin (Mallotus villosus), likely the result of increased cannibalism from older cod when there is a lack of capelin. Growth up to age 4 decreases with abundance and increases with sea temperature and the North Atlantic Oscillation index, whereas growth from age 4 to age 8 decreases with increasing cod–capelin ratio. The statistical models were combined in a dynamic age-structured model, coupling the dynamics of abundance and body length (reproduction depends on body length, and length growth is influenced by abundance). Simulations using this model are able to recreate the main abundance patterns of each age group for 1982–2002. The model's ability to predict changes in the abundance of spawners appeared to be most limited by our ability to predict survival of 3- to 6-year-old immature cod.
RECOGNIZING NON-FLOUNDERING LOGIC PROGRAMS AND GOALS
Authors: BARBUTI ROBERTO , MARTELLI MAURIZIO
Published: November 2004

The introduction of negation in Logic Programming using the Negation as Failure Rule causes some problems regarding the completeness of the SLDNF-Resolution proof procedure. One of the causes of incompleteness arises when evaluating a non-ground negative literal. This is solved by forbidding these evaluations. Obviously, there is the possibility of having only non-ground negative literals in the goal (the floundering of the goal). There is a class of programs and goals (allowed) that has been proved to have the non-floundering property. In this paper an algorithm is proposed which recognizes a wider class of programs with this property and which is based on abstract interpretation techniques.
STRONG SEPARATIONS FOR THE BOOLEAN HIERARCHY OVER RP
Authors: BRUSCHI DANILO , JOSEPH DEBORAH , YOUNG PAUL
Published: November 2004

Recently, boolean hierarchies over NP and over RP (denoted BH and RBH respectively) have been introduced in complexity theory. They have proved particularly useful in carefully classifying natural problems which are not finely classified using more standard time and space complexity classes. In this paper we are particularly interested in the structural properties of these hierarchies and in relationships among various boolean hierarchies.

Establishing the most significant relationships between BH, RBH, and other complexity classes would imply solving some of the major open problems in complexity theory. To date the only significant relations known are: [Formula: see text], [Formula: see text] and RBH⊆BH. Essentially nothing is known about the fine structure of BH or of RBH.

In [5] an oracle X is constructed for which both BHx and RBHx have an infinite number of proper levels. Further each level of RBH is properly contained in the corresponding level of BH, and RBH is properly contained in PP. In this paper we further explore these constructions. We prove that some of these separations are “strong” separations. That is, they can be witnessed by sets that cannot be “approximated” by sets in the smaller class: the separating sets are immune to sets from the smaller class.

Specifically, we prove that the separations between RBH, BPP, PP and each level of BH, can be witnessed by immune sets.
UNIVERSAL INFORMATION SYSTEMS
Authors: DROSTE MANFRED , GÖBEL RÜDIGER
Published: November 2004

In the theory of denotational semantics of programming languages, several authors proved the existence of particular kinds of universal domains. D. Scott constructed universal information systems, which are, however, not unique up to isomorphism. Here, we use a model-theoretic technique to establish the existence and uniqueness of a universal homogeneous information system. Similar results are also obtained for canonical and for stable information systems, respectively.
A RECURRENT NEURAL NETWORK USING TRI-STATE HIDDEN NEURONS TO ORTHOGONALIZE THE MEMORY SPACE
Authors: Davenport Michael R. , Hoffmann Geoffrey W.
Published: November 2004

This paper describes a process for adding hidden neurons to a fully recurrent Hopfield neural network in such a way as to optimize the orthogonality of the memory space. The process uses the network itself, operating with a "reverse update rule" to assign optimal values to the hidden neurons for each memory. The outer product rule is used to modify synaptic strengths as each new memory is added. As in a standard Hopfield network this is a fast process because it is noniterative. Tri-state hidden neurons, initially set to zero, are used in the recovery of memories. Simulations indicate that the storage capacity of the network for uncorrelated memories, and the radius of attraction of each memory, are significantly better than those of the standard Hopfield network. The use of hidden neurons permits flexibility in the network capacity for memories of a given length. The network is able to solve second-order hetero-associative problems, as illustrated with solutions to the XOR set of associations.
VLSI DEVICES AND CIRCUITS FOR NEURAL NETWORKS
Authors: Card H. C. , Moore W. R.
Published: November 2004

This paper provides a tutorial of various VLSI approaches to synthesizing artificial neural networks as microelectronic systems. The means by which the network learns and the synaptic weights become modified is a central theme in this study. The majority of the presentation is concerned with analog circuit approaches to neurons and synapses, employing CMOS circuits. Also included is recent work towards VLSI in situ learning circuits which implement qualitative approximations to Hebbian learning with economy of transistors. An attempt is also made to anticipate relevant developments in VLSI devices which would be suited to neural networks, just as conventional MOS transistors are well suited to traditional digital computer systems.
A NEW METHOD FOR MAPPING OPTIMIZATION PROBLEMS ONTO NEURAL NETWORKS
Authors: Peterson Carsten , Söderberg Bo
Published: November 2004

A novel modified method for obtaining approximate solutions to difficult optimization problems within the neural network paradigm is presented. We consider the graph partition and the travelling salesman problems. The key new ingredient is a reduction of solution space by one dimension by using graded neurons, thereby avoiding the destructive redundancy that has plagued these problems when using straightforward neural network techniques. This approach maps the problems onto Potts glass rather than spin glass theories. A systematic prescription is given for estimating the phase transition temperatures in advance, which facilitates the choice of optimal parameters. This analysis, which is performed for both serial and synchronous updating of the mean field theory equations, makes it possible to consistently avoid chaotic behavior.

When exploring this new technique numerically we find the results very encouraging; the quality of the solutions are in parity with those obtained by using optimally tuned simulated annealing heuristics. Our numerical study, which for TSP extends to 200-city problems, exhibits an impressive level of parameter insensitivity.
THE COLLECTIVE BRAIN
Authors: Huberman Bernardo A.
Published: November 2004

Since their invention, computers have been designed, used and improved using the human mind as metaphor. The appearance of a distributed form of computation in large networks in shifting the emphasis towards social structures as a source of inspiration for the design of new systems. I suggest that a reverse strategy could prove to be useful as well. If our results are any indication of future developments, the workings of distributed computational systems could provide a flexible and controlled environment for the study of complex interactions that are seldom accessible in the natural world.
AN ARTIFICIAL NEURAL NETWORK ALGORITHM FOR DYNAMIC PROGRAMMING
Authors: Chiu Chinchuan , Maa Chia-Yiu , Shanblatt Michael A.
Published: November 2004

An artificial neural network (ANN) formulation for solving the dynamic programming problem (DPP) is presented. The DPP entails finding an optimal path from a source node to a destination node which minimizes (or maximizes) a performance measure of the problem. The optimization procedure is implemented and demonstrated using a modified Hopfield–Tank ANN. Simulations show that the ANN can provide a near-optimal solution during an elapsed time of only a few characteristic time constants of the circuit for DPPs with sizes as large as 64 stages with 64 states in each stage. An application of the proposed algorithm to an optimal control problem is presented. The proposed artificial neural network dynamic programming algorithm is attractive due to its radically improved speed over conventional techniques especially where real-time near-optimal solutions are required.
A HOLOGRAPHIC MODEL OF MEMORY, LEARNING AND EXPRESSION
Authors: Sutherland John G.
Published: November 2004

Presented is a new paradigm for artificial neural system (ANS) design. The theoretical basis employs a novel concept whereby information is represented by phase angle orientations on a Riemann plane. Central to the theory of operation is the principle of information storage and expression in the form of stimulus-response patterns. The governing equations form a nonconnectionist approach in which a very large number of analog stimulus-response patterns or associations may be superimposed or enfolded onto a single neural element. The system indicates a mechanism by which the above associations may be both encoded and expressed on one noniterative transformation. A broad analogy may be made to digital holography1 in the form of the constitutive equations and some general operating characteristics. Simulation results for the system indicate information storage capacities and effective rates of processing orders of magnitude beyond current ANS theory. Many observable characteristics are displayed by the system which suggest that the analytical method may provide insight into the information processing mechanism occurring within neurobiological systems.
CHAOTIC BEHAVIOR OF A NEURAL NETWORK WITH DYNAMICAL THRESHOLDS
Authors: Hendin O. , Horn D. , Usher M.
Published: November 2004

Models of neural networks which include dynamical thresholds can display motion in pattern space, the space of all memories. We investigate this motion in a particular model which is based on a feedback network of excitatory and inhibitory neurons. We find that small variations in the parameters of the model can lead to big qualitative changes of its behavior. We display results of closed loops and chaotic motion which turn from one to the other through intermittency. We show that the basin of attraction of a closed orbit has a fractal shape, and find that the dimension of the chaotic motion is slightly bigger than 2. The general character of the dynamics of this model is convergence to centers of attraction on short time scales and divergence on long ones.
MIXTURE STATES AND STORAGE WITH CORRELATED PATTERNS IN HOPFIELD'S MODEL
Authors: Erichsen Rubem , Theumann W. K.
Published: November 2004

The Hopfield model of associative memory with the Hebb learning rule is studied for a finite number p of correlated patterns. The storage capacity α = P/N is considered in a network with further P − p embedded uncorrelated patterns, and the corresponding phase diagrams are exhibited. Numerical simulations are carried out to discuss the retrieval quality and the basins of attraction of the network.
QUANTUM WELL OPTOELECTRONIC SWITCHING DEVICES
Authors: MILLER D.A.B.
Published: November 2004

Quantum well semiconductor structures allow small, fast, efficient optoelectronic devices such as optical modulators and switches. These are capable of logic themselves and have good potential for integration with electronic integrated circuits for parallel high speed interconnections. Devices can be made both in waveguides and two-dimensional parallel arrays. Working arrays of optical logic and memory devices have been demonstrated, to sizes as large as 2 048 elements, all externally accessible in parallel with free-space optics. This article gives an overview of the physics underlying the operation of such devices, and describes the principles of several of the device types, including self-electrooptic effect devices (SEEDs).