bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of the parameters of fish stock dynamics from catch-at-age data and indices of abundance: can natural and fishing mortality be separated?
Authors: Aanes Sondre , Engen Steinar , Sæther Bernt-Erik , Aanes Ronny
Published: September 2007

Models for fluctuations in size of fish stocks must include parameters that describe expected dynamics, as well as stochastic influences. In addition, reliable population projections also require assessments about the uncertainties in estimates of vital parameters. Here we develop an age-structured model of population dynamics based on catch-at-age data and indices of abundance in which the natural and fishing mortality are separated in a Bayesian state–space model. Markov chain Monte Carlo methods are used to fit the model to the data. The model is fitted to a data set of 19 years for Northeast Arctic cod (Gadus morhua). By simulations of the fitted model we show that the model captures the dynamical pattern of natural mortality adequately, whereas the absolute size of natural mortality is difficult to estimate. Access to long time series of high-quality data are necessary for obtaining precise estimates of all the parameters in the model, but some parameters cannot be estimated without including some prior information. Nevertheless, our model demonstrates that temporal variability in natural mortality strongly affects perceived variability in stock sizes. Thus, using estimation procedures that neglect temporal fluctuations in natural mortality may therefore give biased estimates of fluctuations in fish stock sizes.
Geometric morphometric analysis of fish scales for identifying genera, species, and local populations within the Mugilidae
Authors: Ibañez Ana L , Cowx Ian G , O'Higgins Paul
Published: September 2007

Geometric morphometric methods (GMMs) were used to determine if scale morphology can discriminate between genera, species, geographic variants, and stocks of mullet (Mugilidae). GMMs were used because they allow standard multivariate analyses while preserving information about scale shape, which is important in making biological interpretations of results. The method was tested on ctenoid scales from mullets collected from different areas of the Gulf of Mexico and Aegean Sea. Scales were submitted to generalised procrustes analysis, followed by principal components analysis of resulting shape coordinates. Principal component scores were submitted to cross-validated discriminant analysis to determine the efficacy of scale landmarks in discriminating by taxon and population. Fish scale form was least effective in discriminating populations from nearby areas, better when populations are more geographically dispersed, and best between species and genera. Scale form variations reflected previous genetic studies that differentiated congeneric Mugil cephalus and Mugil curema, which are distinct from other Mugilidae. The method is nondestructive, quick, and less costly than genetic analysis, thus allowing many individuals to be screened.
Does size matter? A cautionary experiment on overoptimism in length-based bioresource assessment
Authors: Fonseca Duane B , Sheehy Matt RJ
Published: September 2007

Recently, there has been considerable progress in the development of neurolipofuscin-based age determination methods for crustacean stock assessment. Initial applications to lobster and crab fisheries suggest some important method-related differences between conventional length-based assessment parameter estimates and those derived with the new aging technique. Here, for the first time, we aim to clarify the basis for and implications of some of these discrepancies using an experimental fishery context. We estimate von Bertalanffy growth parameters (k and l∞), longevity (tmax), total and natural mortality (Z and M, respectively), maximum sustainable relative yield-per-recruit (MSY'/R), and the exploitation rate that produces MSY'/R (EMSY'/R) for a freshwater crayfish (Pacifastacus leniusculus) population by length–frequency analysis and tag–recapture (length-increment-at-length) and compare these results with simultaneous neurolipofuscin demographic estimates. Our central finding is that the length-based approaches are largely blind to the biological reality of asymptotic postmaturational growth, with the consequence that longevity is prone to underestimation, late growth trajectories and mortality rates to inflation, and sex differences to misjudgment. This inherent bias is likely to lead to pervasive undervaluing of potential yields and overly optimistic target exploitation rates that will heighten the risk of growth and recruitment overfishing. Neurolipofuscin offers a means of identifying and overcoming this important problem.
Context-dependent responses of juvenile Atlantic salmon (Salmo salar) to forestry activities at multiple spatial scales within a river basin
Authors: Deschênes Julie , Rodríguez Marco A , Bérubé Pierre
Published: September 2007

We used classification trees and regression trees to relate the incidence and density of juvenile Atlantic salmon (Salmo salar) to forestry activities measured at four spatial scales (subbasin and 8, 2, and 0.5 km radii upstream of study sites) and environmental features in 120 stream reaches of the Cascapedia River basin, Québec, Canada. At all scales, incidence increased with reach size and accessibility to the reach from the river mainstem. Incidence declined with areal coverage of logging at all scales, but only in larger reaches. The time horizon over which logging effects were detected increased with spatial scale. At all scales, density in salmon-bearing reaches increased with accessibility. Density in more accessible reaches was negatively related to logging over the preceding 9 years at the subbasin and 8 km scales, but no effects of logging on density were detected at the 2 and 0.5 km scales. Overall, apparent effects of logging activities on salmon incidence and density were mostly negative and strong, but were both markedly scale-dependent and conditional on environmental context.
Chinook salmon (Oncorhynchus tshawytscha) — seabird covariation off central California and possible forecasting applications
Authors: Roth Jennifer E , Mills Kyra L , Sydeman William J
Published: September 2007

We evaluated covariation between Chinook salmon (Oncorhynchus tshawytscha) abundance and seabird breeding success in central California, USA, and compared potential forecasts to predictive models based on jack (2-year-old male) returns in the previous year. Stepwise regression models based on seabird breeding success in the previous year were comparable to or stronger than jack-based models. Including seabird breeding success in the current year improved the strength of the relationships. Combined approaches that included seabird and jack data further improved the models in some cases. The relationships based on seabird breeding success remained relatively strong over both shorter (1990–2004) and longer (1976–2004) time periods. Regression models based on multivariate seabird or combined seabird–jack indices were not as strong as stepwise regression models. Our results indicate that there is significant covariation in the responses of salmon and seabirds to variability in ocean conditions and that seabird data may offer an alternate way of forecasting salmon abundance in central California.
Geomorphology and stream habitat relationships with smallmouth bass (Micropterus dolomieu) abundance at multiple spatial scales in eastern Oklahoma
Authors: Dauwalter Daniel C , Splinter Dale K , Fisher William L , Marston Richard A
Published: September 2007

Fluvial geomorphic processes structure habitats important to stream fishes. We determined relationships between densities of smallmouth bass (Micropterus dolomieu) and ecoregions, watershed and reach morphology, and stream habitat in eastern Oklahoma, USA. Watershed and reach morphology were measured at 128 stream sites, and stream habitat and smallmouth bass abundance were measured in 1800 channel units. Variation in stream size, channel morphology, and substrate size constituted major physical differences among sites. Channel morphology differed among ecoregions in the largest streams. Densities of age-0 and age-1 and older smallmouth bass were approximately an order of magnitude greater in the Boston Mountains and Ozark Highlands streams than in Ouachita Mountains streams. Regression tree analysis explained less variation in age-0 (10-fold cross-validated relative error = 0.843) than in age-1 and older (relative error = 0.650) smallmouth bass densities and showed that stream size and channel-unit size were primary determinants of density. Channel morphology explained variation in densities in deep channel units of large streams, which was somewhat independent of ecoregion.
Long-term polychlorinated biphenyl elimination by three size classes of yellow perch (Perca flavescens)
Authors: Paterson Gord , Drouillard Ken G , Leadley Todd A , Haffner G Doug
Published: September 2007

Three size classes of yellow perch (Perca flavescens) were dosed with a polychlorinated biphenyl (PCB) mixture and allowed to depurate the chemicals over 1 year while reared in 5000 L experimental tanks maintained under ambient environmental conditions. During the summer, PCB elimination rate constants for small perch (mean  =  10.1 g) averaged approximately three times those calculated for medium-sized individuals (mean  =  45.9 g) and four times those determined for the largest fish (mean  =  86.7 g). Significant differences in PCB congener depuration were observed among the three size classes with negligible elimination of congeners of the octanol-water partition coefficient (log Kow) > 6.5 occurring for the two larger size classes. Over the winter months, medium and large perch eliminated PCB 19 only, the least hydrophobic congener, with no elimination of PCBs of log Kow > 5.8 observed for the smallest individuals. An increase in lipid-normalized PCB concentrations was observed during the overwinter period because of the depletion of lipids as an energetic reserve. For medium and large perch, this increase was sufficient to overwhelm any elimination achieved during the spring and summer seasons. These results demonstrate that the allometry of species bioenergetics and seasonal temperature fluctuations are responsible for the degree of chemical biomagnification observed in aquatic food webs.
Evidence for greater reproductive output per unit area in areas protected from fishing
Authors: Kaiser Michel J , Blyth-Skyrme Robert E , Hart Paul JB , Edwards-Jones Gareth , Palmer David
Published: September 2007

Marine protected areas are advocated as an essential management tool to ensure the sustainable use of marine resources by providing insurance against over-exploitation and through the provision of refuge for a large biomass of sexually mature adults. Using a unique fishing gear-restriction, voluntary management system as a large-scale experiment, we found that adult scallops (Pecten maximus) within areas protected from towed bottom-fishing gear had heavier adductor muscle tissue and gonads that were 19%–24% heavier than those of scallops in fished areas, while other body and age characteristics were similar in both areas. The scallops within the protected area also occurred at a much higher abundance than adjacent, chronically fished (× 12.83) and wider commercially exploited (× 2.18) areas. These results provide evidence that the use of towed bottom-fishing gear can further exacerbate the effects of overfishing through the suppression of the reproductive potential of individuals of similar body size. These findings underline the utility of using closed areas as tools for fisheries conservation of sedentary species of commercial importance.
The influence of family-correlated survival onNb/Nfor progeny from integrated multi- and single-generation hatchery stocks of coho salmon (Oncorhynchus kisutch)
Authors: Moyer G R , Blouin M S , Banks M A
Published: September 2007

There exist surprisingly few data on the final variance and mean of family sizes for hatchery-born fish at the adult stage. Thus, it is difficult to predict, for a conservation hatchery operation that minimizes the variance in progeny number, how much lower the true effective population size (Ne) of a cohort of hatchery-born adults will be than Nepredicted simply by the number of parents that produced them. We used parentage analysis to estimate the survival and Nefor two integrated stocks of hatchery coho salmon (Oncorhynchus kisutch). One hatchery is a multigeneration stock obtained by spawning 70% hatchery with 30% naturally reproducing fish, whereas the second is a single-generation stock derived from naturally reproducing coho. There was no significant difference in average overall survival between stocks, but observed Newas significantly less than expected for each stock. Family-correlated survival contributed to roughly a 20% reduction in Neover the freshwater and marine life stages. This reduction is similar to previous estimates and suggests a value that can be used when estimating the effective number of hatchery parents in applications of the Ryman–Laikre formula (at least for programs such as ours that attempt to equalize sex ratios and family sizes).
Seasonal changes of dissolved organic carbon photo-oxidation rates in a tropical humic lagoon: the role of rainfall as a major regulator
Authors: Suhett Albert Luiz , Amado André Megali , Enrich-Prast Alex , Esteves Francisco de Assis , Farjalla Vinicius Fortes
Published: September 2007

In this paper, we report the seasonal variation of photo-oxidation rates in a tropical humic lagoon and its relation to annual rainfall regime. Photo-oxidation rates ranged from 8.96 to 415.06 µmol C·L–1·day–1, being higher in the beginning to middle of the rainy season and declining throughout the year. Although dissolved organic carbon (DOC) concentration, water color, and sunlight incidence were generally higher in the rainy season, photo-oxidation rates were not significantly related to any of these parameters. Photo-oxidation seems to be influenced mainly by changes in DOC photoreactivity, which was up to threefold higher early in the rainy season, when inputs of fresh allochthonous DOC take place. In the following months, in addition to being continuously degraded by sunlight, DOC is also removed from the water column by processes such as microbial degradation and sedimentation, leading to a decline in DOC concentration and photoreactivity throughout the year until the next rainy season. Thus, the dynamics of DOC inputs caused by the rainfall regime in Comprida Lagoon lead to a yearly pulse of DOC photoreactivity and photo-oxidation rates. We believe this pulse model also fits other aquatic ecosystems subject to similar seasonal inputs of allochthonous DOC, although rainfall would not necessarily be the driving factor.
Increased insulin sensitivity and maintenance of glucose utilization rates in fetal sheep with placental insufficiency and intrauterine growth restriction
Authors: Limesand Sean W. , Rozance Paul J. , Smith Danielle , Hay William W.
Published: September 2007

In this study we determined body weight-specific fetal (umbilical) glucose uptake (UGU), utilization (GUR), and production rates (GPR) and insulin action in intrauterine growth-restricted (IUGR) fetal sheep. During basal conditions, UGU from the placenta was 33% lower in IUGR fetuses, but GUR was not different between IUGR and control fetuses. The difference between glucose utilization and UGU rates in the IUGR fetuses demonstrated the presence and rate of fetal GPR (41% of GUR). The mRNA concentrations of the gluconeogenic enzymes glucose-6-phophatase and PEPCK were higher in the livers of IUGR fetuses, perhaps in response to CREB activation, as phosphorylated CREB/total CREB was increased 4.2-fold. A hyperglycemic clamp resulted in similar rates of glucose uptake and utilization in IUGR and control fetuses. The nearly identical GURs in IUGR and control fetuses at both basal and high glucose concentrations occurred at mean plasma insulin concentrations in the IUGR fetuses that were ∼70% lower than controls, indicating increased insulin sensitivity. Furthermore, under basal conditions, hepatic glycogen content was similar, skeletal muscle glycogen was increased 2.2-fold, the fraction of fetal GUR that was oxidized was 32% lower, and GLUT1 and GLUT4 concentrations in liver and skeletal muscle were the same in IUGR fetuses compared with controls. These results indicate that insulin-responsive fetal tissues (liver and skeletal muscle) adapt to the hypoglycemic-hypoinsulinemic IUGR environment with mechanisms that promote glucose utilization, particularly for glucose storage, including increased insulin action, glucose production, shunting of glucose utilization to glycogen production, and maintenance of glucose transporter concentrations.
Dynamics of insulin sensitivity, β-cell function, and β-cell mass during the development of diabetes in fa/fa rats
Authors: Topp Brian G. , Atkinson Laura L. , Finegood Diane T.
Published: September 2007

Both male Zucker Fatty (mZF) and lower-fat-fed female Zucker diabetic fatty (LF-fZDF) rats are obese but remain normoglycemic. Male ZDF (mZDF) and high-fat-fed female ZDF rats (HF-fZDF) are also obese but develop diabetes between 7 and 10 wk of age. Although these models have been well studied, the mechanisms governing the adaptations to obesity in the normoglycemic animals, and the failure of adaptation in the animals that develop diabetes, remain unclear. Here we use quantitative morphometry and our recently developed coupled β-cell mass (βm), insulin, and glucose model to elucidate the dynamics of insulin sensitivity (SI), β-cell secretory capacity (βsc), and βm in these four animal models. Both groups that remained normoglycemic with increasing obesity (mZF, LF-fZDF) exhibited increased βm and constant βsc in response to a falling SI. In rats that developed hyperglycemia (mZDF, HF-fZDF), there was a greater reduction in SI and slower expansion of βm, with constant βsc. βsc decreased after glucose levels rose above 20 mM. Taken together, these data suggest that excessive insulin resistance and insufficient β m adaptation play a primary role in the pathogenesis of diabetes.
A Concept for Extending the Applicability of Constraint-Induced Movement Therapy through Motor Cortex Activity Feedback Using a Neural Prosthesis
Authors: Ward Tomas E. , Soraghan Christopher J. , Matthews Fiachra , Markham Charles
Published: September 2007

This paper describes a concept for the extension of constraint-induced movement therapy (CIMT) through the use of feedback of primary motor cortex activity. CIMT requires residual movement to act as a source of feedback to the patient, thus preventing its application to those with no perceptible movement. It is proposed in this paper that it is possible to provide feedback of the motor cortex effort to the patient by measurement with near infrared spectroscopy (NIRS). Significant changes in such effort may be used to drive rehabilitative robotic actuators, for example. This may provide a possible avenue for extending CIMT to patients hitherto excluded as a result of severity of condition. In support of such a paradigm, this paper details the current status of CIMT and related attempts to extend rehabilitation therapy through the application of technology. An introduction to the relevant haemodynamics is given including a description of the basic technology behind a suitable NIRS system. An illustration of the proposed therapy is described using a simple NIRS system driving a robotic arm during simple upper-limb unilateral isometric contraction exercises with healthy subjects.
Video Transmission over MIMO-OFDM System: MDC and Space-Time Coding-Based Approaches
Authors: Zheng Haifeng , Ru Congchong , Chen Chang Wen , Yu Lun
Published: September 2007

MIMO-OFDM is a promising technique for the broadband wireless communication system. In this paper, we propose a novel scheme that integrates multiple-description coding (MDC), error-resilient video coding, and unequal error protection strategy with hybrid space-time coding structure for robust video transmission over MIMO-OFDM system. The proposed MDC coder generates multiple bitstreams of equal importance which are very suitable for multiple-antennas system. Furthermore, according to the contribution to the reconstructed video quality, we apply unequal error protection strategy using BLAST and STBC space-time codes for each video bitstream. Experimental results have demonstrated that the proposed scheme can be an excellent alternative to achieve desired tradeoff between the reconstructed video quality and the transmission efficiency.
A Semisupervised Support Vector Machines Algorithm for BCI Systems
Authors: Qin Jianzhao , Li Yuanqing , Sun Wei
Published: September 2007

As an emerging technology, brain-computer interfaces (BCIs) bring us new communication interfaces which translate brain activities into control signals for devices like computers, robots, and so forth. In this study, we propose a semisupervised support vector machine (SVM) algorithm for brain-computer interface (BCI) systems, aiming at reducing the time-consuming training process. In this algorithm, we apply a semisupervised SVM for translating the features extracted from the electrical recordings of brain into control signals. This SVM classifier is built from a small labeled data set and a large unlabeled data set. Meanwhile, to reduce the time for training semisupervised SVM, we propose a batch-mode incremental learning method, which can also be easily applied to the online BCI systems. Additionally, it is suggested in many studies that common spatial pattern (CSP) is very effective in discriminating two different brain states. However, CSP needs a sufficient labeled data set. In order to overcome the drawback of CSP, we suggest a two-stage feature extraction method for the semisupervised learning algorithm. We apply our algorithm to two BCI experimental data sets. The offline data analysis results demonstrate the effectiveness of our algorithm.
Disruption of Type 5 Adenylyl Cyclase Enhances Desensitization of Cyclic Adenosine Monophosphate Signal and Increases Akt Signal With Chronic Catecholamine Stress
Authors: Okumura Satoshi , Vatner Dorothy E. , Kurotani Reiko , Bai Yunzhe , Gao Shumin , Yuan Zengrong , Iwatsubo Kousaku , Ulucan Coskun , Kawabe Jun-ichi , Ghosh Kaushik , Vatner Stephen F. , Ishikawa Yoshihiro
Published: September 2007

Background—

Desensitization of the cyclic adenosine monophosphate signal protects cardiac myocytes against catecholamine stress, thus preventing the development of apoptosis. Molecular mechanisms of desensitization have been well studied at the level of adrenergic receptors but less so at the level of the effector enzyme, adenylyl cyclase (AC).

Methods and Results—

When the effects of long-term (1 to 2 weeks) isoproterenol infusion were compared between type 5 AC-null mice (
AC5KO
) and wild-type controls, we found that the subsequent responses of left ventricular ejection fraction to sudden intravenous isoproterenol challenge were reduced in
AC5KO
compared with wild-type mice (ie, physiological desensitization was more effective in
AC5KO
), consistent with enhanced downregulation of AC catalytic activity in
AC5KO
. One mechanism for the less effective desensitization in wild-type mice was paradoxical upregulation of type 5 AC protein expression. The number of apoptotic myocytes was similar at baseline but was significantly less in
AC5KO
after infusion. This was accompanied by a 4-fold greater increase in Bcl-2 and a 3-fold greater increase in phospho-Akt in
AC5KO
. The latter is most likely mediated by increased membrane localization of phosphoinositide-dependent protein kinase 1, which is known to be inhibited by the cyclic adenosine monophosphate signal.

Conclusions—

The absence of type 5 AC results in more effective desensitization after long-term catecholamine stress and protects against the development of myocyte apoptosis and deterioration of cardiac function, potentially elucidating a novel approach to the therapy of heart failure.
Use of Cardiac Rehabilitation by Medicare Beneficiaries After Myocardial Infarction or Coronary Bypass Surgery
Authors: Suaya Jose A. , Shepard Donald S. , Normand Sharon-Lise T. , Ades Philip A. , Prottas Jeffrey , Stason William B.
Published: September 2007

Background—

Cardiac rehabilitation (CR) is effective in prolonging survival and reducing disability in patients with coronary heart disease. However, national use patterns and predictors of CR use have not been evaluated thoroughly.

Methods and Results—

Using Medicare claims, we analyzed outpatient (phase II) CR use after hospitalizations for acute myocardial infarctions or coronary artery bypass graft surgery in 267 427 fee-for-service beneficiaries aged ≥65 years who survived for at least 30 days after hospital discharge. We used multivariable analyses to identify predictors of CR use and to quantify geographic variations in its use. We obtained unadjusted, adjusted-smoothed, and standardized rates of CR use by state. Overall, CR was used in 13.9% of patients hospitalized for acute myocardial infarction and 31.0% of patients who underwent coronary artery bypass graft surgery. Older individuals, women, nonwhites, and patients with comorbidities (including congestive heart failure, previous stroke, diabetes mellitus, or cancer) were significantly less likely to receive CR. Coronary artery bypass graft surgery during the index hospitalization, higher median household income, higher level of education, and shorter distance to the nearest CR facility were important predictors of higher CR use. Adjusted CR use varied 9-fold among states, ranging from 6.6% in Idaho to 53.5% in Nebraska. The highest CR use rates were clustered in the north central states of the United States.

Conclusions—

CR use is relatively low among Medicare beneficiaries despite convincing evidence of its benefits and recommendations for its use by professional organizations. Use is higher after coronary artery bypass graft surgery than with acute myocardial infarctions not treated with revascularization procedures and varies dramatically by state and region of the United States.
Long-Term Cardiac Effects of Adrenalectomy or Mineralocorticoid Antagonists in Patients With Primary Aldosteronism
Authors: Catena Cristiana , Colussi GianLuca , Lapenna Roberta , Nadalini Elisa , Chiuch Alessandra , Gianfagna Pasquale , Sechi Leonardo A.
Published: September 2007

Exposure to excess aldosterone results in cardiac damage in hypertensive states. We evaluated the long-term cardiac structural and functional evolution in patients with primary aldosteronism after surgical or medical treatment. Fifty-four patients with primary aldosteronism were enrolled in a prospective study and were followed for a mean of 6.4 years after treatment with adrenalectomy (n=24) or spironolactone (n=30). At baseline, echocardiographic measurements of patients with primary aldosteronism were compared with those of 274 patients with essential hypertension. Patients with primary aldosteronism had greater left ventricular mass, more prevalent left ventricular hypertrophy, lower early:late-wave diastolic filling velocities ratio, and longer deceleration time than patients with essential hypertension but no differences in relative wall thickness and systolic function. During follow-up, average blood pressure was 135/82 and 137/82 mm Hg in patients treated with adrenalectomy and spironolactone, respectively. In the initial 1-year period, left ventricular mass decreased significantly only in adrenalectomized patients. Subsequent changes in left ventricular mass were greater in patients treated with spironolactone, with an overall change from baseline to the end of follow-up that was comparable in the 2 groups. Prevalence of hypertrophy decreased in both treatment groups, whereas diastolic parameters had only mild and nonsignificant improvement. Changes in blood pressure and pretreatment plasma aldosterone were independent predictors of left ventricular mass decrease in both treatment groups. Thus, in the long-term, both adrenalectomy and spironolactone are effective in reducing left ventricular mass in patients with primary aldosteronism, with effects that are partially independent of blood pressure changes.
Fourier Analysis of the Envelope of the Ophthalmic Artery Blood Flow Velocity
Authors: Michelson Georg , Harazny Joanna , Schmieder Roland E. , Berendes Rainer , Fiermann Thomas , Wärntges Simone
Published: September 2007

The harmonic content of the envelope waveform of the blood flow velocity in the ophthalmic artery was analyzed in aging and arterial hypertension. The case-control study enrolled 98 healthy men (age: 44.0±15.6 years), 100 healthy women (age: 44.5±19.1 years), which is group 1, and overall 199 hypertensive patients with increased systolic and diastolic blood pressure (in millimeters of mercury) before registration of the blood flow velocity using pulsed Doppler sonography. Group 2 was sufficiently treated (≤140/≤90), group 3 (>140/≤90) and group 5 (>140/>90) were insufficiently treated, and group 4 (>140/≤90) and group 6 (>140/>90) were untreated. Cronbach-α reliability of the calculated spectral coefficient and SI (SI) was 0.88 and 0.93, respectively. In control subjects, the SI was influenced by age (men: 45.1%; women: 50.2%;
P
<0.001 each) and in women additionally by mean arterial pressure (13.1%;
P
<0.001). The SI differed in subjects >43 years of age (men: 0.37±0.11; women: 0.26±0.08;
P
<0.001 each) as compared with subjects ≤43 years of age (men: 0.60±0.18; women: 0.48±0.13). All of these changes were lacking for the resistance index. In both men and women with hypertension, the SI decreases, whereas the mean arterial pressure increases, but the resistance index did not change. The SI of the ophthalmic artery allows an assessment of the ocular circulation in consideration of age and arterial blood pressure in contrast to the resistance index.
Angiotensin II Induces Capillary Formation From Endothelial Cells Via the LOX-1–Dependent Redox-Sensitive Pathway
Authors: Hu Changping , Dandapat Abhijit , Mehta Jawahar L
Published: September 2007

Angiotensin II (Ang II) induces angiogenesis by stimulating reactive oxygen species–dependent vascular endothelial growth factor (VEGF) expression. Ang II via type 1 receptor upregulates the expression of LOX-1, a lectin-like receptor for oxidized low-density lipoprotein. LOX-1 activation, in turn, upregulates Ang II type 1 receptor expression. We postulated that interruption of the feedback loop between Ang II and LOX-1 might attenuate Ang II–induced VEGF expression and capillary formation. In vitro experiments showed that Ang II (1 nmol/L) induced the expression of LOX-1 and VEGF and enhanced capillary formation from human coronary endothelial cells in Matrigel assay. Ang II–mediated expression of LOX-1 and VEGF, capillary formation, intracellular reactive oxygen species generation, and phosphorylation of p38 as well as p44/42 mitogen-activated protein kinases, were suppressed by anti–LOX-1 antibody, nicotinamide-adenine dinucleotide phosphate oxidase inhibitor apocynin and the Ang II type 1 receptor blocker losartan, but not by the Ang II type 2 receptor blocker PD123319. Expression of VEGF and capillary formation induced by Ang II were also inhibited by the p44/42 mitogen-activated protein kinase inhibitor U0126 and the p38 mitogen-activated protein kinase inhibitor SB203580. In ex vivo experiments, Ang II stimulated capillary sprouting from aortic rings from wild-type mice, and this phenomenon was significantly attenuated by pretreatment of aortic rings with anti–LOX-1 antibody, apocynin, and losartan, but not by PD123319. Importantly, Ang II–induced capillary sprouting was minimal from aortic rings from LOX-1 null mice compared with wild-type mice. These findings suggest that small concentrations of Ang II promote capillary formation by inducing the expression of VEGF via Ang II type 1 receptor/LOX-1–mediated stimulation of the reactive oxygen species-mitogen-activated protein kinase pathway.
Congenic Interval Mapping of RNO10 Reveals a Complex Cluster of Closely-Linked Genetic Determinants of Blood Pressure
Authors: Saad Yasser , Yerga-Woolwine Shane , Saikumar Jagannath , Farms Phyllis , Manickavasagam Ezhilarasi , Toland Edward J. , Joe Bina
Published: September 2007

Genetic dissection of the rat genome for identifying alleles that cause abnormalities in blood pressure (BP) resulted in the mapping of a significant number of BP quantitative trait loci (QTLs). In this study we mapped at least one such BP QTL on rat chromosome 10 (RNO10) as being within the introgressed segment of a S.LEW congenic strain S.LEWx12x2x3x8 spanning 1.34 Mb from 70 725 437 bp to 72 063 232 bp. BP of 3 congenic strains that span shorter segments of this region was additionally examined. Results obtained indicate that LEW alleles that comprise a 375-kb introgressed segment of the congenic strain S.LEWx12x2x3x5 (70 725 437 bp to 71 100 513 bp) increase BP. The magnitude of change in BP exhibited by the 2 strains, S.LEWx12x2x3x8 and S.LEWx12x2x3x5, is the net phenotypic effect of the underlying genetic determinants of BP. In this respect, the current data are superior to previous QTL localization of BP QTL1, which was hypothesized based on differential congenic segments. Genetic dissection using these 2 congenic strains as tools is expected to facilitate further dissection of the regions. Meanwhile, differential congenic segments were used to predict and thereby prioritize regions for candidate gene analysis. Using this approach, 2 distinct regions of 401 kb and 409 kb within S.LEWx12x2x3x8 and a 104 kb region within S.LEWx12x2x3x5 were prioritized for further consideration. Because all of these genetic elements are located within a 1.06-Mb region of RNO10, our study has revealed a remarkable insight into a genomic module comprising very closely-linked, opposing genetic determinants of BP.
Male Gender Role Conflict and Multiculturalism
Authors: Wester Stephen R.
Published: September 2007

The new multicultural guidelines reemphasized the importance of developing knowledge of, and skills in working with, individuals outside of the majority group. In this article, the author will detail recent advances in understanding how identified consequences of male gender role socialization, specifically male gender role conflict (GRC), intersect with other aspects of race, cultures, and sexual orientations. The literature surrounding male gender role conflict will be briefly summarized. Next, the multicultural competencies framework of beliefs and attitudes, knowledge, and skills, will be used to outline how GRC might apply to some men of color and offer suggestions for counseling practice. After synthesizing what this might offer counseling psychologists, the general implications for research and theory will be explored.
Suicide Risk Assessment With Asian American College Students
Authors: Choi Jayoung L. , Rogers James R. , Werth James L.
Published: September 2007

Scholars have based their understanding of college-student suicide in the United States largely on the study of European Americans, and therefore, its relevance to making culturally informed decisions with suicidal Asian American college students is unclear. This article explores aspects of suicide assessment potentially unique to Asian American college students and discusses possible ways to handle the process of breaking confidentiality that are more sensitive to Asian American needs. First, the authors briefly review issues of confidentiality, informed consent, and standards of care. Second, they examine several aspects of Asian American college students' experiences in the United States and of Asian cultural values. Specifically, the authors review acculturation and the experience of immigration, intergenerational relationships, collectivistic cultural values, the myth of the “model minority,” and perfectionism. Third, they offer culturally informed considerations for assessing suicidal risk and ways to manage breaking confidentiality. Finally, they suggest the Collaborative Assess-ment and Management of Suicidality model and the Suicide Intervention Response Inventory−2 as potentially useful tools for culturally sensitive work with Asian American college students.
Resistance leadership: The overlooked potential in critical organization and leadership studies
Authors: Zoller Heather M. , Fairhurst Gail T.
Published: September 2007

This article examines the role of leadership in mobilizing collective resistance in the workplace. Given the scarcity of dialogue between critical scholars and leadership studies, relatively little consideration is given to the role of leadership in resisting and potentially transforming structures of domination. The article describes some of the reasons why these areas of research have produced so little mutual work. We then make the argument that theories of leadership can be useful to the study of resistance by providing a grounded approach to theorizing agency, highlighting the role of mobilization and influence in change, and emphasizing participant attributions. In doing so, leadership studies gain important insights about the influence of deep structure power issues on perceptions of leaders, as well as material and symbolic limits on mobilization. The article adopts a dialectical perspective as a way of understanding issues of resistance leadership, and then discusses how existing literatures, read with this dialectical approach, can be brought to bear on significant questions concerning the practices of resistance leadership.
Playing tick-box games: Interrelating defences in professional appraisal
Authors: McGivern Gerry , Ferlie Ewan
Published: September 2007

We here examine the introduction of appraisal for senior medical professionals. Our recent qualitative field research found four main experiences of appraisal (developmental, disappointed reflection, defensive assessment and cynical dismissal of appraisal as a waste of time), which we developed into a typology. We argue many professionals `play tick-box games' to give the impression of auditable practice while continuing to practise in a traditional way. We develop existing theory on the `audit society', social defences and `mock bureaucracy' to explain interrelating defences which occur in appraisal as a reaction to the risks and conflict experienced in professional regulation.
Oedipus Rex at Enron: Leadership, Oedipal struggles, and organizational collapse
Authors: Stein Mark
Published: September 2007

This article is intended to contribute to our understanding of the December 2001 collapse of Enron. The existing literature on Enron's demise falls largely into two broad areas, involving either `micro' psychological explanations or `macro' accounts that emphasize the workplace and its environment; this article is an exploratory study that focuses on a new interpretation which links the two areas more closely together. It is proposed that Enron's culture was influenced by both `micro' and `macro' factors: an experience of unsuccessful paternal authority figures within the family history of Enron's leaders, coupled with an experience of problematic government and regulatory regimes associated with the gas industry. Drawing on concepts from psychoanalysis and its application to organizational dynamics, it is argued that these `micro' and `macro' factors helped to generate an Oedipal mindset in Enron's leaders according to which external authority was seen to be weak and not worthy of respect, and that this contributed to Enron's demise. Implications for theory are examined.
Towards a Unified Approach to Motion Planning for Dynamic Underactuated Mechanical Systems with Non-holonomic Constraints
Authors: Shammas Elie A. , Choset Howie , Rizzi Alfred A.
Published: September 2007

In this paper, we generalize our prior results in motion analysis to design gaits for a more general family of underactuated mechanical systems. In particular, we analyze and generate gaits for mixed mechanical systems which are systems whose motion is simultaneously governed by both a set of non-holonomic velocity constraints and a notion of a generalized momentum being instantaneously conserved along allowable directions of motion. Through proper recourse to geometric mechanics, we are able to show that the resulting motion from a gait has two portions: a geometric and a dynamic contribution. The main challenge in motion planning for a mixed system is understanding how to separate the geometric and dynamic contributions of motion due to a general gait, thus simplifying gait analysis. In this paper, we take the first step towards addressing this challenge in a generalized framework. Finally, we verify the generality of our approach by applying our techniques to novel mechanical systems which we introduce in this paper as well as by verifying that seemingly different prior motion planning results could actually be explained using the gait analysis presented in this paper.
Psychiatric Use and Utility of Divalproex Sodium in Connecticut Prisons
Authors: Kamath Jayesh , Temporini Humberto D. , Quarti Susan , Wanli Zhang  , Pagano Karen L. , DeMartinis Nicholas , Trestman Robert L.
Published: September 2007

Divalproex sodium (DVX) is used in correctional settings to treat impulsive aggression and mood lability in patients without comorbid bipolar disorder. This review of DVX use in the Connecticut Department of Correction examined the psychiatric diagnostic impression of patients prescribed DVX, the doses used, and the symptomatic and functional change over time. Clinical charts of 168 offenders treated with DVX for one or more months were randomly selected for clinical outcome review and were divided into subgroups based on clinical impression for DVX prescription. In participants without bipolar disorder (44.6%), DVX was used to target impulsivity (14.3%) and mood lability (17.3%). Clinical improvement was noted in bipolar and nonbipolar groups ( p < .001). The impulsive/aggressive subgroup was the only nonbipolar subgroup in which DVX yielded clinical benefit. This symptom-driven use of DVX is associated with clinical improvement when impulsive aggression is the target symptom.
The Prevalence of Sexual Violence in Prison
Authors: Jones Tonisha R. , Pratt Travis C.
Published: September 2007

The issue of prison violence and misconduct has been the subject of considerable academic attention, yet particularized areas of violent victimization within prisons have gone relatively unnoticed. One such area involves sexual violence in prisons. Scholars have argued that sexual violence contributes to a host of institutional and individual-level problems, yet the primary limitation of this body of literature is that it has been largely confined to methodologically questionable studies of prison rape prevalence. The purpose of this study, therefore, is to critically take stock of what is and what is not currently known about the prevalence of prison sexual violence. In doing so, it highlights the direction that future research should take so that evidence-based policies concerning prison sexual violence may be developed.
Simplified Pharmacoeconomics of Critical Care and Severe Sepsis
Authors: Ernst Frank R. , Levy Howard , Qualy Rebecca L.
Published: September 2007

Understanding pharmacoeconomic evaluation can empower clinicians to be stronger decision makers. However, cost-effectiveness analyses (CEAs) in critical care are sometimes not easy to understand and often not placed in context with other interventions. The purpose of this article is to clarify and simplify the CEA process using examples from critical care and severe sepsis. First discussed is cost-effectiveness as a framework for clinical decision making and how it compares to other types of economic evaluations. Then important considerations when conducting or reviewing CEAs are explored, such as perspective, discounting, sensitivity analysis, and grading of CEAs, as well as shortcomings and resistance to using CEAs. Next, applications of CEA in critical care and severe sepsis are reviewed. Included is the Food and Drug Administration-approved drug for severe sepsis, drotrecogin alfa (activated), as an example of a recently new critical care intervention that resulted in significant interest in understanding cost-effectiveness. Finally, CEAs of other medical and nonmedical interventions are placed in context with CEAs from critical care. Understanding pharmacoeconomic evaluation can empower clinicians to be stronger decision makers. CEAs provide decision makers a quantitative measure of the value of therapeutic options that can guide clinicians toward balancing the cost burdens of therapy with their profound effects and choosing between options that compete for funding.
Cardiologists Use Pulmonary Artery Catheter Information to Make Homogenous Treatment Decisions
Authors: Jain Manu , Upadhyay Daya , Balagani Rajesh , Jovanovic Borko , Fintel Dan
Published: September 2007

Medical intensivists make heterogenous decisions using pulmonary artery catheter (PAC) data in medical intensive care unit patients. The object was to determine if cardiologists given PAC data from critically ill cardiology patients make uniform management choices. A survey questionnaire containing 3 coronary care unit (CCU) clinical vignettes was designed and mailed to board-certified cardiologists who are members of the American College of Cardiology. Twenty board-certified medical intensivists were also asked to complete the vignettes. Each vignette contained PAC data and one-half of the surveys contained echocardiographic (ECHO) information. Every respondent was asked to select 1 of 6 interventions for each vignette. In 2 of 3 vignettes 1 intervention was selected by more than 70% of cardiologists. In the third vignette, 1 intervention was selected by more than 50% of cardiologists. For each vignette, 1 intervention was selected by at least 75% of medical intensivists. There was no significant difference in the distribution of management choices between the ECHO and the non-ECHO subgroups. There is relative homogeneity in selecting an intervention based on PAC data among cardiologists and medical intensivists in CCU patients and is probably due to patient-related factors. The presence of ECHO information did not change the intervention selected. Cardiology patients may represent an ideal group in which to evaluate PAC efficacy.
The Use of Clinical Simulation Systems to Train Critical Care Physicians
Authors: Lighthall Geoffrey K. , Barr Juliana
Published: September 2007

Intensive care units are complex and dynamic clinical environments in which the delivery of appropriate and timely care to critically ill patients depends on the integrated and efficient actions of providers with specialized training. The use of realistic clinical simulator systems can help to facilitate and standardize the training of critical-care physicians, nurses, respiratory therapists, and pharmacists without having the training process jeopardize the well-being of patients. In this article, we review the current state of the art of patient simulator systems and their applications to critical-care medicine, and we offer some examples and recommendations on how to integrate simulator systems into critical-care training.