bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypoxia tolerance in elasmobranchs. II. Cardiovascular function and tissue metabolic responses during progressive and relative hypoxia exposures
Authors: Speers-Roesch Ben , Brauner Colin J. , Farrell Anthony P. , Hickey Anthony J. R. , Renshaw Gillian M. C. , Wang Yuxiang S. , Richards Jeffrey G. 
Published: December 2011

SUMMARYCardiovascular function and metabolic responses of the heart and other tissues during hypoxia exposure were compared between the hypoxia-tolerant epaulette shark (Hemiscyllium ocellatum) and the hypoxia-sensitive shovelnose ray (Aptychotrema rostrata). In both species, progressive hypoxia exposure caused increases in stroke volume and decreases in heart rate, cardiac output, cardiac power output (CPO, an assessment of cardiac energy demand) and dorsal aortic blood pressure, all of which occurred at or below each species' critical PO2 for whole-animal O2 consumption rate, (Pcrit). In epaulette sharks, which have a lower Pcrit than shovelnose rays, routine levels of cardiovascular function were maintained to lower water PO2 levels and the changes from routine levels during hypoxia exposure were smaller compared with those for the shovelnose ray. The maintenance rather than depression of cardiovascular function during hypoxia exposure may contribute to the superior hypoxia tolerance of the epaulette shark, presumably by improving O2 delivery and waste removal. Compared with shovelnose rays, epaulette sharks were also better able to maintain a stable cardiac high-energy phosphate pool and to minimize metabolic acidosis and lactate accumulation in the heart (despite higher CPO) and other tissues during a 4 h exposure to 40% of their respective Pcrit (referred to as a relative hypoxia exposure), which results in similar hypoxaemia in the two species (∼16% Hb–O2 saturation). These different metabolic responses to relative hypoxia exposure suggest that variation in hypoxia tolerance among species is not solely dictated by differences in O2 uptake and transport but also by tissue-specific metabolic responses. In particular, lower tissue [lactate] accumulation in epaulette sharks than in shovelnose rays during relative hypoxia exposure suggests that enhanced extra-cardiac metabolic depression occurs in the former species. This could facilitate strategic utilization of available O2 for vital organs such as the heart, potentially explaining the greater hypoxic cardiovascular function of epaulette sharks.
Oxygen utilization and the branchial pressure gradient during ram ventilation of the shortfin mako,Isurus oxyrinchus: is lamnid shark–tuna convergence constrained by elasmobranch gill morphology?
Authors: Wegner Nicholas C. , Lai N. Chin , Bull Kristina B. , Graham Jeffrey B. 
Published: December 2011

SUMMARYRam ventilation and gill function in a lamnid shark, the shortfin mako, Isurus oxyrinchus, were studied to assess how gill structure may affect the lamnid–tuna convergence for high-performance swimming. Despite differences in mako and tuna gill morphology, mouth gape and basal swimming speeds, measurements of mako O2 utilization at the gills (53.4±4.2%) and the pressure gradient driving branchial flow (96.8±26.1 Pa at a mean swimming speed of 38.8±5.8 cm s–1) are similar to values reported for tunas. Also comparable to tunas are estimates of the velocity (0.22±0.03 cm s–1) and residence time (0.79±0.14 s) of water though the interlamellar channels of the mako gill. However, mako and tuna gills differ in the sites of primary branchial resistance. In the mako, approximately 80% of the total branchial resistance resides in the septal channels, structures inherent to the elasmobranch gill that are not present in tunas. The added resistance at this location is compensated by a correspondingly lower resistance at the gill lamellae accomplished through wider interlamellar channels. Although greater interlamellar spacing minimizes branchial resistance, it also limits lamellar number and results in a lower total gill surface area for the mako relative to tunas. The morphology of the elasmobranch gill thus appears to constrain gill area and, consequently, limit mako aerobic performance to less than that of tunas.
Earliest ciliary swimming effects vertical transport of planktonic embryos in turbulence and shear flow
Authors: McDonald Kathryn A. 
Published: December 2011

SUMMARY
Eggs released by broadcast-spawning marine invertebrates are often negatively buoyant. Blastulae and gastrulae of these species are commonly motile, with passive stability that leads to upward swimming in still water. The earliest occurrence of swimming in developing embryos of diverse invertebrates may therefore permit vertical migration in nature. I used turbulent and laminar shear flows to investigate: (1) the speed and direction of transport of non-motile and newly swimming stages of the echinoids Dendraster excentricus and Strongylocentrotus purpuratus in turbulence, and (2) the limit of stable vertical orientation in swimming blastulae of D. excentricus. Swimming contributed significantly to the rate of upward transport of D. excentricus in turbulence experiments where the kinetic energy dissipation rate (ε) was ∼10–2cm2s–3. However, swimming significantly reduced the rate of upward transport of S. purpuratus blastulae in turbulence, suggesting that passively stable swimmers of this species were turned from the vertical, crossed flow-lines, and migrated into downwelling. Observations of swimming in laminar shear indicate that D. excentricus swimming blastulae maintain a vertical orientation until shear approaches 0.26s–1, equivalent to sub-microscale shear in turbulence where ε is ∼10–3cm2s–3. Swimming speeds of D. excentricus showed an unexpected dependence on shear, indicating that greater shear (within limits) can enhance speed of ciliary swimming. In D. excentricus, swimming by newly hatched blastulae should support upward migration in turbulence characteristic of coastal surface waters, whereas species differences in passive stability and swimming responses to shear may lead to differences in vertical transport and subsequent dispersal.
Surface roughness effects on attachment ability of the spider Philodromus dispar (Araneae, Philodromidae)
Authors: Wolff Jonas O. , Gorb Stanislav N. 
Published: December 2011

SUMMARY
The morphology of the tarsal attachment system of the running spider Philodromus dispar Walckenaer 1826 (Araneae, Philodomidae) was studied using scanning electron microscopy and its performance was experimentally tested in traction force measurements. Each pretarsus bears a hierarchically built hairy adhesive pad that consists of a dense array of flattened setae covered with numerous microtrichia on the substrate-facing side. Microtrichia carry spatulate end tips that allow close contact with the substrate. Forces were estimated on tethered living specimens on rough epoxy resin surfaces (asperity size 0.3, 1, 3, 9 and 12 μm) and on a smooth surface as a control. A strong reduction in adhesion was observed for substrates with an asperity size of 0.3 and 1 μm. Comparison of the present data with previous results of different organisms demonstrates that the difference in force reduction on rough substrata depends on the dimensions of terminal contact elements (spatulae).
A robotic fish caudal fin: effects of stiffness and motor program on locomotor performance
Authors: Esposito Christopher J. , Tangorra James L. , Flammang Brooke E. , Lauder George V. 
Published: December 2011

SUMMARY
We designed a robotic fish caudal fin with six individually moveable fin rays based on the tail of the bluegill sunfish, Lepomis macrochirus. Previous fish robotic tail designs have loosely resembled the caudal fin of fishes, but have not incorporated key biomechanical components such as fin rays that can be controlled to generate complex tail conformations and motion programs similar to those seen in the locomotor repertoire of live fishes. We used this robotic caudal fin to test for the effects of fin ray stiffness, frequency and motion program on the generation of thrust and lift forces. Five different sets of fin rays were constructed to be from 150 to 2000 times the stiffness of biological fin rays, appropriately scaled for the robotic caudal fin, which had linear dimensions approximately four times larger than those of adult bluegill sunfish. Five caudal fin motion programs were identified as kinematic features of swimming behaviors in live bluegill sunfish, and were used to program the kinematic repertoire: flat movement of the entire fin, cupping of the fin, W-shaped fin motion, fin undulation and rolling movements. The robotic fin was flapped at frequencies ranging from 0.5 to 2.4 Hz. All fin motions produced force in the thrust direction, and the cupping motion produced the most thrust in almost all cases. Only the undulatory motion produced lift force of similar magnitude to the thrust force. More compliant fin rays produced lower peak magnitude forces than the stiffer fin rays at the same frequency. Thrust and lift forces increased with increasing flapping frequency; thrust was maximized by the 500× stiffness fin rays and lift was maximized by the 1000× stiffness fin rays.
The energetics of running stability: costs of transport in grass-cutting ants depend on fragment shape
Authors: Moll Karin , Federle Walter , Roces Flavio 
Published: December 2011

SUMMARYGrass-cutting ants (Atta vollenweideri) carry fragments that can be many times heavier and longer than the ants themselves and it is important for them to avoid falling over during load transport. To investigate whether the energetic costs of transport are affected by the need to maintain stability, the rate of CO2 production was measured in both unladen workers and workers carrying standardized paper fragments of different size and shape. We tested: (1) the effect of mass by comparing workers carrying either light or heavy fragments of the same size, and (2) the effect of shape by comparing short and long fragments of the same mass. Consistent with previous studies, metabolic rate increased but running speed remained constant when ants carried heavier fragments. The net cost of transport (normalized to the total mass of ant and fragment) was the same for heavy and light fragments, and did not differ from the costs of carrying a unit body mass. Ants carrying long fragments showed similar metabolic rates but ran significantly slower than ants carrying short fragments. As a consequence, net cost of transport was significantly higher for long fragments than for short ones, and higher than the costs of carrying a unit body mass. The observed reduction in running speed is likely a result of the ants' need to maintain stability. When the absolute costs of transport were compared, smaller ants required more energy to carry heavier and longer fragments than larger workers, but the opposite was found for lighter and shorter fragments. The absolute costs of transport per unit fragment mass suggest that it is energetically advantageous for a colony to allocate smaller workers for the transport of small fragments and larger workers for large fragments. The present results underline the importance of biomechanical factors for the understanding of leaf-cutting ant foraging strategies.
Point of no return in diving emperor penguins: is the timing of the decision to return limited by the number of strokes?
Authors: Shiomi Kozue , Sato Katsufumi , Ponganis Paul J. 
Published: December 2011

SUMMARY
At some point in a dive, breath-hold divers must decide to return to the surface to breathe. The issue of when to end a dive has been discussed intensively in terms of foraging ecology and behavioral physiology, using dive duration as a temporal parameter. Inevitably, however, a time lag exists between the decision of animals to start returning to the surface and the end of the dive, especially in deep dives. In the present study, we examined the decision time in emperor penguins under two different conditions: during foraging trips at sea and during dives at an artificial isolated dive hole. It was found that there was an upper limit for the decision-to-return time irrespective of dive depth in birds diving at sea. However, in a large proportion of dives at the isolated dive hole, the decision-to-return time exceeded the upper limit at sea. This difference between the decision times in dives at sea versus the isolated dive hole was accounted for by a difference in stroke rate. The stroke rates were much lower in dives at the isolated hole and were inversely correlated with the upper limit of decision times in individual birds. Unlike the decision time to start returning, the cumulative number of strokes at the decision time fell within a similar range in the two experiments. This finding suggests that the number of strokes, but not elapsed time, constrained the decision of emperor penguins to return to the surface. While the decision to return and to end a dive may be determined by a variety of ecological, behavioral and physiological factors, the upper limit to that decision time may be related to cumulative muscle workload.
Ketamine in Adult Emergency Medicine: Controversies and Recent Advances
Authors: Sih Kendra , Campbell Samuel G , Talion John M , Magee Kirk , Zed Peter J 
Published: December 2011

Objective: To review the evidence for the use of ketamine in adult emergency medicine for procedural sedation and analgesia (PSA) and rapid sequence intubation (RSI), as well as to focus on the issues of recovery agitation, combination with propofol for PSA, and the use of ketamine as an induction agent in patients with acute head injury in need of definitive airway management. Data Sources: PubMed (1949-July 2011), EMBASE (1980-July 2011), Google Scholar (to July 2011), International Pharmaceutical Abstracts (1964-July 2011), and Cochrane databases were searched independently. A manual search of references was also performed, Study Selection: English-language, full reports of experimental and observational studies evaluating ketamine in adults undergoing PSA and RSI in the emergency department (ED) were Included if they reported efficacy or safety outcomes. Data Extraction: Two reviewers independently assessed each article for inclusion, data extraction, and study limitations. Data Synthesis: Six studies that used ketamine for PSA were included. The majority reported adequate sedation with high patient satisfaction and lack of pain and procedural recall. There is no evidence to support the superiority of a combination of ketamine and propofol compared to propofol alone for PSA in adults. Recovery agitation is common but can be minimized with premedication with midazolam (number needed to treat 6). Two studies were identified that evaluated the role of ketamine for induction during RSI in the ED, Although ketamine is not a first-line agent for RSI, it is an alternative and may be used as an induction agent in patients requiring endotracheal intubation. Conclusions: Ketamine is an effective agent in adults undergoing PSA and RSI in the ED. The best available evidence provides sufficient confidence to consider use of this agent in the ED.
Disparities in Blood Pressure Control Within a Community-Based Provider Network: An Exploratory Analysis
Authors: Romanelli Robert J , Schiro Timothy A , Jukes Trevor , Wong Ken S , Ishisaka Denis Y 
Published: December 2011

Background: Despite treatment for hypertension, blood pressure (BP) remains uncontrolled in many individuals. Identification of patterns in BP control may inform strategies to improve treatment and optimize health outcomes. Objective: To examine patterns in BP control among individuals receiving antihypertensive treatment in a diverse, community-based provider network. Methods: In this retrospective exploratory analysis, a total of 51.772 hypertensive subjects were identified in the electronic medical record between January 1, 2007, and June 30, 2010, who were aged 18 years or older, with 2 or more claims for antihypertensive medication, documented race/ethnicity, and 1 or more documented BP readings. Results: On the basis of Joint National Committee VII guidelines, 76.4% of nondiabetic patients had their BP controlled with treatment (<140/90 mm Hg) and 52.3% of those with diabetes had their BP controlled with treatment (<130/80 mm Hg). The overall rate of BP control was 71.4%. Factors associated with controlled BP included younger age, lower disease burden, better medication adherence, fewer concurrent prescriptions, lower prescription copayments, and living in a region with a higher median household income. Furthermore, when adjusting for age, sex, and disease burden, black (OR 0.68; 95% Cl 0.62 to 0.75; p < 0.001), Hispanic (OR 0.80; 95% Cl 0.74 to 0.86; p < 0.001), and other race/ethnic group (OR 0.81; 95% Cl 0.70 to 0.94; p = 0.005) individuals were less likely than white individuals to have their treated BP controlled. Among nondiabetic hypertensive subjects with controlled BP, the most frequently prescribed therapy was a β-blocker or an angiotensin-converting enzyme (ACE) inhibitor across race/ethnicities; however, those who were black were most frequently prescribed a diuretic or calcium channel blocker. Among diabetic patients with controlled BP, the most frequently prescribed therapy was an ACE inhibitor, regardless of race/ethnicity. Conclusions: Potential disparities, particularly among diabetic individuals and those of minority race/ethnicity, were found with regard to BP control and the agents used to treat hypertension. Future studies should address these disparities by designing interventions to improve the treatment of hypertension in high-risk populations.
When to Wait for More Evidence? Real Options Analysis in Proton Therapy
Authors: Grutters Janneke P.C. , Abrams Keith R. , de Ruysscher Dirk , Pijls-Johannesma Madelon , Peters Hans J.M. , Beutner Eric , Lambin Philippe , Joore Manuela A. 
Published: December 2011

AbstractPurpose.Trends suggest that cancer spending growth will accelerate. One method for controlling costs is to examine whether the benefits of new technologies are worth the extra costs. However, especially new and emerging technologies are often more costly, while limited clinical evidence of superiority is available. In that situation it is often unclear whether to adopt the new technology now, with the risk of investing in a suboptimal therapy, or to wait for more evidence, with the risk of withholding patients their optimal treatment. This trade-off is especially difficult when it is costly to reverse the decision to adopt a technology, as is the case for proton therapy. Real options analysis, a technique originating from financial economics, assists in making this trade-off.Methods.We examined whether to adopt proton therapy, as compared to stereotactic body radiotherapy, in the treatment of inoperable stage I non-small cell lung cancer. Three options are available: adopt without further research; adopt and undertake a trial; or delay adoption and undertake a trial. The decision depends on the expected net gain of each option, calculated by subtracting its total costs from its expected benefits.Results.In The Netherlands, adopt and trial was found to be the preferred option, with an optimal sample size of 200 patients. Increase of treatment costs abroad and costs of reversal altered the preferred option.Conclusion.We have shown that real options analysis provides a transparent method of weighing the costs and benefits of adopting and/or further researching new and expensive technologies.
From Student to Accounting Professional: A Longitudinal Study of the Filtering Process
Authors: Swain Monte R. , Olsen Kari Joseph 
Published: December 2011

ABSTRACTOver a 15-year period, we observe the pattern of personality types of students that come into introductory accounting classes, into the accounting major, into the accounting profession, and that remain in accounting as a long-term career. While most research has concentrated on either education or professional careers, our study represents perhaps the first significant longitudinal study employing a within-subject design to examine both the accounting education decision, and the decision to pursue and remain with an accounting career. By employing mediational analysis techniques, our study examines the filtering process that leads to the personality makeup of practicing accountants. Our analysis extends beyond descriptive correlations of MBTI personality types majoring in accounting to provide evidence of how MBTI personality type preferences influence career decisions through mediated measures of attitude, intent, and performance. In particular, we demonstrate clearly both the nature and the preponderance of personality types in both the accounting major and accounting profession who prefer gathering information based on observations of concrete data versus gathering insight based on an intuitive exploration of meanings and relationships—classified in the MBTI personality literature as Sensors versus Intuitors, respectively.Data Availability: Data available upon request.
Using Graphical Representations of Business Processes in Evaluating Internal Control
Authors: Borthick A. Faye , Schneider Gary P. , Vance Anthony 
Published: December 2011

ABSTRACT
In this case, students (1) extend business process diagrams (BPD) to represent current and contemplated business processes for accounts payable processing for a convenience store company's merchandise purchases and (2) use the graphical representations of the business processes to identify control weaknesses and their potential effects on the financial statements and operational effectiveness. The case is appropriate for students developing skills in documenting business processes and evaluating internal control in business processes in introductory courses in accounting information systems (AIS), auditing, and information technology (IT) auditing. Before beginning the case, students should be familiar with the procure-to-pay process, preparing BPDs, and identifying internal control weaknesses in business processes. Working the case requires students to think critically about the business processes and the implications of differences in current and contemplated processes.
The Activities of the Pathways Commission and the Historical Context for Changes in Accounting Education
Authors: Black William H. 
Published: December 2011

ABSTRACT
The Pathways Commission examined accounting education in the United States in response to a recommendation from the U.S. Treasury Advisory Committee on the Auditing Profession. This paper summarizes the Pathways activities and process during 2010 and 2011, and sets forth a historical context to help understand the recommendations for change in accounting education over the last several decades.
Asymmetric double quantum wells with smoothed interfaces
Authors: Gavryushin Vladimir 
Published: December 2011

Abstract
We have derived and analyzed the wavefunctions and energy states for an asymmetric double quantum well (ADQW), broadened due to interdiffusion or other static interface disorder effects, within a known discreet variable representative approach for solving the one-dimensional Schrodinger equation. The main advantage of this approach is that it yields the energy eigenvalues, and the eigenvectors, in semiconductor nanostructures of different shapes as well as the strengths of the optical transitions between them. The behaviour of ADQW states for the different mutual widths of coupled wells, for the different degree of broadening, and under increasing external electric field is investigated. We have found that interface broadening effects change and shift energy levels, not monotonously, but the resonant conditions near an energy of sub-band coupling regions do not strongly distort. Also, it is shown that an external electric field may help to achieve resonant conditions for inter-sub-band inverse population by intrawell emission of LO-phonons in diffuse ADQW.