bluuebunny/crossref_metadata_2025 huggingface dataset:
Occurrence and possible significance of rare Ti oxides (Magnéli phases) in carbonaceous chondrite matrices
Authors: Brearley Adrian J.
Published: December 2015

Abstract— Rare, ultrafine‐grained Ti oxides (Ti3O5 and the Magnéli phases, Ti5O9 and Ti8O15) have been identified by transmission electron microscopy in the CM2 carbonaceous chondrite, Bells and a carbonaceous chondrite matrix clast from the Nilpena polymict ureilite. In both meteorites the Ti oxides occur in the matrix as isolated grains and clusters of two or more grains. They are euhedral in shape and have grain sizes of 0.05–0.3 μm. Magnéli phases have been recently shown to be a common component in some interplanetary dust particles, but this is the first reported occurrence in a meteorite. The morphological properties and grain size of the Ti oxides are consistent with formation by vapor phase condensation either within the solar nebula or possibly in a presolar environment.
Guidelines for the naming of new meteorite finds from the Nullarbor Region, South Australia
Authors: Bevan A. W. R. , Pring A.
Published: December 2015

Abstract— To date, 24 possibly distinct meteorites have been reported from the Nullarbor Region in South Australia and many more recoveries remain to be described. Following Bevan and Binns (1989), the system of nomenclature for meteorites from the Western Australian Nullarbor has been extended into the South Australian Nullarbor. For the purposes of nomenclature, the South Australian Nullarbor has been divided into 27 named “areas.” Henceforth, distinct meteorites will take the name of the area in which they were found and a number (e.g., 001). The names of previously documented meteorites from the region remain unchanged.
Peak atmospheric entry temperatures of micrometeorites
Authors: Love Stanley G. , Brownlee Donald E.
Published: December 2015

Abstract— We present numerical calculations of the peak temperatures experienced by micrometeorites during atmospheric entry. Results are given for particle diameters between 2 and 50 μm and for entry velocities between 10 and 25 km/s. A material density of 2 g/cm3 and an entry angle of 45° are used for the calculation, but the results presented here can be easily reinterpreted for other densities and for vertical entry.
Further classification of ordinary chondrites from the Monnig Collection
Authors: Ehlmann Arthur J. , Keil Klaus
Published: December 2015

Abstract— Four ordinary chondrites from the Oscar Monnig Meteorite Collection were classified into compositional groups, petrologic types, and shock stages: Wray (b), Colorado, L5S2; Round Top (a), Texas, L5S3; Round Top (b), Texas, H4S3; Hassayampa, Arizona, H4S3.
Origin of tektites
Authors: O'Keefe John A.
Published: December 2015

Abstract— The origin of tektites has been obscure because of the following dilemma. The application of physical principles to the data available on tektites points strongly to origin from one or more lunar volcanoes; but few glasses of tektite composition have hitherto been reported from the lunar samples. Instead, the lunar silicic glasses consist chiefly of a material very rich in K2O and poor in MgO. The ratio of K2O/MgO is higher in these glasses than in any tektites reported. The solution of the dilemma seems to come from the study of some recently discovered terrestrial deposits of tektite glass with high values of K2O/MgO at the Cretaceous‐Tertiary boundary. These glasses are found to be very vulnerable to crystallization into sandine or to alteration to smectite. These end products are known and are more abundant than any terrestrial deposits of tektite glass. It seems possible that, in fact, the moon produces tektite glass, mostly of the high K2O‐low MgO type; but on Earth these deposits are destroyed. The much less abundant deposits with lower K and higher Mg are observed because they survive. Other objections to the lunar origin hypothesis appear to be answerable.
Magnetic spherules from Pleistocene sediments in Alberta, Canada
Authors: Bi Dong
Published: December 2015

Abstract— Magnetic spherules have recently been found in Pleistocene sediments in Alberta, Canada. The spherules are composed of magnetite (FeFe2O4) and wüstite (Fe1‐xO); some have metallic cores composed of pure α‐Fe metal. Other metal cores contain from 0.1% to 0.88% Ni by weight. Comparison of morphology, internal structure and chemical and mineralogical compositions with those of spherules of known origin suggests that the Alberta spherules are of extraterrestrial origin.
Shock metamorphism in quartz at Sevetin and Susice (Bohemia)? A TEM investigation
Authors: Cordier P. , Vrána S. , Doukhan J. C.
Published: December 2015

Abstract— The possible impact origin of the Sevetin and Susice structures (Bohemia, Czech Republic) has been tested by searching for shock metamorphism in quartz. Transmission Electron Microscopy (TEM) investigation revealed microstructures originating only from tectonic deformation. No lattice defects characteristic of shock deformation have been detected, even considering possible annealing of microstructures. An impact origin for Sevetin and Susice is not supported by TEM study.
Attachment Theory as a Model of Doctor–Patient Interaction
Authors: Cassedy Hannah F. , Enander Richard A. , Robinson Richard C. , Evans H. Monroe , Frank Blake , Tucker Christy , Miltenberger Paula D. , Pitts Sandra , Stringer C. Allen
Published: December 2015

Individuals' attachment styles have been traced throughout the life span, informing our understanding of long‐standing interpersonal patterns and self‐care habits. Recent scholarship has identified direct and indirect mechanisms through which attachment theory may impact individuals' health outcomes, with specific emphasis on endocrine and behavioral responses to stress. This article reviews extant literature on medical patients' attachment styles and also proposes a new line of research: an investigation of the interaction between patients' and providers' attachment styles. As medical establishments place more emphasis on effective patient–provider communication, attachment theory serves as an apt framework for clarifying, measuring, and training medical personnel in the advancement of patient‐centered care.
Why Speciesism is Wrong: A Response to Kagan
Authors: Singer Peter
Published: December 2015

In Animal Liberation I argued that we commonly ignore or discount the interests of sentient members of other species merely because they are not human, and that this bias in favour of members of our own species is, in important respects, parallel to the biases that lie behind racism and sexism. Shelly Kagan, in ‘What's Wrong With Speciesism’ misconstrues this argument, as well as the principle of equal consideration of interests, which I offer as an alternative to speciesism. Kagan also offers, as an alternative explanation of, and possible justification for, our discounting the interests of nonhuman animals, the suggestion that your interests count more if you are a member of a species whose typical adult members are persons. Although this view is not a form of speciesism, Kagan seems not to be aware of the fact that it is a view commonly defended by advocates of natural law ethics, on which there is already an extensive critical literature.
Psychophysical Validation of A Digital Method to Assess Ill‐Defined Visual Boundaries: An Example with Fabric Openness Factor
Authors: Tàpias Montserrat , Ralló Miquel , Escofet Jaume
Published: December 2015

Fabric openness factor (OF) is the fraction of the web area that is uncovered by yarns.OFis a critical feature regarding the end‐use performance of the fabric and should be accurately assessed. However, digitalOFestimates yielded by image binarization algorithms differ among them depending on the criteria used, mainly due to ill‐defined boundaries, thus precluding a straightforward assessment of the actual fabricOFvalue. Lacking any standard to compare actualOFvalues with measuredOFvalues, we addressed the validation procedure of the digital assessment method from visualOFestimates.OFof 81 distinct fabric samples was evaluated from digital images by a panel of 18 observers using visual binarization technique. Following the psychophysical models of Fechner and Stevens, these visual estimates were correlated with digital estimates yielded by several binarization algorithms. Stevens’ psychophysical model and an automatic binarization algorithm developed by us scored the highest correlation.

Practical Applications

This work addresses the problems that arise at the moment of measuring the area of a region with ill‐defined boundaries without any standard to control the process of measurement. Similar problems are also found in important fields such as medical imaging. In these cases, there are usually different digital methods that give rise to estimates of the magnitude which mismatch among them. To solve these differences, a more common approach is to use estimates provided by a panel of observers and consider them to be objective, regardless of the bias between subjective responses and actual values. However, visual estimates do not show either accuracy (because they are psychophysical measures) or precision (due to the variability among observers). To overcome these difficulties, we propose a procedure to validate a digital method through visual estimates provided by a panel of observers, taking into account the psychophysical models of Fechner and Stevens.
Prediction of Mid‐Urethral Sling Failure with Clinical Findings and Urodynamics
Authors: AYDIN Serdar , ARIOĞLU AYDIN Çağrı , ERSAN Fırat
Published: December 2015

Objective

Mid‐urethral slings (MUS) become a standard, minimally invasive surgery to treat urinary stress incontinence. Our aim is to investigate the contribution of preoperative urodynamics to mid‐urethral slings success and determine predictors for choosing mid‐urethral sling route.

Methods

Women with stress urinary incontinence and who desired surgical correction of their incontinence were included in the study. The selection of the procedure was according to an algorithm used in an institution. Urodynamic and baseline factors that may be associated with surgery failure were analyzed.

Results

A total of 159 patients in the tension free transvaginal tape (TVT) group and 83 patients in the transobturator tape (TOT) group were included in the present study. Urodynamic findings of subjects who were considered MUS failure were not significantly different from those women who were continent after 1 year of surgery. Detrusor overactivity was present on urodynamics in 23 of 37 women (62.2%) with MUS failure, 81 of 205 women (39.7%) with no stress test positivity with the cough stress test (P < 0.05). A vaginal hysterectomy had been performed on 13 of 37 (35.1%) subjects with MUS failure 1 year after operation, and 20 of 205 subjects (9.8%) in the stress urinary incontinence (SUI) continent group (P < 0.001).

Conclusions

Preoperative detrusor overactivity (DO) was the only urodynamic finding that negatively affected the success of surgery in both TOT and TVT groups. Our study demonstrated an increased risk of surgery failure for those who underwent a concurrent hysterectomy for pelvic organ prolapse.
Diet composition of the Eurasian otter Lutra lutra in different freshwater habitats of temperate Europe: a review and meta‐analysis
Authors: Krawczyk Agata Joanna , Bogdziewicz Michał , Majkowska Katarzyna , Glazaczow Adam
Published: December 2015

The Eurasian otter Lutra lutra is a top predator that feeds mostly on fish. Yet, studies show the high plasticity of otter foraging behaviour and the varying importance of alternative food types in the species' diet.

The aims of this study were, firstly, to demonstrate by meta‐analysis how the diet composition of otters varies depending on the habitat occupied, in terms of the types of land use, waterbody, and bank vegetation. Secondly, we tested whether the choice of method of presenting prey percentages in the diet of otters influenced the conclusions of the meta‐analysis.

The percentage of fish in the diet was greater for otters occupying standing water than for those occupying flowing water; was higher for otters in waterbodies overgrown by reed vegetation; and varied depending on the type of surrounding land use. However, the results of the meta‐analysis varied depending on which of the two most common methods of diet analysis were used: percentage biomass or relative frequency of occurrence (RFO).

We showed that the plasticity of otter feeding behaviour might be explained by the various habitats occupied by otters. Habitat differences reflected in otters' diets might have importance for the maintenance and conservation of local populations of this species.

The high diversity of methods used by researchers to report the results of dietary studies precludes full comparisons and synthesis. This demonstrates the importance of unification of reporting. Moreover, the conclusions reached by the authors of any particular study might be highly dependent on the method they applied. Thus, care should be taken when comparing ecological studies based on different methods.
A pseudo‐outbreak of disseminated cryptococcal disease after orthotopic heart transplantation
Authors: Kennedy E. , Vanichanan J. , Rajapreyar I. , Gonzalez B. , Nathan S. , Gregoric I. , Kar B. , Loyalka P. , Weeks P. , Chavez V. , Wanger A. , Ostrosky Zeichner L.
Published: December 2015

Cryptococcal infection is the third most common invasive fungal infection (IFI) among solid‐organ transplant (SOT) recipients and is considered an important opportunistic infection due to its significant morbidity and mortality. To determine whether a cluster of cryptococcosis in heart transplant patients was of nosocomial nature, three cases of orthotopic heart transplant recipients with postoperative disseminated cryptococcal infection were investigated and paired with an environmental survey in a tertiary care hospital. The infection prevention department conducted a multidisciplinary investigation, which did not demonstrate any evidence of health care‐associated environmental exposure. Moreover, multilocus sequence typing showed that one isolate was unique and the two others, although identical, were not temporally related and belong to the most common type seen in the Southern US. Additionally, all three patients had preexisting abnormalities of the CT chest scan and various degrees of acute and chronic rejection. Reactivation was suggested in all three patients. Screening methods may be useful to identify at risk patients and trigger a prophylactic or preemptive approach. However, more data is needed.
Indiana's Property Tax Caps: Old Idea, New Approach, and Surprising Incentives
Authors: Ross Justin M. , Farrell Madeline , Kate Yang Lang
Published: December 2015

Property tax limits are a subject of continual interest among policy makers and scholars, but their implications for overlapping local governments are often unexplored. Indiana recently implemented tax caps that limit individual property tax burdens to a fixed percentage of market value. The resulting system creates structural deficits that depend on the simultaneous spending choices of all overlapping local governments. This paper highlights similarities and differences to other state systems, the many unusual incentives which spring from this system, and some prospects for future public finance research.
Do Troubled Times Invite Cloudy Budget Reporting? The Determinants of General Fund Expenditure Share in U.S. States
Authors: Hudspeth Nancy W. , Merriman David F. , Dye Richard F. , Crosby Andrew W.
Published: December 2015

Fiscal controls require monitoring and transparent reporting. Financial documents with multiple funds, transfers, and inconsistent year‐to‐year categorization of revenues and expenditures provide opportunities to obscure a negative fiscal picture. We hypothesize that fiscal stress increases obfuscation. We investigate the relationship between the share of total governmental expenditures in U.S. states' general funds and independent variables drawn from the literature. Consistent with our hypothesis, deficit and debt are the most important explanatory variables. A one standard deviation increase in the deficit as a share of total expenditures is predicted to decrease the general fund share by one percentage point.
Stable expression of silencing‐suppressor protein enhances the performance and longevity of an engineered metabolic pathway
Authors: Naim Fatima , Shrestha Pushkar , Singh Surinder P. , Waterhouse Peter M. , Wood Craig C.
Published: December 2015

Transgenic engineering of plants is important in both basic and applied research. However, the expression of a transgene can dwindle over time as the plant's small (s)RNA‐guided silencing pathways shut it down. The silencing pathways have evolved as antiviral defence mechanisms, and viruses have co‐evolved viral silencing‐suppressor proteins (VSPs) to block them. Therefore, VSPs have been routinely used alongside desired transgene constructs to enhance their expression in transient assays. However, constitutive, stable expression of a VSP in a plant usually causes pronounced developmental abnormalities, as their actions interfere with endogenous microRNA‐regulated processes, and has largely precluded the use of VSPs as an aid to stable transgene expression. In an attempt to avoid the deleterious effects but obtain the enhancing effect, a number of different VSPs were expressed exclusively in the seeds of Arabidopsis thaliana alongside a three‐step transgenic pathway for the synthesis of arachidonic acid (AA), an ω‐6 long chain polyunsaturated fatty acid. Results from independent transgenic events, maintained for four generations, showed that the VSP‐AA‐transformed plants were developmentally normal, apart from minor phenotypes at the cotyledon stage, and could produce 40% more AA than plants transformed with the AA transgene cassette alone. Intriguingly, a geminivirus VSP, V2, was constitutively expressed without causing developmental defects, as it acts on the siRNA amplification step that is not part of the miRNA pathway, and gave strong transgene enhancement. These results demonstrate that VSP expression can be used to protect and enhance stable transgene performance and has significant biotechnological application.
Effect of insulin‐like growth factor‐I during the early postnatal period in intrauterine growth‐restricted rats
Authors: Ikeda Naho , Shoji Hiromichi , Suganuma Hiroki , Ohkawa Natsuki , Kantake Masato , Murano Yayoi , Sakuraya Koji , Shimizu Toshiaki
Published: December 2015

Background

Insulin‐like growth factor‐I (IGF‐I) is essential for perinatal growth and development; low serum IGF‐I has been observed during intrauterine growth restriction (IUGR). We investigated the effects of recombinant human (rh) IGF‐I in IUGR rats during the early postnatal period.

Methods

Intrauterine growth restriction was induced by bilateral uterine artery ligation in pregnant rats. IUGR pups were divided into two groups injected daily with rhIGF‐I (2 mg/kg; IUGR/IGF‐I, n = 16) or saline (IUGR/physiologic saline solution (PSS), n = 16) from postnatal day (PND) 7 to 13. Maternal sham‐operated pups injected with saline were used as controls (control, n = 16). Serum IGF‐I and IGF binding proteins (IGFBP) 3 and 5 were measured on PND25. The expression of Igf‐i, IGF‐I receptor (Igf‐ir), Igfbp3, and 5 mRNA in the liver and brain was measured using real‐time polymerase chain reaction on PND25. Immunohistochemical staining of the liver for IGF expression was performed.

Results

Mean bodyweight on PND3 and PND25 in the IUGR pups (IUGR/IGF‐I and IUGR/PSS) was significantly lower than that of the control pups. Serum IGF‐I and hepatic Igf‐ir mRNA in the IUGR pups were significantly lower than those in the control pups. In the IUGR/IGF‐I group, hepatic Igfbp3 mRNA and liver immunohistochemical staining were increased. In the IUGR/PSS and control pups, there were no significant differences between these two groups in serum IGFBP3 and IGFBP5, hepatic Igf‐i and Igfbp‐5 mRNA, or brain Igf mRNA.

Conclusions

No benefits on body and brain weight gain but an effective increase in hepatic IGFBP‐3 was observed after treatment with 2 mg/kg rhIGF‐I during the early postnatal period.
The Architecture of Chemical Alternatives Assessment
Authors: Geiser Kenneth , Tickner Joel , Edwards Sally , Rossi Mark
Published: December 2015

Chemical alternatives assessment is a method rapidly developing for use by businesses, governments, and nongovernment organizations seeking to substitute chemicals of concern in production processes and products. Chemical alternatives assessment is defined as a process for identifying, comparing, and selecting safer alternatives to chemicals of concern (including those in materials, processes, or technologies) on the basis of their hazards, performance, and economic viability. The process is intended to provide guidance for assuring that chemicals of concern are replaced with safer alternatives that are not likely to be later regretted. Conceptually, the assessment methods are developed from a set of three foundational pillars and five common principles. Based on a number of emerging alternatives assessment initiatives, in this commentary, we outline a chemical alternatives assessment blueprint structured around three broad steps: Scope, Assessment, and Selection and Implementation. Specific tasks and tools are identified for each of these three steps. While it is recognized that on‐going practice will further refine and develop the method and tools, it is important that the structure of the assessment process remain flexible, adaptive, and focused on the substitution of chemicals of concern with safer alternatives.
Dressing an existential wound (DEW) – a new model for long‐term care following disasters
Authors: Rehnsfeldt Arne , Arman Maria
Published: December 2015

Background

Presence, concern, compassion and universal or ontological unity between human beings have emerged as crucial to the healthy development of people who have experienced disasters.

Aim and objectives

The aim of this article was to present a new model for long‐term care following disasters. The objective of the model was to contribute to the readiness for long‐term care following disasters in professionals and nonprofessionals as a result of their understanding of the model.

Design

A longitudinal qualitative study of Swedish tourists affected by the South East Asian tsunami in 2004 is the empirical base for this clinical model, which was developed within the framework of caring science.

Methods

A hermeneutic method was used.

Results

The model is based on the assumption that life issues are an important aspect of long‐term follow‐up after a disaster. The term ‘life issues’ refers to the following: existential questioning of life's content, values and priorities; people's relationships with each other; and the importance of health, suffering, love and death. Life issues also refer to the way in which survivors form a new understanding of life after a disaster experience. Existential care is based on a charitable attitude of compassion and mercy towards one's fellows, be they professionals, families or wider society. By presenting eight theses, the model provides an approach based on compassion that works as an existential dressing for survivors of disaster.

Conclusions

The model gives a knowledge base and approach for the long‐term care of survivors, including practical advice.
Sociological Approaches to Self‐injury
Authors: Taylor Jim D. , Ibañez Lindsey M.
Published: December 2015

This paper reviews the burgeoning sociological literature on non‐suicidal self‐injury, in which individuals intentionally harm themselves by cutting, burning, scratching, or smashing their body parts. We identify challenges to studying self‐injury, such as conflicting definitions and categorizations. Comparing self‐injury to other behaviors such as suicide, body modification, and self‐mutilation, we assert that non‐suicidal self‐injury deserves its own conceptual category. We explain how a critical sociological approach provides a valuable counterweight to medical and psychological studies of self‐injury. In particular, this paper advances the deviance perspective. Finally, we highlight how technology has allowed self‐injurers to build supportive communities in cyberspace, blurring the line between hidden and public acts. We conclude with suggestions for future directions in the study of self‐injury.
RETROSPECTIVE EVALUATION OF INTERFRACTION URETERAL MOVEMENT IN DOGS UNDERGOING RADIATION THERAPY TO ELUCIDATE APPROPRIATE SETUP MARGINS
Authors: Yoshikawa Hiroto , Nolan Michael W. , Lewis Dustin W. , Larue Susan M.
Published: December 2015

Radiation‐induced ureteral damage can result in serious complications (i.e., hydronephrosis). Also, ureters can be included in planning target volume (PTV) such as ureteral invasion of urinary bladder carcinoma. Therefore, knowing the interfractional movement of the ureters is critical for creation of appropriate planning organs at risk (pOAR) and PTV. This retrospective and descriptive study of 17 dogs with genitourinary carcinomas that underwent intensity‐modulated, image‐guided radiation therapy (IM‐IGRT) was conducted to describe the movement and calculate suggested pOAR/PTV expansions at three locations (at the levels of third lumbar vertebra, immediately cranial to vesicoureteral junction [VUJ], and midway between those two) and from two perspectives: during a course of (1) IM‐IGRT, where position verification is performed using soft tissue registration when the dogs underwent clinical IM‐IGRT; (2) radiation therapy whereby position verification is performed using planar radiography with a corresponding bony registration. This registration was performed by fusing the radiation planning computed tomography (CT) and cone‐beam CTs using bony landmarks. With soft tissue registration, findings supported the use of larger pOAR expansion (0.7–1.8 cm) for the mid region of the ureters compared to the areas near VUJ (0.7–1.1 cm). With bony registration, findings supported the use of larger pOAR/PTV expansions (1.6–1.7 cm) for dorsal direction bilaterally at areas near VUJ compared to those with soft tissue registration (0.9–1.0 cm). The results of this study should help radiation oncologists use appropriate ureter expansions for specific patient orientations and positioning verification methods.
Rigid and remodelled: cerebrovascular structure and function after experimental high‐thoracic spinal cord transection
Authors: Phillips A. A. , Matin N. , Frias B. , Zheng M. M. Z. , Jia M. , West C. , Dorrance A. M. , Laher I. , Krassioukov A. V.
Published: December 2015

Key Points

Spinal cord injury (SCI) is associated with a 3–4 fold increased risk of stroke, and impaired cerebral blood flow regulation, although the effect of SCI on the structure and function of the cerebral arteries is unclear.

Using pressure myography to assess isolated vessels distended at physiological pressures, we provide novel evidence that experimental SCI leads to inward cerebrovascular remodelling, increased stiffness and impaired reactivity of the largest cerebral artery.

Histochemical analyses revealed that a profibrotic environment within the largest cerebral artery occurs after SCI, which was characterized by greater collagen and less elastin. This may be due to increased transforming growth factor β, a well‐known profibrotic signalling protein.

Further analysis revealed that profibrotic alterations were not due to disruption of descending sympathetic pathways to the cerebrovasculature.

Experimental SCI exerts a deleterious influence on the structure and function of cerebral arteries, which may underlie the increased risk of stroke and impaired cerebral blood flow regulation.

High‐thoracic or cervical spinal cord injury (SCI) is associated with several critical clinical conditions related to impaired cerebrovascular health, including: 300–400% increased risk of stroke, cognitive decline and diminished cerebral blood flow regulation. The purpose of this study was to examine the influence of high‐thoracic (T3 spinal segment) SCI on cerebrovascular structure and function, as well as molecular markers of profibrosis. Seven weeks after complete T3 spinal cord transection (T3‐SCI, n = 15) or sham injury (Sham, n = 10), rats were sacrificed for either middle cerebral artery (MCA) structure and function assessments via ex vivo pressure myography, or immunohistochemical analyses. Myogenic tone was unchanged, but over a range of transmural pressures, inward remodelling occurred after T3‐SCI with a 40% reduction in distensibility (both P < 0.05), and a 33% reduction in vasoconstrictive reactivity to 5‐HT trending toward significance (P = 0.09). After T3‐SCI, the MCA had more collagen I (42%), collagen III (24%), transforming growth factor β (47%) and angiotensin II receptor type 2 (132%), 27% less elastin as well as concurrent increased wall thickness and reduced lumen diameter (all P < 0.05). Sympathetic innervation (tyrosine hydroxylase‐positive axon density) and endothelium‐dependent dilatation (carbachol) of the MCA were not different between groups. This study demonstrates profibrosis and hypertrophic inward remodelling within the largest cerebral artery after high‐thoracic SCI, leading to increased stiffness and possibly impaired reactivity. These deleterious adaptations would substantially undermine the capacity for regulation of cerebral blood flow and probably underlie several cerebrovascular clinical conditions in the SCI population.
Functional coupling of diverse voltage‐gated Ca2+ channels underlies high fidelity of fast dendritic Ca2+ signals during burst firing
Authors: Jaafari Nadia , Canepari Marco
Published: December 2015

Key points

In neurons, the Ca2+ signal associated with the dendritic back‐propagating action potential codes a chemical message to the different dendritic sites, playing a crucial role in electrical signalling, synaptic transmission and synaptic plasticity.

The study of the underlying Ca2+ current, mediated by different types of voltage‐gated Ca2+ channels, cannot be achieved by using the patch clamp technique.

In this article, we used a recently developed cutting‐edge optical technique to investigate the physiological behaviour of local Ca2+ currents along the apical dendrite of CA1 hippocampal pyramidal neurons.

We directly measure, for the first time, the synergistic activation and deactivation of the diverse dendritic voltage‐gated Ca2+ channels operating during bursts of back‐propagating action potentials to precisely control the Ca2+ signal.

We demonstrate that the Ca2+ loss via high‐voltage‐activated channels is compensated by the Ca2+ entry via the other channels translating in high fidelity of Ca2+ signalling.

In CA1 hippocampal pyramidal neurons, the dendritic Ca2+ signal associated with somatic firing represents a fundamental activation code for several proteins. This signal, mediated by voltage‐gated Ca2+ channels (VGCCs), varies along the dendrites. In this study, using a recent optical technique based on the low‐affinity indicator Oregon Green 488 BAPTA‐5N, we analysed how activation and deactivation of VGCCs produced by back‐propagating action potentials (bAPs) along the apical dendrite shape the Ca2+ signal at different locations in CA1 hippocampal pyramidal neurons of the mouse. We measured, at multiple dendritic sites, the Ca2+ transients and the changes in membrane potential associated with bAPs at 50 μs temporal resolution and we estimated the kinetics of the Ca2+ current. We found that during somatic bursts, the bAPs decrease in amplitude along the apical dendrite but the amplitude of the associated Ca2+ signal in the initial 200 μm dendritic segment does not change. Using a detailed pharmacological analysis, we demonstrate that this effect is due to the perfect compensation of the loss of Ca2+ via high‐voltage‐activated (HVA) VGCCs by a larger Ca2+ component via low‐voltage‐activated (LVA) VGCCs, revealing a mechanism coupling the two VGCC families of K+ channels. More distally, where the bAP does not activate HVA‐VGCCs, the Ca2+ signal is variable during the burst. Thus, we demonstrate that HVA‐ and LVA‐VGCCs operate synergistically to stabilise Ca2+ signals associated with bAPs in the most proximal 200 μm dendritic segment.
Analysis of responses in visual cells of the leech
Authors: Fioravanti R. , Fuortes M. G. F.
Published: December 2015

1. Potentials were recorded from the cytoplasm and from the vacuole of leech photoreceptors. Since the vacuole is lined with microvilli and is connected to the outside by narrow channels, the potential drops between vacuole and outside measure the current through the microvillar membrane.

2. In darkness, the potential of the cytoplasm with respect to the outside is about — 45 mV while the potential of the vacuole is approximately zero.

3. Following illumination the negativity of the cytoplasm decreases and the vacuole becomes negative relative to the outside.

4. For dim intensities, the response to a flash of light may grow proportionately more than the intensity of the flash. This is probably due to development of a depolarizing local response.

5. The resistance from the cytoplasm to the outside was about 150 MΩ in darkness and decreased to approximately 40 MΩ at the peak of the response to a bright flash (on average). Corresponding measurements from the vacuole gave 50 MΩ in darkness and 35 MΩ at the peak of the response.

6. Charging curves produced by steps of constant currents applied to the cytoplasm or to the vacuole include two time constants (about 5 and 50 msec on average). The longer time constant decreases greatly with bright illumination.

7. The results are consistent with the interpretation that the response to light is brought about by an increase of conductance of the microvillar membrane.
Membrane potentials of epithelial cells in rat small intestine
Authors: Barry R. J. C. , Eggenton Jacqueline
Published: December 2015

1. Stripped sacs of rat jejunum in which the outer muscle layers had been removed were found to maintain substantial transport and electrical activities.

2. Mucosal and serosal membrane potentials of epithelial cells of normal and stripped everted sacs of rat jejunum were recorded in vitro together with the transmural potential difference.

3. The cell interior was negative relative to both serosal and mucosal fluids, the transmural potential being the sum of the two membrane potentials.

4. Changes in the transmural potentials in the presence of actively transferred hexoses and amino acids were entirely due to variations in the serosal potential, the mucosal potential being unchanged.

5. Serosal and transmural potential increases on the addition of galactose were consistent with Michaelis—Menten kinetics, giving apparent Km values of 14·9 and 14·1 m
M respectively.

6. Phlorrhizin, ouabain, 2,4‐dinitrophenol and sodium fluoroacetate inhibited serosal potential changes in the presence of galactose.

7. Osmotic potentials resulting from transmural osmotic gradients originated from the serosal layers of the tissue.

8. The results are consistent with the concept of a serosally located, electrogenic sodium pump which is stimulated by actively transferred hexoses and amino acids. The sodium‐dependent entry mechanism at the mucosal membrane is non‐electrogenic.
Elementos para discusión sobre el estado actual de la propuesta curricular del programa de contaduría pública de la Universidad de Antioquia
Authors: Duque Roldán María Isabel , Ospina Zapata Carlos Mario
Published: December 2015

El programa de contaduría de la Universidad de Antioquia declara expresamente la utilización de un modelo pedagógico que combina elementos sociales y desarrollistas, para lo cual se configuró un diseno curricular basado en la solucion de problemas, en el cual se contextualizan y problematizan todos aquellos asuntos que son relevantes en la formación del contador público en Colombia. Este enfoque requiere: 1) la utilización de didácticas activas para que el estudiante se apropie del conocimiento de manera consciente, crítica y reflexiva y no se ejerza una mera transmisión de contenidos o normas y 2) la investigación como eje articulador, como camino que enriquece el trabajo que se hace en el aula. Este artículo presenta parte de los resultados de una investigación cualitativa que tiene como objetivo determinar el cumplimiento de los fundamentos conceptuales de la transformación curricular del programa y la cual combinó la indagación directa a los estudiantes y el análisis de los microcurrículos elaborados por los profesores y de sus prácticas en el aula. El trabajo realizado permite concluir que las didácticas utilizadas en su mayoría resultan propias de modelos pedagógicos instruccionales o tradicionales, que la investigación no ha logrado permear completamente la labor realizada en el aula y que diversos componentes de la propuesta se quedan a medio camino en su ejecutoria. Esto sin desconocer que se han logrado avances importantes en la formación de contadores públicos.  
Principio de favorabilidad de las normas sustantivas en materia tributaria. Choque de trenes entre la Corte Constitucional y el Consejo de Estado
Authors: Restrepo Pineda Carlos Mario
Published: December 2015

En el derecho administrativo especial tributario, la norma sustantiva se refiere a los elementos estructurales del tributo: el sujeto pasivo, el sujeto activo, el hecho generador, la base gravable y la tarifa. El principio de favorabilidad de las normas sustantivas en materia tributaria, referente a impuestos de período, se entiende como la aplicación de las normas sustantivas que disminuyen o eliminan las cargas tributarias siendo favorable al contribuyente, en el mismo período fiscal en que entró en vigencia la norma. La forma como está redactado el inciso tercero del artículo 338 de la Constitución al interpretarlo en armonía con el inciso segundo del artículo 363 constitucional genera confusiones o disyuntivas en cuanto a la aplicación de este principio. El presente artículo tiene como objetivo puntualizar la línea jurisprudencial de la Corte Constitucional y del Consejo de Estado con el fin de hacer un análisis comparativo acerca de la aplicación del principio de favorabilidad de las normas sustantivas en el derecho tributario.

La línea jurisprudencial de cada una de estas dos Corporaciones se ha construido siguiendo la metodología propuesta por Diego Eduardo López-Medina, que consiste en hacer una pregunta orientadora. En este caso: ¿aplica el principio de favorabilidad de las normas sustantivas en materia tributaria? Con dos polos de respuesta —sí y no—, para el efecto se tomó el lapso que va de 1993 a 2014, en el que se rastrearon las sentencias de ambas corporaciones, se identificó la sentencia más reciente denominada sentencia arquimédica. Luego, mediante las citas de la sentencia, se fueron detectando otras sentencias referentes al mismo tema, hasta llegar a la sentencia fundante de la línea; entre los dos extremos —la sentencia arquimédica y la sentencia fundante—, quedaron las demás sentencias organizadas cronológicamente. Después, luego se observó qué resultado se obtuvo, que puede ser una línea coherente o una línea caótica (López-Medina, 2000, pp. 142-147). En el caso del Consejo de Estado se encontraron 18 sentencias, y en el de la Corte Constitucional, 15 sentencias. Este artículo presenta la línea jurisprudencial de la Corte Constitucional y del Consejo de Estado, junto con los hallazgos, conclusiones y recomendaciones alrededor del tema.
Du reclamation act de 1902 aux megaprojets federaux. Une perspective sociohistorique sur la genèse des politiques hydriques aux USA: le cas de l’Ouest étasunien
Authors: Cortinas Muñoz Joan , Coeurdray Murielle , Poupeau Franck
Published: December 2015

Cet article se propose d’apporter un éclairage aux problèmes de pénurie d’eau que vit actuellement l’ouest des Etats-Unis. A travers un travail de reconstitution historique des politiques hydriques de la région, l’article défend l’idée que la pénurie d’eau actuelle doit se comprendre, en partie, comme le résultat de l’action des élites économiques, politiques et administratives qui ont conçu les politiques hydriques aux USA. Plus concrètement, la pénurie d’eau, au-delà du cycle de sécheresse actuel, est le résultat de la production d’une vision du développement économique traversée par des intérêts et des logiques contradictoires relatifs à l’exploitation des ressources naturelles, largement conçue comme un facteur déterminant de croissance.
Heat Pump Water Heater Control Strategy Optimization for Cold Climates
Authors: Bursill Jayson , Cruickshank Cynthia A.
Published: December 2015

This paper presents a study which was conducted to evaluate the performance of a commercially available heat pump water heater (HPWH) with modified controls. The HPWH is first characterized experimentally under a series of different thermal conditions and draw parameters. The test tank contains a 1500 W electric auxiliary heater that provides on demand heat to the top 0.30 m (1 ft) of the tank, and a wrap-around heating coil. An air source heat pump (ASHP), using R-134A as the refrigerant, draws air from, and returns air to the surrounding space and provides heating to the whole tank through the coil. The tank has been tested using Canadian Standards Association draw profiles to characterize performance under different hot water demands. Electricity consumption and thermal flux is measured for each vertical tank section, and various performance metrics are calculated using energy balances. A trnsys model is then calibrated to the experimental data to allow for the flexibility of varying multiple parameters over various climates. Using this calibrated trnsys model, an optimal control strategy and tank setpoints can be determined for use in cold climates. As expected from previous work, there is a decrease in performance of the HP when heating the tank to higher temperatures to facilitate thermal storage, but the benefits from taking advantage of shifting electrical demand (of water heating) to space heating demand can outweigh the loss of performance.
Development of New Critical Heat Flux Correlation for Microchannel Using Energy-Based Bubble Growth Model
Authors: Kumar Ritunesh , Kadam Sambhaji T.
Published: December 2015

Critical heat flux (CHF) is a key design consideration for the systems involving heat dissipation through boiling application. It dictates the maximum limit of performance of heat transfer systems. Abrupt and substantial decrease in heat transfer coefficient is an indirect indication of occurrence of the CHF, which may cause complete burnout of heat transfer surface. Unlike conventional channels, CHF correlations for microchannels are limited and associated with significant variations. In the present paper, effort has been made to develop new CHF models applicable to a frequently occurring scenario of flow boiling in microchannels. The approach combines nondimensional analysis and an energy analysis based bubble growth model at an arbitrary nucleation site. Two separate CHF correlations for refrigerants and water have been developed following a semi-empirical approach. The proposed correlations show good agreement with available experimental data. The mean errors for the refrigerant and water cases are, respectively, found to be 21% and 27% for seven and six relevant datasets. Around 77% data of the refrigerant and 60% data of water are predicted within error band of ±30%. It is also found that influence of a certain energy ratio term (gravity to surface tension, denoted as πE4) is negligible for examined water CHF conditions.
Cooling of a Hot Torus
Authors: Alassar Rajai S. , Abushoshah Mohammed A.
Published: December 2015

The problem of a hot torus left to cool in a medium of known temperature is studied. We write the governing equation in toroidal coordinates and expand the temperature in terms of a series in the angular direction. The resulting modes in the radial direction are numerically obtained. We consider both isothermal and convective boundary conditions and study the effect of Biot number and aspect ratio on the heat transfer rate.
Pacing Behavior and Tactical Positioning in 500- and 1000-m Short-Track Speed Skating
Authors: Noorbergen Olaf S. , Konings Marco J. , Micklewright Dominic , Elferink-Gemser Marije T. , Hettinga Florentina J.
Published: December 2015

Purpose:

To explore pacing behavior and tactical positioning during the shorter 500- and 1000-m short-track competitions.

Methods:

Lap times and intermediate rankings of elite 500- and 1000-m short-track-skating competitors were collected over the 2012–13 season. First, lap times were analyzed using a MANOVA, and for each lap, differences between sex, race type, final ranking, and stage of competition were determined. Second, Kendall tau-b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined.

Results:

Top-placed athletes appeared faster than bottom-placed athletes in every lap in the 500-m, while in the 1000-m no differences were found until the final 4 laps (P < .05). Correlations between intermediate and final rankings were already high at the beginning stages of the 50-m (lap 1: r = .59) but not for the 1000-m (lap 1: r = .21).

Conclusions:

Although 500- and 1000-m short-track races are both relatively short, fundamental differences in pacing behavior and tactical positioning were found. A fast-start strategy seems to be optimal for 500-m races, while the crucial segment in 1000-m races seems to be from the 6th lap to the finish line (ie, after ± 650 m). These findings provide evidence to suggest that athletes balance between choosing an energetically optimal profile and the tactical and positional benefits that play a role when riding against an opponent, as well as contributing to developing novel insights in exploring athletic behavior when racing against opponents.
Ecological Validity and Reliability of the Rugby Sevens Simulation Protocol
Authors: Furlan Nicola , Waldron Mark , Osborne Mark , Gray Adrian J.
Published: December 2015

Purpose:

To assess the ecological validity of the Rugby Sevens Simulation Protocol (R7SP) and to evaluate its interday reliability.

Methods:

Ten male participants (20 ± 2 y, 74 ± 11 kg) completed 2 trials of the R7SP, separated by 7 d. The R7SP comprised typical running and collision activities, based on data recorded during international rugby sevens match play. Heart rate (HR) was monitored continuously during the R7SP, and the participants’ movements were recorded through a 20-Hz global positioning system unit. Blood lactate and rating of perceived exertion were collected before and immediately after the 1st and 2nd halves of the R7SP.

Results:

The average activity profile was 117 ± 5 m/min, of which 27 ± 2 m/min was covered at high speed, with a calculated energetic demand of 1037 ± 581 J/kg, of which ~40% was expended at a rate above 19 W/kg. Mean HR was 88% ± 4% of maximal HR. Participants spent ~45% ± 27% of time above 90% of maximal HR (t >90%HRmax). There were no significant differences between trials, except for lactate between the halves of the R7SP. The majority of the measured variables demonstrated a between-trials coefficient of variation (CV%) lower than 5%. Blood lactate measurements (14–20% CV) and t >90%HRmax (26% CV) were less reliable variables. In most cases, the calculated moderate worthwhile change was higher than the CV%.

Conclusions:

The R7SP replicates the activity profile and HR responses of rugby sevens match play. It is a reliable simulation protocol that can be used in a research environment to detect systematic worthwhile changes in selected performance variables.