bluuebunny/crossref_metadata_2025 huggingface dataset:
Ypk1, the yeast orthologue of the human serum- and glucocorticoid-induced kinase, is required for efficient uptake of fatty acids
Authors: Jacquier Nicolas , Schneiter Roger
Published: June 2010

Fatty acids constitute an important energy source for various tissues. The mechanisms that mediate and control uptake of free fatty acids from the circulation, however, are poorly understood. Here we show that efficient fatty-acid uptake by yeast cells requires the protein kinase Ypk1, the orthologue of the human serum- and glucocorticoid-induced kinase Sgk1. ypk1Δ mutant cells fail to grow under conditions that render cells auxotrophic for fatty acids, show a reduced uptake of radiolabelled or fluorescently labelled fatty acids, lack the facilitated component of the uptake activity, and have elevated levels of fatty acids in a bovine serum albumin (BSA) back-extractable compartment. Efficient fatty-acid uptake and/or incorporation requires the protein-kinase activity of Ypk1, because a kinase-dead point-mutant allele of YPK1 is defective in this process. This function of Ypk1 in fatty-acid uptake and/or incorporation is functionally conserved, because expression of the human Sgk1 kinase rescues ypk1Δ mutant yeast. These observations suggest that Ypk1 and possibly the human Sgk1 kinase affect fatty-acid uptake and thus energy homeostasis through regulating endocytosis. Consistent with such a proposition, mutations that block early steps of endocytosis display reduced levels of fatty-acid uptake.
Cytokinesis proteins Tum and Pav have a nuclear role in Wnt regulation
Authors: Jones Whitney M. , Chao Anna T. , Zavortink Michael , Saint Robert , Bejsovec Amy
Published: June 2010

Wg/Wnt signals specify cell fates in both invertebrate and vertebrate embryos and maintain stem-cell populations in many adult tissues. Deregulation of the Wnt pathway can transform cells to a proliferative fate, leading to cancer. We have discovered that two Drosophila proteins that are crucial for cytokinesis have a second, largely independent, role in restricting activity of the Wnt pathway. The fly homolog of RacGAP1, Tumbleweed (Tum)/RacGAP50C, and its binding partner, the kinesin-like protein Pavarotti (Pav), negatively regulate Wnt activity in fly embryos and in cultured mammalian cells. Unlike many known regulators of the Wnt pathway, these molecules do not affect stabilization of Arm/β-catenin (βcat), the principal effector molecule in Wnt signal transduction. Rather, they appear to act downstream of βcat stabilization to control target-gene transcription. Both Tum and Pav accumulate in the nuclei of interphase cells, a location that is spatially distinct from their cleavage-furrow localization during cytokinesis. We show that this nuclear localization is essential for their role in Wnt regulation. Thus, we have identified two modulators of the Wnt pathway that have shared functions in cell division, which hints at a possible link between cytokinesis and Wnt activity during tumorigenesis.
Peramivir: An Intravenous Neuraminidase Inhibitor for the Treatment of 2009 H1N1 Influenza
Authors: Mancuso Carissa E , Gabay Michael P , Steinke Leah M , Vanosdol Sherilyn J
Published: June 2010

Objective:

To review the efficacy and safety of peramivir, an unapproved neuraminidase inhibitor recently granted an Emergency Use Authorization (EUA) by the Food and Drug Administration (FDA) for the treatment of 2009 H1N1 influenza in select patients.

Data Sources:

Literature was accessed via MEDLINE (1950–April 2010) using the search terms peramivir, BCX-1812, RWJ 270201, influenza H1N1, swine influenza, and neuraminidase inhibitors. The manufacturer of peramivir, BioCryst Pharmaceuticals, was contacted for unpublished data and information presented at recent scientific meetings. Information was obtained from the Centers for Disease Control and Prevention (CDC) and FDA Web sites. The mandatory requirements for the EUA for peramivir were also consulted.

Study Selection and Data Extraction:

Available English-language literature was reviewed and selected based on relevance, as was information from the CDC, FDA, and the drug manufacturer.

Data Synthesis:

The 2009 H1N1 influenza pandemic has necessitated the selective use of intravenous peramivir, an unapproved neuraminidase inhibitor. Intravenous peramivir has been studied in 4 clinical trials, 2 of which compared the drug to oseltamivir. Dose adjustments are required in pediatric patients and in those with impaired renal function. Clinicians wishing to use peramivir must request authorization from the CDC to confirm patient characteristics warranting its use and to verify the prescriber's understanding of dosing considerations and unapproved status.

Conclusions:

Peramivir has shown efficacy for the treatment of 2009 H1N1 influenza; however, it has yet to receive FDA approval. Peramivir is used in hospitalized adult and pediatric patients with suspected or laboratory-confirmed 2009 H1N1 influenza meeting specific criteria, including those unable to receive inhaled or oral neuraminidase inhibitors, those who have not responded to other neuraminidase inhibitors, or when drug delivery by a route other than intravenous is not feasible.
Training bodies to matter
Authors: Albright Ann Cooper
Published: June 2010

This essay traces three different pedagogical situations in which I try to shift what I see as the negative corporeal dynamics of our contemporary moment, one body at a time. Drawing examples from my experiences with the body-to-body interactions of Contact Improvisation, the dance
form that first brought me into dance thirty years ago; Bridging the Body/Mind Divide, a first-year seminar taught to a general range of students at Oberlin College in Ohio, USA; and Girls in Motion, the after-school programme I run for adolescent girls at a local school, I present examples
of skills that I believe create an important somatic foundation for a more mindful being-in-the-world. In these examples of corporeal rhetorics, I consciously harness the persuasive force of movement experiences to convince my students there is a better way to dwell in their bodies and in
this twenty-first-century world.
Towards an innovative model of teaching Greek traditional dances
Authors: Barboussi Vasso , Vidali Anna
Published: June 2010

This article describes an experiential qualitative research project related to dance education, in which the authors examine the effect of teaching Greek traditional dances to a group of students in a Preschool Teachers' Education department. The research process focuses on methodologies
that can support Preschool Education students (future teachers) to utilize embodied-creative practices in learning traditional dances and, thus, to expand their views about culture as well. We would like to argue that dance education could be a means of self-knowledge, which contributes to
self-development. This goal is approached by using an innovative model, which applies somatics along with creative dance methods in order to support students to explore traditional dance through movement improvisation. We also suggest that somatic practices are not to be considered as natural
but culturally specific and developing in particular contexts. Indeed the findings illustrate that the practice gave students competence in involving themselves in a dialogue, through which they gained self-awareness in dance practice, they realized changes in body/mind perceptions and became
confident both about their bodies and their cultural identity. The text is divided into the following sections: introduction, the aim of the study, the methodology of the study, findings, further considerations on the cultural construction of body movement, and epilogue.
Evolving discourses on design thinking: how design cognition inspires meta-disciplinary creative collaboration
Authors: Lindberg Tilmann , Noweski Christine , Meinel Christoph
Published: June 2010

Originating within research on design cognition, the term design thinking has been growing in popularity over the past three decades, and has become a matter in a variety of discourses, assuming diverse and not necessarily congruent notions. In this article we suggest how to differentiate
those discourses on design thinking and discuss its evolution into a meta-disciplinary concept.
Physical Entropy in Computer Games
Authors: Schiffler Andreas
Published: June 2010

Digital computers are by design completely deterministic, yet they are often consumers of randomness in cryptography, simulations, science experiments and computer games. To generate randomness in software, programmers implement special mathematical algorithms, which produce a series
of numbers that appear nondeterministic, so called pseudo random number generators (PRNGs). Computer games make heavy use of such PRNGs to make game simulations and behaviors of game elements appear more natural. An important design element of many video games is game physics, the simulation
of physical reality in video games. Generally overlooked by game developers, is the fact that randomness based on PRNGs are mere simulations themselves and randomness is not treated as a physical property of reality, and thus a form of game physics. Since the dynamics of the very small and
the very complex invariably contains randomness, the author suggests this can be used to extend to the scope of game physics by defining two new game physics elements: 1. providing physics based random data to games or interactive media and 2. extracting true randomness from game-player interactions
themselves.
Wearable artefacts as research vehicles
Authors: Beloff Laura
Published: June 2010

The wearable technology field, including terms and areas such as wearable computing and fashionable technology, has been evolving at the cross-section of various disciplines including science, technology, arts, augmented reality, design, cybernetics, ergonomics and fashion. As an example, the research community in wearable computing has been carrying out profound work in understanding and defining many key principles in the field. According to these researchers, the wearable computer is understood as a kind of extension of the body, which enables it to perform tasks that would not otherwise be possible, such as being in several places at the same time.1This is an example of one of the approaches currently existing in this multifaceted field. The field also contains other detectable approaches, each with their own distinct aim. These approaches vary from developing solutions to engineering problems to developments in fashion and design and further to more conceptual approaches in addressing the field with what the author refers to as a playful attitude. When one investigates various projects in the wearable field more closely one can detect at least three clearly distinct approaches. The first approach is to follow the general guidelines for wearable computing development and objectives defined during the 1990s. The second approach sometimes called fashionable technology, to some extent follows similar directives as the first approach, but, in addition, it is strongly related to traditions and expectations in the areas of fashion and textile. The third approach has self-defined aims, which are partially contradictory to the general goals prevailing in the field. This third approach has been left almost without a notice in publications emerging from the field as well as in other theoretical writings concerned of art and technology. Until now the wearable technology field has been discussed primarily as one unified area striving towards similar goals.

This article investigates this third approach. It asks how and why some of the projects in the field seem to differ from the general goals persisting in the field, and examines what the possible motivations and intentions behind this alternative approach are. Lastly, the article introduces the Hybronaut as a concept related to the author's practice and research.
Frames from the life and death of Jean Charles de Menezes
Authors: Bianchi Amos
Published: June 2010

This article is a theoretical enquiry about the death of the Brazilian citizen Jean Charles de Menezes, shot in London at Stockwell tube station on 22 July 2005 by unknown specialist firearms' officers. The previous day some stations of the Tube were struck by failed bombing attacks.
The police were chasing four suspects. Some hours after the murder, de Menezes was discovered to be innocent and not involved in the terrorist act.
Evolutionary design and the economy of discourse
Authors: Bck Ingrid
Published: June 2010

Combining genetic algorithms that produce complex, fluid, biomorphic shapes with probabilistic systems that incorporate randomness, the designers attempt to mimic adaptive systems in natural evolution in order to arrive at intelligent design solutions. The design processes are said to be interactive and sensitive to varying conditions, behaving like an exceptionally perceptive and adaptive organism during an evolutionary process (Somol 2004: 8687); this process can be compared to the recent attempt by the architectural avant-garde to move beyond the semiotic interests of deconstructionism and tap into the authority of the natural sciences. In some sense, an analogy can be drawn to natural evolution. In the natural world, adaptation and change result from an iterative progress, from one generation to the next, driven by mutation, recombination, and the survival of the fittest in the sense of selection. Following the model of nature in architecture, as proposed by some proponents of parametricism, should not be expected to make buildings more precisely adapted to particular circumstances and optimally functional. Evolutionary theory is used in contemporary architecture as a form of legitimization. It can also cast light on ethical issues, not reducing the human mind's creative intelligence to some sort of genetic determinism, developing in the free market of social choice. Therefore, searching for better ways of managing resources should be at the core of an adaptive concept of architecture.
LRRTMs and Neuroligins Bind Neurexins with a Differential Code to Cooperate in Glutamate Synapse Development
Authors: Siddiqui Tabrez J. , Pancaroglu Raika , Kang Yunhee , Rooyakkers Amanda , Craig Ann Marie
Published: June 2010

Leucine-rich repeat transmembrane neuronal proteins (LRRTMs) were recently found to instruct presynaptic and mediate postsynaptic glutamatergic differentiation. In a candidate screen, here we identify neurexin-1β lacking an insert at splice site 4 (−S4) as a ligand for LRRTM2. Neurexins bind LRRTM2 with a similar affinity but distinct code from the code for binding neuroligin-1 (the predominant form of neuroligin-1 at glutamate synapses, containing the B splice site insert). Whereas neuroligin-1 binds to neurexins 1, 2, and 3 β but not α variants, regardless of insert at splice site 4, LRRTM2 binds to neurexins 1, 2, and 3 α and β variants specifically lacking an insert at splice site 4. We further show that this binding code is conserved in LRRTM1, the family member linked to schizophrenia and handedness, and that the code is functional in a coculture hemisynapse formation assay. Mutagenesis of LRRTM2 to prevent binding to neurexins abolishes presynaptic inducing activity of LRRTM2. Remarkably, mutagenesis of neurexins shows that the binding face on neurexin-1β (−S4) is highly overlapping for the structurally distinct LRRTM2 and neuroligin-1 partners. Finally, we explore here the interplay of neuroligin-1 and LRRTM2 in synapse regulation. In neuron cultures, LRRTM2 is more potent than neuroligin-1 in promoting synaptic differentiation, and, most importantly, these two families of neurexin-binding partners cooperate in an additive or synergistic manner. Thus, we propose a synaptic code hypothesis suggesting that neurexins are master regulators of the cooperative activities of LRRTMs and neuroligins.
Grueneberg Ganglion Neurons Are Finely Tuned Cold Sensors
Authors: Schmid Andreas , Pyrski Martina , Biel Martin , Leinders-Zufall Trese , Zufall Frank
Published: June 2010

The Grueneberg ganglion is a newly appreciated nasal subsystem with neural connections to the olfactory forebrain, but its functional role has not been well defined. Here, we assess whether Grueneberg ganglion neurons (GGNs) function as thermosensors. By investigating the effect of acute temperature changes on the cytosolic Ca2+concentration of genetically labeled mouse GGNs (either gender), we demonstrate that GGNs are thermosensory neurons specialized to detect a temperature decline within a given temperature window. Furthermore, GGNs comprise a relatively homogeneous cell population with respect to temperature sensitivity. GGNs do not respond to ligands of the temperature-sensitive TRP channels TRPM8 and TRPA1, suggesting a novel mechanism for temperature sensing. One possibility is a cGMP-mediated mechanism, as GGNs express the receptor guanylyl cyclase GC-G, the cGMP-sensitive phosphodiesterase PDE2 and the cGMP-sensitive channel CNGA3. Surprisingly,Cnga3-null mice show normal cooling-induced Ca2+responses although cGMP-dependent Ca2+increases are absent in these mice. Rather, the cooling-induced Ca2+response of GGNs depends critically on the activity of a tetrodotoxin-sensitive voltage-gated sodium channel whereas the cGMP-dependent Ca2+signal does not. These findings establish the Grueneberg ganglion as a sensory organ mediating cold-evoked neural responses, possibly in conjunction with the sensing of other stress- or fear-related chemical social cues.
Early Stress Is Associated with Alterations in the Orbitofrontal Cortex: A Tensor-Based Morphometry Investigation of Brain Structure and Behavioral Risk
Authors: Hanson Jamie L. , Chung Moo K. , Avants Brian B. , Shirtcliff Elizabeth A. , Gee James C. , Davidson Richard J. , Pollak Seth D.
Published: June 2010

Individuals who experience early adversity, such as child maltreatment, are at heightened risk for a broad array of social and health difficulties. However, little is known about how this behavioral risk is instantiated in the brain. Here we examine a neurobiological contribution to individual differences in human behavior using methodology appropriate for use with pediatric populations paired with an in-depth measure of social behavior. We show that alterations in the orbitofrontal cortex among individuals who experienced physical abuse are related to social difficulties. These data suggest a biological mechanism linking early social learning to later behavioral outcomes.
Extracellular Signal-Regulated Kinase-2 within the Ventral Tegmental Area Regulates Responses to Stress
Authors: Iñiguez Sergio D. , Vialou Vincent , Warren Brandon L. , Cao Jun-Li , Alcantara Lyonna F. , Davis Lindsey C. , Manojlovic Zarko , Neve Rachael L. , Russo Scott J. , Han Ming-Hu , Nestler Eric J. , Bolaños-Guzmán Carlos A.
Published: June 2010

Neurotrophic factors and their signaling pathways have been implicated in the neurobiological adaptations in response to stress and the regulation of mood-related behaviors. A candidate signaling molecule implicated in mediating these cellular responses is the extracellular signal-regulated kinase (ERK1/2), although its functional role in mood regulation remains to be fully elucidated. Here we show that acute (1 d) or chronic (4 weeks) exposure to unpredictable stress increases phosphorylation of ERK1/2 and of two downstream targets (ribosomal S6 kinase and mitogen- and stress-activated protein kinase 1) within the ventral tegmental area (VTA), an important substrate for motivated behavior and mood regulation. Using herpes simplex virus-mediated gene transfer to assess the functional significance of this ERK induction, we show that overexpressing ERK2 within the VTA increases susceptibility to stress as measured in the forced swim test, responses to unconditioned nociceptive stimuli, and elevated plus maze in Sprague Dawley male rats, and in the tail suspension test and chronic social defeat stress procedure in C57BL/6 male mice. In contrast, blocking ERK2 activity in the VTA produces stress-resistant behavioral responses in these same assays and also blocks a chronic stress-induced reduction in sucrose preference. The effects induced by ERK2 blockade were accompanied by decreases in the firing frequency of VTA dopamine neurons, an important electrophysiological hallmark of resilient-like behavior. Together, these results strongly implicate a role for ERK2 signaling in the VTA as a key modulator of responsiveness to stress and mood-related behaviors.
Spinal Matrix Metalloproteinase-9 Contributes to Physical Dependence on Morphine in Mice
Authors: Liu Wen-Tao , Han Yuan , Liu Yue-Peng , Song Angela A. , Barnes Beth , Song Xue-Jun
Published: June 2010

Preventing and reversing opioid dependence continues to be a clinical challenge and underlying mechanisms of opioid actions remain elusive. We report that matrix metalloproteinase-9 (MMP-9) in the spinal cord contributes to development of physical dependence on morphine. Chronic morphine exposure and naloxone-precipitated withdrawal increase activity of spinal MMP-9. Spinal inhibition or targeted mutation of MMP-9 suppresses behavioral signs of morphine withdrawal and the associated neurochemical alterations. The increased MMP-9 activity is mainly distributed in the superficial dorsal horn and colocalized primarily with neurons and small numbers of astrocytes and microglia. Morphine exposure and withdrawal increase phosphorylation of NR1 and NR2B receptors, ERK1/2, calmodulin-dependent kinase II, and cAMP response element binding proteins; and such phosphorylation is suppressed by either spinal inhibition or targeted mutation of MMP-9. Further, spinal administration of exogenous MMP-9 induces morphine withdrawal-like behavioral signs and mechanical allodynia, activates NR1 and NR2 receptors, and downregulates integrin-β1, while a function-neutralizing antibody against integrin-β1 suppresses MMP-9-induced phosphorylation of NR1 and NR2B. Morphine withdrawal-induced MMP-9 activity is also reduced by an nNOS inhibitor. Thus, we hypothesize that spinal MMP-9 may contribute to the development of morphine dependence primarily through neuronal activation and interaction with NR1 and NR2B receptors via integrin-β1 and NO pathways. The other gelatinase, MMP-2, is not involved in morphine dependence. Inhibiting spinal MMP-9 or MMP-2 reduces chronic and/or acute morphine tolerance. This study suggests a novel therapeutic approach for preventing, minimizing, or reversing opioid dependence and tolerance.
A General Factor of Brain White Matter Integrity Predicts Information Processing Speed in Healthy Older People
Authors: Penke Lars , Maniega Susana Muñoz , Murray Catherine , Gow Alan J. , Valdés Hernández Maria C. , Clayden Jonathan D. , Starr John M. , Wardlaw Joanna M. , Bastin Mark E. , Deary Ian J.
Published: June 2010

Human white matter integrity has been related to information processing speed, but it is unknown whether impaired integrity results from localized processes or is a general property shared across white matter tracts. Based on diffusion MRI scans of 132 healthy individuals with a narrow age range around 72 years, the integrity of eight major white matter tracts was quantified using probabilistic neighborhood tractography. Principal component analyses (PCAs) were conducted on the correlations between the eight tracts, separately for four tract-averaged integrity parameters: fractional anisotropy, mean diffusivity, and radial and axial diffusivity. For all four parameters, the PCAs revealed a single general factor explaining ∼45% of the individual differences across all eight tracts. Individuals' scores on a general factor that captures the common variance in white matter integrity had significant associations with a general factor of information processing speed for fractional anisotropy (r= −0.24,p= 0.007) and radial diffusivity (r= 0.21,p= 0.016), but not with general intelligence or memory factors. Individual tracts showed no associations beyond what the common integrity factor explained. Just as different types of cognitive ability tests share much of their variance, these novel findings show that a substantial amount of variance in white matter integrity is shared between different tracts. Therefore, impaired cortical connection is substantially a global process affecting various major tracts simultaneously. Further studies should investigate whether these findings relate more to the role of tract integrity and information processing speed in nonpathological cognitive aging or in lifelong-stable processes.
Gender Differences in the Discourse of Greek Children Play-Groups
Authors: Georgalidou Marianthi
Published: June 2010

This paper examines the discourse of children of nursery school age concerning the construction of gender. It focuses on the conversational negotiation of control acts - i.e. conversational moves which attempt to change the behaviour of others-, and the use of politeness – i.e. strategies for the protection of face- in connection to the sex of the children, the type of the activity, and the composition of the play-group. The data are part of the corpus of a larger study, which examines the use of control acts by children of nursery school age (Author 2001). It is based on ethnographic observations of children’s activities in the nursery school environment that lasted one school year. The children involved are of both sexes and of various social backgrounds. The conversational exchanges used for the present study are based on recordings that took place during playtime activities. Transcripts of topically similar interactions have been selected so as the discourse of single- and mixed-sex groupings to be studied and juxtaposed. Based on the analysis, it will be claimed that Greek children of both sexes make use of linguistic markers of dominance in their choice of control acts which, rather than being linked to the sex of the speakers, are linked to one’s achieved position of power within the play-group, as has already been shown in other studies (Goodwin 2001).
Butch camp
Authors: Koller Veronika
Published: June 2010

This paper analyses an article (Gulston 1980) that constructs a particular lesbian identity position by combining elements of female masculinity/butchness with a camp stance usually attributed to gay men. Beyond the text itself, the analysis also addresses how the article, which was published in a British feminist magazine in 1980, sets this identity in opposition to prevailing discourses on lesbian identity at that historical moment. More generally, the paper is intended to contribute to a data-driven discussion that links claims about the relations between language, gender and sexuality back to concrete textual evidence. Drawing on the discourse-historical approach (Wodak 2002), the analysis includes parameters such as social actors, evaluation, metaphor, as well as intertextuality and interdiscursivity. It shows how the author draws on earlier discourses and practices by setting up 1950s-style butches and femmes as social actor groups, while ironically alluding to 1970s lesbian feminist who criticised lesbian genders as an emulation of oppressive heterosexuality. Irony is a predominant feature in the text, realised by metaphors that draw on biologist notions of gender (e.g. BUTCHES ARE AN ENDANGERED SPECIES), and by extreme hypotaxis mimicking archaic speech styles. Apart from irony, the text also shows other features of ‘camp talk’ (Harvey 2000) such as innuendo, Latinate terms, or hyperbole. The text constructs a hybrid butch/camp identity while ironically drawing on essentialist notions of gender and sexuality, and can therefore be regarded as an early instance of queer discourse. How the author parodies and exaggerates lesbian feminist notions of butch/femme as a bygone 1950s cliché shows her as being ahead of her time. An analysis of her text is thus highly relevant for present-day scholars of language, gender and sexuality.
Modeling predicts that redd trampling by cattle may contribute to population declines of native trout
Authors: Peterson Douglas P. , Rieman Bruce E. , Young Michael K. , Brammer James A.
Published: June 2010

Unrestricted livestock grazing can degrade aquatic ecosystems, and its effects on native vertebrate species are generally mediated by changes to physical habitat. Recently, high estimated rates of cattle trampling on artificial redds within federal grazing allotments in southwestern Montana, USA, has raised concern that direct mortality from trampling may contribute to imperilment of native westslope cutthroat trout (Oncorhynchus clarkii lewisi). To explore the implications of cattle trampling, we built two mathematical models. First we used a temperature‐driven model of egg‐to‐fry mortality representative of the developmental stages during which embryos would be vulnerable to trampling. Cattle trampling was an additional source of mortality (beyond natural mortality), and we modeled egg‐to‐fry mortality across a range of trampling rates (25–125% per month) for scenarios assuming low (0.60), moderate (0.81), and high (0.95) natural mortality. We then used a matrix model to determine how trampling affected population growth (λ), assuming initially stable (λ = 1.008) or slow‐growing populations (λ = 1.025 and 1.05). Cattle trampling concentrated over a few days when the embryos were most sensitive caused greater egg‐to‐fry mortality than when the same amount of trampling occurred over one month. Trampling caused a large increase in egg‐to‐fry mortality when that natural mortality was low, but the overall population‐level effect was far less than might have been anticipated from the rate of trampling itself. Nonetheless, small reductions in population growth rate could be biologically significant for populations with little or no demographic resilience, and trampling rates as low as 25% could lead to negative population growth. The rapid reduction in resilience with increased trampling rates (>50%) means that even growing populations are less likely to recover from periodic fluctuations. The overall risk posed by trampling will depend on whether cutthroat trout populations face concurrent threats that have already reduced their abundance and resilience. Biologists can potentially use the egg‐to‐fry model and thermograph data to identify dates when limiting cattle presence in or near stream habitats would likely reduce mortality from trampling. Evaluation of grazing policies on federal lands may be needed to ensure that species conservation and land use concerns are equitably balanced.
A Population-Based Study of Sexual Orientation Identity and Gender Differences in Adult Health
Authors: Conron Kerith J. , Mimiaga Matthew J. , Landers Stewart J.
Published: June 2010

Objectives. We provide estimates of several leading US adult health indicators by sexual orientation identity and gender to fill gaps in the current literature.

Methods. We aggregated data from the 2001–2008 Massachusetts Behavioral Risk Factor Surveillance surveys (N = 67 359) to examine patterns in self-reported health by sexual orientation identity and gender, using multivariable logistic regression.

Results. Compared with heterosexuals, sexual minorities (i.e., gays/lesbians, 2% of sample; bisexuals, 1%) were more likely to report activity limitation, tension or worry, smoking, drug use, asthma, lifetime sexual victimization, and HIV testing, but did not differ on 3-year Papanicolaou tests, lifetime mammography, diabetes, or heart disease. Compared with heterosexuals, bisexuals reported more barriers to health care, current sadness, past-year suicidal ideation, and cardiovascular disease risk. Gay men were less likely to be overweight or obese and to obtain prostate-specific antigen tests, and lesbians were more likely to be obese and to report multiple risks for cardiovascular disease. Binge drinking and lifetime physical intimate partner victimization were more common among bisexual women.

Conclusions. Sexual orientation disparities in chronic disease risk, victimization, health care access, mental health, and smoking merit increased attention. More research on heterogeneity in health and health determinants among sexual minorities is needed.
A Design Strength Equation for Collapse of Expanded OCTG
Authors: Klever Frans J.
Published: June 2010

Expandable tubulars provide exciting new opportunities for well design and construction. This technology has permitted access to hydrocarbons that could not be reached by conventional drilling techniques. Design tools similar to those available for conventional oil-country tubular goods (OCTG) are required to facilitate further dissemination and application of expandable tubulars. In particular, equations for performance properties of expanded pipe are needed.

This paper describes a method for developing an equation for the design collapse strength of any particular expandable-pipe product. It is based on the combination of collapse-test data and theoretical modeling, and its statistical approach is fully consistent with that used for conventional OCTG described in ISO/TR 10400:2007 (2007) or API TR 5C3 (2008).

On the basis of an example set of expanded L80 pipes, results are presented fitting the collapse data with an anisotropic version of the Klever and Tamano (KT) collapse equation (Klever and Tamano 2006) that has been calibrated recently to conventional OCTG. By adapting three parameters, the anisotropic KT model can also model the collapse strength of the expanded-pipe data over a range of pipe diameters, wall thicknesses, and expansion ratios. The historical API BULL 5C3 (1994) collapse formulas, even with adapted plastic-collapse parameters and reduced yield strength (YS), were found not suitable for matching this set of expanded-pipe collapse data.

Manufacturers may use the procedure described in this paper to develop design strength equations for specific expandable-pipe products, leading to product-specific sets of best-fit KT model parameters. The new equation takes account of the theoretical effect of internal pressure and axial load on collapse. The API SC5 RG ET Resource Group on expandable tubulars is incorporating the approach presented in this paper into the draft API RP 5-EX Recommended Practice.
Stimulating Unconventional Reservoirs: Maximizing Network Growth While Optimizing Fracture Conductivity
Authors: Warpinski N.R. , Mayerhofer M.J. , Vincent M.C. , Cipolla C.L. , Lolon E.P.
Published: June 2010

Unconventional reservoirs such as gas shales and tight gas sands require technology-based solutions for optimum development. The successful exploitation of these reservoirs has relied on some combination of horizontal drilling, multi-stage completions, innovative fracturing and fracture mapping to engineer economic completions. However, the requirements for economic production all hinge on the matrix permeability of these reservoirs, supplemented by the conductivity that can be generated in hydraulic fractures and network fracture systems. Simulations demonstrate that ultra-low shale permeabilities require an interconnected fracture network of moderate conductivity with a relatively small spacing between fractures to obtain reasonable recovery factors. Microseismic mapping demonstrates that such networks are achievable and the subsequent production from these reservoirs supports both the modelling and the mapping. Tight gas sands, having orders of magnitude greater permeability than the gas shales, may be successfully depleted without inducing complex fracture networks, but other issues of damage and zonal coverage complicate recovery in these reservoirs. As with the shales, mapping has proved itself to be valuable in assessing the fracturing results.

Introduction

Unconventional reservoirs provide a significant fraction of gas production in North America and increasing amounts in some other regions of the world. Such reservoirs include tight gas sands, coalbed methane (CBM), and gas shales; in 2006 these reservoirs provided 43% of the US production of natural gas [Kuuskraa(1)]. Because of their limited permeability, which is foremost among many other complexities, some type of stimulation process (and/or dewatering in the case of CBM) is required to engender economic recovery from wells drilled into these formations. The focus of this paper is on gas shales, with particular emphasis on how these reservoirs perform relative to tight gas sands. The important role of natural fractures in both the stimulation and production processes, the importance of conductivity in the developed fracture or fracture system, and the critical influence of the matrix permeability are investigated using both mapping and modeling results.
Multilaterals Drilling and Sustainable Openhole Production from Theory to Field-Case Studies
Authors: Hoang Son K. , Abousleiman Younane N. , Al-Tahini Ashraf
Published: June 2010

Drilling and production optimization are two closely related operations for successful well construction and reservoir management, in particular for multilaterals. Unfortunately, to date, analytical study for the stability of multilaterals has been very limited because of the complex geometry and stress state involved. This work entails a recently derived analytical solution to estimate the safe mudweight window for wellbore stability during drilling and to predict the maximum pressure depletion for a stable junction during production. The presented solution is capable of handling the complexity of the 3D anisotropic state of stress as well as any main-bore and lateral size, inclination, and azimuth. The study shows that the design of multilateral junctions, especially inclination and azimuth of both wellbores with respect to regional in-situ stresses, plays a crucial role in the multilateral-junction stability and the critical pressure depletion to prevent solids production and wellbore collapse. A field case study of an openhole multilateral well drilled in the Khuff-C formation, Ghawar field, Saudi Arabia, is analyzed here with drilling data, core-retrieved rock properties, and pressure-depletion and production estimates. The results showed alternative optimized completions that could have been applied early in the drilling and branching of the laterals. Practical guidelines concerning branching optimization have been established for junction planning and execution. The new analytical modeling has also been calibrated with a published peer-reviewed large-scale experimental program simulating both the anisotropy of far-field stresses and the complex junction geometry with exceptional qualitative and quantitative results.
Multiphase Well-Rate Measurements Applied to Reservoir Analysis
Authors: Tosic S.. , Mehdizadeh P..
Published: June 2010

New technology of multiphase measurement has been widely adopted by the oil industry. The meters that use this technology are either permanently installed or periodically used for well testing during, for example, flowback, well appraisal, and trials. Consistent, reliable, and accurate flow measurement plays an important role in reservoir and production engineering. However, industry trends show that many practitioners do not fully use the potential of continuous online measurements for reservoir- and production-engineering assessments. This paper will show how online-multiphase-measurement data can be applied to reservoir and production analyses and how additional useful results can be obtained. Field examples from the Gulf of Mexico (GOM) will be presented to support the process.

To start, the paper reviews the role of pressure-transient analysis (PTA) and flux rate for assessing the health of the reservoir. PTA gives useful information about the health of the well (skin) and the reservoir properties. It is an established analysis methodology that requires two important inputs—bottomhole pressure and flow rate. If the flow rates are not accurate, the results from PTA would be erroneous, and calculation of downhole-flow velocity would be incorrect. These uncertainties could result in wells producing below or above optimal levels. Either case would lead to production loss or well damage and the need for remedial workover. Unfortunately, the maximum safe-rate term is not easy to predict. With high-producing wells, minor measurement error can result in significant inaccuracies in related calculations for reservoir or well parameters. For instance, if the well-flow velocity in the formation exceeds the critical velocity for fines movement, formation fines would start moving. Once they start moving, additional near-wellbore-region damage would be created or the screen may get eroded.

Production-data analysis (PDA) such as rate-normalized-pres- sure (RNP) analysis in conjunction with continuous flow-rate measurements, provided by an online multiphase flowmeter (MPFM), can be used to obtain additional reservoir parameters. In applications discussed in this paper, flow rates from the multiphase meters were used extensively for reservoir and well surveillance, flow assurance, and the well-production allocation.
Adaptively Localized Continuation-Newton Method—Nonlinear Solvers That Converge All the Time
Authors: Younis R.M.. M. , Tchelepi H.A.. A. , Aziz K..
Published: June 2010

Growing interest in understanding, predicting, and controlling advanced oil-recovery methods emphasizes the importance of numerical methods that exploit the nature of the underlying physics. The fully implicit method offers unconditional stability of the discrete approximations. This stability comes at the expense of transferring the inherent physical stiffness onto the coupled nonlinear residual equations that are solved at each timestep. Current reservoir simulators apply safeguarded variants of Newton's method that can neither guarantee convergence nor provide estimates of the relation between convergence rate and timestep size. In practice, timestep chops become necessary and are guided heuristically. With growing complexity, such as in thermally reactive compositional flows, convergence difficulties can lead to substantial losses in computational effort and prohibitively small timesteps. We establish an alternative class of nonlinear iteration that converges and associates a timestep to each iteration. Moreover, the linear solution process within each iteration is performed locally.

By casting the nonlinear residual equations for a given timestep as an initial-value problem, we formulate a continuation-based solution process that associates a timestep size with each iteration. Subsequently, no iterations are wasted and a solution is always attainable. Moreover, we show that the rate of progression is as rapid as that for a convergent standard Newton method. Moreover, by exploiting the local nature of nonlinear wave propagation typical to multiphase-flow problems, we establish a linear solution process that performs computation only where necessary. That is, given a linear convergence tolerance, we identify a minimal subset of solution components that will change by more than the specified tolerance. Using this a priori criterion, each linear step solves a reduced system of equations. Several challenging examples are presented, and the results demonstrate the robustness and computational efficiency of the proposed method.
Probabilistic Well-Time Estimation Revisited
Authors: Adams A.J.. J. , Gibson C.. , Smith R..
Published: June 2010

Probabilistic estimation of well duration has been common practice for more than a decade; many papers have been written on the subject, and commercial software is available for the purpose. Is the subject, therefore, mature? The authors suggest that this is not the case and show that several essential aspects of both data characterization and probabilistic analysis have been overlooked in previous contributions.

In 2007, Nexen began a study with the objective of improving our process for well-time estimation. Its workscope was to Assemble a statistically significant historical well database.Develop a consistent definition of nonproductive time (NPT) as it relates to the original approved-for-expenditure (AFE) timings.Reanalyze the historical well database for NPT from the original daily drilling reports (DDRs), on the basis of the definition above.Decide how NPT is best characterized (that is, determine the correct choice of input variables).Determine the associated occurrence frequencies and probability-density-function (PDF) parameters from the historical database.Validate the probabilistic model, by comparison of program predictions against the historical data set.Work with a software provider to implement any necessary changes in a commercially available product.

A database of 118 central North Sea wells was reanalyzed independently for NPT from the original DDRs. These considerably underestimated the true NPT, by 19.7% on average. Train wrecks (mechanical NPT events of more than 2.5 days) were only 4% by number but contributed 50% of NPT by duration. It was found that "ordinary" mechanical NPT, train wrecks, waiting on weather (WOW) in open water, and WOW with riser connected are all statistically distinct, with very different occurrence frequencies and PDFs. Earlier workers did not observe this distinction or properly validate their models against the well database.

Therefore, it is impossible to obtain historically accurate probabilistic well-time predictions (i.e., that are consistent with the historical database) using the previous state of the art. Moreover, such predictions will generally be underestimates. This paper describes an accurate method that overcomes previous limitations. While central North Sea data are used, the analysis techniques are not area specific, and the method may be applied easily to other areas in the oil field.
Quantifying Transient Effects in Altered-Stress Refracturing of Vertical Wells
Authors: Roussel Nicolas P. , Sharma Mukul M.
Published: June 2010

The production or injection of fluids in reservoirs results in a redistribution of stresses. In this paper, the extent of stress reorientation has been calculated for fractured production and injection wells and the results have been analyzed for their effect on refracturing operations. Rules of thumb and charts have been provided to help with candidate-well selection for refracturing on the basis of the study.

For previously fractured wells, it is possible to create a secondary fracture that is perpendicular to the first. The secondary orthogonal fracture can be created only within a certain time window that, in turn, depends on the reservoir properties. Conditions leading to orthogonal secondary fractures in different kinds of reservoirs (oil, gas, and tight gas reservoirs) have been analyzed to establish some rules of thumb. The effects of the layers bounding the pay zone and of permeability heterogeneity and anisotropy on stress reorientation are also discussed.

Our results allow us to quantify the phenomenon of orthogonal secondary fracturing around fractured production wells by calculating the extent of the stress-reversal region as a function of time. The results of our model are shown to agree qualitatively with field observations obtained from microseismic measurements. The model presented in the study helps to clarify the concept of refracturing and provides a quantitative estimate of the time window for refracturing as a function of dimensionless parameters. The final result demonstrates the potential of the model to increase the reservoir sweep in unconventional reservoirs for which the optimum time window for refracturing is on the order of months to years. The conclusions of this study are useful for the design of refracturing operations and for candidate-well selection.