bluuebunny/crossref_metadata_2025 huggingface dataset:
Harmonic Maps, Loop Groups, and Integrable Systems
Authors: Guest Martin A.
Published: June 2012

Harmonic maps are generalisations of the concept of geodesics. They encompass many fundamental examples in differential geometry and have recently become of widespread use in many areas of mathematics and mathematical physics. This is an accessible introduction to some of the fundamental connections between differential geometry, Lie groups, and integrable Hamiltonian systems. The specific goal of the book is to show how the theory of loop groups can be used to study harmonic maps. By concentrating on the main ideas and examples, the author leads up to topics of current research. The book is suitable for students who are beginning to study manifolds and Lie groups, and should be of interest both to mathematicians and to theoretical physicists.
Social Dominance
Authors: Sidanius Jim , Pratto Felicia
Published: June 2012

This volume focuses on two questions: why do people from one social group oppress and discriminate against people from other groups? and why is this oppression so mind numbingly difficult to eliminate? The answers to these questions are framed using the conceptual framework of social dominance theory. Social dominance theory argues that the major forms of intergroup conflict, such as racism, classism and patriarchy, are all basically derived from the basic human predisposition to form and maintain hierarchical and group-based systems of social organization. In essence, social dominance theory presumes that, beneath major and sometimes profound difference between different human societies, there is also a basic grammar of social power shared by all societies in common. We use social dominance theory in an attempt to identify the elements of this grammar and to understand how these elements interact and reinforce each other to produce and maintain group-based social hierarchy.
Modeling in Materials Processing
Authors: Dantzig Jonathan A. , Tucker Charles L.
Published: June 2012

Mathematical modeling and computer simulation are useful tools for improving materials processing. While courses in materials processing have covered modeling, they have traditionally been devoted to one particular class of materials, that is, polymers, metals, or ceramics. This text offers a different approach, presenting an integrated treatment of metallic and non-metallic materials. The authors show that a common base of knowledge - specifically, the fundamentals of heat transfer and fluid mechanics - provides a unifying theme for these seemingly disparate areas. Emphasis is placed on understanding basic physical phenomena and knowing how to include them in a model. The book also treats selected numerical methods, showing the relationship between the physical system, analytical solution, and the numerical scheme. A wealth of practical, realistic examples are provided, as well as homework exercises. Students, and practising engineers who must deal with a wide variety of materials and processing problems, will benefit from the unified treatment presented in this book.
Theory of Orbit Determination
Authors: Milani Andrea , Gronchi Giovanni
Published: June 2012

Determining orbits for natural and artificial celestial bodies is an essential step in the exploration and understanding of the Solar System. However, recent progress in the quality and quantity of data from astronomical observations and spacecraft tracking has generated orbit determination problems which cannot be handled by classical algorithms. This book presents new algorithms capable of handling the millions of bodies which could be observed by next generation surveys, and which can fully exploit tracking data with state-of-the-art levels of accuracy. After a general mathematical background and summary of classical algorithms, the new algorithms are introduced using the latest mathematical tools and results, to which the authors have personally contributed. Case studies based on actual astronomical surveys and space missions are provided, with applications of these new methods. Intended for graduate students and researchers in applied mathematics, physics, astronomy and aerospace engineering, this book is also of interest to non-professional astronomers.
Cookery for the Hospitality Industry
Authors: Dodgshun Graham , Peters Michel , O'Dea David
Published: June 2012

A must-have book for thirty years, and now in its sixth edition, Cookery for the Hospitality Industry remains Australia's most trusted and reliable reference for commercial cookery students, apprentice chefs and those studying vocational courses in schools. It covers the essential skills, methods and principles of cookery as well as the core competencies listed within the Australian National Training Package for Commercial Cookery. This book provides trade apprentices and commercial cookery students with everything they need to know to achieve trade status and more. It is the only textbook that genuinely addresses the needs of Australian students by covering Australian qualifications and reflecting Australian conditions, ingredients and our unique cuisine.
Ensuring Accountability and Transparency through Integrated Public Management Systems
Authors: Apaza Carmen R.
Published: June 2012

Government efforts to prevent corruption vary from reformulating laws and regulations to establishing control and oversight mechanisms such as integrated public management systems within central and local governments. However, several technical issues as well as social-political events may critically affect its effectiveness. This article addresses this issue by analyzing the Integrated Management System and Administrative Modernization (SIGMA for its acronym in Spanish) established in Bolivia through a World Bank US$15 million loan. Possible solutions and next steps to improve its effectiveness that can be applied to other countries are suggested.
Motivated Reasoning, Political Sophistication, and Associations between President Obama and Islam
Authors: Hartman Todd K. , Newmark Adam J.
Published: June 2012

Recent polls reveal that between 20% and 25% of Americans erroneously indicate that President Obama is a Muslim. In this article, we compare individuals' explicit responses on a survey about religion and politics with reaction time data from an Implicit Association Test (IAT) to investigate whether individuals truly associate Obama with Islam or are motivated reasoners who simply express negativity about the president when given the opportunity. Our results suggest that predispositions such as ideology, partisanship, and race affect how citizens feel about Obama, which in turn motivates them to accept misinformation about the president. We also find that these implicit associations increase the probability of stating that Obama is likely a Muslim. Interestingly, political sophistication does not appear to inoculate citizens from exposure to misinformation, as they exhibit the same IAT effect as less knowledgeable individuals.
“We're Off to Replace the Wizard”: Lessons from a Collaborative Group Project Assignment
Authors: Centellas Miguel , Love Gregory J.
Published: June 2012

This article examines the effectiveness of a collaborative group learning project for teaching a core competency in comparative politics: constitutional structures. We use a quasi-experimental design and propensity score matching to assess the value of a constitutional writing group project and presentation. The results provide strong evidence that these learning tools are highly valuable for teaching abstract concepts. Students who participated in the project scored significantly higher on a short series of questions in final exams given several weeks after the completion of the group project. Somewhat paradoxically, the project increased competency but did not affect student self-reported interest in the subject matter. The challenges and improvements that can be made for the use these types of learning tools concludes the article.
Teaching Diversity: Using a Multifaceted Approach to Engage Students
Authors: Auerbach Arthur H.
Published: June 2012

The traditional format for teaching courses to undergraduate students has long been that of lecture when professors speak and students listen. However, as times have evolved so too have the pedagogical methods in the classroom. In teaching a course on diversity and discrimination in the society, this instructor opted to combine several teaching methods as a means of not only conveying the substantive material to the class but, more importantly, engaging the students at an interactive learning level. By combining traditional lecture with watching/discussing documentaries and incorporating structured student debate, a dynamic learning environment was created. As a result of incorporating the students into every aspect of the class, the students learned from both the instructor and students alike. Thus, the use of this multifaceted approach created a positive and engaging learning environment for the whole class.
The Negative Consequences of Uncivil Political Discourse
Authors: Maisel L. Sandy
Published: June 2012

Congressman Alan West (R-FL) passed the incivility duck test when he described his fellow Floridian Congresswoman Debbie Wasserman Schultz (D) as “the most vile, unprofessional and despicable member of the House of Representatives.” That read like incivility, sounded like incivility, and was universally interpreted to be uncivil, thus it probably was.
Providing Science to Improve the Public's Health: A Fellow's View from the Office of the US Surgeon General
Authors: Alley Dawn
Published: June 2012

As America's doctor, The US Surgeon General provides Americans with the best scientific information available on how to improve their health and reduce the risk of illness and injury. As a scientist interested in translating evidence to improve the public's health, spending a year as a fellow in the Office of the US Surgeon General has been the opportunity of a lifetime.
Split from slip and schist: Crustal anisotropy beneath northern Cascadia from non‐volcanic tremor
Authors: Bostock M. G. , Christensen N. I.
Published: June 2012

Polarization and splitting analyses of minute‐long windows of non‐volcanic tremor at 3‐component stations in the vicinity of southern Vancouver Island provide new evidence for the presence of anisotropy within the crustal portion of the North American plate beneath Cascadia. As reported previously, tremor particle motions are predominantly horizontal and inferred to manifest an upgoing wavefield composed primarily of S‐waves. Under this assumption, estimates of incidence angle and back azimuth can be deduced from orientation of the smallest principle direction of motion. When subjected to standard S‐wave splitting analysis, most stations yield systematic and reproducible fast polarization directions. Estimates of original polarization direction are more scattered and splitting times often exhibit multimodal distributions. Numerical simulations, wherein band‐limited synthetic seismograms comprising contributions from multiple sources are analyzed for splitting, neatly reproduce these characteristics and thereby provide a framework for interpretation. A number of stations in our study sit astride the San Juan fault which, based on reflection studies, dips approximately 60 to 70° to the north. Underlying these stations is the Leech River Complex consisting of strongly foliated greenschist facies phyllites with steeply dipping foliations striking parallel to fast polarization directions of split S‐waves. Detailed laboratory velocity measurements at elevated pressures show that as little as 2 to 3 km of vertically dipping Leech River phyllite are required to produce the observed splitting. These phyllites have some of the highest S‐wave anisotropies measured to date and are part of a once continuous belt of anisotropic crust extending over 2000 km along the western North American coast from southern Vancouver Island to southwest Alaska.
Aromatic hydrocarbons as ozone precursors before and after outbreak of the 2008 financial crisis in the Pearl River Delta region, south China
Authors: Zhang Yanli , Wang Xinming , Blake Donald R. , Li Longfeng , Zhang Zhou , Wang Shaoyi , Guo Hai , Lee Frank S. C. , Gao Bo , Chan Loyin , Wu Dui , Rowland F. Sherwood
Published: June 2012

In the second half of 2008 China's highly industrialized Pearl River Delta (PRD) region was hard‐hit by the financial crisis (FC). This study reports volatile organic compounds measured in the PRD during November–December in both 2007 before the FC and 2008 after the FC. While total mixing ratios of non‐methane hydrocarbons (NMHCs) on average were only about 7% lower from 40.2 ppbv in 2007 to 37.5 ppbv in 2008, their ozone formation potentials (OFPs) dropped about 30%, resulting from about 55% plummet of aromatic hydrocarbons (AHs) against a greater than 20% increase of total alkanes/alkenes. The elevated alkanes and alkenes in 2008 could be explained by greater emissions from vehicle exhausts and LPG combustion due to rapid increase of vehicle numbers and LPG consumption; the drop of AHs could be explained by reduced emissions from industries using AH‐containing solvents due to the influence of the FC, as indicated by much lower ratios of toluene to benzene and of xylenes/trichloroethylene/tetrachloroethylene to carbon monoxide (CO) in 2008. Source apportionment by positive matrix factorization (PMF) also revealed much less contribution of industry solvents to total anthropogenic NMHCs and particularly to toluene and xylenes in 2008 than in 2007. Based on PMF reconstructed source contributions, calculated OFPs by industrial emissions were responsible for 40.8% in 2007 in contrast to 18.4% in 2008. Further investigation into local industry output statistics suggested that the plummet of AHs in 2008 should be attributed to small enterprises, which contributed largely to ambient AHs due to their huge numbers and non‐existent emission treatment, but were much more influenced by the FC.
Experimental meandering river with chute cutoffs
Authors: van Dijk W. M. , van de Lageweg W. I. , Kleinhans M. G.
Published: June 2012

Braided rivers are relatively simple to produce in the laboratory, whereas dynamic meandering rivers have not been sustained beyond initial bend formation. Meandering is theoretically explained by bend instability growing from planimetric perturbation, which convects downstream. In this study, we experimentally tested the importance of upstream perturbation and chute cutoff development in the evolution and dynamics of a meandering channel pattern. The initial straight channel had a transversely moving upstream inlet point and silt‐sized silica flour was added to the sediment feed to allow floodplain formation. We obtained a dynamic meandering river with scroll bars. Bend growth was alternated by chute cutoffs that formed across the point bars. Meandering was maintained as one channel was disconnected by a plug bar. The curvature at the chute bifurcation transported sediment and build a new floodplain, while the other channel widens. At the end of the experiment, the fluvial plain exhibited a meandering channel, point bars, chutes and abandoned and partially filled channels with a slightly cohesive floodplain surface similar to natural meandering gravel bed rivers. We conclude that the necessary and sufficient conditions for dynamic meandering gravel bed river are a sustained dynamic upstream perturbation and floodplain formation.
Sea surface temperature variability in southern Okinawa Trough during last 2700 years
Authors: Wu Weichao , Tan Wenbing , Zhou Liping , Yang Huan , Xu Yunping
Published: June 2012

Most of the temperature reconstructions for the past two millennia are based on proxy data from various sites on land. Here we present a bidecadal resolution record of sea surface temperature (SST) in Southern Okinawa Trough for the past ca. 2700 years by analyzing tetraether lipids of planktonic archaea in the ODP Hole 1202B, a site under the strong influence of Kuroshio Current and East Asian monsoon. The reconstructed SST anomalies generally coincided with previously reported late Holocene climate events, including the Roman Warm Period, Sui‐Tang dynasty Warm Period, Medieval Warm Period, Current Warm Period, Dark Age Cold Period and Little Ice Age. However, the Medieval Warm Period usually thought to be a historical analogue for the Current Warm Period has a mean SST of 0.6–0.8°C lower than that of the Roman Warm Period and Sui‐Tang dynasty Warm Period. Despite an increase since 1850 AD, the mean SST in the 20th century is still within the range of natural variability during the past 2700 years. A close correlation of SST in Southern Okinawa Trough with air temperature in East China, intensity of East Asian monsoon and the El‐Niño Southern Oscillation index has been attributed to the fluctuations in solar output and oceanic‐atmospheric circulation.
The exchange of Intermediate Water in the southeast Atlantic: Water mass transformations diagnosed from the Lagrangian analysis of a regional ocean model
Authors: Rimaud Julie , Speich Sabrina , Blanke Bruno , Grima Nicolas
Published: June 2012

Results from a regional ocean model and numerical Lagrangian analyses are compared with in situ measurements to describe the properties and dynamics of Antarctic Intermediate Water (AAIW) in the region of the Cape Basin. The AAIW that originates in the South Atlantic (A‐AAIW) at 8°W follows two branches. A southern branch, flowing mostly south of 40°S, is blocked by topography and is deflected westward without significant changes in its physical properties. A northern branch crosses the Cape Basin with strong modification of its physical properties. The AAIW that originates in the Indian Ocean (I‐AAIW) flows into the Atlantic Ocean via the Agulhas Current and undergoes small physical changes in the Cape Basin. In the model, the salinity ranges of A‐AAIW and I‐AAIW cores that reach the southeast Atlantic are 34.2–34.5 and 34.5–34.6, respectively. The modeled AAIW distribution and behavior compare well with observations, despite a bias of +0.2 in salinity. To investigate the dynamical processes involved in the interocean exchanges of these AAIW varieties, we use diagnoses based on the Okubo‐Weiss parameter and the directional variations of trajectories of particles transported by the model velocity field. Our results suggest that I‐AAIW flows into the Cape Basin more within eddies, and particularly within cyclones, than A‐AAIW. Once the mixing of both varieties operates, physical and behavioral differences fade and the resulting AAIW flows over the Walvis Ridge in a less turbulent way as part of the Benguela Current, with salinity between 34.55 and 34.6.
Project Nemmadi: The Bytes and Bites of ICT Adoption and Implementation in India
Authors: Das Aundhe Madhuchhanda , Narasimhan Ramesh
Published: June 2012

This case documents the challenges involved in the adoption of information and communication technology (ICT) by the government in a democratic system, especially in the context of a developing country. Nemmadi was an e-governance project initiated in 2004 by the government of the state of Karnataka located in the southern part of India. Since the beginning of the new millennium, the policy and the political environment in Karnataka had turned quite favourable for such ICT initiatives. Aimed at improving the transparency, accountability and efficiency of the government administration at the village level, Nemmadi was an ambitious project conceived to offer digital services to rural citizens across 800 hoblis (cluster of villages) in the state. The services included issue of certificates of several kinds, which entitled the citizens belonging to economically and socially backward sections of the society to avail of benefits and concessions under various government schemes conceived as part of affirmative action by the state. Project Nemmadi was conceived as a ‘sequel’ to a celebrated e-governance initiative called Bhoomi, which involved digitization of seven million agricultural land records, and was a landmark in e-governance in India. Bhoomi was championed and closely led by Shekhar Puri, the then Principal Secretary of e-governance who also led the Nemmadi project during its roll-out phase. The roll-out of Project Nemmadi faced many challenges. The village functionaries and their interface with Nemmadi impacted project implementation, and hence adoption. It had received its share of bouquets and brickbats and had won several awards. Naveen Iyer took charge as the Principal Secretary of this department. Naveen's recommendations to the political leadership and the decisions that follow could transform the project to a truly village-level Citizen Service Center, thus paving the way for an e-governance revolution directly touching the lives of the people in the villages, where 70% of India lives. This could restore Karnataka to its original position on e-governance leadership and serve as a key accomplishment for Naveen in his new role.
A theoretical and simulation study of the self-assembly of a binary blend of diblock copolymers
Authors: Padmanabhan Poornima , Martinez-Veracoechea Francisco J. , Araque Juan C. , Escobedo Fernando A.
Published: June 2012

Pure diblock copolymer melts exhibit a narrow range of conditions at which bicontinuous and cocontinuous phases are stable; such conditions and the morphology of such phases can be tuned by the use of additives. In this work, we have studied a bidisperse system of diblock copolymers using theory and simulation. In particular, we elucidated how a short, lamellar-forming diblock copolymer modifies the phase behavior of a longer, cylinder-forming diblock copolymer. In a narrow range of intermediate compositions, self-consistent field theory predicts the formation of a gyroid phase although particle-based simulations show that three phases compete: the gyroid phase, a disordered cocontinuous phase, and the cylinder phase, all having free energies within error bars of each other. Former experimental studies of a similar system have yielded an unidentified, partially irregular bicontinuous phase, and our simulations suggest that at such conditions the formation of a partially transformed network phase is indeed plausible. Close examination of the spatial distribution of chains reveals that packing frustration (manifested by chain stretching and low density spots) occurs in the majority-block domains of the three competing phases simulated. In all cases, a double interface around the minority-block domains is also detected with the outer one formed by the short chains, and the inner one formed by the longer chains.
Ultrasonic evaluation of early damage of a coating by using second-harmonic generation technique
Authors: Shui Guoshuang , Wang Yue-Sheng
Published: June 2012

For an in-service structure with a coating, damage accumulation may develop gradually within the coating or at the interface between the substrate and coating under external loads. By considering the fact that different levels of external load are closely related to the degrees of accumulated early damage which is very difficult to be measured directly, and that the early damage may cause the nonlinearity of Rayleigh surface waves, the acoustic nonlinearity parameter (ANP) is employed as an indicator of early damage of a coating. This research reports on the experimental observation of the monotonic correlation between the ANP measured with nonlinear Rayleigh waves and the applied stress on an AZ31 magnesium alloy plate specimen using ultrasonic second-harmonic generation technique. Rayleigh waves are generated and detected with wedge transducers, and the nonlinearity parameters are measured at different stress levels for the specimens with coatings. The result shows that there is a significant increase in the nonlinearity parameters with the increasing tensile stress although there is no obvious change for the coating when the tensile stress is less than a certain level. The research suggests an effective nondestructive evaluation method to track the coating damage using the higher order harmonic generation technique.
Electron transport in discontinuous gold films and the effect of Coulomb blockade and percolation
Authors: Müller K.-H. , Yajadda M. M. A.
Published: June 2012

Understanding the electron transport in disordered assemblies of weakly coupled nano-sized metal clusters is important for many applications. Here, we investigate experimentally and theoretically the electron transport properties of metal cluster assemblies in the form of discontinuous gold films. Discontinuous films of different average island size are produced by sputter deposition, and the resistance and the non-linear current-voltage (I-V) characteristics of the films are measured as a function of temperature. To interpret the experimental electron transport data, a conduction percolation model is employed where broad probability distributions for both the tunnel junction gaps and the Coulomb blockade energies are used. Excellent agreement between experimental data and model calculations is found. In particular, the non-Arrhenius resistive behavior, the I-V power-law behavior, and the I-V characteristics at large bias voltage are all shown to be due to a conduction percolation mechanism governing disordered networks of nano-sized metal islands connected by tunnel junctions.
Shear instability in magnetized, collisional dusty plasmas
Authors: Pandey B. P. , Vladimirov S. V. , Samarian A. A.
Published: June 2012

The shear instability of magnetized, collisional dusty plasma is investigated in the present work. It is demonstrated that the relative drift between the charged dust and magnetised electrons and ions which give rise to the Hall effect is crucial to this instability. Although the nature of present shear instability is similar to the Kelvin-Helmholtz instability, the role of magnetic field in the present case is important in destabilising waves. The maximum growth rate of the instability is proportional only to the shear gradient and is independent of the ambient magnetic field strength. Most unstable wavenumber is a function of ambient dust parameters.
Conduction mechanisms in p-type Pb1−xEuxTe alloys in the insulator regime
Authors: Peres M. L. , Rubinger R. M. , Ribeiro L. H. , L. Rubinger C. P. , Ribeiro G. M. , Chitta V. A. , Rappl P. H. O. , Abramof E.
Published: June 2012

Electrical resistivity measurements were performed on p-type Pb1−xEuxTe films with Eu content x = 4%, 5%, 6%, 8%, and 9%. The well-known metal-insulator transition that occurs around 5% at room temperature due to the introduction of Eu is observed, and we used the differential activation energy method to study the conduction mechanisms present in these samples. In the insulator regime (x > 6%), we found that band conduction is the dominating conduction mechanism for high temperatures with carriers excitation between the valence band and the 4f levels originated from the Eu atoms. We also verified that mix conduction dominates the low temperatures region. Samples with x = 4% and 5% present a temperature dependent metal insulator transition and we found that this dependence can be related to the relation between the thermal energy kBT and the activation energy Δɛa. The physical description obtained through the activation energy analysis gives a new insight about the conduction mechanisms in insulating p-type Pb1−xEuxTe films and also shed some light over the influence of the 4f levels on the transport process in the insulator region.
Fabrication of long poly(dimethyl siloxane) nanochannels by replicating protein deposit from confined solution evaporation
Authors: Lo Kuo-Feng , Juang Yi-Je
Published: June 2012

A relatively simple, inexpensive and reliable technique was developed to fabricate an array of nanochannels. Moreover, the nanochannels are directly integrated to microchannels as a whole, which facilitates solution loading from the millimeter-scaled loading reservoirs into the nanochannels. It is found that continuous bovine serum albumin (BSA) line structures with triangle-like cross section at nanoscale can be obtained by evaporation of BSA solution with concentration between 0.5 wt. % and 1 wt. % inside the microchannels. The poly(dimethyl siloxane) nanochannels were replicated from these line structures, followed by sealing with the glass slide. The DNA molecules can be stretched inside the nanochannels as fabricated.
Krüppel-like factor 9 is a circadian transcription factor in human epidermis that controls proliferation of keratinocytes
Authors: Spörl Florian , Korge Sandra , Jürchott Karsten , Wunderskirchner Minetta , Schellenberg Katja , Heins Sven , Specht Aljona , Stoll Claudia , Klemz Roman , Maier Bert , Wenck Horst , Schrader Annika , Kunz Dieter , Blatt Thomas , Kramer Achim
Published: June 2012

Circadian clocks govern a wide range of cellular and physiological functions in various organisms. Recent evidence suggests distinct functions of local clocks in peripheral mammalian tissues such as immune responses and cell cycle control. However, studying circadian action in peripheral tissues has been limited so far to mouse models, leaving the implication for human systems widely elusive. In particular, circadian rhythms in human skin, which is naturally exposed to strong daytime-dependent changes in the environment, have not been investigated to date on a molecular level. Here, we present a comprehensive analysis of circadian gene expression in human epidermis. Whole-genome microarray analysis of suction-blister epidermis obtained throughout the day revealed a functional circadian clock in epidermal keratinocytes with hundreds of transcripts regulated in a daytime-dependent manner. Among those, we identified a circadian transcription factor, Krüppel-like factor 9 (
Klf9
), that is substantially up-regulated in a cortisol and differentiation-state-dependent manner. Gain- and loss-of-function experiments showed strong antiproliferative effects of
Klf9
. Putative
Klf9
target genes include proliferation/differentiation markers that also show circadian expression in vivo, suggesting that
Klf9
affects keratinocyte proliferation/differentiation by controlling the expression of target genes in a daytime-dependent manner.
Earthquake triggering and large-scale geologic storage of carbon dioxide
Authors: Zoback Mark D. , Gorelick Steven M.
Published: June 2012

Despite its enormous cost, large-scale carbon capture and storage (CCS) is considered a viable strategy for significantly reducing CO
2
emissions associated with coal-based electrical power generation and other industrial sources of CO
2
[Intergovernmental Panel on Climate Change (2005) IPCC Special Report on Carbon Dioxide Capture and Storage. Prepared by Working Group III of the Intergovernmental Panel on Climate Change, eds Metz B, et al. (Cambridge Univ Press, Cambridge, UK); Szulczewski ML, et al. (2012)
Proc Natl Acad Sci USA
109:5185–5189]. We argue here that there is a high probability that earthquakes will be triggered by injection of large volumes of CO
2
into the brittle rocks commonly found in continental interiors. Because even small- to moderate-sized earthquakes threaten the seal integrity of CO
2
repositories, in this context, large-scale CCS is a risky, and likely unsuccessful, strategy for significantly reducing greenhouse gas emissions.
Zinc-finger nuclease-mediated targeted insertion of reporter genes for quantitative imaging of gene expression in sea urchin embryos
Authors: Ochiai Hiroshi , Sakamoto Naoaki , Fujita Kazumasa , Nishikawa Masatoshi , Suzuki Ken-ichi , Matsuura Shinya , Miyamoto Tatsuo , Sakuma Tetsushi , Shibata Tatsuo , Yamamoto Takashi
Published: June 2012

To understand complex biological systems, such as the development of multicellular organisms, it is important to characterize the gene expression dynamics. However, there is currently no universal technique for targeted insertion of reporter genes and quantitative imaging in multicellular model systems. Recently, genome editing using zinc-finger nucleases (ZFNs) has been reported in several models. ZFNs consist of a zinc-finger DNA-binding array with the nuclease domain of the restriction enzyme FokI and facilitate targeted transgene insertion. In this study, we successfully inserted aGFPreporter cassette into theHpEts1gene locus of the sea urchin,Hemicentrotus pulcherrimus. We achieved this insertion by injecting eggs with a pair of ZFNs forHpEts1with a targeting donor construct that contained ∼1-kb homology arms and a2A-histoneH2B–GFPcassette. We increased the efficiency of the ZFN-mediated targeted transgene insertion by in situ linearization of the targeting donor construct and cointroduction of an mRNA for a dominant-negative form ofHpLig4, which encodes theH. pulcherrimushomolog ofDNA ligase IVrequired for error-prone nonhomologous end joining. We measured the fluorescence intensity of GFP at the single-cell level in living embryos during development and found that there was variation in HpEts1 expression among the primary mesenchyme cells. These findings demonstrate the feasibility of ZFN-mediated targeted transgene insertion to enable quantification of the expression levels of endogenous genes during development in living sea urchin embryos.
Early-onset binocularity in preterm infants reveals experience-dependent visual development in humans
Authors: Jandó Gábor , Mikó-Baráth Eszter , Markó Katalin , Hollódy Katalin , Török Béla , Kovacs Ilona
Published: June 2012

Although there is a great deal of knowledge regarding the phylo- and ontogenetic plasticity of the neocortex, the precise nature of environmental impact on the newborn human brain is still one of the most controversial issues of neuroscience. The leading model–system of experience-dependent brain development is binocular vision, also called stereopsis. Here, we show that extra postnatal visual experience in preterm human neonates leads to a change in the developmental timing of binocular vision. The onset age of binocular function, as measured by the visual evoked response to dynamic random dot correlograms (DRDC-VEP), appears to be at around the same time after birth in preterm (4.07 mo) and full-term (3.78 mo) infants. To assess the integrity of the visual pathway in the studied infants, we also measured the latency of the visual-evoked response to pattern reversal stimuli (PR-VEP). PR-VEP latency is not affected by premature birth, demonstrating that the maturation of the visual pathway follows a preprogrammed developmental course. Despite the immaturity of the visual pathway, clearly demonstrated by the PR-VEP latencies, our DRCD-VEP data show that the visual cortex is remarkably ready to accept environmental stimulation right after birth. This early plasticity makes full use of the available extra stimulation time in preterm human infants and results in an early onset of cortical binocularity. According to our data, the developmental processes preceding the onset of binocular function are not preprogrammed, and the mechanisms turning on stereopsis are extremely experience-dependent in humans.
Dynamics of a bacterial multidrug ABC transporter in the inward- and outward-facing conformations
Authors: Mehmood Shahid , Domene Carmen , Forest Eric , Jault Jean-Michel
Published: June 2012

The study of membrane proteins remains a challenging task, and approaches to unravel their dynamics are scarce. Here, we applied hydrogen/deuterium exchange (HDX) coupled to mass spectrometry to probe the motions of a bacterial multidrug ATP-binding cassette (ABC) transporter, BmrA, in the inward-facing (resting state) and outward-facing (ATP-bound) conformations. Trypsin digestion and global or local HDX support the transition between inward- and outward-facing conformations during the catalytic cycle of BmrA. However, in the resting state, peptides from the two intracellular domains, especially ICD2, show a much faster HDX than in the closed state. This shows that these two subdomains are very flexible in this conformation. Additionally, molecular dynamics simulations suggest a large fluctuation of the Cα positions from ICD2 residues in the inward-facing conformation of a related transporter, MsbA. These results highlight the unexpected flexibility of ABC exporters in the resting state and underline the power of HDX coupled to mass spectrometry to explore conformational changes and dynamics of large membrane proteins.
Identifying mechanism-of-action targets for drugs and probes
Authors: Gregori-Puigjané Elisabet , Setola Vincent , Hert Jérôme , Crews Brenda A. , Irwin John J. , Lounkine Eugen , Marnett Lawrence , Roth Bryan L. , Shoichet Brian K.
Published: June 2012

Notwithstanding their key roles in therapy and as biological probes, 7% of approved drugs are purported to have no known primary target, and up to 18% lack a well-defined mechanism of action. Using a chemoinformatics approach, we sought to “de-orphanize” drugs that lack primary targets. Surprisingly, targets could be easily predicted for many: Whereas these targets were not known to us nor to the common databases, most could be confirmed by literature search, leaving only 13 Food and Drug Administration—approved drugs with unknown targets; the number of drugs without molecular targets likely is far fewer than reported. The number of worldwide drugs without reasonable molecular targets similarly dropped, from 352 (25%) to 44 (4%). Nevertheless, there remained at least seven drugs for which reasonable mechanism-of-action targets were unknown but could be predicted, including the antitussives clemastine, cloperastine, and nepinalone; the antiemetic benzquinamide; the muscle relaxant cyclobenzaprine; the analgesic nefopam; and the immunomodulator lobenzarit. For each, predicted targets were confirmed experimentally, with affinities within their physiological concentration ranges. Turning this question on its head, we next asked which drugs were specific enough to act as chemical probes. Over 100 drugs met the standard criteria for probes, and 40 did so by more stringent criteria. A chemical information approach to drug-target association can guide therapeutic development and reveal applications to probe biology, a focus of much current interest.
Thylakoid potassium channel is required for efficient photosynthesis in cyanobacteria
Authors: Checchetto Vanessa , Segalla Anna , Allorent Guillaume , La Rocca Nicoletta , Leanza Luigi , Giacometti Giorgio Mario , Uozumi Nobuyuki , Finazzi Giovanni , Bergantino Elisabetta , Szabò Ildikò
Published: June 2012

A potassium channel (SynK) of the cyanobacterium
Synechocystis
sp. PCC 6803, a photoheterotrophic model organism for the study of photosynthesis, has been recently identified and demonstrated to function as a potassium selective channel when expressed in a heterologous system and to be located predominantly to the thylakoid membrane in cyanobacteria. To study its physiological role, a SynK-less knockout mutant was generated and characterized. Fluorimetric experiments indicated that SynK-less cyanobacteria cannot build up a proton gradient as efficiently as WT organisms, suggesting that SynK might be involved in the regulation of the electric component of the proton motive force. Accordingly, measurements of flash-induced cytochrome

b
6

f turnover and respiration pointed to a reduced generation of ΔpH and to an altered linear electron transport in mutant cells. The lack of the channel did not cause an altered membrane organization, but decreased growth and modified the photosystem II/photosystem I ratio at high light intensities because of enhanced photosensitivity. These data shed light on the function of a prokaryotic potassium channel and reports evidence, by means of a genetic approach, on the requirement of a thylakoid ion channel for optimal photosynthesis.
Pol31 and Pol32 subunits of yeast DNA polymerase δ are also essential subunits of DNA polymerase ζ
Authors: Johnson Robert E. , Prakash Louise , Prakash Satya
Published: June 2012

Replication through a diverse array of DNA lesions occurs by the sequential action of two translesion synthesis (TLS) DNA polymerases (Pols), in which one inserts the nucleotide opposite the lesion and the other carries out the subsequent extension. By extending from the nucleotide inserted by another Pol, Polζ plays an indispensable role in mediating lesion bypass. Polζ comprises the Rev3 catalytic and Rev7 accessory subunits. Pol32, a subunit of the replicative polymerase Polδ, is also required for Polζ-dependent TLS, but how this Polδ subunit contributes to Polζ function in TLS has remained unknown. Here we show that yeast Polζ is a four-subunit enzyme containing Rev3, Rev7, Pol31, and Pol32; in this complex, association with Pol31/Pol32 is mediated via binding of the Rev3 C terminus to Pol31. The functional requirement of this complex is supported by evidence that mutational inactivation of Rev3’s ability to bind Pol31 abrogates Polζ’s role in TLS in yeast cells. These findings identify an unexpected role of Pol31 and Pol32 as two essential subunits of Polζ, and clarify why these proteins are required for Polζ-dependent TLS, but not for TLS mediated by Polη in yeast cells. To distinguish the four-subunit complex from the two-subunit Polζ, we designate the four-subunit enzyme “Polζ-d,” where “-d” denotes the Pol31/Pol32 subunits of Polδ.
Genomic diversity of 2010 Haitian cholera outbreak strains
Authors: Hasan Nur A. , Choi Seon Young , Eppinger Mark , Clark Philip W. , Chen Arlene , Alam Munirul , Haley Bradd J. , Taviani Elisa , Hine Erin , Su Qi , Tallon Luke J. , Prosper Joseph B. , Furth Keziah , Hoq M. M. , Li Huai , Fraser-Liggett Claire M. , Cravioto Alejandro , Huq Anwar , Ravel Jacques , Cebula Thomas A. , Colwell Rita R.
Published: June 2012

The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortality of cholera in Haiti since October 2010, are grim reminders that
Vibrio cholerae
, the etiologic agent of cholera, remains a scourge. We report the isolation of both
V
.
cholerae
O1 and non-O1/O139 early in the Haiti cholera epidemic from samples collected from victims in 18 towns across eight Arrondissements of Haiti. The results showed two distinct populations of
V. cholerae
coexisted in Haiti early in the epidemic. As non-O1/O139
V
.
cholerae
was the sole pathogen isolated from 21% of the clinical specimens, its role in this epidemic, either alone or in concert with
V
.
cholerae
O1, cannot be dismissed. A genomic approach was used to examine similarities and differences among the Haitian
V
.
cholerae
O1 and
V
.
cholerae
non-O1/O139 strains. A total of 47
V
.
cholerae
O1 and 29
V
.
cholerae
non-O1/O139 isolates from patients and the environment were sequenced. Comparative genome analyses of the 76 genomes and eight reference strains of
V
.
cholerae
isolated in concurrent epidemics outside Haiti and 27
V
.
cholerae
genomes available in the public database demonstrated substantial diversity of
V. cholerae
and ongoing flux within its genome.
Objectively assessed physical activity and weight status in Maltese 11–12 year‐olds
Authors: Decelis Andrew , Jago Russell , Fox Kenneth R.
Published: June 2012

The objectives of the study were to identify levels of physical activity and sedentary time and assess how they differ by weight status in Maltese boys and girls. Participants were 234 Maltese children aged 11–12 years, of which 187 (80%) provided complete data. Physical activity was assessed using accelerometry and weight status determined through gender‐specific age‐adjusted Body mass index (BMI). Self‐reported mode of transport to school, TV and computer time, gaming and mobile phone use were assessed by questionnaire. Total physical activity was generally very low and significantly lower for girls than boys at all times on weekdays and on weekends till 7 pm. Overweight and obesity prevalence was 27% and 18.6%, respectively. Differences in overall physical activity were observed between non‐overweight, and overweight and obese boys (p=0.003). Differences in moderate to vigorous intensity physical activity (MVPA) in boys were significant across all weight categories (p=0.001) and in girls (p=0.020) between the overweight (27.6 min), the non‐overweight (26.4 min) and the obese (18.9 min). For weekdays, mean physical activity differences (p=0.013) were observed between non‐overweight (515.5 cpm) and obese boys (416.4 cpm). Differences in MVPA were found (p=0.038) between non‐overweight (4.4 min) and obese boys in the 6 am–3 pm period. Differences were also found between overweight (13.2 min) and obese girls (8.1 min) (p=0.024) in that period. On weekends, mean physical activity differences were found between non‐overweight and overweight boys from 8 am—7 pm but not for girls. Physical activity levels in this sample were very low when compared to recommended levels, while the prevalence of overweight and obesity and sedentary time were high. Girls are significantly less active than boys throughout the week. Activity level differences and patterning across the day and week were related to weight status with obese children showing markedly less activity. These results suggest that we need to provide more opportunities for overweight and obese children to be active throughout the week, with a particular emphasis on physical activity during school hours.
Gender differences in hip and ankle joint kinematics on knee abduction during running
Authors: Sakaguchi Masanori , Ogawa Haruna , Shimizu Norifumi , Kanehisa Hiroaki , Yanai Toshimasa , Kawakami Yasuo
Published: June 2012

The knee is the most common site of running injuries, particularly prevalent in females. The purpose of this study was to clarify gender differences in the lower extremity kinematics during running, with a specific emphasis on the relationships between the distal and proximal factors and the knee joint kinematics. Eleven female and 11 male runners participated in this study. Three‐dimensional marker positions were recorded with a motion analysis system while the subjects ran along a 25 m runway at a speed of 3.5 m/s. Kinematic variables were analyzed for the stance phase of the right leg. Female runners demonstrated significantly greater peak knee abduction (P<0.05), hip adduction (P<0.01) and internal rotation (P<0.05), whereas male runners demonstrated significantly greater peak rearfoot eversion (P<0.01). The knee abduction angles were positively correlated with hip adduction angles (r=0.49, P<0.05) and negatively correlated with rearfoot eversion (r= −0.69, P<0.001). There was no significant difference in normalised step width between genders (P>0.05). Smaller rearfoot eversion and greater hip adduction related closely to the greater knee abduction as the distal and proximal factors, respectively. These relationships are thought to be the compensatory joint motions in the frontal plane, because there was no significant difference in the normalised step width between females and males. The current results suggest that if the step width is identical, the subjects with greater knee abduction had smaller rearfoot eversion to compensate for greater hip adduction, which were more apparent in females. This explains greater knee abduction found in female runners, which can be linked to a high risk of knee injury.