bluuebunny/crossref_metadata_2025 huggingface dataset:
Constructing School Success
Authors: Mehan Hugh , Villanueva Irene , Hubbard Lea , Lintz Angela , Okamoto Dina
Published: June 2012

How can we bolster the academic success of low achieving students and provide a more egalitarian classroom setting? This book describes the process of 'untracking', an educational reform effort that has prepared students from low income, linguistic, and ethnic minority backgrounds for college. Untracking offers all students the same academically-demanding curriculum while varying the amount of institutional support they receive. Helpful institutional 'scaffolds' teach the hidden curriculum of the school, allowing students to develop an academic identity and build bridges between high school and college. There have been many plans and attempts to reform schools, but few detailed investigations of such efforts. This book is a highly readable account of a successful school reform effort. It provides systematic research results concerning the educational and social consequences of untracking previously low achieving students.
Virtues of the Mind
Authors: Zagzebski Linda Trinkaus
Published: June 2012

Almost all theories of knowledge and justified belief employ moral concepts and forms of argument borrowed from moral theories, but none of them pay attention to the current renaissance in virtue ethics. This remarkable book is the first attempt to establish a theory of knowledge based on the model of virtue theory in ethics. The book develops the concept of an intellectual virtue, and then shows how the concept can be used to give an account of the major concepts in epistemology, including the concept of knowledge. This highly original work of philosophy for professionals will also provide students with an excellent introduction to epistemology, virtue theory, and the relationship between ethics and epistemology.
Modern Compiler Implementation in C
Authors: Appel Andrew W. , Ginsburg Maia
Published: June 2012

This new, expanded textbook describes all phases of a modern compiler: lexical analysis, parsing, abstract syntax, semantic actions, intermediate representations, instruction selection via tree matching, dataflow analysis, graph-coloring register allocation, and runtime systems. It includes good coverage of current techniques in code generation and register allocation, as well as functional and object-oriented languages, that are missing from most books. In addition, more advanced chapters are now included so that it can be used as the basis for a two-semester or graduate course. The most accepted and successful techniques are described in a concise way, rather than as an exhaustive catalog of every possible variant. Detailed descriptions of the interfaces between modules of a compiler are illustrated with actual C header files. The first part of the book, Fundamentals of Compilation, is suitable for a one-semester first course in compiler design. The second part, Advanced Topics, which includes the advanced chapters, covers the compilation of object-oriented and functional languages, garbage collection, loop optimizations, SSA form, loop scheduling, and optimization for cache-memory hierarchies.
Introduction to Stellar Winds
Authors: Lamers Henny J. G. L. M. , Cassinelli Joseph P.
Published: June 2012

This long-awaited graduate textbook, written by two pioneers of the field, is the first to provide a comprehensive introduction to the observations, theories and consequences of stellar winds. The rates of mass loss and the wind velocities are explained from basic physical principles. This book also includes chapters clearly explaining the formation and evolution of interstellar bubbles, and the effects of mass loss on the evolution of high- and low-mass stars. Each topic is introduced simply to explain the basic processes and then developed to provide a solid foundation for understanding current research. This authoritative textbook is designed for advanced undergraduate and graduate students and researchers seeking an understanding of stellar winds and, more generally, supersonic flows from astrophysical objects. It is based on courses taught in Europe and the US over the past twenty years and includes seventy problems (with answers) for coursework or self-study.
Individuals, Institutions, and Markets
Authors: Mantzavinos C.
Published: June 2012

Individuals, Institutions, and Markets offers a theory of how the institutional framework of a society emerges and how markets within institutions work. The book shows that both social institutions, defined as the rules of the game, and exchange processes can be analyzed along a common theoretical structure. Mantzavinos' proposal is that a problem solving model of individual behavior inspired by the cognitive sciences provides such a unifying theoretical structure. Integrating the latest scholarship in economics, sociology, political science, law, and anthropology, Mantzavinos offers a genuine political economy showing how social institutions affect economic outcomes.
Corporate Insolvency Law
Authors: Finch Vanessa
Published: June 2012

The first edition of Corporate Insolvency Law proposed a fundamentally revised concept of insolvency law, intended to serve corporate as well as broader social ends. This second edition takes on board a host of changes that have subsequently reshaped insolvency law and practice, notably the consolidation of the rescue culture in the UK, the rise of the pre-packaged administration and the substantial replacement of administrative receivership with administration. It also considers the implications of recent and dramatic changes in the provision and trading of credit, the movement of an increasing amount of 'insolvency work' to the pre-formal insolvency stage of corporate affairs and the arrival, on the insolvency scene, of a new cadre of specialists in corporate turnaround. Looking to the future, Vanessa Finch argues that changes of approach are needed if insolvency law is to develop with coherence and purpose, and she offers a framework for such an approach.
Effective Negotiation
Authors: Fells Ray
Published: June 2012

Effective Negotiation is a task-oriented and practical resource that provides the skills needed to reach a good agreement. It examines how negotiations work and covers key issues such as trust, power and information exchange. Ray Fells draws on his extensive teaching and research experience to present useful, applicable strategies and advice on managing workplace and business negotiations. Fully revised and updated, this comprehensive second edition boasts new features including chapter summaries, fundamental skills tips and a complete Negotiator's Toolkit. It incorporates up-to-date case studies, new material on mediation and on multiparty negotiations and a new concluding chapter on being an effective negotiator. The companion website, at www.cambridge.edu.au/academic/effective, includes a comprehensive set of lecturer resources, including PowerPoint summaries, negotiation role plays and expanded case material. Effective Negotiation remains an essential resource for students and professionals in the fields of business and management, law, human resource management and employment relations.
Educational Leadership
Authors: Duignan Patrick
Published: June 2012

The second edition of Educational Leadership: Together Creating Ethical Learning Environments is a groundbreaking work at the forefront of current research into the ethical challenges inherent to leadership. Patrick Duignan combines a new perspective of leadership as an influence relationship, with a collective ethic of responsibility. Educational Leadership draws together cutting-edge research, theory and best practice on learning, teaching and leadership to assist leaders and teachers to better understand contemporary educational challenges and respond to them wisely, creatively and effectively. This book is indispensable for all system and educational professionals engaged in policy-making, leadership development, leading learning in schools and those in academe responsible for programs aimed at the improvement of learning, teaching and leadership.
Taking prisoners: reviewing the international humanitarian law grounds for deprivation of liberty by armed opposition groups
Authors: Casalin Deborah
Published: June 2012

While detention by armed opposition groups in non-international armed conflict is a reality that is foreseen and not prohibited by international humanitarian law, the grounds upon which it may take place are not defined. This article looks more closely at the customary international humanitarian law prohibition on arbitrary deprivation of liberty, and how it can apply to armed opposition groups in a manner that makes compliance realistic. It focuses on the legal bases upon which armed opposition groups may detain persons who are taken into custody in order to remove them from hostilities or for security purposes. An approach to detention by armed opposition groups based on the principles of international humanitarian law applicable to international armed conflicts is explored and its limitations defined.
Sensitivity of peatland carbon loss to organic matter quality
Authors: Leifeld Jens , Steffens Markus , Galego‐Sala Angela
Published: June 2012

Peatland soils store substantial amounts of organic matter (OM). During peat formation, easily decomposable OM is preferentially lost and more recalcitrant moieties accumulate. In a peat profile, OM quality thus scales with depth. Drainage and ongoing climate change poses the risk of rapid OM loss when formerly anoxic peat layers oxidize. During peat decomposition, deeper, more recalcitrant peat is exposed to the oxygen‐rich surface, which may influence the decomposition rate. We show that the soil respiration rate of a disturbed temperate peatland is strongly controlled by the peat's quality and especially its polysaccharides content. The polysaccharide content of soil profiles in a wider range of peatland sites with differing degrees of disturbance was inferred by means of solid‐state13C NMR and DRIFT spectroscopy. The data confirmed a strong decline in polysaccharide content with depth and a poor OM quality of surface peat in soils drained decades ago. We combined the evidence from respiration and spectroscopic measurements to deduce the sensitivity of peatland carbon loss with respect to OM quality by scaling measured quality to a 142‐years record of peatland subsidence and carbon loss at one of the sites. According to the functional relationship between quality and respiration, the measured average annual carbon loss rate of 2.5 t C ha−1 at that site was 20 t C ha−1 at the onset of peatland drainage and dropped to less than 1 t C ha−1 in recent times.
Mechanical power input from buoyancy and wind to the circulation in an ocean model
Authors: Saenz J. A. , Hogg A. M. , Hughes G. O. , Griffiths R. W.
Published: June 2012

We make a systematic quantitative comparison of the effects that surface buoyancy forcing and wind stress have on the energy balance of an idealized, rotating, pole‐to‐pole ocean model with a zonally re‐entrant channel in the south, forced by realistic heat (buoyancy) fluxes and wind stresses representative of global climatology. Surface buoyancy fluxes and wind stress forcing are varied independently; both have significant effects on the reservoirs of various forms of energy and the rates of transfer between them. Importantly, we show for the first time that in the ocean, each power input has a positive feedback on the other. Changes in the rate of generation of available potential energy by buoyancy fluxes at the surface lead to similar changes in the rate of conversion of potential energy to kinetic energy by buoyancy forces (sinking) in the interior, and to changes in the rate of generation of kinetic energy by wind stress. Conversely, changes in the rate of generation of kinetic energy by wind stress lead to changes in the rate of generation of available potential energy by buoyancy forcing. We discuss how this feedback is mediated by the circumpolar current, and processes involving buoyancy, mixing and geostrophic balances. Our results support the notion that surface buoyancy forcing, along with wind and tidal forcing, plays an active role in the energy balance of the oceans. The overturning circulation in the oceans is not the result of a single driving force. Rather, it is a manifestation of a complex and subtle balance.
Observational test of interchange instability associated with magnetic dipolarization in the near‐Earth plasma sheet ofr < 12 RE
Authors: Lee D.‐Y. , Ohtani S. , Kim H. S. , Kim K. C.
Published: June 2012

Interchange instability is basically a pressure gradient‐driven mode, and therefore, it may naturally be expected to be triggered in the near‐Earth tail during the growth phase of magnetic dipolarization as the tail field lines become more stretched by an increasing radial pressure gradient. To examine this possibility, we have tested the classic interchange criterion by using the plasma and magnetic field observations from the THEMIS inner tail probes atr < 12 RE. Both the specific events and the statistical results of this study indicate that the stretched tail field configurations during the dipolarization growth phase are actually stable to the interchange mode. Considering that the interchange mode is formally regarded as a special case of the more general ballooning mode, our conclusion of the interchange mode stability prior to the dipolarization onset eliminates one family of the pressure gradient‐driven modes as a possible trigger of dipolarization at the near‐Earth tail. However, interestingly, we find the possibility that sometimes, the near‐tail field configurations can become less stable and even occasionally be unstable after they become rounder through the dipolarization process, although this possibility requires more rigorous test for a solid conclusion.
Tropospheric chemistry of internally mixed sea salt and organic particles: Surprising reactivity of NaCl with weak organic acids
Authors: Laskin Alexander , Moffet Ryan C. , Gilles Mary K. , Fast Jerome D. , Zaveri Rahul A. , Wang Bingbing , Nigge Pascal , Shutthanandan Janani
Published: June 2012

Chemical imaging analysis of internally mixed sea salt/organic particles collected onboard the Department of Energy (DOE) G‐1 aircraft during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) was performed using electron microscopy and X‐ray spectro‐microscopy. Substantial chloride depletion in aged sea salt particles was observed, which could not be explained by the known atmospheric reactivity of sea salt with inorganic nitric and sulfuric acids. We present field evidence that chloride components in sea salt particles may effectively react with organic acids releasing HCl gas to the atmosphere, leaving behind particles depleted in chloride and enriched in the corresponding organic salts. While formation of the organic salts products is not thermodynamically favored for bulk aqueous chemistry, these reactions in aerosol are driven by high volatility and evaporation of the HCl product from drying particles. These field observations were corroborated in a set of laboratory experiments where NaCl particles mixed with organic acids were found to be depleted in chloride. Combined together, the results indicate substantial chemical reactivity of sea salt particles with secondary organics that has been largely overlooked in the atmospheric aerosol chemistry. Atmospheric aging, and in particular hydration‐dehydration cycles of mixed sea salt/organic particles, may result in formation of organic salts that will modify the acidity, hygroscopic, and optical properties of aged particles.
Modeling of temperature and turbidity in a natural lake and a reservoir connected by pumped‐storage operations
Authors: Bonalumi Matteo , Anselmetti Flavio S. , Wüest Alfred , Schmid Martin
Published: June 2012

Pumped‐storage (PS) systems are used to store electric energy as potential energy for release during peak demand. We investigate the impacts of a planned 1000 MW PS scheme connecting Lago Bianco with Lago di Poschiavo (Switzerland) on temperature and particle mass concentration in both basins. The upper (turbid) basin is a reservoir receiving large amounts of fine particles from the partially glaciated watershed, while the lower basin is a much clearer natural lake. Stratification, temperature and particle concentrations in the two basins were simulated with and without PS for four different hydrological conditions and 27 years of meteorological forcing using the software CE‐QUAL‐W2. The simulations showed that the PS operations lead to an increase in temperature in both basins during most of the year. The increase is most pronounced (up to 4°C) in the upper hypolimnion of the natural lake toward the end of summer stratification and is partially due to frictional losses in the penstocks, pumps and turbines. The remainder of the warming is from intense coupling to the atmosphere while water resides in the shallower upper reservoir. These impacts are most pronounced during warm and dry years, when the upper reservoir is strongly heated and the effects are least concealed by floods. The exchange of water between the two basins relocates particles from the upper reservoir to the lower lake, where they accumulate during summer in the upper hypolimnion (10 to 20 mg L−1) but also to some extent decrease light availability in the trophic surface layer.
Chromatin organizer SATB1 is an important determinant of T‐cell differentiation
Authors: Burute Mithila , Gottimukkala Kamal , Galande Sanjeev
Published: June 2012

T‐cell development and differentiation is coordinated by a multitude of signaling molecules and transcription factors that impart distinct functional properties to progenitors. In this review, we focus on the role of the T lineage‐enriched chromatin organizer and regulator SATB1 in T‐cell differentiation. SATB1 mediates Wnt signaling by recruiting β‐catenin to its genomic targets and coordinates T helper type 2 (TH2) differentiation by positively regulating GATA‐3. In contrast, maintenance of regulatory T cell (Treg) functions are dependent on inhibition of SATB1‐mediated modulation of global chromatin organization. We discuss how regulation of the activity of SATB1 has a critical role in driving these two important differentiation pathways in T cells.
Monte Carlo simulation based on dynamic disorder model in organic semiconductors: From coherent to incoherent transport
Authors: Yao Yao , Si Wei , Hou Xiaoyuan , Wu Chang-Qin
Published: June 2012

The dynamic disorder model for charge carrier transport in organic semiconductors has been extensively studied in recent years. Although it is successful on determining the value of bandlike mobility in the organic crystalline materials, the incoherent hopping, the typical transport characteristic in amorphous molecular semiconductors, cannot be described. In this work, the decoherence process is taken into account via a phenomenological parameter, say, decoherence time, and the projective and Monte Carlo method are applied for this model to determine the waiting time and thus the diffusion coefficient. It is obtained that the type of transport is changed from coherent to incoherent with a sufficiently short decoherence time, which indicates the essential role of decoherence time in determining the type of transport in organics. We have also discussed the spatial extent of carriers for different decoherence time, and the transition from delocalization (carrier resides in about 10 molecules) to localization is observed. Based on the experimental results of spatial extent, we estimate that the decoherence time in pentacene has the order of 1 ps. Furthermore, the dependence of diffusion coefficient on decoherence time is also investigated, and corresponding experiments are discussed.
On the origin of the unusual behavior in the stretching of single-stranded DNA
Authors: Toan Ngo Minh , Thirumalai D.
Published: June 2012

Force-extension curves (FECs), which quantify the response of a variety of biomolecules subject to mechanical force (f), are often quantitatively fit using worm-like chain (WLC) or freely jointed chain (FJC) models. These models predict that the chain extension, x, normalized by the contour length increases linearly at small f and at high forces scale as x ∼ (1 − f−α), where α = 0.5 for WLC and unity for FJC. In contrast, experiments on single-stranded DNA (ssDNA) show that over a range of f and ionic concentration, x scales as x ∼ ln f, which cannot be explained using WLC or FJC models. Using theory and simulations we show that this unusual behavior in FEC in ssDNA is due to sequence-independent polyelectrolyte effects. We show that the x ∼ ln f arises because in the absence of force the tangent correlation function, quantifying chain persistence, decays algebraically on length scales on the order of the Debye length. Our theory, which is most appropriate for monovalent salts, quantitatively fits the experimental data and further predicts that such a regime is not discernible in double-stranded DNA.
Interplay between Sb flux and growth temperature during the formation of GaSb islands on GaP
Authors: El Kazzi S. , Desplanque L. , Wallart X. , Wang Y. , Ruterana P.
Published: June 2012

We investigate the influence of the Sb flux on the growth of GaSb islands on a highly mismatched (001) GaP substrate. Between low and medium Sb flux values, standard kinetics drives the GaSb island formation and their relaxation is progressively favored by 90° misfit dislocations at the GaSb/GaP interface. However, under high Sb flux, the GaSb islands are elongated in the [110] direction and their density decreases. Further experiments varying the growth temperature at fixed Sb flux confirm this finding. We relate this observation to an enhancement of Ga diffusion when the effective Sb flux on the surface is increased. This behavior is qualitatively explained by the large cohesive energy of Sb-Sb bonds present on the surface, which impede the Ga adatom incorporation.
Relativistic current collection by a cylindrical Langmuir probe
Authors: Sánchez-Arriaga G. , Sanmartín J. R.
Published: June 2012

The current I to a cylindrical Langmuir probe with a bias Φp satisfying β≡eΦp/mec2∼O(1) is discussed. The probe is considered at rest in an unmagnetized plasma composed of electrons and ions with temperatures kTe∼kTi≪mec2. For small enough radius, the probe collects the relativistic orbital-motion-limited (OML) current IOML, which is shown to be larger than the non-relativistic result; the OML current is proportional to β1/2 and β3/2 in the limits β≪1 and β≫1, respectively. Unlike the non-relativistic case, the electron density can exceed the unperturbed density value. An asymptotic theory allowed to compute the maximum radius of the probe to collect OML current, the sheath radius for probe radius well below maximum and how the ratio I/IOML drops below unity when the maximum radius is exceeded. A numerical algorithm that solves the Vlasov-Poisson system was implemented and density and potential profiles presented. The results and their implications in a possible mission to Jupiter with electrodynamic bare tethers are discussed.
Cross sections of charge exchange and ionization in O8+ +H collision in Debye plasmas
Authors: Pandey M. K. , Lin Y.-C. , Ho Y. K.
Published: June 2012

Charge exchange and ionization processes in O8+ +H collision system in a Debye plasma are studied using the classical trajectory Monte Carlo (CTMC) method in the collision energy ranging from 1 keV/amu to 500 keV/amu. Total charge exchange and ionization cross sections have been determined in both screening and unscreening environments. In the unscreened case, partial cross sections for transfer into individual n shells of the projectile have also been determined. An interesting and remarkable feature of sudden increase in the ionization cross sections at lower velocities is discussed in terms of the CTMC framework. Results are analyzed in light of available theoretical and experimental results. The cross sections dependencies on Debye screening lengths have been investigated, and plasma screening effect on charge exchange and ionization cross sections has been found throughout the collision energies range, but is particularly pronounced at low projectile collision energies. The sudden rise in the ionization cross sections towards lower energies is explained qualitatively in terms of the multiple encounter model.
Semiconductor-metal transition of titanium sesquioxide nanopowder
Authors: Yan Weiwei , Fang Ming , Liu Mao , Kang Shenghong , Wang Ruining , Zhang Lide , Liu Ling
Published: June 2012

Titanium sesquioxide (Ti2O3) nanopowders have been successfully synthesized using TiCl4 assisted hydrogen reduction method from P25 (TiO2) powders at 970 °C. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy reveal its high purity. The temperature dependent XRD, resistance, and infrared absorption investigations exhibit Z-shaped curves (cell parameter a, resistance, and infrared transmittance) indicating the semiconductor-metal transition (SMT) in the range of 135–220 °C. With prolonging the annealing time, the starting temperature of SMT is found to move toward the low-temperature side, and this was also discussed. The c/a ratio alteration is considered to result in the modulation of property. Besides, the results are verified comparing with the theoretical calculation of band structure.
Ultrathin metallic coatings can induce quantum levitation between nanosurfaces
Authors: Boström Mathias , Ninham Barry W. , Brevik Iver , Persson Clas , Parsons Drew F. , Sernelius Bo E.
Published: June 2012

There is an attractive Casimir-Lifshitz force between two silica surfaces in a liquid (bromobenze or toluene). We demonstrate that adding an ultrathin (5–50 Å) metallic nanocoating to one of the surfaces results in repulsive Casimir-Lifshitz forces above a critical separation. The onset of such quantum levitation comes at decreasing separations as the film thickness decreases. Remarkably, the effect of retardation can turn attraction into repulsion. From that we explain how an ultrathin metallic coating may prevent nanoelectromechanical systems from crashing together.
Stress- and Rho-activated ZO-1–associated nucleic acid binding protein binding to p21 mRNA mediates stabilization, translation, and cell survival
Authors: Nie Mei , Balda Maria S. , Matter Karl
Published: June 2012

A central component of the cellular stress response is p21
WAF1/CIP1
, which regulates cell proliferation, survival, and differentiation. Inflammation and cell stress often up-regulate p21 posttranscriptionally by regulatory mechanisms that are poorly understood. ZO-1–associated nucleic acid binding protein (ZONAB)/DbpA is a Y-box transcription factor that is regulated by components of intercellular junctions that are affected by cytokines and tissue damage. We therefore asked whether ZONAB activation is part of the cellular stress response. Here, we demonstrate that ZONAB promotes cell survival in response to proinflammatory, hyperosmotic, and cytotoxic stress and that stress-induced ZONAB activation involves the Rho regulator GEF-H1. Unexpectedly, stress-induced ZONAB activation does not stimulate ZONAB’s activity as a transcription factor but leads to the posttranscriptional up-regulation of p21 protein and mRNA. Up-regulation is mediated by ZONAB binding to specific sites in the 3′-untranslated region of the p21 mRNA, resulting in mRNA stabilization and enhanced translation. Binding of ZONAB to mRNA is activated by GEF-H1 via Rho stimulation and also mediates Ras-induced p21 expression. We thus identify a unique type of stress and Rho signaling activated pathway that drives mRNA stabilization and translation and links the cellular stress response to p21 expression and cell survival.
Wnt/β-catenin and Bmp signals control distinct sets of transcription factors in cardiac progenitor cells
Authors: Klaus Alexandra , Müller Marion , Schulz Herbert , Saga Yumiko , Martin James F. , Birchmeier Walter
Published: June 2012

Progenitor cells of the first and second heart fields depend on cardiac-specific transcription factors for their differentiation. Using conditional mutagenesis of mouse embryos, we define the hierarchy of signaling events that controls the expression of cardiac-specific transcription factors during differentiation of cardiac progenitors at embryonic day 9.0. Wnt/β-catenin and Bmp act downstream of Notch/RBPJ at this developmental stage. Mutation of
Axin2
, the negative regulator of canonical Wnt signaling, enhances Wnt and Bmp4 signals and suffices to rescue the arrest of cardiac differentiation caused by loss of
RBPJ
. Using FACS enrichment of cardiac progenitors in
RBPJ
and
RBPJ/Axin2
mutants, embryo cultures in the presence of the Bmp inhibitor Noggin, and by crossing a
Bmp4
mutation into the
RBPJ/Axin2
mutant background, we show that Wnt and Bmp4 signaling activate specific and nonoverlapping cardiac-specific genes in the cardiac progenitors:
Nkx2-5
,
Isl1
and
Baf60c
are controlled by Wnt/β-catenin, and
Gata4
,
SRF
,
and Mef2c
are controlled by Bmp signaling. Our study contributes to the understanding of the regulatory hierarchies of cardiac progenitor differentiation and outflow tract development and has implications for understanding and modeling heart development.
Predictability of population displacement after the 2010 Haiti earthquake
Authors: Lu Xin , Bengtsson Linus , Holme Petter
Published: June 2012

Most severe disasters cause large population movements. These movements make it difficult for relief organizations to efficiently reach people in need. Understanding and predicting the locations of affected people during disasters is key to effective humanitarian relief operations and to long-term societal reconstruction. We collaborated with the largest mobile phone operator in Haiti (Digicel) and analyzed the movements of 1.9 million mobile phone users during the period from 42 d before, to 341 d after the devastating Haiti earthquake of January 12, 2010. Nineteen days after the earthquake, population movements had caused the population of the capital Port-au-Prince to decrease by an estimated 23%. Both the travel distances and size of people’s movement trajectories grew after the earthquake. These findings, in combination with the disorder that was present after the disaster, suggest that people’s movements would have become less predictable. Instead, the predictability of people’s trajectories remained high and even increased slightly during the three-month period after the earthquake. Moreover, the destinations of people who left the capital during the first three weeks after the earthquake was highly correlated with their mobility patterns during normal times, and specifically with the locations in which people had significant social bonds. For the people who left Port-au-Prince, the duration of their stay outside the city, as well as the time for their return, all followed a skewed, fat-tailed distribution. The findings suggest that population movements during disasters may be significantly more predictable than previously thought.
Calcium homeostasis modulator 1 (CALHM1) is the pore-forming subunit of an ion channel that mediates extracellular Ca
2+
regulation of neuronal excitability
Authors: Ma Zhongming , Siebert Adam P. , Cheung King-Ho , Lee Robert J. , Johnson Brian , Cohen Akiva S. , Vingtdeux Valérie , Marambaud Philippe , Foskett J. Kevin
Published: June 2012

Extracellular Ca
2+
(Ca
2+
o
) plays important roles in physiology. Changes of Ca
2+
o
concentration ([Ca
2+
]
o
) have been observed to modulate neuronal excitability in various physiological and pathophysiological settings, but the mechanisms by which neurons detect [Ca
2+
]
o
are not fully understood. Calcium homeostasis modulator 1 (CALHM1) expression was shown to induce cation currents in cells and elevate cytoplasmic Ca
2+
concentration ([Ca
2+
]
i
) in response to removal of Ca
2+
o
and its subsequent addback. However, it is unknown whether CALHM1 is a pore-forming ion channel or modulates endogenous ion channels. Here we identify CALHM1 as the pore-forming subunit of a plasma membrane Ca
2+
-permeable ion channel with distinct ion permeability properties and unique coupled allosteric gating regulation by voltage and [Ca
2+
]
o
. Furthermore, we show that CALHM1 is expressed in mouse cortical neurons that respond to reducing [Ca
2+
]
o
with enhanced conductance and action potential firing and strongly elevated [Ca
2+
]
i
upon Ca
2+
o
removal and its addback. In contrast, these responses are strongly muted in neurons from mice with
CALHM1
genetically deleted. These results demonstrate that CALHM1 is an evolutionarily conserved ion channel family that detects membrane voltage and extracellular Ca
2+
levels and plays a role in cortical neuronal excitability and Ca
2+
homeostasis, particularly in response to lowering [Ca
2+
]
o
and its restoration to normal levels.
Deletion of periostin reduces muscular dystrophy and fibrosis in mice by modulating the transforming growth factor-β pathway
Authors: Lorts Angela , Schwanekamp Jennifer A. , Baudino Troy A. , McNally Elizabeth M. , Molkentin Jeffery D.
Published: June 2012

The muscular dystrophies are broadly classified as muscle wasting diseases with myofiber dropout due to cellular necrosis, inflammation, alterations in extracellular matrix composition, and fatty cell replacement. These events transpire and progress despite ongoing myofiber regeneration from endogenous satellite cells. The degeneration/regeneration response to muscle injury/disease is modulated by the proinflammatory cytokine transforming growth factor-β (TGF-β), which can also profoundly influence extracellular matrix composition through increased secretion of profibrotic proteins, such as the matricellular protein periostin. Here we show that up-regulation and secretion of periostin is pathological and enhances disease in the δ-sarcoglycan null (

Sgcd
−/−

) mouse model of muscular dystrophy (MD). Indeed, MD mice lacking the
Postn
gene showed dramatic improvement in skeletal muscle structure and function. Mechanistically,
Postn
gene deletion altered TGF-β signaling so that it now enhanced tissue regeneration with reduced levels of fibrosis. Systemic antagonism of TGF-β with a neutralizing monoclonal antibody mitigated the beneficial effects of
Postn
deletion in vivo. These data suggest that periostin functions as a disease determinant in MD by promoting/allowing the pathological effects of TGF-β, suggesting that inhibition of periostin could represent a unique treatment approach.
Purified and synthetic Alzheimer’s amyloid beta (Aβ) prions
Authors: Stöhr Jan , Watts Joel C. , Mensinger Zachary L. , Oehler Abby , Grillo Sunny K. , DeArmond Stephen J. , Prusiner Stanley B. , Giles Kurt
Published: June 2012

The aggregation and deposition of amyloid-β (Aβ) peptides are believed to be central events in the pathogenesis of Alzheimer’s disease (AD). Inoculation of brain homogenates containing Aβ aggregates into susceptible transgenic mice accelerated Aβ deposition, suggesting that Aβ aggregates are capable of self-propagation and hence might be prions. Recently, we demonstrated that Aβ deposition can be monitored in live mice using bioluminescence imaging (BLI). Here, we use BLI to probe the ability of Aβ aggregates to self-propagate following inoculation into bigenic mice. We report compelling evidence that Aβ aggregates are prions by demonstrating widespread cerebral β-amyloidosis induced by inoculation of either purified Aβ aggregates derived from brain or aggregates composed of synthetic Aβ. Although synthetic Aβ aggregates were sufficient to induce Aβ deposition in vivo, they exhibited lower specific biological activity compared with brain-derived Aβ aggregates. Our results create an experimental paradigm that should lead to identification of self-propagating Aβ conformations, which could represent novel targets for interrupting the spread of Aβ deposition in AD patients.
Cofactor molecules maintain infectious conformation and restrict strain properties in purified prions
Authors: Deleault Nathan R. , Walsh Daniel J. , Piro Justin R. , Wang Fei , Wang Xinhe , Ma Jiyan , Rees Judy R. , Supattapone Surachai
Published: June 2012

Prions containing misfolded prion protein (PrP
Sc
) can be formed with cofactor molecules using the technique of serial protein misfolding cyclic amplification. However, it remains unknown whether cofactors materially participate in maintaining prion conformation and infectious properties. Here we show that withdrawal of cofactor molecules during serial propagation of purified recombinant prions caused adaptation of PrP
Sc
structure accompanied by a reduction in specific infectivity of >10
5
-fold, to undetectable levels, despite the ability of adapted “protein-only” PrP
Sc
molecules to self-propagate in vitro. We also report that changing only the cofactor component of a minimal reaction substrate mixture during serial propagation induced major changes in the strain properties of an infectious recombinant prion. Moreover, propagation with only one functional cofactor (phosphatidylethanolamine) induced the conversion of three distinct strains into a single strain with unique infectious properties and PrP
Sc
structure. Taken together, these results indicate that cofactor molecules can regulate the defining features of mammalian prions: PrP
Sc
conformation, infectivity, and strain properties. These findings suggest that cofactor molecules likely are integral components of infectious prions.
Effectiveness of Common Fish Screen Materials to Protect Lamprey Ammocoetes
Authors: Rose Brien P. , Mesa Matthew G.
Published: June 2012

Understanding the effects of irrigation diversions on populations of Pacific lamprey Lampetra tridentata in the Columbia River basin is needed for their recovery. We tested the effectiveness of five common fish screen materials for excluding lamprey ammocoetes: interlock (IL), vertical bar (VB), perforated plate (PP), and 12-gauge and 14-gauge wire cloth (WC12) and (WC14). When fish (28–153 mm) were exposed for 60 min to screen panels perpendicular to an approach velocity of 12 cm/s in a recirculating flume, the percentage of ammocoetes entrained (i.e., passed through the screen) was 26% for the IL, 18% for the PP, 33% for the VB, 62% for the WC14, and 65% for the WC12 screens. For all screens, most fish were entrained within the first 15–20 min. Fish length significantly influenced entrainment, with the PP, VB, and IL screens preventing fish greater than 50–65 mm from entrainment and the WC14 and WC12 screens preventing entrainment of fish greater than 90–110 mm. Fish of all sizes repeatedly became impinged (i.e., contacting the screen for more than 1 s) on the screens, with the frequency of impingement events increasing during the first 5 min and becoming relatively stable thereafter. Impingement ranges were highest on the IL screen (36–62%), lowest on the WC14 and WC12 screens (13–31%), and intermediate on the PP and VB screens (23–54%). However, the WC14 and WC12 screens had fewer and larger fish remaining as time elapsed because so many were entrained. For all screen types, injuries were rare and minor, and no fish died after overnight posttest holding. Our results indicate that wire cloth screens should be replaced, where practical, with perforated plate, vertical bar, or interlocking bar screens to reduce lamprey entrainment at water diversions.

Received October 26, 2011; accepted March 14, 2012
Action–perception coupling in pianists: Learned mappings or spatial musical association of response codes (SMARC) effect?
Authors: Stewart Lauren , Verdonschot Rinus G. , Nasralla Patrick , Lanipekun Jennifer
Published: June 2012

The principle of common coding suggests that a joint representation is formed when actions are repeatedly paired with a specific perceptual event. Musicians are occupationally specialized with regard to the coupling between actions and their auditory effects. In the present study, we employed a novel paradigm to demonstrate automatic action–effect associations in pianists. Pianists and nonmusicians pressed keys according to aurally presented number sequences. Numbers were presented at pitches that were neutral, congruent, or incongruent with respect to pitches that would normally be produced by such actions. Response time differences were seen between congruent and incongruent sequences in pianists alone. A second experiment was conducted to determine whether these effects could be attributed to the existence of previously documented spatial/pitch compatibility effects. In a “stretched” version of the task, the pitch distance over which the numbers were presented was enlarged to a range that could not be produced by the hand span used in Experiment 1. The finding of a larger response time difference between congruent and incongruent trials in the original, standard, version compared with the stretched version, in pianists, but not in nonmusicians, indicates that the effects obtained are, at least partially, attributable to learned action effects.
Uropod elongation is a common final step in leukocyte extravasation through inflamed vessels
Authors: Hyun Young-Min , Sumagin Ronen , Sarangi Pranita P. , Lomakina Elena , Overstreet Michael G. , Baker Christina M. , Fowell Deborah J. , Waugh Richard E. , Sarelius Ingrid H. , Kim Minsoo
Published: June 2012

The efficient trafficking of immune cells into peripheral nonlymphoid tissues is key to enact their protective functions. Despite considerable advances in our understanding of cell migration in secondary lymphoid organs, real-time leukocyte recruitment into inflamed tissues is not well characterized. The conventional multistep paradigm of leukocyte extravasation depends on CD18 integrin–mediated events such as rapid arrest and crawling on the surface of the endothelium and transmigration through the endothelial layer. Using enhanced three-dimensional detection of fluorescent CD18 fusion proteins in a newly developed knockin mouse, we report that extravasating leukocytes (neutrophils, monocytes, and T cells) show delayed uropod detachment and become extremely elongated before complete transmigration across the endothelium. Additionally, these cells deposit CD18+ microparticles at the subendothelial layer before retracting the stretched uropod. Experiments with knockout mice and blocking antibodies reveal that the uropod elongation and microparticle formation are the result of LFA-1–mediated adhesion and VLA-3–mediated cell migration through the vascular basement membrane. These findings suggest that uropod elongation is a final step in the leukocyte extravasation cascade, which may be important for precise regulation of leukocyte recruitment into inflamed tissues.
SCFβ-TRCP suppresses angiogenesis and thyroid cancer cell migration by promoting ubiquitination and destruction of VEGF receptor 2
Authors: Shaik Shavali , Nucera Carmelo , Inuzuka Hiroyuki , Gao Daming , Garnaas Maija , Frechette Gregory , Harris Lauren , Wan Lixin , Fukushima Hidefumi , Husain Amjad , Nose Vania , Fadda Guido , Sadow Peter M. , Goessling Wolfram , North Trista , Lawler Jack , Wei Wenyi
Published: June 2012

The incidence of human papillary thyroid cancer (PTC) is increasing and an aggressive subtype of this disease is resistant to treatment with vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor. VEGFR2 promotes angiogenesis by triggering endothelial cell proliferation and migration. However, the molecular mechanisms governing VEGFR2 stability in vivo remain unknown. Additionally, whether VEGFR2 influences PTC cell migration is not clear. We show that the ubiquitin E3 ligase SCFβ-TRCP promotes ubiquitination and destruction of VEGFR2 in a casein kinase I (CKI)–dependent manner. β-TRCP knockdown or CKI inhibition causes accumulation of VEGFR2, resulting in increased activity of signaling pathways downstream of VEGFR2. β-TRCP–depleted endothelial cells exhibit enhanced migration and angiogenesis in vitro. Furthermore, β-TRCP knockdown increased angiogenesis and vessel branching in zebrafish. Importantly, we found an inverse correlation between β-TRCP protein levels and angiogenesis in PTC. We also show that β-TRCP inhibits cell migration and decreases sensitivity to the VEGFR2 inhibitor sorafenib in poorly differentiated PTC cells. These results provide a new biomarker that may aid a rational use of tyrosine kinase inhibitors to treat refractory PTC.
Mutant p53: one name, many proteins
Authors: Freed-Pastor William A. , Prives Carol
Published: June 2012

There is now strong evidence that mutation not only abrogates p53 tumor-suppressive functions, but in some instances can also endow mutant proteins with novel activities. Such neomorphic p53 proteins are capable of dramatically altering tumor cell behavior, primarily through their interactions with other cellular proteins and regulation of cancer cell transcriptional programs. Different missense mutations in p53 may confer unique activities and thereby offer insight into the mutagenic events that drive tumor progression. Here we review mechanisms by which mutant p53 exerts its cellular effects, with a particular focus on the burgeoning mutant p53 transcriptome, and discuss the biological and clinical consequences of mutant p53 gain of function.
Quit your YAPing: a new target for cancer therapy: Figure 1.
Authors: Stanger Ben Z.
Published: June 2012

The Hippo pathway is an evolutionarily conserved signaling module that plays multiple roles in embryonic development. Components of the pathway, which includes a kinase cascade and a downstream complex composed of YAP and TEAD transcription factors, are dysregulated in a significant fraction of human cancers. In this issue of Genes & Development, Liu-Chittenden and colleagues (pp. 1300–1305) use genetic and pharmacological means to disrupt the active YAP–TEAD complex. As this intervention impedes tumorigenesis in the liver with no apparent effect on normal liver homeostasis, the work paves the way for the development of new strategies to target this pervasive oncogenic pathway.
Quantitative small-angle scattering on mesoporous silica powders: from morphological features to specific surface estimation
Authors: Cambedouzou Julien , Diat Olivier
Published: June 2012

A comprehensive method allowing experimentalists to perform a quantitative analysis of small-angle scattering patterns of powdered mesoporous materials of hexagonal symmetry is presented in this paper. Thanks to the rigorous processing of experimental data, and to a straightforward model for the small-angle scattering data simulation, the direct comparison of experimental and calculated patterns is made without any artificial background correction oradhocfunction. This allows the specific surface of mesopores to be estimated without resorting to other methods such as adsorption methods. This approach and its precision are discussed on the basis of the analysis of two real samples.
Structural analysis of magnetic nanocrystals embedded in silicate glasses by anomalous small-angle X-ray scattering
Authors: Raghuwanshi Vikram Singh , Tatchev Dragomir , Haas Sylvio , Harizanova Ruzha , Gugov Ivailo , Rüssel Christian , Hoell Armin
Published: June 2012

The present work reports the structural analysis of magnetic nanocrystals of Fe- and Mn-containing phases formed during annealing of the glass 13.6Na2O–62.9SiO2–8.5MnO–15.0Fe2O3−x(mol%) at 823 K for different periods of time. X-ray diffraction investigation shows the formation of a mixture of MnFe2O4and Fe3O4phases. Furthermore, small-angle X-ray scattering and anomalous small-angle X-ray scattering (ASAXS) experiments were used to extract quantitative information about the structure of the formed nano-sized crystals, as well as their phase compositions, volume fractions and size distributions. ASAXS analysis reveals the formation of spherical core–shell particles with the size of the particles between 10 and 50 nm. The concentrations of iron atoms in the core are higher than those in the shell and in the remaining matrix. With increasing annealing time, the ratio of Mn to Fe increases in the nanoparticles and the crystalline phase moves toward the pure jacobsite phase. Evaluated compositions reveal the presence of SiO2in the shell. This shell acts as a diffusion barrier for the nanocrystal-forming ions, and the growth of the particles is kinetically constrained.