bluuebunny/crossref_metadata_2025 huggingface dataset:
On the role of the ambient fluid on gravitational granular flow dynamics
Authors: MERUANE C. , TAMBURRINO A. , ROCHE O.
Published: April 2010

The effects of the ambient fluid on granular flow dynamics are poorly understood and commonly ignored in analyses. In this article, we characterize and quantify these effects by combining theoretical and experimental analyses. Starting with the mixture theory, we derive a set of two-phase continuum equations for studying a compressible granular flow composed of homogenous solid particles and a Newtonian ambient fluid. The role of the ambient fluid is then investigated by studying the collapse and spreading of two-dimensional granular columns in air or water, for different solid particle sizes and column aspect (height to length) ratios, in which the front speed is used to describe the flow. The combined analysis of experimental measurements and numerical solutions shows that the dynamics of the solid phase cannot be explained if the hydrodynamic fluid pressure and the drag interactions are not included in the analysis. For instance, hydrodynamic fluid pressure can hold the reduced weight of the solids, thus inducing a transition from dense-compacted to dense-suspended granular flows, whereas drag forces counteract the solids movement, especially within the near-wall viscous layer. We conclude that in order to obtain a realistic representation of gravitational granular flow dynamics, the ambient fluid cannot be neglected.
Numerical computation of the domain of operation of an electrospray of a very viscous liquid
Authors: HIGUERA F. J.
Published: April 2010

A numerical study is carried out of the injection of a very viscous liquid of small electrical conductivity at a constant flow rate through an orifice in a metallic plate under the action of an electric field. The conditions under which the injected liquid can form an elongated meniscus with a thin jet emanating from its tip are investigated by computing the flow, the electric field and the transport of electric charge in the meniscus and a leading region of the jet. A stationary solution is found only for values of the flow rate above a certain minimum. At moderate values of the applied field, this minimum flow rate decreases when the applied field or the conductivity of the liquid increase. The electric shear stress acting on the surface of the liquid is not able to drive the liquid into the jet at flow rates smaller than the minimum while, for any flow rate higher than the minimum, the transfer of electric current to the surface may occur in a slender region of the jet where charge relaxation effects are small and the field induced by the electric charge of the jet is important. At high values of the applied field, the flow rate must be higher than another minimum, which increases with the applied field, in order for the viscous stress to balance the strong electric stress acting on the meniscus. The two conditions taken together determine lower and upper bounds for the applied field at a given flow rate, but the value of the applied field at which a stationary jet is first established when this parameter is gradually increased is higher than the lower bound, leading to hysteresis. When the liquid is electrosprayed in a surrounding dielectric fluid, the viscous shear stress that this fluid exerts on the surface of the jet eventually balances the electric shear stress and stops the continuous stretching of the jet. A fraction of the conduction current is left in the jet when the effect of the outer liquid comes into play in the region where this current is transferred to the surface, and no stationary solution is found above a maximum flow rate that decreases when the viscosity of the outer liquid increases or the applied field decreases. Order of magnitude estimates of the electric current and the conditions in the current transfer region are worked out.
Transient Rayleigh–Bénard–Marangoni convection due to evaporation: a linear non-normal stability analysis
Authors: DOUMENC F. , BOECK T. , GUERRIER B. , ROSSI M.
Published: April 2010

The convective instability in a plane liquid layer with time-dependent temperature profile is investigated by means of a general method suitable for linear stability analysis of an unsteady basic flow. The method is based on a non-normal approach, and predicts the onset of instability, critical wavenumber and time. The method is applied to transient Rayleigh–Bénard–Marangoni convection due to cooling by evaporation. Numerical results as well as theoretical scalings for the critical parameters as function of the Biot number are presented for the limiting cases of purely buoyancy-driven and purely surface-tension-driven convection. Critical parameters from calculations are in good agreement with those from experiments on drying polymer solutions, where the surface cooling is induced by solvent evaporation.
Experimental and theoretical study of vibration-induced thermal convection in low gravity
Authors: SHEVTSOVA VALENTINA , RYZHKOV ILYA I. , MELNIKOV DENIS E. , GAPONENKO YURI A. , MIALDUN ALIAKSANDR
Published: April 2010

Vibrations acting on a fluid with density gradient induced by temperature variations can cause relative flows. High-frequency vibration leads to the appearance of time-averaged (mean) flows (or streaming flows), which can essentially affect heat and mass transfer processes. This phenomenon is most pronounced in the absence of other external forces (in particular, static gravity). In this work, an extensive experimental and computational study of thermal vibrational convection in a reduced-gravity environment of a parabolic flight is performed. The transient evolution of the temperature field in a cubic cell subjected to translational vibration is investigated by optical digital interferometry. The mean flow structures previously reported in numerical studies are confirmed. The transition from four-vortex flow to a pattern with a large diagonal vortex and two small vortices is observed in the transient state. The experiments reveal a significant enhancement of heat transfer by vibrational mean flows with increasing the vibrational strength. Three-dimensional direct numerical simulation with real microgravity profile and two-dimensional numerical modelling based on averaging approach provide a very good agreement with the experimental results. The influence of residual gravity on heat transfer and bifurcation scenario is first investigated numerically and correlated with the experimental data. It is demonstrated that gravity effects on non-uniformly heated fluids can be reproduced in weightlessness by applying vibrations to the system.
Flow regimes in a plane Couette flow with system rotation
Authors: TSUKAHARA T. , TILLMARK N. , ALFREDSSON P. H.
Published: April 2010

Flow states in plane Couette flow in a spanwise rotating frame of reference have been mapped experimentally in the parameter space spanned by the Reynolds number and rotation rate. Depending on the direction of rotation, the flow is either stabilized or destabilized. The experiments were made through flow visualization in a Couette flow apparatus mounted on a rotating table, where reflected flakes are mixed with the water to visualize the flow. Both short- and long-time exposures have been used: the short-time exposure gives an instantaneous picture of the turbulent flow field, whereas the long-time exposure averages the small, rapidly varying scales and gives a clearer representation of the large scales. A correlation technique involving the light intensity of the photographs made it possible to obtain, in an objective manner, both the spanwise and streamwise wavelengths of the flow structures. During these experiments 17 different flow regimes have been identified, both laminar and turbulent with and without roll cells, as well as states that can be described as transitional, i.e. states that contain both laminar and turbulent regions at the same time. Many of these flow states seem to be similar to those observed in Taylor–Couette flow.
Cutting the chorda tympani: not just a matter of taste
Authors: Guinand N , Just T , Stow N W , Van H Cao , Landis B N
Published: April 2010

Introduction:

Chorda tympani injury as a complication of middle-ear surgery has been extensively studied with regard to its effects upon taste. However, the chorda tympani also carries parasympathetic fibres to the salivary glands of the oral cavity. To date, little has been reported about the effect of chorda tympani section upon salivary function.

Setting:

Tertiary care centre.

Material and methods:

We report a case series of three patients with bilateral chorda tympani lesions. Chorda tympani function was assessed using ‘taste strips’ and unstimulated sialometry. A careful history of oral symptoms was taken.

Results:

All patients showed transient or permanent bilateral ageusia of the anterior two-thirds of the tongue, and a decreased resting salivary flow rate. In addition, all patients suffered from transient or persistent, distressing xerostomia.

Conclusion:

Taste disorders may occur after middle-ear surgery but they are mostly transient, even when the chorda tympani nerves are sectioned bilaterally. In contrast, bilateral chorda tympani lesions may lead to severe, persistent and distressing xerostomia. Based on this neglected aspect of chorda tympani function, we emphasise the importance of preserving the chorda tympani whenever possible.
Protection of tympanomeatal flaps using Visibility Background Material
Authors: Oozeer N B , Iyer A
Published: April 2010

Background:

Over the years, various materials have been used by otologists to protect tympanomeatal flaps from damage by suction equipment or drills.

Objective:

This report aims to describe the use of Mercian's Visibility Background Material®(an inert, silicone-based material licensed for use in the human body, which does not get caught in drill flukes) to protect tympanomeatal flaps.

Conclusion:

We have used this material for over 12 months, without any complications.
The floating C-Place node in Latin
Authors: CSER ANDRÁS
Published: April 2010

In this paper it is argued that there existed, in a certain period of the history of Latin, a floating C-Place node in some lexical items in word- and stem-initial position. Notably, this was involved in the phonological representation of the words written – in an archaising fashion – with initial 〈gn〉. Based on a thorough analysis of the Brepols Corpus (CLCLT-5) it is demonstrated that the diachronic distribution of the prefixed forms of 〈gn〉-initial stems shows restrictions that can only be explained if one assumes a geometric representation involving a floating C-Place node that remained in the place of the original velar stop inherited from Proto-Indo-European. By classical times this floating node was also lost, and thus the possibilities for combining prefixes with original 〈gn〉-initial stems expanded.
Identification and channel characteristics of cetacean hotspots in waterways of the eastern Sundarbans mangrove forest, Bangladesh
Authors: Smith Brian D. , Diyan M. Abdullah Abu , Mowgli Mansur Rubaiyat , Fahrni Mansur Elisabeth , Ahmed Benazir
Published: April 2010

Sightings data of two freshwater-dependent cetaceans, the Ganges River dolphin Platanista gangetica gangetica and Irrawaddy dolphin Orcaella brevirostris, were recorded by captains of three nature tourism vessels operating in waterways of the eastern Sundarbans mangrove forest, Bangladesh. These data were used to investigate channel-type preferences and identify cetacean hotspots according to a scoring system based on group, individual and calf encounter rates, the co-occurrence of both species, and encounter rates in neighbouring segments recorded during monsoon, post-monsoon and dry seasons. Six 5-km segments were identified for priority conservation attention from a total of 38 that were surveyed on at least three occasions during each season. An investigation of habitat preferences evaluated 5-km segments that had been surveyed on five or more occasions (n = 69) and assigned them to one of 12 categories defined by channel width, sinuosity and the number of large and small confluences. Significant differences were found between observed and expected frequencies of occurrence in the different segment categories for Ganges River dolphin groups and individuals and for Irrawaddy dolphin individuals. Both Ganges River and Irrawaddy dolphins selected channels with more than two small confluences or at least one large confluence. Understanding the preferred habitat and identifying hotspots of freshwater-dependent cetaceans in the Sundarbans is the first step of a planning process for the potential establishment of a network of protected waterways for these threatened species.
Conservation planning for a widespread, threatened species: WWF and the African elephantLoxodonta africana
Authors: Stephenson Peter J. , Ntiamoa-Baidu Yaa
Published: April 2010

In a case study of conservation planning by a conservation organization working at a continental scale we examine how WWF identified and prioritized its African elephantLoxodonta africanaconservation activities. We (1) review lessons learnt from previous work, (2) identify priority landscapes using biological criteria (e.g. population size and viability) and institutional criteria (e.g. feasibility, sustainability and cost-effectiveness of WWF interventions), and (3) conduct a threat analysis and review of national and subregional action plans. We suggest that species action plans should use priority-setting criteria that focus on conserving the largest and most viable populations at the subspecies level. Clear definition of geographical priorities helps an organization focus its resources and assists monitoring. Species action plans should also take account of plans developed by governments and other stakeholders. Conservation agencies wishing to select which landscapes to invest in for a given species or subspecies could then consider institutional prioritization criteria, such as those used by WWF for the African elephant. This would allow them to invest pragmatically in conservation that has a higher chance of success than work planned solely through scientific analysis. Ultimately, however, no species action plan will succeed unless it has the resources necessary for implementation and the key stakeholders work together in partnership.
Human–wildlife conflict in Mozambique: a national perspective, with emphasis on wildlife attacks on humans
Authors: Dunham Kevin M. , Ghiurghi Andrea , Cumbi Rezia , Urbano Ferdinando
Published: April 2010

Human–wildlife conflicts are common across Africa. In Mozambique, official records show that wildlife killed 265 people during 27 months (July 2006 to September 2008). CrocodileCrocodylus niloticus, lionPanthera leo, elephantLoxodonta africanaand hippopotamusHippopotamus amphibiuscaused most deaths but crocodiles were responsible for 66%. Crocodile attacks occurred across Mozambique but 53% of deaths occurred in districts bordering Lake Cabora Bassa and the Zambezi River. Hippopotamus attacks were also concentrated here. Lion attacks occurred mainly in northern Mozambique and, while people were attacked by elephants across the country, 67% of deaths occurred in northern Mozambique. Attacks by lions, elephants or hippopotamuses were relatively rare but additional data will probably show that attacks by these species are more widespread than the preliminary records suggest. BuffaloSyncerus caffer, hyaenaCrocuta crocutaand leopardPanthera parduswere minor conflict species. Good land-use planning, a long-term solution to many conflicts, is particularly relevant in Mozambique, where the crocodile and hippopotamus populations of protected areas are often in rivers that border these areas, and cause conflicts outside them, and where people commonly live within protected areas. Poverty may prompt fishermen to risk crocodile attack by entering rivers or lakes. The high incidence of conflicts near Limpopo and South Africa’s Kruger National Parks (both within the Great Limpopo Transfrontier Conservation Area) highlights the problems created for people by facilitating the unrestricted movement of wildlife between protected areas across their land.
A tale of three villages: choosing an effective method for assessing poaching levels in western Serengeti, Tanzania
Authors: Knapp Eli J. , Rentsch Dennis , Schmitt Jennifer , Lewis Claire , Polasky Stephen
Published: April 2010

Poaching for bushmeat is a major problem for conservation of wildlife populations in many parts of Africa, including the Serengeti ecosystem in Tanzania. However, the severity of the poaching problem is often unclear because of a lack of accurate data. Directly asking people to self-report illegal activity faces the obvious problem of under-reporting. Use of arrest records from anti-poaching patrols may reflect levels of poaching activity but could also be driven by funding and quality of anti-poaching efforts. A third method, assessing poaching by asking about bushmeat consumption, is indirect, possibly subject to under-reporting, and also subject to limits on the accuracy of memory of respondents. We compare rates of poaching derived by self-assessment of poaching activities (based on household interviews), dietary recall of bushmeat consumption over a variety of time frames, and arrest records from anti-poaching units. We apply these three methods to assess poaching activities in three villages bordering protected areas on the western boundary of Serengeti National Park. Our results showed that dietary recall of bushmeat consumption and arrest records indicated similar patterns of poaching across the three villages but self-reporting differed significantly. There appear to be significant advantages to coupling results from dietary recall of bushmeat consumption and arrest records to estimate the level of poaching activity. In situations where reliable data from anti-poaching units are unavailable, cost-effective data collection of bushmeat consumption will provide a viable alternative to assess levels of poaching involvement of villages that border protected areas.
Conservation initiatives for an endangered migratory passerine: field propagation and release
Authors: Nichols Rina K. , Steiner Jessica , Woolaver Lance G. , Williams Elaine , Chabot Amy A. , Tuininga Ken
Published: April 2010

The term ‘field propagation and release’ refers to the breeding of captive adults in large field enclosures, allowing them to raise their young, and then releasing those young from that location. This technique is currently being implemented in Canada as one of several recovery tools for the endangered eastern loggerhead shrikeLanius ludovicianus migrans. During 2001–2007 a total of 360 shrike fledglings were produced in field propagation enclosures and 301 were released from these enclosures. Annual return rates of birds released since 2004 are 2–6.6%. Seventeen released birds have been re-sighted, including 10 birds that have returned to the breeding grounds the following season to produce young with wild mates. The high annual return rate of release birds and the successful integration of these birds into the wild breeding population represent important milestones for the recovery of this population. The management technique we describe here has the potential to be applicable to other species that require natural habitat for breeding and/or are reliant on a suite of parent-learned behaviours that cannot be accommodated for or adequately replicated within intensive close captive-breeding or hand-rearing conditions.
Problems for moral/natural supervenience
Authors: ALEXANDER DAVID E.
Published: April 2010

‘Everyone agrees that the moral features of thingssuperveneon their natural features’ (Smith (1994), 22). Everyone is wrong, or so I will argue. In the first section, I explain the version of moral supervenience that Smith and others argue everyone should accept. In the second section, I argue that the mere conceptual possibility of a divine command theory of morality (DCT) is sufficient to refute the version of moral supervenience under consideration. Lastly, I consider and respond to two objections, showing, among other things, that while DCT is sufficient to refute this version of moral supervenience it is not necessary.
Can arguments boost warrant for Christian belief? Warrant boosting and the primacy of divine revelation
Authors: DILLER KEVIN S.
Published: April 2010

It is well known that in Reformed circles there is significant doubt about the extent of the role natural theology might play in warranting Christian belief. I argue that even if we accept the core theological reservations and philosophical commitments shared by the likes of Karl Barth and Reformed epistemologists, there remains room for the arguments of natural theology to serve a vital, positive function. I offer a proposal for how we might think about the co-ordination of multiple sources of warrant for Christian belief such that arguments function as catalysts to or extensions of the deliverances of faith.
Composition models of the incarnation: unity and unifying relations
Authors: MARMODORO ANNA , HILL JONATHAN
Published: April 2010

In this paper we investigate composition models of incarnation, according to which Christ is a compound of qualitatively and numerically different constituents. We focus on three-part models, according to which Christ is composed of a divine mind, a human mind, and a human body. We consider four possible relational structures that the three components could form. We argue that a ‘hierarchy of natures’ model, in which the human mind and body are united to each other in the normal way, and in which they are jointly related to the divine mind by the relation of co-action, is the most metaphysically plausible model. Finally, we consider the problem of how Christ can be a single person even when his components may be considered persons. We argue that an Aristotelian metaphysics, according to which identity is a matter of function, offers a plausible solution: Christ's components may acquire a radically new identity through being parts of the whole, which enables them to be reidentifiedasparts, not persons.
From restricted to full omniscience
Authors: PRUSS ALEXANDER R.
Published: April 2010

Some, notably Peter van Inwagen, in order to avoid problems with free will and omniscience, replace the condition that an omniscient being knows all true propositions with a version of the apparently weaker condition that an omniscient being knows all knowable true propositions. I shall show that the apparently weaker condition, when conjoined with uncontroversial claims and the logical closure of an omniscient being's knowledge, still yields the claim that an omniscient being knows all true propositions.
MIXED NORMAL INFERENCE ON MULTICOINTEGRATION
Authors: Boswijk H. Peter
Published: April 2010

Asymptotic likelihood analysis of cointegration inI(2) models (see Johansen, 1997, 2006; Boswijk, 2000; Paruolo, 2000) has shown that inference on most parameters is mixed normal, implying hypothesis test statistics with an asymptoticχ2null distribution. The asymptotic distribution of the multicointegration parameter estimator so far has been characterized by a Brownian motion functional, which has been conjectured to have a mixed normal distribution, based on simulations. The present note proves this conjecture.
Variability, negative evidence, and the acquisition of verb argument constructions
Authors: PERFORS AMY , TENENBAUM JOSHUA B. , WONNACOTT ELIZABETH
Published: April 2010

We present a hierarchical Bayesian framework for modeling the acquisition of verb argument constructions. It embodies a domain-general approach to learning higher-level knowledge in the form of inductive constraints (or overhypotheses), and has been used to explain other aspects of language development such as the shape bias in learning object names. Here, we demonstrate that the same model captures several phenomena in the acquisition of verb constructions. Our model, like adults in a series of artificial language learning experiments, makes inferences about the distributional statistics of verbs on several levels of abstraction simultaneously. It also produces the qualitative learning patterns displayed by children over the time course of acquisition. These results suggest that the patterns of generalization observed in both children and adults could emerge from basic assumptions about the nature of learning. They also provide an example of a broad class of computational approaches that can resolve Baker's Paradox.
Long object shift and reflexives
Authors: Heinat Fredrik
Published: April 2010

This short communication is concerned with long object shift of reflexives in Swedish. Only 3rd person reflexives can shift across their antecedent. For some reason this is possible even if the antecedent is 1st or 2nd person as well, but certain requirements on the antecedent are necessary. This paper shows that neither a purely syntactic nor a purely semantic analysis can account for all the facts. Instead the best analysis seems to be one that makes use of Bonet's (1995) post-syntactic morphological processes: feature delinking, feature erasure and feature insertion.
Maintaining independence in older people
Authors: Beswick AD , Gooberman-Hill R , Smith A , Wylde V , Ebrahim S
Published: April 2010

Appropriate social and medical interventions may help maintain independence in older people. Determinants of functional decline, disability and reduced independence are recognized and specific interventions target the treatment of clinical conditions, multiple health problems and geriatric conditions, prevention of falls and fractures, and maintenance of physical and cognitive function and social engagement.

Preventive strategies to identify and treat diverse unmet needs of older people have been researched extensively. We reviewed systematically recent randomized controlled trials evaluating these ‘complex’ interventions and incorporated the findings of 21 studies into an established meta-analysis that included 108,838 people in 110 trials. There was an overall benefit of complex interventions in helping older people to live at home, explained by reduced nursing home admissions rather than death rates. Hospital admissions and falls were also reduced in intervention groups. Benefits were largely restricted to earlier studies, perhaps reflecting general improvements in health and social care for older people. The wealth of high-quality trial evidence endorses the value of preventive strategies to help maintain independence in older people.
Imagining European Identity: French Elites and the American Challenge in the Pompidou–Nixon Era
Authors: GFELLER AURÉLIE ÉLISA
Published: April 2010

Charles de Gaulle has cast a long shadow over French political history and history writing. In exploring the French response to the United States' 1973 ‘Year of Europe’ initiative, this article challenges the dominant scholarly paradigm, which emphasises continuity between the 1960s and the 1970s. Drawing on a wide range of French and US archives, it demonstrates that renewed concerns about US power spurred the French elites both to reappraise the value of collective European action in foreign policy and to foster a pioneering concept: a politically anchored – as opposed to a geographically circumscribed – ‘European identity’.
Behavioral Activation for Treatment of PTSD and Depression in an Iraqi Combat Veteran with Multiple Physical Injuries
Authors: Turner Aaron P. , Jakupcak Matthew
Published: April 2010

Background: Physical injury and psychological trauma associated with combat in the wars in Iraq and Afghanistan frequently lead to a constellation of symptoms including pain, post traumatic stress disorder (PTSD), and depression. Method: This single case study describes the application of a behaviorally-based psychotherapy known as behavioral activation for the treatment of post traumatic stress disorder (PTSD) and depressive symptoms in a recent combat veteran with multiple physical injuries sustained from a blast injury. Treatment was provided concurrently with other rehabilitation services and consisted of weekly individual sessions for 4 months, followed by monthly sessions for 4 months. Results: Clinically significant reductions in PTSD and depressive symptoms were noted between baseline and 1 year follow-up. Conclusion: Preliminary evidence from this case suggests that behavioral activation may be a promising treatment for PTSD and depression, and can be readily tailored to individuals with physical limitations such as pain and mobility restriction. Treatment can be provided in the context of concurrent interdisciplinary medical and rehabilitation care.
Gray matter correlates of set-shifting among neurodegenerative disease, mild cognitive impairment, and healthy older adults
Authors: PA JUDY , POSSIN KATHERINE L. , WILSON STEPHEN M. , QUITANIA LOVINGLY C. , KRAMER JOEL H. , BOXER ADAM L. , WEINER MICHAEL W. , JOHNSON JULENE K.
Published: April 2010

There is increasing recognition that set-shifting, a form of cognitive control, is mediated by different neural structures. However, these regions have not yet been carefully identified as many studies do not account for the influence of component processes (e.g., motor speed). We investigated gray matter correlates of set-shifting while controlling for component processes. Using the Design Fluency (DF), Trail Making Test (TMT), and Color Word Interference (CWI) subtests from the Delis-Kaplan Executive Function System (D-KEFS), we investigated the correlation between set-shifting performance and gray matter volume in 160 subjects with neurodegenerative disease, mild cognitive impairment, and healthy older adults using voxel-based morphometry. All three set-shifting tasks correlated with multiple, widespread gray matter regions. After controlling for the component processes, set-shifting performance correlated with focal regions in prefrontal and posterior parietal cortices. We also identified bilateral prefrontal cortex and the right posterior parietal lobe as common sites for set-shifting across the three tasks. There was a high degree of multicollinearity between the set-shifting conditions and the component processes of TMT and CWI, suggesting DF may better isolate set-shifting regions. Overall, these findings highlight the neuroanatomical correlates of set-shifting and the importance of controlling for component processes when investigating complex cognitive tasks. (JINS, 2010, 16, 640–650.)
Predicting cognitive decline and conversion to Alzheimer’s disease in older adults using the NAB List Learning test
Authors: GAVETT BRANDON E. , OZONOFF AL , DOKTOR VLADA , PALMISANO JOSEPH , NAIR ANIL K. , GREEN ROBERT C. , JEFFERSON ANGELA L. , STERN ROBERT A.
Published: April 2010

To validate the Neuropsychological Assessment Battery (NAB) List Learning test as a predictor of future multi-domain cognitive decline and conversion to Alzheimer’s disease (AD), participants from a longitudinal research registry at a national AD Center were, at baseline, assigned to one of three groups (control, mild cognitive impairment [MCI], or AD), based solely on a diagnostic algorithm for the NAB List Learning test (Gavett et al., 2009), and followed for 1–3 years. Rate of change on common neuropsychological tests and time to convert to a consensus diagnosis of AD were evaluated to test the hypothesis that these outcomes would differ between groups (AD>MCI>control). Hypotheses were tested using linear regression models (n = 251) and Cox proportional hazards models (n = 265). The AD group declined significantly more rapidly than controls on Mini-Mental Status Examination (MMSE), animal fluency, and Digit Symbol; and more rapidly than the MCI group on MMSE and Hooper Visual Organization Test. The MCI group declined more rapidly than controls on animal fluency and CERAD Trial 3. The MCI and AD groups had significantly shorter time to conversion to a consensus diagnosis of AD than controls. The predictive validity of the NAB List Learning algorithm makes it a clinically useful tool for the assessment of older adults. (JINS, 2010, 16, 651–660.)
LAND REFORMS AND ECONOMIC DEVELOPMENT
Authors: Gersbach Hans , Siemers Lars-H. R.
Published: April 2010

We examine the nexus between land transfers and human capital formation. A sequence of land redistributions enables the beneficiaries to educate their children and thus to escape from poverty. A successful land reform allows the transition of a society from an agriculture-based state of poverty to a human capital–based developed economy. We find that a temporary state of inequality among the poor is unavoidable. Finally, we discuss the political economy of land reform, whether access to land markets should be allowed for beneficiaries of land reforms, and property rights issues.
EXCHANGE RATE DYNAMICS, ASSET MARKET STRUCTURE, AND THE ROLE OF THE TRADE ELASTICITY
Authors: Thoenissen Christoph
Published: April 2010

A canonical flexible-price international real–business cycle model with incomplete financial markets can address the exchange rate–volatility puzzle, the exchange rate–persistence puzzle, and the consumption real–exchange rate anomaly, as well as the quantity anomaly. Crucial for the success of the model is the choice of the elasticity of substitution between home and foreign produced goods. The paper shows that the range of this parameter that allows the model to address these international macroeconomics anomalies is very narrow. Furthermore, the paper highlights an anomalous relationship between real–exchange rate persistence and the elasticity of substitution between home- and foreign-produced goods.
Nanoscale X-Ray Microscopic Imaging of Mammalian Mineralized Tissue
Authors: Andrews Joy C. , Almeida Eduardo , van der Meulen Marjolein C.H. , Alwood Joshua S. , Lee Chialing , Liu Yijin , Chen Jie , Meirer Florian , Feser Michael , Gelb Jeff , Rudati Juana , Tkachuk Andrei , Yun Wenbing , Pianetta Piero
Published: April 2010

A novel hard transmission X-ray microscope (TXM) at the Stanford Synchrotron Radiation Lightsource operating from 5 to 15 keV X-ray energy with 14 to 30 μm2field of view has been used for high-resolution (30–40 nm) imaging and density quantification of mineralized tissue. TXM is uniquely suited for imaging of internal cellular structures and networks in mammalian mineralized tissues using relatively thick (50 μm), untreated samples that preserve tissue micro- and nanostructure. To test this method we performed Zernike phase contrast and absorption contrast imaging of mouse cancellous bone prepared under different conditions ofin vivoloading, fixation, and contrast agents. In addition, the three-dimensional structure was examined using tomography. Individual osteocytic lacunae were observed embedded within trabeculae in cancellous bone. Extensive canalicular networks were evident and included processes with diameters near the 30–40 nm instrument resolution that have not been reported previously. Trabecular density was quantified relative to rod-like crystalline apatite, and rod-like trabecular struts were found to have 51–54% of pure crystal density and plate-like areas had 44–53% of crystal density. The nanometer resolution of TXM enables future studies for visualization and quantification of ultrastructural changes in bone tissue resulting from osteoporosis, dental disease, and other pathologies.
Interference ofPseudomonas aeruginosasignalling and biofilm formation for infection control
Authors: Bjarnsholt Thomas , Tolker-Nielsen Tim , Høiby Niels , Givskov Michael
Published: April 2010

Pseudomonas aeruginosais the best described bacterium with regards to quorum sensing (QS), in vitro biofilm formation and the development of antibiotic tolerance. Biofilms composed ofP. aeruginosaare thought to be the underlying cause of many chronic infections, including those in wounds and in the lungs of patients with cystic fibrosis. In this review, we provide an overview of the molecular mechanisms involved in QS, QS-enabled virulence, biofilm formation and biofilm-enabled antibiotic tolerance. We now have substantial knowledge of the multicellular behaviour ofP. aeruginosain vitro. A major task for the future is to investigate how such in vitro data correlate with the in vivo behaviour ofP. aeruginosa, and how to treat chronic infections of this bacterium in patients.
Long-term evolution of small icy bodies of the Solar System
Authors: Prialnik Dina
Published: April 2010

Detailed evolutionary calculations spanning 4.6 × 109yr are presented for (a) a model representing main-belt comet 133P/Elst-Pizarro, considering different initial mixtures of ices and dust, and (b) a Kuiper Belt object heated by radioactive decay, growing in size from an initial radius of 10 km to a final 250 km.

It is shown that for the main-belt comet only crystalline H2O ice may survive in the interior of the nucleus, and may be found at depths ranging from ~50 to 150 m. Other volatiles will be completely lost. For the large Kuiper Belt object, evaporation and flow of water and vapor gradually remove the water from the core and the final (present) structure is differentiated, with a rocky, highly porous core of 80 km radius. Outside the core, due to refreezing of water vapor, a compact, ice-rich layer forms, a few tens of km thick. The amorphous ice is preserved in an outer layer about 20 km thick.
The surface composition of Enceladus: clues from the Ultraviolet
Authors: Hendrix Amanda R. , Hansen Candice J.
Published: April 2010

The reflectance of Saturn's moon Enceladus has been measured at far ultraviolet (FUV) wavelengths (115–190 nm) by Cassini's UltraViolet Imaging Spectrograph (UVIS). At visible and near infrared (VNIR) wavelengths Enceladus' reflectance spectrum is very bright, consistent with a surface composed primarily of H2O ice. At FUV wavelengths, however, Enceladus is surprisingly dark – darker than would be expected for pure water ice. We find that the low FUV reflectance of Enceladus can be explained by the presence of a small amount of NH3and a small amount of a tholin in addition to H2O ice on the surface.
On the Origin of Retrograde Orbit Satellites around Saturn and Jupiter
Authors: Ma Yuehua , Zheng Jiaqing , Shen Xiaohai
Published: April 2010

Many Retrograde Orbit Satellites around Jupiter and Saturn have been found recently. Most of them are small with irregular shapes. They are farther from the planet than regular satellites. Their orbits have big eccetricities.

We tested their dynamical origin and found:

1.

The small bodies can be captured by normal satellites and form retrograde orbits. But these orbits are not stable. Sooner or later, they would escape from planetary region or fall down into the planets.

2.

Another way is that they have formed by collisions just after regular moons formed. We studied the mechanism and obtained good results.
Modeling the effects of a faint dust coma on asteroid spectra
Authors: Carvano Jorge Márcio , Lorenz-Martins Silvia
Published: April 2010

In this work we use a simple model to study the influence of a faint dust coma on asteroid spectra, in an effort to reproduce the unusual spectral behavior seen on the asteroid (5201) Ferraz-Mello and other objects.
Imaging hydraulic fractures in a geothermal reservoir
Authors: Julian Bruce R. , Foulger Gillian R. , Monastero Francis C. , Bjornstad Steven
Published: April 2010

An injection experiment at the Coso geothermal field in eastern California in March 2005 caused a swarm of microearthquakes that was recorded by a local network of three‐component digital seismometers. High‐resolution relative hypocenter locations propagated upward and northward on a 700 × 600 m plane striking N 20°E and dipping 75° to the WNW. This plane is a pre‐existing fault, whose surface projection coincides with an active scarp. The earthquakes have similar non‐double‐couple mechanisms that involve volume increases, and the fault plane bisects their dilatational fields, implying a process dominated by tensile failure. The source types require the additional involvement of subsidiary shear faulting, however. Events before and after the swarm have variable orientations and volume changes of both signs. Similar tensile‐shear failure is observed in some natural microearthquake swarms, for example at Long Valley caldera, California. Its occurrence under low fluid pressure may imply a heterogeneous stress field or the induction of thermal stresses by introduction of cold fluid.
Specular reflection on Titan: Liquids in Kraken Mare
Authors: Stephan Katrin , Jaumann Ralf , Brown Robert H. , Soderblom Jason M. , Soderblom Laurence A. , Barnes Jason W. , Sotin Christophe , Griffith Caitlin A. , Kirk Randolph L. , Baines Kevin H. , Buratti Bonnie J. , Clark Roger N. , Lytle Dyer M. , Nelson Robert M. , Nicholson Phillip D.
Published: April 2010

After more than 50 close flybys of Titan by the Cassini spacecraft, it has become evident that features similar in morphology to terrestrial lakes and seas exist in Titan's polar regions. As Titan progresses into northern spring, the much more numerous and larger lakes and seas in the north‐polar region suggested by Cassini RADAR data, are becoming directly illuminated for the first time since the arrival of the Cassini spacecraft. This allows the Cassini optical instruments to search for specular reflections to provide further confirmation that liquids are present in these evident lakes. On July 8, 2009 Cassini VIMS detected a specular reflection in the north‐polar region of Titan associated with Kraken Mare, one of Titan's large, presumed seas, indicating the lake's surface is smooth and free of scatterers with respect to the wavelength of 5 μm, where VIMS detected the specular signal, strongly suggesting it is liquid.
On large‐scale wave structure and equatorial spread F without a post‐sunset rise of the F layer
Authors: Tsunoda Roland T. , Bubenik David M. , Thampi Smitha V. , Yamamoto Mamoru
Published: April 2010

Large‐scale wave structure (LSWS) and the plasma structure, referred to as equatorial spread F (ESF), are shown, for the first time, to develop on a night, when the post‐sunset rise (PSSR) of the F layer was absent. Using ionograms from two nearby locations, together with measurements of total electron content, LSWS and ESF are also shown to coexist in regions that are bounded geographically. These results point to the undeniable importance of LSWS (as well as the PSSR) in the day‐to‐day variability in occurrence of ESF, and a need to use of a two‐dimensional description of the electrodynamics.
Elves and associated electron density changes due to cloud‐to‐ground and in‐cloud lightning discharges
Authors: Marshall R. A. , Inan U. S. , Glukhov V. S.
Published: April 2010

A 3‐D finite difference time domain model is used to simulate the lightning electromagnetic pulse (EMP) and its interaction with the lower ionosphere. Results agree with the frequently observed, doughnut‐shaped optical signature of elves but show that the structure exhibits asymmetry due to the presence of Earth's ambient magnetic field. Furthermore, in‐cloud (horizontal) lightning channels produce observable optical emissions without the doughnut shape and, in fact, produce a much stronger optical output for the same channel current. Electron density perturbations associated with elves are also calculated, with contributions from attachment and ionization. Results presented as a function of parameters such as magnetic field direction, dipole current orientation, altitude and amplitude, and ambient ionospheric density profile demonstrate the highly nonlinear nature of the EMP‐ionosphere interaction. Ionospheric effects of a sequence of in‐cloud discharges are calculated, simulating a burst of in‐cloud lightning activity and resulting in large density changes in the overlying ionosphere.
Inner core rotation and its variability from nonparametric modeling
Authors: Lindner Daniela , Song Xiaodong , Ma Ping , Christensen Doug H.
Published: April 2010

We present a new approach for studying the inner core rotation and its variability by separating the underlying structure from its time evolution. This is achieved by fitting a large set of existing seismic BC‐DF traveltime data with a smoothing spline analysis, which is implemented in the statistics package R. This method allows us to separate the time‐independent mantle contribution from the time‐dependent core contribution without any a priori constraints and to also estimate the error of the fit. We add our newly acquired seismic data from the PASSCAL experiment ARCTIC in northern Alaska to PKP differential traveltime measurements previously obtained from South Sandwich Islands earthquakes and recorded at College (COL) and the Alaskan Seismic Network. This nearly doubles the number of measurements to a total of 1165 and increases the data coverage of the inner core structure and our time coverage (to about 55 years). The large number of measurements allows us to use the standard statistical method of bootstrapping to derive the rotation rate and thus to further separate the core structure from its time evolution. This approach has been successfully tested with synthetic data sets that feature both a nonlinear structure and variable rotation rates, while sharing the same earthquakes and stations geometry as our real data. Applying this method to the real data yields an average rotation rate of 0.39° ± 0.090.22° yr−1 (at 68% confidence level). Our results also suggest a nonzero acceleration of the inner core with an apparent change in the rotation rate from 0.24° to 0.56° yr−1 within the last 55 years. The minimum torque acting on the inner core is estimated 1.19 × 1016 N m, which could result from the imbalance of the electromagnetic and gravitational torques.
International VLBI Service for Geodesy and Astrometry: Earth orientation parameter combination methodology and quality of the combined products
Authors: Böckmann S. , Artz T. , Nothnagel A. , Tesmer V.
Published: April 2010

The analysis coordinator of the International VLBI Service for Geodesy and Astrometry (IVS) regularly disseminates the official IVS products of Earth orientation parameters (EOPs). For 2 years now, these parameters have been produced by combining datum‐free normal equations of up to six IVS analysis centers. In this paper we document the combination methodology, discuss critical issues, and report on the quality of the products. The agreement of the very long baseline interferometry results with the International Global Navigation Satellite Systems (GNSS) Service GPS EOPs is of the order of 18 μs for length of day and 100 μas (microarc seconds) and 300 μas/d for the polar motion components and their rates, respectively.