bluuebunny/crossref_metadata_2025 huggingface dataset:
Do Investors See through Mistakes in Reported Earnings?
Authors: Bardos Katsiaryna Salavei , Golec Joseph , Harding John P.
Published: June 2011

This study investigates whether investors see through materially misstated earnings, and whether they anticipate earnings restatements. For firms that restate at least one annual report, we find that investors are misled by mistakes in reported earnings at the time of initial earnings announcements. Investors react positively to the component of the favorable earnings surprise that will subsequently be restated, and they attach the same valuation to it as to the true earnings surprise. We also find that investors anticipate the subsequent downward restatements and start marking stock prices down several months before a restatement announcement, so that the full impact of a restatement is about three times as large as the restatement announcement effect. Indeed, we show that investors punish restating firms because the stock price gains that shareholders enjoy when firms initially announce overstated earnings are more than reversed by the time of the restatement announcement.
Effect of primary, cross-over, zigzag neopharyngoplasty on acoustic characteristics of alaryngeal, tracheoesophageal voice
Authors: Albirmawy O A
Published: June 2011

Objective:

To evaluate the effect of primary, cross-over, zigzag neopharyngeal construction on tracheoesophageal voice, compared with pharyngoesophageal myotomy, following total laryngectomy with partial pharyngectomy.

Study design:

Prospective clinical trial.

Setting:

Otolaryngology department, Tanta University Hospital (tertiary referral centre), Egypt.

Patients and methods:

Over five years, 30 patients underwent total laryngectomy with partial pharyngectomy to manage stage III or IV laryngeal cancer, followed by primary tracheoesophageal puncture for voice restoration. For neopharyngeal construction, 15 patients underwent pharyngoesophageal myotomy (group one) and 15 cross-over, zigzag neopharyngoplasty (group two). Acoustic parameters of tracheoesophageal voice were compared.

Results:

Most acoustic parameters were almost equivalent for the two groups, although significant differences were seen for loud intensity, dynamic range, shimmer, loud fundamental frequency, loud jitter, fluency and speaking rate. One post-operative pharyngocutaneous fistula (6.6 per cent) occurred in each group, and resolved with conservative measures.

Conclusion:

The cross-over neopharyngoplasty modification of hypopharyngeal closure may help avoid pharyngoesophageal spasm and assist maintenance of effective voice amplitude, fundamental frequencies, temporal measures and perceptual values.
A Hunsaker Mon-Jet tube trapped in the larynx
Authors: Khan I , Shakeel M , Nagaraja R , Ram B , Thomas A D
Published: June 2011

Objective:

We report a unique complication arising from the use of a Hunsaker Mon-Jet ventilation tube during microlaryngeal surgery, and we briefly review the literature on the use of this tube for jet ventilation.

Method:

A case report on the safe and successful management of a potential airway compromise, and a brief literature review on using the Hunsaker Mon-Jet ventilation tube during microlaryngeal surgery.

Case report:

A 46-year-old woman was scheduled to undergo removal of a vocal cord polyp under general anaesthesia. However, the polyp became stuck in the basket of the Hunsaker tube during intubation. The polyp and the Hunsaker tube were removed safely after a microlaryngeal tube was passed beyond the vocal cords. To our knowledge, this complication has not previously been reported.

Conclusion:

This case highlights the potential risk of laryngeal growths, especially vocal cord polyps, becoming trapped in the Hunsaker tube during intubation. Both the anaesthetist and the operating surgeon should be aware of this possible complication and, more importantly, how to deal with such a problem.
TESTING FOR THE MARKOV PROPERTY IN TIME SERIES
Authors: Chen Bin , Hong Yongmiao
Published: June 2011

The Markov property is a fundamental property in time series analysis and is often assumed in economic and financial modeling. We develop a new test for the Markov property using the conditional characteristic function embedded in a frequency domain approach, which checks the implication of the Markov property in every conditional moment (if it exists) and over many lags. The proposed test is applicable to both univariate and multivariate time series with discrete or continuous distributions. Simulation studies show that with the use of a smoothed nonparametric transition density-based bootstrap procedure, the proposed test has reasonable sizes and all-around power against several popular non-Markov alternatives in finite samples. We apply the test to a number of financial time series and find some evidence against the Markov property.
Positional Accuracy of Assisted GPS Data from High-Sensitivity GPS-enabled Mobile Phones
Authors: Zandbergen Paul A. , Barbeau Sean J.
Published: June 2011

Utilizing both Assisted GPS (A-GPS) techniques and new high-sensitivity embedded GPS hardware, mobile phones are now able to achieve positioning in harsh environments such as urban canyons and indoor locations where older embedded GPS chips could not. This paper presents an empirical analysis of the positional accuracy of location data gathered using a high-sensitivity GPS-enabled mobile phone. The performance of the mobile phone is compared to that of regular recreational grade GPS receivers. Availability of valid GPS position fixes on the mobile phones tested was consistently close to 100% both outdoors and indoors. During static outdoor testing, positions provided by the mobile phones revealed a median horizontal error of between 5·0 and 8·5 m, substantially larger than those for regular autonomous GPS units by a factor of 2 to 3. Horizontal errors during static indoor testing were larger compared to outdoors, but the difference in accuracy between mobile phones and regular GPS receivers was reduced. Despite the modest performance of A-GPS on mobile phones, testing under various conditions revealed that very large errors are not very common. The maximum horizontal error during outdoor testing never exceeded 30 metres and during indoor testing never exceeded 100 metres. Combined with the relatively consistent availability of valid GPS position fixes under varying conditions, the current study has confirmed the reliability of A-GPS on mobiles phones as a source of location information for a range of different LBS applications.
Strategies of Young Pigeons during ‘Map’ Learning
Authors: Schiffner Ingo , Pavkovic Tina , Siegmund Bettina , Wiltschko Roswitha
Published: June 2011

The routes of young, inexperienced pigeons released at four sites up to 13·5 km from the loft were recorded with GPS-based tracking devices. The routes were found to differ from those of old, experienced pigeons in several aspects: (1) Although being oriented when departing, young birds show more scatter and larger deviations from the home direction, but usually restrict their flights to a semicircle. (2) They apparently ignore prominent landmarks near the loft that are clearly visible. (3) Their tracks are typically more complex, consisting of a number of distinctive phases where the young birds head in different directions, which results in significantly longer routes, often exceeding the direct home distances more than four times. (4) At the same time, young birds seldom venture further away from the release site than the direct distance to home. Their behaviour can be interpreted as exploration to obtain new information on the distribution of navigational factors to be included in their still rudimentary navigational ‘map’. At the same time, their flights seem to include elements of safety, like anchoring the flights around the release site and a sense of distance, which help to reduce the chance of getting lost.
Air Traffic Control Separation Minima: Part 1 – The Current Stasis
Authors: Brooker Peter
Published: June 2011

Current strategic plans for air traffic management (ATM) envisage a transition from radar control to a trajectory-based system. The future ATM concepts are very different in a great number of aspects from the present system. The focus here is on the design of safe systems, in particular the appropriate air traffic control (ATC) separation minima. This Part 1 sketches the historical origins of ATC separation minima and then analyses the safety thinking behind current minima and the issues involved in risk modelling. Why have the critical minima largely remained unchanged for several decades – stasis? Part 2 then addresses key safety issues in the transition to the new ATM concept.

‘Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.’ Archimedes.
Spatial epidemiology of suspected clinical leptospirosis in Sri Lanka
Authors: ROBERTSON C. , NELSON T. A. , STEPHEN C.
Published: June 2011

Leptospirosis is one of the most widespread zoonoses in the world. A large outbreak of suspected human leptospirosis began in Sri Lanka during 2008. This study investigated spatial variables associated with suspected leptospirosis risk during endemic and outbreak periods. Data were obtained for monthly numbers of reported cases of suspected clinical leptospirosis for 2005–2009 for all of Sri Lanka. Space–time scan statistics were combined with regression modelling to test associations during endemic and outbreak periods. The cross-correlation function was used to test association between rainfall and leptospirosis at four locations. During the endemic period (2005–2007), leptospirosis risk was positively associated with shorter average distance to rivers and with higher percentage of agriculture made up of farms <0·20 hectares. Temporal correlation analysis of suspected leptospirosis cases and rainfall revealed a 2-month lag in rainfall-case association during the baseline period. Outbreak locations in 2008 were characterized by shorter distance to rivers and higher population density. The analysis suggests the possibility of household transmission in densely populated semi-urban villages as a defining characteristic of the outbreak. The role of rainfall in the outbreak remains to be investigated, although analysis here suggests a more complex relationship than simple correlation.
Überzeugungen über das Erscheinungsbild
Authors: Grocholewski Anja , Tuschen-Caffier Brunna , Margraf Jürgen , Heinrichs Nina
Published: June 2011

Zusammenfassung. Theoretischer Hintergrund: Das Appearance Schemas Inventory-Revised (ASI-R) ist ein Selbstbeurteilungsinstrument, das die Überzeugungen im Sinne der selbstevaluativen Salienz bzw. die motivationale Salienz bezüglich des eigenen Erscheinungsbildes misst. Das ASI-R hat sich an einer US-amerikanischen Stichprobe (N = 603) als valide und reliabel erwiesen. Fragestellung: Ist das Konstrukt auch in der deutschen Version valide und reliabel? Methode: Stichproben aus unterschiedlichen Populationen (Studierende, Patientinnen mit der Diagnose einer Essstörung, Personen mit medizinisch-kosmetischem Behandlungswunsch, Bevölkerungsstichprobe, Psychotherapiestichprobe) bekamen das ASI-R und weitere Instrumente zur Feststellung von Reliabilität und konvergenter und divergenter Validität vorgelegt, Gesamtstichprobe N = 1.256). Ergebnisse: Die Reliabilität des Instruments liegt bei Cronbachs α = .72–.89. Die konvergente Validität bewegt sich zwischen .51–.68 (EDE), und –.07––.33 (RSE), die divergente Validität für die Gesamtskala zwischen .28 (ADS-K), .35 (GSI SCL-90-R) und .44 (GSI BSI). Das ASI-R ist diskriminant valide in Bezug auf Geschlecht und spezifische psychische Störungen. Faktorenanalysen bestätigen die Konstruktvalidität in einer studentischen Stichprobe und einer Stichprobe von Personen mit kosmetisch-medizinischem Behandlungswunsch. Schlussfolgerung: Das ASI-R ist geeignet, Überzeugungen über das Erscheinungsbild reliabel und valide zu erfassen. Die Unterteilung in selbstevaluative und motivationale Aspekte scheint nur für Studierende, Personen mit körperdysmorphen Störungen und Personen mit einem Wunsch nach kosmetisch-medizinischer Behandlung relevant zu sein.
Discontinuous Galerkin methods with transient hp adaptation
Authors: Schnepp S. , Weiland T.
Published: June 2011

A discontinuous Galerkin method (DGM) for Maxwell’s equations in time domain and dedicated techniques for adaptive mesh refinement are presented. Since the DGM is a finite element–type method, it offers two refinement mechanisms: the manipulation of the local mesh step size (h adaptation) and the adaptation of the local approximation order (p adaptation). For both cases, a new approximation is obtained by means of projections between finite element spaces. The projection operators introduced are optimal with respect to the projection error. A reliable estimator for the local smoothness of the solution is presented, which forms the basis for the hp decision, i.e., the choice of the type of adaptation to be performed. The stability and efficiency of the adaptive method are demonstrated, allowing for performing transient mesh refinement, i.e., the continuous adaptation of the mesh according to the current situation.
Using time‐lapse gravity for groundwater model calibration: An application to alluvial aquifer storage
Authors: Christiansen L. , Binning P. J. , Rosbjerg D. , Andersen O. B. , Bauer‐Gottwein P.
Published: June 2011

The estimation of hydrological model parameters by calibration to field data is a critical step in the modeling process. However, calibration often fails because of parameter correlation. Here it is shown that time‐lapse gravity data can be combined with hydraulic head data in a coupled hydrogeophysical inversion to decrease parameter correlation in groundwater models. This is demonstrated for a model of riverbank infiltration where combined inversion successfully constrains hydraulic conductivity and specific yield in both an analytical and a numerical groundwater model. A sensitivity study shows that time‐lapse gravity data are especially useful to constrain specific yield. Furthermore, we demonstrate that evapotranspiration, and riverbed conductance are better constrained by coupled inversion to gravity and head data than to head data alone. When estimating the four parameters simultaneously, the six correlation coefficients were reduced from unity when only head data were employed to significantly lower values when gravity and head data were combined. Our analysis reveals that the estimated parameter values are not very sensitive to the choice of weighting between head and gravity data over a large interval of relative weights.
Discharge estimation from H‐ADCP measurements in a tidal river subject to sidewall effects and a mobile bed
Authors: Sassi M. G. , Hoitink A. J. F. , Vermeulen B. , Hidayat
Published: June 2011

Horizontal acoustic Doppler current profilers (H‐ADCPs) can be employed to estimate river discharge based on water level measurements and flow velocity array data across a river transect. A new method is presented that accounts for the dip in velocity near the water surface, which is caused by sidewall effects that decrease with the width to depth ratio of a channel. A boundary layer model is introduced to convert single‐depth velocity data from the H‐ADCP to specific discharge. The parameters of the model include the local roughness length and a dip correction factor, which accounts for the sidewall effects. A regression model is employed to translate specific discharge to total discharge. The method was tested in the River Mahakam, representing a large river of complex bathymetry, where part of the flow is intrinsically three‐dimensional and discharge rates exceed 8000 m3 s−1. Results from five moving boat ADCP campaigns covering separate semidiurnal tidal cycles are presented, three of which are used for calibration purposes, whereas the remaining two served for validation of the method. The dip correction factor showed a significant correlation with distance to the wall and bears a strong relation to secondary currents. The sidewall effects appeared to remain relatively constant throughout the tidal cycles under study. Bed roughness length is estimated at periods of maximum velocity, showing more variation at subtidal than at intratidal time scales. Intratidal variations were particularly obvious during bidirectional flow conditions, which occurred only during conditions of low river discharge. The new method was shown to outperform the widely used index velocity method by systematically reducing the relative error in the discharge estimates.
Modulation of soluble and particulate antigen transport in afferent lymph by monophosphoryl lipid A
Authors: de Veer Michael , Kemp Joanna , Chatelier Josh , Elhay Martin J , Meeusen Els NT
Published: June 2011

Vaccine adjuvants stimulate the innate immune system and determine the outcome of the immune response induced. A better understanding of their action is therefore crucial to the development of new and safer vaccines. Monophosphoryl lipid A (MPL), a ‘detoxified’ version of lipolysaccharide, is a promising new adjuvant component in human vaccines. The present study uses an ovine lymphatic cannulation model to study cell recruitment and antigen transport from the injection site into the afferent lymph, and how this is modulated by co‐injection with MPL. Compared with saline, MPL injections caused only minor variations in lymph flow and no difference in cell number migrating into the lymph. MPL did, however, cause a significantly increased recruitment of neutrophils and monocytes, but not dendritic cells (DC) into the lymph for the first 12 h. Soluble ovalbumin (OVA) antigen flowed freely into the lymph over a 24‐h period and was slightly reduced at 6–9 h in the MPL‐injected sites. OVA‐coated fluorescent 1‐μ beads were initially transported predominantly by neutrophils and, from 24 to 72 h, by DC. MPL induced an increased and more sustained transport of beads by neutrophils and monocytes although it did not increase the phagocytic capacity of these cells. In contrast to aluminium adjuvant, MPL did not increase bead transport by DC at the later time point. These studies provide important new insights in the in vivo action of different adjuvants and the initial events that set up an immune response after vaccination.
Classifications of Vocalic Segments From Articulatory Kinematics: Healthy Controls and Speakers With Dysarthria
Authors: Yunusova Yana , Weismer Gary G. , Lindstrom Mary J.
Published: June 2011

Purpose

In this study, the authors classified vocalic segments produced by control speakers (C) and speakers with dysarthria due to amyotrophic lateral sclerosis (ALS) or Parkinson’s disease (PD); classification was based on movement measures. The researchers asked the following questions: (a) Can vowels be classified on the basis of selected measures of articulatory motions? and (b) Can classification models that are constructed from control productions classify vowels produced by speakers with dysarthria that is related to ALS and PD?

Method

Nineteen C, 7 PD, and 8 ALS speakers participated in this study. The severity of dysarthria varied across individuals and between the 2 disorder groups. The stimuli were 6 vowels produced in 10 words embedded into sentences read at a comfortable reading rate. Movement data were collected using the x-ray microbeam. Movement measures included distances traveled, durations, and average speeds of vowel-related movement strokes. Vowels and words were classified by linear discriminant analysis with measures of articulatory motion as input variables.

Results

The study showed that vocalic segments could be classified using articulatory movement characteristics with up to 80% accuracy. The classification accuracy of the movement-based models depended largely on the number of articulators involved and, to a lesser extent, on the movement measure (e.g., distance, duration, speed). Classification of PD vowels was similar to that of the C group, suggesting a simple scaling of gestures as an explanation of the movement deficit in this disease. Classification performance for ALS vowels appeared to be different from that of C and PD productions.

Conclusion

Classification of vowels was possible on the basis of their articulatory motions. ALS vowels appeared categorically different from those of C and PD speakers.
Enhancing Speech Discrimination Through Stimulus Repetition
Authors: Holt Rachael Frush
Published: June 2011

Purpose

To evaluate the effects of sequential and alternating repetition on speech-sound discrimination.

Method

Typically hearing adults' discrimination of 3 pairs of speech-sound contrasts was assessed at 3 signal-to-noise ratios using the change/no-change procedure. On change trials, the standard and comparison stimuli differ; on no-change trials, they are identical. Listeners were presented with 5 repetition conditions: 2 and 4 sequential repetitions of the standard followed by sequential repetitions of the comparison; 2 and 4 alternating presentations of the standard and comparison; and 1 repetition of the standard and comparison.

Results

Both sequential and alternating repetition improved discrimination of the fricative and liquid contrasts, but neither was clearly superior to the other across the conditions.

Conclusions

The results support previous findings that increasing the number of fricative and liquid stimulus presentations improves discriminability and extends the findings to natural speech stimuli. Further, the effect of repetition is robust: Both sequential and alternating repetitions improve speech-sound discrimination, and few differences emerge between the two types of stimulus repetitions. The results have implications for evaluating the strength of the internal representation of speech stimuli in clinical populations believed to have a core deficit in phonological encoding, such as children with hearing loss.
Sustained Attention in Children With Primary Language Impairment: A Meta-Analysis
Authors: Ebert Kerry Danahy , Kohnert Kathryn
Published: June 2011

Purpose

This study provides a meta-analysis of the difference between children with primary or specific language impairment (LI) and their typically developing peers on tasks of sustained attention. The meta-analysis seeks to determine whether children with LI demonstrate subclinical deficits in sustained attention and, if so, under what conditions.

Method

Articles that reported empirical data from the performance of children with LI, in comparison to typically developing peers, on a task assessing sustained attention were considered for inclusion. Twenty-eight effect sizes were included in the meta-analysis. Two moderator analyses addressed the effects of stimulus modality and attention-deficit/hypereactivity disorder exclusion. In addition, reaction time outcomes and the effects of task variables were summarized qualitatively.

Results

The meta-analysis supports the existence of sustained attention deficits in children with LI in both auditory and visual modalities, as demonstrated by reduced accuracy compared with typically developing peers. Larger effect sizes are found in tasks that use auditory–linguistic stimuli than in studies that use visual stimuli.

Conclusions

Future research should consider the role that sustained attention weaknesses play in LI as well as the implications for clinical and research assessment tasks. Methodological recommendations are summarized.
First-principles investigation of the stability of MN and CrMN precipitates under coherency strains in α-Fe (M = V, Nb, Ta)
Authors: Fors Dan H. R. , Wahnström Göran
Published: June 2011

We perform a systematic ab initio study of the interface energetics of thin coherent rocksalt (nacl) structured MN and tetragonal CrMN films in bcc Fe (M = V, Nb, Ta), motivated by the vital role of MN and CrMN precipitates for the long-term creep resistance in 9%–12%Cr steels. The similarities and differences in the work of separations and the elastic costs for the coherency strains are identified, and the possibility for formation of coherent films are discussed. Our findings provide valuable information of the interface energetics, which in continuation can be combined with thermodynamical modeling to obtain a better understanding of the initial nucleation stage of the MN and CrMN precipitates, and their influence on the long-term microstructural evolution in 9%–12%Cr steels.
Bi-stability in turbulent, rotating spherical Couette flow
Authors: Zimmerman Daniel S. , Triana Santiago Andrés , Lathrop D. P.
Published: June 2011

Flow between concentric spheres of radius ratio η=ri/ro=0.35 is studied in a 3 m diameter experiment. We have measured the torques required to maintain constant boundary speeds as well as localized wall shear stress, velocity, and pressure. At low Ekman number E=2.1×10-7 and modest Rossby number 0.07<Ro<3.4, the resulting flow is highly turbulent with a maximum Reynolds number (Re = Ro/E) exceeding 15 million. Several turbulent flow regimes are evident as Ro is varied for fixed E. We focus our attention on one flow transition, in particular, between Ro = 1.8 and Ro = 2.6, where the flow shows bistable behavior. For Ro within this range, the flow undergoes intermittent transitions between the states observed alone at adjacent Ro outside the switching range. The two states are clearly distinguished in all measured flow quantities, including a striking reduction in torque demanded from the inner sphere by the state lying at higher Ro. The reduced angular momentum transport appears to be associated with the development of a fast zonal circulation near the experiment core. The lower torque state exhibits waves, one of which is similar to an inertial mode known for a full sphere and another which appears to be a strongly advected Rossby-type wave. These results represent a new laboratory example of the overlapping existence of distinct flow states in high Reynolds number flow. Turbulent multiple stability and the resilience of transport barriers associated with zonal flows are important topics in geophysical and astrophysical contexts.
Multi-reference state-universal coupled-cluster approaches to electronically excited states
Authors: Li Xiangzhu , Paldus Josef
Published: June 2011

The multi-reference (MR), general model space (GMS), state-universal (SU), coupled-cluster (CC) method with singles and doubles (GMS-SU-CCSD), as well as its triple-corrected versions GMS-SU-CCSD(T), are employed to assess their ability to describe low-lying excited states of various molecules, with an emphasis on a simultaneous handling of several states of the same symmetry species. A special attention is given to the role of the so-called C-conditions that account for non-vanishing internal cluster amplitudes when relying on an incomplete GMS, as well as to the choice of suitable model spaces and a perturbative account of secondary triples. The ambiguities arising when using large basis sets are also pointed out. To achieve a general assessment of the potential of the GMS-type SU-CC approaches, the vertical excitation energies of several species, including the challenging BN diatomic as well as larger systems, namely formaldehyde, trans-butadiene, formamide, and benzene are considered. These results are compared with those provided by the equation-of-motion EOM-CCSD method and, whenever available, the density functional theory results and experimental data. These comparisons clearly demonstrate the usefulness of GMS-type MR-CC approaches.
Reduction of the virtual space for coupled-cluster excitation energies of large molecules and embedded systems
Authors: Send Robert , Kaila Ville R. I. , Sundholm Dage
Published: June 2011

We investigate how the reduction of the virtual space affects coupled-cluster excitation energies at the approximate singles and doubles coupled-cluster level (CC2). In this reduced-virtual-space (RVS) approach, all virtual orbitals above a certain energy threshold are omitted in the correlation calculation. The effects of the RVS approach are assessed by calculations on the two lowest excitation energies of 11 biochromophores using different sizes of the virtual space. Our set of biochromophores consists of common model systems for the chromophores of the photoactive yellow protein, the green fluorescent protein, and rhodopsin. The RVS calculations show that most of the high-lying virtual orbitals can be neglected without significantly affecting the accuracy of the obtained excitation energies. Omitting all virtual orbitals above \documentclass[12pt]{minimal}\begin{document}$50\,\rm eV$\end{document}50 eV in the correlation calculation introduces errors in the excitation energies that are smaller than \documentclass[12pt]{minimal}\begin{document}$0.1\,\rm eV$\end{document}0.1 eV . By using a RVS energy threshold of \documentclass[12pt]{minimal}\begin{document}$50\,\rm eV$\end{document}50 eV , the CC2 calculations using triple-ζ basis sets (TZVP) on protonated Schiff base retinal are accelerated by a factor of 6. We demonstrate the applicability of the RVS approach by performing CC2/TZVP calculations on the lowest singlet excitation energy of a rhodopsin model consisting of 165 atoms using RVS thresholds between 20 eV and 120 eV. The calculations on the rhodopsin model show that the RVS errors determined in the gas-phase are a very good approximation to the RVS errors in the protein environment. The RVS approach thus renders purely quantum mechanical treatments of chromophores in protein environments feasible and offers an ab initio alternative to quantum mechanics/molecular mechanics separation schemes.
In situ compression study of taper-free metallic glass nanopillars
Authors: Kuzmin O. V. , Pei Y. T. , De Hosson J. T. M.
Published: June 2011

Because tapering leads to inevitable artifacts in the analyses of compression experiments on micrometer sized pillars, in this study taper-free nanosized pillars of Zr-based metallic glass of Zr61.8Cu18Ni10.2Al10 composition with diameter ranging from 600 to 90 nm were fabricated. These pillars were compressed in situ in a transmission electron microscope as a function of pillar diameter. Under compression each pillar of large diameter exhibits predominant inhomogeneous and intermittent plastic flow characterized by shear banding (SB) events. However, pillars around 150 nm in diameter and below show homogeneous deformation during compression without SB.
Rearticulating Caste: The Global Cottonseed Commodity Chain and the Paradox of Smallholder Capitalism in South India
Authors: Ramamurthy Priti
Published: June 2011

Cottonseed is an aspirational crop for smallholders newly incorporated in the global cottonseed commodity chain as own-account cultivators in South India. The labor to produce cottonseeds, which are hybrids, in the field is excessive. Multinational and Indian corporations depend on hybridization to protect their intellectual property rights in branded seeds. As wage rates rise and seed prices do not, the outsourcing of cottonseed production to smallholders is attractive to capital. It is mostly the unpaid, family labor of smallholders which now generates exchange value. While smallholders dream of spectacular gains and some success stories seem to support this, growing cottonseed is a risky business and, at times, the returns to smallholders are so low that the very costs of reproducing family labor are unmet; many go into debt. Yet, smallholders from a formerly untouchable caste, or Dalit, community, who just a short while ago worked as ‘cottonseed children’ for rich farmers are, for the first time, proudly growing cottonseed on ‘their own plots of land’ and ‘laboring for themselves’. To explain this paradox I propose a vernacular calculus of the economic, a noneconomistic grid, for understanding why Dalit smallholders continue this form of production even when they could earn more from wage labor. I argue that the rearticulation of caste in terms of dignity and perceptions of autonomy shape this calculus. I argue further that Dalit smallholders experience the inherent contradictions of capitalism through a ‘structure of feeling’ marked by perplexity. At a time when smallholder contract farming is being suggested as a new development strategy by the World Bank and questioned by its detractors, a vernacular calculus of the economic and affective experiences marked by perplexity may be more widely relevant as generalized characteristics of smallholder capitalism.
The Place of Disarticulations: Global Commodity Production in La Laguna, Mexico
Authors: Bair Jennifer , Werner Marion
Published: June 2011

Studies of the shifting social organization and geography of global garment production have been critical to the development of the commodity chains framework as an important field of study for scholars of political economy in various disciplines. Our paper intervenes in this literature by proposing what we call a ‘disarticulations’ perspective, an approach attentive to historical and spatial processes of accumulation, disinvestment and dispossession that produce the uneven geographies generative of transnational production networks. We make the case for disarticulations as an approach to commodity chains via a case study of a region in north-central Mexico called La Laguna—a celebrated center of export dynamism in the 1990s, following the implementation of the North American Free Trade Agreement (NAFTA), and of rapid decline in the 2000s. Rather than offer a conventional commodity chain analysis of the boom to bust cycle in La Laguna, which would look to the dynamics of the contemporary apparel chain to explain the causes and consequences of La Laguna's NAFTA-era trajectory, we instead follow La Laguna's ‘travels’ through the cotton, textile, and garment industries over 150 years. We show how the recent NAFTA-era boom was premised on this layered history of engagements with the cotton–textile–apparel commodity chain. The disarticulations approach to commodity chains that we develop here foregrounds the processes of dispossession, accumulation and disinvestment through which not only commodity chains, but the uneven geographies that are their conditions of possibility, are reproduced.
Disarticulations and Commodity Chains: Cattle, Coca, and Capital Accumulation along Colombia's Agricultural Frontier
Authors: Hough Phillip A
Published: June 2011

In this paper I take up Jennifer Bair and Marion Werner's call for a commodity-chains analysis which is sensitive to particular places and articulated–disarticulated modes of capital accumulation. The analytical fix is on the Lower and Middle Caguán area of Colombia, explaining how the region became articulated into (and disarticulated from) three distinct commodity chains: a domestic cattle commodity chain (1960s until the late 1970s), a global coca commodity chain (late 1970s to the late 1990s), and a global cattle commodity chain (1990s to the present). In doing so, I find that the articulation of the region into each commodity chain rests critically upon the actions of the state and/or state-like forms of political intervention which are an attempt to rectify the class contradictions associated with the particular modes of capital accumulation associated with that chain. The region's articulation into the domestic ‘hides and meat’ chain rested upon an exclusionary developmental state, its articulation into the global ‘cocaine’ chain rested upon the rise of a proto-state under the leadership of the FARC guerrillas, and its articulation into the global ‘dry milk’ chain has since rested upon a neoliberal state which receives military aid from the US government under the rubric of the War on Drugs and War on Terror initiatives.
Fungi, Trees, People, Nematodes, Beetles, and Weather: Ecologies of Vulnerability and Ecologies of Negotiation in Matsutake Commodity Exchange
Authors: Faier Lieba ,   Matsutake Worlds Research Group
Published: June 2011

The author draws attention to the ways in which commodity chains take shape in the intersections between different natural–cultural ecologies. It is suggested that a focus on the diverse ways that people involved in commodity chains relate to these ecologies reveals not only the links but also the disarticulations through which commodity relations take shape. To develop this perspective, the author focuses on the trade in ‘matsutake,’ a variety of related species of wild mushrooms that are consumed primarily as a gourmet luxury item in Japan. Matsutake have never been successfully cultivated, and during the 1970s and 80s, as a growing market for luxuries in Japan coincided with a decline in domestic production, Japan began importing increasing amounts of them. The author first considers scientific discussions about the contingencies and uncertainties that relationships involving fungi, trees, people, nematodes, beetles, and weather create in different matsutake regions. Discussion then turns to the some of the different ways that matsutake pickers in rural Nagano and matsutake traders in Tokyo make sense of these uncertainties by characterizing matsutake ecologies as, respectively, ecologies of vulnerability and ecologies of negotiation. By attending to the conflicting ways that people make sense of human–nonhuman relations in matsutake exchange, the author demonstrates that commodity chains do not occur through smoothly articulated chains, networks, or circuits: rather, they involve processes in which variously situated ecologies collide across relations of geographical and cultural difference.
Constraints to addressing food insecurity in protracted crises
Authors: Maxwell Daniel , Russo Luca , Alinovi Luca
Published: June 2011

A substantial portion of the world's people have not made adequate progress toward overcoming hunger or achieving sustainable livelihoods. The classic approach to addressing chronic food insecurity has been a strategy of agricultural development, supplemented by humanitarian assistance in the event of a shock or crisis—an approach predicated on assumptions that do not fit the context of protracted crises. This article describes protracted crises and argues that they are sufficiently different to warrant special consideration, but there are unique constraints to engagement in protracted crises. The article explores the constraints promoting sustainable livelihoods in these contexts and proposes elements of an alternative approach. It evaluates the limited evidence available about such an approach and outlines important questions for further research.
Maturation time of new granule cells in the dentate gyrus of adult macaque monkeys exceeds six months
Authors: Kohler Shawn J. , Williams Nancy I. , Stanton Gregory B. , Cameron Judy L. , Greenough William T.
Published: June 2011

We studied two groups of adult macaque monkeys to determine the time course of adult neurogenesis in the dentate gyrus of the hippocampus. In the first group, six adult monkeys (
Macaca mulatta
) received a single injection of the thymidine analog BrdU (75 mg/kg), which is incorporated into replicating DNA and serves as a marker for new cell birth. Brain tissue was collected 48 h, 2 wk, and 6 wk after BrdU injection to examine the initial stages of neurogenesis. Because mature neurons were not evident at 6 wk, we examined tissue collected over a longer time course in a second study. In this study, eight monkeys (
Macaca fascicularis
) who were subjects in a separate exercise study received 10 weekly injections of BrdU (75 mg/kg), and brain tissue was collected at 16 and 28 wk from the first injection. Based on the timing of expression of neuronal cell markers (βIII-tubulin, doublecortin, NeuN), the extent of dendritic arborization, and acquisition of mature cell body morphology, we show that granule cell maturation in the dentate gyrus of a nonhuman primate is protracted over a minimum of a 6-mo time period, more than 6 times longer than in rodents. The lengthened time course for new cell maturation in nonhuman primates may be appropriate for preservation of neural plasticity over their longer life span and is relevant to our understanding of antidepressant and other therapies that have been linked to neurogenesis in humans.
The Era GTPase recognizes the GAUCACCUCC sequence and binds helix 45 near the 3′ end of 16S rRNA
Authors: Tu Chao , Zhou Xiaomei , Tarasov Sergey G. , Tropea Joseph E. , Austin Brian P. , Waugh David S. , Court Donald L. , Ji Xinhua
Published: June 2011

Era, composed of a GTPase domain and a K homology domain, is essential for bacterial cell viability. It is required for the maturation of 16S rRNA and assembly of the 30S ribosomal subunit. We showed previously that the protein recognizes nine nucleotides (

) near the 3′ end of 16S rRNA, and that this recognition stimulates GTP-hydrolyzing activity of Era. In all three kingdoms of life, the

sequence and helix 45 (h45) (nucleotides 1506–1529) are highly conserved. It has been shown that the

to

double mutation severely affects the viability of bacteria. However, whether Era interacts with G1530 and/or h45 and whether such interactions (if any) contribute to the stimulation of Era’s GTPase activity were not known. Here, we report two RNA structures that contain nucleotides 1506–1542 (RNA301), one in complex with Era and GDPNP (GNP), a nonhydrolysable GTP-analogue, and the other in complex with Era, GNP, and the KsgA methyltransferase. The structures show that Era recognizes 10 nucleotides, including G1530, and that Era also binds h45. Moreover, GTPase assay experiments show that G1530 does not stimulate Era’s GTPase activity. Rather, A1531 and A1534 are most important for stimulation and h45 further contributes to the stimulation. Although G1530 does not contribute to the intrinsic GTPase activity of Era, its interaction with Era is important for binding and is essential for the protein to function, leading to the discovery of a new cold-sensitive phenotype of Era.
Hyperinsulinemia leads to uncoupled insulin regulation of the GLUT4 glucose transporter and the FoxO1 transcription factor
Authors: Gonzalez Eva , Flier Emily , Molle Dorothee , Accili Domenico , McGraw Timothy E.
Published: June 2011

Insulin resistance is a component of the metabolic syndrome and Type 2 diabetes. It has been recently shown that in liver insulin resistance is not complete. This so-called selective insulin resistance is characterized by defective insulin inhibition of hepatic glucose output while insulin-induced lipogenesis is maintained. How this occurs and whether uncoupled insulin action develops in other tissues is unknown. Here we show in a model of chronic hyperinsulinemia that adipocytes develop selective insulin resistance in which translocation of the GLUT4 glucose transporter to the cell surface is blunted yet nuclear exclusion of the FoxO1 transcription factor is preserved, rendering uncoupled insulin-controlled carbohydrate and lipid metabolisms. We found that in adipocytes FoxO1 nuclear exclusion has a lower half-maximal insulin dose than GLUT4 translocation, and it is because of this inherent greater sensitivity that control of FoxO1 by physiological insulin concentrations is maintained in adipocytes with compromised insulin signaling. Pharmacological and genetic interventions revealed that insulin regulates GLUT4 and FoxO1 through the PI3-kinase isoform p110α, although FoxO1 showed higher sensitivity to p110α activity than GLUT4. Transient down-regulation and overexpression of Akt isoforms in adipocytes demonstrated that insulin-activated PI3-kinase signals to GLUT4 primarily through Akt2 kinase, whereas Akt1 and Akt2 signal to FoxO1. We propose that the lower threshold of insulin activity for FoxO1’s nuclear exclusion is in part due to its regulation by both Akt isoforms. Identification of uncoupled insulin action in adipocytes suggests this condition might be a general phenomenon of insulin target tissues contributing to insulin resistance’s pathophysiology.
Sequential and spatially restricted interactions of assembly factors with an autotransporter β domain
Authors: Ieva Raffaele , Tian Pu , Peterson Janine H. , Bernstein Harris D.
Published: June 2011

Autotransporters are bacterial virulence factors that consist of an N-terminal extracellular (“passenger”) domain and a C-terminal β barrel domain (“β domain”) that resides in the outer membrane. Here we used an in vivo site-specific photocrosslinking approach to gain insight into the mechanism by which the β domain is integrated into the outer membrane and the relationship between β domain assembly and passenger domain secretion. We found that periplasmic chaperones and specific components of the β barrel assembly machinery (Bam) complex interact with the β domain of the
Escherichia coli
O157:H7 autotransporter extracellular serine protease P (EspP) in a temporally and spatially regulated fashion. Although the chaperone Skp initially interacted with the entire β domain, BamA, BamB, and BamD subsequently interacted with discrete β domain regions. BamB and BamD remained bound to the β domain longer than BamA and therefore appeared to function at a later stage of assembly. Interestingly, we obtained evidence that the completion of β domain assembly is regulated by an intrinsic checkpoint mechanism that requires the completion of passenger domain secretion. In addition to leading to a detailed model of autotransporter biogenesis, our results suggest that the lipoprotein components of the Bam complex play a direct role in the membrane integration of β barrel proteins.
Improving model fidelity and sensitivity for complex systems through empirical information theory
Authors: Majda Andrew J. , Gershgorin Boris
Published: June 2011

In many situations in contemporary science and engineering, the analysis and prediction of crucial phenomena occur often through complex dynamical equations that have significant model errors compared with the true signal in nature. Here, a systematic information theoretic framework is developed to improve model fidelity and sensitivity for complex systems including perturbation formulas and multimodel ensembles that can be utilized to improve both aspects of model error simultaneously. A suite of unambiguous test models is utilized to demonstrate facets of the proposed framework. These results include simple examples of imperfect models with perfect equilibrium statistical fidelity where there are intrinsic natural barriers to improving imperfect model sensitivity. Linear stochastic models with multiple spatiotemporal scales are utilized to demonstrate this information theoretic approach to equilibrium sensitivity, the role of increasing spatial resolution in the information metric for model error, and the ability of imperfect models to capture the true sensitivity. Finally, an instructive statistically nonlinear model with many degrees of freedom, mimicking the observed non-Gaussian statistical behavior of tracers in the atmosphere, with corresponding imperfect eddy-diffusivity parameterization models are utilized here. They demonstrate the important role of additional stochastic forcing of imperfect models in order to systematically improve the information theoretic measures of fidelity and sensitivity developed here.
Light-induced water oxidation at silicon electrodes functionalized with a cobalt oxygen-evolving catalyst
Authors: Pijpers Joep J. H. , Winkler Mark T. , Surendranath Yogesh , Buonassisi Tonio , Nocera Daniel G.
Published: June 2011

Integrating a silicon solar cell with a recently developed cobalt-based water-splitting catalyst (Co-Pi) yields a robust, monolithic, photo-assisted anode for the solar fuels process of water splitting to O
2
at neutral pH. Deposition of the Co-Pi catalyst on the Indium Tin Oxide (ITO)-passivated
p
-side of a
np
-Si junction enables the majority of the voltage generated by the solar cell to be utilized for driving the water-splitting reaction. Operation under neutral pH conditions fosters enhanced stability of the anode as compared to operation under alkaline conditions (pH 14) for which long-term stability is much more problematic. This demonstration of a simple, robust construct for photo-assisted water splitting is an important step towards the development of inexpensive direct solar-to-fuel energy conversion technologies.