bluuebunny/crossref_metadata_2025 huggingface dataset:
Diversity, abundance and seasonality of birds in a Caribbean pine plantation and native broad-leaved forest at Trinidad, West Indies
Authors: Hayes Floyd E. , Samad Ishmaelangelo
Published: May 2010

Monoculture plantations of exotic Caribbean pinePinus caribaeahave been planted extensively in many tropical countries, but little is known about the bird communities inhabiting them. From October 1995 to September 1996, we compared bird populations in a 37-ha stand of mature Caribbean pine forest (planted in 1972) with an adjacent, similar-sized stand of native broad-leaved forest at Mount Saint Benedict, Trinidad, West Indies. Ten censuses, each including 10 fixed-radius point counts (25 m radius, 10 minutes duration), were conducted simultaneously during different months of the year in each habitat. Both species richness and species diversity were significantly lower in the pine forest, but the overall abundance of individual birds did not differ between the two forests. Seasonal variation in bird populations was more pronounced in the pine forest, where fewer birds (and presumably food resources) were present during the dry season. The pine forest bird community was dominated by forest edge specialists and the native forest by forest interior specialists at both the individual and species levels. At the individual level, nectarivores, aerial foragers and understorey foragers were proportionately more common in the pine forest; insectivores and canopy foragers were more common in the native forest. At the species level, more aerial foragers occurred in the pine forest and more understorey foragers in the native forest. The diversity of bird communities in pine plantations may be promoted by increasing habitat heterogeneity.
PRIVATE OWNERSHIP
Authors: Dorfman Avihay
Published: May 2010

The most powerful response to growing skepticism about the intelligibility of the idea of private ownership has been cast in terms of an owner's rights to the exclusive use of an object. In these pages, I argue that this response suffers from three basic deficiencies—rather than merely explanatory gaps—that render it unable to overcome the specter of skepticism. These deficiencies reflect a shared want of attention to the normative relationship that ownership engenders between owners and nonowners. In place of the right to exclusive use, I set out to develop an account of private ownership that seeks to defeat skepticism concerning this idea. The proposed account insists that the idea of private ownership picks out a special authority relation between an owner and a nonowner involving the normative standing of the latter in relation to an object owned by the former. I further demonstrate the important place of this idea in shaping the contours of normative disagreements about the point of ownership rights and responsibilities.
DIVISION III: COMMITTEE ON SMALL BODY NOMENCLATURE
Authors: Ticha Jana , Marsden Brian G. , Meech Karen , Green Daniel , Schulz Rita , A'Hearn Michael F. , Bowell Edward L. G. , Fernandez Julio , Kilmartin Pam , Nakano Syuichi , Noll Keith , Schmadel Lutz , Shor Viktor , Williams Gareth , Yeomans Donald K. , Zhu Jin
Published: May 2010

The CSBN meeting held in Rio de Janeiro on August 11 was attended by just six members, including Pam Kilmartin as the acting chair, and several visitors. Since there was not a quorum of members, it was not possible to make any decisions. But there was a good discussion on many topics, from which several points emerged that should be more fully discussed by the whole committee during the next few months:
DIVISION III WORKING GROUP on PLANETARY SYSTEM NOMENCLATURE
Authors: Schulz Rita , Aksnes K. , Blue J. , Bowell E. , Burba G. A. , Consolmagno G. , Courtin R. , Lopes R. , Marov M. Ya. , Marsden B. G. , Robinson M. S. , Shevchenko V. V. , Smith B. A.
Published: May 2010

The meeting was attended by 5 members of the WG (E. Bowell, G. Consolmagno, R. Courtain, R. Lopez, R. Schulz) one Task Group member (J. Watanabe), and several guests from the CSBN and CBAT. It was decided at the beginning of the meeting that the attending members of the WGPSN would discuss matters, provide their opinion or vote, and then ask the other 8 formal members to do the same via email. As a consequence the following discussed items have been agreed by majority vote of the WG members.
INTER-DIVISION IV-V WORKING GROUP on Ap and Related Stars
Authors: Cunha Margarida S. , Weiss Werner , Dworetsky Mike , Kochukhov Oleg , Kupka Friedrich , Leblanc Francis , Monier Richard , Paunzen Ernst , Piskunov Nikolai , Shibahashi Hiromoto , Smalley Barry , Ziznovsky Jozef
Published: May 2010

The business meeting started at 11h00, in the presence of 18 members, with a brief summary of the activities and achievements of the Working group during the triennium 2006-2009.
COMMISSION 27: VARIABLE STARS
Authors: Kawaler Steven D. , Handler Gerald , Aerts Conny , Bedding Tim , Catelan Márcio , Cunha Margarida , Eyer Laurent , Jeffery Simon , Martinez Peter , Oláh Katalin , Pollard Karen , Somasundaram Seetha
Published: May 2010

The meeting started at 14h00. The president welcomed the participants to the business meeting of C27, and acknowledged the members of the Organizing Committee. Special thanks were expressed to the outgoing members: Conny Aerts, Peter Martinez, and Seetha Somasundaram.
Are health problems systemic? Politics of access and choice under Beveridge and Bismarck systems
Authors: Or Zeynep , Cases Chantal , Lisac Melanie , Vrangbæk Karsten , Winblad Ulrika , Bevan Gwyn
Published: May 2010

Industrialised countries face similar challenges for improving the performance of their health system. Nevertheless, the nature and intensity of the reforms required are largely determined by each country’s basic social security model. Most reforms in Beveridge-type systems have sought to increase choice and reduce waiting times while those in major Bismarck-type systems have focused on cost control by constraining the choice of providers. This paper looks at the main differences in performance of five countries and reviews their recent reform experience, focusing on three questions: Are there systematic differences in performance of Beveridge and Bismarck-type systems? What are the key parameters of healthcare system, which underlie these differences? Have recent reforms been effective?

Our results do not suggest that one system-type performs consistently better than the other. In part, this may be explained by the heterogeneity in organisational design and governance both within and across these systems. Insufficient attention to those structural differences may explain the limited success of a number of recent reforms. Thus, while countries may share similar problems in terms of improving healthcare performance, adopting a ‘copy-and-paste’ approach to healthcare reform is likely to be ineffective.
Schizophrenieforme Symptomatik bei Chorea minor
Authors: Vloet Jennifer A. , Herpertz-Dahlmann Beate , Hahn Freya , Häusler Martin , Holtkamp Kristian
Published: May 2010

Die Chorea minor (Sydenham), die häufigste erworbene Ursache für Bewegungsstörungen im Kindesalter, ist gekennzeichnet durch unwillkürliche und abrupte Bewegungsmuster. Bei einem Teil der Patienten treten zusätzlich neuropsychologische Dysfunktionen und psychiatrische Störungsbilder wie Angst-, Zwangs-, und Tic-Störungen auf. Psychotische Symptome wurden dabei bisher nur selten beschrieben (n = 4, davon zwei Fallberichte sowie eine prospektive und eine retrospektive Studie). Wir berichten von einer 12-jährigen Patientin mit akuter paranoid-halluzinatorischer Symptomatik und choreatiformer Bewegungsstörung. Die Kombination der im Hinblick auf die paranoid-halluzinatorische Symptomatik wirksamen antipsychotischen Therapie mit hochdosiertem Prednisolon verbesserte die weiterbestehende Negativ-Symptomatik und führte zu einer vollständigen Remission der Bewegungsstörung. Nach Reduktion der Steroide traten eine Verschlechterung der Negativ-Symptomatik und ein Rezidiv der Bewegungsstörung ein. Ursächlich für die Schizophrenie wird eine Funktionsstörung des Corpus Striatum vermutet, welche sekundär das Arbeitsgedächtnis und den für kognitive Flexibilität bedeutsamen präfrontalen Kortex beeinträchtigt. Als Ursache der Chorea minor gilt eine postinfektiöse autoimmun-mediierte Störung der Basalganglienfunktion, ausgelöst durch einen vorausgegangenen Streptokokken-Infekt. Der Morbus Huntington und der Morbus Wilson sind Bewegungsstörungen, die auf einer Basalgangliendysfunktion beruhen und zudem häufig mit psychotischen Symptomen assoziiert sind. Ähnlich könnte die Kombination aus psychotischer und choreatiformer Symptomatik unserer Patientin auf einer Basalgangliendysfunktion beruhen. Die Negativ-Symptomatik wäre durch eine sekundäre Störung präfrontal kortikaler Strukturen erklärbar.
Psychiatrische Störungen und neurologische Komorbiditäten bei Kindern und Jugendlichen mit Intelligenzminderung
Authors: Wriedt Elke , Wiberg Anja , Sakar Vehbi , Noterdaeme Michele
Published: May 2010

Einleitung: Der vorliegende Beitrag gibt einen Überblick über psychiatrische Störungen, komorbide somatische Erkrankungen, psychosoziale Belastungsfaktoren sowie psychosoziale Anpassung von Kindern und Jugendlichen mit Intelligenzminderung, die durch den Mobilen kinder- und jugendpsychiatrischen Dienst des Heckscher Klinikums behandelt wurden. Methodik: Die Befunde von 257 psychiatrisch auffälligen Kindern und Jugendlichen mit Intelligenzminderung wurden ausgewertet. Ergebnisse: In den betreuten ambulanten und teilstationären Einrichtungen waren ca. 14 %, im Wohnheimbereich über 40 % der Kinder und Jugendlichen mit intellektueller Behinderung psychiatrisch auffällig. Der Schwerpunkt der gestellten Diagnosen lag bei den Anpassungsstörungen, hyperkinetischen Störungen, Störungen des Sozialverhaltens, emotionalen Störungen sowie tiefgreifenden Entwicklungsstörungen. Die untersuchten Patienten, insbesondere mit schwerer Intelligenzminderung, wiesen ein großes Spektrum an zusätzlichen körperlichen Erkrankungen und Behinderungen auf und waren in ihrer psychosozialen Anpassung schwer beeinträchtigt. Schlussfolgerungen: Anhand der vorliegenden Zahlen lässt sich der große Bedarf nach psychiatrischer Versorgung in den Einrichtungen für Kinder und Jugendliche mit Intelligenzminderung belegen. Die Entwicklung integrativer, multidimensionaler und multiprofessioneller Behandlungsmodelle, die die besonderen Bedürfnisse der jungen Menschen mit Intelligenzminderung bzw. Mehrfachbehinderung berücksichtigen, ist dringend erforderlich.
Soziale Informationsverarbeitung bei körperlich und relational aggressiven Vorschulkindern
Authors: Helmsen Johanna , Petermann Franz
Published: May 2010

Fragestellung: Es wurde untersucht, ob körperlich und relational aggressive Kinder Defizite in der sozialen Informationsverarbeitung aufweisen. Methodik: 193 Kindern im Vorschulalter (mittleres Alter: 55 Monate) wurden hypothetische soziale Situationen vorgegeben, um Defizite der sozialen Informationsverarbeitung zu erheben (feindselige Absichtsattribution, Generierung aggressiver Reaktionen, positive Aggressionsbewertung, aggressive Reaktionsentscheidung). Ergebnisse: Körperlich aggressive Kinder interpretierten häufiger feindselige Absichten, generierten mehr aggressive Reaktionen, sie entschieden sich häufiger für aggressives Verhalten und wiesen mehr Gesamtdefizite in der sozialen Informationsverarbeitung auf als Kinder ohne körperliche Aggression. Relational aggressive Kinder hingegen zeigten keine Probleme in der sozialen Informationsverarbeitung. Schlussfolgerungen: Das soziale Informationsverarbeitungsmodell trägt nicht zur Erklärung relational aggressiven Verhaltens bei. Zur Prävention oder Verringerung körperlicher Aggression sollte bereits im Vorschulalter die soziale Informationsverarbeitung gefördert werden.
Spontaneous EEG Oscillations in Children, Adolescents, and Adults
Authors: Barry Robert J. , Clarke Adam R.
Published: May 2010

Data are presented on EEG activity in typically developing controls, focusing on the traditional delta, theta, alpha, and beta bands through childhood, with some extensions into adolescence and adults. Both eyes-closed and eyes-open resting state data are discussed. These reflections of typical development provide a framework for illustrating EEG differences in people with attention deficit/hyperactivity disorder (AD/HD), and its main diagnostic types, from children to adults. Comorbidity effects in the EEG of children with AD/HD, particularly comorbid reading disabilities and conduct disorders, are also described. Some recent explorations of the links between arousal/activation and EEG activity may contribute to our understanding of the functional nature of brain oscillations in this context. Other aspects of oscillatory brain activity, coherence and event-related potentials, are also briefly discussed within this framework.
Flanker-Task in Children
Authors: Albrecht Björn , Heinrich Hartmut , Brandeis Daniel , Uebel Henrik , Yordanova Juliana , Kolev Vasi , Rothenberger Aribert , Banaschewski Tobias
Published: May 2010

Response processing may comprise multiple systems working in parallel at different functional levels of performance monitoring. In time-frequency decompositions of response-locked event-related potentials from adults, a subprocess operating in the delta frequency band was interpreted as an index of cognitive error monitoring, distinguishable from a process with theta frequency probably related to motor control. However, it remains unclear whether such subprocesses can also be distinguished in children. In the current study, error processing was assessed in 22 normal boys aged 8 to 15 years using an Erikson Flanker task. Performance data revealed the expected indices of conflicting task demands, such as increased reaction times and error rates. A clear error-negativity was found in the response-locked event-related potentials after incompatible stimuli, and correct responses show a slow negative deflection immediately preceding the button-press, which is absent in errors. Time-frequency decompositions disclosed that a subprocess in the lower delta band preceding correct responses may reflect a more general action monitoring process sensitive to conflicting task demands that, moreover, may prevent one from making an error if it is active early enough. Processes in the delta and theta bands are modulated specifically by errors and may index motor-related monitoring in children. Moreover, these processes occurred considerably earlier for correct responses compared to errors, suggesting that their timing reflects some performance capacity. These considerations may help to clarify response processing in tasks with conflicting demands.
The Attenuation of Very Low Frequency Brain Oscillations in Transitions from a Rest State to Active Attention
Authors: Helps Suzannah K. , Broyd Samantha J. , James Christopher J. , Karl Anke , Sonuga-Barke Edmund J. S.
Published: May 2010

Background: The default mode interference hypothesis ( Sonuga-Barke & Castellanos, 2007 ) predicts (1) the attenuation of very low frequency oscillations (VLFO; e.g., .05 Hz) in brain activity within the default mode network during the transition from rest to task, and (2) that failures to attenuate in this way will lead to an increased likelihood of periodic attention lapses that are synchronized to the VLFO pattern. Here, we tested these predictions using DC-EEG recordings within and outside of a previously identified network of electrode locations hypothesized to reflect DMN activity (i.e., S3 network; Helps et al., 2008 ). Method: 24 young adults (mean age 22.3 years; 8 male), sampled to include a wide range of ADHD symptoms, took part in a study of rest to task transitions. Two conditions were compared: 5 min of rest (eyes open) and a 10-min simple 2-choice RT task with a relatively high sampling rate (ISI 1 s). DC-EEG was recorded during both conditions, and the low-frequency spectrum was decomposed and measures of the power within specific bands extracted. Results: Shift from rest to task led to an attenuation of VLFO activity within the S3 network which was inversely associated with ADHD symptoms. RT during task also showed a VLFO signature. During task there was a small but significant degree of synchronization between EEG and RT in the VLFO band. Attenuators showed a lower degree of synchrony than nonattenuators. Discussion: The results provide some initial EEG-based support for the default mode interference hypothesis and suggest that failure to attenuate VLFO in the S3 network is associated with higher synchrony between low-frequency brain activity and RT fluctuations during a simple RT task. Although significant, the effects were small and future research should employ tasks with a higher sampling rate to increase the possibility of extracting robust and stable signals.
Event-Related Oscillations and Cognitive Processes in Children
Authors: Heinrich Hartmut , Kolev Vasil , Rothenberger Aribert , Yordanova Juliana
Published: May 2010

Event-related EEG modulations, which are phase-locked to perceptual, cognitive, and motor processes, are often studied by means of event-related potentials (ERPs), although event-related oscillatory responses in different EEG frequency bands allow a more refined analysis, closer to brain physiology. This article introduces the basics of time-frequency methods, which are typically applied for the analysis of event-related oscillations, focusing on adaptive procedures (e.g., wavelet networks). The potential of these methods is illustrated. Findings about event-related oscillations (gamma responses, theta responses) in children performing an auditory selective attention task are reviewed. Both the neuronal substrates of gamma (30–70 Hz) networks and the ability to synchronize these networks in relation to task-specific processes are available in children and adolescents from 9 to 16 years of age. Developmental changes in the task reactivity of synchronized gamma oscillations may provide evidence for a transition in cognitive processing strategies emerging at the age of 12–13 years. Event-related theta (3–7.5 Hz) activity is enhanced in two latency ranges. The early event-related theta response occurring 0–200 ms after a stimulus may be associated with representations of relevant target features in working memory. The late fronto-central theta response (200 – 450 ms) could be related to the processing of task-irrelevant information. In summary, event-related oscillations can be analyzed using time-frequency methods like wavelet networks. This approach should be used intensively to study neurocognitive development in children.
Spatial Tests, Familiarity with the Surroundings, and Spatial Activity Experience
Authors: Neidhardt Eva , Popp Michael
Published: May 2010

Spatial orientation as the ability to know the bearing to the origin of a walked path was investigated in two studies with ca. 140 preschool and primary school children who walked paths of about 1 km beginning at the familiar kindergarten or in a completely unknown territory. Path difficulty and familiarity with the surroundings influenced correctness of pointing. Spatial ability measured by test performance and spatial activity experience, i.e., children’s reports about unsupervised walks, effected pointing accuracy as well. The data emphasize that spatial activity experience may be an important factor for spatial orientation beyond kindergarten age.
Effects of Age and Sex in Mental Rotation and Spatial Learning from Virtual Environments
Authors: Schoenfeld Robby , Lehmann Wolfgang , Leplow Bernd
Published: May 2010

The study examined the age and sex effects in spatial learning and mental rotation in 58 adults. We developed two new spatial learning tasks using virtual reality (VR): a navigation task and a pointing task. The results show that younger adults outperformed older adults in both virtual tasks but not in mental rotation. Males outperformed females in the navigation task and mental rotation. We conclude that age generally drives differences in spatial learning, and that sex drives differences in spatial abilities, which were especially related to ability in navigating through virtual environments.
The Neural Network of Spatial Cognition and its Modulation by Biological and Environmental Factors
Authors: Jordan Kirsten , Wüstenberg Torsten
Published: May 2010

Using functional magnetic resonance imaging (fMRI), we investigated the question, if the neural spatial cognition network is modulated by biological (Sex) and environmental factors (Experience, Spatial Component). Sex and Experience modulate response selection and motor imagery. Both Spatial Component and Experience are strongly related to brain activity in visual areas. The interaction between Spatial Component and Experience revealed that high spatial experience and significant better performance in the mental rotation task are related to task-specific neural changes. We conclude that brain areas involved in perceptual and motor processes are associated with the investigated factors Sex, Spatial Component, and Experience. The neural activity in core regions of the spatial cognition network seems to be associated with specific performance changes. Further studies should examine whether these results are specific to our spatial tasks or can be generalized to other cognitive tasks.
Does Children’s Left Hemisphere Lateralization During Mental Rotation Depend Upon the Stimulus Material?
Authors: Lange Léonie F. , Heil Martin , Jansen Petra
Published: May 2010

Recent publications suggest that there is a developmental-based change of lateralization of brain activity during mental rotation from left to bilateral. But it is an open question whether this left hemisphere activation could also be observed with stimuli other than characters. To test this, behavioral data and event-related potentials (ERPs) were measured in 28 children, 28 juveniles, and 28 adults during a mental rotation task with animal drawings. The results showed that reaction times (RTs) and error rates decreased with the increasing age of the participants. Furthermore, RTs and error rates increased with increasing angular disparity. An unlateralized ERP amplitude modulation at parietal electrodes as a function of angular disparity was present in all age groups. These results contrast former studies revealing a left lateralization in children when characters were used as stimuli for mental rotation. Left hemisphere activation is therefore not a general developmental trend; rather, it is suggested that it might be a correlate of written language acquisition.
The Solution Strategy as an Indicator of the Developmental Stage of Preschool Children’s Mental-Rotation Ability
Authors: Quaiser-Pohl Claudia , Rohe Anna M. , Amberger Tobias
Published: May 2010

The solution strategies of preschool children solving mental-rotation tasks were analyzed in two studies. In the first study n = 111 preschool children had to demonstrate their solution strategy in the Picture Rotation Test (PRT) items by thinking aloud; seven different strategies were identified. In the second study these strategies were confirmed by latent class analysis (LCA) with the PRT data of n = 565 preschool children. In addition, a close relationship was found between the solution strategy and children’s age. Results point to a stage model for the development of mental-rotation ability as measured by the PRT, going from inappropriate strategies like guessing or comparing details, to semiappropriate approaches like choosing the stimulus with the smallest angle discrepancy, to a holistic or analytic strategy. A latent transition analysis (LTA) revealed that the ability to mentally rotate objects can be influenced by training in the preschool age.
Gender Differences in the Mental Rotations Test Are Partly Explained by Response Format
Authors: Glück Judith , Fabrizii Claudia
Published: May 2010

Gender differences in the Mental Rotations Test ( Vandenberg & Kuse, 1978 ) are larger than in virtually all other spatial tests and have been highly robust over decades. Several possible explanations for this phenomenon have been proposed. This research tests the hypothesis that the gender differences are partly due to the response format of the MRT (two out of four responses correct in each item). This format, in combination with the high time pressure of the MRT, may be particularly conducive to the performance of highly confident (i.e., frequently male) participants who use “quick-and-dirty” response strategies. In study of 288 students, a new MRT version was used in which a variable number of 0 to 4 alternatives per item were correct. Gender differences were significantly smaller than in the standard MRT. In particular, the performance of highly confident male participants was markedly lower than in the standard MRT.
Choosing Compassionate Strategies to End a Relationship
Authors: Sprecher Susan , Zimmerman Corinne , Abrahams Erin M.
Published: May 2010

Past research has established that people choose from a variety of different strategies to end relationships. In Study 1, 47 disengagement strategies were rated on degree of compassion toward the partner. In Study 2, we examined people’s choice of breakup strategies (in a hypothetical breakup) at varying levels of compassion as a function of compassionate love for their partner and the manipulated reason for the breakup. Compassionate strategies were chosen more frequently when the reason for the breakup was external or dyadic, as compared to partner betrayal. Higher scores on the Compassionate Love Scale ( Sprecher & Fehr, 2005 ) were associated with the greater likelihood of choosing compassionate strategies. An interaction between gender, compassionate love score, and reason for the breakup was also found.
Guilt and Shame Through Recipients’ Eyes
Authors: Giner-Sorolla Roger , Kamau Caroline W. , Castano Emanuele
Published: May 2010

Previous research has found that people collectively wronged by an outgroup take insult when its representative offers compensation, and that an expression of shame but not guilt can lower such insult. This experiment showed a moderating factor: strength of outgroup blame. Black community members were participants, presented with an apology for discriminatory searches of Blacks by the police. The effects – that shame but not guilt reduces insult from compensation – were replicated only among those who strongly blamed outgroup entities. As before, these effects emerged only on insult rather than satisfaction measures, and only when compensation was offered. When blamed by the public, an official body should therefore consider how much its apology conveys shame rather than guilt.
Multiple rapid polarity swings during the Matuyama‐Brunhes transition from two high‐resolution loess‐paleosol records
Authors: Yang Tianshui , Hyodo Masayuki , Yang Zhenyu , Li Huidi , Maeda Makoto
Published: May 2010

Two high‐resolution magnetic records of the Matuyama‐Brunhes (M‐B) transition have been obtained from Xifeng and Baoji loess‐paleosol sequences in the Chinese Loess Plateau. The results of stepwise thermal and alternating field (AF) demagnetizations confirm that both treatments are effective in isolating characteristic remanent magnetization (ChRM) from specimens of loess‐paleosol sediments which suffer from weak pedogenesis, and that AF demagnetization clearly fails to isolate ChRM from specimens of paleosol sediments which have undergone strong pedogenesis. On the basis of virtual geomagnetic pole latitudes crossing the virtual geomagnetic equator, the M‐B transition involves at least 15 rapid polarity swings. Rock magnetic experiments and anisotropy of low‐field magnetic susceptibility show that high‐frequency polarity swings during the M‐B transition cannot be attributed to rock‐magnetic and/or sedimentary causes. Extrapolating a constant accumulation rate between the Jaramillo‐Matuyama and M‐B boundary ages, the M‐B transition interval of both the Xifeng and Baoji sections is estimated to have a duration of more than 10 kyr. Durations of each short polarity interval are estimated to range from about 0.3 to 5.6 kyr. Our new results, combined with previous paleomagnetic observations from lavas and marine sediments, suggest that multiple rapid polarity swings occurred during the M‐B transition.
Dynamical heating of the polar summer mesopause induced by solar proton events
Authors: Becker E. , von Savigny C.
Published: May 2010

The observed heating of the polar summer mesopause during and after a solar proton event (SPE) is interpreted as a large‐scale dynamical response to the temporary diabatic cooling in the lower mesosphere above the summer pole that results from the temporary ozone depletion during an SPE. Our method is based on time slice sensitivity experiments performed with a mechanistic general circulation model. The model response shows that according to the gradient wind balance, the polar lower mesospheric cooling induces an anomalous eastward wind component. As a result, the drag exerted by eastward propagating gravity waves (GWs) shifts to lower altitudes in tandem with a balancing downward shift of the residual circulation. Around the extratropical summer mesopause, this is accompanied by an anomalous large‐scale dynamic heating which qualitatively explains the positive temperature response in this region. A quantitative inspection of the zonal momentum and sensible heat budgets reveals that the GW drag response is partly compensated by a downshift of planetary Rossby waves and that about two thirds of the anomalous large‐scale dynamic heating around the mesopause is balanced by changes of the direct thermal effects due to GWs, diffusion, and dissipation.
Comment on “Influence of the Southern Oscillation on tropospheric temperature” by J. D. McLean, C. R. de Freitas, and R. M. Carter
Authors: Foster G. , Annan J. D. , Jones P. D. , Mann M. E. , Mullan B. , Renwick J. , Salinger J. , Schmidt G. A. , Trenberth K. E.
Published: May 2010

McLean et al. (2009) (henceforth MFC09) claim that the El Niño–Southern Oscillation (ENSO), as represented by the Southern Oscillation Index (SOI), accounts for as much as 72% of the global tropospheric temperature anomaly and an even higher 81% of this anomaly in the tropics. They conclude that the SOI is a “dominant and consistent influence on mean global temperatures,” “and perhaps recent trends in global temperatures.” However, their analysis is inappropriate in a number of ways and overstates the influence of ENSO on the climate system. This comment first briefly reviews what is understood about the influence of ENSO on global temperatures and then shows that the analysis of MFC09 greatly overestimates the correlation between temperature anomalies and the SOI by inflating the power in the 2–6 year time window while filtering out variability on longer and shorter time scales. The suggestion in their conclusions that ENSO may be a major contributor to recent trends in global temperature is not supported by their analysis or any physical theory presented in their paper, especially as the analysis method itself eliminates the influence of trends on the purported correlations.
Developing empirical lightning cessation forecast guidance for the Cape Canaveral Air Force Station and Kennedy Space Center
Authors: Stano Geoffrey T. , Fuelberg Henry E. , Roeder William P.
Published: May 2010

This research addresses the 45th Weather Squadron's (45WS) need for improved guidance regarding lightning cessation at Cape Canaveral Air Force Station and Kennedy Space Center (KSC). KSC's Lightning Detection and Ranging (LDAR) network was the primary observational tool to investigate both cloud‐to‐ground and intracloud lightning. Five statistical and empirical schemes were created from LDAR, sounding, and radar parameters derived from 116 storms. Four of the five schemes were unsuitable for operational use since lightning advisories would be canceled prematurely, leading to safety risks to personnel. These include a correlation and regression tree analysis, three variants of multiple linear regression, event time trending, and the time delay between the greatest height of the maximum dBZ value to the last flash. These schemes failed to adequately forecast the maximum interval, the greatest time between any two flashes in the storm. The majority of storms had a maximum interval less than 10 min, which biased the schemes toward small values. Success was achieved with the percentile method (PM) by separating the maximum interval into percentiles for the 100 dependent storms. PM provides additional confidence to the 45WS forecasters, and a modified version was incorporated into their forecast procedures starting in the summer of 2008. This inclusion has resulted in ∼5–10 min time savings. Last, an experimental regression variant scheme using non‐real‐time predictors produced precise results but prematurely ended advisories. This precision suggests that obtaining these parameters in real time may provide useful added information to the PM scheme.
Winds at the Phoenix landing site
Authors: Holstein‐Rathlou C. , Gunnlaugsson H. P. , Merrison J. P. , Bean K. M. , Cantor B. A. , Davis J. A. , Davy R. , Drake N. B. , Ellehoj M. D. , Goetz W. , Hviid S. F. , Lange C. F. , Larsen S. E. , Lemmon M. T. , Madsen M. B. , Malin M. , Moores J. E. , Nørnberg P. , Smith P. , Tamppari L. K. , Taylor P. A.
Published: May 2010

Wind speeds and directions were measured on the Phoenix Lander by a mechanical anemometer, the so‐called Telltale wind indicator. Analysis of images of the instrument taken with the onboard imager allowed for evaluation of wind speeds and directions. Daily characteristics of the wind data are highly turbulent behavior during midday due to daytime turbulence with more stable conditions during nighttime. From Ls ∼77°–123° winds were generally ∼4 m s−1 from the east, with 360° rotation during midday. From Ls ∼123°–148° daytime wind speeds increased to an average of 6–10 m s−1 and were generally from the west. The highest wind speed recorded was 16 m s−1 seen on Ls ∼147°. Estimates of the surface roughness height are calculated from the smearing of the Kapton part of the Telltale during image exposure due to a 3 Hz turbulence and nighttime wind variability. These estimates yield 6 ± 3 mm and 5 ± 3 mm, respectively. The Telltale wind data are used to suggest that Heimdal crater is a source of nighttime temperature fluctuations. Deviations between temperatures measured at various heights are explained as being due to winds passing over the Phoenix Lander. Events concerning sample delivery and frost formation are described and discussed. Two different mechanisms of dust lifting affecting the Phoenix site are proposed based on observations made with Mars Color Imager on Mars Reconnaissance Orbiter and the Telltale. The first is related to evaporation of the seasonal CO2 ice and is observed up to Ls ∼95°. These events are not associated with increased wind speeds. The second mechanism is observed after Ls ∼111° and is related to the passing of weather systems characterized by condensate clouds in orbital images and higher wind speeds as measured with the Telltale.
Patterns of spatial and temporal variability in streamflow records in south central Chile in the period 1952–2003
Authors: Rubio‐Álvarez Eduardo , McPhee James
Published: May 2010

In this work we study the time series of annual and seasonal streamflow for 44 rivers in southern Chile, spanning the ecoregion between 34°S and 45°S for the 1952–2003 period. We analyze spatial variability using a clustering process to define regional streamflow averages. We find two main regions, divided approximately by parallel 37.5°S. The analysis includes application of the multitaper (MTM) and maximum entropy (MEM) methods to find periodicities or interannual and decadal cycles. Singular spectral analysis (SSA) is applied in order to augment the signal‐to‐noise ratio. Significant correlation with climatic indexes was found at different spatial and temporal scales, with El Niño–Southern Oscillation (ENSO) influence being stronger at the northern subregion, and notably the Antarctic Oscillation (AAO) and the Pacific Decadal Oscillation (PDO) showing strong correlation with summer flows in the southern subregion. Also, we found significant decreasing trends affecting a region between 37.5°S and 40°S. These are coherent with decreasing trends observed in precipitation in the area, and also with a decreasing trend observed in the Southern Oscillation Index (SOI). These findings provide, for the first time, a comprehensive view of the streamflow variability in a sensitive ecoregion in South America. We expect that these results will inform decision making in a context of increasing water demands for diverse uses as well as contribute to the general understanding of climatic patterns of variability in the Pacific Rim.
A closed‐form equation for effective stress in unsaturated soil
Authors: Lu Ning , Godt Jonathan W. , Wu David T.
Published: May 2010

We propose that the recently conceptualized suction stress characteristic curve represents the effective stress for the shear strength behavior of unsaturated soil. Mechanically, suction stress is the interparticle stress called tensile stress. The working hypothesis is that the change in the energy of soil water from its free water state is mostly consumed in suction stress. We demonstrate that the suction stress lies well within the framework of continuum mechanics where free energy is the basis for any thermodynamic formulation. Available experimental data on soil water characteristic curves and suction stress characteristic curves are used to test the hypothesis, thus validating a closed‐form equation for effective stress in unsaturated soil. The proposed closed‐form equation is intrinsically related to the soil water characteristic curve by two pore parameters: the air entry pressure and pore size spectrum number. Both semiquantitative and quantitative validations show that the proposed closed‐form equation well represents effective stress for a variety of earth materials ranging from sands to clays. Of important practical implications are (1) the elimination of the need for any new shear strength criterion for unsaturated soil, (2) the elimination of the need for determining the Bishop's effective stress parameter χ because the new form of effective stress is solely a function of soil suction, and (3) the ready extension of all classical soil mechanics work on limit equilibrium analysis to unsaturated soil conditions.
Science, Space, and Shuttles: An Interview With Astronaut and AGU Member Piers Sellers
Authors: Kumar Mohi
Published: May 2010

On 14 May, NASA is scheduled to launch what will likely be the final mission for space shuttle Atlantis. This mission will deliver cargo and science payloads—including the Russian‐built Mini Research Module (MRM 1)—to the International Space Station (ISS).

On board the shuttle will be Piers Sellers, an AGU member. Born in 1955 in Crowborough, United Kingdom, Sellers completed his doctorate in biometeorology at UK's Leeds University in 1981. He became an AGU Fellow in 1996 for research on how the Earth's biosphere and atmosphere interact; that same year, he was selected as an astronaut candidate. He has since logged more than 559 hours in space on two shuttle missions. In the course of those missions, he spent almost 41 hours on six space walks.

During his current mission, Sellers will be operating a robotic arm nearly 60 feet long from inside a viewing cupola on the ISS. This arm will move components around the outside of the station and, with the help of astronauts on space walks, will attach MRM 1 to ISS. On 3 May, Eos science writer/editor Mohi Kumar, along with journalists from other news agencies, got to chat with Sellers about his current mission and his experiences as an astronaut. An edited transcript follows.
Parameters that control lithospheric‐scale thermal localization on terrestrial planets
Authors: Crameri Fabio , Kaus Boris J. P.
Published: May 2010

Shear‐heating induced localization has been suggested as a potentially important mechanism for breaking the lithosphere. Yet, the physical parameters that control the onset of this instability remain unclear. We therefore performed systematic 2‐D simulations of visco‐elasto‐plastic lithospheric deformation in which we addressed the effects of various parameters and we found that a sharp transition exists between localizing and non‐localizing regimes. In a next step we develop a semi‐analytical model that combines scaling laws with a 1‐D lithospheric deformation model. We show that the 1‐D model successfully predicts the occurrence of shear localization in 2‐D models, if the thickness of the plastically deforming part of the (lower) lithosphere is employed as characteristic length‐scale. An application of the 1‐D model to the terrestrial planets shows that this type of shear‐localization is expected to occur most readily on Earth.
Can internal processes sustain reversals of the ocean upper circulation? The Ionian Sea example
Authors: Gačić M. , Borzelli G. L. Eusebi , Civitarese G. , Cardin V. , Yari S.
Published: May 2010

In 1997 an inversion in the Ionian upper‐layer circulation was documented and ascribed to a massive inflow of Aegean dense waters associated with the Eastern Mediterranean Transient (EMT) and not to the wind‐stress (Borzelli et al., 2009). Here we generalize the concept hypothesizing that such inversions are possible even in the absence of the Aegean influence. Indeed, salinity and density data collected in the Southern Adriatic, the main source of the Eastern Mediterranean deep water, show decadal variations coherent with changes in the sea level height in the northern Ionian. Scaling considerations suggest that the redistribution of Ionian water masses, resulting from changes in the thermohaline properties of waters entering the basin, can sustain inversions of the upper‐layer circulation. Therefore, we propose a feedback mechanism (named the Adriatic‐Ionian Bimodal Oscillating System – BiOS) between variations in the thermohaline properties of waters formed in the Southern Adriatic and the Ionian circulation.
Apparent/spurious multifractality of absolute increments sampled from truncated fractional Gaussian/Lévy noise
Authors: Neuman Shlomo P.
Published: May 2010

Many earth and environmental variables appear to scale as multifractals with spatial or temporal increments having exceedance probability tails decaying as powers of −α where 1 < α ≤ 2. The literature considers multifractal scaling to be associated with multiplicative random fields or processes. Elsewhere the author has demonstrated theoretically that square increments, sampled across a finite domain from one or several realizations of additive fractional Gaussian noise (fGn), behave as if the field was multifractal when in fact it is monofractal self‐affine; square increments sampled from additive fractional Lévy noise (fLn) with 1 < α < 2 exhibit spurious multifractality. This brief letter demonstrates the same numerically for random absolute increments. The results have broad implications vis‐à‐vis the scaling of variables considered in the literature to be multifractal, raising the possibility that some if not all may in fact represent truncated monofractal phenomena.
Ubiquitous cyanobacterial podoviruses in the global oceans unveiled through viral DNA polymerase gene sequences
Authors: Huang Sijun , Wilhelm Steven W , Jiao Nianzhi , Chen Feng
Published: May 2010

As a major cyanophage group, cyanobacterial podoviruses are important in regulating the biomass and population structure of picocyanobacteria in the ocean. However, little is known about their biogeography in the open ocean. This study represents the first survey of the biodiversity of cyanopodoviruses in the global oceans based on the viral encoded DNA polymerase (pol) gene. A total of 303 DNA pol sequences were amplified by PCR from 10 virus communities collected in the Atlantic and Pacific oceans and the South China Sea. At least five subclusters of cyanopodoviruses were identified in these samples, and one subcluster (subcluster VIII) was found in all sampling sites and comprised approximately 50% of total sequences. The diversity index based on the DNA pol gene sequences recovered through PCR suggests that cyanopodoviruses are less diverse in these oceanic samples than in a previously studied estuarine environment. Although diverse podoviruses were present in the global ocean, each sample was dominated by one major group of cyanopodoviruses. No clear biogeographic patterns were observed using statistical analysis. A metagenomic analysis based on the Global Ocean Sampling database indicates that other types of cyanopodovirus-like DNA pol sequences were present in the global ocean. Together, our study results suggest that cyanopodoviruses are widely distributed in the ocean but their community composition varies with local environments.
Transcriptomic analysis of a marine bacterial community enriched with dimethylsulfoniopropionate
Authors: Vila-Costa Maria , Rinta-Kanto Johanna M , Sun Shulei , Sharma Shalabh , Poretsky Rachel , Moran Mary Ann
Published: May 2010

Dimethylsulfoniopropionate (DMSP) is an important source of reduced sulfur and carbon for marine microbial communities, as well as the precursor of the climate-active gas dimethylsulfide (DMS). In this study, we used metatranscriptomic sequencing to analyze gene expression profiles of a bacterial assemblage from surface waters at the Bermuda Atlantic Time-series Study (BATS) station with and without a short-term enrichment of DMSP (25 nm for 30 min). An average of 303 143 reads were obtained per treatment using 454 pyrosequencing technology, of which 51% were potential protein-encoding sequences. Transcripts from Gammaproteobacteria and Bacteroidetes increased in relative abundance on DMSP addition, yet there was little change in the contribution of two bacterioplankton groups whose cultured members harbor known DMSP degradation genes, Roseobacter and SAR11. The DMSP addition led to an enrichment of transcripts supporting heterotrophic activity, and a depletion of those encoding light-related energy generation. Genes for the degradation of C3 compounds were significantly overrepresented after DMSP addition, likely reflecting the metabolism of the C3 component of DMSP. Mapping these transcripts to known biochemical pathways indicated that both acetyl-CoA and succinyl-CoA may be common entry points of this moiety into the tricarboxylic acid cycle. In a short time frame (30 min) in the extremely oligotrophic Sargasso Sea, different gene expression patterns suggest the use of DMSP by a diversity of marine bacterioplankton as both carbon and sulfur sources.