bluuebunny/crossref_metadata_2025 huggingface dataset:
A phenomenological challenge to ‘enlightened secularism’
Authors: KIDD IAN JAMES
Published: September 2012

This article challenges Philip Kitcher's recent proposals for an ‘enlightened secularism’. I use William James's theory of the emotions and his related discussion of ‘temperaments’ to argue that religious and naturalistic commitments are grounded in tacit, inarticulate ways that one finds oneself in a world. This indicates that, in many cases, religiosity and naturalism are grounded not in rational and evidential considerations, but in a tacit and implicit sense of reality which is disclosed through phenomenological enquiry. Once the foundational role of these temperaments is appreciated, it emerges that enlightened secularism relies upon a facile conception of the nature of religious belief – one that lessens its chances for success. The article ends with some positive proposals for incorporating phenomenological insights into debates about science, religion, and secularism.
DYNASTIC POLITICS, DEFEAT, DECADENCE AND DINING: CLEOPATRA SELENE ON THE SO-CALLED ‘AFRICA’ DISH FROM THE VILLA DELLA PISANELLA AT BOSCOREALE
Authors: Draycott Jane
Published: September 2012

This article examines the so-called ‘Africa’ dish, part of a treasure trove of silver table-ware discovered in a cistern at the Villa della Pisanella, avilla rusticadestroyed in the eruption of Vesuvius inad79. It proposes a new interpretation of the dish's iconography and argues that the woman in the centre of the emblema is Cleopatra Selene, while the attributes surrounding her reference her parents Cleopatra VII and Marcus Antonius, her brothers Alexander Helios and Ptolemy Philadelphus, her husband Juba II of Mauretania, and their mythological ancestor the demi-god Heracles. Thus the emblema serves as a meditation on the fates of Antony and Cleopatra VII, descendants of Heracles who chose the path of vice, a choice that resulted in their defeat by Octavian at the Battle of Actium. Octavian's virtue, victory and clemency, combined with his guardianship of their children, ensured the subsequent promotion of their daughter Cleopatra Selene as a key figure in his dynastic and political strategy, through her marriage to Juba II and the couple's appointment as client rulers of Mauretania. Also supposedly descended from Heracles, Juba II and Cleopatra Selene chose to follow in their illustrious ancestor's footsteps along the path of virtue. In common with other pieces from the treasure trove, the ‘Africa’ dish alludes to recent historical events and personages, utilizes death as a means of promoting the enjoyment of life, and incorporates popular elements of Greek mythology, all the while offering banqueters an erudite puzzle to solve during the course of their banquet.
APHRODISIAN MARBLE FROM THE GÖKTEPE QUARRIES: THE LITTLE BARBARIANS, ROMAN COPIES FROM THE ATTALID DEDICATION IN ATHENS
Authors: Attanasio Donato , Bruno Matthias , Prochaska Walter , Yavuz Alì Bahadir
Published: September 2012

The marble of seven under-lifesize sculptures of barbarians, now in the archaeological museums of Naples, Venice and the Vatican, commonly considered to be Roman copies of the Pergamene Lesser Dedication in Athens, comes from the Göktepe marble quarries near Aphrodisias, as is shown by isotopic, electron paramagnetic resonance, trace analyses, and of petrographic data. Since this marble was used mostly by Aphrodisian artists, this finding confirms, on the basis of scientific data, previous hypotheses on the origin of the sculptors who manufactured the statues. Reliable discrimination from similar fine-grained Asiatic marbles, such asDocimium, is possible primarily on the basis of the composition of the Göktepe marbles, which have unusually low concentrations of manganese and high concentrations of strontium. Present knowledge of the history of the quarries and the distribution of their marbles seems to rule out the possibility that the sculptures date from the late Republican period and supports the opinion, previously proposed on stylistic grounds, that they were manufactured in Rome by Aphrodisian sculptors probably during the first half of the second centuryad.
SOLDIERS AND EQUESTRIAN RANK IN THE THIRD CENTURYad
Authors: Davenport Caillan
Published: September 2012

This article considers a group of inscriptions, ranging in date from the late second to late third centuriesad, which indicates that low-ranked members of the Roman army gained access to equestrian rank in this period. The inscriptions attest two interrelated phenomena: (1) the promotion of soldiers to posts in themilitiae equestres, a series of officer commands usually held by men from theordo equester; and (2) grants of equestrian status to soldiers' sons, many of whom were only very young. These developments represent a marked departure from the circumstances that prevailed in the early Empire, when equestrian rank could be bestowed only by the emperor on men who possessed a census qualification of 400,000 sesterces. In this article, I propose that successive emperors gave soldiers greater access to themilitiae equestres, and in some cases awarded equestrian rank to their sons, because they recognized the widespread desire for social mobility among the ranks of the army. The widening of access to equestrian rank within the Roman army contributed to the devaluation of this status over the course of the third centuryad.
PANVINIO ANDDESCRIPTIO:RENDITIONS OF HISTORY AND ANTIQUITY IN THE LATE RENAISSANCE
Authors: Stenhouse William
Published: September 2012

This article argues that Onofrio Panvinio's 1571 study of the Roman triumph embodies a central innovation of sixteenth-century classical scholarship, the use of visual reconstructions alongside textual accounts to communicate the details of ancient ceremonies. Panvinio built on the work of predecessors, most notably Pirro Ligorio, to produce a densely-detailed image of the triumphal procession in the style of Roman bas-reliefs, using the evidence of coins, friezes and texts. This illustration can be seen as an alternative historical rendition, rather than as an accompaniment to a textual description of the triumph. More generally, it reveals the creativity of Renaissance antiquarianism, a movement usually seen as devoted to the dry accumulation of evidence about antiquity, not its imaginative interpretation.
OPENING THE FRONTIER: THE GUBBIO–PERUGIA FRONTIER IN THE COURSE OF HISTORY
Authors: Stoddart Simon , Barone Pier Matteo , Bennett Jeremy , Ceccarelli Letizia , Cifani Gabriele , Clackson James , della Giovampaola Irma , Ferrara Carlotta , Fulminante Francesca , Licence Tom , Malone Caroline , Matacchioni Laura , Mullen Alex , Nomi Federico , Pettinelli Elena , Redhouse David , Whitehead Nicholas
Published: September 2012

The frontier between Gubbio (ancient Umbria) and Perugia (ancient Etruria), in the northeast part of the modern region of Umbria, was founded in the late sixth centurybc. The frontier endured in different forms, most notably in the late antique and medieval periods, as well as fleetingly in 1944, and is fossilized today in the local government boundaries. Archaeological, documentary and philological evidence are brought together to investigate different scales of time that vary from millennia to single days in the representation of a frontier that captured a watershed of geological origins. The foundation of the frontier appears to have been a product of the active agency of the Etruscans, who projected new settlements across the Tiber in the course of the sixth centurybc, protected at the outer limit of their territory by the naturally defended farmstead of Col di Marzo. The immediate environs of the ancient abbey of Montelabate have been studied intensively by targeted, systematic and geophysical survey in conjunction with excavation, work that is still in progress. An overview of the development of the frontier is presented here, employing the data currently available.
Arnold Hugh Martin Jones
Authors: Meiggs Russell
Published: September 2012

A. H. M. Jones died from a heart attack on a very rough crossing from Brindisi to Patras; he was on his way to give lectures at the Universities of Thessalonica and Patras. It was a tragically sudden end to a life of intense mental activity. Academically he had fulfilled his greatest ambition; for more than twenty years he had determined to complete a major work of synthesis on the late Roman Empire: the publication in 1964 of The Later Roman Empire 284–602 will still be recognized as a major work by our grandchildren.
Roman Silver in Northumberland
Authors: Haverfield
Published: September 2012

In the first half of the eighteenth century, five pieces of Roman silver plate were discovered in south Northumberland under circumstances which suggest that they belonged to some service or hoard. The proof that they are thus connected together, though very strong, is not absolutely conclusive, and the service or hoard which (if the proof be accepted) they comprised is of no great magnificence; it cannot be set beside the 66 pieces found in 1830 at Bernay near Berthouville, in Normandy, or the 70 pieces found just outside Hildesheim, near Hannover, in 1868, or the 108 pieces dug up at Boscoreale, near Pompeii, in 1895, or the vessels weighing some 2,700 ounces discovered at Trier about 1628, or even the 39 pieces found at Chaourse, near Troyes, in 1883.
Implicit and explicit knowledge in second language acquisition—CORRIGENDUM
Authors: REBUSCHAT PATRICK , WILLIAMS JOHN N.
Published: September 2012

There was an error in German Example (3b) on page 836 and an incorrect reference citation on page 853, both of which are reprinted herein. We regret these errors and any problems they may have caused.
COST-EFFECTIVENESS OF CARDIAC RESYNCHRONIZATION THERAPY: PERSPECTIVE FROM ARGENTINA
Authors: Poggio Rosana , Augustovsky Federico , Caporale Joaquín , Irazola Vilma , Miriuka Santiago
Published: September 2012

Objectives: Cardiac resynchronization therapy (CRT) has recently been shown to reduce both mid-term and long-term mortality in patients with mild heart failure. Although proven effective, it is unclear whether CRT is cost-effective in low and middle-income countries (LMIC). Therefore, we set out to analyze the cost-effectiveness of CRT in Argentina in patients with New York Heart Association (NYHA) functional class (FC) I or II heart failure (HF). We chose to compare patients receiving optimal medical treatment (OMT) and CRT with those patients receiving only OMT.

Methods: We constructed a Markov model with a cohort simulation, and a life-time horizon to assess costs, life-years, and quality-adjusted life-year (QALY) gained as a result of treatment with both CRT and OMT from an Argentine third party payer perspective. We included patients who met the following criteria: left ventricular ejection fraction (LVEF) ≤ 40 percent, sinus rhythm with a QRS ≥ 120 msec, and NYHA FC I-II HF. The results were expressed as cost per life-year and QALY gained in international dollars (ID$) for the year 2009.

Results: For the base case analysis performed, we started at a fixed age of 65. After applying a 3 percent annual discount rate, the incremental cost-effectiveness ratio (ICER) was 38.005 ID$ per year of life gained and 34.185 ID$ per QALY gained.

Conclusions: Long-term treatment with CRT appears to be cost-effective in Argentina compared with patients treated solely with OMT. Similar analysis should be performed to determine if this treatment option is cost-effective in other LMIC.
COST-EFFECTIVENESS OF ORAL TRIPTANS FOR ACUTE MIGRAINE: MIXED TREATMENT COMPARISON
Authors: Asseburg Christian , Peura Piia , Oksanen Tuija , Turunen Juha , Purmonen Timo , Martikainen Janne
Published: September 2012

Background: The cost-effectiveness of triptans in the treatment of migraine has not been assessed since generic sumatriptan entered the Finnish market in 2008.

Methods: Using systematic review and mixed treatment comparison, the effectiveness of triptans was estimated with regard to 2-hour response, 2-hour pain-free, recurrence, and any adverse event, using published clinical data. Direct and indirect costs (2010 EUR, societal perspective) and quality-adjusted life-years (QALYs) were evaluated over one acute migraine attack using a decision-tree model.

Results: The meta-analysis combined data from fifty-six publications. The highest probability of achieving the primary outcome, “sustained pain-free, no adverse event” (SNAE), was estimated for eletriptan 40 mg (20.9 percent). Sumatriptan 100 mg was the treatment with lowest estimated costs (€20.86), and the incremental cost-effectiveness ratio of eletriptan 40 mg compared with sumatriptan 100 mg was €43.65 per SNAE gained (€19,659 per QALY gained).

Conclusion: Depending on the decision-maker's willingness-to-pay threshold, either sumatriptan 100 mg or eletriptan 40 mg is likely to be cost-effective.
Emergence of novelLeptospiraserovars: a need for adjusting vaccination policies for dogs?
Authors: ARENT Z. J. , ANDREWS S. , ADAMAMA-MORAITOU K. , GILMORE C. , PARDALI D. , ELLIS W. A.
Published: September 2012

A total of 855 sera from dogs in Greece were tested for antibodies to strains belonging to the Pomona, Grippotyphosa and Australis serogroups ofLeptospirato assess exposure levels to these serogroups, possible associations with clinical disease and to evaluate whether these findings support the inclusion of additional serovars in dog vaccines. Antibodies were detected in 110 (12·9%) dogs. The highest seroprevalence (4·9%) was to the proposed novel serovar Altodouro belonging to the Pomona serogroup. This serovar also showed a statistically significant association with clinical disease. Serovar Bratislava antibodies were found in 3·4% of sera. Consideration should be given to the inclusion of serovars belonging to the Pomona serogroup and serovar Bratislava in future dog vaccines for the Greek market.
Gaming as extramural English L2 learning and L2 proficiency among young learners
Authors: Sylvén Liss Kerstin , Sundqvist Pia
Published: September 2012

Today, playing digital games is an important part of many young people's everyday lives. Claims have been made that certain games, in particular massively multiplayer online role-playing games (MMORPGs) provide L2 English learners with a linguistically rich and cognitively challenging virtual environment that may be conducive to L2 learning, as learners get ample opportunities for L2 input and scaffolded interaction in the L2. In this paper, we present empirical evidence that L2 English proficiency correlates with the frequency of gaming and types of games played. We base our observation on a study among young L2 English learners (N = 86, aged 11–12, Sweden). Data were collected through a questionnaire, a language diary, and three proficiency tests. The questionnaire provided demographic background information but was also targeted at measuring extramural English habits, i.e., learners’ out-of-school contact with English (cf. Sundqvist, 2009). The diary measured how much time the learners spent on seven predetermined extramural English activities during one week, while the tests measured their achieved L2 proficiency regarding reading and listening comprehension, and vocabulary. Previous research among learners aged 15–16 (Sundqvist, 2009) showed positive correlations between playing digital games and L2 proficiency, in particular with regard to vocabulary, and also identified gender-related differences regarding vocabulary (boys outperformed girls) as well as the frequency of gaming and types of games played. These results were corroborated in the present study. A clear pattern emerged from our data: frequent gamers (≥ 5 hours/week) outperformed moderate gamers who, in turn, outperformed non-gamers. Background variables could not explain the between-group differences. Even though the boys might have been more proficient or apt than the girls a priori and, therefore, chose to engage more in L2 gaming, the findings suggest that playing digital games at an early age can be important for L2 acquisition.
Left ventricular hydatid cyst: an uncommon cause of chest pain in young adults
Authors: Shankarappa Ravindranath K. , Moorthy Nagaraja , Bhat Prabhavathi , Nanjappa Manjunath C.
Published: September 2012

Isolated cardiac involvement in hydatid disease is very rare. We report the case of a young adult male who presented to the emergency department with acute onset of chest pain and was surprisingly detected to have a hydatid cyst in the left ventricular myocardium. The transthoracic echocardiography and cardiac magnetic resonance imaging confirmed the diagnosis. Cardiac hydatid disease should be considered in the differential diagnosis of chest pain in young individuals in the absence of conventional risk factors of atherosclerosis.
TARIFF AND EQUILIBRIUM INDETERMINACY: A GLOBAL ANALYSIS
Authors: Zhang Yan , Chen Yan
Published: September 2012

Zhang [Tariff and Equilibrium Indeterminacy, available at http://mpra.ub.uni-muenchen.de/13099/ (2009)] shows that endogenous tariffs (or energy taxes) and endogenous labor income taxes are equivalent in generating local indeterminacy. Using methods developed by Stockman [Journal of Economic Theory 145 (2010), 1060–1085], we extend Zhang's analysis to prove that endogenous tariffs and endogenous labor income taxes are also equivalent in generating global indeterminacy (chaotic equilibria) under a balanced-budget rule. More precisely, we show that the existence of Euler equation branching in an arbitrarily small neighborhood of a steady state can imply topological chaos in the sense of Devaney. In addition, Euler equation branching occurs regardless of the local uniqueness of the equilibrium around the steady state.
Oestrogen receptor α agonist improved long-term ovariectomy-induced spatial cognition deficit in young rats
Authors: Qu Na , Wang Lei , Liu Zan-Chao , Tian Qing , Zhang Qi
Published: September 2012

Ovariectomy is known as ‘surgical menopause’ with decreased levels of oestrogen in female rodents and its reported risks and adverse effects include cognitive impairment. In the brain, oestrogen exerts effects through its receptors, oestrogen receptor α (ERα) and β (ERβ). However, the role of ERα or ERβ in ovariectomy-induced cognitive impairment needs further investigation. Here, we observed that bilaterally ovariectomized 3-month-old rats showed obvious spatial learning and memory deficits in the Morris water maze with significant loss of neurons and synapses in the hippocampus. In addition to the rapid decline in serum oestradiol levels, the expression of ERα, but not ERβ, was decreased in the hippocampus starting 1 wk after ovariectomy. Prompt 4,4′,4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol (PPT) treatment (1 mg/kg.d), an agonist of ERα, improved the spatial learning and memory ability of ovariectomized rats and rescued ovariectomy-induced neuron loss by up-regulating the level of BCLxl, an important anti-apoptosis protein. Furthermore, PPT treatment also improved ovariectomy-induced hippocampal synapse loss and up-regulated the levels of synaptic proteins (synapsin I, NR2A and GluR1) and the activates of CaMK Πα, ERK and Akt. Thus, these results demonstrated that ERα plays an important role in neuroprotection and that prompt ERα rescue is effective to improve hippocampal-dependent cognition deficit after long-term ovariectomy.
Commanding the commons: Constitutional enforcement and the law of the sea
Authors: JILLIONS ANDREW
Published: September 2012

What role does enforcement play in protecting the constitutional authority of international law? Can enforcement be understood as a specifically constitutional practice? I argue here that international law has a greater capacity for constitutional enforcement than sceptical accounts have tended to acknowledge. This argument is anchored in the institutional account of the authority of law offered by Hart and developed by MacCormick. This focuses on the official or administrative perceptions as the determinant of constitutional legitimacy, which offers a way to offset the scepticisms caused by gaps in the constitutional order. This establishes constitutional enforcement as a practice centred on and legitimated by the attribution of role responsibilities, rather than on the direct application or policing of the rules. I illustrate these arguments using the law of the sea, a domain where the functional difficulties of enforcement have always presented a challenge to international law’s claim to authority.
Contemporary constitutionalism and the dialectic of constituent power
Authors: THORNHILL CHRIS
Published: September 2012

This article examines the changing status of constituent power in contemporary constitutionalism. It considers how, at face value, contemporary constitutional law reflects a post-constituent constitutional order, which is defined by a rupture with classical constitutional principles, such that the extra-legal source of constitutional order is diminished. However, it argues that the common perception of a decline in constituent power in constitutional norm construction is marked by an excessively literalistic understanding of the origins of constitutional norms and practices. As an alternative, drawing on systems-theoretical methodologies, the article proposes a functionalist, sociologically attuned reconstruction of the historical content of constitutional concepts, including the concept of constituent power. Through this perspective, it explains that constituent power, in conjunction with constitutional rights, always acted, not as an externally founding source of political agency, but as an inner projection of the political system, which served the internal organization of the political system as a distinct societal domain. The article concludes that the transnational constitutional models which are widespread in contemporary society, far from negating constituent power, re-articulate its primary functions, and they realize potentials for preserving the autonomy of the political system which constituent power always contained.
Modification of Subjective Cognitive Outcomes in Older Persons Through Memory Training
Authors: Stepankova Hana , Lukavsky Jiri , Kopecek Miloslav , Steinova Dana , Ripova Daniela
Published: September 2012

Memory training is one way to achieve improvement in the quality of life and to prolong the independence of older people. Our contribution is a trial with one treatment group (N = 152) which concentrated on the effect of a basic memory training course available nationwide in the Czech Republic. The sample included nondemented, community-dwelling senior citizens. An important feature of the study is the inclusion of significant others who reported their observations. Results show that the training had a positive effect on the self-cognitions of the participants (rating of memory in general and ability to learn new things). The positive effect on memory and self-confidence in one’s own abilities was also reported by the significant others.
Geropsychology in Spain
Authors: Santacreu Marta
Published: September 2012

Spain, like other developed countries, has witnessed exponential growth in the number of older persons, and it has made great efforts to address this new social situation, gradually developing an extensive network for supporting not only dependent persons, but also healthy retired people with new demands. In order to better understand the situation with respect to aging, this chapter provides some demographic indicators illustrating the current structure of Spain’s aging population. The second and third sections outline the main research areas in Spain and the resources available for older adults. With regard to research on aging, there has been a considerable increase in the number of both research projects and publications in the Spanish context, particularly from the 1980s to the present. Most of the studies are aimed at assessing the different characteristics and conditions of senior citizens. This is a good first step with a view toward identifying their demands, though more research is necessary for making crucial changes. On the subject of resources and services, Spain has developed a wide variety of resources designed to meet the needs of both independent and dependent older adults. Finally, it should always be borne in mind that social needs change over time, so that they must be continuously studied and reappraised – and our respective responses updated – in order to maintain standards of excellence.
Great Lakes agreement calls for binational science priorities and action
Authors: Showstack Randy
Published: September 2012

An amended Great Lakes Water Quality Agreement (GLWQA), signed by officials from Canada and the United States at a 7 September ceremony in Washington, D. C., will facilitate efforts by the two countries to “restore and maintain the chemical, physical, and biological integrity of the Waters of the Great Lakes.” The agreement calls on the countries to cooperate and collaborate; develop programs, practices, and technology necessary to better understand the Great Lakes Basin ecosystem; and eliminate or reduce environmental threats to Great Lakes waters. The amended GLWQA specifically calls for the establishment of “binational priorities for science and action to address current and future threats” to the quality of Great Lakes waters within 18 months. In addition, the agreement calls on the International Joint Commission (IJC) to establish a Great Lakes science advisory board.
Report examines potential impacts of glacial change in Himalayas
Authors: Showstack Randy
Published: September 2012

Glaciers appear to be retreating at accelerating rates in the eastern and central regions of the Himalayas, although in the western Himalayas they appear to be more stable and may be advancing, according to a 12 September report by a committee of the U.S. National Research Council that examines climate change, water resources, and water security issues in the region. The report highlights several themes in considering the link between people and the environment within the context of water security in the Hindu Kush‐Himalayan (HKH) region. Among the themes are that there is significant variability in climate, hydrology, and glacier behavior within HKH that makes it difficult to generalize observations and findings across the region and that there is also variability in demographics and water use patterns. Other themes in the report are that uncertainties exist in the region's physical and social systems, including the effect of increased urbanization and changes in standards of living; improved monitoring of physical and social systems is needed to reduce and respond to uncertainty; and improved water management and hazard mitigation systems are the most compelling needs. For more information, see http://www.nap.edu/catalog.php?record_id=13449.
Honors
Authors: Anonymous
Published: September 2012

The Scientific Committee on Antarctic Research (SCAR) recently honored three AGU members. SCAR awarded its Medal for International Scientific Coordination to Ian Allison, senior principal research scientist and leader of the Ice, Ocean, Atmosphere and Climate Program for the Australian Antarctic Division, an agency of the government's Department of Sustainability, Environment, Water, Population and Communities. The citation noted that he has played a lead role for 30 years in international collaboration in climate science and that he “has investigated the Antarctic cryosphere for more than 40 years and participated in or led 25 research expeditions to the Antarctic.” Montana State University professor John Priscu was awarded the SCAR Medal for Excellence in Antarctic Research. Priscu “has been studying the microbial ecology of Antarctic ecosystems for almost 30 years and is one of the leaders in the investigation of sub‐glacial biogeochemical processes,” the award citation states. “His contributions to Antarctic science have been numerous, and his impact is great. John's work has been of the highest quality, and his approach to Antarctic limnology, biogeochemistry and cryospheric ecology have been extremely innovative and will be the benchmark for others to follow. He has literally discovered life in many places where no one has expected it.”
Interdisciplinary cooperation on impacts of climate change in the Arctic
Authors: Wardell Lois , Chen Linling , Strey Sara
Published: September 2012

Impact of Climate Change on Resources, Maritime Transport and Geopolitics in the Arctic and the Svalbard Area; Svalbard, Norway, 21–28 August 2011 Drastic changes in the Arctic climate directly relate to resource and transport development and complex geopolitical challenges in the Arctic. To encourage future interdisciplinary cooperation among political, social, and climate scientists, 30 early‐career researchers from varied backgrounds—including climate change, resources, polar maritime transport, and geopolitics—assembled in Svalbard, Norway. Ola Johannessen, president of the Norwegian Scientific Academy of Polar Research, led this diverse group to highlight the importance of collaboration across disciplines for broadening the terms in which assessments are defined, thus collapsing distinctions between the physical and the human Arctic. He also highlighted the feasibility of conducting effective assessment exercises within short time frames. The group was also mentored by Willy Østreng, author of Science Without Boundaries: Interdisciplinarity in Research, Society, and Politics, who aided participants in understanding the process of interdisciplinary collaboration rather than creating an assemblage of discrete findings.
Active sand dunes are largest dust source in the Sahara Desert
Authors: Bhattacharya Atreyee
Published: September 2012

Dried up lakebeds and playas in the Sahara Desert of North Africa are large sources of dust in the atmosphere. The Bodélé Depression at the southern edge of the Sahara Desert, for example, is the single largest source of dust in the world; on average, 100 dust storms a year originate from the Bodélé Depression. A new study by Crouvi et al., however, finds that active sand dunes could be even bigger sources of desert dust in the atmosphere. Atmospheric dust plays active roles in climate and biological processes in the ocean: It regulates heating at the surface of the Earth; modifies cloud properties that affect rainfall; and acts as the only source of iron, a critical nutrient for microorganisms in the ocean. Little is known about types of dust sources in the Sahara Desert, which alone accounts for more than 50% of the dust in the atmosphere.
No change in African dust transport over past 45 years
Authors: Schultz Colin
Published: September 2012

The long‐distance transport of dust around the planet has important implications for ecosystem stability and global climate dynamics. In some cases, most prominently the vast Amazon rainforest, travelling dust is the primary source of iron and phosphorous to otherwise nutrient‐limited regions. Wind‐swept sediments can affect the planetary albedo and sully the surface of icy regions driving increased melting. Therefore, understanding how ongoing climate change may affect the wind circulation patterns in major dust‐generating regions is particularly important. Unfortunately, hostile environmental conditions in many of the important sources of dust mean that long‐term wind speed and direction records from on‐the‐ground anemometers are nonexistent.
Lithospheric mantle thickness gradient focuses seismic activity
Authors: Schultz Colin
Published: September 2012

Using an array of 556 seismic sensors, Levander and Miller charted two key features of the subsurface structure of the western continental United States, with implications for explaining the locations of seismic and volcanic activity. The solid crust and the solid mantle of the Earth combine to form the lithosphere; together they overlay the plastic mantle of the asthenosphere. Deeper still are the upper and lower mantles and the liquid and solid cores. The boundary between the crust and the solid mantle is known as the Mohorovičić discontinuity (Moho), and the one between the solid and plastic mantle is the lithosphere‐asthenosphere boundary (LAB). Measuring seismic waves produced by 163 earthquakes from 2005 to 2009, the authors charted the depth of Moho and LAB in the western United States and thus the thickness of the solid lithospheric mantle.
How well do climate models simulate cloud vertical structure? A comparison between CALIPSO‐GOCCP satellite observations and CMIP5 models
Authors: Cesana G. , Chepfer H.
Published: September 2012

The Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite provides robust and global direct measurements of the cloud vertical structure. The GCM‐Oriented CALIPSO Cloud Product is used to evaluate the simulated clouds in five climate models using a lidar simulator. The total cloud cover is underestimated in all models (51% to 62% vs. 64% in observations) except in the Arctic. Continental cloud covers (at low, mid, high altitudes) are highly variable depending on the model. In the tropics, the top of deep convective clouds varies between 14 and 18 km in the models versus 16 km in the observations, and all models underestimate the low cloud amount (16% to 25%) compared to observations (29%). In the Arctic, the modeled low cloud amounts (37% to 57%) are slightly biased compared to observations (44%), and the models do not reproduce the observed seasonal variation.
Amplitude and timing of the Laschamp geomagnetic dipole low from the global atmospheric 10Be overproduction: Contribution of authigenic 10Be/9Be ratios in west equatorial Pacific sediments
Authors: Ménabréaz L. , Bourlès D. L. , Thouveny N.
Published: September 2012

Authigenic 10Be/9Be ratios were measured along a sediment core collected in the west equatorial Pacific in order to reconstruct cosmogenic 10Be production variations near the equator, where the geomagnetic modulation is maximum. From 60 to 20 ka, the single significant 10Be production impulse recorded at 41 ka results from the geomagnetic dipole low that triggered the Laschamp excursion. No significant 10Be overproduction signature is recorded at the age of the Mono Lake excursion (∼34 ka). A compilation of authigenic 10Be/9Be records obtained from sediments was averaged over a 1 kyr window and compared with the 1 kyr averaged 10Be flux record of Greenland ice cores. Their remarkable similarity demonstrates that 10Be production is globally modulated by geomagnetic dipole variations and redistributed by atmosphere dynamics. After calibration using absolute values of the virtual dipole moment drawn from paleomagnetic database, the authigenic 10Be/9Be stack allows reconstructing the geomagnetic dipole moment variations over the 20–50 ka time interval. Between 48 and 41 ka, the dipole moment collapsed at a rate of −1.5 × 1022 A m2 kyr−1, which will be an interesting criterion for the assessment of the loss rate of the historical field and the comparison of dipole moment loss prior to excursions and reversals. After a 2 kyr duration of the minimum dipole moment (∼1 × 1022 A m2), a slow increase started at 39 ka, progressively reaching 5 × 1022 A m2 at 20 ka. The absence of a significant dipole moment drop at 34 ka, the age of the Mono lake excursion, suggests that the duration and amplitude of the dipole weakening cannot be compared with that of the Laschamp. This study provides a reliable basis to model the production of radiocarbon and in situ cosmogenic nuclides and to improve the calibration of these dating methods.
On the lack of a magnetic signature of Triton's magnetospheric interaction on the Voyager 2 flyby trajectory
Authors: Neubauer F. M. , Lüttgen Andrea , Ness N. F.
Published: September 2012

There is strong, albeit indirect, evidence for a sub‐Alfvénic and transsonic interaction between Triton and the Neptunian magnetosphere. A new inspection of magnetic field data around Triton encounter shows no evidence for the interaction. It is shown that this is due to the geometry of Triton's Alfvénic wings, which were probably too far from the spacecraft during the encounter. The situation is complicated by finite ion gyroradius effects, which tend to smear out the simple Alfvén wings such as encountered at Io.
The magnetic field of Neptune
Authors: Connerney J. E. P. , Acuña Mario H. , Ness Norman F.
Published: September 2012

A spherical harmonic model of the planetary magnetic field of Neptune is obtained from the Voyager 2 encounter observations. The model is obtained by partial solution to the underdetermined inverse problem (eighth‐order and degree spherical harmonic model) using generalized inverse techniques. Dipole and quadrupole Schmidt‐normalized spherical harmonic coefficients are determined, or resolved, independently of higher‐order terms. Much additional information is also obtained regarding octupole and higher‐order components of the field. Model parameter resolution and uniqueness are addressed using new visual representations of the “resolution matrix.” The model yields a dipole of magnitude 0.14 GRN3, tilted by 47° toward 72° west longitude. Neptune's quadrupole is relatively large, equal to or exceeding in magnitude the (surface) dipole field. The octupole is likewise very large but less well constrained. The magnetic fields of Neptune and Uranus are very much alike and equally unlike those of the other known magnetized planets. Characteristics of this complex magnetic field are illustrated, using contour maps of the field on the planet's surface, and discussed in the context of dynamo generation in the relatively poorly conducting “ice mantle.”
Neptune's small inner satellites
Authors: Thomas P. , Veverka J.
Published: September 2012

Voyager 2 images revealed six small satellites orbiting within five planetary radii of Neptune. The largest, Proteus (1989N1), has a mean radius of 208 ± 8 km; the smallest, Naiad (1989N6), is 29 ± 6 km in radius. The four satellites for which reasonable radius measurements can be made all have geometric albedos (not accounting for opposition effects) of 0.06 at 0.48 pm. The albedos and phase coefficients of these satellites are very similar to those measured for the inner satellites of Uranus but are quite distinct from the values for Nereid (p= 0.16‐0.20, β = 0.028 magnitude/degree) as determined by Thomas et al. (this issue). Color measurements (0.4 to 0.6 μm) of Proteus show a neutral color. The two largest satellites are resolved as irregular objects and have limb roughnesses comparable to those of similar‐sized satellites of other planets. One image of Proteus shows a 150‐km crater with some overlapping smaller craters; this feature allows measurement of a rotation rate consistent with a synchronous period. The irregular shape and heavily cratered, photometrically bland surface of Proteus are consistent with characteristics of a primitive, undifferentiated object. Evidently, Proteus has escaped the tidal heating believed to have been responsible for the remarkable geologic processes on the similar‐sized bodies Miranda and Enceladus and perhaps Mimas.
Restrictions on the characteristics of Neptunian lightning
Authors: Kaiser M. L. , Zarka P. , Desch M. D. , Farrell W. M.
Published: September 2012

Although lightning‐triggered whistlers were detected by the Voyager 2 plasma wave experiment at Neptune, only four possible lightning sferics were detected by the planetary radio astronomy instrument. This low level of detection places strict limits on the characteristics of Neptunian lightning, ruling out lightning with power levels as high as those observed at Saturn or Uranus, but leaving the intriguing possibility that lightning slightly stronger than normal terrestrial lightning flashes but with much lower occurrence rate could exist. Possible scenarios to explain the observations are examined, including reduced NH3 concentration in the planet's atmosphere and an unusually slow risetime discharge process.
Search for glazed surfaces on Triton
Authors: Lee Pascal , Helfenstein Paul , Veverka Joseph
Published: September 2012

Near‐infrared reflectance spectra of Triton obtained from Earth since 1978 show several absorption bands between 0.8 and 4 μm, features attributed to CH4 and N2 and inferred to represent materials in the condensed state (Cruikshank and Brown, 1986, and Spencer et al., 1990). Clark et al. (1983) had previously proposed a frost grain metamorphism model for icy satellite surfaces, according to which freshly condensed CH4 and N2crystals would rapidly reconfigure themselves into a glaze or grow to unusually large sizes under the pressure and temperature conditions prevailing on Triton. In either case, the long path lengths apparently needed to explain the prominence of the absorptions could be provided. More recently, the Voyager 2 flyby of Triton revealed the existence of topographically smooth frozen “lava lakes” and active geyserlike plumes. The presence of the former, and the solid‐state greenhouse mechanism proposed by Smith et al. (1989) and Brown et al. (1990) to power the latter, both suggest the likely existence, at least as localized patches, of surficial clear ice. Thus smooth, even glazed areas of N2 and CH4ice might occur on Triton. We report the results of a search, at the pixel scale, for such glazed areas in Voyager 2 high‐resolution images of Triton. Glazed surfaces, if present, are expected to produce a surge in reflectance when viewed under the geometry of specular reflection (Middleton and Mungall, 1952). Atmosphere‐insensitive green and clear filter images acquired at phase angles ranging from 60° to 100°, and containing mirror points occurring over three different types of terrains (the South Polar Cap Mottled Unit, the South Polar Cap Bright Fringe, and the “Frost Band” region), have been surveyed. No smooth, glazed surfaces producing detectable specular reflection were found. The lack of evidence for glazed areas in the southern mid‐latitude regions, at least at the scale of the spatial resolution (∼3–7 km per line pair), indicates that another cause may be responsible for the prominence of Triton's spectral features. We note that the southern higher‐latitude regions in which active geyserlike plumes are located were not viewed under large enough incidence angles by Voyager 2 to allow conclusive searches for specular behavior.
Plasma waves in planetary magnetospheres
Authors: Kurth W. S. , Gurnett D. A.
Published: September 2012

With the completion of the Voyager 2 encounter with Neptune we have now surveyed the plasma wave spectra of five planetary magnetospheres: Earth, Jupiter, Saturn, Uranus, and Neptune. Here we provide a first general comparison of the various plasma wave modes at each of the planets with the use of a common format for displaying the spectra. The general conclusions are that many of the same types of wave modes are present in each of the magnetospheres, despite great differences in the magnetospheres' sizes, heliocentric distances, energy sources, plasma sources, and magnetic dipole orientations. There are, however, great differences in the relative and absolute intensity of some of the wave modes. Virtually ubiquitous in planetary magnetospheres are electron cyclotron harmonic bands and whistler mode emissions such as hiss and chorus. Ion cyclotron harmonic emissions have been observed where the observed local magnetic field strength was great enough to move these low‐frequency waves into the Voyager plasma wave receiver's frequency range. Broadband electrostatic noise has also been observed in the majority of the magnetospheres. In addition to a general survey of the magnetospheric wave modes, an initial assessment of the role of plasma waves in the precipitation of charged particles is presented. Waves seem to have obvious contributions in this aspect for Earth, Jupiter, and Uranus. Weaker wave amplitudes observed at Saturn and Neptune may possibly be due to the specific geometry of the flybys or to quiescent states of the magnetospheres during the encounters.
On the microphysical state of the surface of Triton
Authors: Eluszkiewicz Janusz
Published: September 2012

On the basis of an analysis of the microphysical processes involved in pressureless sintering of particulate materials and an examination of the physical conditions likely to prevail on Triton, it is argued that a well‐annealed transparent nitrogen layer can form on Triton at 37 K on a seasonal time scale (— 100 Earth years), provided the initial grain diameter is less than 1 fan. Slightly larger grains (in the 1‐10 pan range) are allowed if grain growth does not hinder densification, but grains larger than 100 μm will certainly not achieve seasonal densification. If densification is to occur simultaneously with deposition, an initial grain diameter of < 0.3 μm is required. The proposed layer is polycrystalline, the final grain diameter being 10–30 μm. In the north this layer is currently forming, whereas in the south it is the remnant of the layer formed during the last winter. The following observations can be explained by the presence of this layer: (1) the 2.16‐μm absorption feature, provided that in analogy to the visible absorptivity of water ice, grain boundaries do not reduce the absorptivity of flawless nitrogen ice; (2) the smoothness of the surface at the < 100‐μm scale, indicated by the absence of the opposition effect and a low thermal emissivity inferred from the analysis of Voyager ultraviolet, infrared, and imaging data; (3) the dark and bright appearance of the northern and southern hemisphere, respectively, despite the fact that frost should be currently condensing in the north and subliming in the south; if nitrogen forms a transparent layer upon condensation, Voyager may have seen a dark substrate in the north and a permanent nitrogen cap in the south; and (4) the plumes; a well‐annealed nitrogen layer would provide the “seal” required by the solid‐state greenhouse model. In addition to explaining these observations, two conclusions can be reached from the analysis presented in this paper. First, if the equatorial collar is the site of a recent snowfall, its fresh, bright and blue appearance can be understood if the characteristic size of the snowfiakes is ∼100 μm, as calculated in a recent model. For such large grains the annealing time scale exceeds 104Earth years. A recent appearance of this collar on a dark frost‐free surface would help to explain the decrease in the degree of reddening observed between 1977 and 1989. Second, the dust devils are unlikely to work on Triton if micron‐sized nitrogen grains are intermixed with the dust: the rapid sintering of such grains would provide the cohesive forces whose absence is essential in that model. An observational test of the “annealed‐layer” hypothesis to be performed during the current decade is proposed.