Loudness discomfort levels: A retrospective study comparing data from Pascoe (1988) and Washington University School of Medicine

Loudess discomfort levels (LDLs) were gathered from three Washington University School of Medicine sites, for a total of 325 subjects (total ears=454). These levels were compared to mean LDLs reported by Pascoe (1988). The results revealed that the mean LDL measured at WUSM (ie., the IHAFF procedure) is significantly different that the LDL reported by Pascoe (1988).

The counterpropagating Rossby wave perspective on Kelvin Helmholtz instability as a limiting case of a Rayleigh shear layer with zero width

The Kelvin Helmholtz (KH) problem, with zero stratification, is examined as a limiting case of the Rayleigh model of a single shear layer whose width tends to zero. The transition of the Rayleigh modal dispersion relation to the KH one, as well as the disappearance of the supermodal transient growth in the KH limit, are both rationalized from the counterpropagating Rossby wave perspective.

Occurrence of Kelvin-Helmholtz Billows in Sea-breeze Circulations

Centred at the interface between the sea-breeze and the return flow aloft, Kelvin-Helmholtz billows (KHB) are an important feature of the turbulent structure of some sea-breeze circulations (SBCs). In other SBCs, there are no prominent KHBs observed. Factors governing the appearance of billows are determined from a database of 139 sea breezes, constructed from two years of summertime surface observations at a site on the south coast of England. Post-frontal oscillations occur in the surface data for some SBCs and are interpreted as indicating possible KHBs aloft. The SBCs are formed under a wide range of synoptic conditions, enabling various measures of possible billow occurrence to be related to properties of the large-scale, ambient flow. Consistent with laboratory experiments of density currents, KHBs are suppressed for propagation into a head wind and enhanced with a tail wind. They are also found to be enhanced for stronger ambient wind speeds, while large-scale coast-parallel flow is effective in suppressing the billows.

Equatorial Kelvin waves as revealed by EOS Microwave Limb Sounder observations and European Centre for Medium-Range Weather Forecasts analyses: Evidence for slow Kelvin waves of zonal wave number 3

[1] Temperature and ozone observations from the Microwave Limb Sounder (MLS) on the EOS Aura satellite are used to study equatorial wave activity in the autumn of 2005. In contrast to previous observations for the same season in other years, the temperature anomalies in the middle and lower tropical stratosphere are found to be characterized by a strong wave-like eastward progression with zonal wave number equal to 3. Extended empirical orthogonal function (EOF) analysis reveals that the wave 3 components detected in the temperature anomalies correspond to a slow Kelvin wave with a period of 8 days and a phase speed of 19 m/s. Fluctuations associated with this Kelvin wave mode are also apparent in ozone profiles. Moreover, as expected by linear theory, the ozone fluctuations observed in the lower stratosphere are in phase with the temperature perturbations, and peak around 20–30 hPa where the mean ozone mixing ratios have the steepest vertical gradient. A search for other Kelvin wave modes has also been made using both the MLS observations and the analyses from one experiment where MLS ozone profiles are assimilated into the European Centre for Medium-Range Weather Forecasts (ECMWF) data assimilation system via a 6-hourly 3D var scheme. Our results show that the characteristics of the wave activity detected in the ECMWF temperature and ozone analyses are in good agreement with MLS data.

Redefinition of the kilogram, ampere, kelvin and mole: a proposed approach to implementing CIPM recommendation 1 (CI-2005)

The International System of Units (SI) is founded on seven base units, the metre, kilogram, second, ampere, kelvin, mole and candela corresponding to the seven base quantities of length, mass, time, electric current, thermodynamic temperature, amount of substance and luminous intensity. At its 94th meeting in October 2005, the International Committee for Weights and Measures (CIPM) adopted a recommendation on preparative steps towards redefining the kilogram, ampere, kelvin and mole so that these units are linked to exactly known values of fundamental constants. We propose here that these four base units should be given new definitions linking them to exactly defined values of the Planck constant h, elementary charge e, Boltzmann constant k and Avogadro constant NA, respectively. This would mean that six of the seven base units of the SI would be defined in terms of true invariants of nature. In addition, not only would these four fundamental constants have exactly defined values but also the uncertainties of many of the other fundamental constants of physics would be either eliminated or appreciably reduced. In this paper we present the background and discuss the merits of these proposed changes, and we also present possible wordings for the four new definitions. We also suggest a novel way to define the entire SI explicitly using such definitions without making any distinction between base units and derived units. We list a number of key points that should be addressed when the new definitions are adopted by the General Conference on Weights and Measures (CGPM), possibly by the 24th CGPM in 2011, and we discuss the implications of these changes for other aspects of metrology.

Mutamenti politico-istituzionali nella Venezia Giulia e a Trieste tra Tito e gli americani alla luce delle nuove testimonianze documentarie da Washington, 1944-1954

“La questione di Trieste”, ovvero la questione del confine italo-yugoslavo all’indomani della seconda guerra mondiale costituisce da lungo tempo oggetto di attenzione e di esame da parte della storiografia italiana e straniera. Con alcune importanti eccezioni, la ricostruzione complessiva di quelle vicende ha visto il più delle volte il prevalere di un approccio storico-diplomatico che ha reso difficile comprendere con chiarezza i rapporti e le interdipendenze fra contesto locale, contesto nazionale e contesto internazionale. Attraverso la lettura incrociata dell’ampia documentazione proveniente dai fondi dei National Archives Records Administration (NARA) questo studio tenta una rilettura delle varie fasi di sviluppo della questione nel periodo compreso tra il giugno del 1945 e l’ottobre del 1954 secondo una duplice prospettiva: nella prima parte si concentra sulla politica americana a Trieste, guardando nello specifico a due aspetti interni tra loro strettamente correlati, la gestione dell’ordine pubblico e la “strategia” del consenso da realizzarsi mediante il controllo dell’informazione da un lato e la promozione di una politica culturale dall’altro. Sono aspetti entrambi riconducibili al modello del direct rule, che conferiva al governo militare alleato (GMA) piena ed esclusiva autorità di governo sulla zona A della Venezia Giulia, e che ci appaiono centrali anche per cogliere l’interazione fra istituzioni e soggetti sociali. Nella seconda parte, invece, il modificarsi della fonte d’archivio indica un cambiamento di priorità nella politica estera americana relativa a Trieste: a margine dei negoziati internazionali, i documenti del fondo Clare Boothe Luce nelle carte dell’Ambasciata mostrano soprattutto come la questione di Trieste venne proiettata verso l’esterno, verso l’Italia in particolare, e sfruttata – principalmente dall’ambasciatrice – nell’ottica bipolare della guerra fredda per rinforzare il sostegno interno alla politica atlantica. Il saggio, dunque, si sviluppa lungo due linee: dentro e fuori Trieste, dentro 1945-1952, fuori 1953-1954, perché dalle fonti consultate sono queste ad emergere come aree di priorità nei due periodi. Abstract - English The “Trieste question”, or the question regarding the Italian - Yugoslav border after the Second World War, has been the object of careful examination in both Italian and foreign historiography for a long time. With a few important exceptions, the overall reconstruction of these events has been based for the most part on historic and diplomatic approaches, which have sometimes made it rather difficult to understand clearly the relationships and interdependences at play between local, national and international contexts. Through a comparative analysis of a large body of documents from the National Archives and Records Administration (NARA), College Park MD, this essay attempts a second reading of the various phases in which the question developed between June 1945 and October 1954, following a twofold perspective: the first part focuses on American policy for Trieste, specifically looking at two internal and closely linked aspects, on the one hand, the management of ‘law and order’, as well as a ‘strategy’ of consent, to be achieved through the control of all the means of information , and, on the other, the promotion of a cultural policy. Both aspects can be traced back to the ‘direct rule’ model, which gave the Allied Military Government (AMG) full and exclusive governing authority over Venezia Giulia’s Zone A. These issues are also fundamental to a better understanding of the relationships between institutions and social subjects. In the second part of the essay , the change in archival sources clearly indicates a new set of priorities in American foreign policy regarding Trieste: outside any international negotiations for the settlement of the question, the Clare Boothe Luce papers held in the Embassy’s archives, show how the Trieste question was focused on external concerns, Italy in particular, and exploited – above all by the ambassador – within the bi-polar optic of the Cold War, in order to strengthen internal support for Atlantic policies. The essay therefore follows two main lines of inquiry: within and outside Trieste, within in 1945-1952, and outside 1953-1954, since, from the archival sources used, these emerge as priority areas in the two periods.

Coupled Kelvin-wave and mirage-wave instabilities in semigeostrophic dynamics

A weak instability mode, associated with phase-locked counterpropagating coastal Kelvin waves in horizontal anticyclonic shear, is found in the semigeostrophic (SG) equations for stratified flow in a channel. This SG instability mode approximates a similar mode found in the Euler equations in the limit in which particle-trajectory slopes are much smaller than f/N, where f is the Coriolis frequency and N > f the buoyancy frequency. Though weak under normal parameter conditions, this instability mode is of theoretical interest because its existence accounts for the failure of an Arnol’d-type stability theorem for the SG equations. In the opposite limit, in which the particle motion is purely vertical, the Euler equations allow only buoyancy oscillations with no horizontal coupling. The SG equations, on the other hand, allow a physically spurious coastal “mirage wave,” so called because its velocity field vanishes despite a nonvanishing disturbance pressure field. Counterpropagating pairs of these waves can phase-lock to form a spurious “mirage-wave instability.” Closer examination shows that the mirage wave arises from failure of the SG approximations to be self-consistent for trajectory slopes f/N.

ENSO impact on Kelvin waves and associated tropical convection

The impact of El Nino–Southern Oscillation (ENSO) on atmospheric Kelvin waves and associated tropical convection is investigated using the ECMWF Re-Analysis, NOAA outgoing longwave radiation (OLR), and the analysis technique introduced in a previous study. It is found that the phase of ENSO has a substantial impact on Kelvin waves and associated convection over the equatorial central-eastern Pacific. El Nino (La Nina) events enhance (suppress) variability of the upper-tropospheric Kelvin wave and the associated convection there, both in extended boreal winter and summer. The mechanism of the impact is through changes in the ENSO-related thermal conditions and the ambient flow. In El Nino years, because of SST increase in the equatorial central-eastern Pacific, variability of eastward-moving convection, which is mainly associated with Kelvin waves, intensifies in the region. In addition, owing to the weakening of the equatorial eastern Pacific westerly duct in the upper troposphere in El Nino years, Kelvin waves amplify there. In La Nina years, the opposite occurs. However, the stronger westerly duct in La Nina winters allows more NH extratropical Rossby wave activity to propagate equatorward and force Kelvin waves around 200 hPa, partially offsetting the in situ weakening effect of the stronger westerlies on the waves. In general, in El Nino years Kelvin waves are more convectively and vertically coupled and propagate more upward into the lower stratosphere over the central-eastern Pacific. The ENSO impact in other regions is not clear, although in winter over the eastern Indian and western Pacific Oceans Kelvin waves and their associated convection are slightly weaker in El Nino than in La Nina years.

Washington's growth and opportunity act or Beijing's 'Overarching Brilliance': will African governments choose neither?

Growing criticism of Chinese engagement in Africa centres on the risk to African development posed by China's aggressive export policies and the threat to the Washington Consensus and African governance posed by China's 'non-interference' approach to engagement. This article challenges both these assumptions. The growth of Chinese trade has a wide range of impacts, depending on the sector in question, and the current terms of trade Washington extends to Africa under the auspices of the AGOA do not result in uniformly beneficial effects. With regard to African governance, it is argued that the 'Washington Consensus' has been based on competing and often muddled perceptions of US national interest. This fact tempers the regret felt at Washington's loss of influence over the good governance agenda. Evidence is provided to show that China can work within properly regulated countries and industries, if the African governments in question can provide fair, efficient and transparent environments in which to operate.

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