The NAIRU Concept - Measurement uncertainties, hysteresis and economic policy role

The present paper looks at the notion of a NAIRU and asks whether it continues to stand up to rigorous analysis in terms of both its theoretical underpinnings or of its empirical applicability. The paper addresses the essential questions in relation to an examination of the NAIRU, namely: firstly can it be reliably calculated ? and secondly, does the concept continue to have any relevance in terms of the micro and macro policy debate ? In relation to the first question, it is stressed that precise measurements of the NAIRU are extremely difficult to produce because any measurement process is dogged by the existence of a number of fundamental sources of uncertainty. As regards the second question, the growing unease, openly articulated in the vast literature on this topic, concerning both the theoretical and empirical underpinnings of the NAIRU, suggests caution needs to be exercised in terms of any policy role being attributed to the concept. The paper tentatively concludes that while theoretically the NAIRU is still a useful concept, its extensive empirical inadequacies render it less than useful in the macro policy context, although a case can still be made for sustaining its use as a structural indicator for cross country, labour flexibility, comparisons.nairu, non-accelerating inflation rate of unemployment

News and Surprises: Revisiting fiscal shocks in the open economy

Despite extensive research on fiscal policy effects in recent times, comprehensive studies on the international transmission of structural fiscal shocks remains limited and inconclusive. We address these shortcomings in three key ways. First, we confront the perfect foresight problem associated to anticipated fiscal shocks by incorporating a proxy for fiscal policy news into a detailed multi-country model. This is the first study to use such a proxy to empirically determine the cross-border transmission of US fiscal shocks in such a detailed setting. Second, we use a Bayesian multi-country VAR, which, unlike existing two-country model studies, fully accounts for higher-order spillover effects. Third, with this setup, our empirical results reassess the interpretation of fiscal multipliers from New-Keynesian closed-economy models. Key findings include: i) international spillovers mainly operate through trade channels (expenditure switching and boosting); ii) the transmission mechanism hinges on the recipient country’s underlying ‘growth model; and iii) higher-order spillover effects markedly amplify direct spillover effects; and iv) the exchange rate puzzle is rather an artifact of an omitted variable problem and of the policy regime

Compositional Explanation of Types and Algorithmic Debugging of Type Errors

The type systems of most typed functional programming languages are based on the Hindley-Milner type system. A practical problem with these type systems is that it is often hard to understand why a program is not type correct or a function does not have the intended type. We suggest that at the core of this problem is the difficulty of explaining why a given expression has a certain type. The type system is not defined compositionally. We propose to explain types using a variant of the Hindley-Milner type system that defines a compositional type explanation graph of principal typings. We describe how the programmer understands types by interactive navigation through the explanation graph. Furthermore, the explanation graph can be the foundation for algorithmic debugging of type errors, that is, semi-automatic localisation of the source of a type error without even having to understand the type inference steps. We implemented a prototype of a tool to explore the usefulness of the proposed methods

Young K-Ar gae of jarosite in the Mojave sample at Gale Crater, Mars.

By combining the Sample Analysis at Mars (SAM) instrument’s capabilities with those of the alpha particle X-ray spectrometer (APXS) on the Curiosity rover, radiometric K-Ar ages and 3He, 21Ne, and 36Ar exposure ages have been measured on two samples as of sol 1430. The Cumberland mudstone was found to have a K-Ar age of 4.21 ± 0.35 Ga (all uncertainties here are reported in 1σ), consistent with crater-counting estimates of the surrounding terrains. A second geochronology experiment was undertaken on the potassium-rich Windjana sandstone, which resulted in the unreasonably young and unrepeatable ages of 627 ± 50 Ma and 1710 ± 110 Ma on two different aliquots. These results were attributed to incomplete Ar extraction arising from the coarse grainsize and Ar-retentive characteristics of sanidine, the major K-bearing mineral in the sample.Recently, a drilled bedrock sample from the Murray mudstone formation (termed Mojave 2) was found by the CheMin instrument to contain approximately 3.1 wt% jarosite. Jarosite is precipitated from acidic, sulfate-rich waters and is a suitable mineral for KAr dating. On a large scale, jarosite has been thought to signal the aridification of Mars and a shift towards a cold, dry environment. The small amount of jarosite in this sample prohibits generalization to a larger Martian context. However, since jarosite forms strictly through interaction with water, the K-Ar age of the jarosite in Mojave 2 puts a maximum age constraint on the last time liquid water was present at the sample site. By extension, it could also indicate the time of the very final stages of evaporation from the lake in Gale Crater.A two-step heating experiment was designed to obtain the K-Ar age of the jarosite, which accounts for about 20% of the K2O in the sample. The remainder of the K2O exists in plagioclase, an amorphous component, and possibly a small amount in K-bearing phyllosilicates

Interactive Data Representation Migration: Exploiting Program Dependence to Aid Program Transformation

International audienceData representation migration is a program transformation that involves changing the type of a particular data structure, and then updating all of the operations that somehow depend on that data structure according to the new type. Changing the data representation can provide benefits such as improving efficiency and improving the quality of the computed results. Performing such a transformation is challenging, because it requires applying data-type specific changes to code fragments that may be widely scattered throughout the source code, connected by dataflow dependencies. Refactoring systems are typically sensitive to dataflow dependencies, but are not programmable with respect to the features of particular data types. Existing program transformation languages provide the needed flexibility, but do not concisely support reasoning about dataflow dependencies.To address the needs of data representation migration, we propose a new approach to program transformation that relies on a notion of semantic dependency: every transformation step propagates the transformation process onward to code that somehow depends on the transformed code. Our approach provides a declarative transformation-specification language, for expressing type-specific transformation rules. We further provide scoped rules, a mechanism for guiding rule application, and tags, a device for simple program analysis within our framework, to enable more powerful program transformations.We have implemented a prototype transformation system based on these ideas for C and C++ code and evaluate it against three example specifications, including vectorization, transformation of integers to big integers, and transformation of array-of-structures data types to structure-of-arrays format. Our evaluation shows that our approach can improve program performance and the precision of the computed results, and that it scales to programs of up to 3700 lines

Political mobilisation by minorities in Britain: negative feedback of ‘race relations'?

This article uses a political opportunity approach to study the relationship of minority groups to the political community in Britain. The main argument is that the British race relations approach established in the 1960s had an important effect that still shapes the patterns of political contention by different minority groups today. Original data on political claims-making by minorities demonstrate that British 'racialised' cultural pluralism has structured an inequality of opportunities for the two main groups, African-Caribbeans and Indian subcontinent minorities. African-Caribbeans mobilise along racial lines, use a strongly assimilative 'black' identity, conventional action forms, and target state institutions with demands for justice that are framed within the recognised framework of race relations. Conversely, a high proportion of the Indian subcontinent minority mobilisation is by Muslim groups, a non-assimilative religious identity. These are autonomously organised, but largely make public demands for extending the principle of racial equality to their non-racial group. Within the Indian subcontinent minorities, the relative absence of mobilisation by Indian, Sikh and Hindu minorities, who have achieved much better levels of socio-economic success than Pakistani and Bangladeshi Muslims, suggests that there is also a strong socioeconomic basis for shared experiences and grievances as Muslims in Britain. This relativises the notion that Muslim mobilisation is Britain is purely an expression of the right for cultural difference per se, and sees it as a product of the paradoxes of British race relations

Glen Torridon Mineralogy and the Sedimentary History of the Clay Mineral Bearing Unit

Clay minerals are common in ancient terrains on Mars and their presence at the surface alludes to aqueous processes in the Noachian to Early Hesperian (>3.5 Ga). Gale crater was selected as Curiositys landing site largely because of the identification of clay mineral rich strata from orbit. On Earth, the types of clay minerals (i.e., smectites) identified in Gale crater are typically juvenile weathering products that ultimately record the interaction between primary igneous minerals with the hydrosphere, atmosphere, and biosphere. Trioctahedral and dioctahedral smectite were identified by Curiosity in units stratigraphically below the Clay Mineral-Bearing Unit (CBU) identified from orbit. Compositional and sedimentological data suggest the smectite formed via authigenesis in a lake environment and may have been altered during early diagenesis. The CBU is stratigraphically equivalent to a hematite-rich unit to the north and stratigraphically underlies sulfate-rich units to the south, suggesting a dynamic environment and evolving history of water in the ancient Gale crater lake. Targeting these clay mineral rich areas on Mars with rover missions provides an opportunity to explore the aqueous and sedimentary history of the planet

Mineralogy of Vera Rubin Ridge in Gale Crater from the Mars Science Laboratory CheMin instrument

Gale crater was selected as the landing site for the Mars Science Laboratory Curiosity rover because of orbital evidence for a variety of secondary minerals in the lower slopes of Aeolis Mons (aka Mount Sharp) that indicate changes in aqueous conditions over time. Distinct units demonstrate orbital spectral signatures of hematite, phyllosilicate (smectite), and sulfate minerals, which suggest that ancient aqueous environments in Gale crater varied in oxidation potential, pH, and water activity. Vera Rubin ridge (VRR) is the first of these units identified from orbit to have been studied by Curiosity. Orbital near-infrared data from VRR show a strong band at 860 nm indicative of hematite. Before Curiosity arrived at VRR, the hypotheses to explain the formation of hematite included (1) precipitation at a redox interface where aqueous Fe2+ was oxidized to Fe3+, and (2) acidic alteration of olivine in oxic fluids. Studying the composition and sedimentology of the rocks on VRR allow us to test and refine these hypotheses and flesh out the depositional and diagenetic history of the ridge. Here, we focus on the mineralogical results of four rock powders drilled from and immediately below VRR as determined by CheMin

Removal processes for tributyltin during municipal wastewater treatment

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Springer.The fate and behaviour of tributyltin (TBT) at two wastewater treatment works was examined. Both sites had two inlet streams, and each utilised high rate biological filters (biofilters) on one the streams, before treatment of the combined flows on trickling filters, with one having additional tertiary processes, installed to remove ammonia and solids. The study was designed to determine if these processes enhanced the removal of TBT. Degradation of TBT was observed in one of the biofilters, possibly as a result of temperature and hydraulic loading. At the treatment works with tertiary processes, the mass flux showed the overall removal of TBT was 68 %, predominantly due to removal with solids in the primary settlement processes. However, overall removal of 95 % was observed in the conventional trickling filter works with 94 % of this due to biodegradation in the trickling filter. The two works both removed TBT, but at different treatment stages and by different processes. Differences in the form (solubility) of TBT in the influent may have attributed to this, although further understanding of factors controlling degradation would allow for a more complete assessment of the potential of biological processes to remove hazardous compounds from wastewaters.United Utilities PL

SAM-Like Evolved Gas Analyses of Phyllosilicate Minerals and Applications to SAM Analyses of the Sheepbed Mudstone, Gale Crater, Mars

While in Yellowknife Bay, the Mars Science Laboratory Curiosity rover collected two drilled samples, John Klein (hereafter "JK") and Cumberland ("CB"), from the Sheepbed mudstone, as well as a scooped sample from the Rocknest aeolian bedform ("RN"). These samples were sieved by Curiosity's sample processing system and then several subsamples of these materials were delivered to the Sample Analysis at Mars (SAM) instrument suite and the CheMin X-ray diffraction/X-ray fluorescence instrument. CheMin provided the first in situ X-ray diffraction-based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., Fe-saponite) and comprise ~20 wt% of the mudstone samples [1]. SAM's evolved gas analysis (EGA) mass spectrometry analyses of JK and CB subsamples, as well as RN subsamples, detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, OCS, CS2 and other trace gases evolved during pyrolysis. The identity of evolved gases and temperature( s) of evolution can augment mineral detection by CheMin and place constraints on trace volatile-bearing phases present below the CheMin detection limit or those phases difficult to characterize with XRD (e.g., X-ray amorphous phases). Here we will focus on the SAM H2O data, in the context of CheMin analyses, and comparisons to laboratory SAM-like analyses of several phyllosilicate minerals including smectites