Episodes Of Growth Research Articles

The complex dynamic of growth: Fitness and the different patterns of economic activity in the medium and long terms

When analyzing countries’ medium- and long-term economic performance, it is important to study jointly the dynamic of growth and the industrial evolution that determines how the productive structure changes over time. In this paper, we use the Economic Fitness metric to describe the competitiveness of the countries' industrial structure, and classify economic episodes, with five-years windows, to establish how countries grow (i.e., above or below a trend, and with a dynamic or static industrial structure.) We show a complex growth dynamic using data covering two decades (1995–2014) for a large set of countries. This pattern indicates that the observed sequences of spells vary substantially even between countries within the same growth regime (low, medium, and high). Moreover, we find a robust statistical relationship between these spells and Economic Fitness with a multinomial econometric model. In particular, we show that economies with higher fitness are more resilient since episodes of below-average growth and the net disappearance of competitive firms are less likely to happen.

Ridge subduction and episodes of crustal growth in accretionary belts: Evidence from late Paleozoic felsic igneous rocks in the southeastern Central Asian Orogenic Belt, Inner Mongolia, China

Abstract The Central Asian Orogenic Belt (CAOB) is one of the largest accretionary orogens on Earth and preserves evidence that more than 50% of this orogen represents juvenile crustal growth over an extended period of some 750 million years from ca. 1000 Ma to ca. 250 Ma. However, the mechanism of crustal growth is controversial, as implied by a variety of proposed models ranging from contributions of mantle-derived basaltic underplating in a post-collisional extensional setting to subduction-related processes in an island arc setting. To distinguish among these models, we report petrological, geochemical, whole-rock Sr-Nd isotope and zircon U-Pb and Hf isotope analyses of late Paleozoic felsic igneous rocks from the northern Inner Mongolia region, southeastern CAOB. New zircon U-Pb analyses of three plutonic and extrusive magmatic suites yield Late Carboniferous to Early Permian ages of 319–279 Ma. The Xi Ujimqin granodiorites have low-K tholeiitic to calc-alkaline, metaluminous to weakly peraluminous compositions, and are magnesian I-type granitoids. These granitoids are also characterized by relatively high MgO and Sr contents, high Mg# values, mid-ocean ridge basalt (MORB)-like Nd-Hf isotope compositions and young Nd-Hf model ages of 600–298 Ma. These features indicate that the parental magmas of the Xi Ujimqin I-type granitoids originated from a depleted lithospheric mantle that had been metasomatized by fluids released from a subducting slab. By contrast, the Xilinhot alkali-feldspar granites and Dashizhai rhyolites display geochemical signatures of ferroan granites. These, together with their moderately depleted Nd-Hf isotope compositions and young Nd-Hf model ages of 809–277 Ma, suggest that they were produced by re-melting of juvenile lower crust via underplating of mantle-derived magmas. The coexistence of an association of boninite-adakite-high-Mg andesite-Nb-enriched basalt, and MORB to ocean island basalt-type mafic rocks in the northern Inner Mongolia region implies a dramatic change in composition from fluid-related calc-alkaline arc magmatism to melt-related and mantle-derived magmatism initiated by upwelling asthenosphere. We infer that ridge subduction may have occurred in this region during Late Carboniferous to Early Permian. Combined with previous studies, there are two ridge subduction events during the early and late Paleozoic in Inner Mongolia within the southeastern CAOB, which coincide with two large-volume magmatic flare-ups (300 ± 20 and 450 ± 20 Ma). Furthermore, our model calculations suggest that most of the juvenile crust in the southeastern CAOB was generated in a relatively short interval (~20–40 m.y.) during each long-lived tectonic cycle (>140 m.y. spanning oceanic rifting, subduction, and collision) of magmatic activity. Ridge subduction may have played a significant role in the rhythmic growth of juvenile crust in the CAOB during the Phanerozoic. Repeated cycles of punctuated, rapid growth of juvenile crust associated with long-lived subduction systems represent a pattern that may be generalized to other Phanerozoic accretionary belts on Earth.

Specialize or diversify? And in What? Trade composition, quality of specialization, and persistent growth

Abstract This paper, using a long-term, product-level, cross-country dataset, analyzes the trade–growth nexus by introducing two novel indicators able to capture demand and supply attributes of countries’ quality of specialization. The Keynesian efficiency index measures demand attractiveness of the export baskets, estimating product-level demand elasticities and weighting them by diversification; the Schumpeterian efficiency index tracks the export baskets’ technological dynamism proxied by product-level patent intensities. These two dimensions of quality of specialization are effective in explaining the rate and volatility of growth and the duration of growth episodes, identified as periods longer than 8 years of 2% average growth and, even more, of exceptional growth episodes ($\geq\,5\%$). Our results, robust to a wide range of control variables, suggest that specialization per sé is detrimental for growth resilience while countries with a diversified export structure specialized either in demand-elastic and technological-dynamic productions are likely to experience longer growth episodes.

Probabilistic analysis to correlate seismic data with lava extrusion phases at Merapi volcano (Indonesia)

Volcanoes can produce a range of eruptive behavior even during a single eruption, changing quickly from effusive to explosive style, and the other way around. The changes in eruption phases (e.g. phreatic explosion, magmatic explosion, lava extrusion, etc.) can lead to different volcanic hazards and require timely assessment for the implementation of mitigation measures. Here we explore how to correlate a given eruption phase with changes in the monitoring data using statistical analysis and conditional probabilities. We calculate the success of detection of an eruption phase using a threshold of monitoring data, which includes the uncertainty on the eruption phase dates with a Monte Carlo simulation. We apply the method to dome forming eruptions of Mt. Merapi (Indonesia) and evaluate their time occurrence using an exceptionally long monitoring time series (from 1993 to 2012, over nineteen years) of Multiphase (Hybrid) Seismic Energy. We identify the seismic energy threshold that is associated with the lava extrusion phase with an accuracy of 90 ±2%, precision of 73 ± 2%, specificity of 96 ± 1%, and sensitivity of 56 ± 1%. We further test our method with the recent 2018 eruption (not used in the thresholds calculations) and we identify the lava extrusion with a precision of 67%, specificity of 70%, and sensitivity of 92%. We also seismically detected the 2018′s onset of the lava extrusion phase 14 days earlier than the visual observation. Given the link between dome-collapse pyroclastic flows and growth episodes of the lava dome at Merapi, our analysis also allows us to establish that 83% of the most energetic pyroclastic flows occur within the first 3 months after the onset of lava extrusion phase. Our method can be applicable to a range of time series of monitoring data (seismic, deformation, gas) and to other volcanoes that have a significant number of past events.

The Foundation of Monte Albán, Intensification, and Growth: Coactive Processes and Joint Production

Most early sedentary villages (c. 1500–500 BCE) in the Valley of Oaxaca, Mexico, were situated on or near well-watered land. Around 500 BCE, a new hilltop center, Monte Albán, was established at the nexus of the valley's three arms, where agriculture was far riskier due to unreliable rainfall and a dearth of permanent water sources. During the era of its establishment, not only was Monte Albán larger than any earlier community in the region, but many other settlers moved into the rural area around Monte Albán. This marked shift in settlement patterns in the Valley of Oaxaca and the underlying processes associated with the foundation of Monte Albán have long been debated. How can we account for the immigration of people, some likely from beyond the region itself, to an area where they faced greater risks of crop failure? One perspective, reliant on uniform models of premodern states as despotic, viewed the process from a basically top-down lens; leaders coerced subalterns to move near the capital to provide sustenance for the new center. Yet more recent research has found that governance at Monte Albán was generally more collective than autocratic, and productive activities were centered in domestic units and not managed from above. Based on these new empirical foundations, we reassess earlier settlement and land use studies for the Valley of Oaxaca and view this critical transition as initiated through coactive processes in which new institutions were formed and new relations forged. Shifts in defense, ritual, domestic organization, craft production, and exchange all coincided with this episode of growth fostered by joint production, which intensified agrarian yields through increased domestic labor investments.

High growth episodes among R&D intensive firms: Evidence for Europe, US and Japan

The purpose of this article is three-fold: first, it tests whether inter-industry R&D spillovers are positively associated with the likelihood of experiencing high growth episodes among R&D intensive firms in Europe, US and Japan; second, it tests whether such a relationship is conditional on their level of absorptive capacity (ACAP); third, it tests whether the acquisition of foreign patents, an additional channel to access external knowledge, trigger high growth episodes among a sub-set of R&D intensive firms. For the empirical analysis, we focus on R&D intensive manufacturing firms observed between 2002 and 2017, located in Europe, US and Japan. The empirical findings support the hypotheses suggesting that: a) inter-industry R&D spillovers are associated with the likelihood of experiencing high growth episodes; b) ACAP conditions the relationship between inter-industry R&D spillovers and the likelihood of experiencing high growth episodes and c) shares of foreign patents are positively associated with the likelihood of experiencing high growth episodes among high-tech R&D intensive firms. JEL codes: C41, L25, O33.

The rare earth element geochemistry of mafic granulites from the Neoarchaean northern marginal zone of the Limpopo Belt, Zimbabwe: Insights into mantle processes during an episode of crustal growth

The granulites of the Northern Marginal Zone of the Limpopo belt, Zimbabwe represent the lower crust of the Zimbabwe Craton. They are predominantly felsic in composition and represent magmas of the tonalite-trondhjemite-granodiorite suite which formed during a period of major crustal growth in the Neoarchaean. However, enclosed within the felsic gneisses of the NMZ are mafic granulites (metabasalts) which make up between 5 and 10% of the rock volume and which both predate and post-date the main TTG magmatism. These rocks show a diverse range of trace element compositions and are used here to characterize those mantle processes which were taking place during this period of crustal growth.The mafic granulites can be subdivided into two main groups. 1. Large metabasite lenses, associated with banded iron formation, represent a supracrustal suite of basalts which predate the emplacement of the TTGs and may be time equivalents of the lower greenstones of the Zimbabwe Craton. Samples can be grouped into three different types of REE pattern – depleted, chondritic and enriched – which is interpreted to show that they were partial melts of a depleted mantle source, which in places interacted with and was contaminated with older felsic crust. 2. Narrow dykes post-date the emplacement of the NMZ TTG suite. There are two geochemical types. Dykes with light-enriched REE patterns are derived from a depleted mantle source but were contaminated with felsic crust during their emplacement. Dykes highly enriched in light REE were derived from an enriched mantle source formed through the refertilisation of a previously depleted mantle source. The deep melting of this refertilised source gave rise to highly enriched mafic melts.The large metabasite lenses could be indicative of the metabasaltic source which subsequently partially melted to form the NMZ TTG magmatic suite. Later deep mantle melting to form the post TTG dykes may be related to the creation of thick Neoarchaean continental crust and associated mantle lithosphere.

Boron release and transfer induced by phengite breakdown in subducted impure metacarbonates

White mica is an important reservoir of boron (B) in subducted metasedimentary rocks. To quantify the effect of phengite breakdown on B release and transfer, we investigated the replacement processes of phengitic mica and associated element redistribution in exhumed ultra-high pressure (UHP) impure marbles from the Dabie terrane, China. Three types of microstructures, which are related to the liberation, transport, and precipitation of B, are recognized: (1) Type-I is the pseudomorphic replacement of phengite by the assemblage of biotite + plagioclase ± quartz ± epidote. The assemblage maintains a flaky shape of pre-existing phengite, which only rarely occurs as a relict phase in the product assemblages. Phase equilibria modelling indicates that the conditions of replacement reactions are 1.2–1.3 GPa at ~600 °C, with a relatively low XCO2 of 0.04–0.16. (2) Type-II is characterized by the local occurrence of fine-grained tourmaline (Tur-F) along the outer margin of Type-I texture domains, which represents the in situ precipitation of B released by the replacement reactions. (3) Type-III texture involves the irregularly shaped intergrowth of tourmaline (Tur-In) + quartz in the calcite matrix, isolated from the Type-I and Type-II texture domains. The Type-III minerals are in equilibrium with diopside and plagioclase and most likely represent the precipitation from a “transported”, B-bearing fluid.Mineral trace element analyses indicate that relict phengite in Type-I texture has significantly higher B contents (284–464 μg/g) than all of the product minerals (2–26 μg/g). A mass balance estimate indicates that the majority (>90%) of B in the reactants is lost during the process of phengite replacement. The calculations in terms of mineral-fluid partition indicate that the fluid involved in the replacement reactions has B contents of 1893–6858 μg/g. In situ B isotopic analyses indicate that Tur-F and Tur-In have a similar variation range of δ11B (+4 ~ +7‰). Both types of low-pressure tourmaline have lower δ11B values than the previously reported eclogite-facies tourmaline (reaching +15‰) from phengite-bearing marbles in the same study area. This result indicates two episodes of tourmaline growth and B transfer. Thus, a two-stage model of B loss from phengite during slab exhumation is proposed. Our results reveal that the breakdown of white mica in exhumed metasedimentary rocks can cause a strong release of B, which would largely influence the B budget at convergent plate margins.

Direct zirconU–Pbevidence forpre‐Himalayan HTmetamorphism in the Higher Himalayan Crystallines, eastern Garhwal Himalaya, India

The high‐grade Higher Himalayan Crystallines (HHC), located between the South Tibetan Detachment System and Main Central Thrust in the collision zone between the Indo‐Australian and Eurasian plates, have been subject to at least four significant phases of deformation and metamorphism. The earliest of those significantly predates the Cenozoic continent‐continent collision, but has been difficult to date isotopically because of later overprinting. Migmatitic paragneiss from the Badrinath Formation in the Dhauliganga Valley, northern Uttarakhand, some of the highest‐grade rocks in the HHC, preserves direct evidence of mid‐Ordovician metamorphism in the form of 465.8 ± 6.4 Ma zircon overgrowths with extremely low Th/U (0.0038–0.0074). The overgrowths have formed on ca. 2.63–0.71 Ga detrital zircon cores and are themselves overgrown by two generations of Miocene metamorphic zircon with mean Pb/U ages of ca. 21.5 and 18.2 Ma. Monazite from the same sample has a mean Pb/Th age of 19.4 ± 0.2 Ma. The oxygen isotopic compositions of the monazite (δ18O: 7.69 ± 0.08‰) and youngest zircon overgrowths (δ18O: 7.95 ± 0.12, 8.24 ± 0.09‰) are consistent with mineral growth in a metasediment, but either of the two minerals did not grow in isotopic equilibrium with each other, or the original composition of the monazite has not been preserved. If the quartz (δ18O: 13.29 ± 0.11‰) equilibrated with the youngest zircon and its composition has been preserved, then the last episode of zircon growth took place at low temperature, ca. 420°C, after the migmatization. The protolith of the Badrinath migmatite was a Neoproterozoic or Early Palaeozoic metasediment partially melted (and probably migmatized) in the Middle Ordovician. The strong planar foliation currently present in the migmatite is probably the result of mid‐crustal extrusional channel flow and HT decompressional partial melting in the Miocene.

Building a continental arc section: Constraints from Paleozoic granulite-facies metamorphism, anatexis, and magmatism in the northern margin of the Qilian Block, northern Tibet Plateau

AbstractContinental arcs in active continental margins (especially deep-seated arc magmatism, anatexis, and metamorphism) can be extremely significant in evaluating continent building processes. In this contribution, a Paleozoic continental arc section is constructed based on coeval granulite-facies metamorphism, anatexis, and magmatism on the northern margin of the Qilian Block, which record two significant episodes of continental crust growth. The deeper layer of the lower crust mainly consists of medium-high pressure mafic and felsic granulites, with apparent peak pressure-temperature conditions of 11–13 kbar and 800–950 °C, corresponding to crustal depths of ~35–45 km. The high-pressure mafic granulite and local garnet-cumulate represent mafic residues via dehydration melting involving breakdown of amphibole with anatectic garnet growth. Zircon U-Pb geochronology indicates that these high-grade metamorphic rocks experienced peak granulite-facies metamorphism at ca. 450 Ma. In the upper layer of the lower crust, the most abundant rocks are preexisting garnet-bearing metasedimentary rocks, orthogneiss, and local garnet amphibolite, which experienced medium-pressure amphibolite-facies to granulite-facies metamorphism at depths of 20–30 km at ca. 450 Ma. These metasedimentary rocks and orthogneiss have also experienced partial melting involving mica and rare amphibole at 457–453 Ma. The shallow to mid-crust is primarily composed of diorite-granodiorite batholiths and volcanic cover with multiple origin, which were intruded during 500–450 Ma, recording long-term crustal growth and differentiation episode. As a whole, two episodes of continental crust growth were depicted in the continental arc section on the northern margin of the Qilian Block, including: (a) the first episode is documented in a lithological assemblage composing of coeval mafic-intermediate intrusive and volcanic rocks derived from partial melting of modified lithospheric mantle and subducted oceanic crust during southward subduction of the North Qilian Ocean at 500–480 Ma; (b) the second episode is recorded in mafic rocks derived from partial melting of modified lithospheric mantle during transition from oceanic subduction to initial collision at 460–450 Ma.

Economic growth in Sub-Saharan Africa, 1885–2008: Evidence from eight countries

Sub-Saharan Africa (SSA) has been absent from recent debates about comparative long-run growth owing to the lack of data on aggregate economic performance before 1950. This paper provides estimates of GDP per capita on an annual basis for eight Anglophone African economies for the period since 1885, raising new questions about previous characterizations of the region's economic performance. The new data show that many of these economies had levels of per capita income which were above subsistence by the early twentieth century, on a par with the largest economies in Asia until the 1980s. However, overall improvements in GDP per capita were limited by episodes of negative growth or “shrinking”, the scale and scope of which can be measured through annual data.

Zircon U-Pb and geochemical signatures in high-pressure, low-temperature metamorphic rocks as recorders of subduction zone processes, Sikinos and Ios islands, Greece

Zircon U-Pb dating is a powerful and widely used geochronologic technique to constrain the timing and rates of magmatic and high and lower-grade metamorphic processes, as well as sediment provenance. Zircon trace element (TE) compositions also record magmatic and metamorphic processes during zircon growth. In this study, zircon laser ablation split-stream (LA-SS)-ICP-MS U-Pb and TE depth-profiling and novel two-dimensional zircon mapping techniques are used in combination with oxygen isotope analyses (secondary ion mass spectrometry, SIMS) to reconstruct the timing and metamorphic conditions recorded by recrystallization and growth of zircon rims, which provide valuable insight into the petro-tectonic evolution of high-pressure/low-temperature (HP/LT) metamorphic rocks formed in subduction zones. These techniques are applied to zircon grains from HP/LT metamorphic rocks of the Cycladic Blueschist Unit (CBU) and Cycladic Basement (CB) on Sikinos and Ios islands, Greece, which experienced metamorphism and deformation associated with subduction and subsequent back-arc exhumation. Zircon records multiple episodes of non-magmatic zircon rim growth at ~50 Ma and ~ 26 Ma. Eocene metamorphic rims are associated with HP/LT metamorphism and are observed in both units, suggesting likely juxtaposition prior to or during subduction and associated HP metamorphism. The similarity between TE concentrations and δ18O values of the Eocene rims and their corresponding cores is an indicator for re-crystallization and precipitation as a mechanism of zircon growth. In contrast, Oligocene zircon rims appear to be restricted to a < 0.5 km thick zone along the CB-CBU contact, characterized by garnet break-down, and show HREE enrichment and higher ẟ18O values in the rims compared to the cores, consistent with a model suggesting metasomatic infiltration of fluids derived from dehydrating sedimentary rocks during progressive subduction and underplating prior to back-arc extension. This metamorphism appears to be static in nature and does not support major late Cenozoic reactivation of the contact as an extensional shear zone during back-arc extension.

Dimethyl Sulfide‐Induced Increase in Cloud Condensation Nuclei in the Arctic Atmosphere

AbstractOceanic dimethyl sulfide (DMS) emissions have been recognized as a biological regulator of climate by contributing to cloud formation. Despite decades of research, the climatic role of DMS remains ambiguous largely because of limited observational evidence for DMS‐induced cloud condensation nuclei (CCN) enhancement. Here, we report concurrent measurement of DMS, physiochemical properties of aerosol particles, and CCN in the Arctic atmosphere during the phytoplankton bloom period of 2010. We encountered multiple episodes of new particle formation (NPF) and particle growth when DMS mixing ratios were both low and high. The growth of particles to sizes at which they can act as CCN accelerated in response to an increase in atmospheric DMS. Explicitly, the sequential increase in all relevant parameters (including the source rate of condensable vapor, the growth rate of particles, Aitken mode particles, hygroscopicity, and CCN) was pronounced at the DMS‐derived NPF and particle growth events. This field study unequivocally demonstrates the previously unconfirmed roles of DMS in the growth of particles into climate‐relevant size and eventual CCN activation.

Constructive and Destructive Processes During the 2018–2019 Eruption Episode at Shiveluch Volcano, Kamchatka, Studied From Satellite and Aerial Data

Dome-building volcanoes often develop by intrusion and extrusion, recurrent destabilization and sector collapses, and renewed volcanic growth inside the collapse embayment. However, details of the structural architecture affiliated with renewed volcanic activity and the influences of regional structures remain poorly understood. Here, we analyze the recent activity of Shiveluch volcano, Kamchatka Peninsula, characterized by repeated episodes of lava dome growth and destruction due to large explosions and gravity-driven collapses. We collect and process a multisensor dataset comprising high-resolution optical (aerial and tri-stereo Pleiades satellite), radar (TerraSAR-X and TanDEM-X satellites), and thermal (aerial and MODIS, Sentinel-2, and Landsat 8 satellites) data. We investigate the evolution of the 2018–2019 eruption episode and evaluate the morphological and structural changes that led to the August 29, 2019 explosive eruption and partial dome collapse. Our results show that a new massive lava lobe gradually extruded onto the SW flank of the dome, concurrent with magmatic intrusion into the eastern dome sector, adding 0.15 km3 to the lava dome complex. As the amphitheater infilled, new eruption craters emerged along a SW-NE alignment close to the amphitheater rim. Then, the large August 29, 2019 explosive eruption occurred, followed by partial dome collapse, which was initially directed away from this SW-NE trend. The eruption and collapse removed 0.11 km3 of the dome edifice and led to the formation of a new central SW-NE-elongated crater with dimensions of 430 m × 490 m, a collapse scar at the eastern part of the dome, and pyroclastic density currents that traveled ∼12 km downslope. This work sheds light on the structural architecture dominated by a SW-NE lineament and the complex interplay of volcano constructive and destructive processes. We develop a conceptual model emphasizing the relevance of structural trends, namely, 1) a SW-NE-oriented (possibly regional) structure and 2) the infilled amphitheater and its decollement surface, both of which are vital for understanding the directions of growth and collapse and for assessing the potential hazards at both Shiveluch and dome-building volcanoes elsewhere.

High-Frequency Repeated Measures of Over 5,000 Infants Aged 6–27 Months Reveals Pattern of Growth Faltering in Rural Burkina Faso

ObjectivesLinear growth faltering, failure to achieve one’s potential for length or height at each age, is associated with increased risk of mortality and morbidity. Understanding the age-related patterns of growth faltering can inform timing of interventions and policies for prevention; however current knowledge is limited by cross-sectional data. We examine the longitudinal characterization of the timing of growth faltering among young children. MethodsUsing longitudinal anthropometric data originally collected as part of a food-aid cost-effectiveness trial, we investigated individual growth curves of 5,039 children aged 6–27 months in Burkina Faso (108,580 total measurements) to determine whether growth faltering occurs through intermittent episodes of slower growth, or continuously slow growth. We visualized individual growth curves and used two-stage regressions to evaluate growth curve smoothness at different levels of attained length. To do this, we first obtained model fit and diagnostic parameters from individual regressions of each child’s length on their age. Parameters extracted included R2, as a metric of curve smoothness, initial length at 6 months, and average velocity. We then regressed these parameters on individual-level attained length at study end. ResultsGrowth faltering manifests as both continuously lower growth velocity throughout the observation period and greater heterogeneity in growth velocity amplitude. Children with lower attained length start smaller (Quintile 1 of attained length-63.1 cm initial length; Quintile 5-68.4 cm) and stay on their initial trajectories, continuously growing slower than their taller counterparts. In addition, a 0.01 increase in the R2 (smoothness) from regression of a child’s length on their age is associated with a 3.10 cm increase in attained length (95% CI: 2.80, 3.41), showing that smoother growth is also associated with higher attained length. ConclusionsChildren who experience the most extreme growth faltering are likely to be less resilient to systematic growth-limiting conditions as well as episodic insults to their growth. Future research should investigate ways of improving environmental conditions to support growth. Funding SourcesFinancial support provided by the Food Aid Quality Review project, funded by the United States Agency for International Development.

Dinámica transicional de la relación producción-inversión en el sector transporte de los estados mexicanos

En teoría, los cambios en la composición producción-inversión evolucionan bajo dinámicas transicionales que se estabilizan en el largo plazo. Se prueba esta hipótesis mediante un modelo de Markov aplicado al sector transporte de los estados mexicanos durante 1975-2013. Los resultados señalan que se alcanza el estado estable cuando el crecimiento del producto no se condiciona a la inversión, pero resulta en una distribución desmejorada (aumentan decrecimiento y crecimiento bajo). En cambio, el escenario condicionado logra una distribución enriquecida, ya que reduce el número de episodios de crecimiento bajo y decrecimiento, eleva el crecimiento alto y mejora a las economías menos desarrolladas; sin embargo, esta dinámica de transición fluye más lentamente. El sector transporte en México requiere mayores inversiones que aceleren la transición al estado estable.

Economic growth takeoffs and the extensive and intensive margins of trade

AbstractIn this study, we use a gravity model to investigate the relationship between exports and sudden, prolonged increases in economic growth. Our main contribution is we decompose exports into the extensive and intensive margins when considering this relationship. Using the definition of takeoffs in a country's growth process from Aizenman &amp; Spiegel, we identify 142 economic growth takeoffs. We find that the extensive margin is an important mechanism for export growth and, ultimately, economic growth. We also find evidence that exports increase significantly immediately before, and during, a growth episode, with the extensive margin being entirely responsible for the observed increase in exports. Finally, we find that developing countries see a larger percentage point increase in the extensive margin and decrease in the intensive margin during a takeoff. These results suggest that takeoffs may spur a reduction in the fixed costs to exporting, which propel an increase in the extensive margin. Therefore, export diversification appears to be a potential policy option for those seeking to increase the chances of a growth takeoff in their country, and takeoffs seem to present an opportunity for further export diversification.

The Succession of Upper Eocene- Upper Miocene Limestone Growth and Corresponding Tectonic Events in Luconia Shelf, Sarawak, Malaysia

Using high quality regional seismic lines, we evidence major structures resulting from successive phases of tectonic events that affected the Luconia shelf from the Upper Cretaceous to Pliocene. Each tectonic event (Classified as Event 1–Event 3) is associated with different episodes of limestone growth in Luconia Province. The successive limestone growths are used as markers in constraining the timing and style of tectonic deformation. The poly-stage closure of the Proto South China Sea (PSCS) from the Upper Cretaceous to Lower Miocene led to the formation of compressional structures in its southern portion (South PSCS) providing elevated topography for the growth of the oldest limestone found in this area during the Upper Eocene to Lower Oligocene (Event 1). Based on contrasting seismic reflectors, morphology, and depositional patterns, the offshore Upper Eocene-Lower Oligocene limestone growth is correlated to the onshore Engkabang-Karap limestone. The southern part of Luconia was subjected to a continuous compression until the Lower Miocene at a time where the northern side of the Luconia Province was experiencing subsidence due to the rifting of the South China Sea (Event 2). The compression in the south generated elevated anticlines, triggering the growth of the Upper Oligocene to Lower Miocene limestone. By the end of the rifting event in the Lower Miocene, tectonic quiescence had enabled widespread carbonate growth in Luconia from the Middle to Upper Miocene. Regional compression due to the major uplift of Borneo hinterland (Event 3) triggered paramount clastic influx (gravity tectonics) to the offshore perturbating the limestone reef growth in Luconia. The impact of these interrelated shortening and stretching phases led to major crustal thickness variations and a prominent tilt of the Luconia platform that may highlight intricate feedbacks at the transition from compression to extension. While the southern side of the Luconia’s crustal fragment was anchored into Borneo hinterland, crustal extension in the northern region of Luconia led to a hyper-stretched crust characterized by low angle detachment faults and highly rotated blocks rising the mantle to its shallowest.

Age disequilibrium between zircon and their granitoid hosts caused by intracrustal reworking: Nd-Hf-Ar isotope evidence of Archaean Granitoids from Barberton Mountain Land (Kaapvaal craton, South Africa)

The degree of early Archaean terrestrial differentiation into mantle and crust is long debated. A number of studies rely on bulk rock Hf and Nd isotope data to gain further insight. Here we present Hf-Nd data from two igneous basements suites of Barberton Mountain Land, namely a tonalite-trondhjemite-granodiorite (TTG) and granodiorite-granite-monzogranite (GGM) suite to further decipher crust formation and its timing in the Archaean. TTG show high initial ε(Hf) and ε(Nd) if corrected using their respective U/Pb zircon ages that can be interpreted in two ways: (i) early differentiation of bulk silicate Earth or (ii) overcorrection of these data caused by decoupling of zircon from the ‘zircon-free’ bulk rock due to metamorphic overprint. Indeed, regional metamorphism affected the early TTG ca. 250 Ma after their emplacement and disturbed their bulk rock Hf and Nd systematics. Correction of bulk rock Hf and Nd data to the age of metamorphism yields values between +0.9 and − 6.2 and from −1.3 to −4.3, respectively, thus indicating open-system behaviour. Lu-Hf and Sm-Nd mineral isochron ages of two TTG plutons are significantly younger than their corresponding U/Pb zircon age, but agree within uncertainty perfectly with external age constraints for the age of the metamorphic overprint. The same accounts for the 40Ar-39Ar systematics of the investigated plutons. Amphibole samples consist of a mixture of heterochemical generations that yield ages that are both older and younger than the metamorphic overprint at 3.2 Ga. The metamorphic minerals in each plutons provide a highly divergent age information from the coexisting zircon. Hence, the positive ε(Nd) and ε(Hf)-values that resulted from age-correction to the respective U/Pb zircon age are most probably over-corrected. Finally, if all data is age-corrected to the metamorphic overprint all samples agree with models for the Nd-Hf isotopic evolution in the mantle that do not require a large-scale early differentiation of Earth into enriched and depleted reservoirs. Mantle extraction ages (TDM) of TTG are interpreted as minimum ages for the generation of felsic Archaean crust whereas TDM of GGM are interpreted as maximum ages for the last major crust growth episode in the Barberton Mountain Land.

Understand growth episodes in Sub-Saharan Africa: Do exogenous shocks matters?

ABSTRACT This paper analyzes the effects of exogenous shocks on long-term growth. Additionally, it analyzes episodes of growth acceleration and reversal in 33 sub-Saharan Africa countries over the period 1980–2016. Fixed effects and the generalized method of moments are used to assess the effects of exogenous shocks on long-term growth. The results show that the terms of trade, remittances, and world demand improve long-term growth, while aid reduces it. Growth acceleration and reversal episodes are identified using an improved variant of the filter developed by Hausmann et al. (2005. “Growth Accelerations.” Journal of Economic Growth 10: 303–329). We further used a probit model to evaluate how exogenous shocks affect both growth episodes. Our results show that a favorable shock on the terms of trade, foreign aid and world demand increases the probability of acceleration, while an unfavorable shock on the terms of trade, remittances and world demand increases the probability of a growth reversal. Moreover, we find that economic and political reforms precede growth accelerations. Finally, the results show that growth reversals are associated with higher inflation, lower domestic credit, and civil wars.