Serving as “gateways”, some world cities tie their wider hinterlands to global networks. The article revisits gateway–hinterland relations against the backdrop of assessments that lead to opposed conclusions on the benefits and shortcomings of integration into the world economy. Referring to the oil and gas sector in Argentina and Ghana, it answers the question of how gateways interact with subordinate places and also uncovers obstacles to peripheral development. The author finds that Accra and Buenos Aires concentrate corporate control. Argentina's capital serves as a gateway for knowledge generation and logistics too. Opportunities for peripheral development in both countries are considerable, albeit largely limited to generic services. Besides a certain concentration of business activities in the gateway cities, more important challenges to peripheral development are typical for small and medium enterprises (insufficient finance and management capabilities, unawareness of business opportunities, and the like). They include rent seeking and subcontracting. The latter leaves local companies in a particularly weak position vis‐à‐vis lead firms. The author argues that while integration into the world economy allows for peripheral development, the corresponding outcomes may not meet everyone's expectations. Related expectations must, therefore, be more down‐to‐earth than overly optimistic statements frequently made by politicians.Weniger anzeigen
During foreign language acquisition neural representations of native language and foreign language assimilate. In the reading network, this assimilation leads to a shift from effortful processing to automated reading. Longitudinal studies can track this transition and reveal dynamics that might not become apparent in behavior. Here, we report results from a longitudinal functional magnetic resonance imaging (fMRI) study, which tracked functional changes in the reading network of beginning learners of Greek over one year. We deliberately chose Greek as foreign language that would have similar orthographic transparency but a different alphabet than the native language (Polish). fMRI scans with lexical and semantic decision tasks were performed at five different time points (every similar to 3 months). Classical language areas (the left inferior frontal gyrus, the left precentral gyrus, and the bilateral supplementary motor cortex), and cognitive control areas (left inferior parietal lobe and bilateral anterior cingulate cortex) showed stronger activation after the first months of instruction as compared to the activation before instruction. This pattern occured in both tasks. Task-related activity in the reading network remained constant throughout the remaining 6 months of learning and was also present in a follow-up scan 3 months after the end of the course. A similar pattern was demonstrated by the analysis of convergence between foreign and native languages occurring within the first months of learning. Additionally, in the lexical task, the extent of spatial overlap, between foreign and native language in Broca's area increased constantly from the beginning till the end of training. Our findings support the notion that reorganization of language networks is achieved after a relatively short time of foreign language instruction. We also demonstrate that cognitive control areas are recruited in foreign language reading at low proficiency levels. No apparent changes in the foreign or native reading network occur after the initial 3 months of learning. This suggests that task demand might be more important than proficiency in regulating the resources needed for efficient foreign language reading.Weniger anzeigen
A recent global meta-analysis reported a decrease in terrestrial but increase in freshwater insect abundance and biomass (van Klink et al., Science 368, p. 417). The authors suggested that water quality has been improving, thereby challenging recent reports documenting drastic global declines in freshwater biodiversity. We raise two major concerns with the meta-analysis and suggest that these account for the discrepancy with the declines reported elsewhere. First, total abundance and biomass alone are poor indicators of the status of freshwater insect assemblages, and the observed differences may well have been driven by the replacement of sensitive species with tolerant ones. Second, many of the datasets poorly represent global trends and reflect responses to local conditions or nonrandom site selection. We conclude that the results of the meta-analysis should not be considered indicative of an overall improvement in the condition of freshwater ecosystems.
This article is categorized under:
Water and Life > Conservation, Management, and AwarenessWeniger anzeigen
Aim: Phylogenetic diversification is a precursor to speciation, but the underlying patterns and processes are not well-studied in lichens. Here we investigate what factors drive diversification in two tropical, morphologically similar macrolichens that occupy a similar range but differ in altitudinal and habitat preferences, testing for isolation by distance (IBD), environment (IBE), and fragmentation (IBF).
Location: Neotropics, Hawaii, Macaronesia.
Taxon: Sticta andina, S. scabrosa (Peltigeraceae).
Methods: We analysed 395 specimens from 135 localities, using the fungal ITS barcoding marker to assess phylogenetic diversification, through maximum likelihood tree reconstruction, TCS haplotype networks, and Tajima's D. Mantel tests were employed to detect structure in genetic vs. geographic, environmental, and fragmentation distances. Habitat preferences were quantitatively assessed by statistical analysis of locality-based BIOclim variables.
Results: Sticta andina exhibited high phenotypic variation and reticulate phylogenetic diversity across its range, whereas the phenotypically uniform S. scabrosa contained two main haplotypes, one unique to Hawaii. Sticta andina is restricted to well-preserved andine forests and paramos, naturally fragmented habitats due to disruptive topology, whereas S. scabrosa thrives in lowland to lower montane zones in exposed or disturbed microsites, representing a continuous habitat. Sticta scabrosa showed IBD only across its full range (separating the Hawaiian population) but not within continental Central and South America, there exhibiting a negative Tajima's D. Sticta andina did not exhibit IBD but IBE at continental level and IBF in the northern Andes.
Main conclusions: Autecology, particularly preference for either low or high altitudes, indirectly drives phylogenetic diversification. Low diversification in the low altitude species, S. scabrosa, can be attributed to rapid expansion and effective gene flow across a more or less continuous niche due to disturbance tolerance. In contract, high diversification in the high altitude species, S. andina, can be explained by niche differentiation (IBE) and fragmentation (IBF) caused by the Andean uplift.Weniger anzeigen
The Anatomai, a lost work written by Aristotle, must have contained a collection of various drawings and figures of species as well as their organs. In his texts (mainly the Historia animalium), Aristotle is often referring to the drawings after the description of species. Our study applies the method of the comparative view (‘Vergleichendes Sehen’) to provide an access to and reconstruction of Aristotle’s lost illustrations based on his textual descriptions. As an example, we chose the treatment of the European lobster (Homarus gammarus L., 1758) in the Aristotelian corpus as a case study. First, we analyse the etymology of the Greek term astakós referring to the lobster and provide an overview on the putative synonyms. Second, we confront the textual basis of the description with several questions concerning the degree of abstraction, the relation between text and image, and the spatial orientation of the image. Finally, we present a step-by-step reconstruction of Aristotle’s illustrations of the lobster based on the various passages dealing with its anatomy in the text of the Historia animalium. The problems which arise by a confrontation of the textual basis with hypothetical images are discussed at a more general level. We conclude that this kind of a text-based image reconstruction is only possible if the object described by Aristotle is unambiguously identifiable and still visually accessible.Weniger anzeigen
Earthquake source parameters such as seismic stress drop and corner frequency are observed to vary widely, leading to persistent discussion on potential scaling of stress drop and event size. Physical mechanisms that govern stress drop variations arc difficult to evaluate in nature and are more readily studied in controlled laboratory experiments. We perform two stick-slip experiments on fractured (rough) and cut (smooth) Westerly granite samples to explore fault roughness effects on acoustic emission (AE) source parameters. We separate large stick-slip events that generally saturate the seismic recording system from populations of smaller AE events which are sensitive to fault stresses prior to slip. AE event populations show many similarities to natural seismicity and may be interpreted as laboratory equivalent of natural microseismic events. We then compare the temporal evolution of mechanical data such as measured stress release during slip to temporal changes in stress drops derived from Alis using the spectral ratio technique. We report on two primary observations: (1) In contrast to most case studies for natural earthquakes, we observe a strong increase in seismic stress drop with AE size. (2) The scaling of stress drop with magnitude is governed by fault roughness, whereby the rough fault shows a more rapid increase of the stress drop magnitude relation with progressing large stick-slip events than the smooth fault. The overall range of AE sizes on the rough surface is influenced by both the average grain size and the width of the fault core. The magnitudes of the smallest AE events on smooth faults may also be governed by grain size. However, AEs significantly grow beyond peak roughness and the width of the fault core. Our laboratory tests highlight that source parameters vary substantially in the presence of fault zone heterogeneity (i.e. roughness and narrow grain size distribution), which may affect seismic energy partitioning and static stress drops of small and large AE events.Weniger anzeigen
Model reduction of large Markov chains is an essential step in a wide array of techniques for understanding complex systems and for efficiently learning structures from high-dimensional data. We present a novel aggregation algorithm for compressing such chains that exploits a specific low rank structure in the transition matrix which, e.g., is present in metastable systems, among others. It enables the recovery of the aggregates from a vastly undersampled transition matrix which in practical applications may gain a speedup of several orders of magnitude over methods that require the full transition matrix. Moreover, we show that the new technique is robust under perturbation of the transition matrix. The practical applicability of the new method is demonstrated by identifying a reduced model for the large-scale traffic flow patterns from real-world taxi trip data.Weniger anzeigen
We use the terahertz (THz) emission spectroscopy to study femtosecond photocurrent dynamics in the prototypical 2D semiconductor, transition metal dichalcogenide MoSe2. We identify several distinct mechanisms producing THz radiation in response to an ultrashort (30 fs) optical excitation in a bilayer (BL) and a multilayer (ML) sample. In the ML, the THz radiation is generated at a picosecond timescale by out-of-plane currents due to the drift of photoexcited charge carriers in the surface electric field. The BL emission is generated by an in-plane shift current. Finally, we observe oscillations at about 23 THz in the emission from the BL sample. We attribute the oscillations to quantum beats between two excitonic states with energetic separation of similar to 100 meV.Weniger anzeigen
A well-known conjecture, often attributed to Ryser, states that the cover number of an r-partite r-uniform hypergraph is at most r - 1 times larger than its matching number. Despite considerable effort, particularly in the intersecting case, this conjecture remains wide open, motivating the pursuit of variants of the original conjecture. Recently, Bustamante and Stein and, independently, Kiraly and Tothmeresz considered the problem under the assumption that the hypergraph is t-intersecting, conjecturing that the cover number tau(H) of such a hypergraph His at most r-t. In these papers, it was proven that the conjecture is true for r <= 4t - 1, but also that it need not be sharp; when r = 5 and t = 2, one has tau(H) = 2.
We extend these results in two directions. First, for all t = 2 and r <= 3t - 1, we prove a tight upper bound on the cover number of these hypergraphs, showing that they in fact satisfy tau(H) <= left perpendicular(r- t)/2 right perpendicular + 1. Second, we extend the range of tfor which the conjecture is known to be true, showing that it holds for all r <= 36/7t-5. We also introduce several related variations on this theme. As a consequence of our tight bounds, we resolve the problem for k-wise t-intersecting hypergraphs, for all k >= 3 and t >= 1. We further give bounds on the cover numbers of strictly t-intersecting hypergraphs and the s-cover numbers of t-intersecting hypergraphs.Weniger anzeigen
Background With intensive use of anthelmintic drugs in recent decades, anthelmintic resistance (AR) in horse nematodes is becoming a growing issue in many countries. However, there is little available information about the parasites, treatment practices or AR in the horse population in Lithuania. The aim of this study was to assess the current situation of AR on horse farms in Lithuania. The study was conducted in 25 stables on horses with a strongyle faecal egg count (FEC) of >= 200 eggs per gram. A faecal egg count reduction test (FECRT) was performed on each farm after administration of ivermectin (IVM) or pyrantel (PYR). Results The efficacy of IVM was comparatively high, with 98.8% of 250 horses having a zero egg count 14 days after treatment. Two conditions were used to interpret the FECRT results for PYR: firstly, resistance was determined when FECR was < 90% and the lower 95% confidence interval (LCL) was < 80%, and secondly when in addition the upper confidence level (UCL) was < 95%. Under the first condition, resistance against PYR was found in five stables (25% of all tested herds), while when considering the UCL as well, resistance was only detected in two stables (8%). The FEC showed a significant (P < 0.01) difference between the treatment and control groups. Only cyathostomin larvae were detected in larval cultures derived from strongyle-positive faecal samples collected 14 days after treatment of a test group with PYR. Conclusions This in vivo study showed that PYR resistance is prevalent on horse farms in Lithuania, while the efficacy of IVM still appears to be unaffected. However, further studies of ivermectin resistance are needed. These findings should guide the implementation of more sustainable management of strongyle infections in horses in Lithuania.Weniger anzeigen
The history of segregation is usually concentrating on modern racial forms of it, in colonial settings or in large urban conglomerates. Mathematical definitions of segregation refer to the ratio between the type of segregated element (e.g. Blacks) in a given larger area and its sub-area. We are suggesting that pre-modern as well as postcolonial forms of segregation are far less determined by this space/race-alignment. For a long-term history of segregation concerned with many other dominating themes and objects of segregation (such as religion, non-racist ethnicity), we propose to concentrate on the fluid cognitive dimension of what segregation is, close distance: ‘distance’ can refer to physical space, but it is also far more open to cognitive forms of distance. ‘Closeness’ aims to draw attention to the fact that both the processing and enacting of separation and difference, from the early to the late period of colonialization, may have nothing to do with how far away or how close together people actually live. Ignorance and ignoring are one of the most important elements of this epistemic core of segregational behaviour and of what creates close distance in societies.Weniger anzeigen
L’ambito della storia della sicurezza è cresciuto rapidamente negli anni recenti – nonostante appaia ancora quello meno indagato all’interno dell’ampio contesto interdisciplinare degli studi sulla sicurezza. L’articolo cerca di disegnare un schizzo dello stato dell’arte, sottolineando tre aspetti: in primo luogo, una (tuttora assente) storia della sicurezza di età rinascimentale – la storia dell’iniziale concetto di sicurezza collettiva transterritoriale sviluppato nell’ambito del sistema degli Stati italiani del Quattrocento; in secondo luogo, lo sviluppo della sicurezza come principio guida dell’amministrazione interna allo Stato soprattutto nell’Europa continentale nei secoli XVII e XVIII; in terzo luogo, le sfide di una storia della sicurezza ambientale come storia delle relazioni transterritoriali e transnazionali tra economie politiche, natura e volontà di fornire sicurezza (a esseri umani, Stati, imperi).Weniger anzeigen
Das „Modell Deutschland“ hat sich in der Vergangenheit als überaus stabil erwiesen. Gleichwohl steht aktuell die Automobilindustrie, die zentrale Branche des deutschen Kapitalismusmodells, vor tief greifenden Transformationen, deren genaue Konturen sich jedoch nur erahnen lassen. Der Beitrag diskutiert aus einer regulationstheoretischen Perspektive die sich abzeichnenden Veränderungen und argumentiert, dass die internationale Einbettung des „Modell Deutschland“ nicht nur im Hinblick auf die aktuelle Doppelkrise des liberalen Kapitalismus, sondern auch im Hinblick auf die materiell-stoffliche Dimension des deutschen Exportmodells von zentraler Bedeutung ist. Darüber hinaus bedarf es eines präziseren Verständnisses der Rekonfiguration der automobilen Wertschöpfungsketten, die sich durch Digitalisierung und neue Mobilitätsdienstleistungen sowie eine Veränderung der Rohstoffbedarfe und industrieller Fertigungsprozesse im Zuge der Elektrifizierung des Antriebsstrangs verändern und sowohl das Lohnverhältnis als auch die Unternehmensformen stark beeinflussen.Weniger anzeigen
Die COVID-19-Pandemie perturbiert alle gesellschaftlichen Sektoren und führt eindrücklich vor Augen, dass sie miteinander verwoben sind. Dieser Prozess lässt sich gut als Verhältnis von Resilienz und Vulnerabilität der Teilsysteme begreifen. Aus aktuellen human ökologischen Diskursen mit systemtheoretischem Fokus leiten wir zwei Rahmenmodel le zum Struktur- und Prozessverständnis der Pandemie und ihrer Effekte ab und stellen sie hier zur Diskussion.Weniger anzeigen
Due to growing global socio-economic and environmental challenges (population ageing, climate change, society polarization, etc.), there is a revaluation of a position and role of innovations in overcoming threats to social development in the modern world. Researchers note a shift in the innovation paradigm toward social innovation, since it is assumed that it is not possible to achieve a drastic improvement of the situation solely through technological innovations. At the same time, many existing problems cannot be solved with efforts of a single actor - intersectoral cooperation becomes a necessity. This aspect is of key importance for development of social innovation. The purpose of the study was to analyze development of social innovations in the Russian Federation based on an actor approach, which involves an overview of this phenomenon through the prism of activities of various entities and their interaction. General scientific methods were used in the study: discourse analysis, generalization, comparison, etc. Essential foundations and the role of social innovations in solving current society's problems are presented. Using the example of government structures, big business, and civil society, the authors explore the features of social innovation development in Russia. It is shown that development of social innovations depends on their interpretation in public discourse, involvement in strategies of various actors, and intersectoral cooperation in the innovation process. In conclusion, the prospects for development of studied phenomenon are determined within identified trends and the specifics of interconnections between designated actors. The results obtained may be used not only as an empirical basis for further research, but they may also represent practical significance in development of specific management decisions in this area.Weniger anzeigen
Light is important for plants as an energy source and a developmental signal, but it can also cause stress to plants and modulates responses to stress. Excess and fluctuating light result in photoinhibition and reactive oxygen species (ROS) accumulation around photosystems II and I, respectively. Ultraviolet light causes photodamage to DNA and a prolongation of the light period initiates the photoperiod stress syndrome. Changes in light quality and quantity, as well as in light duration are also key factors impacting the outcome of diverse abiotic and biotic stresses. Short day or shady environments enhance thermotolerance and increase cold acclimation. Similarly, shade conditions improve drought stress tolerance in plants. Additionally, the light environment affects the plants' responses to biotic intruders, such as pathogens or insect herbivores, often reducing growth‐defence trade‐offs. Understanding how plants use light information to modulate stress responses will support breeding strategies to enhance crop stress resilience. This review summarizes the effect of light as a stressor and the impact of the light environment on abiotic and biotic stress responses. There is a special focus on the role of the different light receptors and the crosstalk between light signalling and stress response pathways.Weniger anzeigen
Karst aquifers are abundant, but vulnerable water resources. Therefore, a deeper understanding of possible mechanisms that determine the properties of karst springs is crucial. In this work, we present an example of Unica Spring and Malni Spring, the two main outlets of a large karst system in the Notranjska karst region, Slovenia. Although the two springs share same catchment area, the flow distribution between them shows an interesting behaviour: At low-flow conditions Malni Spring is the main outlet, while Unica spring receives almost no water. During high water events, discharge of Malni Spring stays limited and Unica Spring becomes the main outlet. We relate these observations to the local geometry of the channels and breakdowns in the remote part of the Planinska Jama (Planina Cave), called Mysterious Lake. There, waters from Rakov kocjan and Javorniki aquifer merge and further diverge to both springs. At low water conditions, the outflow towards the Unica Spring is restricted by the breakdown, so that most of the inflow is directed towards the Malni Spring. With increasing recharge, the level in Mysterious Lake rises until the water starts to flow over the breakdown along a system of large channels (Rak Branch of Planinska Jama) to the Unica Spring. The breakdown level keeps the hydraulic head and the flow towards Malni Spring limited. To verify this scenario, a hydraulic conduit model was made based on the known and predicted channels, and inflows calculated from the historical data of discharge measurements at related springs and ponors. An inversion procedure was used to obtain a satisfactory fit to the observed discharge data and to constrain the selected model parameters. The model accurately reproduced the observed discharge behaviour under low- and high-flow conditions.Weniger anzeigen
The sharing economy has brought new opportunities to the logistics industry, which has created an emerging trend known as crowd logistics. Implementing this mode offers a basis for more sustainable urban logistics, but there is limited research on what leads enterprises to adopt crowd logistics. Based on the technology-organization-environment (TOE) theoretical model, this paper developed a model to study the influencing factors of enterprises' willingness to implement crowd logistics. The data were collected through questionnaire surveys, SPSS and AMOS were used for data analysis. The empirical results showed that the relative advantage, absorptive capacity, market environment, and external motivations have significant positive impact on the company's willingness to implement crowd logistics, while complexity and resources have no significant impact. Crowd logistics offers an important route to more sustainable urban logistics. Logistics enterprises should take measured steps when implementing crowd logistics, improve their absorptive capacity, and take necessary precautions towards minimizing the risks of crowd logistics.Weniger anzeigen
The 1s(-2) Auger hypersatellite spectrum of argon is studied experimentally and theoretically. In total, three transitions to the final states 1s(-1)2p(-2)(S-2(e),D-2(e)) and 1s(-1)2s(-1)(S-1)2p(-1)(P-2(o)) are experimentally observed. The lifetime broadening of the 1s(-2) -> 1s(-1)2p(-2)(S-2(e),D-2(e)) states is determined to be 2.1(4) eV. For the used photon energy of h nu = 7500 eV a KK/K ionisation ratio of 2.5(3) x 10(-4) is derived. Generally, a good agreement between the experimental and present theoretical energy positions, linewidths, and intensities is obtained.Weniger anzeigen