Thursday, June 17, 2021

21ST CENTURY ALCHEMY

Tailored laser fields reveal properties of transparent crystals

Research team led by the University of Göttingen investigates surface magnetisation

UNIVERSITY OF GÖTTINGEN

Research News

IMAGE

IMAGE: IMAGE OF QUARTZ CRYSTALS UNDER ILLUMINATION WITH STRONG LASER FIELDS OF DIFFERENT COLOURED LIGHT (RED AND BLUE), AND BOTH COLOURS ADDED TOGETHER (MIDDLE). view more 

CREDIT: MURAT SIVIS

The surface of a material often has properties that are very different from the properties within the material. For example, a non-conducting crystal, which actually exhibits no magnetism, can show magnetisation restricted to its surface because of the way the atoms are arranged there. These distinct properties at interfaces and surfaces of materials often play a key role in the development of new functional components such as optoelectronic chips or sensors and are therefore subject to extensive research. An international research team from the University of Göttingen, the Max Planck Institute for Biophysical Chemistry Göttingen and the National Research Council Canada has now succeeded in investigating the surfaces of transparent crystals using powerful irradiation from lasers. The results of the study were published in the journal Nature Communications.

The researchers describe their method, which relies purely on light, to determine electrical and magnetic properties on surfaces. This new method could play an important role in the investigation of transparent, non-conductive materials, as established methods using electrons often experience experimental limitations due to low conductivity, among other difficulties. The use of light helps get around these limitations: when light rays hit a material surface, for example a glass pane, they are reflected at the interface, refracted and absorbed into the material. These effects, which can be observed in everyday life, are the result of the interaction of the weak light field with the atoms and electrons of the irradiated material. In the case of stronger light fields, which are achieved with lasers, further effects occur, which can, for example, generate higher light frequencies - known as high harmonic radiation. These effects are often dependent on the direction of oscillation of the light field relative to the atomic arrangement in the material.

"We take advantage of this dependence when generating high harmonic radiation to gain insights into the properties at and near the surface of transparent materials," says first author and PhD student Tobias Heinrich from the Faculty of Physics at Göttingen University. "The light field we use is composed of two laser pulses rotating in opposite directions at two different frequencies, and this results in a cloverleaf-shaped symmetrical field." These tailor-made light fields can be adapted to the atomic arrangement of the material to control the generation of the high harmonics.

"We show that this control can be used to study magnetisation at the surface of magnesium oxide," explains Dr Murat Sivis, the study lead. Depending on the direction of rotation of the light field - also called chirality - the generated ultraviolet light is absorbed to different degrees at the interface. "For various materials that do not actually exhibit magnetisation or electrical conductivity, these properties at the surface have been predicted in theory," Sivis said. "In our study, we show that it is now possible to investigate such phenomena using just optical methods, probably even at very short time scales." The researchers also hope to gain new insights into the electronic properties of other chiral materials, as the study shows using the example of the helical crystal structure of quartz. The sensitivity to chiral phenomena on surfaces could potentially open up new opportunities for research into innovative functional materials.


CAPTION

Image of a quartz crystal illuminated by light made up of two colours.

CREDIT

Murat Sivis




CAPTION

Artist's impression of the illumination of a magnesium oxide crystal lattice with strong triangular symmetrical laser fields

CREDIT

Murat Sivis

Originalveröffentlichung: Tobias Heinrich et al. „Chiral high-harmonic generation and spectroscopy on solid surfaces using polarization-tailored strong fields". Nature Communications (2021). 

Doi: 10.1038/s41467-021-239

'First empirical evidence of an identity-related societal cleavage'

CLUSTER OF EXCELLENCE "RELIGION AND POLITICS"

Research News

An international survey by the University of Münster's Cluster of Excellence "Religion and Politics" provides the first empirical evidence of an identity-related political cleavage of European societies that has resulted in the emergence of two entrenched camps of substantial size. "We see two distinct groups with opposing positions, which we call 'Defenders' and 'Explorers'", says psychologist Mitja Back, spokesperson of the interdisciplinary research team that conducted the most comprehensive survey of identity conflicts in Europe to date. "Who belongs to our country, who threatens whom, who is disadvantaged? Across all such questions of identity, the initial analyses of the survey reveal a new line of conflict between the two groups, which have almost diametrically opposite opinions. In debates over identity, these opinions have hardened into seemingly irreconcilable conflicts. The study could open up new avenues to tackle these conflicts".

The two camps together account for a significant proportion of citizens in all countries: more than one-third in Germany (Fig. 3.1) and almost three-quarters in Poland (Fig. 3.4). In liberal democratic states like Germany, the proportion of 'Defenders' is 20% and that of 'Explorers', 14%. In France and Sweden, 14% and 29% 'Defenders', and 11% and 15% 'Explorers', respectively, were observed. In a semi-authoritarian country like Poland, where according to the researchers the government provides populist support to the 'Defenders' opinions, the proportion of both groups combined is 72%. "This shows how much the conflict can escalate in a country: the polarized positions can grow to form the majority", says Mitja Back. "The degree to which a population becomes polarized and how far feelings of threat and narrow ideas of identity also entail feelings of disadvantage and mistrust therefore vary depending on the political system. This suggests that identity conflicts are open to political influence".

Who are 'Explorers' and 'Defenders'?

5,011 respondents in Germany, France, Poland and Sweden took part in the survey, which the Cluster of Excellence conducted with "Kantar Deutschland" at the end of 2020. Its authors are the sociologists Detlef Pollack and Olaf Müller, the psychologists Mitja Back and Gerald Echterhoff, and the political scientist Bernd Schlipphak. Their Working Report, "Of Defenders and Explorers: An identity conflict over belonging and threat" (http://go.wwu.de/izpgb), provides initial results. Drawing on the detailed results on more than 20 questions examined, they used cluster analyses to form groups comprising people with very similar attitudes and displaying strong differences one from the other. This yielded the patterns of 'Explorers' and 'Defenders' across all questions.

In all countries, the 'Defender' group largely endorse a narrow definition of who belongs to their country, with only those belonging who were born in the country, have ancestors of the ethno-national majority, and/or belong to the dominant religion. They therefore defend traditional criteria such as ethnic and religious homogeneity. At the same time, 'Defenders' feel rather threatened by foreigners such as Muslims and refugees, and consider themselves rather disadvantaged. They are also more dissatisfied with democracy and more distrustful of political institutions.

The 'Explorer' group, on the other hand, reject a narrow definition of belonging based on ethno-religious criteria. Its members do not feel threatened by foreigners, but instead see immigration and growing diversity as an opportunity, and they also advocate a society with many notions of life oriented towards equality. They see themselves as being well represented by the political system, are more satisfied with democracy, and are more likely to trust political institutions. In semi-authoritarian Poland, however, where the government provides populist support to 'Defenders' positions on ethno-religious homogeneity and protection against foreigners, the 'Explorers' also feel disadvantaged and are dissatisfied with democracy and government.

The two groups also differ strongly in cultural, religious, psychological and social terms (Figs. 3.6 and 3.7), with 'Defenders' in all countries being far more attached to home and religious than 'Explorers'. The former also have a stronger preference for social hierarchies and trust other people less, while the reverse is true of the latter. 'Explorers' also tend to be quite young, highly educated, more likely to live in a city, and less likely to be affected by socio-economic hardship. Except in Poland, 'Defenders' are more likely than 'Explorers' to be found among the elderly and the low educated. They tend to live in rural areas and, again with the exception of Poland, consider themselves to have a lower social status.

Political effects and recommendations

The cultural conflict also has strong political effects: 'Defenders' favour populist parties and believe much more in the concept of a "strong leader"; they are also prone to conspiracy theories and advocate elements of direct democracy. 'Explorers' hold diametrically opposed views. For example, 26% of 'Defenders' in Germany and 57% in Poland are likely to vote for a populist party (Fig. 6.6), while 'Explorers' tend not to.

According to the researchers, this can represent fundamentally different concepts of politics: 'Defenders' favour concepts more in line with anti-pluralist ideas that claim that political regulations should express a single popular will; 'Explorers', in contrast, share attitudes more compatible with pluralist ideas that claim that politics is a process of negotiation and compromise between different interests. Mitja Back: "A person's positioning in the conflict as 'Explorer' or 'Defender' can have a strong impact on the form of democracy desired. Cultural conflicts over identity have therefore become very entrenched politically, and now structure the population's social and political views to a significant extent".

By linking their results to other insights from current research, the authors see the polarized positions as being rooted in fundamental and rather stable psychological needs of varying strength, such as security and stability ('Defenders'), or openness and change ('Explorers'). According to the report, this implies that societies are always composed of a mixture of 'Explorers' and 'Defenders'. In contrast to more material conflicts, the identity conflict is therefore more difficult to negotiate, and especially so when ideas of identity are framed in religious or fundamentalist terms. Identity conflict is also exacerbated by the effects of globalization, such as migration, increasingly supranational instead of national policies, and crises such as the financial crisis and the Covid 19 pandemic. "This makes questions of identity - who belongs to the country, or who triggers feelings of threat - all the more urgent".

The researchers therefore urge politicians to refrain from taking one of the two sides. Neither in liberal democracies nor in authoritarian countries has this led to movement in entrenched conflicts, as at least one group always feels excluded. Rather, it is important to take the underlying psychological needs on both sides seriously, and to understand them as social resources, while tracing the sometimes widely divergent demands of both groups back to their functional core. "In this way, it is possible to filter out which positions are not acceptable to each group, and which are open to negotiation. Only by doing so can we find a basis for compromise that currently seems impossible, as well as space for dialogue without one side devaluing the other". (vvm/sca)

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Detailed results behind the core findings: a selection

The researchers back up their core findings on the groups of 'Defenders' and 'Explorers' with detailed results for individual countries and for the factors that determine the identity conflict.

Results underline that 'Defenders' and 'Explorers' occupy polarized positions. In Germany, for example, 61% of 'Defenders' advocate a narrow definition of ethno-religious belonging; 49% feel threatened by Muslims, and 55%, by refugees; 45% feel culturally disadvantaged; and only 21% are satisfied with democracy, with only 11% trusting the government and parliament. In contrast, in the group of 'Explorers', less than 15% have a narrow, ethno-religious definition of belonging, none feel threatened or marginalized, and a large majority (93%) are satisfied with democracy and trust political institutions (the federal government, 100%; the EU, 99%). Similar results were obtained for France and Sweden.

Poland is an exception. In this semi-authoritarian country, where the government supports 'Defenders' positions such as the desire for ethno-religious homogeneity and protection against foreigners, 29% of 'Defenders' and 49% of 'Explorers' feel politically marginalized. The latter are also dissatisfied with democracy in the country and distrust the government, whereas they have a high level of trust in the EU (74%). 'Defenders' in Poland are satisfied with democracy in the country (57%), and have a high level of trust in the government and parliament (72%), but far less trust in the EU (32%). Society is much more divided than it is in other countries, with 'Explorers' and 'Defenders' making up 72% of the population in Poland. "The example of Poland shows that the political system and political communication influence how divided a society is, and how much each group feels marginalized and accepts democratic institutions".

In Germany, the two groups differ in socio-cultural, religious and psychological terms as follows: in the 'Defender' group, 33% have a high level of religiosity, 52% feel more attached to home than to the world, 34% believe in social hierarchies, and 31% are sceptical of other people. In contrast, 24% of 'Explorers' are strongly religious, 31% have a strong attachment to home, 4% believe in social hierarchies, and 3% have little trust in people. The other countries show similar tendencies here. (vvm/sca)

Survey methods

The Working Report "Of Defenders and Explorers: An identity conflict over belonging and threat" presents results of a survey conducted at the University of Münster's Cluster of Excellence "Religion and Politics" as part of the project "Threat perceptions, feelings of belonging, acceptance of democratic rule: A new religiously shaded line of conflict in Europe?" Its authors are the sociologists Detlef Pollack and Olaf Müller, the psychologists Mitja Back and Gerald Echterhoff, and the political scientist Bernd Schlipphak.

  • Survey fielded via random sampling in four European countries (Germany, France, Poland and Sweden) in line with the highest methodological standards

  • Survey period: 9 November to 18 December 2020
    • 5,011 participants (in Germany, 1,402; 506 of whom from the five federal states in the east and Berlin; in France, 1,208; in Poland, 1,200; in Sweden, 1,201)
    • CATI procedure (CATI: Computer Assisted Telephone Interviewing)
    • Consideration of landline and mobile phone numbers (dual-frame sampling design)
    • Conducted by the market research company "Kantar Deutschland" (Berlin)

Participants answered questions on ten themes (see overview below), initially on the following four factors that are central to identity conflict: definitions of national belonging, feelings of threat, feelings of disadvantage, and perception of political representation and governance. Added to these were cultural, religious and psychological factors, as well as social characteristics such as age, gender, education and region, which at the end were weighted to avoid bias. Most factors are composed of several individual questions (items).

The researchers applied the statistical instrument of cluster analysis to the detailed results on all factors examined. Cluster analyses enable researchers to find out whether the landscape of opinions shown by the survey can yield distinct social groups in the identity conflict. The existence of such distinct social groups has been discussed, but not yet empirically verified. The study demonstrated two consistent groups across all factors and countries, whose members show very similar attitudes, and who as groups show strong differences from each other. This resulted in the pattern of 'Explorers' and 'Defenders'. (sca/vvm)

Structure of the survey

A) Factors determining identity conflict

1) Definitions of national belonging (such as questions about an ethno-religious definition of belonging)

Example question: "Some people think that the following things are important to be a real German. Others think that they are not important. How do you rate these things? In your opinion, to be a real German, is it very important, quite important, not very important, or not important at all that a person ...

  • has been born in Germany?
  • has lived in Germany for most of her life?
  • is a Christian?
  • has German ancestors?"

2) Threat perceptions (e.g. questions about feelings of threat from Muslims and refugees, since these minority groups most often appear in discourses of belonging)

Example questions (agree/disagree): "Muslims threaten our way of life and our values in Germany", "The values and beliefs of Muslims are not compatible with the general values and beliefs in Germany", "Muslims threaten the economic situation in Germany", "Muslims living here threaten public safety in Germany", "Because of Muslims, there are more acts of violence in Germany"

3) Feelings of disadvantage (such as questions about economic, political and cultural recognition or marginalization)

Example questions (agree/disagree): "The work of people like me is not recognized enough in society", "No matter how hard we work, people like me are not appreciated", "The problems of people like me are unimportant to most politicians", "Most politicians do not care what people like me think", "The values of people like me have are becoming less and less important in society", "The customs, traditions, and manners of people like me are less and less appreciated"

4) Political representation and governance (such as questions about satisfaction with democracy, and trust in the national government and the European Union)

Example questions (agree/disagree): "All in all, I am satisfied with how democracy works in Germany", "For the following public institutions or groups of people, please indicate how much you personally trust each of them - Bundestag, federal government", "For the following public institutions or groups of people, please indicate how much you personally trust each of them - the EU"

B) Social, cultural, religious, psychological and political factors

5) Socio-demographic characteristics (age, level of education, residential area)

6) Assessments of the socio-economic situation (e.g. questions about where respondents would position themselves on an imaginary social ladder, or their assessment of the economic situation of their own country)

7) Socio-cultural factors and attitudes (e.g. questions about contacts with Muslims, degree of attachment to home, and national pride)

8) Personality traits and social attitudes (e.g. questions about trust in people in general, belief in social hierarchies, and right-wing authoritarianism)

9) Religion and religiosity (e.g. questions about religious affiliation, church-based religious practice, and fundamentalist positions)

10) (Desired) models of political governance (e.g. questions about approval of liberal democracy and of populism, and about the conspiracy mindset)

Example questions (agree/disagree): "Democracy is a good form of government", "There should be a strong leader who does not have to worry about parliament and elections", "The country is ruled by a few large interest groups looking out for themselves", "The will of the people should be decisive in this country's politics", "There are many important things happening in the world that are controlled by influential groups without the public's knowledge" (sca/vvm)


CAPTION

Psychologist Prof. Dr. Mitja Back, Speaker of the research team.

CREDIT

Cluster of Excellence

Wild chimpanzee orphans recover from the stress of losing their mother

Long-term study shows that maternal loss is stressful for immature orphan wild chimpanzees -- but only for the first couple of years

MAX PLANCK INSTITUTE FOR EVOLUTIONARY ANTHROPOLOGY

Research News

 NEWS RELEASE 

The death of a mother is a traumatic event for immature offspring in species in which mothers provide prolonged maternal care, such as in long-lived mammals, including humans. Orphan mammals die earlier and have less offspring compared with non-orphans, but how these losses arise remains under debate. Clinical studies on humans and captive studies on animals show that infants whose mothers die when they are young are exposed to chronic stress throughout their lives. However, such chronic stress, which has deleterious consequences on health, can be reduced or even cancelled if human orphans are placed in foster families young enough. How stressed orphans are in the wild and whether wild animal orphans are exposed to chronic stress over decades like in humans, remains unknown, especially in species where infants are dependent on their mother for at least the first 10 years of life, like in chimpanzees.

Young chimpanzees who lose their mother are highly stressed

Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig and the Institute of Cognitive Sciences, CNRS in Lyon investigated over 19 years the short- and long-term effects of maternal loss on the stress of orphan wild chimpanzees. Their study shows that immature orphan chimpanzees are highly stressed, especially when they were orphaned at a young age. However, orphans who lost their mother more than two years previously, or were now adult, were not more stressed than other individuals whose mother did not die.

"Our study provides an important test of how relevant theories are that try to explain the impact of early life adversity when they are drawn from human clinical studies. In particular we wanted to know how relevant they are for wild long-lived primates whose young, as in humans, are dependent on their mother for over a decade", says the first author Cédric Girard-Buttoz.

Adult chimpanzees often care for or even adopt orphans

"Our findings nicely contrast to human studies and show that young orphan chimpanzees recover over time from the initially stressful loss of their mother. Taï chimpanzees often care for or adopt orphans. They may carry orphans, share their food and their nest at night with them, or protect them from aggression. Whether orphan chimpanzees show stress recovery because of the support offered by other chimpanzees remains to be studied", Roman Wittig, a senior author and head of the Taï Chimpanzee Project points out.

"The stress experienced by orphan chimpanzees compared with non-orphans does not directly explain their shorter lives and fewer offspring, but may have an effect on other important factors such as growth during critical periods in development", says senior author Catherine Crockford. "In long-lived species where offspring stay with their mothers for many years, the next step is to unpick what mothers provide offspring that helps them get ahead of orphans. It might be that a mothers' presence results in nutritional gains or social advantages, such as providing buffering against aggression from others, or a mix of the two".

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Original publication:

Cédric Girard-Buttoz, Patrick J Tkaczynski, Liran Samuni, Pawel Fedurek, Cristina Gomes, Therese Löhrich, Virgile Manin, Anna Preis, Prince F Valé, Tobias Deschner, Roman M Wittig, Catherine Crockford
Early maternal loss leads to short- but not long-term effects on diurnal cortisol slopes in wild chimpanzees
eLife, 16 June 2021

POSTMODERN CAPITALI$M

Financial networks: A new discipline to interpret crises and green transition

UNIVERSITÀ CA' FOSCARI VENEZIA

Research News

Modelling the financial system as a network is a precondition to understanding and managing challenges of great relevance for society, including the containment of financial crises and the transition to a low-carbon economy.

Financial Networks is the scientific discipline that deals with these issues. An article published in the scientific journal Nature Review Physics carries out the first comprehensive review of this exciting interdisciplinary field. By covering over 250 studies across domains, the paper is also a call for researchers in all scientific disciplines to consider the insights from the financial network models, because of their implications for citizens, public agencies and governments. Professor Guido Caldarelli from Ca' Foscari University of Venice coordinated the study, which involved Marco Bardoscia, a researcher from the Bank of England, as the first author.

"Traditional economic models describe the financial system either as a macroeconomic aggregate or, in contrast, as a collection of microeconomic actors in isolation. - Stefano Battiston, co-author and professor of Finance, at the Department of Economics of Ca' Foscari University of Venice, explains. - Both approaches are not equipped to describe those phenomena that emerge at the intermediate scale, because of interconnectedness. Financial actors are connected (directly and indirectly) via contracts, markets and institutions. These phenomena include, in particular, the propagation of risk along a chain of contracts (financial contagion), as well as the collective behaviour of investors when they stamped to get rid of assets suddenly deemed as riskier than expected (fire-sales)".

The discipline of financial networks has thus filled important scientific gaps. The importance of financial networks is widely recognised today. Many central banks use network models to carry out stress-tests. The highest financial authorities both in the US and in the EU follow macroprudential policies that recognise the key role of the interconnectedness of the financial system. Indeed, network effects played a key role in the 2007-2008 financial crisis, with an impact persisting for a decade, and they played a role also in the Covid crisis.

"There is something fascinating and special about the field of financial networks. - Guido Caldarelli, a co-author of the study and professor of Physics at the Department of Molecular Sciences and Nanosystems of Ca' Foscari, adds. - Questions that pertain to finance and economics are addressed by modelling financial actors as nodes and financial contracts as links in a network. For instance, the question of how to preserve the stability of the financial system is addressed by looking at the interplay between the network structure (i.e. the topology), the characteristics of individual nodes (the balance sheets) and the dynamic process on the nodes (the propagation of financial losses)".

This approach owes a great deal to the field of statistical physics which has been historically devoted to the challenge of explaining the emergence of macroscopic behaviour of a system from the microscopic properties of the individual entities. However, in financial networks, there are additional distinct features that raise the stakes of the challenge. The entities of the system are not particles, but agents that form expectations about the future evolution of the network and even about the policy maker's attempt to regulate the system. This leads to new scientific questions in terms of the mathematical equations that can describe such reflexivity.

"In the near future, Financial Networks will address several exciting scientific challenges - Guido Caldarelli foresees - For example, modern financial systems are composed of multiple interacting networks because of agents acting on multiple markets with different instruments. Further, modelling the financial system poses big data issues as transactions generate Terabytes of information every day. Moreover, the interaction of the financial system with the real economy is a feedback loop and still not well-understood".

One avenue of research of particular interest for Ca' Foscari's researchers is the application of financial networks in the area of sustainable finance. The European Union has set the goal to become net carbon neutral by 2050. The transition to a carbon-neutral economy will avoid the most adverse impact of global warming on current and future generations.

It will also ensure the competitiveness of the EU and of Italy. Indeed, an early transition brings opportunities. In contrast, a transition that would be first delayed and then would occur in a sudden way would bring higher risks, possibly systemic. In fact, financial institutions have large exposures to economic activities that are affected by climate policies. Therefore, financial network models are key to understanding how to facilitate the transition and mitigate climate-related financial risks.

In addition, the article demonstrates the relevance of financial networks not only for research but also for practitioners in financial authorities and in the industry. "Today, having competencies in Financial Networks gives a competitive advantage to prospective students graduating both at a Master's and PhD level. - professor Battiston adds, - Courses in this field will enrich the curricula of study not only in physics but also in economics and finance. This could apply also to future executive education programmes".

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Anthropogenic forcing increases drought risks in Southeast Asia

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

Research News

IMAGE

IMAGE: CHANGES IN EXTREME DROUGHT (A) OCCURRENCE (MONTH YEAR-1) AND (B) AFFECTED AREA FRACTION (%) OVER THE SOUTHEAST ASIAN MONSOON REGION. GRAY SHADINGS DENOTE THE RANGE OF INTERNAL VARIABILITY, AND BLACK... view more 

CREDIT: LIXIA ZHANG

Southeast Asian monsoon region falls in the warm and humid tropics modulated by Asian monsoon. It is home to nearly 15% of the world's tropical forests and one of the biodiversity hotspots in the world.

With the unprecedented urbanization and population growing rate, water scarcity issues have already posed a serious challenge for sustainable development in Southeast Asian monsoon region. However, the impact of anthropogenic forcing, such as greenhouse gases and anthropogenic aerosols, on extreme drought events in the region is still unclear.

Scientists from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences investigated the observed drought changes over Southeast Asian monsoon region and impacts of anthropogenic forcing using the Coupled Model Intercomparison Project phase 6 (CMIP6) models.

Their findings were published in Geophysical Research Letters on June 1.

They revealed an increasing drought risk for 1951-2018 due to more frequent and wide-spread droughts over the Southeast Asian monsoon region.

They also detected the influence of anthropogenic forcing, which has increased the likelihood of the extreme droughts in historical simulation by reducing precipitation and enhancing evapotranspiration.

The time of emergence (ToE) of anthropogenic forcing in extreme drought frequency and affected area firstly appeared around the 1960s. Even though drought risk will start to decrease since the 2030s in the future under the lowest emission scenario of CMIP6, the projected drought risks are still beyond the changes caused by nature alone.

"The impact of anthropogenic forcing on drought risk over Southeast Asia has already exceeded internal climate variability in the late 20th century. It is urgent to take actions to reduce anthropogenic aerosol loading and greenhouse gas emissions to reduce drought risks in Southeast Asia." Said Dr. Lixia Zhang, the lead author of the study.

 

Bronze Age Scandinavia's trading networks for copper settled

Crossing the North Sea before crossing the Alps!

AARHUS UNIVERSITY

Research News

New research presents over 300 new analyses of bronze objects, raising the total number to 550 in 'the archaeological fingerprint project'. This is roughly two thirds of the entire metal inventory of the early Bronze Age in southern Scandinavia. For the first time, it was possible to map the trade networks for metals and to identify changes in the supply routes, coinciding with other socio-economic changes detectable in the rich metal-dependent societies of Bronze Age southern Scandinavia.

The magnificent Bronze Age in southern Scandinavia rose from copper traded from the British Isles and Slovakia 4000 years ago. 500 years later these established trade networks collapsed and fresh copper was then traded from the southern Alps, the so-called Italian Alps. This large-scale study could show that during the first 700 years of the Nordic Bronze Age the metal supplying networks and trade routes changed several times. These 700 years of establishment and change led to a highly specialised metalwork culture boasting beautiful artwork such as the Trundholm Sun wagon and spiral decorated belt plates branding high-ranking women; even depicted on today's Danish banknotes.

The study by H. Nørgaard, Moesgaard Museum and her colleagues H. Vandkilde from Aarhus University and E. Pernicka from the Curt-Engelhorn Centre in Mannheim built on the so far largest dataset of chemical and isotope data of ancient bronze artefacts. In total 550 objects were used to model the changes that took place: These changes correlate with major shifts in social organisation, settlements, housing, burial rites and long distance mobility.

"Now, this multi-disciplinary approach - based jointly on conventional archaeological methods and novel scientific methodologies processing large data quantities - allows us to detect these correlating changes and identify contemporaneity with societal changes recognised by colleague researchers", says Heide Nørgaard the project´s PI.

"It is highly likely that both people and technologies arrived to Scandinavia and that Scandinavians travelled abroad to acquire copper by means of the Nordic amber, highly valued by European trading partners".


CAPTION

Shafthole axe of Valsømagle type. Only a few axes of this type are known, and they are only distributed in northern Europe. These axes seem to be contemporary with the Fårdrup type axes as they are made of the same metal and not, if they would be slightly later, of the new Italian metal that is the main metal used in the period from 1500 BC.

CREDIT

Photo: Heide W. Nørgaard, by permission of the National Museum, Copenhagen.


CAPTION

The lead isotope plot of the over 65 shafthole axes analyzed in this study dating to the end of the first Bronze Age period 1600 BC. This amount of data exceeds the previous analyses by ten times and for the first time allows to compare both axe types and understand their development.

Citation: Nørgaard HW, Pernicka E, Vandkilde H (2021) Shifting networks and mixing metals: changing metal trade routes to Scandinavia correlate with Neolithic and Bronze Age transformations. PLOS ONEhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.0252376

In your coverage please use this URL to provide access to the freely available article in PLOS ONEhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.0252376