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Since 2020, the world has faced two unprecedented shocks: lockdowns (regulation) and the invasion of Ukraine (war). Although we realise the health and economic effects of these shocks, more research is needed on the effect on happiness and whether the type of shock plays a role. Therefore, in this paper, we determine whether these macro-level shocks affected happiness, how these effects differ, and how long it takes for happiness to adapt to previous levels. The latter will allow us to test whether adaptation theory holds at the macro level. We use a unique dataset of ten countries spanning the Northern and Southern hemispheres derived from tweets extracted in real-time per country. Applying Natural Language Processing, we obtain these tweets' underlying sentiment scores, after which we calculate a happiness score (Gross National Happiness) and derive daily time series data. Our Twitter dataset is combined with Oxford's COVID-19 Government Response Tracker data. Considering the results of the Difference-in-Differences and event studies jointly, we are confident that the shocks led to lower happiness levels, both with the lockdown and the invasion shock. We find that the effect size is significant and that the lockdown shock had a bigger effect than the invasion. Considering both types of shocks, the adaptation to previous happiness levels occurred within two to three weeks. Following our findings of similar behaviour in happiness to both types of shocks, the question of whether other types of shocks will have similar effects is posited. Regardless of the length of the adaptation period, understanding the effects of macro-level shocks on happiness is essential for policymakers, as happiness has a spillover effect on other variables such as production, safety and trust. [ABSTRACT FROM AUTHOR]

The linkages between the US and China, the world's two major agricultural powers, have brought great uncertainty to the global food markets. Inspired by these, this paper examines the extreme risk spillovers between US and Chinese agricultural futures markets during significant crises. We use a copula-conditional value at risk (CoVaR) model with Markov-switching regimes to capture the tail dependence in their pair markets. The study covers the period from January 2006 to December 2022 and identifies two distinct dependence regimes (stable and crisis periods). Moreover, we find significant and asymmetric upside/downside extreme risk spillovers between the US and Chinese markets, which are highly volatile in crises. Additionally, the impact of international capital flows (the financial channel) on risk spillovers is particularly pronounced during the global financial crisis. During the period of the COVID-19 pandemic and the Russia-Ukraine 2022 war, the impact of supply chain disruptions (the non-financial channel) is highlighted. Our findings provide a theoretical reference for monitoring the co-movements in agricultural futures markets and practical insights for managing investment portfolios and enhancing food market stability during crises. [ABSTRACT FROM AUTHOR]

This paper offers an empirical investigation of the narrative profiles afforded by public, one-way messaging channels on Telegram. We define these narrative profiles in terms of the contribution of messages to a thread of narrative continuity, and test the double hypothesis that 1) Telegram channels afford diverse narrative profiles, corresponding with distinct vernacular uses of the platform's features, and that 2) networks of Telegram channels sampled from thematically distinct seed channels lean towards distinct profiles. To this end, we analyse the textual contents of 2,724,187 messages from 492 public messaging channels spanning five thematic networks. Our computational method builds up the narrative profiles by scrolling down channels and classifying each message according to its narrative fit with the surrounding messages. We thus find that Telegram channels afford several distinct storytelling profiles, which tend to defy traditional notions of narrative coherence. We furthermore observe correspondences between the thematic orientations of channels and their narrative profiles, with a preference for disparate profiles in channels pertaining to conspiracy theories and far-right counterculture, a preference for coherent profiles in channels pertaining to cryptocurrencies, and mixed types in channels pertaining to disinformation about the war in Ukraine. These empirical observations thus inform our further theorization on how platform features allow users to construct and shape narratives online. [ABSTRACT FROM AUTHOR]

The objective of the paper is to diagnose organisational culture of selected universities and analyse its impact on the innovation processes within them. The subject matter of the study was organisational culture and innovation at universities. The subjects were four selected universities in Poland, Austria, Germany, and Ukraine. The paper provided a definition of organisational culture and its typology. It further discussed the organisational culture of universities and the relationships between organisational culture and innovativeness. The literature review provided foundations for building a model for the formation of a type of organisational culture at universities that is innovation-friendly, which is the added value of the paper. It offers actions worth taking to shape innovation-friendly culture at universities. It is particularly important during difficult time of changing labour market, when universities greatly impact the attitudes of young people. The knowledge of how to shape innovation-friendly organisational culture at universities is necessary for academia to profile future employees in times of continuous changes. To investigate the relationship between organisational culture and the innovativeness of universities, we designed an original survey questionnaire [S1 File]. Organisational culture was diagnosed with the Organizational Culture Assessment Instrument by K.S. Cameron and R.E. Quinn. The analyses were conducted in Dell Statistica v. 13.1 (StatSoft Polska). We normalised data from the Likert rating scale using Kaufman's and Rousseeuw's formula. We used Spearman's correlation coefficient and Kendall's W to calculate correlations. The research shows that the investigated Polish and Austrian universities are dominated by hierarchy and market cultures. On the other hand, the German and Ukrainian universities host all cultures, but clan and adhocracy dominate there. Moreover, the analyses demonstrated that although the adhocracy culture was the least visible in the investigated organisations, it contributes to university innovativeness the most. The conclusions were used to build a model for promoting innovation-friendly organisational culture at universities. The model contains answers to the research questions. In addition, it offers guidelines for shaping organisational culture to bolster innovation at universities. The research identified relationships between organisational culture and university innovativeness and components that create innovation opportunities at universities as its contribution to management theory. When applied in practice, the guidelines can help form the university's organisational culture bottom-up. [ABSTRACT FROM AUTHOR]

Accession of Poland to the European Single Market generated trade creation and diversion effects, which in turn resulted in a high degree of concentration of the Polish foreign trade in agri-food products with other EU countries. On the one hand, a high share of export to the markets of countries with a stable market economy is a confirmation of the Polish agri-food sector's capacity to compete on the foreign markets. On the other hand, when considering limited capability to increase food demand in the EU it provides grounds for the assumption that further export expansion to a considerable extent will depend on the potential expansion of sale to non-EU markets. In this context significant issues include diversification of target markets and search for prospective markets outside the EU, while they also determine directions of an advantageous export specialization. In the period up to 2021 the USA was the fourth non-EU export partner of Poland in the agri-food sector after the United Kingdom, Ukraine and Russia. The aim of this paper is to evaluate the level of comparative advantages of the Polish agri-food sector on the EU and US markets in 2004–2021 using Widodo's products mapping technique. The study used statistical data from the ComExt database of the European Statistical Office (Eurostat). The conducted studies showed Polish export specializations in the transatlantic trade, as confirmed by high comparative advantages, as well as a positive and steadily improving trade balances for food preparations, including meat, cereal, fruit and vegetable, as well as confectionery preparations, and less processed animal origin products (meat and offal as well as dairy produce). Poland had a disadvantageous competitive position in trade of products complementary in relation to domestic production, which import was necessary. In view of the comparative cost theory the directions of the realized export specialization were rational and should be maintained. While in trade with the other EU countries the competitive position of the Polish agri-food sector was weakened, it was strengthened on the US market. In view of the considerable EU market saturation the improved competitive capacity in the non-EU markets is a positive development, which is a promising finding particularly in the long-term perspective. [ABSTRACT FROM AUTHOR]

Achievement of viral load suppression among people living with HIV is one of the most important goals for effective HIV epidemic response. In Ukraine, people who inject drugs (PWID) experience the largest HIV burden. At the same time, this group disproportionally missed out in HIV treatment services. We performed a secondary data analysis of the national-wide cross-sectional bio-behavioral surveillance survey among PWID to assess the population-level prevalence of detectable HIV viremia and identify key characteristics that explain the outcome. Overall, 11.4% of PWID or 52.6% of HIV-positive PWID had a viral load level that exceeded the 1,000 copies/mL threshold. In the group of HIV-positive PWID, the detectable viremia was attributed to younger age, monthly income greater than minimum wage, lower education level, and non-usage of antiretroviral therapy (ART) and opioid agonistic therapy. Compared with HIV-negative PWID, the HIV-positive group with detectable viremia was more likely to be female, represented the middle age group (35–49 years old), had low education and monthly income levels, used opioid drugs, practiced risky injection behavior, and had previous incarceration history. Implementing the HIV case identification and ART linkage interventions focused on the most vulnerable PWID sub-groups might help closing the gaps in ART service coverage and increasing the proportion of HIV-positive PWID with viral load suppression. [ABSTRACT FROM AUTHOR]

The global food prices have surged to historical highs, and there is no consensus on the reasons behind this round of price increases in academia. Based on theoretical analysis, this study uses monthly data from January 2000 to May 2022 and machine learning models to examine the root causes of that period's global food price surge and global food security situation. The results show that: Firstly, the increase in the supply of US dollars and the rise in oil prices during pandemic are the two most important variables affecting food prices. The unlimited quantitative easing monetary policy of the US dollar is the primary factor driving the global food price surge, and the alternating impact of oil prices and excessive US dollar liquidity are key features of the surge. Secondly, in the context of the global food shortage, the impact of food production reduction and demand growth expectations on food prices will further increase. Thirdly, attention should be paid to potential agricultural import supply chain risks arising from international uncertainty factors such as the ongoing Russia-Ukraine conflict. The Russian-Ukrainian conflict has profoundly impacted the global agricultural supply chain, and crude oil and fertilizers have gradually become the main driving force behind the rise in food prices. [ABSTRACT FROM AUTHOR]

This paper examines the issue of employee discrimination after a political crisis: the annexation of Crimea. The annexation, which resulted in a political crisis in Russian-Ukrainian relations, is a setting which allows us to test if a bilateral political issue caused employee discrimination. We use a quasi-experimental approach to examine how the political crisis influenced participation in major sports leagues in Russia and Ukraine. The results show that the employment conditions significantly worsened since the Crimea crisis started. [ABSTRACT FROM AUTHOR]

Recently, high-resolution magnetometry surveys have led to the discovery of a special category of buildings–so-called ‘mega-structures’–situated in highly visible positions in the public space of Tripolye giant-settlements of the late 5th and first half of the 4th millennium BCE. In this paper we explore what these buildings actually are and how they can contribute to the understanding of the development of social space in Tripolye giant-settlements. For this investigation, we linked newly obtained excavation data from the giant-settlement Maidanetske, Ukraine, with a much larger sample of such buildings from magnetic plans obtained in the region between the Carpathian foothills and the Dnieper River. Accordingly, Tripolye mega-structures represent a particular kind of integrative building documented in many non-ranked ethnographic contexts. Based on our results we are interpreting that these buildings were used for various ritual and non-ritual activities, joint decision-making, and the storage and consumption of surplus. In Tripolye giant-settlements at least three different categories of mega-structures could be identified which most likely represent different levels of socio-political integration and decision-making. The emergence of this hierarchical system of high-level integrative buildings for the whole community and different low-level integrative architectures for certain segments of local communities was related to the rise of Tripolye mega-sites. The presence of different integrative levels most likely reflects the fusion of different previously independent communities in the giant-settlements. Later in the mega-site development, we observe how low-level integrative buildings increasingly lose their importance indicated by shrinking size and, finally, their disappearance. This observation might indicate that the power which was previously distributed across the community was transferred to a central institution. It is argued that the non-acceptance of this concentration of power and the decline of lower decision-making levels might be a crucial factor for the disintegration of Tripolye giant-settlements around 3600 BCE. [ABSTRACT FROM AUTHOR]

Background: Ukraine has the second-largest HIV epidemic in Europe, with most new cases officially attributed to heterosexual transmission. Indirect evidence suggested substantial HIV transmission from people who inject drugs (PWID) to their sexual partners. This study examined the extent of heterosexual HIV transmission between PWID and non-drug-using adolescent girls and young women (AGYW). Methods: A cross-sectional survey recruited AGYW diagnosed with heterosexually-acquired HIV between 2016 and 2019 in nine regions of Ukraine. AGYW were asked to identify and refer their sexual partners ('Partners'), who subsequently underwent HIV testing, and, if positive, HCV testing. Both AGYW and Partners completed an interview assessing HIV risk behaviors prior to AGYW's HIV diagnosis. Results: In August-December 2020, we enrolled 321 AGYW and 64 Partners. Among the Partners, 42% either self-reported IDU or were HCV-positive, indicating an IDU-related mode of HIV transmission. PWID Partners were more likely to report sexually transmitted infections (STI) and had lower educational levels. Of the 62 women who recruited at least one Partner, 40% had a PWID Partner. Within this subgroup, there was a higher prevalence of STIs (52% vs. 24%) and intimate partner violence (36% vs. 3%). Condom use was less common (52% vs. 38% reporting never use), and frequent alcohol or substance use before sex was higher (48% vs 30%) among AGYW with PWID Partner, although this difference did not reach statistical significance. Notably, 52% of women were aware of their Partners' IDU. Conclusion: At least 40% of heterosexual transmission among AGYW in Ukraine can be linked to PWID partners. Intensified, targeted HIV prevention efforts are essential for key and bridge populations (PWID and their sexual partners), addressing the biological and structural determinants of transmission between key and bridge populations, such as IDU- and HIV status disclosure, STIs, IPV, and stigma. [ABSTRACT FROM AUTHOR]

Wars increase the importance of government functions, yet they also constrain their ability to fulfill these functions. In particular, wars hinder economic activity, thereby limiting governments' capacity to raise the revenues required to maintain stability and meet the heightened needs of citizens. Effective governance is therefore severely undermined in times of war. However, empirical research on how wars affect government procurement is limited. We address this gap by exploring procurement dynamics using over one million public purchases of goods and services in Ukraine between January 2021 and October 2022, corresponding to the Russian invasion of the country. We document a large fall in the total number of purchases since the invasion and an increase in the share of successfully completed procurements. This higher success rate comes at the cost of efficiency, with the government paying more to source their goods. This can be attributed to the decline in the share of government purchases via online auctions and the reduced competition. Thus, the prioritization of the quick acquisition of goods and services forced governments to sacrifice cost-effectiveness. In summary, the war did not lower the successful purchasing of private goods and services, and transparency was not decreased. However, the trade-off of speed and transparency for greater costs may become increasingly problematic with the growing budget constraints resulting from the war. This article contributes to our understanding of the Ukrainian government choices during the early phase of the war. The results also highlight the importance of ensuring procurement efficiency and transparency when the war ends as reconstruction efforts will require substantial increases in government procurements. [ABSTRACT FROM AUTHOR]

Background: The Ukrainian Ministerial Order (UMO) recommends pneumococcal vaccine (PCV) in risk groups but not free-of-charge resulting in coverage <5% (crude estimation). In 2022, the vaccination calendar will include PCV for children <5years. Doctors' pneumococcal knowledge, attitudes and practices (КAP) are paramount to successful roll-out but unexplored. We surveyed doctors aiming to assess their KAP to address gaps and misconceptions and support PCV implementation. Methods: In March 2021, we selected and surveyed primary care doctors using simple random sampling and structured self-administered online questionnaire. We measured attitudes (importance, effectiveness, safety) and practices using 5-point Likert-type questions. We defined pneumococcal disease (PD) knowledge as low/moderate (<80%) and high (≥80%), PCV and overall knowledge as low (≤50%) and moderate/high (51–100%) and PCV attitudes and practices as negative/neutral (1.0–3.4) and positive (3.5–5.0). We calculated prevalence ratios (PRs) and 95% confidence intervals (95%CI) using Poisson regression. Results: The response rate was 46% (286/628). Females represented 85% (243/285); the median age was 47 (interquartile range: 33–59, N = 281) years. Twenty-six percent (72/277) had high PD knowledge associated with age (>47 years: PR = 0.52, 95%CI: 0.30–0.90) and child-related UMO awareness (PR = 1.78, 95%CI: 1.04–3.08); 65% (182/278) had moderate/high PCV knowledge associated with positive attitudes towards PCV effectiveness (PR = 2.08, 95%CI: 1.20–3.59). Overall knowledge was moderate/high in 69% (188/271); 83% (220/265) had positive PCV attitudes; 52% (135/258) had positive practices associated with female sex (PR = 2.11, 95%CI: 1.09–4.09), positive attitudes (PR = 3.40, 95%CI: 1.23–9.39) and perception of vaccine supply as medium/big barrier (PR = 1.66, 95%CI: 1.02–2.72). Conclusion: We observed moderate pneumococcal knowledge, especially in older doctors, positive PCV attitudes and neutral practices. Females and doctors with positive attitudes recommended PCV more. For successful PCV implementation, we recommend proper planning and prior educational activities targeting patients and primary care doctors, especially older males, to improve knowledge, introduce PCV and address concerns while ensuring uninterrupted vaccine supply. [ABSTRACT FROM AUTHOR]

Ukraine's tug-of-war between Russia and the West has had significant and lasting consequences for the country. In 2013, Viktor Yanukovych, the Ukrainian president aligned with Russia, opted against signing an association agreement with the European Union. This agreement aimed to facilitate trade and travel between the EU and Ukraine. This decision sparked widespread protests that coalesced in Kyiv's Maidan Square, eventually becoming known as the Euromaidan protests. In this study, we analyze the protest data from 2013, sourced from Ukraine's Center for Social and Labor Research. Despite the dataset's limitations and occasional inconsistencies, we demonstrate the extraction of valuable insights and the construction of a descriptive model from such data. Our investigation reveals a pre-existing state of self-excitation within the system even before the onset of the Euromaidan protests. This self-excitation intensified during the Euromaidan protests. A statistical analysis indicates that the government's utilization of force correlates with increased future protests, exacerbating rather than quelling the protest movement. Furthermore, we introduce the implementation of Hawkes process models to comprehend the spatiotemporal dynamics of the protest activity. Our findings highlight that, while protest activities spread across the entire country, the driving force behind the dynamics of these protests was the level of activity in Kyiv. Furthermore, in contrast to prior research that emphasized geographical proximity as a key predictor of event propagation, our study illustrates that the political alignment among oblasts, which are the distinct municipalities comprising Ukraine, had a more profound impact than mere geographic distance. This underscores the significance of social and cultural factors in molding the trajectory of political movements. [ABSTRACT FROM AUTHOR]

Background: Belarus and Ukraine were the countries most affected by the consequences of the Chornobyl nuclear power plant in 1986. A study of perinatal mortality in Belarus found a highly statistically significant increase in the 1990s in the most contaminated oblast Gomel but no increase during this period in the rest of Belarus. As a possible mechanism to interpret this increase as a late Chornobyl effect, it has been suggested that strontium-90 contained in Chornobyl fallout, incorporated during menarche, impairs the immune system of pregnant women which in turn increases perinatal mortality. In the present study, this hypothesis is tested using data from Ukraine. Methods: Annual data on perinatal mortality, in the period 1981–2006 were provided by the Ministry of Public Health of Ukraine. Trends in perinatal mortality rates in the most contaminated regions of Ukraine (Kyiv and Zhytomyr oblasts and the city of Kyiv; study region) were compared with rates in the rest of Ukraine (control region). To identify any differences in perinatal mortality trends between the study and control regions, the ratios of perinatal mortality rates in the study region to the rates in the control region were analyzed using the calculated strontium concentration as a predictor. Results: A trend analysis of perinatal mortality rates in Ukraine revealed two bell-shaped deviations from a long-term exponential trend with maxima at the beginning and end of the 1990s. The same pattern was found in the data from the study and control regions, but the deviations were almost three times higher in the study region than in the control region. An analysis of the ratios of perinatal mortality rates in the study region to the rates in the control region (odds ratios) showed an increase and decrease during the 1990s which was approximated by a lognormal density distribution. The calculated strontium concentration, when used as a predictor, also fitted the data well. Thus, the data from Ukraine confirms the results from Belarus. The analysis of the odds ratios revealed about 1000 excess perinatal deaths in the study region in the period 1990–2004. The corresponding figure for Ukraine as a whole was estimated at 3500 perinatal deaths. Conclusion: It is hypothesized that the observed increase in perinatal mortality in the 1990s may be a late effect of incorporated strontium-90 on the immune system of pregnant women. The analysis is based on a theoretical model, as no data on strontium concentrations were available; the results should therefore be interpreted with caution. An updated study for Belarus would be desirable to corroborate the results. [ABSTRACT FROM AUTHOR]

Based on monthly economic data spanning from January 2015 to December 2022, we have established an analytical framework to examine the "Russia-Ukraine conflict—financial market pressure and energy market—China carbon emission trading prices." To achieve this objective, we developed indices for financial system pressure, the energy market, and investor sentiment, applying a mediation effects model to validate their transmission mechanisms. Subsequently, the TVP-SV-VAR model was employed to scrutinize the nonlinear impact of the Russia-Ukraine conflict on the valuation of China's carbon emission trading rights. This model integrates time-varying parameters (TVP) and stochastic volatility (SV), utilizing Markov Chain Monte Carlo (MCMC) technology for parameter estimation. Finally, various wavelet analysis techniques, including continuous wavelet transform, cross-wavelet transform, and wavelet coherence spectrum, were applied to decompose time series data into distinct time-frequency scales, facilitating an analysis of the lead-lag relationships within each time series. The research outcomes provide crucial insights for safeguarding the interests of trading organizations, refining the structure of the carbon market, and mitigating systemic risks on a global scale. [ABSTRACT FROM AUTHOR]

We investigate the dynamic volatility connectedness of geopolitical risk, stocks, bonds, bitcoin, gold, and oil from January 2018 to April 2022 in this study. We look at connectivity during the Pre-COVID, COVID, and Russian-Ukraine war subsamples. During the COVID-19 and Russian-Ukraine war periods, we find that conventional, Islamic, and sustainable stock indices are net volatility transmitters, whereas gold, US bonds, GPR, oil, and bitcoin are net volatility receivers. During the Russian-Ukraine war, the commodity index (DJCI) shifted from being a net recipient of volatility to a net transmitter of volatility. Furthermore, we discover that bilateral intercorrelations are strong within stock indices (DJWI, DJIM, and DJSI) but weak across all other financial assets. Our study has important implications for policymakers, regulators, investors, and financial market participants who want to improve their existing strategies for avoiding financial losses. [ABSTRACT FROM AUTHOR]

This study investigates the dynamic and asymmetric propagation of return spillovers between sectoral commodities and industry stock markets in China. Using a daily dataset from February 2007 to July 2022, we employ a time-varying vector autoregressive (TVP-VAR) model to examine the asymmetric return spillovers and dynamic connectedness across sectors. The results reveal significant time-varying spillovers among these sectors, with the industry stocks acting as the primary transmitter of information to the commodity market. Materials, energy, and industrials stock sectors contribute significantly to these spillovers due to their close ties to commodity production and processing. The study also identifies significant asymmetric spillovers with bad returns dominating, influenced by major economic and political events such as the 2008 global financial crisis, the 2015 Chinese stock market crisis, the COVID-19 pandemic, and the Russia-Ukraine war. Furthermore, our study highlights the unique dynamics within the Chinese market, where net information spillovers from the stock market to commodities drive the financialization process, which differs from the bidirectional commodity financialization observed in other markets. Finally, portfolio analysis reveals that the minimum connectedness portfolio outperforms other approaches and effectively reflects asymmetries. Understanding these dynamics and sectoral heterogeneities has important implications for risk management, policy development, and trading practices. [ABSTRACT FROM AUTHOR]

Almost eight million Ukrainians have fled their country to escape the Russian full-scale invasion. To provide empirical evidence on how beneficiaries of temporary protection who reside in the immediate proximity of Ukraine differ from those who went further and reside in Western European countries, two large-scale rapid-response surveys were conducted in Kraków, Poland, and Vienna, Austria, in spring 2022. Data include information on socio-demographic characteristics, human capital, and return intentions of 472 and 1,094 adult Ukrainian refugees in Poland and Austria, respectively. Contributing to the growing empirical evidence on consistent assortative patterns in refugee inflows into Europe, our findings show that regularities in patterns of self-selection also occur in forced migration contexts where legal routes to safety apply. According to the analysed convenience sample, a tentative conclusion is that the further Ukrainian refugees moved to the West, the more self-selected they tend to be in the key dimensions of formal educational attainment, previous employment, language skills, and urbanity. Results indicate that willingness to stay in Kraków is significantly lower than willingness to remain in Vienna. This suggests that public financial support and living conditions, rather than diaspora networks, are decisive factors in shaping the decision to stay, move to another location or return to Ukraine. The aim to start a new life elsewhere may drive the motivation to choose a more distant destination instead of a neighboring country that allows to return rather quickly. Host countries should be aware of these specific characteristics of their refugee populations and adapt their integration policies accordingly. [ABSTRACT FROM AUTHOR]

Leather was one of the most important materials of nomadic Scythians, used for clothing, shoes, and quivers, amongst other objects. However, our knowledge regarding the specific animal species used in Scythian leather production remains limited. In this first systematic study, we used palaeoproteomics methods to analyse the species in 45 samples of leather and two fur objects recovered from 18 burials excavated at 14 different Scythian sites in southern Ukraine. Our results demonstrate that Scythians primarily used domesticated species such as sheep, goat, cattle, and horse for the production of leather, while the furs were made of wild animals such as fox, squirrel and feline species. The surprise discovery is the presence of two human skin samples, which for the first time provide direct evidence of the ancient Greek historian Herodotus' claim that Scythians used the skin of their dead enemies to manufacture leather trophy items, such as quiver covers. We argue that leather manufacture is not incompatible with a nomadic lifestyle and that Scythians possessed sophisticated leather production technologies that ensured stable supply of this essential material. [ABSTRACT FROM AUTHOR]

Deepfakes are a form of multi-modal media generated using deep-learning technology. Many academics have expressed fears that deepfakes present a severe threat to the veracity of news and political communication, and an epistemic crisis for video evidence. These commentaries have often been hypothetical, with few real-world cases of deepfake's political and epistemological harm. The Russo-Ukrainian war presents the first real-life example of deepfakes being used in warfare, with a number of incidents involving deepfakes of Russian and Ukrainian government officials being used for misinformation and entertainment. This study uses a thematic analysis on tweets relating to deepfakes and the Russo-Ukrainian war to explore how people react to deepfake content online, and to uncover evidence of previously theorised harms of deepfakes on trust. We extracted 4869 relevant tweets using the Twitter API over the first seven months of 2022. We found that much of the misinformation in our dataset came from labelling real media as deepfakes. Novel findings about deepfake scepticism emerged, including a connection between deepfakes and conspiratorial beliefs that world leaders were dead and/or replaced by deepfakes. This research has numerous implications for future research, societal media platforms, news media and governments. The lack of deepfake literacy in our dataset led to significant misunderstandings of what constitutes a deepfake, showing the need to encourage literacy in these new forms of media. However, our evidence demonstrates that efforts to raise awareness around deepfakes may undermine trust in legitimate videos. Consequentially, news media and governmental agencies need to weigh the benefits of educational deepfakes and pre-bunking against the risks of undermining truth. Similarly, news companies and media should be careful in how they label suspected deepfakes in case they cause suspicion for real media. [ABSTRACT FROM AUTHOR]

In this work the new species of Stomiosphaerina bakae sp. nov. is described. This is the third species of the genus Stomiosphaerina. Several dozen specimens of the newly described species were found within the Upper Cretaceous (upper Turonian) white chalk at Dubivtsi section near Halych in western Ukraine (south-eastern margin of Central European Basin). Stomiosphaerina bakae sp. nov. has an asymmetrical oval (pear-like shape) test, as it is wider in one side, and sharp in the opposite side, ranging from 55 to 67 μm in length and from 42 to 56.5 μm in width. It has a two-layered calcareous test. The outer layer, with thickness ranging from 4.5 to 6.5 μm, is built of long and wide plate-shaped calcite crystals and is white in plain-polarized light with a dark cross in crossed-polarized light. The inner layer, with thickness ranging from 1.5 to 4.5 μm, is yellowish, goldish to brownish color in plain-polarized light, with proximal and distal side smooth and even, and is built of short fibrous calcite crystals, without preferential orientation. One narrow (6 to 8 μm width) aperture is observed. Stomiosphaerina bakae sp. nov. differs from other species of Stomiosphaerina, i.e. Stomiosphaerina biedai Nowak 1974 and Stomiosphaerina proxima Řehánek 1987, by its cyst-shape, cyst-size, layers thickness, structure of outer layer and width of aperture. Stomiosphaerina bakae sp. nov. most likely corresponds to the non-defined species of Stomiosphaerina sp. described by Nowak 1974. [ABSTRACT FROM AUTHOR]

Are green investments decoupled from the dirty investment such as the fossil fuel markets? We address this issue by extending the literature on environmental, social, and governance (ESG) assets by examining the dynamic relationship between fossil fuels and digital ESG assets proxied by green cryptocurrencies using the TVP-VAR(Time-varying parameter vector auto regression) spillover framework. Furthermore, we analyze the hedging attributes of green cryptocurrencies and fossil fuels in a minimum connectedness framework. The main findings are as follows: First, green cryptocurrencies are the main shock transmitters in all asset systems. Second, the dynamic connectedness between green cryptocurrencies and fossil fuels increased during the COVID-19 and Russia-Ukraine conflicts. Third, green cryptocurrencies have shown considerable hedging effectiveness against the fossil fuels. Our study has important implications for investors, regulators, and policy makers, such as shifting to green cryptocurrencies, regulation of carbon footprint, and promoting eco-friendly assets. [ABSTRACT FROM AUTHOR]

Financial distress is generally considered the most severe consequence for firms with poor financial performance. The emergence of the Covid-19 pandemic has adversely impacted the global business system and exacerbated the number of financially distressed firms in many countries. Only firms with strong financial fundamentals can survive extreme events such as the Covid-19 pandemic and the ongoing Russia-Ukraine conflict. Vietnam is no exception. However, studies examining financial distress using accounting-based indicators, particularly at the industry level, have largely been ignored in the Vietnamese context, particularly with the emergence of the Covid-19 pandemic. This study, therefore, comprehensively examines financial distress for 500 Vietnamese listed firms during the 2012–2021 period. Our study uses interest coverage and times-interest-earned ratios to proxy a firm's financial distress. First, our findings confirm the validity of Altman's Z"- score model in Vietnam only when the interest coverage ratio is used as a proxy for financial distress. Second, our empirical findings indicate that only four financial ratios, including EBIT/Total Assets, Net Income/Total Assets, Total Liabilities/Total Assets, and Total Equity/Total Liabilities, can be used in predicting financial distress in Vietnam. Third, our analysis at the industry level indicates that the "Construction & Real Estates" industry, a significant contributor to the national economy, exhibits the most significant risk exposure, particularly during the Covid-19 pandemic. Policy implications have emerged based on the findings from this study. [ABSTRACT FROM AUTHOR]

The mortality impact of the COVID-19 pandemic in Ukraine has remained incomplete. We estimated excess deaths associated with the pandemic in Ukraine during 2020 and 2021. Excess deaths may be attributed directly to SARS-CoV-2 infection or indirectly to deaths associated with social and economic upheavals resulting from the pandemic. Data on all deaths registered in government-controlled Ukraine from 2016–2021 (N = 3,657,475) were utilized. Using a model-based approach, we predicted monthly excess deaths in 2020 and 2021. We estimated 47,578 excess deaths in 2020 as a whole (7.71% of all recorded deaths). This figure reflects both positive (higher than expected) excess deaths from June-December and negative (lower than expected) deaths in January and March-May. From June-December 2020, we estimated 59,363 excess deaths (15.75% of all recorded deaths in those months). In 2021, we estimated 150,049 excess deaths (21.01% of all recorded deaths). Positive excess deaths were detected across age groups even groups younger than 40 years. The number of excess deaths exceeded that of deaths with COVID-19 coded on the death certificate by more than two-fold in 2020, but that difference narrowed in 2021. We furthermore provide provisional estimates of the effect of low vaccine coverage on excess deaths in 2021 drawing from European cross-national evidence and provisional estimates of the hypothetical evolution of the pandemic in 2022 to serve as a rough basis for future studies analyzing the joint impacts of the COVID-19 pandemic and the Russian invasion on Ukrainian demography. [ABSTRACT FROM AUTHOR]

How can states with a history of recent armed conflict trust one another? Political psychology offers two competing approaches to increase trust between the publics of different countries: appealing to an overarching, common identity above the national level vs. affirming a sense of national identity. This study aims to examine the scope conditions of group-affirmation effects on trust in active conflicts by testing which group-affirmation approach increases trust towards Russia among the Ukrainian public. Distrust between Ukraine and Russia aggravates security fears and limits hope for a meaningful resolution of the bloodiest armed conflict in Europe since 1994. Hostility levels have risen dramatically between the populations of Ukraine and Russia after the events of 2013–2015. The study employs a survey experiment (between-subjects design) to evaluate these competing approaches. The survey was fielded in late May-June 2020 by a reputable public opinion research firm, the Kyiv International Institute of Sociology (KIIS), based in Ukraine. The results suggest that in areas where conflict is salient, national identity affirmation can increase trust in subsamples that hold preexisting baseline levels of affinity toward the outgroup. When combined with the more anti-Russian Ukrainians however, this positive effect was cancelled out. In contrast, emphasis on an overarching, common ingroup identity did not raise trust in any subgroups. Examining the disparate effects of national identity affirmation in anti-Russian and pro-Russian regional subsamples helps specify the scope conditions of which group-affirmation can be most effective. [ABSTRACT FROM AUTHOR]

The proliferation of country and state-level net zero-emission commitments, rising energy costs, and the quest for energy security in the wake of the Ukraine crisis have renewed the debate about the future of energy sources. As opposed to elite discourse, the energy policy preferences of the public remain less explored. While many public opinion surveys report preferences for a specific type of clean energy, there is less work on understanding choices among different types. We explore whether support for nuclear over wind energy at the state level depends on how people assess the impact of these energy sources on health, local jobs, landscape disruption, and the stability of the electricity supply. Importantly, we seek to understand where people physically reside (and their experience of existing energy possibilities) might influence their energy policy preferences. We estimate multiple regression models with OLS with our original survey data of a representative sample of Washington residents (n = 844). We find that the physical proximity to existing energy facilities does not influence support for nuclear over wind energy. However, this support is shaped by the importance respondents attach to health (-), jobs (-), landscapes (+), and supply stability (+) dimensions of energy source. Moreover, the physical proximity to existing energy facilities moderates the importance respondents attach to these dimensions. [ABSTRACT FROM AUTHOR]

Economic security can be considered as an economic aspect of the life of an individual or household that provides the opportunity to achieve financial stability and improve living standards. In this context, understanding the impact of economic affordability of food on the economic security of the country is of great importance. The authors propose to use the indicator of economic affordability of food for in-depth analysis of the economic security of the country. Indicators that determine the level of economic affordability of food products in Ukraine for 2000–2018 are calculated. The regression analysis made it possible to establish a close relationship between the indicators of food expenditures and the level of GDP per capita, between the level of income and expenditure of food of decile groups. Correlation coefficients between the consumption of six basic foodstuffs and the level of per capita income in Ukraine are determined. The obtained indicators, which determine the economic affordability of food, allow us to conclude that there is a lack of economic protection at the level of individual low-income households. Overcoming economic instability and minimizing the possible consequences of the low level of economic affordability of food should become one of the main tasks of Ukraine's economic security. [ABSTRACT FROM AUTHOR]

Free-roaming dog population management is conducted to mitigate risks to public health, livestock losses, wildlife conservation, and dog health and welfare. This study aimed to determine attitudes towards free-roaming dogs and their management and describe dog ownership practices in three European countries. We distributed an online questionnaire comprising questions relating to dog ownership practices and attitudes towards free-roaming dogs using social media. We used logistic regression and ordinal probit models to determine associations between demographic and other factors with ownership practices and attitudes towards free-roaming dogs. This study found that most surveyed respondents wanted to see a reduction in free-roaming dog numbers, and felt that this should be achieved through sheltering, catch-neuter-release, and by controlling owned dog breeding. We identified significant associations between both attitudes and ownership practices with gender, religious beliefs, age, education level, reason for dog ownership, previous experience with free-roaming dogs, and country of residence. Respondents who identified as: (i) male, (ii) holding religious beliefs, (iii) owning dogs for practical reasons, (iv) being young, or (v) having no schooling or primary education had a lower probability of neutering and a higher probability of allowing dogs to roam. Respondents who identified as: (i) female, (ii) feeling threatened by free-roaming dogs, (iii) older, or (iv) having more education had a higher probability of answering that increases in free-roaming dog numbers should be prevented. These findings can help to inform future dog population management interventions in these countries. We emphasise the importance of considering local attitudes and dog ownership practices in the development of effective dog population management approaches. [ABSTRACT FROM AUTHOR]

The provision of comprehensive prevention services is vital for reducing the high burden of HIV amongst Ukrainian female sex workers (FSWs). To identify barriers and facilitators that influence access to HIV prevention amongst this population between 2009 and 2017, we developed a literature-informed conceptual framework and conducted a document analysis to identify the components of the Ukrainian prevention package (PP). Using the Integrated Bio Behavioural Surveillance Surveys, we then conducted descriptive analyses to explore PP coverage from 2009 to 2017 and the influence of factors, identified by our conceptual framework. After increasing over four years, a drop in PP coverage was observed from 2013 onwards. Being a client of a non-governmental organisation, street and highway solicitation, non-condom use, and knowledge of HIV may influence access to HIV prevention in the Ukrainian context. Future interventions should consider barriers and facilitators to HIV prevention and the multiple structural levels on which they operate. [ABSTRACT FROM AUTHOR]

The Scythians are frequently presented, in popular and academic thought alike, as highly mobile warrior nomads who posed a great economic risk to growing Mediterranean empires from the Iron Age into the Classical period. Archaeological studies provide evidence of first millennium BCE urbanism in the steppe while historical texts reference steppe agriculture, challenging traditional characterizations of Scythians as nomads. However, there have been few direct studies of the diet and mobility of populations living in the Pontic steppe and forest-steppe during the Scythian era. Here, we analyse strontium, oxygen, and carbon isotope data from human tooth enamel samples, as well as nitrogen and carbon isotope data of bone collagen, at several Iron Age sites across Ukraine commonly associated with 'Scythian' era communities. Our multi-isotopic approach demonstrates generally low levels of human mobility in the vicinity of urban locales, where populations engaged in agro-pastoralism focused primarily on millet agriculture. Some individuals show evidence for long-distance mobility, likely associated with significant inter-regional connections. We argue that this pattern supports economic diversity of urban locales and complex trading networks, rather than a homogeneous nomadic population. [ABSTRACT FROM AUTHOR]

The Chernobyl Nuclear Power Plant accident released vast amounts of various fission products, of which 131I and 137Cs are considered the most important because they are a major source of radiation exposure to the general public. 137Cs, unlike 131I, has a 30-year half-life that continues to expose people internally and externally for several decades after being deposited into the ground. 137Cs can be easily transmitted to the body through the intake of products and wild forest foodstuffs produced in contaminated areas. In the early phase, external exposure to 137Cs was predominant; however, it gradually diminished, mostly owing to horizontal and vertical distribution, and internal exposure started gaining dominance. Prior studies have shown that people in the affected areas have been constantly subjected to the inevitable low-grade internal exposure, which in turn has led to high anxiety and concern regarding the potential health effects. The present 10-year study assessed the latest status of the body burden among residents of the contaminated parts of the Zhytomyr region of Ukraine by measuring the internal concentration of 137Cs using the whole-body counter installed at the Medical Center of Korosten city. Almost 110 000 examinees from eight different districts were screened between 2009 and 2018. The study area was situated to the west of Chernobyl, which experienced a significant fallout of 137Cs and 131I from the Chernobyl Nuclear Power Plant. We analyzed the data for internal exposure to 137Cs by obtaining the actual magnitude, pace, and pattern of change for each year. During the study, the average 137Cs concentration in residents fell from 21.6 Bq/kg at the beginning of the study to 3.0 Bq/kg at the end of the study. The proportion of examinees with detectable levels had also fallen rapidly, from 45% to 11%. We found a weaker seasonal effect and a significantly higher Bq/kg concentration in adolescents than in other age groups. [ABSTRACT FROM AUTHOR]

Romania and Ukraine share the Black Sea coastline, the Danube Delta and associated habitats, which harbor the endemic, aquatic Pontocaspian biota. Currently, this biota is diminishing both in numbers of species and their abundance because of human activities, and its future persistence strongly depends on the adequacy of conservation measures. Romania and Ukraine have a common responsibility to address the conservation of Pontocaspian biodiversity. The two countries, however have different socio-political and legal conservation frameworks, which may result in differences in the social network structure of stakeholder institutions with different implications for Pontocaspian biodiversity conservation. Here, we study the social network structure of stakeholder organizations involved in conservation of Pontocaspian biodiversity in Romania and the implications of network structure for conservation outcomes. Then we compare the findings from Romania to an earlier similar study from Ukraine. We apply a mix of qualitative and quantitative social network analysis methods to combine the content and context of the interactions with relational measures. We show that Pontocaspian biodiversity plays a minor and mostly incidental role in the inter-organizational interactions in Romania. Furthermore, there is room for improvement in the network structure through e.g. more involvement of governmental and nongovernmental organizations and increased motivation of central stakeholders to initiate conservation actions. Social variables, such as lack of funding, hierarchical, non-inclusive system of conservation governance and continuous institutional reforms in the public sector are consequential for the network relations and structure. Social network of stakeholders in Ukraine is more connected and central stakeholders utilize their favorable positions. However, neither in Ukraine is the Pontocaspian biodiversity a driver of organizational interactions. Consequently, both networks translate into sub-optimal conservation actions and the roads to optimal conservation are different. We end with sketching out conservation implications and recommendations for improved national and cross-border conservation efforts. [ABSTRACT FROM AUTHOR]

Aragonite (along with calcite) is one of the most common polymorphs of the crystalline calcium carbonate that forms the skeletal structures of organisms, but it has relatively low preservation potential. Under ambient conditions and in the presence of water, aragonite transforms into calcite, the stable polymorph. Aragonite is also more soluble therefore, in water-permeable siliceous limestones (opokas) that are typical of Upper Cretaceous deposits of Poland and Ukraine, the primary aragonitic skeletons are either entirely dissolved and found as moulds and casts or transformed into secondary calcite, whereas the primary calcitic shells remain well preserved. Contrary to the common notion of the lack of aragonite in such porous carbonate deposits, we show that relics of aragonite can be preserved as a nacreous lining on cephalopod moulds or as thin, lenticular structures entrapped in neomorphic calcite. Based on the observed intermediate steps of aragonite alteration, we propose an extended model of nacre diagenesis. Among the originally aragonitic biota, only nautilids and ammonites have retained relics of pristine skeletons. Such selective preservation of only some aragonitic structures (nacre but not the prismatic aragonitic layers) points to the role of microstructural and biochemical differences between cephalopod shell layers that may set a threshold for the dissolution, dissolution/precipitation or preservation of original biomineral structures. [ABSTRACT FROM AUTHOR]

Background: Ukraine developed Europe's most severe HIV epidemic due to widespread transmission among persons who inject drugs (PWID). Since 2004, prevention has focused on key populations; antiretroviral therapy (ART) coverage has increased. Recent data show increases in reported HIV cases through 2011, especially attributed to sexual transmission, but also signs of potential epidemic slowing. We conducted a data triangulation exercise to better analyze available data and inform program implementation. Methods and Findings: We reviewed data for 2005 to 2012 from multiple sources, primarily national HIV case reporting and integrated biobehavioral surveillance (IBBS) studies among key populations. Annually reported HIV cases increased at a progressively slower rate through 2011 with recent increases only among older, more immunosuppressed individuals; cases decreased 2.7% in 2012. Among women <25 years of age, cases attributed to heterosexual transmission and HIV prevalence in antenatal screening declined after 2008. Reported cases among young PWID declined by three-fourths. In 2011, integrated biobehavioral surveillance demonstrated decreased HIV prevalence among young members of key populations compared with 2009. HIV infection among female sex workers (FSW) remains strongly associated with a personal history of injecting drug use (IDU). Conclusions: This analysis suggests that Ukraine's HIV epidemic has slowed, with decreasing reported cases and older cases predominating among those diagnosed. Recent decreases in cases and in prevalence support decreased incidence among young PWID and women. Trends among heterosexual men and men who have sex with men (MSM) are less clear; further study and enhanced MSM prevention are needed. FSW appear to have stable prevalence with risk strongly associated with IDU. Current trends suggest the Ukrainian epidemic can be contained with enhanced prevention among key populations and increased treatment access. [ABSTRACT FROM AUTHOR]

The 1986 accident at the Chernobyl nuclear power plant remains the most serious nuclear accident in history, and excess thyroid cancers, particularly among those exposed to releases of iodine-131 remain the best-documented sequelae. Failure to take dose-measurement error into account can lead to bias in assessments of dose-response slope. Although risks in the Ukrainian-US thyroid screening study have been previously evaluated, errors in dose assessments have not been addressed hitherto. Dose-response patterns were examined in a thyroid screening prevalence cohort of 13,127 persons aged <18 at the time of the accident who were resident in the most radioactively contaminated regions of Ukraine. We extended earlier analyses in this cohort by adjusting for dose error in the recently developed TD-10 dosimetry. Three methods of statistical correction, via two types of regression calibration, and Monte Carlo maximum-likelihood, were applied to the doses that can be derived from the ratio of thyroid activity to thyroid mass. The two components that make up this ratio have different types of error, Berkson error for thyroid mass and classical error for thyroid activity. The first regression-calibration method yielded estimates of excess odds ratio of 5.78 Gy−1 (95% CI 1.92, 27.04), about 7% higher than estimates unadjusted for dose error. The second regression-calibration method gave an excess odds ratio of 4.78 Gy−1 (95% CI 1.64, 19.69), about 11% lower than unadjusted analysis. The Monte Carlo maximum-likelihood method produced an excess odds ratio of 4.93 Gy−1 (95% CI 1.67, 19.90), about 8% lower than unadjusted analysis. There are borderline-significant (p = 0.101–0.112) indications of downward curvature in the dose response, allowing for which nearly doubled the low-dose linear coefficient. In conclusion, dose-error adjustment has comparatively modest effects on regression parameters, a consequence of the relatively small errors, of a mixture of Berkson and classical form, associated with thyroid dose assessment. [ABSTRACT FROM AUTHOR]

Background: The epidemics of incarceration, substance use disorders (SUDs), and infectious diseases are inextricably intertwined, especially in the Former Soviet Union (FSU). Few objective data documenting this relationship regionally are available. We therefore conducted a comprehensive, representative country-wide prison health survey in Ukraine, where one of the world’s most volatile HIV epidemics persists, in order to address HIV prevention and treatment needs. Methods: A nation-wide, multi-site randomly sampled biobehavioral health survey was conducted in four Ukrainian regions in 13 prisons among individuals being released within six months. After consent, participants underwent standardized health assessment surveys and serological testing for HIV, viral hepatitis, and syphilis. Results: Of the 402 participants (mean age = 31.9 years), 20.1% were female. Prevalence of HIV, HCV, HBV, and syphilis was 19.4% (95% CI = 15.5%–23.3%), 60.2% (95% CI = 55.1%–65.4%), 5.2% (95% CI = 3.3%–7.2%), and 10% (95% CI = 7.4%–13.2%), respectively, with regional differences observed; HIV prevalence in the south was 28.6%. Among the 78 HIV-infected inmates, 50.7% were unaware of their HIV status and 44 (56.4%) had CD4<350 cells/mL, of which only five (11%) antiretroviral-eligible inmates were receiving it. Nearly half of the participants (48.7%) reported pre-incarcertion drug injection, primarily of opioids, yet multiple substance use (31.6%) and alcohol use disorders (56.6%) were common and 40.3% met screening criteria for depression. Conclusions: This is the only such representative health study of prisoners in the FSU. This study has important implications for regional prevention and treatment because, unlike elsewhere, there is no recent evidence for reduction in HIV incidence and mortality in the region. The prevalence of infectious diseases and SUDs is high among this sample of prisoners transitioning to the community. It is critical to address pre- and post-release prevention and treatment needs with the development of linkage programs for the continuity of care in the community after release. [ABSTRACT FROM AUTHOR]

Background: Tobacco use has been identified as the single biggest cause of inequality in morbidity. The objective of this study is to examine the role of social determinants on current tobacco use in thirteen low-and-middle income countries. Methodology/Principal Findings: We used nationally representative data from the Global Adult Tobacco Survey (GATS) conducted during 2008-2010 in 13 low-and-middle income countries: Bangladesh, China, Egypt, India, Mexico, Philippines, Poland, Russian Federation, Thailand, Turkey, Ukraine, Uruguay, and Viet Nam. These surveys provided information on 209,027 respondent's aged 15 years and above and the country datasets were analyzed individually for estimating current tobacco use across various socio-demographic factors (gender, age, place of residence, education, wealth index, and knowledge on harmful effects of smoking). Multiple logistic regression analysis was used to predict the impact of these determinants on current tobacco use status. Current tobacco use was defined as current smoking or use of smokeless tobacco, either daily or occasionally. Former smokers were excluded from the analysis. Adjusted odds ratios for current tobacco use after controlling other cofactors, was significantly higher for males across all countries and for urban areas in eight of the 13 countries. For educational level, the trend was significant in Bangladesh, Egypt, India, Philippines and Thailand demonstrating decreasing prevalence of tobacco use with increasing levels of education. For wealth index, the trend of decreasing prevalence of tobacco use with increasing wealth was significant for Bangladesh, India, Philippines, Thailand, Turkey, Ukraine, Uruguay and Viet Nam. The trend of decreasing prevalence with increasing levels of knowledge on harmful effects of smoking was significant in China, India, Philippines, Poland, Russian Federation, Thailand, Ukraine and Viet Nam. Conclusions/Significance: These findings demonstrate a significant but varied role of social determinants on current tobacco use within and across countries. [ABSTRACT FROM AUTHOR]

Methods of classification using transcriptome analysis for case-by-case tumor diagnosis could be limited by tumor heterogeneity and masked information in the gene expression profiles, especially as the number of tumors is small. We propose a new strategy, EMts_2PCA, based on: 1) The identification of a gene expression signature with a great potential for discriminating subgroups of tumors (EMts stage), which includes: a) a learning step, based on an expectation-maximization (EM) algorithm, to select sets of candidate genes whose expressions discriminate two subgroups, b) a training step to select from the sets of candidate genes those with the highest potential to classify training tumors, c) the compilation of genes selected during the training step, and standardization of their levels of expression to finalize the signature. 2) The predictive classification of independent prospective tumors, according to the two subgroups of interest, by the definition of a validation space based on a two-step principal component analysis (2PCA). The present method was evaluated by classifying three series of tumors and its robustness, in terms of tumor clustering and prediction, was further compared with that of three classification methods (Gene expression bar code, Top-scoring pair(s) and a PCA-based method). Results showed that EMts_2PCA was very efficient in tumor classification and prediction, with scores always better that those obtained by the most common methods of tumor clustering. Specifically, EMts_2PCA permitted identification of highly discriminating molecular signatures to differentiate post-Chernobyl thyroid or post-radiotherapy breast tumors from their sporadic counterparts that were previously unsuccessfully classified or classified with errors. [ABSTRACT FROM AUTHOR]