Alterations of Na, K and Rb concentrations in Mycenaean pottery and a proposed explanation using X-ray diffraction

One of the most important reference groups for Mycenaean pottery is the Mycenae/Berbati (MB). In several studies, a second group has been identified (MBKR). The chemical compositions were similar to MB, but with important differences in the Na, K and Rb contents. The present study suggests that these differences are due to selective alteration and contamination processes that are indirectly determined by the original firing temperature. Therefore, groups MB and MBKR should be considered as a single reference group

Standardisation of elemental analytical techniques applied to provenance studies of archaeological ceramics: an inter laboratory calibration study

Chemical analysis is a well-established procedure for the provenancing of archaeological ceramics. Various analytical techniques are routinely used and large amounts of data have been accumulated so far in data banks. However, in order to exchange results obtained by different laboratories, the respective analytical procedures need to be tested in terms of their inter-comparability. In this study, the schemes of analysis used in four laboratories that are involved in archaeological pottery studies on a routine basis were compared. The techniques investigated were neutron activation analysis (NAA), X-ray fluorescence analysis (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). For this comparison series of measurements on different geological standard reference materials (SRM) were carried out and the results were statistically evaluated. An attempt was also made towards the establishment of calibration factors between pairs of analytical setups in order to smooth the systematic differences among the results

Correction to "New Measurements of the Apparent Thermal Conductivity of Nanofluids and Investigation of Their Heat Transfer Capabilities"

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Non-destructive characterisation and classification of ceramic artefacts using pEDXRF and statistical pattern recognition

Background: Portable energy dispersive X-ray fluorescence (pEDXRF) spectrometry analysis was applied for the characterisation of archaeological ceramic findings from three Neolithic sites in Serbia. Two dimension reduction techniques, principal component analysis (PCA) and scattering matrices-based dimension reduction were used to examine the possible classification of those findings, and to extract the most discriminant features. Results: A decision-making procedure is proposed, whose goal is to classify unknown ceramic findings based on their elemental compositions derived by pEDXRF spectrometry. As a major part of decision-making procedure, the possibilities of two dimension reduction methods were tested. Scattering matrices-based dimension reduction was found to be the more efficient method for the purpose. Linear classifiers designed based on the desired output allowed for 7 of 8 unknown samples from the test set to be correctly classified. Conclusions: Based on the results, the conclusion is that despite the constraints typical of the applied analytical technique, the elemental composition can be considered as viable information in provenience studies. With a fully-developed procedure, ceramic artefacts can be classified based on their elemental composition and well-known provenance

THE COMMUNICATION POLICY OF INTERNATIONAL ORGANIZATIONS IN GREECE ON THE REFUGEE ISSUE. THE CASE OF THE HIGH COMMISSIONER (UNHCR) IN GREECE

The phenomenon of refugee flows originates in antiquity, but in recent years the intensity of the phenomenon makes it a major issue of the 21st century. In this context, International Organizations play a key and decisive role in the management of migration flows, as well as in the implementation of support and integration policies for vulnerable groups. They also aim to inform and sensitize the citizens of the host countries worldwide. Their communication strategy aims to highlight the main problems faced by specific migration groups. The Information and Communication Technologies (ICT) and social media, such as Facebook, YouTube and Instagram are some of the media that international organizations such as the UN High Commission (UNHCR) use in their communication strategy. Over the years and since its operation the High Commissioner of the UN used different channels of communication in order to put their message across. Due to the magnitude of migration flows and the role that the UNHCR plays in Greece, the local branch was investigated. The purpose of this article is a) to explore the perceptions of people who live in Greece and the extent to which these perceptions can be influenced by the communication policy of the UN High Commission in Greece and b) to explore the communication channels that UNHCR ustilises the most and which of them has the highest impact on citizens and for which reasons. The survey was conducted with a structured questionnaire which was accessible via the internet. The questionnaire was completed by 1000 respondents. Data analysis shows that respondents believe that organisations such as UNHCR should utilize social media in order to make widely known their vision and their actions as well as in order to raise public awareness about migration. Facebook rates highest in respondents’ preferences in social media followed by Instagram, YouTube and Twitter. Additionally, respondents stated that they trust more an international organization with an active participation on social media. The research concludes that strategic communication, advertising, and dissemination of good practices are the most effective methods for transforming perceptions, attitudes, and behaviours of the citizens. The example of UNHCR - Greece using Facebook, Youtube and Twitter is common with other international organisations such as International Organization of Migration (IOM), UNICEF-Greece and other national NGOs. The results show that citizens better understand the vision and goals of the organizations but are hesitant to make online donations or participate in voluntary actions

Alterations of Na, K and Rb concentrations in Mycenaean pottery and a proposed explanation using X-ray diffraction

One of the most important reference groups for Mycenaean pottery is the Mycenae/Berbati (MB). In several studies, a second group has been identified (MBKR). The chemical compositions were similar to MB, but with important differences in the Na, K and Rb contents. The present study suggests that these differences are due to selective alteration and contamination processes that are indirectly determined by the original firing temperature. Therefore, groups MB and MBKR should be considered as a single reference group

Assessment of dissolution techniques for the analysis of ceramic samples by plasma spectrometry

In this study, 13 ceramic samples were subjected to dissolution using three different procedures: (a) acid attack in open PTFE vessels with a mixture of HF-HClO4, (b) fusion of the sample with lithium metaborate and (c) microwave digestion in PTFE bombs. The samples used in the study had been previously analyzed by neutron activation analysis (NAA), X-ray fluorescence (XRF) and X-ray diffraction (XRD) and they cover a wide range of ceramics fired in different atmospheres and temperatures as well as different mineralogical and chemical compositions. The effectiveness of each procedure is evaluated in terms of its ability to dissolve the various mineralogical phases of the samples, of the number of elements that can be determined and of the time needed for the whole scheme of analysis to be completed

Glucocorticoid receptor alpha and beta isoforms are not mutated in bipolar affective disorder

The periodically hyperactive hypothalamic-pituitary-adrenal (HPA) axis in bipolar affective disorders, as well as the reported changes in the binding characteristics of the glucocorticoid receptor (GR), suggest the possible involvement of the GR in the aetiopathology of this disease. This was investigated by screening the coding sequences of both GR isoforms, GR alpha and GR beta, for the presence of mutations. As a genetic predisposition has been implicated, we included in this study bipolar patients who were siblings. By RT-PCR of peripheral blood mononuclear cells from patients suffering from bipolar illness, using primers spanning the whole length of the GR alpha and GR beta coding region and subsequent agarose gel electrophoresis, heteroduplex and sequence analyses, no GR mutations could be detected. Since glucocorticoid receptor activity can be modulated by agents other than the respective ligand leg by growth factors, cytokines and stress signals), our results favor derangements in the modulation of GR activity by such agents and not in the primary structure of the receptor as aetiopathologic factors of bipolar disease