Singing a New Song? Transnational Migration, Methodological Nationalism and Cosmopolitan Perspectives

The question posed by this article is how all of us - scholars, musicians, citizens of the world can step out of the migrant/native divide and still leave room to study and theorize creative processes that bring together the intertwining of cultural influences. How can we discard a concept of hybridity with its implications of a prior state of native purity and address the ongoing mutual interactions that unfold within migration processes? This is an ever pressing question for cultural theory in a world in which there is widespread migration and a cyberspace environment of multiple interconnections. Migration provides a base for theorizing cultural processes that extend beyond the specificity of people crossing borders. In order to begin answering this question it is useful to ask when and why do we see a migrant/ foreigner vs. native divide in the first place. This divide reflects and reinforces a tendency in various disciplines to equate nation-state boundaries with the concept of society. In the first section of this article, we will explore the nature and implications of methodological nationalism and place it within a historical context. In its stead we will offer what Glick Schiller has called “a global power perspective on migration” (Glick Schiller, 2009, 2010b). In the second part of the paper we will apply this perspective to case studies of the transnational social field of musical creation that stretches between Europe and localities of artistic production in Africa. Focusing on the movements and interconnections of musicians of Malagasy origin, we will illustrate the ways in which transnational networking can give rise to substantial ‘transcultural capital’, (Kiwan and Meinhof, 2011; Meinhof, 2009; Meinhof and Triandafyllidou, 2006b) and thus underpin the professionalization of some artists, but can also reflect the inequalities and multiple pressures for authenticity in the world music market

Zur Methode der Bedarfsbestimmung im kommunalen Finanzausgleich Sachsens

ZUR METHODE DER BEDARFSBESTIMMUNG IM KOMMUNALEN FINANZAUSGLEICH SACHSENS Zur Methode der Bedarfsbestimmung im kommunalen Finanzausgleich Sachsens / Hardt, Ulrike (Rights reserved) ( -

The solubilisation of boar sperm membranes by different detergents - a microscopic, MALDI-TOF MS, 31P NMR and PAGE study on membrane lysis, extraction efficiency, lipid and protein composition

<p>Abstract</p> <p>Background</p> <p>Detergents are often used to isolate proteins, lipids as well as "detergent-resistant membrane domains" (DRMs) from cells. Different detergents affect different membrane structures according to their physico-chemical properties. However, the effects of different detergents on membrane lysis of boar spermatozoa and the lipid composition of DRMs prepared from the affected sperm membranes have not been investigated so far.</p> <p>Results</p> <p>Spermatozoa were treated with the selected detergents Pluronic F-127, sodium cholate, CHAPS, Tween 20, Triton X-100 and Brij 96V. Different patterns of membrane disintegration were observed by light and electron microscopy. In accordance with microscopic data, different amounts of lipids and proteins were released from the cells by the different detergents. The biochemical methods to assay the phosphorus and cholesterol contents as well as ³¹P NMR to determine the phospholipids were not influenced by the presence of detergents since comparable amounts of lipids were detected in the organic extracts from whole cell suspensions after exposure to each detergent. However, matrix-assisted laser desorption and ionization time-of-flight mass spectrometry applied to identify phospholipids was essentially disturbed by the presence of detergents which exerted particular suppression effects on signal intensities. After separation of the membrane fractions released by detergents on a sucrose gradient only Triton X-100 and sodium cholate produced sharp turbid DRM bands. Only membrane solubilisation by Triton X-100 leads to an enrichment of cholesterol, sphingomyelin, phosphatidylinositol and phosphatidylethanolamine in a visible DRM band accompanied by a selective accumulation of proteins.</p> <p>Conclusion</p> <p>The boar sperm membranes are solubilised to a different extent by the used detergents. Particularly, the very unique DRMs isolated after Triton X-100 exposure are interesting candidates for further studies regarding the architecture of sperm.</p

Seminal lipid profiling and antioxidant capacity : a species comparison

On their way to the oocyte, sperm cells are subjected to oxidative stress, which may trigger the oxidation of phospholipids (PL). Applying MALDI-TOF MS, HPTLC and ESI-IT MS, we comparatively analyzed the PL compositions of semen and blood of species differing in their reproductive systems and types of nutrition (bull, boar, stallion, lion and man) with regard to the sensitivity to oxidation as well as the accumulation of harmful lyso-PL (LPL), transient products of lipid oxidation. In addition, the protective capacity of seminal fluid (SF) was also examined. The PL composition of erythrocytes and blood plasma is similar across the species, while pronounced differences exist for sperm and SF. Since the blood function is largely conserved across mammalian species, but the reproductive systems may vary in many aspects, the obtained results suggest that the PL composition is not determined by the type of nutrition, but by the relatedness of species and by functional requirements of cell membranes such as fluidity. Sperm motion and fertilization of oocytes require a rather flexible membrane, which is accomplished by significant moieties of unsaturated fatty acyl residues in sperm lipids of most species, but implies a higher risk of oxidation. Due to a high content of plasmalogens (alkenyl ether lipids), bull sperm are most susceptible to oxidation. Our data indicate that bull sperm possess the most effective protective power in SF. Obviously, a co-evolution of PL composition and protective mechanisms has occurred in semen and is related to the reproductive characteristics. Although the protective capacity in human SF seems well developed, we recorded the most pronounced individual contaminations with LPL in human semen. Probably, massive oxidative challenges related to lifestyle factors interfere with natural conditions.SUPPLEMENTARY MATERIAL: S1 Fig. ESI spectra of lysophosphatidylcholine (LPC) fractions from boar, bull, stallion, lion and human samples.S2 Fig. ESI spectra of sphingomyelin (SM) fractions from boar, bull, stallion, lion and human samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. SM fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the positive ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S2 Table. https://doi.org/10.1371/journal.pone.0264675.s002S3 Fig. ESI spectra of phosphatidylcholine (PC) fractions from boar, bull, stallion, lion and human samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PC fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the positive ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S3 Table. https://doi.org/10.1371/journal.pone.0264675.s003S4 Fig. ESI spectra of phosphatidylinositol (PI) fractions from boar, bull, stallion and human lipid samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PI fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the negative ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S4 Table. https://doi.org/10.1371/journal.pone.0264675.s004S5 Fig. ESI spectra of phosphatidylethanolamine (PE) fractions from boar, bull and stallion samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PE fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the negative ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S5 Table. https://doi.org/10.1371/journal.pone.0264675.s005S6 Fig. ESI spectra of phosphatidylethanolamine (PE) fractions from lion and human samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PE fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the negative ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S5 Table. https://doi.org/10.1371/journal.pone.0264675.s006S7 Fig. Hydrolysis of selected seminal fluid samples over time. The plots of hydrolysis measurements from boar and stallion seminal fluid were fitted by a linear curve (f(x) = a + b×x) and the plots from bull, lion and human were fitted by an exponential growth to a maximum (f(x) = a×e-b×x). Due to these different courses of the hydrolysis reaction between the species, the absolute hydrolysis at a given time point (10 min) was used to compare the mean values of the investigated individuals between the species (see Table 2 of the main text). https://doi.org/10.1371/journal.pone.0264675.s007S8 Fig. Effect of artificial LPC on boar sperm. Beltsville Thawing Solution (BTS, Minitüb GmbH)-diluted boar semen (20 × 106 sperm/ml) was mixed with 20 μM lysophosphatidylcholine (LPC 16:0, Avanti Polar Lipids®, No 855675C). After incubation at 38°C for 30 min, the ratios of total motility (blank boxes) and sperm with an intact acrosome (striped boxes) were analyzed. The lipid extract of washed sperm of this experiment was analyzed by MALDI-TOF MS and the ratio of LPC to total GPC was calculated (for details see Material and Methods of the main text). Incubation with 20 μM LPC led to 2.4 ± 3.6% inserted LPC in sperm cell membranes. Significant differences in total motility and the percentage of sperm with an intact acrosome between the incubation with 20 μM LPC and controls are marked by asterisks (P = 0.006 and 0.003, respectively, Wilcoxon signed-rank test, n = 11). https://doi.org/10.1371/journal.pone.0264675.s008S9 Fig. Original TLC pictures. Lipid extracts were separated on normal phase high performance thin-layer chromatography (HPTLC) plates with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). BP–blood plasma, SF–seminal fluid, st.–lipid standard mixture made of LPC16:0, SM16:0, PC16:0/18:1, PA 16:0/18:1, PI 16:1/18:1, PE 16:0/18:1, PG 16:0/18:1 (bottom up). https://doi.org/10.1371/journal.pone.0264675.s009S1 Table. Assignment of signals detected in ESI spectra from lysophosphatidylcholine (LPC) spots. https://doi.org/10.1371/journal.pone.0264675.s010S2 Table. Assignment of signals detected in ESI spectra from sphingomyelin (SM) spots. n.a.—not assigned. https://doi.org/10.1371/journal.pone.0264675.s011S3 Table. Assignment of signals detected in ESI spectra from phosphatidylcholine (PC) spots. https://doi.org/10.1371/journal.pone.0264675.s012S4 Table. Assignment of signals detected in ESI spectra from phosphatidylinositol (PI) spots. https://doi.org/10.1371/journal.pone.0264675.s013S5 Table. Assignment of signals detected in ESI spectra from phosphatidylethanolamine (PE) spots. https://doi.org/10.1371/journal.pone.0264675.s014The German Research Council.http://www.plosone.orgdm2022Veterinary Tropical Disease

Arzneimittelrückstände in Trinkwasser und Gewässern. Endbericht zum TA-Projekt

Vor dem Hintergrund eines stetig steigenden Verbrauchs von Arzneimitteln gibt der Bericht einen Überblick über den Wissensstand zu Mengen, Qualitäten und Wirkungen der Mikroverunreinigungen auf Mensch und Umwelt. Es werden Vorschläge zur Vermeidung der Verunreinigungen zusammengetragen und Wissenslücken und mögliche Handlungsstrategien zur Verringerung der Risiken durch Arzneimittelrückstände im Wasser aufgezeigt. Geboten wird eine Übersicht dazu, welche Human- und Tierarzneimittel in welchen Quantitäten in Deutschland verwendet werden und nach aktuellem Kenntnisstand ihrer Menge oder ihrer Wirkung nach in human- und ökotoxikologischer Hinsicht relevant sind. Zudem wird der Zielkonflikt zwischen individuellen Ansprüchen auf Heilung durch Medikamente einerseits und den potenziellen Risiken von Arzneimittelrückständen für die allgemeine Gesundheit und Umwelt andererseits analysiert. Weil das Eintreten negativer Effekte unsicher ist, wird diskutiert, welche Anhaltspunkte und Hilfestellung das Vorsorgeprinzip bei der Bewältigung dieser Konflikte leisten kann. Systematisch werden Überlegungen zu technischen Maßnahmen und regulatorischen Strategien zur Verringerung der Risiken von Arzneimittelrückständen in Gewässern vorgestellt, darunter die derzeit intensiv diskutierte vierte Reinigungsstufe von Kläranlagen, die Mikroverunreinigungen zu großen Teilen aus Abwässern entfernen kann. Stärker an der Quelle der Verunreinigung setzen regulatorische Maßnahmen an, z. B. im Zusammenhang mit dem Prozess der Arzneimittelzulassung, oder Informationsmaßnahmen, die bei Verbraucherinnen und Verbrauchern, Ärzteschaft und Apotheken ein Problembewusstsein zu schaffen versuchen. Diskutiert wird, wie die verschiedenen Maßnahmenoptionen sinnvoll miteinander kombiniert und in eine umfassende Strategie eingebettet werden können und welche Rolle bei der Strategiefindung, -entscheidung und -umsetzung den verschiedenen staatlichen und privaten gesellschaftlichen Akteuren zukommt. Inhalt Zusammenfassung 9 1 Einleitung 17 2 Mengenanalyse und Trends von Pharmakarückständen in Gewässern in Deutschland 25 2.1 Verbrauchsmengen von Human- und Tierarzneimitteln 25 2.1.1 Humanarzneimittel 26 2.1.2 Tierarzneimittel 35 2.2 Die Eintragswege der Arzneistoffe in Oberflächengewässer und ins Grundwasser 41 2.2.1 Haupteintragspfade von Arzneimittelrückständen in Gewässer 42 2.2.2 Humanarzneimittel 43 2.2.3 Tierarzneimittel 45 2.3 Nachweise von Arzneimitteln in Trinkwasser und Gewässern 45 2.3.1 Humanarzneimittel 46 2.3.2 Tierarzneimittel 50 2.4 Fazit 51 3 Auswirkungen von Arzneimittelrückständen auf Gesundheit und Umwelt 53 3.1 Methodische Ansätze zur Vorhersage und Bewertung potenziell negativer Auswirkungen 54 3.1.1 Grundbegriffe der Toxikologie 54 3.1.2 Das PEC/PNEC-Risikobewertungskonzept 57 3.1.3 Methoden zur Bewertung von Kombinationswirkungen 60 3.2 Auswirkungen von Arzneimittelrückständen auf die menschliche Gesundheit 63 3.2.1 Akute Gesundheitsgefährdungen durch Trinkwasser 63 3.2.2 Langzeit- und Niedrigdosiswirkungen 65 3.2.3 Antibiotika und Antibiotikaresistenzen 66 3.2.4 Hormonelle Wirkungen 68 3.2.5 Schäden der Erbsubstanz oder von Embryonen durch Zytostatika 70 3.2.6 Neurotoxische Wirkungen 71 3.2.7 Kombinationswirkungen 72 3.3 Auswirkungen von Arzneimittelrückständen auf die Umwelt 73 3.3.1 Akute Wirkungen 74 3.3.2 Langzeit- und Niedrigdosiswirkungen 76 3.3.3 Hormonelle Wirkungen 77 3.3.4 Neurotoxische Wirkungen 78 3.3.5 Umweltwirkungen von Zytostatika 79 3.3.6 Kombinationswirkungen 80 3.4 Fazit 82 4 Das Vorsorgeprinzip: gesellschaftliche Zielkonflikte zwischen Gesundheit, Tierwohl und Umweltschutz 85 4.1 Das Vorsorgeprinzip 86 4.1.1 Handeln unter Unsicherheit und Nichtwissen 86 4.1.2 Vorsorgeprinzip, Nichtwissen und Evidenz 89 4.1.3 Die Verankerung des Vorsorgeprinzips im Recht 90 4.1.4 Schlussfolgerungen für das Problem der Arzneimittelrückstände in Trinkwasser und Gewässern – Strategien zur Beschaffung von Informationen 92 4.2 Relevante Schutzgüter 94 4.2.1 Menschliche Gesundheit 95 4.2.2 Tiergesundheit 95 4.2.3 Umwelt 96 4.2.4 Trinkwasser 97 4.2.5 Konflikte zwischen Schutzgütern 98 4.3 Der rechtliche Rahmen für die Zulassung und das Inverkehrbringen von Medikamenten 99 4.3.1 Bewertung und Berücksichtigung von Umweltrisiken – Humanarzneimittel 99 4.3.2 Bewertung und Berücksichtigung von Umweltrisiken – Tierarzneimittel 102 4.3.3 Regelungen im Gewässer-, Grund- und Trinkwasserschutz 105 4.4 Arzneimittelrückstände im Wasser im medialen Diskurs 107 4.4.1 Entwicklung und Ton der Berichterstattung 109 4.4.2 Inhalte der Berichterstattung 110 4.5 Fazit 114 5 Maßnahmen zur Verringerung der Risiken durch Arzneimittelrückstände im Wasser 117 5.1 Vorgehen bei der Beschreibung und der vergleichenden Bewertung der Maßnahmen 117 5.2 Maßnahmen in der Wasserwirtschaft 120 5.2.1 W1: Verbesserte kommunale Abwasserbehandlung durch eine vierte Reinigungsstufe 121 5.2.2 W2: Dezentrale Behandlung von Abwässern aus Krankenhäusern und anderen Gesundheitseinrichtungen 130 5.2.3 W3: Vermeidung der Einleitung von Rückständen aus der Produktion von Arzneimitteln 133 5.2.4 W4: Regulierungen im Wasserrecht und verstärktes Monitoring von Arzneistoffen in Grundwasser und Gewässern 135 5.3 Maßnahmen im Gesundheitssystem 138 5.3.1 G1: a) Berücksichtigung von Umweltrisiken bei der Zulassung von Humanarzneimitteln und b) Erweiterung des Pharmakovigilanzsystems um ein umfassendes Umweltinformationssystem 138 5.3.2 G2: Green Pharmacy – umweltfreundlichere Arzneimittel 142 5.3.3 G3: Vermeidung von Arzneimittelbedarf durch Gesundheitsförderung und Prävention 144 5.3.4 G4: Sensibilisierung von Ärztinnen und Ärzten sowie Patientinnen und Patienten für die Umweltwirkungen von Arzneimittelrückständen 146 5.3.5 G5: Verschreibung angepasster Verbrauchsmengen 148 5.3.6 G6: Einführung eines Umweltklassifikationssystems für Arzneistoffe und Medikamente 150 5.3.7 G7: Einheitlich geregelte, klar kommunizierte und sichere Entsorgung von Altmedikamenten 153 5.3.8 G8: Sammlung von Röntgenkontrastmitteln in Urinsammelbehältern 155 5.4 Maßnahmen in Landwirtschaft und Tierhaltung 158 5.4.1 L1: Einführung eines Systems zur Bestimmung von Verbrauchsmengen 160 5.4.2 L2: Erweiterung des Pharmakovigilanzsystems für Tierarzneimittel um ein umfassendes Umweltinformationssystem 161 5.4.3 L3: Aus- und Weiterbildungsangebote sowie Informationskampagnen zu Umweltaspekten des Einsatzes von Tierarzneimitteln 162 5.4.4 L4: Weitere Maßnahmen zur Minderung der Einträge von Tierarzneimitteln und zur Entlastung der Umwelt 165 6 Strategien zur Verringerung der Risiken durch Arzneimittelrückstände 169 6.1 Vorsorgeprinzip und Handlungsbedarf – was ist heute schon zu tun? 170 6.2 Der Zusammenhang von Arzneimittelrückständen und weiteren Mikroverunreinigungen 172 6.3 Akteure der Maßnahmenumsetzung 173 6.3.1 Staatliche Akteure 173 6.3.2 Nichtstaatliche Akteure 175 6.4 Maßnahmenkombinationen zur Reduktion und Vorbeugung von Arzneistoffen in Trinkwasser, Grundwasser und Gewässern 175 6.5 Finanzierung einer Strategie gegen Arzneimittelrückstände und andere Mikroverunreinigungen im Wasser 180 6.6 Fazit 185 7 Literatur 187 7.1 In Auftrag gegebene Gutachten 187 7.2 Weitere Literatur 187 8 Anhang 207 8.1 Abbildungen 207 8.2 Tabellen 20

Interplay between steps and oxygen vacancies on curved TiO2(110)

Trabajo presentado al Symposium on Surface Science (3S), celebrado en St. Christoph am Arlberg (Austria) del 21 al 27 de febrero de 2016.We acknowledge financial support from the Spanish Ministry of Economy (grant MAT2013-46593-C6-4-P and MAT2013-46593-C6-2-P) and the Basque Government (grant IT621-13 and IT756-13), the ERC Advanced Grant “OxideSurfaces”., and the Marie Curie ITN “THINFACE”.Peer reviewe

Global CO2 emissions from dry inland waters share common drivers across ecosystems

Many inland waters exhibit complete or partial desiccation, or have vanished due to global change, exposing sediments to the atmosphere. Yet, data on carbon dioxide (CO2) emissions from these sediments are too scarce to upscale emissions for global estimates or to understand their fundamental drivers. Here, we present the results of a global survey covering 196 dry inland waters across diverse ecosystem types and climate zones. We show that their CO2 emissions share fundamental drivers and constitute a substantial fraction of the carbon cycled by inland waters. CO2 emissions were consistent across ecosystem types and climate zones, with local characteristics explaining much of the variability. Accounting for such emissions increases global estimates of carbon emissions from inland waters by 6% (~0.12 Pg C y−1). Our results indicate that emissions from dry inland waters represent a significant and likely increasing component of the inland waters carbon cycle

Cirrus clouds

Andrew J. Heymsfield, Martina Kramer, Anna Luebke, Phil Brown, Daniel J. Cziczo, Charmaine Franklin, Ulrike Lohmann, Greg McFarquhar, Zbigniew Ulanowski and Kristof Van Trich, American Meteorological Society , January 2017, this article has been published in final form at DOI: http://dx.doi.org/10.1175/AMSMONOGRAPHS-D-16-0010.1 Published by AMS Publications © 2017 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (http://www.ametsoc.org/PUBSCopyrightPolicy).The goal of this article is to synthesize information about what is now known about one of the three main types of clouds, cirrus, and to identify areas where more knowledge is needed. Cirrus clouds, composed of ice particles, form primarily in the upper troposphere, where temperatures are generally below -30°C. Satellite observations show that the maximum-occurrence frequency of cirrus is near the tropics, with a large latitudinal movement seasonally. In-situ measurements obtained over a wide range of cloud types, formation mechanisms, temperatures, and geographical locations indicate that the ice water content and particle size generally decrease with decreasing temperature, whereas the ice particle concentration is nearly constant or increase slightly with decreasing temperature. High ice concentrations, sometimes observed in strong updrafts , results from homogeneous nucleation. The satellite-based and in-situ measurements indicate that cirrus ice crystals typically depart from the simple, idealized geometry for smooth hexagonal shapes, indicating complexity and/or surface roughness. Their shapes significantly impact cirrus radiative properties and feedbacks to climate. Cirrus clouds, one of the most uncertain components of general circulation models (GCM), pose one of the greatest challenges in predicting the rate and geographical pattern of climate change. Improved measurements of the properties and size distributions and surface structure of small ice crystals — about 20 μm, and identifying the dominant ice nucleation process — heterogeneous versus homogeneous ice nucleation, under different cloud dynamical forcings, will lead to a better representation of their properties in GCM and in modeling their current and future effects on climate.Peer reviewe