The glacial cycles and cosmic rays

The cause of the glacial cycles remains a mystery. The origin is widely accepted to be astronomical since paleoclimatic archives contain strong spectral components that match the frequencies of Earth's orbital modulation. Milankovitch insolation theory contains similar frequencies and has become established as the standard model of the glacial cycles. However, high precision paleoclimatic data have revealed serious discrepancies with the Milankovitch model that fundamentally challenge its validity and re-open the question of what causes the glacial cycles. We propose here that the ice ages are initially driven not by insolation cycles but by cosmic ray changes, probably through their effect on clouds. This conclusion is based on a wide range of evidence, including results presented here on speleothem growth in caves in Austria and Oman, and on a record of cosmic ray flux over the past 220 kyr obtained from the 10Be composition of deep-ocean sediments

Drawings on Parchment and Paper of Medieval Italian Notaries (12th-15th Centuries)

Il contributo ha lo scopo di portare all\u2019attenzione l\u2019ampia presenza di disegni e schizzi tracciati su pergamena e carta dai notai medievali italiani. Dagli esempi \u2013 differenti per area geografica, altezza cronologica e tipologia \u2013 risulta evidente che il know-how dei notai si esprimeva non solo attraverso parole e numeri, ma anche mediante segni e disegni pi\uf9 o meno estemporanei e funzionali alla propria attivit\ue0. Infatti se gi\ue0 nella routine quotidiana, i notai dimostravano capacita` grafiche tracciando segni speciali di autenticazione e disegnando a supporto di specifiche esigenze documentarie, non va dimenticato che oltre a queste manifestazioni grafico-artistiche strettamente connesse all\u2019esercizio della propria professione, i notai spesso tracciavano sulle coperte di legatura, sui fogli di guardia e sulle pagine inutilizzate dei propri registri pergamenacei e cartacei disegni estemporanei, frutto della loro cultura poliedrica nonch\ue9 dei loro sentimenti pi\uf9 intimi

Sea-level change over the northern European continental shelf due to atmospheric and oceanic contributions

Global mean sea level (GMSL) is a key indicator of climate change as it comprises information on different components of the climate system. However, despite its importance for climate and society, GMSL cannot be used for coastal adaptation policies because regional sea-level variations can significantly depart from the global average. Providing accurate estimates of sea-level rise is therefore one of the most important scientific issues that climate change poses, with a large impact for the human population as it is recognized as the main driver for changes in sea-level extremes, influencing the non-linear interactions between processes acting over different temporal and spatial scales in coastal areas. This thesis addresses different aspects of the sea-level variability over the northern European continental shelf. Paper I uses gridded satellite altimetry data and adopts the jet clusters perspective of the winter-time atmospheric variability over the North Atlantic to reassess the contribution of local winds to the sea-level variability over the northern European continental shelf. By using the jet clusters, Paper I distinguishes itself from the existing literature since the jet clusters provide a physical description of the atmospheric variability in the North Atlantic. Papers II and III focus on the steric and manometric components of the sea-level over the Norwegian section of the northern European continental shelf and on the sea-level observing system in the region. Paper II first evaluates a coastal altimetry dataset, reprocessed with the ALES-retracker, against the Norwegian set of tide gauges. After showing a good agreement between the two, it exploits the coastal satellite altimetry dataset to reassess the steric component of the sea level over the Norwegian shelf: the paper finds that the estimates of the steric component of the sea-level do not depend much on the choice of the tide gauges or satellite altimetry. Paper III evaluates the sea-level observing system along the Norwegian coast by assessing the ability of a satellite gravimetry mission, the Gravity Recovery and Climate Experiment (GRACE), and of a combination of satellite altimetry and hydrography to monitor manometric sea-level variations in the region. It then investigates the open-ocean contribution to the inter-annual manometric sea-level variations along the coast of Norway. It shows that, while commonly considered not reliable in the coastal region, GRACE captures the main features of the manometric sea-level change in the area, which on interannual and longer time scales can be attributed to along-slope winds and open-ocean steric changes. Therefore, GRACE can be used to analyze the manometric sea-level variability, such as in sea-level budget studies, especially in those areas of the coastal ocean where in-situ measurements are sparse. Overall, by focusing on the northern European continental shelf due to its well developed sea-level observing system, this thesis has demonstrated the potential of remote sensing observations in improving our understanding of sea-level variability and change in the coastal ocean.Doktorgradsavhandlin

From the Atlantic to the Pacific: Maruja Mallo in Exile

Maruja Mallo\u27s life (1902-1995) and art represent one woman\u27s odyssey from the European vanguards to political commitment during the Spanish Republic (1931-1939) and finally to a unique transcendent art form after her wrenching exile from Spain and her residence in Latin America from 1937 to 1965. In her early career she was a leader among the avant-garde painters when few Spanish women were recognized as creative artists. In Latin America, her work diverged radically from European avant-garde trends and from her ideologically oriented subject matter of the 1930s; Mallo not only reflects the impact of her discovery of the Pacific Ocean and her newfound zest for life, but also clearly defines a new language that celebrates the female body and female sexuality. This essay traces Mallo\u27s personal and artistic journey from Spain to Latin America and back

Ventilation and cave air PCO2 in the Bunker-Emst Cave System (NW Germany): implications for speleothem proxy data

Cave air pCO2 (carbon dioxide partial pressure) is, along with drip rate, one of the most important factors controlling speleothem carbonate precipitation. As a consequence, pCO2 has an indirect but important control on speleothem proxy data (e.g., elemental concentrations, isotopic values). The CO2 concentration of cave air depends on CO2 source(s) and productivity, CO2 transport through the epikarst and karst zone, and cave air ventilation. To assess ventilation patterns in the Bunker-Emst Cave (BEC) System, we monitored the pCO2 value approximately 100 m from the lower entrance (Bunker Cave) at bi-hourly resolution between April 2012 and February 2014. The two entrances of the BEC system were artificially opened between 1860?1863 (Emst Cave) and 1926 (Bunker Cave). Near-atmospheric minimum pCO2dynamics of 408 ppmv are measured in winter, and up to 811 ppmv are recorded in summer. Outside air contributes the highest proportion to cave air CO2, while soil, and possibly also ground air, provide a far smaller proportion throughout the whole year. Cave air pCO2 correlates positively with the temperature difference between surface and cave air during summer and negatively in winter, with no clear pattern for spring and autumn. Dynamic ventilation is driven by temperature and resulting density differences between cave and surface air. In summer, warm atmospheric air is entrained through the upper cave entrance where it cools. With increasing density, the cooled air flows toward the lower entrance. In winter, this pattern is reversed, due to cold, atmospheric air entering the cave via the lower entrance, while relatively warm cave air rises and exits the cave via the upper entrance. The situation is further modulated by preferential south-southwestern winds that point directly on both cave entrances. Thus, cave ventilation is frequently disturbed, especially during periods with higher wind speed. Modern ventilation of the BEC system-induced by artificially openings-is not a direct analogue for pre-1860 ventilation conditions. The artificial change of ventilation resulted in a strong increase of ?13Cspeleothem values. Prior to the cave opening in 1860, Holocene ?13Cspeleothem values were significantly lower, probably related to limited ventilation due to the lack of significant connections between the surface and cave. Reduced ventilation led to significantly higher pCO2 values, minimal CO2 degassing from drip water and low kinetic isotope fractionation. Both modern and fossil speleothem precipitation rates are driven by water supply and carbonate saturation, and not by cave air pCO2. Today, pCO2 variability is too small to affect carbonate precipitation rates and the same is likely true for pCO2 variability prior to artificial opening of the cave. Thus, fossil speleothems from BEC System are likely more sensitive to temperature and infiltration dynamics. The Bunker-Emst Cave System, therefore, represents different ventilation patterns and their influence on speleothem proxy data in an exemplary manner, and it may serve as a template for other cave systems

Dropout: Students leaving urban high schools prior to graduation

Urban high schools in America are not generating the desired results; the low graduation rate in large cities must be addressed. Existing literature discussing the high school dropout issue is examined. Many factors contribute to school dropout, which has an impact on the individual and society. Several of the potential causes are examined and connections between multiple causes are noted. Quantitative and qualitative studies were used to create a complete view of this issue. Dropout prevention methods and programs are described, as is the role of school counselors in dropout prevention. A phenomenological study was also conducted to gain the personal perspective of individuals who dropped out of an urban school district. The specific goal of the research was to determine what factors contributed to students deciding to drop out of high school. Seven individuals participating in a General Education Diploma program shared their experience of dropping out of high school. Individual and small group interviews were conducted. The experiences reported were compared among each participant and were also related to the results of existing research. Results varied among participants, they reflected both the individual and the school community. Conclusions have been drawn and are reported as they relate to the role of a school counselor