Water in a Changing World

Life on earth depends on the continuous flow of materials through the air, water, soil, and food webs of the biosphere. The movement of water through the hydrological cycle comprises the largest of these flows, delivering an estimated I 10,000 cubic kilometers (km^\u3e of water to the land each year as snow and rainfall. Solar energy drives the hydrological cycle, vaporizing water from the surface of oceans, lakes, and rivers as well as from soils and plants (evapotranspiration). Water vapor rises into the atmosphere where it cools, condenses, and eventually rains down anew. This renewable freshwater supply sustains life on the land, in estuaries, and in the freshwater ecosystems of the earth

Efficient at-most-once messages based on synchronized clocks

This paper describes a new message passing protocol that provides guaranteed detection of duplicate messages even when the receiver has no state stored for the sender

The chemistry of episodic accretion in embedded objects : 2D radiation thermo-chemical models of the post-burst phase

RCH and EV acknowledge funding by the Austrian Science Fund (FWF): project number I2549-N27. RCH and MG acknowledge funding by the Austrian Science Fund (FWF): project number P24790.MAand AP acknowledge funding by the Swiss National Science Foundation (SNSF): project number: 200021L_163172. The research leading to these results has received funding from the European Union Seventh Framework Programme FP7-2011 under grant agreement no 284405. This publication was partly supported from the FFG ASAP 12 project JetPro* (FFG-854025). This publication was supported by the Austrian Science Fund (FWF). The computational results presented have been achieved using the Vienna Scientific Cluster (VSC).Context. Episodic accretion is an important process in the evolution of young stars and their environment. The observed strong luminosity bursts of young stellar objects likely have a long lasting (i.e. longer than the burst duration) impact on the chemical evolution of the disk and envelope of young stars. Aims. We aim to investigate the observational signatures of the chemical evolution in the post-burst phase for embedded sources. With such signatures it is possible to identify targets that experienced a recent luminosity burst. Methods. We present a new model for the chemistry of episodic accretion based on the two dimensional, radiation thermo-chemical disk code PRODIMO (PROtoplanetary DIsk MOdel). We have extended PRODIMO with a proper treatment for envelope structures. For a representative Class I model, we calculated the chemical abundances in the post-burst phase and produced synthetic observables such as intensity maps and radial intensity profiles. Results. During a burst, many chemical species, such as CO, sublimate from the dust surfaces. As the burst ends they freeze out again (post-burst phase). This freeze-out happens from inside-out due to the radial density gradient in the disk and envelope structure. This inside-out freeze-out produces clear observational signatures in spectral line emission, such as rings and distinct features in the slope of radial intensity profiles. We fitted synthetic C18O J = 2−1 observations with single and two component fits and find that post-burst images are much better matched by the latter. Comparing the quality of such fits therefore allows identification of post-burst targets in a model-independent way. Conclusions. Our models confirm that it is possible to identify post-burst objects from spatially resolved CO observations. However, to derive proper statistics, such as the strength and frequencies of bursts, from observations it is important to consider the inclination and structure of the target and dust properties, as these have a significant impact on the freeze-out timescale.PostprintPeer reviewe

Assessment of function and clinical utility of alcohol and other drug web sites: An observational, qualitative study

Background The increasing popularity and use of the internet makes it an attractive option for providing health information and treatment, including alcohol/other drug use. There is limited research examining how people identify and access information about alcohol or other drug (AOD) use online, or how they assess the usefulness of the information presented. This study examined the strategies that individuals used to identify and navigate a range of AOD websites, along with the attitudes concerning presentation and content. Methods Members of the general community in Brisbane and Roma (Queensland, Australia) were invited to participate in a 30-minute search of the internet for sites related to AOD use, followed by a focus group discussion. Fifty one subjects participated in the study across nine focus groups. Results Participants spent a maximum of 6.5 minutes on any one website, and less if the user was under 25 years of age. Time spent was as little as 2 minutes if the website was not the first accessed. Participants recommended that AOD-related websites should have an engaging home or index page, which quickly and accurately portrayed the site’s objectives, and provided clear site navigation options. Website content should clearly match the title and description of the site that is used by internet search engines. Participants supported the development of a portal for AOD websites, suggesting that it would greatly facilitate access and navigation. Treatment programs delivered online were initially viewed with caution. This appeared to be due to limited understanding of what constituted online treatment, including its potential efficacy. Conclusions A range of recommendations arise from this study regarding the design and development of websites, particularly those related to AOD use. These include prudent use of text and information on any one webpage, the use of graphics and colours, and clear, uncluttered navigation options. Implications for future website development are discussed

Veröffentlichungen aus dem Staatsarchiv der Freien und Hansestadt Hamburg

Das Staatsarchiv Hamburg feierte 2010 sein 300-jähriges Bestehen. Sein Vorläufer wurde bereits im Jahre 1293 erstmals erwähnt und somit die Aufbewahrung wichtiger Dokumente der Stadt an zentraler Stelle bezeugt. Doch erst seit dem 11. September 1710, dem Amtsantritt von Nicolaus Stampeel als wissenschaftlicher Archivar bei der Stadt Hamburg, werden Dokumente systematisch ausgewählt, bewahrt und erschlossen. Dieses Jubiläum hat das Staatsarchiv mit einem breit gefächerten Veranstaltungsprogramm begangen, zu dem auch Vorträge und Lesungen gehörten, die in der hier vorliegenden Festschrift abgedruckt sind.In 2010, the Hamburg State Archives celebrated its 300th anniversary. The Archives\u27 forerunner was first mentioned in 1293 and thus testified to the preservation of important documents of the city in a central place. But it was not until September 11th, 1710, when Nicolaus Stampeel took office as a scientific archivist at the City of Hamburg. From then on, documents were systematically selected, preserved and indexed. This anniversary was celebrated by the State Archives with a broad programme of events, which included lectures and readings printed in the commemorative volume available here