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Search Results: 1 - 10 of 1365 matches for " Melanie Volkamer "
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Ein PKI-basiertes Protokoll für sichere und praktikable Onlinewahlen
Lucie Langer,Axel Schmidt,Melanie Volkamer,Johannes Buchmann
eJournal of eDemocracy & Open Government , 2010,
Abstract: Wir stellen ein Protokoll für Onlinewahlen vor, welches auf dem Schema von Ohkubo et al. [13] basiert. Besonders an diesem Protokoll ist, dass der Ausz hler nicht vertrauenswürdig sein muss. Der geheime Schlüssel des Ausz hlers wird am Ende der Wahl ver ffentlicht und erm glicht so die universelle Verifizierbarkeit der Stimmausz hlung. Wir diskutieren die Sicherheit des Protokolls angesichts der allgemein anerkannten Sicherheitsanforderungen für elektronische Wahlschemata.
Developing an educational framework for the teaching of simulation within nurse education  [PDF]
Melanie Humphreys
Open Journal of Nursing (OJN) , 2013, DOI: 10.4236/ojn.2013.34049
Abstract:

The use of simulations as a teaching and learning tool within health care has increasing importance; simulations are seen as the major teaching method for practicing and assessing developing skills, knowledge, attitudes and meaningful decision-making within the field of nursing. Certainly the utilisations of simulations feature widely within many aspects of health care; a greater understanding of the key conceptual notions will serve to benefit all of those engaged within their application. This literature review has enabled the construction of a conceptual model for the teaching of simulation and can serve to promote the continued positive development of simulations within education. Through a consistent and insightful approach to teaching, dynamic learning will be assured within this very important aspect of engaging the nursing student within the learning process.

Glyoxal processing by aerosol multiphase chemistry: towards a kinetic modeling framework of secondary organic aerosol formation in aqueous particles
B. Ervens,R. Volkamer
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2010,
Abstract: This study presents a modeling framework based on laboratory data to describe the kinetics of glyoxal reactions that form secondary organic aerosol (SOA) in aqueous aerosol particles. Recent laboratory results on glyoxal reactions are reviewed and a consistent set of empirical reaction rate constants is derived that captures the kinetics of glyoxal hydration and subsequent reversible and irreversible reactions in aqueous inorganic and water-soluble organic aerosol seeds. Products of these processes include (a) oligomers, (b) nitrogen-containing products, (c) photochemical oxidation products with high molecular weight. These additional aqueous phase processes enhance the SOA formation rate in particles and yield two to three orders of magnitude more SOA than predicted based on reaction schemes for dilute aqueous phase (cloud) chemistry for the same conditions (liquid water content, particle size). The application of the new module including detailed chemical processes in a box model demonstrates that both the time scale to reach aqueous phase equilibria and the choice of rate constants of irreversible reactions have a pronounced effect on the predicted atmospheric relevance of SOA formation from glyoxal. During day time, a photochemical (most likely radical-initiated) process is the major SOA formation pathway forming ~5 μg m 3 SOA over 12 h (assuming a constant glyoxal mixing ratio of 300 ppt). During night time, reactions of nitrogen-containing compounds (ammonium, amines, amino acids) contribute most to the predicted SOA mass; however, the absolute predicted SOA masses are reduced by an order of magnitude as compared to day time production. The contribution of the ammonium reaction significantly increases in moderately acidic or neutral particles (5 < pH < 7). Glyoxal uptake into ammonium sulfate seed under dark conditions can be represented with a single reaction parameter keffupt that does not depend on aerosol loading or water content, which indicates a possibly catalytic role of aerosol water in SOA formation. However, the reversible nature of uptake under dark conditions is not captured by keffupt, and can be parameterized by an effective Henry's law constant including an equilibrium constant Kolig = 1000 (in ammonium sulfate solution). Such reversible glyoxal oligomerization contributes <1% to total predicted SOA masses at any time. Sensitivity tests reveal five parameters that strongly affect the predicted SOA mass from glyoxal: (1) time scales to reach equilibrium states (as opposed to assuming instantaneous equilibrium), (2) particle pH, (3) chemical composition of the bulk aerosol, (4) particle surface composition, and (5) particle liquid water content that is mostly determined by the amount and hygroscopicity of aerosol mass and to a lesser extent by the ambient relative humidity. Glyoxal serves as an example molecule, and the conclusions about SOA formation in aqueous particles can serve for comparative studies of other molecules th
Inherent calibration of a blue LED-CE-DOAS instrument to measure iodine oxide, glyoxal, methyl glyoxal, nitrogen dioxide, water vapour and aerosol extinction in open cavity mode
R. Thalman,R. Volkamer
Atmospheric Measurement Techniques (AMT) & Discussions (AMTD) , 2010,
Abstract: The combination of Cavity Enhanced Absorption Spectroscopy (CEAS) with broad-band light sources (e.g. Light-Emitting Diodes, LEDs) lends itself to the application of cavity enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) to perform sensitive and selective point measurements of multiple trace gases and aerosol extinction with a single instrument. In contrast to other broad-band CEAS techniques, CE-DOAS relies only on the measurement of relative intensity changes, i.e. does not require knowledge of the light intensity in the absence of trace gases and aerosols (I0). We have built a prototype LED-CE-DOAS instrument in the blue spectral range (420–490 nm) to measure nitrogen dioxide (NO2), glyoxal (CHOCHO), methyl glyoxal (CH3COCHO), iodine oxide (IO), water vapour (H2O) and oxygen dimers (O4). We demonstrate the first direct detection of methyl glyoxal, and the first CE-DOAS detection of CHOCHO and IO. The instrument is further inherently calibrated for light extinction from the cavity by observing O4 or H2O (at 477 nm and 443 nm) and measuring the pressure, relative humidity and temperature independently. This approach is demonstrated by experiments where laboratory aerosols of known size and refractive index were generated and their extinction measured. The measured extinctions were then compared to the theoretical extinctions calculated using Mie theory (3–7 × 10 7cm 1). Excellent agreement is found from both the O4 and H2O retrievals. This enables the first inherently calibrated CEAS measurement at blue wavelengths in open cavity mode, and eliminates the need for sampling lines to supply air to the cavity, i.e., keep the cavity enclosed and/or aerosol free. Measurements in open cavity mode are demonstrated for CHOCHO, CH3COCHO, NO2, H2O and aerosol extinction. Our prototype LED-CE-DOAS provides a low cost, yet research grade innovative instrument for applications in simulation chambers and in the open atmosphere.
Inherent calibration of a novel LED-CE-DOAS instrument to measure iodine oxide, glyoxal, methyl glyoxal, nitrogen dioxide, water vapour and aerosol extinction in open cavity mode
R. Thalman,R. Volkamer
Atmospheric Measurement Techniques Discussions , 2010, DOI: 10.5194/amtd-3-2681-2010
Abstract: The combination of Cavity Enhanced Absorption Spectroscopy (CEAS) with broad-band light sources (e.g. Light-Emitting Diodes, LEDs) lends itself to the application of cavity enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) to perform sensitive and selective point measurements of multiple trace gases and aerosol extinction with a single instrument. In contrast to other broad-band CEAS techniques, CE-DOAS relies only on the measurement of relative intensity changes, i.e. does not require knowledge of the light intensity in the absence of trace gases and aerosols (I0). We have built a prototype LED-CE-DOAS instrument in the blue spectral range (420–490 nm) to measure nitrogen dioxide (NO2), glyoxal (CHOCHO), methyl glyoxal (CH3COCHO), iodine oxide (IO), water vapour (H2O) and oxygen dimers (O4). We demonstrate the first CEAS detection of methyl glyoxal, and the first CE-DOAS detection of CHOCHO and IO. A further innovation consists in the measurement of extinction losses from the cavity, e.g. due to aerosols, at two wavelengths by observing O4 (477 nm) and H2O (443 nm) and measuring the pressure, relative humidity and temperature independently. This approach is demonstrated by experiments where laboratory aerosols of known size and refractive index were generated and their extinction measured. The measured extinctions were then compared to the theoretical extinctions calculated using Mie theory (3–7×10-7 cm-1). Excellent agreement is found from both the O4 and H2O retrievals. This enables the first inherently calibrated CEAS measurement in open cavity mode (mirrors facing the open atmosphere), and eliminates the need for sampling lines to supply air to the cavity, and/or keep the cavity enclosed and aerosol free. Measurements in open cavity mode are demonstrated for CHOCHO, CH3COCHO, NO2, H2O and aerosol extinction at 477 nm and 443 nm. Our prototype LED-CE-DOAS provides a low cost, yet research grade innovative instrument for applications in simulation chambers and in the open atmosphere.
Approaching the Direct Object Pronouns: How Much Grammatical Form Is Necessary in Instruction?  [PDF]
Melanie L. D’Amico
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.34041
Abstract: The main goal of this investigation was to determine if there is a more effective approach among focus on forms, focus on meaning, or focus on form for teaching the direct object pronouns to beginning students of Spanish. It will be beneficial to discover which of these three widely-used approaches can best help students to acquire correct pronoun use, and may aid instructors of Spanish in the teaching of these pronouns. In order to compare these approaches, three sections of a beginning Spanish course received instruction in one of the three approaches. The participants of this study were 51 beginning level students who had had 3 years of Spanish instruction at the high school level and were native speakers of English. The study follows a pretest/posttest design. Results find positive results for form-focused instruction over purely meaning-focused instruction for teaching the Spanish direct object pronouns with regards to sentence completion tasks. A main implication of this study is that focus on meaning instruction is not sufficient to help beginning learners improve their production of Spanish direct object pronouns. While results show a more positive impact for focus on form instruction over the more traditional focus on forms approach, additional research comparing these two methods is suggested. It is also important to note that beginning level learners show overall low levels of accuracy with direct object pronouns in Spanish.
Complexity of Interaction in a Second Language Conversation Group: An Exploratory Study  [PDF]
Melanie Lynn D’Amico
Open Journal of Modern Linguistics (OJML) , 2015, DOI: 10.4236/ojml.2015.54031
Abstract: The aim of this research was to explore the nature of conversation in a weekly second language Italian conversation group. Analysis of conversations focused on the range of topics and verbal structures used by learners. Additional analysis was completed to determine if learners engaged in negotiation of meaning or form during conversations. Results revealed that learners used a range of topics and verbal structures from Beginner level to Advanced level indicating that learners challenged themselves to produce high quality, natural conversation. Learners also showed some use of negotiation during conversations to repair communication breakdowns, principally to address meaning; however, the amount of negotiation was low when compared to task-based interaction designed to elicit negotiation.
Tackling Tuberculosis in Latvia
Melanie Zipperer
PLOS Medicine , 2005, DOI: 10.1371/journal.pmed.0020122
Abstract:
Emerging Patient-Driven Health Care Models: An Examination of Health Social Networks, Consumer Personalized Medicine and Quantified Self-Tracking
Melanie Swan
International Journal of Environmental Research and Public Health , 2009, DOI: 10.3390/ijerph6020492
Abstract: A new class of patient-driven health care services is emerging to supplement and extend traditional health care delivery models and empower patient self-care. Patient-driven health care can be characterized as having an increased level of information flow, transparency, customization, collaboration and patient choice and responsibility-taking, as well as quantitative, predictive and preventive aspects. The potential exists to both improve traditional health care systems and expand the concept of health care though new services. This paper examines three categories of novel health services: health social networks, consumer personalized medicine and quantified self-tracking.
Sensor Mania! The Internet of Things, Wearable Computing, Objective Metrics, and the Quantified Self 2.0
Melanie Swan
Journal of Sensor and Actuator Networks , 2012, DOI: 10.3390/jsan1030217
Abstract: The number of devices on the Internet exceeded the number of people on the Internet in 2008, and is estimated to reach 50 billion in 2020. A wide-ranging Internet of Things (IOT) ecosystem is emerging to support the process of connecting real-world objects like buildings, roads, household appliances, and human bodies to the Internet via sensors and microprocessor chips that record and transmit data such as sound waves, temperature, movement, and other variables. The explosion in Internet-connected sensors means that new classes of technical capability and application are being created. More granular 24/7 quantified monitoring is leading to a deeper understanding of the internal and external worlds encountered by humans. New data literacy behaviors such as correlation assessment, anomaly detection, and high-frequency data processing are developing as humans adapt to the different kinds of data flows enabled by the IOT. The IOT ecosystem has four critical functional steps: data creation, information generation, meaning-making, and action-taking. This paper provides a comprehensive review of the current and rapidly emerging ecosystem of the Internet of Things (IOT).
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