Exact Strongly Coupled Fixed Point in gφ4g\varphi^4 Theory

We show explicitly how a strongly coupled fixed point can be constructed in scalar $g\varphi^4$ theory from the solutions to a non-linear eigenvalue problem. The fixed point exists only for $d< 4$, is unstable and characterized by $\nu=2/d$ (correlation length exponent), $\eta=1/2-d/8$ (anomalous dimension). For $d=2$, these exponents reproduce to those of the Ising model which can be understood from the codimension of the critical point. At this fixed point, $\varphi^{2i}$ terms with $i>2$ are all irrelevant. The testable prediction of this fixed point is that the specific heat exponent vanishes. 2d critical Mott systems are well described by this new fixed point.Comment: revised version of previous paper with a proof of the irrelevance of \varphi^6 and higher terms at fixed poin

Physical controls on orographic cirrus inhomogeneity

Optical depth distributions (P(σ)) are a useful measure of radiatively important cirrus (Ci) inhomogeneity. Yet, the relationship between P(σ) and underlying cloud physical processes remains unclear. In this study, we investigate the influence of homogeneous and heterogeneous freezing processes, ice particle growth and fallout, and mesoscale vertical velocity fluctuations on P(σ) shape during an orographic Ci event. We evaluate Lagrangian Ci evolution along kinematic trajectories from a mesoscale weather model (MM5) using an adiabatic parcel model with binned ice microphysics. Although the presence of ice nuclei increased model cloud cover, our results highlight the importance of homogeneous freezing and mesoscale vertical velocity variability in controlling Ci P(σ) shape along realistic upper tropospheric trajectories

One century of hydrological monitoring in two small catchments with different forest coverage

Long-term data on precipitation and runoff are essential to draw firm conclusions about the behavior and trends of hydrological catchments that may be influenced by land use and climate change. Here the longest continuous runoff records from small catchments (<1km2) in Switzerland (and possibly worldwide) are reported. The history of the hydrological monitoring in the Sperbel- and Rappengraben (Emmental) is summarized, and inherent uncertainties in the data arising from the operation of the gauges are described. The runoff stations operated safely for more than 90% of the summer months when most of the major flood events occurred. Nevertheless, the absolute values of peak runoff during the largest flood events are subject to considerable uncertainty. The observed differences in average, base, and peak runoff can only partly be attributed to the substantial differences in forest coverage. This treasure trove of data can be used in various ways, exemplified here with an analysis of the generalized extreme value distributions of the two catchments. These distributions, and hence flood return periods, have varied greatly in the course of one century, influenced by the occurrence of single extreme events. The data will be made publicly available for the further analysis of the mechanisms governing the runoff behavior of small catchments, as well as for testing stochastic and deterministic model

Uncertainty propagation for flood forecasting in the Alps: different views and impacts from MAP D-PHASE

D-PHASE was a Forecast Demonstration Project of theWorldWeather Research Programme (WWRP) related to the Mesoscale Alpine Programme (MAP). Its goal was to demonstrate the reliability and quality of operational forecasting of orographically influenced (determined) precipitation in the Alps and its consequences on the distribution of run-off characteristics. A special focus was, of course, on heavy-precipitation events. The D-PHASE Operations Period (DOP) ran from June to November 2007, during which an end-to-end forecasting system was operated covering many individual catchments in the Alps, with their water authorities, civil protection organizations or other end users. The forecasting system’s core piece was a Visualization Platform where precipitation and flood warnings from some 30 atmospheric and 7 hydrological models (both deterministic and probabilistic) and corresponding model fields were displayed in uniform and comparable formats. Also, meteograms, nowcasting information and end user communication was made available to all the forecasters, users and end users. D-PHASE information was assessed and used by some 50 different groups ranging from atmospheric forecasters to civil protection authorities or water management bodies. In the present contribution, D-PHASE is briefly presented along with its outstanding scientific results and, in particular, the lessons learnt with respect to uncertainty propagation. A focus is thereby on the transfer of ensemble prediction information into the hydrological community and its use with respect to other aspects of societal impact. Objective verification of forecast quality is contrasted to subjective quality assessments during the project (end user workshops, questionnaires) and some general conclusions concerning forecast demonstration projects are drawn

Sources of light-absorbing aerosol in arctic snow and their seasonal variation

Two data sets consisting of measurements of light absorbing aerosols (LAA) in arctic snow together with suites of other corresponding chemical constituents are presented; the first from Siberia, Greenland and near the North Pole obtained in 2008, and the second from the Canadian arctic obtained in 2009. A preliminary differentiation of the LAA into black carbon (BC) and non-BC LAA is done. Source attribution of the light absorbing aerosols was done using a positive matrix factorization (PMF) model. Four sources were found for each data set (crop and grass burning, boreal biomass burning, pollution and marine). For both data sets, the crops and grass biomass burning was the main source of both LAA species, suggesting the non-BC LAA was brown carbon. Depth profiles at most of the sites allowed assessment of the seasonal variation in the source strengths. The biomass burning sources dominated in the spring but pollution played a more significant (though rarely dominant) role in the fall, winter and, for Greenland, summer. The PMF analysis is consistent with trajectory analysis and satellite fire maps

An instrument for measuring size-resolved aerosol hygroscopicity at both sub- and super-micron sizes

The article of record as published may be found at http://dx.doi.org/10.1080/02786820701506955A new instrument to measure the size-resolved hygroscopic growth of both sub- and super-micron atmospheric aerosol is described. It consists of two white-light optical particle counters measuring the same sample aerosol simultaneously at two different controlled relative humidities. Calibration with aerosols of different refractive index confirms the expected relative insensitivity of the instrument to index of refraction. Data obtained in the field from airborne sampling support the utility of the instrument in measuring differences in size-resolved hygroscopicity in the marine boundary layer and also in addressing the issue of kinetic limitations to aerosol condensational growth.Office of Naval ResearchGrant no. N0014-97-1-013

Influence of storm damage on the runoff generation in two sub-catchments of the Sperbelgraben, Swiss Emmental

The project "Lothar and Mountain Torrents” investigates the effect of storm-originated deforestation on the hydrology on three scales within the Sperbelgraben catchment (Swiss Prealps). This article focuses on runoff measurements during a 3-year period in two differently affected sub-catchments (≈2ha) and on 2-year surface runoff measurements on smaller plots (50-110m2). The link between these two scales and the results of irrigation experiments on 1m2 areas are interpreted using a detailed map of forest site types describing soil and vegetation characteristics. Plot results show that surface runoff is generated in two distinct ways. On the one hand, high amounts of saturation overland flow were observed on wet areas of gleyic soils. On the other hand, hardly any surface runoff was measured on Cambisols, with the exception of a short hydrophobic reaction at the beginning of storms occurring on areas with a thick organic litter layer (temporary Hortonian overland flow). On the long term, the lightly damaged sub-catchment (SC1) yields less runoff than the highly damaged one (SC2). This is confirmed when direct runoff volumes during flood events are considered. However, short and intensive showers surprisingly lead to higher discharge peaks in SC1. This occurrence is explained by different geomorphologic characteristics (mainly the channel density) and the spatial distribution of the moist to wet forest site types. Effects of deforestation and local soil compaction due to forest clearing remain small on both plot and sub-catchment scal

Student nurses' experiences of infection prevention and control during clinical placements

Background: Little is known about nursing students' experiences of infection control in the clinical setting despite its importance protecting patients and reducing risks of occupational exposure. Methods: We conducted an online survey involving a fixed choice Likert-type scale with 19 items and an open question to solicit more detailed information with a national sample of student nurses in the United Kingdom. Results: Four hundred eighty-eight student nurses completed questionnaires. All participants reported lack of compliance for every item on the Likert scale, most frequently from community settings and long-term care facilities for older people. Incidents most commonly witnessed were failure to comply with hand hygiene protocols, failure to comply with isolation precautions, poor standards of cleaning in the patient environment, not changing personal protective clothing between patients, and poor management of sharp instruments. Qualified nurses did not provide good role models. Medical staff were the occupational group most heavily criticized for poor compliance. Conclusion: Students demonstrated sound understanding of infection control and were able to identify lack of compliance on the basis of preclinical classroom instruction. The study findings indicate that ensuring safe infection control practice remains a challenge in the United Kingdom despite its high priority

Resource efficiency and life cycle environmental impacts of biogas production at Greve Biogass - Ressurseffektivitet og livsløps miljøpåvirkning av biogassproduksjon ved Greve Biogass

In Norway, the municipalities are obligated to contribute to the reduction of greenhouse gas emissions as well as to a transition towards green energy. Biogas production based on manure, sewage sludge and different types of waste holds a large potential for decreasing emissions of climate gases. Greve Biogass AS, on behalf of its owner municipalities in Vestfold and Telemark will build a biogas plant, The Magic Factory , with the purpose of ensuring local recycling. The biogas plant will utilize large amounts of manure as substitution for clean drinking water as process water. The objective of this Thesis is to study the specific choices made regarding the operation of The Magic Factory , considering potential outputs, resource efficiency and environmental impacts. Three main choices have been studied: benefits of establishing The Magic Factory benefits of the water choices benefits of The Magic Factory compared to other biogas plants that do not treat such large amount of manure This has been carried out by use of material flow analysis and life cycle assessment, investigating six different scenarios, each of them representing different substrate mixtures and handlings. The environmental impacts have been concentrated on four impact categories: climate change human toxicity water depletion fossil depletion The results from the material flow analysis show that the outputs and resource efficiency are dependent on substrate mixture and transportation distance. When a co-digestion benefit has not been accounted for, a higher output of biofuel is seen by processing solid manure over liquid manure, and food waste over manure. This Thesis supports the choices made by Greve Biogass AS for the operation of The Magic Factory , considering environmental benefits. The results show that there is an environmental benefit of establishing The Magic Factory , considering all four impact categories. Environmentally, it is slightly beneficial to substitute clean water with liquid manure and The Magic Factory asserts itself good environmentally when compared to other plants by including manure in the biogas production. The sensitivity analysis performed shows that out of the uncertain parameters, degradability is the one with the highest impact on the outputs, resource efficiency as well as on the environment. This means that the parameter should be evaluated and adjusted after the results of a case specific digestion test are known. The driving distance related to collection and transportation of the food waste does have an influence that should be taken into account when considering what waste fractions to be processed at the plant