A Classical Density-Functional Theory for Describing Water Interfaces

We develop a classical density functional for water which combines the White Bear fundamental-measure theory (FMT) functional for the hard sphere fluid with attractive interactions based on the Statistical Associating Fluid Theory (SAFT-VR). This functional reproduces the properties of water at both long and short length scales over a wide range of temperatures, and is computationally efficient, comparable to the cost of FMT itself. We demonstrate our functional by applying it to systems composed of two hard rods, four hard rods arranged in a square and hard spheres in water

Ship emissions of SO2 and NO2: DOAS measurements from airborne platforms

A unique methodology to measure gas fluxes of SO2 and NO2 from ships using optical remote sensing is described and demonstrated in a feasibility study. The measurement system is based on Differential Optical Absorption Spectroscopy using reflected skylight from the water surface as light source. A grating spectrometer records spectra around 311 nm and 440 nm, respectively, with the telescope pointed downward at a 30A degrees angle from the horizon. The mass column values of SO2 and NO2 are retrieved from each spectrum and integrated across the plume. A simple geometric approximation is used to calculate the optical path. To obtain the total emission in kg h(-1) the resulting total mass across the plume is multiplied with the apparent wind, i.e. a dilution factor corresponding to the vector between the wind and the ship speed. The system was tested in two feasibility studies in the Baltic Sea and Kattegat, from a CASA-212 airplane in 2008 and in the North Sea outside Rotterdam from a Dauphin helicopter in an EU campaign in 2009. In the Baltic Sea the average SO2 emission out of 22 ships was (54 +/- 13) kg h(-1), and the average NO2 emission was (33 +/- 8) kg h(-1), out of 13 ships. In the North Sea the average SO2 emission out of 21 ships was (42 +/- 11) kg h(-1), NO2 was not measured here. The detection limit of the system made it possible to detect SO2 in the ship plumes in 60% of the measurements when the described method was used. A comparison exercise was carried out by conducting airborne optical measurements on a passenger ferry in parallel with onboard measurements. The comparison shows agreement of (-30 +/- 14)% and (-41 +/- 11)%, respectively, for two days, with equal measurement precision of about 20%. This gives an idea of the measurement uncertainty caused by errors in the simple geometric approximation for the optical light path neglecting scattering of the light in ocean waves and direct and multiple scattering in the exhaust plume under various conditions. A tentative error budget indicates uncertainties within 30-45% but for a reliable error analysis the optical light path needs to be modelled. A ship emission model, FMI-STEAM, has been compared to the optical measurements showing an 18% overestimation and a correlation coefficient (R-2) of 0.6. It is shown that a combination of the optical method with modelled power consumption can estimate the sulphur fuel content within 40%, which would be sufficient to detect the difference between ships running at 1% and at 0.1%, limits applicable within the IMO regulated areas

Efficacy of adalimumab as second-line therapy in a pediatric cohort of crohn’s disease patients who failed infliximab therapy: The Italian society of pediatric gastroenterology, hepatology, and nutrition experience

Background: Adalimumab (Ada) treatment is an available option for pediatric Crohn’s disease (CD) and the published experience as rescue therapy is limited. Objectives: We investigated Ada efficacy in a retrospective, pediatric CD cohort who had failed previous infliximab treatment, with a minimum follow-up of 6 months. Methods: In this multicenter study, data on demographics, clinical activity, growth, laboratory values (CRP) and adverse events were collected from CD patients during follow-up. Clinical remission (CR) and response were defined with Pediatric CD Activity Index (PCDAI) score ≤10 and a decrease in PCDAI score of ≥12.5 from baseline, respectively. Results: A total of 44 patients were consecutively recruited (mean age 14.8 years): 34 of 44 (77%) had active disease (mean PCDAI score 24.5) at the time of Ada administration, with a mean disease duration of 3.4 (range 0.3–11.2) years. At 6, 12, and 18 months, out of the total of the enrolled population, CR rates were 55%, 78%, and 52%, respectively, with a significant decrease in PCDAI scores (P<0.01) and mean CRP values (mean CRP 5.7 and 2.4 mL/dL, respectively; P<0.01) at the end of follow-up. Steroid-free remission rates, considered as the total number of patients in CR who were not using steroids at the end of this study, were 93%, 95%, and 96% in 44 patients at 6, 12, and 18 months, respectively. No significant differences in growth parameters were detected. In univariate analysis of variables related to Ada efficacy, we found that only a disease duration >2 years was negatively correlated with final PCDAI score (P<0.01). Two serious adverse events were recorded: 1 meningitis and 1 medulloblastoma. Conclusion: Our data confirm Ada efficacy in pediatric patients as second-line biological therapy after infliximab failure. Longer-term prospective data are warranted to define general effectiveness and safety in pediatric CD patients

Peroxy radicals in the summer free troposphere: seasonality and potential for heterogeneous loss

The sum of peroxy radicals (HO2+ΣiRiO2) and supporting trace gases were measured on the Jungfraujoch (3580 m a.s.l.) during the late summer of 2005. The period was marked by extended times of heavy snow which led to reduction in the observed peroxy radicals during the snowy periods that was greater than the concomitant reduction in j(O1D). In the limit a first order loss rate of 0.0063 s−1 can be derived for the peroxy radical loss in the snowy conditions that could be potentially ascribed to a heterogenous loss process. On snow free days photolysis of HCHO is shown to be a significant peroxy radical source. The seasonal trends of the peroxy radical concentrations have been mapped from the winter to summer transition in line with previous experiments. Net ozone production in late summer at the Jungfraujoch was net neutral to marginally ozone destructive. A value of 28±4 pptv is calculated for the ozone compensation point for the snow free days.ISSN:1680-7375ISSN:1680-736

Minimal Work Principle and its Limits for Classical Systems

The minimal work principle asserts that work done on a thermally isolated equilibrium system, is minimal for the slowest (adiabatic) realization of a given process. This principle, one of the formulations of the second law, is operationally well-defined for any finite (few particle) Hamiltonian system. Within classical Hamiltonian mechanics, we show that the principle is valid for a system of which the observable of work is an ergodic function. For non-ergodic systems the principle may or may not hold, depending on additional conditions. Examples displaying the limits of the principle are presented and their direct experimental realizations are discussed.Comment: 4 + epsilon pages, 1 figure, revte

The CASPER project: an integrated approach for pollution risk assessment in peri-urban groundwater catchment areas

In 2020, the European Union has established a recast of the 1998 EU Directive on the quality of water intended for human consumption, hereafter called Drinking Water Directive – DWD. One of the most significant innovative point in this recast is the introduction of an innovative “complete risk-based approach to water safety, covering the whole supply chain from the catchment area, abstraction, treatment, storage and distribution to the point of compliance” (article 7). In practice, a 3-level risk assessment and risk management is expected: (1) at the level of the catchment area (article 8), (2) at the level of the water supply systems (article 9) and (3) at the level of the domestic distribution system (article 10). In this context, the CASPER project, funded by SPGE in the Walloon Region of Belgium, aims at developing an integrated approach for the evaluation and management of pollution risks for peri-urban groundwater catchments. The approach, which fully complies with the requirements of the DWD recast, consists of several key components. First, point and diffuse pollution sources are identified in the groundwater catchment area based on a mapping of hazardous activities combined with a specific groundwater monitoring survey aiming at identifying specific tracers of such sources of pollution. In a second step, risks associated to each of the identified source of pollution is estimated based on the measurement of pollutant mass fluxes and mass discharges downgradient these sources. Finally, a groundwater flow and transport model is developed at the scale of the groundwater catchment area, with the aim of evaluating the cumulative effect of the multiple sources on groundwater quality deterioration in the catchment and at the abstraction points. The objective here is to describe the CASPER approach and to illustrate it using ongoing investigations in a peri-urban groundwater catchment exploiting groundwater from a chalk aquifer in Western Belgium.</p

Using stable isotopes to analyse extinction risks and reintroduction opportunities of native species in invaded ecosystems.

Invasive non-native species have pervasive impacts on native biodiversity, including population extirpations and species extinctions. Identifying reasons why a population of a native species is extirpated following an invasion often relies on literature-based results of anecdotal observations. The well-established schemes of existing risk assessments for invasive species assume that a species' information (e.g. impacts or behavioural and biological traits) can be projected from one area to another to estimate the potential impact of a species in another environment. We used stable isotope data (δ13C, δ15N) from both invaded and uninvaded communities to predict such invasion impacts by reconstructing trophic relationships. This approach was tested on a community within a protected lake in Northern Spain where, following the introductions of non-native species, the last resident native species (the common tench Tinca tinca, the European eel Anguilla anguilla, and the whirligig beetle Gyrinus sp.) had been extirpated. Through the application of this novel approach, we found evidence that native species' declines were related to direct predation by and resource overlap with non-native species, which occurred in conjunction with habitat modification. Using this approach, we outlined the mechanisms involved in the extirpation of native species in the post-invasion period. To compensate for losses of native species induced by invasions of non-native species, native species reintroductions might be an appropriate tool. For this, we further suggested and discussed a novel approach that predicts the outcome of arising interactions by superimposing stable isotope data from alternative sources to better estimate the success of native species´ reintroductions

Atomic scale engines: Cars and wheels

We introduce a new approach to build microscopic engines on the atomic scale that move translationally or rotationally and can perform useful functions such as pulling of a cargo. Characteristic of these engines is the possibility to determine dynamically the directionality of the motion. The approach is based on the transformation of the fed energy to directed motion through a dynamical competition between the intrinsic lengths of the moving object and the supporting carrier.Comment: 4 pages, 3 figures (2 in color), Phys. Rev. Lett. (in print

Peroxy radicals in the summer free troposphere: seasonality and potential for heterogeneous loss

The sum of peroxy radicals (HO&lt;sub&gt;2&lt;/sub&gt;+&amp;Sigma;&lt;sub&gt;&lt;i&gt;i&lt;/i&gt;&lt;/sub&gt;R&lt;sub&gt;&lt;i&gt;i&lt;/i&gt;&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;) and supporting trace gases were measured on the Jungfraujoch (3580 m a.s.l.) during the late summer of 2005. The period was marked by extended times of heavy snow which led to reduction in the observed peroxy radicals during the snowy periods that was greater than the concomitant reduction in &lt;i&gt;j&lt;/i&gt;(O&lt;sup&gt;1&lt;/sup&gt;D). In the limit a first order loss rate of 0.0063 s&lt;sup&gt;&amp;minus;1&lt;/sup&gt; can be derived for the peroxy radical loss in the snowy conditions that could be potentially ascribed to a heterogenous loss process. On snow free days photolysis of HCHO is shown to be a significant peroxy radical source. The seasonal trends of the peroxy radical concentrations have been mapped from the winter to summer transition in line with previous experiments. Net ozone production in late summer at the Jungfraujoch was net neutral to marginally ozone destructive. A value of 28&amp;plusmn;4 pptv is calculated for the ozone compensation point for the snow free days