Analytical pair correlations in ideal quantum gases: Temperature-dependent bunching and antibunching

The fluctuation-dissipation theorem together with the exact density response spectrum for ideal quantum gases has been utilized to yield a new expression for the static structure factor, which we use to derive exact analytical expressions for the temperature{dependent pair distribution function g(r) of the ideal gases. The plots of bosonic and fermionic g(r) display "Bose pile" and "Fermi hole" typically akin to bunching and antibunching as observed experimentally for ultracold atomic gases. The behavior of spin-scaled pair correlation for fermions is almost featureless but bosons show a rich structure including long-range correlations near T_c. The coherent state at T=0 shows no correlation at all, just like single-mode lasers. The depicted decreasing trend in correlation with decrease in temperature for T < T_c should be observable in accurate experiments.Comment: 8 pages, 1 figure, minor revisio

Keyframe-based visual–inertial odometry using nonlinear optimization

Combining visual and inertial measurements has become popular in mobile robotics, since the two sensing modalities offer complementary characteristics that make them the ideal choice for accurate visual–inertial odometry or simultaneous localization and mapping (SLAM). While historically the problem has been addressed with filtering, advancements in visual estimation suggest that nonlinear optimization offers superior accuracy, while still tractable in complexity thanks to the sparsity of the underlying problem. Taking inspiration from these findings, we formulate a rigorously probabilistic cost function that combines reprojection errors of landmarks and inertial terms. The problem is kept tractable and thus ensuring real-time operation by limiting the optimization to a bounded window of keyframes through marginalization. Keyframes may be spaced in time by arbitrary intervals, while still related by linearized inertial terms. We present evaluation results on complementary datasets recorded with our custom-built stereo visual–inertial hardware that accurately synchronizes accelerometer and gyroscope measurements with imagery. A comparison of both a stereo and monocular version of our algorithm with and without online extrinsics estimation is shown with respect to ground truth. Furthermore, we compare the performance to an implementation of a state-of-the-art stochastic cloning sliding-window filter. This competitive reference implementation performs tightly coupled filtering-based visual–inertial odometry. While our approach declaredly demands more computation, we show its superior performance in terms of accuracy

Lexical neighborhood effects in pseudoword spelling

The general aim of this study is to contribute to a better understanding of the cognitive processes that underpin skilled adult spelling. More specifically, it investigates the influence of lexical neighbors on pseudo-word spelling with the goal of providing a more detailed account of the interaction between lexical and sublexical sources of knowledge in spelling. In prior research examining this topic, adult participants typically heard lists composed of both words and pseudo-words and had to make a lexical decision to each stimulus before writing the pseudo-words. However, these priming paradigms are susceptible to strategic influence and may therefore not give a clear picture of the processes normally engaged in spelling unfamiliar words. In our two Experiments involving 71 French-speaking literate adults, only pseudo-words we represented which participants were simply requested to write to dictation using the first spelling that came to mind. Unbeknownst to participants, pseudo-words varied according to whether they did or did not have a phonological word neighbor. Results revealed that low-probability yphoneme/grapheme mapping(e.g.,/o/-> aud in French)were used significantly more often in spelling pseudo-words with a close phonological lexical neighbour with that spelling(e.g.,/krepo/derived from “crapaud,”/krapo/)than in spelling pseudo-words with no close neighbors(e.g.,/frøpo/).In addition, the strength of this lexical influence increased with the lexical frequency of the word neighbors as well as with their degree of phonetic overlap with the pseudoword targets. These results indicate that information from lexical and sublexical processes is integrated in the course of spelling, and a specific theoretical account as to how such integration may occur is introduced

Prélèvement et échantillonnage dans les petits bassins-versants ruraux

Cet article traite de la représentativité des prélèvements d'eau effectués dans le cadre de suivis de bassins versants ou de rivières.Les réflexions proposées sont en premier lieu basées sur des expérimentations de laboratoire et de terrain destinées à comparer divers systèmes et modalités de prélèvements. Les résultats obtenus montrent en particulier que les prélèvements de matières en suspension de dimensions > 100 µm sont peu fiables alors que ce type de particules présente, dans certain cas, une contribution non négligeable aux flux de phosphore total.Les suivis réalisés en divers points représentatifs de petits bassins expérimentaux fournissent des éléments de discussion complémentaires sur le choix des sites des prélèvements et sur les pas de temps de ceux-ci. Nous montrons entre autre, toute l'importance de saisir le début des crues dans les bassins à forte pollution ponctuelle et de considérer des suivis des périodes suffisamment longues pour intégrer les divers fonctionnements hydrochimiques du bassin versant étudié.Water and suspended matter sampling in hydrographic networks is studied through various sampling systems and procedures, and through devices used in fields and in laboratories (fig. 1).Large size particles tend to be underestimated whatever the sampling procedure (manual or automatic) (fig. 2, 3). On the other hand, the sampling for soluble elements and small site particles (less man 50 µm) is very reliable. This is observed in suspended matter concentrations, eg < 2 g.l-1.The largest particles of suspended matter sometimes contribute to nutrient transfer, e.g. phosphorous. This however depends upon the presence of soil microaggregates and nutrient geochemistry. Moreover, natural hydrological variations give rise to another problem for sampling, especially for suspended matter (fig. 7, 9, 10, table 2).Comparatively the variation due to preservation of water is of secondary importance (fig. 11).However, thanks to results from monitoring in experimental watersheds, it is possible to find the best sampling station and the hast time to carry out sampling (fig. 12, 13; fable 3).Duration of survey and intervals between each sample depend, of course, upon the objectives of the study, but also upon watershed characteristics. Considering these characteristics, we propose an example of sampling stategy in the text (table 6, fig. 5)

An Ambient Agent Model for Monitoring and Analysing Dynamics of Complex Human Behaviour

In ambient intelligent systems, monitoring of a human could consist of more complex tasks than merely identifying whether a certain value of a sensor is above a certain threshold. Instead, such tasks may involve monitoring of complex dynamic interactions between human and environment. In order to enable such more complex types of monitoring, this paper presents a generic agent-based framework. The framework consists of support on various levels of system design, namely: (1) the top level, including the interaction between agents, (2) the agent level, providing support on the design of individual agents, and (3) the level of monitoring complex dynamic behaviour, allowing the specification of the aforementioned complex monitoring properties within the agents. The approach is exemplified by a large case study concerning the assessment of driving behaviour, and is applied to two smaller cases as well (concerning fall detection of elderly, and assistance of naval operations, respectively), which are briefly described. These case studies have illustrated that the presented framework enables developers within ambient intelligence to build systems with more expressiveness regarding their monitoring focus. Moreover, they have shown that the framework is easy to use and applicable in a wide variety of domains. © 2011 - IOS Press and the authors. All rights reserved

Reproducibility of lymphovascular space invasion (LVSI) assessment in endometrial cancer

Aims Lymphovascular space invasion (LVSI) in endometrial cancer (EC) is an important prognostic variable impacting on a patient's individual recurrence risk and adjuvant treatment recommendations. Recent work has shown that grading the extent of LVSI further improves its prognostic strength in patients with stage I endometrioid EC. Despite this, there is little information on the reproducibility of LVSI assessment in EC. Therefore, we designed a study to evaluate interobserver agreement in discriminating true LVSI from LVSI mimics (Phase I) and reproducibility of grading extent of LVSI (Phase II). Methods and results Scanned haematoxylin and eosin (H&E) slides of endometrioid EC (EEC) with a predefined possible LVSI focus were hosted on a website and assessed by a panel of six European gynaecological pathologists. In Phase I, 48 H&E slides were included for LVSI assessment and in Phase II, 42 H&E slides for LVSI grading. Each observer was instructed to apply the criteria for LVSI used in daily practice. The degree of agreement was measured using the two-way absolute agreement average-measures intraclass correlation coefficient (ICC). Reproducibility of LVSI assessment (ICC = 0.64, P < 0.001) and LVSI grading (ICC = 0.62, P < 0.001) in EEC was substantial among the observers. Conclusions Given the good reproducibility of LVSI, this study further supports the important role of LVSI in decision algorithms for adjuvant treatment

Bilan du phosphore dans un bassin versant du lac Léman : Conséquences pour la détermination de l'origine des flux exportés

Cet article s'intéresse à la dynamique du transfert du phosphore dans un bassin rural de la région lémanique, le bassin versant du Foron (51,5 km2). Nous montrons qu'en établissant, pour les périodes de tarissement, la relation concentration moyenne en phosphore - débit moyen à l'exutoire, il est possible d'évaluer globalement:1) la rétention du P dans le réseau hydrographique lors de ces périodes; 2) la contribution moyenne des sources ponctuelles de P aux exportations du bassin.La rétention est un phénomène temporaire, mais c'est une étape clé de la dynamique du phosphore. Elle crée d'importants stocks de P dans le réseau hydrographique; ces stocks se situent pour l'essentiel au niveau des sédiments comme l'ont montré diverses études antérieures et sont exportés lors des crues. Les quantités stockées à l'issue de longs étiages dépassent souvent largement les exportations enregistrées pendant les plus fortes crues. La rétention s'accompagne d'une transformation partiellement irréversible de la spéciation du phosphore transféré.Ces phénomènes sont pris en compte pour établir des bilans annuels de pollution, et notamment la balance diffus - ponctuel.The effective management of phosphorus in watersheds requires knowledge of the origin and magnitude of phosphorus inputs. However, for large and complex watersheds, it is impossible to determine the phosphorus mass balances by measuring the flow from each source and the rate of transfer of phosphorus originating from upstream. Because of these difficulties, we have developed a strategy based on the measurement of phosphorus mass balances during base flow periods (with no storm-flow, which means with a constant or decreasing flow). This approach was applied to the Foron River watershed (drainage area 51.5 km2, annual average water discharge 0.5 m3 /s).The Foron River, a hillside stream with a torrential flow regime, is a tributary of Lac Léman (a large meso-eutrophic lake also known as Lake Geneva). Land use within the Foron watershed is diverse, with 50% of the watershed area being in a naturally forested area (on steep upland slopes), 36% in agricultural land lying on a gentle relief of moraine deposits (70% permanent pasture and hay meadows, 30% cereal grain crops) and 3% in marshes. The population is scattered amongst four small villages, with an overall density of about 100 inhabitants per km2. Stream flow in the river was continuously monitored and automatically sampled at the outlet from 1990 to 1993. Additional grab samples were taken at various locations, springs, agricultural sub-watersheds and brooks in the naturally forested area. Total suspended solids, soluble total phosphorus, orthophosphate and total phosphorus were determined according to standard methods. In addition, sampling was carried out to determine phosphorus stored in river sediments in places that are known to be temporary sinks for sediments.To validate the efficiency of the approach, we carried out a detailed study of the point sources and the sewage systems in the watershed. Only two-thirds of domestic wastewaters were processed in treatment plants. The minimum load of point source inputs was established to be about 60 kg total P per week and many point sources (that is to say discharged at discrete locations) remained unidentified (i.e., not all households were connected to sewers, farmsteads contributed for unknown quantities of total P).During base flow periods, phosphorus was predominantly soluble and orthophosphate was found throughout the hydrographic network. Particulate phosphorus and suspended matter concentrations were negligible (respectively 0.8 m3 /s, a constant P export regime was reached as all the inputs were transported to the outlet. Consequently, output at the outlet was equal to input into the river. This approach permits the calculation of the total point sources. Knowing the inputs from point sources and the total P export at the outlet, we can calculate the diffuse sources.Significant relationships between weekly mean total-P, soluble-P or orthophosphate concentrations at the outlet and weekly mean discharge were established to validate these observations. The best fit of these measured values didn't follow a standard law of dilution because the dilution effect was attenuated by the antagonist effect due to the increase in P transport inputs from sewage with increasing discharge. ([soluble P]=0.02+ 0.148 Q-1/2 ; n=82; r2 =0.8).During base flow when Q < 0.8 m3 /s, a portion of phosphorus inputs accumulated in the river biota and sediments through deposition, biological uptake and sorption. This accumulation may explain the higher levels of total-P and the easily exchangeable P in the sediments downstream of point source discharges. The efficiency of these storage processes depends not only on water discharge, but also (secondarily) on some characteristics of the antecedent hydrological conditions. We found that the amount stored increased significantly in the weeks following large storm-flows. We assumed that this indicated the effect of an intense exchange of the P loaded sediments with unsaturated sediments that were generated by erosion of natural upstream areas. As in-stream processes alter phosphorus speciation, a part of soluble-P becomes particulate. During storm-flows following base flow periods with a discharge lower than the limit discharge, the stored phosphorus was released from both particulate and soluble forms and exported. We calculated an annual mass balance of soluble phosphorus to evaluate the amount of particulate phosphorus exported at the outlet due to the transformation of phosphorus from soluble to particulate forms. The result obtained suggested that ¼ of particulate-P (1 t per year) resulted from this speciation change.To summarize, analyses of phosphorus mass balances during base flow could lead to a new procedure to evaluate the mean total mass of P originating from point sources, without referring to field surveys. In addition, this procedure allowed the quantification of both total-P storage as well as changes in speciation that occur during transfer of phosphorus in the hydrographic network