For a graph G, a subset S subset of V (G) is called a resolving set of G if, for any two vertices u, v is an element of V (G), there exists a vertex w is an element of S such that d(w, u) not equal d(w, v). The METRIC DIMENSION problem takes as input a graph G on n vertices and a positive integer k, and asks whether there exists a resolving set of size at most k. In another metric-based graph problem , GEODETIC SET, the input is a graph G and an integer k, and the objective is to determine whether there exists a subset S subset of V (G) of size at most k such that, for any vertex u is an element of V (G), there are two vertices s(1), s(2) is an element of S such that u lies on a shortest path from s(1) to s(2). These two classical problems are intractable with respect to the solution size, as well as most structural parameters, including the feedback vertex set number and pathwidth. The very few existing tractable results state that they are both FPT with respect to the vertex cover number vc. Specifically, we observe that both problems admit an FPT algorithm running in 2(O(vc2)) . n(O(1)) time, and a kernelization algorithm that outputs a kernel with 2(O(vc)) vertices. For these problems, we also prove that, unless the Exponential Time Hypothesis fails, the established running time is asymptotically the best possible. (c) 2026 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
This study evaluated the performance of two portable spectral devices (visible: Vis; near-infrared: NIR) and one benchtop combined Vis/NIR instrument for predicting beef biochemical traits related to meat quality. A total of 497 muscle samples were collected from 55 fattening farms across five European countries. Reference values were obtained exclusively from pooled samples. For the benchtop device, two sampling strategies were compared: 1) direct scanning of pooled samples (n = 99) used for reference analyses, and 2) scanning individual samples followed by spectral averaging to match pooled references. Partial least squares regression models were developed using several preprocessing methods. For total and heme iron, predictive performance was also evaluated by separately analyzing the visible region of the benchtop device. Results showed that the benchtop Vis/NIR instrument clearly outperformed the portable devices, providing higher prediction accuracies for all traits across the full spectral range. Compared with portable instruments, the benchtop device achieved superior performance for proximate composition (R-2 = 0.51-0.85 vs 0.10-0.22), major fatty acids (R-2 = 0.50-0.68 vs 0.01-0.31), and total and heme iron (R-2 = 0.79-0.93 vs 0.46-0.91). Moreover, scanning individual samples and averaging spectra yielded better prediction models than direct scanning of pooled samples, with good accuracies for moisture, protein, fat content, major saturated and monounsaturated fatty acids, and iron. Conversely, poor prediction (R-2 < 0.40) was observed for polyunsaturated fatty acids, TBARS, carnosine, anserine, zinc, selenium and B-group vitamins. Overall, Vis/NIR spectroscopy showed strong potential for beef quality assessment, although further optimization is required for portable devices.
This paper evaluates the impact of a pilot innovative project aiming at promoting a replicable model to create access to distributed electricity in rural areas where grid extension is economically infeasible. The project proposes building solar-powered micro-grids to provide affordable electricity and basic electricity services to households, businesses, and public services. The pilot nature of the project was conceived to facilitate a rigorous testing of its developmental impacts, contrasting with the existing evaluation literature, which provides at best descriptive conclusions. The evaluation methodology is based on a randomized control trial (RCT) design, with data collected before and after project implementation through two waves of household surveys in 2017-2018 and 2023, complemented by locality data. The experimental dimension of the paper is based on a treatment implemented at the locality level. A dozen of comparable localities had been initially selected after a common pre-feasibility study as suitable for the project, and the project has been randomly implemented in only half of them. Findings reveal notable improvements in household access to electricity, particularly in the use of modern energy services like lighting and phone charging. The project has also triggered nascent new economic activities, especially secondary income-generating occupations, though the overall impact on household wealth remains limited. Social outcomes have seen mixed results, with only significant improvements in health and none in education. Complementary actions mentioned in the project's theory of change but not fully implemented may be needed to achieve the broader economic and social transformation initially anticipated.
Although the effects of the presence of others on behavior constitute one of the oldest topics studied in social psychology, the reason why these effects occur is still the subject of scientific debate. Three hypotheses are commonly cited: (1) the presence of others facilitates dominant responses by increasing arousal, (2) it captures attention, or (3) it increases the efforts of those being observed. Few studies have attempted to distinguish between these explanations, and those that have done so have used a specific paradigm: the Stroop task. In the present study, we proposed an alternative approach based on the use of the temporal bisection task. In three studies, the bisection results showed a temporal shortening effect in social presence (that of an experimenter) consistent with an attentional distraction-related effect. Our results also provided the first evidence that this effect may be stronger when the attentional conflict between the task and the presence is unimodal (e.g., visual task and visual presence) rather than cross-modal (e.g., auditive task and visual presence). They also suggested that the social presence effect might be similar to that produced by a mechanical distractor, although the social nature of the distractor increased the attention-related effect. We discuss how variations in the presence and behavior of the experimenter could contribute to the difficulty of replicating certain studies in experimental psychology, given that the social presence of the experimenter is generally assumed to be innocuous.
Despite the growing importance of wellness and health tourism, little is known about how individuals who have never experienced thermal spa treatments form intentions toward such services. This study addresses this gap by mobilizing an extended Theory of Planned Behavior framework enriched with subjective knowledge and expected health benefits. Based on a large-scale survey of French non-users, we combine Partial Least Squares Structural Equation Modelling and Necessary Condition Analysis to examine both enabling and constraining mechanisms of intention formation. The results show that all predictors contribute positively to intention, with subjective norm emerging as the most influential factor. However, the necessity analysis reveals a markedly different causal structure: only subjective norm, expected health benefits, and perceived behavioral control establish threshold conditions that must be satisfied for higher levels of intention to occur. In contrast, subjective knowledge and attitude, although significant, do not operate as indispensable conditions. These findings reveal an asymmetry between the factors that raise intention and those that set the threshold for it. They suggest that, in this context, intention depends on socially mediated validation, not on individual evaluation alone. For managers, the priority is the conditions that must be met for intention to form - social legitimacy, credible health benefits, and feasibility - rather than interventions, such as information or persuasion, that intensify intention only once those conditions are in place.
