Is the Stack Distance Between Test Case and Method Correlated With Test Effectiveness?

Mutation testing is a means to assess the effectiveness of a test suite and its outcome is considered more meaningful than code coverage metrics. However, despite several optimizations, mutation testing requires a significant computational effort and has not been widely adopted in industry. Therefore, we study in this paper whether test effectiveness can be approximated using a more light-weight approach. We hypothesize that a test case is more likely to detect faults in methods that are close to the test case on the call stack than in methods that the test case accesses indirectly through many other methods. Based on this hypothesis, we propose the minimal stack distance between test case and method as a new test measure, which expresses how close any test case comes to a given method, and study its correlation with test effectiveness. We conducted an empirical study with 21 open-source projects, which comprise in total 1.8 million LOC, and show that a correlation exists between stack distance and test effectiveness. The correlation reaches a strength up to 0.58. We further show that a classifier using the minimal stack distance along with additional easily computable measures can predict the mutation testing result of a method with 92.9% precision and 93.4% recall. Hence, such a classifier can be taken into consideration as a light-weight alternative to mutation testing or as a preceding, less costly step to that.Comment: EASE 201

Ultrafast electron localization and screening in a transition metal dichalcogenide

The coupling of light to electrical charge carriers in semiconductors is the foundation of many technological applications. Attosecond transient absorption spectroscopy measures simultaneously how excited electrons and the vacancies they leave behind dynamically react to the applied optical fields. In compound semiconductors, these dynamics can be probed via any of their atomic constituents. Often, the atomic species forming the compound contribute comparably to the relevant electronic properties of the material. One therefore expects to observe similar dynamics, irrespective of the choice of atomic species via which it is probed. Here, we show in the two-dimensional transition metal dichalcogenide semiconductor MoSe2, that through a selenium-based transition we observe charge carriers acting independently from each other, while when probed through molybdenum, the collective, many-body motion of the carriers dominates. Such unexpectedly contrasting behavior can be traced back to a strong localization of electrons around molybdenum atoms following absorption of light, which modifies the local fields acting on the carriers. We show that similar behavior in elemental titanium metal carries over to transition metal-containing compounds and is expected to play an essential role for a wide range of such materials. Knowledge of independent particle and collective response is essential for fully understanding these materials

The influence of Karst Aquifer mineralogy and geochemistry on groundwater characteristics: West Bank, Palestine

This work reports, for the first time, the mineralogical and geochemical characteristics of karst aquifers in the Central West Bank (CWB) catchment in Palestine. It provides an integrated study approach by correlating the geochemistry of the lithology and hydrochemical data of groundwater samples. Mineralogical analysis showed that all of the samples were dominantly composed of either calcite CaCO3 (5–100 wt. %) or dolomite CaMg(CO3)2 (4–100 wt. %), with minor amounts of quartz and feldspar, which is supported by the inorganic carbon content (9–13 wt. %) and hydrochemical composition of the spring water samples. The whole-rock geochemical data indicated that the samples have low contents of trace elements and transition metals. In contrast, the concentrations of alkaline earth elements (Mg, Ca, Sr, Ba) and Mn were high in the rock and groundwater samples. Generally, the trace elements of rock samples with concentrations >10 ppm included Sr (17–330 ppm), Mn (17–367 ppm), Ba (2–32 ppm), W (5–37 ppm), Cr (3–23 ppm), Zn (1.7–28 ppm), V (4–23 ppm), and Zr (1–22 ppm), while the concentrations of all the other trace elements was below 10 ppm. Ionic ratios and hierarchical cluster analysis (HCA) suggested that the chemical evolution of groundwater was mainly related to the geogenic (rock–water) interaction in the study area. This is clear in the alkaline earth elements (Mg, Ca, Sr, Ba) ratios, especially regarding the Sr values. The calcite rock samples had higher Sr (mean 160 ppm, n = 11) than those of the dolomite rocks (mean 76 ppm, n = 9)

Compact RF resonator for cryogenic ion traps

We report on the investigation and implementation of a lumped-component, radio-frequency resonator used in a cryogenic vacuum environment to drive an ion trap. The resonator was required to achieve the voltages necessary to trap (about 100 V), while dissipating as little power as possible (< 250 mW). Ultimately a voltage gain of 100 was measured at 5.7 K. Single calcium ions were confined in a trap driven by this device, providing proof of successful resonator operation at low temperature.Comment: 6 pages, 4 figure

Cryogenic Neutron Spectrometer Development

Cryogenic microcalorimeter detectors operating at temperatures around {approx}0.1 K have been developed for the last two decades, driven mostly by the need for ultra-high energy resolution (&lt;0.1%) in X-ray astrophysics and dark matter searches [1]. The Advanced Detector Group at Lawrence Livermore National Laboratory has developed different cryogenic detector technologies for applications ranging from X-ray astrophysics to nuclear science and non-proliferation. In particular, we have adapted cryogenic detector technologies for ultra-high energy resolution gamma-spectroscopy [2] and, more recently, fast-neutron spectroscopy [3]. Microcalorimeters are essentially ultra-sensitive thermometers that measure the energy of the radiation from the increase in temperature upon absorption. They consist of a sensitive superconducting thermometer operated at the transition between its superconducting and its normal state, where its resistance changes very rapidly with temperature such that even the minute energies deposited by single radiation quanta are sufficient to be detectable with high precision. The energy resolution of microcalorimeters is fundamentally limited by thermal fluctuations to {Delta}E{sub FWHM} {approx} 2.355 (k{sub B}T{sup 2}C{sub abs}){sup 1/2}, and thus allows an energy below 1 keV for neutron spectrometers for an operating temperature of T {approx} 0.1 K . The {Delta}E{sub FWHM} does not depend on the energy of the incident photon or particle. This expression is equivalent to the familiar (F{var_epsilon}E{sub {gamma}}){sup 1/2} considering that an absorber at temperature T contains a total energy C{sub abs}T, and the associated fluctuation are due to variations in uncorrelated (F=1) phonons ({var_epsilon} = k{sub B}T) dominated by the background energy C{sub abs}T &gt;&gt; E{gamma}. The rationale behind developing a cryogenic neutron spectrometer is the very high energy resolution combined with the high efficiency. Additionally, the response function is simple and the instrument is transportable. We are currently developing a fast neutron spectrometer with 0.1% energy resolution at 1 MeV neutron energy with an efficiency of &gt; 1%. Our fast-neutron spectrometers use boron-based and {sup 6}LiF absorber crystals with Mo/Cu thermistors readout. They have achieved an energy resolution of 5.5 keV FWHM for 2.79 MeV deposited in {sup 10}B by thermal neutron capture (fig. 1), and 46 keV FWHM for fast (MeV) neutrons absorbed in {sup 6}LiF (fig. 2). Since the energy resolution does not depend on the neutron energy, we expect a similar energy resolution for MeV neutron energies. The response function is given simply by the cross section of the capture reaction, offset from zero by the Q-value of the capture reaction. This allows straightforward discrimination against gamma-events, most of which deposit less that Q{sub 6Li} = 4.79 MeV in the {sup 6}LiF absorber, and easy deconvolution of the neutron spectrum, since there is only a single capture reaction in {sup 6}Li and the spectrum is not affected by edge effects or geometric broadening. The current challenge for microcalorimeters is their necessarily small effective pixel area, {approx}1cm{sup 3} for neutron spectrometer pixels, and their slow decay time, {approx}10ms for neutron spectrometers. The pixel size is limited by the requirement for low Cabs for high energy resolution; the decay time is set by the intrinsically weak thermal coupling between materials at low temperatures. Both issues can be addressed by fabricating large detector arrays. This will enable high-precision neutron spectrometry with high statistics, such as simulated for Pu analysis in fig 3

Creating Conditions for Harnessing the Potential of Transitions to Agroecology in Europe and Requirements for Policy | Création de conditions pour exploiter le potentiel des transitions vers l'agroécologie en Europe et exigences des politiques | Schaffung von Bedingungen für die Nutzung des agrarökologischen Potenzials in Europa und Anforderungen an die Politik

The European Union’s Farm-to-Fork Strategy sets out its ambitions and approach to how European’s value food sustainability, and the accompanying opportunities for improving the environment as well as the lifestyles and health of EU citizens. It identifies the role of agroecological approaches in primary production as one of the means by which these ambitions can be achieved, through new knowledge and innovations in land management and supply chains. This article concludes the Special Issue on the EU Horizon 2020 projects LIFT and UNISECO, synthesising requirements for the realisation of transitions to agroecology in Europe. It reports the key needs identified of developing human capital, partnerships, cooperation and social capital, access to data and tools, and the links between these needs and relevant EU and national level policies.Les systèmes alimentaires doivent être réorientés pour mieux prendre en compte les interactions avec l’environnement, l’économie, la santé et la société. Les transitions vers des pratiques et des systèmes agricoles agroécologiques peuvent relier les domaines de l’action publique et permettre d'atteindre des objectifs environnementaux, économiques et sociaux. Ces transitions fournissent une perspective pour examiner les politiques, les pratiques et les comportements des acteurs des systèmes agricoles et des chaînes de valeur, l’identifi cation des obstacles à l'adoption et les domaines d’action publique auxquels ils contribuent ou qui présentent des lacunes. Le développement du capital social et humain et de structures de gouvernance qui permettent les transitions vers l’agroécologie est la clé de leurs chances de succès. L’éducation et l’apprentissage tout au long de la carrière sont essentiels pour développer les connaissances et les compétences des jeunes générations de gestionnaires fonciers et d’autres acteurs des chaînes de valeur, tout au long de leur carrière. Le résultat recherché est une compréhension partagée des avantages des pratiques et des systèmes agroécologiques, créant des opportunités pour rééquilibrer les politiques vers la neutralité climatique, inverser la perte de biodiversité et renforcer les droits des citoyens. Pour concrétiser ces opportunités, les politiques et stratégies doivent être cohérentes à tous les niveaux territoriaux et systémiques, et adaptées au lieu, au système, aux personnes et aux étapes des transitions. Dans l’ensemble, elles devraient être conçus pour garantir que tous les citoyens bénéfi cient des transitions vers des systèmes agricoles agroécologiques, sur le long terme, et que personne ni aucun lieu ne soit désavantagé par les processus de changement ou les résultats escomptés.Die Lebensmittelsysteme müssen neu ausgerichtet werden, um den Wechselwirkungen zwischen der Umwelt, der Wirtschaft, der Gesundheit und der Gesellschaft stärker Rechnung zu tragen. Die Umstellung auf agrarökologische Anbaumethoden und - systeme kann die Politikbereiche miteinander verbinden und zur Erreichung ökologischer, wirtschaftlicher und sozialer Ziele beitragen. Sie bieten einen Ansatzpunkt für die Überprüfung der Politik, der Praxis und der Verhaltensweisen der Akteure in landwirtschaftlichen Systemen und Wertschöpfungsketten. Des Weiteren helfen sie bei der Ermittlung von Umsetzungsbarrieren und von Politikbereichen, zu denen sie beitragen oder in denen es Lücken gibt. Die Entwicklung von Sozial- und Humankapital sowie von Governance- Strukturen – die den Übergang zur Agrarökologie ermöglichen – sind ein wesentlicher Erfolgsfaktor. Bildung und lebenslanges Lernen sind ein zentraler Baustein, um die Kenntnisse und Fähigkeiten der jüngeren Generationen von Landwirten und Landwirtinnen und anderen Akteuren in den Wertschöpfungsketten zu entwickeln. Das angestrebte Ergebnis ist ein gemeinsames Verständnis über die Vorteile agrarökologischer Praktiken und Systeme. Dieses schafft Möglichkeiten für eine Neuausrichtung der Politik im Hinblick auf Klimaneutralität, Umkehrung des Verlusts der biologischen Vielfalt und Stärkung der Rechte der Bürger. Zur Verwirklichung der Möglichkeiten, sollten Politiken und Strategien über territoriale und Systemebenen hinweg kohärent und auf Ort, System, Menschen und Phasen des Übergangs zugeschnitten sein. Insgesamt sollten sie so konzipiert sein, dass alle Bürgerinnen und Bürger langfristig von der Umstellung auf agrarökologische Bewirtschaftungssysteme profi tieren und dass niemand oder kein Ort durch den Veränderungsprozess oder das angestrebte Ergebnis benachteiligt wird

Entwicklungsszenarien einer alpinen Aue bei einem natürlichen Geschiebedefizit : die Triftaue im Oberhasli

In der zweiten Hälfte des 20. Jahrhunderts hat sich im Zuge des Gletscherrückzugs eine alpine Aue im Triftgebiet gebildet. Zu Beginn prägten dynamische Geschiebeumlagerungsprozesse die Flusslandschaft am Triftwasser und führten zu einer typischen Sukzession einer alpinen Aue. Mit dem weiteren Rückzug des Triftgletschers hat sich Anfang dieses Jahrhunderts der natürliche Triftsee gebildet, der einen Geschiebeeintrag in die darunterliegende Triftaue praktisch vollständig unterbindet. Damit wird die Geschiebedynamik im Triftwasser auf ein absolutes Minimum reduziert. Daher ist es dem Gewässer so gut wie nicht mehr möglich, seinen Verlauf im Zuge von Hochwasserereignissen zu verändern und neue morphologische Strukturen zu bilden. Aufgrund der topografischen Verhältnisse (breiter Kessel) können die natürlicherweise auftretenden Hochwasserereignisse nicht mehr genug Kraft entwickeln, um grossflächige Vegetationsbestände zu entwurzeln. Damit verbunden ist eine rasche Ausbreitung an Grünerlenbeständen, die mittelfristig die heutige Triftaue fast vollständig besiedeln werden. Im Rahmen des Triftprojekts (Vergrösserung des Triftsees mit neuem Kraftwerk auf Höhe der bestehenden Triftfassung) wurden u.a. detaillierte Studien zum Ist-Zustand sowie zur Entwicklung der Triftaue mit und ohne Projekt durchgeführt. Basierend auf diesen Untersuchungen wurden für die Realisierung des Projekts neben dem Restwasserregime zusätzlich auch Hochwasserdotierungen festgelegt

Variability in MRI vs. ultrasound measures of prostate volume and its impact on treatment recommendations for favorable-risk prostate cancer patients: a case series

Background: Prostate volume can affect whether patients qualify for brachytherapy (desired size ≥20 mL and ≤60 mL) and/or active surveillance (desired PSA density ≤0.15 for very low risk disease). This study examines variability in prostate volume measurements depending on imaging modality used (ultrasound versus MRI) and volume calculation technique (contouring versus ellipsoid) and quantifies the impact of this variability on treatment recommendations for men with favorable-risk prostate cancer. Methods: We examined 70 patients who presented consecutively for consideration of brachytherapy for favorable-risk prostate cancer who had volume estimates by three methods: contoured axial ultrasound slices, ultrasound ellipsoid (height × width × length × 0.523) calculation, and endorectal coil MRI (erMRI) ellipsoid calculation. Results: Average gland size by the contoured ultrasound, ellipsoid ultrasound, and erMRI methods were 33.99, 37.16, and 39.62 mLs, respectively. All pairwise comparisons between methods were statistically significant (all p < 0.015). Of the 66 patients who volumetrically qualified for brachytherapy on ellipsoid ultrasound measures, 22 (33.33%) did not qualify on ellipsoid erMRI or contoured ultrasound measures. 38 patients (54.28%) had PSA density ≤0.15 ng/dl as calculated using ellipsoid ultrasound volumes, compared to 34 (48.57%) and 38 patients (54.28%) using contoured ultrasound and ellipsoid erMRI volumes, respectively. Conclusions: The ultrasound ellipsoid and erMRI ellipsoid methods appeared to overestimate ultrasound contoured volume by an average of 9.34% and 16.57% respectively. 33.33% of those who qualified for brachytherapy based on ellipsoid ultrasound volume would be disqualified based on ultrasound contoured and/or erMRI ellipsoid volume. As treatment recommendations increasingly rely on estimates of prostate size, clinicians must consider method of volume estimation