Bringing Back-in-Time Debugging Down to the Database

With back-in-time debuggers, developers can explore what happened before observable failures by following infection chains back to their root causes. While there are several such debuggers for object-oriented programming languages, we do not know of any back-in-time capabilities at the database-level. Thus, if failures are caused by SQL scripts or stored procedures, developers have difficulties in understanding their unexpected behavior. In this paper, we present an approach for bringing back-in-time debugging down to the SAP HANA in-memory database. Our TARDISP debugger allows developers to step queries backwards and inspecting the database at previous and arbitrary points in time. With the help of a SQL extension, we can express queries covering a period of execution time within a debugging session and handle large amounts of data with low overhead on performance and memory. The entire approach has been evaluated within a development project at SAP and shows promising results with respect to the gathered developer feedback.Comment: 24th IEEE International Conference on Software Analysis, Evolution, and Reengineerin

Nebraska Women in Agriculture Conference Marks 39 Years

The Nebraska Women in Agriculture program marked 39 years of educating and empowering females in farming, ranching, and agribusiness, with nearly 380 people attending its annual conference on February 22 and 23, 2024 in Kearney, Nebraska, with a pre-conference session held on February 21. Including 25 workshops, 5 keynotes, and activities to help learn about risk management, farm and ranch improvement, and successful business practices

Teaching dance with mixed reality mirrors : comparing virtual instructors to other forms of visual feedback.

This research aimed to assess whether a virtual instructor and visual feedback combination displayed on a Mixed Reality (MR) mirror can be used to teach a beginner a simple dance routine, replacing the traditional instructor and mirror methods. A prototype was developed using a camera and projector that displayed a digital mirror image of the participant as they learned dances, with the system able to overlay computer graphics onto the image. The camera used to capture the image and motion of the participants was a Microsoft Azure Kinect camera. Three visual feedback types were developed and used as randomized conditions in the user study based on input from expert interviews and an online survey. These were Spheres, Rubber Bands, and Arrows. Three simple dance routines were developed, motion captured, and presented in random order in the user study. During the user study participants learned the dances by following a virtual instructor in the MR mirror (present for each condition), with the MR mirror providing a different form of visual feedback for each dance. After practicing a dance three times with the feedback, participants then performed the dance in front of the MR mirror following the virtual instructor without any feedback, and the system measured the accuracy of their performance by comparing the amount of time that the user’s joints, such as shoulders and elbows, were within desired bounds for each pose. Participants filled out an AttrakDiff Questionnaire describing their experience for each form of feedback, and gave comparative opinions of the different forms of visual feedback in a final interview. The results showed that participants performed best with the Arrows feedback variant which were a directional feedback showing their depth difference, however they ranked this variant the lowest based on their own preference. The most preferred form of feedback was Spheres, which were the simplest feedback, not providing any guidance into the correct pose, but participants performed poorest with them

Unfolding Collapsed Polyelectrolytes in Alternating-Current Electric Fields

We investigate the unfolding of single polyelectrolyte (PE) chains collapsed by trivalent salt under the action of alternating-current (AC) electric fields through computer simulations and theoretical scaling. The results show that a collapsed chain can be unfolded by an AC field when the field strength exceeds the direct-current (DC) threshold and the frequency is below a critical value, corresponding to the inverse charge relaxation/dissociation time of condensed trivalent counterions at the interface of the collapsed electrolyte. This relaxation time is also shown to be identical to the DC chain fluctuation time, suggesting that the dissociation of condensed polyvalent counterion on the collapsed PE interface controls the polyelectrolyte dipole formation and unfolding dynamics under an AC electric field.Comment: 18 pages, 5 figures, submitte

Nanoskopie zur Strukturaufklärung von DNA

Die Verwendung metallischer oder Metall-beschichteter Mess-Sonden für die Rastersondenmikroskopie (SPM – engl. scanning probe microscopy) ist die Voraussetzung für die Kombination mit der Oberflächenverstärkten Raman-Spektroskopie (SERS – engl. surface-enhanced Raman spectroscopy). Bei dem als Spitzenverstärkte Raman-Spektroskopie (TERS – engl. tip-enhanced Raman spectroscopy) bezeichneten Verfahren wird dabei idealerweise nur der endständige Metall-Nanopartikel für die Verstärkung der spezifischen Raman-Informationen genutzt. Durch die geringe Reichweite des zur Detektion genutzten evaneszenten Feldes des bestrahlten Nanopartikels können extrem kleine Bereiche spektroskopisch untersucht werden. Dabei kann Einzel-Molekül-Sensitivität erreicht werden, die gleichzeitig durch die topographische Information der Rastersondenmikroskopie untermauert wird. Diese Eigenschaften der TERS-Technologie schaffen somit das Potential für die Analyse einzelner DNA-Stränge. Im Rahmen dieser Arbeit wurden verschiedene DNA-Proben untersucht. Hierbei konnten zahlreiche Fragestellungen bezüglich der Primär-, wie auch Sekundärstruktur von DNA erstmals mittels TERS adressiert werden. Durch die hoch spezifischen Raman-Informationen der einzelnen DNA-Bestandteile (vornehmlich DNA-Basen) wurde somit der Zugang zu einer umfangreichen zerstörungs-, sowie labelfreien Strukturaufklärung von DNA-aufgezeigt. Ergänzt werden die Ergebnisse zur Strukturaufklärung von DNA durch die Untersuchung von Dünnschnitten behandelter und unbehandelter mit Malaria infizierter Erythrozyten mit Hilfe von TERS. Hierdurch konnte das Potential zur lokal begrenzten Charakterisierung komplexer Proben, wie zellulärer Strukturen, gezeigt werden. Im Einzelnen wurden die spektralen Informationen aus Messungen auf Hämozoin-Kristallen verglichen. Dabei wurden Hinweise auf die oberflächensensitive Wirkungsweise des zur Behandlung verwendeten Anti-Malaria Wirkstoffes Chloroquin gefunden. Charakteristische Raman-Markerbanden, welche die Häm-Dimer-Bildung im Hämozoin anzeigen, wurden im Vergleich zur behandelten Probe deutlich schwächer detektiert

Prof. CI: Employing Continuous Integration Services and Github Workflows to Teach Test-driven Development

Teaching programming using Massive Open Online Courses (MOOCs) is gaining popularity due to their scalability and efficiency of knowledge distribution. However, participating in these courses usually means fully committing to the supplied programming environment in the browser. While this allows a consistent and controllable setup, learners do not gain experience with actual development tools, such as local code editors, testing frameworks, issue trackers or continuous integration (CI) services, which is critical for subsequent real-world projects. Furthermore, the tests for the functionality that is to be developed are oftentimes already available in MOOCs and simply need to be executed, leading to less involvement with developing appropriate tests. In order to tackle these issues while maintaining a high degree of automation and scalability, we developed Prof. CI, a novel approach to conducting online exercises. Prof. CI leverages the existing automation infrastructure that developers use daily, i.e. CI services and Github workflows, to teach test-driven development (TDD) practices. Participants work on their own repositories in Github and receive feedback and new challenges from the CI server when they push their code. We have successfully applied this approach in a pilot project with 30 undergraduate students learning the Ruby on Rails web development framework. Our evaluation shows that the exercise effectively increased students' motivation to write tests for their code. We also present the results of participant surveys, students' experiences and teachers' observations

Adaptive micro axicons for laser applications

We report on the design, fabrication and testing of novel types of low-dispersion axicons for the adaptive shaping of ultrashort laser pulses. An overview is given on the basic geometries and operating principles of our purely reflective adaptive MEMS-type devices based on thermal or piezoelectric actuation. The flexible formation of nondiffracting beams at pulse durations down to a few oscillations of the optical field enables new applications in optical communication, pulse diagnostics, laser-matter interaction and particle manipulation. As an example, we show first promising results of adaptive autocorrelation. The combination of excellent pulse transfer, self-reconstruction properties and propagation invariance of nondiffracting beams with an adaptive approach promises to extend the field of practical applications significantly

Exertional Heat Illness: A Yearly Preventable Cause of Illness and Death in Athletes

Every summer, exertional heat illness in athletes becomes the center of attention among coaches, athletic trainers, and physicians across the United States. This topic has recently received increased attention as seven football players died from exertional heat illness between July 2020 and August 2021[1]. Health professionals believe that sport-related heat illnesses can be prevented through following published sports guidelines, protocols for weather monitoring and water breaks, and using appropriate conditioning during practice sessions. This topic has become such an issue that several states and local governing bodies have enacted legislation and policy for exertional heat illness education and training for coaches, players, and parents[2,3,32]. Every year there are coaches and programs that abstain from following guidelines, disregard weather conditions, and force extreme conditioning, referred to as “irrational intensity”[4]. This blatant disregard for player safety can lead to severe cases of exertional heat illness and even death. The COVID-19 pandemic has had an impact on athletics for nearly two years. When looking at the scope of athletics this upcoming summer, it is reasonable to say that we may be heading towards a return to more typical summer activities. As COVID-19 restrictions loosen, there will likely be an increase in sports participation this summer compared to the summers of 2020 and 2021. Therefore, it is of the utmost importance that the sporting community is educated on a preventable illness that plagues athletes during hot weather seasons. Through education, accountability, enacting protocols, and following guidelines set by health professionals[5-7], we can help prevent these needless cases of severe heat illness and death

Ultrashort vortex pulses with controlled spectral gouy rotation

Recently, the spatio-spectral propagation dynamic of ultrashort-pulsed vortex beams was demonstrated by 2D mapping of spectral moments. The rotation of characteristic anomalies, so-called "spectral eyes", was explained by wavelength-dependent Gouy phase shift. Controlling of this spectral rotation is essential for specific applications, e.g., communication and processing. Here, we report on advanced concepts for spectral rotational control and related first-proof-of-principle experiments. The speed of rotation of spectral eyes during propagation is shown to be essentially determined by angular and spectral parameters. The performance of fixed diffractive optical elements (DOE) and programmable liquid-crystal-on silicon spatial light modulators (LCoS-SLMs) that act as spiral phase gratings (SPG) or spiral phase plates (SPP) is compared. The approach is extended to radially chirped SPGs inducing axially variable angular velocity. The generation of time-dependent orbital angular momentum (self-torque) by superimposing multiple vortex pulses is proposed. © 2020 by the authors

Validity of the Rule of Threes and Anatomical Relationships in the Thoracic Spine

Context The location of the more superficial thoracic spinous processes is used to help osteopathic physicians locate the deeper and more difficult-to-palpate thoracic transverse processes. In 1979, Mitchell et al proposed the thoracic rule of threes to describe the relationship of the spinous processes to the transverse processes in the thoracic spine. This rule is currently taught at osteopathic medical schools. The rule of threes separates the thoracic vertebrae into 3 distinct groups, each with a different relationship between transverse processes and spinous processes. In 2006, Geelhoed et al proposed a new relationship between the spinous processes and transverse processes for all thoracic vertebrae (ie, Geelhoed\u27s rule). Objective To determine which anatomical relationship—the rule of threes or Geelhoed\u27s rule—is most accurate in locating the transverse processes and to define anatomical relationships between thoracic spinous and transverse processes. Methods The thoracic spinous and transverse processes of 44 formalin-embalmed human cadavers were dissected, marked, and photographed. Six different measurements per vertebra were made between spinous processes and transverse processes in the thoracic spine. Geelhoed\u27s protocol was used to determine the validity of each rule. The measurements were analyzed for additional relationships between thoracic spinous processes and transverse processes. Group 1 consisted of vertebrae T1 to T3 and T12; group 2 consisted of T4 to T6 and T11; and group 3 consisted of T7 to T10. Results Of the 528 vertebrae measured, 0% of the first group vertebrae, 10.8% of the second group vertebrae, and 69.3% of the third group vertebrae followed the rule of threes. In total, 26.7% of vertebrae followed the rule of threes, whereas 62.3% of vertebrae followed Geelhoed\u27s rule. Additional relationships worth noting include the distance between the transverse process and the adjacent caudal transverse process on the same side is approximately 25.4 mm (1 inch), and the distance between the transverse processes of the same vertebra is approximately 50.8 mm (2 inches) for male T3-T10 vertebrae and female T1-T12 vertebrae. Conclusion According to our findings, the rule of threes is not as accurate anatomically as Geelhoed\u27s rule in locating the transverse processes of the thoracic spine. This study suggests osteopathic medical schools should teach Geelhoed\u27s rule rather than the rule of threes