High-bandwidth beam balance for vacuum-weight experiment and Newtonian noise subtraction

We report the experimental results of a prototype balance for the Archimedes experiment, devoted to measure the interaction between quantum vacuum energy and gravity. The prototype is a beam balance working at room temperature which shares with the final balance several mechanical and optical components. The balance sensitivity has been tested at the site of the Virgo gravitational wave detector in order to benefit from its quiet environment and control facilities. This allowed also the test of the coherence of the balance data with the Virgo interferometer signal and with the environmental data. In the low-frequency regime, the balance has shown a sensitivity of about $$8\times 10^{-12} {\text {Nm}}/\sqrt{\text {Hz}}$$ 8 × 10 - 12 Nm / Hz , which is among the best in the world, and it is very promising toward the final Archimedes measurement. In the high-frequency region, above a few Hz, relying on the behavior of the balance as a rotational sensor, the ground tilt has been measured in view of the next work devoted to Newtonian noise subtraction (NNS) in Virgo. The measured ground tilt reaches a minimum of about $$8\times 10^{-11} {\text {rad}}/\sqrt{{\text {Hz}}}$$ 8 × 10 - 11 rad / Hz in the few Hz region and ranges from $$10^{-10}$$ 10 - 10 to $$10^{-9} {\text {rad}}/\sqrt{{\text {Hz}}}$$ 10 - 9 rad / Hz in the 10–20 Hz region, where a very interesting coherence, at some frequencies, with the Virgo interferometer signal is shown.

The beam balance – measuring binary systems via relativistic beaming signals from stars and their companions

ABSTRACT In this paper, I show that the concept of relativistic beaming – the process by which light emitted by fast-moving sources is lensed towards the direction of motion – can be easily extended to model the signal from both the star and any secondary companions. Most companions will be cooler and less massive than their host star. Their lower mass leads to faster orbital velocities, and thus a potentially larger beaming effect. The lower temperature will mean that most of their light is emitted at longer wavelengths, where the relative photometric dominance of the primary is reduced. Thus, for some systems, the secondary companion can be the main contributor to observed relativistic beaming signals at long wavelengths. Furthermore, if the system is observed over a range of wavelengths we can independently constrain the temperature of the companion, and the mass and radius ratio of the binary. To conclude, I discuss the current and future observational prospects of this signal, using the properties of known exoplanets to show that such a signal may be observable by upcoming surveys.

Chosen mathematics concepts and their understanding by students of early school education ‒ the concept of measure and measurement

The early school education stage is a particularly important period, in which the child has possibility to confront colloquial and formal knowledge. An important area of such confrontation is the so-called practical information and skills, including the concept of measure and measuring ability. At the elementary level the child passes from colloquial knowledge of measurement to formal knowledge and starts to understand the interrelationships between various measures. One of the basic threats in shaping the concept of measure in children is too early formalization of knowledge. The article presents the results of the pilot studies regarding the understanding by 7‒9 year old children the sense of measuring continuous magnitudes such as: length, volume, mass, time, temperature and surface area. On the basis of the results, it was found that the most difficulties for children is to measure mass, volume and surface area. Basically, the studied group does not understand the importance of balance on the beam balance, so they cannot determine the result of mass measurement. Based on the observation it was noticed that children mostly associate the measuring activity with length and special tools. They are not aware that we can measure with any chosen units and that we can measure different continuous magnitudes.

Relative to Typical Antipsychotic Drugs, Aripiprazole Is a Safer Alternative for Alleviating Behavioral Disturbances After Experimental Brain Trauma

Background. Antipsychotic drugs (APDs) are used to manage traumatic brain injury (TBI)–induced behavioral disturbances, such as agitation and aggression. However, APDs exhibiting D2 receptor antagonism impede cognitive recovery after experimental TBI. Hence, empirical evaluation of APDs with different mechanistic actions is warranted. Aripiprazole (ARIP) is a D2 and 5-hydroxytryptamine1A (5-HT1A) receptor agonist; pharmacotherapies with these properties enhance cognition after TBI. Objective. To test the hypothesis that ARIP would increase behavioral performance and decrease histopathology after TBI. Methods. Adult male rats were subjected to either a controlled cortical impact (CCI) or sham injury and then randomly assigned to ARIP (0.1 or 1.0 mg/kg) or VEH (1.0 mL/kg, saline vehicle) groups. Treatments began 24 hours after surgery and were administered once daily for 19 days. Motor (beam-balance/beam-walk) and cognitive (Morris water maze) performance was assessed on postoperative days 1 to 5 and 14 to 19, respectively, followed by quantification of hippocampal CA1,3 neuron survival and cortical lesion volume. Results. Beam-balance was significantly improved in the CCI + ARIP (1.0 mg/kg) group versus CCI + ARIP (0.1 mg/kg) and CCI + VEH ( P < .05). Spatial learning and memory retention were significantly improved in the CCI + ARIP (0.1 mg/kg) group versus the CCI + ARIP (1.0 mg/kg) and CCI + VEH groups ( P < .05). Both doses of ARIP reduced lesion size and CA3 cell loss versus VEH ( P < .05). Importantly, neither dose of ARIP impeded functional recovery as previously reported with other APDs. Conclusion. These findings support the hypothesis and endorse ARIP as a safer APD for alleviating behavioral disturbances after TBI.

Differences in Maternal Behavior and Development of Their Pups Depend on the Time of Methamphetamine Exposure During Gestation Period

The present study examined the hypothesis that the extension of noxious effect of methamphetamine (MA) on maternal behavior and postnatal development on the pups may differ in dependence with time of application. Female rats were injected with MA (5 mg/kg) or saline during first (embryonic day (ED) 1-11) or second (ED 12-22) half of gestation. Our results demonstrated that MA exposure on ED 12-22 led to decreased birth weight and weight gained during lactation period relative to rats treated on ED 1-11. Both sexes treated prenatally with MA on ED 1-11 opened eyes earlier compared to animals treated on ED 12-22. As a matter of sensorimotor development application of MA on ED 1-11 impaired the righting reflex, while MA exposure on ED 12-22 impaired the performance of beam balance test in male rats. There were no differences in maternal behavior. Therefore, it seems that MA exposure in the first half of the gestation impaired the early sensorimotor development that is under control of the brain stem, while the MA exposure in the second half of gestation affected the beam balance performance that is dependent on the function of the cerebellum.

Reflections on a measurement of the gravitational constant using a beam balance and 13 tons of mercury

In 2006, a final result of a measurement of the gravi- tational constant G performed by researchers at the University of Zürich, Switzerland, was published. A value of G =6.674252(122)×10 −11 m 3 kg −1 s −2 was obtained after an experimental effort that lasted over one decade. Here, we briefly summarize the measurement and discuss the strengths and weaknesses of this approach.

Research on Mechanical Balance of the Beam-Pumper

The detailed analysis of mechanical balance based on beam-pumper is put forward to reduce the motor power, and save consumption. It has discussed something about the analysis of the crack balance, the walking beam balance and the composite balance. Finally, MATLAB M-file editor are used to compile the applications. The simulation results show that the program of the optimal mechanical balance method is feasible.