bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspects of the cadets’ mental readiness forming during airborne training
Authors: Labeschenkov Oleg , Kuznetsova Zinaida , Zekrin Fanavi , Komarova Svetlana , Kuznetsova Elena
Published: November 2020

The mental readiness formation of cadets’ airborne training in military universities require a special attitude to the functional state indicators. There is a need to develop a specialized method of mental state psychoregulation. The mental readiness formation requires the study of pedagogical, psychological and physiological foundations. A questionnaire survey of the psychoregulation means importance for airborne training was conducted. The cadets give ambiguous answers to the questions of their mental state psychoregulation in airborne training. The first-year cadets have little idea about the mental readiness state, about the means of its regulation. The study of the functional state and body reserve capabilities with the use of innovative accessible and operational methods of rapid diagnostics allows correction of training and psychological effects on cadets. Taking into account physical, mental, and training loads and the tendency to increase them in airborne training requires current and operational control of the functional state. Options for including multidirectional exercises of the mental state psychoregulation in combination with audio sessions on M. A. Bendyukov method in the process of airborne training are considered.
Study on the Technology of Ultra-high Sensitive Wide-band Magnetic-feedback Inductive Magnetic Sensor
Authors: Liu Yong , Li Wenbin , Zhou Jinrong , Pan Rui , Zheng Huan , Xiang Bing , Xu Rui
Published: November 2020

It analyses the composition and principle of high-sensitive wide-band magnetic-feedback inductive magnetic sensor to fulfil the demand of high-sensitive wide-band magnetic sensor in geological exploration. It studies main factors to the performance of wide-band magnetic sensor, such as turns of coils, core material features, and amplifier noise, specifies section-wise coil winding, the type and dimension of core material, and designs low-noise high-impedance LF chopping amplifier channel and composite amplifier with HF amplifier channel. The noise of magnetic sensor at 1 Hz is better than 10-4nT/Hz1/2, at 100Hz-1kHz band the noise floor is close to SQUID which can reach 10-6nT/Hz1/2. The magnetic sensor works at wide frequency band (0.0001Hz-10kHz) and ultra-low noise, which can meet the requirements of both AMT and CSAMT.
Genesungsbegleitung und stationsäquivalente Behandlung
Authors: Schwarz Julian , Geissler Markus , Küsel Madeleine , Müller Katharina , Unterlauf Christin , Bechdolf Andreas , von Peter Sebastian
Published: November 2020

Ziel Untersucht werden die Erfahrungen von Genesungsbegleitenden (GB) in stationsäquivalenten Behandlungsteams nach § 115 d SGB V (StäB).

Methode Im Sinne eines partizipativ-kollaborativen Ansatzes haben Forschende mit und ohne psychische Krisenerfahrung gemeinsam 9 Experteninterviews mit GB aus 7 Kliniken geführt und inhaltsanalytisch ausgewertet.

Ergebnisse Es gibt ein breites Spektrum an Umsetzungsvarianten, Aufgaben und eingenommenen Rollen der GB in den StäB-Teams. GB bieten eine alltagsorientierte, nachhaltige Unterstützung und nehmen dabei oft eine Vermittlerfunktion zwischen den Beteiligten ein. Die Arbeit in StäB wird als weitgehend kooperativ erlebt, wird aber durch strukturelle Herausforderungen auch behindert.

Schlussfolgerung Die Integration von GB in StäB-Teams birgt vielfältige Potenziale für die akutpsychiatrischen Behandlung zu Hause, sollte jedoch umfassend vorbereitet und konzeptionalisiert werden. Außerdem sind Nachbesserungen an den Rahmenbedingungen von StäB notwendig.
Aufenthalte in großen Höhen nach COVID-19-Infektion − neue Aspekte der höhenmedizinischen Beratung
Authors: Grannemann J. J. , Röper A.
Published: November 2020

Nach Lockerung der Reisefreiheit, welche im Rahmen der COVID-19-Pandemie stark eingeschränkt war, ist mit einem wiedereinsetzenden Tourismus auch in hochgelegene Reiseziele über 2500 Meter zu rechnen.

Weiterhin kann man diesem Trend entsprechend davon ausgehen, dass Patienten mit durchgemachter COVID-19-Infektion vor der Reise in große Höhen höhenmedizinische Beratung suchen.

Hier wird der reise- und höhenmedizinisch beratende Arzt vor große Herausforderungen gestellt, da er mit dieser speziellen Fragestellung bisher nicht konfrontiert worden ist.

Dieser Artikel geht neben den Grundlagen der Höhenkrankheit und des Höhenlungenödems auf die aktuelle Studienlage pulmonologischer Pathologien und Krankheitsverläufe bei COVID-19-Infektion ein und gibt entsprechend dem aktuellen Kenntnisstand Empfehlungen zur höhenmedizinischen Beratung von Patienten nach durchgemachter COVID-19-Infektion.
Treatment Landscape and Prognosis After Treatment with Trastuzumab Emtansine
Authors: Laakmann Elena , Emons Julius , Taran Florin-Andrei , Janni Wolfgang , Uhrig Sabrina , Overkamp Friedrich , Kolberg Hans-Christian , Hadji Peyman , Tesch Hans , Häberle Lothar , Ettl Johannes , Lüftner Diana , Wallwiener Markus , Schulmeyer Carla , Müller Volkmar , Beckmann Matthias W. , Belleville Erik , Wimberger Pauline , Hielscher Carsten , Kurbacher Christian , Wuerstlein Rachel , Thomssen Christoph , Untch Michael , Volz Bernhard , Fasching Peter A. , Fehm Tanja N. , Wallwiener Diethelm , Brucker Sara Y. , Schneeweiss Andreas , Lux Michael P. , Hartkopf Andreas D.
Published: November 2020

Purpose Pertuzumab and T-DM1 are two efficient anti-HER2 treatments for patients with HER2-positive advanced breast cancer. While pertuzumab is usually given in first-line
treatment and T-DM1 in second-line treatment, standard therapy options seem to be exhausted up to now after the treatment of patients with these two therapy options. Therefore, it
is important to have data that describes the therapy situation and prognosis after T-DM1 treatment.

Methods The PRAEGNANT metastatic breast cancer registry (NCT02338167) is a prospective registry for breast cancer patients with a focus on molecular biomarkers. Patients of
all therapy lines with any kind of treatment are eligible. Collected data comprises therapies, adverse events, quality of life and other patient reported outcomes. Here we report
on the patient characteristics and descriptive prognostic data for HER2-positive patients who have completed a treatment with T-DM1. Therapy patterns after T-DM1 and
progression-free survival are reported as well as overall survival.

Results A total of 85 patients were identified for the study who were prospectively observed during therapy after the termination of T-DM1. The main reason for T-DM1
termination was progress. Following T-DM1, lapatinib, trastuzumab and chemotherapy were the main therapy choices. Median progression-free survival was 4.8 months (95% CI:
3.2 – 6.3) and median overall survival was 18.4 months (95% CI: 15.5 – 21.3).

Conclusions Therapy options after T-DM1 in a real-world setting seem to exhibit a relevant clinical efficacy, supporting the concept of continuous anti-HER2 treatments in the
advanced therapy setting for breast cancer patients. Novel therapies are needed to improve the rather short median progression-free survival.
N-Arylbenzo[b]phenothiazines as Reducing Photoredox Catalysts for Nucleophilic Additions of Alcohols to Styrenes: Shift towards Visible Light
Authors: Wagenknecht Hans-Achim , Seyfert Fabienne
Published: November 2020

N-Phenylphenothiazines are an important class of photoredox catalysts because they are synthetically well accessible, they allow the tuning of the optoelectronic properties by different substituents, and they have strong reduction properties for activation of alkenes. One of the major disadvantages of N-phenylphenothiazines, however, is the excitation at 365 nm in the UV-A light range. We synthesized three differently dialkylamino-substituted N-phenylbenzo[b]phenothiazines as alternative photoredox catalysts and applied them for the nucleo­philic addition of alkohols to α-methyl styrene. The additional benzene ring shift the absorbance bathochromically and allows performing the photocatalyses by excitation at 385 nm and 405 nm. This type of photoredox catalysis tolerates other functional groups, as representatively shown for alcohols as substrates with C–C and C–N triple bonds.
Surgical Outcomes of Extraforaminal Microdiskectomy by Midline Incision for Far-Lateral Lumbar Disk Herniation
Authors: Yüce Ismail , Kahyaoğlu Okan , Çavuşoğlu Halit , Aydın Yunus
Published: November 2020

Background Far-lateral lumbar disk herniation (FLDH) is defined as a disk herniation located laterally to the medial wall of the pedicle. The aim of our study is to describe the extraforaminal microdiskectomy by midline incision for FLDH, which does not include laminotomy–partial facetectomy, and to evaluate mid-term surgical outcomes.

Methods 107 patients who underwent surgery for FLDH by midline incision for the first time between 2012 and 2017 were included in our study. The assessment of neurological status of the patients was done by physical examination, preoperative Oswestry Disability Index (ODI), Visual Analog Scala (VAS) scores, and magnetic resonance images. They were then followed-up postoperatively and at 12 months with VAS and ODI tests.

Result 58 (54.2%) patients were male and 49 (45.8%) were female. The mean age at the time of surgery was 55.0 ± 8.6 years. The mean ODI scale score was 32.4 ± 6.2 preoperatively, 11.4 ± 2.1 early postoperatively, and 9.7 ± 2.2 in late postoperative follow-up (statistically significant, p = 0.001). The average VAS was 7.51 ± 1.1 preoperatively, 2.74 ± 0.7 early postoperatively, and 0.68 ± 0.08 in late postoperative follow-up (statistically significant, p = 0.001). The average operative time was 41 ± 7 (37 to 58) minutes.

Conclusions The extraforaminal microdiskectomy without laminotomy by midline incision is a minimally invasive approach for FLDH. Our technique allows a sufficient and safe decompression of the neural structures, and thus results in a significant reduction of the symptoms and disability
Contrast-Enhanced Endoscopic Ultrasound for Evaluation of Common Bile Duct in Presence of Portal Cavernoma
Authors: Rana Surinder Singh , Sharma Ravi Kumar , Gupta Rajesh
Published: November 2020

Endoscopic ultrasound (EUS) is an excellent imaging modality for the evaluation of common bile duct (CBD) because of its close proximity to the transducer placed in duodenum. However, in the presence of portal cavernoma, identification and proper evaluation of CBD become difficult because of presence of numerous venous collaterals. In these circumstances, the evaluation of CBD is more difficult if it is nondilated. In these difficult situations, contrast-enhanced EUS can provide better and clear images of CBD and therefore seems to be an excellent modality to evaluate nondilated CBD in the presence of portal cavernoma.
Experience with Management of Intracranial Arachnoid Cysts
Authors: Deopujari Chandrashekhar E. , Shaikh Salman T. , Karmarkar Vikram S. , Sudke Amol Y. , Mohanty Chandan B. , Biyani Naresh K.
Published: November 2020

Objectives The aim of this study was to analyze the demographics, clinical presentation, and surgical outcome of intracranial arachnoid cysts and to review the surgical options.

Methods This is a retrospective observational study of 56 cases of symptomatic arachnoid cysts among all age groups treated between 2004 and 2020 at the Bombay Hospital, Mumbai. Endoscopic fenestration, microsurgical cyst excision, and shunt insertion were the interventions performed. Clinical presentation, cyst reduction post-intervention, and complications were studied. The follow-up period varied from 1 month to 16 years. Statistical analysis was done for 43 patients with a minimum of 3 years' follow-up.

Results In all, 75% of patients were <18 years of age. Of these, the majority were between the age of 1 and 10 years. There were 14 cases of temporal, 13 cases of retrocerebellar, 10 cases of quadrigeminal cistern, and 7 cases each of interhemispheric and suprasellar arachnoid cysts. The most common clinical presentation was headache and vomiting. Concomitant hydrocephalus was seen on imaging in 24 cases. Endoscopic fenestration of cyst was the most routinely performed procedure (35 cases). Four patients of endoscopic fenestration underwent a redo endoscopic procedure on follow-up. Post-operative reduction in cyst size was found to be significantly better after endoscopic fenestration (p < 0.05).

Conclusion Though the best available treatment for arachnoid cysts remains controversial, surgery has been found to be beneficial in symptomatic cases. Endoscopic fenestration is considered the first-line surgical option and it may be followed by shunt, if necessary. Shunts may be preferred in very young children where there is associated hydrocephalus/macrocephaly.
Prospective Evaluation of a Citrate-Based Biomaterial Wedge for a Modified Maquet Procedure in the Treatment of Cranial Cruciate Ligament Rupture in Dogs
Authors: Terreros Alex , Daye R. Mark
Published: November 2020

Objective The aim of this study was to describe short- and mid-term outcomes, complications, implant bioabsorption and owner satisfaction for a modified Maquet procedure (MMP) in which a novel bioabsorbable citrate-based implant is used as the wedge component to treat cranial cruciate ligament rupture in client-owned dogs.

Study Design Prospective clinical study of dogs (n = 13) undergoing MMP (n = 15). Intraoperative complications, postoperative complications, clinical follow-up using a 5-point lameness score and radiographs at 8 weeks and 6 months postoperatively were obtained. Mid-term outcome was assessed via physical examination, radiographs, canine orthopaedic index and owner satisfaction questionnaires.

Results No catastrophic complications occurred. Major complications occurred in 3/15 stifles. All were surgical site infections and one case required implant removal. Minor complications occurred in 9/15 stifles. Non-displaced cortical hinge fractures were the most common minor complication, and these occurred intraoperatively (4/15) or postoperatively (2/15). Three dogs achieved full function, eight dogs acceptable function and the outcome was unacceptable in two dogs. Most owners were satisfied with the procedure (11/13). Complete implant bioabsorption was not confirmed on mid-term radiographs.

Conclusion The described MMP with a citrate-based implant can produce satisfactory mid-term results. However, the long-term outcome of this procedure must be evaluated and technical modifications need to be implemented prior to larger-scale use of this implant.
Acute Provoked Seizures—Work-Up and Management in Adults
Authors: Moosavi Rana , Swisher Christa B.
Published: November 2020

Acute provoked seizures, also known as acute symptomatic seizures, occur secondary to a neurological or systemic precipitant, commonly presenting as a first-time seizure. In this article, we will discuss etiology, emergent protocols, medical work-up, initial treatment, and management of these seizures. The definitions, classifications, and management of convulsive status epilepticus and nonconvulsive status epilepticus in an acute setting will also be reviewed.
Status Epilepticus—Work-Up and Management in Children
Authors: Barcia Aguilar Cristina , Sánchez Fernández Iván , Loddenkemper Tobias
Published: November 2020

Status epilepticus (SE) is one of the most common neurological emergencies in children and has a mortality of 2 to 4%. Admissions for SE are very resource-consuming, especially in refractory and super-refractory SE. An increasing understanding of the pathophysiology of SE leaves room for improving SE treatment protocols, including medication choice and timing. Selecting the most efficacious medications and giving them in a timely manner may improve outcomes. Benzodiazepines are commonly used as first line and they can be used in the prehospital setting, where most SE episodes begin. The diagnostic work-up should start simultaneously to initial treatment, or as soon as possible, to detect potentially treatable causes of SE. Although most etiologies are recognized after the first evaluation, the detection of more unusual causes may become challenging in selected cases. SE is a life-threatening medical emergency in which prompt and efficacious treatment may improve outcomes. We provide a summary of existing evidence to guide clinical decisions regarding the work-up and treatment of SE in pediatric patients.
Is Intracytoplasmic Sperm Injection the Solution for all in Unexplained Infertility?
Authors: Zheng Danni , Nguyen Quynh N. , Li Rong , Dang Vinh Q.
Published: November 2020

Intracytoplasmic sperm injection (ICSI) was first introduced as a supplemental method to conventional in vitro fertilization (c-IVF) for couples with severe male factor infertility to overcome the poor fertilization rate, while its indications expanded in current clinical practice and gained worldwide popularity. However, ICSI is invasive and crosses all natural barriers, raising several unresolved concerns regarding procedure-dependent and procedure-independent risks, as well as the characteristic of being labor-intensive and more expensive than c-IVF. This review is aimed to draw readers' attention, to the widespread use of ICSI worldwide, with its effectiveness in different indications of infertility, especially in those with unexplained infertility, as well as the cost-effectiveness of the ICSI-for-all strategy. Also, we covered current evidence on the short- and long-term safety of children born thanks to ICSI-aided conception. Further well-designed, adequately powered, and randomized controlled clinical trials are absolutely needed to arrive at a consensus on the use of ICSI over c-IVF in different populations.
The Half-Century Mark: Explant of Ball and Cage Valve after 50 Years
Authors: Pupovac Stevan S. , Koss Elana , Hartman Alan R. , Manetta Frank
Published: November 2020

This is a case report of a 69-year-old man with chronic hemolysis and worsening diastolic heart failure, secondary to known periprosthetic leak, who underwent a reoperative mitral valve replacement 50 years following initial implantation of a Starr–Edwards ball and cage valve.
5.1.3 Product Subclass 3: Metalated Germanium Compounds
Authors: Marschner C.
Published: November 2020

This review provides a summary of synthetic approaches to germanides. The described methods involve digermane cleavage, reduction of halogermanes, nucleophilic abstraction of silyl, germyl, or stannyl groups, hydrogermane deprotonation, nucleophilic addition to germylenes, and transmetalation. It covers literature from the 1950s until 2019.
14.10.3 Selenopyrylium and Benzoselenopyrylium Salts (Update 2020)
Authors: Wei W. , Zhao X.
Published: November 2020

This chapter is an update to the earlier Science of Synthesis chapter (Section 14.10) describing methods for the synthesis of selenopyrylium and benzoselenopyrylium salts. It focuses on the literature published in the period 2001–2019.
Effects of Nb doping on switching-voltage stability of zinc oxide thin films
Authors: Li Cheng-Ying , Lin Chun-Cheng , Chu Sheng-Yuan , Lin Jun-Ting , Huang Chih-Yu , Hong Cheng-Shong
Published: November 2020

Nb-doped ZnO (NbxZn1−xO, NZO) thin films with various Nb additions (x = 0, 0.2, 0.5, and 0.8 at. %) were deposited on Pt/TiO2/SiO2/Si substrates by radio frequency magnetron sputtering. The Nb doping concentration was found to affect the microstructure, the number of oxygen vacancies, and work function of the Pt/NZO/Pt structures. Among the various devices, the film with 0.5 at. % Nb addition showed a better switching-voltage stability [i.e., the optimal coefficient of variation (Cv) for reset (7.02%) and set (2.73%) operations, respectively], a high endurance (∼1000 cycles), and lower reset (0.57 V) and set (1.83 V) voltages due to a larger number of oxygen vacancies and a lower work function. In general, the results show that the present NZO thin films are promising candidates for stable and low power-consumption resistive random access memory applications.
Local algebras for causal fermion systems in Minkowski space
Authors: Finster Felix , Oppio Marco
Published: November 2020

A notion of local algebras is introduced in the theory of causal fermion systems. Their properties are studied in the example of the regularized Dirac sea vacuum in Minkowski space. The commutation relations are worked out, and the differences to the canonical commutation relations are discussed. It is shown that the spacetime point operators associated with a Cauchy surface satisfy a time slice axiom. It is proven that the algebra generated by operators in an open set is irreducible as a consequence of Hegerfeldt’s theorem. The light-cone structure is recovered by analyzing the expectation values of the operators in the algebra in the limit when the regularization is removed. It is shown that every spacetime point operator commutes with the algebras localized away from its null cone, up to small corrections involving the regularization length.
Modeling and control of COVID-19: A short-term forecasting in the context of India
Authors: Mandal Manotosh , Jana Soovoojeet , Khatua Anupam , Kar T. K.
Published: November 2020

The coronavirus disease 2019 (COVID-19) outbreak, due to SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), originated in Wuhan, China and is now a global pandemic. The unavailability of vaccines, delays in diagnosis of the disease, and lack of proper treatment resources are the leading causes of the rapid spread of COVID-19. The world is now facing a rapid loss of human lives and socioeconomic status. As a mathematical model can provide some real pictures of the disease spread, enabling better prevention measures. In this study, we propose and analyze a mathematical model to describe the COVID-19 pandemic. We have derived the threshold parameter basic reproduction number, and a detailed sensitivity analysis of this most crucial threshold parameter has been performed to determine the most sensitive indices. Finally, the model is applied to describe COVID-19 scenarios in India, the second-largest populated country in the world, and some of its vulnerable states. We also have short-term forecasting of COVID-19, and we have observed that controlling only one model parameter can significantly reduce the disease’s vulnerability.
In situ investigation of hot-electron-induced Suzuki−Miyaura reaction by surface-enhanced Raman spectroscopy
Authors: Feng Hui-Shu , Dong Fan , Su Hai-Sheng , Sartin Matthew M. , Ren Bin
Published: November 2020

The palladium-catalyzed Suzuki−Miyaura cross coupling reaction is one of the most useful methods for forming carbon—carbon bonds. In addition to traditional thermal activation, plasmonic photocatalysts can also promote this reaction under light illumination. However, it is still debated whether hot electron transfer or localized thermal heating is the main driving force of this reaction. Herein, we utilize in situ surface-enhanced Raman spectroscopy to characterize the Suzuki–Miyaura reaction on the surface of Au@Pd nanoparticles. We exclude the possibility that plasmon-induced heating drives the reaction, and we confirm the hot-electron mechanism by demonstrating a linear relationship between the reaction rate and laser power. Based on these results, we propose that the hot-electron transfer mechanism is the primary route for the plasmon-driven heterogeneous Suzuki−Miyaura cross coupling reaction. These results may help the rational design of photocatalysts.
Studying the physics of charged macromolecules by single molecule fluorescence spectroscopy
Authors: Zhao Jiang
Published: November 2020

It is well documented that conventional methods such as dynamic light scattering have encountered difficulties in characterizing charged macromolecules and, therefore, it is desirable that new methods and techniques are introduced. With the ultra-high sensitivity, single molecule fluorescence spectroscopy has successfully lowered the detection limit considerably and enabled measurement under extreme dilution conditions—around the concentration of 10−9M—at which the effect of inter-chain electrostatic repulsion is suppressed. Furthermore, the excellent spatial and temporal resolution as well as the capacity of molecular recognition of these methods help in obtaining rich information of charged macromolecules. This paper summarizes the applications of single molecule fluorescence spectroscopy, especially fluorescence correlation spectroscopy and photon counting histogram, in the studies on charged macromolecules in aqueous solutions and plenty of new information has been revealed on the molecular conformation, counterion distribution, and a few important governing factors. The powerfulness and effectiveness of single molecule fluorescence spectroscopy make it promising in the investigations of charged macromolecules.
An adaptive and energy-maximizing control optimization of wave energy converters using an extremum-seeking approach
Authors: Parrinello Luca , Dafnakis Panagiotis , Pasta Edoardo , Bracco Giovanni , Naseradinmousavi Peiman , Mattiazzo Giuliana , Bhalla Amneet Pal Singh
Published: November 2020

In this paper, we systematically investigate the feasibility of different extremum-seeking (ES) control and optimization schemes to improve the conversion efficiency of wave energy converters (WECs). Continuous-time and model-free ES schemes based on the sliding mode, relay, least-squares gradient, self-driving, and perturbation-based methods are used to improve the mean extracted power of a heaving point absorber subject to regular and irregular waves. This objective is achieved by optimizing the resistive and reactive coefficients of the power take-off (PTO) mechanism using the ES approach. The optimization results are verified against analytical solutions and the extremum of reference-to-output maps. The numerical results demonstrate that except for the self-driving ES algorithm, the other four ES schemes reliably converge for the two-parameter optimization problem, whereas the former is more suitable for optimizing a single parameter. The results also show that for an irregular sea state, the sliding mode and perturbation-based ES schemes have better convergence to the optimum in comparison to other ES schemes considered here. The convergence of PTO coefficients toward the performance-optimal values is tested for widely different initial values in order to avoid bias toward the extremum. We also demonstrate the adaptive capability of ES control by considering a case in which the ES controller adapts to the new extremum automatically amid changes in the simulated wave conditions. Moreover, no explicit knowledge of (future) wave excitation forces is required in the algorithm, which implies that the model-free ES can be used as a causal controller for WECs. Our results demonstrate that the continuous-time and model-free ES method achieves the optimum within a single simulation, which is in contrast to evolution-based optimization strategies that typically require a large number of (possibly expensive) function evaluations. This makes ES control optimization schemes suitable for nonlinear computational fluid dynamics simulations, where typically evolutionary strategies are used for performing black-box optimization.
1984
Authors: Crane H. Richard
Published: November 2020

A device that merely will give a beep when it is near a piece of metal is simple to make, but it will not satisfy today’s well equipped treasure hunter. What is required now is discrimination between one kind of metal object and another – so the hunter can for example find the coins among bottle caps and pull tabs. The discrimination is tricky, and it is accomplished in several different ways. Here I will describe one of the ways – the one that seems to me to be the most sophisticated – and leave to a future column a simpler method, along with some words about the close parallels among methods of hunting treasure, detecting nuclear magnetic resonance, measuring the frequencies of resonant circuits and, according to recent ads, locating the studs in a wall.
1987
Authors: Crane H. Richard
Published: November 2020

Remember the discussion of the popular automatically focusing personal 35-mm cameras? Automatic focusing of a more sophisticated kind has entered the movie-making industry, and it accounts for some shots that would be next to impossible without it. An example would be the problem of following an actor running and dodging through a crowd and keeping him in perfect focus all the time. In the new scheme, a microwave radio transmitter at the camera sends out continuously a series of pulses—short trains of waves. The runner has on his person a match-box size transponder, a device that receives the pulses and retransmits them instantly, shifted in wavelength. The equipment at the camera receives the retransmitted pulses, and in its microprocessor circuits translates the time difference between the outgoing and returning pulses into a distance setting for the lens. Everything is automated right down to the motorized focusing movement of the lens—everything, that is, except for pointing the camera. (That, at least, remains as something for the cameraman to do!) Not only does the focus follow almost instantaneously, it is single-minded—ignoring everything but the actor who has the transponder.
1988
Authors: Crane H. Richard
Published: November 2020

Columbus used a magnetic compass on his voyage to the new world in 1492. Magellan embarked on his round-the-world voyage in 1519 under guidance of a compass. The compass of that day was simply a needle on a pivot, the needle having been magnetized by rubbing it on a lodestone. Except for a few mechanical improvements, that instrument remained the same through the centuries until recent times. Despite its simplicity, it was an excellent indicator of magnetic direction for ships on the high seas as long as ships were constructed of wood. Problems arose as the wood was replaced by steel. The first solution was to locate the compass needle as far away from the bulk of the steel as possible, for instance on a high mast. The direction that the needle was pointing was sensed by a Photoelectric eye or other means, and the information was transmitted by wire to a readout device in front of the pilot’s eyes. This system works, but it has some problems stemming from the necessity of having the delicate compass needle unattended in a remote place.
INTRODUCTION
Authors: Feltyberger Earl R. , Mallmann James , Schmidt Judy M. , Senior Thomas
Published: November 2020

As long as we have been attending AAPT conventions, we have been observing beautiful and simple introductory experiments in electric circuits and electronics presented by high school and college teachers. But these experiments have not been duplicated in high school or college lab rooms or introductory physics laboratory manuals. And these demonstrations and experiments are not being copied in high schools and colleges either. Why not? From the testimony of the teachers we have talked to (and from our own experiences), we have come to the conclusion that many (most?) introductory physics teachers have not had enough hands-on experience with electric circuits to feel confident in presenting this material to their students. So this workshop is intended for all of those under-confident teachers (and we include ourselves in this group).
BACKGROUND INFORMATION ON THE EXPERIMENTS
Authors: Feltyberger Earl R. , Mallmann James , Schmidt Judy M. , Senior Thomas
Published: November 2020

This experiment is designed to show that electric fields (a topic that should have been developed during the study of static electricity) can be used to explain the operation of simple electric circuits. The experiment begins with an explanation of using energy differences per unit charge (voltage) to map a field. It then proceeds to a description of experimental set-up and suggests several different fields that should be investigated. The last part of the experiment, in which light bulbs are substituted for water, is intended to show students that electric fields are involved in important tasks, such as lighting light bulbs.
COMPUTER APPLICATIONS
Authors: Feltyberger Earl R. , Mallmann James , Schmidt Judy M. , Senior Thomas
Published: November 2020

Computers, when properly interfaced to experiments, can collect data more accurately and quicker than human beings can. Two of the experiments in this workshop were performed with computers as data logging and analysis instruments. The results are presented below.
TEST QUESTIONS
Authors: Feltyberger Earl R. , Mallmann James , Schmidt Judy M. , Senior Thomas
Published: November 2020

If an electron were placed midway between plates A and B, as in Fig. 1 above, the electron would move in which direction?
Introduction
Authors: Nelson Jane Bray , Nelson Jim
Published: November 2020

The physicist in each of us wants to explain the natural world we observe. However, before any explanations can be attempted, accurate observations must be made of what we wish to explain. An observation is a record of what your senses tell you about the natural world. Very often, these observations are expressed as measurements. When a measurement is made, a number with a unit is associated with the observation. For example, when someone says “1.2 seconds,” “1.2” is the number, and “seconds” is the unit. Consider another example: a car is going very fast, but a measurement of speed is needed to determine if a speeding ticket is appropriate. The importance of measurement for understanding the natural world is nicely expressed by the following:“When you can measure what you are speaking about and express it in numbers, you know something about it; and when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the stage of a science.”— Lord Kelvin (1824–1907)
Time
Authors: Nelson Jane Bray , Nelson Jim
Published: November 2020

The following activities are presented: Activity 1. Significant Times: Measuring Clap Time Interval with a Stopwatch.Activity 2. Making a One-Second Timer.Activity 3. Pendula on Parade.Activity 4. Investigation of a Flashing Light.Miscellaneous Demonstrations and Activities for the Study of Time.
Exploring Laser Light
Authors: Kallard T.
Published: November 2020

The low-power helium-neon (He-Ne) gas laser is an invaluable and dependable educational tool, used at all levels from high school physics to complex university installations. Exploring Laser Light is a manual of optics experiments performed with He-Ne lasers, for use in lecture demonstrations, teaching laboratories, and home study experimentation.

Key highlights:Offers a broad selection of the most robust optical principles and techniquesExplores fresh and simplified experimental methodsRather than offering a rigid approach, the range and choice of optical bypaths covered point the way for readersTo help the experimenter, schematic drawings are included, alongside relevant formulas and numerical values for parametersThe cost of required apparatus is deliberately kept to a minimum

Exploring Laser Light is the ideal resource for the home experimenter as well as the high school physics teacher. Undergraduates to advanced graduate students and faculty in optics, physics will as well benefit.
The Optical Bench and Basic Accessories
Authors: Kallard T.
Published: November 2020

The basic components needed to perform the exercises and lecture demonstrations described in this book are listed below.
Laser Power Meters and Detectors
Authors: Kallard T.
Published: November 2020

Most photodetectors and light meters designed either for photographic use or in physical science laboratories, will respond to a laser beam and may be used to give indications of relative brightness of the beam in direct current and low frequency modulation applications. However, most of these units are unsatisfactory for quantitative work with lasers because of range limitations, aperture size, and other design factors.
Beamsplitters
Authors: Kallard T.
Published: November 2020

Beamsplitters divide an input light beam into two components. The output components emerge in different directions - usually at right angles to each other. The relative intensities of the two emergent light beams are fixed by the characteristic of the beamsplitter, that is, a beamsplitter is capable of reflecting and transmitting an incoming beam in a certain characteristic ratio. This reflection/transmission ratio (R/T) is usually expressed in a percentage. A description of some of the more often used beamsplitters follows…
Arrangement for Measuring Vibrations of a Rotor Axle
Authors: Kallard T.
Published: November 2020

In Figure 58 the laser beam is expanded by means of the optical system L1 and L2 The expanded and collimated laser beam travels toward the test object T (rotor axle, elastic vibrator reed, etc.) and the light rays which pass by the object are focused through L3 on a photodiode PD or other type photodetector.
Remotely Sensing Tachometer
Authors: Kallard T.
Published: November 2020

A small stainless steel mirror is attached to the end of the rotating shaft as shown in Fig. 60. A laser beam is reflected off this plane mirror on to a photodetector (PD). Half of the mirror is blacked, so that as the shaft rotates a current of approximately square wave form is generated in the photodetector.
Determination of Focal Length of a Convex Lens by Autocollimation
Authors: Kallard T.
Published: November 2020

To find the focal length, f, of a positive lens, the apparatus is arranged as shown in Fig. 83. The laser, the object-image screen, the lens, and a front-surface plane mirror are mounted on an optical bench. The object-image screen is a white, 7.5 cm x 12.5 cm (3” x 5”) filing card. A small hole is punched in the center of the card and a piece of tracing paper is fastened with adhesive tape to cover the hole. The raw laser beam is aimed to impinge on the center of the tracing paper. The bright red spot on the translucent paper is the “object”. The lens to be measured and the plane mirror are set up close together. The light leaving the lens is interrupted by the mirror whose reflective surface is approximately square to the laser beam axis. If the tracing paper is situated exactly in the principal focal plane of the lens and the mirror is exactly at right angles to the laser beam axis than the light rays are reflected back exactly upon their original paths. If, however, the mirror is inclined at a small angle, T, to the axis, the incident light rays are reflected back at an angle, 2T, and the image of the bright red spot will be formed on the white card screen instead of the tracing paper. By sliding the lens-mirror combination back and forth along the axis a sharp image of the bright spot is obtained on the white card. The distance between the card (object-image screen) and the lens is the focal length.
Fingerprint Observation by Frustrated Total Reflection
Authors: Kallard T.
Published: November 2020

When total internal reflection occurs in a medium, radiation can penetrate slightly beyond the reflecting surface into a rarer medium. This phenomenon of penetration can be utilized to frustrate the total reflection completely at the points of intimate contact of an external body brought into close proximity and coupled with the totally reflecting surface from the side of the rarer medium. At the point of contact the radiation will penetrate into the contacting opaque body where it will be absorbed. In this manner total reflection is frustrated at the points of contact.
Piezoceramic Bender Elements that Control Laser Beams
Authors: Kallard T.
Published: November 2020

Piezoceramic bender elements consist of two thin rectangular piezoceramics with their poled axes perpendicular to their electrode surfaces. These piezoceramics are assembled and bonded with epoxy cement to form an alternating polarity bilaminar element. The two layers are polarized in opposite directions. The application of an electric field across the two outer electrodes causes one layer to expand while the other contracts. Thus, the composite element curls and the resulting bending displacement is much larger than the length deformation of either of the two layers. The operation of the bender in response to an electric field is analogous to a temperature change on a bimetallic thermostat.
Simple Polarization Demonstrations
Authors: Kallard T.
Published: November 2020

The Lazy Susan setup used in the following demonstrations is the same as the one used before for ray-optics exercises. The direct beam from a low-power He-Ne laser is passed through a short-focus cylinder lens (a glass or plastic rod of 2-4 mm diameter). The transparent rod is mounted on, or near, the laser housing where the beam exits from the laser. The light emerging from the rod is fan shaped. The rod is oriented horizontally and this results in a thin vertical sheet of light which cuts across the horizontal plane of the Lazy Susan table, producing a bright ray streak on the table. Between the laser and the Lazy Susan table there is a short (25 cm) optical bench to carry polarizers and retardation plates.
Scattering of Light and Polarization
Authors: Kallard T.
Published: November 2020

The polarization of the light from an unpolarized beam that is scattered by a suspension of fine particles can be demonstrated with any one of the arrangements shown in Fig. 120.
Projecting Crystal Patterns in Convergent Light
Authors: Kallard T.
Published: November 2020

Polarized light is used extensively in the field of mineralogy. The patterns produced by transparent specimens cut into a thin plate, placed between two polarizers, and illuminated with monochromatic convergent light, are instructive when making comparisons of the symmetries of different types of crystals. The patterns projected (or photographed) indicate whether the crystal is (a) uniaxial or biaxial, (b) if uniaxial, where the optic axis is, and (c) if biaxial, the angle between the optic axes.
Collimation Tester
Authors: Kallard T.
Published: November 2020

The collimation tester is a simple tool for adjusting laser collimator focus and for testing the planeness of a wavefront interferometrically.

Interference fringes are formed upon reflection of a laser beam from the front and back surfaces of a narrow wedge plate of glass. The same phenomenon can be observed with a thin film of air contained between two plane glass plates at a small angle to each other.
The Optical Doppler Radar
Authors: Kallard T.
Published: November 2020

In 1842 Christian Johann Doppler, the Austrian mathematician and physicist advanced the theory: The frequency of a radiation will shift if its source or receiver is in motion. Doppler’s theory was first verified in acoustics with the discovery that the speed of motion of a sound’s source or its receiver, bore a direct relationship to the speed of the sound’s propagation. That familiar change in a sound’s pitch when its source or hearer is moving is known now as the Doppler effect.
Point-of-Sale Label Reading
Authors: Kallard T.
Published: November 2020

The technical term ‘point-of-sale’ (POS) means the time and place at which the customers hand over their money to the cashier in a retail establishment, or the checkout counter in a supermarket.
String and Sticky Tape Experiments
Authors: Edge R. D.
Published: November 2020

Physics is an experimental science, and the only way to get a feel for it is by doing hands-on experiments. However, experimenting with expensive physics equipment in schools is not an option for students. String and Sticky Tape Experiments brings together a host of experiments demonstrating fundamental physics laws in a practical way that students can work with on their own. Materials are deliberately chosen for their simplicity, availability, and low cost, so they can be done at home as well as at school.

Many of these experiments were published in the American Association of Physics Teachers’s journal The Physics Teacher.

String and Sticky Tape Experiments organizes and ranks experiments by Subject: Mechanics, Properties of Matter, Hydrodynamics, Heat, Wave Motion, Light, Sound, Atomic and Nuclear Physics, Solid State and Crystallography, Electrostatics, Magnetism, Current Electricity, Psychophysics, and Physics GamesDifficultyEducational levelQualitative or quantitative natureFundamental natureEntertainment value

Students across all physics disciplines and at all levels will learn and gain enjoyment from this book, from elementary level to high school and university. It is also a valuable resource for physics teachers.
Mechanics
Authors: Edge R. D.
Published: November 2020

We will start our experiments by measuring accuracy. Lord Kelvin said:“I often say that when you can measure what you are speaking about, and express it in numbers, you known something about it; but when you cannot express it in numbers your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of Science, whatever the matter may be.”
Properties of Matter
Authors: Edge R. D.
Published: November 2020

Experiment 2.01 Properties of matter-stress and tension in chalk
Hydrodynamics
Authors: Edge R. D.
Published: November 2020

Experiment 3.01 Hydrostatics and Hydrodynamics - Hydrostatic Pressure
Atomic and Nuclear Physics
Authors: Edge R. D.
Published: November 2020

Experiment 8.01 Molecular size

Equipment: Soap, chalk dust, wash bowl.
Electrostatics
Authors: Edge R. D.
Published: November 2020

One of the problems in devising experiments employing cheap and easily available materials has been to find equipment for electrical experiments - particularly electrostatic experiments. The most satisfactory solution appears to be the (empty) aluminum soft drink (or beer!) can (12 oz) which can be used for inumerable purposes. Unlike the old steel cans, the aluminum may be cut easily with a pair of scissors, and without ruining the scissors. The edges of the cut metal are not as sharp as the steel cans, and the sheet can easily be bent with the fingers - yet it is robust enough, unlike aluminum foil, to retain the shape which it is given, even under stress. This item of garbage must definitely be added to our list of resource materials.
Psychophysics
Authors: Edge R. D.
Published: November 2020

Experiment 13.01 Benham’s Top - an experiment in psychophysics.

Materials: straw