Measuring the monetization strategies of websites with application to pro- and anti-vaccine communities.

Anti-vaccine content and other kinds of misinformation are hypothesized to be more heavily monetized than other kinds of online content. We test this hypothesis by applying several novel and scalable measures of website monetization strategies to more than 400,000 links shared by 261 anti-vaccine Facebook pages and 190 pro-vaccine ones. Contrary to expectations, websites promoted in pro-vaccine venues do more to monetize attention than those promoted in anti-vaccine venues. This is a consequence of how intensely monetized news websites are-pro-vaccine venues share more links to news. The specific news sites shared by anti-vaccine venues are rated less credible by fact-checking organizations, but we find little substantive difference in their monetization strategies. These results emphasize the need to interpret measures of monetization within the context of the broader "attention economy".

xTMS: A Pulse Generator for Exploring Transcranial Magnetic Stimulation Therapies.

A cascaded H-bridge based pulse generator for transcranial magnetic stimulation is introduced. The system demonstrates complete flexibility for producing different shape, duration, direction, and rate of repetition of stimulus pulses within its electrical limits, and can emulate all commercial and research systems available to-date in this application space. An offline model predictive control algorithm, used to generate pulses and sequences, shows superior performance compared to conventional carrier-based pulse width modulation. A fully functioning laboratory prototype delivers up to 1.5 kV, 6 kA pulses, and is ready to be used as a research tool for the exploration of transcranial magnetic stimulation therapies by leveraging the many degrees-of-freedom offered by the design.

Measuring habitat quality for waterbirds: A review.

Quantifying habitat quality is dependent on measuring a site's relative contribution to population growth rate. This is challenging for studies of waterbirds, whose high mobility can decouple demographic rates from local habitat conditions and make sustained monitoring of individuals near-impossible. To overcome these challenges, biologists have used many direct and indirect proxies of waterbird habitat quality. However, consensus on what methods are most appropriate for a given scenario is lacking. We undertook a structured literature review of the methods used to quantify waterbird habitat quality, and provide a synthesis of the context-dependent strengths and limitations of those methods. Our search of the Web of Science and Scopus databases returned a sample of 666 studies, upon which our review was based. The reviewed studies assessed habitat quality by either measuring habitat attributes (e.g., food abundance, water quality, vegetation structure), or measuring attributes of the waterbirds themselves (e.g., demographic parameters, body condition, behavior, distribution). Measuring habitat attributes, although they are only indirectly related to demographic rates, has the advantage of being unaffected by waterbird behavioral stochasticity. Conversely, waterbird-derived measures (e.g., body condition, peck rates) may be more directly related to demographic rates than habitat variables, but may be subject to greater stochastic variation (e.g., behavioral change due to presence of conspecifics). Therefore, caution is needed to ensure that the measured variable does influence waterbird demographic rates. This assumption was usually based on ecological theory rather than empirical evidence. Our review highlighted that there is no single best, universally applicable method to quantify waterbird habitat quality. Individual project specifics (e.g., time frame, spatial scale, funding) will influence the choice of variables measured. Where possible, practitioners should measure variables most directly related to demographic rates. Generally, measuring multiple variables yields a better chance of accurately capturing the relationship between habitat characteristics and demographic rates.

Design Analysis and Circuit Topology Optimization for Programmable Magnetic Neurostimulator.

Transcranial magnetic stimulation (TMS) is a form of non-invasive brain stimulation commonly used to modulate neural activity. Despite three decades of examination, the generation of flexible magnetic pulses is still a challenging technical question. It has been revealed that the characteristics of pulses influence the bio-physiology of neuromodulation. In this study, a second-generation programmable TMS (xTMS) equipment with advanced stimulus shaping is introduced that uses cascaded H-bridge inverters and a phase-shifted pulse-width modulation (PWM). A low-pass RC filter model is used to estimate stimulated neural behavior, which helps to design the magnetic pulse generator, according to neural dynamics. The proposed device can generate highly adjustable magnetic pulses, in terms of waveform, polarity and pattern. We present experimental measurements of different stimuli waveforms, such as monophasic, biphasic and polyphasic shapes with peak coil current and the delivered energy of up to 6 kA and 250 J, respectively. The modular and scalable design idea presented here is a potential solution for generating arbitrary and highly customizable magnetic pulses and transferring repetitive paradigms.

Programmable Transcranial Magnetic Stimulation: A Modulation Approach for the Generation of Controllable Magnetic Stimuli.

OBJECTIVE: A transcranial magnetic stimulation system with programmable stimulus pulses and patterns is presented. The stimulus pulses of the implemented system expand beyond conventional damped cosine or near-rectangular pulses and approach an arbitrary waveform. METHODS: The desired stimulus waveform shape is defined as a reference signal. This signal controls the semiconductor switches of an H-bridge inverter to generate a high-power imitation of the reference. The design uses a new paradigm for TMS, applying pulse-width modulation with a non-resonant, high-frequency switching architecture to synthesize waveforms that leverages the low-pass filtering properties of neuronal cells. The modulation technique enables control of the waveform, frequency, pattern, and intensity of the stimulus. RESULTS: A system prototype was developed to demonstrate the technique. The experimental measurements demonstrate that the system is capable of generating stimuli up to 4 kHz with peak voltage and current values of ±1000 V and ±3600 A, respectively. The maximum transferred energy measured in the experimental validation was 100.4 Joules. To characterize repetitive TMS modalities, the efficiency of generating consecutive pulse triplets and quadruplets with interstimulus intervals of 1 ms was tested and verified. CONCLUSION: The implemented TMS device can generate consecutive rectangular pulses with a predetermined time interval, widths and polarities, enables the synthesis of a wide range of magnetic stimuli. SIGNIFICANCE: New waveforms promise functional advantages over the waveforms generated by current-generation TMS systems for clinical neuroscience research.

A pediatric case of autoresuscitation.

Autoresuscitation (the Larazarus phenomenon) after cessation of cardiopulmonary resuscitation has been systematically reviewed in the adult literature, with only 3 reported cases in pediatrics, although its mechanism remains unclear. We describe a pediatric case of comparatively delayed autoresuscitation with survival far surpassing previously reported pediatric cases.

Measurement of small birefringence and loss in a nonlinear single-mode waveguide.

We design and fabricate a birefringent semiconductor waveguide for application to nonlinear photonics, demonstrating that it is possible to engineer a small birefringence into such a device using multiple core layers. We also demonstrate a simple technique to accurately determine small waveguide birefringence using a differential measurement, present useful methods for coupling light into and out of the device, and make estimates of coupling and linear device losses.

Ultrasound-guided basket retrieval of a submandibular duct stone in a child.

We describe the successful use of ultrasound-guided retrieval of a submandibular stone with a basket, in a 13-year-old child.