The utility of behavioral biometrics in user authentication and demographic characteristic detection: a scoping review.

BACKGROUND: Objective measures of screen time are necessary to better understand the complex relationship between screen time and health outcomes. However, current objective measures of screen time (e.g., passive sensing applications) are limited in identifying the user of the mobile device, a critical limitation in children's screen time research where devices are often shared across a family. Behavioral biometrics, a technology that uses embedded sensors on modern mobile devices to continuously authenticate users, could be used to address this limitation. OBJECTIVE: The purpose of this scoping review was to summarize the current state of behavioral biometric authentication and synthesize these findings within the scope of applying behavioral biometric technology to screen time measurement. METHODS: We systematically searched five databases (Web of Science Core Collection, Inspec in Engineering Village, Applied Science & Technology Source, IEEE Xplore, PubMed), with the last search in September of 2022. Eligible studies were on the authentication of the user or the detection of demographic characteristics (age, gender) using built-in sensors on mobile devices (e.g., smartphone, tablet). Studies were required to use the following methods for authentication: motion behavior, touch, keystroke dynamics, and/or behavior profiling. We extracted study characteristics (sample size, age, gender), data collection methods, data stream, model evaluation metrics, and performance of models, and additionally performed a study quality assessment. Summary characteristics were tabulated and compiled in Excel. We synthesized the extracted information using a narrative approach. RESULTS: Of the 14,179 articles screened, 122 were included in this scoping review. Of the 122 included studies, the most highly used biometric methods were touch gestures (n = 76) and movement (n = 63), with 30 studies using keystroke dynamics and 6 studies using behavior profiling. Of the studies that reported age (47), most were performed exclusively in adult populations (n = 34). The overall study quality was low, with an average score of 5.5/14. CONCLUSION: The field of behavioral biometrics is limited by the low overall quality of studies. Behavioral biometric technology has the potential to be used in a public health context to address the limitations of current measures of screen time; however, more rigorous research must be performed in child populations first. SYSTEMATIC REVIEW REGISTRATION: The protocol has been pre-registered in the Open Science Framework database ( https://doi.org/10.17605/OSF.IO/92YCT ).

Early-stage studies to larger-scale trials: investigators' perspectives on scaling-up childhood obesity interventions.

BACKGROUND: Pilot/feasibility studies play an important role in the development and refinement of behavioral interventions by providing information about feasibility, acceptability, and potential efficacy. Despite their importance and wide-spread use, the approaches taken by behavioral scientists to scale-up early-stage studies to larger-scale trials has received little attention. The aim of our study was to understand the role that pilot studies play in the development and execution of larger-scale trials. METHODS: We conducted interviews with childhood obesity researchers who had published pilot behavioral interventions and larger-scale trials of the same or similar interventions. Questions were asked about the role of pilot studies in developing larger-scale trials and the challenges encountered when scaling-up an intervention based upon pilot findings. Data were coded and analyzed using an inductive analytic approach to identify themes. RESULTS: Twenty-four interventionists (54% women, 37-70 years old, mean 20 years since terminal degree) completed a total of 148 pilot studies across their careers (mean 6.4, range 1-20), of which 59% were scaled-up. Scaling was described as resource intensive and pilot work was considered essential to successfully competing for funding by 63% of the sample (n = 15). When asked to define a high-quality pilot study, interventionists described studies that allowed them to evaluate two independent factors: components of their intervention (e.g., acceptability, feasibility) and study parameters (e.g., sample size, measures). Interventionists expressed that more process implementation measures, different study designs, and additional iterations could improve decisions to scale-up. Most agreed that pilot studies were likely to produce inflated estimates of potential efficacy though only nine interventionists provided potential solutions for decreasing inflated measures of efficacy. Suggested major causes of inflated effects included high levels of oversight in pilot studies (e.g., researcher support), reliance on subjective measures, and utilizing convenience or highly motivated samples. Potential solutions included designing pilots for real-world implementation, only conducting randomized controlled pilot studies, and pre-registering pilot studies. CONCLUSIONS: Pilot studies purposes are multifaceted and deemed essential to obtaining funding for larger-scale trials. Clarifying the form and function of preliminary, early-stage research may enhance the productive utilization of early-stage studies and reduced drops in efficacy when transitioning to larger scale studies.

A Rare Differential Diagnosis of a Nasal Tumor: Case Report and Literature Review.

Vascular leiomyomas or angioleiomyomas are rare tumors that can be found in the nasal cavity. The etiology of angioleiomyoma remains poorly understood and there are several hypotheses to explain the origin of sinonasal leiomyoma. We here describe the clinical and histological findings in a case study along with the feasibility of surgical treatment using a radiofrequency instrument. In particular, we describe the case of an adult patient with recurrent epistaxis because of a nasal angioleiomyoma and the performed treatment in the form of complete surgical excision. Radiological imaging is a helpful tool to give an indication of the extension of the tumor, as well as for the proper planning of the surgical approach. Either MRI or CT scans are found to be best suited for this purpose. This case report recommends the complete surgical excision of the angioleiomyoma, by either an endoscopic or an open procedure. This can be safely performed using a radiofrequency instrument as shown in this case with no recurrence during a follow-up of 12 months.

Elevated CO2 effects on canopy and soil water flux parameters measured using a large chamber in crops grown with free-air CO2 enrichment.

An arable crop rotation (winter barley-sugar beet-winter wheat) was exposed to elevated atmospheric CO(2) concentrations ([CO(2) ]) using a FACE facility (Free-Air CO(2) Enrichment) during two rotation periods. The atmospheric [CO(2) ] of the treatment plots was elevated to 550 ppm during daylight hours (T>5°C). Canopy transpiration (E(C) ) and conductance (G(C) ) were measured at selected intervals (>10% of total growing season) using a dynamic CO(2) /H(2) O chamber measuring system. Plant available soil water content (gravimetry and TDR probes) and canopy microclimate conditions were recorded in parallel. Averaged across both growing seasons, elevated [CO(2) ] reduced E(C) by 9%, 18% and 12%, and G(C) by 9%, 17% and 12% in barley, sugar beet and wheat, respectively. Both global radiation (Rg) and vapour pressure deficit (VPD) were the main driving forces of E(C) , whereas G(C) was mostly related to Rg. The responses of E(C) and especially G(C) to [CO(2) ] enrichment were insensitive to weather conditions and leaf area index. However, differences in LAI between plots counteracted the [CO(2) ] impact on E(C) and thus, at least in part, explained the variability of seasonal [CO(2) ] responses between crops and years. As a consequence of lower transpirational canopy water loss, [CO(2) ] enrichment increased plant available soil water content in the course of the season by ca. 15 mm. This was true for all crops and years. Lower transpirational cooling due to a [CO(2) ]-induced reduction of E(C) increased canopy surface and air temperature by up to 2 °C and 0.5 °C, respectively. This is the first study to address effects of FACE on both water fluxes at canopy scale and water status of a European crop rotation.

Canopy CO2 exchange of sugar beet under different CO2 concentrations and nitrogen supply: results from a free-air CO2 enrichment study.

Sugar beet (Beta vulgaris ssp. altissima Döll) was grown in the field under free-air CO(2) enrichment (FACE, 550 ppm) and different nitrogen (N) supply (2001: 126 (N100) and 63 kg.ha(-1) (N50); 2004: 156 (N100) and 75 kg.ha(-1)) during two crop rotations. Canopy CO(2) exchange rates (CCER) were measured during the main growth phase (leaf area index > or =2) using a dynamic chamber system. Canopy CO(2) exchange data were analysed with respect to treatment effects on seasonal means and light use efficiency and light response characteristics. CO(2) enrichment enhanced CCER throughout the season. However, in both years, CCER declined after the second half of August independent of radiation and [CO(2)]. Elevated [CO(2)] strongly stimulated CCER on a seasonal basis, whereas the reduction of CCER caused by low N was below 10% and not significant. There were no effects of N on daily radiation use efficiency of carbon gain calculated from CCER data, but a strong enhancement by CO(2) enrichment. CCER closely tracked diurnal variations in incident photosynthetic photon flux density (PPFD, mumol.m(-2).s(-1)). The relationship between CCER and incident PPFD was curvilinear. In both seasons, initial slopes and maximum rates (CCER(max)) were determined from two 6-day periods using these relationships. The first period was measured after canopy closure (first half of July) and the second in the second half of August. In the first period, elevated [CO(2)] increased the initial slopes. Low N supply affected neither the initial slopes nor their response to elevated [CO(2)] in either period. In contrast to initial slopes, N stress limited the [CO(2)] response of CCER(max) in the first period. In the second period, however, this interaction of [CO(2)] and N on CCER(max) was completely dominated by a general decline of CCER(max) whereas no general decline of the initial slopes occurred in the second period. This response of light response parameters to [CO(2)] and N suggests that, in sugar beet, the decline of CCER in the late season may rely on limiting mechanisms such as photosynthetic acclimation responses to elevated [CO(2)] caused by sink limitations.

Assessing recovery in middle cerebral artery stroke using functional MRI.

PRIMARY OBJECTIVE: To understand the temporal evolution of brain reorganization during recovery from stroke. RESEARCH DESIGN: A patient who suffered left middle cerebral artery stroke 9 months earlier was studied on three occasions, approximately 1 month apart. METHODS AND PROCEDURES: Brain activation was studied using functional Magnetic Resonance Imaging (fMRI). During each session, the patient performed a finger-to-thumb opposition task, which involved one bimanual and two unimanual conditions. Each condition consisted of overt movement of fingers and imagery of the same task. RESULTS: With recovery, greater recruitment was observed of the affected primary motor cortex (M1) and a decrease in activation of the unaffected M1 and supplementary motor area. In addition, the widespread activation of brain areas seen during the initial session changed to a more focused pattern of activation as the patient recovered. Imagery tasks resulted in similar brain activity as overt execution pointing to imagery as a potential tool for rehabilitation.

AlH(3) and Al(2)H(6): magic clusters with unmagical properties.

Enhanced stability, low electron affinity, and high ionization potential are the hallmarks of a "magic" cluster. With an electron affinity of 0.28 eV, ionization potential of 11.43 eV, and a large binding energy, AlH(3) satisfies these criteria. However, unlike other magic clusters that interact only weakly with each other, two AlH(3) clusters bind to each other with an energy of 1.54 eV. The resulting Al(2)H(6), while also a magic cluster in its own right, possesses the most unusual property that the difference between its adiabatic and vertical detachment energy is about 2 eV--the largest of any known cluster. These results, based on density functional theory, are verified experimentally through photodetachment spectroscopy.

Intracast muscle stimulation prevents bone and cartilage deterioration in cast-immobilized rabbits.

Tibial articular cartilage and the knee meniscus from cast-immobilized rabbits whose quadriceps were electrically stimulated for 17 days were compared with those from cast-immobilized rabbits without muscle stimulation. Cartilage from non-stimulated rabbits showed evidence of deep fibrillation and loss of Safranin O metachromasia. Scanning electron microscopy (SEM) showed large areas of cavitation and cartilage erosion. Cartilage from cast-immobilized muscle-stimulated rabbits demonstrated no fibrillation, pitting, or surface erosion at either the light microscopic or SEM levels. Electrical muscle stimulation prevented bone loss by significantly increasing bone turnover rate. These observations suggest that electrical muscle stimulation can prevent bone and cartilage deterioration in short-term cast-immobilized limbs.

Myositis ossificans: report of an unusual case*.

A particularly large bone resulting from myositis ossificans was found in an unusual location, the semimembranosus. Consideration of the radiographic and histological diagnoses are discussed. The importance of being able to diagnose this lesion in young athletes is stressed. J Othrop Sports Phys Ther 1981;2(4):184-186.

Clinical anatomy of the lumbosacral complex.

The clinical anatomy of the lumbosacral region has been presented to show the complexity of spinal pathology. Individual structures are described, but emphasis is placed on understanding the concept of the entire functional unit and how alteration can lead to pain and disability.

The aging intervertebral disk.

This paper outlines the structure of the intervertebral disk and the process by which altered cellular mechanisms lead to deterioration with age. A reference list indicates current trends in research that attempt to explain the changing nature of the intervertebral disk and its role in spinal disease.

The penile bone and anterior process of the rat in scanning electron microscopy.

The penile bone and anterior process were made anorganic for scanning electron microscopy. The mature bone has a basal bulb and a long, cylindrical shaft bevelled at its tip to fit under a matching surface on the anterior process, giving rise to a bevelled 'suture'. A rough, resting, Sharpey-fibre bone surface covers the base and tip of the bone, the dorsal crest along the shaft, and parts of the lateral and ventral surfaces. The penile bone grows by endochondrial ossification at its basal end, but the cartilage cells are randomly disposed and not arranged in columns as in most 'long' bones. The growing bone, at 8 weeks, shows evidence of resorption externally where the base 'waists in' to the shaft: the corresponding endosteal surface within the basal bulb is formative, in accordance with the 'V-principle' of remodelling. It is concluded that the anterior process, penile bone and proximal erectile body (corpus cavernosum) form a firm, tightly fastened, articulating chain, perhaps serving to aid penetration.