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Drum of Shearer undertakes the main function of coal falling and loading, and its performance directly affects the working efficiency of the shearer. Therefore, in order to realize the analysis of the performance of the shearer drum, the MG2 × 55/250-BW shearer drum was the engineered object. Combining the physical and mechanical properties experiment results of coal samples, the coupling model of the drum cutting in complex coal seam was established using discrete element method. The falling-coal characteristics of the spiral drum were studied under different working conditions, and the falling-coal trajectories of the coal and rock particles were fitted. Based on a virtual prototype, the variations of the coal loading rate and lump coal rate with different design parameters were determined by studying the falling-coal effect and loading performance of the drum. Considering the drum performance, multi-objective optimization theory was used to determine the optimal operating and structural parameters. The results indicate that, in the process of drum cutting, the cutting depth has the most significant effect on the coal loading rate, while, the blade spiral angle has the least significant. Moreover, with the increase of the cutting depth of drum and the traction speed, the lump coal rate increases. While, with the increase of the drum rotation speed and the blade spiral angle, the lump coal rate decreases. It is found that when the cutting depth of the drum is 597 mm, the traction speed is 5.4 m/min, the drum rotation speed is 104.8 r/min, and the blade spiral angle is 12° the performance of the drum is optimal. Compared with the falling-coal trajectories before optimization, the displacements of the coal and rock particles ejected along the optimal falling-coal trajectories increase in the coal loading direction. The loading rate and lump coal rate of the drum increase by 6.05% and 12.27%, respectively. The load fluctuation of the drum decreases, and the productivity increases.

Models of reference-dependent preferences show that an individual’s utility depends on the difference between the outcome and a “neutral” reference point. Our paper investigates how distance from reference points affects future performance. We find that round numbers and personal bests motivate runners and that missing the goal by a small amount improves future performance. For those who achieve their goal, future performance suffers slightly. In empirical analysis, we use an extensive panel of marathon data, which contains a past running history for every runner in our sample and allows us to estimate runners’ ability and experience.

In a two-sector model with circulating capital, Laibman (1982) shows that a capital-using and labor-saving technical change in the consumption goods sector lowers the rate of profit under the assumption of constant rate of exploitation. This paper generalizes his finding in a two-department multi-sector model that considers the capital advanced. JEL Classification: B51, C67

Light can impact human health via the visual and non-visual systems originating in the retina of the eye or as optical radiation falling on eye or skin. This paper provides a summary of what is known about these impacts. Topics covered include aspects of lighting likely to cause eyestrain and headaches; increase the risk of falls; induce circadian disruption; enhance sleep; mitigate Alzheimer’s disease and depression; produce tissue damage; alleviate diseases through phototherapy and inactivate viruses through germicidal irradiation. It is concluded that human health is undoubtedly influenced by lighting, but there are four conditions that should be attached to such a simple assertion. First, the impact of lighting on human health can be either positive or negative. Second, human health is affected by many factors other than lighting. Third, the severity of the effects of light exposure can vary widely from the short-lived and trivial to the long-term and fatal. Fourth, the same lighting conditions can have very different health impacts for different individuals depending on their age and medical status. Taken together, these conditions imply that care is required when judging the veracity and relevance of broad assertions about the benefits of lighting for human health.

An experiment of falling wheels was performed in this study along with full-field tests, for a type of subway train on four subway lines. The results confirmed that 40–80 Hz vibration signals on the ground and train are caused by the wheel–rail P2 force. Vehicle–track-coupled dynamics models were created where the single-layer elastic support model, double-layer elastic support model and floating slab track model were considered. The results were validated by available experimental data and three types of theoretical models: Jenkins, Winkler and double-beam model. This shows that the amplitude of the P2 force increases with larger suspended rail joint angle, higher train speed, heavy unsuspended mass and stronger fastener stiffness. Besides, both fastener damping and the vertical stiffness of primary suspension enabled control of the amplitude of the P2 force in a limited interval. Supporting stiffness of track and unsprung mass played a key role in the frequency of the P2 force. However, the vertical stiffness of the primary suspension had a reduced effect on the frequency of P2 force as compared with the supporting stiffness. Thus, for an effective change to the supporting stiffness, the fastener stiffness could be changed accordingly.

Objective: Benign paroxysmal positional vertigo (BPPV) is characterized by recurrent attacks of vertigo caused by head movements. It occurs as a result of otoconia falling into the semicircular canal. Calcium and 25 hydroxyvitamin D [25(OH)D] metabolism in the inner ear play an important role in otoconia formation and degeneration. Our aim in this study was to investigate the relationship between 25(OH)D levels and BPPV. Methods: This retrospective, case–controlled study included 52 patients with posterior canal BPPV and 52 controls aged 18 to 80 years. Age, sex, serum calcium, corrected calcium, and 25(OH)D levels of the BPPV and control group were compared. Results: Twenty-three of the patients were male (44.2%) and 29 were female (55.8%). The average age was 55.6 years. The 25(OH)D level was 15.3 ng/mL in the BPPV group and 20.2 ng/mL in controls. There was no significant difference in 25(OH)D and albumin-corrected calcium values ( P = .394; P = .084, respectively). In 80.7% of the BPPV group and 61.5% of the controls, 25(OH)D levels were 20 ng/mL and below. 25 hydroxyvitamin D deficiency was found statistically significantly more frequently in patients with BPPV ( P = .030). Conclusion: In our study, serum 25(OH)D levels were found to be lower in patients with BPPV, and the rate of vitamin D deficiency was higher in these patients. Based on these results, it is recommended to examine the 25(OH)D levels of patients with BPPV at the time of diagnosis.

Objective: To assess the effect of a domiciliary program of oculomotor and gaze stability exercises on the incidence of falls and risk of fall in stroke survivors. Design: Two-arm, non-blinded parallel randomized controlled trial. Subjects: Stroke survivors older than 60 years, with positive Romberg test and autonomous gait after the stroke. Setting: Physiotherapy outpatient clinic of a tertiary care hospital. Interventions: Every participant accomplished the current rehabilitation program; the intervention group was randomly allocated into an additional three weeks intervention with a domiciliary program of oculomotor and gaze stability exercises. Main measures: Primary outcome was the incidence of falls through the three weeks after the intervention started; in addition, the variation of the estimated risk for falling assessed by both Berg Balance Scale (four points) and Timed Up and Go Test (four seconds) was the secondary outcome. Results: 79 patients were recruited and 68 completed the protocol (control group 35; intervention group 33). During the follow up, falls were registered in 4/35 participants in the control group and no event occurred in the intervention group ( P = 0.064). The estimated risk for falling decreased in 11/35 control group participants and in 28/33 intervention group participants (RR 0.37; 95%CI 0.22–0.62; P < 0.001). Conclusion: After three weeks of a domiciliary program of oculomotor and gaze stability exercises, the estimated risk of falling significantly diminished and no falls occurred among the intervention group. These findings encourage further exploration of this promising intervention. Trial Registration: ClinicalTrials.gov Identifier: NCT02280980.

At some point between the writing of 1 and 2 Corinthians, there has been a significant falling out between Paul and some in the Corinthian Christian community. As a result, Paul leaves Corinth with the intention of returning to deal with it at a later date. He then changes his mind, instead writing a letter known to us as the ‘painful letter’. This letter was effective in bringing about reconciliation, but questions still lingered as to why he did not return in person, instead staying away and sending a harsh letter. The section of letter found in 2 Cor. 1.1–2.13 and 7.5-16 seeks to address these concerns. It is the contention of this article, however, that Paul does more than simply recount recent events. Instead, he reframes his behaviour as something akin to voluntary exile. By comparing the letter to exilic writings from Cicero, Ovid, Seneca and Demosthenes, it will be proposed that 1.1–2.13 and 7.5-16 resembles a letter from exile.

Irrational fear of falling is defined by the high degree of psychological fear a person has of falling when in reality, that person is at low physiological risk of falling. It is a significant problem in older people and may manifest from previous falls or fall-related depression and/or anxiety. If untreated, it may lead to increased falling, decreased mobility, social isolation, and decreased participation in daily activities. A mixed-methods, home-based, 8-week, physio-feedback/exercise program was developed for an older adult to help mitigate her irrational fear of falling. In this pilot case study, the quantitative independent variables of fear of falling, static balance, dynamic balance, fall risk factors, and fall risk appraisal were assessed pre- and post-intervention. A qualitative semi-structured interview was also conducted to help assess the participant’s reaction to the intervention. Data from quantitative, qualitative, and integrated viewpoints converged to indicate the intervention improved fear of falling, shifted the participant’s perception from irrational to rational fall risk appraisal and increased participation in daily activities.

Effects of different age groups and different external loading distribution on lower extremity muscle activation during obstacle crossing tasks were tested in this study. Four young participants and five healthy senior participants performed different walking tasks at their own speed carrying multiple different weights while their lower extremity muscle activation patterns were recorded and compared. Older adults showed significantly increased muscle activation patterns in obstacle negotiation. Furthermore, participants showed altered lower extremity muscle activation patterns with different load distribution.

My argument follows geographer Gunnar Olsson when he asks, “What is geography if it is not the drawing and interpreting of a line? And what is the drawing of a line if it is not also the creation of new objects?” Using Thomas Pynchon’s 1997 novel Mason & Dixon ( MD), about the drawing of the Mason-Dixon line, I explore how the mapmaker’s productive power is never merely reflective, but generative too, constructing a world as much as representing one. I question the consequent relation between “above and below,” drawing on Farinelli’s insight that critique of such constructions must recognize an antagonistic humor in the production of maps and territories. Pynchon’s novel, I argue, is exemplary in the wit with which it pits the anomalous, strange, and contingent phenomena of the below against the homogenizing, categorizing power of above. His approach helps us understand the dark heart of Enlightenment cartography and society.

Background. Persons with stroke (PwS) are at increased risk of falls, especially toward the paretic side, increasing the probability of a hip fracture. The ability to recover from unexpected loss of balance is a critical factor in fall prevention. Objectives. We aimed to compare reactive balance capacity and step kinematics between PwS and healthy controls. Methods. Thirty subacute PwS and 15 healthy controls were exposed to forward, backward, right, and left unannounced surface translations in 6 increasing intensities while standing. Single step threshold, multiple step threshold, and fall threshold (ie, perturbation intensity leading to a fall into harness system) were recorded as well as reactive step initiation time, step length, and step velocity. Results. Twenty-five PwS fell into harness system during the experiment while healthy controls did not fall. Fourteen out of 31 falls occurred in response to surface translations toward the nonparetic side, that is, falling toward the paretic side. Compared with healthy controls, PwS demonstrated significantly lower fall threshold and multiple step threshold in response to forward, backward, and lateral surface translations. Impairments were more pronounced in response to forward surface translation and toward the nonparetic side (ie, loss of balance toward the paretic side). A trend toward significant shorter step length in response to lateral surface translations was found in PwS compared with healthy controls. Conclusions. Findings highlight the importance of assessing reactive balance capacity in response to perturbations in different directions and intensities in addition to the routine assessment in PwS.

Bio-inspired robotic designs introducing and benefiting from morphological aspects present in animals allowed the generation of fast, robust, and energy-efficient locomotion. We used engineering tools and interdisciplinary knowledge transferred from biology to build low-cost robots, able to achieve a certain level of versatility. Serval, a compliant quadruped robot with actuated spine and high range of motion in all joints, was developed to address the question of what mechatronic complexity is needed to achieve rich motion skills. In our experiments, the robot presented a high level of versatility (number of skills) at medium speed, with a minimal control effort and, in this article, no usage of its spine. Implementing a basic kinematics-duplication from dogs, we found strengths to emphasize, weaknesses to correct, and made Serval ready for future attempts to achieve more agile locomotion. In particular, we investigated the following skills: walk, trot, gallop, bound (crouched), sidestep, turn with a radius, ascend slopes including flat ground transition, perform single and double step-downs, fall, trot over bumpy terrain, lie/sit down, and stand up.

Effective maintenance of a concrete pavement requires precise evaluation of the load transfer efficiency (LTE) at the transverse joint, which is simply calculated from the falling weight deflectometer (FWD) deflections at the loaded and unloaded slabs. In this study, the FWD deflections were simulated with the randomly generated elastic moduli of the pavement layers using the three dimensional finite element method considering the degradation process at a joint, which was categorized into five stages, from completely sound, to having broken dowels and a void underneath the joint. A database of FWD deflections, layer elastic moduli and the associated stage was created from the simulation results. The layer moduli were identified from the measured FWD deflections at a joint by searching the closest calculated FWD deflections to those measured from the database. The results of the analysis not only provide the layer moduli, but also the degradation stage of the joint to help engineers determine the appropriate rehabilitation measures. The method was validated on a 16 year old concrete pavement, on which the FWD measurements were performed three times: just before opening to traffic, after 9 years and 16 years of service. The identified layer moduli were not changed after 16 years of service, and some joints degraded owing to dowel corrosion, broken dowels and the existence of voids underneath the joints. The developed method is able to show the entire picture of the state of the joints in a section and also provide information on which parts of a particular joint have deteriorated.

In this study, a two-dimensional computational model describing the rise and development of thin liquid water film on a rotating drum is presented. The liquid water flow is predicted by solving the Navier–Stoke equation using computational fluid dynamics neglecting the end effects of the rotating drum side wall along width. The liquid film on a half-submerged rotating drum was modeled by volume of fluid to determine the thickness and quality of the liquid film on a rotating drum. Computational results show that the liquid film on the rising side is smooth, whereas the film on the plunging point is complex. For a 300 r/min of 75 mm rotating drum, it takes ∼300 ms to develop the film from the rising point to fall to the plunging point. Air is entrained in plunging side by the falling film from the rising side.

Case summary A 1-year-old spayed female domestic shorthair cat presented for evaluation of a non-weight bearing right pelvic limb lameness after falling from a 4 m height. On orthopedic examination there was substantial swelling and pain on manipulation of the right pes. Radiographs were obtained under sedation, and these revealed dorsoproximal luxations of the third, fourth and fifth metatarsophalangeal joints, and lateral rotation of the second digit. Closed manual reduction under sedation was unsuccessful and open reduction under general anesthesia was therefore performed. Combined transarticular pinning and external skeletal fixation were performed to maintain reduction of the third and fourth digits. Marked postoperative swelling of the distal pes and internal rotation of the third and fourth digits were noted within 24 h of surgery. Three weeks postoperatively, the cat had a persistent weight bearing right pelvic limb lameness and minor pin tract inflammation. All implants were removed and the limb was splinted for 1 week. Internal rotation and pin tract inflammation had resolved at the time of splint removal, and the lameness resolved within 6 weeks of surgery. The cat was not lame, but radiographs revealed mild-to-moderate degenerative osteoarthrosis when the cat was evaluated 6 months after surgery. Relevance and novel information There are limited reports describing metatarsophalangeal luxations in cats. Although several surgical techniques have been advocated, specific outcomes in clinical cases have not been reported. This report describes the clinical application and outcome of combined transarticular pinning and external skeletal fixation for the management of multiple metatarsophalangeal luxations in a cat.

A new falling weight test method based on the direct impact on the rail was studied and a backcalculation model was developed to estimate the moduli of the railway substructure layers. The model is three-dimensional, dynamic, and considers the superstructures. After the preliminary studies on the impact system and measurement setup on a test track, a case study was performed on a railway station track. The data were recorded using a series of linear variable differential transformers, geophones, and accelerometers during the proposed falling weight test on the rail. To establish the soil profile and better understanding of the site, geotechnical and geophysical investigation of the soil was done using in situ and conventional laboratory tests. The studies show that the rail falling weight test is feasible and leads to reasonable results. Verification of the backcalculation model with the ABAQUS finite element simulation and comparison of the backcalculated moduli with the results of site investigations show that the function of the backcalculation model is satisfactory.

The four primary factors affecting the likelihood of slipping and falling include walking surface material and finish, footwear sole design and condition, contaminants present at the interface between the floor and shoe sole, and human factors issues such as gait dynamics and expectancy. Perhaps the least studied of these factors is footwear. Footwear sole materials vary widely in their composition, tread pattern, and hard-ness. The purpose of this study was to assess the slip resistance of a variety of common shoe sole materials on selected floor surfaces under wet and dry conditions. Five shoe sole materials were tested on six floor surfaces. The results showed a wide variance in slip resistance among popular shoe sole materials. Moreo-ver, some shoe sole materials were substantially more susceptible to reductions in slip resistance when the floor surface was contaminated with water.

It is seen that previous research on falling vibration of landing gear only provides work–stroke diagram and damping force value. Nevertheless, the change process of buffering medium at a micro-level is yet to be analyzed. The velocity, pressure, and their change over time of fluid particle are rarely researched in reality. To improve the intuitive, concreteness, and accuracy of the falling vibration analysis, this paper uses theoretical calculation and simulation to analyze oil damping energy loss of shock absorber. On the basis of theoretical calculation, the paper provides a feasible solution for calculating oil damping energy loss in the drop test of landing gear. Based on the classical fluid mechanics, the research builds a series-parallel model for calculating oil damping coefficient, and the oil damping energy loss values are calculated. To the flow passage type with one inlet and two outlets, the best solution of volume flow rate weighting of two outlets is determined. With regard to simulation, ANSYS FLUENT is used to show the dynamic flow process of oil in damping orifice. Damping energy loss values are calculated by total pressure difference. By comparison, the results of the theoretical calculation, the simulation, and the drop test achieve a good consistency.

This article presents a simulation of a full-scale falling protection net using three-dimensional distinct element method. First, an application of distinct element method utilized cylinder rigid body element for collision response analysis of a flexible structure that has a long and slender shape similar to wire rope. Second, contact spring normally obtain contact force between the cylindrical element and spherical element in the case of distinct element method. However, connect spring that expresses axial stiffness like tension or compression and bending stiffness of the flexible structure was indicated as a fresh approach of the analysis method. Third, it is suggested to simulate large deformation program using connect spring of three-dimensional distinct element method and examine the application of reproducibility to analyze a full-scale falling protection net. Finally, the analysis result evaluated the performance of falling protection net using distinct element method which utilized connect spring and cylindrical model.

Background. Navigating obstacles whilst walking might be associated with poorer balance and a higher risk of falling in individuals with symptomatic Huntington’s disease (symp-HD). However, this issue has not been investigated within the literature. Objective. A unique obstacle navigation experiment was designed to examine adaptive gait patterns in order to identify spatiotemporal gait characteristics that might be associated with poorer balance and a higher risk of falling in symp-HD. Method. Sixteen diagnosed symp-HD participants and 16 age- and sex-matched healthy controls were included. Gait was examined in 3 experimental conditions: baseline walking, walking while navigating around 1 obstacle, and walking while navigating around 2 obstacles. Navigation around obstacle walks was divided into three step phases (approach, navigation, recovery). Group differences in gait variables were analyzed at baseline and during walking for each obstacle condition respectively. Gait variables were also correlated with the Berg Balance Scale (BBS) and Timed Up and Go (TUG) test. Results. Symp-HD participants, compared with controls, performed significantly poorer on most gait variables during baseline walking. Symp-HD participants significantly decreased their step-length while navigating around 1 obstacle, and increased their step-time while navigating around 1 and 2 obstacles. There were no significant group differences in step-width. Variables associated with navigating around obstacles correlated significantly with BBS and TUG clinical tools, which have been associated in the literature with an increased risk of falling in symp-HD. Conclusion. These findings could aid clinicians in better managing risk of falls in people with Huntington’s disease through targeted and effective strategies.

Palmer, Gardner, and Wickens studied aesthetic preferences for pictures of single objects and found a strong inward bias: Right-facing objects were preferred left-of-center and left-facing objects right-of-center. They found no effect of object motion (people and cars showed the same inward bias as chairs and teapots), but the objects were not depicted as moving. Here we measured analogous inward biases with objects depicted as moving with an implied direction and speed by having participants drag-and-drop target objects into the most aesthetically pleasing position. In Experiment 1, human figures were shown diving or falling while moving forward or backward. Aesthetic biases were evident for both inward-facing and inward-moving figures, but the motion-based bias dominated so strongly that backward divers or fallers were preferred moving inward but facing outward. Experiment 2 investigated implied speed effects using images of humans, horses, and cars moving at different speeds (e.g., standing, walking, trotting, and galloping horses). Inward motion or facing biases were again present, and differences in their magnitude due to speed were evident. Unexpectedly, faster moving objects were generally preferred closer to frame center than slower moving objects. These results are discussed in terms of the combined effects of prospective, future-oriented biases, and retrospective, past-oriented biases.

Extending work by Montare, visual simple reaction time, choice reaction time, discriminative reaction time, and overall reaction time scores obtained from college students by the simplest chronoscope (a falling meterstick) method were significantly faster as well as significantly less variable than scores of the same individuals from electromechanical reaction timers (machine method). Results supported the existence of dual reaction time systems: an ancient primary reaction time system theoretically activating the V5 parietal area of the dorsal visual stream that evolved to process significantly faster sensory-motor reactions to sudden stimulations arising from environmental objects in motion, and a secondary reaction time system theoretically activating the V4 temporal area of the ventral visual stream that subsequently evolved to process significantly slower sensory-perceptual-motor reactions to sudden stimulations arising from motionless colored objects.

In the past, robots can only do simple walking, but now robots can perform complex actions such as running, attacking and automatically standing up after falling to the ground. The humanoid robot c...

We report three cases of serious combined rectovaginal injuries, from a forceful waterjet after falling backwards with legs abducted from the back of a jet ski. In all cases, the passengers were unaware of this risk and did not wear protective clothing. In one case, massive fecal spillage to the lower and upper retropritoneum led to death within 33 h, despite laparotomy, colostomy and retroperitoneal lavage. We recommend increasing the awareness of jet ski drivers and passengers to this particular danger, using protective suits and enforcement of adequate boating regulation by the local authorities. Hospitals located near recreational boating amenities must maintain higher alertness and capability of dealing with such particular serious and complicated injuries.

Gianantonio Tadini (1754–1830) is the little known protagonist in an important experiment carried out in Bergamo between 1794 and 1795. Based on the measurement of the deviation of a falling body, the experiment owes much to the one that was conducted by Giambattista Guglielmini (1760–1817) in Bologna in 1791, which aimed at demonstrating Earth’s rotation. Tadini’s experimental work represents the most successful attempt carried out before the 19th century, and it led to the first correct formulation of deviation’s measurement. In spite of this, it is not well represented in the general literature on the history of experiments intended to show diurnal Earth’s motion.1 The discovery of Tadini’s diary of experiments as well as some notes and a part of his correspondence – preserved as manuscripts in the Angelo Mai municipal library in Bergamo – allows us now to reconstruct the history of Tadini’s experiment and of his reasoning about Guglielmini’s work. In this paper, I describe the genesis and the development of Tadini’s experiment, clarify the role played by the different personalities involved and set these trials against the background of the widest history of proofs on diurnal Earth’s rotation carried out in Europe in those years.

Background: Minimum toe clearance is a critical gait event because it coincides with peak forward velocity of the swing foot, and thus, there is an increased risk of tripping and falling. Trans-tibial amputees have increased risk of tripping compared to able-bodied individuals. Assessment of toe clearance during gait is thus clinically relevant. In able-bodied gait, minimum toe clearance increases with faster walking speeds, and it is widely reported that there is synchronicity between when peak swing-foot velocity and minimum toe clearance occur. There are no such studies involving lower-limb amputees. Objectives: To determine the effects of walking speed on minimum toe clearance and on the temporal relationship between clearance and peak swing-foot velocity in unilateral trans-tibial amputees. Study design: Cross-sectional. Methods: A total of 10 trans-tibial participants walked at slow, customary and fast speeds. Minimum toe clearance and the timings of minimum toe clearance and peak swing-foot velocity were determined and compared between intact and prosthetic sides. Results: Minimum toe clearance was reduced on the prosthetic side and, unlike on the intact side, did not increase with walking speed increase. Peak swing-foot velocity consistently occurred (~0.014 s) after point of minimum toe clearance on both limbs across all walking speeds, but there was no significant difference in the toe–ground clearance between the two events. Conclusion: The absence of speed related increases in minimum toe clearance on the prosthetic side suggests that speed related modulation of toe clearance for an intact limb typically occurs at the swing-limb ankle. The temporal consistency between peak foot velocity and minimum toe clearance on each limb suggests that swing-phase inter-segmental coordination is unaffected by trans-tibial amputation. Clinical relevance The lack of increase in minimum toe clearance on the prosthetic side at higher walking speeds may potentially increase risk of tripping. Findings indicate that determining the instant of peak swing-foot velocity will also consistently identify when/where minimum toe clearance occurs.

This paper argues that Marx’s law of the falling rate of profit applies to the problematic of choice of technique in the context of accumulation of capital, and not to the problematic of choice of technique in the context of technological change or new innovation as such. In this context, Marx’s “the law itself” is correct. It is, however, true that Marx does confuse the two contexts at times; but here he seems to be following in the footsteps of Ricardo, who had also made an identical mistake.

When performing forensic human factors analyses it is imperative to carefully evaluate plaintiff and defense claims to determine if they are consistent with theoretical research and science. This case study concerns a fall from airstairs by a woman who was disembarking an airplane. At face value, the circumstances seemed valid enough that the airline chose to settle with the plaintiff before any kind of expert evaluation was performed. However, when the plane manufacturer was countersued, it chose to hire a human factors expert. A human factors expert analysis revealed that the plaintiff’s description of the incident was inconsistent with the evidence. Also considered were safety factors of airstair and airplane design. This case highlights the importance of evaluating witness descriptions of an incident as part of a forensic human factors analysis.

The history and development of our understanding of sea level changes is reviewed. Sea level research is multi-fascetted and calls for integrated studies of a large number of parameters. Well established records indicate a post-LIA (1850–1950) sea level rise of 11 cm. During the same period of time, the Earth's rate of rotation experienced a slowing down (deceleration) equivalent to a sea level rise of about 10 cm. Sea level changes during the last 40–50 years are subjected to major controversies. The methodology applied and the views claimed by the IPCC are challenged. For the last 40–50 years strong observational facts indicate virtually stable sea level conditions. The Earth's rate of rotation records a mean acceleration from 1972 to 2012, contradicting all claims of a rapid global sea level rise, and instead suggests stable, to slightly falling, sea levels. Best estimates for future sea level changes up to the year 2100 are in the range of +5 cm ±15 cm.

The frictional performance of the brake material used in mine hoisters varies abnormally under some extreme braking conditions. Its friction coefficient runs the danger of falling suddenly in such a braking. Based on the catastrophe theories and the energy transforming ideas, this article established a cusp catastrophe model to describe and predict the friction catastrophe behaviors of the brake material in some continuous repeated brakings of mine hoisters. The predictive capability of the model was verified by some braking experiments. It is shown that the catastrophe phenomena of the friction catastrophe in braking can be described by the catastrophe theories as a cusp catastrophe. The friction coefficient can be taken as its state variable. The initial braking velocity and braking frequency can be taken into account for one control variable while another control variable may contain the braking pressure and braking time. Moreover, the friction catastrophe of the brake material has a critical braking state. The cusp model built in this article can properly predict its critical braking frequency. However, in the present state, the exact time that the friction catastrophe occurs in a critical braking cannot be accurately located.

Introduction Maintaining balance while walking is of utmost importance for individuals with visual impairments because deficits in dynamic balance have been associated with a high risk of falling. Thus, the primary aim of the study presented here was to determine whether balance training effects the dynamic balance of children with visual impairments. Methods The study included 19 children with visual impairments (aged 8 to 14) from the school for students with visual impairments in Isfahan, Iran, who were randomly assigned to a balance-training (n = 9) or control (n = 10) group. The balance-training group was required to participate in an eight-week balance-training program, while the control group did not participate in any organized balance-training program. The Modified Bass Test of Dynamic Balance was used to measure the dynamic balance of the participants. Both groups performed a pretest prior to the experimental period and performed a posttest immediately after the experimental period. Results The scores on the pretest showed no significant difference between the balance-training group and the control group. However, after the balance-training group completed the balance-training program, a between-group difference was found in the participants’ task scores, t (18) = 4.095, p < .05. Discussion The findings indicate that involvement in a balance-training program will significantly improve the dynamic balance of individuals with visual impairments relative to a control group. Implications for practitioners The study showed that if instructors require individuals with visual impairments to perform balance-improving exercises, the result can be an outstanding improvement in their dynamic balance. With improved balance, individuals with visual impairments may encounter fewer falls and experience a healthier lifestyle.

A via ferrata (Italian for ‘iron road’) is a climbing route with fixed iron climbing aids in steep, rocky mountain terrain. Climbers attach themselves to the climbing aids with a via ferrata set (a certain safety equipment designed for vie ferrate) and a harness. In case of a fall the via ferrata set should prevent injuries by reducing the deceleration of the falling body. Different standards exist worldwide for the deceleration and forces acting in the case of a fall; the European standard is evaluated for 80 kg heavy individuals. In this paper the acceleration and force differences for different climber weights – especially lightweight climbers – are evaluated. For this purpose four different NCAP frontal crash dummies representing humans of different weights and ages (3 y, 15 kg; 10 y, 34 kg; female adult, 48 kg; male adult, 77 kg) were dropped from a height of 5 m into different via ferrata sets. During a fall accelerations and braking forces were measured, A/D converted with a frequency of 1024 Hz and 1000 Hz, respectively and recorded on a PC. Additionally synchronous video data were recorded with two cameras (240 fps, 448 [Formula: see text] 336 px). A total of eight via ferrata sets of two different types were evaluated: (1) modern web-based sets where a webbing is ripped apart and absorbs energy (tearing energy absorbers), and (2) cheaper rope-braking systems which absorb energy by friction (friction energy absorbers). The results show that the maximum braking forces allowed in the European standard were exceeded in several cases. Maximum braking distances were not used to full capacity in any of the trials. Thus, falls could have caused injuries especially for lightweight climbers. Hence, according to the gathered data a minimum weight limit for via ferrata sets should be established. European standards should be adopted in consideration of the presented results of this study.

Passenger falls on escalators are one of the major causes of accidents. Falls can either be passenger caused or escalator caused. Unplanned stops of escalators can cause passenger falls and consequential injury in the form of cuts, bruises, finger entrapment and, in certain cases, crushing leading to suffocation. In order to better understand the kinematics of passenger falls on escalators, MATLAB-based software has been developed. It simulates the effect of an acceleration signal on a rectangular block. The most important parameter of the rectangular solid block is the center of gravity ratio, which is defined relative to the axis around which the fall can take place. The model is then practically verified by subjecting an actual wooden rectangular block of a specific center of gravity ratio to an acceleration signal and taking a video of the fall. The acceleration signal is measured and fed into the model. The video is analyzed frame by frame in order to use time-lapse photography to compare the falling block with the output of the model. Good agreement has been achieved. Data on the human body is analyzed in order to arrive at an appropriate value of the center of gravity ratio for the human body. This value is further adjusted to account for variability in the human body, and expected human behavior, up to a value of 10. This result is then used to arrive at a limit on the maximum value of acceleration form the escalator braking system in order to prevent escalator-initiated passenger falls. Applying knowledge of the variability of the expected maximum acceleration from successive escalator stops is then applied to arrive at the final value of 1.16 m·s–2 as the recommended value to be used as a design and acceptance value for escalator braking system performance in order to prevent passenger falls.

Data on 251 quarters of the U.S. economy show that recessions are preceded by declines in profits. Profits stop growing and start falling four or five quarters before a recession. They strongly recover immediately after the recession. Since investment is to a large extent determined by profitability and investment is a major component of demand, the fall in profits leading to a fall in investment, in turn leading to a fall in demand, seems to be a basic mechanism in the causation of recessions. JEL codes: E01, E11, E32

Balance or postural control is a necessary component of activities of daily living and sport. Static balance involves feedback from the somatosensory, visual, and vestibular systems to achieve steadiness.16,27 Instrumented testing devices attempt to objectively measure balance and are becoming the gold standard of balance testing.24 Common variables include sway area and sway velocity using force plates. The NeuroCom Smart Balance System (NeuroCom International, Inc, Clackamas, Oregon) uses the Sensory Organization Test to measure vertical ground reaction forces produced from the body’s center of gravity moving around a fixed base of support. The test systematically disrupts the sensory selection process by altering available somatosensory and/or visual information while measuring the ability to minimize postural sway.17 An equilibrium score can be calculated on the basis of a person’s limit of stability. Clinicians do not often have access to instrumented balance testing devices. The Balance Error Scoring System (BESS) consists of 3 stances: double-leg stance (hands on the hips and feet together), single-leg stance (standing on the nondominant leg with hands on hips), and a tandem stance (nondominant foot behind the dominant foot) in a heel-to-toe fashion (Figure 1). The stances are performed on a firm surface and on a foam surface with the eyes closed, with errors counted during each 20-second trial. An error is defined as opening eyes, lifting hands off hips, stepping, stumbling or falling out of position, lifting forefoot or heel, abducting the hip by more than 30°, or failing to return to the test position in more than 5 seconds. Figure 1. Stances used in Balance Error Scoring System: A, double-leg stance; B, single-leg stance (standing on the nondominant limb); C, tandem stance; D, double-leg stance with foam; E, single leg on foam; F, tandem stance on foam.

Background We welcomed the innovative arthroscopic stabilization of the acromioclavicular joint dislocations with the Tightrope as it seemed promising regarding results and rehabilitation however our results were not satisfactory. Materials and Methods We clinically and radiographically reviewed the first thirty one consecutive patients treated with this method and analysed their scores in search of correlations between results and patient, injury or surgery factors. Results We had 19% failure rate that was not statistically correlated with any factors. Conclusion We believe the Tightrope alone is not adequate to stabilize the acromioclavicular joint as it does not address the acromioclavicular ligament and the instability at the anteroposterior plane.

This paper presents results from a study of how speed varies among vehicle categories under variable winter conditions and how incline affects traffic flow. The study was divided into two parts. The first part was a case study with observations of traffic behavior influenced by weather events. The case study formed the basis for hypotheses about how winter conditions could influence speed. The second part of the study tested some of these hypotheses through information about traffic, climate, friction, and winter maintenance activities over 2 to 4 years. The study found that speeds in all vehicle categories decreased when the coefficient of friction fell below 0.30. If snow was falling as well, the speed decreased further. For trucks, it appeared that snow, in conjunction with a corresponding reduction in visibility and poor driving conditions, reduced speed substantially. On a straight stretch with no incline, there was less difference in speed levels among vehicle categories, and load seemed to have little or no effect at all on speed. Concern arose that the speed level did not decrease more when the coefficient of friction fell below 0.3. This finding indicated that drivers of both passenger cars and trucks drove with elevated risk when the friction was reduced. When it was snowing, it seemed that drivers adapted better to driving conditions.

Older adults over age 65 are susceptible to loss of balance for a variety of reasons including drops in blood pressure with standing (orthostatic hypotension [OH]; Gray-Miceli, Ratcliffe, Thomasson, Quigley, Li & Craelius, 2016). OH is a treatable condition, and cause of falls if detected. Nearly 50% of the 1.43 million older adults in long-term care experience falls (National Center for Injury Prevention and Control, 2017). Falls often occur among older adults in long term care during periods of transitioning, where older adults are susceptible to loss of balance and increased risk to fall. As found in our prior work, older adults with OH may not always experience classic dizziness symptoms that may accompany OH (Gray-Miceli, Ratcliffe, Liu, Wantland & Johnson, 2012; Gray). To better understand this phenomenon, our project adapted a cellphone as an inertial measurement unit attached to the person’s center of mass to determine body sway. The objective of this pilot study was to determine if a relationship was observable during the sit to stand maneuver (StS) while older adults wore a Smartphone measuring three dimensions of motion among older adults who had evidenced of symptoms or OH. A sample of four older adults from a rehabilitation facility who were 65 years of age, receiving physical therapy at the time of testing, were cognitively intact, able to perform the StS maneuver and had no active cancer, fractures or serious injuries were recruited and enrolled. Oh determinations, pulse rate and symptoms of dizziness were elicited during a 30 second StS maneuver. In Patient A and Patient B we present the Z-axis and X-axis of front acceleration and patterns of motion side by side for case comparison while highlighting clinical findings. In Patient B, a greater degree of sway at the start of the StS maneuver is noted. Patient B’s blood pressure also dropped 33 mmHg and there were symptoms of dizziness. Drops in mean arterial blood pressure were greater among those with symptomatic OH. Limitations of this pilot include noise, selection of filters and time stamping of the data. Project aims are to help clinicians prevent falls by further assessing symptoms among elders who suffer from LOB and OH.

This study aims to understand the effects of climbing style (hands on rungs vs. hands on rails), ladder pitch and bank, and carrying objects on hand and foot forces. An instrumented ladder was constructed to OSHA 1910.27 Fixed Ladder Standards. Hand and foot forces were recorded for six male and six female subjects as they ascended and descended the ladder. Although significant inter and intra subject climbing styles were observed for rung and rail climbing, it is still possible to draw important conclusions about the effects of climbing style, ladder pitch and bank, and carrying objects up and down ladders. Most of the work to ascend and descend the ladder is performed with the lower limbs. The hands must constantly exert force to prevent falling from a vertical ladder. Less hand force was exerted on the rails than on the rungs. Hand placement during rung climbing is constrained by rung spacing, while hand placement during rail climbing is determined by climber preference. It can be shown that required hand force is related to vertical hand placement and body center of mass position. Even though less resultant hand force was exerted during rail climb, the lateral component of hand force was greater for rail climbing than for rung climbing. Lateral hand forces may tend to destabilize the climber from the center of the ladder. Tilting the ladder forward reduces hand forces, which is consistent with the biomechanics of climbing and with previous studies. Tilting the ladder laterally did not significantly affect peak hand and foot forces, but it did affect the observed load/unload cycle time for hand and foot climbing movements.

Integrated marketing communications isn't new, but it's gaining momentum as power shifts from the marketer to the consumer and as marketers recognize the power and efficiency of taking a holistic approach to engaging consumers… For too long, marketing functions have been vertically organized by media type. This siloed approach is mirrored on the agency side, with rewards based on discipline-specific P&L models. These silos must be torn down…The client-side strategic integrator must involve and lead a team of colleagues who have the responsibility, vision, understanding and commitment to engage in a media-agnostic planning process. And this team of enlightened marketers must be willing to let strategic goals-not historic patterns- drive budget allocations. –Bob Liodice, Advertising Age, June 9, 2008

Perception of self-tilt is affected by shearing force acting on the otolith organs in the ears, by pressure acting on the tactile receptors in the skin, and by visual pattern falling on the retinae. We examined how the vestibular, somatosensory, and visual inputs interact in judging self-tilt in roll. Each of fourteen observers, sitting in a chair and gazing at a rotation pattern in the frontal plane, was tilted to various angles and verbally judged to what extent his/her body was tilted. The independent variables examined were body tilt (0° to ±108°), and the rate (7.5° s−1, 15° s−1, and 30° s−1) and direction (CW and CCW) of the visual rotating pattern. We found that (i) the sensory scale for self-tilt is represented by a third-order polynomial lacking the quadratic component, (ii) perceived self-tilt for the CW (or CCW) rotation of the visual pattern is displaced CCW (or CW), (iii) the linear and cubic components of the equation increase with an increase in the rate of rotation of the visual pattern, and (iv) if the body is tilted in concord with the direction of vection, the velocity of visual pattern is effective, but when the body is tilted in conflict with the direction of vection, it is less effective. These findings are interpreted in terms of vestibular and somatosensory suppressions exerted on the effects of vection.

The information on the variation of ligament strains over time after rear impact has been seldom investigated. In the current study, a detailed three-dimensional C0—C7 finite element model of the whole head—neck complex developed previously was modified to include T1 vertebra. Rear impact of half sine-pulses with peak values of 3.5 g, 5 g, 6.5 g and 8 g respectively were applied to the inferior surface of the T1 vertebral body to validate the simulated variations of the intervertebral segmental rotations and to investigate the ligament tensions of the cervical spine under different levels of accelerations. The simulated kinematics of the head—neck complex showed relatively good agreement with the experimental data with most of the predicted peak values falling within one standard deviation of the experimental data. Under rear impact, the whole C0—T1 structure formed an S-shaped curvature with flexion at the upper levels and extension at the lower levels at early stage after impact, during which the lower cervical levels might experience hyperextensions. The predicted high resultant strain of the capsular ligaments, even at low impact acceleration compared with other ligament groups, suggests their susceptibility to injury. The peak impact acceleration has a significant effect on the potential injury of ligaments. Under higher accelerations, most ligaments will reach failure strain in a much shorter time immediately after impact.

This article addresses the dynamics of migration control along the Spanish-African borders and the associated problem of migrant deaths. The past decade and a half has seen rising numbers of migration attempts, large investments in control measures, and resulting geographical and organizational responses on the part of smugglers. Advanced surveillance and interception infrastructure on the border is a necessary but far from sufficient element in controlling unauthorized migration. The growth in the number of migrant deaths seems to result from an increased number of migration attempts. The risk of dying in the attempt appears to be constant or slightly falling.

Background: Hallux valgus is a common condition that may lead to considerable pain and disability. There is also evidence that hallux valgus may impair balance and increase the risk of falling in older people. Although a number of plantar pressure studies have been undertaken in people with and without hallux valgus, little is known about how hallux valgus affects basic gait patterns or the movement of the upper body when walking. Methods: Measurements of temporospatial parameters of gait and acceleration patterns of the head and pelvis were obtained in 71 people (24 men, 47 women) between 75 and 93 (mean 80 ± 4) years of age when walking on both a level surface and a specially designed irregular walkway. Foot problems, vision, peripheral sensation, strength, and reaction time also were evaluated. Results: After adjusting for potential confounders, subjects with moderate to severe hallux valgus were found to exhibit significantly reduced velocity and step length on both walking surfaces and less rhythmic acceleration patterns in the vertical plane when walking on the irregular surface compared to subjects with no or mild hallux valgus. Conclusion: These findings indicate that hallux valgus has a significant detrimental impact on gait patterns that may contribute to instability and risk of falling in older people, particularly when walking on irregular terrain.