Overhead Light Research Articles

Integrating high resolution drone imagery and forest inventory to distinguish canopy and understory trees and quantify their contributions to forest structure and dynamics.

Tree growth and survival differ strongly between canopy trees (those directly exposed to overhead light), and understory trees. However, the structural complexity of many tropical forests makes it difficult to determine canopy positions. The integration of remote sensing and ground-based data enables this determination and measurements of how canopy and understory trees differ in structure and dynamics. Here we analyzed 2 cm resolution RGB imagery collected by a Remotely Piloted Aircraft System (RPAS), also known as drone, together with two decades of bi-annual tree censuses for 2 ha of old growth forest in the Central Amazon. We delineated all crowns visible in the imagery and linked each crown to a tagged stem through field work. Canopy trees constituted 40% of the 1244 inventoried trees with diameter at breast height (DBH) > 10 cm, and accounted for ~70% of aboveground carbon stocks and wood productivity. The probability of being in the canopy increased logistically with tree diameter, passing through 50% at 23.5 cm DBH. Diameter growth was on average twice as large in canopy trees as in understory trees. Growth rates were unrelated to diameter in canopy trees and positively related to diameter in understory trees, consistent with the idea that light availability increases with diameter in the understory but not the canopy. The whole stand size distribution was best fit by a Weibull distribution, whereas the separate size distributions of understory trees or canopy trees > 25 cm DBH were equally well fit by exponential and Weibull distributions, consistent with mechanistic forest models. The identification and field mapping of crowns seen in a high resolution orthomosaic revealed new patterns in the structure and dynamics of trees of canopy vs. understory at this site, demonstrating the value of traditional tree censuses with drone remote sensing.

How a Classroom Failure Improved My Teaching

How a Classroom Failure Improved My Teaching

Earlier Intervention for Medically Fragile Pediatric Inpatient Population

Earlier Intervention for Medically Fragile Pediatric Inpatient Population

Mirid feeding preference as influenced by light and temperature‐mediated changes in plant nutrient concentration in cocoa

AbstractCocoa mirids are the most important insect pests of cocoa in West Africa. This study investigated the effect of environmental parameters that are modulated by overhead shade, that is, light intensity and temperature, on nutrient and phenolic concentrations in cocoa and their subsequent effect on mirid feeding. Eight‐month‐old cocoa seedlings were maintained for 50 days in two growth chambers set to day temperatures of 25 or 30°C. Each chamber had sections with different light intensities (541, 365 and 181 μmol m−2 s−1 photosynthetically active radiation [PAR]). For the field studies at Akim Tafo in Ghana, 8‐month‐old plants of three cocoa clones were subjected to shaded (PAR = 180 μmol m−2 s−1, between 11:00 a.m. and 12:00 p.m.) and unshaded (PAR = 1,767 μmol m−2 s−1, between 11:00 a.m. and 12:00 p.m.) treatments for 50 days after which nutrient measurements and mirid choice tests were carried out. No significant effect of environment was observed on the phenolic concentration of stems under controlled environment chamber conditions. However, in the field, the phenolic concentration of stems was significantly greater for unshaded compared with shaded plants (p = .04). Under controlled conditions, the leaf nitrogen concentration increased slightly with light intensity (p = .003). The same trend was seen in stems but only at 30°C. In the field, the impact of overhead shade on nitrogen varied between cocoa clones. The concentration of carbohydrates in both leaves and stems in the field was higher under unshaded conditions. When subjected to feeding tests, stems from unshaded cocoa had significantly more mirid feeding lesions (p = .003) after 24 hr exposure to mirids compared to shaded cocoa. Mirid feeding therefore appears not to be deterred by the higher phenolic levels but rather there was a preference for cocoa tissue grown under unshaded conditions. These findings highlight the need to consider the growing environment of cocoa clones when screening for varieties with resistance to mirids.

Lighting Control in Patient Rooms: Understanding Nurses' Perceptions of Hospital Lighting Using Qualitative Methods.

This study differs in its methodological approach from previously published research by interpreting qualitative results against existing literature to understand how nurses conceptualize medical-surgical patient rooms as productive settings in relation to lighting, as well as the ways in which nurses believe these spaces could be enhanced for patient satisfaction. Content analysis was used to interpret themes emerging from nurses' subjective responses to open-ended items. Three of the facilities had older, traditional lighting systems; one had a contemporary framework. A theme of environmental control over both overhead and task lighting emerged from data from all items. Although controllability was among the "best" lighting attributes, more refinement is necessary for optimal staff productivity and patient satisfaction. Daylighting was also considered to be among the best attributes. Control over light level via additional dimming capability for patients, as well as additional light sources, was prominent across the four hospitals. Unique to the more modern facility, trespassing of light was problematic for nurses considering the experiences of patients-even where modern models exist, more attention can be paid to the ways in which window shades, and light sources outside of rooms, penetrate spaces and affect users. The finding that nurses and patients desire greater control over the lighting in patient rooms is consistent with Ulrich's theory of supportive design for healthcare and coincides with advances in lighting technology. Despite differences in the level of sophistication in lighting among the four facilities, control continues to be a primary concern for nurses.

Countershading enhances camouflage by reducing prey contrast

A three-dimensional body shape is problematic for camouflage because overhead lighting produces a luminance gradient across the body's surface. Countershading, a form of patterning where animals are darkest on their uppermost surface, is thought to counteract this luminance gradient and enhance concealment, but the mechanisms of protection remain unclear. Surprisingly, no study has examined how countershading alters prey contrast, or investigated how the presence of a dorsoventral luminance gradient affects detection under controlled viewing conditions. It has also been suggested that the direction of the dorsoventral luminance gradient (darkest or lightest on top) may interfere with predators' abilities to resolve prey's three-dimensional shape, yet this intriguing idea has never been tested. We used live fish predators (western rainbowfish, Melanotaenia australis) and computer-generated prey images to compare the detectability of uniformly pigmented (i.e. non-countershaded) prey with that of optimally countershaded prey of varying contrasts against the background. Optimally countershaded prey were difficult for predators to detect, and the probability and speed of detection depended on prey luminance contrast with the background. In comparison, non-countershaded prey were always highly detectable, even though their average luminance closely matched the luminance of the background. Our findings suggest that uniformly pigmented three-dimensional prey are highly conspicuous to predators because overhead lighting increases luminance contrast between different body parts or between the body and the background. We found no evidence for the notion that countershading interferes with predator perception of three-dimensional form.

Impact of Office Modernization on Environmental Satisfaction: A Naturalistic Field Study

A case study was undertaken on one floor of a multi-floor office building in Seattle, WA. Its aim was to offer a straight-forward example for facilities managers, administrators, and researchers alike wishing to perform systematic, naturalistic, mixed-methods research in office spaces that have recently been retrofitted. Changes were made to the floor’s layout, and to the size of employees’ workspaces. New sound-making technology and a modern lighting framework were added. Objective measurements of lighting, acoustics, and indoor air quality were taken and an online questionnaire was distributed to staff to afford subjective measurements of their perceptions about the previous and new open-plan settings. Items concerning satisfaction with workspace layout, size, lighting, acoustics, air quality, and level of input into the retrofit process were asked. After the new space had been used for 1.5 months, occupants reported being more satisfied, in general, than they recalled being in the original setting. The size of personal workspaces and a sense of privacy were especially important to employees. Despite overhead lighting illuminance levels being below recommended industry standards, occupants were not dissatisfied with light levels. The sound masking system was iteratively commissioned based on negative occupant feedback, resulting in purposely setting some areas to exceed or fall short of acoustical performance guidelines; indoor air quality remained unchanged. Differences in quantitative and qualitative findings highlight the importance of gathering self-reported information from occupants in several ways and exploring them carefully to better understand why environmental satisfaction (or dissatisfaction) exists. Employees’ sense of environmental control remained a prominent theme in the data, supporting existing studies in the field of environmental psychology. While perceptions of control did not improve after the retrofit, occupants’ responses about the level of input they had into the retrofit process correlated significantly and positively with their perceptions of environmental satisfaction after its completion. The nuanced findings from this case study’s customized approach to measuring objective environmental stimuli, along with occupants’ environmental perceptions, add to a growing body of literature merging social scientific methodologies with technical environmental assessments for practical use by decision-makers working to satisfy employee preferences.

An in vitro assessment of the accuracy of new and in-use torque-limiting devices

Statement of problemRecent studies have shown that torque-limiting devices (TLDs) do not meet their torque targets and are affected by factors such as the use of the TLDs and the sterilization processes used. PurposeThe purpose of this in vitro study was to investigate the accuracy of TLDs currently in use in the Advance Education Program in Prosthodontics at the New York University College of Dentistry. Material and methodsFive new and 46 in-use TLDs (Nobel BioCare) from the implant kits of the graduate students were evaluated. One investigator was trained and calibrated before testing and after every 10 evaluations. A 3-jaw chuck was mounted on the center of a cap testing device by using the provided mounting screws. A LOCATOR torque driver was clamped into the chuck, and a torque wrench driver was attached to it. The device was placed on a flat table with direct overhead lighting that allowed the investigator to have a consistent view of the notches on the TLDs. A piece of cardboard was attached to the device to ensure that the investigator could not see the readouts. The blinded researcher inserted the wrench and applied the appropriate torque force at the designated notches while another researcher recorded the results. Two readings were made for each TLD at 15, 35, and 45 Ncm. A 2-way ANOVA and an intraclass correlation coefficient to test for intraclinician reliability were performed by using a statistical software program (α=.05). ResultsTwo TLDs were damaged and not tested. The 2-way ANOVA demonstrated no significant difference (P>.05) between graduate students in year 1, 2, and 3 or between the autoclaved and new TLDs. The intraclass correlation coefficient was 0.861 for 15 Ncm, 0.589 for 35 Ncm, and 0.764 for 45 Ncm. ConclusionsIn this in vitro study, new and used TLDs all met the recommended torque values. No significant differences were found among groups, suggesting that autoclaving and use did not affect the accuracy of the TLDs tested.

Better (and Worse) Living through Agribusiness Agribusiness

Better (and Worse) Living through Agribusiness Andrew R. Graybill (bio) Shane Hamilton, Supermarket USA: Food and Power in the Cold War Farms Race. New Haven: Yale University Press, 2018. x + 277 pp. Maps, photographs, notes, and index. $38.00. Joshua Specht, Red Meat Republic: A Hoof-to-Table History of How Beef Changed America. Princeton: Princeton University Press, 2019. xv + 339 pp. Maps, photographs, notes, and index. $27.95. In an episode from the fifth season of The Americans, a recent television drama about Soviet spies living undercover in the United States during the 1980s, an officer from a Soviet bureaucracy visits a Moscow supermarket to investigate corrupt practices in the supply chain. As he explains to the store manager, rumor has it that she receives choice products to sell while many other local markets go without. The manager nervously deflects the officer's questions before trying to buy his silence with a bag of shiny tangerines; the officer politely declines. As he leaves, the camera pans to another character in the series—an American forced into exile in the USSR—who, beneath the wan overhead lighting, scans the barren shelves as other downtrodden customers quietly pick over the sad inventory. And this, the audience infers, is one of the better stores. The scene channels an idea long popular in the United States: namely, that American agricultural abundance—as much as nuclear weapons or stern presidential rhetoric—was an essential factor in U.S. victory over the Soviet Union in the Cold War. The stockpiles found in places like Kroger and Albertsons confirmed the superiority of free-market capitalism in delivering vast quantities of appealing and inexpensive food to the average consumer. Many Americans now take for granted the bounty of the typical U.S. supermarket, a glibness challenged only by the eruption of the COVID-19 pandemic in spring 2020.1 Practically overnight, anxious shoppers—terrified by the prospect of dearth—cleared out supplies of cleaning products and toilet paper, but they also made runs on staples such as flour, yeast, pancake mix, and all manner [End Page 432] of frozen food. Several weeks into the crisis, many stores responded to fears of a looming scarcity by restricting the purchase of meat. Considering that it took the worst global health crisis in a century to shake American faith in the supermarket—or at least the vast and unseen network of supply chains that supports it—the dominance of this ubiquitous institution may seem inevitable. In this telling, a place like Safeway (or its many equivalents) is the natural result of U.S. ingenuity across the decades, characterized by inventions like the mechanical reaper and then the combine, grain elevators, and refrigerated transportation. But a pair of important and engaging new books about the rise and maturation of American agribusiness suggests the limitations of this triumphalist narrative. Together, they highlight some of the improbable twists along the road to the U.S. supermarket and the availability of one of its most popular products: cheap, plentiful beef. And they point to the indispensable (and often hidden) role of the federal government in making it all possible. ________ Joshua Specht's Red Meat Republic comes in a plain brown wrapping, brilliantly evoking the look and even the feel of the butcher paper used to package a slab of store-bought beef. Based on his 2014 doctoral dissertation, Specht's first book takes its place among a recent spate of commodity histories which purport to see the world—or at least the United States—in a grain of sugar, a boll of cotton, or, in this case, a sirloin steak. Such extrapolation poses no small challenge for the author, given that the story of the U.S. cattle industry, particularly the open range era that flourished after the Civil War, has been often told, captured in countless contemporary memoirs as well as a raft of scholarly and popular writing ever since. The first half of the book, with its requisite scene-setting, thus breaks little new ground. In "War," his opening chapter, Specht recounts the familiar tale of the industry's brutal origins, as ranchers—with a critical assist from the U.S...

Epidemic

Epidemic Ann Pancake (bio) At ten o’clock on a thick July night you pull into what you still call home even though you’re thirty-eight years old and own a house yourself. Turn in the dark road and straddle the ruts, because you were passing within seventy-five miles and haven’t seen your parents since Christmas. And because you know, or at least you’ve heard, that your drug-thralled brother won’t be slinking around because he’s found another fool to take him in this month. You greet your mother, holed up in the TV room with her crafts and her gory police shows, and you know your father tottered off to bed an hour ago. And you’re very, very tired, so you pick up your bag and climb the stairs with their faint odor of long-dead animals in the walls. You walk by the open door of your brother’s childhood room. That bed is empty. You move on through to your own old room. It’s your mother’s sewing room now, but your past still sits off to the side: Misty of Chincoteague books, 4-H blue ribbons, high school graduation photo, the artificial flower arrangement you carried in your best friend’s wedding. You slip your bag onto your childhood bed. It might be called an antique by an outsider, but for your family, it’s simply something that’s been around a long time. Only after you grew up and moved away did you realize the mattress was an antique, too. A striped pallet stuffed with cotton batting no thicker than your thumb and first finger held some ways apart. You change into a T-shirt to sleep in. Moths paddle the overhead light. Since you’ve come upstairs, you’ve been touching towards the other darkened rooms, just in case your brother might be sleeping someplace else. No presence touches back. You crawl under the dusty bedspread into unchanged sheets. Preparations for your visits stopped years ago, but the bed is familiar, even a comfort. You pull the covers to your chin. You roll over on your side. And feel under your hip and thigh something long and very hard. Your body—punch to your solar plexus, gorge in your throat—knows instantly. The body knows, but the mind has to see. You flip on the light, drop your feet to the floor, and peel that mattress back. A small dark hole (funny how you see it as a hole before you see what makes that hole). The matte steel of barrel, lengthening, lengthening, as that mattress [End Page 86] unfolds. The swell of chamber. The notched sight. The trigger poised in its ring. Until the walnut stock comes as a reprieve. And you can’t remember charging down the stairs, but then you’re back in the TV room, blurting and sputtering, stupidly waving your arms to show the size of the gun. And your mother looks at you, then replies, as mildly as though you’re complaining about the dirty sheets: “Oh, honey. I’m sorry. He hid them around the house before we went on our trip in March. He must have forgotten that one.” But as she says this, you’re already in the middle of understanding, it’s suddenly inevitable, quickly of course. Your father stashed his not-yet-stolen hunting rifles before his vacation to foil your brother’s constant thefts. Five minutes after your discovery, none of this, including your mother’s indifference, surprises you, and twenty years later, it still doesn’t, but twenty years later, this still does: The disk that birthed into my body as I watched that gun unfold. A hot-sided disk the size of a dime, but heavy, heavy, weightier than I’d imagined a thing that size could be. Birthed into a spot between my navel and my groin, a place inside me I’d never known I had, deeper down than I thought I went. And the sensation the disk carried I’d never imagined either: something flatly sexual crossed with something flatly death. Don’t get me wrong. Not threat of...

Quassia amara L. diameter and total height under different light conditions: implications for the management of agroecosystems

Quassia amara L. is a semi-sciophyte species that can be found growing as a large shrub or a small tree in Neotropical rainforests. It is traditionally harvested as a non-wood forest product for culinary, medicinal and insecticidal uses. Lack of knowledge on the ecological conditions that support tree growth limits the development of sustainable forest management plans of natural forests and the development of new agroecological cultivation models. The overall objectives of the present work are to (1) compare the Quassia amara L. growth in different forest structures; (2) evaluate the impact of light conditions on Quassia amara L. diameter growth, total height growth and height–diameter relationship and (3) discuss implications for the sustainable management of the species in agroecosystems. Light conditions are characterized at the tree level by the crown illumination index (cii), which is a visual and ordinal index. Results show that tree growth varies between plots with different forest structures and light conditions. The cii was able to characterize light conditions. Best light conditions were different for diameter and total height growth: cii value of 5.0 (tree crown completely exposed to overhead and lateral direct light) and cii value of 3.5 (tree crown exposed to some vertical/overhead direct light and low direct light), respectively. The cii did not affect the height–diameter relationship. A value of cii equal to 4 was found as an intermediate condition and recommended for the establishment of new agroecosystems including the Quassia amara L.

Closed-Course Human Factors Evaluation of Marking and Marker Visibility

Raised retroreflective pavement markers (RRPMs) are commonly used to provide nighttime delineation of roadways. Although RRPMs are visible during dry conditions, they provide their greatest benefit during wet-night conditions, when typical pavement markings become flooded and lose their retroreflectivite properties. Naturally, the retroreflectivity of RRPMs degrades over time as a result of traffic, ultraviolet light, precipitation, and roadway maintenance activities. Subsequently, it is necessary to examine the relationship between driver performance and the condition of the RRPMs. To assess visibility relative to RRPM condition, study participants rode in the passenger seat of a vehicle operated by a member of the research team, traveling at approximately 15 mph, for two laps around a closed course. Throughout each lap of the course, nine treatments consisting of RRPMs or preformed pavement marking tape of various retroreflectivity levels diverged from a center line to either the right or left. Participants indicated when they could tell which direction the treatment diverged, which was recorded using a GPS unit. A generalized linear model was estimated on a dataset constructed by pairing the observed distances from various treatments with demographic information about each participant. The analysis indicates the distance at which a particular treatment would be visible, which can then be converted to preview time to assess treatment adequacy for a variety of speeds. The RRPM treatments generally provided adequate preview time for older drivers based on the extant literature; however, the preformed pavement marking tape was less adequate at higher speeds and under overhead lighting.

The effectiveness of light-emitting diode lighting for providing circadian stimulus in office spaces while minimizing energy use

Architectural lighting has traditionally addressed visual performance and horizontal illuminance on the work plane, later focussing on energy efficiency, while only recently paying particular regard to human health outcomes. The present study evaluated the effectiveness of several light-emitting diode lighting strategies for delivering circadian stimulus to occupants of a typical office space while minimizing energy use. The study employed photometric simulations in a typical open-office space, delivering a criterion circadian stimulus of 0.3 to calculation points modelled at the simulated occupants’ eye level. Six luminaire types, two luminous intensity distributions, six spectral power distributions and two horizontal illuminances were evaluated, resulting in 144 unique lighting conditions. Additionally, the study calculated the discomfort glare for selected luminaires with the highest total lumen output, smallest aperture and direct-only luminous intensity distributions at the higher of the two horizontal illuminances (500 lx). The most impactful strategy involved supplementing common overhead lighting with a desktop luminaire delivering light directly to the simulated office occupants’ eyes, which provided greater circadian stimulus and used less energy than overhead luminaires that were capable of delivering the criterion circadian stimulus of 0.3.

Building value proposition for interactive lighting systems in the workplace: Combining energy and occupant perspectives

Today, new lighting technologies are rapidly changing energy savings goals and the ways in which those savings are identified and captured. As occupant expectations concerning indoor comfort and well-being are transforming lighting design and engineering solutions, research concerning systems that afford more interaction between occupants, overhead lighting, and local (task) lighting is prudent. This study builds a value proposition by determining risk-based energy savings potential of interactive lighting system while evaluating programmatic success through the measurement of occupants’ psychosocial variables. Post-retrofit data supplied by an overhead lighting control system were combined with empirical energy consumption data from individual tunable desk lamps for a probabilistic return on investment (ROI) analysis. Descriptive and correlational analyses were done to link employees’ environmental perceptions with energy consumption. Even for a modestly energy efficient office building that underwent a lighting retrofit in 2011, it is possible to recover the cost of an interactive lighting investment in nine years. Probabilistically, the rebate appears to be the most important factor in increasing ROI. Occupants perceived overall improvement to the lighting environment after desk lamps had been installed, and that a ‘blending’ had been achieved between task and overhead lighting. The paper proposes a generalizable mixed-methodology to evaluate potential savings. Interactive lighting systems are representative of future building systems that require more human interaction and are prone to irregular operational loads. This research may help facility managers find practical solutions based on existing and emerging technologies to leverage readily available data to aid decision-making processes.

PRINCIPLES OF FORMATION OF A MULTIFUNCTIONAL CENTERS FOR TRAINING EXTREME SPORTS IN KURSK

The purpose of this paper is to identify the basic principles of formation of a multifunctional complex for extreme sports. It includes a comparative analysis of extreme sports facilities in Kursk as well as a number of previously studied similar projects and existing buildings by Russian and foreign architects. The authors of the paper propose a sports complex that fits into the existing architecture of the city. New technologies have been introduces to implement the design of such complex objects as a wind tunnel, a deep-water diving pool, a large-span indoor skate hall with seats for spectators and overhead light. All these elements have been taken from the projects of well-known architectural firms, such as eXtreme Architects, White Studio, Moko Architects, as well as other foreign projects of Danish and Norwegian architects. The authors also considered some ideas on the reconstruction of industrial facilities, such as a fan depot or a silo tower, which were converted into multifunctional sports complexes. The social, economic and environmental aspects of designing such an object have been taken into consideration. The authors give the regulatory framework including the fire safety requirements, requirements on building maintenance by limited mobility populations (MH), the impact on the environment. Moreover, the authors mention building regulations, which establish requirements to the equipment, inventory and the space of the whole complex. The article examines the importance of building a multifunctional complex for practicing extreme sports, and also confirms the relevance of such sports in Kursk.

Application of Dimming Compensation Technology Via Liquid Crystal Lens for Non-Imaging Projection Laser Systems

The main purpose of this paper is to explore a newly developed optical design, then to further improve the overhead lighting contrast in the laser projector module. In terms of the structural design of the projector, a liquid crystal lens array was used as the local dimming system for the light source, in order to achieve the objective, which was to significantly improve the contrast facility of the projection system. Second, in terms of the design of the light source, the output method for the light source was a laser light source employing arrays of micro-scanning. The main purpose was to compensate for the dim spots in the hole between the lenses in each unit of the liquid crystal when the liquid crystal lens array was locally dimmed, and thus significantly improving the contrast facility of the projection system. In terms of the software simulation, a liquid crystal lens array was used to simulate a pore size of 2.0 mm and focal lengths of 9 cm and 23 cm. The end effect gave good control and adjustment of the bright and dark areas during local dimming of the projector’s imaging chip components. For a single laser source, the maximum contrast for local dimming was about 128:1, 438:1, and 244:1, for the Red (R), Green (G), and Blue (B) optical paths, respectively. The light efficiency scores were approximately 20.91%, 20.05%, and 24.45%, for the R, G, and B optical paths, respectively. After compensation using a micro-scanning light source, the defect of having dim spots between the pores was remedied, and the light adjustment area became more uniform while the contrasts became smaller. The maximum contrasts were approximately 52:1, 122:1, and 110:1, for the R, G, and B optical paths, respectively. For the projector, when the liquid crystal lenses were not transmissive, the maximum uniformity scores were 82.25%, 87.15%, and 88.43%, for the R, G, and B optical paths, respectively.

Effects of daytime intra-canopy LED illumination on photosynthesis and productivity of bell pepper grown in protected cultivation

In the past decade, light-emitting diodes (LEDs) have been replacing most other types of light sources. One emerging use for LEDs in horticulture is ‘intra-canopy illumination’ or ‘LED-interlighting’, feasible owing to their low heat output and small physical size. The interlighting technique, typically implemented in environmentally-controlled greenhouses also supplemented with overhead lighting, is mostly relevant for high-wire vegetable cultivation, in which self-shading results in light limitations for a large fraction of the canopy. Interlighting has been shown to increase the yield and/or improve fruit quality in all-year round greenhouse crops such as tomato, cucumber and sweet pepper. In this work, we utilized daytime supplemental intra-canopy LED illumination for sweet pepper grown in high-density ‘Spanish’ trellis systems within passive high tunnels in the Jordan Valley, Israel (latitude ˜32 °N). While canopy top at these conditions is not light-limited, extensive deep shading of the inner canopy is a disadvantage. In two experiments carried out in two separate seasons, the supplemental lighting, which enhanced the photosynthetic rates of the inner canopy foliage by 3.5- to 5.7-fold, resulted in significant increase (˜30%) of the fruit yield during the spring season. The added yield was attained by higher fruit numbers, with no notable effects on fruit size or weight. Our results raise the prospect that LED-interlighting may be a useful practical tool for maximizing fruit production, even in geographical regions of ample sunlight.

Burnout in Surgery Viewed Through the Lens of Psychological Safety.

Midway through a complex abdominal operation, a surgical attending, known for explosive tirades and the occasional flying forceps, noticed the bare handle of the overhead light was stained with blood. As each team member changed their gloves, he demanded to know where the sterile cover was and who h

A Follow-Up Study of the Effects of An Arm Support Exoskeleton on Physical Demands and Task Performance During Simulated Overhead Work

OCCUPATIONAL APPLICATIONSThis study supports that use of an arm-support exoskeleton (ASE) can lower the activity of shoulder and lower trunk muscles during an overhead drilling and a light assembly task, and also improve work quality in terms of the number of errors made during drilling. Integrating the findings from earlier studies, though, the current results suggest that such benefits of ASE use likely depend on the specific ASE and work tasks in which it is used. Further, a decrease in the number of drilling errors with the fixed drilling pace used here can be explained by a speed-accuracy tradeoff. In practice, this tradeoff has implied that when an ASE is provided, workers may need a reasonable training/acclimation period with an ASE, to develop a mental model and an optimal work strategy to adopt to their ASE-enhanced physical capacity without any adverse consequences.TECHNICAL ABSTRACT Background: Overexertion and bodily reaction remain leading causes of work-related musculoskeletal disorders. Occupational use of an exoskeleton has been recognized recently as an alternative intervention approach to reduce physical demands and fatigue experienced in a range of occupational tasks. Purpose: This study replicated many aspects of an earlier study of using an arm-support exoskeleton (ASE) during simulated overhead drilling and light assembly (Kim et al., 2018), and was complete to reexamine the beneficial effects of ASE and determine if a speed-accuracy tradeoff might explain the increase in the number of errors reported in the noted earlier study. Methods: In a controlled lab-based experiment, 12 gender-balanced participants performed a simulated overhead repetitive drilling (at 1 hole per 10 s) and a light assembly task at two different work heights, both with and without a commercial ASE. Activity of shoulder and lower trunk muscles, perceived discomfort, and drilling performance were measured. Results: Using the ASE reduced peak and median normalized muscle activity levels, respectively, by up to 52.5% and 60.6% for the shoulder, and ∼29% and ∼16% for the lower trunk. Reductions in shoulder muscle activity and perceived discomfort were often more substantial at the overhead work height. Using the ASE also led to fewer drilling errors (up to ∼92% reduction), especially with a heavier tool and/or at the overhead work height. Conclusions: This study supplements earlier evidence that supports the efficacy of ASE use in reducing physical demands of the upper extremity and the lower back during overhead work. However, the latter “secondary” benefit, beyond the specific ASE design focus, is likely conditional on the specific ASE design and the specific work task in which it is used. Effects of an ASE on drilling task performance were also task-specific, dependent on how task pacing is controlled and consistent with a traditional speed-accuracy tradeoff.

Quick learning, quick capture: largemouth bass that rapidly learn an association task are more likely to be captured by recreational anglers

Individuals show consistent differences in their approach to novel tasks (i.e., “cognitive syndromes”), whereby “fast” individuals are bold and solve new problems quickly compared to “slow” individuals. While a “fast” approach can be advantageous in some situations, these individuals are often more likely to make mistakes and subject themselves to greater risk, including from predation. What is unknown is how these tendencies impact survival in environments where humans constitute a predatory risk (such as the case of fish targeted by commercial or recreational fishing). To address this gap, we assessed learning performance in 60 largemouth bass Micropterus salmoides using an active-avoidance task that required fish to learn to associate a conditioned stimulus (overhead light) with an unconditioned aversive stimulus (chasing with a net) to successfully shuttle through a small opening to a safe area of an aquarium. These same fish were also tested for proactivity in a restraint test (frequency of leaping to escape a net out of water) before being subjected to angling trials in a naturalistic pond setting. Performance on the active-avoidance task was positively associated with angling vulnerability, as individuals captured by anglers also successfully shuttled on nearly twice as many trials as uncaptured fish. Proactivity was not associated with angling vulnerability or learning performance. These results indicate that a fast cognitive strategy may be maladaptive for fish populations subjected to angling. In addition, because cognitive performance is heritable, fisheries selection based on cognitive traits could cause an evolutionary shift toward slow learning strategies in exploited populations. Individual behavioral and cognitive traits can be linked with fitness, especially in human-altered environments. For many freshwater fish, recreational angling by humans poses a major threat, with some individual fish being more vulnerable to capture than others. However, no work has defined whether cognitive traits are linked with an individual’s vulnerability. To address this, we conducted a study examining if learning performance is linked to angling vulnerability in largemouth bass, a popular sportfish species. We found that fish that learned to associate a light with a negative stimulus (chasing with a net) and successfully avoid chasing were more likely to be caught in an angling trial. This means that, for targeted species, a fast learning strategy is disadvantageous, and that heavily exploited populations could experience evolutionary shifts toward slower learning speed due to the selective capture of fast-learning individuals.