A promising approach that can be used to guide “breeding for manipulation” is the use of plant and robot geometric models to co-design tree structures and machines to optimize manipulation reachability and throughput . Also, the use of large numbers of simpler, cheaper actuators that approach plants from different positions has shown promise in terms of reachability , and could be adopted to increase overall throughput.Agricultural robotics enable sensing and interacting with crops at fine spatial scales, even at the level of individual plants or plant parts. Thus, they enable high-throughput phenotyping for breeding improved crop cultivars, and ultra-precise farming, which is a key technology for increasing crop production in a sustainable manner. They can also generate crop-related data that can be used to increase food safety and traceability, and to optimize crop management. Furthermore, agricultural robots can reduce our dependence on unskilled farm labor, which is diminishing in many countries. Also, the emerging paradigm of replacing large conventional agricultural machines with teams of smaller autonomous vehicles could open up possibilities for dramatically changing the way we cultivate crops. Small machines reduce drastically soil compaction and are not necessarily restricted to crop rows; hence, they could be used to establish alternative, productive crop patterns that incorporate mixed cropping, which is known to reduce pest pressures and increase biodiversity. To accomplish their tasks, agricultural robotics face significant challenges. Their mechanical embodiments, electronics, and their sensing, perception and control software must operate with accuracy, repeatability, reliability and robustness under wide variations in environmental conditions; diversity in cropping systems; variation in crop physical and chemical characteristics and responses to environment and management,blueberry containers due to intraspecies biological variation; diversity and complexity of plant canopy structures. Essentially, agricultural robotics must combine the advanced perception and manipulation capabilities of robotic systems, with the throughput, efficiency and reliability of hard automation systems, in a cost-effective manner.

Sleep timing and duration in humans are determined in part by a master circadian clock entrained to local time by retinal inputs encoding environmental light-dark cycles. The clock is phase delayed by light in the evening and early night, and advanced by light in the late night and early morning. With industrialization and on-demand access to electric lighting, exposure to evening light has increased, while exposure to natural light during the day has decreased. The expected net effect is a delay in the phase at which the circadian clock aligns with local time, and thus a delay in the timing of the circadian sleep-wake cycle. Depending on an individual’s social schedule , this may result in a significant misalignment between biological time and social time, a state known as social jetlag. If sleep onset is delayed, but wake onset is fixed by the social schedule, then nocturnal sleep will be restricted. Epidemiological studies have uncovered associations between short sleep and population health, while experimental studies support a causal role for sleep restriction in metabolic and other health disorders currently described as epidemic. This leads to conjecture that a significant portion of the population in industrialized societies may sleep less than is physiologically optimal and that this may contribute to negative trends in population health. Although the logic supporting this conjecture is compelling, empirical support for the argument that industrialization has caused chronic sleep restriction is weak because information about sleep duration prior to widespread availability of electric lighting is anecdotal and based on self-report. Self-reports typically overestimate sleep, compared to objective measures such as actigraphy and polysomnography. Consequently, the degree to which sleep duration has declined with industrialization may be overestimated and is controversial. Trends over the past several decades within already industrialized societies are equivocal, with some studies showing increases, others showing decreases, and some showing no systematic change in sleep length.Another way to estimate the impacts of industrialization on sleep is to study sleep in indigenous communities living traditional lifestyles without electric lighting. Recently, several studies have used wrist-worn accelerometers and light sensors to examine sleep patterns in communities with little reliable access to electric lighting.

The findings generated from these studies have been variable. Daily sleep duration was observed to be unexpectedly short in traditional hunting and gathering societies in Africa and South America, an agrarian society in Madagasgar, and a pastoralist society in Namibia. By contrast, sleep duration was comparatively long in a traditional horticultural society of Papa New Guinea, and in an Argentinian society who were traditionally hunter-gatherers and showed a marked seasonal variation. In cases where societies are transitioning to electricity, groups with access to on-demand artificial lighting showed a delay in nocturnal sleep timing compared to groups without access . In some, but not all cases, delayed sleep was associated with reduced sleep duration. These results indicate that lifestyle may be an important determinant of habitual sleep duration and provide evidence for an effect of on-demand electric lighting on sleep timing and duration. To further examine the impact of lifestyle and electric lighting on sleep, we used actigraphy to measure sleep timing and duration in indigenous Ni-Vanuatu living traditional, small-scale subsistence lifestyles on Tanna Island, Vanuatu, in south pacific Melanesia. This study population provides some unique advantages, including homogeneity of ethnicity and lifestyle on the island, little seasonal variation in climate and daylength, and the availability of an electric grid in coastal but not inland villages, permitting a within-society comparison of sleep with and without access to on-demand electric lighting. Also, the latitude of Tanna Island, and thus the annual variation in photoperiod, is very close to the latitude of several hunter-gatherer societies previously shown to exhibit short sleep, thus permitting cross-cultural comparisons with a natural control for daylength.We recruited 91 adults living on Tanna Island to participate in our study. Forty-five of the participants lived in coastal villages with on-demand access to electricity, and 46 participants lived in villages that were up to 10 km inland and beyond the electric grid. Some data were lost due to equipment failure or were excluded due to non-compliance , leaving final sample sizes of 39 coastal participants and 43 inland participants .

Participants in both communities live similar lifestyles and rely primarily on small-scale farming for a livelihood.Data were collected from males, females, and females who were currently breastfeeding. It was expected that breastfeeding would lead to higher levels of sleep disruption due to mother-infant co-arousal, therefore breastfeeding females were maintained as a separate sample. Other females were not breastfeeding at the time of data collection and the ages of their children were over 2 years. Because fathers on Tanna Island typically take a less active role than the mother in infant rearing, it was deemed acceptable to collect males as one homogenous group irrespective of “father” status. Age and birthdays are not commonly tracked, so when documentation of age was unavailable, participant ages were estimated visually or relative to the birth of peers. Of those included in the final analysis, demographic variables and other sample characteristics are provided in Table 1. We obtained research permits from the Vanuatu Cultural Centre as well as permission from the elders and chiefs in the host communities. Participants were recruited by word of mouth. We explained the details of the study and obtained informed consent verbally from each participant, as outlined by the Office of Research Ethics at Simon Fraser University, Burnaby BC, Canada. Gifts equivalent to $5 CAD were given for participation. All procedures were performed in accordance with relevant guidelines and regulations and approved by Simon Fraser University.Sources of light at night were most often a singular incandescent light bulb inside dwellings powered by electrical grid ,best indoor plant pots and/or small solar powered LED lights . Solar torches were placed on the floor to facilitate household duties or were carried by hand when walking through the village. Light intensity provided by the torches did not exceed 2 lux, measured at 1-meter distance using the Actiwatch-2 light sensor . During the dates of this study, all participants from communities with access to electricity reported using artificial lights. Although seven participants living in electric communities did not have working electricity at the time of data collection, they each used solar torches, and reported exposure to electric light. Most of the participants from villages without electricity either owned or shared solar torches for use at night, and daily evening use was reported by 84% of participants in non-electric communities. Electronic devices were almost non-existent with the exception of some basic mobile phones, which were not a common source of light at night, especially in villages of the electric grid as there was no ready access to charging stations.Sleeping arrangements were variable, but most sleeping spaces consisted of blankets or foam mattresses on grass woven mats on the floor of the dwelling . Floors were commonly wood plank, or hard packed ground. Co-sleeping is typical on Tanna Island; all participants in this study shared sleeping quarters with multiple children or adults. Sleeping spaces were shared by immediate family , and sometimes with extended family as well . Sleeping arrangements are often flexible and can change readily. Traditional homes are made of local natural materials, carefully constructed to withstand cyclones Separate dwellings are used for sleeping and cooking.

A few dwellings incorporated cement or tin components . Little time is spent inside during the day. Temperature and humidity in typical sleeping spaces were measured with iButtons sampling at 20-minute intervals throughout the study interval. Te iButtons were placed in representative huts in one electric village and one non-electric village. Temperature in the non-electric village during this period averaged ~24.6 °C in the day and ~22.9 °C at night, with an average daily range of 3.9±1.8°C. Electric villages were slightly warmer and drier, averaging ~25.9 °C in the day and ~23.9 °C at night, with a daily range of 3.6±1.8 °C. Te daily temperature minimum occurred at ~06:20h, and the maximum between 13:20–14:00h, in both communities.Although coffee beans are exported from Tanna Island, cafeinated beverages are not commonly used or readily available in the villages studied. All men drink a beverage of kava root, which, although only a few of its constituents have been studied, has been found to have mild sedative, anxiolytic, and antinociceptive/analgesic properties. Sixty-five percent of male participants reported drinking kava on a daily basis. Women are not traditionally permitted to drink kava for leisure nor are they permitted to participate in Kava ceremonies. Food consists primarily of locally cultivated foods, such as root vegetables , seasonal fruit , and on occasion purchased rice, and chicken, beef, fish or pork for ceremonies/celebrations. Cooking takes place over a fire, or with hot stones in an earth oven cooking pit. Breakfast and dinner times were regimented but flexible, and men who attended the nakamals would often eat late. Lunch times were not regimented . Although both community types practice primarily subsistence horticultural lifestyles, 23% of the population of each community type report spending some time participating in wage labour. Farming is the primary daily activity for 93% of the non-electric community members compared to 41% of the electric community members, who report spending more time on other daily activities within the village . Most women report their primary evening activity to be caring for children and attendance at church groups, whereas men report spending time in the nakamal for kava drinking . Bislama is the national language in Vanuatu, but many distinct indigenous oral languages exist on Tanna, and can vary even between nearby villages. Although some terms exist to refer to times of the solar day, residents of Tanna Island do not quantitatively track time within a day , and there are no designated work and free days. Alarm clocks were not used by the participants of this study. Chickens and small pigs wander freely through the villages and often alert residents to sunrise. Individuals do report taking days of from agrarian responsibilities, but working in the garden on these days is replaced with obligations for religious worship . Formal education is not common, but is increasing in prevalence, especially for villages in close proximity to a school, which is the case for electric villages. Morning social obligations included early awakening by some women to prepare children for school , or to travel to Wednesday market to sell produce to make money for school fees. We did not collect information on the prevalence of school attendance but as noted, electric villages where closer to schools or to roads where vehicles travel.