scholarly journals Chronotype variation drives night-time sentinel-like behaviour in hunter–gatherers

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170967 ◽  
Author(s):  
David R. Samson ◽  
Alyssa N. Crittenden ◽  
Ibrahim A. Mabulla ◽  
Audax Z. P. Mabulla ◽  
Charles L. Nunn
Keyword(s):  
Natural Selection ◽  
Activity Patterns ◽  
Group Living ◽  
Activity Levels ◽  
Age Classes ◽  
Night Time ◽  
Hunter Gatherers ◽  
The Past ◽  
Time Period ◽  
Mixed Age

Sleep is essential for survival, yet it also represents a time of extreme vulnerability to predation, hostile conspecifics and environmental dangers. To reduce the risks of sleeping, the sentinel hypothesis proposes that group-living animals share the task of vigilance during sleep, with some individuals sleeping while others are awake. To investigate sentinel-like behaviour in sleeping humans, we investigated activity patterns at night among Hadza hunter–gatherers of Tanzania. Using actigraphy, we discovered that all subjects were simultaneously scored as asleep for only 18 min in total over 20 days of observation, with a median of eight individuals awake throughout the night-time period; thus, one or more individuals was awake (or in light stages of sleep) during 99.8% of sampled epochs between when the first person went to sleep and the last person awoke. We show that this asynchrony in activity levels is produced by chronotype variation, and that chronotype covaries with age. Thus, asynchronous periods of wakefulness provide an opportunity for vigilance when sleeping in groups. We propose that throughout human evolution, sleeping groups composed of mixed age classes provided a form of vigilance. Chronotype variation and human sleep architecture (including nocturnal awakenings) in modern populations may therefore represent a legacy of natural selection acting in the past to reduce the dangers of sleep.

The behavioural ecology of dingoes in north-western Australia. II. Activity patterns, breeding season and pup rearing

1992 ◽  
Vol 19 (5) ◽  
pp. 519 ◽  
Author(s):  
PC Thomson
Keyword(s):  
Western Australia ◽  
Activity Patterns ◽  
Scent Marking ◽  
Activity Levels ◽  
Night Time ◽  
Mating Period ◽  
Long Term Study ◽  
Radio Contact ◽  
North Western

This paper reports aspects of a long-term study (1975-84) of the ecology, social organisation and behaviour of dingoes, Canis familiaris dingo, on the lower Fortescue River in Western Australia. In all, 170 dingoes were fitted with radio-collars and tracked from aircraft. Dingoes were sighted during 59% of the 13 618 occasions that they were being radio-tracked during the day. Radio-tracking yielded 31 229 daytime and 3016 night-time locations of radio-collared dingoes. The average duration of radio contact with 146 dingoes was 9 months (range 1-35 months). Dingoes were most active around sunrise and sunset, moderately active during the night, and least active during the heat of the day. Travelling (local meandering and more purposeful movement) was the most commonly witnessed activity. Levels of scent-marking (raised-leg urination and ground-scratching), howling and general activity increased over the 2-3 months prior to the mating period, suggesting that dingoes may have a long pro-oestrus (1-2 months). Whelping took place from mid-May to mid-August (mean date 18 July). The characteristics of natal dens are described. The pattern of activities associated with pup-rearing, including alloparental behaviour, closely followed that of related canids.

scholarly journals Estimación de la edad de guanaco (Lama guanicoe) a partir de los dientes incisivos: un aporte metodológico para la construcción de perfiles de mortalidad / AGE ESTIMATION OF GUANACO (LAMA GUANICOE) BASED ON INCISOR TEETH: A METHODOLOGICAL CONTRIBUTION ...

2017 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Cristian A. Kaufmann ◽  
María Clara Alvarez ◽  
S. Iván Pérez
Keyword(s):  
Age Estimation ◽  
South American ◽  
Crown Height ◽  
Age Classes ◽  
Hunter Gatherers ◽  
Lama Guanicoe ◽  
The Past ◽  
Palabras Clave ◽  
Qualitative Variables ◽  
The Relationship

<p>El guanaco fue el principal recurso para los cazadores-recolectores que habitaron las regiones pampeana y patagónica de Argentina. Este ungulado jugó un rol fundamental en las esferas económica, social e ideológica de estas sociedades durante el Holoceno. En este sentido, comprender la relación entre las poblaciones de humanos y guanacos en el pasado es crucial para la zooarquelogía sudamericana. El objetivo de este trabajo es presentar una metodología que permite estimar la edad relativa de los camélidos a partir del análisis de los dientes incisivos. La muestra se compone de incisivos de 91 guanacos modernos, asignados a diferentes clases de edad. Este análisis incluyó variables cualitativas, tales como el estado de la raíz y de la dentina, así como cuantitativas, como la altura de la corona. Los resultados indican que la combinación de estas variables es un indicador útil para la estimación de la edad en incisivos aislados de guanaco, los cuales son frecuentemente hallados en el registro faunístico.</p><p> </p><p>Palabras clave: Guanaco; Dientes incisivos; Estimación de la edad; Perfil de mortalidad.</p><p> </p><p>Abstract</p><p>The guanaco was the main resource for hunter-gatherers that inhabited the Pampean and Patagonian regions of Argentina. This ungulate played a fundamental role in the economic, social, and ideological spheres of these societies during the Holocene. In this sense, understanding the relationship between human and guanaco populations in the past is crucial to South American zooarchaeology. The aim of this paper is to present a methodology that allows estimating relative ages of guanaco throughout the analysis of the incisor teeth. The sample is composed of incisors from 91 modern guanacos assigned to different age-classes. This analysis included qualitative variables, such as the root and dentine state, and quantitative ones, such as the crown height. The results show that the combination of these variables is a useful indicator for estimating the age of guanacos in isolated incisors, which are usually found in the faunal record.</p><p> </p><p>Keywords: Guanaco; Incisor teeth; Age estimation; Mortality profile.</p>

World Economy: Prospects and Barriers for Recovery

2012 ◽  
pp. 61-83 ◽  
Author(s):  
M. Ershov
Keyword(s):  
World Economy ◽  
Western World ◽  
Short Time Period ◽  
Market Segments ◽  
Junk Bonds ◽  
The Past ◽  
Time Period ◽  
The Us ◽  
Global Liquidity ◽  
Short Time

According to the latest forecasts, it will take 10 years for the world economy to get back to “decent shape”. Some more critical estimates suggest that the whole western world will have a “colossal mess” within the next 5–10 years. Regulators of some major countries significantly and over a short time‑period changed their forecasts for the worse which means that uncertainty in the outlook for the future persists. Indeed, the intensive anti‑crisis measures have reduced the severity of the past problems, however the problems themselves have not disappeared. Moreover, some of them have become more intense — the eurocrisis, excessive debts, global liquidity glut against the backdrop of its deficit in some of market segments. As was the case prior to the crisis, derivatives and high‑risk operations with “junk” bonds grow; budget problems — “fiscal cliff” in the US — and other problems worsen. All of the above forces the regulators to take unprecedented (in their scope and nature) steps. Will they be able to tackle the problems which emerge?

The Evolution of Lead Extraction

2009 ◽  
Vol 5 (1) ◽  
pp. 32
Author(s):  
Melanie Maytin ◽  
Laurence M Epstein ◽  
◽  
Keyword(s):  
Natural Selection ◽  
Lead Extraction ◽  
Significant Morbidity ◽  
Extraction Techniques ◽  
Extraction Technology ◽  
Device Management ◽  
Future Developments ◽  
The Past ◽  
New Methods ◽  
Life Threatening

Prior to the introduction of successful intravascular countertraction techniques, options for lead extraction were limited and dedicated tools were non-existent. The significant morbidity and mortality associated with these early extraction techniques limited their application to life-threatening situations such as infection and sepsis. The past 30 years have witnessed significant advances in lead extraction technology, resulting in safer and more efficacious techniques and tools. This evolution occurred out of necessity, similar to the pressure of natural selection weeding out the ineffective and highly morbid techniques while fostering the development of safe, successful and more simple methods. Future developments in lead extraction are likely to focus on new tools that will allow us to provide comprehensive device management and the design of new leads conceived to facilitate future extraction. With the development of these new methods and novel tools, the technique of lead extraction will continue to require operators that are well versed in several methods of extraction. Garnering new skills while remembering the lessons of the past will enable extraction technologies to advance without repeating previous mistakes.

Introduction

2018 ◽  
Author(s):  
Gianfranco Pacchioni
Keyword(s):  
Industrial Revolution ◽  
Homo Sapiens ◽  
Modern Society ◽  
Full Time ◽  
Human Race ◽  
Hunter Gatherers ◽  
The Past ◽  
The World ◽  
The Universe ◽  
Radical Transformation

About 10,000 years ago, at the beginning of the agriculturalrevolution, on the whole earth lived between 5 and 8 million hunter-gatherers, all belonging to the Homo sapiens species. Five thousand years later, freed from the primary needs for survival, some belonging to that species enjoyed the privilege of devoting themselves to philosophical speculation and the search for transcendental truths. It was only in the past two hundred years, however, with the advent of the Industrial Revolution, that reaping nature’s secrets and answering fundamental questions posed by the Universe have become for many full-time activities, on the way to becoming a real profession. Today the number of scientists across the globe has reached and exceeded 10 million, that is, more than the whole human race 10,000 years ago. If growth continues at the current rate, in 2050 we will have 35 million people committed full-time to scientific research. With what consequences, it remains to be understood. For almost forty years I myself have been concerned with science in a continuing, direct, and passionate way. Today I perceive, along with many colleagues, especially of my generation, that things are evolving and have changed deeply, in ways unimaginable until a few years ago and, in some respects, not without danger. What has happened in the world of science in recent decades is more than likely a mirror of a similar and equally radical transformation taking place in modern society, particularly with the advent ...

scholarly journals Novel approach to modeling high-frequency activity data to assess therapeutic effects of analgesics in chronic pain conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zekun Xu ◽  
Eric Laber ◽  
Ana-Maria Staicu ◽  
B. Duncan X. Lascelles
Keyword(s):  
High Frequency ◽  
Activity Patterns ◽  
Treatment Strategies ◽  
Therapeutic Effects ◽  
Activity Levels ◽  
Activity Data ◽  
Novel Approach ◽  
High Frequency Activity ◽  
Using Data ◽  
Chronic Pain Conditions

AbstractOsteoarthritis (OA) is a chronic condition often associated with pain, affecting approximately fourteen percent of the population, and increasing in prevalence. A globally aging population have made treating OA-associated pain as well as maintaining mobility and activity a public health priority. OA affects all mammals, and the use of spontaneous animal models is one promising approach for improving translational pain research and the development of effective treatment strategies. Accelerometers are a common tool for collecting high-frequency activity data on animals to study the effects of treatment on pain related activity patterns. There has recently been increasing interest in their use to understand treatment effects in human pain conditions. However, activity patterns vary widely across subjects; furthermore, the effects of treatment may manifest in higher or lower activity counts or in subtler ways like changes in the frequency of certain types of activities. We use a zero inflated Poisson hidden semi-Markov model to characterize activity patterns and subsequently derive estimators of the treatment effect in terms of changes in activity levels or frequency of activity type. We demonstrate the application of our model, and its advance over traditional analysis methods, using data from a naturally occurring feline OA-associated pain model.

scholarly journals One Year of the COVID-19 Pandemic in Galicia: A Global View of Age-Group Statistics during Three Waves

2021 ◽  
Vol 18 (10) ◽  
pp. 5104
Author(s):  
Iván Area ◽  
Henrique Lorenzo ◽  
Pedro J. Marcos ◽  
Juan J. Nieto
Keyword(s):  
Intensive Care Unit ◽  
Hospital Admissions ◽  
Age Groups ◽  
Age Group ◽  
Nw Spain ◽  
The Past ◽  
Global View ◽  
Time Period ◽  
Key Variables ◽  
One Year

In this work we look at the past in order to analyze four key variables after one year of the COVID-19 pandemic in Galicia (NW Spain): new infected, hospital admissions, intensive care unit admissions and deceased. The analysis is presented by age group, comparing at each stage the percentage of the corresponding group with its representation in the society. The time period analyzed covers 1 March 2020 to 1 April 2021, and includes the influence of the B.1.1.7 lineage of COVID-19 which in April 2021 was behind 90% of new cases in Galicia. It is numerically shown how the pandemic affects the age groups 80+, 70+ and 60+, and therefore we give information about how the vaccination process could be scheduled and hints at why the pandemic had different effects in different territories.

scholarly journals Metaphors of migration over time

2021 ◽  
pp. 095792652199215
Author(s):  
Charlotte Taylor
Keyword(s):  
Emigration And Immigration ◽  
Emigrants And Immigrants ◽  
Economic Resource ◽  
Historical Discourse ◽  
Continuity And Change ◽  
The Past ◽  
Perception Of Control ◽  
Time Period ◽  
Metaphor Use ◽  
The Uk

This paper aims to cast light on contemporary migration rhetoric by integrating historical discourse analysis. I focus on continuity and change in conventionalised metaphorical framings of emigration and immigration in the UK-based Times newspaper from 1800 to 2018. The findings show that some metaphors persist throughout the 200-year time period (liquid, object), some are more recent in conventionalised form (animals, invader, weight) while others dropped out of conventionalised use before returning (commodity, guest). Furthermore, we see that the spread of metaphor use goes beyond correlation with migrant naming choices with both emigrants and immigrants occupying similar metaphorical frames historically. However, the analysis also shows that continuity in metaphor use cannot be assumed to correspond to stasis in framing and evaluation as the liquid metaphor is shown to have been more favourable in the past. A dominant frame throughout the period is migrants as an economic resource and the evaluation is determined by the speaker’s perception of control of this resource.

scholarly journals Validation of SCIAMACHY limb NO<sub>2</sub> profiles using solar occultation measurements

2011 ◽  
Vol 4 (4) ◽  
pp. 4753-4800
Author(s):  
R. Bauer ◽  
A. Rozanov ◽  
C. A. McLinden ◽  
L. L. Gordley ◽  
W. Lotz ◽  
...  
Keyword(s):  
The Past ◽  
Middle Latitudes ◽  
Solar Occultation ◽  
Time Period ◽  
Vertical Distributions ◽  
Global Coverage ◽  
Scanning Imaging ◽  
Diurnal Effect ◽  
Better Than ◽  
Balloon Measurements

Abstract. The increasing amounts of reactive nitrogen in the stratosphere necessitates accurate global measurements of stratospheric nitrogen dioxide (NO2). Over the past decade, the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on ENVISAT (European Environmental Satellite) has been providing global coverage of stratospheric NO2 every 6 days, which is otherwise difficult to achieve with other systems (e.g. balloon measurements, solar occultation). In this study, the vertical distributions of NO2 retrieved from limb measurements of the scattered solar light from the SCIAMACHY instrument are validated using NO2 products from three different satellite instruments (SAGE II, HALOE and ACE-FTS). The retrieval approach, as well as the sensitivity of the SCIAMACHY NO2 limb data product are discussed, and the photochemical corrections needed to make this validation feasible, as well as the chosen collocation criteria are described. For each instrument, a time period of two years is analyzed with several hundreds of collocation pairs for each year and instrument. The agreement between SCIAMACHY and each instrument is found to be better than 10 % between 22–24 km and 40 km. Additionally, NO2 amounts in three different latitude regions are validated individually, with considerably better agreements in high and middle latitudes compared to tropics. Differences with SAGE II and ACE-FTS below 20 km are consistent with those expected from the diurnal effect.

Pedestrian Activity Among California Adults

2009 ◽  
Vol 6 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Anna E. Mathews ◽  
Natalie Colabianchi ◽  
Brent Hutto ◽  
Delores M. Pluto ◽  
Steve P. Hooker
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Activity Patterns ◽  
Physical Activity Promotion ◽  
Activity Level ◽  
Activity Levels ◽  
Public Health Agencies ◽  
Activity Promotion ◽  
Health Agencies ◽  
Random Digit Dial

Background:The objectives of this study were to assess (1) pedestrian activity levels among adults, (2) where and why adults engage in pedestrian activity, and (3) what adults consider when deciding where to engage in pedestrian activity.Methods:Pedestrian activity was assessed in 12,036 California adults, ≥18 years, using a random digit-dial telephone survey.Results:Significant differences were identified by race, sex, age, and physical activity level in the type, location, and purpose of pedestrian activities. Men engage in pedestrian activity at work, and women engage in pedestrian activity while escorting children to school and running errands. Whites primarily engage in leisure-time pedestrian activity, and non-whites are more likely to engage in pedestrian activity for transportation. Older adults were less active than their younger counterparts.Conclusions:These findings should be considered by public health agencies and their partners as they continue to increase and promote opportunities for pedestrian activity. Additional research is needed to assess older adults’ physical activity patterns and preferences, barriers, and facilitators to effectively tailor physical activity promotion efforts to this at-risk group.

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