The Adoption of the Bow and Arrow: A Model Based on Experimental Performance Characteristics

2013 ◽  
Vol 78 (3) ◽  
pp. 553-569 ◽  
Author(s):  
Steve A. Tomka
Keyword(s):  
Experimental Study ◽  
Long Range ◽  
New World ◽  
Prey Species ◽  
Game Species ◽  
Experimental Performance ◽  
Hunting Strategies ◽  
Bow And Arrow ◽  
Game Hunting ◽  
Over Time

AbstractThe timing of the arrival of the bow and arrow in the New World and reasons for its adoption have long been discussed by archaeologists. It typically has been assumed that the bow and arrow provided mechanical and physical advantages over the atlatl and dart, particularly in long-range killing power. This experimental study examines the effectiveness of traditional bows and arrows to deliver lethal wounds to prey species of different sizes. The results suggest that the bow and arrow was effective in hunting prey species such as antelope and deer but ineffective in bringing down larger animals unless changes in hunting strategies were adopted. In contrast, the atlatl and dart would have excelled in large game hunting. It is proposed that the adoption of the bow and arrow and the abandonment of the atlatl and dart were conditioned by their distinct performance advantages and changes in the game species targeted over time.

scholarly journals Partnership among hospitals to reduce healthcare associated infections: a quasi-experimental study in Brazilian ICUs

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ladjane Santos Wolmer de Melo ◽  
Maria Verônica Monteiro de Abreu ◽  
Bernuarda Roberta de Oliveira Santos ◽  
Maria das Graças Washington Casimiro Carr ◽  
Maria Fernanda Aparecida Moura de Souza ◽  
...  
Keyword(s):  
Experimental Study ◽  
Length Of Stay ◽  
Public Hospitals ◽  
Incidence Density ◽  
Healthcare Associated Infections ◽  
Collaborative Project ◽  
Quasi Experimental ◽  
Tract Infections ◽  
Healthcare Associated ◽  
Over Time

Abstract Background Healthcare-associated infections (HAIs) are relevant in developing countries where frequencies can be at least 3 times higher than in developed countries. The purpose of this research was to describe the intervention implemented in intensive care units (ICUs) to reduce HAIs through collaborative project and analyze the variation over 18 months in the incidence density (ID) of the three main HAIs: ventilator associated pneumonia (VAP), central line-associated bloodstream infections (CLABSIs) and catheter-related urinary tract infections (CAUTIs) and also the length of stay and mortality in these ICUs. Methods A quasi-experimental study in five public adult clinical-surgical ICUs, to reduce HAIs, through interventions using the BTS-IHI “Improvement Model”, during 18 months. In the project, promoted by the Ministry of Health, Brazilian philanthropic hospitals certified for excellence (HE), those mostly private, certified as excellence and exempt from security contributions, regularly trained and monitored public hospitals in diagnostics, data collection and in developing cycles to improve quality and to prevent HAIs (bundles). In the analysis regarding the length of stay, mortality, the IDs of VAP, CLABSIs and CAUTIs over time, a Generalized Estimating Equation (GEE) model was applied for continuous variables, using the constant correlation (exchangeable) between assessments over time. The model estimated the average difference (β coefficient of the model) of the measures analyzed during two periods: a period in the year 2017 (prior to implementing the project) and in the years 2018 and 2019 (during the project). Result A mean monthly reduction of 0.427 in VAP ID (p = 0.002) with 33.8% decrease at the end of the period and 0.351 in CAUTI ID (p = 0.009) with 45% final decrease. The mean monthly reduction of 0.252 for CLABSIs was not significant (p = 0.068). Length of stay and mortality rates had no significant variation. Conclusions Given the success in reducing VAP and CAUTIs in a few months of interventions, the achievement of the collaborative project is evident. This partnership among public hospitals/HE may be applied to other ICUs including countries with fewer resources.

scholarly journals Revealing the spatial shifting pattern of COVID-19 pandemic in the United States

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Di Zhu ◽  
Xinyue Ye ◽  
Steven Manson
Keyword(s):  
United States ◽  
Long Range ◽  
Network Optimization ◽  
Network Modeling ◽  
The United States ◽  
Standard Series ◽  
Time And Space ◽  
Long Range Interactions ◽  
Dynamic Relationships ◽  
Over Time

AbstractWe describe the use of network modeling to capture the shifting spatiotemporal nature of the COVID-19 pandemic. The most common approach to tracking COVID-19 cases over time and space is to examine a series of maps that provide snapshots of the pandemic. A series of snapshots can convey the spatial nature of cases but often rely on subjective interpretation to assess how the pandemic is shifting in severity through time and space. We present a novel application of network optimization to a standard series of snapshots to better reveal how the spatial centres of the pandemic shifted spatially over time in the mainland United States under a mix of interventions. We find a global spatial shifting pattern with stable pandemic centres and both local and long-range interactions. Metrics derived from the daily nature of spatial shifts are introduced to help evaluate the pandemic situation at regional scales. We also highlight the value of reviewing pandemics through local spatial shifts to uncover dynamic relationships among and within regions, such as spillover and concentration among states. This new way of examining the COVID-19 pandemic in terms of network-based spatial shifts offers new story lines in understanding how the pandemic spread in geography.

Transmission mechanisms of NMR long-range J(13C,19F) scalar couplings in 1-F,4-X-cubanes: a DFT and experimental study

2006 ◽  
Vol 104 (4) ◽  
pp. 485-492 ◽  
Author(s):  
RubéN H. Contreras ◽  
Ángel L. Esteban ◽  
Ernesto DÍez ◽  
Nicholas J. Head ◽  
Ernest W. Della
Keyword(s):  
Experimental Study ◽  
Long Range ◽  
Scalar Couplings ◽  
Transmission Mechanisms

An Experimental Study of Cache Recovery By Hoarding Willow Tits After Different Retention Intervals

Behaviour ◽  
1997 ◽  
Vol 134 (11-12) ◽  
pp. 881-890 ◽  
Author(s):  
Camilla Kunz ◽  
Anders Brodin
Keyword(s):  
Experimental Study ◽  
Parus Montanus ◽  
Individual Preferences ◽  
Cache Recovery ◽  
Retention Intervals ◽  
Over Time ◽  
Better Than

AbstractWe allowed seven willow tits, Parus montanus, to store and retrieve with retention intervals of 1, 7, 21 and 56 days, in four experimental rooms. Retrieval success decreased over time, indicating a decaying memory for cache locations. Compared to what could be expected by chance, retrieval success was better after all retention intervals. Our results suggest that - after the longer retention intervals - this might depend on preferences for certain types of caching locations rather than memory. If both general and individual preferences are controlled for, birds retrieved significantly better than expected one and seven days after storing, but not later than that.

An Experimental Study of Nonequilibrium Carbon Dioxide/Oil Interactions

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1768-1783 ◽  
Author(s):  
Mahmood Reza Yassin ◽  
Ali Habibi ◽  
Ashkan Zolfaghari ◽  
Sara Eghbali ◽  
Hassan Dehghanpour
Keyword(s):  
Carbon Dioxide ◽  
Experimental Study ◽  
Natural Convection ◽  
Visual Cell ◽  
Bulk Oil ◽  
High Pressure High Temperature ◽  
Light Oil ◽  
Condensing Flows ◽  
Carbon Dioxide Co2 ◽  
Over Time

Summary In this study, we use a custom-designed visual cell to investigate nonequilibrium carbon dioxide (CO2)/oil interactions under high-pressure/high-temperature conditions. We visualize the CO2/oil interface and measure the visual-cell pressure over time. We perform five sets of visualization tests. The first three tests aim at investigating interactions of gaseous (g), liquid (l), and supercritical (sc) CO2 with a Montney (MTN) oil sample. In the fourth test, to visualize the interactions in the bulk oil phase, we replace the opaque MTN oil with a translucent Duvernay (DUV) light oil (LO). Finally, we conduct an N2(sc)/oil test to compare the results with those of CO2(sc)/oil test. We also compare the results of nonequilibrium CO2/oil interactions with those obtained from conventional pressure/volume/temperature (PVT) tests. Results of the first three tests show that oil immediately expands upon injection of CO2 into the visual cell. CO2(sc) leads to the maximum oil expansion followed by CO2(l) and CO2(g). Furthermore, the rate of oil expansion in the CO2(sc)/oil test is higher than that in CO2(l)/oil and CO2(g)/oil tests. We also observe extracting and condensing flows at the CO2(l)/oil and CO2(sc)/oil interfaces. Moreover, we observe density-driven fingers inside the LO phase because of the local increase in the density of LO. The results of PVT tests show that the density of the CO2/oil mixture is higher than that of the CO2-free oil, explaining the density-driven natural convection during CO2(sc) injection into the visual cell. We do not observe either extracting/condensing flows or density-driven mixing for the N2(sc)/oil test, explaining the low expansion of oil in this test. The results suggest that the combination of density-driven natural convection and extracting/condensing flows enhances CO2(sc) dissolution into the oil phase, leading to fast oil expansion after CO2(sc) injection into the visual cell.

Raptor Prey Remains

2020 ◽  
Author(s):  
Ed Drewitt
Keyword(s):  
Feeding Ecology ◽  
Prey Species ◽  
Local Level ◽  
Body Parts ◽  
Change Over Time ◽  
The Common ◽  
Prey Remains ◽  
Over Time ◽  
Prey Populations

Are you curious about the remains of an animal you have found? This compilation of the most likely found body parts of animals eaten by raptors will help you identify your discovery. Including over 100 species of bird and mammal prey of raptors such as sparrowhawks, peregrines and hen harriers, this photographic guide highlights the common feathers, fur and other body parts found at raptor nests, roosts, plucking posts and other opportunistic spots. Discovering what raptors eat is an important part of confirming their feeding ecology and how this might change over time, vary on a local level or in response to changing prey populations, as well as dispelling myths and assumptions about what certain raptor species eat. Diet studies are vital for the conservation of raptor species; the more we know about what they need for survival the more we can predict and plan long-term for the protection and survival of raptors that may be vulnerable and in decline. This is the first book to show in detail the actual parts of a bird, mammal or other animal that you are likely to find in a garden, woodland or beneath a raptor roost. As more people take an interest in raptors and watch species such as peregrines via webcams and through watch groups, there is greater opportunity for finding prey remains. This book provides the first and most important step in identifying a prey species.

Really Rewarding Rewards: Strategic Licensing in Long-Term Healthy Food Consumption

2021 ◽  
Author(s):  
Rishika Rishika ◽  
Sven Feurer ◽  
Kelly L Haws
Keyword(s):  
Decision Making ◽  
Experimental Study ◽  
Consumption Patterns ◽  
Driving Mechanism ◽  
Policy Makers ◽  
Calorie Consumption ◽  
Food Purchases ◽  
Related Aspect ◽  
Over Time

Abstract Licensing is a well-documented form of justifying individual indulgent choices, but less is known about how licensing affects food decision-making patterns over time. Accordingly, we examine whether consumers incorporate licensing strategically and deliberately in their long-term consumption patterns and identify reward programs as a context in which strategic licensing is likely to occur. We propose that members with lower-calorie consumption patterns strategically indulge more on reward purchase occasions, and that forethought is required for such an effect to occur. A longitudinal study analyzing 272,677 real food purchases made by 7,828 consumers over a 14-month period provides striking evidence of our key proposition. An exploration of the inter-purchase time-related aspect of purchase acceleration suggests that forethought on behalf of consumers is necessary for strategic licensing to occur. A subsequent experimental study (N = 605) comprising five consecutive choice occasions provides additional evidence of forethought by demonstrating that strategic licensing occurs only when expected (but not windfall reward) occasions are involved, and by showing that anticipated negative affect for not indulging is the driving mechanism. We conclude with a discussion of the implications of our results for consumers, managers, and public policy makers.

EXPERIMENTAL STUDY OF ENERGY DISSIPATION IN A SINGLE STEP CONDITION OVER A BROAD CRESTED WEIR

2021 ◽  
Vol 5 (2) ◽  
pp. 155-165
Author(s):  
Bashir Tanimu ◽  
Aliyu Bamaiyi Usman ◽  
Al-Amin Danladi Bello ◽  
Sulaiman Jamilu Abdullahi
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Flow Rate ◽  
Research Study ◽  
Flow Characteristics ◽  
Single Step ◽  
Transition Flow ◽  
Experimental Performance ◽  
Empirical Relations ◽  
Model Equations

This research study the experimental performance of broad-crested weir with single-step by introducing U/S and D/S round-nose and  analysing the parameters that have effect on the shape of the step and their effects on the flow characteristics and energy dissipation (E%) downstream (D/S) of the weir. Furthermore, empirical relations for E% and flow rate due to the influencing factors were derived. The results showed that the weir model with  = 1.000 gives a higher E% in comparison with other weir models. Flow regimes were observed i.e nappe flow for small discharges, transition flow for intermediate discharges and skimming flow for higher discharges. Two model equations were obtained, the first to dteremine the flow rate over the weir models and the second relation to estimate E% in terms of, and Froude number. The model () can be used in the design of prototype weirs in terms of energy dissipation

Risk-Reduction Processes in Repetitive Consumer Behavior

1968 ◽  
Vol 5 (3) ◽  
pp. 307-310 ◽  
Author(s):  
Jagdish N. Sheth ◽  
M. Venkatesan
Keyword(s):  
Decision Making ◽  
Experimental Study ◽  
Risk Reduction ◽  
Brand Loyalty ◽  
Information Seeking ◽  
Perceived Risk ◽  
Risk Groups ◽  
Consumer Decision Making ◽  
Reduction Processes ◽  
Over Time

This experimental study of consumer decision making over time explored risk-reduction processes of information seeking, prepurchase deliberation, and brand loyalty. Perceived risk was manipulated by creating low-risk and high-risk groups. The task was to choose among brands of hair spray. Results showed that information seeking and prepurchase deliberation declined over time and brand loyalty increased over time.

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