Quatic Foraging in Garter Snakes: a Comparison of Specialists and Generalists

Behaviour ◽  
1983 ◽  
Vol 86 (1-2) ◽  
pp. 1-30 ◽  
Author(s):  
Hugh Drummond
Keyword(s):  
Short Distance ◽  
Water Surface ◽  
Search Time ◽  
Open Water ◽  
Garter Snakes ◽  
Nerodia Sipedon ◽  
Long Distance ◽  
Underwater Vision ◽  
Visual Accommodation ◽  
Made In

AbstractTo examine the assumption, underlying much ecological theory, that a "Jack-of-all-trades is master of none", a comparison was made of the aquatic predation of four colubrid snakes, two aquatic specialists (Thamnophis couchi, T. melanogaster) and two terrestrial-aquatic generalists (T. sirtalis, and T. elegans). Observations were made in the field, then juvenile snakes were compared under controlled laboratory conditions. The specialists and generalists had qualitatively different foraging repertoires. The specialists made lengthy dives, crawled slowly on the underwater substrate and made long-distance underwater responses to prey: orientation, approach, pursuit, and frontal attack. The generalists dived briefly, with rapid serpentine locomotion, or searched "terrestrially" by wandering along the shoreline and snatching prey from the water surface. Underwater, the generalists' only prey-directed response was sudden short-distance attack, and they appeared to rely on chance encounters with prey. There were significant differences between the two pairs. In comparison with the generalists, the specialists 1) captured more fish, 2) spent more time on aquatic search, 3) spent more aquatic search time diving, 4) spent more diving time on the underwater substrate, 5) made more attacks in every category of search in open water, and 6) attacked underwater from a greater distance. Significant differences were not found in attack frequencies in those search categories where underwater vision is probably unimportant (aerial attacks and attacks in underwater crevices), nor in aerial attack distances. The specialists' behavioral superiority in respect of their specialization supports the "Jack-of-all-trades" assumption. The observations suggest that this superiority is associated with superior underwater visual acuity (which may be due to superior visual accommodation). The generalists' principal underwater searching technique (serpentine diving) appears to be energetically costly, and may only be profitable when aquatic prey are especially vulnerable. Nerodia sipedon, member of a genus that is closely related to Thamnophis but more aquatic, had a foraging repertoire qualitatively similar to that of the generalists. The similarity may be associated with N. sipedon's nocturnal habits and presumed reliance on non-visual prey cues.

scholarly journals No general shift in spring migration phenology by eastern North American birds since 1970

2021 ◽  
Author(s):  
André Desrochers ◽  
Andra Florea ◽  
Pierre-Alexandre Dumas
Keyword(s):  
Short Distance ◽  
Species Abundance ◽  
Open Water ◽  
Early Spring ◽  
Spring Migration ◽  
The Arctic ◽  
Long Distance ◽  
Arrival Dates ◽  
Migration Phenology ◽  
First Arrival

We studied the phenology of spring bird migration from eBird and ÉPOQ checklist programs South of 49°N in the province of Quebec, Canada, between 1970 and 2020. 152 species were grouped into Arctic, long-distance, and short-distance migrants. Among those species, 75 significantly changed their migration dates, after accounting for temporal variability in observation effort, species abundance, and latitude. But in contrast to most studies on the subject, we found no general advance in spring migration dates, with 36 species advancing and 39 species delaying their migration. Several early-migrant species associated to open water advanced their spring migration, possibly due to decreasing early-spring ice cover in the Great Lakes and the St-Lawrence river since 1970. Arctic breeders and short-distance migrants advanced their first arrival dates more than long-distance migrants not breeding in the arctic. However, there was no difference among migrant groups when median arrival dates were considered. We conclude that general claims about advances in spring migration dates in eastern North America are misleading due to large taxonomic variation.

Loss of sleep or loss of dark?

2018 ◽  
Author(s):  
Richard G. Stevens
Keyword(s):  
Mood Disorders ◽  
Deep Sea ◽  
Short Distance ◽  
Water Surface ◽  
Ocean Floor ◽  
Physiological Adaptation ◽  
Poor Sleep ◽  
Short Period ◽  
The World ◽  
Night And Day

Before electricity, night was something akin to the deep sea: just as we could not descend much below the water surface, we also could not investigate the night for more than a short distance, and for a short period of time. Things changed with two inventions: the Bathysphere to plumb the ocean floor, and electricity to light the night for sustained exploration. Exploration led to dominance, and night has become indistinguishable from day in many parts of the world. The benefits of electric light are myriad, but so too are the possible detriments of loss of dark at night, including poor sleep, obesity, diabetes, cancer, and mood disorders. Our primordial physiological adaptation to the night and day cycle is being flummoxed by the maladaptive signals coming from electric lighting around the clock. The topic of sleep and health has finally attained scientific respect, but dark and health is not yet fully appreciated.

scholarly journals K → μ+μ− as a clean probe of short-distance physics

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Avital Dery ◽  
Mitrajyoti Ghosh ◽  
Yuval Grossman ◽  
Stefan Schacht
Keyword(s):  
Matrix Element ◽  
Standard Model ◽  
Short Distance ◽  
Time Dependent ◽  
Final States ◽  
Interference Effects ◽  
Fundamental Theory ◽  
Long Distance ◽  
Ckm Matrix ◽  
The Standard Model

Abstract The K → μ+μ− decay is often considered to be uninformative of fundamental theory parameters since the decay is polluted by long-distance hadronic effects. We demonstrate that, using very mild assumptions and utilizing time-dependent interference effects, ℬ(KS → μ+μ−)ℓ=0 can be experimentally determined without the need to separate the ℓ = 0 and ℓ = 1 final states. This quantity is very clean theoretically and can be used to test the Standard Model. In particular, it can be used to extract the CKM matrix element combination $$ \mid {V}_{ts}{V}_{td}\sin \left(\beta +{\beta}_s\right)\mid \approx \mid {A}^2{\lambda}^5\overline{\eta}\mid $$ ∣ V ts V td sin β + β s ∣ ≈ ∣ A 2 λ 5 η ¯ ∣ with hadronic uncertainties below 1%.

Advances in the study of the mechanochemical coupling of kinesin

2018 ◽  
Vol 32 (18) ◽  
pp. 1840001 ◽  
Author(s):  
Ming Li ◽  
Zhong-Can Ou-Yang ◽  
Yao-Gen Shu
Keyword(s):  
Molecular Dynamics ◽  
Single Molecule ◽  
Intracellular Transport ◽  
Coordination Mechanism ◽  
Personal Perspective ◽  
Long Distance ◽  
Future Studies ◽  
Mechanochemical Coupling ◽  
Dynamics Simulations ◽  
Made In

Kinesin is a two-headed linear motor for intracellular transport. It can walk a long distance in a hand-over-hand manner along the track before detaching (i.e., high processivity), and it consumes one ATP molecule for each step (i.e., tight mechanochemical coupling). The mechanisms of the coordination of its two heads and the mechanochemical coupling are the central issues of numerous researches. A few advances have been made in recent decades, thanks to the development of single-molecule technologies and molecular dynamics simulations. In this paper, we review some progress of the studies on the kinematics, energetics, coordination mechanism, mechanochemical mechanism of kinesin. We also present a personal perspective on the future studies of kinesin.

‘Scows, and barges, or other vessels of box model’: Comparative capital investment in the sailing scows of the Great Lakes of North America and in New Zealand

2018 ◽  
Vol 30 (1) ◽  
pp. 89-105
Author(s):  
Jay C. Martin
Keyword(s):  
New Zealand ◽  
North America ◽  
Great Lakes ◽  
Capital Investment ◽  
Open Water ◽  
Long Distance ◽  
American Frontier ◽  
International Context ◽  
The North ◽  
Hull Design

Boxy and with ‘unseaworthy form’, the sailing scow was not the most aesthetically pleasing of watercraft. Yet the durable hull design based upon European predecessors found a new home in North America where it proliferated on the Atlantic, Gulf, Pacific and Great Lakes coasts because of its practicality for largely unimproved waterways. Scows were widely used on the Great Lakes in the nineteenth century, moving beyond shallow waters and gaining a reputation for reliability in long-distance trade. Late in the century, the technology arrived in New Zealand, where it prospered in a niche market that combined open water voyages and shallow river, port, or beach loading and unloading. The Great Lakes scows presented an alternative for entry into ship ownership on the North American frontier. The development of the New Zealand scow confirmed these findings comparatively in an international context during the late nineteenth and early twentieth centuries.

scholarly journals Installasi Base Transceiver Station (BTS) untuk Jaringan Node B pada Operator Hutchison 3 Indonesia (H3I)

2015 ◽  
Vol 11 (1) ◽  
pp. 78
Author(s):  
Uzma Septima ◽  
Lince Markis
Keyword(s):  
Receive Signal ◽  
Network Operator ◽  
Long Distance ◽  
New Process ◽  
Station Base ◽  
Communication Links ◽  
Distance Communication ◽  
Base Transceiver Station ◽  
In Transit ◽  
Made In

Base Transceiver Station is a device used to connect mobile-phone or smartphone in order to make long-distance communication, although in doing the movement or in transit from one place to another. Installation Base Transceiver Station for Network Node B At the operator Hutchison 3 Indonesia is done to make the operator Hutchison 3 Indonesia signal received by the phone for the better and not dashed when the user performs long-distance communication links with conditions in performing the movement or in the course of one place to another. Methods beginning the process of physical installation of Base Transceiver Station for Node B network in the operator Hutchison 3 Indonesia and order all the Base Transceiver Station can live well after the battery is connected to a rectifier and the required accuracy when performing the installation Base Transceiver Station. Furthermore, the integration process or Commissioning of the Base Transceiver Station for Node B network operator Hutchison 3 Indonesia on this in order to actively and After Commissioning obtained Receive Signal Level sectoral antennas of -59 dBm which can emit a signal as far as 7 km to 8 km , after the new process or Pointing connection between this new Base Transceiver Station Base Transceiver Station with preexisting and Pointing between Siak new Base Transceiver Station Base Transceiver Station Perawang with Perawang Students who have a distance of 5 km Receive Signal level of -32.4 dBm made in accordance with a budget link provided operator Hutchison 3 Indonesia is -30 dBm to -40 dBm.

scholarly journals The impact of some morphological and motor characteristics in short distance running

2021 ◽  
Vol 11 (6) ◽  
pp. 109-119
Author(s):  
Q. Ramabaja ◽  
N. Rashiti ◽  
M. Shkodra ◽  
L. Ramadani
Keyword(s):  
Physical Education ◽  
Motor Skills ◽  
Short Distance ◽  
Morphological Development ◽  
Strong Impact ◽  
Distance Running ◽  
Anthropometric Parameters ◽  
Long Distance ◽  
Anthropometric Characteristics ◽  
The Impact

The knowledge of morphological development and their impact on motor skills in short-distance athletes should be one of the main concerns of athletics coaches, because any scientific research in the field of physical culture and sports is about proving the development and evaluation of anthropological characteristics which are responsible for achieving success in athletics. The purpose of this paper is to confirm the impact of some anthropometric characteristics in the execution of running speeds on short distances, specifically in running at 100, 200 and 400 meters to students aged 18 ± 6 years of the Faculty of Physical Education and Sports in Prishtina. The sample of this research has included a total of 60 students aged 18 years of the Faculty of Physical Education and Sports in Prishtina. The measurements were executed during September in the hall of the Faculty, while the 100, 200, and 400 meter runs in the stadium "Fadil Vokrri" Prishtina. The only condition that was used during the determination of the sample was: that the students are involved in regular physical education classes (and on the day of the measurement be healthy, without the flu, cold or other symptoms). The variables which are applied in this research have been 8 anthropometric variables and 3 motor-specific variables. The results obtained after their processing indicate that the impact of anthropometric variables is higher in running at 100, 200 and 400 meters. Short distance running and long distance running reduces the impact of anthropometric parameters whereas the influence of metabolic factors of energy production is increased.  These results were also confirmed using regression analysis, so that groups of predictors of anthropometric characteristics, specific motor skills that statistically significantly influenced each variable of individual criteria. The world records below the 10-second limit, in the 100 m, near the 9-meter limit, show not only the high level of sports, but also the strong impact on the growth, especially of strength indicators, speed-strength, explosive force, as main and applied motor skills in sports and athlete’s everyday life.

Sign in / Sign up

Export Citation Format

Share Document