scholarly journals Marine subsidies change short-term foraging activity and habitat utilization of terrestrial lizards

2017 ◽  
Vol 7 (24) ◽  
pp. 10701-10709 ◽  
Author(s):  
Heather V. Kenny ◽  
Amber N. Wright ◽  
Jonah Piovia-Scott ◽  
Louie H. Yang ◽  
David A. Spiller ◽  
...  
2014 ◽  
Vol 92 (11) ◽  
pp. 915-925 ◽  
Author(s):  
Soizic Le Saout ◽  
Sophie Padié ◽  
Simon Chamaillé-Jammes ◽  
Simon Chollet ◽  
Steve Côté ◽  
...  

Hunting is commonly used to reduce overabundant deer populations that are of socioeconomic and ecological concerns. Recently, it has been suggested that “hunting for fear” might help maximize nonconsumptive effects of hunting and their cascading impacts. We investigated how a predator-free black-tailed deer (Odocoileus hemionus sitkensis Merriam, 1898) population introduced to the Haida Gwaii archipelago (Canada) responded to short-term hunting for fear. We conducted a hunt that minimized killing and maximized scaring on an island where some deer were marked. Between control and hunted sites, we compared deer use of bait stations and of shoreline areas (i.e., an open and risky area that provided marine subsidies). We also compared the browsing pressure and growth of two grasses and two shrubs. Hunting for fear had no effect on the overall use of bait stations and shorelines. However, in the area exposed to hunting, unmarked deer, which were assumed to be less tolerant of human disturbance, avoided bait stations at the outset of hunting. We concluded that individuals perceive and respond to risk differently. Furthermore, two of the four plant species were less likely to be browsed and had better growth in the experimental area than in the control area, suggesting an indirect effect of hunting on plants mediated by deer behaviour.


Author(s):  
Juan A. Arce ◽  
Fernando Alonso ◽  
Antonio Camacho ◽  
Eugenio Rico

Crayfish are among the largest aquatic macroinvertebrates in rivers and streams. Their trophic ecology is important for the understanding of the functioning of benthic communities. This is relevant in key areas, such as headwaters, as they partly condition the processes occurring downstream. To shed light on the effects of native white-clawed crayfish, Austropotamobius pallipes, on local macroinvertebrate assemblages from running headwaters, a three-month mesocosm-based field study was designed. Collection and subsequent analysis of benthic samples under different crayfish density levels yielded a set of metrics indicative of short-term impacts at general and taxonomic scales. Neither significant positive nor negative effects on the community were evident in terms of richness, diversity, dominance and biomass. A combination of highly patched distributions of macroinvertebrates along with a weak impact of crayfish foraging activity is considered to explain this lack of effects. Only temporal changes associated with particular biological cycles appeared for some of the main taxa. Based on the results, we are not able to determine whether the white-clawed crayfish perceptibly disturbs the structure and composition of the local macroinvertebrate assemblages in the short-term. Thus, its use in future restocking projects is supported.


2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.


Author(s):  
M. O. Magnusson ◽  
D. G. Osborne ◽  
T. Shimoji ◽  
W. S. Kiser ◽  
W. A. Hawk

Short term experimental and clinical preservation of kidneys is presently best accomplished by hypothermic continuous pulsatile perfusion with cryoprecipitated and millipore filtered plasma. This study was undertaken to observe ultrastructural changes occurring during 24-hour preservation using the above mentioned method.A kidney was removed through a midline incision from healthy mongrel dogs under pentobarbital anesthesia. The kidneys were flushed immediately after removal with chilled electrolyte solution and placed on a LI-400 preservation system and perfused at 8-10°C. Serial kidney biopsies were obtained at 0-½-1-2-4-8-16 and 24 hours of preservation. All biopsies were prepared for electron microscopy. At the end of the preservation period the kidneys were autografted.


Author(s):  
D.N. Collins ◽  
J.N. Turner ◽  
K.O. Brosch ◽  
R.F. Seegal

Polychlorinated biphenyls (PCBs) are a ubiquitous class of environmental pollutants with toxic and hepatocellular effects, including accumulation of fat, proliferated smooth endoplasmic recticulum (SER), and concentric membrane arrays (CMAs) (1-3). The CMAs appear to be a membrane storage and degeneration organelle composed of a large number of concentric membrane layers usually surrounding one or more lipid droplets often with internalized membrane fragments (3). The present study documents liver alteration after a short term single dose exposure to PCBs with high chlorine content, and correlates them with reported animal weights and central nervous system (CNS) measures. In the brain PCB congeners were concentrated in particular regions (4) while catecholamine concentrations were decreased (4-6). Urinary levels of homovanillic acid a dopamine metabolite were evaluated (7).Wistar rats were gavaged with corn oil (6 controls), or with a 1:1 mixture of Aroclor 1254 and 1260 in corn oil at 500 or 1000 mg total PCB/kg (6 at each level).


Author(s):  
S.S. Poolsawat ◽  
C.A. Huerta ◽  
S.TY. Lae ◽  
G.A. Miranda

Introduction. Experimental induction of altered histology by chemical toxins is of particular importance if its outcome resembles histopathological phenomena. Hepatotoxic drugs and chemicals are agents that can be converted by the liver into various metabolites which consequently evoke toxic responses. Very often, these drugs are intentionally administered to resolve an illness unrelated to liver function. Because of hepatic detoxification, the resulting metabolites are suggested to be integrated into the macromolecular processes of liver function and cause an array of cellular and tissue alterations, such as increased cytoplasmic lysis, centrilobular and localized necroses, chronic inflammation and “foam cell” proliferation of the hepatic sinusoids (1-4).Most experimentally drug-induced toxicity studies have concentrated primarily on the hepatic response, frequently overlooking other physiological phenomena which are directly related to liver function. Categorically, many studies have been short-term effect investigations which seldom have followed up the complications to other tissues and organs when the liver has failed to function normally.


Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.


2008 ◽  
Vol 45 ◽  
pp. 147-160 ◽  
Author(s):  
Jörg Schaber ◽  
Edda Klipp

Volume is a highly regulated property of cells, because it critically affects intracellular concentration. In the present chapter, we focus on the short-term volume regulation in yeast as a consequence of a shift in extracellular osmotic conditions. We review a basic thermodynamic framework to model volume and solute flows. In addition, we try to select a model for turgor, which is an important hydrodynamic property, especially in walled cells. Finally, we demonstrate the validity of the presented approach by fitting the dynamic model to a time course of volume change upon osmotic shock in yeast.


1999 ◽  
Vol 97 (3) ◽  
pp. 319 ◽  
Author(s):  
D.A. DUPREZ ◽  
M.L. DE BUYZERE ◽  
B. DRIEGHE ◽  
F. VANHAVERBEKE ◽  
Y. TAES ◽  
...  

2020 ◽  
Vol 134 (4) ◽  
pp. 389-401
Author(s):  
Carla El-Mallah ◽  
Omar Obeid

Abstract Obesity and increased body adiposity have been alarmingly increasing over the past decades and have been linked to a rise in food intake. Many dietary restrictive approaches aiming at reducing weight have resulted in contradictory results. Additionally, some policies to reduce sugar or fat intake were not able to decrease the surge of obesity. This suggests that food intake is controlled by a physiological mechanism and that any behavioural change only leads to a short-term success. Several hypotheses have been postulated, and many of them have been rejected due to some limitations and exceptions. The present review aims at presenting a new theory behind the regulation of energy intake, therefore providing an eye-opening field for energy balance and a potential strategy for obesity management.


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