bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rate of passage of digesta through the alimentary tract of southern elephant seals (Mirounga leonina) (Carnivora: Phocidae)
Authors: Krockenberger M. B. , Bryden M. M. 
Published: March 2009

The inert markers chromium‐EDTA (liquid phase marker) and ytterbium nitrate (solid phase marker) were added to the food of three southern elephant seals in Taronga Zoo, Sydney, in a series of nine trials. The enclosures were checked at 15 to 30 minute intervals for up to 60 hours after dosing, and all faeces voided on land were collected (91 samples). Marker concentrations in faecal dry matter were determined and mean retention times calculated from the concentration‐time curves.The faeces were soft to semiliquid, with mean water content of 58% (range 24–80%). The marker concentration curves indicated a rapid rate of food transit through the gastro‐intestinal tract in elephant seals compared with other carnivores. The mean time between dosing and first recovery of marker (Initial Recovery Time) was nine hours. This was significantly longer than the figure of 4.8 hours for northern elephant seals reported previously, and possible reasons for the differences are discussed. Mean Retention Time, a better index of rate of passage of ingesta, was 13 hours for the three southern elephant seals. This compares with times of 22 hours for the dog, 15 hours for the raccoon, and 13 hours for the cat, all carnivores with much shorter gastrointestinal tracts, both absolutely and relative to body size, than the southern elephant seal.It is suggested that the very long small intestine may be an adaptation to foraging at depth, combined with long periods of submergence and the need to ingest large amounts of food when the animal is at sea continuously for weeks or months.
The temperature tolerances ofTetraclita squamosa(Crustacea: Cirripedia) andSeptifer virgatus(Bivalvia: Mytilidae) on a sub‐tropical rocky shore in Hong Kong
Authors: Liu J. H. , Morton Brian 
Published: March 2009

Mid‐tidal levels on Hong Kong's exposed shores are dominated by sessile barnacles (Tetraclita squamosa) and mussels (Septifer virgatus).Such shores experience dramatic elevations in air and rock temperatures in mid summer that have been causally linked to mortalities of these species.Tetraclita squamosaandS. virgatushad lower body temperatures relative to their rock substratum. Mussel inhabitants of high‐ and low‐zoned pools were in temperature equilibrium with contained water. On the rocks, body temperatures ofT. squamosawere higher than those ofS. virgatus.Middle shore individuals had higher body temperatures than lower shore ones. Individuals in the sun had higher body temperatures than those in the shade. Factors possibly affecting body temperature are orientation to the incident sunlight, height on the shore and the contact area between the individual and the substratum.Mean heat coma temperature (HCT) values for submergedSeptifer virgatuswere 45.0d̀C and 44.5d̀C for individuals of between 10‐20mm and 30‐50mm shell length, respectively. Mean median lethal temperature (LT50) values for submergedS. virgatuswere the same for both size classes (47.0d̀C). A longer exposure in air resulted in a lower LT50value; a shorter exposure in air resulted in a higher LT50value.Water content ofSeptifer virgatuswas between 89.21–90.26%, i.e. including the water from the mantle cavity. In air temperatures of between 30–32d̀C and after long periods of exposure,Septifer virgatusshowed significant water loss, i.e. of between 13.87‐15.52% body water content. In air temperatures of between 33–36d̀C and after relatively short exposures,Septifer virgatusshowed small water losses, i.e. between 1.92‐5.74% body water content.On Hong Kong's exposed rocky shores, sessile components of the middle shore environment are thermally stressed in summer when low tides occur in the afternoon in combination with periods of cloudless sunny days and when rock temperatures may climb to ≅ 50d̀C through solar insolation. Lower‐zoned individuals and high‐zoned pool residents are buffered from the adverse effects of such environmental extremes. Mortality occurred mainly in the sun‐exposed shore populations of bothTetraclita squamosaandSeptifer virgatusand is particularly evident when the above combination of climatic and tidal factors first occurs in July.
Identifying the effects of history on adaptation: origins of different sand‐diving techniques in lizards
Authors: Arnold E. N. 
Published: March 2009

The effects of previous history on adaptation can be studied in situations where several taxa have been independently exposed to a well‐specified problem posed by their selective regimes. This approach was applied to the ways surface‐dwelling dune lizards dive rapidly into loose sand when evading predators. Lacertids of the genus Meroles use all limbs and serpentine body and tail movements, behaviour which arose directly in the context of predator evasion in sandy habitats. The agamids, Phrynocephalus and Agama etoshae employ lateral body oscillations and descend vertically, an aberrant method resulting from previous evolution of a blunt snout. The scincid, Scincus and gerrhosaurid, Angolosaurus, both use high amplitude sinusoidal movements of the body and tail, which apparently evolved in a common ancestor of these taxa long before being co‐opted to use in sand. In contrast, the scincid, Mabuya acutilabris, holds the body straight, a method that probably originated in the context of concealment at the end of activity.In the phrynosomatid, Uma, the head oscillates up to 60 times per second, the forelimbs are folded back and hindlimb thrust is supplemented by scales on the upper arms acting like ratchets. Some components of this method originated in the context of slow concealment in firm substrata at the end of activity periods, a basic pattern later co‐opted for rapid diving in compact sand with modification of the snout to form a drill. Finally, this elaborated mechanism was transferred to loose sand with further behavioural and morphological change. Rapid sand burial by Phrynosoma species has the same origin as that in Uma but, like Phrynocephalus, includes a strong vertical component. It too is associated with a blunt snout which, however, arose after initial burial behaviour developed, not before.These results suggest that, once related lineages have diverged, differences may still accumulate even in similar situations. Sand diving also exhibits striking cases of convergence and provides an example of how function can be used to polarize characters, suggest the situations in which derived states arose and indicate their likely order of change.
The population dynamics and reproductive cycle of Septifer virgatus (Bivalvia: Mytilidae) on an exposed rocky shore in Hong Kong
Authors: Morton Brian 
Published: March 2009

Exposed rocky shores in Hong Kong are dominated at mid‐tidal levels by a broad band of the mytilid Septifer virgatus. A 48‐month study of a population inhabiting the shores at Cape d'Aguilar has been undertaken. The species matures at a shell length of ≅ 15 mm, about one year after recruitment. Septifer virgatus is dioecious with a slight, but insignificant, female bias overall. There is, however, a significant juvenile male bias. Generally, most adult individuals remain mature year round, although spawning is limited to two periods in spring (February to March) and autumn (September to December) with subsequent recruitment into the adult population. The species lives for ≅ 4–5 years, although older individuals, possibly up to 12 years of age and with a maximum recorded shell length of 65 mm, occur as solitary individuals lower down the shore. Mortality in winter mainly affects newly recruited juveniles. A heavy mortality of adults in summer is thought to be related to high rock temperatures at midday (≅ 50°C), concurrent with low spring tides.The life‐history tactics and sexual strategy of Septifer virgatus can be correlated with seasonal changes in hydrography. There are a number of similarities with other local mytilids, notably the dioecious condition and the bimodal pattern of spawning and recruitment. Such similarities are discussed in relation to the habitats occupied by these species.
Influence of the abundance of food resources on the feeding habits of the red fox, Vulpes vulpes, in western Switzerland
Authors: FERRARI N. 
Published: March 2009

J.‐M. WEBERThe influence of food abundance on red fox feeding habits was studied in the Swiss Jura Mountains between November 1990 and February 1992, during a low density period in the water vole population cycle. Six food categories–water voles, small mammals, domestic stock, earthworms, wild fruits and exploitable scraps–were censused during the present research and their seasonal abundances were estimated in fixed plots. Fox scats were collected and analysed at regular monthly intervals.The diet of foxes was found to be correlated with seasonal food supply. A positive significant correlation between seasonal abundances and relative proportions in the diet was found for food categories showing a clear seasonality (earthworms, wild fruits and exploitable scraps), whereas no correlation was recorded for the other food resources. Diet composition observed in the present study was compared with that recorded in the same study area between 1988 and 1990 by Weber & Aubry (1993), when water voles were very common and accounted for more than 50% of the diet. A significant change was recorded in red fox feeding habits: the most important aspects of this modification of the diet was the decrease in water vole importance accompanied by the increase in the frequency of occurrence of other food categories, such as wild fruits and scavengeable items.
The passage of digesta, particle size, and in vitro fermentation rate in the three‐toed sloth Bradypus tridactylus (Edentata: Bradypodidae)
Authors: Foley W. J. , Engelhardt W. V. , Charles‐Dominique P. 
Published: March 2009

The digestive physiology of six three‐toed sloths (Bradypus tridactylus) fed exclusively on Cecropia palmata foliage was studied. The mass of digesta in the gut was between 17 and 37% of body mass. This was between 133 and 282% of that expected in an animal of this size, based on published allometric equations. The concentration of total short chain fatty acids in the stomach was similar to that in the fermentative regions of other foregut fermenting herbivores but the rate of fermentation measured in vitro was very slow (6–12 mmol.l‐1.h‐1) and substantially lower than that observed using similar techniques in other small foregut fermenters.The overall (dose to excretion) mean retention time of particulate and solute digesta markers was about 150 h. Most of this (73%) occurred in the stomach but a substantial proportion (17%) could be attributed to the storage of faeces in the rectum.The slow rate of passage of digesta through the gut together with the slow rate of fermentation in the stomach is not typical of small foregut fermenting herbivores. However, such a pattern is feasible in Bradypus tridactylus because of the large volume of digesta retained in the gut and the very low metabolic rate of these mammals.
Temporal and spatial patterns in blue duikers Philatomba monticola and red duikers Cephalophus natalensis
Authors: Bowland A. E. , Perrin M. R. 
Published: March 2009

Forest duikers spend a large proportion of the day engaged in sedentary behaviour. Both species were most active shortly after dawn and just before dusk and were relatively more active in habitats of higher quality. Though home‐range boundaries were dynamic (changing slightly during the year), core areas were permanent and remained fixed.Blue duikers showed exclusive family home ranges with no overlap between neighbours, for this species home range and territory are synonymous. Red duiker home‐range overlap varied greatly (up to 100% in some cases) indicating the absence of territoriality. Core areas in the home range of both duiker species were usually associated with bedsites. In blue duiker, home ranges and core areas were fixed all year with no overlap between neighbours, while home ranges and core areas of red duikers overlapped extensively. Temporal separation in red duikers is suggested between some individuals and not others.
Coefficients of digestibility and nutritional values of geophytes and tubers eaten by southern African mole‐rats (Rodentia: Bathyergidae)
Authors: Bennett N. C. , Jarvis J. U. M. 
Published: March 2009

Subterranean rodents have high energy requirements when they are excavating their burrows. This study investigates the energy available to, and the efficiency with which it can be extracted by, four species of bathyergid mole‐rats fed natural diets ranging from the underground storage organs of geophytes to grass roots and leaves.The digestibility coefficients of geophytes ranged from 53% for the fibrous tuber of the gemsbok cucumber to 95–7% for corms and bulbs. One species, Bathyergus suillus whose diet consists of over 80% grass, had a digestibility coefficient of 87% on an all grass diet.All species had similar coefficients of digestibility of > 90% when fed on a uniform diet of sweet potato.Bulbs and corms had a low fibre content (3–3–4%), high calorific value (15–16kJ/g) and high digestibility coefficients (95–7–96%) and on this diet the mole‐rats maintained their body mass. Food of lower digestibility tended to have a high fibre content (8–2–45%) and, with the exception of B. suillus, although the mole‐rats consumed a greater quantity of food, they lost mass. The sweet potato had a low fibre content (4–1 %) but was energetically very similar to bulbs and corms (15–5 kJ/g).Geophytes which have low fibre contents are generally small (1–20 g), whereas geophytes with high fibre contents are much larger (30–2000 g) and often occur in more arid zones.
AKAP10 (I646V) functional polymorphism predicts heart rate and heart rate variability in apparently healthy, middle‐aged European‐Americans
Authors: Neumann Serina A. , Tingley Whittemore G. , Conklin Bruce R. , Shrader Catherine J. , Peet Eloise , Muldoon Matthew F. , Jennings J. Richard , Ferrell Robert E. , Manuck Stephen B. 
Published: March 2009

AbstractPrevious evidence suggests that the dual‐specific A kinase‐anchoring protein 2 functional polymorphism (AKAP10 (A/G) I646V) influences heart rate (HR) and heart rate variability (HRV) in mice and humans (N=122) with cardiovascular disease. Here, we asked whether this AKAP10 variant predicts HR and HRV in a large sample of healthy humans. Resting HR and short‐term time and frequency domain measures of HRV (5 min during paced and unpaced respiration conditions) were assessed in a U.S. community sample (N=1,033) of generally healthy men and women (age 30–54) of European ancestry. Each person was genotyped for the AKAP10 variant. As with previous work, the AKAP10 Val allele predicted greater resting HR (Paced p<.01; Unpaced p<.03) and diminished HRV (Paced ps <.05) suggesting that this variant may modulate the sensitivity of cardiac pacemaker cells to autonomic inputs, possibly conferring risk for arrhythmias and sudden cardiac death.
Pupillometric measures of attentional allocation to target and mask processing on the backward masking task in schizophrenia
Authors: Granholm Eric , Fish Scott C. , Verney Steven P. 
Published: March 2009

AbstractAllocation of attentional resources during early visual processing was investigated in schizophrenia. Pupillary responses were recorded during a backward masking task as an index of resource allocation in schizophrenia patients (n=51) and nonpsychiatric controls (n=51). Two time‐linked components of pupillary response waveforms appeared to differentially index resource allocation to targets versus masks. Two patient subgroups were identified: One with normal overall pupillary responses (resource allocation), but greater allocation on mask relative to target components, and another with abnormally small overall pupillary responses and similar allocation between target and mask components. Thus, misallocation of resources to masks contributed to masking deficits in one subgroup, whereas reduced resource allocation contributed to deficits in the other. The nature of resource‐related deficits can vary across schizophrenia subgroups.
Serial or parallel processing in dual tasks: What is more effortful?
Authors: Lehle Carola , Steinhauser Marco , Hübner Ronald 
Published: March 2009

AbstractRecent studies indicate that dual tasks can be performed with a serial or parallel strategy and that the parallel strategy is preferred even if this implies performance costs. The present study investigates the hypothesis that parallel processing is favored because it requires less mental effort compared to serial processing. A serial or parallel processing strategy was induced in a sample of 28 healthy participants. As measures of mental effort, we used a rating as well as heart rate (HR) and electrodermal activity. Parallel processing again showed performance costs relative to serial, whereas serial processing was judged as more effortful. Also tonic HR and phasic HR deceleration were increased with a serial strategy. Thus the preference for a parallel strategy in dual tasks likely reflects a compromise between optimizing performance and minimizing the amount of mental effort. This aspect is neglected in current dual task accounts so far.
Cognitive processes facilitated by contextual cueing: Evidence from event‐related brain potentials
Authors: Schankin Andrea , Schubö Anna 
Published: March 2009

AbstractFinding a target in repeated search displays is faster than finding the same target in novel ones (contextual cueing). It is assumed that the visual context (the arrangement of the distracting objects) is used to guide attention efficiently to the target location. Alternatively, other factors, e.g., facilitation in early visual processing or in response selection, may play a role as well. In a contextual cueing experiment, participant's electrophysiological brain activity was recorded. Participants identified the target faster and more accurately in repeatedly presented displays. In this condition, the N2pc, a component reflecting the allocation of visual‐spatial attention, was enhanced, indicating that attention was allocated more efficiently to those targets. However, also response‐related processes, reflected by the LRP, were facilitated, indicating that guidance of attention cannot account for the entire contextual cueing benefit.
Adult neural stem/progenitor cells reduce NMDA‐induced excitotoxicity via the novel neuroprotective peptide pentinin
Authors: Faijerson Jonas , Thorsell Annika , Strandberg Joakim , Hanse Eric , Sandberg Mats , Eriksson Peter S. , Tinsley Rogan B. 
Published: March 2009

J. Neurochem. (2009) 109, 858–866.AbstractAlthough the potential of adult neural stem cells to repair damage via cell replacement has been widely reported, the ability of endogenous stem cells to positively modulate damage is less well studied. We investigated whether medium conditioned by adult hippocampal stem/progenitor cells altered the extent of excitotoxic cell death in hippocampal slice cultures. Conditioned medium significantly reduced cell death following 24 h of exposure to 10 μM NMDA. Neuroprotection was greater in the dentate gyrus, a region neighboring the subgranular zone where stem/progenitor cells reside compared with pyramidal cells of the cornis ammonis. Using mass spectrometric analysis of the conditioned medium, we identified a pentameric peptide fragment that corresponded to residues 26–30 of the insulin B chain which we termed ‘pentinin’. The peptide is a putative breakdown product of insulin, a constituent of the culture medium, and may be produced by insulin‐degrading enzyme, an enzyme expressed by the stem/progenitor cells. In the presence of 100 pM of synthetic pentinin, the number of mature and immature neurons killed by NMDA‐induced toxicity was significantly reduced in the dentate gyrus. These data suggest that progenitors in the subgranular zone may convert exogenous insulin into a peptide capable of protecting neighboring neurons from excitotoxic injury.
Glutamate‐dependent transcriptional control in Bergmann glia: Sox10 as a repressor
Authors: Cruz‐Solis Irma , Zepeda Rossana C. , Ortiz Sharon , Aguilera José , López‐Bayghen Esther , Ortega Arturo 
Published: March 2009

J. Neurochem. (2009) 109, 899–910.AbstractGlutamate (Glu) is the major excitatory transmitter in the vertebrate brain. Ligand‐gated and G protein‐coupled Glu receptors present in glial cells are presumably involved in neuronal function. Activation of Bergmann glial Glu receptors triggers a membrane to nuclei signaling cascade that regulates gene expression at the transcriptional and translational levels. Sry‐related high‐mobility group box (Sox10), a member of the conserved high‐mobility group box transcription factor family is expressed in neural crest stem cells and in a subset of neural crest‐derived lineages that include glial, but not neuronal cells. To gain insight into the role of Sox10 in Bergmann glial cells, we explored its expression and regulation. We demonstrate herein that Sox10 is expressed in Bergmann glial cells and that its DNA binding activity, mRNA, and protein levels as well as its transcriptional behavior augments upon the activation of metabotropic Glu receptors. Increase in Sox10–DNA complexes and Sox10 mRNA and protein levels were found upon exposure to Glu. Over‐expression of Sox10 leads to transcriptional repression in reporter gene assays and in one of its target genes: the chick kainate binding protein gene. These findings add a new perspective into glial glutamatergic signaling and suggest the participation of Sox10 in cerebellar glutamatergic transactions.
The brain 5‐HT4receptor binding is down‐regulated in the Flinders Sensitive Line depression model and in response to paroxetine administration
Authors: Licht Cecilie L. , Marcussen Anders B. , Wegener Gregers , Overstreet David H. , Aznar Susana , Knudsen Gitte M. 
Published: March 2009

AbstractThe 5‐hydroxytryptamine (5‐HT4) receptor may be implicated in depression and is a new potential target for antidepressant treatment. We have investigated the brain 5‐HT4receptor [3H]SB207145 binding in the Flinders Sensitive Line rat depression model by quantitative receptor autoradiography, and related this to 5‐HT transporter (S)‐[N‐methyl‐3H]citalopram binding. We also determined the regulation of 5‐HT4receptor binding by 1, 14, and 21 days of paroxetine administration and subchronic 5‐HT depletion, and compared this with changes in 5‐HT2Areceptor [3H]MDL100907 binding. In the Flinders Sensitive Line, the 5‐HT4receptor and 5‐HT transporter binding were decreased in the dorsal and ventral hippocampus, and the changes in binding were directly correlated within the dorsal hippocampus. Chronic but not acute paroxetine administration caused a 16–47% down‐regulation of 5‐HT4receptor binding in all regions evaluated including the basal ganglia and hippocampus, while 5‐HT depletion increased the 5‐HT4receptor binding in the dorsal hippocampus, hypothalamus, and lateral globus pallidus. In comparison, the 5‐HT2Areceptor binding was decreased in the frontal and cingulate cortices after chronic paroxetine administration, and markedly reduced in several regions after 5‐HT depletion. Thus, the 5‐HT4receptor binding was decreased in the Flinders Sensitive Line depression model and in response to chronic paroxetine administration.