| chromosomes of a cell line of dipodomys panamintinus (kangaroo rat). a banding and autoradiographic study. | the chromosomes of an established cell line of dipodomys panamintinus have been characterised in terms of their c, g and q banding patterns, and the distributions of silver grains in autoradiographs of chromosomes labelled in early or late s phase. no relationship could be established between c, g or q banding regions of chromosomes and a particular s phase time of replication of the dna in these banded regions. the implication of this result to the concept of heterochromatin is discussed. | 1975 | 49259 |
| binding of anti-nucleoside antibodies reveals different classes of dna in the chromosomes of the kangaroo rat (dipodomys ordii). | | 1977 | 70368 |
| influence of hypothalamic and ambient temperatures on sleep in kangaroo rats. | unanesthetized, unrestrained kangaroo rats (dipodomys) were studied to examine the changes in the frequency and duration of sleep states caused by long-term manipulations of hypothalamic temperature (thy) at a thermoneutral (30 degrees c) and a low (20 degrees c) ambient temperature (ta). a cold stimulus present in either the hypothalamus or the skin decreased both the total sleep time (tst) and the ratio of paradoxical sleep (ps) to tst. at a low ta, tst, but not the ps-to-tst ratio, was increa ... | 1979 | 223451 |
| some comparative aspects of renal adaptation to unilateral nephrectomy in white rats and kangaroo rats. | | 1975 | 236118 |
| water balance of merriam's kangaroo rat, dipodomys merriami, during cold exposure. | | 1975 | 237660 |
| an anatomical study of the brains of dipodomys (mammalia: rodentia: heteromyidae). | whole brains and nissl-stained serial sections of 3 species of kangaroo rat (dipodomys spectabilis, d. ordii, d. merriami) were compared for interspecific differences. neuroanatomical variations were conservative in nature. examination of the cerebellum revealed possible differences in locomotion and ecology. dipodomys ordii exhibited more neurological evidence for increased specialization of the hindlimbs, while d. merriami had the least differentiated cerebellar surface, thereby suggesting mor ... | 1979 | 507367 |
| similarity of satilite dna properties in the order rodentia. | we have characterized satellite dnas from 9 species of kangaroo rat (dipodomys) and have shown that the hs-alpha and hs-beta satellites, where present, are nearly identical in all species as to melting transition midpoint (tm), and density in neutral cscl, alkaline cscl, and cs(2)so(4)-ag(+) gradients. however, the ms satellites exist in two internally similar classes. the satellite dnas from three other rodents were characterized (densities listed are in neutral cscl). the pocket gopher, thomom ... | 1977 | 561953 |
| dipodomydectes americanus gen. et sp. n. (acari: hypoderidae) from the kangaroo rat. | | 1978 | 627953 |
| the endogenous stages of eimeria utahensis (protozoa: eimeriidae) in the kangaroo rat, dipodomys ordii. | the endogenous life cycle of eimeria utahensis is described from experimentally infected kangaroo rats, dipodomys ordii. the endogenous asexual cycle consisted of 4 generations of meronts. first-generation meronts were concentrated in the anterior third of the small intestine. the succeeding generations of meronts and the sexual stages were concentrated in the middle third of the small intestine. first-generation meronts had a mean diameter of 9.7 micrometer and contained 12 to 16 merozoites. se ... | 1978 | 627970 |
| the kangaroo rat as a model for type i decompression sickness. | this study involved 720 exposures of 70 kangaroo rats trapped in west texas and showed that decompression-induced tail biting in this animal provides a good animal model for marginal limb bends in man. that this phenomenon can be reversed by recompression and pathological examination of the tail both indicated that a similar mechanism is probably involved in kangaroo rats and humans. quantitatively, the most susceptible 20% of kangaroo rats can reproduce the no-stop decompression limits for man ... | 1978 | 734799 |
| fine structure of the heterochromatin of the kangaroo rat dipidomys ordii, and examination of the possible role of actin and myosin in heterochromatin condensation. | biochemical studies have suggested that some actin and myosin may be present in the nucleus. this raises the possibility that heterochromatin condensation might be the result of an actin-myosin rigour type complex. since atp dissociates actin and myosin, this possibility could be examined by determining the effect of atp on heterochromatin condensation. thin-section electron microscopy showed large amounts of condensed constitutive heterochromatin in the kidney nuclei and somewhat less in the li ... | 1976 | 823163 |
| response characteristics of cochlear nucleus neurons to vowel sounds. | most studies in auditory neurophysiology have utilized tonal stimuli to determine the coding properties of neurons in the cochlear nuclei. in this investigation of the kangaroo rat, cochlear nuclei, neuronal responses to vowel sounds, as well as tones, were studied. the vowel sounds, each about 40 msec in duration were: see article. five were linked together to form a 200 msec stimulus and various combinations of five vowel sounds provided us with 18 different stimuli. the results show that neur ... | 1977 | 835971 |
| kangaroo rat cochlea: qualitatively and quantitatively unique features. | | 1977 | 898499 |
| the pineal complex and its relationship to other epithalamic structures. | the pineal complex of rodents is made up of a pineal gland which developmentally always originates from the area between the habenular and posterior commissure and a pineal sac which is continuous with the choroid plexus of the third ventricle. at the light-microscopic level, this sac appears to be identical to the choroid plexus. the pineal sac abuts the deep and superficial pineal glands of the golden hamster. in the pet mouse, gerbil, kangaroo rat, and chinese hamster, the sac is contiguous w ... | 1977 | 899706 |
| an analysis of sandbathing and grooming in the kangaroo rat (dipodomys merriami). | the sandbathing and grooming behaviour of ten kangaroo rats (dipodomys merriami) were recorded on sand and woodchip substrates after periods of 0, 1, 5 and 10 days without sand. sandbathing is restricted to the sandy substrate. grooming occurs on both, but with a higher frequency on sand. increases in both grooming and sandbathing occur with increasing sand deprivation, but the temporal patterning does not change. d. merriami tends to alternate sandbathing components in contrast to other dipodom ... | 1976 | 937766 |
| [the ontogenesis of nycthemeral rhythm of the states of sleep in the kangaroo rat (potorous apicalis) (author's transl)]. | | 1976 | 996149 |
| s phase patterns of replication of different satellite dnas in three species of dipodomys (kangaroo rat). | | 1976 | 1011258 |
| investigation of the organization of mammalian chromosomes at the dna sequence level. | new developments in dna sequencing techniques permit rapid progress in the determination of both repetitious and single-copy mammalian sequences. three distinct families of highly repetitious satellite dna's from the kangaroo rat dipodomys ordii have been sequenced. with the ms satellite it was possible to show that the basic repeat sequence and its variants were arranged in a nonrandom order suggesting a hierarchy of repeats. the hs-alpha satellite from d. ordii was shown to resemble the guinea ... | 1976 | 1107072 |
| auditory systems of heteromyidae: postnatal development of the ear of dipodomys merriami. | serial histological sections of kangaroo rats of postnatal ages 0-, 3-, 7-, 10-, and 14-days were prepared and studied. at birth the middle ear is mostly filled with mesenchyme and small in size, having only a small hypotympanum and a very small epitympanic recess. during the first postnatal two weeks, much of the hypertrophy found in the adult middle ear develops. because an entotympanic element is nev er formed, the previously called entotympanic chamber is here renamed the hypotympanum. the e ... | 1975 | 1142445 |
| the effects of delta-9-tetrahydrocannabinol on actin microfilaments. | fluorescence staining with rhodamine phalloidin specific for f-actin was employed to examine the effects of delta-9-tetrahydrocannabinol (thc) on the distribution of microfilaments in kangaroo rat epithelial cells (ptk2) and rabbit aortic endothelial cells (rae). ptk2 cells were more sensitive to thc treatment than rae cells. exposure of ptk2 cells to 10 microm thc for 2 h disrupted the microfilament network. after treatment with 20 microm thc for 2 h there was a loss of cell-to-cell contact bet ... | 1990 | 2175259 |
| effects of a low op dose on seed/bead discrimination in the kangaroo rat, dipodomys. | | 1989 | 2758144 |
| the sequence of the 3.3-kilobase repetitive element from dipodomys ordii suggests a mechanism for its amplification and interspersion. | dna from the kangaroo rat, dipodomys ordii, contains a 3.3-kb, highly repeated sequence that is interspersed throughout the genome in small tandem clusters. one 3.3-kb unit has been cloned into pbr322 and the nucleotide sequence determined. the clone used was shown to be representative of the bulk of such sequences found in the genomic dna. the sequence contains 10 homologous subunits each ca. 260 bp in length. comparison of these to one another yielded a 258-bp consensus sequence containing a 3 ... | 1987 | 3041011 |
| spatial and temporal continuity of kangaroo rat populations shown by sequencing mitochondrial dna from museum specimens. | the advent of direct sequencing via the polymerase chain reaction (pcr) has opened up the possibility of molecular studies on museum specimens. here we analyze genetic variation in populations over time by applying pcr to dna extracted from museum specimens sampled from populations of one species over the last 78 years. included in this study were 43 museum specimens of the panamint kangaroo rat dipodomys panamintinus from localities representing each of three geographically distinct subspecies. ... | 1990 | 2120448 |
| parasitic and phoretic arthropods of the elephant-eared and the santa cruz kangaroo rats. | the parasitic and phoretic arthropods of the elephant-eared kangaroo rat (dipodomys elephantinus) and santa cruz kangaroo rat (d. venustus) are reported; most of these represent new host records. thirteen of 14 (93%) of d. elephantinus and 11 of 12 (92%) of d. venustus had 11 and nine arthropod species, respectively. larval and nymphal stages of the tick dermacentor occidentalis were the most prevalent parasite (77%) on d. elephantinus whereas the mesostigmatid mite androlaelaps fahrenholzi was ... | 1991 | 2067062 |
| wood rats and kangaroo rats: potential reservoirs of the lyme disease spirochete in california. | the etiologic agent of lyme disease, borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner, was isolated repeatedly from dusky-footed wood rats, neotoma fuscipes baird, and california kangaroo rats, dipodomys californicus merriam, in northern california. all animals were collected in a region endemic for lyme disease but for which the natural reservoir of b. burgdorferi was unknown. similar attempts to isolate spirochetes from lizards, other species of rodents, jack rabbits, and deer ... | 1991 | 1875357 |
| genomic structure and sequence variation of a 3.3-kb repeat dna element of the kangaroo rat, dipodomys ordii. | the genomic structure and sequence variation of a 3.3-kb repeat dna element, representing 5% of the genome of the kangaroo rat dipodomys ordii, has been investigated. most of the repeats are arranged in tandem arrays of 50 kb or more. thirteen randomly selected genomic clones have been mapped with twelve restriction enzymes. the frequency of sequence divergence in the genomic clones is 0.5%. the clone maps and the genomic structure studies have permitted the characterization of a number of varia ... | 1988 | 3215518 |
| spatial memory and adaptive specialization of the hippocampus. | the hippocampus plays an important role in spatial memory and spatial cognition in birds and mammals. natural selection, sexual selection and artificial selection have resulted in an increase in the size of the hippocampus in a remarkably diverse group of animals that rely on spatial abilities to solve ecologically important problems. food-storing birds remember the locations of large numbers of scattered caches. polygynous male voles traverse large home ranges in search of mates. kangaroo rats ... | 1992 | 1384199 |
| vertical distribution of soil removed by four species of burrowing rodents in disturbed and undisturbed soils. | burrow volumes were determined in disturbed and undisturbed soils for four species of rodents in southeastern idaho. comparisons were made between soil types for the average volume and the proportion of the total volume of soil excavated from 10-cm increments for each species, and the relative number of burrows and proportion of total soil removed from beneath the minimum thickness of soil covers over buried low-level radioactive wastes. burrows of montane voles (microtus montanus) and deer mice ... | 1988 | 3280518 |
| the fine structure of the trophospongial layer of the kangaroo rat placenta. | the trophospongial layer of the near-term kangaroo rat placenta was examined in the electron microscope. two ultrastructurally different cellular zones were distinguishable - an inner zone adjacent to the labyrinth and a basal zone located mesometrial to the inner zone. inner zone cells contained a well developed granular er and golgi apparatus as well as polymorphous membrane-limited granules. the cells also contained modest amounts of glycogen and lipid droplets. basal zone cells were also ric ... | 1975 | 1200411 |
| projections of the trapezoid body and the superior olivary complex of the kangaroo rat (dipodomys merriami). | glass micropipettes filled with 2 m sodium cyanide were used to physiologically locate and iontophoretically damage the nucleus of the trapezoid body (ntb), the medial superior olive (mso), and the lateral superior olive (lso). mechanical lesions were made in the trapezoid body as it leaves the cochlear nuclei. after a 3- to 10-day survival time the projections and terminal degeneration were traced with the fink-heimer and nauta-gygax stains. the ventral cochlear nucleus (vcn) projects via the t ... | 1975 | 1192176 |
| functional characteristics of superior olivary neurons to binaural stimuli. | this investigation was undertaken to study the timing properties of low-frequency binaural neurons located in the medulla of kangaroo rat (dipodomys spectabilis). the results show that the response variables, vector strength (vs) and discharge rate (dr), are not necessarily related responses; each may be conveying a different parameter of acoustic stimuli. the results also lead to the conclusion that binaural low-frequency neurons, whether they are excitatory-excitatory (ee) or excitatory-inhibi ... | 1975 | 1177003 |
| food-deprivation-induced polydipsia in two species of kangaroo rats. | | 1975 | 1144612 |
| helminths of sympatric populations of kangaroo rats (dipodomys ordii) and grasshopper mice (onychomys leucogaster) from the high plains of eastern new mexico. | during a 1-yr period 124 dipodomys ordii and 92 onychomys leucogaster were trapped from the same locality and were examined for helminths. only 1 cestode species (catenotaenia linsdalei) was recovered from d. ordii, whereas o. leucogaster was infected with 2 nematoda (litomosoides carinii, mastophorus muris), 2 cestoda (hymenolepis citelli, and 1 unknown), and 1 acanthocephalan (moniliformis clarki) species. all represent new host and distribution records. | 1985 | 4057002 |
| coccidia from california kangaroo rats (dipodomys spp.). | | 1985 | 4057012 |
| timing of replication of the satellite and main band dnas in cells of the kangaroo rat (dipodomys ordii). | | 1972 | 4117038 |
| location of satellite dnas in the chromosomes of the kangaroo rat (dipodomys ordii). | | 1973 | 4125443 |
| [sleep in the kangaroo rat (potorous apicalis). a study in the adult and in the young one month before final leaving of the pouch. effects of weaning]. | | 1974 | 4138249 |
| responses of merriam's kangaroo rats, dipodomys merriami, to various levels of carbon dioxide concentration. | | 1973 | 4145439 |
| physiological and ecological studies on the chisel-toothed kangaroo rat, dipodomys microps. | | 1973 | 4145768 |
| central auditory system of the kangaroo rat, dipodomys merriami. | | 1968 | 4185131 |
| ultrastructural changes in the neural lobe of the hypophysis of the kangaroo rat (dipodomys merriami) following intraperitoneal injection of hypertonic sodium chloride. | | 1969 | 4185961 |
| autoradiographic studies of the replication of satellite dna in the kangaroo rat. autoradiographs of satellite dna. | | 1974 | 4280447 |
| histo-pathological changes in cold-exposed kangaroo rats, dipodomys merriami. | | 1971 | 4397890 |
| energy metabolism and body water turnover rates of two species of free-living kangaroo rats, dipodomys merriami and dipodomys microps. | | 1971 | 4397891 |
| blood composition in normothermic and hyperthermic kangaroo rats dipodomys merriami and laboratory rats rattus norvegicus. | | 1972 | 4405342 |
| a possible relationship between satellite dna and the evolution of kangaroo rat species (genus dipodomys). | | 1972 | 4509020 |
| satellite dna and cytogenetic evolution. dna quantity, satellite dna and karyotypic variations in kangaroo rats (genus dipodomys). | the genus dipodomys (kangaroo rats) exhibits major interspecies variations in the proportions of highly reiterated satellite dna sequences in the genome as well as in the chromosome number and the proportions of uni-armed and bi-armed chromosomes. for nearly all of the approximately 22 species of the genus and several subspecies, liver dna was distributed in neutral cscl buoyant density gradients into four fractions; principal dna (1.698 g/ml), intermediate-density dna (1.702 g/ml), ms satellite ... | 1976 | 1001153 |
| importance of green vegetation for reproduction in the kangaroo rat, dipodomys merriami merriami. | | 1973 | 4706256 |
| histochemical observations on placentation of the kangaroo rat (dipodomys) with special reference to the trophospongium and giant cells. | | 1973 | 4731810 |
| implications of karyotypic variation in the kangaroo rat, dipodomys heermanni. | | 1973 | 4761364 |
| seasonal variation in moonlight avoidance by bannertail kangaroo rats. | | 1974 | 4819590 |
| vocalization in merriam's kangaroo rat. | | 1974 | 4833191 |
| effect of running on water balance of the kangaroo rat. | | 1972 | 5022381 |
| biological half-life studies of tritium in chronically exposed kangaroo rats. | | 1972 | 5025235 |
| nutrition requirements of the kangaroo rat (dipodomys ordii) as indicated by dietary self-selection. | | 1972 | 5035252 |
| kangaroo rat auditory thresholds before and after middle ear reduction. | | 1972 | 5072747 |
| classification of subpopulations of neurons in the cochlear nuclei of the kangaroo rat. | | 1972 | 5077556 |
| histocytochemical pattern of enzyme distribution in cochlea of the kangaroo rat (d. spectabilis) at rest and following auditory stimulation. | | 1971 | 5095494 |
| characteristic delay neurons in the inferior colliculus of the kangaroo rat. | | 1971 | 5110223 |
| central nervous regulation of body temperature during sleep. | the relationship between hypothalamic temperature and metabolic heat production was measured during wakefulness, slow-wave sleep, and paradoxical sleep in unrestrained kangaroo rats (dipodomys). hypothalamic temperature was manipulated with chronically implanted, water-perfused thermodes while cortical electroencephalogram, electromyogram, metabolic rate, and body movement were continuously recorded. during slow-wave sleep, in comparison to wakefulness, there is a lowered threshold hypothalamic ... | 1976 | 973138 |
| projection of the cochlea to cochlear nuclei in merriam's kangaroo rat. | | 1971 | 5134323 |
| karyotypes of the panamint kangaroo rat (dipodomys panamintinus (merriam)). | | 1971 | 5144880 |
| ascending and descending projections of the inferior colliculus in the kangaroo rat (dipodomys merriami). | | 1971 | 5148388 |
| daily cycles of hibernation in the kangaroo rat, dipodomys merriami. | | 1971 | 5156357 |
| adaptive value of hearing and vision in kangaroo rat predator avoidance. | | 1971 | 5165734 |
| organ weights and serum total cholesterol in the kangaroo rat (dipodomys merriami). | | 1969 | 5351971 |
| evaporative water loss and gross effects of water privation in the kangaroo rat, dipodomys venustus. | | 1969 | 5373855 |
| neuronal responses of kangaroo rat ventral cochlear nucleus to low-frequency tones. | | 1970 | 5411028 |
| response diversity of neurons in ventral cochlear nucleus of kangaroo rat to low-frequency tones. | | 1970 | 5439342 |
| ecology and radiation exposure of kangaroo rats living in a tritiated environment. | | 1970 | 5473402 |
| satellite dna's in the kangaroo rat. | | 1970 | 5490264 |
| intranuclear distribution of satellite dna from kangaroo rat. | | 1970 | 5490345 |
| energy expenditure of running kangaroo rats dipodomys merriami. | | 1970 | 5515607 |
| preferential loss of kangaroo chromosomes in hybrids between chinese hamster and kangaroo-rat somatic cells. | | 1970 | 5531375 |
| karyotypes of kangaroo rats from southern california. | | 1971 | 5545558 |
| glycogen content in the outer hair cells of kangaroo rat (d. spectabilis) cochlea prior to and following auditory stimulation. | | 1971 | 5561985 |
| eimeria balphae n. sp. from the ord kangaroo rat dipodomys ordii. | | 1967 | 5629072 |
| hematopathologic surveys of kangaroo rats (dipodomys microps) populating plutonium contaminated regions of the nevada test site. | | 1968 | 5688316 |
| comparative histochemical investigation of the organ of corti in the kangaroo rat, gerbil, and guinea pig. | | 1968 | 5716435 |
| the ultrastructure of the placental labyrinth in the kangaroo rat, dipodomys. | | 1969 | 5776881 |
| a hermaphroditic kangaroo rat. | | 1965 | 5891271 |
| natural free-running period in vertebrate animal populations. | regression analysis (analysis of covariance) is contrasted with the conventional "mean period length" for estimating the length of period of the spontaneous activity frequency (free-running period) in population samples of gila monsters (heloderma suspectum) and kangaroo rats (dipodomys merriami) in the sonoran desert. the mean period length in each population does not differ significantly from 24:00 hours (p > .05) and it does not differ significantly (p > .05) between the species studied; the ... | 1967 | 6021681 |
| specific subtotal labyrinthectomy of the superior semicircular canals of the kangaroo rat. | | 1967 | 6034493 |
| eimeria scholtysecki n. sp. from ord's kangaroo rat dipodomys ordii. | | 1967 | 6038029 |
| seasonal variation in various blood indices of the kangaroo rat, dipodomys panamintinus. | 1. various blood indices in the panamint kangaroo rat revealed seasonal fluctuations. the red blood cell count during winter and summer averaged 7.2 +/- 1.0 x 10(6) and 9.2 +/- 0.2 x 10(6)/mm3 respectively. 2. the mean cell hemoglobin during winter and summer averaged 25 +/- 10.8 pg and 18.6 +/- 3.7 pg respectively. 3. these fluctuations may reveal a rapid rate of red blood cell destruction during winter in combination with a change in diet, concomitant to this, is an increase in mean cell hemog ... | 1982 | 6121650 |
| analysis of the frequency of sister chromatid exchange in different regions of chromosomes of the kangaroo rat (dipodomys ordii). | the frequency of sister chromatid exchanges (sces) has been determined for c band and non-c band regions of chromosomes of the kangaroo rat after staining with the fluorescence plus giemsa (fpg) technique. after one complete round of dna synthesis in the presence of bromodeoxyuridine (brdu) staining of the c band regions revealed simple or complex asymmetries between chromatids. after two complete rounds of dna synthesis in the presence of brdu "harlequin" chromosomes were observed. analysis of ... | 1976 | 964105 |
| [sleep in marsupio, the kangaroo rat (potorous apicalis)]. | | 1978 | 693605 |
| the red function of phage lambda mediates the alteration of an interspersed repeated dna sequence from the kangaroo rat dipodomys ordii. | the kangaroo rat d. ordii is shown to contain an interspersed repeated sequence 3.25 kb in length. this sequence undergoes alteration (deletions) when cloned into a red+ lambda vector but is stable in a red- vector. using the red- clone it is shown that deletions are the result of the activity of the lambda red, or e. coli rece, recombination systems. mixed infection experiments demonstrate that this activity is acting in trans. the deletions appear to yield fragments of specific size, suggestin ... | 1982 | 6294479 |
| wheel running of kangaroo rats, dipodomys merriami, as related to food deprivation and body composition. | kangaroo rats deprived of food ran themselves to death in 48 h in wheel cages. despite the loss of 14.5% of body weight the ratio of water to protein was the same after the run as it was in control rats. metabolic measurements at rest and in the running wheel and weight loss in the 48-h run were used to estimate fuels used and water expended. two-thirds of the initial amount of fat and 9% of the protein were metabolized. the terminal mean percentage of body fat was about twice that observed in r ... | 1978 | 627494 |
| nucleotide sequences of hs-alpha satellite dna from kangaroo rat dipodomys ordii and characterization of similar sequences in other rodents. | | 1977 | 597857 |
| preferential occurrence of sister chromatid exchanges at heterochromatin-euchromatin junctions in the wallaby and hamster chromosomes. | chromosomes of two mammalian species, the white-throated wallaby and the rat-like hamster, possessed large amounts of constitutive heterochromatin which is detectable as c bands. by making use of this character the frequency of sister chromatid exchanges (sces) was determined for the c band and the euchromatic regions of the chromosome. in both species, the distribution of sces in the euchromatin of chromosomes was found to be proportional to its metaphase length, while the number of sces locali ... | 1979 | 510085 |
| coccidia from kangaroo rats (dipodomys spp.) in the western united states, baja california, and northern mexico with descriptions of eimeria merriami sp. n. and isospora sp. | | 1983 | 6827438 |
| mechanical vs. ischemic mechanisms for decompression sickness. | we used 20 kangaroo rats to investigate the effect of exposure to low oxygen levels (0.11 atm 02 inspired partial pressure) prior to decompression from a steady-state condition. this hypoxia was found to afford significant protection against limb bends as simulated in those animals by tail biting. yet, it potentiated neurologic symptoms compared with a control exposure on air with the same level of nitrogen supersaturation. however the incidence of simulated limb bends in the same animals was th ... | 1979 | 464957 |
| effects of competition, colonization, and extinction on rodent species diversity. | analyses of long-term experimental data from the chihuahuan desert revealed that species diversity of other rodents was higher on plots from which kangaroo rats (dipodomys spp.) had been removed. the difference was due to consistently higher colonization and lower extinction probabilities of small granivorous rodents in the absence of competitively dominant kangaroo rats. the results of this ecosystem experiment demonstrate the importance of both competitive exclusion and metapopulation dynamics ... | 1995 | 7846530 |
| measurements on the kidneys and vasa recta of various mammals in relation to urine concentrating capacity. | maximum urine-concentrating capacity (ucc) differs widely among mammals of different species, being very high in some desert species (e.g. kangaroo rats) and very low in freshwater acquatic species (e.g. beaver). in this study, kidneys of 21 species of mammals from widely different habitats were studied in histological sections to determine whether differences in ucc can be attributed to differences in kidney structure. parameters studied included the ratio of medullary to cortical thickness, th ... | 1977 | 407772 |
| cns regulation of metabolic rate in the kangaroo rat dipodomys ingens. | water-perfused thermodes were chronically implanted around the preoptic nuclei and hypothalamus (poh) of kangaroo rats (dipodomys ingens). responses in rate of metabolic heat production to manipulations of poh temperature (thy) were measured in unanesthetized, unrestrained animals at ambient temperatures of 10, 20, 25, and 30 degreec. the threshold thy and the proportionally constant (alpha) for this response consistently decreased as ambient temperature increased, but alpha was not significan ... | 1975 | 168786 |
| mechanisms of chromosome banding. ix. are variations in dna base composition adequate to account for quinacrine, hoechst 33258 and daunomycin banding? | prior studies on subfractions of mouse and kangaroo rat dna have suggested that variations in base concentration within a given genome may not be great enough to account for q-banding. to examine this with another species, calf dna was subfractionated by cscl ultracentrifugation into gc-rich satellites and the main band dna was further fractionated into at-rich, intermediate and gc-rich portions. the effect of varying concentrations of these dnas on quinacrine and hoechst 33258 fluorescence was ... | 1976 | 61106 |
| kangaroo rat locomotion: design for elastic energy storage or acceleration? | mechanical stresses (force/cross-sectional area) acting in muscles, tendons and bones of the hindlimbs of kangaroo rats (dipodomys spectabilis) were calculated during steady-speed hops and vertical jumps. stresses were determined from both high-speed ciné films (light and x-ray) and force plate recordings, as well as from in vivo tendon force recordings. stresses in each hindlimb support element during hopping (1.6-3.1 m s-1) were generally only 33% of those acting during jumping (greater than o ... | 1988 | 3204333 |
| hearing in prairie dogs: transition between surface and subterranean rodents. | behavioral audiograms were determined for four black-tailed and one white-tailed prairie dogs (cynomys ludovicianus and c. leucurus) using a conditioned avoidance procedure. the hearing of black-tailed prairie dogs ranges from 29 hz to 26 khz and that of the white-tailed prairie dog from 44 hz to 26 khz (at sound pressure levels of 60 db). both species have good low-frequency hearing, especially black-tailed prairie dogs which can hear as low as 4 hz and are more sensitive than any other rodent ... | 1994 | 8188546 |
| radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the nevada test site. | between 1970 and 1986 the nevada applied ecology group (naeg), u.s. department of energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the nevada test site. in this paper, naeg studies conducted at two nuclear (fission) sites (ns201, ns219) and two nonnuclear (nonfission) sites (area 13 [project 57] and clean slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240pu ... | 1988 | 3198397 |