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944.
Roger Hillson Joel D. Alejandre Kathryn H. Jacobsen Rashid Ansumana Alfred S. Bockarie Umaru Bangura Joseph M. Lamin Anthony P. Malanoski David A. Stenger 《PloS one》2014,9(11)
This study demonstrates the use of bootstrap methods to estimate the total population of urban and periurban areas using satellite imagery and limited survey data. We conducted complete household surveys in 20 neighborhoods in the city of Bo, Sierra Leone, which collectively were home to 25,954 persons living in 1,979 residential structures. For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images. We used bootstrap statistical methods to estimate the total population of the pooled sections, including the associated uncertainty intervals, as a function of sample size. Evaluations based either on rooftop area per person or on the mean number of occupants per residence both converged on the true population size. We demonstrate with this simulation that demographic surveys of a relatively small proportion of residences can provide a foundation for accurately estimating the total population in conjunction with aerial photographs. 相似文献
945.
Joseph W. Towner 《American journal of botany》1962,49(10):1064-1067
Towner , Joseph W. (U. California, Los Angeles.) Cytogenetics of Tagetes jaliscensis X T. erecta. Amer. Jour. Bot. 49(10): 1064–1067. Illus. 1962.—Although Tagetes jaliscensis and T. erecta are morphologically very distinct, the F1 hybrid between them had normal meiosis (12 bivalents) and was fertile. Segregation in F2 was undisturbed for marker genes on 4 pairs of chromosomes. These facts suggest that T. jaliscensis, like T. erecta, is an A-genome diploid (genome formula A2A2). From plant morphology, the A-subgenome of amphiploid T. patula is regarded as more likely derived from T. erecta than from T. jaliscensis. In T. jaliscensis X erecta F2, disk corolla anthocyanin (R = red) from T. jaliscensis segregated as a simple dominant over the absence of anthocyanin from T. erecta. A chlorophyll defect was determined by duplicate factor recessives. Tubular ray flowers (tu = tubular) segregated as a simple recessive to normal flat rays in the interspecific F2 and in T. erecta. 相似文献
946.
Walter Heiligenberg Curtis Baker Joseph Bastian 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1978,124(3):211-224
Summary Gymnotoid electric fish with pulse-type electric organ discharges (EODs) shorten (lengthen) their EOD intervals as pulses of a slightly slower (faster) train scan their EODs (Figs. 1, 2). They thus minimize the chance of pulse coincidence by transient accelerations (decelerations) of their EOD rate.Studies in curarized preparations demonstrate that this Jamming Avoidance Response (JAR) is controlled by electroreceptive input alone and without reference to an internal electric organ pacemaker-related signal (Fig. 8). A sufficient stimulus input consists of a train of strong, EOD-like stimulus pulses (S1), which mimic the animal's experience of its own EOD, and a train of small pulses (S2) of slightly different repetition rate, which mimic EODs of a neighbor. Correct behavioral responses require S1 pulses of sufficient intensity to recruit pulse-markertype receptors; also spatial and temporal patterns must closely resemble those of the animal's EOD. These features are of little significance for S2 pulses which, while scanning S1 pulses, only provide a small perturbation of electroreceptive feedback from S1 pulses. Inappropriate S1 stimulation impairs and sometimes reverses (Fig. 7) the behavioral discrimination of scan directions. The JAR is explained in terms of excitatory and inhibitory processes (Fig. 3) which are triggered by S2 stimulation, at specific phases within the S1 cycle (Figs. 4–6).The JAR in pulse species strongly resembles the JAR in wave-species (Bullock et al., 1972) and could be considered an evolutionary ancestor of the latter. It is a response to a particular novelty in electroreceptive feedback.We thank Drs. T.H. Bullock, C. Hopkins and an anonymous referee for most helpful criticism. This research was supported by NSF grand BMS74-18640 and NIMH grant PHSMH-2614901 to W.H. and NIH grant/ROI NS 12337-01 to J.B. 相似文献
947.
Leila J. Walker M.S. Joseph W. Landau M.D. Hisako Nishihara Sc.D. Victor D. Newcomer M.D. 《Mycopathologia》1965,27(3-4):301-304
Summary The level of haptoglobin was determined in control rats and in rats infected withC. immitis. The haptoglobin levels in the infected group were significantly higher than in those in the control group. The possibility that serial determinations may be of value in following the course of this disease is currently being investigated.This study was supported in part by USPHS Grants A1-06048-01, 5 T1 A1 52–06 and the Dermatologic Research Foundation of California, Inc. 相似文献
948.
Long-term (including gestational and lactational) restriction of protein (8% of diet) significantly lowered the absolute and relative consumption of 6% ethanol (EtOH) in a two-bottle, free-choice (H2O vs EtOH) situation during a 76-day test period. This difference in response between rats fed the low protein diet and those fed an isocaloric normal protein (24%) diet became non-significant in two subsequent 100-day test periods. Statistical analysis of observations on individual performance indicated that regularity, cyclicity, and duration of drinking in each animal was random over all three time intervals for both groups. The early, significantly lower EtOH consumption by the protein-restricted group may be due to a paucity of EtOH-metabolizing enzymes in brain and liver, thereby prolonging the CNS effects of lower doses of EtOH consumed. The disappearance of this difference in subsequent test periods may reflect either a behavioral or metabolic adaptation in the developing protein-deficient rat. 相似文献
949.
Dispersed from a dry film into buffer (5 mM phosphate, 0.15 M NaCl, pH 7.4), the liponucleotide 1-β-d-arabinofuranosylcytosine 5′-diphosphate l-1,2-diacylglycerol (ara-CDPdiacylglycerol) spontaneously forms vesicles which are several microns in diameter and probably unilamellar. Their average size immediately begins to decrease, and after 2 h none can be seen in the light microscope. During 1–2 days in unstirred solutions at 25°C, the vesicles are transformed to spherical or nearly spherical micelles having an apparent partial specific volume of 0.835 ml·g?1, a maximum possible aggregation number of about 150, and an anhydrous radius of about 37 Å. The critical micelle concentration (CMC) is about 10 μM in buffer and 20 μM in distilled water, but micelle-monomer equilibration requires at least 1 week at a total concentration of 66 μM. This exceedingly slow equilibration is unique among reported detergents. The standard enthalpy and entropy of micellization are ?13 kJ·mol?1 and 87 J·mol?1·K?1, respectively. These values are within the range reported for other detergents. Sonication accelerates the vesicle-micelle transformation to 30 min. 相似文献
950.
Edmond Y. Lau Sergio E. Wong Sarah E. Baker Jane P. Bearinger Lucas Koziol Carlos A. Valdez Joseph H. Satcher Jr Roger D. Aines Felice C. Lightstone 《PloS one》2013,8(6)
In nature, the zinc metalloenzyme carbonic anhydrase II (CAII) efficiently catalyzes the conversion of carbon dioxide (CO2) to bicarbonate under physiological conditions. Many research efforts have been directed towards the development of small molecule mimetics that can facilitate this process and thus have a beneficial environmental impact, but these efforts have met very limited success. Herein, we undertook quantum mechanical calculations of four mimetics, 1,5,9-triazacyclododedacane, 1,4,7,10-tetraazacyclododedacane, tris(4,5-dimethyl-2-imidazolyl)phosphine, and tris(2-benzimidazolylmethyl)amine, in their complexed form either with the Zn2+ or the Co2+ ion and studied their reaction coordinate for CO2 hydration. These calculations demonstrated that the ability of the complex to maintain a tetrahedral geometry and bind bicarbonate in a unidentate manner were vital for the hydration reaction to proceed favorably. Furthermore, these calculations show that the catalytic activity of the examined zinc complexes was insensitive to coordination states for zinc, while coordination states above four were found to have an unfavorable effect on product release for the cobalt counterparts. 相似文献