Variety Of Surfaces Research Articles

A Population Pharmacokinetic and Pharmacodynamic Evaluation of Pralatrexate in Patients with Hematologic Malignancies.

Pralatrexate is a novel antifol designed to have high affinity for the reduced folate carrier, exhibiting improved internalization over other analogues. Phase 2 and subsequent Phase 1 studies revealed that patients with lymphoma exhibited a higher incidence of mucositis, compared to that reported in patients with solid tumors. The initial Phase 2 experiences employed dose escalation on an every other week schedule (135 to 240 mg/m2 QOW) while the follow-on Phase 1 and 2 studies employed a weekly dosing schedule (30 to 45 mg/m2 weekly for 6 of 7 weeks). The maximum tolerated dose (MTD) was 30 mg/m2 weekly for 6 of 7 weeks in lymphoma patients. Preliminary population pharmacokinetic (PK) and adverse event (AE) evaluations suggested that pralatrexate exposure could be controlled with weight or body size based dosing, and that pretreatment with folic acid and vitamin B12 could abrogate the mucositis. PK and AE data from 47 patients were evaluated using NONMEM Version V level 1.1. Model building followed standard approaches. The best PK model was a three compartment linear model, fitted to the natural log-transformed concentration versus time data. Patient weight and methylmalonic acid (MMA) were found to be predictive of inter-patient PK variability, supporting weight or body surface area (BSA) based dosing. There are observations of an apparent association between MMA concentrations and PDX PK which need to be further explored. The PK model was evaluated using bootstrapping and a visual predictive check. An ordered categorical logistic regression was conducted to evaluate the relationship between pralatrexate exposure and grade of mucositis. In this evaluation, pralatrexate area under the curve (AUC) and MMA were found to be predictive of toxicity, where patients with higher MMA or AUC had a higher probability of mucositis. Individualized dosing combined with vitamin pretreatment significantly improved the toxicity profile, allowing for a shift in the dose-limiting toxicity (DLT) from mucositis to thrombocytopenia. Although the data from the present study were limited, the covariates identified in the population PK and adverse event evaluations were comparable with those identified for other anti-folate agents. MMA is a sensitive indicator of vitamin B12 deficiency and its impact on toxicity is commonly reported for this class of agents. The rationale behind the influence of MMA on clearance is less clear and may be correlated with other aspects of patient health. Pralatrexate has exhibited promising activity in patients with chemotherapy refractory peripheral T-cell lymphoma, leading now to an international multi-center Phase 2 study in peripheral T-cell lymphoma. The application of a population PK model based analysis was a critical component in the development of this agent. Model-based evaluations allowed the identification of the safest schedules and supported the need for vitamin supplementation for the safe administration. [Display omitted]

A high‐resolution simulation of the ocean during the POMME experiment: Mesoscale variability and near surface processes

This article is the second part of a modeling study of upper ocean mesoscale physical processes in an area of the northeast Atlantic that was extensively sampled during the Programme Océan Multidisciplinaire Méso‐Echelle (POMME experiment, October 2000–September 2001). The model is a high‐resolution regional version of the ocean general circulation model OPA integrated from February to May 2001. The mesoscale upper ocean dynamics has been carefully validated in a first paper (Paci et al., 2005). In the present article, the simulation is used to analyze the contribution of mesoscale eddies to the mixed layer processes during the period that controls the annual subduction rate and the characteristics of the subducted water. Mesoscale eddies account for a significant part of the mixed layer heat, salt, and water budgets through mesoscale and submesoscale structures acting on the horizontal advective terms. They represent respectively 52% and 66% of the horizontal advection of temperature and salinity and 70% of the lateral induction. They also induce an earlier and more intense restratification. The domain‐averaged detrainment appears to be reduced by more than 15% by mesoscale eddies and reaches about 0.8 Sv. However, these eddies increase the density of the detrained water. Some dense water, likely to be involved in the formation of subpolar mode water, is detrained by them in a way that maximizes its chance to be effectively subducted in the area.

Microbial Biofilms: A Potential Source for Alloplastic Device Failure

A biofilm is defined as an assemblage of surface-asso-ciated (not easily removed) microbial cells that are en-closedinaprotectiveextracellularprimarilypolysaccha-ride matrix. Biofilms may form on a wide variety ofsurfaces, including living tissues, natural aquatic sys-tems, industrial or potable water system piping, or im-planted medical devices.

3D ultrasound analysis of carotid plaque volume and surface morphology

Morphological characterization of carotid plaques has been used for risk stratification and evaluation of response to therapy, evaluation of new risk factors, genetic research, and for quantifying effects of new anti-atherosclerotic therapies. We developed a 3D US system that allows detailed studies of carotid plaques in 3D. Our software includes 3D reconstruction, viewing, manual and semi-automated segmentation of carotid plaques, and surface morphology analysis to be used for quantitative tracking of plaque changes. We evaluated our plaque quantification software by examining plaque volume measurement accuracy, variability, and plaque surface morphology. We used vascular test phantoms to study segmentation accuracy, and used 48 3D US carotid plaques of patients ranging in size from 13.2 mm 3 to 544.0 mm 3 to study plaque volume measurement variability. We compared results from the semi-automated plaque measurements to the results obtained from manual measurements, which were used as the “gold” standard. We developed a surface plaque morphology quantification technique based on the segmented plaque surface curvature and used it to analyze plaques. Accuracy of plaque volume measurements for the simulated plaques ranged from 4.2% to 1.5% for volumes ranging from 68.5 mm 3 to 286 mm 3. The variability study showed that coefficients of variation in the measurement of plaque volume decreased with increasing plaque size for both inter- (90.8–3.9%) and intra-observer (70.2–3.1%) measurements over the plaque sizes measured. Surface morphology analysis showed that 1 mm ulceration could be quantified and monitored for changes over time. The automated plaque quantification approach showed a little higher intra-observer variability than the manual technique, and its performance was better for segmenting the wall than the lumen. Our results indicate that our approach is sensitive tool and can be used in studies of plaque progression and regression as it relates to atherosclerosis treatment effects and can be used effectively in longitudinal studies for direct measurement carotid plaque volume.

Polar vortex controls coupling of North Atlantic Ocean and atmosphere

The structure of the North Atlantic leading atmospheric winter variability mode strongly depends on the state of the polar stratospheric vortex. If the polar vortex is strong, one teleconnection pattern emerges in the upper troposphere, while two mostly independent ones appear when the vortex is weak. The anomaly patterns associated with the different polarities of these modes show strong differences in the wind fields and in the correlation of atmospheric variability with the sea surface temperature of the North Atlantic. Only when the polar vortex is strong, does a basin‐wide tripole correlation pattern exist between tropospheric variability and sea surface temperature. Under weak vortex conditions one of the variability modes correlates with the subtropical, the other with the subpolar gyre. These results suggest that a NAO index based on near surface pressure that fails to account for the state of the polar vortex is a suboptimal representation of the tropospheric circulation variability.

Tropical Multidecadal and Interannual Climate Variability in the NCEP–NCAR Reanalysis

Abstract The leading tropical multidecadal mode (TMM) and tropical interannual (ENSO) mode in the 52-yr (1949– 2000) NCEP–NCAR reanalysis are examined for the December–February (DJF) and June–August (JJA) seasons based on seasonal tropical convective rainfall variability and tropical surface (land + ocean) temperature variability. These combined modes are shown to capture 70%–80% of the unfiltered variance in seasonal 200-hPa velocity potential anomalies in the analysis region of 30°N–30°S. The TMM is the dominant mode overall, accounting for 50%–60% of the total unfiltered variance in both seasons, compared to the 22%–24% for ENSO. The robustness of the tropical multidecadal mode is addressed, and the results are shown to compare favorably with observed station data and published results of decadal climate variability in the key loading regions. The temporal and spatial characteristics of this mode are found to be distinct from ENSO. The TMM captures the global climate regimes observed during the 1950s–6...

How realistic is the high‐frequency signal of a 0.1° resolution ocean model?

This paper describes the results from a comparative wavelet analysis of a 0.1, 40‐level Parallel Ocean Program model simulation of the North Atlantic with coincident in situ measurements of sea surface height (SSH) and temperature. The wavelet analysis is used to examine the realism of the surface's variability and its high‐frequency signals (less than a year). Along the coast, it shows that the model's simulated fields of SSH are realistic with the correlations to tide gauge measurements on the order of 0.8. The wavelet spectra show that the model replicates the observations' frequency space. Comparisons of the model's temperatures to temperatures from NOAA buoys north and south of the Gulf Stream show that, while not replicating the location of mesoscale features all the time, the model's energy in the strong mesoscale regions compares favorably to data. Due to the TOPEX/POSEIDON's (T/P) sampling, which requires large areal averages and because of the model's spontaneous eddy field, the evaluation of the simulation in the open ocean is less conclusive. The model does show similarities to the T/P data at high latitudes where the sampling by the sensor is denser and also on the eastern side of the basin with its lower mesoscale activity. Spatially, there are similarities in the amplitude of the signals between the model and the observations in areas with a significant signal in a given spectral band.

Chemical Variation and Catchment Characteristics in High Altitude Lochs in Scotland, U.K.

Previous research has established clear relationshipsbetween the chemical composition of surface waters andthe nature of their contributing catchments. Theserelationships are particularly strong when broadenvironmental gradients are considered. However, forfreshwaters at higher altitudes, some of the catchmentprocesses that mediate chemical composition are lessinfluential than those at lower altitudes. The waterchemistry of 85 upland lochs in Scotland, U.K. is examinedto assess differences in chemical composition along arelatively short altitude gradient. Principal componentsanalysis identifies the main gradients of variationwithin the dataset. A series of digital datasets is usedto characterise the catchments according to a range ofattributes including soils and landcover. Multivariatestatistical analysis is undertaken to examine the extentto which the catchment attributes can explain variationin surface water chemistry in upland systems. Theseempirical relationships may be used in the development ofregionalisation procedures, which will allow upscaling ofknowledge from individual sites to regions.

FFT analysis on NDVI annual cycle and climatic regionality in Northeast Brazil

AbstractBy considering that the climate of Northeast Brazil (NEB) has distinct wet and dry seasons, the mixed radix fast Fourier transform (mrFFT) algorithm, developed at the National Aerospace Centre of the Netherlands, was applied to a monthly Normalized Difference Vegetation Index (NDVI) time series from July 1981 to June 1993, to generate phase, amplitude and mean NDVI data using a 1‐year frequency in order to improve the analysis of its spatial variation.The NDVI mean values varied from >0.7, which occurred in northwest and southeast regions, to <0.3 in the northeast and 0.4 in the southwest regions of the NEB. The 90° phase month at its maximum amplitude occurred in August and was observed in both southeastern and northwestern coasts, located at 10.5°S–37.5°W and 4°S–46°W, respectively. It changed rapidly from August, June to May, moved inland and changed gradually from May through to April and from March to February, then moved towards the centre Dry Polygon area. Then it changed gradually from February to January and ended up in December, and moved further southwards. The annual cycle amplitude varied from <0.075 in northwest and southeast regions to >0.25 in the northeast region. By using spatial variations of phase, amplitude and mean NDVI values, 15 climate types were delineated for the NEB.The spatial distribution of climate types in the NEB delineated by the NDVI FFT analysis agreed mostly with the climatic types presented by Hargreaves (Precipitation dependability and potentials for agricultural production in Northeast Brazil. Empresa Brasileira de Pesquisa Agropecuária‐EMBRAPA, Brazil, 1974), except regions with higher spatial variability and limited surface meteorological data. Among the three components: phase, amplitude and mean NDVI, the phase image, informing the initiation and duration of rainy season, was the most important component for climate‐type delineation. Nevertheless, while the extreme values of amplitude, inferring a high wet–dry rainfall regime contrast, and mean NDVI, inferring annual rainfall total, occurred in the same phase area, amplitude and mean NDVI images were used for further delineation. It is concluded that the application of the mrFFT algorithm to NDVI time series analysis is an effective method for identifying vegetation phenology and hence to delineate the transit spatial change of climate types. Our further study is to construct and validate the alternative El Niño–Southern Oscillation (ENSO) drought onset model for each of the 15 climate types delineated for the NEB. Copyright © 2001 Royal Meteorological Society

A comparison of overground and treadmill running for measuring the three-dimensional kinematics of the lumbo–pelvic–hip complex

Objective. To compare overground and treadmill running for differences in the three-dimensional angular kinematics of the lumbo–pelvic–hip complex. Design. A within-subject repeated measures design. Background. The treadmill is an attractive research instrument as speed and slope are easily controlled and the required calibration volume is reduced. However, the degree to which treadmill running simulates overground running has not been resolved in the literature to date. Methods. 10 able-bodied subjects ran overground and on a treadmill at a self-selected speed. The treadmill speed was matched to each subjects respective average overground speed. The time–distance and the three-dimensional angular kinematic data were captured using a passive marker based motion analysis system. A set of angular and temporal kinematic parameters were extracted from the data and subjected to statistical analyses. Results. Significant differences were found between overground and treadmill running for all the time–distance parameters. Despite this, the kinematics of the lumbar spine and pelvis were similar between the two running conditions, with only three parameters being significantly different. These were lumbar extension at initial contact, anterior pelvic tilt at initial contact and the first maximum anterior pelvic tilt. Hip flexion-extension parameters were also only found to display subtle differences. Of the 17 hip parameters analysed, only hip flexion at initial contact, maximum hip flexion at loading response, hip extension at toe off, maximum hip extension and hip flexion-extension range of motion were found to be significantly different. Conclusion. A high powered treadmill with a minimal belt speed fluctuation is capable of being used to obtain a representation of the typical three-dimensional kinematic pattern of the lumbo–pelvic–hip complex during running. Relevance In order for the treadmill to be accepted as a useful research and/or clinical assessment instrument, it must be demonstrated that it does not significantly alter the performance of the evaluated activity. In this respect, a treadmill with minimal intra-stride belt speed variability and similar surface stiffness to the relevant overground condition is likely to be capable of being used to obtain a representation of the typical human running action for well accommodated subjects.

Correlations among Charcoal Records of Fires from the Past 16,000 Years in Indonesia, Papua New Guinea, and Central and South America

Microscopic charcoal preserved in lake and swamp sediments from 10 sites in Indonesia and Papua New Guinea and from 5 sites in Central and South America have been used to reconstruct long-term fire histories for these two regions. Comparison of these records demonstrates that fire is promoted during periods of rapid climate change and high climate variability, regardless of the presence or absence of humans. Broad synchrony of changes in corrected charcoal values in each region supports an atmospheric transmission of the climate signal via the dominant large-scale atmospheric circulation systems (Walker Circulation) that appears to have persisted since 16,000 cal yr B.P. Altered climate boundary conditions under the influence of changing El Niño-related variability, insolation, sea level, and sea surface temperature all influenced the strength of this connection. Correlation of biomass burning records between the regions tends to increase in the Holocene. The main period of inverse correlation occurs during the Younger Dryas Stade, when extratropical climate most affected the tropics. The strongest correlation between the two regions postdates 5000 cal yr B.P., when El Niño-related variability intensified. Fluctuations in tropical biomass burning are at least partly controlled by orbital forcing (precession), although extratropical climate influences and human activity are also important.

Rifins: a second family of clonally variant proteins expressed on the surface of red cells infected with Plasmodium falciparum.

Many pathogens evade the host immune response or adapt to their environment by expressing surface proteins that undergo rapid switching. In the case of Plasmodium falciparum, products of a multigene family known as var are expressed on the surface of infected red cells, where they undergo clonal antigenic variation and contribute to malaria pathogenesis by mediating adhesion to a variety of host endothelial receptors and to uninfected red blood cells by forming rosettes. Herein we show that a second gene family, rif, which is associated with var at subtelomeric sites in the genome, encodes clonally variant proteins (rifins) that are expressed on the infected red cell surface. Their high copy number, sequence variability, and red cell surface location indicate an important role for rifins in malaria host-parasite interaction.

Earth weather and climate control: can space technology contribute?

With ongoing progress in space technology, questions of its potential for the modification of weather and climate phenomena (often summarized by the term ‘geoengineering’) ranging from small-scale severe weather events to mitigation of effects caused by global climate change and ozone depletion have become popular. This paper reviews the current state of scientifically based studies in this context and attempts to provide a basis for an assessment of geoengineering efforts with respect to technological, economic and fundamental scientific aspects. The overview indicates that the current state of knowledge about climate variability as a consequence of natural and anthropogenic influences is sufficient to classify geoengineering solutions as highly risky and their consequences as extremely difficult to predict. Even on smaller scales and with less complexity of interacting processes, only very limited boundary conditions, i.e. a narrow range of atmospheric variability and land surface topography favouring the intended alteration, seem to justify weather modification. Moreover, as for systems reaching scales of large organized storms and hurricanes, required energy and control resources are well beyond existing capabilities. Consequently, the use of space technology for provision of better information on environmental change and integration of remote sensing data into weather and climate models forecasts is supported.

Norwegian Sea overflow variability and NE Atlantic surface hydrography during the past 150,000 years

The long-term variability of Norwegian Sea Overflow through the Faeroe Bank Channel and its relation to NE Atlantic surface hydrography is reconstructed based on sedimentological, micropalaeontological and stable isotope analysis, as well as AMS 14C dating, of a sediment core (ENAM-33) retrieved near the outlet of the channel. Additional palaeoceanographic information has been obtained from three nearby sediment cores (ENAM-30, -32, 94-13). Our results demonstrate enhanced circulation of Norwegian Sea Overflow Water (NSOW) at times of increased Sea Surface Temperature (SST), and a reduction or cessation of NSOW flow at times of low SST. During the Last Glacial Maximum (LGM), NSOW activity was at a minimum from about 22 ka to 16 ka. After the LGM, NSOW circulation was weak until a major flow pulse of NSOW occurred, dated at between 13.4 ka and 12.0 ka. Thereafter, NSOW flow was once again reduced. Renewed intensification of NSOW flow did not occur until after 9.8 ka, whereas a further increase in NSOW activity is observed after the early Holocene. The timing of both glacial–interglacial and deglacial NSOW variability is similar to the timing of changes in deep-water circulation reconstructed from cores from the open North Atlantic in previous studies. Whereas most of these studies involve the reconstruction of changes in the proportion of North Atlantic Deep Water (NADW) relative to southern-source deep waters, the lithology of the cores from near the Faeroe Bank Channel outlet provides a qualitative but direct indication of the strength of NSOW currents. This study confirms that the NADW changes observed in the North Atlantic are due to a reduction in NSOW, and cannot be attributed only to an increase in southern-source deep waters. Furthermore, our results indicate that NSOW flow through the Faeroe Bank Channel was not a source of Glacial North Atlantic Intermediate Water (GNAIW), and that a subpolar source for this water mass is likely.

The Avoidance of the Third Tone Sandhi in Mandarin Chinese

An optimality-theoretic analysis of third tone sandhi (TS)domains of Mandarin is proposed in preference to otherapproaches. This constraint-based analysis provides adescriptively better solution to questions such as why it ispossible for a preposition to resist tone sandhi in certainstructures, a long-standing problem in tone sandhi studies. Thepaper shows that this resistance to tone sandhi is dependent onboth syntactic structures and syntactic categories. In thisstudy, Mandarin tone sandhi domains are related to constituentstrength representations, which are direct mappings of syntacticstructures. An unspecified order of strong/weak values ofconstituent strength for a prepositional phrase is proposed. Todefine a TS domain, several constraints related to metricalfactors, constituent strength, the tone sandhi domain groupingdirection, and output condition are shown to interact with eachother. The optimal tone sandhi domain representation is alwaysthe one which violates the lowest-ranked constraints and violatesany single constraint to the least degree possible, compared toother representations. The avoidance of tone sandhi by anelement, whether it is a preposition or another category, is theresult of interactions of the constraints. The variability ofsurface tone patterns comes from more than one optimal output,from speaking rate or style, and from two possible kinds ofcompetition due to the unspecified constituent strength.

Composition and abundance of resident marsh-surface nekton: comparison between tidal freshwater and salt marshes in Virginia, USA

Previous research on intertidal nekton communities has identifiedimportant determinants of community structure and distribution; however, fewstudies have compared nekton utilization of disparate marsh habitats. Inthis study, abundance and distribution patterns of resident nekton werecompared between tidal freshwater marsh and salt marsh surfaces varying inflooding depth and duration. Nekton were collected in pit traps installedalong elevational transects at four marshes in coastal Virginia (twofreshwater, two saline) from April through November 1992–1993. Thedominant fish collected at all sites was the mummichog Fundulusheteroclitus. The daggerblade grass shrimp Palaemonetes pugio was thedominant nekton species collected at salt marsh sites, and was seasonallyabundant on tidal freshwater marshes. A positive correlation betweenflooding depth and nekton abundance was observed on salt marshes; anopposite pattern was observed on tidal freshwater marshes. Tidal floodingregime influences the abundance of resident nekton, however, the effect maybe confounded by other environmental variables, including variation insurface topography and seasonal presence or absence of submerged aquaticvegetation (SAV) in adjacent subtidal areas. In mid-Atlantic tidalfreshwater wetlands, SAV provides a predation refuge and forage site forearly life stages of marsh-dependent nekton, and several species utilizethis environment extensively. Salt marshes in this region generally lackdense SAV in adjacent subtidal creeks. Consequently, between-sitedifferences in species and size-specific marsh surface utilization byresident nekton were observed. Larvae and juveniles represented 79%and 59% of total fish collected at tidal freshwater and salt marshsites, respectively. The resident nekton communities of tidal freshwater andsalt marsh surfaces are characterized by a few ubiquitous species with broadenvironmental tolerances.

Satellite Observations during TOGA COARE: Large-Scale Descriptive Overview

Abstract The 1992/93 Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (COARE) was specifically designed to monitor multiscale interactions between the atmosphere and ocean over the western Pacific warm pool. To help meet this objective, satellite observations were used to augment the enhanced COARE conventional data array in both space and time. In this paper the authors present a descriptive overview of convective cloud variability and sea surface temperature during the four-month intensive observational period (IOP) as revealed by satellite. Time series of Geostationary Meteorological Satellite infrared brightness temperatures are evaluated at selected equatorial locations in the western Pacific and eastern Indian Oceans. Intraseasonal modes of transient convection/cloudiness are revealed, with two eastward-propagating Madden-Julian oscillations identified. Spectral analysis on the time series data indicates that higher-frequency variations in regional convective activity ar...

Quality of ocean variability results from satellite altimetry

Abstract One year of Geosat altimeter data is used for a comparison among three different processing techniques for the determination of mesoscale ocean currents. The observations, like sea surface variability and sea surface anomaly time series, yield a valuable contribution to all kinds of oceanographic studies. The article presents an a‐priori estimate of the feasible spatial and temporal resolutions of the observations by validating the different processing techniques and comparing the results. It shows an excellent correlation between the different sea surface anomaly field solutions. For the Agulhas Retroflection area it was found that the standard deviation of the obtained relative sea level may amount to up to 4 cm and that the average correlation is better than 0.90 (±0.04). The overall quality of the results obtained was shown to depend on the mesoscale signal strength and therefore differs for each region. This nonisotropic behavior of the correlation between the sea surface anomaly fields is s...

Range‐dependent acoustic propagation in a channel with ocean variability: A comparison of observations and modeled results

The skewness of the distribution of acoustic intensities due to multiple scattering [T. E. Ewart, J. Acoust. Soc. Am. 84, 1490–1498 (1989)] and the possible obliteration of fine detail diffraction effects by random phase modulation indicate that it may never be appropriate to decouple variability from calculations of a mean acoustic field. If so, this has serious implications for the (often used) approach of adding on (or even ignoring) variability to the mean‐field results of deterministic modeling. In October 1989, an experiment was conducted in the North Sea by SACLANTCEN, Italy in collaboration with FWG, Germany to simultaneously observe the acoustic field and oceanographic condition in a weak acoustic surface channel. The channel exhibited volume variability and appreciable surface roughness. A 50‐m depth source was towed away from a stationary 62‐m vertical array, transmitting 40‐ms cw pulses at 800, 1000, and 1500 Hz. Measurements were taken out to a range of 35 km and back. A simultaneous oceanogr...

Variation of Chemical Concentration in Surface-Coated and Tableted Grain Baits

Liquid scintillation spectrometry was used to determine the quantity of recovered carbon14labelled Mesurol (4-[methylthio]-3,S-xylyl N-methylcarbamate) from individual baits. The six grain baits tested were cracked corn, wheat kernels, and oat groats, each formulated as surface-coated baits and as tablets (ground grain mixed with the chemical and tableted). The concentration of Mesurol on the surface-coated baits was highly variable, with coefficients of variation (CV) ranging from 21.0 percent (wheat) to 48.] percent (cracked corn); Mesurol in individual cracked corn baits ranged from 99-532 ,ug. Such variation could easily explain erratic results in field baiting programs or laboratory tests. The tableted baits were more uniform (CV, 4.6-8.0 percent; greatest range, 274-360 yg) and are recommended for baiting situations where chemical concentration is critical. VARIATION IN SURFACE_COATED AND TABLETED BAITS * Bullard 925 , AND L. L. DICKSON. 1967. Thern10regulation in the desert iguana, Dipsosaurus dorsalis. Science 156 ( 3783 ) :1757-59. , AND T. P. SOUTHWORTH. 1967. Body temperature fluctuations in the Northern elephant seal. J. Mammal. 48 ( 3 ): 484-485 . Received for publication March 23, 1970. of untethered dolphin recorded by ingested radio transmitter. Science 144(3621):864-866. 1967. Bio-medical telemetry. New York, John Wiley, Inc. 388pp. McGINNIs, S. M. 1968. Biotelemetry in pinipeds; in the behavior and physiology of pinipeds. Appleton-Century-Croft, New York. 411pp. tions. The present experiment was conducted to determine the extent of such variation in grain baits for animal damage control by comparing the chemical concentration in three kinds of surface-coated baits, all prepared in the same manner, with that in bait tablets made from the same materials. I thank Ann H. Jones for editorial assistance, J. L. Oldemeyer for statistical assistance, and R. R. Bott for technical assistance irs the analyses. My thanks also to the co-workers who helped in the bait formula-