bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature fine‐structure of Lake Michigan hypolimnion1,2
Authors: Marmorino George O. , Danos Savas C. , Maki James S.
Published: March 2010

High‐resolution temperature profiles from the hypolimnior of Lake Michigan in June and August 1978 showed the frequent occurrence of intrusive layers of thickness 10 m or less. Anomalously warm layers (ΔT ≲ 0.1°C) seemed to extend horizontally for ≳0.5 km and to persist at one location for day. Since temperatures were above maximum density values, these layers would have been hydrostatically unstable were it not for observed stabilizing gradients of dissolved silica. Interleaving of the layers, shear‐induced turbulence, and stirring at the bottom resulted in various small‐scale temperature structures. After an intense coastal upwelling event, a bottom layer 5‐m thick was observed along the 100‐m isobath in which temperatures and silica concentrations were nearly uniform and in which a value of at least 0.1 crn2·s−1 was calculated for the vertical eddy diffusivity.
Annual production and drift of the stream amphipod Gammarus pseudolimnaeus in Valley Creek, Minnesota1
Authors: Waters Thomas F. , Hokenstrom Jay C.
Published: March 2010

Annual production and drift of Gammarus pseudolimnaeus were measured in a 100‐m section of Valley Creek for the 5‐year period 1968–1973. Production was estimated by the procedure previously termed the “Hynes method,” herein proposed to be termed the “size‐frequency method.” Annual production was 271 and 231 kg·ha−1 (dry wt) in the first 2 years but declined subsequently to a low of 64 kg·ha−1, apparently the result of a severe siltation. Annual mean daily drift corresponded, being high at 41 and 46 g·d−1·m−3 s−1 in the first 2 years, but only about 7 and 11 in the last 2 years. Mean annual standing stock was also high in the first 2 years (47 and 35 kg·ha−1) but substantially lower n the last 2 years (11 and 17); mean annual density was 7,176 and 6,849·m−2 in the first 2 years and 1,586 and 2,363·m−2 in the last 2 years. Annual P:B ratios were 5.7–6.6 over the 5‐year period, with an average of 6.0.
Photosynthetic bacterial production in lakes: The effects of light intensity1
Authors: Parkin T. B. , Brock T. D.
Published: March 2010

Primary production was measured in six lakes supporting populations of photosynthetic sulfur bacteria. Bacteriochlorophyll concentrations (Behl a + Bchl c) ranged from 11.1 to 630 mg·m−3. The photosynthetic sulfur bacteria accounted for 0.26–6.3% of the total daily production in the lakes. The percentage of photosynthetic bacterial production of total production in the lakes was .not correlated with either sulfide concentration or bacteriochlorophyll concentration hut was related to light intensity.
Measurement of planktonic bacterial production in an oligotrophic lake1
Authors: Jordan Marilyn J. , Likens Gene E.
Published: March 2010

Planktonic heterotrophic bacterial production in Mirror Lake (New Hampshire) was estimated by several different methods. Production ranged between 3 and 8 g C·m−2 yr−1 based on organic C fluxes and the sum of bacterial losses. The close agreement with the estimate of 6.5 ± 1.8 (x̄ ± SE) obtained by the 35SO4 method (in which bacterial S uptake was multiplied by a C:S ratio of 50) supports the validity of using this method in aerobic freshwaters. Only 16% of the total SO4 uptake was due to bacteria as determined by differential filtration with Nuclepore filters. Production was overestimated (20 g C·m−2·yr−1) if bacterial dark CO2‐C uptake (58% of total dark CO2 C uptake) was taken as 6% of heterotrophic bacterial production. Doubling times for heterotrophic planktonic bacteria ranged from 1.2 days (September) to >100 days (February). The annual C flux through planktonic bacteria, including respiration, represented 11–31% of the total autochthonous plus allochthonous organic C inputs to the lake.
Relation between particle size selection and clearance in suspension‐feeding ciliates
Authors: Fenchel Tom
Published: March 2010

Suspension‐feeding, ciliated protozoans retain particles by sieving the feeding currents through ciliary organelles and show well‐defined size spectra with respect to the particles retained and ingested. When different species of ciliates are compared, clearance is correlated with the particle size most efficiently retained. Thus, species specialized on particles of bacterial dimensions (0.2–1 µm) have a strongly reduced clearance, due to a decreased rate of water propulsion through the filter, from that of species specialized on larger food particles. It is suggested that this is related to the increased resistance to water flow in filters with a decreasing porosity, since cilia can only generate a small hydrostatic pressure. Ciliary suspension feeders specialized on small particles have relatively high requirements with respect to the minimum food particle concentration; they could not maintain populations at bacterial concentrations typical of offshore waters.
Filmed observations of filter feeding in the marine planktonic copepod Acartia clausii
Authors: Rosenberg Gene G.
Published: March 2010

Filter feeding by Acartia clausii was studied from high‐speed motion pictures (250 frames·s−1) of the copepods grazing in natural seawater and in suspensions of Skeletonema costatum. Feeding was intermittent, with feeding bouts ranging in length from 90 to 1,000 ms in natural particle suspensions. During feeding, the mouthparts vibrated at about 60 Hz. Acartia also used its thoracic legs in feeding to supplement the filtering action of the maxillae.
Induced swarming in the predatory copepod Heterocope septentrionalis1
Authors: Hebert Paul D. N. , Good Allen G. , Mort Mona A.
Published: March 2010

Adults of the predatory calanoid copepod Heterocope septentrionalis are not randomly distributed in natural habitats: they aggregate above areas of pale substrate. When panels of yellow or white plastic were placed in ponds near Churchill, Manitoba, swarms with up to 300× the ambient density formed. These aggregations were most dense when light intensity was high and wind strength low. The attraction to pale substrates was not transient; adults showed the response through their life‐span. From an adaptive standpoint, the behavior may enhance the frequency of mating encounters. The occurrence of swarming provides a simple way of manipulating predator densities in these habitats.
Determination of total dissolved nitrogen in natural waters1
Authors: Solórzano Lucia , Sharp Jonathan H.
Published: March 2010

A procedure is presented for routine analysis of total nitrogen in solution which is similar to published methods using oxidation by potassium persulfate. Careful attention to pH, alkalinity, the neutralizing buffer, reaction vessels, and dilution factors have proved necessary. This modified method is acceptable for samples from fresh to oceanic waters, is accurate for organic compounds tested, has a maximum capability of 40 µM nitrogen in undiluted samples, and has a mid‐range precision of ±2%.
Determination of total dissolved phosphorus and particulate phosphorus in natural waters1
Authors: Solórzano Lucia , Sharp Jonathan H.
Published: March 2010

Procedures are presented for separate analyses of total dissolved phosphorus and total particulate phosphorus in natural waters. The method for both procedures involves drying a sample with magnesium sulfate and baking the residue at a high temperature to decompose organic phosphorus compounds. The residue is then treated with hydrochloric acid to hydrolyze polyphosphates and the orthophosphate is measured by the molybdate method. The method gives 100% recovery with refractory phosphorus compounds, is usable on undiluted samples with up to 18 µmol of phosphorus per liter (6 µg P per sample), and has a mid‐range precision of ±1%.
A tidal‐powered water sampler1
Authors: Hayes D. W. , Harris S. D. , Stoughton R. S.
Published: March 2010

A tidal‐powered compositing water sampler has been designed to operate over a wide range of tides. It can sample water over long periods without attention and can be made from inexpensive hardware components and two check valves. The working principle of the sampler is to use the reduction of pressure by the falling tide and the stored pressure from the previous high tide to pump water into a collection bottle. The sampler can produce a constant volume of water per tidal cycle over a tidal range of 2–4 m.
Computation of confidence intervals for the size‐frequency (Hynes) method of estimating secondary production1
Authors: Krueger Charles C. , Martin Frank B.
Published: March 2010

An estimator of variance is described for production values calculated by the size‐frequency (Hynes) method. The number of sampling dates is identified as having an important influence on the variance estimate. A geometric mean is proposed to estimate the average weight of individuals when lost between size classes. In an example calculation, Ephemerella dorothea (Ephemeroptera) from North Branch Creek, Minnesota, had an annual production value of 8.5 g·m−2 wet and an approximate 95% confidence interval of 7.0–10.0. Similar calculations for Baetis sp. (Ephemeroptera) from the same river yielded an annual production value of 4.7 g·m−2 wet with a confidence interval of 3.6–5.8. Significant differences in annual production thus exist between these mayflies.
Gas exchange rates for three closed‐basin lakes1
Authors: Peng Tsung-Hung , Broecker Wallace
Published: March 2010

Long term monitoring of the 14C:12C ratio in three closed‐basin lakes in the western United States has resulted in reliable estimates of the mean CO2 invasion rates. When normalized to sea level pressure the results are 6 mol·m−2·yr−1 for Pyramid Lake, 17 for Walker Lake, and 38 for Mono Lake. Except for Mono Lake, these bomb 14C‐derived invasion rates are consistent with those derived from the distribution of natural radiocarbon. The big difference in the invasion rates estimated for Mono Lake by the two methods is attributed to the influx of 14C‐free spring waters to the lake. Possible causes for the difference in CO2 invasion rates among the three lakes are wind velocity, salinity, and pH.
Adsorption of phosphate in anoxic marine sediments1
Authors: Krom Michael D. , Berner Robert A.
Published: March 2010

The adsorption of dissolved phosphate in anoxic marine sediments has been investigated in samples of mud from two locations in Long Island Sound kept under strictly anoxic conditions. Kinetic experiments showed that desorption is more rapid than adsorption, but that both reach equilibrium within 24 h. The process of adsorption of phosphate can be described by a simple linear isotherm: the dimensionless in situ adsorption coefficient (K) determined from four separate runs on mud from the FOAM site was 1.7 ± 0.2; for sediment from the NWC site it was 1.9. Diffusion measurements provide independent experimental confirmation of this value for K. These values of K are much lower than those in oxic sediments because the iron oxyhydroxides which are important in the adsorption of phosphate in oxic sediments are converted to iron sulfides in anoxic muds.
Microelectrophoretic properties of natural surface‐active organic matter in coastal seawater
Authors: Hunter K.A.
Published: March 2010

Measurements by the technique of particle electrophoresis reveal that different well characterized solid surfaces freshly exposed to seawater become covered by a tenacious film of natural surface‐active organic matter which dominates their subsequent surface chemistry. The dependence of electrophoretic mobility (ue) on pH and metal ion concentration (pM) indicates that carboxylic acid (−COOH) and phenolic (−OH) groups are the major ionizable functional groups in the organic film exposed to the solution. Detailed treatment of the data on ue vs. pH and ue vs. pM allows calculation of intrinsic equilibrium constants for the dissociation of surface carboxylic acid groups and the complexation of metal ions by the organic film. The results obtained are in substantial agreement with data derived from more classical potentiometric titrations of marine and freshwater organic matter isolated by adsorption or ultrafiltration methods.
Plutonium uptake by marine phytoplankton in culture1
Authors: Fisher Nicholas S. , Olson Brenda L. , Bowens Vaughan T.
Published: March 2010

At environmentally realistic atom conscentrations 237Pu tracer was used to examine Pu uptake by unialgal cultures of Thalassiosira pseudonana (live and dead), Thalassiosira sp., and Platymonas sp., as well as by glass particles. Live or dead cells and glass particles accumulated Pu at similar rates, indicating that initial uptake was a passive phenomenon. Uptake was strongly affected by the nature of particle surfaces, but much less by composition of the media. Cells from rapidly growing cultures took up more Pu than did those from late log or senescent cultures. Acid‐washed glass took up more Pu, faster, than did unwashed glass. Cells accumulated more Pu from UV‐treated seawater than from seawater untreated or enriched with f/50‐level EDTA or f/50 vitamins; from complete f/50 medium uptake was even less, as with f/50 trace metals + EDTA. After a short uptake Pu was 25% removable in tracer‐free media, but after 3 days of uptake none was removable in seawater or exometabolite media, and only 15% in f/50‐level EDTA. The data support the hypothesis that Pu in marine environments associates with suspended particles that could act as vertical vectors for this element.
Phytoplankton accumulation in Langmuir cells1
Authors: Evans Geoffrey T. , Taylor F. J. R.
Published: March 2010

We investigate the distribution of phytoplankton in Langmuir circulations, under various assumptions about the motion of the water and of phytoplankton through the water. The details of water movement appear to be relatively unimportant compared to the details of phytoplankton movement: Stommel’s analysis of a very simple model is easily extended to more realistic descriptions of Langmuir circulation, hut it break down if plankton velocities are not constant. We discuss some possible ecological consequences, especially concerning red tides.
1
Authors: LaZerte Bruce D.
Published: March 2010

The internal seiche structure of a small, shallow lake (Frains Lake, Michigan) is shown to be dominated by the higher order vertical modes. The resonant frequencies and the vertical velocity profiles of each mode were predicted from observed temperature profiles. The observed resonant frequencies and observed phase shifts in the velocity profiles of each mode corresponded closely to those predicted. Although the relative amplitude of each mode varied with depth, the higher modes (up to 7–10th) dominated an the fundamental mode was transitory.
In situ measurement of the settling velocity of organic carbon particles and 10 species of phytoplankton
Authors: Burns N. M. , Rosa F.
Published: March 2010

An in situ method of simultaneously measuring the settling velocity of three size ranges of particulate organic carbon (POC) particles and 10 species of phytoplankton is described. The measurements took 2 h and were done at four different periods during the diurnal cycle. The POC fluxes of particles in the size ranges 1‐10 µ, 10–64 µ, and >64 µ were about equal for each size range and showed very little diurnal variation. In contrast, the phytoplankton showed considerable response to the varying light intensities of a day. The flagellates migrated downward at sunset; a species of diatom settled more slowly during daylight than at night; a blue‐green species showed maximum buoyance at midnight and some green species changed from downward sinking on a bright day to upward movement on a dull day.
Carbon budget of a marine phytoplankton‐herbivore system with carbon‐14 as a tracer1
Authors: Copping Andrea E. , Lorenzen Carl J.
Published: March 2010

Adult female and stage V Calanus pacificus were fed 14C‐labeled phytoplankton in the laboratory in the form of monospecific cultures and natural populations. A carbon budget was constructed by following the 14C activity and the specific activity, over 48 h, in the phytoplankton, copepod, dissolved organic, dissolved inorganic, and fecal carbon compartments.

The average incorporation of carbon into the copepod’s body was 45% of the phytoplankton carbon available. Of the phytoplankton carbon, 27% appeared as dissolved organic carbon, 24% as dissolved inorganic carbon, and 3–4% in the form of fecal pellets. All of the tracer was recovered at the end of the experiments. The specific activity of the phytoplankton compartment was constant throughout each experiment. The other compartments had initial specific activities of zero, or close to zero, and increased throughout the experiment. In most experiments, the copepod specific activity equalled that of the phytoplankton at the end of 48 h, while the dissolved organic carbon, dissolved inorganic carbon, and fecal specific activities remained well below that of the phytoplankton.
Metabolic expenditures in Chaoborus larvae1
Authors: Giguère Louis A.
Published: March 2010

The energy consumption of 4th instar larvae of Chaoborus trivittatus of two different ages was determined in a respirometer. Measurements included energy consumption of fed larvae at 13° and 21°C, as well as an estimate of the cost of process: ng food or specific dynamic action (equals the metabolic rate of starved larvae × 0.369). The energy costs of swimming and of attacking prey, also measured experimentally, were 0.07 and 0:57 mJ·motion−1. These estimates represent the negative terms of the energy budget of this ambush predator.
High frequency radar measurements of tidal currents flowing through San Pablo Strait, San Francisco Bay1
Authors: Maresca Joseph W. , Padden Robin R. , Cheng Ralph Ta‐shun , Seibel Erwin
Published: March 2010

High frequency (HF) radar measurements of the surface current averaged over the upper 0.5 m in San Pablo Strait were compared with current meter measurements of the subsurface current made at 9.4 m below mean lower low water (MLLW) over two 12.4‐h tidal cycles. After averaging the radar and current meter data over two tidal cycles, a southerly (ebbing direction) surface current of 32 cm·s−1 was deduced from the radar measurements and a northerly (flooding direction) subsurface current of 7 cm·s−1 from the current meter measurements. This nontidal flow is maintained by freshwater discharge from the Sacramento–San Joaquin Rivers into Suisun and San Pablo Bays. The radar measurement technique provides quantitative estimates of the surface currents that previously were determined only from surface drifter studies.
A sequencing sediment trap for time‐series studies of fragile particles1,2
Authors: Jannasch Hans W. , Zafiriou Oliver C. , Farrington John W.
Published: March 2010

A versatile sediment trap for time‐series studies has been developed and tested in Buzzards Bay, Massachusetts, and to 600 atm pressure. It collects up to eight samples at widely variable intervals, preserves them if desired in a viscous aqueous medium, and can be redeployed rapidly.
The use of DAPI for identifying and counting aquatic microflora1
Authors: Porter Karen G. , Feig Yvette S.
Published: March 2010

A highly specific and sensitive fluorescing DNA stain, 4′6‐diamidino‐2‐phenylindole (DAPI) was compared with acridine orange (AO) for counting aquatic microflora. Use of DAPI improved visualization and counting of <1‐µm bacteria and blue‐green algae in seston‐rich samples and extended sample storage to at least 24 weeks.
Enhanced detection of bacteria in natural environments by fluorochrome staining of DNA1
Authors: Coleman Annette W.
Published: March 2010

The DNA‐staining fluorochromes 4′6‐diamidino‐2‐phenylindole (DAPI) and mithramycin, when used in conjunction with epi‐illumination fluorescence microscopy, readily reveal the presence of bacteria, thus simplifying the detection of bacterial contaminants in allegedly axenic laboratory cultures of eucaryote cells. Both gram‐negative and gram‐positive cells are stained, and aqueous solutions of the dyes penetrate living as well as fixed cells. The use of an epi‐illumination system for fluorescence microscopy makes it possible to scan the microflora epiphytic on material collected from freshwater or marine environments, even when the thickness of the material renders both phase and Nomarski optics inadequate.
Containment effects in copepod grazing experiments: A plea to end the black box approach1
Authors: Roman Michael R. , Rublee Parke A.
Published: March 2010

Containment effects from enclosing unfiltered seawater and copepods in 500‐ml jars to estimate grazing rate were examined six times during 48‐h incubations. Crazing rates decreased rapidly for the first 3 h (up to 50%) and then continued to decrease at slower rates. The number of bacteria increased in both control and experimental jars. Variable but significant changes were found in the size distribution of particles and concentrations of adenosine triphosphate and chlorophyll a. Ammonia concentrations were higher in jars with copepods. After 24 h, grazing rates calculated from control jars with NH4+ additions to simulate copepod excretion were about twice those calculated from unamended controls. The grazers removed 2% of the 3‐5‐µm particles compared to unamended controls and 17% compared to control jars plus NH4+.
Food limitation of egg production by a marine, planktonic copepod in the sea off southern California1
Authors: Checkley David M.
Published: March 2010

The in situ rate of egg production (B) and female size of Paracalanus parvus, a particle‐grazing copepod, water temperature, and the concentrations of chlorophyll a and particulate nitrogen were measured in 31 collections from the euphotic zone of the sea off southern California. B was correlated positively with chlorophyll a and female size and negatively with temperature. A multiple regression of log B on chlorophyll a, particulate nitrogen, female size, and temperature accounts for 44% of the variation in log B.B was predicted best by an empirical function of food concentration when the food available in nature was considered to be phytoplankton rather than of all types of particulate matter >5 µ.

An index of immediate food limitation was derived from laboratory data as a function of food concentration. When applied to extensive measurements of chlorophyll a in the euphotic zone, this index indicates that Paracalanus was often food limited and that food limitation increased along an onshore‐offshore transect. Paracalanus was rarely food limited in Santa Monica Bay.
Volatile organic compounds in seawater from the Peru upwelling region1,2
Authors: Gschwend Philip , Zafiriou Oliver C. , Gagosian Robert B.
Published: March 2010

The concentrations and distributions of individual volatile organic compounds in seawater were determined at six stations in the upwelling region off the coast of Peru by vapor phase stripping, glass capillary gas chromatography, and gas chromatography‐mass spectrometry techniques. Saturated and unsaturated hydrocarbons, alkylated benzenes, and aldehydes were found. Individual compound concentrations varied from <2 ng·kg−1 to about 60 ng·kg−1 All of the volatile compounds were present at higher concentrations in surface than in deeper waters, but each class of compounds had a unique horizontal distribution. Spatial distributions and correlations with hydrographic data suggest possible sources and transformations.
Dimethylsulfoxide in marine and freshwaters
Authors: Andreae Meinart O.
Published: March 2010

Dimethylsulfoxide (DMSO) occurs at concentrations of >10 nmol·liter−1 in the surface ocean and in rivers and lakes, and is not detected (<1 nmol·liter below the euphotic zone. Its concentration correlates well with indicators of primary productivity and with dimethylarsinate, an algal excretion product. Seven of eight pure, axenic cultures of marine planktonic algae produced significant amounts of DMSO. These findings suggest that DMSO is associated with phytoplankton activity in surface waters.

DMSO occurs in rain ( ≈5 nmol·liter−1) from marine air masses, suggesting that DMSO, dimethylsulfide, or both participate in the transfer of sulfur between ocean and atmosphere.
Nitrate and ammonium uptake in Antarctic waters1
Authors: Olson Robert J.
Published: March 2010

Nitrate and ammonium uptake rates were measured by the 15N tracer technique in Antarctic waters. The ratio

urn:x-wiley:00243590:media:lno19802561064:lno19802561064-math-0001

averaged 0.54 in the Scotia Sea in early spring and 0.40 in the Ross Sea in summer, indicating that NO3− and NH4+ contribute about equally to primary production in these regions and that a large proportion of the primary production is exported from the surface layers. Uptake rates in laboratory experiments increased with increasing temperature and the relative uptake of NH4+ was positively correlated with increasing mean ambient NH4+ concentration and depth in the water column.
Transient situations in nitrate assimilation by marine diatoms. 1. Changes in uptake parameters during nitrogen starvation1
Authors: Collos Yves
Published: March 2010

The parameters of nitrate uptake by nitrogen‐limited and nonlimited cells of Phaeodactylum tricornutum change extensively during nitrate starvation. The saturated uptake rate, affinity constant, and nitrogen cell content decrease by half to three‐fourths in 3 days, while the cells remain metabolically active. Under continuous light, the absolute uptake rate goes through a maximum after 3–5 h of starvation, then decreases significantly. Upon re‐exposure to nitrate, nonlinear uptake is observed if the cells have been deprived of nitrate for more than 24 h. After a lag time which is related to the duration of the previous starvation phase, a shift‐up in saturated uptake rate occurs, leading to recovery of the initial rate within hours. The direction of change in the specific uptake rate depends on the physiological state of the cells before the starvation phase. The relationship between specific uptake rate and nitrogen cell content of nitrogen‐starved cultures, although in contrast to that found with nitrogen‐limited cultures, has the advantage of better describing results from field studies: low uptake rates and affinity constants in oligotrophic waters and high values in eutrophic waters. These findings have implications within the context of the theory of nutrient limitation and, more generally, in relation to the use of the Michaelis‐Menten equation in modeling nutrient uptake by marine phytoplankton.
Comparison of continuous phytoplankton records with the diatom stratigraphy in the recent sediments of Blelham Tarn
Authors: Haworth Elizabeth Y.
Published: March 2010

The stratigraphy of diatom remains in the sediment of Blelham Tarn, in the English Lake District, has been compared with population data collected by J. W. G. Lund over about 35 years. There is sufficient correlation for the production of an algal‐based time scale for recently accumulated sediments which can be difficult to date precisely. Although there can be considerable variation in the pattern of deposition at different sites in the lake they can all be correlated with the written record.
Chromium species in the Columbia River and estuary1
Authors: Cranston R. E. , Murray J. W.
Published: March 2010

Columbia River and estuary samples were analyzed to determine dissolved Cr species and particulate Cr concentrations. Flocculation and spike experiments were done to elucidate the processes controlling the distribution of Cr. River water contained an average of 3.2 nM dissolved Cr (98% as CrO42−) and 1.8 nM particulate Cr; estuary samples contained an average of 2.4 nM dissolved Cr and 2.8 nM particulate Cr. Dilution plots suggest that CrO42− is conservative in the estuary, while flocculation processes increase the Cr(particulate) and Cr(III) concentrations. Up to 28% of the dissolved Cr in river water could be removed by adsorption onto or flocculation with freshly formed particles. Over 70% of added Cr(III) was removed by adsorption onto particles and container walls within 1 h; CrO42− spikes behaved conservatively.
Diurnal and seasonal variations in the growth of a staghorn coral measured by time‐lapse photography
Authors: Barnes D. J. , Crossland C. J.
Published: March 2010

Branch elongation in a staghorn coral was measured by comparing photographs taken at 6‐h intervals. The data suggest seasonal changes in daily extension. Although photosynthesis by symbiotic algae considerably increases skeletal deposition in reef‐building corals, the nighttime extension was similar to, or greater than, the daytime extension.
A simple maximum‐minimum salinity sampler
Authors: Walker Terriss
Published: March 2010

Bottles are described that collect water samples of maximum and minimum salinity when placed in a temporally varying estuary.
Validation of manual muscle testing and a subset of eight muscles for adult and juvenile idiopathic inflammatory myopathies
Authors: Rider Lisa G. , Koziol Deloris , Giannini Edward H. , Jain Minal S. , Smith Michaele R. , Whitney‐Mahoney Kristi , Feldman Brian M. , Wright Susan J. , Lindsley Carol B. , Pachman Lauren M. , Villalba Maria L. , Lovell Daniel J. , Bowyer Suzanne L. , Plotz Paul H. , Miller Frederick W. , Hicks Jeanne E.
Published: March 2010

Objective

To validate manual muscle testing (MMT) for strength assessment in juvenile and adult dermatomyositis (DM) and polymyositis (PM).

Methods

Patients with PM/DM (73 children and 45 adults) were assessed at baseline and reevaluated 6–9 months later. We compared Total MMT (a group of 24 proximal, distal, and axial muscles) and Proximal MMT (7 proximal muscle groups) tested bilaterally on a 0–10 scale with 144 subsets of 6 and 96 subsets of 8 muscle groups tested unilaterally. Expert consensus was used to rank the best abbreviated MMT subsets for face validity and ease of assessment.

Results

The Total, Proximal, and best MMT subsets had excellent internal reliability (Total MMT rs = 0.91–0.98), and consistency (Cronbach's α = 0.78–0.97). Inter‐ and intrarater reliability were acceptable (Kendall's W 0.68–0.76, rs = 0.84–0.95). MMT subset scores correlated highly with Total and Proximal MMT scores and with the Childhood Myositis Assessment Scale, and correlated moderately with physician global activity, functional disability, magnetic resonance imaging, and axial and distal MMT scores, and, in adults, with creatine kinase level. The standardized response mean for Total MMT was 0.56 in juveniles and 0.75 in adults. Consensus was reached to use a subset of 8 muscles (neck flexors, deltoids, biceps, wrist extensors, gluteus maximus and medius, quadriceps, and ankle dorsiflexors) that performed as well as the Total and Proximal MMT, and had good face validity and ease of assessment.

Conclusion

These findings aid in standardizing the use of MMT for assessing strength as an outcome measure for myositis.
Risk of revision for infection in primary total hip and knee arthroplasty in patients with rheumatoid arthritis compared with osteoarthritis: A prospective, population‐based study on 108,786 hip and knee joint arthroplasties from the Norwegian Arthroplasty Register
Authors: Schrama Johannes C. , Espehaug Birgitte , Hallan Geir , Engesæter Lars B. , Furnes Ove , Havelin Leif I. , Fevang Bjorg‐Tilde S.
Published: March 2010

Objective

To compare differences in the risk of revision for infection and changes in risk over time and in time from primary surgery to revision for infection after total hip replacement (THR) and total knee replacement (TKR) in rheumatoid arthritis (RA) and osteoarthritis (OA) patients.

Methods

In the Norwegian Arthroplasty Register, 6,629 and 102,157 primary total joint replacements in patients with RA and OA, respectively, were identified from 1987 (1994 for knees) until 2008. Survival analyses with revision due to infection as the end point were performed using Kaplan‐Meier methods for constructing survival curves and multiple Cox regression to calculate relative risk (RR) estimates for diagnosis, age, sex, and year of primary surgery. An extended Cox model was used to estimate RR within different followup intervals.

Results

RA patients with TKR had a 1.6 times higher risk of revision for infection than OA patients, whereas there was no difference in the THRs. In the THRs, we found a higher risk of revision for infection from 2001 onward, whereas the development for TKRs was the opposite. These time effects affected the RA and OA groups equally. The risk of revision for infection from 6 years postoperatively on was higher in RA patients.

Conclusion

The overall risk of revision for infection after TKR was higher in RA patients. The risk of late infection leading to revision of the TKR and THR was higher in RA patients than in OA patients. After the year 2000, the RR of revision for infection in RA compared with OA remained unchanged.
Prevalence of specific types of arthritis and other rheumatic conditions in the ambulatory health care system in the United States, 2001–2005
Authors: Sacks Jeffrey J. , Luo Yao‐Hua , Helmick Charles G.
Published: March 2010

Objective

To estimate the overall prevalence of medically‐treated arthritis and other rheumatic conditions (AORC) for adults, the prevalence of specific medically‐treated conditions, and the overall annual number of visits for these conditions in the ambulatory health care system.

Methods

We used data from the 2001–2005 National Ambulatory Medical Care Survey and 2001–2005 National Hospital Ambulatory Medical Care Survey to estimate annual ambulatory health care visits for the International Classification of Diseases, Ninth Revision, Clinical Modification codes thought to represent AORC. Using data on the number of prior annual visits per patient per condition, we converted the visit estimates into prevalence estimates of adults age ≥18 years with medically‐treated AORC overall and for specific conditions.

Results

The overall prevalence estimate of adults with medically‐treated AORC was 29,150,000 adults (95% confidence interval [95% CI] 26,473,000–31,826,000) and accounted for 77,887,300 ambulatory care visits (95% CI 71,266,000–84,508,000). The top 5 most prevalent conditions were osteoarthritis and allied disorders, unspecified joint disorders, peripheral enthesopathies, unspecified arthropathies, and other disorders of synovium, tendon, or bursa.

Conclusion

The advantage of our approach is that it uses existing rather than expensive new surveys for tracking the prevalence of medically‐treated AORC overall and tracking the prevalence of difficult to measure specific conditions. The estimates are data based and national in scope. More relevantly, they better estimate the numbers of persons whose AORC impacts on the ambulatory health care system.
Predictors of single‐leg standing balance in individuals with medial knee osteoarthritis
Authors: Hunt Michael A. , McManus Fiona J. , Hinman Rana S. , Bennell Kim L.
Published: March 2010

Objective

To identify factors related to single‐leg standing balance in individuals with medial compartment knee osteoarthritis (OA).

Methods

This cross‐sectional study assessed clinical, demographic, and biomechanical measures in 57 individuals and their relationships with single‐leg standing balance. Differences in age, mass, symptoms, knee pain, radiographic severity, lower extremity alignment, and hip and knee extension as well as hip abduction torques were compared between those who could and could not perform 3 trials of single‐leg standing balance. Multiple regression was used to identify predictors of center of pressure (COP) path length in those who could complete the task.

Results

Thirty‐four individuals (60%) successfully completed all 3 single‐leg standing balance trials and were significantly younger (P = 0.003) than those who could not. No other variable was significantly different between the groups. Disease severity, number of painful knees, lower extremity alignment, pain intensity, and quadriceps torque were all significant predictors of COP path length. Specifically, better single‐leg standing balance (smaller COP path length) was related to more severe radiographic changes and stronger quadriceps, those with bilateral symptoms, and to less varus malalignment and knee pain.

Conclusion

Single‐leg standing balance in those with medial knee OA is related to the modifiable factors lower extremity alignment, knee pain, and quadriceps strength. Given the reduced balancing ability in this patient population, interventions targeting these factors are necessary.
Self‐reported knee and foot alignments in early adult life and risk of osteoarthritis
Authors: McWilliams Daniel F. , Doherty Sally , Maciewicz Rose A. , Muir Kenneth R. , Zhang Weiya , Doherty Michael
Published: March 2010

Objective

To determine whether self‐reported early adult life malalignment of knees or feet are risk factors for knee or hip osteoarthritis (OA).

Methods

Participants in the Genetics of Osteoarthritis and Lifestyle case–control database were sent a questionnaire (n = 3,022) containing line‐drawing instruments for self‐reported knee and foot alignment at ages 20–29 years. Respondents were categorized as having straight, valgus, or varus knee, and straight, toe‐in, or toe‐out feet. Radiographic criteria were used to define current isolated knee or hip OA, combined knee and hip OA, or non‐OA controls. Odds ratios (ORs), adjusted ORs, and 95% confidence intervals (95% CIs) were calculated and logistic regression was performed.

Results

The response rate was 72%; 87.5% of responders (n = 1,901) completed the alignment questions. Increased risk of isolated knee OA occurred with early adult varus (adjusted OR 5.16, 95% CI 2.87–9.41) and valgus knees (adjusted OR 3.16, 95% CI 1.04–9.64). The positive association between knee OA and toe‐in foot was explained by varus knee. There was an increased risk of combined knee/hip OA from varus (adjusted OR 4.52, 95% CI 2.39–8.53) and valgus knees (adjusted OR 3.07, 95% CI 0.99–9.54). Varus knee was associated with risk of medial tibiofemoral OA, whereas valgus knee was associated with risk of lateral tibiofemoral and lateral patellofemoral OA. Toe‐out foot was associated with reduced medial patellofemoral OA. For knee OA, a multiplicative interaction analysis between occupational risks and varus/valgus yielded an ORint of 3.20 (95% CI 1.08–9.49).

Conclusion

Constitutional alignment of the leg in terms of varus or valgus knee or foot rotation may be a significant factor in determining development and distribution of knee but not hip OA.
Accurate detection of changes in disease activity in primary Sjögren's syndrome by the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index
Authors: Seror Raphaèle , Mariette Xavier , Bowman Simon , Baron Gabriel , Gottenberg Jacques Eric , Boostma Hendrika , Theander Elke , Tzioufas Athanasios , Vitali Claudio , Ravaud Philippe ,   European League Against Rheumatism Sjögren's Task Force
Published: March 2010

Objective

To assess and compare the sensitivity to change of the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) with that of other primary Sjögren's syndrome (SS) disease activity indexes.

Methods

We abstracted 96 patient profiles, including data on 3 successive visits (visits 1–3), from the medical charts of patients with primary SS. Patient profiles were scored with the ESSDAI, SS Disease Activity Index (SSDAI), and Sjögren's Systemic Clinical Activity Index (SCAI). Thirty‐nine experts assessed 5 profiles for whether disease activity had improved, worsened, or remained stable at visits 2 and 3.

Results

For improved patients, the standardized response means (SRMs) for all scores did not differ, and ranged from −1.08 to −1.38 between visits 1 and 2 and from −0.50 to −0.76 between visits 2 and 3. For patients with worsened activity, the SRMs between visits 1 and 2 and between visits 2 and 3 were +0.46 and +1.10 for the ESSDAI, −0.03 and +0.79 for the SSDAI, and +0.17 and +1.02 for the SCAI, respectively. For patients with stable activity, the SRMs between visits 1 and 2 and between visits 2 and 3 were 0.00 and −0.13 for the ESSDAI, −0.44 and −0.11 for the SSDAI, and −0.36 and +0.34 for the SCAI, respectively.

Conclusion

For patients with improved activity, the 3 disease activity indexes showed similar, large sensitivity to change. However, the ESSDAI seemed to detect changes in activity more accurately than other disease activity indexes. Notably, for patients with stable activity, the ESSDAI did not show erroneous improvement.
Development and initial validation of a self‐assessed lupus organ damage instrument
Authors: Costenbader Karen H. , Khamashta Munther , Ruiz‐Garcia Silvia , Perez‐Rodriguez Maria Teresa , Petri Michelle , Elliott Jennifer , Manzi Susan , Karlson Elizabeth W. , Turner‐Stokes Tabitha , Bermas Bonnie , Coblyn Jonathan , Massarotti Elena , Schur Peter , Fraser Patricia , Navarro Iris , Hanly John G. , Shaver Timothy S. , Katz Robert S. , Chakravarty Eliza , Fortin Paul R. , Sanchez Martha L. , Liu Jigna , Michaud Kaleb , Alarcón Graciela S. , Wolfe Frederick
Published: March 2010

Objective

The Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) is a validated instrument for assessing organ damage in systemic lupus erythematosus (SLE). Trained physicians must complete it, thus limiting utility where this is impossible.

Methods

We developed and pilot tested a self‐assessed organ damage instrument, the Lupus Damage Index Questionnaire (LDIQ), in 37 SLE subjects and 7 physicians. After refinement, 569 English‐speaking SLE subjects and 14 rheumatologists from 11 international SLE clinics participated in validation. Subjects and physicians completed the instruments separately. We calculated sensitivity, specificity, Spearman's correlations, and agreement using the SDI as the gold standard. Six hundred five SLE participants in the community‐based National Data Bank for Rheumatic Diseases (NDB) study completed the LDIQ and we assessed correlations with outcome and disability measures.

Results

The mean LDIQ score was 3.3 (range 0–16) and the mean SDI score was 1.5 (range 0–9). The LDIQ had a moderately high correlation with the SDI (Spearman's r = 0.50, P < 0.001). Specificities of individual LDIQ items were >80%, except for neuropathy. Sensitivities were variable and lowest for damage, with <1% prevalence. Agreement between the SDI and LDIQ was >85% for all but neuropathy, reduced renal function, deforming arthritis, and alopecia. In the NDB, the LDIQ correlated well with the comorbidity index (r = 0.45), the Short Form 36 physical component scale (r = 0.43), the Medical Research Council dyspnea scale (r = 0.40), disability (r = 0.37), and the Systemic Lupus Erythematosus Activity Questionnaire score (r = 0.37).

Conclusion

The metric properties of the LDIQ are good compared with the SDI. It has construct validity and correlations with health assessments similar to the SDI. The LDIQ should allow expansion of SLE research. Its ultimate value will be determined in longitudinal studies.
Long‐term muscular outcome and predisposing and prognostic factors in juvenile dermatomyositis: A case–control study
Authors: Sanner Helga , Kirkhus Eva , Merckoll Else , Tollisen Anita , Røisland Mona , Lie Benedicte A. , Taraldsrud Eli , Gran Jan Tore , Flatø Berit
Published: March 2010

Objective

To compare muscle strength, physical health, and HLA–DRB1 allele carriage frequencies in patients with longstanding juvenile dermatomyositis (DM) with that of controls, and to determine the presence of and risk factors for muscle weakness and magnetic resonance imaging (MRI)–detected muscle damage in juvenile DM patients.

Methods

Fifty‐nine patients with juvenile DM examined a median of 16.8 years (range 2.0–38.1 years) after disease onset were compared with 59 age‐ and sex‐matched controls. Muscle strength/endurance was measured by manual muscle testing (MMT) and the Childhood Myositis Assessment Scale (CMAS); health status was measured by the Short Form 36. HLA–DRB1 alleles were determined by sequencing in patients and 898 healthy controls. In patients, disease activity/damage was measured by the Disease Activity Score (DAS), Myositis Damage Index (MDI), Health Assessment Questionnaire/Childhood Health Assessment Questionnaire, and MRI scans of the thigh muscles. Early disease characteristics were obtained by chart review.

Results

Patients had lower muscle strength/endurance (P < 0.001 for both) and physical health (P = 0.014) and increased HLA–DRB1*0301 (P = 0.01) and DRB1*1401 (P = 0.003) compared with controls. In patients, persistent muscle weakness was found in 42% with MMT (score <78) and in 31% with the CMAS (score <48), whereas MRI‐detected muscle damage was found in 52%. Muscle weakness and MRI‐detected muscle damage were predicted by MDI muscle damage and a high DAS 1 year postdiagnosis.

Conclusion

A median of 16.8 years after disease onset, juvenile DM patients were weaker than the controls; muscle weakness/reduced endurance was found in 31–42% of patients and MRI‐detected muscular damage was found in 52% of patients. The outcomes were predicted by high disease activity and muscle damage present 1 year postdiagnosis.
Performance of rheumatoid arthritis disease activity measures and juvenile arthritis disease activity scores in polyarticular‐course juvenile idiopathic arthritis: Analysis of their ability to classify the American College of Rheumatology pediatric measures of response and the preliminary criteria for flare and inactive disease
Authors: Ringold Sarah , Bittner Rachel , Neogi Tuhina , Wallace Carol A. , Singer Nora G.
Published: March 2010

Objective

To measure the abilities of the continuous measures of disease activity used in rheumatoid arthritis (RA) and the 3 versions of the Juvenile Arthritis Disease Activity Score (JADAS; based upon 10‐, 27‐, and 71‐joint counts) to accurately classify the American College of Rheumatology (ACR) pediatric measures of response, flare, and inactive disease in polyarticular‐course juvenile idiopathic arthritis (JIA).

Methods

We conducted a secondary analysis of a randomized trial of infliximab in polyarticular‐course JIA. Disease activity was calculated at baseline and weeks 14, 28, and 52 using the Disease Activity Score (DAS), DAS in 28 joints, Simplified Disease Activity Index, Clinical Disease Activity Index, and JADAS. The ability of the RA measures and JADAS to classify each ACR pediatric measure, flare, and inactive disease was measured by areas under the receiver operating characteristic curve (AUCs). Positive predictive values (PPVs) for inactive disease were calculated.

Results

Data from 97 participants were available. The AUCs for the RA scores for each ACR pediatric measure were 0.73–0.89. The AUCs of the JADAS for the ACR pediatric measures were 0.75–0.92. The PPVs of the RA scores for inactive disease were 0.33–0.67. The PPVs of the JADAS for inactive disease were each 0.93. Based on the RA and JADAS scores, the percentage of visits misclassified as inactive disease ranged from 7–67%.

Conclusion

The RA measures and JADAS versions showed acceptable to excellent ability to classify participants for each pediatric outcome measure, but the clinical significance of differences between AUCs for these scores could not be assessed. Misclassification of active disease versus inactive disease by the RA and JADAS scores was not uncommon in this cohort.