bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free amino acids in lakes: Concentrations and assimilation rates in relation to phytoplankton and bacterial production1
Authors: Jørgensen Niels O. G. 
Published: April 2010

Diel changes of concentrations and assimilation rates of dissolved free amino acids (DFAA) were followed every third day during periods of 3–5 weeks in eutrophic Frederiksborg Slotssø and Lake Hylke and oligotrophic Lake Almind. Concentrations of DFAA varied from 78 to 3,672 nM, but most concentrations were between 200 and 1,600 nM. Diel variations of DFAA ranged from < 10%, but were occasionally 500%. In Fr. Slotssø, concentrations were maximal in the morning and minimal at noon. The high morning concentrations coincided with the diel minimum bacterial production. In Lake Hylke mean concentrations were measured at noon, but in Lake Almind no diel trends were obvious. Statistical analyses demonstrate that long‐term changes of the DFAA pools in the lakes were negatively correlated with both primary production (except Lake Almind) and bacterial production.In Fr. Slotssø and Lake Hylke, assimilation of DFAA (based on assimilation of five abundant DFAA) did not demonstrate diel trends, but within the study periods, the mean diel assimilation rates correlated negatively with primary production. In Lake Almind, no tendencies in the DFAA assimilation rates were observed. Carbon flux of DFAA assimilation in the lakes on the average made up from 6.9 to 11.3% of the primary production, and from 28.5 to 93.1% of the bacterial production, determined with the [3H]thymidine incorporation procedure. Data from the two eutrophic lakes suggest that degradation of phytoplankton can be a major source of DFAA in lakes.
Prey size selection by carnivorous stoneflies1
Authors: Allan J. David , Flecker Alexander S. , McClintock Nancy L. 
Published: April 2010

To investigate prey size preference by carnivorous stoneflies, we conducted choice experiments and directly observed predatory behavior in laboratory streams. Small, medium, and large size classes of Hesperoperla pacifica (Perlidae), small Kogotus modestus, and medium and large Megarcys signata (both of the Perlodidae) were offered an array of sizes of the mayfly Baetis as prey. Small predators displayed strong positive selection for the smallest size class of prey, and preference declined steadily with increasing prey size. Large predators displayed hump‐shaped preference curves, exhibiting strongest preference for intermediate size classes of prey. Thus size selectivity was demonstrated and varied with the size class of predator.Direct observations of encounters between predators and their prey revealed that percent attacks/ encounters by small predators was strongly biased toward small prey and by large predators was weakly biased toward large prey. Capture success always was greater and handling times shorter with small prey compared to large prey.
Nitrogen uptake and phytoplankton growth in coastal upwelling regions1
Authors: Kokkinakis Steven A. , Wheeler Patricia A. 
Published: April 2010

Uptake of nitrogenous nutrients by microplankton off the Washington and Oregon coasts was measured during the 1985 upwelling period. Nitrogen uptake rates in low‐NO3− waters (<5 µM) were 0.020–0.258 µmol N liter−1 h−1 and were primarily supported by regenerated nitrogen (71% of total uptake). Nitrogen uptake rates in high‐NO3 waters(≥20 µM) were 0.281–1.480 µmol N liter−1 h−1 and new (NO3−) nitrogen supported 83% of total uptake. Phytoplankton N was estimated by assuming a constant Chl a : PN for phytoplankton and was used to calculate phytoplankton‐specific uptake rates.Despite differences in nutrient concentrations, PN and Chl a at three upwelling sites (Oregon, Benguela, and Peru), NO3 uptake normalized to Chl a, and estimates of NO3−‐supported phytoplankton growth rates are remarkably similar. Nitrate uptake supports growth rates on the order of 1–2 d−1. Estimates of phytoplankton growth from rates of NH4+ + NO3− uptake range from 1.36 to 4.79 d−1 and are negatively correlated with concentrations of NO3− and phytoplankton N. The apparent increase in phytoplankton growth rates for waters with lower nitrogen availability may result from heterotrophic bacterial utilization of NH4+ nitrogen.
Infrared gas analysis of both gaseous and dissolved CO2 in small‐volume marine samples1
Authors: Roberts D. G. , Smith D. M. 
Published: April 2010

A simple, inexpensive infrared gas analysis system for use with small‐volume marine samples has been developed. The method involves injecting between 10 and 250 µl of a seawater sample onto an acidified gas‐stripping column. The CO2 released is transported via a nitrogen carrier gas to an infrared gas analyzer. The C.V. from seven replicate injections of a 1.0 mM Na2CO3 solution ranged from <0.3% to 1.8% depending on sample size.Evacuated blood collection tubes were used to collect and store aqueous and gaseous samples in the laboratory and field. Aqueous samples were preserved with chloroform to eliminate the possibility of changes following collection. The results indicate that samples collected in this manner can be stored for 4 weeks before analysis and that the method is efficient and cost‐effective.
The dissociation of hydrogen sulfide in seawater1
Authors: Millero Frank J. , Plese Tinka , Fernandez Marino 
Published: April 2010

The pK1* for the dissociation of H2Shas been measured in artificial seawater as a function of salinity (S = 5–40) and temperature (5°– 25°C). Results have been fitted to an equation of the form

urn:x-wiley:00243590:media:lno19883320269:lno19883320269-math-0001

where pK1 is the value at infinite dilution given by

urn:x-wiley:00243590:media:lno19883320269:lno19883320269-math-0002

(σ = 0.033 in pK*, mol kg−1 seawater). The results at S = 35 show a 0.08 shift in pK* from the results in the literature, as was also found in 0.7 m NaCl solutions. The results are in good agreement with the apparent pK1′ results when adjusted to the same pH scale. Using values for the apparent activity coefficient of the proton, we combined our results with those results to derive the consensus values of

urn:x-wiley:00243590:media:lno19883320269:lno19883320269-math-0003
In situ settling behavior of marine snow1
Authors: Alldredge Alice L. , Gotschalk Chris 
Published: April 2010

The settling velocities of undisturbed macroscopic aggregates known as marine snow were measured with SCUBA in surface waters off southern California and analyzed as a function of aggregate size, mass, and density. The mean settling velocity was 74±39 m d−1 for aggregates ranging from 2.4 to 75 mm in maximum length. Sinking rates in the field varied exponentially with aggregate size and dry weight and were consistently up to four times slower than rates measured in the laboratory.The excess densities of the 80 aggregates examined were calculated from volume and dry weight and ranged over four orders of magnitude with a median of 1.4 × 10−4 g cm−3. Aggregates of marine snow sank more slowly than predicted for either solid or porous spheres of equivalent volume and density, although their velocities were within the range expected for equivalent sinking prolate ellipsoids. No relationships between settling velocity and either excess density or particle shape were found. Drag coefficients of marine snow were also higher than predicted by theory for spheres of equivalent volume and density. These deviations from theoretical expectations may be partially explained by errors in the estimation of the excess densities of aggregates. Variability in the densities of the heterogeneous primary particles comprising marine snow (fecal pellets, clay‐mineral particles, phytoplankton, molts, etc.) and the potential for buoyancy regulation by individual phytoplankton cells inhabiting aggregates make determination of excess density especially problematic.
Fluxes and reactivities of organic matter in a coastal marine bay
Authors: Hedges John I. , Clark Wayne A. , Come Gregory L. 
Published: April 2010

Vertical fluxes of bulk particulate material, organic carbon, nitrogen, lignin‐derived phenols, and neutral sugars through the water column and into surface sediments of Dabob Bay, Washington, were determined monthly for 1 yr by sediment trap deployments at 30, 60, and 90 m at a site 110 m deep. Vertical fluxes of sinking bulk particulate material in this marine bay were elevated during winter and increased in consistent proportion to sediment trap deployment depth throughout the year. Although annual average particle fluxes at 30 and 60 m bracketed the mean accumulation rate of the underlying sediment, the flux at 90 m was higher by a factor of 2 due to resuspension, horizontal advection, or both.The monthly fluxes of lignin‐derived phenols paralleled those of total particulate material, indicating a common riverine origin. The annual average fluxes of vanillyl and cinnamyl phenols through the water column closely matched the corresponding accumulation rates in the underlying sediment, whereas about a third of the total syringyl phenol input was degraded at the water‐ sediment interface. Although p‐hydroxyacetophenone exhibited a stability typical of lignin‐derived phenols, the distinctly higher reactivities (> 60% degradation) of p‐hydroxybenzaldehyde and p‐hydroxybenzoic acid indicate a predominantly nonlignin source.On average, 60 and 70%, respectively, of the total particulate organic carbon and nitrogen and 65–75% of all neutral sugars settling through the midwater column were degraded at the water‐ sediment interface. The elemental and carbohydrate composition of the degraded material was similar to that of local net plankton except for higher percentages of glucose and total neutral sugars. Land‐derived organic material accounted for about one‐third of the total organic carbon passing through the midwater column and two‐thirds of the organic carbon accumulating in the underlying sediments. The amounts of plankton‐derived organic matter sinking through the midwater column and being preserved in the sediments below corresponded to 14 and 3% of the annual mean primary productivity. Plankton‐derived organic matter exhibited about 5 times the reactivity of local land‐derived organic matter at the water‐sediment interface of Dabob Bay and supported essentially all of the benthic respiration.
The benefits and costs of deposit feeding in the polychaete Abarenicola pacifica
Authors: Taghon Gary L. 
Published: April 2010

A mass‐balance approach was used to assess the relative importance of benefit and cost terms in a model of the energy budget of Abarenicola pacifica, a subsurface deposit‐feeding polychaete. Some model terms (sediment consumption rate, organic matter consumption rate, growth rate, standard metabolic rate) were measured directly. Other terms (absorption efficiency, mechanical cost of feeding, specific dynamic action) were obtained by simultaneous solution of model equations.Despite high rates of sediment processing (up to 280 times ash‐free dry body weight per day), the mechanical cost of deposit feeding was insignificantly low. Growth rate increased linearly over a 50‐fold range in organic matter consumption rate; this relationship was unaffected by sediment consumption rate. The model that provided the best fit to the experimental data contained a nearly constant absorption efficiency, a term for specific dynamic action (”cost of growth”) that increased linearly with intake rate of organic matter, and no mechanical cost of feeding. Models based on optimal foraging theory thus require modifications in order to describe more realistically the feeding behavior of microphagous animals.
Suppression of rotifer populations by Daphnia: A review of the evidence, the mechanisms, and the effects on zooplankton community structure1
Authors: Gilbert John J. 
Published: April 2010

There is strong evidence that rotifers cannot become abundant members of freshwater zooplankton communities in the presence of large (≳ 1.2 mm) Daphnia. Indirect evidence comes from field observations and experiments showing that rotifers are replaced by Daphnia in seasonal successions, that rotifers are much less common in communities with than without Daphnia, and that the experimental addition of zooplanktivorous fish causes the removal of Daphnia and a simultaneous increase in rotifer abundance, while the experimental removal of fish has just the opposite effect. Direct evidence comes from field experiments showing that the removal of Daphnia from communities causes a marked increase in the fertility and abundance of rotifers, and from laboratory experiments showing that Daphnia can kill and rapidly exclude rotifers in mixed‐species cultures. Rotifers are suppressed by large Daphnia both through exploitative competition for shared, limiting food resources and through mechanical interference. This interference can cause high mortality rates on susceptible rotifer species, even at low (1–5 ind. liter‒1) Daphnia densities and should affect the species structure of rotifers able to coexist with Daphnia in natural communities.Rotifers seem to be much less inhibited by small 1.2 mm) cladocerans and often co‐occur with them at high densities in natural communities in the absence of large Daphnia. There are several reasons why small cladocerans are less likely than large Daphnia to competitively suppress rotifers: small cladocerans generally do not mechanically interfere with rotifers, are less likely to deplete food resources, are themselves more likely to be suppressed by exploitative competition with rotifers, and usually are more susceptible to invertebrate predation. High rotifer abundance in the absence of Daphnia competition may have an important secondary effect in natural communities—the development of populations of invertebrate predators dependent on rotifer prey.
Estimation of downward leakage from Florida lakes1
Authors: Deevey Edward S. 
Published: April 2010

The karst lake district of peninsular Florida shares hydrologic properties with certain glaciated districts, such as outwash plains, but differs from most well‐watered regions in losing much more water to subsurface effluents than to surficial runoff. In nutrient‐loading models that begin as hydrologic throughflow models, groundwater inflow and outflow are commonly ignored or estimated from errors of closure of water budgets. Such models are inapplicable to seepage lakes, unless deep‐seepage outflow can be measured. Estimates of downward leakage from Florida lakes with and without outlets suggest that conventional nutrient‐loading models are inapplicable to any lake not in a watertigh rock basin.Downward leakage is measurable during months when lake level falls by an amount exceeding the net precipitation deficiency. To measure it, USGS stage data for 20 lakes from north, central, and south sectors of the peninsula were compared with three 32‐yr sets of mean monthly meteorologic measurements. Monthly pan‐evaporation data were converted to lake evaporation by factors estimated at Lake Okeechobee. Leakage estimates (geometric means) range from 28.4 to 50.9 cm yr‒1 in 18 of 20 lakes; two exceptionally astatic lakes gave 90.1 and 141.2 cm yr‒1 . Presence of outlets in 15 of 20 lakes makes no detectable difference in leakage. Adding evaporative losses (and ignoring surface outflow if any), residence times for the 20 lakes averaged 2.67 ± 1.33 yr.Florida lake levels fluctuate in sympathy with each other and respond with little or no lag to monthly net precipitation. Longer term swings are also evident and are more highly correlated with artesian pressure in the deep limestone aquifer than with meteorologic variables. Few if any lakes receive direct injections from this aquifer, and artesian influence is exerted on lakes and local water tables through many meters of surficial (Mio‐Pliocene) deposits.
AMDIS Case Conference
Authors: Levick D. , Schreiber R. , Graham J. 
Published: April 2010

SummaryClinical decision support that provides enhanced patient safety at the point of care frequently encounters significant pushback from clinicians who find the process intrusive or time-consuming. We present a hypothetical medical center’s dilemma about its allergy alerting system and discuss similar problems faced by real hospitals. We then share some lessons learned and best practices for institutions who wish to implement these tools themselves.
Cytology, Pathology, Frozen Section and Occult Primaries in Head and Neck Cancers
Authors: Chinoy Roshni 
Published: April 2010

Abstract
Whilst squamous cell carcinomas take center stage in the head and neck area, almost any mass disease that can occur in the rest of the body can theoretically occur here too. This includes the spectrum of adenocarcinomas, lymphomas, melanomas and sarcomas, not forgetting the diversity of salivary gland and thyroid tumors. Diagnoses by FNAC, open biopsy or frozen section have their own inherent, site specific, individualistic problems, and some of the basic principles will be highlighted. Frozen sections for resection margins and staging will be dealt with. Finally the challenge of the occult primary with metastasis in the head and neck, and understanding the need for immunohistochemistry are also touched upon.
Chemotherapy and Biologic Therapy for Squamous Cell Cancers of the Head and Neck
Authors: Mahesh Sameer 
Published: April 2010

AbstractSquamous cell carcinoma of the head and neck presents a treatment challenge owing to the complexity of the anatomy of the head and neck region. Till recently, tobacco and alcohol were thought to be the main risk factors. Recently, human papilloma virus (HPV) has gained significant attention in the etiology of oropharyngeal cancer. Depending on the location of the tumor, surgery as a primary treatment can be quite debilitating due to cosmetic as well as functional reasons. Nonsurgical (radiotherapy or chemoradiotherapy) modalities are preferred as initial treatments of oropharynx, hypopharynx and larynx primaries. A multidisciplinary approach is recommended for treatment of these malignancies.
Principles of Skull Base Reconstruction After Ablative Head and Neck Cancer Surgery
Authors: Curry Joseph , Sargi Zoukaa 
Published: April 2010

Abstract“Resection of malignancies of the skull base can result in significant functional and cosmetic morbidity as well as mortality. Reconstructive efforts provide not only functional and cosmetic rehabilitation, but also allow for the avoidance of potentially disastrous complications such as cerebrospinal fluid leak or meningitis. The optimal reconstruction is determined both by a patient based approach and a defect based approach. Skull base defects can be addressed by the separate components of the craniofacial skeleton in which they involve, and therefore the individual reconstructive issues which must be addressed. In this article, we describe an approach to skull base reconstruction and the technical aspects of the available reconstructive options.
Exercise: Adolescent Menstrual Dysfunction and Skeletal Problems
Authors: Olyai Roza , Thaker Shilpa 
Published: April 2010

ABSTRACT
Exercise is beneficial for adolescents since it increases bone mineral density (BMD) and fitness. Excessive exercise is associated with unique risk of menstrual dysfunction and skeletal problems in adolescent girls. Hypothalamic dysfunction has the key role in menstrual dysfunction and metabolic aberrations associated with nutritional insult may be the primary factor affecting low bone density in these adolescent girls. Proper physical examination and screening for eating disorder is required for the diagnosis. Treatment should be aimed at correcting metabolic abnormalities than correcting estrogen deficiency.
Standardized Visual Estimation of Blood Loss during Vaginal Delivery with its Correlation Hematocrit Changes—A Descriptive Study
Authors: Bellad MB , Laxmi BV , Goudar SS , Kumar Ashwath 
Published: April 2010

ABSTRACT

Introduction
Postpartum hemorrhage is a leading cause of maternal morbidity and mortality. Traditionally, visual method with variations in accuracy is followed, because it is quick, simple and noninvasive. To rely on this method accuracy is of vital importance. This study was aimed to improve accuracy of visual estimation of blood loss during vaginal delivery by standardizing (using similar sized mops and a fixed container) and correlating with hematocrit changes.

Methods design
A descriptive study.

Sample size
250 women. Single fixed collecting container and similar sized mops were used in the third stage of labor. Blood was drained into the container and was visually calibrated by a single trained observer. The soaking characteristics of the mops were used to estimate total blood loss. Blood spillage on delivery table, garments and floor were approximately assessed. Total blood loss was calculated from the above three sources. Hemoglobin and hematocrit measurements were done at the time of admission and, at 24 and 72 hours postpartum and its correlation was done with blood loss.

Analysis
By paired and unpaired ‘t’ test.

Results
250 out of 269 women completed the study. Incidence of PPH (> 500 ml) was 11.2%. The estimated blood loss correlated well with the hemoglobin and hematocrit changes postpartum.

Conclusion
Standardized visual method (fixed container and mops) with trained observer improves the accuracy of estimation. This may assist clinicians to accurately estimate blood loss thus preventing hemorrhage related complications.
Extreme Asynchronous Twins
Authors: Majumdar Abha , Majumdar Abha 
Published: April 2010

ABSTRACTBackgroundThis report describes a patient counseling approach, conservative and surgical management (cervical cerclage) of a dichorionic-diamniotic twin pregnancy, where delivery of the second twin followed the delivery of the first by 104 days.Case presentationA 35-year-old Indian lady, with 10 years of primary infertility, conceived twins, following ovulation induction with gonadotropin therapy. At 19 weeks and 4 days gestation, she aborted a female fetus of 410 gm. Tocolytic therapy was initiated; the placenta remainedin situand the umbilical cord of twin A was ligated high and McDonald's cerclage was placed and prophylactic antibiotics initiated. But since the patient's uterus continued to be irritable and the cerclage appeared to be under tension, at 20 weeks 6 days the stitch was taken out and all conservative treatment stopped for 24 hours, but reinitiated after this period, since the uterus remained quiescent. After 3 weeks of uterine inactivity, at 23 weeks 6 days gestation, McDonald's suture was reapplied following which conservative management was offered after counseling for possible risks associated with maternal sepsis, coagulopathy, need for extended hospitalization and potential for hysterectomy. Reassuring fetal status was observed for twin B without evidence of contractions or chorioamnionitis. A viable male infant (1800 gm) was delivered vaginally at 34 weeks and 4 days gestation.ConclusionThis report outlines a counseling approach useful for patients with premature delivery of one twin, and presents application of conservative obstetrical management principles for the aftercoming twin, even when delivery interval is extreme.
Transfection of Mouse Cochlear Explants by Electroporation
Authors: Driver Elizabeth C. , Kelley Matthew W. 
Published: April 2010

AbstractThe sensory epithelium of the mammalian inner ear, also referred to as the organ of Corti, is a remarkable structure comprised of highly ordered rows of mechanosensory hair cells and non‐sensory supporting cells located within the coiled cochlea. This unit describes an in vitro explant culture technique that can be coupled with gene transfer via electroporation to study the effects of altering gene expression during development of the organ of Corti. While the protocol is largely focused on embryonic cochlea, the same basic protocol can be used on cochleae from mice as old as P5. Curr. Protoc. Neurosci. 51:4.34.1‐4.34.10. © 2010 by John Wiley & Sons, Inc.