bluuebunny/crossref_metadata_2025 huggingface dataset:
Creutzfeldt-Jakob Disease: Focus among Libyan Jews in Israel
Authors: Kahana Esther , Alter Milton , Braham Jackson , Sofer Dov
Published: October 2006

A countrywide search for Creutzfeldt-Jakob disease in Israel disclosed 29 cases with onset between 1963 and 1972. Incidence in various ethnic groups varied in the narrow range of 0.4 to 1.9 per million population except among Jewish immigrants from Libya, among whom the incidence was 31.3 per million. An extraordinary excess of Creutzfeldt-Jakob disease exists in this ethnic group.
Carbonic Anhydrase and Osteoclasts: Localization by Labeled Inhibitor Autoradiography
Authors: Gay Carol V. , Mueller Werner J.
Published: October 2006

Autoradiography with tritiated acetazolamide indicates that osteoclasts of the hen and chick contain concentrations of carbonic anhydrase which are similar to those in pancreatic acinar cells. Grain counts of osteoblasts and osteocytes were not different from background. Thus, a sufficient quantity of carbonic anhydrase seems to be present in osteoclasts to be of physiological importance in bone resorption.
Parathyroid Hormone Effects in Rats Treated with Diphosphonate
Authors: Talmage Roy V. , Anderson J. J. B.
Published: October 2006

The ability of disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP; 40 milligrams per kilogram of body weight per day) to reduce the hypercalcemic effect of parathyroid hormone in thyroparathyroidectomized rats was confirmed. However, treatment with this large dose of EHDP enhanced the hypophosphatemic effect of a low dose of parathyroid hormone (10 international units per 100 grams of body weight), apparently by promoting the renal excretion of phosphate. The data suggest that EHDP may have a direct effect on the renal action of parathyroid hormone and, in this way, may also affect vitamin D metabolism by the kidney.
Biological Responses of
Atta texana
to Its Alarm Pheromone and the Enantiomer of the Pheromone
Authors: Riley Robert G. , Silverstein Robert M. , Moser John C.
Published: October 2006

S
-(+)-4-Methyl-3-heptanone is the principal alarm pheromone of
Atta texana
. The dextrorotatory form of the ketone has also been identified from
Atta cephalotes
. Both enantiomers have been synthesized in high optical purity;
Atta texana
is more responsive to the (+) enantiomer than to the (-) form. These results implicate a chiral receptor system.
What Happened at Hawthorne?
Authors: Parsons H. M.
Published: October 2006

The Hawthorne effect in experimental research is the unwanted effect of the experimental operations themselves. Following the Hawthorne studies, various explanations have been proposed to account for rising rates of production. Although in the Relay Assembly Test Room experiment the experimental operations may have produced other extraneous variables, a reexamination based on new and neglected evidence has yielded a new interpretation. The new variable, made more plausible because research in other contexts has shown it to have similar effects, is a combination of information feedback and financial reward. It is an example of the control of behavior by its consequences. Although several approaches may be taken to explain the effects of response-consequence contingencies, I have favored operant conditioning because it seems to account for progressive increases in response rate—the Hawthorne phenomenon. Generalizing from the particular situation at Hawthorne, I would define the Hawthorne effect as the confounding that occurs if experimenters fail to realize how the consequences of subjects' performance affect what subjects do. But the Hawthorne effect need not be viewed solely as a problem in conducting experiments. The phenomenon that created it should be studied in its own right, as Sommer suggested with a different phenomenon in mind. The study of response-consequence contingencies might well be extended to the examination of motivation in industrial workers.
Polarized Magnetic Field Fluctuations at the Apollo 15 Site: Possible Regional Influence on Lunar Induction
Authors: Schubert G. , Smith B. F. , Sonett C. P. , Colburn D. S. , Schwartz K.
Published: October 2006

High-frequency (5 to 40 millihertz) induced lunar magnetic fields, observed at the Apollo 15 site near the southeastern boundary of Mare Imbrium and the southwestern boundary of Mare Serenitatis, show a strong tendency toward linear polarization in a direction radial to the Imbrium basin and circumferential to the Serenitatis basin, a property that could be indicative of a possible regional influence on the induction.
Carbon Fixation and Isotope Discrimination by a Crassulacean Plant: Dependence on the Photoperiod
Authors: Lerman J. C. , Queiroz O.
Published: October 2006

Variations of more than 1 percent are observed in the carbon-13 to carbon-12 ratio of extracts of leaves of the succulent
Kalanchoe blossfeldiana
when the photoperiod is changed from long to short days. This indicates that the mechanism of carbon fixation switches from the Calvin (C
3
) pathway to the Hatch-Slack (C
4
) pathway of primary enzymic operation. The variations observed in the isotope compositions are tentatively explained by a model.
Search by Mariner 10 for Electrons and Protons Accelerated in Association with Venus
Authors: Simpson J. A. , Eraker J. H. , Lamport J. E. , Walpole P. H.
Published: October 2006

The University of Chicago instruments on board the Mariner 10 spacecraft bound for Mercury have measured energy spectra and fluxes of electrons from 0.18 to 30 million electron volts and protons from 0.5 to 68 million electron volts along the plasma wake and in the bow shock regions associated with Venus. Unusually quiet solar conditions and improved instrumentation made it possible to search for much lower fluxes of protons and electrons in similar energy regions as compared to earlier Mariner missions to Venus—that is, lower by a factor of 10
2
for protons and 10
3
for electrons. We found no evidence for electrons or protons either in the form of increases of intensity or energy spectral changes in the vicinity of the planet, nor any evidence of bursts of radiation in or near the observed bow shock where bursts of electrons might have been expected in analogy with the bow shock at the earth. The importance of these null results for determining the necessary and sufficient conditions for particle acceleration is discussed with respect to magnetometer evidence that Venus does not have a magnetosphere.
Barrier Island Forest Ecosystem: Role of Meteorologic Nutrient Inputs
Authors: Art Henry W. , Bormann F. Herbert , Voigt Garth K. , Woodwell George M.
Published: October 2006

The Sunken Forest, located on Fire Island, a barrier island in the Atlantic Ocean off Long Island, New York, is an ecosystem in which most of the basic cation input is in the form of salt spray. This meteorologic input is sufficient to compensate for the lack of certain nutrients in the highly weathered sandy soils. In other ecosystems these nutrients are generally supplied by weathering of soil particles. The compensatory effect of meteorologic input allows for primary production rates in the Sunken Forest similar to those of inland temperate forests.
Neonatal Thymectomy Increases the Incidence of Spontaneous and Methylcholanthrene-Enhanced Thyroiditis in Rats
Authors: Silverman David A. , Rose Noel R.
Published: October 2006

At 16 weeks of age, 13 percent of untreated Buffalo strain rats showed evidence of autoimmune thyroiditis. Feeding methylcholanthrene increased the incidence to 42 percent. Neonatal thymectomy significantly raised the incidence of disease so that almost all (87 percent) untreated and all methylcholanthrene-treated animals developed severe disease. It is proposed that the thymus exerts a regulatory effect on autosensitization.
Vagotomy: Effect on Electrically Elicited Eating and Self-Stimulation in the Lateral Hypothalamus
Authors: Ball Gordon G.
Published: October 2006

A subdiaphragmatic vagotomy markedly inhibits eating and self-stimulation produced in rats by lateral hypothalamic stimulation. The stomach is known to be affected by hypothalamic stimulation via the vagus, and afferents from the stomach can influence the hypothalamus via the same nerve. Consequently, this result suggests that eating and self-stimulation may be partly controlled by hypothalamic influences on the stomach which, in turn, affects hypothalamic sensitivity.
Cristobalitic Stage in the Diagenesis of Diatomaceous Shale
Authors: Murata K. J. , Nakata J. K.
Published: October 2006

With increasing depth of burial, diagenetic cristobalite in the Monterey Shale of California shows a decrease in the
d
(101) spacing from 4.115 to 4.040 angstroms, indicative of a progressive change in its internal structure. The spacing is 0.004 to 0.015 angstrom smaller in porcellanite than in associated chert, probably because the cristobalite of porcellanite formed later than that of chert.
Eutrophication and Recovery in Experimental Lakes: Implications for Lake Management
Authors: Schindler D. W.
Published: October 2006

Combinations of phosphorus, nitrogen, and carbon were added to several small lakes in northwestern Ontario, Canada, at rates similar to those in many culturally eutrophied lakes. Phosphate and nitrate caused rapid eutrophication. A similar result was obtained with phosphate, ammonia, and sucrose, but recovery was almost immediate when phosphate additions only were discontinued. When two basins of one lake were fertilized with equal amounts of nitrate and sucrose, and phosphorus was also added to one of the basins, the phosphate-enriched basin quickly became highly eutrophic, while the basin receiving only nitrogen and carbon remained at prefertilization conditions. These results, and the high affinity of sediments for phosphorus indicate that rapid abatement of eutrophication may be expected to follow phosphorus control measures.
Plant Species Intermediate for C
3
, C
4
Photosynthesis
Authors: Kennedy R. A. , Laetsch W. M.
Published: October 2006

Mollugo verticillata
is the first plant species reported which has characteristics of both C
3
(Calvin-Benson pathway) and C
4
(Hatch-Slack pathway) plants. This plant species is intermediate between C
3
and C
4
plants in at least four features generally used to separate those two plant groups: leaf anatomy, cell ultrastructure, photorespiration, and primary photosynthetic products.
Variation of
P
-Wave Velocity before the Bear Valley, California, Earthquake of 24 February 1972
Authors: Robinson Russell , Wesson Robert L. , Ellsworth William L.
Published: October 2006

Residuals for
P
-wave traveltimes at a seismograph station near Bear Valley, California, for small, precisely located local earthquakes at distances of 20 to 70 kilometers show a sharp increase of nearly 0.3 second about 2 months before a magnitude 5.0 earthquake that occurred within a few kilometers of the station. This indicates that velocity changes observed elsewhere premonitory to earthquakes, possibly related to dilatancy, occur along the central section of the San Andreas fault system.
Effect of Cytochrome P450 Arachidonate Metabolites on Ion Transport in Rabbit Kidney Loop of Henle
Authors: Escalante Bruno , Erlij David , Falck John R. , McGiff John C.
Published: October 2006

In the medullary segment of the thick ascending limb of the loop of Henle (mTALH), arachidonic acid (AA) is metabolized by a cytochrome P450-dependent monooxygenase to products that affect ion transport. The linkage between changes in ion transport and AA metabolism in isolated cells of the mTALH was examined. AA produced a concentration-dependent inhibition of
86
Rb uptake—an effect that was prevented by selective blockade of cytochrome P450 monooxygenases. Inhibition by cytochrome P450 blockade of the effect of AA on
86
Rb uptake could be circumvented by addition of the principal products of AA metabolism in the mTALH.
Enhanced Motility in NIH 3T3 Fibroblasts That Overexpress Gelsolin
Authors: Cunningham C. Casey , Stossel Thomas P. , Kwiatkowski David J.
Published: October 2006

Increasing the content of the actin-binding protein gelsolin in cultured mouse fibroblasts by up to 125 percent by gene transfection proportionally enhanced the rate at which the cells migrated through porous filters toward a gradient of serum and closed a wound made on a confluent monolayer of cells in a tissue culture dish. These results provide direct evidence that gelsolin, which promotes both actin assembly and disassembly in vitro, is an important element in fibroblast locomotion and demonstrate that the manipulation of intracellular machinery can increase cell motility.
Photosynthetic Mechanisms and Paleoecology from Carbon Isotope Ratios in Ancient Specimens of C
4
and CAM Plants
Authors: Troughton John H. , Wells P. V. , Mooney H. A.
Published: October 2006

Carbon isotope ratios of modern, 10,000-year-old, and more than 40,000-year-old
Atriplex confertifolia
(C
4
) material from Nevada caves indicate that the C
4
photosynthetic pathway was operating in these plants over that period. Samples of a plant with crassulacean acid metabolism,
Opuntia polyacantha
, were also measured, and a shift in the δ
13
C value from -21.9 per mil (more than 40,000 years ago) to -13.9 per mil (10,000 years ago) was observed. This provides unique physiological evidence to support the hypothesis that the late Pleistocene pluvial climate in the region already had become drier about 10,000 years ago.
Control of Membrane K
+
Permeability in a Hyperpolarizing Photoreceptor: Similar Effects of Light and Metabolic Inhibitors
Authors: Gorman A. L. F. , McReynolds John S.
Published: October 2006

In the hyperpolarizing photoreceptors of the scallop
Pecten irradians
the metabolic inhibitors cyanide and 2,4-dinitrophenol cause a rapid hyperpolarization and increase in membrane permeability to potassium ions, similar to the effect of light. Cellular metabolism appears important in maintaining the low permeability to potassium ions necessary to keep the membrane depolarized in darkness, possibly by regulating the intracellular calcium ion concentration.
Purines and Pyrimidines in Sediments from Lake Erie
Authors: van der Velden W. , Schwartz Alan W.
Published: October 2006

Quantitative analyses of purines and pyrimidines in sequential sections of cores from the central and eastern basins of Lake Erie show steeply increasing concentrations in the youngest sediments. This may be related to increased loading of nutrients and recent cultural eutrophication of the lake. The purine and pyrimidine distributions suggest the operation of a specific degradative process for uracil at an extremely early stage in, or prior to, sediment formation.
Neighbor Recognition in Two "Solitary" Carnivores: The Raccoon (
Procyon lotor
) and the Red Fox (
Vulpes fulva
)
Authors: Barash David P.
Published: October 2006

Male raccoons and red foxes were trapped alive and exposed to each other in captivity. Animals of each species trapped close to one another demonstrated a higher frequency of initial dominance-subordinance relationships and lower frequencies of more intense aggressive interactions than did animals trapped at greater distances from each other. This suggests the existence of neighbor recognition and thus a rudimentary social structure within these free-living "solitary" species.
University Isotope Separator at Oak Ridge: The UNISOR Consortium
Authors: Hamilton J. H.
Published: October 2006

The UNISOR cooperative project, envisioned more than 3 years ago, is now successfully working. Research problems that involve a full range of experiments on nuclei far from beta stability are being investigated jointly by groups of scientists from several institutions. Some of the first work reported included the identification, half-lives, and decay schemes of three new isotopes,
186
Tl,
188
Tl, and
116
I; the first or new decay schemes of
189
Tl,
190
Tl,
117
Xe, and
117
I; and the results of the perturbed gamma-gamma directional correlation work in
126
Xe.

UNISOR is already stimulating international interest. A report on the new research being planned with an isotope separator on-line to ORIC was presented at a Soviet Academy of Sciences meeting on nuclear structure in 1971. At an international nuclear physics conference in Munich in August 1973, Academician G. N. Flerov, director of the heavy-ion laboratory in Dubna, said the UNISOR project had inspired his laboratory to secure funds for a new, much improved isotope separator which is now installed on-line to their heavy-ion cyclotron to be used for detailed studies of nuclei far from stability.

The UNISOR model for research has inspired a second such project, the Atomic Physics Consortium at Oak Ridge (APCOR). After an exploratory conference at Oak Ridge, scientists from ten institutions met in November 1973 to form an organizing committee for APCOR. As with UNISOR, the universities and the AEC will each provide a significant portion of the capital and operating costs. Heavy ions have opened up much new research in atomic physics, but such accelerator-based research represents a real "shift from traditional approaches concerning how, where, and on what time scale atomic physics experiments should be done".
Menstrual Cycles: Fatness as a Determinant of Minimum Weight for Height Necessary for Their Maintenance or Onset
Authors: Frisch Rose E. , McArthur Janet W.
Published: October 2006

Weight loss causes loss of menstrual function (amenorrhea) and weight gain restores menstrual cycles. A minimal weight for height necessary for the onset of or the restoration of menstrual cycles in cases of primary or secondary amenorrhea due to undernutrition is indicated by an index of fatness of normal girls at menarche and at age 18 years, respectively. Amenorrheic patients of ages 16 years and over resume menstrual cycles after weight gain at a heavier weight for a particular height than is found at menarche. Girls become relatively and absolutely fatter from menarche to age 18 years. The data suggest that a minimum level of stored, easily mobilized energy is necessary for ovulation and menstrual cycles in the human female.
Paradoxical Effects after Microinjection of Morphine in the Periaqueductal Gray Matter in the Rat
Authors: Jacquet Yasuko F. , Lajtha Abel
Published: October 2006

Paradoxical, concurrent hyper- and hyporeactivity of a profound nature to specific stimuli occurred when 10 micrograms of morphine was microinjected bilaterally into the periaqueductal gray matter of the rat brain. Both effects at this site were dose-dependent. The hyperreactivity (to previously neutral auditory and visual stimuli) was obtained only with intracerebrally injected morphine and never with intraperitoneally injected morphine or with other opiates administered either way. Rapid tolerance to toxic doses of morphine developed at this site, as well as cross tolerance of the hyporeactivity to painful stimuli between routes (intracerebral to intraperitoneal) of morphine administration. Both the hyper- and hyporeactivity were fully reversible by intracerebral injection of naloxone in the periaqueductal gray. Thus, the periaqueductal gray appears to be a major pathway for morphine action.
Genetic Recombination in the Dinoflagellate
Crypthecodinium cohnii
Authors: Tuttle R. C. , Loeblich A. R.
Published: October 2006

Genetic recombination in dinoflagellates has been detected with the use of chemically induced carotene-deficient mutants of
Crypthecodinium cohnii
.
Judgment under Uncertainty: Heuristics and Biases
Authors: Tversky Amos , Kahneman Daniel
Published: October 2006

This article described three heuristics that are employed in making judgments under uncertainty: (i) representativeness, which is usually employed when people are asked to judge the probability that an object or event A belongs to class or process B; (ii) availability of instances or scenarios, which is often employed when people are asked to assess the frequency of a class or the plausibility of a particular development; and (iii) adjustment from an anchor, which is usually employed in numerical prediction when a relevant value is available. These heuristics are highly economical and usually effective, but they lead to systematic and predictable errors. A better understanding of these heuristics and of the biases to which they lead could improve judgments and decisions in situations of uncertainty.
A Calcium-Dependent Protein Kinase with a Regulatory Domain Similar to Calmodulin
Authors: Harper Jeffrey F. , Sussman Michael R. , Schaller G. Eric , Putnam-Evans Cindy , Charbonneau Harry , Harmon Alice C.
Published: October 2006

Calcium can function as a second messenger through stimulation of calcium-dependent protein kinases. A protein kinase that requires calcium but not calmodulin or phospholipids for activity has been purified from soybean. The kinase itself binds calcium with high affinity. A complementary DNA clone for this kinase has been identified; it encodes a protein with a predicted molecular mass of 57,175 daltons. This protein contains a catalytic domain similar to that of calmodulin-dependent kinases and a calmodulin-like region with four calcium binding domains (EF hands). The predicted structure of this kinase explains its direct regulation via calcium binding and establishes it as a prototype for a new family of calcium-regulated protein kinases.
Cloning of a Factor Required for Activity of the Ah (Dioxin) Receptor
Authors: Hoffman Emily C. , Reyes Herminio , Chu Fong-Fong , Sander Fred , Conley Linda H. , Brooks Barbara A. , Hankinson Oliver
Published: October 2006

The aryl hydrocarbon (Ah) receptor binds various environmental pollutants, such as polycyclic aromatic hydrocarbons, heterocyclic amines, and polychlorinated aromatic compounds (dioxins, dibenzofurans, and biphenyls), and mediates the carcinogenic effects of these agents. The complementary DNA and part of the gene for an 87-kilodalton human protein that is necessary for Ah receptor function have been cloned. The protein is not the ligand-binding subunit of the receptor but is a factor that is required for the ligand-binding subunit to translocate from the cytosol to the nucleus after binding ligand. The requirement for this factor distinguishes the Ah receptor from the glucocorticoid receptor, to which the Ah receptor has been presumed to be similar. Two portions of the 87-kilodalton protein share sequence similarities with two
Drosophila
proteins, Per and Sim. Another segment of the protein shows conformity to the consensus sequence for the basic helix-loop-helix motif found in proteins that bind DNA as homodimers or heterodimers.
MHC Class I Deficiency: Susceptibility to Natural Killer (NK) Cells and Impaired NK Activity
Authors: Liao Nan-Shih , Bix Mark , Zijlstra Maarten , Jaenisch Rudolf , Raulet David
Published: October 2006

The role of major histocompatibility complex (MHC) class I expression in natural killer (NK) cell target recognition is controversial. Normal T cell blasts from MHC class I-deficient mutant mice were found to serve as target cells for NK cells in vitro, which suggests that MHC class I molecules are directly involved in NK cell recognition. Spleen cells from the mutant mice were deficient in their ability to lyse MHC class I-deficient target cells or NK-susceptible tumor targets, and mutant mice could not reject allogeneic bone marrow. Thus, class I molecules may participate in the positive selection or tolerance induction of NK cells.
Identification of Profilin as a Novel Pollen Allergen; IgE Autoreactivity in Sensitized Individuals
Authors: Valenta Rudolf , Duchêne Michael , Pettenburger Karin , Sillaber Christian , Valent Peter , Bettelheim Peter , Breitenbach Michael , Rumpold Helmut , Kraft Dietrich , Scheiner Otto
Published: October 2006

A complementary DNA encoding a pollen allergen from white birch (
Betula verrucosa
) that was isolated from a pollen complementary DNA library with serum immunoglobulin E from a birch pollen-allergic individual revealed significant sequence homology to profilins. The recombinant protein showed high affinity to poly-L-proline. Immunoglobulin E antibodies from allergic individuals bound to natural and recombinant birch profilin and also to human profilin. In addition, birch and human profilin induced histamine release from blood basophils of profilin-allergic individuals, but not of individuals sensitized to other plant allergens. The structural similarity of conserved proteins might therefore be responsible for maintaining immunoglobulin E antibody titers in type I allergy.
Variations of Rayleigh Wave Phase Velocities across the Pacific Ocean
Authors: Kausel Edgar G. , Leeds Alan R. , Knopoff Leon
Published: October 2006

Rayleigh wave phase velocities on paths crossing the Pacific Ocean show variations which are well correlated with some "average" lithospheric age of the region traversed. The seismic velocities in the upper mantle are highest in the oldest parts of the Pacific and lowest in the youngest parts.
Alkanes at the Air-Sea Interface from Offshore Louisiana and Florida
Authors: Ledet Enoch J. , Laseter John L.
Published: October 2006

Alkanes at the air-sea interface were analyzed in 118 surface samples collected at five different intervals over a 12-month period from Timbalier Bay (Louisiana), offshore Louisiana, and offshore Florida. The alkanes were characterized by gas chromatography and mass spectrometry. Unexpectedly, methyl branched alkanes ranging in chain length from C
15
to C
35
and cycloalkanes were frequently the predominant components. This suggests that the alkanes are produced by natural biological sources as well as human activities.
Water Salination: A Source of Energy
Authors: Norman Richard S.
Published: October 2006

The thermodynamically reversible mixing of freshwater and seawater at constant temperature releases free energy. Salination power as a resource is comparable with hydroelectric power in magnitude; U.S. freshwater runoff could yield over 10
10
watts. The energy flux available for natural salination is equivalent to each river in the world ending at its mouth in a waterfall 225 meters high. An osmotic salination converter could possibly operate at 25 percent efficiency. This energy source is renewable and nonpolluting. Although its full utilization would destroy estuarine environments, it might be practical for specialized purposes.
Urban Aerosol Toxicity: The Influence of Particle Size
Authors: Natusch David F. S. , Wallace John R.
Published: October 2006

The basic thesis developed herein is that particle size is an extremely important parameter to consider when assessing the potential toxicity of species present in urban aerosols, and that surface adsorption or condensation greatly promotes toxicity. In the majority of cases this means that particles that are less than 1 μm in size are of primary importance. Special significance is attached to the organic constitutents of aerosols. Many of these are known or potential carcinogens and most predominate in extremely small particles which become deposited almost exclusively in the lung.
Negative Resistance Characteristic Essential for the Maintenance of Slow Oscillations in Bursting Neurons
Authors: Wilson Wilkie A. , Wachtel Howard
Published: October 2006

Voltage clamping giving step commands reveals a steady-state negative resistance characteristic in the current-voltage curves of
Aplysia
bursting neurons. This is observed below spike threshold in the unstable range through which the membrane potential slowly oscillates. The negative resistance characteristic underlies this instability and shapes the rapid depolarization-hyperpolarization phase of the cycle. When bursting cells are converted to silent cells (by cooling) the negative resistance is abolished; conversely, when normally silent cells are made to burst (by warming) a negative resistance develops. The presence of negative resistance thus enables the bursting cell to oscillate, whereas its absence precludes such oscillations.
Lead Contamination around Secondary Smelters: Estimation of Dispersal and Accumulation by Humans
Authors: Roberts T. M. , Hutchinson T. C. , Paciga J. , Chattopadhyay A. , Jervis R. E. , Vanloon J. , Parkinson D. K.
Published: October 2006

A high rate of lead fallout around two secondary lead smelters originated mainly from episodal large-particulate emissions from low-level fugitive sources rather than from stack fumes. The lead content of dustfall, and consequently of soil, vegetation, and outdoor dust, decreased exponentially with distance from the two smelters. Between 13 and 30 percent of the children living in the contaminated areas had absorbed excessive amounts of lead (more than 40 micrograms per 100 milliliters of blood and more than 100 micrograms per gram of hair) as compared with less than 1 percent in a control group. A relationship between blood and hair was established which indicated that the absorption was fairly constant for most children examined. It seemed that the ingestion of contaminated dirt and dusts rather than "paint pica" was the major route of lead intake. Metabolic changes were found in most of 21 children selected from those with excessive lead absorption; 10 to 15 percent of this group showed subtle neurological dysfunctions and minor psychomotor abnormalities.
Steroid 5α-Reductase Deficiency in Man: An Inherited Form of Male Pseudohermaphroditism
Authors: Imperato-McGinley Julianne , Guerrero Luis , Gautier Teofilo , Peterson Ralph E.
Published: October 2006

In male pseudohermaphrodites born with ambiguity of the external genitalia but with marked virilization at puberty, biochemical evaluation reveals a marked decrease in plasma dihydrotestosterone secondary to a decrease in steroid 5 α-reductase activity. In utero the decrease in dihydrotestosterone results in incomplete masculinization of the external genitalia. Inheritance is autosomal recessive.
Crystal Structure of the Catalytic Subunit of Cyclic Adenosine Monophosphate-Dependent Protein Kinase
Authors: Knighton Daniel R. , Zheng Jianhua , Ten Eyck Lynn F. , Ashford Victor A. , Xuong Nguyen-Huu , Taylor Susan S. , Sowadski Janusz M.
Published: October 2006

The crystal structure of the catalytic subunit of cyclic adenosine monophosphate-dependent protein kinase complexed with a 20-amino acid substrate analog inhibitor has been solved and partially refined at 2.7 Å resolution to an
R
factor of 0.212. The magnesium adenosine triphosphate (MgATP) binding site was located by difference Fourier synthesis. The enzyme structure is bilobal with a deep cleft between the lobes. The cleft is filled by MgATP and a portion of the inhibitor peptide. The smaller lobe, consisting mostly of amino-terminal sequence, is associated with nucleotide binding, and its largely antiparallel β sheet architecture constitutes an unusual nucleotide binding motif. The larger lobe is dominated by helical structure with a single β sheet at the domain interface. This lobe is primarily involved in peptide binding and catalysis. Residues 40 through 280 constitute a conserved catalytic core that is shared by more than 100 protein kinases. Most of the invariant amino acids in this conserved catalytic core are clustered at the sites of nucleotide binding and catalysis.
Synaptic Facilitation and Behavioral Sensitization in
Aplysia
: Possible Role of Serotonin and Cyclic AMP
Authors: Brunelli M. , Castellucci V. , Kandel E. R.
Published: October 2006

The neural changes accompanying sensitization of the gill-withdrawal reflex in
Aplysia
are associated with presynaptic facilitation at monosynaptic connections between sensory neurons and motor cells. To analyze the molecular mechanisms underlying the facilitation, the pharmacological actions of serotonin, octopamine, and dopamine were examined. Only serotonin enhanced synaptic transmission between the sensory and the motor neurons. A serotonin antagonist, cinanserin, reversibly blocked the synaptic facilitation. The action of serotonin may be mediated by adenosine 3′,5′-monophosphate (cyclic AMP). Exposing the ganglion to dibutyryl cyclic AMP or injecting cyclic AMP into the cell body enhances the synaptic action of a sensory neuron. The mechanism of presynaptic facilitation, therefore, may include activation of one or more serotonergic neurons, which enhance the release of a neurotransmitter by increasing the intracellular concentration of cyclic AMP in the terminals of the sensory neurons.
Petroleum Pollutants in Surface and Groundwater as Indicated by the Carbon-14 Activity of Dissolved Organic Carbon
Authors: Spiker E. C. , Rubin Meyer
Published: October 2006

The
14
C activity of dissolved organic carbon (DOC) can be used to distinguish between the fossil organic carbon due to petrochemical effluents and modern organic carbon due to domestic wastes and natural decaying organic matter. Rivers polluted by petrochemical effluents show varying amounts of depression of the DOC
14
C activity, reflecting concentrations of
14
C-deficient fossil carbon of as much as about 40 percent of the total DOC.
Fossils of Uncertain Affinity from the Upper Devonian of Iowa
Authors: Davis Richard Arnold , Semken Holmes A.
Published: October 2006

Thousands of specimens of the enigmatic fossil
Gluteus minimus
(new genus, new species) occur in a 5-centimeter-thick interval within the Maple Mill Shale and in equivalent deposits of the Devonian of eastern Iowa. They are roughly lenticular. bilobed fossils up to 11 millimeters in diameter and 8 millimeters thick. These objects consistently asymmetrical in the same direction. defy placement in any known higher taxon when their morphology. histology, and apatitic composition are considered.
Drought in the Sahara: A Biogeophysical Feedback Mechanism
Authors: Charney Jule , Stone Peter H. , Quirk William J.
Published: October 2006

Two integrations of a global general circulation model, differing only in the prescribed surface albedo in the Sahara, show that an increase in albedo resulting from a decrease in plant cover causes a decrease in rainfall. Thus any tendency for plant cover to decrease would be reinforced by a decrease in rainfall, and could initiate or perpetuate a drought.
Optical Levitation of Liquid Drops by Radiation Pressure
Authors: Ashkin A. , Dziedzic J. M.
Published: October 2006

Charged and neutral liquid drops in the diameter range from 1 to 40 microns can be stably levitated and manipulated with laser beams. The levitation technique has been extended toward smaller particles (about 1 micron), lower laser power (less than 1 milliwatt), and deeper traps (greater than ten times the particle's weight). The techniques developed here have particular importance in cloud physics, aerosol science, fluid dynamics, and optics. The interactions of the drops with light, the electric field, the surrounding gas, and one another can be observed with high precision.
Human Skeletal Muscle: Properties of the "Chemically Skinned" Fiber
Authors: Wood Donald S. , Zollman Jenny , Reuben John P. , Brandt Philip W.
Published: October 2006

A "skinning" procedure is described for irreversibly disrupting the sarcolemmal membrane of human skeletal muscle and allowing calcium and other diffusible solutes (such as adenosine triphosphate) access to the myofilament space. Single skinned fibers give isometric tensions of about 1.5 kilograms per square centimeter when exposed to ionized calcium even after 1 to 2 weeks of storage at 5°C. For up to 5 days the preparation will sequester and, under appropriate conditions (anion substitution, caffeine addition, or magnesium withdrawal), release calcium. The regulation of intracellular calcium distribution and the calcium-induced activation of the contractile proteins are discussed and related to the morphology of human fibers and to similar processes occurring in other muscle preparations.
A Novel, Highly Stable Fold of the Immunoglobulin Binding Domain of Streptococcal Protein G
Authors: Gronenborn Angela M. , Filpula David R. , Essig Nina Z. , Achari Aniruddha , Whitlow Marc , Wingfield Paul T. , Clore G. Marius
Published: October 2006

The high-resolution three-dimensional structure of a single immunoglobulin binding domain (B1, which comprises 56 residues including the NH
2
-terminal Met) of protein G from group G
Streptococcus
has been determined in solution by nuclear magnetic resonance spectroscopy on the basis of 1058 experimental restraints. The average atomic root-mean-square distribution about the mean coordinate positions is 0.27 angstrom (Å) for the backbone atoms, 0.65 Å for all atoms, and 0.39 Å for atoms excluding disordered surface side chains. The structure has no disulfide bridges and is composed of a four-stranded β sheet, on top of which lies a long helix. The central two strands (β1 and β4), comprising the NH2- and COOH-termini, are parallel, and the outer two strands (β2 and β3) are connected by the helix in a +3
x
crossover. This novel topology (-1, +3
x
, -1), coupled with an extensive hydrogen-bonding network and a tightly packed and buried hydrophobic core, is probably responsible for the extreme thermal stability of this small domain (reversible melting at 87°C).
Quantitative Formulation of Reliability in Stratigraphic Correlation
Authors: Southam John R. , Hay William W. , Worsley Thomas R.
Published: October 2006

The probability that two stratigraphic events are in a particular order in a section in which they occur in sequence is p. Because of finite sampling, statistical techniques are used to calculate the parameters
p
′ and
p
l
, which express the uncertainty of our knowledge of p;
p̂
′ is the measured value of the maximum likelihood estimator of
p
and
p
l
is the lower end point of the confidence interval on which
p
must lie. The most reliable sequence for stratigraphic correlation is obtained by maximizing the parameter
p̂
′/ (1-
p
l
) between pairs of events.
Wright's Shifting Balance Theory: An Experimental Study
Authors: Wade Michael J. , Goodnight Charles J.
Published: October 2006

Experimental confirmation of Wright's shifting balance theory of evolution, one of the most comprehensive theories of adaptive evolution, is presented. The theory is regarded by many as a cornerstone of modern evolutionary thought, but there has been little direct empirical evidence supporting it. Some of its underlying assumptions are viewed as contradictory, and the existence and efficacy of the theory's fundamental adaptive process, interdemic selection, is the focus of controversy. Interdemic selection was imposed on large arrays of laboratory populations of the flour beetle Tribolium castaneum in the manner described by Wright: the differential dispersion of individuals from demes of high fitness into demes of low fitness. A significant increase in average fitness was observed in the experimental arrays when compared to control populations with equivalent but random migration rates. The response was not proportional to the selection differential: The largest response occurred with interdemic selection every two generations rather than every generation or every three generations. The results indicate that the interdemic phase of Wright's shifting balance theory can increase average fitness and suggest that gene interactions are involved in the observed response.
Animal Choice Behavior and the Evolution of Cognitive Architecture
Authors: Real Leslie A.
Published: October 2006

Animals process sensory information according to specific computational rules and, subsequently, form representations of their environments that form the basis for decisions and choices. The specific computational rules used by organisms will often be evolutionarily adaptive by generating higher probabilities of survival, reproduction, and resource acquisition. Experiments with enclosed colonies of bumblebees constrained to foraging on artificial flowers suggest that the bumblebee's cognitive architecture is designed to efficiently exploit floral resources from spatially structured environments given limits on memory and the neuronal processing of information. A non-linear relationship between the biomechanics of nectar extraction and rates of net energetic gain by individual bees may account for sensitivities to both the arithmetic mean and variance in reward distributions in flowers. Heuristic rules that lead to efficient resource exploitation may also lead to subjective misperception of likelihoods. Subjective probability formation may then be viewed as a problem in pattern recognition subject to specific sampling schemes and memory constraints.
Climatic Change: Are We on the Brink of a Pronounced Global Warming?
Authors: Broecker Wallace S.
Published: October 2006

If man-made dust is unimportant as a major cause of climatic change, then a strong case can be made that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide. By analogy with similar events in the past, the natural climatic cooling which, since 1940, has more than compensated for the carbon dioxide effect, will soon bottom out. Once this happens, the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years.
Jupiter: Its Infrared Spectrum from 16 to 40 Micrometers
Authors: Houck James R. , Pollack James B. , Schaack David , Reed Robert A. , Summers A.
Published: October 2006

Spectral measurements of the thermal radiation from Jupiter in the band from 16 to 40 micrometers are analyzed under the assumption that pressure-broadened molecular hydrogen transitions are responsible for the bulk of the infrared opacity over most of this spectral interval. Both the vertical pressure-temperature profile and the molecular hydrogen mixing ratio are determined. The derived value of the molecular hydrogen mixing ratio, 0.89 ± 0.11, is consistent with the solar value of 0.86.
Preventive Medicine: Legislation Calls for Health Education
Authors: Culliton Barbara J.
Published: October 2006

It appears that therapeutic medicine, important as it is, may have reached a point of diminishing returns. The 12 to 15 percent increases that we are adding to our hundred billion dollar health care bill each year—even the portion that is not caused by inflation—apparently have only a marginal utility.
A68: a Major Subunit of Paired Helical Filaments and Derivatized Forms of Normal Tau
Authors: Lee Virginia M.-Y. , Balin Brian J. , Otvos Laszlo , Trojanowski John Q.
Published: October 2006

Putative Alzheimer disease (AD)-specific proteins (A68) were purified to homogeneity and shown to be major subunits of one form of paired helical filaments (PHFs). The amino acid sequence and immunological data indicate that the backbone of A68 is indistinguishable from that of the protein tau (τ), but A68 could be distinguished from normal human τ by the degree to which A68 was phosphorylated and by the specific residues in A68 that served as phosphate acceptors. The larger apparent relative molecular mass (
M
r
) of A68, compared to normal human τ, was attributed to abnormal phosphorylation of A68 because enzymatic dephosphorylation of A68 reduced its
M
r
to close to that of normal τ. Moreover, the LysSerProVal motif in normal human τ appeared to be an abnormal phosphorylation site in A68 because the Ser in this motif was a phosphate acceptor site in A68, but not in normal human τ. Thus, the major subunits of a class of PHFs are A68 proteins and the excessive or inappropriate phosphorylation of normal τ may change its apparent
M
r
, thus transforming τ into A68.
Predicting and Observing El Niño
Authors: Wyrtki Klaus , Stroup Edward , Patzert William , Williams Robert , Quinn William
Published: October 2006

In October 1974 the occurrence of a weak El Niño event was predicted for early 1975 on the basis of the southern oscillation index. An expedition was organized to observe the event in the waters off Peru and Ecuador during two cruises in order to study its occurrence and its development with time. During the first cruise a massive transgression of warm low salinity water across the equator to 4°S was observed, as well as a depression of the thermocline along the equator and off the coast of South America, indicating the start of El Niño development. During the second cruise the oceanographic situation had changed and conditions were returning to normal.
Hydration Rate of Obsidian
Authors: Friedman Irving , Long William
Published: October 2006

The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95° to 245°C. An expression relating hydration rate to temperature was derived for each sample. The SiO
2
content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents.

With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates.

If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to ± 10 percent of the true age over periods as short as several years and as long as millions of years.
Mineral Inclusions in Diamond: Temperature and Pressure of Equilibration
Authors: Meyer Henry O. A. , Tsai Hsiao-Ming
Published: October 2006

Two distinct suites of minerals included in natural diamond occur and probably represent different physical and chemical conditions during diamond growth. Minerals of the ultramafic suite appear to have equilibrated in the range 1000° to 1300°C between 45 and 65 kilobars, whereas the temperature range for minerals of the eclogitic suite is 850° to 1250°C. At present, models relating the partitioning of magnesium and iron between coexisting phases are not sufficiently rigorous to determine a value for the pressure of equilibration of these eclogitic suite inclusions.
Reproductive and Vegetative Morphology of a Cretaceous Angiosperm
Authors: Dilcher David L. , Crepet William L. , Beeker Charles D. , Reynolds Howard C.
Published: October 2006

Recent collections from plant-bearing deposits of Cenomanian age in central Kansas have yielded angiosperm axes with helically arranged, seed-bearing, conduplicate carpels. Large leaves associated with these fruits are thought to represent parts of the same kind of plant because the leaves and fruits are the only plant fossils at this locality to have distinctive, morphologically identical, yellow bodies within their carbonaceous remains. These fossils provide a rare opportunity to study the morphology of an ancient angiosperm and illustrate the antiquity of certain features considered primitive by comparative angiosperm morphologists.
Stratospheric Ozone Effects on Temperature
Authors: Reck Ruth A.
Published: October 2006

Calculated surface temperature changes, ΔT
8
, due to stratospheric ozone depletion (at 35°N latitude in April) are less than previously estimated and range between –0.6 and +0.9°K. The sign of ΔT
8
is determined by the surface albedo and the presence or absence of a low-lying particulate layer (heating with particles, cooling without particles). The calculations indicate that a 90 percent stratospheric ozone depletion does not cause the temperature inversion at the tropopause to vanish, although it is weakened substantially.
Electrical Energy Storage and Intercalation Chemistry
Authors: Whittingham M. S.
Published: October 2006

The electrochemical reaction of layered titanium disulfide with lithium giving the intercalation compound lithium titanium disulfide is the basis of a new battery system. This reaction occurs very rapidly and in a highly reversible manner at ambient temperatures as a result of structural retention. Titanium disulfide is one of a new generation of solid cathode materials.