bluuebunny/crossref_metadata_2025 huggingface dataset:
Adjacency constraints in harvest scheduling: an aggregation heuristic
Authors: Torres-Rojo Juan M. , Brodie J. Douglas
Published: May 2008

An heuristic for adjacency constraint aggregation is proposed. The heuristic is composed of two procedures. Procedure 1 consists of identifying harvesting areas for which it is not necessary to write adjacency constraints. Procedure 2 consists of writing one adjacency constraint for each one of the harvesting areas not identified in procedure 1. Such adjacency constraints consider all the adjacency relations between the harvesting area and its surrounding areas. The heuristic is based on the concept of penalties and the four-color theorem. The aggregated constraints present fewer variables per constraint than the aggregator described by B.J. Meneghin, M.W. Kirby, and J.G. Jones (1988. USDA For. Serv. Rocky Mt. For. Range Exp. Stn. Gen. Tech. Rep. RM-161. pp. 46–53) and can easily be generated mechanically from the adjacency matrix. In addition, the proposed heuristic does not require the tedious task of identifying type 1 and 2 constraints as with Meneghin's algorithm. Hence the combinatorial work to compute the aggregated constraints is reduced significantly. Comparisons showed that the proposed heuristic requires about a third of the constraints required by the conventional adjacency constraint formulation and about the same number of constraints as the procedure suggested by B.J. Meneghin, M.W. Kirby, and J.G. Jones (1988).
The probability of root disease on the Lolo National Forest, Montana
Authors: Byler James W. , Marsden Michael A. , Hagle Susan K.
Published: May 2008

Root disease killed trees in 33% of 579 stands on the Lolo National Forest, Montana. Of all the commercial forest land, 123 255 ha, or 18.8%, was diseased; 1.2% was in nonstocked patches. The statistical method CART (classification and regression trees) was used to construct a decision tree to place stands into one of four classes, based on the probability that the stands contained trees that were killed by root disease. High probabilities of root disease were found for stands in the western hemlock and grand fir habitat type series (0.59) and in other habitat types on moderate slopes with southerly aspects (0.48). Low probabilities of disease were found on non-hemlock and non grand fir types on northerly aspects (0.15) and southerly aspects that were on either flat or very rugged terrain (0.17). Both Phellinusweirii (Murr.) Gilb. and Armillaria sp., probably A. ostoyae (Romagna) Herick, were frequently associated with mortality in hemlock, grand fir, and cedar habitat type series. Only A. ostoyae was common on Douglas-fir and subalpine fir habitat type series, however. Selective harvest and fire control in these two classes may contribute to the extensive root disease mortality found in Lolo National Forest at present.
Photosynthesis, water relations, and foliar nitrogen of Piceamariana and Larixlaricina from drained and undrained peatlands
Authors: Macdonald S. Ellen , Lieffers Victor J.
Published: May 2008

Rates of net assimilation and related ecophysiological parameters were measured three times during the 1988 growing season on a total of 80 black spruce (Piceamariana (Mill.) B.S.P.) and 80 tamarack (Larixlaricina (Du Roi) K. Koch) trees from two peatland locations, each with paired drained and undrained plots. Ditching for drainage was completed in March 1984. There was no evidence of improved water relations in trees on the drained plots. The initial effect of drainage was the improvement of nitrogen relations. This, in turn, was associated with higher rates of net assimilation. In general, trees in the drained plots were characterized by higher rates of net assimilation, water-use efficiency, mesophyll conductance to CO2, a lower ratio of intercellular to ambient partial pressure of CO2, and higher foliar nitrogen content. For tamarack, the drainage effect was only significant at one location, which was described as the poorer site. For both species, measures of net assimilation and foliar nitrogen were positively correlated with leader growth.
Errors in the calculation of evaporation and leaf conductance in steady-state porometry: the importance of accurate measurement of leaf temperature
Authors: Tyree M. T. , Wilmot T. R.
Published: May 2008

Leaf temperatures of sugar maple leaves (Acersaccharum Marsh.) were measured over three growth seasons using in situ copper–constantan thermocouples with wire and junction diameters of 70 and 130 μm, respectively. These thermocouples were coated with a thin layer of adhesive and attached to the abaxial leaf surface over a length of 4 to 5 cm of wire. On sunny days leaf temperatures usually rose 5 to 15 °C above the air temperature. When leaf conductances and evaporative flux were measured with a Li-Cor steady-state porometer under the same conditions, similar leaf temperatures were rarely measured by the Li-Cor leaf thermocouple. We argue that the in situ thermocouple is more likely to measure the actual leaf temperature than the Li-Cor thermocouple. Consequently, the values for leaf conductance and evaporative flux computed by the Li-Cor microprocessor can be wrong by as much as a factor of 2. Errors of similar magnitude may apply to other published measurements for forest species but are not as large in many crop species.
Browse selection by beaver: effects on riparian forest composition
Authors: Johnston Carol A. , Naiman Robert J.
Published: May 2008

Beaver (Castorcanadensis) herbivory has both immediate and long-term effects on biomass, structure, and composition of riparian forests. Intense beaver foraging of trembling aspen (Populustremuloides Michx.) decreased tree density and basal area by as much as 43% within ~ 1-ha forage zones surrounding two beaver ponds in northern Minnesota. Maximum diameter of trees cut was 43.5 cm; average aspen stem diameter cut was 13.9 and 10.2 cm at the two ponds. Woody biomass harvested per beaver averaged 1.4 Mg•ha−1•year−1 over a 6-year foraging period. Most wood harvested was left on site or used in dam construction, rather than consumed. Selective foraging by beaver decreased the relative importance of preferred species (i.e., P. tremuloides) and increased the importance of avoided species (i.e., Alnusrugosa (Du Roi) Spreng., Piceaglauca (Moench) Voss), with long-term implications to forest succession and dynamics.
Ratio of fixed and assimilated nitrogen in a black alder (Alnusglutinosa) stand
Authors: Beaupied Henri , Moiroud André , Domenach Anne-Marie , Kurdali Fawaz , Lensi Robert
Published: May 2008

The ratio of fixed and assimilated nitrogen was determined in a black alder (Alnusglutinosa (L.) Gaertn.) stand throughout a growing season by measuring symbiotic dinitrogen fixation, soil mineral nitrogen concentration, and soil nitrifying capacity. The symbiotic dinitrogen fixation evaluated by the method based on natural isotopic abundance, δ15N) showed that most nitrogen present in alder leaves was derived from fixation (94%). Nitrogenase activity, measured by acetylene reduction assay, began at bud break and continued over the growing season, but showed great variation. The upper soil layer (0–15 cm) beneath black alder contained ammonium and nitrate nitrogen on sampling dates. Nitrification, determined by biological nitrous oxide (N2O) production after a short insitu incubation, occurred throughout the season. Black alders satisfied most of their nitrogen requirements from an atmospheric origin.
Réponses de souches de bouleau à la mycorhization et au sel
Authors: Catinus B. , Guerrier G. , Strullu D. G.
Published: May 2008

Two selected birch (Betulapendula) clones, isolated invitro, were studied for their responses to salt and mycorrhization. After 60 days of culture, when inoculated with Paxillusinvolutus, clone 4 showed the most growth stimulation, 120%, against 55% for clone 5. Clone 4 is also more tolerant to NaCl than clone 5, their respective decreases in biomass being 10 and 40% in medium containing 50 mM NaCl. Salt and mycorrhizal responses were linked to the osmotic and nutritional status of vitroplants. Translocation of ions towards the shoots thus appears to be involved in these cross-tolerances.
Effects of nitrogen fertilization on the fluxes of N2O, CH4, and CO2 from soils in a Florida slash pine plantation
Authors: Castro Mark S. , Peterjohn William T. , Melillo Jerry M. , Steudler Paul A. , Gholz Henry L. , Lewis David
Published: May 2008

We measured fluxes of N2O, CH4 and CO2 from control and urea-nitrogen fertilized soils of a mature slash pine (Pinuselliottii var. elliottii Englem.) plantation in Alachua County, Florida. The fertilization did not affect CO2 emissions, but significantly increased the emissions of N2O and lowered the uptake of atmospheric CH4. Daily average N2O emissions from the fertilized soils were 8–600 times higher (12–74 μg N2O-N•m−2•h−1) than daily average N2O emissions from control soils (0.02–4.0 μg N2O-N•m−2•h−1). Daily average CH4 uptake by the fertilized soils were 5–20 times lower (0.001–0.007 mg CH4-C•m−2•h−1) than daily average CH4 uptake by control soils (0.015–0.035 mg CH4-C•m−2•h−1). We also measured the relative activities of the bacteria populations that were responsible for CH4 oxidation in the control and fertilized soils. Results from these measurements suggest that fertilization shifted the relative activities of the CH4 oxidizing bacteria from those dominated by methanotrophs in the control soils to those dominated by nitrifying bacteria in the surface (0–2 cm) of the fertilized soils. The shift in relative activities of these bacteria may have been responsible for the lower CH4 uptake by the fertilized soils.
Alternative volume and quantity formulas for individual trees
Authors: Deusen Paul C. Van
Published: May 2008

General definitions of volume and quantity as multiple definite integrals are used as the basis for deriving alternative formulas that apply to individual trees. Some of these formulas are quite familiar to foresters, whereas others are new. Potential applications of these formulas in conjunction with importance sampling are discussed.
Productivity growth and price trends in the North American sawmilling industries: an inter-regional comparison
Authors: Abt Robert C. , Brunet Jamie , Murray Brian C. , Roberts Don G.
Published: May 2008

This paper applies nonparametric superlative index techniques to measure productivity growth in the sawmilling industries of the United States and Canada. Six geographic regions are examined: British Columbia (Coast and Interior), Ontario, Quebec, U.S. South, and U.S. West. The results indicate significant adjustment of resources both within and across regional industries over time. Over the long-term, labor has been the input that has experienced the highest growth in productivity: 3–4% per annum in the commodity-oriented regions. This result likely reflects the significant increases in capital stock throughout most of the North American industry. From 1980 to 1988 there have been significant differences in the annualized growth rates in total factor productivity across regions: U.S. West (3.3%), B.C. Interior (2.7%), Quebec (1.9%), U.S. South (1.4%), B.C. Coast (1.3%), and Ontario (1.1%). However, growth in total factor productivity over the 24-year period from 1965 to 1988 is relatively uniform across most regions (1.2% per annum).
Quantitative genetics of yield breeding for Populus short-rotation culture. II. Genetic determination and expected selection response of tree geometry
Authors: Wu Rong-Ling
Published: May 2008

Understanding the genetic determination of tree geometry and its associations with productivity are important research goals of short rotation intensive culture of fast-growing Populus species. A morphological development model of a 4-year Populus deltoïdes Bartr. × Populussimonii Carr. and P. deltoids × Populusnigra L. F1 hybrid poplar was described at four levels of organization: (i) leaf, (ii) branch, (iii) main stem, and (iv) whole tree. Quantitative genetic analyses were done to explore the amounts and patterns of genetic variation and responses to artificial selection for 58 morphometric traits at the four levels. Leaf traits were compared across current terminal, sylleptic and proleptic branches, and pooled type; branch traits were compared across sylleptic and proleptic branches and pooled type. The alternate locations of sylleptics with proleptics on the main stem was considered to be an adaptive response of poplars to environmental conditions in the middle temperate zones. The components of tree geometry showed abundant genetic variation among clones and high broad-sense heritability levels, both with apparent divergence across traits, trait origins (for leaf and branch traits), and hybrid populations. Desired trait such as main stem height and diameter at breast height had decreased genetic bases and, thus, decreased selection responses compared with other morphometric traits. Despite weaker genetic control over leaf and branch traits on sylleptics than on current terminal and proleptics, high genetic variabilities would be expected to generate substantial genetic gain for some traits such as leaf number, size, and orientation on sylleptic branches. Under moderate selective intensity (p = 15%), P. deltoids × P. simonii tended to display more open branching systems with great photosynthetic area and light interception, while tree geometry of P. deltoids × P. nigra showed a better balance between maximum photosynthetic organ production and minimum energy investment.
Production function for short-rotation woody-crop Populus spp. plantations
Authors: Lortz David A. , Betters David R. , Wright Lynn L.
Published: May 2008

Short-rotation woody-crop Populus spp. plantations have the potential to produce large amounts of biomass in short time periods, typically 4–8 years. A production function equation is shown to predict yields for such plantations. The equation is based, in part, on information from biomass production experiments conducted across the United States. These experimental plots are sponsored by the Biofuels Feedstock Development Program of Oak Ridge National Laboratory. The equation uses nine parameters including both cultural practices and climatic and soil site conditions as independent variables. The equation (R2 = 0.86) is accurate and applicable to a wide range of conditions.
QUANTIZATION OF CHIRAL ANTISYMMETRIC TENSOR FIELDS
Authors: WETTERICH C.
Published: May 2008

Chiral antisymmetric tensor fields can have chiral couplings to quarks and leptons. Their kinetic terms do not mix different representations of the Lorentz symmetry and a local mass term can be forbidden by symmetry. The chiral couplings to the fermions are asymptotically free, opening interesting perspectives for a possible solution to the gauge hierarchy problem. We argue that the interacting theory for such fields can be consistently quantized, in contrast to the free theory which is plagued by unstable solutions. We suggest that at the scale where the chiral couplings grow large the electroweak symmetry is spontaneously broken and a mass term for the chiral tensors is generated nonperturbatively. Massive chiral tensors correspond to massive spin-one particles that do not have problems of stability. We also propose an equivalent formulation in terms of gauge fields.
N-symmetry direction field design
Authors: Ray Nicolas , Vallet Bruno , Li Wan Chiu , Lévy Bruno
Published: May 2008

Many algorithms in computer graphics and geometry processing use two orthogonal smooth direction fields (unit tangent vector fields) defined over a surface. For instance, these direction fields are used in texture synthesis, in geometry processing or in nonphotorealistic rendering to distribute and orient elements on the surface. Such direction fields can be designed in fundamentally different ways, according to the symmetry requested: inverting a direction or swapping two directions might be allowed or not.

Despite the advances realized in the last few years in the domain of geometry processing, a unified formalism is still lacking for the mathematical object that characterizes these generalized direction fields. As a consequence, existing direction field design algorithms are limited to using nonoptimum local relaxation procedures.

In this article, we formalize
N
-symmetry direction fields, a generalization of classical direction fields. We give a new definition of their singularities to explain how they relate to the topology of the surface. Specifically, we provide an accessible demonstration of the Poincaré-Hopf theorem in the case of
N
-symmetry direction fields on 2-manifolds. Based on this theorem, we explain how to control the topology of
N
-symmetry direction fields on meshes. We demonstrate the validity and robustness of this formalism by deriving a highly efficient algorithm to design a smooth field interpolating user-defined singularities and directions.
Transmembrane IV of the high-affinity sodium-glucose cotransporter participates in sugar binding
Authors: Liu Tiemin , Lo Bryan , Speight Pam , Silverman Mel
Published: May 2008

Investigation of the structure/function relationships of the sodium-glucose transporter (SGLT1) is crucial to understanding the cotransporter mechanism. In the present study, we used cysteine-scanning mutagenesis and chemical modification by methanethiosulfonate (MTS) derivatives to test whether predicted transmembrane IV participates in sugar binding. Five charged and polar residues (K139, Q142, T156, K157, and D161) and two glucose/galactose malabsorption missense mutations (I147 and S159) were replaced with cysteine. Mutants I147C, T156C, and K157C exhibited sufficient expression to be studied in detail using the two-electrode voltage-clamp method in Xenopus laevis oocytes and COS-7 cells. I147C was similar in function to wild-type and was not studied further. Mutation of lysine-157 to cysteine (K157C) causes loss of phloridzin and α-methyl-d-glucopyranoside (αMG) binding. These functions are restored by chemical modification with positively charged (2-aminoethyl) methanethiosulfonate hydrobromide (MTSEA). Mutation of threonine-156 to cysteine (T156C) reduces the affinity of αMG and phloridzin for T156C by ∼5-fold and ∼20-fold, respectively. In addition, phloridzin protects cysteine-156 in T156C from alkylation by MTSEA. Therefore, the presence of a positive charge or a polar residue at 157 and 156, respectively, affects sugar binding and sugar-induced Na+ currents.
Cannabinoid-1 receptor antagonists reduce caloric intake by decreasing palatable diet selection in a novel dessert protocol in female rats
Authors: Mathes Clare M. , Ferrara Marco , Rowland Neil E.
Published: May 2008

Although many feeding protocols induce obesity, few use multiple foods to analyze diet selection within a single group of animals. To this end, we describe a protocol using time-limited access to a dessert that induces hyperphagia and body weight gain while allowing simple analysis of diet selection. Female retired breeder Sprague-Dawley rats were provided with ad libitum access to standard moist chow (1.67 kcal/g) and daily 8-h nocturnal access to either a sugar gel (SG; 0.31 kcal/g) or sugar fat whip (SFW; 7.35 kcal/g) for 15 days, and food intake and body weight were measured daily. Rats given SFW reduced moist chow intake but not enough to compensate for the large amount of calories consumed from SFW, and thus gained weight. We use this SFW overconsumption protocol to investigate the hypothesis that cannabinoid (CB)1 receptor antagonists reduce caloric intake by selectively decreasing consumption of palatable foods. In two experiments, female retired breeder Sprague-Dawley rats were injected with either Rimonabant (1 mg/kg ip) or vehicle (equal parts polyethylene glycol and saline, 1 ml/kg ip) for 7 days, or one of three doses of AM251 (0.3, 1.0, or 3.0 mg/kg ip), or vehicle for 15 days; food intake and body weight were measured daily. Both Rimonabant and AM251 decreased 24-h caloric intake, but the reduction was specific to a decrease in SFW consumption. This supports the hypothesis that these CB1 receptor antagonists impact feeding by modulating the perception of palatability.
An imprinted gene network that controls mammalian somatic growth is down-regulated during postnatal growth deceleration in multiple organs
Authors: Lui Julian C. , Finkielstain Gabriela P. , Barnes Kevin M. , Baron Jeffrey
Published: May 2008

In mammals, somatic growth is rapid in early postnatal life but decelerates with age and eventually halts, thus determining the adult body size of the species. This growth deceleration, which reflects declining proliferation, occurs simultaneously in multiple organs yet appears not to be coordinated by a systemic mechanism. We, therefore, hypothesized that growth deceleration results from a growth-limiting genetic program that is common to multiple tissues. Here, we identified a set of 11 imprinted genes that show down-regulation of mRNA expression with age in multiple organs. For these genes, Igf2, H19, Plagl1, Mest, Peg3, Dlk1, Gtl2, Grb10, Ndn, Cdkn1c, and SLC38a4, the declines show a temporal pattern similar to the decline in growth rate. All 11 genes have been implicated in the control of cell proliferation or somatic growth. Thus, our findings suggest that the declining expression of these genes contributes to coordinate growth deceleration in multiple tissues. We next hypothesized that the coordinate decline in expression of these imprinted genes is caused by altered methylation and consequent silencing of the expressed allele. Contrary to this hypothesis, the methylation status of the promoter regions of Mest, Peg3, and Plagl1 did not change with age. Our findings suggest that a set of growth-regulating imprinted genes is expressed at high levels in multiple tissues in early postnatal life, contributing to rapid somatic growth, but that these genes are subsequently downregulated in multiple tissues simultaneously, contributing to coordinate growth deceleration and cessation, thus imposing a fundamental limit on adult body size.
Inflammation is associated with a decrease of lipogenic factors in omental fat in women
Authors: Poulain-Godefroy Odile , Lecoeur Cécile , Pattou François , Frühbeck Gema , Froguel Philippe
Published: May 2008

Obesity is characterized by systemic low-grade inflammation in which adipose tissue, especially the omental depot, is thought to play a key role. We have previously shown that inflammation impairs 3T3-L1 preadipocyte cell line differentiation. To explore whether this interaction also takes place in vivo, the expression of several genes related to inflammation and adipocyte differentiation was assessed in human samples. Paired adipose tissue biopsies (from omental and subcutaneous depots) were obtained from 24 women: 6 lean normoglycemic and 18 obese volunteers with different glycemic states (normoglycemic, glucose-intolerant, or type 2 diabetic). The expression levels of CD14, IL-18, leptin, adiponectin, sterol regulatory element binding transcription factor 1 (SREBP1), peroxisome proliferator-activated receptor gamma (PPARγ), pre-B-cell colony enhancing factor 1 (PBEF1) (or visfatin), glycerol-3-phosphate dehydrogenase 1 (soluble) (GPD1), lipoprotein lipase (LPL), fatty acid binding protein 4, adipocyte (FABP4), and hypoxia-inducible factor 1α were determined by quantitative real-time PCR. CD14 and IL-18 were overexpressed in omental adipose tissue compared with the subcutaneous depot, irrespective of the subject's obesity or diabetes status. A significant decrease of LPL, GPD1, and leptin expression was observed in omental tissue, and an inverse correlation between expression of CD14 and IL-18 and that of PPARγ, LPL, and FABP4 was observed. The underexpression of omental lipogenic markers was more accentuated in the presence of glucose intolerance. Furthermore, adiponectin and SREBP1 expression was also significantly decreased in omental tissue of type 2 diabetic patients. PBEF1 and HIF1α expression remained comparable in all samples. Therefore, in humans, inflammation is increased in the omental depot, as evidenced by CD14 and IL-18 expression. In this localization, the inflammatory state is associated with a decreased expression of lipogenic markers, which is more pronounced in diabetic subjects.
Silencing megalin and cubilin genes inhibits myeloma light chain endocytosis and ameliorates toxicity in human renal proximal tubule epithelial cells
Authors: Li Min , Balamuthusamy Saravanan , Simon Eric E. , Batuman Vecihi
Published: May 2008

Using target-specific short interfering (si) RNAs, we silenced the tandem endocytic receptors megalin and cubilin genes in cultured human renal proximal tubule epithelial cells. Transfection by siRNA resulted in up to 90% suppression of both megalin and cubilin protein and mRNA expression. In HK-2 cells exposed to κ-light chain for up to 24 h, light chain endocytosis was reduced in either megalin- or cubilin-silenced cells markedly but incompletely. Simultaneous silencing of both the cubilin and megalin genes, however, resulted in near-complete inhibition of light chain endocytosis, as determined by measuring κ-light chain protein concentration in cell cytoplasm and by flow cytometry using FITC-labeled κ-light chain. In these cells, light chain-induced cytokine responses (interleukin-6 and monocyte chemoattractant protein-1) and epithelial-to-mesenchymal transition as well as the associated cellular and morphological alterations were also markedly suppressed. The results demonstrate that light chain endocytosis is predominantly mediated by the megalin-cubilin tandem endocytic receptor and identify endocytosis as a key step in light chain cytotoxicity. Blocking light chain endocytosis prevents its nephrotoxic effects on human kidney proximal tubule cells.
Acute inhibition of the betaine transporter by ATP and adenosine in renal MDCK cells
Authors: Kempson Stephen A. , Edwards Jason M. , Osborn Alyssa , Sturek Michael
Published: May 2008

Extracellular ATP interacts with purinergic P2 receptors to regulate a range of physiological responses, including downregulation of transport activity in the nephron. ATP is released from cells by mechanical stimuli such as cell volume changes, and autocrine signaling by extracellular ATP could occur in renal medullary cells during diuresis. This was tested in Madin-Darby canine kidney (MDCK) cells, a model used frequently to study P1 and P2 receptor activity. ATP was released within 1 min after transfer from 500 to 300 mosmol/kgH2O medium. A 30-min incubation with ATP produced dose-dependent inhibition (0.01–0.10 mM) of the renal betaine/GABA transporter (BGT1) with little effect on other osmolyte transporters. Inhibition was reproduced by specific agonists for P2X (α,β-methylene-ATP) and P2Y (UTP) receptors. Adenosine, the final product of ATP hydrolysis, also inhibited BGT1 but not taurine transport. Inhibition by ATP and adenosine was blocked by pertussis toxin and A73122, suggesting involvement of inhibitory G protein and PLC in postreceptor signaling. Both ATP and adenosine (0.1 mM) produced rapid increases in intracellular Ca2+, due to the mobilization of intracellular Ca2+stores and Ca2+influx. Blocking these Ca2+increases with BAPTA-AM also blocked the action of ATP and adenosine on BGT1 transport. Finally, immunohistochemical studies indicated that inhibition of BGT1 transport may be due to endocytic accumulation of BGT1 proteins from the plasma membrane. We conclude that ATP and adenosine, through stimulation of PLC and intracellular Ca2+, may be rapidly acting regulators of BGT1 transport especially in response to a fall in extracellular osmolarity.
Brain cell volume regulation in hyponatremia: role of sex, age, vasopressin, and hypoxia
Authors: Ayus Juan Carlos , Achinger Steven G. , Arieff Allen
Published: May 2008

Hyponatremia is the most common electrolyte abnormality in hospitalized patients. When symptomatic (hyponatremic encephalopathy), the overall morbidity is 34%. Individuals most susceptible to death or permanent brain damage are prepubescent children and menstruant women. Failure of the brain to adapt to the hyponatremia leads to brain damage. Major factors that can impair brain adaptation include hypoxia and peptide hormones. In children, physical factors—discrepancy between skull size and brain size—are important in the genesis of brain damage. In adults, certain hormones—estrogen and vasopressin (usually elevated in cases of hyponatremia)—have been shown to impair brain adaptation, decreasing both cerebral blood flow and oxygen utilization. Initially, hyponatremia leads to an influx of water into the brain, primarily through glial cells and largely via the water channel aquaporin (AQP)4. Water is thus shunted into astrocytes, which swell, largely preserving neuronal cell volume. The initial brain response to swelling is adaptation, utilizing the Na+-K+-ATPase system to extrude cellular Na+. In menstruant women, estrogen + vasopressin inhibits the Na+-K+-ATPase system and decreases cerebral oxygen utilization, impairing brain adaptation. Cerebral edema compresses the respiratory centers and also forces blood out of the brain, both lowering arterial Po2 and decreasing oxygen utilization. The hypoxemia further impairs brain adaptation. Hyponatremic encephalopathy leads to brain damage when brain adaptation is impaired and is a consequence of both cerebral hypoxia and peptide hormones.
Custom Hardware Processor to Compute a Figure of Merit for the Fit of X‐Ray Diffraction Peaks
Authors: Gomez-Pulido Juan A. , Sanchez-Bajo Florentino , Pereira dos Santos Sidolina , Vega-Rodriguez Miguel A. , Sanchez-Perez Juan M.
Published: May 2008

A custom processor
based on reconfigurable hardware technology is
proposed in order to compute the figure of merit
used to measure the quality of the fit of
X‐ray diffraction peaks. As the experimental
X‐ray profiles can present many peaks severely
overlapped, it is necessary to select the best
model among a large set of reasonably good
solutions. Determining the best solution is
computationally intensive, because this is a
hard combinatorial optimization problem. The
proposed processors, working in parallel,
increase the performance relative to a software
implementation.
On Controllability and Observability of Fuzzy Dynamical Matrix Lyapunov Systems
Authors: Murty M. S. N. , Kumar G. Suresh
Published: May 2008

We provide a way to combine matrix Lyapunov systems
with fuzzy rules to form a new fuzzy system called fuzzy dynamical matrix
Lyapunov system, which can be regarded as a new approach to intelligent
control. First, we study the controllability property of the fuzzy dynamical
matrix Lyapunov system and provide a sufficient condition for its controllability
with the use of fuzzy rule base. The significance of our result is that given
a deterministic system and a fuzzy state with rule base, we can determine the
rule base for the control. Further, we discuss the concept of observability and
give a sufficient condition for the system to be observable. The advantage of
our result is that we can determine the rule base for the initial value without
solving the system.
A Theoretical Framework for Quality‐Aware Cross‐Layer Optimized Wireless Multimedia Communications
Authors: Ci Song , Wang Haohong , Wu Dalei
Published: May 2008

Although cross‐layer has been thought as one of the most effective and efficient ways for multimedia communications over wireless networks and a plethora of research has been done in this area, there is still lacking of a rigorous mathematical model to gain in‐depth understanding of cross‐layer design tradeoffs, spanning from application layer to physical layer. As a result, many existing cross‐layer designs enhance the performance of certain layers at the price of either introducing side effects to the overall system performance or violating the syntax and semantics of the layered network architecture. Therefore, lacking of a rigorous theoretical study makes existing cross‐layer designs rely on heuristic approaches which are unable to guarantee sound results efficiently and consistently. In this paper, we attempt to fill this gap and develop a new methodological foundation for cross‐layer design in wireless multimedia communications. We first introduce a delay‐distortion‐driven cross‐layer optimization framework which can be solved as a large‐scale dynamic programming problem. Then, we present new approximate dynamic programming based on significance measure and sensitivity analysis for high‐dimensional nonlinear cross‐layer optimization in support of real‐time multimedia applications. The major contribution of this paper is to present the first rigorous theoretical modeling for integrated cross‐layer control and optimization in wireless multimedia communications, providing design insights into multimedia communications over current wireless networks and throwing light on design optimization of the next‐generation wireless multimedia systems and networks.
Phylogenetic Analyses: A Toolbox Expanding towards Bayesian Methods
Authors: Aris-Brosou Stéphane , Xia Xuhua
Published: May 2008

The reconstruction of phylogenies is becoming an increasingly simple activity. This is mainly due to two reasons: the democratization of computing power and the increased availability of sophisticated yet user-friendly software. This review describes some of the latest additions to the phylogenetic toolbox, along with some of their theoretical and practical limitations. It is shown that Bayesian methods are under heavy development as they offer the possibility to solve a number of long-standing issues and to integrate several steps of the phylogenetic analyses into a single framework. Specific topics include not only phylogenetic reconstruction, but also the comparison of phylogenies, the detection of adaptive evolution, and the estimation of divergence times between species.
Hollow Disc and Sphere-Shaped Particles from Red Blood Cell Templates
Authors: Landon Preston B. , Gutierrez Jose J. , Alvarado Sara A. , Peela Sujatha , Ramachandran Srinivasan , Arce Fernando Teran , Lal Ratnesh
Published: May 2008

Colloidal gold particles with uniform size distributions were fabricated utilizing human red blood cells (RBCs) as templates. The gold shells were charged with a metal chelating agent to prevent flocculation. The procedure described here allows control over the shape of the colloidal particles. Thus, it was possible to fabricate discs and spheres by controlling the osmotic pressure.
Natural Circulation Characteristics at Low-Pressure Conditions through PANDA Experiments and ATHLET Simulations
Authors: Paladino Domenico , Huggenberger Max , Schäfer Frank
Published: May 2008

Natural circulation characteristics at low pressure/low power have been studied by performing experimental investigations and numerical simulations. The PANDA large-scale facility was used to provide valuable, high quality data on natural circulation characteristics as a function of several parameters and for a wide range of operating conditions. The new experimental data allow for testing and improving the capabilities of the thermal-hydraulic computer codes to be used for treating natural circulation loops in a range with increased attention. This paper presents a synthesis of a part of the results obtained within the EU-Project NACUSP “natural circulation and stability performance of boiling water reactors.” It does so by using the experimental results produced in PANDA and by showing some examples of numerical simulations performed with the thermal-hydraulic code ATHLET.
Approximation of Generalized Left Derivations
Authors: Kang Sheon-Young , Chang Ick-Soon
Published: May 2008

We need to take account of the superstability for generalized left
derivations (resp., generalized derivations) associated with a Jensen‐type
functional equation, and we also deal with problems for the Jacobson radical
ranges of left derivations (resp., derivations).
Proton Pump Inhibitors for Dyspepsia
Authors: Vakil Nimish
Published: May 2008

Proton pump inhibitors are widely used in many upper gastrointestinal disorders. Dyspepsia is a common problem in primary care and endoscopy is neither feasible nor affordable in the majority of patients. Helicobacter pylori eradication has been shown to be effective, but with the declining prevalence of H. pylori infection in Western countries, alternate strategies are necessary. Proton pump inhibitor therapy is one such alternative and has already been adopted in dyspepsia management guidelines in the USA, UK and Canada. Cost-effectiveness studies suggest that in young patients acid suppression alone is more cost-effective than either endoscopy or testing and treatment for H. pylori in areas with a low prevalence of H. pylori.
Recruitment and in situ Renewal Regulate Rapid Accumulation of CD11c+ Cells in the Lung following Intranasal Superantigen Challenge
Authors: Muralimohan Guruprasaadh , Rossi Robert J. , Vella Anthony T.
Published: May 2008

Background: Staphylococcusaureus, a primary source of bacterial superantigen, is known to colonize the human respiratory tract and has been implicated in airway inflammation. The potential pathological effect of staphylococcal enterotoxins on the respiratory tract necessitates a detailed understanding of how they regulate innate immune cells, particularly CD11c-expressing dendritic cells (DCs). Methods: C57BL/6 mice were challenged intranasally with staphylococcal enterotoxin A (SEA) and at indicated time points lung tissue was perfused, digested and analyzed for CD11c+ expressing cells. Results: The pulmonary CD11c+ cells can be divided into two major populations based on their MHC II expression. One day following intranasal SEA challenge, there was rapid accumulation of CD11c+ cells expressing medium to high levels of MHC II. The peak accumulation of CD11c+ MHC II– population was observed 2 days after SEA challenge; however, careful examination of this cell population revealed that they were heterogeneous, being comprised of cells bearing CD3, CD19, NK1.1 and F4/80 along with varying levels of CD11c. Nevertheless, there was a 2-fold increase of CD11c+ MHC II– (CD3– CD19– NK1.1– F4/80–) cells in the lungs. Conclusion: The mechanism of increase in the CD11c+ MHC II– immune progenitor population was mainly due to cellular division rather than migration from blood to lung. In contrast, the early and rapid accumulation of CD11c+ MHC IIhi cells, conventionally known as DCs, in the lung on day 1 was mostly due to migration from blood. Thus this study examines the pulmonary innate immune response to a powerful immune stimulus.
Medial Olivocochlear Functioning and Speech Perception in Noise in Older Adults
Authors: Mukari Siti Zamratol-Mai Sarah , Mamat Wan Hasyimah Wan
Published: May 2008

The purposes of this study were to: (1) compare medial olivocochlear system (MOCS) functioning and speech perception in noise in young and older adults and (2) to quantify the correlation between MOCS functioning and speech perception in noise. Measurements were taken in 20 young (mean 26.3 ± 2.1 years) and 20 older adults (mean 55.2 ± 2.8 years). Contralateral distortion product otoacoustic emission (DPOAE) suppression was measured to assess MOCS functioning. Speech perception in noise was evaluated using the Hearing in Noise Test in noise-ipsilateral, noise-front and noise-contralateral test conditions. The results revealed that the older group had a significantly lower high-frequency (3–8 kHz) contralateral DPOAE suppression, and performed more poorly in the noise-ipsilateral condition than the younger group. However, there was no correlation between contralateral DPOAE suppression and speech perception in noise. This study suggests that poor speech perception performance in noise experienced by older adults might be due to a decline in medial olivocochlear functioning, among other factors.
Clarithromycin for 2 Weeks for Stable Coronary Heart Disease: 6-Year Follow-Up of the CLARICOR Randomized Trial and Updated Meta-Analysis of Antibiotics for Coronary Heart Disease
Authors: Gluud Christian , Als-Nielsen Bodil , Damgaard Morten , Fischer Hansen Jørgen , Hansen Stig , Helø Olav H. , Hildebrandt Per , Hilden Jørgen , Jensen Gorm Boje , Kastrup Jens , Kolmos Hans Jørn , Kjøller Erik , Lind Inga , Nielsen Henrik , Petersen Lars , Jespersen Christian M.
Published: May 2008

Objectives: We have reported increased 2.6-year mortality in clarithromycin- versus placebo-exposed stable coronary heart disease patients, but meta-analysis of randomized trials in coronary heart disease patients showed no significant effect of antibiotics on mortality. Here we report the 6-year mortality of clarithromycin- versus placebo-exposed patients and updated meta-analyses. Methods: Centrally randomized, placebo controlled multicenter trial. All parties were blinded. Analyses were by intention to treat. Meta-analyses followed the Cochrane Collaboration methodology. Results: We randomized 4,372 patients with stable coronary heart disease to clarithromycin 500 mg (n = 2,172) or placebo (n = 2,200) once daily for 2 weeks. Mortality was followed through public register. Nine hundred and twenty-three patients (21.1%) died. Six-year mortality was significantly higher in the clarithromycin group (hazard ratio 1.21, 95% confidence interval 1.06–1.38). Adjustment for entry characteristics (sex, age, prior myocardial infarction, center, and smoking) did not change the results (1.18, 1.04–1.35). Addition of our data to that of other randomized trials on antibiotics for patients with coronary heart disease versus placebo/no intervention (17 trials, 25,271 patients, 1,877 deaths) showed a significantly increased relative risk of death from antibiotics of 1.10 (1.01–1.20) without heterogeneity. Conclusions: Our results stress the necessity to consider carefully the strength of the indication before administering antibiotics to patients with coronary heart disease.
Seasonality and Climatic Associations with Violent and Nonviolent Suicide: A Population-Based Study
Authors: Lin Herng-Ching , Chen Chin-Shyan , Xirasagar Sudha , Lee Hsin-Chien
Published: May 2008

Background: Using 7-year population-based data on Taiwan, we examined seasonal variation in violent versus nonviolent suicide, and its association with meteorological factors: ambient temperature, relative humidity, atmospheric pressure, rainfall and daily sunshine hours. Methods: We used Taiwan’s nationwide mortality data from 1997 to 2003, categorizing the sample decedents into two groups, violent (ICD-9-CM codes E953–E958) and nonviolent (E950–E952) suicide, based on the suicide method used. Seasonal autoregressive integrated moving average (SARIMA) modeling was used to detect seasonality of suicide, and the association of climate variables with violent versus nonviolent suicide. Results: The SARIMA test of seasonality was significant for both genders and the pooled sample (all p < 0.001) in violent suicide deaths, but not nonviolent suicides. Seasonal trends show a significant peak in March–May (early to late spring) for violent suicides. Increasing ambient temperature predicted increasing violent suicide rates. Conclusions: We conclude that seasonality exists in violent but not nonviolent suicide rates. Our findings suggest that suicide is a heterogeneous phenomenon and violent suicide may be more influenced by biochemical and chronobiological mechanisms.
Erdheim-Chester Disease: Pulmonary Presentation in a Case with Advanced Systemic Involvement
Authors: Protopapadakis Charalambos , Antoniou Katerina M. , Nicholson Andrew G. , Voloudaki Argiro , Tzanakis Nikolaos , Karantanas Athanasios , Siafakas Nikolaos M.
Published: May 2008

Erdheim-Chester disease (ECD) is a non-Langerhans cell histiocytosis usually affecting bone, that may progress to multi-organ involvement, with pulmonary involvement as an indicator of poor prognosis. Herein, we present a 48-year-old man with a 2-year history of progressive exertional dyspnoea, dry cough, malaise and exophthalmos. High-resolution computed tomography showed peripheral interstitial thickening with a lymphangitic distribution throughout both lungs, suspected of representing lymphangitic spread of neoplasia. Transbronchial biopsy specimen and bronchoalveolar lavage were non-diagnostic; thus, a surgical lung biopsy was performed which showed features diagnostic of ECD. Subsequent systematic investigations showed widespread bone involvement, cardiac involvement manifested as left heart failure and renal/perirenal disease. Treatment with pulsed corticosteroids and cyclophosphamide elicited neither clinical nor functional response, with death at 6 months. This case highlights the aggressive nature of ECD when there is pulmonary involvement, as well as problems in diagnosis when there is pulmonary presentation and when systemic disease is asymptomatic.
X inactivation, differentiation, and DNA methylation
Authors: Riggs A.D.
Published: May 2008

A model based on DNA methylation is proposed to explain the initiation and maintenance of mammalian X inactivation and certain aspects of other permanent events in eukaryotic cell differentiation. A key feature of the model is the proposal of sequence-specific DNA methylases that methylate unmethylated sites with great difficulty but easily methylate half-methylated sites. Although such enzymes have not yet been detected in eukaryotes, they are known in bacteria. An argument is presented, based on recent data on DNA-binding proteins, that DNA methylation should affect the binding of regulatory proteins. In support of the model, short reviews are included covering both mammalian X inactivation and bacterial restriction and modification enzymes.
Cytogenetic studies in control men and women
Authors: Littlefield Gayle , Goh K.-O.
Published: May 2008

Cytogenetic analyses of 11,950 lymphocyte metaphases from 122 cultures from 10 control men and 17,759 lymphocyte metaphases from 183 cultures from 21 control women have shown: (1) variations in breakage frequencies in consecutive cultures from the same person, (2) variations in average breakages among cultures from different people, (3) greater variability in breakages in cultures from women than in cultures from men, and (4) differences in average breakage frequencies in cultures obtained at different times of the year.
Evidence against the peripheral location of the Y chromosome in human metaphase cells
Authors: Spence Anne , Francke Uta , Forsythe A.B.
Published: May 2008

It has been reported that the Y chromosome consistently assumes a peripheral location in metaphase cells. Analysis of two normal males and an XYY individual revealed no evidence to support this contention.
X and Y chromosome pairing and disjunction in a male mouse with an XYY sex-chromosome constitution
Authors: Rathenberg R. , Müller D.
Published: May 2008

In an albino mouse with the usual phenotypic appearance, an XYY polysomy was observed in the germinal epithelium. Analysis of all three metaphase stages verified this observation. At metaphase I, in addition to XYY, XYY, and XYY bi- and univalent groupings, XYY trivalent configurations were present. The data indicated randomness in association of the X and Y and random segregation of the three chromosomes. From the relative frequency of the different metaphase stages, it was concluded that only a fraction of the metaphase I cells reached metaphase II.
Replication pattern and quinacrine fluorescence of the chromosomes of a CV-1-derived African green monkey cell line
Authors: Parker R.J. , Allderdice P.W. , Miller O.J. , Schildkraut C.L.
Published: May 2008

When tritiated thymidine is incorporated into cells of a heteroploid CV-1-derived line near the end of the DNA synthetic period (S), the chromosomes are preferentially labeled in the centromeric region. After staining with quinacrine, the centromeric region of every chromosome shows minimal fluorescence, whereas the remainder of most chromosomes shows fairly bright fluorescence with distinctive banding patterns. In contrast to the end-of-S pattern, the distribution of grains over chromosomes labeled during the middle of S is consistent with random labeling. A marker chromosome with a long secondary constriction in the long arm near the centromere possesses the same labeling pattern, with late replication limited to the centromeric region and perhaps the adjacent region of the short arm. The secondary constriction region itself is not late replicating, and it fails to fluoresce after quinacrine staining.