bluuebunny/crossref_metadata_2025 huggingface dataset:
A Digital Compensator Design for Electrohydraulic Single-Rod Cylinder Position Control Systems
Authors: Watton J.
Published: March 2008

A digital compensator using a forward algorithm, F(z−1), and a feedback algorithm, H(z−1), is developed for an electrohydraulic position control system incorporating an underlapped servovalve and a single-rod cylinder. The main problems encountered with designing such a closed-loop system are discussed, and it is shown how the filter coefficients may be easily determined for a particular class of open-loop transfer function. An excellent comparison between theory and experiment is obtained and it is deduced that one coefficient only need be changed in the forward algorithm for such gain-change dominant systems.
A Frequency Domain Identification Scheme for Flexible Structure Control
Authors: Tzes A. P. , Yurkovich S.
Published: March 2008

Transfer function identification schemes for use in self-tuning control applications are considered. Frequency domain methods generally require less computational load than time domain methods, and for certain classes of systems may be more accurate. For control purposes, however, a time domain parameterization of the system transfer function is often preferred, because of the direct relationship to controller parameters. In this paper we present a new method called Time-varying Transfer Function Estimation (TTFE) in which system parameters are computed through identification in the frequency domain. The method is particularly well suited for flexible structure control problems, and a self-tuning control law with frequency shaping is derived and demonstrated on a flexible manipulator system.
Design Principles for Vibration Control Systems Using Semi-Active Dampers
Authors: Karnopp D.
Published: March 2008

Electronically controlled vibration isolation and control systems have recently reached at least the prototype phase in a number of fields of application. Of particular practical interest are semi-active systems which require very little actuator power. Semi-active dampers in the form of rapidly modulated hydraulic shock absorbers have been used for example in automobile suspensions to achieve some of the benefits of fully active servo-mechanism systems but with much reduced cost and complexity. Various damper configurations and feedback control schemes are discussed. The design choices to be made can often result in similar system performance and yet can lead to dramatic differences in the frequency response requirements for the actuators used in the semi-active dampers.
The Utilization of Experimental Data in Modelling Hydraulic Single Stage Pressure Control Valves
Authors: Handroos H. M. , Vilenius M. J.
Published: March 2008

Low-order nonlinear models for single stage pressure relief and pressure reducing valves are developed and subjected to experimental verification. The form of both models is postulated by an appeal to physical principles, but the parameter values are identified with the help of simple numerical methods using measured characteristic curves.
A Solution for the Force Distribution Problem in Redundantly Actuated Closed Kinematic Chains
Authors: Gardner J. F. , Srinivasan K. , Waldron K. J.
Published: March 2008

Proper control of robotic systems which incorporate closed kinematic chains is important in many applications. Among these are the multi-robot work cell and legged vehicles. In these no unique solution exists for the force distribution corresponding to a specified trajectory. A framework within which additional constraint equations may be written is presented here, and the force distribution solved in closed form for a walking machine application. These constraints are related to system performance goals of interest, such as improved traction and/or load sharing among the legs. The proposed technique is shown to be computationally simpler than other alternative solutions to the same problem.
Variations in aphid transmission of leaf roll virus to and from potato
Authors: MacKinnon J. P.
Published: March 2008

As many potato seedlings became infected with leaf roll virus when infested with viruliferous aphids (Myzus persicae Sulz.) by a fast cut-leaf method, as when infested by a slower brush method. More plants, however, became infected when infested at emergence than at any of five other periods of growth including that of sprouts.In recovery tests, more infected plants were detected by testing sprouts and excised leaves of 7-week-old plants than by testing newly emerged plants. Any of the small leaves from the upper 6 cm of infected plants were equally good sources of virus for aphids. Also, when tests were made for 18 successive weeks after inoculation on infected Netted Gem plants, it was only during the first 9 weeks and at the 13th week that all infected plants were detected.No differences resulted, in the number of infected plants produced, when eyes were grown from the bud or stem end or from the middle of infected tubers.
The site and chemical nature of red pigmentation in seedlings
Authors: Nozzolillo Constance
Published: March 2008

Hypocotyls of 76 species of dicotyledonous seedlings, drawn from 30 families, were surveyed for tissue site of red pigmentation. In 42 species, red pigments were borne by a single layer of cells. Two layers were pigmented in 19 species and several layers in 15. Hypocotyl extracts of 61 species were analyzed for anthocyanidins. Pelargonidin was the major pigment in only one. Cyanidin alone or in combination with pelargonidin or delphinidin was identified in 37 species and probably present in 11 more. Delphinidin and its derivatives malvidin and petunidin were found in members of the Solanaceae. Delphinidin and malvidin were also major pigments in two Phaseolus species. Anthocyanidins were not detected in the four members of the Centrospermae examined.
Genera coelomycetarum. II. Doliomyces
Authors: Raj T. R. Nag , Kendrick Bryce
Published: March 2008

The type species of Doliomyces, D. senegalensis, is redescribed. Doliomyces mysorensis sp. nov. is described from decaying leaves of Artocarpus integrifolia. Conidium ontogeny in this species is identical with that of some species of Pestalotia and Pestalotiopsis.
Production of perithecia by isolates of Gnomonia fructicola
Authors: Gourley C. O.
Published: March 2008

More isolates of Gnomonia fructicola formed perithecia on Leonian's agar than on potato-dextrose or cornmeal agar. Fortifying these media with a strawberry petiole extract stimulated perithecium formation on potato-dextrose agar but not on Leonian's or cornmeal agar. All eight isolates studied produced perithecia on strawberry petioles and one produced them only on petioles. The eight isolates segregated into four cultural races according to their ability to form perithecia on the agar media and petioles. This explains why different media have been reported to be best for perithecium production in this fungus.
Protein synthesis during gibberellin-induced germination of lettuce seed
Authors: Bewley J. Derek , Black M.
Published: March 2008

A study was made of gibberellin action on germinating lettuce seed. Results obtained by observing the total response of a seed population to the inhibitor cycloheximide could be interpreted as being indicative of gibberellin-induced protein synthesis. Biochemical studies did not substantiate this interpretation. Quantitative studies involving incorporation of leucine-4, 5-T in protein and qualitative studies using polyacrylamide gel electrophoresis suggest that there are no major GA-induced changes in protein synthesis before visible germination.
A model for cultivar classification and identification with reference to oats (Avena). I. Establishment of the groupings by taximetric methods
Authors: Baum B. R. , Lefkovitch L. P.
Published: March 2008

This paper describes the establishment and validation of 14 groupings of cultivars in the hexaploid cultivated oats. This study is based on 5000 samples from various parts of the world. In order to base the groupings on non-agronomic characters, 21 attributes, mainly micromorphological ones taken from floral parts such as lemmas, paleas, and lodicules, were examined and recorded. A divisive chain algorithm was devised for clustering 5000 individuals. The 107 clusters thus formed were then processed by single linkage, yielding 14 acceptable groupings; these were subsequently investigated by a canonical analysis. The procedural principles proposed are described and discussed.
Regeneration on Phycomyces sporangiophores. III. Grafting of sporangiophore segments, weight changes, and protoplasmic streaming in relation to regeneration
Authors: Gruen Hans E. , Ootaki Tamotsu
Published: March 2008

Decapitated 5-mm segments from stage 1 sporangiophores of Phycomyces blakesleeanus had similar regeneration capacity and polarity under room as under constant conditions. Regeneration on segments with whole apices was more frequent under room conditions despite resumption of apical elongation, but was only about half as frequent as on decapitated apical segments. Regeneration at incisions in the middle of stage 1 sporangiophores was rare unless cross walls formed at the incision. Sporangiophore halves and pairs of 5-mm segments were grafted successfully and cultured for 24 h. The protoplasts fused and a new wall rejoined the cut ends. Regeneration was rare on grafted sporangiophore halves. On grafts of decapitated, oppositely oriented segments regeneration was almost 100% and occurred mainly at the apical ends alone whether these were fused or free. On grafts of decapitated, normally oriented segments in normal or reversed order almost all anterior segments regenerated apically (as did the controls), but only half or fewer of the same segments in posterior position regenerated. Multiple regeneration and attainment of stage 4 were more frequent on anterior segments. Regeneration was less than 50% on grafts between segments with whole apices and basal segments, and on the latter was much less than on isolated controls.Movement of cytoplasm detectable by dry weight changes only occurred towards the regenerating end of segments after initiation of sporangiophores. The velocity of bidirectional protoplasmic streaming in segments increased during regeneration and was highest towards the basal non-regenerating end.The results of grafting do not support the hypothesis that an inhibitor from the apex normally suppresses regeneration (branching), but both suppression and induction of regeneration can be explained by a mechanism based on acropetal transport.
Characteristics of Drosera tentacles. I. Anatomical and cytological detail
Authors: Ragetli H. W. J. , Weintraub M. , Lo Esther
Published: March 2008

The area of merger between head and stalk was found to be anatomically much more diverse and to extend much deeper into the head than was previously thought. Interior cells of this transition zone, which we call the "neck area," were closely apposed to elements of the parenchyma bell of the head, and they contained many plasmodesmata in their walls. These features suggest that metabolites transported from the head to the leaf via the stalk largely follow an "interior route," especially since the inner stalk cells have some characteristics of conductive elements.The distinct cuticle, which covers the entire tentacle, was found to contain many pores in the area of the outer gland cells, with diameters up to 318 mμ. Complex tubular structures were detected in the outer pericline and upper anticline walls of the same cells. Together with the cuticle pores they were believed to account for the extreme permeability of the head.Intercellular spaces were detected in the middle and lower tentacle stalk. Since these spaces were not randomly distributed and were sometimes partially or completely closed, they were considered to be functional in tentacle bending.
Photosynthesis and metabolism of marine algae. VIII. Incorporation of 14C into the polysaccharides metabolized by Fucus vesiculosus during pulse labeling experiments
Authors: Bidwell R. G. S. , Percival Elizabeth , Smestad Berit
Published: March 2008

Samples of Fucus vesiculosus fronds were allowed to assimilate 14CO2 for 10 min and 3 h. In a second experiment fronds were allowed to grow for 10 min in 14CO2 and were then transferred to fresh medium containing 12CO2. Samples were taken immediately, after 30 min, and after 2 h. Sequential extraction and fractionation of the polysaccharides from each of the five samples gave 14C-labeled laminaran, xylogalactofucoglucuronan (A), xyloglucuronogalactofucan (B) (these polysaccharides are named in the order of the increasing proportions of their constituent sugars), fucoidan (C), alginic acid, and residual polysaccharide material containing mainly glucose with some galactose. The activities of each of the polysaccharides, the residual material, and their constituent sugars were measured. Highly active low molecular weight carbohydrates, present in the acid extract, are the suggested precursors of the polysaccharides. The fucose-containing polysaccharides represent the extremes of a family of polymers; it is postulated from these studies that (A) is transformed into fucoidan via polysaccharide (B) in this alga.
Histology of infection and sporulation by saprophytic cultures of Melampsora lini inoculated onto flax cotyledons in sterile culture
Authors: Turel Franziska L. M.
Published: March 2008

Saprophytic mycelium of the rust fungus Melampsora lini (Ehrenb.) Lév., race 3, invaded the wounded ends of detached cotyledons of Bison variety flax placed on suitable agar media. A normal parasitic relationship was established within 4 weeks, as shown by the presence of numerous haustoria. The rust mycelium invaded intercellular spaces in the cotyledons as well as in well-established adventitious roots. Uredosori formed mainly on thickened parts of the cotyledons, adjacent to callus tissue. Nuclei in uredospores were difficult to observe but in general there seemed to be two per spore. Teliosori formed infrequently under the conditions used but in some cultures they did develop on the cotyledons and on the oldest parts of adventitious roots. Teliospores were uninucleate.
Qualitative histochemistry of the shoot apex of Triticum
Authors: Evans Lance S. , Berg Arthur R.
Published: March 2008

Qualitative histochemical assays localized lipids, carbohydrates, succinate dehydrogenase, and acid phosphatase in Triticum aestivum seedlings. Starch was present in the base of the shoot apex and near vascular tissues throughout the seedlings. Succinate dehydrogenase activity was located in the apical summit, apical base, young leaf primordia, and very young axillary buds. Acid phosphatase was localized at the base of the apex, scutellum, and aleurone tissues. Thicker cell walls were noted in the epidermis of the apical dome and at the base of the apex. This combination of histochemical staining patterns suggests initiation of provascular tissue very early in leaf initiation.
Boron autoradiography of botanical specimens
Authors: Stinson Robert H.
Published: March 2008

Boron autoradiographs of plant material may be obtained on a new commercially available "film." Samples and film are placed in a neutron source. The film records the location of boron atoms by detecting alpha particles emitted from boron after neutron capture. The film is completely insensitive to gamma rays, which usually cause undesirable darkening when this technique is used with conventional photographic film. Variation in content of boron in sunflowers grown at varying boron concentrations was easily detected. Boron tends to accumulate at the tip and along the margins of the leaf.
Adjustment for gas exchange threshold enhances precision of heart rate-derived VO2 estimates during heavy exercise
Authors: Pettitt Robert W. , Symons J. David , Taylor Julie E. , Eisenman Patricia A. , White Andrea T.
Published: March 2008

Overestimates of oxygen uptake (VO2) are derived from the heart rate reserve – VO2 reserve (HRR–VO2R) model. We tested the hypothesis that adjusting for differences above and below gas exchange threshold (HRR–GET model) would tighten the precision of HR-derived VO2 estimates during heavy exercise. Seven men and 7 women of various VO2 max levels, on 2 separate days, cycled for 6 min at intensities equal to power at GET, 15% the difference between GET and VO2 max (15% above), and at 30% above GET. A second bout at 15% above GET (15% above (bout 2)) after 3 min of recovery was performed to assess estimates during interval training. Actual VO2 was compared with estimates derived from the HRR–VO2R and the HRR–GET. VO2 values were summed over the 6 min duration of data collection (6 min LO2) and compared with Bland–Altman plots. HRR–VO2R yielded 6 min LO2 (±2 SD) overestimates of 2.0 (±2.5), 1.9 (±2.7), and 1.3 (±3.3) for GET, 15% over, and 30% over, respectively, whereas corresponding 6 min LO2 difference values for the HRR–GET model were –0.42 (±1.6), –0.23 (±1.1), and –0.55 (±1.8), respectively. For 15% above (bout 2), the 6 min LO2 difference for HRR–VO2R was 1.8 (±2.9), whereas the difference for HRR–GET was 0.17 (±1.4). The 6 min LO2 values relative to the subjects’ VO2 max did not vary (r = 0.05 to 0.36); therefore, fitness level did not affect estimates. Sex did not affect accuracy of either estimate model (sex X estimate model interaction, p > 0.95). We observed accurate estimates from the HRR–GET model during heavy exercise.
Are functional foods redefining nutritional requirements?
Authors: Jones Peter J. , Varady Krista A.
Published: March 2008

Functional foods are increasing in popularity owing to their ability to confer health and physiological benefits. Nevertheless, the notion that functional foods improve health when providing nutrients at levels above and beyond existing recommended intakes is inconsistent with the definition of requirement. This disparity highlights the need for an alternative definition of nutrient requirement. The present objective is to examine distinctions between optimization of health, as defined by what we currently deem as required intakes, versus adding physiological benefit using bioactive agents found in functional foods. Presently, requirement is defined as the lowest amount of intake of a nutrient that will maintain a defined level of nourishment for a specific indicator of adequacy. In contrast, functional foods are described as ingredients that are not necessary for body function, yet provide added physiological benefit that confer better overall health. Plant sterols are one example of such an ingredient. Plant sterols lower plasma cholesterol concentrations, and may thus be considered essential nutrients in physiological situations where circulating cholesterol concentrations are high. Similarly, intakes of omega-3 fats beyond existing requirement may confer additional health benefits such as hypolipidemic and anti-diabetic effects. These examples underscore the inconsistencies between what is defined as a nutrient requirement versus what is identified as a health benefit of a functional food. Such discrepancies emphasize the need for a more all-encompassing definition of a nutrient requirement; that is, one that moves beyond the prevention of overt deficiency to encompass improved health and disease risk reduction.
Increase in depression symptoms with weight loss: association with glucose homeostasis and thyroid function
Authors: Chaput Jean-Philippe , Arguin Hélène , Gagnon Claudia , Tremblay Angelo
Published: March 2008

The purpose of this study was to assess the potential impact of weight loss up to a state of plateau on symptoms of depression. Eleven obese men (mean body mass index (BMI) = 33.4 kg·m–2, mean age = 38 y) participated in this repeated-measures, within-subjects, clinical intervention. They were subjected to a weight-loss program that consisted of a supervised diet and exercise clinical intervention. The phases investigated were (i) baseline; (ii) after 5 ± 1 kg loss of body mass (phase 1); (iii) after 10 ± 1 kg weight loss (phase 2); and (iv) at resistance to further weight loss (plateau). At each phase of the weight-reducing program, glucose homeostasis markers were determined using an oral glucose tolerance test (OGTT). Serum thyroid-stimulating hormone (TSH), total triiodothyronine (T3), and free thyroxine (fT4) concentrations were also measured and the Beck Depression Inventory (BDI) was administered. The weight loss plateau occurred after 7.4 ± 1.9 months of intervention and corresponded to a loss of 11.2% of initial body weight (93.9% of which was from fat stores). This amount of weight loss induced a significant decrease in resting metabolic rate (RMR) (p < 0.05) and a significant increase in desire to eat (p < 0.05) and in depression symptoms (p < 0.01) compared with baseline. Intriguingly, the glucose area below fasting values (GABF) at plateau was significantly higher as compared with other phases of the program (p < 0.01). We found a strong negative correlation (r = –0.77, p < 0.01) between the change in glucose concentrations at 180 min of the OGTT and the change in BDI scores between plateau and baseline values. Similarly, highly significant relationships were found between the change in T3 or fT4 concentrations and the change in BDI scores (r = –0.71 and r = –0.68, respectively; p < 0.01). Weight loss until plateauing is associated with a trend toward hypoglycemia at the end of the oral glucose challenge and with a decrease in T3 and fT4 levels. These physiological changes are shown to be highly linked with the increase in depression symptoms observed at plateau. Taken together, these data emphasize the relevance of caution and reasonable objectives when prescribing a weight reduction program to obese individuals.
Effect of estrogenic compounds (estrogen or phytoestrogens) combined with exercise on bone and muscle mass in older individuals
Authors: Chilibeck Philip D. , Cornish Stephen M.
Published: March 2008

Exercise has a beneficial effect on bone, possibly by stimulating estrogen receptor α. Because estrogen up-regulates this receptor, estrogen therapy combined with exercise training may be optimal for increasing bone mineral density. Studies combining estrogen therapy and exercise training in postmenopausal women show mixed results, but indicate that the combination of interventions may be more effective for increasing bone mass than either intervention alone. Plant-like estrogens (i.e phytoestrogens such as soy isoflavones) may act as weak estrogen agonists or antagonists, have small beneficial effects on bone, and may interact with exercise for increasing bone mineral density. Phytoestrogen derived from flaxseed (flax lignans) has not been evaluated as extensively as soy isoflavones and thus its effect on bone is difficult to determine. Estrogen or soy isoflavones given to postmenopausal women results in a small increase in lean tissue mass that may be mediated through estrogen receptor α on muscle or through decreased inflammation.
Impact of metformin on peak aerobic capacity
Authors: Braun Barry , Eze Pamela , Stephens Brooke R. , Hagobian Todd A. , Sharoff Carrie G. , Chipkin Stuart R. , Goldstein Benjamin
Published: March 2008

Individually, exercise and the drug metformin have been shown to prevent or delay type 2 diabetes. Metformin mildly inhibits complex I of the electron transport system and may impact aerobic capacity in people exercising while taking metformin. The purpose of the study was to evaluate the effects of metformin on maximal aerobic capacity in healthy individuals without mitochondrial dysfunction. Seventeen healthy, normal-weight men (n = 11) and women (n = 6) participated in a double-blind, placebo-controlled, cross-over design. Peak aerobic capacity was measured twice using a continuous, incrementally graded protocol; once after 7–9 d of metformin (final dose = 2000 mg/d) and once with placebo, with 1 week between tests. The order of the conditions was counterbalanced. Peak oxygen uptake (VO2 peak), heart rate (HR), ventilation (VE), respiratory exchange ratio (RER), rating of perceived exertion (RPE), and test duration were compared across conditions using paired t tests with the R statistical program. VO2 peak (–2.7%), peak heart rate (–2.0%), peak ventilation (–6.2%), peak RER (–3.0%), and exercise duration (–4.1%) were all reduced slightly, but significantly, with metformin (all p < 0.05). There was no effect of metformin on RPE or ventilatory breakpoint. Correlations between the decrement in VO2 peak and any of the other outcome variables were weak (r2 < 0.20) and not significant. Short-term treatment with metformin has statistically significant, but physiologically subtle, effects that reduce key outcomes related to maximal exercise capacity. Whether this small but consistent effect is manifested in people with insulin resistance or diabetes who already have some degree of mitochondrial dysfunction remains to be determined.
Introduction to proceedings from the 2005 CSEP symposium “Exercise and the endothelium”
Authors: Tschakovsky Michael E.
Published: March 2008

This introduction summarizes the topics addressed in the three companion review papers on various issues surrounding exercise and the endothelium. Leading experts in the field discuss the most recent findings regarding the following: (i) nitric oxide and exercise hyperemia, (ii) the response of the endothelium to exercise training, and (iii) the impact of exercise on the vascular biology of angiotensin as it relates to the vascular endothelium.
Vascular nitric oxide: effects of exercise training in animals
Authors: McAllister Richard M. , Newcomer Sean C. , Laughlin M. Harold
Published: March 2008

Exercise training is known to induce several adaptations in the cardiovascular system, one of which is increased skeletal muscle blood flow at maximal exercise. Improved muscle blood flow, in turn, could in part be accounted for by augmented endothelium-dependent, nitric oxide (NO)-mediated vasodilation. Studies have indeed demonstrated that endothelium-dependent, NO-mediated dilation of conductance-type vessels is augmented after endurance exercise training; recently, this adaptation has been extended into resistance-type vessels within rodent skeletal muscle. With the latter, however, it appears that only resistance vessels supplying muscle active during training sessions exhibit this adaptation. These findings in rats are in contrast to those from human studies, in which increased endothelium-dependent dilation has been observed in vasculatures not associated with elevated blood flow during exercise. Increased expression of endothelial NO synthase (eNOS) appears to underlie enhanced endothelium-dependent, NO-mediated dilation of both conductance and resistance vessels. Greater eNOS expression may also underlie the preventive and (or) rehabilitative effect(s) of exercise training on atherosclerosis, given that NO inhibits several steps of the atherosclerotic disease process. Thus, exercise training may induce adaptations that benefit both vasodilation and vascular health.
Nitric oxide and muscle blood flow in exercise
Authors: Tschakovsky Michael E. , Joyner Michael J.
Published: March 2008

Despite being the subject of investigation for well over 100 years, the nature of exercising muscle blood flow control remains, in many respects, poorly understood. In this review we focus on the potential role of nitric oxide in vasodilation of muscle resistance vessels during a bout of exercise. Its contribution is explored in the context of whether it contributes to steady-state exercise hyperemia, the dynamic adjustment of muscle blood flow to exercise, or the modulation of sympathetic vasoconstriction in exercising muscle. It appears that the obligatory role of nitric oxide in all three of these categories is modest at best. The elucidation of the integrated nature of exercise hyperemia control in terms of synergy and redundancy of mechanism interaction remains in its infancy, and much more remains to be learned about the role of nitric oxide in this type of integrated control.
Muscling in on microarrays
Authors: Virtanen Carl , Takahashi Mark
Published: March 2008

Adaptations that are the result of exercise require a multitude of changes at the level of gene expression. The mechanisms involved in regulating these changes are many, and can occur at various points in the pathways that affect gene expression. The completion of the human genome sequence, along with the genomes of related species, has provided an enormous amount of information to help dissect and understand these pathways. High-throughput methods, such as DNA microarrays, were the first on the scene to take advantage of this wealth of information. A new generation of microarrays has now taken the next step in revealing the mechanisms controlling gene expression. Analysis of the regulation of gene expression can now be profiled in a high-throughput fashion. However, the application of this technology has yet to be fully realized in the exercise physiology community. This review will highlight some of the latest advances in microarrays and briefly discuss some potential applications to the field of exercise physiology.
Home parenteral nutrition in advanced cancer: where are we?
Authors: Mackenzie Michelle L. , Gramlich Leah
Published: March 2008

Patients with advanced and incurable cancer are a compelling group. Questions and comments that these individuals and their families have may include: “My daughter is expecting our first grandchild in 3 months — can I hope to see our new family member?”; “I can’t keep any food down — is there anything I can do?”; “I am worried about losing so much weight, and feeling tired and weak — is there anything that may help?”; “Will I suffer a lot?”. Indeed, the most pressing concerns of the patient relate to predictions about survival and control of symptoms. The clinician taking care of the patient may wonder what is the utility or futility of home parenteral nutrition (HPN) in both the individual with advanced cancer and in this population of patients at large, whether there is potential for harm such as increasing the burden of care or prolonging suffering, and how to optimize care and communication with the patient and their families. The nutrition scientist may want to know what the implications of advanced cancer are on nutrient requirements and utilization, whether there are markers that would differentiate between cachexia and simple starvation, and whether it is possible to use specific nutrients to modify the disease process. This review will provide insights into the understanding of the role of HPN in advanced cancer and opportunities for further investigation.
Influence of exercise intensity on pulmonary oxygen uptake kinetics at the onset of exercise and recovery in male adolescents
Authors: Lai Nicola , Nasca Melita M. , Silva Marco A. , Silva Fatima T. , Whipp Brian J. , Cabrera Marco E.
Published: March 2008

The dynamics of the pulmonary oxygen uptake (VO2) responses to square-wave changes in work rate can provide insight into bioenergetic processes sustaining and limiting exercise performance. The dynamic responses at the onset of exercise and during recovery have been investigated systematically and are well characterized at all intensities in adults; however, they have not been investigated completely in adolescents. We investigated whether adolescents display a slow component in their VO2 on- and off-kinetic responses to heavy- and very heavy-intensity exercise, as demonstrated in adults. Healthy African American male adolescents (n = 9, 14–17 years old) performed square-wave transitions on a cycle ergometer (from and to a baseline work rate of 20 W) to work rates of moderate (M), heavy (H), and very heavy (VH) intensity. In all subjects, the VO2 on-kinetics were best described with a single exponential at moderate intensity (τ1, on = 36 ± 11 s) and a double exponential at heavy (τ1, on = 29 ± 9 s; τ2, on = 197 ± 92 s) and very heavy (τ1, on = 36 ± 9 s; τ2, on = 302 ± 14 s) intensities. In contrast, the VO2 off-kinetics were best described with a single exponential at moderate (τ1, off = 48 ± 9 s) and heavy (τ1, off = 53 ± 7 s) intensities and a double exponential at very heavy (τ1, off = 51 ± 3 s; τ2, off = 471 ± 54 s) intensity. In summary, adolescents consistently displayed a slow component during heavy exercise (on- but not off- transition) and very heavy exercise (on- and off-transitions). Although the overall response dynamics in adolescents were similar to those previously observed in adults, their specific characterizations were different, particularly the lack of symmetry between the on- and off-responses.
Infection of red spruce, black spruce, and balsam fir seedlings with tomato mosaic virus
Authors: Jacobi Volker , Castello John D.
Published: March 2008

Red spruce (Picearubens Sarg.), black spruce (Piceamariana (Mill.) B.S.P.), and balsam fir (Abiesbalsamea (L.) Mill.) seedlings were root inoculated with tomato mosaic virus, potted, and maintained in a cold frame. The virus was detected by enzyme-linked immunosorbent assay in root extracts of several inoculated seedlings of each species 6–12 months postinoculation, and in root extracts of approximately 35–40% of both inoculated and noninoculated seedlings of each species 12–18 months postinoculation. Virus spread apparently occurred from the roots of infected to noninfected seedlings within the cold frame. The presence of virus in root extracts was confirmed by immunoelectron microscopy. The virus was not detected in the needles of any seedling at any time by either enzyme-linked immunosorbent assay or immunoelectron microscopy. A transitory needle chlorosis was observed in approximately 14% of the inoculated black spruce and 30% of the inoculated red spruce seedlings, but tomato mosaic virus was not detected in all plants with symptoms.
Effect of verbenone enantiomers and racemic endo-brevicomin on response of Dendroctonusfrontalis (Coleoptera: Scolytidae) to attractant-baited traps
Authors: Salom S. M. , Billings R. F. , Upton W. W. , Dalusky M. J. , Grosman D. M. , Payne T. L. , Berisford C. W. , Shaver T. N.
Published: March 2008

Different enantiomeric ratios and elution rates of the inhibitor pheromones verbenone and racemic endo-brevicomin were evaluated for their effects on the numerical response of the southern pine beetle, Dendroctonusfrontalis Zimm., to attractant-baited traps. Enantiomeric ratios and elution rates of verbenone were important factors in inhibiting response of male D. frontalis. Deterrence was most effective for enantiomeric ratios of verbenone containing 34 and 50% of the (+) enantiomer. Using a 34% (+): 66% (−) mixture of verbenone, the number of male D. frontalis captured in attractant-baited traps declined as elution rates increased from 4.2 to 12.5 mg/h. None of the enantiomeric ratios or elution rates of verbenone tested consistently influenced female response. endo-Brevicomin added to attractant-baited traps reduced catches of male D. frontalis, but did not significantly reduce catches further when added to traps also emitting verbenone. Female catches were not reduced significantly by the presence of endo-brevicomin. Numerical responses of the predatory beetle Thanasimusdubius Fab. are generally unaffected by the presence of verbenone alone or in combination with endo-brevicomin.
Evaluating peat as a growing medium for jack pine seedlings. 1. Conventional quality indices
Authors: Folk R. S. , Timmer V. R. , Scarratt J. B.
Published: March 2008

Jack pine (Pinusbanksiana Lamb.) seedlings were grown in paperpots filled with 26 different horticultural peat moss substrates to evaluate conventional laboratory indices for characterizing container growing media. Seedling growth performance varied on the different substrates; dry weight differed 52% and height at harvest differed 37% between the best and poorest yielding peat. Precultural physical and chemical properties of the growing media varied widely, but correlated weakly with growth and nutrient composition of the seedlings, suggesting that conventional laboratory indices were not sensitive enough to predict peat suitability for jack pine culture. Height growth was significantly related to nutrient composition of the seedlings; however, correlations were low when tested against initial measures of peat nutrient status. Foliar vector diagnoses of both high- and low-yield plants identified N and P as the primary and secondary nutritional constraints upon growth, respectively. Since plants received a common fertilizer regime, seedling development may be more closely associated with specific fertilizer–substrate interactions rather than conventional precultural test measures. Further research is needed to develop quality indices more sensitive to potential nutrient supply and fertilizer reactions in container rooting media.
Influence of soil drainage on early development and biomass production of young, herbicide-released fir–spruce stands in north central Maine
Authors: Meng X. , Seymour R. S.
Published: March 2008

The hypothesis that soil drainage affects early development of managed balsam fir–red spruce (Abiesbalsamea (L.) Mill.–Picearubens Sarg.) stands was examined by comparing age structures, growth rates of dominant trees, and above-ground biomass production (by components) between well drained and poorly drained soils on the Chesuncook catena. Nearly all dominant trees of both fir and spruce originated between 1974 and 1977 as advance seedlings that averaged 6–8 years old at overstory removal and required an average of 4–5 years to reach breast height afterward. Older advance seedlings reached breast height sooner; neither age at overstory removal nor time to breast height were related to drainage. After trees reached breast height, growth in height and basal diameter was significantly greater on well drained soils for fir, but not for red spruce. As a result, total biomass production was greater on well drained soils (15.1 Mg/ha) than on poorly drained soils (9.4 Mg/ha), although biomass varied widely owing to irregular stocking. Biomass data are combined with other studies of Abies spp. in a chronosequence to examine leading hypotheses of foliar and total biomass accumulation over time.
Litter spider succession after clear-cutting in a western coniferous forest
Authors: McIver J. D. , Parsons G. L. , Moldenke A. R.
Published: March 2008

The litter spiders of a coniferous forest in western Oregon were trapped in pitfalls to study the effects of, and recovery after, clear-cutting. Traps were placed in old-growth sites (150–450 years) and in clearcuts of three different ages (4–7, 16–19, and 22–31 years); each age-class was represented by sites that differed along a gradient of moisture availability. A total of 8905 individuals were collected over the 2-year study period, comprising 93 species, 54 genera, and 15 families. Visual pursuit hunting spiders dominated clearcuts, while "sit and wait" microweb and trapdoor spiders dominated mature forests. Most of the common forest species were reestablished in the wettest sites by 30 years after clear-cutting; species composition in dry 30-year-old clearcuts more closely resembled the fauna of shrubby wet 16-year-old clearcuts. Microenvironmental conditions and the availability and species composition of prey are the most likely factors behind variation in spider species composition among sites. Prey and microenvironment are in turn largely influenced by canopy closure and litter depth. The use of litter spiders as bioindicators of litter habitat quality and forest recovery is discussed.
Marker-aided selection in a backcross breeding program for resistance to chestnut blight in the American chestnut
Authors: Bernatzky Robert , Mulcahy David L.
Published: March 2008

Marker-assisted selection in backcross breeding is discussed in general and with specific reference to obtaining resistance to chestnut blight in American chestnut (Castaneadentata (Marsh.) Borkh.). Resistance from Chinese chestnut (Castaneamollissima Blume) is thought to be controlled by two unlinked codominant genes. Hybrids and backcross generations are available that would allow (i) the identification of DNA markers that linked to the resistance and (ii) the development of a genetic linkage map for the genome. These markers are codominant. Markers that are linked to the resistance genes would permit detection of the different genetic classes of resistance that may have similar phenotypes. Linked markers also provide the ability to identify individuals with a maximum amount of recombination surrounding the resistance loci thereby eliminating unwanted linked donor genetic material. Having molecular markers scattered throughout the genome would allow general selection against the background donor genome. This can reduce the number of backcross generations required to obtain individuals with the phenotype of C. dentata but with the blight resistance of C. mollissima. Methods are presented for the development of a set of random genomic markers.
Potential applications of molecular markers for genetic analysis of host–pathogen systems in forest trees
Authors: Nance Warren L. , Tuskan Gerald A. , Nelson C. Dana , Doudrick Robert L.
Published: March 2008

Applications of molecular markers for genetic analysis of host–pathogen systems are presented within the framework of the gene-for-gene model. The literature on complementary genetic interactions in host–pathogen systems is briefly reviewed. Flor's gene-for-gene hypothesis is summarized, and the design, execution, and genetic interpretation of experiments to test this hypothesis are described in detail. Various molecular techniques that have been used to complement the traditional gene-for-gene approach are also briefly reviewed. Three alternative approaches to developing molecular markers using the gene-for-gene framework are presented to illustrate the potential for applying molecular markers in forest tree–pathogen systems. Two of these alternative approaches allow partial confirmation of a hypothesized gene-for-gene genetic model without the usual requirement for advanced pedigrees. Such alternative approaches could greatly accelerate the development of marker-aided selection for disease resistance in forest tree–pathogen systems.
MONTE CARLO METHODS IN FUZZY NON-LINEAR REGRESSION
Authors: ABDALLA AREEG , BUCKLEY JAMES
Published: March 2008

We apply our new fuzzy Monte Carlo method to certain fuzzy non-linear regression problems to estimate the best solution. The best solution is a vector of triangular fuzzy numbers, for the fuzzy coefficients in the model, which minimizes an error measure. We use a quasi-random number generator to produce random sequences of these fuzzy vectors which uniformly fill the search space. We consider example problems to show that this Monte Carlo method obtains solutions comparable to those obtained by an evolutionary algorithm.
FUZZY SIMILARITY AND MEASURE OF SIMILARITY WITH LUKASIEWICZ IMPLICATOR
Authors: BEG ISMAT , ASHRAF SAMINA
Published: March 2008

Given a universe of discourse X. A fuzzy similarity mapping ST,Inc : F(X) × F(X) → F(X) is defined, where F(X) denotes the set of all fuzzy subsets of X. Mapping ST,Inc maps two fuzzy sets A and B to a fuzzy set ST,Inc(A,B) in X called their fuzzy set of similarity. A measure of similarity between A and B is then obtained by applying the composite of fuzzy measure and fuzzy similarity mapping on the pair (A,B). Several properties of fuzzy set of similarity and the measure of fuzzy similarity are obtained within the framework of Lukasiewicz fuzzy implicator and its respective t-norm and t-conorm. Many examples of measure of similarity are also constructed.
PRICING STOCK OPTIONS USING BLACK-SCHOLES AND FUZZY SETS
Authors: BUCKLEY JAMES J. , ESLAMI ESFANDIAR
Published: March 2008

We use the basic Black-Scholes equation for pricing European stock options but we allow some of the parameters in the model to be uncertain and we model this uncertainty using fuzzy numbers. We compute the fuzzy number for the call value of option with and without uncertain dividends. This fuzzy set displays the uncertainty in the option's value due to the uncertainty in the input values to the model. We also correct an error in a recent paper which also fuzzified the Black-Scholes equation.
GP VERSUS GLS SPATIAL INDEX MODELS TO FORECAST SINGLE-FAMILY HOME PRICES
Authors: KABOUDAN MAK
Published: March 2008

This paper investigates use of genetic programming regression models to forecast home values. Neighborhood prices in a city are represented by a quarterly index. Index values are ratios of each local neighborhood to the global city average real price of homes sold. Relative average neighborhood home attributes, local socioeconomic characteristics, spatial measures, and real mortgage rates explain spatiotemporal variations in the index. To examine efficacy of model estimation, forecasts obtained using genetic programming are compared with those obtained using generalized least squares. Out-of-sample genetic programming predictions of home prices obtained using spatial index models deliver reasonable forecasts of home prices.
Topoisomerase IIα Expression as an Independent Prognostic Factor in Hodgkin's Lymphoma
Authors: Doussis-Anagnostopoulou Ipatia A. , Vassilakopoulos Theodoros P. , Thymara Irini , Korkolopoulou Penelope , Angelopoulou Maria K. , Siakantaris Marina P. , Kokoris Styliani I. , Dimitriadou Evangelia M. , Kalpadakis Christina , Matzouranis Marina , Kaklamanis Loukas , Panayiotidis Panayiotis , Kyrtsonis Marie-Christine , Androulaki Athina , Patsouris Efstratios , Kittas Christos , Pangalis Gerassimos A.
Published: March 2008

Purpose: To correlate the immunohistochemical expression of topoisomerase IIα (topoIIα) in Hodgkin's lymphoma (HL) with clinicopathological parameters, the expression of Ki-67 and the outcome of patients, who had been homogenously treated with ABVD or equivalent regimens.

Experimental Design: Immunohistochemistry using the monoclonal antibody Ki-S1 (topoIIα) was performed in 238 HL patients. MiB1 (Ki-67) expression was evaluated in 211/238.

Results: The mean ± SD percentage of topoIIα- and Ki-67–positive Hodgkin-Reed-Sternberg (HRS) cells was 63 ± 19% (5%-98%) and 73 ± 19% (8%-99%), respectively. The median percentage of topoIIα-positive HRS cells was 64% (interquartile range, 51-78%). There was no correlation between topoIIα expression and patient characteristics. TopoIIα and Ki-67 expression were correlated (Spearman's Rho 0.255, P < 0.001). TopoIlα expression within the highest quartile of this patient population was predictive of failure free survival (FFS) (10-year rates 82 ± 3% vs 68 ± 7%, P = 0.02 for patients falling into the quartiles 1-3 and 4 respectively). In multivariate analysis topoIIα expression was independently predictive of FFS.

Conclusion: TopoIIα was expressed in all cases of HL showing a correlation with Ki-67 expression. Under current standard therapy including drugs inhibiting its activity, topoIIα was an independent adverse predictor of FFS with no statistically significant correlation with other established prognostic factors.