bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared reflectivity and intrinsic dielectric behavior of RETiTaO6 (RE = Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb) microwave ceramics
Authors: Paschoal C.W.A. , Moreira R.L. , Surendran K.P. , Sebastian M.T.
Published: May 2005

In this work, we performed infrared reflectivity measurements of RETiTaO6 dielectric ceramics for rare-earth (RE) = Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb. The infrared spectra were analyzed through the four-parameter semi-quantum model based on two orthorhombic (aeschynite and euxenite) structures presented by the ceramics. We discerned the strongest phonon modes that contribute to the intrinsic dielectric behavior of the two families. Then the unloaded quality factors and the dielectric permittivities were estimated at the microwave region. The variations of the intrinsic dielectric response of both systems with RE ion substitution are discussed in terms of changes in their dielectric polarizabilities. It is proposed that the covalency of the RE–O bonds play an important role in the evolution of dielectric permittivity as well as in the sign of the temperature coefficient of the resonant frequency.
Heteroepitaxial growth and structural analysis of epitaxial α–Fe2O3(1010) on TiO2(001)
Authors: Williams Joshua R. , Wang Chongmin , Chambers Scott A.
Published: May 2005

We grew epitaxial α–Fe2O3(1010) on TiO2(001) rutile by oxygen plasma-assisted molecular-beam epitaxy. High-resolution transmission electron microscopy (HRTEM), reflection high-energy electron diffraction (RHEED), and x-ray diffraction pole figures confirm that the film is composed of four different in-plane orientations rotated by 90° relative to one another. For a given Fe2O3 unit cell, the lattice mismatch along the parallel [0001]Fe2O3 and [100]TiO2 directions is nominally +67%. However, due to a 3-fold repetition of the slightly distorted square symmetry of anion positions within the Fe2O3 unit cell, there is a coincidental anion alignment along the [0001]Fe2O3 and [100]TiO2 directions, which results in an effective lattice mismatch of only −0.02% along this direction. The lattice mismatch is nearly 10% in the orthogonal [1120]Fe2O3 and [100]TiO2 directions. The film is highly ordered and well registered to the substrate despite a large lattice mismatch in one direction. The film grows in registry with the substrate along the parallel [0001]Fe2O3 and [100]TiO2 directions and nucleates dislocations along the orthogonal [1120]Fe2O3 [100]TiO2 directions.
Raman-based analysis of implantation-induced expansion and stresses in sapphire crystals
Authors: Gurarie V.N. , Otsuka P.H. , Jamieson D.N. , Prawer S.
Published: May 2005

Raman spectroscopy was used to determine the lattice expansion and stress distribution within the ion implanted layer in sapphire crystals. The crystals with the (1120) facewere implanted with 3.0 MeV H+ ions to doses of 3.3 × 1017 cm−2 and 4.8 × 1017 cm−2.The strain components and their variation with depth were analyzed by measuring the shift of the Raman peak on the cross-sectional basal plane. A continuum mechanics approach considered a model of a semi-infinite anisotropic elastic space subjected to the implantation-induced lattice expansion. The expansion and resulting compressive stresses were found to increase with depth, reaching a sharp maximum at the end of the ion range. The implantation-induced expansion coefficient was shown to be independent of the ion energy loss and implantation depth in sapphire. Such behavior was discussed in light of stopping and range of ions in matter data and defect production by nuclear collisions and ionization processes.
Effect of pH on ceria–silica interactions during chemical mechanical polishing
Authors: Abiade Jeremiah T. , Choi Wonseop , Singh Rajiv K.
Published: May 2005

To understand the ceria–silica chemical mechanical polishing (CMP) mechanisms, we studied the effect of ceria slurry pH on silica removal and surface morphology. Also, in situ friction force measurements were conducted. After polishing; atomic force microscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy were used to quantify the extent of the particle–substrate interaction during CMP. Our results indicate the silica removal by ceria slurries is strongly pH dependent, with the maximum occurring near the isoelectric point of the ceria slurry.
Microstructures and material properties of fibrous Al2O3–(m-ZrO2)/t-ZrO2 composites fabricated by a fibrous monolithic process
Authors: Lee Byong-Taek , Kim Ki-Hyun , Han Jae-Kil
Published: May 2005

Al2O3–(m-ZrO2)/t-ZrO2 composite having fibrous and homogeneous microstructure was successfully fabricated using a fibrous monolithic process. The composites had a homogeneous microstructure as well as good interfaces between the Al2O3–(m-ZrO2) and t-ZrO2 phases. The thickness of each phases were reduced to 375, 50, 5 μm, and 0.7 μm as the number of extrusion passes increased up to 5. The material properties of density, hardness, bending strength, and fracture toughness increased as the passes of extrusion were increased up to a fifth pass, and their maximum values were about 98.5%, 1230 Hv, 570 MPa, and 6.5 MPa⋅m1/2, respectively. The fracture toughnesses in the direction of longitudinal and transverse direction of the fifth passed sample showed the different values with about 6.5 and 5.4 MPa⋅m1/2, respectively.
Environmental factors affecting sporulation of Fuligo septica (Myxomycetes) on sugar cane bagasse
Authors: Chiappeta Alda de Andrade , Sena Kêsia Xisto Fonseca R. de , Cavalcanti Laise de Holanda
Published: May 2005

The influence of environmental factors on sporulation of Fuligo septica (L.) Wigg. and the abundance of this species on sugar cane bagasse (Saccharum officinarum L.), stored outdoors was studied.In Northeastern Brazil, between January/1997 and January/1998, a total of 29 specimens were collected through monthly collections of aethalia. The relationships between the abundance of aethalia and rainfall, temperature, relative humidity of the air and insolation were studied. Results indicated that on the substrate analyzed, F. septica was an abundant species. Sporulation occurred in all seasons of the year, with a well-defined peak at the end of winter and beginning of spring (August/September),which was strongly influenced by rainfall.
Characterization of Nomuraea rileyi strains using polymorphic DNA, virulence and enzyme activity
Authors: Vargas Lúcia Rosane Bertholdo , Rossato Marcelo , Ribeiro Rute Terezinha da Silva , Barros Neiva Monteiro de
Published: May 2005

The characterization of entomopathogenic microorganisms is important for the selection of more effective strains for use in integrated pest-control programs. Five Nomuraea rileyi strains (SA86101, GU87401, SR86151, CG128 and VA9101) were characterized using random amplified polymorphic DNA (RAPD) analysis, virulence studies and assessment of chitinolytic and proteolytic activity. RAPD analysis divided the strains into two groups with a similarity coefficient of 0,76%, group 1 consisting of strains SA86101, GU87401 and SR86151 and group 2 of strains CG128 and VA9101. The LT50 varied from 165h with strain VA9101 to 246h with strain GU87401. Chitinolytic and proteolytic activity of the fungi after 144h growth in minimal medium were tested using colloidal chitin as substrate. All strains exhibited enzyme activity, with strain VA9101 having the highest chitinase activity (0,0040 mumol/mL/min the 40ºC) and strain SA86101 the highest proteolytic activity. No relationship was found between RAPD analysis, virulence and chitinase or protease activity.
Reaction of wheat genotypes to soil aluminum differential saturations
Authors: Costa Antonio , Campos Luís Alberto Cogrossi , Riede Carlos Roberto
Published: May 2005

Ten wheat (Triticum aestivum) genotypes were evaluated in microplots with aluminum saturation of 0, 15, 30 and 45%, during 1994, in Londrina, Paraná, Brazil. The soil was a Distrofic Red Latosol (Typic Haplorthox), with 65% saturation of aluminum, amended with dolomitic lime. Variables evaluated included grain yield and yield components: ears.m-2, grains.ear-1 and the weight of 1000 grains. Genotypes differed in yield and yield components. Increasing aluminum saturation decreased yield, ears.m-2 and grains.ear-1, but did not alter thousand kernel weight. The genotypes reacted differently in relation to the toxic soil aluminum. Anahuac and IAPAR 29 were aluminum sensitive; OCEPAR 16, Trigo BR 18, and Trigo BR 23 were moderately sensitive; IAPAR 6, IAPAR 53, and IAPAR 60 were moderately tolerant; while IAC 5-Maringá and Trigo BR 35 were tolerant.
Temperature effects on Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis
Authors: Maceda Arlei , Hohmann Celso L , Santos Honório R. dos
Published: May 2005

The influence of temperature on lifetime attributes of Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis (Hymenoptera: Trichogrammatidae) was evaluated at four constant temperatures (15, 20, 25, and 30º C), RH 70 ± 10%, photophase 14 h. Anagasta kuehniella (Lepidoptera: Pyralidae) eggs were used as hosts. Developmental times of both parasitoid species were similar when exposed to 20, 25, or 30º C. T. annulata, however, developed slightly faster than T. pretiosum at 15º C. Emergence rates of both species were above 89%. The temperature threshold for T. pretiosum and T. annulata was 11º C and the number of degree-days required for their development was 126.9 and 122.3, respectively. Parasitization was maximal at 25º C. T. annulata, however, parasitized significantly more hosts than T. pretiosum in the entire temperature range. Temperature had no effect in brood size.T. annulata progeny consisted predominantly of males, except at 15º C, whereas in T.pretiosumitconsisted predominantly of females, except at 30º C. Parental females lived longer than males.
Population dynamics, gregarious behavior and oviposition preference of Neomegalotomus parvus (Westwood) (Hemiptera: Heteroptera: Alydidae)
Authors: Ventura Maurício Ursi , Panizzi Antônio Ricardo
Published: May 2005

Interactions between Neomegalotomus parvus (Westwood) (Coreoidea: Heteroptera: Alydidae) and host plants were investigated including population monitoring throughout the year, gregarious behavior in the field, and oviposition preference among host plants and one non-host plant in field cages. Cowpea, Vigna unguiculata (L.) Walp., soybean, Glycine max (L.) Mill. cv. BR 37, pigeon pea, Cajanus cajan (L.) Mill., pigeon pea cv. Anão, and lablab, Dolichos lablab L. were monitored in the field. N. parvus was found on host plants during 11 months. The shortest period of occurrence was observed on soybean and the longest on lablab. Insects were found mostly on mature pods. Contagious distribution (negative bionomial) was detected, characterizing the aggregation. Greater number of eggs were observed on pigeon pea, followed by soybean and lablab. Eggs were not found on cowpea, on common bean Phaseolus vulgaris L., and on rice, Oryza sativa L.
Changes in the diet composition of transitory fishes in coastal systems, estuary and continental shelf
Authors: Chaves Paulo T. C. , Umbria Simone C.
Published: May 2005

The feeding habits of five species of teleosts in the southern coast of Brazil were analyzed comparatively between estuary and continental shelf. The displacement between the two sites caused expressive qualitative alterations, the proportion of different items varying from 50% in the diet of Micropogonias furnieri to 89% in Isopisthus parvipinnis. In the group of species, 57% of the items were exclusive to one of the environments and, within the three most common items in the estuary - fish, Polychaeta and plants, only the former was also among the most common items in the shelf. In spite of these differences, the high spectrum of items in both environments and the nature of the item that was most consumed in each one, indicate that there was a certain similarity of patterns between estuary and shelf: Chloroscombrus chrysurus had a carnivorous diet, with a predominance of copepods; M. furnieri and Menticirrhus americanus showed a tendency towards an omnivorous diet; and Cynoscion leiarchus and I. parvipinnis showed a tendency towards ichthyophagy.
Tabebuia avellanedae Lor. ex Griseb. (Bignoniaceae) submitted at the flooding and the "Ethrel" and silver nitrate application
Authors: Davanso Viviane M. , Medri Moacyr E. , Souza Luiz A. de , Colli Sandra
Published: May 2005

Three-month-old Tabebuia avellanedae Lor. ex Griseb. (Bignoniaceae) plants cultivated in the greenhouse were submitted to 56 days of flooding and to "Ethrel" and silver nitrate applications to find out it’s capacity for morphological and physiological modifications to survive under flooding conditions and at which degree such responses were correlated with alterations in the ethylene level. Flooding and the "Ethrel" application caused growth reduction and epinasty in T. avellanedae and the application of silver nitrate lessened some these symptoms. Certain symptoms shown during flooding by this species and its ability to develop structures which lessen hypoxia effects, such as stem fissures and hypertrophied lenticels in the roots, modifications which enable the species to adapt to short flooding periods, could be related to increases in the ethylene concentration in the plant tissues.
Microhabitat occupation by birds in a restinga fragment of Paraná coast, PR, Brazil
Authors: Pedroso Junior Nelson Novaes
Published: May 2005

Studies were carried out to characterize microhabitat occupation by birds in a restinga fragment of Paraná coast. Were described 14 microhabitats occupied in different manners for 64 species of birds. Based on the results, could be suggested that this conspicuous class of vertebrates, together with the other elements that integrate the restinga, serve as a component to attract and stimulate the interest for the comprehension and necessity of conservation by the visitors of such ecosystem.
Cysteine proteinases and cystatins
Authors: Oliveira Adeliana S. , Xavier-Filho José , Sales Maurício P.
Published: May 2005

This review describeds the definition, localization, functions and examples of cysteine proteinases and their protein inhibitors in vertebrate, non-vertebrate animals and plants. These inhibitors are related with defense mechanisms of plant against pests. It also describes the factors involved in the specific cysteine proteinase-cystatin interaction and high degree of affinity and large specificity in this interaction which are not only represented by the compatibility between amino acid residues of the active site involved in catalysis, but also of all amino acid residues that participante in the enzyme-inhibitor interaction.
Production of yeast extract from whey using Kluyveromyces marxianus
Authors: Revillion Jean P. de Palma , Brandelli Adriano , Ayub Marco A. Záchia
Published: May 2005

The yeast Kluyveromyces marxianus CBS 6556 was grown on whey to produce nucleotide-rich yeast extracts. Thermal treatments of cells at 35 or 50ºC for 15-30h resulted in yeast extracts containing about 20 g/L protein, with only the second treatment resulting in the presence of small amounts of RNA. In contrast, autolysis in buffered solution was the unique treatment that resulted in release of high amounts of intracellular RNA, being, therefore, the better procedure to produce 5'-nucletide rich extract with K. marxianus.
The effect of temperature, salinity and nitrogen products on food consumption of pink shrimp Farfantepenaeus paulensis
Authors: Wasielesky Jr. Wilson , Bianchini Adalto , Castaño Sanchez Cecilia. , Poersch Luis Henrique
Published: May 2005

Studies were carried out to investigate the effect of temperature, salinity, ammonia, nitrite and nitrate on food consumption of pink shrimp Farfantepenaeus paulensis. Juveniles (0.2 - 0.4 g) were acclimated for 15 days in seawater with different temperatures, salinities and concentrations of ammonia, nitrite and nitrate. After the acclimation period, 20 shrimps per treatment were individualized in order to have their ration intake analyzed through the amount of ration offered and left over within a 24-hour period. Mean food consumption presented significant alterations (P<0.05) for the tested temperatures and nitrite concentrations, whereas for the salinity, ammonia and nitrate treatments, shrimp presented no alteration on food intake (P>0.05). According to the results obtained, temperature and nitrite affected F. paulensis food consumption. On the other hand, variables as salinity, ammonia and nitrate did not affect shrimp appetite. However, the possibility of this to happen over long periods, prejudicing the species culture in captivity, reinforced the necessity of regular water quality management.
Intrusive Thoughts in Posttraumatic Stress Disorder
Authors: Falsetti Sherry A. , Monnier Jeannine , Davis Joanne L. , Resnick Heidi S.
Published: May 2005

This article reviews the literature on prevalence, associated features, assessment, and treatment of intrusive symptoms associated with posttraumatic stress disorder (PTSD). Research indicates that among trauma survivors, intrusive thoughts and imagery are quite common and distressing. It appears that early intrusions may be predictive of long-term distress and that avoidance and suppression can maintain intrusions. The treatment outcome literature for PTSD indicates that current cognitive behavioral treatments are effective in reducing intrusions. New data from a recent treatment outcome study for PTSD with comorbid panic attacks, using Multiple Channel Exposure Therapy, also suggest that this treatment is effective in significantly reducing intrusions.
Intrusive Thoughts in Depression
Authors: Wenzlaff Richard M.
Published: May 2005

This article traces the origins of intrusive thoughts in depression, devoting special attention to how misguided attempts to gain mental control can ironically fuel unwanted thoughts. A review of the research highlights the ways in which cognitive biases, stress, and thought suppression can contribute to the development and maintenance of depression. The article concludes with a consideration of the implications for treatment.
Trouble in Bed: The Role of Pre-Sleep Worry and Intrusions in the Maintenance of Insomnia
Authors: Harvey Allison G.
Published: May 2005

Insomnia chronically affects 1 in 9 individuals. It causes sufferers severe distress as well as social, interpersonal, and occupational impairment. One of the most replicated findings in the insomnia literature is that people who suffer from insomnia attribute their sleep disturbance to unwanted and excessive intrusive thoughts and worries whilst trying to get to sleep. This article aims to provide an overview of published studies relating to unwanted worry and intrusions in insomnia and to establish the extent to which unwanted worry and intrusions, and the management of them, contribute to the maintenance of insomnia. It is argued that a key mechanism underpinning excessive negatively toned cognitive activity is the strategy by which the unwanted thoughts are managed. Preliminary research is presented in support of this proposal and the clinical implications of it are discussed. It is concluded that investigations of the mechanisms underpinning excessive and unwanted pre-sleep intrusions and worry are in their infancy, but that it is a promising area for future research.
Decision Making and Personality Disorders
Authors: Leahy Robert L.
Published: May 2005

Individuals with different personality disorders are hypothesized to approach decision making with a variety of concerns related to their perception of their general efficacy, information demands, risk aversion, and utility of gains and losses. A variation of modern portfolio theory is employed to examine decision-making in a clinical population of adult patients. Variations along personality dimensions were related to a number of decision-making concerns and strategies. The implications of these findings are examined in the clinical treatment of personality disorders.
Predictors of Treatment Change and Engagement in Cognitive-Behavioral Group Therapy for Depression
Authors: Westra Henny A. , Dozois David J. A. , Boardman Christine
Published: May 2005

This study examined predictors of treatment response in 48 individuals who presented for participation in a 10-session cognitive-behavioral group therapy (CBGT) program for depression. The majority of participants carried a diagnosis of major depression and all were concurrently on at least 1 antidepressant medication. The therapeutic approach involved an integration of 2 empirically supported therapies: Beck’s cognitive therapy (Beck, Rush, Shaw, & Emery, 1979) and Lewinsohn’s Coping With Depression course (Lewinsohn, Antonuccio, Breckenridge, & Teri, 1984). Participants completed the Burns Depression Checklist, the Dysfunctional Attitudes Scale (DAS), and the Burns Hopelessness Scale, a 5-item questionnaire which assesses the degree of optimism/pessimism an individual has regarding mood and symptom control. No significant differences were found on pre-treatment dysfunctional attitudes or depressive symptomatology between individuals who dropped out of treatment (n = 9) and treatment completers (n = 39). However, pre-treatment hopelessness scores were significantly higher in dropouts than in individuals who completed treatment. Increased pessimism about symptom control was also related to fewer reductions in DAS scores throughout treatment among completers and to poorer overall treatment response. These findings suggest that negative expectations about treatment outcome may be associated with reduced treatment benefit in CBGT, and may place individuals at significantly greater risk of premature treatment termination. The theoretical and clinical significance of these findings are discussed and suggestions for future research and practice are detailed.
Talking Oneself Into Change: Motivational Interviewing, Stages of Change, and Therapeutic Process
Authors: Miller William R. , Rollnick Stephen
Published: May 2005

Motivational interviewing (MI) is a directive, person-centered clinical method for helping clients resolve ambivalence and move ahead with change. It can be applied as a preparation for treatment, a freestanding brief intervention, an enduring clinical style, or a fallback approach when motivational obstacles are encountered. A psycholinguistic theory is emerging to account for the efficacy of MI that has been demonstrated in numerous clinical trials. For cognitive therapists, MI provides an evidence-based alternative to direct disputation of client cognitions.
How Does Motivational Interviewing Work? What Client Talk Reveals
Authors: Amrhein Paul C.
Published: May 2005

A psycholinguistic account of motivational interviewing (MI) is proposed. Critical to this view is the assumption that therapists and clients are natural language users engaged in a constructive conversation that reveals and augments relevant information about the status of future change in a client’s substance abuse. The role of client speech acts—most notably, verbal commitments—during MI is highlighted. How commitments can be signaled in client speech or gestures is discussed. How these commitment signals can inform therapeutic process and subsequent behavioral outcome is then put forth. Using natural language as a measure, a MI process model is presented that not only posits a mediational role for client commitment in relating underlying factors of desire, ability (self-efficacy), need, and reasons to behavior, but also a pivotal role as a need-satisfying enabler of a social-cognitive mechanism for personal change.
Clinical Case Study: Clinical Use of the Looming Vulnerability Construct for Performance Anxiety in a Dance Recital
Authors: Riskind John H. , Long Daniel , Duckworth Rebecca , Gessner Ted
Published: May 2005

Several recent social phobia models (e.g., Clark & Wells, 1995; Rapee & Heimberg, 1997) share the assumption that sensitivity to the social evaluative context is produced by the socially anxious person’s generation of distorted mental images. These distorted images occur in the form of an external “observer” perspective in terms of how the person imagines being perceived by others. The starting point for the model of looming vulnerability (Riskind, 1997; Riskind, Williams, Gessner, Chrosniak, & Cortina, 2000) is that anxiety is generated not just by static images of such a dreadful moment caught in stop motion (e.g., of being negatively viewed by others), but by the perception that the threat is rapidly advancing and unfolding such that it is increasing in danger. The present case study illustrates the potential utility of this “looming vulnerability” conceptualization for treating a case of severe social performance anxiety in a young woman facing an upcoming dance recital.
Quantitative Genetic Analysis of the Physiological Processes underlying Maize Grain Yield
Authors: Lee E. A. , Ahmadzadeh A. , Tollenaar M.
Published: May 2005

Few studies have examined the inheritance and interrelationships of both grain yield and the underlying physiological processes in maize (Zea mays L.). The objective of this study was to establish genetic relationships between the physiological components of grain yield and to examine the inheritance of grain yield and its component processes (i.e., additive and the nonadditive genetic effects). Twelve F1 hybrids, obtained by mating three male and four female inbred lines using a North Carolina Design II, were evaluated in trials conducted in Ontario from 2000 to 2002. Dry matter accumulation (DMA) at four stages of development, harvest index, leaf area index (LAI), stay green, and grain yield were measured. Variation among the 12 hybrids was significant for all traits evaluated, and the range in mean grain yield was 28% of the mean. Using the genetic effects partitioned by a Design II analysis, we dissected the physiological mechanisms that influenced favorable or unfavorable contributions to grain yield. Using the highest‐ and lowest‐yielding hybrids in the study (i.e., maximum genetic variation), we attempted to dissect the physiological reasons for the difference in grain yield. This analysis, however, was unsuccessful in dissecting grain yield in terms of physiological mechanisms using a quantitative genetic model. Reasons for this failure may be, in part, (i) the relatively low contribution of statistically significant genetic effects to the differences between the hybrids; and (ii) partitioning of the difference between hybrids in four general combining ability (GCA) estimates and two specific combining ability (SCA) estimates results in small estimates relative to the grand mean.
Seed Maturity, Germination, and Endophyte Relationships in Tall Fescue
Authors: Hill N. S. , Bouton J. H. , Hiatt E. E. , Kittle B.
Published: May 2005

Endophytic fungi were once considered detrimental components of cool season pasture grass seed because of their association with toxic compounds. Development of new cultivars of forage grasses infected with nontoxic endophytes suggests endophytes are an essential component of pasture ecosystems. The process of transmitting endophytes via the seed embryo is poorly understood, and little is known about harvest conditions and endophyte transmission or viability. The objective of this project was to develop methods of predicting seed maturity and determine the effect of harvest maturity on viable endophyte transmission to seedling plants. Sixty panicles of tall fescue (Festuca arundinaceae Shreb.) from fields in Georgia and Oregon were sampled from 15 d after flowering until seed freely shattered (Georgia) or seed fields were swathed (Oregon). All fields had previously tested >90% infection with endophyte before the study. Panicles were staged for maturity by scoring for color of the panicle and seed, as well as seed shatter. Chlorophyll was extracted from a fresh subsample of seed, and dry matter was determined from a second subsample. Chlorophyll was estimated by measuring light absorbance at 540 nm. Seed with varying maturity scores were germinated following different prechill conditions. Regression of chlorophyll and dry matter content (dependent variables) with maturity score (independent variable) suggest chlorophyll content (r2 = 0.90) provided a better estimate of maturity than did dry matter (r2 = 0.55). The more mature seed had greater mass, germinated faster, had a higher total germination, and produced more vigorous seedlings. Endophyte transmission into the developing seed was similar within different maturity seed, but infection of seedlings increased from 81 to 91% with seed maturity. We conclude that predicting tall fescue seed maturity by chlorophyll analysis provides a better estimate for seed quality when maintaining endophyte viability is of concern in the harvested seed.
An Integrated Biplot Analysis System for Displaying, Interpreting, and Exploring Genotype × Environment Interaction
Authors: Yan Weikai , Tinker Nicholas A.
Published: May 2005

Multienvironment trials (MET) generate two types of two‐way data: genotype × environment data for a target trait and genotype × trait data in individual or across environments. These data can be visually analyzed by a GGE biplot and a genotype × trait biplot, respectively. This paper describes a third type of biplot, the covariate‐effect biplot, and illustrates its tandem use with the other biplots to achieve a fuller understanding of MET data. The covariate‐effect biplot is generated on the basis of an explanatory trait × environment two‐way table consisting of correlation coefficients between the target trait (e.g., yield) and each of the other traits in each of the environments. This biplot displays the yield‐trait relations in individual environments and addresses whether and how the genotype × environment interactions (GE) for yield can be explored by indirect selection for the other traits. These other traits are treated as genetic covariables and can be replaced by other genetic covariables such as genetic markers, QTL, or genes. The biplot methodology was demonstrated by MET data of barley (Hordeum vulgare L.) conducted across North America. Both the GGE biplot and the covariate‐effect biplot showed that the environments fell into two (eastern vs. western) megaenvironments. The covariate‐effect pattern explained 81% of the GGE pattern, suggesting that the GE pattern for yield can be effectively explored by indirect selection for these traits. Specifically, barley yield can be improved by selecting for larger kernel weight, earlier heading, and better lodging resistance in the eastern megaenvironment. In contrast, the yield–trait relationship in the western megaenvironment was highly variable, and yield improvement can be achieved only by selecting for yield per se across environments. We suggest that the GGE biplot, the genotype × trait biplot, and the covariate‐effect biplot be used jointly to better understand and more fully explore MET data.
Identification of Essentially Derived Varieties Obtained from Biparental Crosses of Homozygous Lines: I. Simple Sequence Repeat Data from Maize Inbreds
Authors: Heckenberger M. , Bohn M. , Melchinger A. E.
Published: May 2005

Genetic distances (GDs) based on molecular markers such as simple sequence repeats (SSRs) have been proposed as an appropriate tool to assess the genetic conformity between putative essentially derived varieties (EDVs) and their initial varieties (IVs). However, for maize (Zea mays L.) and other crops, no consensus has been reached regarding GD thresholds for identification of EDVs, mainly because reliable benchmark data are lacking. Our objectives were to (i) determine the variation in the parental contribution (p) to the genome of homozygous progeny lines derived in recycling breeding programs; (ii) investigate the power of SSR‐based GD estimates for discriminating between progeny lines derived from F2, BC1, and BC2 populations (BC = backcross); (iii) compare theoretical and simulated results of a companion study to our experimental data; and (iv) draw conclusions with regard to various EDV thresholds suggested hitherto. A total of 220 European and U.S. maize inbred lines comprising 163 triplets were genotyped with 100 uniformly distributed SSRs. A triplet consisted of one F2–, or BC1–derived progeny line and both parental lines. The SSR‐based estimates of p varied from 0.25 to 0.74 for F2–derived lines with a mean (0.49) close to the expectation (0.50), and ranged from 0.51 to 0.80 for BC1–derived lines with a mean (0.66) significantly smaller than the expectation (0.75). Relative to the variation in p, the GD between progeny lines and parents was little influenced by the variation in the GD between the parents, particularly for BC1–derived lines. Suggested GD thresholds for EDVs resulted in different Type I (α) and Type II (β) errors, depending on the germplasm pool. Considerable overlaps in the GD frequency distributions of F2–, BC1–, and BC2–derived lines indicate that the resolution to discriminate these types of progeny is poor unless a much larger number or a set of extremely polymorphic markers is used.
Selective Phenotyping to Accurately Map Quantitative Trait Loci
Authors: Jannink J.-L.
Published: May 2005

Recombination events are necessary to map QTL accurately and some progeny result from gametes with a greater number of recombination events than others. This observation suggests that some progeny should be more useful for QTL mapping than others. The marker genotypes of the progeny should allow the number of recombination events they carry to be determined such that the most useful progeny could be phenotyped, in a procedure termed selective phenotyping. Two methods to select genotypes for their usefulness in mapping are described, one that maximizes the overall mapping information content in the selected progeny, and one that seeks to maximize both overall mapping information and the uniformity of its distribution across the genome. Simulations showed that both methods successfully decreased the mean squared error (MSE) for QTL position. Average MSEs were similar for the two methods and variability of MSE was slightly lower for the latter relative to the former method. Simulations indicated that a large fraction of the decrease in the MSE achievable by selective phenotyping could be obtained by genotyping twice the number of progeny than were ultimately phenotyped, though further decreases in the MSE were observed when up to 16 times more progeny were genotyped than phenotyped. The procedure appears to most improve the accuracy of QTL mapping for QTL of small effect or when available markers do not allow marker spacing below 10 cM.
Agronomic Performance of Rht Alleles in a Spring Wheat Population across a Range of Moisture Levels
Authors: Butler Joshua D. , Byrne Patrick F. , Mohammadi Valiollah , Chapman Phillip L. , Haley Scott D.
Published: May 2005

Reduced height alleles at the Rht‐B1 and Rht‐D1 loci have been widely incorporated into wheat (Triticum aestivum L.) cultivars with the intent of improving partitioning of assimilates to grain. Although generally effective at increasing yield in high yield environments, their effects under heat and drought stress have been variable. We undertook this study to evaluate the effects of the Rht‐B1b and Rht‐D1b dwarfing alleles in a recombinant inbred line (RIL) spring wheat population under a range of soil moisture conditions. Rht‐B1 and Rht‐D1 genotypes of 140 RILs derived from a cross between ‘Kauz’ and MTRWA116 were determined by polymerase chain reactions (PCR). The population was evaluated for yield and agronomic traits in four Colorado environments under fully irrigated, partially irrigated, and rainfed conditions in 2001 and 2002. Lines with both dwarfing alleles were significantly (P < 0.01) shorter, lower yielding, and later heading in all environments compared with lines with one or no dwarfing allele. Lines with both tall alleles performed equal to or better (P < 0.05) than all other classes for grain yield, test weight, and kernel weight in all environments. Among lines with a single dwarfing allele, those with Rht‐B1b on average outyielded those with Rht‐D1b in the fully irrigated environment (5432 versus 4993 kg ha−1, P < 0.05), but elsewhere their yields did not differ (P > 0.05). Desirable values for most traits occurred across a relatively wide range of plant heights, with the best performing lines either shorter lines in the tall class or taller lines in the semidwarf classes.
Geographic Patterns of RAPD Variation in Cultivated Flax
Authors: Fu Yong-Bi
Published: May 2005

Geographic studies of plant molecular diversity can provide insights into plant domestication and enhance plant germplasm management and utilization, but such studies are lacking in cultivated flax (Linum usitatissimum L.). The objective of this study was to assess the geographic patterns of flax variability in a world collection of cultivated flax by random amplified polymorphic DNA (RAPD) markers. Sixteen RAPD primers were applied to screen 2727 flax accessions representing 63 countries and one group of unknown origin, and 149 RAPD bands were scored for each accession. Analyses of the RAPD data revealed a wide range of occurrence frequencies of polymorphic bands from 0.0004 to 0.9978 with an average of 0.537. The majority (84.2%) of the RAPD variation resided within accessions of each country and only 15.8% of the variation was present among accessions of different countries. Grouping the accessions into 12 major regions explained 8.2% of the RAPD variation. Accessions from the East Asia and European regions were most diverse, but accessions from the regions of Indian Subcontinent and Africa were most distinct. Accessions from the West Asia region were genetically more related to those from the Africa region and less to those from the Indian Subcontinent region. These findings are significant for understanding flax domestication and also are useful in classifying intraspecific diversity of cultivated flax, establishing a core subset of the flax collection, and exploring new sources of genes for flax improvement.
Diallel Analyses of Agronomic Traits Using Chinese and U.S. Maize Germplasm
Authors: Glover Max A. , Willmot David B. , Darrah Larry L. , Hibbard Bruce E. , Zhu Xiaoyang
Published: May 2005

Added genetic diversity among commercial maize (Zea mays L) hybrids may further increase yields and safeguard against vulnerability. Introducing exotic germplasm into breeding programs would increase the genetic base from which elite commercial inbreds are derived. Ten populations of maize, created from Chinese and/or U.S. inbreds or strains, were evaluated by Griffing's diallel analysis for combining ability of grain yield, stalk lodging, ear height, flowering time, and European corn borer (ECB; Ostrinia nubilalis Hübner) resistance to estimate their potential as sources of exotic germplasm for U.S. breeding programs. Grain yield general combining ability was largest for the population Mo17 Syn.(H14)C5, a synthetic improved by half‐sib selection using US13 as a tester. Grain yield specific combining ability was largest in the cross Chinese Mix 2 × Mo17 Syn.(H14)C5. Chinese Mix 2 × Mo17 Syn.(H14)C5 had more stalk lodging than the B73 × Mo17 and Pioneer Brand 3394 checks. Because of the high yield potential and other moderate‐to‐good agronomic traits of the cross combination, Chinese Mix 2 was selected as the best population for selection. Its large specific combining ability effect with Lancaster type material, which is commonly known in breeding programs, shows potential for further improvement. No native ECB resistance in Chinese germplasm was detected (two environments in 1 yr) compared with the resistant check Pioneer Brand 3184.
Selection for Water Use Efficiency Traits in a Cotton Breeding Program: Cultivar Differences
Authors: Stiller Warwick N. , Read John J. , Constable Gregory A. , Reid Peter E.
Published: May 2005

Water stress adversely affects both yield and fiber quality of cotton (Gossypium hirsutum L.) and any improvement in components of water use efficiency (WUE) would be expected to partially reduce these adverse affects. Six field experiments in Australia and one in Texas using four Australian and three Texas cultivars determined genetic differences in physiological WUE parameters. Four of the experiments were grown under dryland conditions and three under irrigated conditions. Cultivar differences for net photosynthesis (A) were found in only 30% of comparisons, ratio of intercellular CO2 concentration to ambient CO2 concentration (Ci/Ca) in 20%, and carbon isotope 13C discrimination (Δ) in 69%. Cultivars Cascot 014 and Sicot 189 had significantly (P ≤ 0.05) higher A than Siokra 1‐4 and Siokra L23 and these differences were consistent across experiments. A significant (P ≤ 0.05) cultivar × experiment interaction suggests Ci/Ca would be an environment specific measure enabling confident distinction of cultivar differences. Tamcot Sphinx and Cascot 014 had significantly higher Δ (P ≤ 0.001) than Siokra L23, with the ranking differing in only one irrigated experiment. Broad sense heritability estimates were 0.65, 0.68, and 0.56 for A, Δ, and lint yield, respectively. Cultivar variation for these physiological traits measured in single leaves of cotton, and related indirectly to plant WUE, indicate potential for genetic advancement through selection. Further studies to determine heritability of these physiological traits in segregating populations are needed to confirm their usefulness in a cotton‐breeding program.
Thirty Years of Change in Forest Soils of the Allegheny Plateau, Pennsylvania
Authors: Bailey S. W. , Horsley S. B. , Long R. P.
Published: May 2005

Numerous studies have investigated the potential depletion of available base cation pools from forest soils in regions impacted by acid deposition. However, these studies mostly used indirect methods. Retrospective studies, providing direct evidence of chemical changes in forest soils, are relatively rare due to a lack of appropriate sampling, documentation, and archiving of samples over decadal or longer periods. We were provided an unusual opportunity to conduct such a retrospective study with relocation of four sites on the Allegheny Plateau in Pennsylvania. Detailed soil sampling and analyses were conducted in 1967. An original investigator was available to insure field sampling protocol consistency during resampling in 1997, and the original samples had been archived and were available for reanalysis. At all four sites there were significant decreases in exchangeable Ca and Mg concentrations and pH at all depths. Exchangeable Al concentrations increased at all depths at all sites, however increases were only significant in upper soil horizons. Short‐term temporal changes, estimated by sampling the Oa/A horizon annually for 3 yr, were insignificant, suggesting that the differences between 1967 and 1997 are part of a long‐term trend. At most of the sites losses of Ca and Mg on a pool basis were much larger than could be accounted for in biomass accumulation, suggesting leaching of nutrients off‐site.
Survey of Water‐Extractable Phosphorus in Livestock Manures
Authors: Kleinman Peter J. A. , Wolf Ann M. , Sharpley Andrew N. , Beegle Douglas B. , Saporito Lou S.
Published: May 2005

Water‐extractable P (WEP) in manure is increasingly used as an environmental indicator as it is correlated with P in runoff from soils recently amended with manure. Little information exists on WEP variability across livestock manures. A survey of 140 livestock manures was conducted to assess trends in WEP (dry weight equivalent) related to livestock types and manure storage. Manure WEP ranged widely (0.2–16.8 g kg−1), with swine (Sus scrofa domestica L.) having the highest average concentrations (9.2 g kg−1), followed by turkey (Melleagris gallopavo) (6.3 g kg−1), layer chickens (Gallus gallus domesticus L.) (4.9 g kg−1), dairy cattle (Bos taurus) (4.0 g kg−1), broiler chickens (Gallus gallus domesticus L.) (3.2 g kg−1), and beef cattle (Bos taurus) (2.3 g kg−1). Manure WEP also differed by general storage system; dry manures contained significantly lower WEP concentrations (3.9 g kg−1) than manure from liquid storage systems (5.4 g kg−1). Within liquid storages, no significant differences in WEP were observed between covered and uncovered storages or between bottom‐loaded and top‐loaded storages. Dry‐matter (DM) content of manure was weakly correlated to WEP across all manures (r = −0.44), but strongly correlated with WEP in liquid swine manure (r = −0.87) and dairy manure (r = −0.72), suggesting dissolution of phosphate compounds as manure solids are diluted in storage. Varying positive correlations were observed between WEP in manure and water‐extractable Ca, Mg, and Fe, or total P, depending on livestock category. Results of this study show that livestock manure can be categorized by WEP, a key step toward differential weighting of agricultural P sources in P site assessment indices.
Modeling Soil Shrinkage Curve across a Wide Range of Soil Types
Authors: Peng X. , Horn R.
Published: May 2005

Knowledge about soil shrinkage improves the understanding and prediction of unsaturated hydraulic properties in nonrigid soils. Until now, there is no general model available, which is widely accepted and applied to quantify soil shrinkage curves. The objectives in this present paper are (i) to propose a new and simple model and to test it with a wide range of soil types; (ii) to mathematically distinguish the shrinkage zones; and (iii) to evaluate probable physical meaning of its parameters. The results show that the modified van Genuchten water retention curve model fits the data obtained from Reeve and Hall's six soils, Talsma's three soils and three Typic Chromexert' soils well and the correlation coefficients in the tested 12 soils are always higher than 0.995. The different shrinkage zones defined by the mathematical method agree well with actual soil shrinkage curve. The proportional shrinkage zone accounts for 30.9 to 79.9% of the total water loss and 63.5 to 93.9% of the total volume decrease, while the zero shrinkage zone only accounts for <2.7% of the total volume decrease. The α, n, and m parameters of the modified van Genuchten model control soil shrinkage curve.
Estimation of Vadose Zone Water Flux from Multi‐Functional Heat Pulse Probe Measurements
Authors: Mori Y. , Hopmans J. W. , Mortensen A. P. , Kluitenberg G. J.
Published: May 2005

A small multi‐functional heat pulse probe (MFHPP) was applied to further develop measurement methodologies to improve on water flux estimations for unsaturated soils. The temperature responses of four thermistors surrounding a central heater in a 2.7‐cm diam. probe were analyzed by the heat transport equation to estimate thermal properties and convective heat flow. Volumetric heat capacity, water content, and thermal diffusivity were estimated from the horizontally placed thermistors, neglecting the convective flow effects in the transverse direction, whereas the water flux density was estimated from the temperature responses to the vertically placed thermistors. A parameter optimization technique was employed to fit the most likely parameters to the relevant analytical solutions. Falling head and multi‐step outflow experiments yielded independently obtained water flux measurements. Results showed that the estimated volumetric water content corresponded well with independent gravimetric measurements with a RMSE of 0.0056 m3 m−3, across a wide range of water fluxes smaller than 0.5 m d−1 Thermal diffusivity values as obtained with the MFHHP also agreed well with independently measured thermal diffusivity values, for water flux density values smaller than 2 m d−1 For saturated conditions, the estimated water fluxes from the MFHPP measurements were accurate in the range between 0.056 and 27.0 m d−1, with a R of 0.995 and RSME of 0.0952 log(m d−1) (0.52 m d−1). For unsaturated flow, MFHHP estimations significantly overestimated water flux density for flux values smaller than 0.10 m d−1 Within these limitations, we conclude that MFHPP methodologies are now available, making possible simultaneous estimation of thermal diffusivity and water flux density in unsaturated soils.