bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost-Effectiveness Analysis of Escitalopram Compared with Paroxetine in Treatment of Generalized Anxiety Disorder in the United Kingdom
Authors: J⊘rgensen Tine Rikke , Stein Dan J , Despiegel Nicolas , Drost Pieter B , Hemels Michiel EH , Baldwin David S
Published: September 2006

Background:

Generalized anxiety disorder (GAD) is associated with substantial economic burden.

Objective:

To assess, from a societal perspective, the cost-effectiveness of escitalopram and paroxetine in the treatment of GAD in the UK.

Method:

A decision analytic model with a 9 month time horizon was adapted to the UK setting. Model inputs included drug- and nondrug-specific probabilities from head-to-head trial data, published literature, and expert opinion. Main outcome measures were success (response after 12 wk of treatment and no relapse during the following 24 wk) and costs. Resource use was based on National Institute for Health and Clinical Excellence guidance for GAD patient management, and estimated unit costs came from standard national sources. Human capital approach was used to estimate costs of absence from work. The analysis was performed from the societal perspective.

Results:

Escitalopram-treated patients were associated with 14.4% higher first-line treatment success and significantly lower discontinuation rates due to adverse events than were those treated with paroxetine. Treatment with escitalopram yielded lower expected costs with greater effectiveness compared with paroxetine. These clinical advantages led to less sick leave and resource use as a result of lower switch rates and use of secondary care. Total expected 9 month costs were £1408 ($2560 US) lower for escitalopram-treated patients than for paroxetine-treated patients. Sensitivity analyses on key parameters demonstrated robustness of the model.

Conclusions:

Escitalopram appears to be cost-effective compared with paroxetine in the treatment of GAD in the UK.
Power of pairwise comparisons in the equal variance and unequal sample size case
Authors: Ramsey Philip H. , Ramsey Patricia P.
Published: September 2006

A Monte Carlo simulation was conducted to compare five, pairwise multiple comparison procedures. The number of means varied from 4 to 6 and the sample size ratio varied from 1 to 60. Procedures were evaluated on the basis of Type I errors, any‐pair power and all‐pairs power. Four procedures were shown to be conservative, while the fifth provided adequate control of Type I errors only for restricted values of sample size ratios. No procedure was found to be uniformly most powerful. The Tukey‐Kramer procedure was found to provide the best any‐pair power provided it is applied without requiring a significant overall F test. In most cases, the Hayter‐Fisher modification of the Tukey‐Kramer was found to provide very good any‐pair power and to be uniformly more powerful than the Tukey‐Kramer when a significant overall F test is required. A partition‐based version of Peritz's method usually provided the greatest all‐pairs power. A modification of the Shaffer‐Welsch was found to be useful in certain conditions.
Does personality explain in‐group identification and discrimination? Evidence from the minimal group paradigm
Authors: Reynolds Katherine J. , Turner John C. , Alexander Haslam S. , Ryan Michelle K. , Bizumic Boris , Subasic Emina
Published: September 2006

The idea that a person's personality can help explain prejudice has a long history in social psychology. The classic counter‐argument has been that prejudice is much more a function of people's group memberships and the nature of intergroup relations rather than individual differences. Bringing these two lines of research together, it has been suggested that personality factors may not only affect intergroup discrimination directly, but also indirectly by predisposing some individuals to identify more strongly with some relevant in‐group membership. Two experiments were conducted to investigate this possibility. The participants completed various personality measures (e.g. authoritarianism, personal need for structure and ethnocentrism as well as social dominance orientation (SDO) in Experiment 2). They were then assigned to minimal groups either randomly, by choice, or (supposedly) on the basis of attitudinal similarity. In Experiment 2, the minimal group paradigm was also adapted to examine the role of SDO. Overall, there was no evidence of significant relationships between traditional personality measures and either in‐group identification or discrimination. In‐group identification alone emerged as the strongest predictor of discrimination. There was evidence that those participants who scored higher in SDO were more likely to act in ways that supported the creation of a power hierarchy. The implications for broader understanding of prejudice are discussed.
Identification of Sequence Motifs That Target Neuronal Nicotinic Receptors to Dendrites and Axons
Authors: Xu Jian , Zhu Yongling , Heinemann Stephen F.
Published: September 2006

Neuronal nicotinic acetylcholine receptors (nAChRs) belong to a family of ligand-gated ion channels that play important roles in central and peripheral nervous systems. The subcellular distribution of neuronal nAChRs has important implications for function and is not well understood. Here, we analyzed the targeting of two major types of neuronal nAChRs by expressing epitope-tagged subunits in cultured hippocampal neurons. Surprisingly, the α7 nAChR (α7) and α4/β2 nAChR (α4β2) displayed distinct patterns of expression, with α7 targeted preferentially to the somatodendritic compartments, whereas α4β2 was localized to both axonal and dendritic domains. When fused to CD4 or IL2RA (interleukin 2 receptor α subunit) proteins, which are normally distributed ubiquitously, the M3–M4 intracellular loop from the α7 subunit promoted dendritic expression, whereas the homologous M3–M4 loop from the α4 subunit led to surface axonal expression. Systemic screening and alanine substitution further identified a 25-residue leucine motif ([DE]XXXL[LI]) containing an axonal targeting sequence within the α4 loop and a 48-residue dileucine and tyrosine motif (YXXØ) containing a dendritic targeting sequence from the α7 loop. These results provide valuable information in understanding diverse roles of neuronal nAChRs in mediating and modulating synaptic transmission, synaptic plasticity, and nicotine addiction.
Triplets of Spikes in a Model of Spike Timing-Dependent Plasticity
Authors: Pfister Jean-Pascal , Gerstner Wulfram
Published: September 2006

Classical experiments on spike timing-dependent plasticity (STDP) use a protocol based on pairs of presynaptic and postsynaptic spikes repeated at a given frequency to induce synaptic potentiation or depression. Therefore, standard STDP models have expressed the weight change as a function of pairs of presynaptic and postsynaptic spike. Unfortunately, those paired-based STDP models cannot account for the dependence on the repetition frequency of the pairs of spike. Moreover, those STDP models cannot reproduce recent triplet and quadruplet experiments. Here, we examine a triplet rule (i.e., a rule which considers sets of three spikes, i.e., two pre and one post or one pre and two post) and compare it to classical pair-based STDP learning rules. With such a triplet rule, it is possible to fit experimental data from visual cortical slices as well as from hippocampal cultures. Moreover, when assuming stochastic spike trains, the triplet learning rule can be mapped to a Bienenstock–Cooper–Munro learning rule.
Schwann Cells Express Motor and Sensory Phenotypes That Regulate Axon Regeneration
Authors: Höke A. , Redett R. , Hameed H. , Jari R. , Zhou C. , Li Z. B. , Griffin J. W. , Brushart T. M.
Published: September 2006

Schwann cell phenotype is classified as either myelinating or nonmyelinating. Additional phenotypic specialization is suggested, however, by the preferential reinnervation of muscle pathways by motoneurons. To explore potential differences in growth factor expression between sensory and motor nerve, grafts of cutaneous nerve or ventral root were denervated, reinnervated with cutaneous axons, or reinnervated with motor axons. Competitive reverse transcription-PCR was performed on normal cutaneous nerve and ventral root and on graft preparations 5, 15, and 30 d after surgery. mRNA for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor, hepatocyte growth factor, and insulin-like growth factor-1 was expressed vigorously by denervated and reinnervated cutaneous nerve but minimally by ventral root. In contrast, mRNA for pleiotrophin (PTN) and glial cell line-derived neurotrophic factor was upregulated to a greater degree in ventral root. ELISA confirmed that NGF and BDNF protein were significantly more abundant in denervated cutaneous nerve than in denervated ventral root, but that PTN protein was more abundant in denervated ventral root. The motor phenotype was not immutable and could be modified toward the sensory phenotype by prolonged reinnervation of ventral root by cutaneous axons. Retrograde labeling to quantify regenerating neurons demonstrated that cutaneous nerve preferentially supported cutaneous axon regeneration, whereas ventral root preferentially supported motor axon regeneration. Schwann cells thus express distinct sensory and motor phenotypes that are associated with the support of regeneration in a phenotype-specific manner. These findings suggest that current techniques of bridging gaps in motor and mixed nerve with cutaneous graft could be improved by matching axon and Schwann cell properties.
A Mirror Representation of Others' Actions in the Human Anterior Parietal Cortex
Authors: Shmuelof Lior , Zohary Ehud
Published: September 2006

The anterior part of the human intraparietal sulcus is known to be involved in visually guided grasping. This region is also active during the observation of object manipulation by others. Here, we explore the nature of action representation using functional magnetic resonance imaging (fMRI). Fourteen subjects observed video clips showing object manipulation by the right or left hand . The clips were presented in either the right or left peripheral visual field. The fMRI activation in the occipital cortex and in the caudal sections of the parietal cortex was specific to the visual-field location of the clips. In contrast, the principal factor determining the response in anterior intraparietal cortex was the identity of the observed hand. Furthermore, these “hand-specific” parietal areas also showed contralateral hand specificity during self action (i.e., object manipulation) without visual feedback. A similar selectivity for the identity of the observed hand was seen when using a region of interest analysis, focusing on individually defined visuomotor voxels within the parietal cortex. This dual visuomotor grasping representation lends further evidence for the existence of a mirror system in humans and suggests that the anterior intraparietal cortex is involved in the specific motor simulation of hand actions.
Area Postrema Neurons Are Modulated by the Adipocyte Hormone Adiponectin
Authors: Fry Mark , Smith Pauline M. , Hoyda Ted D. , Duncan Marnie , Ahima Rexford S. , Sharkey Keith A. , Ferguson Alastair V.
Published: September 2006

Adiponectin is an adipocyte-derived peptide hormone involved in energy homeostasis and the pathogenesis of obesity, including hypertension. Area postrema (AP) lacks a blood–brain barrier and is a critical homeostatic integration center for humoral and neural signals. Here we investigate the role of AP in adiponectin signaling. We show that rat AP expresses AdipoR1 and AdipoR2 adiponectin receptor mRNA. We used current-clamp electrophysiology to investigate whether adiponectin influenced membrane properties of AP neurons and found that ∼60% of rat AP neurons tested were sensitive to adiponectin. Additional electrophysiology experiments coupled with single-cell reverse transcription-PCR indicated that all neurons that expressed both subtypes of receptor were sensitive to adiponectin, whereas neurons expressing only one subtype were predominantly insensitive. Last, microinjection of adiponectin into AP caused significant increases in arterial blood pressure, with no change in heart rate, suggesting that adiponectin acts at AP to provide a possible link between control of energy homeostasis and cardiovascular function.
Protecting Axonal Degeneration by Increasing Nicotinamide Adenine Dinucleotide Levels in Experimental Autoimmune Encephalomyelitis Models
Authors: Kaneko Shinjiro , Wang Jing , Kaneko Marie , Yiu Glenn , Hurrell Joanna M. , Chitnis Tanuja , Khoury Samia J. , He Zhigang
Published: September 2006

Axonal damage is a major morphological alteration in the CNS of patients with multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). However, the underlying mechanism for the axonal damage associated with MS/EAE and its contribution to the clinical symptoms remain unclear. The expression of a fusion protein, named “Wallerian degeneration slow” (Wlds), can protect axons from degeneration, likely through a β-nicotinamide adenine dinucleotide (NAD)-dependent mechanism. In this study, we find that, when induced with EAE,Wldsmice showed a modest attenuation of behavioral deficits and axon loss, suggesting that EAE-associated axon damage may occur by a mechanism similar to Wallerian degeneration. Furthermore, nicotinamide (NAm), an NAD biosynthesis precursor, profoundly prevents the degeneration of demyelinated axons and improves the behavioral deficits in EAE models. Finally, we demonstrate that delayed NAm treatment is also beneficial to EAE models, pointing to the therapeutic potential of NAm as a protective agent for EAE and perhaps MS patients.
Dissociation Between Local Field Potentials and Spiking Activity in Macaque Inferior Temporal Cortex Reveals Diagnosticity-Based Encoding of Complex Objects
Authors: Nielsen Kristina J. , Logothetis Nikos K. , Rainer Gregor
Published: September 2006

Neurons in the inferior temporal (IT) cortex respond selectively to complex objects, and maintain their selectivity despite partial occlusion. However, relatively little is known about how the occlusion of different shape parts influences responses in the IT cortex. Here, we determine experimentally which parts of complex objects monkeys are relying on in a discrimination task. We then study the effect of occlusion of parts with different behavioral relevance on neural responses in the IT cortex at the level of spiking activity and local field potentials (LFPs). For both spiking activity and LFPs, we found that the diagnostic object parts, which were important for behavioral judgments, were preferentially represented in the IT cortex. Our data show that the effects of diagnosticity grew systematically stronger along a posterior–anterior axis for LFPs, but were evenly distributed for single units, suggesting that diagnosticity is first encoded in the posterior IT cortex. Our findings highlight the power of combined analysis of field potentials and spiking activity for mapping structure to computational function in the brain.
Altered Attention and Prefrontal Cortex Gene Expression in Rats after Binge-Like Exposure to Cocaine during Adolescence
Authors: Black Yolanda D. , Maclaren Fair R. , Naydenov Alipi V. , Carlezon William A. , Baxter Mark G. , Konradi Christine
Published: September 2006

Illicit use of drugs frequently begins and escalates during adolescence, with long-term adverse consequences. Because it is increasingly accepted that neural development continues through adolescence, addiction research has become more invested in understanding the behavioral and molecular consequences of early exposure to drugs of abuse. In a novel binge administration paradigm designed to model the pattern of human adolescent drug use, we administered ascending doses of cocaine or saline during a 12-d developmental period [postnatal day 35 (P35) to P46] corresponding to human adolescence. During adulthood (P70), rats treated with this regimen displayed increased responsiveness to the stimulant effects of cocaine. Adult rats also displayed abnormally rapid shifts in attention when performing an attentional set-shifting task, which measures the ability to shift attention between stimuli and whose performance requires an intact prefrontal cortex (PFC). Treatment with cocaine during adolescence also caused acute alterations in the expression of genes encoding cell adhesion molecules and transcription factors within the PFC. Furthermore, we observed decreases in histone methylation, which may indicate a role for chromatin remodeling in the observed changes in gene expression patterns. These findings suggest that exposure to cocaine during adolescence has far-reaching molecular and behavioral consequences in the rat PFC that develop over time and endure long after drug administration has ceased.
Tumor Necrosis Factor Receptor 1 Is a Negative Regulator of Progenitor Proliferation in Adult Hippocampal Neurogenesis
Authors: Iosif Robert E. , Ekdahl Christine T. , Ahlenius Henrik , Pronk Cornelis J. H. , Bonde Sara , Kokaia Zaal , Jacobsen Sten-Eirik W. , Lindvall Olle
Published: September 2006

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine, acting through the TNF-R1 and TNF-R2 receptors. The two receptors have been proposed to mediate distinct TNF-α effects in the CNS, TNF-R1 contributing to neuronal damage and TNF-R2 being neuroprotective. Whether TNF-α and its receptors play any role for neurogenesis in the adult brain is unclear. Here we used mouse models with loss of TNF-R1 and TNF-R2 function to establish whether signaling through these receptors could influence hippocampal neurogenesisin vivounder basal conditions, as well as after status epilepticus (SE), which is associated with inflammation and elevated TNF-α levels. Notably, in the intact brain, the number of new, mature hippocampal neurons was elevated inTNF-R1−/−andTNF-R1/R2−/−mice, whereas no significant changes were detected inTNF-R2−/−mice. Also after SE, theTNF-R1−/−andTNF-R1/R2−/−mice produced more new neurons. In contrast, theTNF-R2−/−mice showed reduced SE-induced neurogenesis. Cell proliferation in the dentate subgranular zone was elevated inTNF-R1−/−andTNF-R1/R2−/−mice both under basal conditions and after SE. TheTNF-R2−/−mice either showed no change or minor decrease of cell proliferation. TNF-R1 and TNF-R2 receptors were expressed by hippocampal progenitors, as assessed with reverse transcription-PCR on sorted or cultured cells and immunocytochemistry on cultures. Our data reveal differential actions of TNF-R1 and TNF-R2 signaling in adult hippocampal neurogenesis and identify for the first time TNF-R1 as a negative regulator of neural progenitor proliferation in both the intact and pathological brain.
Age-Related Changes in Iron Homeostasis and Cell Death in the Cerebellum of Ceruloplasmin-Deficient Mice
Authors: Jeong Suh Young , David Samuel
Published: September 2006

Iron is essential for a variety of cellular functions, but its levels and bioavailability must be tightly regulated because of its toxic redox activity. A number of transporters, binding proteins, reductases, and ferroxidases help maintain iron homeostasis to prevent cell damage. The multi-copper ferroxidase ceruloplasmin (Cp) converts toxic ferrous iron to its nontoxic ferric form and is required for iron efflux from cells. Absence of this enzyme in humans leads to iron accumulation and neurodegeneration in the CNS. Here we report on the changes that occur in the cerebellum of Cp null (Cp−/−) mice with aging. We show that iron accumulation, which is reflected in increased ferritin expression, occurs mainly in astrocytes by 24 months inCp−/−mice and is accompanied by a significant loss of these cells. In contrast, Purkinje neurons and the large neurons in the deep nuclei ofCp−/−mice do not accumulate iron but express high levels of the iron importer divalent metal transporter 1, suggesting that these cells may be iron deprived. This is also accompanied by a significant reduction in the number of Purkinje neurons. These data suggest that astrocytes play a central role in the acquisition of iron from the circulation and that two different mechanisms underlie the loss of astrocytes and neurons inCp−/−mice. These findings provide a better understanding of the degenerative changes seen in humans with aceruloplasminemia and have implications for normal aging and neurodegenerative diseases in which iron accumulation occurs.
Modulation of Transient and Sustained Response Components of V4 Neurons by Temporal Crowding in Flashed Stimulus Sequences
Authors: Motter Brad C.
Published: September 2006

The responses of extrastriate area V4 neurons to flashed visual stimuli were examined to determine whether the responses to stimulus sequences occurring at normal saccade and fixation timing intervals were degraded relative to longer timing intervals. Stimuli were flashed in receptive fields in the near periphery while monkeys maintained steady fixation. Short interstimulus intervals (ISIs) resulted in an overall habituation style response reduction. The transient component of responses to preferred stimuli was suppressed, often completely, when the ISI was reduced below 100 ms into the range of saccadic durations. The sustained response component weakened but remained intact. At short ISIs the trailing activity from the preceding stimulus blended with onset activity from the next stimulus, making it difficult to detect individual stimulus onset events within the spike train. Habituation or conditioning effects were correlated with the stimulus tuning sensitivity of the neuron but only loosely associated with the actual level of V4 activation elicited by preceding stimuli. The results suggest that sharply tuned neurons, because of their probabilistic inactivity, are particularly sensitive to temporal change, whereas the sustained components of broadly tuned neurons could provide a continuity of information flow across visual transients, such as saccades, that do not alter significantly the view by the neuron of the scene.
Integrated Neural Processes for Defining Potential Actions and Deciding between Them: A Computational Model
Authors: Cisek Paul
Published: September 2006

To successfully accomplish a behavioral goal such as reaching for an object, an animal must solve two related problems: to decide which object to reach and to plan the specific parameters of the movement. Traditionally, these two problems have been viewed as separate, and theories of decision making and motor planning have been developed primarily independently. However, neural data suggests that these processes involve the same brain regions and are performed in an integrated manner. Here, a computational model is described that addresses both the question of how different potential actions are specified and how the brain decides between them. In the model, multiple potential actions are simultaneously represented as continuous regions of activity within populations of cells in frontoparietal cortex. These representations engage in a competition for overt execution that is biased by modulatory influences from prefrontal cortex. The model neural populations exhibit activity patterns that correlate with both the spatial metrics of potential actions and their associated decision variables, in a manner similar to activities in parietal, prefrontal, and premotor cortex. The model therefore suggests an explanation for neural data that have been hard to account for in terms of serial theories that propose that decision making occurs before action planning. In addition to simulating the activity of individual neurons during decision tasks, the model also reproduces key aspects of the spatial and temporal statistics of human choices and makes a number of testable predictions.
Out of the Past, Into the Supermarket
Authors: DUSSERE ERIK
Published: September 2006

ABSTRACT This article traces film noir's conflicted place in postwar American consumer culture.Using detailed analyses of supermarket scenes in Double Indemnity, The Long Goodbye, and Fight Club, it argues that the films stage a struggle between two competing versions of the American national character: the consumer society versus the noir underworld.
Stanley Kubrick and the Aesthetics of the Grotesque
Authors: NAREMORE JAMES
Published: September 2006

ABSTRACT “The grotesque,” which became a stylistic term in the Italian renaissance and later contributed significantly to all forms of modernist art, can help us better understand the so-called “coldness” often attributed to Stanley Kubrick's films. The whole of Kubrick's art is designed to produce a grotesque clash of emotions, an unstable blending of humor and terror that derives ultimately from anxieties about the human body.
Dog Days (Hundstage)
Authors: VICARI JUSTIN
Published: September 2006

ABSTRACT In Dog Days, graphic sex and violence are presented as the only elements in life that are not banal, prepackaged “factoids.” Observing his documentary-like tapestry of characters in various stages of coupling and uncoupling, director Ulrich Seidl suggests that sadomasochism could almost be considered an inevitable, universal condition.
No Man's Land (Nikogarŝnja zemlja)
Authors: CORBIN AMY
Published: September 2006

ABSTRACT Set during the Bosnian-Serbian war, No Man's Land is an intimate drama of two opposing soldiers stuck in a trench. The peripheral presence of clumsy U.N. commanders and overly dramatic TV journalists contributes to a satirical and wrenching look at the intertwined nature of war, global power, and the media.
William Shakespeare's The Merchant of Venice
Authors: DANIEL DREW
Published: September 2006

ABSTRACT Lingering controversy about anti-Semitism has kept The Merchant of Venice off the screen. Michael Radford's 2004 film adaptation creates a critique of anti-Semitic violence revealingly at odds with the play's comic form. This review considers the challenge Shakespeare's art poses to the ethical imperatives of contemporary filmmaking.
A Sequence-Tagged Linkage Map ofBrassica rapa
Authors: Kim Jung Sun , Chung Tae Young , King Graham J , Jin Mina , Yang Tae-Jin , Jin Yong-Moon , Kim Ho-Il , Park Beom-Seok
Published: September 2006

A detailed genetic linkage map of Brassica rapa has been constructed containing 545 sequence-tagged loci covering 1287 cM, with an average mapping interval of 2.4 cM. The loci were identified using a combination of 520 RFLP and 25 PCR-based markers. RFLP probes were derived from 359 B. rapa EST clones and amplification products of 11 B. rapa and 26 Arabidopsis. Including 21 SSR markers provided anchors to previously published linkage maps for B. rapa and B. napus and is followed as the referenced mapping of R1–R10. The sequence-tagged markers allowed interpretation of the pattern of chromosome duplications within the B. rapa genome and comparison with Arabidopsis. A total of 62 EST markers showing a single RFLP band were mapped through 10 linkage groups, indicating that these can be valuable anchoring markers for chromosome-based genome sequencing of B. rapa. Other RFLP probes gave rise to 2–5 loci, inferring that B. rapa genome duplication is a general phenomenon through 10 chromosomes. The map includes five loci of FLC paralogues, which represent the previously reported BrFLC-1, -2, -3, and -5 and additionally identified BrFLC3 paralogues derived from local segmental duplication on R3.
Sometimes the Result Is Not the Answer: The Truths and the Lies That Come From Using the Complementation Test
Authors: Hawley R Scott , Gilliland William D
Published: September 2006

It is standard genetic practice to determine whether or not two independently obtained mutants define the same or different genes by performing the complementation test. While the complementation test is highly effective and accurate in most cases, there are a number of instances in which the complementation test provides misleading answers, either as a result of the failure of two mutations that are located in different genes to complement each other or by exhibiting complementation between two mutations that lie within the same gene. We are primarily concerned here with those cases in which two mutations lie in different genes, but nonetheless fail to complement each other. This phenomenon is often referred to as second-site noncomplementation (SSNC). The discovery of SSNC led to a large number of screens designed to search for genes that encode interacting proteins. However, screens for dominant enhancer mutations of semidominant alleles of a given gene have proved far more effective at identifying interacting genes whose products interact physically or functionally with the initial gene of interest than have SSNC-based screens.
Evaluation of Glyphosate-Resistant Hard Red Spring Wheat (Triticum aestivum)
Authors: Howatt Kirk A. , Endres Gregory J. , Hendrickson Paul E. , Aberle Ezra Z. , Lukach John R. , Jenks Brian M. , Riveland Neil R. , Valenti Stephen A. , Rystedt Craig M.
Published: September 2006

The potential for future commercialization of glyphosate-resistant wheat necessitates evaluation of agronomic merits of this technology. Experiments were established to evaluate glyphosate-resistant wheat and weed responses to glyphosate rate, application timing, and tank mixtures. Glyphosate at 1,680 g/ha did not injure wheat. Wheat response to glyphosate applied to one- to three- or three- to five-leaf wheat was not different from that of untreated wheat. Wheat was injured more from glyphosate plus thifensulfuron or glyphosate plus dicamba than from individual herbicides at one of six locations, but grain yield was not affected by glyphosate tank mixtures. Glyphosate application timing did not affect control of wild oat or common lambsquarters 56 d after treatment. Glyphosate when applied to one- to three-leaf wheat provided better control of wild buckwheat than later glyphosate application, whereas glyphosate applied to three- to five-leaf wheat provided the best control of green and yellow foxtail, redroot pigweed, and Canada thistle. Weed control with glyphosate tended to be better than with conventional herbicides, and wheat treated with glyphosate produced approximately 10% more grain than wheat treated with conventional herbicide tank mixes.
Options for Cogongrass (Imperata cylindrica) Control in White Guinea Yam (Dioscorea rotundata) and Cassava (Manihot esculenta)
Authors: Chikoye David , Ellis-Jones Jim , Kormawa Patrick , Udensi Udensi E. , Ibana Simon E. , Avav Ter-Rumun
Published: September 2006

Cogongrass is a serious weed in small-scale farms in the lowland humid zone of West Africa. This study evaluated the response of cogongrass to herbicides and the legume cover crop velvetbean in cassava and white Guinea yam. In 2001/2002, cassava tuber yields and gross returns in treatments that received glyphosate alone were higher than in plots that received fluazifop-P-butyl once. In 2002/2003, treatments that received fluazifop-P-butyl once, glyphosate alone, glyphosate integrated with sowing velvetbean, or hoeing only, had higher cassava tuber yields than other treatments. Gross returns were higher in treatments that received glyphosate followed by sowing velvetbean or those hoed only than in other treatments. Fluazifop-P-butyl applied twice, glyphosate alone, or glyphosate followed by sowing velvetbean reduced cogongrass shoot biomass more than other treatments. Rhizome biomass was lower in plots that received glyphosate alone than in all fluazifop-P-butyl treatments. In 2002, white Guinea yam tuber yields were highest in plots that received glyphosate alone and lowest in plots where fluazifop-P-butyl was applied alone or followed by sowing velvetbean. The highest gross return was obtained in plots that received glyphosate alone while the lowest was obtained in plots that received fluazifop-P-butyl once followed by sowing velvetbean. In 2003, the highest tuber yields and gross returns were from plots that received glyphosate alone, fluazifop-P-butyl alone, or those hoed only. The hoed-only plots had 14 times higher cogongrass shoot biomass and 7 times higher rhizome biomass than other treatments. In both crops, hoeing alone or followed by sowing velvetbean was more costly than chemical control. The highest margin over hoeing was obtained from plots that received glyphosate alone. Sensitivity analysis showed that using glyphosate was more cost effective than fluazifop-P-butyl, even if the cost of the herbicide increased by 100% or the cost of labor decreased by 30%.
Influence of Crownbeard (Verbesina encelioides) Densities on Peanut (Arachis hypogaea) Yield
Authors: Farris Rodney L. , Murray Don S.
Published: September 2006

Field experiments were conducted at the Caddo Research Station near Ft. Cobb, OK and at the Agronomy Research Station near Perkins, OK to measure the effects of seven crownbeard (Verbesina encelioides) densities on peanut (Arachis hypogaea) yield. The seven densities evaluated were 0 (the weed-free check), 0.2, 0.4, 0.8, 1.6, 2.4, and 3.2 weeds/m of row. Data collected consisted of dry weed biomass and peanut yields. Correlation between weed density and dry weed biomass, dry weed biomass and peanut yield (kg/ha), dry weed biomass and peanut yield loss (percentage of check), weed density and peanut yield (kg/ha), and weed density and peanut yield loss (percentage of check) were evaluated. For each weed/m of row, dry weed biomass increased by 0.34 kg/m row. Dry weed biomass was a good predictor of peanut yield. For each kilogram of dry weed biomass/ m row, a 1900-kg/ha or 46.3% reduction in peanut yield occurred. Weed density was also a good predictor of peanut yield. A 559-kg/ha reduction or 16% increase in peanut yield loss occurred for each weed/m row. Peanut yield was reduced approximately 50% when crownbeard density increased to 3.2 weeds/m row.
Seasonal Effects on Annual Bluegrass (Poa annua) Control in Creeping Bentgrass with Bispyribac-Sodium
Authors: Lycan Darren W. , Hart Stephen E.
Published: September 2006

Studies were conducted in 2002 and 2003 on a golf course fairway in New Jersey to compare spring, summer, and fall treatments of bispyribac-sodium for annual bluegrass control and creeping bentgrass tolerance. Single applications at 74, 111, or 148 g ai/ha were applied in May, August, or October. Split applications of 37 followed by (fb) 37 or 74 fb 74 g/ha applied 3 wk apart were also evaluated. Summer-applied bispyribac-sodium did not reduce bentgrass quality, whereas spring and fall treatments reduced turf quality at 3 wk after treatment and fall treatments in 2002 substantially reduced bentgrass quality. Summer treatments were more effective than spring or fall treatments in reducing annual bluegrass cover. Final evaluations revealed 36, 31, 21, and 26% annual bluegrass cover averaged across nontreated, spring-treated, summer-treated, and fall-treated plots, respectively. This study demonstrates that two split applications of bispyribac-sodium at 74 g/ha in summer can effectively reduce annual bluegrass cover while minimizing creeping bentgrass injury.
Microtopography, Microenvironments, and Weed Populations in Ridge-Tilled Soybean
Authors: Jurik Thomas W.
Published: September 2006

The effects of microtopographic position on soil microenvironment and weed populations in ridge-tilled soybean were evaluated on three farms in Iowa in 1989 and 1990. In both years, over all weed species (primarily giant foxtail, green foxtail, yellow foxtail, redroot pigweed, and Pennsylvania smartweed), seedling emergence was highest in late May and early June, with few seedlings emerging after mid-June. Weed populations were highest in May and early June, after which rotary hoeing and cultivation reduced weed numbers in all plots. Microtopographic position (row, shoulder, and furrow) had a large effect on soil microenvironment and weed populations. Furrows were the wettest position through most of the growing season. Rows were the warmest position early in the season and the coolest position late in the season. Cumulative weed emergence early in the season was closely related to growing degree days, which accumulated faster in the row position than the furrow position. Following rotary hoeing and cultivation, the row position had significantly more total weeds than the shoulder and furrow positions on all farms in August of both years.
Comparison of Mesotrione Combinations with Standard Weed Control Programs in Corn
Authors: Whaley Cory M. , Armel Gregory R. , Wilson Henry P. , Hines Thomas E.
Published: September 2006

Field experiments were conducted in 2002 and 2003 to evaluate total POST weed control in corn with mixtures of mesotrione, atrazine, and the commercial mixture of nicosulfuron plus rimsulfuron plus atrazine at registered and reduced rates. Treatments were compared with nicosulfuron plus rimsulfuron plus atrazine POST, andS-metolachlor plus atrazine PRE alone and followed by (fb) nicosulfuron plus rimsulfuron plus atrazine POST. All treatments controlled common lambsquarters 8 wk after the postemergence treatments (WAPT). Common ragweed control with POST mesotrione plus nicosulfuron plus rimsulfuron plus atrazine combinations was greater than 89%. Mesotrione plus the registered rate of nicosulfuron plus rimsulfuron plus atrazine POST controlled common ragweed more effectively than the PRE treatment alone. Addition of atrazine to mesotrione improved common ragweed control by at least 38 percentage points over mesotrione alone. Nicosulfuron plus rimsulfuron plus atrazine at the registered rate and in mixtures with mesotrione controlled morningglory species (pitted and ivyleaf morningglory) 89 to 91%. Large crabgrass control varied between 2002 and 2003. In 2002, large crabgrass control was 58 to 76% with all POST treatments, but in 2003, nicosulfuron plus rimsulfuron plus atrazine POST alone controlled large crabgrass greater than 86%. Large crabgrass was more effectively controlled by treatments withS-metolachlor plus atrazine PRE than by the total POST treatments in 2002. Giant foxtail was controlled at least 97% with nicosulfuron plus rimsulfuron plus atrazine treatments.S-metolachlor plus atrazine PRE fb nicosulfuron plus rimsulfuron plus atrazine POST controlled all weed species greater than 85%. Corn yields by total POST treatment combinations of mesotrione plus either rate of nicosulfuron plus rimsulfuron plus atrazine were comparable toS-metolachlor plus atrazine PRE alone or fb nicosulfuron plus rimsulfuron plus atrazine POST.
KIH-485 and S-metolachlor Efficacy Comparisons in Conventional and No-Tillage Corn
Authors: Geier Patrick W. , Stahlman Phillip W. , Frihauf John C.
Published: September 2006

Field experiments were conducted during 2003 and 2004 to compare the effectiveness of KIH-485 and S-metolachlor for PRE weed control in no-tillage and conventional-tillage corn. Longspine sandbur control increased as KIH-485 or S-metolachlor rates increased in conventional-tillage corn, but control did not exceed 75% when averaged over experiments. Both herbicides controlled at least 87% of green foxtail with the exception of no-tillage corn in 2004, when KIH-485 was more effective than S-metolachlor at lower rates. Palmer amaranth control ranged from 85 to 100% in 2003 and 80 to 100% in 2004, with the exception of only 57 to 76% control at the lowest two S-metolachlor rates in 2004. Puncturevine control exceeded 94% with all treatments in 2003. In 2004, KIH-485 controlled 86 to 96% of the puncturevine, whereas S-metolachlor controlled only 70 to 81%. Mixtures of atrazine with KIH-485 or S-metolachlor generally provided the most effective control of broadleaf weeds studied.
Herbicide-Resistant Canola (Brassica napus) Response and Weed Control with Postemergence Herbicides
Authors: Grey Timothy L. , Raymer Paul L. , Bridges David C.
Published: September 2006

Field studies were conducted to evaluate weed control in herbicide-resistant canola in Georgia. The resistant canola cultivars and respective herbicides were ‘Pioneer 45A76’ and imazamox, ‘Hyola 357RR’ and glyphosate, and ‘2573 Invigor’ and glufosinate. Weed seed of Italian ryegrass and wild radish were sown simultaneously in October with canola and control of these species was evaluated along with other naturally occurring weeds. Herbicide treatments for the respective herbicide-resistant canola cultivar were imazamox at 0.035 and 0.071 kg ai/ha, glyphosate at 0.84 and 1.64 kg ae/ha, and glufosinate at 0.5 and 1.0 kg ai/ha. Herbicides were applied at one– two-leaf (LF) and three–four-LF canola stages. There was no significant injury to any canola cultivar as a result of herbicide rate or timing of application. By midseason (February), imazamox effectively controlled wild radish, henbit, and shepherd's-purse at both rates and at both timings. When applied to three–four-LF canola, the higher rates of glyphosate and glufosinate were required to provide 75% or greater control of Italian ryegrass, wild garlic, and henbit. Glufosinate did not adequately control wild radish at either rate or application timing. Greenhouse experiments provided similar results.
Characterization of Spontaneous Crosses between Clearfield Rice (Oryza sativa) and Red Rice (Oryza sativa)
Authors: Shivrain Vinod K. , Burgos Nilda R. , Moldenhauer Karen A. K. , Mcnew Ronald W. , Baldwin Tomilea L.
Published: September 2006

Experiments were conducted to determine the inheritance of resistance in crosses between imazethapyr-resistant rice and red rice. Past experiments on red rice control, using the Clearfield rice technology, resulted in outcrossing between Clearfield rice and Stuttgart strawhull red rice. The F2 generation of these spontaneous crosses were characterized with respect to inheritance of imazethapyr resistance, leaf color and leaf pubescence, and seed shattering, pubescence, color, and size. Agronomic traits of hybrids were also observed in relation to their parents. To determine the segregation of resistance among F2 phenotypes, the response of three- to four-leaf plants to imazethapyr was scored 3 wk after application as resistant (R, no imazethapyr symptoms), susceptible (S, death of plants), or intermediate (I, stunted plants). R, I, and S phenotypes segregated in a 1:2:1 ratio in the F2 generation. Two- or three-gene inheritance was documented for leaf and seed characteristics. A wide range in onset of flowering (70 to 130 d after planting) was observed in F2 families, although 6% of the plants did not flower during the growing season. F2 plants were taller and had more tillers than any of their parents. Resistance to imazethapyr is associated with a single, incompletely dominant allele.
Hoary Cress (Cardaria draba) Control in Winter Wheat with Postemergence Herbicides
Authors: Vasilakoglou Ioannis B. , Dhima K. V. , Eleftherohorinos I. G.
Published: September 2006

Field experiments were conducted during 3 yr in Thessaloniki, northern Greece, to determine the efficacy of various herbicides applied alone or in mixtures POST on hoary cress grown in winter wheat. Also, the efficacy of these herbicides on hoary cress generated from seed or root fragments was investigated in pot experiments. All herbicides except for ioxynil plus bromoxynil provided 90 to 100% control of hoary cress generated from seed and root fragments grown in pots. Ioxynil plus bromoxynil gave 84% control of hoary cress generated from seed, but only 66% control of plants generated from root fragments. In the field, mecoprop plus dicamba, imazamethabenz plus mecoprop plus dicamba, and triclopyr applied at the four- to eight-leaf stage provided, respectively, 87, 76, and 83% control of hoary cress (averaged over year and assessment time). Thifensulfuron plus tribenuron provided only 29% control. Chlorsulfuron plus dicamba, clopyralid plus MCPA, 2,4-D plus metosulam, and fluroxypyr provided intermediate hoary cress control. Furthermore, the least hoary cress emergence 52 wk after treatment appeared in plots treated with triclopyr. In addition, wheat grown in plots treated with mecoprop plus dicamba yielded more than wheat treated with the other herbicide treatments, and 55% more than wheat grown in nontreated plots. The results of this study indicate that very good control of hoary cress and high wheat yield can be obtained by the application of mecoprop plus dicamba at the four- to eight-leaf weed growth stage.
Validation of Weed Competitive Indices for Predicting Peanut Yield Losses in Oklahoma
Authors: Willis John B. , Murray Don S. , Murdock Shea W.
Published: September 2006

Weed interference experiments have not been extensively conducted in Oklahoma peanut. Research was conducted in three environments to evaluate usefulness of single-weed density experiments with the use of several weeds to measure their relative competitive abilities with a crop. These data can be used to validate current competitive indices (CIs) used by a model to predict peanut yield loss due to weeds. This model is used by the Herbicide Application Decision Support System (HADSS) and Pesticide Economic and Environmental Tradeoffs (PEET), two decision-support systems (DSSs) available for Oklahoma peanut. Six weeds common in Oklahoma peanut were used: crownbeard, eclipta, ivyleaf morningglory, johnsongrass, Palmer amaranth, and prickly sida plus two others, barnyardgrass and common cocklebur, as benchmark species. Each weed was planted into peanut uniformly at eight weeds/10 m of row. Dry weed biomass accounted for 77 to 90% of variation in in-shell peanut yield loss; however, model parameters only allow for weed number. Yield losses from these experiments were compared to those predicted by the model to test original CI accuracy. Treatment means were compared to the prediction model with the use of protected LSD. Several significant differences were noted, and the CIs for those weed species were adjusted accordingly. Adjusting CIs improved actual yield data goodness of fit to model predictions specific to environment in question, but not necessarily in different environments. The CI changed at Ft. Cobb were eclipta from 1.8 to 4.5 and ivyleaf morningglory from 3.4 to 5.0. CI adjustments at Perkins were common cocklebur from 10.0 to 5.8 and johnsongrass from 3.0 to 4.6. Collecting data for several weed species at uniform density in a crop provides a more time-efficient method for obtaining accurate relative weed interference data; this method is useful in validating or establishing CI lists in areas and/or crops with limited data.
Influence of Diclosulam Postemergence Application Timing on Weed Control and Peanut Tolerance
Authors: Everman Wesley J. , Clewis Scott B. , Taylor Zachary G. , Wilcut John W.
Published: September 2006

Field studies were conducted at Lewiston–Woodville and Rocky Mount, NC in 2001 and 2002 to evaluate weed control and peanut response to POST treatments of diclosulam at various rates and application timings. Diclosulam controlled common ragweed and entireleaf morningglory when applied within 35 d after planting (DAP). Common ragweed 61 cm tall was controlled ≥92% with 4 to 13 g ai/ha diclosulam and larger common ragweed (107 to 137 cm tall) were controlled ≥97% with 27 g/ha diclosulam. Common lambsquarters was controlled 62% or less with all diclosulam POST treatments following metolachlor applied PRE, which provided 48% control. Peanut injury was less than 15% with all diclosulam POST treatments and was transitory. In separate studies, POST diclosulam treatments did not affect peanut yield in a weed-free environment. Peanut yield in weedy environments was reduced as the diclosulam application timing was delayed because of early season weed interference. A linear relationship was observed between yield and application timing with yield decreasing as application timing was delayed. This yield response documents the importance of early season weed management for maximizing peanut yield potential. Virginia peanut varieties were not affected by different POST rates of diclosulam; however, early season peanut injury showed a linear and quadratic relationship with diclosulam rate and was less than 14% at rates as high as 71 g/ha, and was not apparent by late season.