bluuebunny/crossref_metadata_2025 huggingface dataset:
Qualitative network models and genome-wide expression data define carbon/nitrogen-responsive molecular machines in Arabidopsis
Authors: Gutiérrez Rodrigo A , Lejay Laurence V , Dean Alexis , Chiaromonte Francesca , Shasha Dennis E , Coruzzi Gloria M
Published: January 2007

Background

Carbon (C) and nitrogen (N) metabolites can regulate gene expression in Arabidopsis thaliana. Here, we use multinetwork analysis of microarray data to identify molecular networks regulated by C and N in the Arabidopsis root system.

Results

We used the Arabidopsis whole genome Affymetrix gene chip to explore global gene expression responses in plants exposed transiently to a matrix of C and N treatments. We used ANOVA analysis to define quantitative models of regulation for all detected genes. Our results suggest that about half of the Arabidopsis transcriptome is regulated by C, N or CN interactions. We found ample evidence for interactions between C and N that include genes involved in metabolic pathways, protein degradation and auxin signaling. To provide a global, yet detailed, view of how the cell molecular network is adjusted in response to the CN treatments, we constructed a qualitative multinetwork model of the Arabidopsis metabolic and regulatory molecular network, including 6,176 genes, 1,459 metabolites and 230,900 interactions among them. We integrated the quantitative models of CN gene regulation with the wiring diagram in the multinetwork, and identified specific interacting genes in biological modules that respond to C, N or CN treatments.

Conclusion

Our results indicate that CN regulation occurs at multiple levels, including potential post-transcriptional control by microRNAs. The network analysis of our systematic dataset of CN treatments indicates that CN sensing is a mechanism that coordinates the global and coordinated regulation of specific sets of molecular machines in the plant cell.
Role of human neutrophil peptides in the initial interaction between lung epithelial cells and CD4+ lymphocytes
Authors: Vaschetto Rosanna , Grinstein Jonathan , Del Sorbo Lorenzo , Khine Aye Aye , Voglis Stefanos , Tullis Elizabeth , Slutsky Arthur S , Zhang Haibo
Published: January 2007

Human neutrophil peptides (HNP) exert immune-modulating effects. We hypothesized that HNP link innate and adaptive immunity through activation of costimulatory molecules. Human lung epithelial cells and CD4+ lymphocytes were treated with HNP separately or in coculture. Stimulation with HNP induced an increase in cell surface expression of CD54 (ICAM-1), CD80, and CD86 on lung epithelial cells and the corresponding major ligands, CD11a (LFA-1), CD152 (CTLA-4), and CD28 on CD4+ lymphocytes. There was an increased nuclear expression of the transcription factor p53 in human alveolar A549 cells and an elevated NF-κB (p50) and a degradation of I-κB protein in CD4+ lymphocytes following HNP stimulation. HNP enhanced the interaction between A549 cells and CD4+ lymphocytes by increasing cell adhesion and release of IFN-γ, IL-2, and IL-8. This was attenuated by using an α1-proteinase inhibitor to neutralize HNP. We conclude that HNP play an important role in linking innate to acquired immunity by activation of costimulatory molecules in lung epithelial cells and CD4+ lymphocytes.
Angiopoietin chemotactic activities on neutrophils are regulated by PI-3K activation
Authors: Brkovic Alexandre , Pelletier Martin , Girard Denis , Sirois Martin G
Published: January 2007

Angiopoietins (Ang1 and Ang2) modulate blood vessel integrity during the angiogenic process through the activation of tyrosine kinase receptor (Tie2). We recently detected Tie2 expression on neutrophils and reported that angiopoietins induce acute proinflammatory events including neutrophil β2-integrin activation and their adhesion onto endothelial cells. Herein, we investigated the effect of angiopoietins on neutrophil migration and their capacity to modulate CXCL8/IL-8 chemotactic properties. Using a Boyden chamber assay, we observed that Ang1 and Ang2 (up to 10 nM; 60 min) increased the migration of neutrophils, and the maximal effect was achieved at 1 nM (72% and 114% increase, respectively) as compared with untreated cells. Angiopoietins induce a rapid and transient Akt phosphorylation, and pretreatment of neutrophils with PI-3K inhibitors, wortmannin (100 nM) and LY294002 (500 nM), reduced Ang1-mediated neutrophil migration by 100% and 78% and Ang2 chemotactic activity by 100% and 71%, respectively. Treatment of neutrophils with CXCL8/IL-8 (up to 50 nM; 60 min) increased basal neutrophil migration by 257% at its optimal concentration (10 nM), and pretreatment of neutrophils with corresponding PI-3K inhibitors reduced CXCL8/IL-8 (1 nM) chemotactic effect. Pretreatment of neutrophils with Ang1 or Ang2 (10 nM; 15 min) potentiated neutrophil migration induced by CXCL8/IL-8 (1 or 10 nM; 60 min) by 263% and 238% and by 177% and 164%, respectively. Finally, both angiopoietins showed a synergistic effect on the induction of Akt phosphorylation mediated by CXCL8/IL-8. In summary, our data demonstrate that angiopoietins increase neutrophil migration through PI-3K activation and can enhance proinflammatory activities of other cytokines.
Auxin-dependent regulation of lateral root positioning in the basal meristem ofArabidopsis
Authors: De Smet Ive , Tetsumura Takuya , De Rybel Bert , Frey Nicolas Frei dit , Laplaze Laurent , Casimiro Ilda , Swarup Ranjan , Naudts Mirande , Vanneste Steffen , Audenaert Dominique , Inzé Dirk , Bennett Malcolm J. , Beeckman Tom
Published: January 2007

In plants, the developmental mechanisms that regulate the positioning of lateral organs along the primary root are currently unknown. We present evidence on how lateral root initiation is controlled in a spatiotemporal manner in the model plant Arabidopsis thaliana. First, lateral roots are spaced along the main axis in a regular left-right alternating pattern that correlates with gravity-induced waving and depends on AUX1, an auxin influx carrier essential for gravitropic response. Second, we found evidence that the priming of pericycle cells for lateral root initiation might take place in the basal meristem, correlating with elevated auxin sensitivity in this part of the root. This local auxin responsiveness oscillates with peaks of expression at regular intervals of 15 hours. Each peak in the auxin-reporter maximum correlates with the formation of a consecutive lateral root. Third, auxin signaling in the basal meristem triggers pericycle cells for lateral root initiation prior to the action of INDOLE-3-ACETIC ACID14(SOLITARY ROOT).
The zebrafishzic2a-zic5gene pair acts downstream of canonical Wnt signaling to control cell proliferation in the developing tectum
Authors: Nyholm Molly K. , Wu Shan-Fu , Dorsky Richard I. , Grinblat Yevgenya
Published: January 2007

Wnt growth factors acting through the canonical intracellular signaling cascade play fundamental roles during vertebrate brain development. In particular, canonical Wnt signaling is crucial for normal development of the dorsal midbrain, the future optic tectum. Wnts act both as patterning signals and as regulators of cell growth. In the developing tectum, Wnt signaling is mitogenic; however, the mechanism of Wnt function is not known. As a step towards better understanding this mechanism, we have identified two new Wnt targets, the closely linked zic2a and zic5 genes. Using a combination of in vivo assays, we show that zic2a and zic5transcription is activated by Tcf/Lef transcription factors in the dorsal midbrain. Zic2a and Zic5, in turn, have essential, cooperative roles in promoting cell proliferation in the tectum, but lack obvious patterning functions. Collectively these findings suggest that Wnts control midbrain proliferation, at least in part, through regulation of two novel target genes,the zic2a-zic5 gene pair.
The Ovhts polyprotein is cleaved to produce fusome and ring canal proteins required forDrosophilaoogenesis
Authors: Petrella Lisa N. , Smith-Leiker Tracy , Cooley Lynn
Published: January 2007

An essential component of normal development is controlling the transition from cell proliferation to differentiation. One such transition occurs during Drosophila oogenesis. In early oogenesis, germ cells undergo mitotic proliferation and contain a specialized organelle called a fusome, whereas later post-mitotic cells differentiate and lose the fusome as F-actin-rich ring canals form. The hts gene encodes the only DrosophilaAdducin, and is a female-sterile mutant that affects both the fusome and ring canals. We show that one Hts protein, Ovhts, is a polyprotein that is cleaved to produce two products, Ovhts-Fus and Ovhts-RC. Whereas Ovhts-Fus localizes to the fusome in mitotic cells, Ovhts-RC localizes to ring canals throughout later oogenesis. We demonstrate that an uncleavable version of Ovhts delays the transition from fusome-containing cells to those that have ring canals. Ovhts is the first polyprotein shown to produce proteins that function in separate structures.
SEL-2, theC. elegansneurobeachin/LRBA homolog, is a negative regulator oflin-12/Notchactivity and affects endosomal traffic in polarized epithelial cells
Authors: de Souza Natalie , Vallier Laura G. , Fares Hanna , Greenwald Iva
Published: January 2007

The vulval precursor cells (VPCs) of Caenorhabditis elegans are polarized epithelial cells that adopt a precise pattern of fates through regulated activity of basolateral LET-23/EGF receptor and apical LIN-12/Notch. During VPC patterning, there is reciprocal modulation of endocytosis and trafficking of both LET-23 and LIN-12. We identified sel-2 as a negative regulator of lin-12/Notch activity in the VPCs, and found that SEL-2 is the homolog of two closely related human proteins, neurobeachin(also known as BCL8B) and LPS-responsive, beige-like anchor protein (LRBA). SEL-2, neurobeachin and LRBA belong to a distinct subfamily of BEACH-WD40 domain-containing proteins. Loss of sel-2 activity leads to basolateral mislocalization and increased accumulation of LIN-12 in VPCs in which LET-23 is not active, and to impaired downregulation of basolateral LET-23 in VPCs in which LIN-12 is active. Downregulation of apical LIN-12 in the VPC in which LET-23 is active is not affected. In addition, in sel-2 mutants, the polarized cells of the intestinal epithelium display an aberrant accumulation of the lipophilic dye FM4-64 when the dye is presented to the basolateral surface. Our observations indicate that SEL-2/neurobeachin/LRBA is involved in endosomal traffic and may be involved in efficient delivery of cell surface proteins to the lysosome. Our results also suggest that sel-2 activity may contribute to the appropriate steady-state level of LIN-12 or to trafficking events that affect receptor activation.
C. elegansEVI1 proto-oncogene, EGL-43, is necessary for Notch-mediated cell fate specification and regulates cell invasion
Authors: Hwang Byung Joon , Meruelo Alejandro D. , Sternberg Paul W.
Published: January 2007

During C. elegans development, LIN-12 (Notch) signaling specifies the anchor cell (AC) and ventral uterine precursor cell (VU) fates from two equivalent pre-AC/pre-VU cells in the hermaphrodite gonad. Once specified, the AC induces patterned proliferation of vulva via expression of LIN-3 (EGF) and then invades into the vulval epithelium. Although these cellular processes are essential for the proper organogenesis of vulva and appear to be temporally regulated, the mechanisms that coordinate the processes are not well understood. We computationally identified egl-43 as a gene likely to be expressed in the pre-AC/pre-VU cells and the AC, based on the presence of an enhancer element similar to the one that transcribes lin-3 in the same cells. Genetic epistasis analyses reveal that egl-43 acts downstream of or parallel to lin-12 in AC/VU cell fate specification at an early developmental stage, and functions downstream of fos-1 as well as upstream of zmp-1 and him-4 to regulate AC invasion at a later developmental stage. Characterization of the egl-43regulatory region suggests that EGL-43 is a direct target of LIN-12 and HLH-2(E12/47), which is required for the specification of the VU fate during AC/VU specification. EGL-43 also regulates basement membrane breakdown during AC invasion through a FOS-1-responsive regulatory element that drives EGL-43 expression in the AC and VU cells at the later stage. Thus, egl-43integrates temporally distinct upstream regulatory events and helps program cell fate specification and cell invasion.
Dorsal-ventral midline signaling in the developingDrosophilaeye
Authors: Sato Atsushi , Tomlinson Andrew
Published: January 2007

Boundaries between different cell types play key roles in many developmental patterning processes. They can be established by various mechanisms, and signaling between the different cell types can occur in a number of ways. One mechanism of crossboundary signaling is controlled by the Notch (N)-modifying protein Fringe (Fng). At the Drosophila wing dorsal-ventral (D-V) border, the mechanism by which an Fng+-Fng- interface controls local N activation has been well characterized. A similar N-activating Fng+-Fng-interface has also been described at the D-V border of the fly eye, but the mechanisms that establish and regulate it are different from those in the wing. Here we describe the ventral role of the Sloppy-paired (Slp)transcription factor, and its interactions with dorsally expressed Iroquois(Iro) transcription factors in the regulation of signaling about the Fng+-Fng- interface in the developing eye. The two transcription factors are mutually repressive and initially abut at the D-V midline. However, N signaling at the interface downregulates Slp expression,and a gap opens between the two expression domains in which Serrate (Ser, an N ligand) is upregulated.
Caring for people with eating disorders: Factors associated with psychological distress and negative caregiving appraisals in carers of people with eating disorders
Authors: Whitney Jenna , Haigh Rachel , Weinman John , Treasure Janet
Published: January 2007

Objectives Carers of people with eating disorders (ED) have high levels of distress, but little is known about the contributing factors. The aim of this study was to examine predictors of carers' distress and caregiving appraisals using a model of caregiving adapted from the previous literature.

Design A cross‐sectional design was used.

Methods A sample of 115 individuals currently caring for someone with an ED participated in the study. Carers completed self‐report assessments of psychological distress (GHQ‐12; Goldberg & Williams, 1988), experience of caregiving (Szmukler et al., 1996), illness representations (IPQ‐SCV; Barrowclough, Lobban, Hatton, & Quinn, 2001) and caregiving needs (CaNAM; Haigh & Treasure, 2003). Simple and multiple hierarchical regressions were conducted.

Results Approximately 36% (39/109) of carers had scores on the GHQ which indicated mental health difficulties, with 17% (19/109) experiencing high psychological distress. A negative experience of caregiving was associated with carers' distress. The dependency of the individual with the ED and stigma associated with the illness were most highly predictive of carers' distress. Shorter illness duration, higher levels of needs (lower levels of support) and perceptions of high illness consequences contributed to greater negative caregiving appraisals. The belief that the illness was attributable to the sufferers' personality was related to fewer positive appraisals.

Conclusions Adjusting to the impact of a family member experiencing an ED is problematic, as suggested by the relationship between shorter illness duration and greater negative appraisals of caregiving. Interventions to help reduce dependency and alleviate stigma may help to decrease carers' distress.
Aggressivity: Cucumber vs. Amaranth
Authors: Berry Adrian D. , Stall William M. , Rathinasabapathi B. , Macdonald Gregory E. , Charudattan R.
Published: January 2007

A replacement series study was conducted to describe the aggressivity between cucumber, smooth pigweed, and livid amaranth. Cucumber was three times more competitive than smooth pigweed or livid amaranth, under the conditions of this study. However, there was equal competition and no antagonism between smooth pigweed and livid amaranth. Where cucumbers were planted in mixture with either of the two weeds, the relative yield total values were approximately 10 to 20% higher than the monocultures. Cucumber was a superior competitor when grown in mixture with smooth pigweed or livid amaranth, and the following aggressivity hierarchy exists: cucumber > livid amaranth = smooth pigweed. Results from the additive field study indicated that amaranth dry weights were significantly affected by smooth pigweed and livid amaranth density. Dry weight of amaranth was decreased by 48% at Gainesville and 25% at Live Oak, at 18 plants/m2. Despite differences between the Gainesville and Live Oak results, the dry weight data were similar for both smooth pigweed and livid amaranth at each location.
Weed Response to Mesotrione and Atrazine Applied Alone and in Combination Preemergence
Authors: Bollman Scott L. , Kells James J. , Penner Donald
Published: January 2007

Greenhouse studies were conducted to determine the response of velvetleaf, common cocklebur, and ivyleaf morningglory to mesotrione and atrazine applied PRE, and to characterize the nature of any interaction between mesotrione and atrazine. Sensitivity to mesotrione was as follows: velvetleaf > common cocklebur > ivyleaf morningglory. Sensitivity to atrazine was as follows: ivyleaf morningglory > common cocklebur > velvetleaf. Combinations of mesotrione and atrazine resulted in at least an additive interaction. The activity of mesotrione and atrazine applied in combination was generally additive for control of velvetleaf and ivyleaf morningglory but was synergistic for several rate combinations.
Interactions ofColletotrichum truncatumwith Herbicides for Control of Scentless Chamomile (Matricaria perforata)
Authors: Graham G. L. , Peng G. , Bailey K. L. , Holm F. A.
Published: January 2007

A host-specific fungusColletotrichum truncatumstrain 00-3B1 (Ct) was mixed with herbicides to improve the control of scentless chamomile, a noxious weed in western Canada. The compatibility of Ct conidia (spores) with herbicides was evaluated in vitro, and varying effects were observed with different products on spore germination. Clodinafop, glufosinate, MCPA, and 2,4-D ester were relatively benign and delayed the germination slightly, whereas dicamba, imazethapyr, metribuzin, and 2,4-D amine were noticeably more inhibitive. Bromoxynil, glyphosate, sethoxydim, and Merge®(spray adjuvant) were most inhibitive, showing >50% inhibition after 24 h. To determine potential synergy, Ct was applied at 7 × 106spores/ml in tank mixtures with selected herbicides at 1× and 0.1× registered rates under greenhouse conditions. Combining Ct with MCPA, 2,4-D ester, clopyralid, or metribuzin at 1× rate resulted in synergistic or additive interaction on scentless chamomile, increasing weed control significantly when compared to Ct or herbicides applied alone. Similar applications of Ct with imazethapyr, 2,4-D amine, dicamba, or glyphosate were antagonistic. Treatments with Ct plus 1× metribuzin killed scentless chamomile completely, whereas neither Ct nor the herbicide alone caused plant death, suggesting the value of this tank mixture.
Snap Bean (Phaseolus vulgaris) Tolerance to Halosulfuron PRE, POST, or PRE followed by POST
Authors: Silvey Brandy D. , Mitchem Wayne E. , Macrae Andrew W. , Monks David W.
Published: January 2007

A field experiment was conducted in 1996 and 1997 to determine snap bean tolerance to halosulfuron based on crop injury, height, and yield. Halosulfuron was applied preemergence (PRE), postemergence (POST), and sequentially PRE followed by (fb) POST at 35, 53, and 70 g ai/ha, respectively. For comparison, a hand-weeded check was included. When data were averaged across years and halosulfuron rates, halosulfuron PRE, POST, and PRE fb POST provided similar yellow nutsedge control (74 to 82%) at snap bean harvest. Halosulfuron PRE resulted in 4% snap bean injury at harvest. Similarly, halosulfuron PRE fb POST resulted in 5% injury, while halosulfuron POST caused the most damage at 8%. Snap bean height at harvest was reduced 14% with halosulfuron POST compared to the weed-free check, with only 5 and 6% reduction caused by halosulfuron PRE and PRE fb POST, respectively. Halosulfuron POST reduced yield 39% compared to the weed-free check, while the PRE and PRE fb POST application timings produced yield similar to the check. When averaged across years and halosulfuron application timings, an increase in halosulfuron rate had no effect on yellow nutsedge control or snap bean yield. A linear trend was found for snap bean injury and plant height at harvest with snap bean injury increasing with an increase in halosulfuron rate while snap bean plant height decreased with an increase in halosulfuron rate. Application of halosulfuron PRE is the safest means to control yellow nutsedge in snap bean in North Carolina.
Leaf-Waste Pellets as a Herbicide Carrier for Container-Grown Ornamental Plants
Authors: Samtani Jayesh B. , Kling Gary J. , Williams David J.
Published: January 2007

An organic herbicide carrier could help reduce misapplication and environmental pollution associated with spray application of herbicides. Pellets prepared from landscape leaves that were dried, ground, and pelletized were evaluated as a preemergence herbicide carrier for container-grown ornamental plants. Isoxaben, pendimethalin, and prodiamine at rates of 1.12, 2.25, and 2.25 kg ai/ha, respectively, with either water or landscape leaf-waste pellets as a carrier were applied to chrysanthemum ‘Lisa’, spirea ‘Neon Flash’, and wintercreeper ‘Coloratus’. Common groundsel, common purslane, and giant foxtail were seeded following herbicide application. Leaf-waste pellets as a carrier produced equivalent efficacy and phytotoxicity ratings to conventional spray application of pendimethalin and prodiamine on both chrysanthemum and wintercreeper. The leaf-waste pellets were not an effective carrier for the application of isoxaben alone. The pellets had inconsistent effects on spirea phytotoxicity and growth.
Weed Control, Yield, and Quality of Processing Tomato Production under Different Irrigation, Tillage, and Herbicide Systems
Authors: Sutton Kipp F. , Lanini W. Thomas , Mitchell Jefferey P. , Miyao Eugene M. , Shrestha Anil
Published: January 2007

A field experiment was conducted near Davis, CA, during the 2003 and 2004 summer growing seasons to compare weed control, yield, and fruit quality in different irrigation and tillage systems in processing tomato. Trial design was a subplots with the main plots as subsurface drip irrigation or furrow irrigation, subplots were standard tillage or conservation tillage, and sub-subplots were herbicide or no herbicide. The hypothesis was that subsurface drip irrigation could limit surface soil wetting and thus inhibit germination and growth of weeds equal to or better than standard tillage and/or herbicides. In both 2003 and 2004, weed densities in the subsurface drip irrigation treatments were over 98% lower than the levels in furrow irrigation treatments. In addition, weed densities were lower in the subsurface drip–conservation till–no herbicide treatment than in any of the furrow irrigation treatments, including the furrow irrigation–standard tillage–herbicide treatments. The time required for a hand-hoeing crew to remove weeds was 5 to 13 times greater in furrow irrigation treatments compared to subsurface drip irrigation treatments. Weed biomass on beds at tomato harvest was 10 to 14 times greater in the furrow systems as compared to the subsurface drip irrigation systems. These results demonstrate the effectiveness of subsurface drip irrigation in controlling weed germination and growth, compared to tillage or herbicide applications. Tomato yield was higher in the subsurface drip irrigation treatment compared to furrow irrigation in 2004. Herbicide treatment increased yield in 2004, but only in the furrow irrigation treatment in 2003. Fruit brix level was not related to treatment in 2003, but was lower in the subsurface drip irrigation plots in 2004. These results indicate that subsurface drip irrigation can reduce weed competition in conservation tillage systems, without requiring herbicide applications.
Red Rice (Oryza sativa) Plant Types Affect Growth, Coloration, and Flowering Characteristics of First- and Second-Generation Crosses with Rice
Authors: Gealy David R. , Yan Wengui , Rutger J. Neil
Published: January 2007

Red rice is a major weed of rice in the southern U.S. and can intercross with rice. Knowledge of the plant phenotypes from such crosses would be valuable for identification and management of these plants. Male-sterile long-grain tropical japonicas ‘Kaybonnet-1789’ and ‘Cypress-1819’ were crossed with two awned and two awnless U.S. red rice types. F1 plants produced pubescent leaves, red pericarp, and medium-grain seeds. Crosses involving awned LA3 and TX4 red rice produced F1 plants with reddish-purple basal leaf sheaths and usually flowered within the same time periods as the parents, whereas those involving awnless StgS red rice had green basal leaf sheaths, flowered much later than either parent, and produced awnless F1 and F2 offspring. Crosses involving awned red rice produced F1 plants with long awns and F2 plants with awns ranging in length from zero to that of red rice parents. F1 plants were taller than either parent and produced intermediate culm angles similar to red rice, whereas F2 plants had culms ranging from erect (like rice) to more open than red rice. Thus, true F1 hybrids from crosses between pure breeding (homozygous) rice and red rice can be positively identified by a combination of traits including pubescent leaves, medium-grain seeds with red pericarps, open plant types, and heights greater than the red rice parent. F1 hybrids may be awned or awnless, have purple or green stems, or have normal or delayed heading. F2 plants have a broad combination of phenotypic traits found in both parents and F1 hybrids.
Weed Management in Lettuce (Lactuca Sativa) with Preplant Irrigation
Authors: Shem-Tov Shachar , Fennimore Steve A. , Lanini W. Thomas
Published: January 2007

During dry weather, preplant irrigation of raised beds followed by shallow tillage to create a smooth planting bed is necessary to establish a good lettuce stand. Depletion of germinable weed seeds in the top 5 cm of soil by the sequence of preplant irrigation, followed 7 to 14 d later by shallow tillage to prepare a seedbed, reduces weed density in the subsequent crop. Preplant irrigation and tillage reduces weed density and, when used together with preplant herbicide, provides effective weed control in the cropping season. Preplant and in-crop weed densities resulting from furrow or sprinkler preplant irrigation, followed by shallow tillage and lettuce planting 7 or 14 d later, were compared with the no preplant irrigation control. During the 14-d preplant period, up to 127 weeds/m2emerged and were removed by shallow tillage before crop planting. Preplant irrigation and shallow tillage reduced in-crop weed density by up to 77% and reduced hand-weeding and crop-thinning time by up to 50% compared with the no preplant irrigation and no herbicide control. Delaying tillage for 14 d following preplant irrigation provided sufficient time for adequate heat unit accumulation (>120 growing degree days, base 10 C), allowing for many weeds to germinate and be killed by shallow tillage. However, 7 d between preplant irrigation and tillage resulted in less heat unit accumulation (<50 growing degree days, base 10 C) and less weed germination before tillage. Preplant irrigation together with pronamide at either 0.67 or 1.34 kg ai/ha reduced weed density compared with the no preplant irrigation. Effective use of preplant irrigation and preplant weed removal may increase the consistency of weed control with lower pronamide rates. Preplant irrigation followed by shallow tillage is an effective cultural practice to control in-crop weeds for conventional lettuce production.
A Mobile Field Robot with Vision-Based Detection of Volunteer Potato Plants in a Corn Crop
Authors: Van Evert Frits K. , Van Der Heijden Gerie W.A.M. , Lotz Lambertus A.P. , Polder Gerrit , Lamaker Arjan , De Jong Arjan , Kuyper Marjolijn C. , Groendijk Eltje J.K. , Neeteson Jacques J. , Van Der Zalm Ton
Published: January 2007

Volunteer potato is a perennial weed that is difficult to control in crop rotations. It was our objective to build a small, low-cost robot capable of detecting volunteer potato plants in a cornfield and thus demonstrate the potential for automatic control of this weed. We used an electric toy truck as the basis for our robot. We developed a fast row-recognition algorithm based on the Hough transform and implemented it using a webcam. We developed an algorithm that detects the presence of a potato plant based on a combination of size, shape, and color of the green elements in an image and implemented it using a second webcam. The robot was able to detect potatoes while navigating autonomously through experimental and commercial cornfields. In a first experiment, 319 out of 324 images were correctly classified (98.5%) as showing, or not showing, a potato plant. In a second experiment, 126 out of 141 images were correctly classified (89.4%). Detection of a potato plant resulted in an acoustic signal, but future robots may be fitted with weed control equipment, or they may use a global positioning system to map the presence of weed plants so that regular equipment can be used for control.
Texas Panicum (Panicum texanum) Control in Irrigated Field Corn (Zea mays) with Foramsulfuron, Glyphosate, Nicosulfuron, and Pendimethalin
Authors: Prostko Eric P. , Grey Timothy L. , Davis Jerry W.
Published: January 2007

Texas panicum is considered to be the most troublesome weed of field corn in the Southeast. Field trials were conducted in Georgia in 2003 and 2004 to compare pendimethalin, nicosulfuron, foramsulfuron, and glyphosate for Texas panicum control in irrigated field corn and to determine which herbicide provided the greatest economic returns. Pendimethalin applied early POST (EPOST), 10 to 12 d after planting (DAP), controlled Texas panicum less than 35% late in the season and resulted in reduced corn yield and net returns in 2004. Glyphosate applied sequentially POST at 21 to 24 DAP and again late POST (LPOST) at 35 to 38 DAP controlled Texas panicum 82 to 94% late in the season compared with 43 to 80% control by nicosulfuron and foramsulfuron applied POST. Texas panicum control, corn yield, and net returns were similar with glyphosate applied POST and LPOST at 0.53 or 1.1 kg ai/ha. Glyphosate applied POST and LPOST was more effective than glyphosate POST, but net returns were greater only in 2004.
Glyphosate Spray Drift Management with Drift-Reducing Nozzles and Adjuvants
Authors: Johnson Adam K. , Roeth Fred W. , Martin Alex R. , Klein Robert N.
Published: January 2007

Field experiments were conducted to evaluate the effect of five spray-nozzle types and three drift-control adjuvants (DCA) on glyphosate spray drift. The extended-range (XR) flat-fan nozzle at 280 kPa was used as the standard comparison. DCAs were evaluated for drift reduction with the use of the XR and air-induction (AI) nozzles. Wind speed ranged from 1.3 to 9.4 m/s (3 to 21 mph). Lethal drift (DL) and injury drift (DI) were determined by downwind visual observation of grain sorghum response. Drift distances were measured from the spray swath edge. The Turbo FloodJet and AI nozzles reduced DLdistance by 34%. All four drift-reducing (DR) nozzles reduced DIdistance by 22 to 32%. Reducing the pressure of the XR flat-fan nozzle from 280 to 140 kPa did not reduce DLor DIdistance. When applied through AI nozzles, each DCA increased droplet volume diameter, one DCA reduced DIdistance and none reduced DLdistance when applied through XR tips. The DCAs did not affect DLor DIdistance.
Shear-resistant design of biaxially loaded RC beams
Authors: Mark P.
Published: January 2007

A method is derived to design reinforced concrete beams with rectangular cross-sections and usual side-aligned stirrups against biaxial shear forces. It is based on spatial strut and tie models that describe the increase of stirrup and concrete stresses occurring, if resultant shear forces act inclined to the principal axes of the cross-section. Interpolation factors model these increases in dependence upon related inclinations. They generalise the resistances of the tensile and of the compressive shear strut, as it is exemplarily shown for the formulae of the ‘Standard Method’ in Eurocode 2. The method is verified with experimental and numerical data and applied to a typical example. A design by components—separately treating the two principal directions—does not only misjudge the actual nonlinear physical behaviour, it also evidently overestimates resistances and makes designs unsafe.
Design method for slender columns subjected to biaxial bending based on second-order eccentricity
Authors: Bonet J. L. , Romero M. L. , Fernandez M. A. , Miguel P. F.
Published: January 2007

The present paper proposes a simplified method to design slender rectangular reinforced concrete columns with doubly symmetric reinforcement. The proposal is based on the computation of the second-order eccentricity method from the Eurocode 2 (December 2004). It is valid for columns subjected to combined axial loads and either uniaxial or biaxial bending, short-time and sustained loads, and also for normal- and high-strength concretes. It is only suitable for columns with equal effective buckling lengths in the two principal bending planes. It is an extension for biaxial bending of the column-model method. The current paper is the second part of a research study conducted by the current authors. The method was compared with 371 experimental tests from the literature and a high degree of accuracy was obtained. Precision for sustained loads and biaxial bending was improved in comparison with the method proposed by Eurocode 2 (December 2004). The method allows slender reinforced concrete columns to be both checked and designed with sufficient accuracy for engineering practice.
Dynamic behaviour of concrete in biaxial compression
Authors: Yan D. , Lin G.
Published: January 2007

Thoroughly understanding the behaviour of concrete in dynamic loading is an issue of great significance in civil engineering. However, our knowledge is limited by a lack of dynamic experiment database, especially that collected by dynamic multiaxial tests. Biaxial compressive experiments on 100 mm concrete cubes were performed using a servo-hydraulic multiaxial testing system designed and manufactured at Dalian University of Technology, China. The specimens were loaded in biaxial stress states. The lateral pressure was maintained at a fixed proportion to the axial load, with the stress ratios of 0:1, 0·25:1, 0·5:1, 0·75:1, 1:1 respectively. The strain rate varied from 10−5/s to 10−2/s. From the test results it is revealed that the dynamic strength increases as the strain rate increases, while the damage pattern and the ultimate strength are closely related to the magnitude of lateral pressure exerted on the specimen. The shapes of stress–strain curves of the specimens at different strain rates are similar to each other. A unified formula is proposed to characterise both the effect of strain rate and the effect of stress ratio on the ultimate strength of concrete in biaxial stress states.
Long-term behaviour of square concrete-filled steel tubular columns under axial service loads
Authors: Kwon S.-H. , Kim T.-H. , Kim Y.-Y. , Kim J.-K.
Published: January 2007

This paper presents experimental and analytical studies on the long-term behaviour of rectangular concrete-filled steel tubular (CFT) columns under central axial loading. Four loading cases are considered in this study: (a) a load applied simultaneously on both the inner concrete and steel tube (SCE); (b) a load applied only on the inner core concrete (CE); (c) a load applied on the steel tube and three quarters of the inner concrete (SCQ); and (d) a load applied on the steel tube and half of the inner concrete (SCH). The last two loading cases (SCQ and SCH) simulate a diaphragm installed in the steel tube. Specimens measuring 600 mm in length were tested for the first two loading cases (SCE and CE), and specimens of three different lengths, 600, 900 and 1200 mm, were tested for the last two loading cases in order to investigate the effect of the diaphragm size and the length of the specimen on the long-term behaviour of rectangular CFT columns. In addition to the experimental study, three-dimensional finite element models for each specimen were established and verified from a comparison of the test data and the analysis results. From the test and analysis results, a number of conclusions can be drawn. The magnitude of long-term deformation of a CFT column with a diaphragm that covers more than a half of the cross-sectional area of the inner concrete is identical with that of a column under a load applied simultaneously on the entire section of the steel tube and the inner concrete. The diaphragm confines the lateral deformation of the end surface of the column, and its influence range is limited only to the end part of the column, meaning it is limited only from the surface to a depth as long as the width of the CFT column. The confinement effect and stress variation along the longitudinal axis do not occur except in the influence range of the diaphragm. In the case of loading only at the inner concrete, the inner concrete is confined at the corner by the steel tube, and the slip between the inner concrete and the steel tube increases over time.
Lateral position of traffic negotiating horizontal bends
Authors: Gunay B. , Woodward D.
Published: January 2007

The lateral position of vehicles at horizontal curves and roundabout circles has been studied, and it has been observed that drivers tend to straighten their travel path as much as possible when negotiating these bends in a corner-cutting fashion. In addition to skid resistance loss, this behaviour results in the early scuffing and removal of road markings. Preliminary data were collected in Northern Ireland at eight different sites over 15 lanes in total. It was found that the expected geometrical location of the wheel path is not the same as the actual observed location at certain sections of highways. On horizontal curves, the most travelled wheel path is shifted towards the convex side of the curve, and this shift increases with decreasing radius, such as at roundabouts, where it reaches a maximum displacement. This shift was about 140 cm in the outer circles of roundabouts and about 60 cm in the inner circles. For horizontal curves the figure was in the region of 30–40 cm.
Traffic-flow impact of toll booths on M50 motorway, Dublin
Authors: Rogers M. , Darcy S.
Published: January 2007

The M50 was opened to traffic in 1990. In the intervening years the daily volumes have increased dramatically, and are predicted to exceed 90 000 by 2006. In recent times the motorway has been repeatedly congested, both during weekdays and at weekends. There is at present a perception among motorists, reinforced by political and media comment, that existing delays and congestion along the M50 are caused primarily by the operation of the toll booths at the West-Link toll bridge, located at the centre point of Dublin's M50 C-Ring motorway. This paper examines the validity of this assertion, and highlights other capacity constraints within the link that may provide more plausible and technically robust explanations for the delays experienced by motorists in the vicinity of the toll plaza.
Improving a gypsum sand roadbed soil by increased compaction
Authors: Razouki S. S. , Ibrahim A. N.
Published: January 2007

A silty sand of the SM group according to the Unified Soil Classification System and of the A-1-b group according to the American Association of State Highway and Transportation Officials (AASHTO) soil classification system, with about 28% gypsum content, was tested in the laboratory for California Bearing Ratio (CBR) under four different compaction efforts. Twenty-four pairs of CBR soil samples were completed at the optimum moisture content derived from a modified AASHTO compaction test. To achieve different compaction efforts, four groups, each of six pairs of samples, were compacted using 10, 30, 50 and 70 blows per layer respectively. The individual pairs in each group were then soaked for different periods of time—4, 7, 15, 30, 60 and 120 days—while subject to a surcharge load of 40 lbf (178 N). The CBR test results show the significant effect of compaction effort on CBR value. An increase in soaking period causes a significant decrease in the CBR for each degree of compaction effort. Samples made under low compaction efforts are affected more by soaking than those made under high compaction efforts.
Novel pixel design for high‐resolution AMOLED displays with a shadow mask
Authors: Lih Jiin‐Jou , Chao Ching‐Ian , Lee Chung‐Chun
Published: January 2007

Abstract— The bottlenecks in achieving high resolution for active‐matrix OLED (AMOLED) displays based on currently available manufacturing processes were evaluated and compared. The use of a shadow mask has proven to be viable for mass production, but the fabrication of high‐precision shadow masks becomes very difficult when the resolution exceeds 180 ppi. The latest breakthrough in increasing display resolution is presented. Without an increase in cost, the limitations of the conventional shadow‐mask process using novel subpixel designs have been successfully overcome. A high resolution reaching of 270 ppi has been successfully demonstrated on a 3‐in. VGA‐format AMOLED display, fabricated by using a shadow mask with a much lower resolution of 135 ppi. This innovative pixel design opens up the possibilities of manufacturing high‐resolution displays using a relatively low‐resolution shadow mask.
Advanced IPS technology for mobile applications
Authors: Aoki N. , Komura S. , Furuhashi T. , Adachi M. , Itou O. , Miyazawa T. , Ohkura M.
Published: January 2007

Abstract— In‐plane‐switching LCD (IPS‐LCD) technologies originally developed for LCD monitors and TV applications are applied to mobile applications. Advantages of the IPS mode over other optical modes for mobile applications are quantitatively clarified. The panel achieves stable color reproduction and chromaticity in the viewing‐angle range for mobile displays. Superiority of the IPS mode over other optical modes is discussed also from the viewpoints of stability in chromaticity during the brightness change and the driving power consumption. A transflective IPS mode with good performance is accomplished by the use of a proper optical design. A new structure, IPS‐Pro, which enables sunlight readability by increasing the transmittance, i.e., the brightness of the panel, without additional cost and power consumption in contrast to additional fabrication processes required to fabricate the transflective mode is realized. Furthermore, to improve the users' convenience, an automatic luminance control system and a controllable viewing‐angle device are developed. The panels developed fulfill the market requirements of increasing the function and performance variations and will be the most appropriate ones to be applied to mobile appliances, such as cellular phones, digital still cameras, music players, GPS, mobile TV sets, etc.
A novel spacer‐free panel structure and glass for FEDs
Authors: Sugawara Tsunehiko , Murakami Takahiro , Kuroki Yuichi , Ueki Mikio , Naraki Takeshi , Kato Yasumasa , Kanasugi Satoshi
Published: January 2007

Abstract— A new design for an FED envelope, composed of box‐shaped front glass, sheet‐like rear glass, and metal members, has been devised. This design structure is effective in reducing tensile stress induced by vacuum at the sealing points. Also, a new glass composition, a new physical tempering method, and a lead‐free hermetic sealing material have been developed. As a result, a novel lightweight spacer‐free panel structure for FEDs has been developed by integrating these new technologies. It will assist in maximizing the essential advantages of FED such as high image quality, high reliability, and low cost.
Making the best of legacy video on modern displays
Authors: Zhao M. , Bosma M. , De Haan G.
Published: January 2007

Abstract—The recent revolution in display technology enables bright high‐resolution displays, thereby removing one of the bottlenecks in video quality. How to profit from HD flat‐panel displays when watching legacy SD‐video material will be discussed. An overview of resolution up‐conversion techniques will be presented, including an objective (MSE‐scores) and a subjective assessment. Screenshots are also included to illustrate the quality of the algorithms.
A psychophysical study of improvements in motion‐image quality by using high frame rates
Authors: Kuroki Y. , Nishi T. , Kobayashi S. , Oyaizu H. , Yoshimura S.
Published: January 2007

Abstract— The ideal frame rate for the highest motion‐image quality with respect to blur and jerkiness is presented. In order to determine the requirements for avoiding these impairments, motion images from a high‐speed camera and computer graphics were combined with a high‐speed display to perform a psychophysical evaluation. The camera, operating at 1000 fps, and image processing were used to simulate various frame rates and shutter speeds, and a 480‐Hz CRT display was used to present motion images simulating various frame rates and time characteristics of the display. Subjects were asked to evaluate the difference in quality between motion images at various frame rates. A frame rate of 480 fps was chosen to be an appropriate reference frame rate that, as a first estimation, enables coverage up to the human‐dynamic‐resolution (HDR) limit based on another experiment using real moving charts. The results show that a frame rate of 120 fps provides good improvement compared to that of 60 fps, and that the maximum improvement beyond which evaluation is saturated is found at about 240 fps for representative standard‐resolution natural images.
Use of Ecosystem Information to Improve Soil Organic Carbon Mapping of a Mediterranean Island
Authors: D'Acqui Luigi P. , Santi Carolina A. , Maselli Fabio
Published: January 2007

Detailed maps of soil C are needed to guide sustainable soil uses and management decisions. The quality of soil C maps of Italian Mediterranean areas may be improved and the sampling density reduced using secondary data related to the nature of the ecosystem. The current study was conducted to determine: (i) the improvements obtainable in mapping soil C over a Mediterranean island by using ecosystem features and (ii) the effect of different sampling densities on the map accuracy. This work relied on field sampling (n= 164) of soil properties measured over the island of Pianosa (Central Italy). Statistical analysis assessing the relationship between soil properties and ecosystem features revealed that the conceptual model of ecosystems defined on the basis of environmental features such as vegetation cover, land use, and soil type was mainly related to the variation of soil organic carbon (OC) content and to the type of Mediterranean environment. The distribution of ecosystems was used to improve the accuracy of soil OC maps obtainable by a simple interpolation approach (ordinary kriging). Substantial improvement was obtained by: (i) stratification into ecosystem types and (ii) applying locally calibrated regressions to satellite imagery that introduced both inter‐ecosystem and intra‐ecosystem information linked to vegetation features. This study showed that interpolation methods using information on ecosystem distribution can produce accurate maps of soil OC in Mediterranean environments, mostly because of the linkage between soil OC and vegetation types, which are spatially fragmented and heterogeneous.