bluuebunny/crossref_metadata_2025 huggingface dataset:
Attributional Styles, Self-Esteem, and Just World Belief of Victims of Bullying in Dutch Organizations
Authors: Steensma Herman , Van Dijke Richard
Published: April 2007

Large-scale surveys in Europe document that some 8–15% of European workers are subjected to intimidation and bullying. Victims of severe bullying in Dutch organizations ( N = 21) and non-victims ( N = 30) filled out questionnaires. As predicted, victims had a lower Just World Belief, and lower self-esteem than non-victims. Moreover, victims attached higher importance to negative situations than non-victims do. The two groups demonstrated only minor differences in their attributions of internal, and stable causes to negative events. However, victims of bullying attributed causes of bullying significantly more often to specific aspects of situations. In the discussion it is suggested that in future research a distinction should be made between subgroups of victims.
San Sebastián: The Social and Political Effects of Sugar Mill Closure in Mexico
Authors: Powell Kathy
Published: April 2007

Mexico's sugar mills face an uncertain future: the closure of San Sebastián may well presage others if the climate for sugar production on national and international levels does not improve. While the continued squeezing of small cane producers reflects processes affecting peasant agriculture generally in Mexico, and indeed beyond, the fate of the mill workers made redundant when the mill closed similarly mirrors broad tendencies in labor in both the developed and developing world under neoliberalism. Former workers fell back upon personal, family, and community resources by migrating to the U.S. or locally reconstructing livelihoods characterized by a reduction in income, security, and access to social benefits. This article reports on the impact of the mill closure on the livelihoods of former mill worker families in the community of San Sebastián and offers some observations on their responses to the situation.
Orality and the Process of Writing
Authors: Van Woerkum C. M. J.
Published: April 2007

The aim of this article is to show that a better awareness of the relationship between written and spoken communication can help the writer to improve his/her effectiveness. The focus will be on written texts that precede (formal and informal) discussions. The analysis will start with a description of the differences between orality and literacy. We shall deal with the functions of orality-based texts for the readers. Then we shall move to the writing process and explain how orality can find a place in this process, how it can be linked to creativity, and how it affects the way we plan the writing process. An oral way of writing is related to an important feature of speaking, namely fluency; but it also means a specific receiver orientation, dynamic rather than static and social rather than individual. Computer mediated communication could influence a more oral approach to written texts.
The Boston-Area Haswic Research Circle: An Innovative Participatory Method for Coloring in the Picture of a Special Work Environment
Authors: Moir Susan , Azaroff Lenore S.
Published: April 2007

Recent qualitative studies have investigated some of the hazards affecting women in non-traditional trades such as construction. However, one-time interactions among researcher participants, and between researchers and participants, in standard settings such as focus groups and interviews, cannot provide the time, space, and relationships to fully explore tradeswomen's in-depth knowledge of their work environment. This study applied a Scandinavian method called the Research Circle to convene a group of experienced women construction workers repeatedly over a period of two years so they could collaborate with researchers in explaining workplace issues. The results both validated and expanded upon previous findings about health and safety for women in construction, including gender discrimination, lack of access to sanitary facilities, retaliation for reporting hazards and injuries, and inadequate training and equipment. Especially important, findings illustrate some of the complex hierarchical social structures involved in both female and male construction workers responding to hazardous conditions.
Habitat Selection by American Martens in Coastal California
Authors: SLAUSON KEITH M. , ZIELINSKI WILLIAM J. , HAYES JOHN P.
Published: April 2007

ABSTRACTWe investigated habitat selection using single‐ and mixed‐scale modeling at 2 spatial scales, stand and home range, by the only known population of American martens (Martes americana) remaining in the historical range of the Humboldt subspecies (M. a. humboldtensis) in California, USA. During 2000 and 2001, we sampled a 12 times 14 grid with 2‐km spacing, using 2 sooted track plates at each grid point. We detected martens at 26 of the 159 grid points. We used resource selection probability functions and an information‐theoretic method to model habitat at detection locations. At the stand scale, martens selected conifer‐dominated stands with dense, spatially extensive shrub cover (x̄ = 74% cover, SE = 4) in the oldest developmental stage. At the home‐range scale, martens selected the largest available patches (x̄ = 181 ha, SE = 14) of old‐growth, old‐growth and late‐mature, or serpentine habitat. Mixed‐scale models revealed that habitat characteristics from both scales best explained marten occurrence compared to one scale alone. Dense, spatially extensive shrub cover is a key habitat element for martens in coastal forests. Dense shrubs provide refuge from predators, cover for prey, and may also deter larger‐bodied competitors. Managers can increase the likelihood of marten population persistence and encourage expansion in coastal forests by maintaining and restoring late‐mature and old‐growth, conifer‐dominated forests with dense shrub cover in large, contiguous patches.
Influence of Population Reduction on Predator Home Range Size and Spatial Overlap
Authors: FREY S. NICOLE , CONOVER MICHAEL R.
Published: April 2007

ABSTRACTThe increasing populations of red foxes (Vulpes vulpes), raccoons (Procyon lotor), and striped skunks (Mephitis mephitis) in the Intermountain West have contributed to low waterfowl recruitment in recent decades. This effect prompted the need for predator removal at many waterfowl refuges, such as the Bear River Migratory Bird Refuge (BRMBR) in the Great Salt Lake ecosystem. Our study examined the effects of the removal of predatory mammals at the BRMBR on the home range size and spatial overlap of the remaining populations of red foxes, raccoons, and striped skunks. The removal of predators through traps, snares, and night‐shooting created a lower predator population during the predators' rearing and dispersal seasons. Predator removal did not result in a change of home range size for red foxes, raccoons, or striped skunks. In all species, home ranges were of similar size during the rearing and dispersal seasons and there were no differences among sexes. After predator removal, the proportion of a home range that overlapped with that of another conspecific decreased in foxes but increased in raccoons. However, predator removal did not change the proportion of inter‐specific home range overlap between foxes and raccoons. These findings indicate that home range sizes of these mammalian predators were not constrained by their population densities prior to predator management. In this situation, predator control may be only temporarily successful in reducing predator populations. Managers may achieve more permanent reduction in predator population by decreasing food and shelter resources, thereby reducing the carrying capacity of the landscape.
Size Bias in Visual Searches and Trapping of Brown Treesnakes on Guam
Authors: RODDA GORDON H. , SAVIDGE JULIE A. , TYRRELL CLAUDINE L. , CHRISTY MICHELLE T. , ELLINGSON AARON R.
Published: April 2007

ABSTRACT The accidental introduction of the brown treesnake (BTS; Boiga irregularis) to the island of Guam after World War II set off a chain of bird, bat, and lizard extirpations. Fortunately, many of the eliminated species have the potential to be restored following population reduction or eradication of the snake. The primary operational tool for population reduction is an effective snake trap, but areas subjected to long‐term trapping continue to support BTS, suggesting that some adult snakes are refractory to trapping. We closed a 5‐ha area to BTS emigration and immigration and surveyed the population using trapping and visual surveys to determine whether a refractory stratum of adult snakes existed and if trapping was effective for snakes of all sizes. Our surveys included 101 trapping occasions and 109 visual surveys over 309 days, resulting in 2,522 detections of 122 individuals. We detected 44 of 45 supplemented snakes by this intensive sampling effort, which also revealed that trapping was fully effective for snakes >900 mm in snout—vent length (SVL), partially effective for snakes 700–900 mm SVL, and totally ineffective for smaller juveniles (350–700 mm SVL). Visual searching was effective for snakes of all sizes. As BTS mature at approximately 950‐1, 050 mm SVL, continuous trapping should suffice to eliminate recruitment in the absence of immigration. Immigration or inadequate effort is most likely responsible for the persistence of BTS in areas subject to long‐term trapping. Thus, current efforts to capture trap‐refractory adult snakes with alternate control tools are less likely to be successful than immigration barriers alone or in combination with elevated capture effort.
Fruit Production in Mature and Recently Regenerated Forests of the Appalachians
Authors: GREENBERG CATHRYN H. , LEVEY DOUGLAS J. , LOFTIS DAVID L.
Published: April 2007

ABSTRACT Fleshy fruit is a key food resource for both game and nongame wildlife, and it may be especially important for migratory birds during fall and for resident birds and mammals during winter. Land managers need to know how land uses affect the quantities and species of fruit produced in different forest types and how fruit production varies seasonally and as young stands mature. During June 1999‐April 2004, we quantified fleshy fruit abundance monthly in 31 0.1‐ha plots in 2 silvicultural treatments: 1) young 2‐age stands with low basal area retention, created by shelterwood‐with‐reserves regeneration cuts (R; harvested 1998–1999); and 2) uncut mature closed‐canopy stands (M) in 2 common southern Appalachian, USA, forest types (upland hardwood and cove hardwood [CH] forests). Over the 5‐year study period, total dry pulp biomass production was low and relatively constant in both M forest types (x̄ = 0.5‐2.0 kg/ha). In contrast, fruit production increased each year in R, and it was 5.0 to 19.6 times greater in R than in M stands beginning 3–5 years postharvest. Two disturbance‐associated species, pokeweed (Phytolacca americana) and blackberry (Rubus allegheniensis), produced a large proportion of fruit in R but showed different patterns of establishment and decline. Huckleberry (Gaylussacia ursina) recovered rapidly after harvest and was a major producer in both silvicultural treatments and forest types each year. Several herbaceous species that are not associated with disturbance produced more fruit in CHR. Few species produced more fruit in M than in R. Fruit production by most tree species was similar between R and M, due to fruiting by stump sprouts in R within 1–3 years postharvest. Fruit availability was highest during summer and early fall. American holly (Ilex opaca), sumac (Rhus spp.), and greenbriar (Smilax spp.) retained fruit during winter months but were patchy in distribution. In the southern Appalachians, young recently regenerated stands provide abundant fruit compared to mature forest stands and represent an important source of food for wildlife for several years after harvest. Fruit availability differs temporally and spatially because of differences in species composition, fruiting phenology, and the dynamic process of colonization and recovery in recently harvested stands. Land managers could enhance fruit availability for many game and nongame species by creating or maintaining young stands within forests.
Northern Bobwhites and Postfire Succession
Authors: RANSOM DEAN , SCHULZ GERRAL G.
Published: April 2007

ABSTRACTOur study evaluated the effects of prescribed fire on northern bobwhites (Colinus virginianus) occupying native rangelands in Rolling Plains of Texas, USA, during 2002 and 2003. Prescribed fires were conducted during February of 1996, 1998, and 2000; pastures with no recent treatment history served as controls. We quantified bobwhite densities from line transects using distance sampling. We used a repeated‐measures analysis of variance to test for treatment‐year differences in bobwhite densities. We measured postfire herbaceous and woody vegetation attributes and evaluated vegetation relationships to bobwhite density using simple linear regression. We found significant between‐year differences in fall bobwhite densities (F= 13.05, df = 3,P= 0.036) but no differences among treatments or controls. Fall bobwhite densities were inversely related to visual obstruction (r2= 0.179, df = 15,P= 0.058) and positively associated with increasing heterogeneity of grass cover (r2= 0.416, df = 15,P= 0.004). Our results suggest prescribed fire at large spatial scales may be a neutral practice for managing bobwhite habitat on semiarid rangelands.
Modeling the Western Arctic Caribou Herd During a Positive Growth Phase: Potential Effects of Wolves and Radiocollars
Authors: HASKELL SHAWN P. , BALLARD WARREN B.
Published: April 2007

ABSTRACT Population modeling exercises can lead to both expected and unexpected results useful for wildlife research and management, even though inferences must often be qualitative, given underlying assumptions. Our main objective was to use empirical data on wolf (Canis lupus) kill rates and growth of the Western Arctic caribou (Rangifer tarandus) herd (WAH) of Alaska, USA, to assess the potential for predator regulation. We used available data and published literature to construct a deterministic density‐dependent population model fitted to trends of the WAH from 1976 through 2003. By increasing wolf densities in the baseline model, we failed to reject the hypothesis that wolves at a density of 6.5 wolves per 1,000 km2 could regulate a caribou herd at a density of 0.4 caribou per km2. In addition, our model may be conservative by underestimating the regulatory potential of wolves. We suggest that this relatively simple predator‐preysystem shows signs of a predation—food 2‐state model. Elasticities from matrix models may be deceiving. Although herd growth is most sensitive to changes in adult female survival, survival of younger cohorts may be more easily influenced by natural conditions or management action. Management of the WAH near maximum sustained yield may not be attainable if desired, but modeling exercises such as this elucidate options. In conducting this research, we also discovered by Monte Carlo simulation that survival and productivity data from radiocollared females and calves were negatively biased and failed to predict herd growth. Thus, researchers should consider potential effects of neck collars on vital rates of female tundra caribou and concomitant offspring when using sample data to model population dynamics or test hypotheses.
Menopausal status and factors affecting cessation of menses in the region of Bonn, Germany
Authors: Pierl C. , Rabstein S. , Harth V. , Brüning T. , Brauch H. , Fischer H. , Hamann U. , Justenhoven C. , Ko Y. , Pesch B.
Published: April 2007

Because of the high prevalence of hormone use and reproductive surgeries in Western women natural menopause is a less frequent condition. Our aim was to examine the influences of hormonal and other factors on timing of cessation of menses. We analysed population controls of a German case-control study on breast cancer risks. The sample comprised N=829 women without hysterectomy or bilateral oophorectomy. We estimated the risk for the occurrence of last menses by Cox proportional hazard modelling. For calculating hazard rate ratios (HRR) and 95% confidence intervals (CI) women with menstrual cycles up to one year before interview were censored at that age. Median age at cessation of menses was 50 years (inter-quartile range 47–53 years). A significant later cessation of menses resulted from oral contraceptive use (HRR 0.74, 95% CI 0.59–0.93 for up to 10 years), and hormone therapy use until last menses (HRR 0.57, 95% CI 0.47–0.70). Also, thyroidal medications were associated with a delayed cessation of menses (HRR 0.64, 95% CI 0.42–0.96 for more than 10 years of use). Smoking until at least two years before last menses and allergies revealed an earlier cessation of bleedings (HRR 1.50, 95% CI 1.22–1.83 and HRR 1.28, 95% CI 1.07–1.53 respectively). Natural menopause is difficult to determine. Factors affecting the ovaries or the endocrine system can modulate timing of menopause. Endocrine biomarkers should be additionally taken into account when defining menopausal status.
Late‐onset cobalamin‐C disorder: A challenging diagnosis
Authors: Ben‐Omran Tawfeg I. , Wong Hubert , Blaser Susan , Feigenbaum Annette
Published: April 2007

Cobalamin‐C (cblC) disease is a rare autosomal recessive disorder due to defective intracellular cobalamin metabolism. There are few (13) reported patients of the late‐onset presentation of cblC disease with paucity of detailed clinical descriptions. This results in this condition being easily missed. In this report, we describe clinical and biochemical findings of two unrelated patients with late‐onset cblC disease who presented with neuropsychiatric symptoms. Serial MRI images are provided for one of these patients. Presumptive diagnosis was made with urine and plasma biochemical markers and confirmed with fibroblast analysis. These patients illustrate the challenging diagnosis of this disease and also report on the rare associated findings of vasculopathy and mitochondrial respiratory chain dysfunction. Mutation analysis of the MMACHC gene showed that both patients were homozygous for 394C → T which suggests a founder effect. © 2007 Wiley‐Liss, Inc.
Laminectomies and achondroplasia: Does body mass index influence surgical outcomes?
Authors: Ain Michael C. , Chang Tai‐Li , Schkrohowsky Joshua G.
Published: April 2007

Obesity is a widespread and potentially serious health problem in individuals with achondroplasia. In addition to obesity, such individuals commonly experience lumbar spinal stenosis. Although laminectomies have long been the method of choice for thorough lumbar decompression, to the best of our knowledge, the relationship between body mass index (BMI) and surgical outcomes after laminectomy in patients with achondroplasia has not been investigated in a large patient population. Through a retrospective medical record review of the initial laminectomies of all individuals with achondroplasia at our institution for whom adequate records were available, we evaluated the influence of BMI on surgical outcomes after laminectomy via four criteria: (1) change in Rankin score; (2) change in walking distance; (3) intra‐operative and post‐operative complications; and (4) need for subsequent revision laminectomies. The 49 individuals (mean BMI: 31.5 kg/m2 at the time of laminectomy) were stratified into the standard BMI categories: normal (<25 kg/m2), overweight (25–29.9 kg/m2), obese Class I (30–34.9 kg/m2), and a combined obese Class II (35–39.9 kg/m2) and obese Class III (>40 kg/m2). Our analysis indicated that there was no statistical difference between these groups in terms of the four criteria. When the study group was categorized into non‐obese (normal weight and overweight) and obese (obese Classes I and II/III) groups, there was also no statistically significant improvement difference in terms the same four criteria. Our data suggest that obesity does not pose additional risks to laminectomy in individuals with achondroplasia. © 2007 Wiley‐Liss, Inc.
Differential effects of trisomy on brain shape and volume in related aneuploid mouse models
Authors: Aldridge Kristina , Reeves Roger H. , Olson Lisa E. , Richtsmeier Joan T.
Published: April 2007

Down syndrome (DS) results from inheritance of three copies of human chromosome 21 (Hsa21). Individuals with DS have a significantly smaller brain size overall and a disproportionately small cerebellum. The small cerebellum is seen in Ts65Dn mice, which have segmental trisomy for orthologs of about half the genes on Hsa21 and provide a genetic model for DS. While small cerebellar size is well‐established in mouse and humans, much less is known about the shape of the brain in trisomy. Here we conduct a morphometric analysis of the whole brain and cerebellum in Ts65Dn mice and show that the differences with euploid littermates are largely a function of volume and not of shape. This is not the case in two aneuploid mouse models that have fewer genes orthologous to Hsa21 than Ts65Dn. Ts1Rhr is trisomic for genes corresponding to the so‐called Down syndrome critical region (DSCR), which was purported to contain a dosage sensitive gene or genes responsible for many phenotypes of DS. Ms1Rhr is monosomic for the same segment. These models show effects on cerebellum and overall brain that are different from each other and from Ts65Dn. These models can help to identify the contributions of genes from different regions of the chromosome on this and other aspects of brain development in trisomy. © 2007 Wiley‐Liss, Inc.
Gas sorption in semicrystalline rubbery polymers revisited
Authors: López‐González Mar , Compañ Vicente , Riande Evaristo
Published: April 2007

This work reports the solubility of carbon dioxide, ethylene and propylene in low density polyethylenes with densities lying in the range 0.870–0.940 g/cm3. The sorption behavior is studied as a function of the crystallinity in terms of the Flory‐Huggins theory of polymer solutions. For each gas, both the Henry's solubility constant referred to the amorphous phase of the films and its temperature dependence do not change significantly with the crystallinity of the LDPE films. The enthalpic polymer–gas interaction changes with the nature of the gases, but not with the crystallinity of the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Cure characteristics, morphology, and mechanical properties of ethylene–propylene–diene–monomer rubber/acrylonitrile butadiene rubber blends
Authors: Manoj K. C. , Unnikrishnan G.
Published: April 2007

Blends based on ethylene–propylene–diene monomer rubber (EPDM) and acrylonitrile butadiene rubber (NBR) was prepared. Sulfur was used as the vulcanizing agent. The effects of blend ratio on the cure characteristics and mechanical properties, such as stress–strain behavior, tensile strength, elongation at break, hardness, rebound resilience, and abrasion resistance have been investigated. Tensile and tear strength showed synergism for the blend containing 30% of NBR, which has been explained in terms of morphology of the blends attested by scanning electron micrographs. A relatively cocontinuous morphology was observed for 70 : 30, EPDM/NBR blend system. The experimental results have been compared with the relevant theoretical models. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Amphiphilic block copolymers based on methoxy poly(ethylene glycol) and either crystalline or amorphous poly(caprolactone‐b‐lactide): Synthesis, solid‐state and aqueous solution characterizations
Authors: Zhang Jie , Wang Li‐Qun , Wang Hongjun , Tu Kehua , Liu Li
Published: April 2007

Amphiphilic block copolymers consisting of methoxy poly(ethylene glycol) (mPEG) and either crystalline poly(caprolactone‐b‐L‐lactide) [P(CL‐LLA)]or amorphous poly(caprolactone‐b‐D,L‐lactide) [P(CL‐DLLA)], respectively, were prepared under mild conditions using dicyclohexylcarbodiimide as coupling agent. Micelles were formed from the resultant copolymers with predetermined hydrophobic and hydrophilic blocks in water by dialysis method. The composition and structure of the copolymers were characterized by1H‐NMR,13C‐NMR, and GPC measurements. Differential scanning calorimetry analysis revealed that the crystallization behavior of P(CL‐LLA) block is affected significantly by the molecular weight of the conjugated mPEG block, and the glass transition temperature (Tg) of P(CL‐DLLA) block is depressed by the existence of mPEG moiety in the block copolymer. The crystallization behavior was also characterized by the technique of polarized light microscopy. The hydrodynamic diameter and size distribution of micelles were determined by particle size measurements. Transmission electron microscopy images showed that P(CL‐LLA)‐b‐mPEG block copolymer self‐aggregated into thread‐like shape in water, whereas P(CL‐DLLA)‐b‐mPEG adopted a classical spherical shape. It is suggested that both the high enthalpy of crystallization and hydrophobicity of P(CL‐LLA) core‐forming blocks would be responsible for the thread‐like morphology. A possible mechanism for the thread‐like assembly morphology was also discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Isothermal crystallization of HDPE/octamethyl polyhedral oligomeric silsesquioxane nanocomposites: Role of POSS as a nanofiller
Authors: Joshi M. , Butola B. S.
Published: April 2007

The isothermal crystallization of HDPE/POSS (polyhedral oligomeric silsesquioxane) nanocomposites (POSS content varying from 0.25 to 10 wt %) was studied using differential scanning calorimetry (DSC) technique. The Avrami model could successfully describe the isothermal crystallization behavior of the nanocomposites. The value of Avrami exponent (n) varies between 2 and 2.5 for all the compositions studied. For a given composition, the values vary with crystallization temperature and in general increased with POSS content up to 1 wt % POSS content and decreased thereafter. The presence of POSS was found to increase the rate of crystallization, which manifested itself in the increased value of the Avrami rate constant (K) and reduced value of crystallization half‐time (t1/2). The rate of crystallization peaked at 1 wt % POSS content and was almost constant at higher POSS loadings. X‐ray diffraction studies revealed that POSS exists as nanocrystals in HDPE matrix while some POSS gets dispersed at molecular level too. It is observed that only the POSS dispersed at molecular level acts as a nucleating agent while the POSS nanocrystals do not affect the crystallization process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Architecture of the primary taste center of Drosophila melanogaster larvae
Authors: Colomb Julien , Grillenzoni Nicola , Ramaekers Ariane , Stocker Reinhard F.
Published: April 2007

A simple nervous system combined with stereotypic behavioral responses to tastants, together with powerful genetic and molecular tools, have turned Drosophila larvae into a very promising model for studying gustatory coding. Using the Gal4/UAS system and confocal microscopy for visualizing gustatory afferents, we provide a description of the primary taste center in the larval central nervous system. Essentially, gustatory receptor neurons target different areas of the subesophageal ganglion (SOG), depending on their segmental and sensory organ origin. We define two major and two smaller subregions in the SOG. One of the major areas is a target of pharyngeal sensilla, the other one receives inputs from both internal and external sensilla. In addition to such spatial organization of the taste center, circumstantial evidence suggests a subtle functional organization: aversive and attractive stimuli might be processed in the anterior and posterior part of the SOG, respectively. Our results also suggest less coexpression of gustatory receptors than proposed in prior studies. Finally, projections of putative second‐order taste neurons seem to cover large areas of the SOG. These neurons may thus receive multiple gustatory inputs. This suggests broad sensitivity of secondary taste neurons, reminiscent of the situation in mammals. J. Comp. Neurol. 502:834–847, 2007. © 2007 Wiley‐Liss, Inc.
The eigenvalues and eigenfunctions of a spherically symmetric anharmonic oscillator
Authors: Isaacson David , Marchesin Dan
Published: April 2007

We show that the operator Hs has a complete set of eigenfunctions magnified image and eigenvalues magnified image, which satisfy magnified image [2l(l + 1) ‐ (3n2 + 3n + 1)]s + o(s) and lims→0 magnified image magnified image= 0. The functions magnified image are given in spherical coordinates as a product of generalized Laguerre functions and spherical harmonics.
Formation of singularities for wave equations including the nonlinear vibrating string
Authors: Klainerman Sergiu , Majda Andrew
Published: April 2007

Under very general assumptions, the authors prove that smooth solutions of quasilinear wave equations with small‐amplitude periodic initial data always develop singularities in the second derivatives in finite time. One consequence of these results is the fact that all solutions of the classical nonlinear vibrating string equation satisfying either Dirichlet or Neumann boundary conditions and with sufficiently small nontriviai initial data necessarily develop singularities. In particular, there are no nontrivial smooth small‐amplitude time‐periodic solutions.
Local boundary regularity of holomorphic mappings
Authors: Nirenberg L. , Webster S. , Yang P.
Published: April 2007

Let f be a holomorphic mapping between two bounded domains D and D' in complex space ℂn. Suppose that D and D' contain smooth real hypersurfaces Γ and Γ′ as open subsets of their respective boundaries, which correspond under a continuous extension of f. We shall show that this extension is smooth, given certain restrictions on Γ, Γ, and f.
Free vibrations for a nonlinear wave equation and a theorem of P. Rabinowitz
Authors: Brézis Haïm , Coron Jean‐Michel , Nirenberg Louis
Published: April 2007

A new and simpler proof is given of the result of P. Rabinowitz for nontrivial time periodic solutions of a vibrating string equation uu ‐ uxx + g(u) = 0 and Dirichlet boundary conditions on a finite interval. We assume essentially that g is nondecreasing, and g(u)/u→∞ as |u|→∞. The proof uses a modified form (PS)c of the Palais‐Smale condition (PS).
On the cauchy problem for harmonic maps defined on two‐dimensional Minkowski space
Authors: Chao‐Hao Gu
Published: April 2007

Let R1+1 be two‐dimensional Minkowski space and M a complete Riemannian manifold of dimension n. It is proved that the solution of the Cauchy problem for the harmonic map ϕ : R1+1 → M exists globally. As an application to physics we conclude that the field function in a two‐dimensional chiral field theory is regular for all time, if it is regular initially.
Expression profile of Papss2 (3′‐phosphoadenosine 5′‐phosphosulfate synthase 2) during cartilage formation and skeletal development in the mouse embryo
Authors: Stelzer Christiane , Brimmer Annette , Hermanns Pia , Zabel Bernhard , Dietz Uwe H.
Published: April 2007

Sulfation of proteoglycans is a very important posttranslational modification in chondrocyte growth and development. The enzyme 3′‐phosphoadenosine 5′‐phosphosulfate synthase (PAPSS) catalyzes the biosynthesis of PAPS (3′‐phosphoadenosine 5′‐phosphosulfate), which serves as the universal sulfate donor compound for all sulfotransferase reactions (Schwartz and Domowicz [2002] Glycobiology 109:143–151). Two major isoenzymes, PAPS synthase 1 (PAPSS1) and PAPS synthase 2 (PAPSS2) were identified in higher organisms for the synthesis of PAPS. PAPSS1 is the more prominent isoform and is ubiquitously expressed in human adult tissues, including cartilage, while PAPSS2 shows a more restricted expression pattern and appears to be the major variant in growth plate cartilage (Fuda et al. [2002] Biochem J 365(Pt 2):497–504). Mutations within the murine and the human PAPSS2 genes are responsible for diseases affecting the skeletal system (Kurima et al. [1998] Proc Natl Acad Sci USA 95:8681–8685; ul Haque et al. [1998] Nat Genet 20:157–162), like the spondyloepimetaphyseal dysplasia (SEMD) Pakistani type. To further elucidate the function of Papss2 within the developing skeleton, we investigated the expression pattern of the murine gene at different developmental stages. We detected Papss2 mRNA starting from 11.5 days post coitum (dpc) at the sites of first chondrogenic condensations and the expression continued in all cartilaginous elements tested of 12.5 dpc, 13.5 dpc, 16.5 dpc embryos, and newborn mice. Papss2 transcripts were also observed in other tissues such as heart, tongue, kidney, and neuronal tissues. However, the most significant levels of Papss2 mRNA were found in condensing and proliferating chondrocytes, whereas hypertrophic chondrocytes show a dramatic down‐regulation of Papss2 mRNA expression, indicating an important role of the gene product for cartilage growth and development in mouse embryo. Developmental Dynamics 236:1313–1318, 2007. © 2007 Wiley‐Liss, Inc.
Xenopus hairy2 functions in neural crest formation by maintaining cells in a mitotic and undifferentiated state
Authors: Nagatomo Kan‐Ichiro , Hashimoto Chikara
Published: April 2007

The neural crest is a population of mitotically active, multipotent progenitor cells that arise at the neural plate border. Neural crest progenitors must be maintained in a multipotent state until after neural tube closure. However, the molecular underpinnings of this process have yet to be fully elucidated. Here we show that the basic helix‐loop‐helix (bHLH) transcriptional repressor gene, Xenopus hairy2 (Xhairy2), is an essential early regulator of neural crest formation in Xenopus. During gastrulation, Xhairy2 is localized at the presumptive neural crest prior to the expression of such neural crest markers as Slug and FoxD3. Morpholino‐mediated knockdown of Xhairy2 results in the repression of neural crest marker gene expression while inducing the ectopic expression of the cell cycle inhibitor p27xic1 in the presumptive neural crest. We also found that ectopic p27xic1 disturbs neural crest formation. Furthermore, the depletion of Xhairy2 leads to the apoptosis of mitotic cells. Our results suggest that Xhairy2 functions in neural crest specification by maintaining cells in the mitotic and undifferentiated state. Developmental Dynamics 236:1475–1483, 2007. © 2007 Wiley‐Liss, Inc.
Nutritional endoderm in a direct developing frog: A potential parallel to the evolution of the amniote egg
Authors: Buchholz Daniel R. , Singamsetty Srikanth , Karadge Uma , Williamson Sean , Langer Carrie E. , Elinson Richard P.
Published: April 2007

The egg of the direct‐developing frog, Eleutherodactylus coqui, has 20× the volume as that of the model amphibian, Xenopus laevis. Increased egg size led to the origin of nutritional endoderm, a novel cell type that provides nutrition but does not differentiate into digestive tract tissues. As the E. coqui endoderm develops, a distinct boundary exists between differentiating intestinal cells and large yolky cells, which persists even when yolk platelets are depleted. The yolky cells do not become tissues of the digestive tract and are lost, as shown by histology and lineage tracing. EcSox17, an endodermal transcriptional factor, did not distinguish these two cell types, however. When cleavage of the yolky cells was inhibited, embryogenesis continued, indicating that some degree of incomplete cleavage can be tolerated. The presence of cellularized nutritional endoderm in E. coqui may parallel changes that occurred in the evolution of the amniote egg 360 million years ago. Developmental Dynamics 236:1259–1272, 2007. © 2007 Wiley‐Liss, Inc.
Drosophila Bcl‐2 proteins participate in stress‐induced apoptosis, but are not required for normal development
Authors: Sevrioukov Evgueni A. , Burr John , Huang Eric W. , Assi Hikmat H. , Monserrate Jessica P. , Purves Dianne C. , Wu Julie N. , Song Eyun J. , Brachmann Carrie Baker
Published: April 2007

Many developing tissues require programmed cell death (PCD) for proper formation. In mice and C. elegans, developmental PCD is regulated by the Bcl‐2 family of proteins. Two bcl‐2 genes are encoded in the Drosophila genome (debcl/dBorg1/Drob‐1/dBok and buffy/dBorg2) and previous RNAi‐based studies suggested a requirement for these in embryonic development. However, we report here that, despite the fact that many tissues in fruit flies are shaped by PCD, deletion of the bcl‐2 genes does not perturb normal development. We investigated whether the fly bcl‐2 genes regulate non‐apoptotic processes that require caspases, but found these to be bcl‐2 gene‐independent. However, irradiation of the mutants demonstrates that DNA damage‐induced apoptosis, mediated by Reaper, is blocked by buffy and that debcl is required to inhibit buffy. Our results demonstrate that developmental PCD regulation in the fly does not rely upon the Bcl‐2 proteins, but that they provide an added layer of protection in the apoptotic response to stress. genesis 45:184–193, 2007. Published 2007 Wiley‐Liss, Inc.
Enhanced transgenesis by intracytoplasmic injection of envelope‐free lentivirus
Authors: Yang Shang‐Hsun , Agca Yuksel , Cheng Pei‐Hsun , Yang Jin‐Jing , Agca Cansu , Chan Anthony Wing Sang
Published: April 2007

We demonstrate enhanced transgenesis in mice by intracytoplasmic injection of envelope‐free lentivirus. Envelope‐free lentivirus carrying the green fluorescent protein (GFP) gene under the control of the ubiquitin promoter (LVU‐GFP) was microinjected into the cytoplasm of mouse zygotes prior to embryo transfer. Ninety‐seven percent (31/32) of the adult mice were confirmed transgenic by PCR and Southern blot analysis; all founder mice express GFP when tail snips were examined by fluorescent microscopy prior to genomic DNA extraction. Transgene insertion numbers ranging from 1 to 32 were revealed by Southern blot analysis. Germline transmission was confirmed by the presence of transgene in F1 offspring. As expected, a lower transgenic rate (2.2%; 1/46) resulted when envelope‐free LVU‐GFP was microinjected into the perivitelline space (PVS) because cell recognition followed by membrane fusion between the viral envelope and the target cell is prerequisite for successful infection by envelope viruses. Here we demonstrate the competence of envelope‐free lentivirus in establishing stable gene integration by germline transgenesis in mice at high efficiency, by intracytoplasmic viral injection (INVI) of envelope‐free lentivirus into mouse zygotes. genesis 45:177–183, 2007. Published 2007 Wiley‐Liss, Inc.
Comparative analysis of Hoxa5 allelic series
Authors: Tabariès Sébastien , Lemieux Margot , Aubin Josée , Jeannotte Lucie
Published: April 2007

Analysis of the Hoxa5−/− mutants has revealed the critical role of Hoxa5 in survival, specification of axial identity, and ontogeny of organs, including the respiratory tract. The presence of the selection cassette in the original Hoxa5−/− mutation may interfere with the interpretation of the phenotypes. To circumvent this aspect and to bypass the lethality of the Hoxa5 mutation, we have designed a conditional approach and generated Hoxa5 allelic variants. The conditional allele (Hoxa5floxed) behaves as a wild‐type allele. In contrast, both the Hoxa5Δ and the Hoxa5floxneo alleles are characterized by the loss of the functional transcript and protein, the lethality due to lung defects and the skeletal homeotic transformations similar to those of the Hoxa5−/− mutants. Analysis of neighboring Hox gene expression patterns in the Hoxa5 mutants produced further confirmed that the Hoxa5 allelic variants are true null alleles. genesis 45:218–228, 2007. © 2007 Wiley‐Liss, Inc.
Effect of static magnetic field on cell migration
Authors: Hashimoto Yuichiro , Kawasumi Masashi , Saito Masao
Published: April 2007

The effect of a magnetic field on cells has long been investigated, but there are few quantitative investigations of the migration of cells. Cell migration is important as one of the fundamental activities of the cell. This study proposes a method to evaluate quantitatively the cell diffusion constant and the effect of a static magnetic field on cell migration. The cell lines are neuroblastoma (NG108‐15), fibroblastoma (NIH/3T3), and osteoblastoma (MC3T3‐E1). The static magnetic field of 30 or 120 mT is impressed by a permanent magnet in a vertical or horizontal direction to the dish. It is shown that the cell diffusion constant can represent the cell migration as the cell activity. It is found that the cell migration is enhanced by exposure to the magnetic field, depending on the kind of cell. It is conjectured that the static magnetic field affects cell migration, which is downstream of the information transmission. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(2): 46– 52, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20203
Improvement of the E&SS modeling considering phase correction for the field analysis considering two‐dimensional vector magnetic properties
Authors: Urata Shinya , Enokizono Masato , Todaka Takashi , Shimoji Hiroyasu
Published: April 2007

The two‐dimensional vector magnetic properties are proposed as a method to express the magnetic anisotropy and iron loss precisely by using the relationship between the flux density vector and the magnetic field strength vector. The E&S modeling [6] and the E&SS modeling [7–9] have enabled the representation of the two‐dimensional vector magnetic properties in FEM calculations. However, the calculated flux density waveform at each element has a phase difference depending on the excitation condition. In this paper, we have improved the E&SS modeling to solve the magnetic field problems under any exciting condition. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 1–9, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20446
Metabolic differences between Asian and Caucasian patients on clozapine treatment
Authors: Subramaniam Mythily , Ng Chee , Chong Siow‐Ann , Mahendran Rathi , Lambert Tim , Pek Elaine , Huak Chan Yiong
Published: April 2007

Objective

To establish if there are ethnic differences in the various metabolic disturbances that are common with clozapine treatment.

Method

Forty subjects (20 Asians and 20 Caucasians) with a diagnosis of schizophrenia were recruited for the study. Clozapine blood levels as well as fasting blood glucose, lipid levels, and liver function tests were established. Other clinical parameters such as blood pressure and Body Mass Index (BMI) were recorded for each patient.

Results

The mean clozapine dose was significantly higher in the Caucasian subjects (432.5 ± 194.7 mg) as compared to the Asian subjects (175.6 ± 106.9 mg) (p < 0.001) while the mean weight‐corrected dose for Asian patients was lower (3.0 ± 1.9 and 5.0 ± 2.1 mg/kg, respectively, p = 0.005). There were, however, no ethnic differences in the mean plasma clozapine concentration (415.3 ± 185.8 ng/ml in Caucasians and 417.1 ± 290.8 ng/ml in Asians). BMI were significantly higher in Caucasians, as were the number of subjects with hypertension; levels of hepatic enzymes were higher in the Asian group.

Conclusions

Not only are there pharmacokinetic differences between Asian and Caucasian patients receiving clozapine, but there may also be differential emergence of certain metabolic abnormalities like hypertension and weight gain in these two ethnic groups. However, the effects of life style including diet and exercise cannot be excluded. Copyright © 2007 John Wiley & Sons, Ltd.
Histone deacetylase inhibitor, suberoylanilide hydroxamic acid (Vorinostat, SAHA) profoundly inhibits the growth of human pancreatic cancer cells
Authors: Kumagai Takashi , Wakimoto Naoki , Yin Dong , Gery Sigal , Kawamata Norihiko , Takai Noriyuki , Komatsu Naoki , Chumakov Alexy , Imai Yasufumi , Koeffler H.Phillip
Published: April 2007

Tumor suppressor genes are often silenced in human cancer; this can occur by transcriptional repression by deacetylation in the promoter regions, mediated by histone deacetylase (HDAC). HDAC inhibitors can block cancer cell growth by restoring expression of tumor suppressor genes. In this study, we investigated the effects of a HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA) on pancreatic cancer cells. SAHA inhibited the growth of 6 pancreatic cancer cell lines in a dose‐dependent manner as measured by MTT and clonogenic assays (ED50 ≈10−6 M) associated with induction of apoptosis, G2 cell cycle arrest and also induced differentiation as indicated by morphology and increased expression of cytokeratin 7. It increased expression of p21WAF1 (independent of the mutational status of p53), C/EBPα, RARα and E‐cadherin; these genes have been associated with decreased proliferation in other cancers. SAHA decreased cyclin B1 expression; this cyclin normally promotes progression through G2 of the cell cycle. SAHA mediated acetylation of histone H3 globally, as well as, associated with the p21WAF1 promoter, as measured by chromatin immunoprecipitation. SAHA also decreased levels of c‐myc and cyclin D1, independent of an active β‐catenin pathway. In further studies, the combination of SAHA and an inhibitor of DNA methylation, 5‐Aza‐2′‐deoxycytidine, had an enhanced antiproliferative effect on pancreatic cancer cells. In summary, SAHA inhibited the growth of human pancreatic cancer cells by inducing apoptosis, differentiation and cell cycle arrest, as well as increase in the expression of several tumor suppressor genes. SAHA is a novel, promising therapeutic agent for human pancreatic cancers. © 2007 Wiley‐Liss, Inc.
Increased health care utilization among long‐term cancer survivors compared to the average Dutch population: A population‐based study
Authors: Mols Floortje , Helfenrath Kazimier A. , Vingerhoets Ad J.J.M. , Coebergh Jan Willem W. , van de Poll‐Franse Lonneke V.
Published: April 2007

In the present study, self‐reported health care utilization of cancer survivors is compared with those of an age‐ and gender‐matched normative population and predictors of health care utilization are identified. A population‐based, cross‐sectional survey among 1893 long‐term survivors of endometrial and prostate cancer and malignant lymphomas (Hodgkin's and non‐Hodgkin's) diagnosed between 1989 and 1998 was conducted using the cancer registry of the Comprehensive Cancer Centre South. Cancer survivors visited their general practitioner somewhat more often compared to the age and gender‐matched general Dutch population but this effect was not always statistically significant. In addition, they visited their medical specialist significantly more often. Survivors only sporadically (0–3%) visited or required a dietician, sexologist, oncology nurse, pastor, creative therapy or recovery program. Contact with a psychologist, physiotherapist and other cancer survivors took place somewhat more often. Patients visited a medical specialist less often if they were diagnosed with endometrial cancer (OR = 0.2; 95% CI = 0.1–0.5), if they were diagnosed between 10–15 years ago (OR = 0.6; 95% CI = 0.1–0.5) and if they were not married or divorced (OR = 0.5; 95% CI = 0.3–0.9). Contact with a psychologist was related to having a university or college degree (OR = 3.6; 95% CI = 1.3–9.4). Cancer survivors visited their specialist more often compared to the normative population. Changes in health care, such as less administrative work for the specialist and more efficiency, are probably necessary in order to cope adequately with the increasing demand on the system. © 2007 Wiley‐Liss, Inc.