bluuebunny/crossref_metadata_2025 huggingface dataset:
Arabic validation of the short form of Urogenital Distress Inventory (UDI‐6) questionnaire
Authors: Altaweel Waleed , Seyam Raouf , Mokhtar Alaa , Kumar Pranesh , Hanash Kamal
Published: February 2009

Aims

To translate and validate the Arabic version of the short form of Urogenital Distress Inventory (UDI‐6) questionnaire in a sample of women with lower urinary tract symptoms (LUTS).

Methods

Two native Saudis independently translated the original UDI‐6 into Arabic. These two translations were harmonized, and then checked by independent back translation by two English teachers. They collaborated with the clinical investigators to reach a consensus version of the questionnaire. The harmonized version was pre‐tested in a pilot study on 20 patients. The final version of the UDI‐6 was applied to 68 consecutive patients aged 22 years or over complaining of LUTS for at least 3 months at our tertiary care hospital. The patients were rerated after 1 week to assess test–retest reliability. To assess the capacity of the questionnaire to discriminate between women with and without LUTS, cases, and controls of healthy women sample were involved and assessed. The psychometric properties of the questionnaire, such as reliability and validity were assessed.

Results

The correlation co‐efficient between ratings was >0.75 and the discriminate power between cases and control were confirmed. The UDI showed good internal consistency total score cronbach α = 0.71.

Conclusions

The Arabic version of UDI‐6 is a valid and robust instrument and a reliable method to use in daily practice and clinical research. Neurourol. Urodynam. 28:330–334, 2009. © 2009 Wiley‐Liss, Inc.
On the complexity of distributed graph coloring with local minimality constraints
Authors: Gavoille Cyril , Klasing Ralf , Kosowski Adrian , Kuszner Łukasz , Navarra Alfredo
Published: February 2009

Distributed greedy coloring is an interesting and intuitive variation of the standard coloring problem. Given an order among the colors, a coloring is said to be greedy if there does not exist a vertex for which its associated color can be replaced by a color of lower position in the fixed order without violating the property that neighboring vertices must receive different colors. We consider the problems of Greedy Coloring and Largest First Coloring (a variant of greedy coloring with strengthened constraints) in the Linial model of distributed computation, providing lower and upper bounds and a comparison to the (Δ + 1)‐Coloring and Maximal Independent Set problems, with Δ being the maximum vertex degree in G. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009
2007 Standards, Options, and Recommendations: Use of erythropoiesis‐stimulating agents (ESA: epoetin alfa, epoetin beta, and darbepoetin) for the management of anemia in children with cancer
Authors: Marec‐Berard Perrine , Chastagner Pascal , Kassab‐Chahmi Diana , Casadevall Nicole , Marchal Christian , Misset Jean‐Louis , Ray‐Coquard Isabelle
Published: February 2009

The Standards, Options, and Recommendations (SOR) project undertaken by the French National Federation of Cancer Centers (FNCLCC) to develop and disseminate clinical practice guidelines in oncology has now been taken over by the French National Cancer Institute. In 2007, the SOR updated the information related to the use of erythropoiesis‐stimulating agents (ESA) in anemic children with cancer. Updates were based on a review of the most reliable scientific data available, followed by critical appraisal by a multidisciplinary group of experts and validation by independent experts. The literature review identified four randomized trials likely to provide reliable new information on the use of ESA in children. This review confirmed four points: treatment increases hemoglobin levels and decreases the need for blood transfusions; no quality‐of‐life and no survival benefit has been demonstrated; treatment does not seem associated with significantly more side effects; impact on thromboembolic events and patient quality of life remains unclear. The main result of the study was the elaboration of a new standard of care unavailable at the time of the 2003 version. Systematic administration of ESA is not recommended for the prevention or treatment of anemia in pediatric cancer patients. However, treatment decision must be made on a case‐by‐case basis and, when treatment is considered, the intravenous route must be preferred. The full French document is available at www.sor‐cancer.fr. Pediatr Blood Cancer 2009;53:7–12. © 2009 Wiley‐Liss, Inc.
A case–control study of childhood acute lymphoblastic leukaemia and polymorphisms in the TGF‐β and receptor genes
Authors: Dai Liping , Gast Andreas , Horska Alexandra , Schrappe Martin , Bartram Claus R. , Hemminki Kari , Kumar Rajiv , Bermejo Justo Lorenzo
Published: February 2009

Background

Inherited genetic variants in critical genes can putatively modulate susceptibility to childhood acute lymphoblastic leukemia (ALL).

Methods

We used allelic discrimination method to genotype 19 polymorphisms in the transforming growth factor‐β1 (TGF‐β1), transforming growth factor‐β receptor 1 (TGF‐βR1) and transforming growth factor‐β receptor 2 (TGF‐βR2) genes in 460 cases of childhood acute ALL and 552 ethnically matched controls. The genotyped polymorphisms included functional and tagging variants to cover the three genes in entirety. We used multidimensionality reduction (MDR) method to test effect of multiple genes on disease susceptibility. In order to increase statistical power and detect susceptibility variants not directly genotyped in this study, we used imputation using HapMap data.

Results

None of the genotyped polymorphisms or the consequent haplotypes showed any association with risk modulation. The results, however, did show a marginal association (odds ratio OR 0.76, 95% confidence interval CI 0.59–0.97) of the variant allele for the rs10417924 polymorphism located at 3′untranslated region of the TGF‐β1 gene with the B‐cell lineage ALL. No other polymorphism showed any association with childhood ALL susceptibility. A signal of marginal significance for the rs10417924 polymorphism in the TGF‐β1 gene in B‐cell lineage ALL showed up with both MDR and imputation techniques.

Conclusion

These data rule out the role of polymorphisms in the TGF‐β1, TGF‐βR1 and TGF‐βR2 genes in susceptibility to childhood ALL. However, for B‐lineage ALL, the role of the rs10417924 polymorphism in TGF‐β1 gene needs further investigation. Pediatr Blood Cancer 2009;52:819–823. © 2009 Wiley‐Liss, Inc.
Outcome of recurrent or refractory acute lymphoblastic leukemia in infants with MLL gene rearrangements: A report from the Japan infant leukemia study group
Authors: Tomizawa Daisuke , Koh Katsuyoshi , Hirayama Masahiro , Miyamura Takako , Hatanaka Michiki , Saikawa Yutaka , Ishii Eiichi
Published: February 2009

Background

Despite the poor outcome of recurrent or refractory acute lymphoblastic leukemia (ALL) in infants with MLL gene rearrangement, few studies have focused on this specific group. We conducted a retrospective analysis of infants with recurrent or refractory ALL from two previous consecutive Japanese studies to clarify the characteristics and prognostic factors among these patients

Procedure

All recurrent or refractory ALL infants with MLL gene rearrangement (MLL‐R) who were registered in two consecutive Japanese nation‐wide multicentric trials (MLL96 and MLL98; between 1995 and 2001) were eligible for the study.

Results

Among 80 MLL‐R ALL infants, 34 cases of recurrence and 5 induction failures occurred. The median duration of first remission was 5 months (range, 0–28 months). All patients underwent various salvage chemotherapies; remission was achieved in 40.5% (15/37). A total of 23 patients received subsequent hematopoietic stem cell transplantations (HSCT): 9 in remission, 12 without remission, and 2 with unknown status. With median follow‐up period of 5.5 years, the 5‐year overall survival (OS) rate after the second‐line treatment was 25.6% ± 6.9%. Young age (<3 months) and central nervous system involvement at initial diagnosis were associated with poor outcome; however, failure to achieve remission after salvage therapy was the sole independent poor prognostic factor in multivariate analysis (P = 0.01).

Conclusions

The prognosis of infants with recurrent or refractory MLL‐R ALL is extremely poor despite alternative treatments including HSCT; therefore, it is necessary to develop novel treatment strategies. Pediatr Blood Cancer 2009;52:808–813. © 2009 Wiley‐Liss, Inc.
Mechanical and thermal properties of functionalized multiwalled carbon nanotubes/cyanate ester composite
Authors: Wang Jinhe , Liang Guozheng , Yan Hongxia , He Shaobo
Published: February 2009

Multiwalled carbon nanotubes/cyanate ester composite using epoxy group as a bridge was prepared. After a two‐step functionalization, the epoxy groups were introduced on the surface of multiwalled carbon nanotubes (MWNTs) successfully, which was confirmed by X‐ray diffraction and Fourier transform infrared spectra. The mechanical and thermal properties of the cured cyanate ester resin and MWNTs/cyanate ester composites were examined by mechanical tests, scanning electron microscopy, and dynamic mechanical thermal analysis. The results showed that 2 wt% functionalized MWNTs can enhance the flexural strength and impact strength significantly and increase the glass transition temperature (Tg) slightly. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Mechanical properties of carbon black‐filled polypropylene/polystyrene blends containing styrene‐butadiene‐styrene copolymer
Authors: Al‐Saleh Mohammed H. , Sundararaj Uttandaraman
Published: February 2009

Mechanical properties and morphology of carbon black (CB)‐filled polypropylene/polystyrene (PP/PS) blends with and without styrene‐butadiene‐styrene (SBS) tri‐block copolymer were studied as a function of PP/PS volume ratio and CB content. Blends were prepared by melt mixing in a batch mixer followed by compression molding. Incompatibility of the PP/PS blends was found to negatively influence the blends' tensile properties. Addition of 5 vol% SBS to the CB‐filled PP/PS blends was found to compatibilize the blends by reducing the interfacial tension and enhancing the interfacial adhesion. In general, SBS addition enhanced the yield stress of the co‐continuous CB‐filled PP/PS blends, reduced the Young's modulus and enhanced the elongation at yield for all blends studied. For the (70/30) PP/PS blends with and without SBS, yield stress of the blends filled with up to 3 vol% CB is close to that of the unfilled (70/30) PP/PS blends. Increasing CB loading to 5 vol% considerably increased the yield stress for the blends with and without SBS. A gradual increase in Young's modulus was reported with increasing CB content in the (70/30) PP/PS blends with and without SBS. Increasing CB loading up to 5 vol% did not influence the elongation at yield of the (70/30) PP/PS blend without SBS. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
High‐strength composites based on tung oil polyurethane and wood flour: Effect of the filler concentration on the mechanical properties
Authors: Casado U. , Marcovich N.E. , Aranguren M.I. , Mosiewicki M.A.
Published: February 2009

New composite materials with a high percentage of their composition based on renewable resources, matrix and reinforcement, were prepared. The excellent compatibility of the main phases lead to an unusual outstanding composite behavior as follows: higher modulus and strength, but also higher deformability and fracture resistance than the neat polymer. A bio‐based polyol was obtained by chemical modification of tung oil to be used in the production of polyurethane composites reinforced with pine wood flour (WF). The mechanical behavior as a function of wood flour content was evaluated through tensile and impact tests. Increasing the filler content induced an increase in tensile modulus and strength as well as in impact strength. Composites containing 10 and 15 wt% of wood flour presented higher tensile ultimate strain than that of the unfilled polyurethane. These results were explained by a strong interfacial adhesion (physical and chemical bonding), which was also supported by SEM micrography and strength modeling. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Interpeptide interactions induce helix to strand structural transition in Aβ peptides
Authors: Takeda Takako , Klimov Dmitri K.
Published: February 2009

Replica exchange molecular dynamics and all‐atom implicit solvent model are used to compute the structural propensities in Aβ monomers, dimers, and Aβ peptides bound to the edge of amyloid fibril. These systems represent, on an approximate level, different stages in Aβ aggregation. Aβ monomers are shown to form helical structure in the N‐terminal (residues 13 to 21). Interpeptide interactions in Aβ dimers and, especially, in the peptides bound to the fibril induce a dramatic shift in the secondary structure, from helical states toward β‐strand conformations. The sequence region 10–23 in Aβ peptide is found to form most of interpeptide interactions upon aggregation. Simulation results are tested by comparing the chemical shifts in Aβ monomers computed from simulations and obtained experimentally. Possible implications of our simulations for designing aggregation‐resistant variants of Aβ are discussed. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Annual intensification of the Somali jet in a quasi‐equilibrium framework: Observational composites
Authors: Boos William R. , Emanuel Kerry A.
Published: February 2009

The annual intensification of the Somali jet, which accompanies the onset of the Indian summer monsoon, is rapid compared to the evolution of the seasonal insolation forcing. Using observationally‐based data sets, the dynamic and thermodynamic changes accompanying the onset of this jet are presented. The abrupt component of jet onset is shown to occur over ocean about 1000km east of the East African highlands, and is accompanied by increases in both deep convection and baroclinic flow over the off‐equatorial Arabian Sea. These abrupt changes are well separated from the core of the cross‐equatorial jet, which is located over land adjacent to the East African highlands.

The onset of the Somali jet and the associated monsoon are then examined in a convective quasi‐equilibrium framework. Such a framework is consistent with the mean summer state, in that peak free‐tropospheric temperatures are nearly collocated with peak subcloud layer entropies over the northern Bay of Bengal and adjacent coastal regions. Jet onset is accompanied by a large ($\hbox{O}\{100\ \hbox{W m}^{-2}\}$) increase in surface enthalpy flux over the Arabian Sea that is nearly collocated with, and linearly related to, the concurrent increase in deep tropospheric ascent. At the same time, the highest subcloud entropies shift inland slightly from the Bay of Bengal, and the region of warmest free‐tropospheric temperatures expands poleward. The consistency of all of these changes with a wind—evaporation feedback and several other hypothesized mechanisms of abrupt monsoon onset is discussed. Copyright © 2009 Royal Meteorological Society
Molecular structure and vibrational assignment of α‐chloro acetylacetone: A density functional theory study
Authors: Jalbout A. F. , Ali Naseri M. , Fazli M. , Raissi H. , Rezaei M. , Nowroozi A. , de Leon A.
Published: February 2009

The intramolecular hydrogen bond, molecular structure, and vibrational frequencies of α‐chloro acetylacetone have been investigated. Fourier transform infrared and Fourier transform Raman spectra of this compound and its deuterated analogue were recorded in the regions 400–4,000 cm−1and 50–4,000 cm−1, respectively. Rigorous normal coordinate analysis has been performed at the B3LYP/6‐311++G** level of theory for purposes of comparison. The complete vibrational assignment for TFAA has been made on the basis of the calculated potential energy distribution. We also applied the atoms in molecules theory and natural bond orbital method for the analysis of the hydrogen bond in α‐Chloro acetylacetone and acetylacetone. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Relation between resistance characteristics due to aquatic weed growth and the hydraulic capacity of the river Aa
Authors: De Doncker L. , Troch P. , Verhoeven R. , Bal K. , Desmet N. , Meire P.
Published: February 2009

Vegetation growth drastically influences water levels and flow patterns in lowland rivers. As soon as plants start to grow in spring, the flow resistance increases to reach a maximum in early summer.

The universities of Ghent and Antwerp are conducting scientific research in the river Aa in Belgium in order to better understand the relation between aquatic weed growth and the hydraulic capacity of the river and to come to a more accurate determination of the different influencing parameters.

Velocity measurements are performed in multiple cross‐sections on a regular basis and studied. Discharge calculations are based on velocity measurements, which deliver important information about structural characteristics of the river, presence of vegetation, etc. Removing the vegetation allows for determining species and vegetation density as well as for studying the influence of plants on flow distribution and patterns. It is shown that the resistance coefficient, influenced by the amount of biomass, is an important parameter for the hydraulic characteristics of the river. The presence of macrophytes and their blockage characteristics are studied and a relation between discharge, biomass and resistance coefficient is set up.

This leads to more reliable results in the application of hydraulic models for river management and river restoration purposes. Copyright © 2009 John Wiley & Sons, Ltd.
Passage and reproductive activity of fishes in the Igarapava fish ladder, Grande River, Southeastern Brazil
Authors: Casali Rubens C.V. , Vono Volney , Godinho Hugo P. , Luz Ronald K. , Bazzoli Nilo
Published: February 2009

We sampled fishes within the vertical‐slot Igarapava fish ladder (IFL), Grande River, southeastern Brazil, and immediately downstream IFL in 12 field trips from February 2000 to December 2002. A total of 1145 fishes belonging to 13 families and 39 species were captured. The most abundant species captured within the IFL, in order of abundance were: Pimelodus maculatus, Metynnis maculatus, Astyanax altiparanae, Hypostomus spp., Leporinus octofasciatus, Salminus hilarii, Leporinus elongatus, Leporinus friderici, Schizodon nasutus and Prochilodus lineatus. Size distribution of the most abundant fishes captured downstream or within the IFL was similar indicating no constraints to adult fish to ascend the IFL. Except P. maculatus, the number of migratory species captured in the IFL and downstream the IFL were very low. Some of the so‐called sedentary species were collected in the IFL indicating that they possess an innate behaviour to migrate. Juveniles of P. lineatus and P. maculatus were captured ascending the IFL implying a dispersal behaviour. Gonadal analyses of the fishes captured in the reproductive season showed that the overall number of reproductive active fishes (which included fish in maturation, mature and spawned/spent) surpassed those non‐active. Thus, the IFL offers upstream passage for juveniles, some of the so‐called sedentary species, as well as fishes in reproductive migration. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of Aqueous Enzymatic Processes on Sunflower Oil Quality
Authors: Latif Sajid , Anwar Farooq
Published: February 2009

The use of enzymes in aqueous vegetable oilseed extraction for simultaneous recovery of high quality oil and protein is gaining recognition. In the present work, five enzyme preparations [Protex 7L by Genencor (Rochester, NY USA), Alcalase 2.4L, and Viscozyme L by Novozymes (Bagsvaerd, Denmark), Natuzyme by Bioproton Pty Ltd (Australia) and Kemzyme by Kemin Europa N·V. (Belgium)] were studied to evaluate their effects on the extraction of oil and protein from sunflower seeds. Preliminary experiments were conducted for the selection of enzymes, optimum enzyme concentration, incubation time and pH. Maximum oil yield (87.25% of the total oil in the seed) was obtained with Viscozyme L, whereas, Protex 7L offered the highest level of protein in the aqueous phase. The comparison of the quality attributes of enzyme‐assisted aqueous extracted (EAAE) oil with those of solvent‐extracted and control (oils extracted without enzyme treatment) oils revealed no significant (P > 0.05) variations for iodine value, density, refractive index, unsaponifiable matter, and fatty acid composition among the extraction methods. The control and EAAE oils also exhibited a better oxidation state. The tocopherol concentration for the oils, produced with the enzymes, was noted to be quite improved relative to the control and solvent‐extracted oils. A higher antioxidant activity in terms of total phenolic contents, 2,2′‐diphenyl‐1‐picrylhydrazyl scavenging capacity and inhibition of linoleic acid peroxidation was also observed for the EAAE oils as against control and the solvent‐extracted oils.
Molecular markers indicate that the wheat curl mite, Aceria tosichella Keifer, may represent a species complex in Australia
Authors: Carew M. , Schiffer M. , Umina P. , Weeks A. , Hoffmann A.
Published: February 2009

The wheat curl mite (WCM), Aceria tosichella Keifer, is an eriophyoid pest of cereals, and the vector responsible for transmitting wheat streak mosaic virus. Several authors have suggested cryptic species of this mite identified through morphological variation, but this has never been conclusively demonstrated. Here, we use the mitochondrial 16S rRNA gene and two nuclear markers (internal transcribed spacer 1 and adenine nucleotide translocase) to show that WCM from Australia consists of at least two separate lineages that may represent putative species. In our study, both WCM variants were widespread and the only eriophyoids found on wheat varieties. The WCM variants were also found on alternate host plants, including some plants not known to host WCM. These results have implications for the control of this pest within Australian cereal crops.
Flight periodicity and the vertical distribution of high-altitude moth migration over southern Britain
Authors: Wood C.R. , Reynolds D.R. , Wells P.M. , Barlow J.F. , Woiwod I.P. , Chapman J.W.
Published: February 2009

The continuous operation of insect-monitoring radars in the UK has permitted, for the first time, the characterization of various phenomena associated with high-altitude migration of large insects over this part of northern Europe. Previous studies have taken a case-study approach, concentrating on a small number of nights of particular interest. Here, combining data from two radars, and from an extensive suction- and light-trapping network, we have undertaken a more systematic, longer-term study of diel flight periodicity and vertical distribution of macro-insects in the atmosphere. Firstly, we identify general features of insect abundance and stratification, occurring during the 24-hour cycle, which emerge from four years' aggregated radar data for the summer months in southern Britain. These features include mass emigrations at dusk and, to a lesser extent, at dawn and daytime concentrations associated with thermal convection. We then focus our attention on the well-defined layers of large nocturnal migrants that form in the early evening, usually at heights of 200–500 m above ground. We present evidence from both radar and trap data that these nocturnal layers are composed mainly of noctuid moths, with species such as Noctua pronuba, Autographa gamma, Agrotis exclamationis, A. segetum, Xestia c-nigrum and Phlogophora meticulosa predominating.
Widespread infestation of the exotic mealybug species,Phenacoccus solenopsis(Tinsley) (Hemiptera: Pseudococcidae), on cotton in India
Authors: Nagrare V.S. , Kranthi S. , Biradar V.K. , Zade N.N. , Sangode V. , Kakde G. , Shukla R.M. , Shivare D. , Khadi B.M. , Kranthi K.R.
Published: February 2009

A survey was conducted in 47 locations in nine cotton-growing states of India to identify the composition of mealybug species occurring on cotton. Results of the taxonomic study showed that two mealybug species, the solenopsis mealybug,Phenacoccus solenopsis(Tinsley), and the pink hibiscus mealybug,Maconellicoccus hirsutus(Green), were found to infest cotton plants from all nine cotton growing states of the country. However,P. solenopsiswas found to be the predominant mealybug species, comprising 95% of the samples examined.P. solenopsis, which was hitherto not reported to occur in India, now appears to be widespread on cotton in almost all cotton-growing states of the country.P. solenopsisis an exotic species originated from the USA and was reported to damage cotton and crops of 14 families. This report discusses the implications of the introduction of this exotic polyphagous pest species and the necessary steps to mitigate its potential threat to agriculture in India.
The genetic consequences of different dispersal behaviours in Lycaenid butterfly species
Authors: Habel J.C. , Schmitt T.
Published: February 2009

Many studies in population ecology have shown that related species have different dispersal behaviours. Species with sedentary and migratory behaviour exist in butterflies. While the genetic responses to population isolation are well studied, the effects of different dispersal behaviours of species are widely unknown. Therefore, we analysed 19 allozyme loci of two lycaenid butterflies,Cupido minimusas a sedentary butterfly andAricia agestisas a mobile and expansive species. We collected 594 individuals (280 ofC. minimusand 314 ofA. agestis) in a western German study region with adjacent areas in Luxembourg and northeastern France. The genetic differentiation among populations ofA. agestis(FST=3.9%) was lower than inC. minimus(FST=5.6%). Both species built up an isolation-by-distance system, which is more pronounced inA. agestisthan inC. minimus. The genetic diversity inC. minumuspopulations (e.g.Ptot=73.5%) is higher for all analysed parameters than inA. agestis(e.g.Ptot=52.1%). Both species show specific genetic characteristics fitting with their different dispersal behaviours and respective ecological strategies. In the light of conservation genetics, we deduce that highly fragmented populations do not necessarily have a high extinction probability, but this risk depending much more on specific population genetic structures. In the studied species,C. minimuspreserves a complex genetic constitution by high population densities. The patchily distributedA. agestisrepresents less rare alleles, present only in some populations, and holds up genetic diversity by high mobility.
Tissue-dwelling philometrid nematodes of the fish Arapaima gigas in Brazil
Authors: Santos C. Portes , Moravec F.
Published: February 2009

The nematode Rumai rumai Travassos, 1960 (Philometridae) is redescribed from the tissues of the mouth, tongue, operculum and head of the arapaima, Arapaima gigas (Schinz) (Osteichthyes), from Mexiana Island, Amazon River Delta, Brazil. Additional data on the related Nilonema senticosum (Baylis, 1922) from the same host and locality are also presented. Rumai rumai is characterized by the presence of a sclerotized formation on the female cephalic end, dorsal and ventral cephalic projections, the shape and structure of the oesophagus and a conical caudal extremity. Males of both R. rumai and N. senticosum, specific parasites of the ancient arapaima fish in the Neotropics, remain unknown. The relationship between these tissue-dwelling nematodes and the aquaculture system of Mexiana Island is commented upon.
FIRST-ORDER ASYMPTOTIC THEORY FOR PARAMETRIC MISSPECIFICATION TESTS OF GARCH MODELS
Authors: Halunga Andreea G. , Orme Chris D.
Published: February 2009

This paper develops a framework for the construction and analysis of parametric misspecification tests for generalized autoregressive conditional heteroskedastic (GARCH) models, based on first-order asymptotic theory. The principal finding is that estimation effects from the correct specification of the conditional mean (regression) function can be asymptotically nonnegligible. This implies that certain procedures, such as the asymmetry tests of Engle and Ng (1993,Journal of Finance48, 1749–1777) and the nonlinearity test of Lundbergh and Teräsvirta (2002,Journal of Econometrics110, 417–435), are asymptotically invalid. A second contribution is the proposed use of alternative tests for asymmetry and/or nonlinearity that, it is conjectured, should enjoy improved power properties. A Monte Carlo study supports the principal theoretical findings and also suggests that the new tests have fairly good size and very good power properties when compared with the Engle and Ng (1993) and Lundbergh and Teräsvirta (2002) procedures.
A comparison of traditional elasticity and variance-standardized perturbation analyses: a case study with the tropical tree species Manilkara zapota (Sapotaceae)
Authors: Cruz-Rodríguez Juan Antonio , López-Mata Lauro , Valverde Teresa
Published: February 2009

Knowledge of the population dynamics of tropical trees has expanded considerably in the past 20 years. An important observation deriving from these investigations is the confirmation that population behaviour varies both in time and space. A tool recently developed to evaluate the potential for variation in vital rates, and therefore in population growth rate, is variance-standardized perturbation analysis (VSPA). In this paper we report the results of a 2-y demographic analysis of a population of the tropical tree Manilkara zapota in a subtropical rain forest in the Mexican state of Veracruz, in which variance-standardized perturbation analysis was applied and compared with the results of the traditional elasticity analyses. To build population projection matrices, we tagged and followed a sample of 91 juvenile and adult individuals, and 635 seedlings. We subdivided the sample in nine size classes (defined by tree height and dbh; as well as leaf size, in the case of seedlings) and estimated transition probabilities and fecundity for each class. The demography of M. zapota varied greatly from the first to the second year of study (in 1998–1999, λ = 0.987, while in 1999–2000, λ = 1.038) due to negligible seed production during the first year and a massive reproductive event during the second. The largest elasticity values for both years corresponded to persistence of large juveniles and adults. Although the fecundity entries showed very low elasticity values, the variance-standardized perturbation analysis revealed the importance of these matrix entries; transition to larger categories and retrogression to smaller ones of saplings and juveniles were also important demographic processes contributing to variation in λ according to the VSPA. Thus, although the results of elasticity analysis and VSPA were similar for the 1998–1999 matrix, they differed substantially for the 1999–2000 matrix. In the latter, the VSPA enhanced the importance of demographic processes that are intuitively relevant for the population studied. This points toward the necessity of further exploring the use of VSPA, since it offers several advantages over the traditional elasticity analysis: it concentrates on the impact on λ of vital rates that actually vary, and the interpretation of the results is more realistic and straightforward.
Spatial ecology of hatchling water pythons (Liasis fuscus) in tropical Australia
Authors: Pizzatto Lígia , Madsen Thomas , Brown Gregory P. , Shine Richard
Published: February 2009

Young snakes are rarely seen in the field and little is known about their habits, mostly because they are too small for radio-telemetry (the primary method for studying snake spatial ecology). However, the offspring of some larger species can be fitted with transmitters and we investigated the spatial ecology and habitat use of ten hatchling water pythons (Liasis fuscus: Pythonidae) in the floodplain of the Adelaide River, tropical Australia. Patterns of habitat use in the late wet season and during the dry season were similar to those of adults tracked in the same vicinity in an earlier study. Soon after release the young snakes moved to the floodplain, avoiding pasture areas. Diurnal refuge sites were typically in the base of grass clumps or below the soil surface, especially in sites with thick vegetation and deep, wide soil cracks. Adult snakes are more sedentary but move longer absolute distances (mean ± SE = 252 ± 50 m wk−1) than hatchlings (66.3 ± 41 m wk−1). However, hatchling snakes moved longer distances relative to body size (84.4 ± 1.1 body lengths wk−1) than did the previously studied adults (66.0 ± 1.1 body lengths wk−1). Mean and minimum body temperatures of the hatchlings were correlated with mean and minimum air temperatures, respectively.
A protocol for sampling vascular epiphyte richness and abundance
Authors: Wolf Jan H. D. , Gradstein S. Robbert , Nadkarni Nalini M.
Published: February 2009

The sampling of epiphytes is fraught with methodological difficulties. We present a protocol to sample and analyse vascular epiphyte richness and abundance in forests of different structure (SVERA). Epiphyte abundance is estimated as biomass by recording the number of plant components in a range of size cohorts. Epiphyte species biomass is estimated on 35 sample-trees, evenly distributed over six trunk diameter-size cohorts (10 trees with dbh > 30 cm). Tree height, dbh and number of forks (diameter > 5 cm) yield a dimensionless estimate of the size of the tree. Epiphyte dry weight and species richness between forests is compared with ANCOVA that controls for tree size. SChao1is used as an estimate of the total number of species at the sites. The relative dependence of the distribution of the epiphyte communities on environmental and spatial variables may be assessed using multivariate analysis and Mantel test. In a case study, we compared epiphyte vegetation of six Mexican oak forests and one Colombian oak forest at similar elevation. We found a strongly significant positive correlation between tree size and epiphyte richness or biomass at all sites. In forests with a higher diversity of host trees, more trees must be sampled. Epiphyte biomass at the Colombian site was lower than in any of the Mexican sites; without correction for tree size no significant differences in terms of epiphyte biomass could be detected. The occurrence of spatial dependence, at both the landscape level and at the tree level, shows that the inclusion of spatial descriptors in SVERA is justified.
Supplemental irrigation increases seedling performance and diversity in a tropical forest
Authors: Paine C. E. Timothy , Harms Kyle E. , Ramos Jesús
Published: February 2009

Diversity is positively correlated with water availability at global, continental and regional scales. With the objective of better understanding the mechanisms that drive these relationships, we investigated the degree to which variation in water availability affects the performance (recruitment, growth and survival) of juvenile trees. Precipitation was supplemented throughout two dry seasons in a seasonal moist forest in south-eastern Peru. Supplementing precipitation by 160 mm mo−1, we increased soil moisture by 17%. To generate seedling communities of known species composition, we sowed 3840 seeds of 12 species. We monitored the fates of the 554 seedlings recruited from the sown seeds, as well as 1856 older non-sown seedlings (10 cm ≤ height < 50 cm), and 2353 saplings (> 1 m tall). Watering significantly enhanced young seedling growth and survival, increasing stem density and diversity. Watering diminished the recruitment of species associated with upland forests, but increased the survival of both upland- and lowland-associated species. Though supplemental watering increased the growth of older seedlings, their density and diversity were unaffected. Sapling performance was insensitive to watering. We infer that variation in dry-season water availability may affect seedling community structure by differentially affecting recruitment and increasing overall survival. These results suggest that differential seedling recruitment and survival may contribute to the observed relationships between water availability, habitat associations and patterns of tree species richness.
Nocturnal activity by the primarily diurnal Central American agouti (Dasyprocta punctata) in relation to environmental conditions, resource abundance and predation risk
Authors: Lambert Thomas D. , Kays Roland W. , Jansen Patrick A. , Aliaga-Rossel Enzo , Wikelski Martin
Published: February 2009

An animal's fitness is in part based on its ability to manage the inherent risks (foraging costs, predation, exposure to disease) with the benefits (resource gain, access to mates, social interactions) of activity (Abrams 1991, Altizeret al. 2003, Lima & Bednekoff 1999, Rubenstein & Hohmann 1989, Wikelskiet al. 2001). Thus, understanding an animal's pattern of activity is key to understanding behavioural and ecological processes. However, while numerous laboratory methodologies are available to continuously quantify activity over long periods of time, logistical difficulties have greatly hindered activity studies of animals in the field (DeCoursey 1990).
Decreasing abundance of leaf-cutting ants across a chronosequence of advancing Atlantic forest regeneration
Authors: Silva Paulo S. D. , Bieber Ana G. D. , Leal Inara R. , Wirth Rainer , Tabarelli Marcelo
Published: February 2009

Leaf-cutting ants (species of Atta and Acromyrmex) are dominant herbivores and play a key role as ecosystem engineers of tropical and subtropical America (Fowler et al. 1989, Weber 1972). Not only are they among the most polyphagous and voracious herbivorous insects, cutting up to 15% y−1 of the leaf standing crop (Urbas et al. 2007, Wirth et al. 2003), but also they strongly affect the light environment and the nature of plant assemblages via ant-nest-mediated disturbances (Farji-Brener & Illes 2000, Hull-Sanders & Howard 2003, Moutinho et al. 2003). Some leaf-cutting ant species have turned into an omnipresent feature of present-day neotropical landscapes and a wealth of studies has documented their abundance to drastically increase with increasing agricultural land use, disturbance and deforestation/fragmentation (Fowler et al. 1986, Jaffe 1986, Terborgh et al. 2001, Vasconcelos & Cherrett 1995, Wirth et al. 2007). In view of their ecosystem engineering capacity and the ever-increasing conversion of tropical forests into agricultural landscapes (Wright 2005), it has been concluded that disturbance-driven accumulation of Atta colonies leads to far-reaching and deleterious consequences in present-day neotropical landscapes (Wirth et al. 2008). But what about the opposite scenario of regenerating forests? Is disturbance-mediated hyper-abundance of leaf-cutting ants a reversible phenomenon? We believe that this question is highly relevant because (1) knowledge of the dynamics of leaf-cutting ant populations during forest regeneration is lacking and (2) natural secondary succession has become a widespread phenomenon after land is abandoned or temporarily fallowed (Wright 2005). In the Brazilian Amazon during the 1990s, for example, secondary forests have reclaimed 31% of the once deforested land (Perz & Skole 2003).
Frugivores and fruit removal ofAntiaris toxicaria(Moraceae) at Bia Biosphere Reserve, Ghana
Authors: Kankam Bright Obeng , Oduro William
Published: February 2009

In tropical forests, most individual fruit-bearing trees depend on frugivores for seed dispersal (Howe & Smallwood 1982, Wilson 1992). Seed dispersal enhances germination potential, provides an opportunity for seeds to escape predation under the parent plants, and reduces seedling numbers under parent trees (Şekercioğluet al. 2004). The way frugivores handle seeds and process them may influence the seed fate of many plants (Janzen 1971). The quantity of seeds dispersed and the quality of dispersal provided by frugivores impact plant fitness (Herrera & Jordano 1981). Schupp (1993) defined the effectiveness of seed dispersal by frugivores as an empirical measure of quantity of seeds dispersed and quality of dispersal from the parent plant to a suitable microsite. Seed dispersal by frugivores increases the chances for seedling survival away from the vicinity of the parent plant because in tropical forests seed predation is concentrated under adult trees that prevent seedlings from establishing near parent trees (Howe & Miriti 2004).
Habitat and fig characteristics influence the bird assemblage and network properties of fig trees from Xishuangbanna, South-West China
Authors: Sanitjan Sawat , Chen Jin
Published: February 2009

To understand how fruit tree characteristics and microhabitats shape the assemblage of birds on fig trees and the pattern of fig–bird interactions, we observed and recorded, over 96 d and 816 h, the frugivorous birds visiting 32 individual trees belonging to 14 species ofFicusthat were distributed across four different sites. A total of 30 bird species were recorded as eating figs, comprising 66.7% of the total number of frugivorous bird species recorded at the four sites. Small passerine birds such as bulbuls were the dominant frugivores for fig species. The number of bird species visiting different fig trees was significantly influenced by the crop size and canopy volume. Fruit colour and fruit size did not significantly influence the number of bird species, whereas habitats appeared to influence the composition of visiting birds. The fig–frugivorous bird interaction was asymmetrically structured, and the degree of nestedness appeared to be influenced by the forest type and degree of disturbance: the degree of nestedness in non-limestone forest tended to be higher than limestone forest; forest with less disturbance tend to be more nested compared with the open forest with high disturbance.
Incidence of hepatitis C in drug injectors: the role of homelessness, opiate substitution treatment, equipment sharing, and community size
Authors: CRAINE N. , HICKMAN M. , PARRY J. V. , SMITH J. , WALKER A. M. , RUSSELL D. , NIX B. , MAY M. , McDONALD T. , LYONS M.
Published: February 2009

A prospective cohort study estimated the incidence of hepatitis C virus (HCV) in drug injectors in South Wales (UK). In total, 286/481 eligible seronegative individuals were followed up after approximately 12 months. Dried blood spot samples were collected and tested for anti-HCV antibody and behavioural data were collected at baseline and follow-up. HCV incidence was 5·9/100 person-years [95% confidence interval (CI) 3·4–9·5]. HCV incidence was predicted by community size [incident rate ratio (IRR) 6·6, 95% CI 2·11–20·51,P=0·001], homelessness (IRR 2·9, 95% CI 1·02–8·28,P=0·047) and sharing injecting equipment (IRR 12·7, 95% CI 1·62–99·6,P=0·015). HCV incidence was reduced in individuals in opiate substitution treatment (IRR 0·34, 95% CI 0·12–0·99,P=0·047). In order to reduce follow-up bias we used multiple imputation of missing data using switching regression; after imputation estimated HCV incidence was 8·5/100 person-years (95% CI 5·4–12·7). HCV incidence varies with community size, equipment sharing and homelessness are associated with increased HCV incidence and opiate substitution treatment may be protective against HCV.
An assessment of census techniques, habitat use and threats to Swamp FrancolinFrancolinus gularisin Koshi Tappu Wildlife Reserve, Nepal
Authors: DAHAL BHAGAWAN RAJ , McGOWAN PHILIP J. K. , BROWNE STEPHEN J.
Published: February 2009

Swamp FrancolinFrancolinus gularisis endemic to the Indian sub-continent, being found in India, Nepal and Bangladesh. It is threatened with extinction and is listed as ‘Vulnerable’, mainly as a result of habitat degradation and loss. This study investigated the distribution, habitat use, threats and most appropriate method for surveying the species at Koshi Tappu Wildlife Reserve in southeastern Nepal from February to July 2004. The most appropriate method, which recorded the highest number of birds (without double-counting), was identified as point counts undertaken early in the morning during the breeding season. The abundance estimate for the species was 15.5 ± 2.50 birds km−2. Habitat use, as compared with availability, differed significantly between seasons, with Woodland-Grassland and Wet Grassland preferred in the breeding season and summer. Dry Grassland and Woodland were preferred during the monsoon months. On average, 40.4 (± 15.6) people were recorded in the study area each day and there was a general trend for the number of birds to decrease with increasing numbers of people. Each day an average of 31.6 (± 16.7) livestock was recorded in the study area and more than 120 were regularly present throughout the eastern section, although there was no significant relationship between number of cattle and Swamp Francolin. We conclude that as long as the degree and distribution of anthropogenic pressures does not increase, the Swamp Francolin should survive at Koshi Tappu Wildlife Reserve. However, as the species is reliant on different habitats in different seasons, deterioration in the quality or extent of either of these could have a serious impact on the species.
Clinical profiles and outcomes for Omani children with dilated cardiomyopathy seen in a regional referral hospital
Authors: Jaiyesimi Olufemi , Kasem Mohamed
Published: February 2009

Objective

To provide an account of paediatric dilated cardiomyopathy as seen in a region of Oman, analysing the data from 32 consecutive children who received care in our unit between January, 1999, and August, 2007.

Results

The patients, of whom 17 were male, were aged between 5 weeks and 8 years at presentation, with a median of 7 months. The disease was deemed to be myocarditis-induced in one-third, and idiopathic in half. Cardiac failure, seen in almost four-fifths, was the most frequent presenting feature. Correspondingly, the cardiothoracic ratios were increased, to a mean of 68% in 20 infants, and to 65% in 8 older children, and the left ventricular ejection fraction depressed, to a mean of 41%, in the 23 patients in whom it could be evaluated. Patients in cardiac failure received various combinations of diuretics, inotropes, and captopril. In addition, 6 received carvedilol, and 3 intravenous immunoglobulin. Death occurred in 2 patients shortly after admission, one left the hospital against medical advice, and the remaining 29 were followed-up for a mean of 37 months, with a range from 2 to 102 months. Recovery was noted in one-third of the patients, with one-quarter showing improvement but still requiring anti-failure medications. Slightly over two-fifths died. Of those with the idiopathic form, 40% died, with death occurring in 46% of those deemed to have myocarditis-induced disease, in half of those presenting in infancy, and in 57% of those who presented in cardiac failure.

Conclusion

Dilated cardiomyopathy was often severe in our patients, albeit that the cause was frequently uncertain, and the response to standard anti-failure treatment unsatisfactory. Efforts should be intensified for unravelling its aetiology and improving medical treatment.
The Blalock-Taussig shunt: the social history of an eponym
Authors: Evans William N.
Published: February 2009

Creating eponyms for surgical procedures or medical discoveries can be a simple objective process of attaching names of innovators. Some eponyms, however, have a controversial history. Undertaking the first systemic-to-pulmonary arterial shunt required the combined efforts of Helen Taussig, Vivien Thomas, and Alfred Blalock. In this review, I attempt to look beyond the mechanics of attributing the eponym to the larger social history surrounding the term.