bluuebunny/crossref_metadata_2025 huggingface dataset:
Longer growing seasons lead to less carbon sequestration by a subalpine forest
Authors: HU JIA , MOORE DAVID J. P. , BURNS SEAN P. , MONSON RUSSELL K.
Published: May 2009

As global temperatures increase, the potential for longer growing seasons to enhance the terrestrial carbon sink has been proposed as a mechanism to reduce the rate of further warming. At the Niwot Ridge AmeriFlux site, a subalpine forest in the Colorado Rocky Mountains, we used a 9‐year record (1999–2007) of continuous eddy flux observations to show that longer growing season length (GSL) actually resulted in less annual CO2 uptake. Years with a longer GSL were correlated with a shallower snow pack, as measured using snow water equivalent (SWE). Furthermore, years with a lower SWE correlated with an earlier start of spring. For three years, 2005, 2006, and 2007, we used observations of stable hydrogen isotopes (δD) of snow vs. rain, and extracted xylem water from the three dominant tree species, lodgepole pine, Engelmann spruce, and subalpine fir, to show that the trees relied heavily on snow melt water even late into the growing season. By mid‐August, 57% to 68% of xylem water reflected the isotopic signature of snow melt. By coupling the isotopic water measurements with an ecosystem model, SIPNET, we found that annual forest carbon uptake was highly dependent on snow water, which decreases in abundance during years with longer growing seasons. Once again, for the 3 years 2005, 2006, and 2007, annual gross primary productivity, which was derived as an optimized parameter from the SIPNET model was estimated to be 67% 77%, and 71% dependent on snow melt water, respectively. Past studies have shown that the mean winter snow pack in mountain ecosystems of the Western US has been declining for decades and is correlated with positive winter temperature anomalies. Since climate change models predict continuation of winter warming and reduced snow in mountains of the Western US, the strength of the forest carbon sink is likely to decline further.
Global warming and alternative causes of decline in arctic‐alpine and boreal‐montane lichens in North‐Western Central Europe
Authors: HAUCK MARKUS
Published: May 2009

Lichens are thought to be sensitive indicators of global warming, as the spread of several thermophilous epiphytes in north‐western Central Europe has been attributed to late 20th century warming. In the present paper, the potential contribution of late 20th century warming to the decline of arctic‐alpine and boreal‐montane lichen species is analyzed. Relevant ecological groups of lichens include terricolous heathland species, saxicolous species of exposed rock outcrops and boulder fields as well as epiphytes of mountain forests. These three groups of lichens experienced significant declines before the onset of late 20th century warming in the 1970s. These declines can be attributed to the abandonment of traditional land use systems in the case of the heathland lichens, increased recreational use of the exposed summits usually inhabited by cold‐tolerant saxicolous lichens, and to high atmospheric SO2 levels in the mid‐20th century, but are probably not directly connected to global warming.
Establishment of Italian ryegrass (Lolium multiflorum Lam.) by self‐seeding as affected by cutting date and degree of herbage removal in spring in pastures of the southern Great Plains of the United States
Authors: Bartholomew P. W. , Williams R. D.
Published: May 2009

Annually sown cool‐season small‐grain cereal species can provide a valuable source of cool‐season herbage for livestock in the southern Great Plains of the USA but limited access to field equipment for cultivation and sowing is an obstacle to their use. Italian ryegrass (Lolium multiflorum Lam.) (IRG) can persist through self‐seeding and may offer an alternative source of cool‐season herbage. The effects of cutting dates in mid‐April, early May or mid‐ to late May following sowing in the previous September, and of removing 0·57, 0·73 or 1·00 of the herbage mass at this time, on subsequent seed deposition, seedling re‐establishment and herbage production of IRG were measured. Later cutting dates reduced seed production, seed deposition, 1000‐seed weight and eventual re‐establishment of IRG seedlings. Removing different proportions of the herbage mass did not compensate for reduced seed deposition arising from later cutting dates. Numbers of seed heads and seed required to achieve a self‐seeded target population of 500 established seedlings m−2 ranged from 885 to 5650 seed heads m−2 and 3360 to 5850 deposited viable seeds m−2. Re‐establishment of IRG through self‐seeding showed a failure rate of 0·43 indicating that self‐seeded IRG will need periodic resowing. Any economic benefit derived from self‐seeded IRG will depend heavily on the success of its rate of re‐establishment.
Fatty acid composition and nutritive value of twelve cultivars of perennial ryegrass
Authors: Palladino R. A. , O’Donovan M. , Kennedy E. , Murphy J. J. , Boland T. M. , Kenny D. A.
Published: May 2009

A comparison was made of the fatty acid composition and nutritive value of twelve cultivars of perennial ryegrass (Lolium perenne L.) differing in heading date and ploidy level. The cultivars were sown in triplicate plots and three sequential cuts of herbage were taken at 20‐d intervals during the late spring and early summer to describe the fatty acid composition and other measurements of nutritive value. Differences between cultivars were recorded for DM content (P < 0·01) and concentrations of gross energy, neutral‐detergent fibre (NDF) and ash (P < 0·05). Diploid cultivars had a higher DM content and concentration of NDF (P < 0·01) than tetraploid cultivars whilst late‐heading date cultivars had the lower NDF (P < 0·05), ADF and ash (P < 0·01) concentrations. There was variation between cultivars in fatty acid composition. Diploid cultivars had a higher concentration of C18:0 (P < 0·01) and C18:1 (P < 0·05) than tetraploid cultivars and late‐heading date cultivars had the highest concentrations of total fatty acids, C16:0, C18:2 and C18:3 (P < 0·05). This was predominantly due to the cultivar Tyrella which is a diploid, late‐heading cultivar. The study showed that some variation exists between perennial ryegrass cultivars in concentrations of polyunsaturated fatty acids, which may present opportunities to select for this trait, but further research on the developmental stages and degree of leafiness of cultivars is first required.
Seed production of an Arrhenatherion elatioris hay‐meadow in the eastern Italian Alps
Authors: Scotton M. , Piccinin L. , Dainese M. , Sancin F.
Published: May 2009

Due to agricultural intensification, semi‐natural Arrhenatherion elatioris meadows are becoming rare in central Europe. Despite the increasing importance of their biodiversity value, little information is available on seed production which could be used to enlarge their regional presence. To contribute to this knowledge, the seed production of the major grass species were analysed for the spring growths of an Arrhenatherion elatioris meadow in 2003 and 2004. In the first study year, fertile culms of Anthoxanthum odoratum, Arrhenatherum elatius, Avenula pubescens, Dactylis glomerata, Holcus lanatus and Trisetum flavescens were collected on different dates and analysed for their reproductive efficiency. Floret site utilization was greater than 0·60 for all species and seed viability was above 80%, except for A. odoratum. Seed dormancy was present to a small extent only in A. odoratum and A. pubescens. With regard to the whole meadow, the density of fertile stems amounted to 850 m−2 (811 m−2 of which were grasses) and standing seed yield at seed maturity of the six grasses was about 33 100 seeds m−2. As a consequence of the increase in viability occurring during seed development, the maximum standing viable seed yield was reached later. The total number of seeds produced throughout the spring growth period was 2·8 times that of the maximum standing seed yield. The quality and quantity of the seed production from spring growth make it suitable for establishing species‐rich semi‐natural grassland provided that seed obtained from the second cut is included to increase the presence of legumes and forbs.
Predator size, prey size and threshold food densities of diving ducks: does a common prey base support fewer large animals?
Authors: Richman Samantha E. , Lovvorn James R.
Published: May 2009

1. Allometry predicts that a given habitat area or common prey biomass supports fewer numbers of larger than smaller predators; however, birds from related taxa or the same feeding guild often deviate from this pattern. In particular, foraging costs of birds may differ among locomotor modes, while intake rates vary with accessibility, handling times and energy content of different‐sized prey. Such mechanisms might affect threshold prey densities needed for energy balance, and thus relative numbers of different‐sized predators in habitats with varying prey patches.

2. We compared the foraging profitability (energy gain minus cost) of two diving ducks: smaller lesser scaup (Aythya affinis, 450–1090 g) and larger white‐winged scoters (Melanitta fusca, 950–1800 g). Calculations were based on past measurements of dive costs with respirometry, and of intake rates of a common bivalve prey ranging in size, energy content and burial depth in sediments.

3. For scaup feeding on small prey <12 mm long, all clams buried deeper than 5 cm were unprofitable at realistic prey densities. For clams buried in the top 5 cm, the profitability threshold decreased from 216 to 34 clams m−2 as energy content increased from 50 to 300 J clam−1.

4. For larger scoters feeding on larger prey 18–24 mm long, foraging was profitable for clams buried deeper than 5 cm, with a threshold density of 147 m−2 for clams containing 380 J clam−1. For clams <5 cm deep, the threshold density decreased from 86 to 36 clams m−2 as energy content increased from 380 to 850 J clam−1. If scoters decreased dive costs by swimming with wings as well as feet (not an option for scaup), threshold prey densities were 11–12% lower.

5. Our results show that threshold densities of total prey numbers for different‐sized ducks depend on prey size structure and depth in the sediments. Thus, heterogeneity in disturbance regimes and prey population dynamics can create a mosaic of patches favouring large or small predators. Whether a given area or total prey biomass will support greater numbers of larger or smaller predators will vary with these effects.
Review of recent genome‐wide association scans in lupus
Authors: Graham R. R. , Hom G. , Ortmann W. , Behrens T. W.
Published: May 2009

We review the systemic lupus erythematosus (SLE) human genetics literature, including the first wave of genome‐wide associations scans (GWAS), to identify confirmed and candidate risk variants that meet stringent statistical criteria. The understanding of the genetic basis of SLE in humans has expanded dramatically over the past year, offering an early glimpse into the primary genetic factors and major dysregulated pathways. A meta‐analysis of published candidate variants was performed incorporating data from a 1310 case and 7859 control GWAS. Our review of the literature and meta‐analysis identifies a total of 17 well‐validated common SLE risk variants, including four candidate variants that achieve our definition of a confirmed SLE risk locus. These variants account for a fraction of the total genetic contribution to SLE risk, with many risk loci remaining to be identified, but may provide insight into the pathways involved in SLE. Initial pathway analyses of the 17 confirmed SLE risk alleles indicate an important role for B‐cell signalling and development, signaling through toll‐like receptors 7 and 9, and neutrophil function.
Th17 cells in rheumatoid arthritis and systemic lupus erythematosus
Authors: Pernis A. B.
Published: May 2009

Recent work has implicated a novel Th effector cell subset, the Th17 cell subset, in the development of both rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) because of the ability of Th17 cells to produce cytokines like IL‐17 and IL‐21 that can drive both inflammatory and humoral responses. In this review, we will discuss recent studies that have begun elucidating the factors that regulate the development of Th17 cells and provide a brief overview of the role of Th17 cells in RA and SLE.
Receptor crosstalk: reprogramming B cell receptor signalling to an alternate pathway results in expression and secretion of the autoimmunity‐associated cytokine, osteopontin
Authors: Rothstein T. L. , Guo B.
Published: May 2009

Intracellular signalling emanating from the B‐cell antigen receptor is considered to follow a discrete course that requires participation by a set of mediators, grouped together as the signalosome, in order for downstream events to occur. Recent work indicates that this paradigm is true only for naïve B cells. Following engagement of the IL‐4 receptor, a new, alternate pathway for B‐cell receptor (BCR)‐triggered intracellular signalling is established that bypasses the need for signalosome elements and operates in parallel with the classical, signalosome‐dependent pathway. Reliance on Lyn and sensitivity to rottlerin by the former, but not the latter, distinguishes these two pathways. The advent of alternate pathway signalling leads to production and secretion by B cells of osteopontin (Opn). As Opn is a polyclonal B‐cell activator that is strongly associated with a number of autoimmune diseases including lupus and rheumatoid arthritis, this novel finding is likely to be clinically relevant. Our results highlight the potential role of B‐cell‐derived Opn in immunity and autoimmunity and suggest that stress‐related IL‐4 expression might act to strengthen immunoglobulin secretion at the risk of autoantibody formation. Further, these results illustrate receptor crosstalk in the form of reprogramming, whereby engagement of one receptor (IL‐4R) produces an effect that persists after the original ligand (IL‐4) is removed and results in alteration of the pathway, and outcome, of signalling via a second receptor (BCR) following its activation.
Lipid lowering versus pleiotropic effects of statins on skin microvascular function in patients with dysglycaemia and coronary artery disease
Authors: Settergren M. , Böhm F. , Rydén L. , Pernow J. , Kalani M.
Published: May 2009

Objectives.  To investigate the impact of lipid lowering therapy by different means on skin microvascular function in patients with dysglycaemia and coronary artery disease (CAD).

Design and setting.  Thirty‐six patients were randomized to simvastatin 80 mg daily (S80, n = 19) or ezetimibe 10 mg and simvastatin 10 mg daily (E10/S10, n = 17) for 6 weeks. Skin microvascular function was assessed by laser Doppler fluxmetry (LDF) at rest, following arterial occlusion (peak postocclusive LDF) and following local heating on the forearm (heat arm LDF) and foot (heat foot LDF). LDF parameters and serum lipids were evaluated at baseline and follow‐up.

Results.  At follow‐up, LDL cholesterol had decreased from 3.1 (2.7–3.5) to 1.6 (1.5–1.8) (mmol L−1) and 3.0 (2.4–3.9) to 1.3 (1.1–1.8) (mmol L−1) in the E10/S10 and S80 groups respectively. In the entire study group (n = 32), LDF parameters increased significantly; postocclusive LDF from 22 (17–27) to 26 (21–32) perfusion units (PU) (P < 0.001), heat foot LDF from 61 (44–82) to 66 (45–83) PU (P < 0.001) and heat arm LDF from 60 (48–121) to 75 (54–125) PU (P < 0.01). The changes in LDF parameters did not differ between the E10/S10 and S80 groups.

Conclusions.  Lipid lowering improves microvascular function in patients with dysglycaemia and CAD. The data suggest that lipid lowering per se is more important than pleiotropic effects of statins for this effect.
The Anti‐Dopaminergic Agent, Haloperidol, Antagonises the Feminising Effect of Neonatal Serotonin on Sexually Dimorphic Hypothalamic Nuclei and Tyrosine Hydroxylase Immunoreactive Neurones
Authors: Wilson C. A. , Dakin C. L. , Rico J. A. , Golmohamad A. , Ahmad‐Jauhari Y. , Davies D. C.
Published: May 2009

There is a transient fall in hypothalamic serotonin (5‐hydroxytryptamine; 5‐HT) activity in the second week post partum in male but not female rats. When this fall is masked by administration of the 5‐HT2 agonist (–) 2,5‐dimethoxy‐4‐iodophenyl]‐2‐aminopropane hydrochloride [(–)DOI], over days 8–16 post partum, males are feminised in adulthood. To investigate whether the effect of 5‐HT is mediated by dopamine and whether testosterone exerts its masculinising effect by reducing 5‐HT and dopamine activity, male pups were treated with (–)DOI alone or together with the dopamine antagonist, haloperidol, over days 8–16 post partum, whereas females were treated with testosterone propionate on day 2 post partum. In adulthood, the volumes of the anteroventral periventricular nucleus (AVPV), sexually dimorphic nucleus of the preoptic area (SDN‐POA) and arcuate nucleus (ARC) were determined, together with the number of tyrosine hydroxylase‐immunoreactive (TH‐ir) cells and fibres within them. The concentrations of 5‐HT, dopamine and their metabolites were also measured. (–)DOI treatment increased the volume of the AVPV, decreased that of the SDN‐POA and increased the number of TH‐ir cells in the AVPV. These feminising effects were antagonised by concurrent haloperidol treatment. Neonatal testosterone propionate masculinised the volumes of the female AVPV and SDN‐POA and reduced the number of TH‐ir cells in the AVPV. Dopamine and 5‐HT turnover in the AVPV was greater in female compared to male rats and neonatal testosterone propionate reduced dopamine concentration in the female AVPV. Neonatal (–)DOI had no effect on dopamine and 5‐HT activity in the AVPV but increased both in the ARC. The findings that TH‐ir neurone number and dopamine activity are greater in the female AVPV; the feminising effect of 5‐HT is prevented by a haloperidol; and the masculinising effect of testosterone propionate is accompanied by a decrease in TH‐ir neurone number and dopamine concentration in the female AVPV, suggest that dopamine is involved in hypothalamic sexual differentiation and may mediate the effect of 5‐HT.
Refocusing acute psychiatry, performance management, standards and accountability, a new context for mental health nursing
Authors: HARNETT P. J. , BOWLES N. , COUGHLAN A.
Published: May 2009

The term ‘performance management’ has an aversive ‘managerial’ aspect, is unappealing to many public sector staff and has an ‘image problem’. Perhaps as a consequence, it has failed to make a significant impact on Irish public sector workers, notably mental health nurses. In this paper, performance management is introduced and examined within an Irish healthcare context and with reference to its use in other countries. Some of the challenges faced by Irish mental health nurses and the potential benefits of working within a performance managed workplace are discussed. The paper concludes that performance management is likely to increasingly affect nurses, either as active agents or as passive recipients of a change that is thrust on them. The authors anticipate that the performance management ‘image problem’ will give way to recognition that this is a fundamental change which has the potential to enable health services to change. This change will bring high standards of transparency, worker involvement in decision making, an explicit value base for health services and individual teams. It provides the potential for clear practice standards and high standards of transparency as well as worker welfare in all aspects, including supporting employment and career progression.
Attitudes, knowledge and experience of nurses working in psychiatric hospitals in Greece, regarding borderline personality disorder: a comparative study
Authors: GIANNOULI H. , PEROGAMVROS L. , BERK A. , SVIGOS A. , VASLAMATZIS Gr.
Published: May 2009

The objectives of this study is to determine the knowledge, attitudes and experience of psychiatric nurses regarding clients with Borderline Personality Disorder (BPD) and to compare nurses working in Psychiatric Hospitals with those in Psychiatric Clinics of General Hospitals. The study was performed in two public Psychiatric Hospitals and the Psychiatric Clinics of two public General Hospitals in the area of Greater Athens. The 23‐item questionnaire of Clearyet al.was used in this study. It was sent to all nurses (n = 127) in 15 psychiatric wards. The staff have good enough knowledge regarding the diagnosis and treatment of the BPD patients. In Psychiatric Hospitals (A) the staff comes in contact with BPD patients less frequently than in the Psychiatric Clinics in General Hospitals (B). In the diagnostic question of ‘the unstable mood with rapid shifts’ most of the nurses who responded correctly belong to group A than to group B. In group A, nurses believe that not informing the patients of their disorder is the reason for their inadequate treatment, while in group B it is not reported as a reason. In group A, the staff consider that it is within their role to assess BPD patients, far more than in group B. Our hypothesis that nurses in psychiatric hospitals had less knowledge and experience as well as negative attitudes towards BPD patients was not confirmed, although the contact frequency with BPD patients was found statistically low.
The role of para‐aminophenol in acetaminophen‐induced methemoglobinemia in dogs and cats
Authors: McCONKEY S. E. , GRANT D. M. , CRIBB A. E.
Published: May 2009

Acetaminophen (APAP) overdose in most species is associated with hepatotoxicity because of the metaboliteN‐acetyl‐p‐benzoquinoneimine (NAPQI). In dogs and cats, APAP overdose primarily causes methemoglobinemia and hemolysis. Although NAPQI has been proposed as the responsible intermediate in dogs and cats, it lacks chemical or pharmacokinetic characteristics that favor methemoglobin formation. We hypothesized thatpara‐aminophenol (PAP) rather than NAPQI induces methemoglobinemia and that deficient arylamineN‐acetyltransferase (NAT) activity in dogs and cats contributes to this species‐dependent methemoglobinemia. Erythrocytes from dogs, cats, mice, and rats were exposedin vitroto APAP, NAPQI, and PAP. Only PAP induced methemoglobin and it induced more methemoglobin formation in dog and cat than rat and mouse erythrocytes. PAP also induced more methemoglobin in erythrocytes from Nat1/Nat2 knockout mice than wildtype (WT) mouse erythrocytes (P < 0.05), but less than in dog and cat erythrocytes (P < 0.01). APAP and PAP toxicity were comparedin vivoin WT and Nat1/Nat2 knockout mice. APAP caused no hematotoxicity while PAP induced more methemoglobin in NAT1/NAT2 knockout mice than in WT mice (P < 0.05). These results support the hypothesis that PAP is the metabolite responsible for APAP‐induced methemoglobinemia and that deficient NAT activity in dogs and cats contributes to this species‐dependent toxicity.
Variable patterns of introgression in two sculpin hybrid zones suggest that genomic isolation differs among populations
Authors: NOLTE A. W. , GOMPERT Z. , BUERKLE C. A.
Published: May 2009

Theory predicts that reproductive isolation may be due to intrinsic genetic incompatibilities or extrinsic ecological factors. Therefore, an understanding of the genetic basis of isolation may require analyses of evolutionary processesin situto include environmental factors. Here we study genetic isolation between populations of sculpins (Cottus) at 168 microsatellites. Genomic clines were fit using 480 individuals sampled across independent natural hybrid zones that have formed between one invading species and two separate populations of a resident species. Our analysis tests for deviations from neutral patterns of introgression at individual loci based on expectations given genome‐wide admixture. Roughly 51% of the loci analysed displayed significant deviations. An overall deficit of interspecific heterozygotes in 26% and 21% of the loci suggests that widespread underdominance drives genomic isolation. At the same time, selection promotes introgression of almost 30% of the markers, which implies that hybridization may increase the fitness of admixed individuals. Cases of overdominance or epistatic interactions were relatively rare. Despite the similarity of the two hybrid zones in their overall genomic composition, patterns observed at individual loci show little correlation between zones and many fit different genotypic models of fitness. At this point, it remains difficult to determine whether these results are due to differences in external selection pressures or cryptic genetic differentiation of distinct parental populations. In the future, data from mapped genetic markers and on variation of ecological factors will provide additional insights into the contribution of these factors to variation in the evolutionary consequences of hybridization.
Incipient ring speciation revealed by a migratory divide
Authors: IRWIN DARREN E.
Published: May 2009

Ever since Ernst Mayr (1942) called ring species the ‘perfect demonstration of speciation’, they have attracted much interest from researchers examining how two species evolve from one. In a ring species, two sympatric and reproductively isolated forms are connected by a long chain of intermediate populations that encircle a geographic barrier. Ring species have the potential to demonstrate that speciation can occur without complete geographic isolation, in contrast to the classic model of allopatric speciation. They also allow researchers to examine the causes of reproductive isolation in the contact zone and to use spatial variation to infer the steps by which speciation occurs. According to the classical definition, a ring species must have (i) gradual variation through a chain of populations connecting two divergent and sympatric forms, and (ii) complete or nearly complete reproductive isolation between the terminal forms. But evolutionary biologists now recognize that the process of speciation might often occur with some periods of geographic contact and hybridization between diverging forms; during these phases, even partial reproductive isolation can limit gene flow and permit further divergence to occur. In this issue Bensch et al. (2009) make an exciting and important contribution by extending the ring species concept to a case in which the divergence is much younger and not yet advanced to full reproductive isolation. Their study of geographic variation in willow warblers (Phylloscopus trochilus; Fig. 1) provides a beautiful example of gradual variation through a ring of populations connecting two forms that are partially reproductively isolated where they meet, possibly due to divergent migratory behaviours of the terminal forms.

 A male willow warbler resembling the southeastern‐migrating form (Phylloscopus trochilus acredula), on its breeding territory in central Sweden. (Photo: Anders Hedenström).

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Contribution of host plant resistance and geographic distance to the structure of Potato virus Y (PVY) populations in pepper in northern Tunisia
Authors: Ben Khalifa M. , Simon V. , Marrakchi M. , Fakhfakh H. , Moury B.
Published: May 2009

The genetic structure of Potato virus Y (PVY) populations was investigated in naturally‐infected pepper (Capsicum annuum) fields, collected at eight different localities in northern Tunisia, where 23% of the sampled plants were homozygous for the pvr21 recessive resistance allele, while the other plants carried the dominant susceptibility allele pvr2+. Restriction fragment length polymorphism analysis at three PVY genome segments revealed a high level of viral diversity, with a majority of cases showing co‐infection of individual plants by several PVY haplotypes and a strong genetic differentiation of viral populations collected in the different localities. Geographic distances affected the differentiation of PVY populations and isolation by distance among these populations was significant. However, the occurrence of the pvr21 resistance allele did not contribute to the structure of viral populations, suggesting that the virulence properties of the virus did not significantly affect its fitness. Consequently, greater deployment of the pvr21 gene would probably not be a suitable strategy to control PVY, and other resistance genes should be preferred.
Genetic dissection of Lactuca saligna nonhost resistance to downy mildew at various lettuce developmental stages
Authors: Zhang N. W. , Lindhout P. , Niks R. E. , Jeuken M. J. W.
Published: May 2009

This study used the pathosystem of lettuce (Lactuca spp.) and downy mildew (Bremia lactucae) as a model to investigate the inheritance of nonhost resistance, and focused on the contribution of quantitative trait loci (QTLs) to nonhost resistance at various developmental stages in the lettuce life cycle. A set of 28 backcross inbred lines (BILs) of L. saligna CGN05271 (nonhost) introgressions in a L. sativa cv. Olof (host) background identified 16 introgressions that contributed to resistance at various plant developmental stages: seedlings, young plants, adult plants in the greenhouse and adult plants in the field. This paper provisionally considered these introgressions to be 16 QTLs. Of these 16 QTLs, seven were identified previously and nine were new. For 15 QTLs (Rbq1, Rbq2, rbq3–7 and Rbq8–15), the resistance alleles were derived from the nonhost L. saligna; the resistance allele of the other QTL (Rbq16) was from the susceptible L. sativa cv. Olof. Of the 15 QTLs in L. saligna, only two, rbq5 and rbq7, were found to be effective at every plant developmental stage; the other 13 QTLs were only effective at certain developmental stages. Experiments with seven B. lactucae races did not provide evidence that any QTL was race‐specific. The data suggest that nonhost resistance in L. saligna is the result of cumulative effects of many resistance QTLs operating at various developmental stages.
Time‐shifted reproductive behaviours among fall armyworm (Noctuidae: Spodoptera frugiperda) host strains: evidence for differing modes of inheritance
Authors: SCHÖFL G. , HECKEL D. G. , GROOT A. T.
Published: May 2009

The noctuid moth Spodoptera frugiperda consists of two strains associated with different larval host plants (most notably corn and rice). These strains exhibit differential temporal patterns of female calling and copulation during scotophase, with the corn strain more active earlier in the night. We investigated strain‐specific constraints in reproductive timing, mating interactions between the two strains, and the mode of inheritance of timing of female calling, male calling, copulation and oviposition. We observed an allochronic shift of all reproductive behaviours by approximately 3 h and a parallel shift of nonreproductive locomotor activity, suggesting involvement of the circadian clock. The corn strain was more variable in the timing of calling and copulation than the rice strain. Rice strain females were more restricted in the timing of copulation than rice strain males, while such differences between the sexes were not apparent in the corn strain. There were significant interactions between the strains affecting onset times of copulation and male calling. The four investigated reproductive traits differed in their modes of inheritance: timing of female and male calling exhibited strong maternal effects, timing of copulation was controlled by a combination of maternal effects and corn strain dominant autosomal factors, and timing of oviposition was inherited in a corn strain dominant fashion. We conclude that the allochronic separation of reproduction between fall armyworm strains is asymmetric, less pronounced than previously thought, and under complex genetic control.
Experimental modifications imply a stimulatory function for male tsetse fly genitalia, supporting cryptic female choice theory
Authors: BRICEÑO R. D. , EBERHARD W. G.
Published: May 2009

One of the most sweeping of all patterns in morphological evolution is that animal genitalia tend to diverge more rapidly than do other structures. Abundant indirect evidence supports the cryptic female choice (CFC) explanation of this pattern, which supposes that male genitalia often function to court females during copulation; but direct experimental demonstrations of a stimulatory function have been lacking. In this study, we altered the form of two male genital structures that squeeze the female’s abdomen rhythmically in Glossina pallidipes flies. As predicted by theory, this induced CFC against the male: ovulation and sperm storage decreased, while female remating increased. Further experiments showed that these effects were due to changes in tactile stimuli received by the female from the male’s altered genitalia, and were not due to other possible changes in the males due to alteration of their genital form. Stimulation from male genital structures also induces females to permit copulation to occur. Together with previous studies of tsetse reproductive physiology, these data constitute the most complete experimental confirmation that sexual selection (probably by CFC) acts on the stimulatory properties of male genitalia.
Osteological Examinations on the Budgerigar (Melopsittacus undulatus Shaw 1805) with Special Reference to Skeletal Alterations Conditioned by Breeding
Authors: Bartels T. , Cramer K. , Wolf P. , Hässig M. , Boos A.
Published: May 2009

The aims of this study were to examine the skeleton of domesticated budgerigars of phenotypically different breeding types, to describe the expression of skeletal changes and to discuss the results with special reference to the causes and effects of breed‐conditioned alterations. Complete skeletons of 39 adult budgerigars of both sexes were the object of our research. The examinations demonstrated that almost all metrically sized skeleton dimensions of budgerigars of the exhibition type were increased significantly, compared with those of the non‐exhibition type. Only for the scapula significant length differences between the budgerigars of both breeding types could not be verified. It can be stated that the measuring parameters ‘occipital width’, ‘maxilla length’, ‘skull length’ and ‘prefrontal width’ are suitable for the characterization of exhibition budgerigars. However, sexual dimorphisms could be verified in only three parameters (width of the pars symphysialis mandibulae, height of the skull, width of the skull within the range of the occiput). It has to be clarified in future studies to what extent the changes in the skeleton of budgerigars of the exhibition type have already had consequences for their flying ability, metabolism, health and well‐being.
Ejaculatory dysfunction in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia
Authors: Rosen Raymond C. , Fitzpatrick John M.
Published: May 2009

OBJECTIVE

To assess, using the psychometrically validated Male Sexual Health Questionnaire (MSHQ), the prevalence of ejaculatory dysfunction (EjD) and bother due to EjD in men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH), and to assess predictors of EjD in this population.

PATIENTS AND METHODS

In all, 5999 sexually active men with LUTS completed the International Prostate Symptom Score (IPSS) which rates LUTS severity, and the MSHQ long‐form, which evaluates seven EjD symptoms and bother due to EjD. Concomitant intake of medical treatments for BPH and previous BPH‐related surgery were collected. The impact of treatments on EjD was compared to a control group (i.e. no previous BPH‐related surgery and no medical treatment for BPH). The relationship between EjD, bother due to EjD and selected clinical characteristics was analysed using multiple regression analysis.

RESULTS

EjD was highly prevalent and bothersome in men with LUTS, with decreased force of ejaculation (77.9%) and decreased amount of semen (74.4%) being the most commonly reported symptoms. LUTS severity was the strongest predictor of EjD and bother due to EjD. EjD was considered a problem by 35.6%, 51.6% and 64.1% of men with mild, moderate and severe LUTS, respectively (P < 0.001). EjD (except pain/discomfort on ejaculation) and bother due to EjD were also strongly related to age. Men with previous BPH‐related surgery and men treated with a 5α‐reductase inhibitor plus an α1‐blocker or tamsulosin alone showed the highest rates of dry ejaculation (67.4%, 57.2% and 52.3%, respectively) compared to controls (31.6%, P < 0.001). Conversely, in men treated with alfuzosin, most EjD symptoms were significantly lower than in controls. Bother due to EjD was also significantly lower with alfuzosin than in controls (34.4% vs 53.1%, P < 0.001) while there was no significant difference for other treatments.

CONCLUSIONS

EjD is highly prevalent and bothersome in sexually active men with LUTS, and is strongly related to LUTS severity and age. Treatment options for BPH do not have the same effect on EjD. EjD should be considered in the initial evaluation and clinical management of men with LUTS.
Erectile function after posterior urethroplasty for pelvic fracture‐urethral distraction defect injuries
Authors: Anger Jennifer T. , Sherman Neil D. , Dielubanza Elodi , Webster George D.
Published: May 2009

OBJECTIVE

To determine the specific effect of pelvic fracture‐urethral distraction defect (PFUDD) injuries on erectile function (EF) in men after pelvic fractures, and to compare EF to that found in other studies of men who sustained pelvic fractures, as currently the relationship between erectile dysfunction (ED) and PFUDD has not been elucidated using validated questionnaires.

PATIENTS AND METHODS

With approval from the institutional review board, patients who sustained a PFUDD injury and had a posterior urethroplasty from 1990 to 2004 were identified from a database. Patients were contacted by telephone, and those who were willing to participate were given the International Index of Erectile Function (IIEF) questionnaire. Using unpaired Student’s t‐tests, IIEF scores were compared to normal controls, and to results of other studies of men sustaining pelvic fractures.

RESULTS

In all, 26 men completed the IIEF, among whom EF was compromised in 14 (54%), including eight with severe ED (31%). Orgasmic function and ejaculation was maintained. Men with a PFUDD had significantly worse EF than men in other series with pelvic fractures.

CONCLUSIONS

Men who sustain a PFUDD are at significantly greater risk of ED than those with no urethral distraction injury. Men with PFUDD injuries represent a target population for early penile rehabilitation programmes.
Final outcomes of patients with low‐risk prostate cancer suitable for active surveillance but treated surgically
Authors: Louie‐Johnsun Mark , Neill Mischel , Treurnicht Karien , Jarmulowicz Michael , Eden Christopher
Published: May 2009

OBJECTIVE

To study the outcomes of a contemporary cohort of patients referred from around the UK with low‐risk prostate cancer consistent with the UK National Institute for Health and Clinical Excellence guidelines for active surveillance but who were treated with laparoscopic radical prostatectomy (LRP) in a single surgeon series.

PATIENTS AND METHODS

From 1080 consecutive patients who underwent LRP between March 2000 and April 2008, 549 patients (51%) had low preoperative risk disease (PSA level <10 ng/mL, clinical stage ≤T2a and biopsy Gleason score ≤6). The pathological outcomes of these 549 patients as well as a subgroup of 74 patients with preoperative prediction of ‘insignificant’ disease were assessed.

RESULTS

The mean age of the patients was 61 years, the mean (range) PSA level was 6.1 (1–9) ng/mL; 38% of patients were staged as cT2a. In all, 126 patients (23%) were upgraded on final pathology to Gleason score ≥7. In all, 29 patients (5%) had extraprostatic extension with seminal vesicle invasion in five (0.9%). Of the 74 patients with preoperative prediction of insignificant disease, 61% had significant disease with 16% upgraded to an intermediate‐risk group. Overall, there were positive margins in 44 patients (8.0%) and biochemical failure occurred in six patients (1.1%) with a median follow‐up of 28 months.

CONCLUSION

In this contemporary UK cohort of patients with apparently low‐ or favourable‐risk prostate cancer, 23% will have higher grade disease than preoperatively predicted. Even though active surveillance is increasingly being recommended for managing low‐risk localized prostate cancer, patients and their physicians need to be aware of the potential for harbouring more significant disease.
Mediational role of values in linking personality traits to political orientation
Authors: Caprara Gianvittorio , Vecchione Michele , Schwartz Shalom H.
Published: May 2009

Two studies use the Five Factor Model of traits andSchwartz's (1992) theory of basic personal values to assess the mediational role of values in linking traits to voting choice and left‐right ideology. Both left‐ and right‐wing voters showed distinctive traits and values that were congruent with their ideologies. Structural equation modelling supported a hypothesized full mediation model. Individuals' traits of openness, conscientiousness and agreeableness explained significant variance in the politically relevant values of security and universalism, and these self‐reported values, in turn, explained the voters' political orientations. These findings held across age (adolescents and adults) and were corroborated using both cross‐sectional and longitudinal data.
Neural Correlates of Children’s Theory of Mind Development
Authors: Liu David , Sabbagh Mark A. , Gehring William J. , Wellman Henry M.
Published: May 2009

Young children show significant changes in their mental‐state understanding as marked by their performance on false‐belief tasks. This study provides evidence for activity in the prefrontal cortex associated with the development of this ability. Event‐related brain potentials (ERPs) were recorded as adults (N = 24) and 4‐, 5‐, and 6‐year‐old children (N = 44) reasoned about reality and the beliefs of characters in animated vignettes. In adults, a late slow wave (LSW), with a left‐frontal scalp distribution, was associated with reasoning about beliefs. This LSW was also observed for children who could correctly reason about the characters’ beliefs but not in children who failed false‐belief questions. These findings have several implications, including support for the critical role of the prefrontal cortex for theory of mind development.
Pubertal Development: Correspondence Between Hormonal and Physical Development
Authors: Shirtcliff Elizabeth A. , Dahl Ronald E. , Pollak Seth D.
Published: May 2009

Puberty is advanced by sex hormones, yet it is not clear how it is best measured. The interrelation of multiple indices of puberty was examined, including the Pubertal Development Scale (PDS), a picture‐based interview about puberty (PBIP), and a physical exam. These physical pubertal measures were then associated with basal hormones responsible for advancing puberty. Participants included 160 early adolescents (82 boys). Puberty indices were highly correlated with each other. The physical exam stages correlated well with boys’ and girls’ testosterone and dehydroepiandrosterone and less so with girls’ estradiol. The PDS and PBIP were similarly related to basal hormones. Self‐report may be adequate when precise agreement is unnecessary. Multiple measures of puberty are viable options, each with respective strengths.
Social Dominance in Adolescence: The Moderating Role of the Classroom Context and Behavioral Heterogeneity
Authors: Jonkmann Kathrin , Trautwein Ulrich , Lüdtke Oliver
Published: May 2009

This study investigates socially dominant adolescents: students who are actively involved in establishing peer norms, influence their classmates’ opinions, and are often the center of attention. Data from 5,468 seventh graders (M age = 13.3; 53% girls) in 266 classrooms were used to examine how social dominance relates to achievement, peer acceptance and rejection, self‐perception, and deviance and to investigate contextual moderators of these associations. Multilevel analyses confirmed social dominance to be associated with both positive and negative adjustment. Moreover, the associations with achievement and disruptive behavior were moderated by the normativeness of these behaviors within the classroom. Finally, latent profile analyses revealed 4 distinct types of highly dominant students, 2 well adjusted and 2 poorly adjusted.
Direct and Extended Friendship Effects on Minority and Majority Children’s Interethnic Attitudes: A Longitudinal Study
Authors: Feddes Allard R. , Noack Peter , Rutland Adam
Published: May 2009

Longitudinal direct and extended cross‐ethnic friendship effects on out‐group evaluations among German (majority status,N = 76) and Turkish (minority status,N = 73) children (age 7–11 years) in ethnically heterogeneous elementary schools were examined at the beginning and end of the school year (time lag: 7 months). The results showed that among majority status children, but not minority status children, direct cross‐ethnic friendship predicted over time positive out‐group evaluations. This association was partly mediated by perceived social norms about cross‐ethnic friendship relations. No longitudinal effects of extended cross‐ethnic friendship were found. These results suggest that in ethnically heterogeneous contexts, direct friendship is more effective in changing intergroup attitudes than extended friendship and that social status moderates direct friendship effects.
Adolescent Civic and Political Engagement: Associations Between Domain‐Specific Judgments and Behavior
Authors: Metzger Aaron , Smetana Judith G.
Published: May 2009

Judgments and justifications for different forms of civic involvement and their associations with organized and civic behavior were examined in 312 middle‐class primarily White adolescents (M = 17.01 years). Adolescents applied moral, conventional, and personal criteria to distinguish involvement in community service, standard political, social movement, and social gathering activities. Males judged standard political involvement to be more obligatory and important than did females, who judged community service to be more obligatory and important than did males. For each form of civic involvement, greater involvement was associated with more positive judgments and fewer personal justifications. Structural equation modeling indicated that adolescents’ judgments about specific types of civic involvement were associated with similar forms of civic behaviors.
Maternal Reminiscing Style During Early Childhood Predicts the Age of Adolescents’ Earliest Memories
Authors: Jack Fiona , MacDonald Shelley , Reese Elaine , Hayne Harlene
Published: May 2009

Individual differences in parental reminiscing style are hypothesized to have long‐lasting effects on children’s autobiographical memory development, including the age of their earliest memories. This study represents the first prospective test of this hypothesis. Conversations about past events between 17 mother–child dyads were recorded on multiple occasions between the children’s 2nd and 4th birthdays. When these children were aged 12–13 years, they were interviewed about their early memories. Adolescents whose mothers used a greater ratio of elaborations to repetitions during the early childhood conversations had earlier memories than adolescents whose mothers used a smaller ratio of elaborations to repetitions. This finding is consistent with the hypothesis that past‐event conversations during early childhood have long‐lasting effects on autobiographical memory.