bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants of the parasite community of clariid fishes from Lake Victoria, Tanzania
Authors: Mwita Chacha , Nkwengulila Gamba
Published: November 2007

The factors that determine parasite assemblages among the clariid fishes of Lake Victoria, Tanzania were studied between August 2003 and February 2005. Six hundred and fifty-six fish belonging to seven species were necropsied and examined for parasites, from which 31 species of metazoan parasites were recorded. The community was dominated by the nematodes both in species and numbers. Most species were generalists with only two trematodes, Diplostomum mashonense and Tylodelphys species, being specialists of Clarias gariepinus. Ten species were considered core and predictable. Parasite species richness, number of individuals per host and Shannon–Wiener diversity indices were generally high. At the compound community level, a mean number of 7.8 parasites were shared among different species of fish and the maximum number of parasites species per fish at the infracommunity level was seven. Levels of similarity in parasite species richness at the component community level ranged from 29.6 to 61.5%. The study concludes that parasite communities in clariid fishes of Lake Victoria are structured by ecological factors. At the infracommunity level, host size, diet and vagility promoted a richer parasite community. At the compound level, two factors were crucial, namely the intermixing of the waters in the lake and the predominant and mobile C. gariepinus.
Responses of Heterodera glycines and Meloidogyne incognita to exogenously applied neuromodulators
Authors: Masler E.P.
Published: November 2007

Biogenic amines regulate important behaviours in nematodes and are associated with pharyngeal activity in plant-parasitic nematodes. A robust behavioural assay based upon nematode body movements was developed to expand the study of these and other neuroregulators in plant-parasitic nematodes. Dopamine, octopamine and serotonin each had significant but differing effects on the behaviour of soybean cyst nematode Heterodera glycines and root-knot nematode Meloidogyne incognita juveniles. Body movement frequency was increased twofold in H.glycines by 5 mM dopamine (P = 0.0001), but decreased by 50 mM dopamine in H. glycines (88%) and M. incognita (53%) (P <  0.0001). Movement frequency in both species was increased by 50–70% (P <  0.0001) by 50 mM octopamine, and 5 mM octopamine increased M. incognita movement frequency more than twofold (P <  0.0001). Movement frequency in each species was reduced by more than 90% by 5 mM serotonin (P <  0.0001). While amplitude of body movement in H. glycines was unaffected by any amine, it was significantly reduced in M.incognita by all amines (P <  0.0006). Stylet pulsing frequencies in either species were unaffected by dopamine or octopamine, but 5 mM serotonin stimulated pulsing in H. glycines by nearly 13-fold (P <  0.0001) and in M. incognita by more than 14-fold (P <  0.0001). The invertebrate neuropeptide FLRFamide (N-Phe-Leu-Arg-Phe) increased M. incognita body movement frequency 45% (P = 0.02) at 1 mM but did not affect stylet activity. Finally, H. glycines egg hatch was completely suppressed by 50 mM serotonin, and partially suppressed by 50 mM dopamine (75%; P <  0.0001) and 50 mM octopamine (55%; P <  0.0001).
Genitourinary schistosomiasis among pre-primary schoolchildren in a rural community within the Cross River Basin, Nigeria
Authors: Opara K.N. , Udoidung N.I. , Ukpong I.G.
Published: November 2007

In Africa, most schistosomiasis control programmes defined the age 5–19 years as the target population for nationwide control through the school systems, excluding the under fives. A study was therefore undertaken to determine the prevalence and intensity of genitourinary schistosomiasis in children aged 0–5 years (pre-primary) in Adim, a rural and endemic community within the Cross River Basin, Nigeria. Of the 126 children examined, 25 (19.8%) were infected with Schistosoma haematobium, with no significant difference (P > 0.05) in infection rates between boys (21.1%) and girls (18.2%). Both prevalence and intensity of infection increased significantly (P <  0.05) with age. The overall geometric mean egg count was 5.9 eggs/10 ml urine. There was no significant association (P > 0.05) between intensity in boys (6.2 eggs/10 ml urine) and girls (5.6 eggs/10 ml urine). A total of 32.5 and 27.8% of the children had haematuria and proteinuria, respectively; it was not gender specific (P > 0.05). Six species of snail were encountered, with Bulinus globosus being the most abundant and widespread. The results of this study have shown that pre-primary schoolchildren are a source of transmission of schistosomiasis in endemic communities and should be integrated into any control intervention.
Longevity ofEchinostoma caproniin Balb/c mice
Authors: Fried B. , Peoples R.C.
Published: November 2007

This study used Balb/c mice to examine the longevity ofEchinostoma caproni. Five mice each exposed to 75 encysted metacercariae (cysts) were necropsied at 23 weeks postinfection (PI) (160 days PI). Two of the 5 were infected with a total of 33 worms; 23 in one mouse and 10 in the other. Body and organ area measurements showed that these worms were robust and normal in appearance. No signs of atrophy of any of the genital structures were observed. The mean ± SE of eggs/uterus per worm (n = 10) was 243 ± 6. This strain of mouse will be suitable to study the effect of long-term survival on the host–parasite relationship ofE. caproniin Balb/c mice.
In vitroanthelmintic effects of cysteine proteinases from plants against intestinal helminths of rodents
Authors: Stepek Gillian , Lowe Ann E. , Buttle David J. , Duce Ian R. , Behnke Jerzy M.
Published: November 2007

Infections with gastrointestinal (GI) nematodes are amongst the most prevalent worldwide, especially in tropical climates. Control of these infections is primarily through treatment with anthelmintic drugs, but the rapid development of resistance to all the currently available classes of anthelmintic means that alternative treatments are urgently required. Cysteine proteinases from plants such as papaya, pineapple and fig are known to be substantially effective against three rodent GI nematodes,Heligmosomoides polygyrus,Trichuris murisandProtospirura muricola, bothin vitroandin vivo. Here, based onin vitromotility assays and scanning electron microscopy, we extend these earlier reports, demonstrating the potency of this anthelmintic effect of plant cysteine proteinases against two GI helminths from different taxonomic groups – the canine hookworm,Ancylostoma ceylanicum, and the rodent cestode,Rodentolepis microstoma. In the case of hookworms, a mechanism of action targeting the surface layers of the cuticle indistinguishable from that reported earlier appears to be involved, and in the case of cestodes, the surface of the tegumental layers was also the principal location of damage. Hence, plant cysteine proteinases have a broad spectrum of activity against intestinal helminths (both nematodes and cestodes), a quality that reinforces their suitability for development as a much-needed novel treatment against GI helminths of humans and livestock.
Squamous carcinoma arising in a branchial cleft cyst: have you ever treated one? Will you?
Authors: Devaney K O , Rinaldo A , Ferlito A , Silver C E , Fagan J J , Bradley P J , Suárez C
Published: November 2007

The existence of primary branchiogenic carcinoma – that is, carcinoma arising in a pre-existing branchial cleft cyst (a benign developmental cyst) – has in recent decades been the subject of increasing scepticism. Recognition of the propensity of a variety of head and neck sites – including in particular the tonsil – to give rise to cervical metastases while the primary tumours themselves remain undetected has given rise to the idea that virtually all cystic carcinomas of the neck represent metastatic deposits, whether or not their primary sites are found. A diagnosis of primary branchiogenic carcinoma should be viewed with extreme scepticism, and every effort should be made (e.g. imaging, panendoscopy, elective tonsillectomy) to exclude the existence of a primary site elsewhere, before considering a diagnosis of primary branchiogenic carcinoma.
Acute-phase and 1-year follow-up results of a randomized controlled trial of CBT versus Befriending for first-episode psychosis: the ACE project
Authors: Jackson H. J. , McGorry P. D. , Killackey E. , Bendall S. , Allott K. , Dudgeon P. , Gleeson J. , Johnson T. , Harrigan S.
Published: November 2007

Background

The ACE project involved 62 participants with a first episode of psychosis randomly assigned to either a cognitive behaviour therapy (CBT) intervention known as Active Cognitive Therapy for Early Psychosis (ACE) or a control condition known as Befriending. The study hypotheses were that: (1) treating participants with ACE in the acute phase would lead to faster reductions in positive and negative symptoms and more rapid improvement in functioning than Befriending; (2) these improvements in symptoms and functioning would be sustained at a 1-year follow-up; and (3) ACE would lead to fewer hospitalizations than Befriending as assessed at the 1-year follow-up.

Method

Two therapists treated the participants across both conditions. Participants could not receive any more than 20 sessions within 14 weeks. Participants were assessed by independent raters on four primary outcome measures of symptoms and functioning: at pretreatment, the middle of treatment, the end of treatment and at 1-year follow-up. An independent pair of raters assessed treatment integrity.

Results

Both groups improved significantly over time. ACE significantly outperformed Befriending by improving functioning at mid-treatment, but it did not improve positive or negative symptoms. Past the mid-treatment assessment, Befriending caught up with the ACE group and there were no significant differences in any outcome measure and in hospital admissions at follow-up.

Conclusions

There is some preliminary evidence that ACE promotes better early recovery in functioning and this finding needs to be replicated in other independent research centres with larger samples.
Cannabis abuse is associated with decision-making impairment among first-episode patients with schizophrenia-spectrum psychosis
Authors: Mata I. , Rodríguez-Sánchez J. M. , Pelayo-Terán J. M. , Pérez-Iglesias R. , González-Blanch C. , Ramírez-Bonilla M. , Martínez-García O. , Vázquez-Barquero J. L. , Crespo-Facorro B.
Published: November 2007

Background

Cannabis use appears to be a risk factor for schizophrenia. Moreover, cannabis abusers show impaired decision-making capacities, linked to the orbitofrontal cortex (OFC). Although there is substantial evidence that first-episode schizophrenia patients show impairments in cognitive tasks associated with the dorsolateral prefrontal cortex (DLPFC), it is not clear whether decision making is impaired at schizophrenia onset. In this study, we examined the association between antecedents of cannabis abuse and cognitive impairment in cognitive tasks associated with the DLPFC and the OFC in a sample of first-episode patients with schizophrenia-spectrum disorders.

Method

One hundred and thirty-two patients experiencing their first episode of a schizophrenia-spectrum psychosis were assessed with a cognitive battery including DLPFC-related tasks [backward digits, verbal fluency (FAS) and the Trail Making Test (TMT)] and an OFC-related task [the Iowa Gambling Task (GT)]. Performance on these tasks was compared between patients who had and had not abused cannabis before their psychosis onset.

Results

No differences were observed between the two groups on the performance of any of the DLPFC-related tasks. However, patients who had abused cannabis before their psychosis onset showed a poorer total performance on the gambling task and a lower improvement on the performance of the task compared to no-abusers.

Conclusions

Pre-psychotic cannabis abuse is associated with decision-making impairment, but not working memory and executive function impairment, among first-episode patients with a schizophrenia-spectrum psychosis. Further studies are needed to examine the direction of causality of this impairment; that is, does the impairment make the patients abuse cannabis, or does cannabis abuse cause the impairment?
Amygdala and ventral anterior cingulate activation predicts treatment response to cognitive behaviour therapy for post-traumatic stress disorder
Authors: Bryant R. A. , Felmingham K. , Kemp A. , Das P. , Hughes G. , Peduto A. , Williams L.
Published: November 2007

Background

Although cognitive behaviour therapy (CBT) is the treatment of choice for post-traumatic stress disorder (PTSD), approximately half of patients do not respond to CBT. No studies have investigated the capacity for neural responses during fear processing to predict treatment response in PTSD.

Method

Functional magnetic resonance imaging (fMRI) responses of the brain were examined in individuals with PTSD (n=14). fMRI was examined in response to fearful and neutral facial expressions presented rapidly in a backwards masking paradigm adapted for a 1.5 T scanner. Patients then received eight sessions of CBT that comprised education, imaginal andin vivoexposure, and cognitive therapy. Treatment response was assessed 6 months after therapy completion.

Results

Seven patients were treatment responders (defined as a reduction of 50% of pretreatment scores) and seven were non-responders. Poor improvement after treatment was associated with greater bilateral amygdala and ventral anterior cingulate activation in response to masked fearful faces.

Conclusions

Excessive fear responses in response to fear-eliciting stimuli may be a key factor in limiting responses to CBT for PTSD. This excessive amygdala response to fear may reflect difficulty in managing anxiety reactions elicited during CBT, and this factor may limit optimal response to therapy.
Four cases of acute flaccid paralysis associated with chikungunya virus infection
Authors: SINGH S. S. , MANIMUNDA S. P. , SUGUNAN A. P. , SAHINA  , VIJAYACHARI P.
Published: November 2007

The recent epidemic of chikungunya fever (2005–2006) in India has affected millions of people. The Andaman and Nicobar Islands, an archipelago situated in the Bay of Bengal 1200 km from peninsular India, also witnessed an outbreak of chikungunya fever starting in July 2006 which affected thousands of people. Chikungunya fever classically manifests as high fever, myalgia, arthralgia and arthritis and in a certain percentage of cases with maculopapular rashes. However, deviation from the classical clinical features of chikungunya fever was reported in the earlier and recent epidemics. During the recent epidemic in the Andaman and Nicobar Islands we came across ten cases of flaccid limb weakness following symptoms and signs suggestive of chikungunya fever. In four subjects we confirmed the diagnosis of chikungunya virus infection by serological method (IgM ELISA method). This is the case report of those four subjects.
Seasonality of clinical isolation of rapidly growing mycobacteria
Authors: HAN X. Y.
Published: November 2007

Rapidly growing mycobacteria (RGM) are environmental organisms that have emerged as significant human pathogens. RGM infections show remarkable geographic variations. In this study, based on data from Houston, Texas, RGM were isolated from clinical cultures year-round, although peaks in the summer and autumn correlating with the seasonal variation of temperature and rainfall also were noted. These results may offer some explanation for the summer occurrence of RGM outbreaks at diverse locations.
Multirate partial differential algebraic equations for simulating radio frequency signals
Authors: PULCH ROLAND , GÜNTHER MICHAEL , KNORR STEPHANIE
Published: November 2007

In radio frequency (RF) applications, electric circuits produce signals exhibiting fast oscillations, whereas the amplitude and frequency may change slowly in time. Thus, solving a system of differential algebraic equations (DAEs), which describes the circuit's transient behaviour, becomes inefficient, since the fast rate restricts the step sizes in time. A multivariate model is able to decouple the widely separated time scales of RF signals and provides an alternative approach. Consequently, a system of DAEs changes into a system of multirate partial differential algebraic equations (MPDAEs). The determination of multivariate solutions allows for the exact reconstruction of corresponding time-dependent signals. Hence, an efficient numerical simulation is obtained by exploiting the periodicities in fast time scales. We outline the theory of this multivariate approach with respect to the simulation of amplitude as well as frequency modulated signals. Furthermore, a survey of numerical methods for solving the arising problems of MPDAEs is given.
Beliefs of South Africans regarding food and cardiovascular health
Authors: Dolman Robin C , Stonehouse Welma , Riet Hilda van’t , Badham Jane , Jerling Johann C
Published: November 2007

Objectives

To investigate the beliefs of South African metropolitan adults regarding the importance of influencing cardiovascular health by eating certain food types, and to compare these beliefs between different race, living standards, age and gender groups.

Design

Randomised cross-sectional study. Trained fieldworkers administered questionnaires by conducting face-to-face interviews with consumers.

Subjects

Two thousand South Africans (16 years and older) were randomly selected from metropolitan areas in South Africa. The data were weighted to be representative of the total South African metropolitan population (N = 10 695 000) based on gender, age and race distribution.

Results

The majority (94 %) of the population indicated that it is important to influence cardiovascular risk-related health issues by eating certain food types, especially the higher LSM (Living Standard Measure) groups within the different race groups. Weight loss was considered the least important (61 % indicated that it is important) compared with cholesterol lowering (80 %), blood pressure (89 %), diabetes (86 %) and healthy blood vessels (89 %). In the higher LSM groups (7–10) higher proportions of respondents agreed than in the lower LSM groups (2 and 3). No differences were seen in responses between different gender, race and age groups.

Conclusions and recommendations

This study shows that the metropolitan South African adult population considers the influence on cardiovascular health by eating certain food types to be important. However, modifying weight loss by eating certain food types was considered less important.
Overweight and blood pressure: results from the examination of a selected group of adolescents in northern Italy
Authors: Turconi G , Maccarini L , Bazzano R , Roggi C
Published: November 2007

Objective

The aim of the present study was to investigate blood pressure (BP) levels and their relationship with different indices of body fat in a group of adolescents, in order to evaluate the prevalence of hypertension and plan preventive and corrective strategies.

Design

Cross-sectional study in primary care.

Setting

All high schools in the Aosta Valley region, northern Italy.

Subjects

Five hundred and thirty-two adolescents of both sexes, aged 15·4 (standard deviation 0·7) years. The following parameters were measured: body weight, body height, body mass index (BMI), four skinfold thicknesses, body fat mass, waist and hip circumferences and BP.

Results

BMI data indicated a high prevalence of overweight subjects in both sexes, but higher in males, while the prevalence rate of obese adolescents was lower. Of the total, 11·8 % of subjects suffered from systolic hypertension, while 6·9 % suffered from diastolic hypertension. In linear correlation analysis, BMI and all adiposity indices, except waist:hip ratio, were found to be significantly associated (P ranging between 0·05 and 0·001) with both systolic BP and diastolic BP in both sexes, with r ranging between 0·152 and 0·359. Multiple regression analysis with the stepwise method showed BMI and body fat mass to have the strongest association (P < 0·001) with BP, with r ranging between 0·275 and 0·359.

Conclusion

Unless reversed, these conditions are worrying and predict the possible development of cardiovascular disease in adulthood. There is a pressing need to develop a comprehensive medical and nutrition plan, together with preventive and corrective strategies, in school programmes.
Validation of the Radimer/Cornell food insecurity measure in rural Kilimanjaro, Tanzania
Authors: Leyna Germana H , Mmbaga Elia J , Mnyika Kagoma S , Klepp Knut-Inge
Published: November 2007

Objective

The objective of the present study was to assess the construct validity, criterion-related validity and internal consistency of the Radimer/Cornell food insecurity measure for use in rural Tanzania.

Design

A cross-sectional community-based survey was conducted from March to May 2005. Key adaptations to the nine-item Radimer/Cornell items included translation to Swahili, replacing the term ‘balanced diet’ with ‘full meal’ and constructing the items as questions rather than statements. Factor analysis and Cronbach’s alpha were used to assess validity and reliability, respectively.

Setting

Rural Kilimanjaro, Tanzania.

Subjects

Analysis was restricted to data from 530 women aged 15–44 years who had children under 5 years old.

Results

Principal component factor analysis revealed a two-factor solution: (1) altered eating pattern at household level and (2) altered eating pattern at child level. The two factors accounted for 66·2 % of the total variance. The subscales developed had good reliability. Internal consistency of the scales was 0·853 and 0·784 for food insecurity at household level and food insecurity at child level, respectively. Only 14·0 % of the women reported to be food-secure and 86·0 % reported some kind of food insecurity. The Radimer/Cornell food insecurity measure showed significant associations with selected sociodemographic factors in the expected directions. There was also an association with the NHANES III (Third National Health and Nutrition Examination Survey) and CCHIP (Community Childhood Hunger Identification Project) indicators.

Conclusion

Our findings suggest that the adapted Radimer/Cornell measure may have some utility in assessing food insecurity in settings like rural Tanzania.
Whole-grain intake as a marker of healthy body weight and adiposity
Authors: Harland Janice I , Garton Lynne E
Published: November 2007

Objective

To review evidence relating to the consumption of whole grains and healthy body weight (BW).

Design

Systematic review and analysis of observational studies reporting whole-grain consumption and measures of BW and adiposity, including the effect on macronutrient intakes and lifestyle factors.

Setting

Medline and other databases were searched for the period 1990 to 2006 to produce a full reference list; observational studies were retained for further analysis if they included an appropriate control group and reported whole-grain intake and body mass index (BMI) or a measure of adiposity.

Subjects

Fifteen trials were identified which included data from 119 829 male and female subjects aged 13 years and over.

Results

The combined and weighted mean difference in BMI from 15 studies representing 20 treatment groups (n= 119 829) using a random-effects model was 0·630 kg/m2lower when high versus low whole-grain intake was compared,P< 0·0001 (95 % confidence interval (CI) 0·460, 0·800 kg/m2). In high consumers, adiposity assessed as waist circumference was reduced by 2·7 (95 % CI 0·2, 5·2) cm,P= 0·03 (six data sets,n= 4178) or as waist:hip ratio by 0·023 (95 % CI 0·016, 0·030),P< 0.0001 (four data sets,n= 20 147). Higher intake of whole grains led to increased dietary fibre intake (9 g,P< 0·01), while total and saturated fat intakes decreased by 11 g and 3·9 g, respectively.

Conclusion

A higher intake of whole grains (about three servings per day) was associated with lower BMI and central adiposity. In addition, people who consume more whole grains are likely to have a healthier lifestyle as fewer of them smoke, they exercise more frequently and they tend to have lower fat and higher fibre intakes.
Associations of television viewing time with excess body weight among urban and rural high-school students in regional mainland China
Authors: Xu Fei , Li JieQuan , Ware Robert S , Owen Neville
Published: November 2007

Objective

To examine the relationship between television (TV) viewing and body mass index (BMI) among adolescents in a region of mainland China.

Design

Population-based cross-sectional study, conducted between September and November of 2004, on a sample of enrolled high-school students aged 12–18 years.

Setting

One hundred and sixty-eight classes randomly selected from both urban and rural areas and belonging to 15 senior and 41 junior high schools in Nanjing, China, with a regional population of 6·0 million.

Subjects

In total 6848 students participated; 47·7 % from urban and 52·3 % from rural areas; 49·0 % male and 51·0 % female. The response rate among eligible participants was 89·3 %.

Results

The proportion of overweight was 6·6 % according to the criteria of overweight recommended for Chinese adolescents. Boys than girls (8·9 % vs. 4·4 %) had higher odds of being overweight (odds ratio (OR) 2·12, 95 % confidence interval (CI) 1·74, 2·60), while the proportion of overweight was significantly lower among rural students than urban students (4·5 % vs. 8·9 %; OR 0·49, 95 % CI 0·40, 0·60). Those students who watched TV for more than 7 h/week had a 1·5 times greater odds of being overweight relative to their counterparts who watched TV for 7 h/week or less (adjusted OR 1·51, 95 % CI 1·24, 1·82). Furthermore, there was a positive linear relationship between TV viewing time and BMI, even after adjusting for age, gender, residence area, time spent in study, in sleeping and in physical activity, and monthly pocket money.

Conclusions

Viewing TV might increase the likelihood of being overweight for Chinese adolescents in China.
Fund management and its effect in the Greek social security system
Authors: MILONAS NIKOLAOS T. , PAPACHRISTOU GEORGE A. , ROUPAS THEODORE A.
Published: November 2007

Economic and demographic slowdown has put under strain public pension systems around the globe. In this paper, we discuss the characteristics of the Greek social security system and investigate the issue of pension fund management. Our empirical analysis focuses on whether flexible investment rules (including equity investment) could have taken the pressure off the Greek public pension system while reducing the risks associated with such flexibility. The empirical results of the paper suggest that efficient management of reserves can result in additional significant revenues at acceptable levels of financial risk. However, pension fund management flexibility cannot by itself resolve the problem of social security system.
An empirical analysis of the annuity rate in Chile
Authors: ROCHA ROBERTO , MORALES MARCO , THORBURN CRAIG
Published: November 2007

Empirical analyses of annuities markets have been limited to a few developed countries and restricted by data limitations. Chile provides excellent conditions for research on annuities due to the depth of its market and the availability of data. The paper utilizes a panel of life insurance company data to examine econometrically the main determinants of the annuity rate, defined as the internal rate of return on annuities. The results indicate that the annuity rate is determined by the risk-free interest rate, the share of privately issued higher yield securities in the portfolio of providers, as a proxy for the spread over the risk-free rate, the leverage of providers, the level of broker's commissions, the market share of individual providers, the level of the premium, and the degree of market competition. The results also show that efforts to improve market transparency produced structural shifts in the parameters of the annuity rate equation. The results are consistent with separate research on money's worth ratios, and indicate the need to develop appropriate financial instruments, allowing providers to hedge their risks while extracting higher returns, and also to ensure competition and transparency in annuities markets, in order to ensure good outcomes for annuitants.
Earnings management, expected returns on pension assets, and resource allocation decisions
Authors: ASTHANA SHARAD
Published: November 2007

This paper empirically examines the role of expected rate of return on pension assets reported under SFAS 87 as a tool for meeting and beating earnings targets and its effect on firm value. Results suggest that managers may use this pension assumption to inflate earnings per share (eps) when they are going to miss the earnings expectations. The earnings inflation is directly related to the amount by which earnings will miss the target and to earning sensitivity to expected return on pension asset assumption. The results are robust to two different measures of earnings inflation and two of earnings expectations.

The market behaves semi-efficiently and appears to adjust the firm value for large earnings inflations and in situations where firms have incentives to manipulate earnings or earnings are highly sensitive to expected rate of return on pension assets. However, this adjustment is not complete and post-announcement returns continue to depend on the inflated component of earnings, confirming that resource allocation decisions are based on managed earnings. Additional disclosure requirements to make pension assumptions more transparent are also discussed in the paper. Such disclosures could enhance the efficient use of the information by market participants.
On the financial sustainability of earnings-related pension schemes with ‘pay-as-you-go’ financing and the role of government-indexed bonds
Authors: ROBALINO DAVID A. , BODOR ANDRÁS
Published: November 2007

In this paper we reconsider the idea of an earnings-related pension system with reserves invested in indexed government bonds as a mechanism to both ensure financial sustainability and improve security. The paper starts by reviewing the characterization of the sustainable rate of return of an earnings-related pension system with pay-as-you-go financing. We show that current proxies for the sustainable rate, including the Swedish ‘gyroscope’, are not stable and propose an alternative measure that depends on the growth of the buffer-stock and the pay-as-you-go asset. Using a simple one-sector macroeconomic model that embeds a notional account pension system we then show how GDP-indexed government bonds, if combined with the right measure for the sustainable rate of return on contributions, could be used to generate a sustainable and secure earnings-related pension system, without becoming a fiscal burden. The proposal is particularly attractive for countries considering reforms to earnings-related systems that have accumulated a large implicit pension debt. In this case, the government bonds allow the financing of this debt in a transparent way. The proposed mechanism can also facilitate the transition to a fully funded pension system when the government bonds are allowed to be traded.
Effect of solute dissolution kinetics on cloud droplet formation: Extended Köhler theory
Authors: Asa‐Awuku A. , Nenes A.
Published: November 2007

This study focuses on the importance of solute dissolution kinetics for cloud droplet formation. To comprehensively account for the kinetics, a numerical model of the process was developed. Simulations of cloud droplet growth were performed for solute diffusivity, droplet growth rates, dry particle and droplet diameters relevant for ambient conditions. Simulations suggest that high ambient supersaturations and low solute diffusivity are major contributors to significant decreases in effective solute surface concentrations during droplet growth. The numerical simulations were incorporated into Köhler theory to assess the impact of dissolution kinetics on the droplet equilibrium vapor pressure. The modified Köhler theory implies that only CCN with slowly dissolving solute could have a “dynamical” equilibrium saturation ratio that is appreciably different from that obtained using thermodynamic equilibrium arguments alone.
Jovian S burst generation by Alfvén waves
Authors: Hess S. , Mottez F. , Zarka P.
Published: November 2007

Jupiter's radio emissions are dominated in intensity by decametric radio emissions due to the Io‐Jupiter interaction. Previous analyses suggest that these emissions are cyclotron‐maser emissions in the flux tubes connecting Io or Io's wake to Jupiter. Electrons responsible for the emission are thought to be accelerated from Io to Jupiter. We present simulations of this hot electron population under the assumption of acceleration by Alfvén waves in the Io flux tube. Outside of limited acceleration regions where a parallel electric field associated with Alfvén waves exists, the electrons are supposed to have an adiabatic motion along the magnetic field lines. Near Jupiter a loss cone appears in the magnetically mirrored electron population, which is able to amplify extraordinary (X) mode radio waves. The X‐mode growth rate is computed, which allows us to build theoretical dynamic spectra of the resulting Jovian radio emissions, whose characteristics match those observed for Jovian S bursts.
Influence of sea ice cover and icebergs on circulation and water mass formation in a numerical circulation model of the Ross Sea, Antarctica
Authors: Dinniman Michael S. , Klinck John M. , Smith Walker O.
Published: November 2007

Satellite imagery shows that there was substantial variability in the sea ice extent in the Ross Sea during 2001–2003. Much of this variability is thought to be due to several large icebergs that moved through the area during that period. The effects of these changes in sea ice on circulation and water mass distributions are investigated with a numerical general circulation model. It would be difficult to simulate the highly variable sea ice from 2001 to 2003 with a dynamic sea ice model since much of the variability was due to the floating icebergs. Here, sea ice concentration is specified from satellite observations. To examine the effects of changes in sea ice due to iceberg C‐19, simulations were performed using either climatological ice concentrations or the observed ice for that period. The heat balance around the Ross Sea Polynya (RSP) shows that the dominant term in the surface heat budget is the net exchange with the atmosphere, but advection of oceanic warm water is also important. The area average annual basal melt rate beneath the Ross Ice Shelf is reduced by 12% in the observed sea ice simulation. The observed sea ice simulation also creates more High‐Salinity Shelf Water. Another simulation was performed with observed sea ice and a fixed iceberg representing B‐15A. There is reduced advection of warm surface water during summer from the RSP into McMurdo Sound due to B‐15A, but a much stronger reduction is due to the late opening of the RSP in early 2003 because of C‐19.
Transport of anthropogenic aerosols from Asia and subsequent chemical transformation
Authors: Takami Akinori , Miyoshi Takao , Shimono Akio , Kaneyasu Naoki , Kato Shungo , Kajii Yoshizumi , Hatakeyama Shiro
Published: November 2007

Aerosol chemical composition and gaseous species were measured at Cape Hedo, Okinawa, Japan (CHO), during the ABC/EAREX project period in March 2005, using high‐time‐resolution instruments including an Aerodyne quadrupole aerosol mass spectrometer (Q‐AMS), a tapered element oscillating microbalance (TEOM), and gas monitors in order to investigate the transport and subsequent chemical transformation of aerosol in the east Asian region. Sulfate was the dominant species in fine aerosol mode and the average concentration of ammonium, sulfate and organics was 1.25, 6.37 and 2.16 μg m−3, respectively. The sulfate concentration observed at CHO in 2005 was about 1.5–2 times higher than that in 1994. For the majority of high‐sulfate observations, the air mass was transported from the central east Chinese region (between Shanghai and the Shandong Peninsula). Sulfate transport was intermittent and strongly correlated with the passage of synoptic‐scale high‐/low‐pressure systems. Chemical components and their concentration showed significant change on 17–18 March, which is accounted for by the change in air mass origin and the synoptic‐scale weather system. In addition, it is suggested that the difference of air quality at the air mass origin reflects the chemical composition at CHO. The high sulfate concentration required heterogeneous conversion of SO2 to sulfate at a rate of 2.0% h−1. A pronounced signal at m/z = 44 confirmed that organic compounds were oxidized.
Atmospheric carbonyl compounds in Chinese background area: A remote mountain of the Qinghai‐Tibetan Plateau
Authors: Mu Yujing , Pang Xiaobing , Quan Jiannong , Zhang Xiaoshan
Published: November 2007

The ambient concentrations of carbonyl compounds were measured in Waliguan (WLG) Observatory at the east edge of Qinghai‐Tibetan in August–September and December, 2005. The average concentrations of formaldehyde, acetaldehyde, acetone, and 2‐butenal were 4.16 ± 1.89, 4.25 ± 3.32, 2.02 ± 0.86, and 1.93 ± 1.58 ppbv (n = 42), respectively, in August–September and 1.48 ± 0.42, 3.91 ± 0.81, 1.88 ± 0.69, and 0.69 ± 0.16 ppbv (n = 12), respectively, in December. Biomass used as fuel for cooking by local residents was considered as the dominant source for 2‐butenal. Photooxidation of VOC (especially biogenic emission of isoprene) was one source for formaldehyde and methyl vinyl ketone in August–September. Animal excrement was probably an additional source for formaldehyde and acetone. Back trajectory analysis indicated that long‐distance transportation from polluted air might be one important source for formaldehyde, acetone, and acetaldehyde in WLG.
Turbulent flow and drag over fixed two‐ and three‐dimensional dunes
Authors: Venditti Jeremy G.
Published: November 2007

Detailed measurements of turbulent flow were obtained over a fixed flat bed, two‐dimensional (2‐D) dunes and four types of three‐dimensional (3‐D) dune morphologies including (1) full width saddles, (2) full width lobes, (3) sinuous crests, and (4) irregular shaped crests. The time‐averaged turbulence structure over the fixed flat bed was dynamically similar to flow over a flat bed with active sediment transport. The flow field over 2‐D dunes conforms with previous observations of flow over mobile and fixed bed forms. Bed form three dimensionality significantly altered the flow field observed over the 2‐D dunes. Lobe‐shaped dune crest lines, curved crests with topographic highs that bowed downstream, enhanced the level of turbulence producing a better defined wake structure and more vigorous mixing in the separation cell than observed over 2‐D dunes. Saddle‐shaped dune crest lines, curved crests with topographic highs that bowed upstream, diminished the level of turbulence suppressing a well‐defined wake structure and mixing in the flow separation cell. Flow over sinuous‐crested bed forms with lobes and saddles was dynamically similar to flow over full width bed forms. Development of in‐line paired saddles and lobes in the downstream direction appears to be controlled by near‐bed velocity gradients, which were larger over saddles and smaller over lobes. These gradients control local boundary shear stress patterns that should promote scour and high transport rates over saddles and deposition on lobes. Two‐dimensional and 3‐D bed forms with the same height and length offered different levels of flow resistance. The flow observations support the idea that saddles decrease flow resistance and lobes increase flow resistance relative to a 2‐D dune. Bed form crests composed of irregularly spaced lobes and saddles suppressed turbulent flow structure development and reduced drag by 20% below levels for 2‐D or sinuous crested dunes. The results suggest that bed form crest shape needs to be accounted for in flow resistance calculations and that a single drag coefficient is inadequate where the bed can evolve through 2‐D, 3‐D, and irregular 3‐D bed form states.
Identifying dissolved phosphorus source areas and predicting transport from an urban watershed using distributed hydrologic modeling
Authors: Easton Zachary M. , Gérard‐Marchant Pierre , Walter M. Todd , Petrovic A. Martin , Steenhuis Tammo S.
Published: November 2007

A reduction in surface water quality in urban watersheds due to nonpoint source phosphorus (P) loading has prompted municipalities to consider management practices to reduce P loss from landscapes. However, locating P source areas can be time consuming and expensive. Use of distributed models allows delineation of P source areas and focused management strategies. Using the spatially distributed soil moisture distribution and routing model, we adapt and validate a dissolved P (DP) loading model for application to an urban watershed, in Ithaca, New York, to identify P source areas. The model calculates DP loss separately for base flow, impervious surfaces, plant‐soil complex, and fertilized areas. The load at the outlet is the sum of P loss from the four components distributed throughout the watershed. Both stream and distributed DP loss were well predicted as indicated by comparison with measured data. The model predicted the largest contribution from plant‐soil complexes (36%). Impervious surfaces contributed 10% of the total load but as much as 17% in the winter. More important, the impervious surfaces increased DP losses from the adjacent areas due to runoff from the impervious surfaces saturating the soil, thus increasing runoff losses. Fertilizer contributed substantially following application but decreased rapidly thereafter, a result of conversion from soluble to insoluble P. However, fertilization increased soil P levels, and thus DP losses were higher as a whole (19%). Results demonstrate that correctly predicting the coincidence of P and runoff source areas can be a powerful tool to identify and mitigate contamination of surface waters.
Pore‐scale modeling of transverse dispersion in porous media
Authors: Bijeljic Branko , Blunt Martin J.
Published: November 2007

A physically based description is provided for the transverse dispersion coefficient in porous media as a function of Péclet number, Pe. We represent the porous medium as lattices of bonds with square cross section whose radius distribution is the same as computed for Berea sandstone and describe flow (Stokes equation) and diffusion (random walk method) at the pore scale (∼μm) to compute the transverse dispersion coefficient at a larger scale (∼cm to ∼m). We show that the transverse dispersion coefficient DT ∼ Pe for all Pe ≫ 1. A comprehensive comparative study of transverse dispersion with experiment indicates that the model can successfully predict the trends for the asymptotic macroscopic dispersion coefficient over a broad range of Péclet numbers, 0 < Pe < 105. We discuss the relation between transverse and longitudinal dispersion coefficient and show that unless one studies solute transport in the advection dominated regime, it is not appropriate to take DT to be 1 order of magnitude less than DL.
Annular modes and Hadley cell expansion under global warming
Authors: Previdi Michael , Liepert Beate G.
Published: November 2007

Projections of 21st century climate from the latest state‐of‐the‐art climate models consistently call for a poleward expansion of the tropical Hadley cell (HC) and subtropical dry zones (SDZ) in response to increasing levels of atmospheric greenhouse gases. We find that approximately half of the model‐simulated HC and SDZ expansion during the next hundred years can be explained by positive trends in the Northern Hemisphere and Southern Hemisphere annular modes (NAM and SAM), implying a close connection between changes in the tropical and extratropical atmospheric circulation. The link between NAM and SAM variability and the SDZ expansion suggests that future changes in the hydrologic cycle are likely to be strongly influenced by atmospheric dynamics.
Patagonia Icefield melting observed by Gravity Recovery and Climate Experiment (GRACE)
Authors: Chen J. L. , Wilson C. R. , Tapley B. D. , Blankenship D. D. , Ivins E. R.
Published: November 2007

Using recently released reprocessed gravity solutions from the Gravity Recovery and Climate Experiment (GRACE), we estimate the ice loss rate for the Patagonia Icefield (PIF) of South America, for the period April 2002 through December 2006. After postglacial rebound and hydrological effects are corrected, the estimated rate is −27.9 ± 11 km3/year, equivalent to an average loss of ∼−1.6 m/year ice thickness change if evenly distributed over the entire PIF area. The estimated contribution to global sea level rise is 0.078 ± 0.031 mm/year. This is an independent confirmation of relatively large melting rate estimates from earlier studies employing topographic and cartographic data.
Global morphology of substorm growth phases observed by the IMAGE‐SI12 imager
Authors: Coumans V. , Blockx C. , Gérard J.‐C. , Hubert B. , Connors M.
Published: November 2007

We present case studies and a statistical summary of optical observations of proton precipitation made during substorm growth phases. Our analysis is based on observations of the Doppler‐shifted Lyman‐α auroral emission obtained with the SI12 Spectrographic Imager on board the IMAGE satellite. These images are used to determine the morphology and dynamics of the auroral oval and of the polar cap boundary on a global scale, as well as the total open magnetic flux and its time evolution. We also investigate the relationship with the solar wind and the interplanetary magnetic field (IMF) characteristics measured by the ACE satellite and with the magnetic elevation angle measured by GOES‐8. The statistical study shows that the sector of maximum proton precipitation during the growth phase is on average centered around 2200 MLT and rapidly shifts in local time by about 1.2 h toward midnight at the time of the onset. The open magnetic flux increases by 33% on average during the growth phase. The mean value of the open flux immediately before the substorm onset is about 0.66 GWb for substorms triggered by a northward turning of Bz and 0.74 GWb for nontriggered substorms. The averaged open flux at the substorm onset is smallest when the substorm is triggered by a sudden reversal of Bz, suggesting that the accumulation of energy by the magnetosphere is perturbed by changes in Bz. The open magnetic flux continues to increase during the 20 min following the onset, for a large number of events. The rate of equatorward displacement of the auroral oval boundaries during growth phase is typically ∼3 deg/h. It is statistically correlated (r = 0.40) with the magnitude of the Bz component of the IMF measured by the ACE satellite. It is also correlated, with higher coefficient (r = 0.54), with functions describing the efficiency of solar wind energy transfer involving the transverse electric field carried by the solar wind. The equatorward motion may be global, restricted to local time sectors or a combination of both. At no nightside local time sector does the motion of the equatorial boundary appear more pronounced than at others, but the maximum displacement of the polar boundary is statistically located around midnight MLT.