bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation model of a predator‐prey system comprised ofPhytoseiulus persimilisandTetranychus urticae. II. Model sensitivity to variations in the life history parameters of both species and to variations in the functional response and components of the numerical response
Authors: Shaw Peter B.
Published: October 2006

A detailed sensitivity analysis of a model of a predator‐prey system comprised ofTetranychus urticaeandPhytoseiulus persimiliswas performed. The aim was to assess the relative importance of the life history parameters of both species, the functional response, and the components of the numerical response. In addition, the impact of the initial predator‐prey ratio and the timing of predator introduction were tested. Results indicated that the most important factors in the system were relative rates of predator and prey development, the time of onset of predator oviposition, and the mode of the predator's oviposition curve. The total oviposition of the predator, the effect of prey consumption on predator oviposition, and predator searching were important under some conditions. Factors of moderate importance were the adult female predator's functional response, total prey oviposition, the mode of the prey's oviposition curve, abiotic mortality of the pre‐adult predator, and the effect of prey consumption on predator development and on the immature predator's mortality. Factors of least importance were the variances of the predator's and prey's oviposition curves, the abiotic mortality of the adult predator, the abiotic mortality of the pre‐adult and adult prey, the functional response of the nymphal and adult male predators, and the effect of prey consumption on adult predator mortality. The sex ratios had little effect, except when the proportion of female predators was very low. The initial predator‐prey ratio and time of predator introduction had significant impacts on system behavior, though the patterns of impact were different.
Why small hermit crabs have large shells
Authors: Spight Tom M.
Published: October 2006

Frequent shell exchanges among hermit crabs imply the enigmatic circumstance that large crabs frequently obtain large shells from smaller crabs. This seeming anomaly is explored as a key to the shell resource system. It is hypothesized to reflect how, where, and how often shells become available to the crabs. Shells become available infrequently, as snails die, and are available to the crabs for only a brief time before they become inaccessible. The standing crop of empty shells is almost always low and is irrelevant to rates of shell turnover in the crab population. Crabs are most likely to encounter shells of the wrong size, and the chance of encountering a shell of the desired size decreases as a crab grows. Snails and crabs are usually found on different portions of the shore; thus, crabs must make “foraging trips” for shells. Under this regime of shell supply, a crab will get a suitable shell the fastest when it accepts any fresh shell that is larger than its initial shell. It can then trade with other crabs to improve its shell fit. This behavior will make small crabs into a regular source of large shells for large crabs, and a shell exchange ritual will be strongly favored because both participants will benefit. Shells are an unusual resource because they are the object of both competitive and mutualistic interactions. This ambiguous quality is revealed in the intraspecific and interspecific responses of crabs to each other and to shells.
Effects of host and parasitoid age on search behaviour and oviposition rates in Lariophagus distinguendusFörster (Hymenoptera: Pteromalidae)
Authors: Bellows T. S.
Published: October 2006

Oviposition rates and related behaviours were quantified for Lariophagus distinguendusFörster attacking Calosobruchus chinensis (L.) and C. maculatus (F.). Oviposition rates varied with parasitoid age; parasitoids aged 1–7 days laid approximately twice as many eggs per day as those aged 8–14 days. Similar differences were noted in search rates and handling times; younger parasitoids had higher attack rates and lower handling times than older parasitoids. Search rates and handling times also varied with the host stage available for attack. Search rates were higher and handling times were lower on larger stages. The results are discussed with reference to their impact on the dynamical behavior of insect parasitoid‐host populations.
A test ofJackson's method for separating death and emigration with mark‐recapture data
Authors: Manly B. F. J.
Published: October 2006

Jackson's method for separating death and emigration has been studied by computer simulation. In general this method seems to be quite effective in producing nearly unbiased survival estimates. However, the correction can cause a substantial increase in the variance of these estimates.
A new method to control houseflies, Musca domestica, at waste disposal sites
Authors: Imai Chobei
Published: October 2006

Investigation was carried out from 1976 to 1979 to establish a new control system against the houseflies, Musca domestica, at a sea‐filling waste disposal site in Osaka Bay, Japan.

Field surveys showed that the garbage was favorble for the fly breeding for 20–30 days after being disposed, while the sewage sludge and the ash from incinerated refuse were unfavorable. Comparing the fly density at the site to the reported cases of the public complaints in the urban area near to the site, a complaint threshold density of the flies at the site was estimated. Then, a control threshold density was assumed from the complaint threshold density and the reproductive rate of the housefly population. Several insecticides, as well as a surface active agent, polyoxyethylene lauryl ether (PEL), were found effective for the temporary suppression of the fly density.

Based on the results obtained, the following control system was worked out. 1) Refuse is disposed onto the same area as other inorganic wastes to deteriorate the capacity of breeding sources. 2) The fly density is examined on newly disposed refuse almost everyday by landfill operators. 3) PEL is sprayed when the density slightly exceeds the control threshold density. If the density increases rather higher, insecticide should be used. 4) The disposed refuse is covered with soil or other inorganic wastes on every weekend or every other weekend by 15 cm thickness.

Success in both fly control and reduction of the amounts of insecticides sprayed was achieved by a field application of this new control system.
A new method for describing predator‐prey relations in discontinous environments
Authors: Fujita Kazuyuki
Published: October 2006

I propose a new method for anlysing predatorprey interactive systems in discontinuous environments. The basic index used here is a generalized version ofLloyd's (1967) “interspecies mean crowding”, which is defined as the number of individuals of one species existing in a given patch per that of the other species in either the same or different patches at either the same or different times. Four indices are derived from different combinations of the numbers of the prey and the predator in habitat patches. Then, the correlation coefficients between the numbers of individuals in patches in both different locations and times are derived by modifying the above new indices. Using this technique, dynamical changes of the joint distributions of the numbers of predators and prey which reflect variation in local conditions, can readily be described. As an example, this method was applied to an analysis of the outcomes of a multi‐patch version of theLotka‐Volterra model of predator‐prey interactions.
Sampling statistics for Panonychus ulmi (Koch) (Acarina, Tetranychidae) and Tetranychus urticae Koch (Acarina, Tetranychidae) feeding on apple trees
Authors: Zahner Ph. , Baumgaertner J.
Published: October 2006

The distribution of Panonychus ulmi (Koch) and Tetranychus urticaeKoch as observed in Swiss apple orchards was analyzed in a multi‐stage sampling procedure. Based on the variance‐mean relationship (Taylor, 1961) a transformation of mite counts was made. Major sources of variation were found in between‐tree and between‐crown level differences. In usingBliss andOwen's (1958) method the negative binomial model was concluded to be appropriate for the description of the P. ulmi but not for the T. urticae distribution. HenceCroft's et al. (1976) sampling statistics was recalculated for P. ulmi only. The mean crowding index (Lloyd, 1967) was linearly related (Iwao, 1968) to the mean for P. ulmi and to a less extent for T. urticae that was found in much lower density range. Based on the mean crowding statistics a sampling program afterKuno, (1976) is proposed for both species. Some differences between the sampling plans and their applicability are discussed.
Resource allocation and time budgeting in adults of the cockroach, Periplaneta americana: The interaction of behaviour and metabolic reserves
Authors: Rollo C. David
Published: October 2006

Activity (to food, water and shelter) and resource allocation (mass budget, and size of various body components) were examined in populations of adult Periplaneta americana subjected to periods of starvation or sugar feeding. Following 13 days of starvation, roaches ate 5 times their normal daily ration and feeding required about 20 days to return to pre‐starvation levels. When sucrose was substituted for the usual dog‐food diet for 13 days, there was also a large increase in feeding initially. When the dog food was re‐established, however, there was very little feeding for about one week. Although reproduction was markedly curtailed by starvation, females fed sucrose continued reproducing for at least 59 days. The results suggested that the roaches were mainly energy limited.

Although the consumption of roaches was strongly affected by reserve depletion, eating was a small component of the time budget, and overall activity was relatively unchanged by starvation or sugar‐feeding. There was a slight decrease in activity during starvation, but the circadian pattern remained unchanged. Females carrying oöthecae were highly active and were apparently attracted to food (even though they ate little). Thus the activity of the population was dominated by circadian rhythmicity and the reproductive cycle.
Why do Luehdorfia butterflies lay eggs in clusters?
Authors: Itô Yosiaki , Tsubaki Yoshitaka , Osada Masaru
Published: October 2006

Luehdorfia butterflies lay eggs in clusters. Clones of their host plants (Asiasarum and Heterotropa) are distributed pacthily among the understory of deciduous forests. Groups of Luehdorfia larvae often exhaust the clones and may wander over the forest floor seeking new clones. The highest mortality observed is during this wandering period. To elucidate why Luehdorfia butterflies lay eggs in clusters, a simulation experiment was made for hypothetical populations which lay eggs in clusters or singly. Field data on larval mortality, consumption, density of host clones and leaf weight for Luehdorfia japonica were incorporated into the model. The predictions of the simulation were: (1) When the egg density is low, the single egg type could leave many more pupae than the egg clustering type, but when the egg density is high, the former might leave smaller number of pupae than the latter; and (2) There are optimal sizes of egg clusters for different egg densities and the optimal size becomes larger as the egg density increased.
Ecology of the fiddler crab Uca (Thalassuca) vocans vocans (Linnaeus) (Decapoda: Ocypodidae) I. Daily activity in warm and cold seasons
Authors: Nakasone Yukio
Published: October 2006

Field observations on the behaviour of Uca (Thalassuca) vocans vocans were made in the estuary of the Okukubi river, Okinawa Island.

The formation of the feeding aggregation of wandering individuals or drove was found in warm seasons above an average monthly air temperature 20°C from April to early November, while the aggregation was little observed in cold seasons below the temperature from the middle of November to March.

The members of the aggregation tended to move down from the upper levels of burrow area, rather than lower levels. This may be related to the richness of organic matters in the substratum of the lower levels as compared with the upper levels. The feeding aggregation was mostly composed of males, but in June females were numerously seen and its peak occurred in June. It suggested that the peak in June is related to both feeding and copulation.

Behaviour different from warm seasons was observed in cold seasons. When feeding on surface soil or Enteromorpha the crabs carried a mass of surface soil or the alga into their burrow. It was though that this behaviour was related to the storage of food.

It seems likely that the crabs maintain the population by the formation of the aggregation of wandering feeders in warm seasons when there are no algae and by feeding abundant algae as well as surface soil or by storing up food in good weather for bad one in cold seasons.
Foraging strategy of a non‐omniscient predator in a changing environment (II) model with two data windows and a relative comparison criterion
Authors: Inoue Tamiji
Published: October 2006

The model with two data windows and the relative comparison criterion (SRC) is proposed based on a Dynamic Programming problem. The model deals with predators whith remember separately the profitability of each patch and visit patches repeatedly. The model predator can remember foraging results that have occurred within the duration of memory (Dm). But when the number of foraging results in one patch exceeds the capacity of the memory chamber (Cm), older results are deleted from memory. Cm is the short data window for patches searched recently and Dm is the long one for patches searched in the past, but not recently. The model predator always searches at the patch with the highest estimation of profitability.

The validity of SRC was checked by the experiment with great tits ofSmith andSweatman (1974). SRC could describe satisfactorily weil the experimental result that great tits at first searched almost uniformly and then concentrated their foraging efforts to good patches but they could not detect the new good patch after changes in food distribution. These analyses showed that great tits did not forage in an optimal manner in the experimental conditions ofSmith andSweatman (1974).

Differences of SRC from the exploration and exploitation model ofKrebs et al. (1978) and from the model with one data window and the absolute criterion (SAC) of Inoue (1983) were discussed to show characteristics of the two extreme strategies for sampling the patchy environment.
Estimation of prey consumption of a mantid, Paratenodera angustipennis (S.) in a natural habitat
Authors: Matsura Toshiaki , Nagai Shinichi
Published: October 2006

Using a relationship between prey consumption and growth rate, field prey consumption of adults of Paratenodera angustipennis (S.) in a paddy field was estimated. Since a great number of grasshoppers (Oxya japonica) lived in the research area and the mantids had frequently eaten O. japonica, we presumed that they consumed only O. japonica. As a result, it was estimated that average prey consumptions for 6 days were 406 mg for the females and 23 mg for the males. From the result of this estimation and the feeding rhythm of the mantids, it is concluded that each female captured one grasshopper on average every a few days.

By comparing this actual feeding level of P. angustipennis with those of other predacious arthropods, characteristics of P. angustipennis as a predator were discussed.
Variation due to maternal age in the onion root maggot, Hylemya antiqua (Meigen)
Authors: Goth G. J. , Wellington W. G. , Contant H. Y.
Published: October 2006

A variety of characteristics were studied in populations of the onion root maggot, Hylemya antiqua, to determine the extent to which the age of the female producing a batch of eggs might affect heterogeneity in her offspring.

Early‐born offspring were found to be reproductively most successful. They had the longest mean expectation of life, a relatively low mortality rate into mid‐life, the highest average fecundity, the highest mean rate of egg production, and they produced the highest percentage of female offspring. On the other hand, mid‐born offspring were hardiest. They also had a long mean expectation of life, comparable to that for early‐born offspring but, in addition, they had the lowest sustained mortality rate and the greatest ability to survive food stress. Their robustness may have been acquired at the expense of certain reproductive capabilities however, in that their average fecundity was lower than their early‐born siblings', and their rate of egg production was more variable. Late‐born offspring were the most mortality‐prone and the least fecund, but they had the shortest mean generation time. These differences must be evaluated in terms of their effects on the rate of natural increase and on population growth.

Maternal age was found to influence pupal size, although the provenance groups differed significantly from each other and, in fact, showed opposite trends within their respective cohort groups. Size itself, and the ability of a species to alter the size at which it pupates, may be characteristics which have evolved to fit a specific set of environmental conditions.
The effects of food and density of the movement of Arion ater and Ariolimax columbianus (Pulmonata: Stylommatophora) between habitats
Authors: Hamilton Peter A. , Wellington William G.
Published: October 2006

Experiments were conducted to determine if slug density, or food quantity and quality could cause dispersal by slugs. Arion ater dispersed quickly from overcrowded areas, where high mortality was incurred by this species. Poor food conditions, caused more dispersal than good food conditions, but food had no effect on the mortality of A. ater. Neither food nor density factors had significant effects on the dispersal of Ariolimax columbianus. However, more A. columbianus died in the high‐ than low‐density treatments. A. columbianus mortality was unaffected by the food factor. Dispersing Arion were heavier than non‐dispersers, but there was no difference between the weights of dispersing and non‐dispersing Ariolimax. There were significant seasonal changes in the dispersal rate, mortality and weight of dispersing Arion, whereas only the mortality of Ariolimax changed significantly during the experiments.

Since Arion ater did not markedly reduce its activity during unsuitable weather it was able to leave areas of poor food and high slug density fairly rapidly. Ariolimax columbianus' large size allowed it to remain inactive during unfavourable weather and permitted this species to be relatively unresponsive to the experimental treatments.
The effects of age and weather on egg laying in Danaus plexippus L. (Lepidoptera: Danaidae)
Authors: Zalucki Myron P.
Published: October 2006

The effects of age and weather conditions on egg laying in D. plexippus were determined for caged females. Age (measured in physiological time), temperature and solar radiation influence egg laying in this species of butterfly. An algorithm taking these factors into account in presented and accounts for 88% of the daily variation in egg laying. Caged D. plexippus begin to lay eggs six—seven days after emergence, peak egg production (about 60 eggs/♀) occurs about 15 days later. Females continue to lay eggs throughout their adult life, which in a flight cage was about 40 days. This egg laying pattern is compared with other published fecundity schedules. The effect and importance of a female being prevented from laying her eggs, on her life‐time egg production, is also discussed.
Optimal clutch size of the chestnut gall‐wasp, Dryocosmus kuriphilus yasumatsu (Hymenoptera: Cynipidae)
Authors: Kato Kazutaka , Hijii Naoki
Published: October 2006

Optimal clutch size of the chestnut gall‐wasp, Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), was examined in galls on wild and resistant chestnut trees in 1988 and 1989. The rate of escape success of newly‐emerged adults from galls was an average of 60%, irrespective of cell numbers per gall. Dry mass per cell of a gall (as an index of nutritive condition) decreased with increasing cell number per gall, but was proportional to the mean number of mature eggs of new adults per gall. The number of cells per gall that occurred most frequently did not agree with that attained by the maximum survival rate from young larva to adult emergence of the gall‐wasp. This discrepancy was examined from the viewpoint of three factors: 1) quality of offspring, 2) defensive response of the host plant causing mortality of the gall‐wasp before cell formation, and 3) fitness per gall vs. fitness per egg. It is concluded that the third factor is most likely to be the one best in explaining the discrepancy.
Life table analysis of the green rice leafhopper, Nephotettix virescens (distant) (Hemiptera: Cicadellidae), and efficient vector of rice tungro disease in asynchronous rice fields in Indonesia
Authors: Aryawan I Gusti Ngurah , Widiarta I Nyoman , Suzuki Yoshito , Nakasuji Fusao
Published: October 2006

Population dynamics of Nephotettix virescens was studied in 17 paddy fields transplanted at intervals of about 1 month in 1988–1990. The adult density was highest either in the immigrant or the 1st generation and sharply decreased to the 2nd generation. The survival rate of the 1st generation was lowest in the transition season when areal population density increased. Key factor analysis revealed that the nymphal and adult mortality of the 1st generation (kn) was the principal source of population fluctuations. No significant correaltion was found between kn and natural enemy density, natural enemy density/healthy egg density, or the precipitation during the nymphal period. On these bases adult emigration was suspected to be the key factor. Areal population build‐up of N. virescens in the transition season was considered to occur as a result of increasing immigration to young stages of rice.
Pollination and factors limiting fruit set of chasmogamous flowers of an amphicapric annual, Polygonum thunbergii (Polygonaceae)
Authors: Momose Kuniyasu , Inoue Tamiji
Published: October 2006

We observed phenology and insect visitors of chasmogamous flowers of an amphicarpic annual, Polygonum thunbergii (Polygonaceae) in Kyoto, Japan, and clarified limiting factors for fruit set by bagging and hand‐pollination experiments. Flowering season was one month from late September. Flowers were visited by various insect groups (total 30 families and 64 species) and effective pollinators were lower bees (Halictidae) and wasps (Vespidae) in the early flowering season, and middle‐sized flies (Syrphidae and Calliphoridae) in the later season. Nectar was secreted at a constant rate (0.013mg sugar/hour) throughout a day and >90% of it was consumed by insects. The average number of flowers per ramet was 122, of which 95% were pollinated in the natural conditions. Bagging experiments showed that 47% of flowers were self‐pollinated even under no pollinator visits. Despite of a high probability of cross pollination, the probability of fruit set within the ramet was 0.30 due to resource limitation. We discussed possible adaptive significance of cleistogamous flowers under the condition that seeds could be produced by chasmogamous flowers through self‐pollination even under pollinator limited conditions.
Comparative analysis of population characteristics of the brown planthopper, Nilaparvata lugens stål, between wet and dry rice cropping seasons in West Java, Indonesia
Authors: Sawada Hiroichi , Kusmayadi Ayi , Gaib Subroto S. W. , Suwardiwijaya Edi , Mustaghfirin
Published: October 2006

Population dynamics of the brown planthopper (BPH),Nilaparvata lugens Stål, were investigated in paddy fields in the coastal lowland of West Java, Indonesia, where rice is cultivated twice a year, in the wet and dry cropping seasons. Distinct differences in the basic features of population dynamics were detected between the two rice cropping seasons: (1) In the wet season, BPH populations multiplied rapidly in the period from initial to peak generation, reaching quite often the destructive level despite the low density of initial immigrants. However, in the dry season, the population growth rate and the peak population density were much lower than those in the wet season. The abundance of natural enemies such as arthropod predators played a major role in determining such a difference in seasonal population development. (2) The density at the peak generation or the occurrence of outbreaks in each field was predictable in the wet season with fairly high accuracy on the basis of the density at the initial or previous seasonal generations. In the dry season, however, the rate of population growth and the peak population density widely varied among the fields depending on the water status in each field. (3) Density‐dependent processes to regulate the population density were detected in both cropping seasons. In the wet season, the regulatory processes were only detected in such high densities as cause the considerable deterioration of host plants, which suggested that the processes were largely attributable to intra‐specific competition. In the dry season, however, the regulatory processes operated at a much lower density in the earlier stages of the crops. The results of an analysis of adult longevity or residence period suggested that the density‐dependent dispersal of macropterous adults played an important role in stabilizing the population fluctuation among the fields in the early dry season.
Structural MRI discriminates individuals with Mild Cognitive Impairment from age‐matched controls: A combined neuropsychological and voxel based morphometry study
Authors: Trivedi Mehul A. , Wichmann Allison K. , Torgerson Britta M. , Ward Michael A. , Schmitz Taylor W. , Ries Michele L. , Koscik Rebecca L. , Asthana Sanjay , Johnson Sterling C.
Published: October 2006

Background

Several previous studies have reported that amnestic mild cognitive impairment (aMCI), a significant risk factor for Alzheimer's disease (AD), is associated with greater atrophy in the medial temporal lobe (MTL) and posterior cingulate gyrus (PCG).

Method

In the present study, we examined the cross‐sectional accuracy (i.e., the sensitivity and specificity) of voxel‐based morphometry (VBM) in discriminating individuals with MCI (n = 15) from healthy age‐matched controls (n = 15). In addition, we also sought to determine whether baseline GM volume predicted aMCI patients that converted to AD from those that did not approximately 2 years after the baseline visit.

Results

MCI patients were found to display significantly less GM volume in several hypothesized regions including the MTL and PCG relative to the age‐matched controls (p < 0.01). Logistic regression analysis and receiver operating characteristic (ROC) curves for GM volume in the anterior MTL and PCG revealed high discriminative accuracy of 87%. By contrast, baseline GM volume in anterior MTL and PCG did not appear to be sensitive to changes in clinical status at the follow‐up visit.

Conclusion

These results suggest that VBM might be useful at characterizing GM volume reductions associated with the diagnosis of aMCI.
The influence of 3,4-dimethylpyrazole phosphate and dicyandiamide on reducing nitrate accumulation in spinach under Mediterranean conditions
Authors: IRIGOYEN IGNACIO , LAMSFUS CARMEN , APARICIO-TEJO PEDRO , MURO JULIO
Published: October 2006

The European Union has limited the maximum nitrate (NO3−) content allowed for industrial processed spinach (Spinacia oleracea L.) to 2000 mg/kg fresh weight in order to avoid human pathologies associated with uptake of high amounts of nitrate. Nitrification inhibitors (NIs) 3,4-dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD) allow changing of the molecular form (NH4+ or NO3−) in which soil mineral N is available for plants. Enhancing ammonium nutrition has successfully reduced the amount of nitrate accumulated in plants in hydroponic culture. Therefore, fertilizers containing NIs have been proposed to reduce nitrate accumulated by vegetables grown in field conditions. Basammon Stabil® (BS) and Entec 26®-(E26) are commercial fertilizers containing DCD and DMPP respectively. In the present paper, the effect of applying ammonium sulphate nitrate (ASN), BS and E26 at three rates (0, 150 and 250 kg N/ha) to spinach crops cultivated under Mediterranean growing conditions for industrial processing is analysed. During 1998 and 1999, eight field split-plot trials with four replicates were carried out in the Ebro Valley, northern Spain, during different seasons and with various soil types. The fertilizer effects were influenced by the season and the type of soil. In spring, fertilizers containing NIs increased the mineral N (Nmin) in the soil and greatly reduced nitrate accumulation in the crop. In autumn, with less solar radiation, the nitrate accumulation was more than 2000 mg/kg fresh weight on many occasions and the effect of NIs was smaller. The present paper concluded that, under Mediterranean growing conditions, DCD can reduce nitrate accumulation in spinach between 18 and 61% and DMPP between 33 and 84%, without reducing yield or changing other quality characteristics. NIs are especially useful in the spring, when soil temperature is low and solar radiation interception by the crop is high.
Reflection of an electron beam by a photon mirror
Authors: MENDONÇA J. T. , SILVA L. O. , BINGHAM R.
Published: October 2006

A new configuration for the laser accelerator is proposed, which is inspired by the relativistic photon mirror effect. The material mirror is replaced here by an intense laser pulse, acting as a photon mirror for the incoming charged particles. A sufficient condition for particle reflection at such a photon mirror is established and three types of particle trajectories are described. A snow-plow acceleration regime is identified and quantitatively defined. Production of intense radiation bursts by the charged particle beam during the reflection process is also demonstrated.
Ovarian hormones and binge eating in bulimia nervosa
Authors: EDLER CRYSTAL , LIPSON SUSAN F. , KEEL PAMELA K.
Published: October 2006

Background. Symptom fluctuation in bulimia nervosa (BN) is related to menstrual cycle phase. However, the relationship between bulimic symptoms and ovarian hormones (estrogens and progesterone) has not been examined directly in women with BN.

Method. Regularly menstruating women with DSM-IV BN (n=9) and regularly menstruating controls (n=8) collected hormone samples and recorded mood and bulimic symptoms daily for 35 consecutive days. Estradiol and progesterone were measured by radioimmunoassay. Within-subject analyses examined prospective longitudinal associations between changes in ovarian hormones and changes in binge frequency in women with BN. Analyses controlled for the possible influence of negative affect on binge frequency as well as the influence of progesterone when examining estradiol associations and the influence of estradiol when examining progesterone associations. Between-subject analyses examined whether women with BN were more likely to have disrupted hormonal profiles than controls.

Results. Increases in binge eating were significantly associated with both decreases in estradiol and increases in progesterone in BN women with intact menstrual cycles. Although BN women were more likely to have disrupted hormone profiles than controls, this difference did not reach statistical significance, and mean estradiol and progesterone levels did not differ between bulimic and control groups.

Conclusions. The results are consistent with those from experimental animal studies and suggest that decreases in estradiol and increases in progesterone may contribute to increases in binge eating. Ovarian hormone function represents a promising candidate for unraveling the neurobiological mechanisms of binge eating.
DSM-IV alcohol dependence: a categorical or dimensional phenotype?
Authors: HASIN DEBORAH S. , LIU XINHUA , ALDERSON DONALD , GRANT BRIDGET F.
Published: October 2006

Background. Etiologic research on complex disorders including alcohol dependence requires informative phenotypes. Information is lost when categorical variables represent inherently dimensional conditions. We investigated the validity of DSM-IV alcohol dependence as a dimensional phenotype by examining evidence for linearity and thresholds in associations with validating variables.

Method. Current drinkers in the National Longitudinal Alcohol Epidemiologic Survey (NLAES) (n=18352) and National Epidemiologic Survey of Alcohol and Related Conditions (NESARC) (n=20836) were analyzed. Validating variables included family alcoholism, early-onset drinking, and alcohol treatment. Logistic or Poisson regression modeled the relationships between the validating variables and dependence in categorical, dimensional or hybrid forms, with severity defined as number of current DSM-IV alcohol-dependence criteria. Wald tests assessed differences between models.

Results. No evidence was found for boundaries between categories. Instead, the association of alcohol dependence with the validating variables generally increased in linear fashion as the number of alcohol-dependence criteria increased. For NLAES models of family alcoholism, early-onset drinking and treatment, the lines had zero intercepts, with slopes of 0·18, 0·27, 0·70, respectively. For NESARC models of family history and early-onset drinking, the zero intercept lines had slopes of 0·20, 0·33, and 0·77, respectively. Wald tests indicated that models representing alcohol dependence as a dimensional linear predictor best described the association between dependence criteria and the validating variables.

Conclusions. The sample sizes allowed strong tests. Diagnoses are necessary for clinical decision-making, but a dimensional alcohol-dependence indicator should provide more information for research purposes.
The architecture and function of the light-harvesting apparatus of purple bacteria: from single molecules to in vivo membranes
Authors: Cogdell Richard J. , Gall Andrew , Köhler Jürgen
Published: October 2006

1. Introduction 229

2. Structures 234

2.1 The structure of LH2 234

2.2 Natural variants of peripheral antenna complexes 242

2.3 RC–LH1 complexes 242

3. Spectroscopy 249

3.1 Steady-state spectroscopy 249

3.2 Factors which affect the position of the Qy absorption band of Bchla 249

4. Regulation of biosynthesis and assembly 257

4.1 Regulation 257

4.1.1 Oxygen 257

4.1.2 Light 258

4.1.2.1 AppA: blue-light-mediated regulation 259

4.1.2.2 Bacteriophytochromes 259

4.1.3 From the RC to the mature PSU 261

4.2 Assembly 261

4.2.1 LH1 262

4.2.2 LH2 263

5. Frenkel excitons 265

5.1 General 265

5.2 B800 267

5.3 B850 267

5.4 B850 delocalization 273

6. Energy-transfer pathways: experimental results 274

6.1 Theoretical background 274

6.2 ‘Follow the excitation energy’ 276

6.2.1 Bchla→Bchla energy transfer 277

6.2.1.1 B800→B800 277

6.2.1.2 B800→B850 278

6.2.1.3 B850→B850 279

6.2.1.4 B850→B875 280

6.2.1.5 B875→RC 280

6.2.2 Car[harr ]Bchla energy transfer 281

7. Single-molecule spectroscopy 284

7.1 Introduction to single-molecule spectroscopy 284

7.2 Single-molecule spectroscopy on LH2 285

7.2.1 Overview 285

7.2.2 B800 286

7.2.2.1 General 286

7.2.2.2 Intra- and intercomplex disorder of site energies 287

7.2.2.3 Electron-phonon coupling 289

7.2.2.4 B800→B800 energy transfer revisited 290

7.2.3 B850 293

8. Quantum mechanics and the purple bacteria LH system 298

9. Appendix 299

9.1 A crash course on quantum mechanics 299

9.2 Interacting dimers 305

10. Acknowledgements 306

11. References 307

This review describes the structures of the two major integral membrane pigment complexes, the RC–LH1 ‘core’ and LH2 complexes, which together make up the light-harvesting system present in typical purple photosynthetic bacteria. The antenna complexes serve to absorb incident solar radiation and to transfer it to the reaction centres, where it is used to ‘power’ the photosynthetic redox reaction and ultimately leads to the synthesis of ATP. Our current understanding of the biosynthesis and assembly of the LH and RC complexes is described, with special emphasis on the roles of the newly described bacteriophytochromes. Using both the structural information and that obtained from a wide variety of biophysical techniques, the details of each of the different energy-transfer reactions that occur, between the absorption of a photon and the charge separation in the RC, are described. Special emphasis is given to show how the use of single-molecule spectroscopy has provided a more detailed understanding of the molecular mechanisms involved in the energy-transfer processes. We have tried, with the help of an Appendix, to make the details of the quantum mechanics that are required to appreciate these molecular mechanisms, accessible to mathematically illiterate biologists. The elegance of the purple bacterial light-harvesting system lies in the way in which it has cleverly exploited quantum mechanics.
Greek measles epidemic strain, 2005–2006
Authors: GIOULA G. , PAPA A. , EXINDARI M. , MELIDOU A. , CHATZIDIMITRIOU D. , KARABAXOGLOU D. , ANTONIADIS A. , KYRIAZOPOULOU V.
Published: October 2006

The purpose of this work was the molecular study of the virus strain that caused the last measles outbreak in Greece. Twenty-four saliva specimens were obtained from selected patients serologically confirmed as measles cases between December 2005 and March 2006. Measles virus (MV) detection was performed by a nested RT–PCR. The 447-bp segment of the N gene of these MV strains was used for genotyping. The N gene sequences of the Greek MV strains were identical to each other, therefore a phylogenetic tree was constructed using one representative MV (ThesGRE/06). Our data show that the MV strain which caused the 2005–2006 outbreak in Greece belongs to genotype D6, and differs by 0·68% from the New Jersey D6 strain and by 5·5% from the MV vaccine strain Edmonston B (U03656) belonging to genotype A.
FETAL MANIPULATION FOR MANAGEMENT OF SHOULDER DYSTOCIA
Authors: GUREWITSCH EDITH D , ALLEN ROBERT H
Published: October 2006

Many authors assert that there is essentially nothing that can be done to better manage shoulder dystocia. They will point to injuries that have been proven to occur spontaneously and to a stable or even rising injury rate over the last decade and claim:

that the risk of injury cannot be reduced

that no manoeuvre has been proven superior to another or guaranteed to work in all circumstances

that the choice and sequence of specific shoulder dystocia manoeuvres beyond McRoberts' should be left to the discretion of the birth attendant

that the predominant concern during shoulder dystocia is its expedient resolution, by whatever means necessary, to avoid central nervous system damage or even death.
Neogloboquadrina pachyderma (dex. and sin.) Mg/Ca and δ18O records from the Norwegian Sea
Authors: Nyland Birgitte F. , Jansen Eystein , Elderfield Henry , Andersson Carin
Published: October 2006

Magnesium/calcium (Mg/Ca) records based on N. pachyderma (dex.) and N. pachyderma (sin.) from the last 1200 years have been retrieved from high‐resolution cores in the Norwegian Sea. Comparing temperatures inferred from Mg/Ca and the oxygen isotopic composition of calcite (δ18OC) with instrumental temperature records from Ocean Weather Ship Mike suggests that N. pachyderma calcifies during the summer season with an offset to oxygen isotope equilibrium of 0.6‰. In this region, summer temperatures below the thermocline are related to the winter season ventilation and breakdown of the seasonal thermocline; hence the deeper dwelling N. pachyderma (sin.) provides a winter season signal. Down‐core N. pachyderma (dex.) Mg/Ca temperatures display larger variance than observed in δ18OC temperatures record derived from the same morphotype. The smaller variance in the δ18OCN. pachyderma (dex.) temperatures is probably linked to salinity changes in the upper 50 m of the water column. The Mg/Ca temperature and δ18OC records are used to reconstruct changes in the oxygen isotopic composition of water (δ18Ow) during the last 1200 years. The reconstructed δ18OW records show variation within a realistic range, allowing the influence of other water masses than those present at the site today, and suggest that the Mg/Ca signal in morphotypes of N. pachyderma in the Norwegian Sea responds to changes in climatic parameters.
Large variations in Holocene solar activity: Constraints from 10Be in the Greenland Ice Core Project ice core
Authors: Vonmoos Maura , Beer Jürg , Muscheler Raimund
Published: October 2006

Cosmogenic radionuclides extracted from ice cores hold a unique potential for reconstructing past solar activity changes beyond the direct instrumental period. Taking the geomagnetic modulation into account, the solar activity in terms of the heliospheric modulation function can quantitatively be reconstructed in high resolution throughout the Holocene. For this period our results reveal changes in heliospheric modulation of galactic cosmic rays significantly larger than the variations reconstructed on the basis of neutron monitor measurements of galactic cosmic rays for the last 50 years. Moreover, the 10Be data from the Greenland Ice Core Project ice core as well as 14C support a high current solar activity. However, although the reconstruction of solar activity on long timescales is difficult, our result suggests that the modern activity state of the Sun is not that exceptional regarding the entire Holocene. This extended solar activity record provides the basis for further detailed investigations on solar and cosmic ray physics, as well as on solar forcing of the Earth's climate whose importance is suggested by increasing paleoclimatic evidences.
Temporal trends and variability of daily maximum and minimum, extreme temperature events, and growing season length over the eastern and central Tibetan Plateau during 1961–2003
Authors: Liu Xiaodong , Yin Zhi‐Yong , Shao Xuemei , Qin Ningsheng
Published: October 2006

Daily and monthly maximum and minimum surface air temperatures at 66 weather stations over the eastern and central Tibetan Plateau with elevations above 2000 m were analyzed for temporal trends and spatial variation patterns during the period 1961–2003. Statistically significant warming trends were identified in various measures of the temperature regime, such as temperatures of extreme events and diurnal temperature range. The warming trends in winter nighttime temperatures were among the highest when compared with other regions. We also confirmed the asymmetric pattern of greater warming trends in minimum or nighttime temperatures as compared to the daytime temperatures. The warming in regional climate caused the number of frost days to decrease significantly and the number of warm days to increase. The length of the growing season increased by approximately 17 days during the 43‐year study period. Most of the record‐setting months for cold events were found in the earlier part of the study period, while that of the warm events occurred mostly in the later half, especially since the 1990s. The changes in the temperature regime in this region may have brought regional‐specific impacts on the ecosystems. It was found that grain production in Qinghai Province, located in the area of prominent warming trends, exhibited strong correlations with the temperatures, although such relationships were obscured by the influence of precipitation in this arid/semiarid environment in juniper tree ring records. In western Sichuan Province under a more humid environment, the tree growth (spruces) was more closely related to the changing temperatures.
Analysis of snow in the 20th and 21st century Geophysical Fluid Dynamics Laboratory coupled climate model simulations
Authors: Déry Stephen J. , Wood Eric F.
Published: October 2006

We evaluate the representation of the 20th century Northern Hemisphere, North American, and Eurasian snow cover extent, frequency, and mass by the Geophysical Fluid Dynamics Laboratory coupled climate model, version 2 (CM2) and then explore the 21st century trends and changes in these quantities. The CM2 simulations of 20th century climate capture the seasonal cycle in Northern Hemisphere snow cover extent and produce a mean annual snow area of 25 × 106 km2 that equals the satellite‐based observations for the period 1973–2000. The simulated snow cover frequency and snow mass generally decline from north to south, but longitudinal gradients in these variables are also found. Snow mass over North America, especially during spring, is underestimated by CM2. Simulations of 21st century climate using three Intergovernmental Panel on Climate Change Special Report on Emission Scenarios reveal strong trends in Northern Hemisphere snow cover extent, frequency, and mass. These simulations suggest that the annual Northern Hemisphere mean snow cover extent (total snow mass) will decrease by 12 to 26% (20 to 40%) by 2100 from their 21st century mean values. Large declines in 21st century snow cover frequency (up to 50%) and snow mass (up to 100 kg m−2) arise during fall, winter, and spring over southern Canada and the northern United States, the Western Cordillera of North America, and western Eurasia compared to the 20th century CM2 simulations.
Phytoplankton mineralization in the tropical and subtropical Atlantic Ocean
Authors: Poulton A. J. , Sanders R. , Holligan P. M. , Stinchcombe M. C. , Adey T. R. , Brown L. , Chamberlain K.
Published: October 2006

Organic carbon fluxes to the deep ocean may be enhanced by association with ballast mineral material such as calcite and opal. We made simultaneous measurements of the upper ocean production of calcite (calcification), opal (silicification) and organic carbon (photosynthesis) at 14 stations between 42°S and 49°N in the Atlantic Ocean. These measurements confirm the light‐dependency of calcification and photosynthesis, and the substrate dependency of silicification. We estimate that mineralizing phytoplankton represent ∼5–20% of organic carbon fixation, with similar contributions from both coccolithophores and diatoms. Estimates of average turnover times for calcite and phytoplankton carbon are ∼3 days, indicative of their relatively labile nature. By comparison, average turnover times for opal and particulate organic carbon are ∼10 days. Rapid turnover of calcite suggests an important role for the plankton community in removing calcite from the upper ocean. Comparison of our surface production rates to sediment trap data confirms that ∼70% of calcite is dissolved in the upper 2–3 km, and only a small proportion of total organic carbon (<2%) reaches the deep ocean.
Time‐reversal imaging of seismic sources and application to the great Sumatra earthquake
Authors: Larmat Carene , Montagner Jean‐Paul , Fink Mathias , Capdeville Yann , Tourin Arnaud , Clévédé Eric
Published: October 2006

The increasing power of computers and numerical methods (like spectral element methods) allows continuously improving modelization of the propagation of seismic waves in heterogeneous media and the development of new applications in particular time reversal in the three‐dimensional Earth. The concept of time‐reversal (hereafter referred to as TR) was previously successfully applied for acoustic waves in many fields like medical imaging, underwater acoustics and non destructive testing. We present here the first application at the global scale of TR with associated reverse movies of seismic waves propagation by sending back long period time‐reversed seismograms. We show that seismic wave energy is refocused at the right location and the right time of the earthquake. When TR is applied to the Sumatra‐Andaman earthquake (26 Dec. 2004), the migration of the rupture from the south towards the north is retrieved. Therefore, TR is potentially interesting for constraining the spatio‐temporal history of complex earthquakes.