The role of behavior in the survival of Biomphalaria glabrata in biossays with the plant molluscicide Phytolacca dodecandra

This work examines the role of behavior in the survival of Biomphalaria glabrata exposed to 25, 50 75 and 100 mgl-1 of Phytolacca dodecandra. Time-lapse cinematography was used to quantify accurately the following parameters: (a) frequency of exits from the solution, (b) time spent out of the solution and (c) time elapsed until the first exit from the solution. These behavior patterns were statistically compared between surviving snails and those which later died. The proportion of surviving snails leaving the liquid medium was significantly higher than that of dying snails. In addition, the surviving group spent significantly more time out of the solution than the group which died, except for the 100 mgl-1 concentration. However, no significant difference was detected in the time elapsed until the first exit from the solution. It can be concluded that both the tendency to leave the P. dodecandra solutions, and the time spent out of them, contributed significantly to snail survival. Molluscicide bioassays should take into account the possibility that some behavior patterns of planorbids might contribute to the protection of the snails.

Studies on survival, biological activities and behavior of Biomphalaria glabrata, the host snail of Schistosomiasis, submitted to increased hydrostatic pressure: a technique

To study changes in survival, in biological activities and behavior of planorbids submitted to increased hydrostatic pressure, we developed a technique using two transparent chambers and a hydraulic piston. The apparatus permitted renewal of the liquid medium without substantial variations in pressure, thus eliminating excretion products and maintaining the desired O2 level and thereby permitting us to evaluate the effects of pressure independently of the occurrence of anoxia. Pressure was maintained without any contact of the liquid medium with compressed air, a situation which reproduced with relative fidelity what occurs in nature and assured the presence of the same amounts of gases in the two observation chambers (Control and Experimental). Biomphalaria glabrata was found to be able to survive at least 48 hours when submitted to 49.02 x 10**4 Pa (equivalent to a water depth of 48.8 m), continuing to day egg masses and showing few behavioral changes when compared with the control group.

Influence of larval and pupal products on the oviposition behavior of Aedes Fluviatilis (Lutz) (Diptera: Culicidae)

Several larval and pupal products of Aedes fluviatilis (Lutz) were tested for their influence on the oviposition behaviour of females of the same species. Significant (alfa = 0,05) atractiveness was shown by: larval water, previously containing 5 to 15 larvae/1,5 ml; larval water, preserved up to 38 days; evaporate and reconstructed larval water extracts up to 2 years after production and water filtered through fresh or dried ground larvae. hexanic larval water extracts and water filtered through fresh or dired ground pupae did not influence oviposition.

The causal relationship between Individual’s choice behavior and self-reported satisfaction: the case of residential mobility in the EU

One of the most persistent and lasting debates in economic research refers to whether the answers to subjective questions can be used to explain individuals’ economic behavior. Using panel data for twelve EU countries, in the present study we analyze the causal relationship between self-reported housing satisfaction and residential mobility. Our results indicate that: i) households unsatisfied with their current housing situation are more likely to move; ii) housing satisfaction raises after a move, and; iii) housing satisfaction increases with the transition from being a renter to becoming a homeowner. Some interesting cross-country differences are observed. Our findings provide evidence in favor of use of subjective indicators of satisfaction with certain life domains in the analysis of individuals’ economic conduct.

Maternal coping, appraisals and adjustment following diagnosis of fetal anomaly.

OBJECTIVE: So far, associations between appraisals, maternal adjustment and coping following diagnosis of fetal anomaly have not been investigated in women who continue with their pregnancy. METHOD: This study measured maternal coping and adjustment after and appraisal of a diagnosis of fetal anomaly in 40 mothers who had continued with their pregnancy using a cross-sectional questionnaire design. RESULTS: Based on retrospective reporting, 35% of participants met full diagnostic criteria for post-traumatic stress disorder after having received the diagnosis. Women were significantly more depressed (p < 0.001) and anxious (p < 0.001) and reported significantly less positive affect (p < 0.05) after having received the diagnosis in comparison to the time after childbirth. There were no significant differences between emotion-focused and problem-focused coping. Stressful life events, women's age, number of people providing support and problem-focused coping explained 57.6% of variance in anxiety and depression after childbirth. Satisfaction with social support, emotion-focused coping and problem-focused coping significantly explained 40.6% of variance in positive affect after childbirth. CONCLUSION: Following a prenatal diagnosis and for the remainder of their pregnancy, particular attention should be paid to older mothers, those experiencing additional stressful life events and those who are socially isolated, as these women may experience greater distress after childbirth.

Congenital heart disease in pregnancies complicated by maternal diabetes mellitus. An international clinical collaboration, literature review, and meta-analysis.

PURPOSE: Investigation of the incidence and distribution of congenital structural cardiac malformations among the offspring of mothers with diabetes type 1 and of the influence of periconceptional glycemic control. METHODS: Multicenter retrospective clinical study, literature review, and meta-analysis. The incidence and pattern of congenital heart disease in the own study population and in the literature on the offspring of type 1 diabetic mothers were compared with the incidence and spectrum of the various cardiovascular defects in the offspring of nondiabetic mothers as registered by EUROCAT Northern Netherlands. Medical records were, in addition, reviewed for HbA(1c) during the 1st trimester. RESULTS: The distribution of congenital heart anomalies in the own diabetic study population was in accordance with the distribution encountered in the literature. This distribution differed considerably from that in the nondiabetic population. Approximately half the cardiovascular defects were conotruncal anomalies. The authors' study demonstrated a remarkable increase in the likelihood of visceral heterotaxia and variants of single ventricle among these patients. As expected, elevated HbA(1c) values during the 1st trimester were associated with offspring fetal cardiovascular defects. CONCLUSION: This study shows an increased likelihood of specific heart anomalies, namely transposition of the great arteries, persistent truncus arteriosus, visceral heterotaxia and single ventricle, among offspring of diabetic mothers. This suggests a profound teratogenic effect at a very early stage in cardiogenesis. The study emphasizes the frequency with which the offspring of diabetes-complicated pregnancies suffer from complex forms of congenital heart disease. Pregnancies with poor 1st-trimester glycemic control are more prone to the presence of fetal heart disease.

International Corporate Taxation and U.S. Multinationals’ Behavior: an Integrated Approach

Using data from the International Revenue Service, this paper explores the effcts of corporate taxation on U.S. capital invested abroad and on tax planning practices (dividend payments, income shifting, and passive investment). The econometric analysis first indicates that investment is strongly influenced by average tax rates, with a magnified impact for particularly low-tax rates implying that the attractiveness of low-tax countries is not weakened by anti-deferral rules and cross-crediting limitations. Further explorations suggest that firms report higher profit and are less likely to repatriate dividends when they are located in low-tax jurisdictions. Firms also report higher Subpart F income in countries in which they shift their profit, suggesting that cross-crediting provides an incentive to shift passive income in low-tax countries and that passive investment can be an alternative strategy to minimize taxes when active investment opportunities are lacking. Finally, the paper estimates the role of effective transfer pricing regulation on income shifting activities using the quality of host countries' law enforcement. It appears that low degrees of law enforcement are associated with higher income-shifting.

Pregnancy Outcome Following Maternal Exposure To Statins: A Multicenter Prospective Study

Introduction: Statin use for the treatment of hypercholesterolemia in women of childbearing age is increasingly common. However, published data on pregnancy outcome after exposure to statins are scarce and conflicting. This contribution addresses the safety of exposure to statins during pregnancy.Method: In a multi-center (n = 11) observational, prospective study we compared the outcomes of 249 women exposed during the 1st trimester of pregnancy to simvastatin (n = 124), atorvastatin (n = 67), pravastatin (n = 32), rosuvastatin (n = 18), fluvastatin (n = 7) or cerivastatin (n = 1) with a control group exposed to agents known to be non-teratogenic (n = 249). The data were collected by members of the European Network of Teratology Information Services (ENTIS) during individual risk counseling between 1990 and 2009. Standardized procedures for data collection were used in each center.Results: The difference in the rate of major birth defects between the statin-exposed group and the control group was not statistically significant (4.0% vs. 2.7% OR 1.5; 95% CI 0.5-4.5, P = 0.44). The crude rate of spontaneous abortions (12.8% vs. 7.1%, OR 1.9, 95% CI 1.0-3.6, P = 0.04) was higher in the exposed group. However, after adjustment to maternal age and gestational age at initial contact, the difference became statistically insignificant. The rate of elective pregnancy-termination (8.8% vs. 4.4%, P = 0.05) was higher and the rate of deliveries resulting in live births was significantly lower in the statin exposed group (77.9% vs. 88.4%, P = 0.002). Prematurity was more frequent in exposed pregnancies (16.1% vs. 8.5%; OR 2.1, 95% CI 1.1-3.8, P = 0.02). Nonetheless, gestational age at birth (median 39 weeks, IQR 37-40 vs. 39 weeks, IQR 38-40, P = 0.27) and birth weight (median 3280 g, IQR 2835-3590 vs. 3250 g, IQR 2880-3600, P = 0.95) did not differ between exposed and non-exposed pregnancies.Conclusion: This study did not detect a clear teratogenic effect of statins. Its statistical power however is not sufficient to reverse the recommendation of treatment discontinuation during pregnancy. At most, the results are reassuring in case of inadvertent exposure.

Experimental evidence of a sunk–cost paradox: a study of pricing behavior in Bertrand–Edgeworth duopoly

A well–known implication of microeconomic theory is that sunk costs should have no effect on decision making. We test this hypothesis with a human–subjects experiment. Students recruited from graduate business courses, with an average of over six years of work experience, played the role of firms in a repeated price–setting duopoly game in which both firms had identical capacity constraints and costs, including a sunk cost that varied across experimental sessions over six different values. We find, contrary to the prediction of microeconomic theory, that subjects’ pricing decisions show sizable differences across treatments. The effect of the sunk cost is non–monotonic: as it increases from low to medium levels, average prices decrease, but as it increases from medium to high levels, average prices increase. These effects are not apparent initially, but develop quickly and persist throughout the game. Cachon and Camerer’s (1996) loss avoidance is consistent with both effects, while cost–based pricing predicts only the latter effect, and is inconsistent with the former.

Impact of a Cleft Lip and/or Palate on Maternal Stress and Attachment Representations.

Objective : The announcement, prenatally or at birth, of a cleft lip and/or palate represents a challenge for the parents. The purpose of this study is to identify parental working internal models of the child (parental representations of the child and relationship in the context of attachment theory) and posttraumatic stress disorder symptoms in mothers of infants born with a cleft. Method : The study compares mothers with a child born with a cleft (n  =  22) and mothers with a healthy infant (n  =  36). Results : The study shows that mothers of infants with a cleft more often experience insecure parental working internal models of the child and more posttraumatic stress symptoms than mothers of the control group. It is interesting that the severity or complexity of the cleft is not related to parental representations and posttraumatic stress disorder symptoms. The maternal emotional involvement, as expressed in maternal attachment representations, is higher in mothers of children with a cleft who had especially high posttraumatic stress disorder symptoms, as compared with mothers of children with a cleft having fewer posttraumatic stress disorder symptoms. Discussion : Mothers of children with a cleft may benefit from supportive therapy regarding parent-child attachment, even when they express low posttraumatic stress disorder symptoms.

A Theory of Wage Setting Behavior

Concerns for fairness, workers' morale and reciprocity infuence firms' wage setting policy. In this paper we formalize a theory of wage setting behavior in a simple and tractable model that explicitly considers these behavioral aspects. A worker is assumed to have reference-dependent preferences and displays loss aversion when evaluating the fairness of a wage contract. The theory establishes a wage-effort relationship that captures the worker's reference-dependent reciprocity, which in turn in uences the firm's optimal wage policy. The paper makes two key contributions: it identifies loss aversion as an explanation for a worker's asymmetric reciprocity; and it provides realistic and generalized microfoundation for downward wage rigidity. We further illustrate the implications of our theory for both wage setting and hiring behavior. Downward wage rigidity generates several implications for the outcome of the initial employment contract. The worker's reference wage, his extent of negative reciprocity and the firms expectations are key drivers of the propositions derived.

Comparison of the reproductive behavior between isolated Peckia chrysostoma (Wiedemann, 1830) and Adiscochaeta ingens (Walker, 1849) (Diptera: Sarcophagidae) females reared in laboratory

In both species, maintained under laboratory environmental conditions, anautogeny was comproved and all females that had free access to proteic source were fertiles. We obtained the following average values for Peckiachrysostoma: 59.7 ± 15.6 and 81.8 ± 15.4 days of longevity in the respective cases of free access and no access to proteic source, 21.4 ± 4.3 days of pre-larviposition period and 35.2 ± 16.5 days of larviposition period, 5.3 ± 1.8 larvipositions female with 7.0 ± 1.1 days of periodicity, 35.7 ± 6.1 larvae per larviposition leading to a total number of 183.8 ± 69.2 viable larvae per female and 94.8% ± 5.3% of productivity. The mean number of ovarioles per female was 56.4 ± 9.8, resulting in a reproductive potential of 63.3%. For Adiscochaeta ingens, the obtained average values were: 41.3 ± 6.3 and 52 ± 13.1 days of longevity in the respective cases of free access and no access to proteic source, 15.3 ± 1.7 days of pre-larviposition period and 21.5 ± 7.5 days of larviposition period, 3 ± 0.7 larvipositions per female with 10.4 ± 0.8 days of periodicity, 30.3 ± 8.2 larvae per larviposition leading to a total number of 78.5 ± 21.7 viable larvae per female and 90.1% ± 16% of productivity. The mean number of ovarioles per female was 54.6 ± 5.2, resulting in a reproductive potential of 55.5%. Within applied parameters, the values obtained for P. chrysostoma demonstrate its superior productivity in comparison with A. ingens

Epistasis and maternal effects in experimental adaptation to chronic nutritional stress in Drosophila.

Based on ecological and metabolic arguments, some authors predict that adaptation to novel, harsh environments should involve alleles showing negative (diminishing return) epistasis and/or that it should be mediated in part by evolution of maternal effects. Although the first prediction has been supported in microbes, there has been little experimental support for either prediction in multicellular eukaryotes. Here we use a line-cross design to study the genetic architecture of adaptation to chronic larval malnutrition in a population of Drosophila melanogaster that evolved on an extremely nutrient-poor larval food for 84 generations. We assayed three fitness-related traits (developmental rate, adult female weight and egg-to-adult viability) under the malnutrition conditions in 14 crosses between this selected population and a nonadapted control population originally derived from the same base population. All traits showed a pattern of negative epistasis between alleles improving performance under malnutrition. Furthermore, evolutionary changes in maternal traits accounted for half of the 68% increase in viability and for the whole of 8% reduction in adult female body weight in the selected population (relative to unselected controls). These results thus support both of the above predictions and point to the importance of nonadditive effects in adaptive microevolution.

Vigilance behavior of Pyrenean chamois (Rupicapra pyrenaica pyrenaica): Effect of sex and position in the herd

The Pyrenean chamois (Rupicapra pyrenaica pyrenaica) is a mountain-dwelling ungulate with an extensive presence in open areas. Optimal group size results from the trade off between advantages (a reduction in the risk of predation) and disadvantages (competition between members of the herd) of group living. In addition, advantages and disadvantages of group living may vary depending on the position of each individual within the herd. Our objective was to study the effect of central vs. peripheral position in the herd on feeding and vigilance behavior in male and female Pyrenean chamois and to ascertain if a group size effect existed. We used focal animal sampling and recorded social interactions when a focal animal was involved. With males, vigilance rate was higher in the central part of the group than at the periphery, probably due to a higher density of animals in the central part of the herd and a higher probability of being disturbed by conspecifics. With females, vigilance rate did not differ according to position in the herd. Females spent more time feeding than males, and males showed a higher frequency of the vigilance behavior than females. We did not observe a clear relationship between group size and vigilance behavior. The differences in vigilance behavior might be due to social interactions.

Adult abundance, biting behavior and parity of Anopheles aquasalis, Curry 1932 in two malarious areas of Sucre State, Venezuela

The principal vector of malaria in eastern Venezuela, Anopheles aquasalis, is exophagic and exophilic. Control using indoor insecticide house sprays has failed to lower the number of malaria cases. Therefore, studies were initiated in two villages of the eastern coastal state of Sucre to better understand this vector's biology and develop a more integrated control program. An. aquasalis was found to have a crepuscular biting behavior with a major peak at dusk and a minor peak at dawn. Mosquitos were collected more outdoors than indoors. Forty-seven percent of the biting took place before people went to bed (22:30 hr) and 69% of the mosquitos biting during this time period bite outdoors. Outdoor biting could be the reason why indoor spraying alone did not lower malaria cases. Seasonal abundance was greater in the rainy season compared to the dry season. Seasonal parous rates were high (78.3%-100%) and similar indoors and outdoors and between dry and wet season in Santa F e. In Guayana, the seasonal parity was lower (34.6%-42.2%) than Santa F e with indoor parity slightly higher than outdoors. Malaria cases were higher in Santa F e, but adult mosquito density was much lower than in Guayana. This difference could have been due to higher parity in Santa F e compared to Guayana. The greater distance to the nearest breeding site and presence of alternative hosts in Guayana can not be discounted as factors which contributed to the difference in malaria transmission between locations. We concluded that knowledge on seasonal occurrence, biting activity, resting behavior and breeding site location can be used to design a new control strategy for this vector.