Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon

USGS Publications Warehouse

McLeod, Pamela B.; Luoma, S.N.; Luthy, R.G.

2008-01-01

Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms. ?? 2008 American Chemical Society.

Comparative sensitivity of European native (Anodonta anatina) and exotic (Corbicula fluminea) bivalves to mercury

NASA Astrophysics Data System (ADS)

Oliveira, Patrícia; Lopes-Lima, Manuel; Machado, Jorge; Guilhermino, Lúcia

2015-12-01

Pollution is believed to be an important factor modulating the competition between exotic invasive bivalves and their native competitors. Thus, the objective of the present study was to compare the sensitivity of the European native Anodonta anatina and the exotic invasive species Corbicula fluminea to mercury, a ubiquitous environmental contaminant of high concern. In laboratory acute bioassays, adult organisms of both species were exposed independently to mercury for 96 h (31-500 μg/L). The criteria indicative of toxicity were mortality and biomarkers of oxidative stress and damage, neurotoxicity, and energy production changes. Mercury induced mortality in A. anatina (72 h-LC10 and 72 h-LC50 of 14.0 μg/L and 49.6 μg/L, respectively) but not in C. fluminea. The ability of C. fluminea to maintaining the shell closed for considerable periods of time when exposed to high concentrations of mercury and the effective activation (up to 63 μg/L) of mechanisms against the oxidative stress caused by mercury may have contributed to its relatively low sensitivity. In the range of concentrations tested, mercury had no significant effects on the other parameters analysed in C. fluminea. Overall, the findings of the present study, suggest that in real scenarios of competition between C. fluminea and A. anatina populations, the presence of mercury may modulate the process, acting in favour of the exotic species because it is less sensitive to this environmental contaminant than the native bivalve. The results of the present study highlight the need of further investigation on the effects of mercury on the competition between exotic invasive species and their native competitors, especially the effects potentially induced by long-term exposure to low concentrations of this metal, the mechanisms involved in the tolerance to mercury-induced stress, and the potential post-exposure recovery of both exotic invasive and native bivalves. This knowledge is most important for

Growth and overwinter survival of the Asiatic clam, Corbicula fluminea, in the St. Clair River, Michigan

USGS Publications Warehouse

French, John R. P.; Schloesser, Donald W.

1991-01-01

We report the discovery in April 1986 of the first population of Asiatic clam, Corbicula fluminea, known to occupy a lotic environment in the Laurentian Great Lakes system. This population occupied a 3.8 km long sandy shoal in the discharge plume of a steam-electric power plant on the St. Clair River (Michigan), the outflow of Lake Huron. Samples collected April 1986 to April 1987 revealed the growth of one-year-old Corbicula (1985 cohort) began after mid-May and ended by mid-November, while water temperatures were higher than 9°C. Maximum growth (0.78 mm wk-1) occurred between mid-August and mid-September, while water temperatures were about 16-23°C. We recorded a substantial overwinter mortality of the 1986 cohort, but not the 1985 cohort; this was particularly evident at sampling locations more remote from the heated discharge of the power plant, suggesting low water temperature wast the major mortality agent. The available information suggests low water temperature in the St. Clair River may limit the success of Corbicula in the river, including portions of populations inhabiting thermal plumes, by reducing growth, delaying the onset of sexual maturity and reproduction, and causing heavy overwinter mortality in the first year of life.

How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774) in a Neotropical reservoir?

PubMed

Paschoal, L R P; Andrade, D P; Darrigran, G

2015-01-01

Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure). The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS) (Minas Gerais, Brazil), in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2) placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point). We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m). The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years). These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation) may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native malacofauna in

Uptake and effects of the antimicrobial florfenicol, microplastics and their mixtures on freshwater exotic invasive bivalve Corbicula fluminea.

PubMed

Guilhermino, Lúcia; Vieira, Luís R; Ribeiro, Diogo; Tavares, Ana Sofia; Cardoso, Vera; Alves, Anabela; Almeida, José Manuel

2018-05-01

Microplastics and antimicrobials are widely spread environmental contaminants and more research on their toxicity is needed. The uptake and effects of the antimicrobial florfenicol, microplastics, and their mixtures on Corbicula fluminea were investigated. Bivalves were exposed for 96h to florfenicol (1.8 and 7.1mg/l), microplastics (0.2 and 0.7mg/l), or mixtures of the two substances. After 96h, all bivalves exposed to antimicrobial treatments had florfenicol in their body (e.g. 2±1μg/g). Microplastics were found in the gut, lumen of the digestive gland, connective tissue, hemolymphatic sinuses, and gills surface of animals. Florfenicol caused a significant inhibition of cholinesterase (ChE) activity (~32%). Animals exposed to 0.2mg/l of microplastics showed ChE activity inhibition (31%), and no other significant alterations. Mixtures caused feeding inhibition (57-83%), significant ChE inhibition (44-57%) and of isocitrate dehydrogenase activity, and increased anti-oxidant enzymes activity and lipid peroxidation levels. Overall, the results indicate that C. fluminea take up florfenicol and microplastics from the water and accumulated or at least retained it in their body for some time; both florfenicol (low ppm range) and microplastics (ppb range) were toxic to C. fluminea, with mixtures containing florfenicol and microplastics being more toxic. Thus, the risk of exposure and toxic effects of florfenicol to C. fluminea and other bivalves, and its predators increase in ecosystems contaminated with the antimicrobial and microplastics, as well as to humans consuming contaminated species from these ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Population dynamics of Corbicula fluminea (Müller, 1774) in mesohaline and oligohaline habitats: Invasion success in a Southern Europe estuary

USGS Publications Warehouse

Franco, J.N.; Ceia, F.R.; Patricio, J.; Thompson, John; Marques, J.C.; Neto, J.M.

2012-01-01

Due to its range expansion and potential ecological effects, Corbicula fluminea is considered one of the most important non-indigenous species (NIS) in aquatic ecosystems. Its presence since 2003 in the upstream area of Mondego estuary (oligohaline and mesohaline sectors) was studied during thirteen months, from December 2007 to December 2008. Monthly mean abundance and biomass ranged from 542 to 11142 individuals m-2 and 13.1–20.4 g Ash Free Dry Weight m-2, respectively. Populations of C.fluminea were composed mostly of juveniles, always present in extremely high densities compared to other estuarine ecosystems (e.g. Minho estuary) suggesting a continuous recruitment pattern. The hydraulic regime of the River Mondego favours the downstream colonization of the upper Mondego estuary by recruits produced upstream. However, salinity in these sectors of the estuary apparently neither favours growth nor the establishment of structured populations of this species. Other factors like contaminants and predation, which were not studied, could also contribute to the community structure observed.

Assessing the impact of lanthanum on the bivalve Corbicula fluminea in the Rhine River.

PubMed

Zhao, Liqiang; Liu, Lei

2018-06-04

Anthropogenic lanthanum predominantly derived from a point source has become an emerging contaminant in the Rhine River, but little is known about its ecotoxicological consequences on bivalve mollusks. A fundamental requirement of aquatic invertebrate adaptation and survival in stressful habitats is the maintenance of energy homeostasis. As such, the present study tested the impact of four dissolved La concentrations (0, 50, 100 and 200 μM) on the energy balance of the bivalve Corbicula fluminea in the Rhine River. Bivalves were collected at four sampling sites which were contaminated by La to different degrees, thereby allowing to understand the degree of their potential acclimation. With increasing exposure dose, shell and somatic growth (the most energetically expensive biological processes) decreased significantly in clams inhabited the control (uncontaminated) habitat; while less pronounced impacts were evident in all three contaminated sites. In particular, the latter showed virtually unaffected energy (glycogen and protein) reserves. An elucidation of shifts in the organismal energy budget may shed light on such improvement of growth performance. Irrespective of sampling sites, short-term exposure to La caused significant increases of oxygen consumption and ammonia excretion, indicating that the clams promoted their energy metabolism and thereby allocated more energy to essential physiological processes. Noteworthily, the clams originating from contaminated sites displayed virtually unaffected clearance rate, thereby being able to partially fulfill the increased energy demand and eventually alleviating the La-induced physiological interference. Taken together, findings of the present study demonstrate that whether, and to what extent, C. fluminea is able to sustain its energy homeostasis play a central role in the phenotypic plasticity and/or genetic adaptation in the face of anthropogenic La contamination in the Rhine River. Copyright © 2018 Elsevier B

Modelling the risk of mortality of Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae) exposed to different turbidity conditions.

PubMed

Avelar, W E P; Neves, F F; Lavrador, M A S

2014-05-01

The provision of sediment in rivers, due to erosion processes that occur in the environment, consists of a major source of pollution and alteration of the physicochemical conditions of water resources. In addition, the increase in water turbidity may cause siltation, dramatically impacting aquatic communities. Specifically considering the bivalve Corbicula fluminea (Müller, 1774), the aim of this study was to analyse the effect of exposure to different turbidity conditions of sediments, as a risk factor for the animals. For this purpose, a docking device was designed to ensure water circulation in a closed system and to maintain the desired levels of turbidity. Although C. fluminea can generally tolerate environmental changes in aquatic systems, an intolerance to high turbidity levels was experimentally observed, expressed by the mortality rate of the animals when exposed to conditions above 150 nephelometric turbidity units (NTU). This value was similar to the one recorded at study sites in the rivers Pardo (Serrana-SP-Brazil) and Mogi Guaçu (Porto Ferreira-SP-Brazil) during the rainy season. Using a logistic regression model, the experimental results were analysed and the observed mortality rates indicate that the exposure of the animals to turbidity levels above 150 nephelometric turbidity units (NTU), for periods longer than 120 hours, may be considered a probable cause of mortality for the species.

A real-time biomonitoring system to detect arsenic toxicity by valve movement in freshwater clam Corbicula fluminea.

PubMed

Chen, Wei-Yu; Jou, Li-John; Chen, Suz-Hsin; Liao, Chung-Min

2012-05-01

Arsenic (As) is the element of greatest ecotoxicological concern in aquatic environments. Effective monitoring and diagnosis of As pollution via a biological early warning system is a great challenge for As-affected regions. The purpose of this study was to synthesize water chemistry-based bioavailability and valve daily rhythm in Corbicula fluminea to design a biomonitoring system for detecting waterborne As. We integrated valve daily rhythm dynamic patterns and water chemistry-based Hill dose-response model to build into a programmatic mechanism of inductance-based valvometry technique for providing a rapid and cost-effective dynamic detection system. A LabVIEW graphic control program in a personal computer was employed to demonstrate completely the functional presentation of the present dynamic system. We verified the simulated dissolved As concentrations based on the valve daily rhythm behavior with published experimental data. Generally, the performance of this proposed biomonitoring system demonstrates fairly good applicability to detect waterborne As concentrations when the field As concentrations are less than 1 mg L(-1). We also revealed that the detection times were dependent on As exposure concentrations. This biomonitoring system could particularly provide real-time transmitted information on the waterborne As activity under various aquatic environments. This parsimonious C. fluminea valve rhythm behavior-based real-time biomonitoring system presents a valuable effort to promote the automated biomonitoring and offers early warnings on potential ecotoxicological risks in regions with elevated As exposure concentrations.

Long-Term Acclimation to Different Thermal Regimes Affects Molecular Responses to Heat Stress in a Freshwater Clam Corbicula Fluminea

NASA Astrophysics Data System (ADS)

Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.

2016-12-01

Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20-41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8-12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.

Inorganic mercury detection by valve closure response in the freshwater clam Corbicula fluminea: integration of time and water metal concentration changes.

PubMed

Tran, Damien; Fournier, Elodie; Durrieu, Gilles; Massabuau, Jean-Charles

2007-07-01

The objective of the present study was to monitor water-quality assessment by a biological method. Optimum dissolved inorganic mercury sensitivity in the freshwater bivalve Corbicula fluminea was estimated using a combined approach to determine their potentials and limits in detecting contaminants. Detection by bivalves is based on shell closure, a protective strategy when exposed to a water contaminant. To take the rate of spontaneous closures into account, stress associated with fixation by one valve in common valvometers was integrated, and the spontaneous rhythm was associated with daily activity. The response in conditions where the probability of spontaneous closing is the lowest was thus taken into account. To develop dose-response curves, impedance valvometry, in which lightweight impedance electrodes are applied to study free-ranging animals in low-stress conditions, also was used combined with a new analytical approach. The logistic regression dose-response curves take into account variations in both response time and metal concentration in water to significantly improve the methods aiming at determining the optimal sensitivity threshold response. This approach demonstrates that in C. fluminea, inorganic mercury concentrations under the range of 2.0 to 5.1 microg/L (95% confidence interval) cannot be detected within 5 h of addition.

Protein-Bound Polysaccharide from Corbicula fluminea Inhibits Cell Growth in MCF-7 and MDA-MB-231 Human Breast Cancer Cells.

PubMed

Liao, Ningbo; Zhong, Jianjun; Zhang, Ronghua; Ye, Xingqian; Zhang, Yanjun; Wang, Wenjun; Wang, Yuexia; Chen, Shiguo; Liu, Donghong; Liu, Ruihai

2016-01-01

A novel protein-bound polysaccharide, CFPS-1, isolated from Corbicula fluminea, is composed predominantly of mannose (Man) and glucose (Glc) in a molar ratio of 3.1:12.7. The polysaccharide, with an average molecular weight of about 283 kDa, also contains 10.8% protein. Atomic force microscopy, high-performance liquid chromatography, Fourier transform infrared spectroscopy, gas chromatography/mass spectrometry, and nuclear magnetic resonance spectroscopy analyses revealed that CFPS-1 has a backbone of 1,6-linked and 1,4,6-linked-α-D-Glc, which is terminated with a 1-linked-α-D-Man residue at the O-4 position of 1,4,6-linked-α-D-Glc, in a molar ratio of 3:1:1. Preliminary in vitro bioactivity tests revealed that CFPS-1 effectively and dose-dependently inhibits human breast cancer MCF-7 and MDA-MB-231 cell growth, with an IC50 of 243 ± 6.79 and 1142 ± 14.84 μg/mL, respectively. In MCF-7, CFPS-1 produced a significant up-regulation of p53, p21, Bax and cleaved caspase-7 and down-regulation of Cdk4, cyclin D1, Bcl-2 and caspase-7. These effects resulted in cell cycle blockade at the S-phase and apoptosis induction. In contrast, in MDA-MB-231, with limited degree of change in cell cycle distribution, CFPS-1 increases the proportion of cells in apoptotic sub-G1 phase executed by down-regulation of Bcl-2 and caspase-7 and up-regulation of Bax and cleaved caspase-7. This study extends our understanding of the anticancer mechanism of C. fluminea protein-bound polysaccharide.

Invasive zebra mussels (Driessena polymorpha) and Asian clams (Corbicula fluminea) survive gut passage of migratory fish species: implications for dispersal

USGS Publications Warehouse

Gatlin, Michael R.; Shoup, Daniel E.; Long, James M.

2013-01-01

The introduction and spread of invasive species is of great concern to natural resource managers in the United States. To effectively control the spread of these species, managers must be aware of the multitude of dispersal methods used by the organisms. We investigated the potential for survival through the gut of a migrating fish (blue catfish, Ictalurus furcatus) as a dispersal mechanism for two invasive bivalves: zebra mussel (Driessena polymorpha) and Asian clam (Corbicula fluminea). Blue catfish (N = 62) were sampled over several months from Sooner Lake, Oklahoma, transported to a laboratory and held in individual tanks for 48 h. All fecal material was collected and inspected for live mussels. Survival was significantly related to water temperature in the lake at the time of collection, with no mussels surviving above 21.1 C°, whereas 12 % of zebra mussels (N = 939) and 39 % of Asian clams (N = 408) consumed in cooler water survived gut passage. This research demonstrates the potential for blue catfish to serve as a dispersal vector for invasive bivalves at low water temperatures.

[Effects of eutrophication on distribution and population density of Corbicula fluminea and Bellamya sp. in Chaohu Lake].

PubMed

Deng, Daogui; Li, Hongyuan; Hu, Wanming; Zhou, Qiong; Guo, Longgen

2005-08-01

The investigation on the distribution an d population density of C. fluminea and Bellamya sp. in Chaohu Lake during September 2001 and September 2002 showed that in the west region of the lake where was seriously eutrophic, the density and biomass of C. fluminea were 5.1 ind. x m(-2) and 17.87 g x m(-2) in 2001, and 8.8 ind. x m(-2) and 47.29 g x m(-2) in 2002, while those of Bellamya sp. were 13.3 ind. x m(-2) and 45.45 g x m(-2) in 2001, and 3.8 ind. x m(-2) and 12.56 g x m(-2) in 2002, respectively. In the east region of the lake where was eutrophic, the density and biomass of C. fluminea were 23.8 ind. x m(-2) and 67.86 g x m(-2) in 2001, and 29.2 ind. x m(-2) and 96.18 g x m(-2) in 2002, while those of Bellamya sp. were 10.1 ind. x m(-2) and 32.00 g x m(-2) in 2001, and 9.4 ind. x m(-2) and 31.21 g x m(-2) in 2002, respectively. The density and biomass of C. fluminea and Bellamya sp. were declined with increasing eutrophication. In hypertrophic region, C. fluminea and Bellamya sp. were absent. The density and biomass of the two species were obviously higher in littoral than in pelagic region. The distribution type of C. fluminea was core-model, while that of Bellamya sp. was random. The correlation between the density and biomass of C. fluminea and Bellamya sp. and water depth was not significant (P > 0.05). The biomass of Bellamya sp. was negatively correlated with water TN (P < 0.01), NO3-N (P < 0.05), TP(P < 0.01) and PO4-P (P < 0.05), while that of C. fluminea only had a significantly negative correlation with PO4-P(P < 0.05). Compared with 1981, there was fewer C. fluminea in the lake nowadays. The effects of other environmental factors on the population distribution and growth of C. fluminea and Bellamya sp. were also discussed.

Direct and indirect effects of different types of microplastics on freshwater prey (Corbicula fluminea) and their predator (Acipenser transmontanus)

PubMed Central

Parnis, J. Mark; Browne, Mark A.; Serrato, Sebastian; Reiner, Eric J.; Robson, Matthew; Young, Thomas; Diamond, Miriam L.; Teh, Swee J.

2017-01-01

We examined whether environmentally relevant concentrations of different types of microplastics, with or without PCBs, directly affect freshwater prey and indirectly affect their predators. Asian clams (Corbicula fluminea) were exposed to environmentally relevant concentrations of polyethylene terephthalate (PET), polyethylene, polyvinylchloride (PVC) or polystyrene with and without polychlorinated biphenyls (PCBs) for 28 days. Their predators, white sturgeon (Acipenser transmontanus), were exposed to clams from each treatment for 28 days. In both species, we examined bioaccumulation of PCBs and effects (i.e., immunohistochemistry, histology, behavior, condition, mortality) across several levels of biological organization. PCBs were not detected in prey or predator, and thus differences in bioaccumulation of PCBs among polymers and biomagnification in predators could not be measured. One of the main objectives of this study was to test the hypothesis that bioaccumulation of PCBs would differ among polymer types. Because we could not answer this question experimentally, a bioaccumulation model was run and predicted that concentrations of PCBs in clams exposed to polyethylene and polystyrene would be greater than PET and PVC. Observed effects, although subtle, seemed to be due to microplastics rather than PCBs alone. For example, histopathology showed tubular dilation in clams exposed to microplastics with PCBs, with only mild effects in clams exposed to PCBs alone. PMID:29108004

Bioavailability and toxicity of metals from a contaminated sediment by acid mine drainage: linking exposure-response relationships of the freshwater bivalve Corbicula fluminea to contaminated sediment.

PubMed

Sarmiento, Aguasanta M; Bonnail, Estefanía; Nieto, José Miguel; DelValls, Ángel

2016-11-01

Streams and rivers strongly affected by acid mine drainage (AMD) have legal vacuum in terms of assessing the water toxicity, since the use of conventional environmental quality biomarkers is not possible due to the absence of macroinvertebrate organisms. The Asian clam Corbicula fluminea has been widely used as a biomonitor of metal contamination by AMD in freshwater systems. However, these clams are considered an invasive species in Spain and the transplantation in the field study is not allowed by the Environmental Protection Agency. To evaluate the use of the freshwater bivalve C. fluminea as a potential biomonitor for sediments contaminated by AMD, the metal bioavailability and toxicity were investigated in laboratory by exposure of clams to polluted sediments for 14 days. The studied sediments were classified as slightly contaminated with As, Cr, and Ni; moderately contaminated with Co; considerably contaminated with Pb; and heavily contaminated with Cd, Zn, and specially Cu, being reported as very toxic to Microtox. On the fourth day of the exposure, the clams exhibited an increase in concentration of Ga, Ba, Sb, and Bi (more than 100 %), followed by Co, Ni, and Pb (more than 60 %). After the fourth day, a decrease in concentration was observed for almost all metals studied except Ni. An allometric function was used to determine the relationship between the increases in metal concentration in soft tissue and the increasing bioavailable metal concentrations in sediments.

Oxidative stress and histological changes following exposure to diamond nanoparticles in the freshwater Asian clam Corbicula fluminea (Müller, 1774).

PubMed

Cid, Antonio; Picado, Ana; Correia, José Brito; Chaves, Rúben; Silva, Héber; Caldeira, Jorge; de Matos, António P Alves; Diniz, Mário S

2015-03-02

Recently, the scientific community became aware of the potential ability of nanoparticles to cause toxicity in living organisms. Therefore, many of the implications for aquatic ecosystems and its effects on living organisms are still to be evaluated and fully understood. In this study, the toxicity of nanodiamonds (NDs) was assessed in the freshwater bivalve (Corbicula fluminea) following exposure to different nominal concentrations of NDs (0.01, 0.1, 1, and 10 mg l(-1)) throughout 14 days. The NDs were characterized (gravimetry, pH, zeta potential, electron microscopy, and atomic force microscopy) confirming manufacturer information and showing NDs with a size of 4-6 nm. Oxidative stress enzymes activities (glutathione-S-transferase, catalase) and lipid peroxidation were determined. The results show a trend to increase in GST activities after seven days of exposure in bivalves exposed to NDs concentrations (>0.1 mg l(-1)), while for catalase a significant increase was found in bivalves exposed from 0.01 to 1.0 mg l(-1) following an exposure of 14 days. The histological analysis revealed alterations in digestive gland cells, such as vacuolization and thickening. The lipid peroxidation showed a trend to increase for the different tested NDs concentrations which is compatible with the observed cellular damage. Copyright © 2014 Elsevier B.V. All rights reserved.

Assessment of Lemna minor (duckweed) and Corbicula fluminea (freshwater clam) as potential indicators of contaminated aquatic ecosystems: responses to presence of psychoactive drug mixtures.

PubMed

Bourioug, Mohamed; Mazzitelli, Jean-Yves; Marty, Pierre; Budzinsky, Hélène; Aleya, Lotfi; Bonnafé, Elsa; Geret, Florence

2018-04-01

The pharmaceutical products are emerging pollutants continuously released into the environment, because they cannot be effectively removed by the wastewater treatment plants. In recent years, questions have been raised concerning the environmental risks related to these pollutants. The goal of this research was to evaluate the responses in Lemna minor after 7 days and in Corbicula fluminea after differing durations (1, 3, 7, and 19 days) of exposure to the psychoactive drug mixture (valproic acid, citalopram, carbamazepine, cyamemazine, hydroxyzine, oxazepam, norfluoxetine, lorazepam, fluoxetine, and sertraline) in different concentrations (0, 0 + ethanol, drug concentration (DC) 1 = river water concentration, DC2 = effluent concentration, and DC3 = 10× effluent concentration). In this aim, growth parameters of L. minor, gluthathione S-transferase (GSTs), catalase (CAT), ethoxyresorufin-O-deethylase (EROD) and/or gene expressions (pi-gst, cat, cytochrome P450 4 (cyp4), multidrug resistant 1 (mdr1), and superoxide dismutase (sod)) were measured. GST activities increased significantly in L. minor exposed to DC3, but no changes were found in CAT activity. In C. fluminea, EROD activity was induced significantly in both gill and digestive gland tissues after 3 days' exposure to DC3, while a GST increase was observed only in digestive gland tissues, suggesting that these pharmaceuticals induced an oxidative effect. Gene expression analysis revealed transient transcriptomic responses of cyp4, sod, and mdr1 under drug concentrations 2 or 3 and no change of expression for the other genes (cat and pi-gst) or condition (environmental drug concentration) tested. Finally, the data reported in this study represent important ecotoxicological information, confirming that this enzyme family (cyp4, sod, and mdr1) may be considered as a sensible and early indicator of exposure to drugs and emphasizing the involvement of selected genes in detoxification pathways.

Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)

USGS Publications Warehouse

Nichols, S. Jerrine; Black, M.G.

1994-01-01

There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.

A novel approach for acid mine drainage pollution biomonitoring using rare earth elements bioaccumulated in the freshwater clam Corbicula fluminea.

PubMed

Bonnail, Estefanía; Pérez-López, Rafael; Sarmiento, Aguasanta M; Nieto, José Miguel; DelValls, T Ángel

2017-09-15

Lanthanide series have been used as a record of the water-rock interaction and work as a tool for identifying impacts of acid mine drainage (lixiviate residue derived from sulphide oxidation). The application of North-American Shale Composite-normalized rare earth elements patterns to these minority elements allows determining the origin of the contamination. In the current study, geochemical patterns were applied to rare earth elements bioaccumulated in the soft tissue of the freshwater clam Corbicula fluminea after exposure to different acid mine drainage contaminated environments. Results show significant bioaccumulation of rare earth elements in soft tissue of the clam after 14 days of exposure to acid mine drainage contaminated sediment (ΣREE=1.3-8μg/gdw). Furthermore, it was possible to biomonitor different degrees of contamination based on rare earth elements in tissue. The pattern of this type of contamination describes a particular curve characterized by an enrichment in the middle rare earth elements; a homologous pattern (E MREE =0.90) has also been observed when applied NASC normalization in clam tissues. Results of lanthanides found in clams were contrasted with the paucity of toxicity studies, determining risk caused by light rare earth elements in the Odiel River close to the Estuary. The current study purposes the use of clam as an innovative "bio-tool" for the biogeochemical monitoring of pollution inputs that determines the acid mine drainage networks affection. Copyright © 2017 Elsevier B.V. All rights reserved.

The Asian clam Corbicula fluminea as a biomonitor of trace element contamination: Accounting for different sources of variation using an hierarchical linear model

USGS Publications Warehouse

Shoults-Wilson, W. A.; Peterson, J.T.; Unrine, J.M.; Rickard, J.; Black, M.C.

2009-01-01

In the present study, specimens of the invasive clam, Corbicula fluminea, were collected above and below possible sources of potentially toxic trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the Altamaha River system (Georgia, USA). Bioaccumulation of these elements was quantified, along with environmental (water and sediment) concentrations. Hierarchical linear models were used to account for variability in tissue concentrations related to environmental (site water chemistry and sediment characteristics) and individual (growth metrics) variables while identifying the strongest relations between these variables and trace element accumulation. The present study found significantly elevated concentrations of Cd, Cu, and Hg downstream of the outfall of kaolin-processing facilities, Zn downstream of a tire cording facility, and Cr downstream of both a nuclear power plant and a paper pulp mill. Models of the present study indicated that variation in trace element accumulation was linked to distance upstream from the estuary, dissolved oxygen, percentage of silt and clay in the sediment, elemental concentrations in sediment, shell length, and bivalve condition index. By explicitly modeling environmental variability, the Hierarchical linear modeling procedure allowed the identification of sites showing increased accumulation of trace elements that may have been caused by human activity. Hierarchical linear modeling is a useful tool for accounting for environmental and individual sources of variation in bioaccumulation studies. ?? 2009 SETAC.

Development of a Fish Stress Protein Antibody/Antigen-Based Approach for Biomonitoring of Water Quality.

DTIC Science & Technology

1993-01-25

10 DISCUSSION ............................................... 14 FIELD TESTS OF ANTIBODY DETECTION OF HEAT SHOCK PROTEIN ACCUMULATION IN... TESTS OF ANTIBODY DETECTION OF HEAT SHOCK PROTEIN ACCUMULATION IN ASIAN CLAMS (CORBICULA FLUMINEA) INTRODUCTION The Trinity River flows through...the utility of induction of heat shock proteins as an indicator of stress in another test organism, the Asian clam (Corbicula fluminea). This organism

Water-quality assessment of the Albemarle-Pamlico Drainage Basin, North Carolina and Virginia; organochlorine compounds in Asiatic clam (Corbicula fluminea) soft tissues and whole redbrest sunfish (Lepomis auritus) 1992-93

USGS Publications Warehouse

Smith, K.E.; Ruhl, P.M.

1996-01-01

The analysis of potential contaminants in biological tissues is an important part of many water-quality assessment programs, including the National Water-Quality Assessment (NAWQA) Program. Tissue analyses often are used to provide information about (1) direct threats to ecosystem integrity, and (2) the occurrence and distribution of potential contaminants in the environment. During 1992-93, Asiatic clam (Corbicula fluminea) soft tissues and whole redbreast sunfish (Lepomis auritus) samples were collected and analyzed to obtain information about the occurrence and distribution of organochlorine compounds in the Albemarle-Pamlico drainage Basin of North Carolina and Virginia. The investigation was conducted as part of the NAWQA Program. Relatively few organochlorine compounds were detected and of the compounds detected, all were detected in relatively low concentrations. The organochlorine compounds detected were p,p'-DDD, p,p'-DDE, p,p'-DDT, dieldrin, trans-nonachlor, PCB's, and toxaphene. Multiple compounds were detected at 16 of 19 sites sampled. Compared to Asiatic clams, redbreast sunfish appear to be better bioindicators of organochlorine contamination in aquatic systems. Except for one detection of toxaphene, pesticide concentrations are well below the National Academy of Sciences and National Academy of Engineering (NAS/NAE) guidelines for the protection of fish-eating wildlife.

Linking terrestrial and estuarine ecosystems: Organic matter sources supporting the high secondary production of a non-indigenous bivalve

EPA Science Inventory

The Asian clam Corbicula fluminea is one of the most pervasive species in freshwater ecosystems. Our objective was to characterize the trophic interactions of C. fluminea in the Minho river estuary (NW-Iberian Peninsula, Europe), an estuarine ecosystem in which C. fluminea presen...

Feeding inhibition in Corbicula fluminea (O.F. Muller, 1774) as an effect criterion to pollutant exposure: Perspectives for ecotoxicity screening and refinement of chemical control.

PubMed

Castro, Bruno Branco; Silva, Carlos; Macário, Inês Patrunilho Efe; Oliveira, Bruno; Gonçalves, Fernando; Pereira, Joana Luísa

2018-03-01

Bivalves are commonly used in biomonitoring programs to track pollutants. Several features, including its filter-feeding abilities, cumulatively argue in favour of the use of the Asian clam (Corbicula fluminea) as a biosentinel and an ecotoxicological model. Filtration in bivalves is very sensitive to external stimuli and its control is dictated by regulation of the opening/closure of the valves, which may be used as an avoidance defence against contaminants. Here, we investigate the filter-feeding behaviour of the Asian clam as an endpoint for assessing exposure to pollutants, driven by two complementary goals: (i) to generate relevant and sensitive toxicological information based on the ability of C. fluminea to clear an algal suspension, using the invasive species as a surrogate for native bivalves; (ii) to gain insight on the potential of exploring this integrative response in the refinement of chemical control methods for this pest. Clearance rates and proportion of algae removed were measured using a simple and reproducible protocol. Despite some variation across individuals and size classes, 50-90% of food particles were generally removed within 60-120 min by clams larger than 20 mm. Removal of algae was sensitive to an array of model contaminants with biocide potential, including fertilizers, pesticides, metals and salts: eight out of nine tested substances were detected at the μg l -1 or mg l -1 range and triggered valve closure, decreasing filter-feeding in a concentration-dependent manner. For most toxicants, a good agreement between mortality (96 h - LC 50 within the range 0.4-5500 mg l -1 ) and feeding (2 h - IC 50 within the range 0.005-2317 mg l -1 ) was observed, demonstrating that a 120-min assay can be used as a protective surrogate of acute toxicity. However, copper sulphate was very strongly avoided by the clams (IC 50  = 5.3 μg l -1 ); on the contrary, dichlorvos (an organophosphate insecticide) did not

Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water.

PubMed

Merschel, Gila; Bau, Michael

2015-11-15

High-technology metals - such as the rare earth elements (REE) - have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. Copyright © 2015 Elsevier B.V. All rights reserved.

The fat and protein fractions of freshwater clam ( Corbicula fluminea) extract reduce serum cholesterol and enhance bile acid biosynthesis and sterol excretion in hypercholesterolaemic rats fed a high-cholesterol diet.

PubMed

Chijimatsu, Takeshi; Umeki, Miki; Okuda, Yuji; Yamada, Koji; Oda, Hiroaki; Mochizuki, Satoshi

2011-02-01

We investigated whether the fat and protein fractions of freshwater clam (Corbicula fluminea) extract (FCE) could ameliorate hypercholesterolaemia in rats fed a high-cholesterol diet. We also explored the mechanism and the components that exert the hypocholesterolaemic effect of FCE. The doses of the fat and protein fractions were equivalent to those in 30 % FCE. The fat and protein fractions of FCE, two major components of FCE, significantly reduced the serum and hepatic cholesterol levels. The fat fraction more strongly reduced serum cholesterol levels than the same level of total FCE. The excretion of faecal neutral sterols increased in rats fed the total the FCE and the fat fraction of FCE. On the other hand, faecal bile acid levels were greater in rats fed the total FCE and the fat and protein fractions of FCE than in control animals. The hepatic gene expression of ATP-binding cassette transporter G5 and cholesterol 7α-hydroxylase was up-regulated by the administration of the total FCE and both the fat and protein fractions of FCE. These results showed that the fat and protein fractions of FCE had hypocholesterolaemic properties, and that these effects were greater with the fat fraction than with the protein fraction. The present study indicates that FCE exerts its hypocholesterolaemic effects through at least two different mechanisms, including enhanced excretion of neutral sterols and up-regulated biosynthesis of bile acids.

Water-quality assessment of the Albemarle-Pamlico drainage basin, North Carolina and Virginia; trace elements in Asiatic clam (Corbicula fluminea) soft tissues and redbreast sunfish (Lepomis auritus) livers, 1992-93

USGS Publications Warehouse

Ruhl, P.M.; Smith, K.E.

1996-01-01

The analysis of potential contaminants in biological tissues is an important part of many water-quality assessment programs, including the National Water-Quality Assessment (NAWQA) Program. Tissue analyses often are used to provide information about (1) direct threats to ecosystem integrity, and (2) the occurrence and distribution of potential contaminants in the environment. During 1992-93, trace elements in Asiatic clam (Corbicula fluminea) soft tissues and redbreast sunfish (Lepomis auritus) livers were analyzed to obtain information about the occurrence and distribution of trace element contaminants in the Albemarle-Pamlico Drainage Basin of North Carolina and Virginia. The investigation was conducted as part of the NAWQA Program. All but 3 of the 22 trace elements that were analyzed were detected. Although all 10 of the U.S. Environmental Protection Agency (U.S. EPA) priority pollutants were detected in the tissues sampled, they were present in relatively low concentrations. Concentrations of U.S. EPA priority pollutants in Asiatic clams collected in the Albemarle-Pamlico Drainage Basin are similar to concentrations observed in other NAWQA study units in the southeastern United States. Mercury (a U.S. EPA priority pollutant) was widely detected, being present in 29 of 30 tissue samples, but concentrations did not exceed the FDA action level for mercury of a risk-based screening value for the general public. Mercury concentrations in Asiatic clams were similar to concentrations in other NAWQA study areas in the Southeast.

Preliminary results from a shallow water benthic grazing study

USGS Publications Warehouse

Jones, N.L.; Monismith, Stephen G.; Thompson, Janet K.

2005-01-01

Despite great improvements in our knowledge on the effects of benthic grazers on seston concentrations in water columns, the effects of different hydrodynamic conditions on grazing rates has not been formulated. This makes it difficult to assess the system-wide effect of the benthic ecosystem on phytoplankton concentrations. Furthermore, it affects our ability to predict the potential success of a benthic species, such as the invasive clams Corbicula fluminea and Potamocorbula amurensis. This paper presents the preliminary results of a control volume approach to elucidate the effect of different hydrodynamic conditions on the grazing rates of Corbicula fluminea.

Biofiltration using C. fluminea for E.coli removal from water: Comparison with ozonation and photocatalytic oxidation.

PubMed

Gomes, João F; Lopes, Ana; Gonçalves, Daniel; Luxo, Cristina; Gmurek, Marta; Costa, Raquel; Quinta-Ferreira, Rosa M; Martins, Rui C; Matos, Ana

2018-06-06

Corbicula fluminea, an Asian clam, is one of the worst invasive species in Europe that can survive in very adverse environmental conditions. Despite its negative impacts, the species also has the capacity to bioaccumulate heavy metals, contaminants and can be exploited for wastewater treatment purposes. The capacity of the Asian clam to remove Escherichia coli, used as fecal contamination indicator, was analyzed. Conventional wastewater treatment plants are not suitable to remove bacteria, thus resulting in treated municipal wastewater with high bacterial loads. E. coli clearance rate was analyzed as function of the number of clams. The bivalves can remove bacteria until concentrations below the detection limit in about 6 h. The adsorption on the clam shells' and bioaccumulation on the soft tissues were also analyzed. The depuration of clams along 48 h were analyzed revealing that no bacteria was detected in the water. Thus, these results suggest that Asian clam can bioprocess E. coli. On the other hand, results obtained by this methodology were compared with ozonation and photocatalytic oxidation using TiO 2 , Ag, Au, Pd-TiO 2 . In all treatments it was possible to achieve concentrations of E. coli below the detection limit. However, photocatalytic oxidation demands about 4700 folds more energy than ozonation, besides the costs associated with catalysts. Comparing complexity of ozonation with biofiltration, this study suggests that application of biofiltration using C. fluminea can be a suitable solution to minimize the presence of bacteria in wastewater, reducing environmental and economic impacts. Copyright © 2018 Elsevier Ltd. All rights reserved.

Climate controls the distribution of a widespread invasive species: Implications for future range expansion

USGS Publications Warehouse

McDowell, W.G.; Benson, A.J.; Byers, J.E.

2014-01-01

1. Two dominant drivers of species distributions are climate and habitat, both of which are changing rapidly. Understanding the relative importance of variables that can control distributions is critical, especially for invasive species that may spread rapidly and have strong effects on ecosystems. 2. Here, we examine the relative importance of climate and habitat variables in controlling the distribution of the widespread invasive freshwater clam Corbicula fluminea, and we model its future distribution under a suite of climate scenarios using logistic regression and maximum entropy modelling (MaxEnt). 3. Logistic regression identified climate variables as more important than habitat variables in controlling Corbicula distribution. MaxEnt modelling predicted Corbicula's range expansion westward and northward to occupy half of the contiguous United States. By 2080, Corbicula's potential range will expand 25–32%, with more than half of the continental United States being climatically suitable. 4. Our combination of multiple approaches has revealed the importance of climate over habitat in controlling Corbicula's distribution and validates the climate-only MaxEnt model, which can readily examine the consequences of future climate projections. 5. Given the strong influence of climate variables on Corbicula's distribution, as well as Corbicula's ability to disperse quickly and over long distances, Corbicula is poised to expand into New England and the northern Midwest of the United States. Thus, the direct effects of climate change will probably be compounded by the addition of Corbicula and its own influences on ecosystem function.

Progressing Insensitive Munitions: Benefits and Techniques for Proactively Addressing Environmental Regulations

DTIC Science & Technology

2012-05-01

X Worm Tubifex tubifex X X X Black worm Lumbriculus X Asiatic clam Corbicula fluminea X Estuarine/marine water column Mysid shrimp Americamysis...Objective: Characterize traditional and insensitive munitions (IMs) impacts on amphibian larvae to manage a candidate for T&E status that inhabit

Active biomonitoring with Corbicula for USEPA priority pollutant and metal sources in the Anacostia River (DC, Maryland, USA).

PubMed

Phelps, Harriette L

2016-07-01

The freshwater Anacostia River watershed (Maryland, DC, USA) was surveyed for the sources of bioavailable US Environmental Protection Agency (USEPA) Priority Pollutants and toxic metals by active biomontoring (ABM) using the freshwater Asiatic clam Corbicula fluminea. The Anacostia River is a 456 km(2) tributary of the tidal freshwater Potomac River that includes the city of Washington, DC where edible fish are highly contaminated with PCBs and chlordane. From 1999 to 2011, Corbicula were collected for ABM from a Potomac reference site and translocated in cages placed at 45 sites in the tidal and nontidal Anacostia watershed. Minimum clam mortality and maximum contaminant bioaccumulation was with 2-week translocation. The clam tissues (28-50) were combined at sites and analyzed by TestAmerica for 66 USEPA Priority Pollutants plus technical chlordane, benz(e) pyrene, and 6 metals (As, Cd, Cr, Cu, Fe, Pb). Tissue contaminants reflected water, not sediment, levels. To compare sites, all contaminant data above detection or reference were grouped as total metals (TMET), total polycyclic aromatic hydrocarbons (TPAH), total PCB congeners (TPCB), total pesticides (TPEST), and total technical chlordane (TCHL). Tidal Anacostia ABM found highest TPAH and TCHL upstream at Bladensburg Marina (MD) except for TCHL at site PP near the confluence. Five nontidal MD subtributaries (94% of flow) had 17 sites with bioavailable TPAH, TPCB, or TCHL 2 to 3 times higher than found at the toxic-sediment "hotspots" near Washington. The only TMET noted was Fe at 1 site. TPAH in MD subtributaries was highest near industrial parks and Metro stations. A naphthalene spill was detected in Watts Branch. TPCB (low molecular weight) originated upstream at 1 industrial park. Total technical chlordane (80% of TPEST) was 2 to 5 times the US Food and Drug Administration action in 4 nontidal tributaries where heptachlor indicated legacy chlordane dumpsites. Total technical chlordane fell to reference

In vitro test systems supporting the development of improved pest control methods: a case study with chemical mixtures and bivalve biofoulers.

PubMed

Silva, Carlos; Nunes, Bruno; Nogueira, António Ja; Gonçalves, Fernando; Pereira, Joana L

2016-11-01

Using the bivalve macrofouler Corbicula fluminea, the suitability of in vitro testing as a stepping stone towards the improvement of control methods based on chemical mixtures was addressed in this study. In vitro cholinesterase (ChE) activity inhibition following single exposure of C. fluminea tissue to four model chemicals (the organophosphates dimethoate and dichlorvos, copper and sodium dodecyl phosphate [SDS]) was first assessed. Consequently, mixtures of dimethoate with copper and dichlorvos with SDS were tested and modelled; mixtures with ChE revealed synergistic interactions for both chemical pairs. These synergic combinations were subsequently validated in vivo and the increased control potential of these selected combinations was verified, with gains of up to 50% in C. fluminea mortality relative to corresponding single chemical treatments. Such consistency supports the suitability of using time- and cost-effective surrogate testing platforms to assist the development of biofouling control strategies incorporating mixtures.

Sensory determinants of valve rhythm dynamics provide in situ biodetection of copper in aquatic environments.

PubMed

Jou, Li-John; Chen, Bo-Ching; Chen, Wei-Yu; Liao, Chung-Min

2016-03-01

This study successfully applied an improved valvometry technique to measure waterborne copper (Cu), based on valve activity dynamics of the freshwater clam Corbicula fluminea. The improved valvometry technique allows the use of free-range bivalves and avoids causing stresses from experimental artifacts. The proposed daily valve rhythm models and a toxicodynamics-based Hill model were linked to predict valve dynamic responses under different Cu exposures with a circadian valve rhythm endpoint. Cu-specific detection threshold was 5.6 (95 % CI 2.1-9.3) and 19.5 (14.6-24.3) μg L(-1) for C. fluminea, based on response times of 300 and 30 min, respectively. Upon exposure to Cu concentrations in excess of 50 μg L(-1), the alteration of valve rhythm behavior was correlated with Cu concentration within 30 min, indicating notable sensing ability. This study outlines the feasibility of an in situ early warning dynamic biomonitoring system for detection of waterborne Cu based on circadian valve activities of C. fluminea.

From water to land: How an invasive clam may function as a resource pulse to terrestrial invertebrates.

PubMed

Novais, Adriana; Souza, Allan T; Ilarri, Martina; Pascoal, Cláudia; Sousa, Ronaldo

2015-12-15

Resource pulses are episodes of low frequency, large magnitude and short duration that result in increased resource availability in space and time, with consequences for food web dynamics. Studies assessing the importance of resource pulses by invasive alien species in the interface between terrestrial and aquatic ecosystems are rare, especially those in the direction from water to land. This study assessed the importance of massive die-offs of the Asian clam Corbicula fluminea (Müller, 1774) as a resource pulse to the terrestrial invertebrate community after an extreme climatic event using a manipulative experiment. We used 5 levels of C. fluminea density (0, 100, 500, 1000 and 2000ind·m(-2)), with terrestrial invertebrates being censused 7, 30 and 90days after C. fluminea addition. We also assessed the possible effect of plots position, where plots that delimited the experiment were assigned as edge plots and the remaining as core plots. Clear differences were detected in abundance, biomass, richness and diversity of terrestrial invertebrates depending on the C. fluminea density, time and position. Interestingly, the highest abundance of adult Diptera was observed 7days after C. fluminea addition, whereas that of the other terrestrial invertebrates was on day 30, both with C. fluminea densities higher than 500ind·m(-2) located on the edge of the experimental design. This study highlights the importance of major resource pulses after massive die-offs of invasive bivalves, contributing with remarkable amounts of carrion for adjacent terrestrial systems. Part of this carrion can be consumed directly by a great number of invertebrate species while the remainder can enter the detrital food web. Given the high density and biomass attained by several invasive bivalves worldwide and the predicted increase in the number, intensity and magnitude of extreme climatic events, the ecological importance of this phenomenon should be further investigated. Copyright © 2015

Structure and spatial patterns of macrobenthic community in Tai Lake, a large shallow lake, China

USGS Publications Warehouse

Di Li,; Erickson, Richard A.; Song Tang,; Xuwen Li,; Niu, Zhichun; Xia Wang,; Hongling Liu,; Hongxia Yu,

2016-01-01

Tai Lake (Chinese: Taihu), the third-largest freshwater lake in China, suffers from harmful cyanobacteria blooms that are caused by economic development and population growth near the lake. Several studies have focused on phytoplankton in Tai Lake after a drinking water crisis in 2007; however, these studies primarily focused on microcystin bioaccumulation and toxicity to individual species without examining the effects of microcystin on macrobenthic community diversity. In this study, we conducted a survey of the lake to examine the effects of microcystine and other pollutants on marcobenthic community diversity. A totally of forty-nine species of macroinvertebrates were found in Tai Lake. Limnodrilus hoffmeisteri and Corbicula fluminea were the most abundant species. Cluster-analysis and one-way analysis of similarity (ANOSIM) identified three significantly different macrobenthic communities among the sample sites. More specifically, sites in the eastern bays, where aquatic macrophytes were abundant, had the highest diversity of macrobenthic communities, which were dominated by Bellamya aeruginosa, Bellamya purificata, L. hoffmeisteri, and Alocinma longicornis. Sites in Zhushan Bay contained relatively diverse communities, mainly composed of L. hoffmeisteri, C. fluminea, L. claparederanus, R. sinicus, and Cythura sp. Sites in the western region, Meiliang Bay and Wuli Bay had the lowest diversity, mainly composed ofL. hoffmeisteri, C. fluminea, Branchiura sowerbyi, and Rhyacodrilus sinicus. In addition, the relationships between macrobenthic metrics (Shannon–Wiener, Margalef, and Pielou) and environmental variables showed that community structure and spatial patterns of macrobenthos in Tai Lake were significantly influenced by chemical oxygen demand (CODCr), biochemical oxygen demand (BOD5), lead (Pb), and microcystin-LR (L for leucine and R for arginine). Our findings provide critical information that could help managers and policymakers

Ecological consequences of invasion across the freshwater-marine transition in a warming world.

PubMed

Crespo, Daniel; Solan, Martin; Leston, Sara; Pardal, Miguel A; Dolbeth, Marina

2018-02-01

The freshwater-marine transition that characterizes an estuarine system can provide multiple entry options for invading species, yet the relative importance of this gradient in determining the functional contribution of invading species has received little attention. The ecological consequences of species invasion are routinely evaluated within a freshwater versus marine context, even though many invasive species can inhabit a wide range of salinities. We investigate the functional consequences of different sizes of Corbicula fluminea -an invasive species able to adapt to a wide range of temperatures and salinity-across the freshwater-marine transition in the presence versus absence of warming. Specifically, we characterize how C. fluminea affect fluid and particle transport, important processes in mediating nutrient cycling (NH 4 -N, NO 3 -N, PO 4 -P). Results showed that sediment particle reworking (bioturbation) tends to be influenced by size and to a lesser extent, temperature and salinity; nutrient concentrations are influenced by different interactions between all variables (salinity, temperature, and size class). Our findings demonstrate the highly context-dependent nature of the ecosystem consequences of invasion and highlight the potential for species to simultaneously occupy multiple components of an ecosystem. Recognizing of this aspect of invasibility is fundamental to management and conservation efforts, particularly as freshwater and marine systems tend to be compartmentalized rather than be treated as a contiguous unit. We conclude that more comprehensive appreciation of the distribution of invasive species across adjacent habitats and different seasons is urgently needed to allow the true extent of biological introductions, and their ecological consequences, to be fully realized.

Spatial and taxonomic variation in trace element bioaccumulation in two herbivores from a coal combustion waste contaminated stream.

PubMed

Fletcher, Dean E; Lindell, Angela H; Stillings, Garrett K; Mills, Gary L; Blas, Susan A; Vaun McArthur, J

2014-03-01

Dissimilarities in habitat use, feeding habits, life histories, and physiology can result in syntopic aquatic taxa of similar trophic position bioaccumulating trace elements in vastly different patterns. We compared bioaccumulation in a clam, Corbicula fluminea and mayfly nymph Maccaffertium modestum from a coal combustion waste contaminated stream. Collection sites differed in distance to contaminant sources, incision, floodplain activity, and sources of flood event water and organic matter. Contaminants variably accumulated in both sediment and biofilm. Bioaccumulation differed between species and sites with C. fluminea accumulating higher concentrations of Hg, Cs, Sr, Se, As, Be, and Cu, but M. modestum higher Pb and V. Stable isotope analyses suggested both spatial and taxonomic differences in resource use with greater variability and overlap between species in the more physically disturbed site. The complex but essential interactions between organismal biology, divergence in resource use, and bioaccumulation as related to stream habitat requires further studies essential to understand impacts of metal pollution on stream systems. Copyright © 2014 Elsevier Inc. All rights reserved.

Using biochemical and isotope geochemistry to understand the environmental and public health implications of lead pollution in the lower Guadiana River, Iberia: a freshwater bivalve study.

PubMed

Company, R; Serafim, A; Lopes, B; Cravo, A; Shepherd, T J; Pearson, G; Bebianno, M J

2008-11-01

Lead is a natural component of aquatic ecosystems with no known biological role and is highly toxic. Its toxicity stems from its ability to mimic biologically important metals and to produce membrane damage through lipid peroxidation (LPO). Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme, delta-aminolevulinic acid dehydratase (ALAD), the activity of which is markedly inhibited by lead. The purpose of this work was to study the levels and effects of lead pollution (responses of ALAD and oxidative stress biomarker LPO) in the freshwater bivalve Corbicula fluminea along the lower Guadiana River (Portugal and Spain); a major river system impacted by historic mining pollution and more recent anthropogenic inputs. The results show that the enzymatic activity of ALAD is negatively correlated with the total Pb concentration of the whole tissue suggesting that ALAD has considerable potential as a biomarker of lead exposure in C. fluminea. To identify the sources of lead to which bivalves have been exposed, high precision (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)/Pb ratios for C. fluminea confirm that historical mining activities in the Iberian Pyrite Belt are the dominant source of lead pollution in the lower Guadiana River. The isotope patterns however exhibit marked seasonal and geographic variation in response to rainfall and river water management. Locally, other anthropogenic sources of lead have been detected in C. fluminea close to population centres, thus adding to its versatility as a freshwater bio-indicator. Overall, the study highlights the value of natural ecosystems as monitors of water quality and their importance for public health assessment and surveillance.

Suspended material availability and filtration-biodeposition processes performed by a native and invasive bivalve species in streams

USGS Publications Warehouse

Atkinson, C.L.; First, M.R.; Covich, A.P.; Opsahl, S.P.; Golladay, S.W.

2011-01-01

Unionid mussels are among the most threatened group of freshwater organisms globally. They are known for their ability to filter food particles from flowing and standing waters. However, invasive bivalve species, such as the Asian clam (Corbicula fluminea) in North America, have the potential to overlap in feeding and potentially out-compete the native species. Yet, the feeding preferences of unionid mussels and C. fluminea are incompletely understood. We hypothesized that Elliptio crassidens (native) and C. fluminea (invasive) would select for specific organic components present within seston. We examined changes in seston (dry mass and ash-free dry mass) resulting from bivalve feeding activity for three size classes of material that were isolated using gravimetric filtration. The treatments were also sub-sampled for flow cytometry (FC) which separated the suspended materials in the stream water into five categories: detritus, heterotrophic bacteria, picoautotrophs, nanoautotrophs, and heterotrophic nanoeukaryotes. Our results indicated that both species of bivalve showed preferences for organic and living materials. E. crassidens preferentially filtered nanoeukaryotes, whose decreases were associated with an increase in bacteria. In contrast, C. fluminea preferred smaller materials through selective filtration of picoautotrophs. In addition, both species increased the concentration of large materials toward the end of the experiment because of the suspension of their pseudofeces biodeposits. To our knowledge, this study is the first to examine grazing by bivalve species on natural stream particulate matter using FC. Our results suggest that native and non-native mussels have different functional roles, which has important implications for organic matter processing and food webs in streams. ?? 2011 Springer Science+Business Media B.V.

Arsenic (V) bioconcentration kinetics in freshwater macroinvertebrates and periphyton is influenced by pH.

PubMed

Lopez, Adeline R; Funk, David H; Buchwalter, David B

2017-05-01

Arsenic is an important environmental pollutant whose speciation and mobility in freshwater food webs is complex. Few studies have characterized uptake and efflux rates of arsenic in aquatic benthic invertebrates. Further, we lack a fundamental understanding of how pH influences uptake kinetics in these organisms or how this key environmental variable could alter dietary exposure for primary consumers. Here we used a radiotracer approach to characterize arsenate accumulation dynamics in benthic invertebrates, the influence of pH on uptake in a subset of these organisms, and the influence of pH on uptake of arsenate by periphyton - an important food source at the base of aquatic food webs. Uptake rate constants (K u ) from aqueous exposure were modest, ranging from ∼0.001 L g -1 d -1 in three species of mayfly to 0.06 L g -1 d -1 in Psephenus herricki. Efflux rate constants ranged from ∼0.03 d -1 in Corbicula fluminea to ∼0.3 d -1 in the mayfly Isonychia sp, and were generally high. Arsenate uptake decreased with increasing pH, which may be a function of increased adsorption at lower pHs. A similar but much stronger correlation was observed for periphyton where K u decreased from ∼3.0 L g -1 d -1  at 6.5 pH to ∼0.7 L g -1 d -1  at 8.5 pH, suggesting that site specific pH could significantly alter arsenic exposure, particularly for primary consumers. Together, these findings shed light on the complexity of arsenic bioavailability and help explain observed differences reported in the literature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Estimation of potential and limits of bivalve closure response to detect contaminants: application to cadmium.

PubMed

Tran, Damien; Ciret, Pierre; Ciutat, Aurélie; Durrieu, Gilles; Massabuau, Jean-Charles

2003-04-01

Bivalve closure responses to detect contaminants have often been studied in ecotoxicology as an aquatic pollution biosensor. We present a new laboratory procedure to estimate its potential and limits for various contaminants and animal susceptible to stress. The study was performed in the Asiatic clam Corbicula fluminea and applied to cadmium. To take into account the rate of spontaneous closures, we integrated stress problems associated with fixation by a valve in common apparatus and the spontaneous rhythm associated with circadian activity to focus on conditions with the lowest probability of spontaneous closing. Moreover, we developed an original system by impedance valvometry, using light-weight impedance electrodes, to study free-ranging animals in low-stress conditions and a new analytical approach to describe valve closure behavior as a function of response time and concentration of contaminant. In C. fluminea, we show that cadmium concentrations above 50 microg/L can be detected within less than 1 h, concentrations down to 16 microg/L require 5 h of integration time, and values lower than 16 microg/L cannot be distinguished from background noise. Our procedure improved by a factor of six the cadmium sensitivity threshold reported in the literature. Problems of field applications are discussed.

Light and scanning electron microscopic studies of Unionicola tetrafurcatus (Acari: Unionicolidae) infecting four freshwater bivalve species with referring to histopathological effect on its hosts.

PubMed

Abdel-Gaber, Rewaida; Fol, Mona; Al Quraishy, Saleh

2018-05-08

Water mites of the genus Unionicola are the most common symbionts of freshwater bivalves. During the current investigation, a total of 120 live freshwater mussels [Corbicula fluminea (Veneroida), Coelatura aegyptiaca (Unionoidea) Mutela rostrata and Chambardia rubens (Mutelidae)], were collected from 2 localities in Tura (Helwan Governorate) and El Kanater (Qaluobiya Governorate), Egypt. Only 3 of the 4 bivalve species listed are considered freshwater bivalves (members of Unionoidea). While, C. fluminea belong to the family Cyrenidae within Veneroida. The collected mussels were dissected and examined for the presence of unionicolid mites. It was found that 30.83% (37/120) were infected with a single mite species Unionicola tetrafurcatus (Unionicolidae). The highest prevalence was observed during the summer with 83.33% (25/30), whereas the least was observed in autumn, i.e. 33.33% (10/30). Mites were recovered from the gills, gonads, and visceral mass of mussel hosts. gills of host mussels were the primary site of oviposition for unionicola mites. Smaller bivalves in size had significantly greater numbers of mites than larger ones in size. Numbers of mites per host species was variable and the highest prevalence level of 83.33% (25/30) was recorded in C. fluminea, while, the lowest one of 16.66% (5/30) was found in C. rubens. Morphological and morphometric characterizations of mites revealed some differences between the present species and other related Unionicola. Histopathological responses of host mussels to the eggs, larvae, and cuticular remnants of U. tetrafurcatus were also studied. Therefore, the present study demonstrated that freshwater bivalves have a new host and locality records for infection with U. tetrafurcatus. Future studies are recommended to include advanced molecular characteristics for these mites.

Filter-feeding bivalves store and biodeposit colloidally stable gold nanoparticles.

PubMed

Hull, Matthew S; Chaurand, Perrine; Rose, Jerome; Auffan, Melanie; Bottero, Jean-Yves; Jones, Jason C; Schultz, Irvin R; Vikesland, Peter J

2011-08-01

Nanoparticles resistant to salt-induced aggregation are continually being developed for biomedical and industrial applications. Because of their colloidal stability these functionalized nanoparticles are anticipated to be persistent aquatic contaminants. Here, we show that Corbicula fluminea, a globally distributed clam that is a known sentinel of aquatic ecosystem contamination, can uptake and biodeposit bovine serum albumin (BSA) stabilized gold nanoparticles. Nanoparticle clearance rates from suspension were dictated by diameter and concentration, with the largest particles cleared most quickly on a mass basis. Particle capture facilitates size-selective 'biopurification' of particle suspensions with nanoscale resolution. Nanoparticles were retained either within the clam digestive tract or excreted in feces. Our results suggest that biotransformation and biodeposition will play a significant role in the fate and transport of persistent nanoparticles in aquatic systems.

Asiatic clam (Corbicula manilensis) and other foods used by waterfowl in the James River, Virginia

USGS Publications Warehouse

Perry, M.C.; Uhler, F.M.

1981-01-01

Corbicula manilensis was found in the gizzards of 24 ducks of 5 species taken from the James River, Virginia, between 1973 and 1976. Percent average volume in these species ranged from trace to 6%. This is the first known occurrence of this exotic clam in the food of duck in Chesapeake Bay. A total of 135 other food items was identified from the 116 gizzards of 9 species that were examined. Food that predominated included Cyperus spp., Leersia oryzoides, Polygonum spp., and Zea mays. The great diversity of food consumed in this fresh tidal section of the James River indicates the high value of these wetlands to waterfowl.

Assessing arsenic bioavailability through the use of bioassays

NASA Astrophysics Data System (ADS)

Diesel, E.; Nadimpalli, M.; Hull, M.; Schreiber, M. E.; Vikesland, P.

2009-12-01

Various methods have been used to characterize the bioavailability of a contaminant, including chemical extractions from soils, toxicity tests, bioaccumulation measurements, estimation from soil properties, in vitro/in vivo tests, and microbial biossays. Unfortunately, these tests are all unique (i.e. they measure bioavailability through different mechanisms) and it is difficult to compare measurements collected using one method to those collected from another. Additionally, there are fundamental aspects of bioavailability research that require further study. In particular, changes in bioavailability over time are not well understood, as well as what the geochemical controls are on changes in bioavailability. In addition, there are no studies aimed at the integration of bioavailability measurements and potential geochemical controls. This research project seeks to find a standard set of assays and sensors that can be used to assess arsenic bioavailability at any field site, as well as to use these tools and techniques to better understand changes in, and controls on, arsenic bioavailability. The bioassays to be utilized in this research are a bioluminescent E. coli assay and a Corbicula fluminea (Asian clam) assay. Preliminary experiments to determine the suitability of the E. coli and C. fluminea assays have been completed. The E. coli assay can be utilized to analyze As(III) and As(V) with a linear standard curve between 5 and 200 ppb for As(III) and 100 ppb and 5 ppm for As(V); no bioluminescent response above background was elicited in the presence of Roxarsone, an organoarsenical. The C. fluminea assay is capable of bioaccumulating As(III), As(V), Roxarsone, and MSMA, with As(III) being the most readily accumulated, followed by As(V), Roxarsone and MSMA, respectively. Additional research will include assessing bioavailability of various arsenic species adsorbed to natural colloidal materials (i.e. clays, iron oxides, NOM) to the E. coli and C. fluminea assays

Accumulation of trace elements, pesticides, and polychlorinated biphenyls in sediments and the clam Corbicula manilensis of the Apalachicola River, Florida

USGS Publications Warehouse

Elder, J.F.; Mattraw, H.C.

1984-01-01

A survey of trace element and synthetic organic compound concentrations in botton materials was conducted on the Apalachichola River in northwest Florida in 1979-80 as part of the Apalachicola River Quality Assessment. Substances analyzed included trace elements (predominantly heavy metals), organochlorine insecticides, organophosphorus insecticides, chlorinated phenoxy-acid herbicides, and polychlorinated biphenyls (PCBs). Three kinds of materials were surveyed: fine-grained sediments, whole-body tissue of the Asiatic clam Corbicula manilensis, and bottom-load organic detritus. No hazardous levels of any of the substances were found. Concentrations in the fine-grained sediments and clams were generally at least ten times lower than maximum limits considered safe for biota of aquatic systems. A comparison of trace-substance data from the Apalachicola River with data from Lake Seminole (upstream) and Apalachicola Bay (downstream) showed lower concentrations in riverine clams. Sediment concentrations in all parts of the system were comparable. Most trace substances in the Apalachicola River enter the river from the upstream part of the basin (the Chattahoochee and Flint Rivers in Georgia and Alabama) and from nonpoint sources throughout the basin. There are no major point discharges along the Apalachicola. Trend analysis was limited by the scope of the study, but did not reveal any spatial or temporal trends in concentrations of any of the substances analyzed. Concentrations of organic compounds and most metals in Corbicula manilensis did not correlate with those in sediments.

An Early Instance of Upper Palaeolithic Personal Ornamentation from China: The Freshwater Shell Bead from Shuidonggou 2.

PubMed

Wei, Yi; d'Errico, Francesco; Vanhaeren, Marian; Li, Feng; Gao, Xing

2016-01-01

We report the discovery and present a detailed analysis of a freshwater bivalve from Shuidonggou Locality 2, layer CL3. This layer is located c. 40 cm below layer CL2, which has yielded numerous ostrich eggshell beads. The shell is identified as the valve of a Corbicula fluminea. Data on the occurrence of this species in the Shuidonggou region during Marine Isotope Stage 3 and taphonomic analysis, conducted in the framework of this study, of a modern biocoenosis and thanatocoenosis suggest that the archeological specimen was collected at one of the numerous fossil or sub-fossil outcrops where valves of this species were available at the time of occupation of level CL3. Experimental grinding and microscopic analysis of modern shells of the same species indicate that the Shuidonggou shell was most probably ground on coarse sandstone to open a hole on its umbo, attach a thread, and use the valve as a personal ornament. Experimental engraving of freshwater shells and microscopic analysis identify an incision crossing the archaeological valve outer surface as possible deliberate engraving. Reappraisal of the site chronology in the light of available radiocarbon evidence suggests an age of at least 34-33 cal kyr BP for layer CL3. Such estimate makes the C. fluminea recovered from CL3 one of the earliest instances of personal ornamentation and the earliest example of a shell bead from China.

Peat Water Purification by Hydroxyapatite (HAp) Synthesized from Waste Pensi (Corbicula moltkiana) Shells

NASA Astrophysics Data System (ADS)

Fajri Alif, Matlal; Aprillia, Wandha; Arief, Syukri

2018-01-01

Hydroxyapatite (HAP) were synthesized from Pensi (Corbicula moltkiana) sheels by hydrothermal method and used as adsorbent for peat water purification. Batch adsorption experiments were performed to investigate the effects of various factors such as contact time, adsorbent dosage, and pH. The obtained materials were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). Results showed that HAP calcined at 900°C (HAP900) and 1000°C (HAP1000) have a poorly crystalline shape. HAP900 also contain Tetracalsium Phosphate (TTCP) with a Ca/P molar ratio 2.18, while HAP 1000 contain HAp with a Ca/P molar ratio 1.67. Optimum condition for peat water purification with HAP900 and HAP1000 were both achieved at 1 hours, 1 grams adsorben mass at pH 2. SEM micrographs show that after purification, the surface of HAP were covered by organic compounds from peat water.

A malacological survey in the Manso Power Plant, State of Mato Grosso, Brazil: new records of freshwater snails, including transmitters of schistosomiasis and exotic species.

PubMed

Fernandez, Monica Ammon; Mattos, Aline Carvalho de; Silva, Elizangela Feitosa da; Santos, Sonia Barbosa Dos; Thiengo, Silvana Carvalho

2014-07-01

Schistosomiasis is a parasitic disease of public health concern in Brazil, and the construction of hydroelectric dams, in addition to increasing permanent human settlement and tourism, has created conditions suitable for the establishment of mollusks that can transmit schistosomiasis. Such areas require a number of actions to prevent the establishment of schistosomiasis. This paper reports on a freshwater malacological survey carried out in the geographical area of the Manso Power Plant. Mollusks were collected in 18 municipalities in the State of Mato Grosso between February 2002 and February 2004 (qualitative study) and from April 2009 to February 2011 (quantitative study). Thirty-one species of mollusks were collected, including newly recorded species (Antillorbis nordestensis and Burnupia ingae). In addition, the geographic distributions of known species, including Biomphalaria straminea, a snail vector of Schistosoma mansoni, were expanded. A total of 4,507 specimens were collected in the APM Manso reservoir (Usina Hidrelétrica de Aproveitamento Múltiplo de Manso) during the quantitative study, and Biomphalaria amazonica was found in six of the 10 localities analyzed. The Afroasiatic species Melanoides tuberculata, introduced after February 2009, was the dominant species (relative abundance 94.96%). The study area is epidemiologically important due to the occurrence of B. straminea and B. amazonica, which are vectors of schistosomiasis, and M. tuberculata, a snail host of Centrocestus formosanus, which is responsible for centrocestiasis transmission. Observations of M. tuberculata and the exotic freshwater clams Corbicula fluminea and Corbicula largillierti raise concerns about biodiversity.

Occurrence and accumulation of pesticides and organic contaminants in river sediment, water and clam tissues from the San Joaquin River and tributaries, California

USGS Publications Warehouse

Pereira, W.E.; Domagalski, Joseph L.; Hostettler, F.D.; Brown, L.R.; Rapp, J.B.

1996-01-01

A study was conducted in 1992 to assess the effects of anthropogenic activities and land use on the water quality of the San Joaquin River and its major tributaries. This study focused on pesticides and organic contaminants, looking at distributions of contaminants in water, bed and suspended sediment, and the bivalve Corbicula fluminea. Results indicated that this river system is affected by agricultural practices and urban runoff. Sediments from Dry Creek contained elevated concentrations of polycyclic aromatic hydrocarbons (PAHs), possibly derived from urban runoff from the city of Modesto; suspended sediments contained elevated amounts of chlordane. Trace levels of triazine herbicides atrazine and simazine were present in water at most sites. Sediments, water, and bivalves from Orestimba Creek, a westside tributary draining agricultural areas, contained the greatest levels of DDT (1,1,1-trichloro-2-2-bis[p-chlorophenyl]ethane), and its degradates DDD (1,1-dichloro-2,2-bis[p-chlorophenyl]ethane), and DDE (1,1-dichloro-2,2- bis[p-chlorophenyl]ethylene). Sediment adsorption co efficients (K(oc)), and bioconcentration factors (BCF) in Corbicula of DDT, DDD, and DDE at Orestimba Creek were greater than predicted values. Streams of the western San Joaquin Valley can potentially transport significant amounts of chlorinated pesticides to the San Joaquin River, the delta, and San Francisco Bay. Organochlorine compounds accumulate in bivalves and sediment and may pose a problem to other biotic species in this watershed.

Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

2008-01-31

The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used inmore » collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.« less

Protocol for monitoring metals in Ozark National Scenic Riverways, Missouri: Version 1.0

USGS Publications Warehouse

Schmitt, Christopher J.; Brumbaugh, William G.; Besser, John M.; Hinck, Jo Ellen; Bowles, David E.; Morrison, Lloyd W.; Williams, Michael H.

2008-01-01

The National Park Service is developing a monitoring plan for the Ozark National Scenic Riverways in southeastern Missouri. Because of concerns about the release of lead, zinc, and other metals from lead-zinc mining to streams, the monitoring plan will include mining-related metals. After considering a variety of alternatives, the plan will consist of measuring the concentrations of cadmium, cobalt, lead, nickel, and zinc in composite samples of crayfish (Orconectes luteus or alternate species) and Asian clam (Corbicula fluminea) collected periodically from selected sites. This document, which comprises a protocol narrative and supporting standard operating procedures, describes the methods to be employed prior to, during, and after collection of the organisms, along with procedures for their chemical analysis and quality assurance; statistical analysis, interpretation, and reporting of the data; and for modifying the protocol narrative and supporting standard operating procedures. A list of supplies and equipment, data forms, and sample labels are also included. An example based on data from a pilot study is presented.

Effects of millimeter wave carbon fibers on filter-feeding freshwater invertebrates.

PubMed

Soucek, David J; Dickinson, Amy; Cropek, Donald M

2010-05-01

The purpose of our study was to investigate the sub-lethal effects of millimeter wave carbon fibers (MWCF), a military obscurant, on filter-feeding freshwater invertebrates. We observed decreased survival, reproduction, and oxygen consumption in Daphnia magna at realistic loading rates. In experiments with the Asiatic clam (Corbicula fluminea), soft tissue dry weight and tissue condition index were not significantly different among control and MWCF exposed treatments; however, using a (15)N labeled alga as food, we observed decreased nitrogen turnover in tissues of clams exposed to MWCF, suggesting lower filtering or ingestion rates. Our findings combined with previous demonstrations of MWCF toxicity to green algae suggest that over a period of several months, bivalve growth may be inhibited, and cladoceran populations may be even more strongly affected by MWCF. Given that these fibers are persistent, further experiments should be conducted to determine the longer-term effects of contamination of water bodies with MWCF. Copyright 2009 Elsevier Inc. All rights reserved.

Integrative assessment of sediment quality in lower basin affected by former mining in Brazil.

PubMed

Bonnail, Estefanía; Buruaem, Lucas M; Morais, Lucas G; Araujo, Giuliana S; Abessa, Denis M S; Sarmiento, Aguasanta M; Ángel DelValls, T

2017-06-13

The Ribeira de Iguape River (Southeast Brazil) is metal contaminated by mining activities. Despite it has been cataloged as "in via of restoration" by the literature, this basin is still a sink of pollution in some segments of the fluvial system. This study aimed to assess the sediment quality in the lower part of the RIR basin. The employed approach was based on biological responses of the freshwater clam Corbicula fluminea after 7-day exposure bioassays using as the reference site the Perequê Ecological Park. Toxic responses (burial activity and lethality) and biochemical biomarkers (GST, GR, GPx, LPO, MTs, AChE and DNA damage) were evaluated and then integrated with metal bioavailability and chemical concentrations to address the sediment quality in the area through the weight-of-evidence approach. A multivariate analysis identified linkages between biological responses and contamination. Results pointed that, despite being below the benchmarks of the US Environmental Protection Agency, there is slight metal contamination in the lower part of the basin which induces oxidative stress in C. fluminea; other toxic responses were sometimes attributed to As and Cr bioaccumulation. The sediment quality values (TEL-PEL values in mg/kg) were calculated for the current study for As (0.63-1.31), Cr (3.5-11.05), Cs (1.0-1.17), Cu (6.32-7.32), Ni (6.78-7.46), Ti (42.0-215), V (1.77-8.00). By comparison with other international guidelines, the sediment quality of the lower basin of the Vale de Ribeira does not identify a significant environmental risk.

Assimilation of terrigenous organic matter via bacterial biomass as a food source for a brackish clam, Corbicula japonica (Mollusca: Bivalva)

NASA Astrophysics Data System (ADS)

Yamanaka, Toshiro; Mizota, Chitoshi; Maki, Yonosuke; Matsumasa, Masatoshi

2013-07-01

Corbicula japonica collected from the Kitakami River estuary, northeastern Japan, showed lower δ34S values in soft-body parts (+1.7 to +11.0‰) than the ambient seawater sulfate sulfur (+21‰), and this value gradually decreased at successive sites up to 15.8 km upstream from the river mouth. Previous study using carbon and nitrogen isotopes suggests that the bivalve nonselectively assimilates particulate organic matter of marine and terrestrial origin by filter feeding. This pattern in δ34S values may indicate a considerable contribution of a food source derived from terrigenous organic matter, which has low δ34S values close to 0‰, and the bivalve has been reported to have cellulase and hemicellulase activities. Unique fatty acids (iso 17:0 and anteiso 17:0 acids), both characteristic of sulfate-reducing bacteria, were observed in the salt-free, soft-body parts of the bivalve. The concentration of monounsaturated fatty acids, possibly derived from bacteria, was also high. Trace amounts of a polyunsaturated fatty acid (20:5ω3) specific to dinoflagellates were detected. In Corbicula habitats, reductive sandy layers with ample sulfides that were sporadically intercalated into the oxidative sandy sediment were often observed. The stable isotopic signatures of sediment sulfides (acid-volatile sulfide) and associated pore-water sulfates were -8.9 to +8.6‰ and +22.4 to +26.3‰, respectively, indicating the existence of bacterial sulfate-reducing activity and thiobios biomass. These isotopic signatures of the sediment, with the fatty acid composition of the bivalve, confirm the importance of a food source derived from bacteria belonging to the thiobios in the substrate sediments via pedal feeding, rather than direct digestion of terrigenous organic matter, in this estuarine ecosystem.

Corbicula fluminea as a Bioaccumulation Indicator Species: A Case Study at the Columbia and Willamette Rivers

DTIC Science & Technology

2009-06-01

metals including mercury (Hg), lead (Pb), zinc (Zn), and cadmium (Cd). The analytical methods used by the laboratories and sample identifications...moderate levels of mercury (46.5 ng/g), and undetectable levels of cadmium (< 0.1 μg/g). Within the large group, the first subgroup was a singleton...www.issg.org/database/. Inza, B., F. Ribeyre, and A. Boudou. 1998. Dynamics of cadmium and mercury compounds (inorganic mercury or methylmercury): Uptake

BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, CORBICULA FLUMINEA, LEPOMIS MACROCHIRUS, AND VIBRO FISCHERI

EPA Science Inventory

The research presented here is a continuation of work designed to further the science of available and developing continuous, automated water quality monitors and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system (W...

Cd, Cu, Pb and Zn in clams and sediments from an impacted estuary by the oil industry in the southwestern Gulf of Mexico: concentrations and bioaccumulation factors.

PubMed

Ruelas-Inzunza, J; Spanopoulos-Zarco, P; Páez-Osuna, F

2009-12-01

With the objective of estimating the temporal variation and bioavailability of Cd, Cu, Pb and Zn in Coatzacoalcos estuary, the biota-sediment accumulation factors (BSAF) were calculated. For this purpose, surficial sediments and clams from 14 selected sites were collected during three climatic seasons. In surficial sediments, highest levels of Cd and Cu were measured during the rainy season near to the industrial area of Minatitlan, while highest concentrations of Pb and Zn were registered during the windy season in sediments collected near to the industrial area of Coatzacoalcos. Considering all the sampling seasons and bivalve species, average metal concentrations followed the order Zn > Cu > Cd > Pb. BSAF ranged from 0.01 (Pb) in Corbicula fluminea during the hot season to 25.1 (Cd) in Polymesoda caroliniana during the windy season. BSAF of Cd, Cu and Zn were higher during the windy season; in the case of Pb, the dry season was the time when such figure was more elevated. It can be stated that Polymesoda caroliniana is a net accumulator of Cd and Zn and a weak accumulator of Pb for the studied estuary.

BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, CORBICULA FLUMINEA, AND LEPOMIS MACROCHIRUS TO COPPER AND CYANIDE

EPA Science Inventory

The research presented here was designed to further the science of available and developing continuous, automated water quality monitors and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system (WQEWS). Source waters ...

Bioaccumulation and trophic dilution of human pharmaceuticals across trophic positions of an effluent-dependent wadeable stream

PubMed Central

Du, Bowen; Haddad, Samuel P.; Luek, Andreas; Scott, W. Casan; Saari, Gavin N.; Kristofco, Lauren A.; Connors, Kristin A.; Rash, Christopher; Rasmussen, Joseph B.; Chambliss, C. Kevin; Brooks, Bryan W.

2014-01-01

Though pharmaceuticals are increasingly observed in a variety of organisms from coastal and inland aquatic systems, trophic transfer of pharmaceuticals in aquatic food webs have not been reported. In this study, bioaccumulation of select pharmaceuticals was investigated in a lower order effluent-dependent stream in central Texas, USA, using isotope dilution liquid chromatography–tandem mass spectrometry (MS). A fish plasma model, initially developed from laboratory studies, was tested to examine observed versus predicted internal dose of select pharmaceuticals. Pharmaceuticals accumulated to higher concentrations in invertebrates relative to fish; elevated concentrations of the antidepressant sertraline and its primary metabolite desmethylsertraline were observed in the Asian clam, Corbicula fluminea, and two unionid mussel species. Trophic positions were determined from stable isotopes (δ15N and δ13C) collected by isotope ratio-MS; a Bayesian mixing model was then used to estimate diet contributions towards top fish predators. Because diphenhydramine and carbamazepine were the only target compounds detected in all species examined, trophic magnification factors (TMFs) were derived to evaluate potential trophic transfer of both compounds. TMFs for diphenhydramine (0.38) and carbamazepine (1.17) indicated neither compound experienced trophic magnification, which suggests that inhalational and not dietary exposure represented the primary route of uptake by fish in this effluent-dependent stream. PMID:25313153

Interspecific Relationships in Benthic Assemblages of a Large Lowland River : Co-existence or Competition as a Result of Habitat Characteristics

NASA Astrophysics Data System (ADS)

Akopian, M.; Usseglio-Polatera, P.

2005-05-01

Macrobenthic assemblages of the lower, regulated and canalized Marne River (France) are dominated by several "exotic", recently introduced species. Arrival, installation and spread of such alien species were certainly promoted by (1) the close connection between French and other European river systems (Rhine, Danube), (2) the modification of natural river flow and benthic habitats. Both habitat characteristics (e.g. granulometric composition, organic content) and corresponding benthic assemblage structure were analysed to identify the substrate affinity of major taxa in the lower Marne River. The main aim of the study was to evaluate the possible biotic interactions (i.e. competition for food and/or space) among dominant taxa as function of habitat features and to predict the future development of newly established species, already known as potential invaders: Corbicula fluminea (Bivalvia), Hypania invalida (Polychaeta), Chelicorophium curvispinum (Amphipoda), etc. Most of the newly established species, coming from the same biogeographical area ("invasional meltdown" hypothesis?), are eurytopic, with high fecundity and large food spectrum. First results demonstrated the co-existence of such species in the Marne River. But the future ecological importance of these organisms in benthic assemblages of the river depends on their present population size, population dynamics, and ability to colonize bottom substrates.

Macrofouling control in nuclear power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ekis, E.W. Jr.; Keoplin-Gall, S.M.; McCarthy, R.E.

1991-11-01

Macrofouling of cooling-water systems is one of the more significant and costly problems encountered in the nuclear power industry. Both marine and freshwater macroinvertebrates can be responsible for losses in plant availability because of plugged intakes and heat transfer equipment. There is a greater diversity of macrofouling organisms in marine waters than in fresh waters. Marine macrofouling organisms include barnacles, mollusks, bryozoans, and hydroids. Barnacles are crustaceans with feathery appendages, which allow them to attach to a variety of surfaces. They are a major cause of severe macrofouling because they can remain attached even after death. The major freshwater macrofoulingmore » organisms include the Asiatic Clam (Corbicula fluminea) and the newest freshwater macrofouler, the Zebra Mussel (Dreissena polymorpha). The introduction of the Zebra Mussel into the Great Lakes has created economic and ecological problems that will not easily be solved. The threat of intercontinental dispersal of the Zebra Mussel in America is serious. Research programs have been initiated around the country to develop control methods for this macrofouling problem. The various control methodologies can be classified in the following categories: biological, chemical, physical, and mechanical. Laboratory experiments were performed to evaluate the efficacy of Actibrom against mature Zebra Mussels.« less

Toxicity of a traditional molluscicide to asian clam veligers

USGS Publications Warehouse

Layhee, Megan J.; ,; Miho Yoshioka,; Bahram Farokhkish,; ,; Gross, Jackson A.; Sepulveda, Adam J.

2014-01-01

Aquaculture and hatchery industries are in need of effective control methods to reduce the risk of spreading aquatic invasive species, such as the Asian clam Corbicula fluminea, through aquaculture and hatchery activities. The planktonic nature of Asian clam veligers enables this life stage to enter water-based infrastructure undetected, including hatchery trucks used to stock fish. Once in hatchery trucks, veligers can disperse overland and establish in previously uninvaded habitats. As a result, there is a need to develop techniques that result in veliger mortality but do not harm fish. In September 2012, we conducted laboratory trials to determine if a molluscicide (750 mg/L potassium chloride and 25 mg/L formalin) commonly used to kill zebra mussel (Dreissena polymorpha) veligers in hatchery trucks can also effectively kill Asian clam veligers. We exposed Asian clam veligers to this molluscicide for 1, 3, and 5 h in each of two water types: deionized water and filtered lake water. We found ,20% mortality at the 1-h exposure period and 100% mortality at both the 3-h and 5-h exposure periods, regardless of water type. This laboratory study represents an important step toward reducing the spread of Asian clams by aquaculture facilities.

Range expansion of an exotic Siberian prawn to the Lower Snake River

USGS Publications Warehouse

Haskell, Craig A.; Baxter, Rex D.; Tiffan, Kenneth F.

2006-01-01

The introduction of non-native plant and animal species in aquatic systems is of increasing concern because of their potentially negative ecological and economic impacts (Sytsma et al. 2004). There are many examples of food web repercussions resulting from non-native invertebrate introductions. For example, in Flathead Lake, Montana, the kokanee salmon (Oncorhynchus nerka) population crashed after the introduction of a planktivorous mysid, My-sis relicta caused restructuring of the zooplankton community (Spencer et al. 1991) and the introduc-tion of the spiny water flea (Bythotrephes spp.) to the Great Lakes also restructured zooplankton communities (Barbiero and Tuchman 2004). The zebra mussel (Dreissena polymorpha) has nearly extirpated some native unionid clams through competition for food and shell fouling (Strayer 1999). In San Francisco Bay, California, one of the most highly invaded estuaries in the world (Cohen and Carlton 1998), the benthic fauna has been highly modified by the introduction of hundreds of exotic invertebrates including the Chinese mitten crab (Eriocheir sinensis) and the Asian clam, Potamocorbula amurensis. Non-native invertebrate species, including the New Zealand mud snail (Potamopyrgus antipodarum) and an-other Asian clam, Corbicula fluminea, have also been introduced to the Columbia River (Sytsma et al. 2004), but the ecological effects to Columbia River species are largely unknown.

Occurrence and Distribution of Organochlorine Compounds in Biological Tissue and Bed Sediment From Streams in the Trinity River Basin, Texas, 1992-93

USGS Publications Warehouse

Moring, J. Bruce

1997-01-01

This report describes the occurrence and distribution of organochlorine compounds in biological tissue and bed sediment from the Trinity River Basin study area of the National Water-Quality Assessment Program. Concentrations of organochlorine pesticides, polychlorinated biphenyls (PCBs), and other organochlorine compounds were determined in biological tissue and surficial bed sediment from 16 stream sites in the Trinity River Basin of east-central Texas. Asiatic clams (Corbicula fluminea) were collected at 10 sites, and fish, including blue catfish (Ictalurus furcatus), common carp (Cyprinus carpio), bluegill (Lepomis cyanellus), and yellow bullhead (Ameiurus natalis) were collected at all mainstem and two tributary sites. Thirty of the 36 compounds analyzed in biological tissue or surficial bed sediment were detected in one or both media. Overall, more organochlorine compounds were detected in bed sediment than in biological tissue; however, various chlordane isomers, DDT metabolites, and PCBs were detected more frequently in tissue than in sediment. The chlordane isomers and PCBs that were detected more frequently in biological tissue also were detected more frequently at urban sites than at agricultural sites. Organochlorine compound concentrations generally were highest in fish tissue from Trinity River mainstem sites. Fish tissue from the mainstem sites contained a higher percentage of lipids than did fish- and clam-tissue samples from the tributary sites.

Zooplankton variability and larval striped bass foraging: Evaluating potential match/mismatch regulation

USGS Publications Warehouse

Chick, J.H.; Van Den Avyle, M.J.

1999-01-01

We quantified temporal and spatial variability of zooplankton in three potential nursery sites (river, transition zone, lake) for larval striped bass (Morone saxatilis) in Lake Marion, South Carolina, during April and May 1993-1995. In two of three years, microzooplankton (rotifers and copepod nauplii) density was significantly greater in the lake site than in the river or transition zone. Macrozooplankton (>200 ??m) composition varied among the three sites in all years with adult copepods and cladocerans dominant at the lake, and juvenile Corbicula fluminea dominant at the river and transition zone. Laboratory feeding experiments, simulating both among-site (site treatments) and within-site (density treatments) variability, were conducted in 1995 to quantify the effects of the observed zooplankton variability on foraging success of larval striped bass. A greater proportion of larvae fed in the lake than in the river or transition-zone treatments across all density treatments: mean (x), 10x and 100x. Larvae also ingested significantly more dry mass of prey in the lake treatment in both the mean and 10x density treatments. Field zooplankton and laboratory feeding data suggest that both spatial and temporal variability of zooplankton influence larval striped bass foraging. Prey density levels that supported successful foraging in our feeding experiments occurred in the lake during late April and May in 1994 and 1995 but were never observed in the river or transition zone. Because the rivers flowing into Lake Marion are regulated, it may be possible to devise flow management schemes that facilitate larval transport to the lake and thereby increase the proportion of larvae matched to suitable prey resources.

Dynamic changes in the accumulation of metabolites in brackish water clam Corbicula japonica associated with alternation of salinity.

PubMed

Koyama, Hiroki; Okamoto, Seiji; Watanabe, Naoki; Hoshino, Naoshige; Jimbo, Mitsuru; Yasumoto, Ko; Watabe, Shugo

2015-03-01

The brackish water clam Corbicula japonica inhabits rivers and brackish waters throughout Japan where the major fishing grounds in the Ibaraki Prefecture, Japan, are located at the Hinuma Lake and Hinuma River. Water salinity in the Lake Hinuma is low and stable due to the long distance from the Pacific Ocean, whereas that in the downstream of the river varies daily due to a strong effect of tidal waters. In the present study, we dissected the gill and foot muscle of brackish water clam collected from these areas, and subjected them to metabolome analysis by capillary electrophoresis-time-of-flight mass spectrometry. More than 200 metabolites including free amino acids, peptides and organic acids were identified, and their amounts from the foot muscle tend to be higher than those from the gill. The principal component analysis revealed that the amount of each metabolite was different among sampling areas and between the gill and foot muscle, whereas no apparent differences were observed between male and female specimens. When the metabolites in the female clam at high salinity were compared with those at low salinity, concentrations of β-alanine, choline, γ-aminobutyric acid, ornithine and glycine betaine were found to be changed in association with salinity. We also compared various metabolites in relation to metabolic pathways, suggesting that many enzymes were involved in their changes depending on salinity. Copyright © 2014 Elsevier Inc. All rights reserved.

Fauna Europaea: Mollusca – Bivalvia

PubMed Central

2015-01-01

Abstract Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. For the Mollusca-Bivalvia, data from 5 families (Margaritiferidae, Unionidae, Sphaeriidae, Cyrenidae, Dreissenidae) containing 55 species are included in this paper. European freshwater bivalves belong to the Orders Unionoida and Cardiida. All the European unionoids are included in the superfamily Unionoidea, the freshwater mussels or naiads. The European cardiids belong to the following three superfamilies: Cardioidea, Cyrenoidea and Dreissenoidea. Among the Unionoidea there are the most imperilled animal groups on the planet while the Cardioidea includes the cosmopolitan genus Pisidium, the Cyrenoidea the Asiatic clam (Corbicula fluminea) and the Dreissenoidea the famous invasive zebra mussel (Dreissena polymorpha). Basic information is summarized on their taxonomy and biology. Tabulations include a complete list of the current estimated families, genera and species. PMID:26311403

Trace metals in suspended particles, sediments and Asiatic clams (Corbicula fluminea) of the Río de la Plata Estuary, Argentina.

PubMed

Bilos, C; Colombo, J C; Presa, M J

1998-01-01

Suspended particulate matter (SPM), sandy sediments and Asiatic clams were collected at seven sites along 150 km of the Río de la Plata coast to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 7.4-109; Cr: 75-408; Mn: 525-1341 microg(-1)), sediments (Cr: 16-27; Zn: 26-99; Mn: 221-489 microg(-1)) and bivalves (Cd: 0.5-1.9; Ni: 1.3-6.4; Cr: 1.3-11; Mn: 15-81; Cu: 28-89; Zn: 118-316 microg g(-1)) are comparable to those reported for other moderately polluted world rivers. Cu levels in Asiatic clams are among the highest, similar to those reported for heavily polluted sites. SPM Cu and Cr concentrations displayed a clear geographical trend with values increasing with proximity to major urban centers. Sediments showed a less clear pattern possibly due to their coarse nature (>98% sand) and higher proportion of mineral-associated residual metals. The clams showed a complex pattern due to the variability introduced by size-related factors and the natural dynamics of SPM in the estuary. Cr and Mn showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations near the turbidity maximum zone, possibly reflecting enhanced particle retention. Cu, Cd and Ni showed no clear geographical pattern, whereas Zn increased in the clams collected in the most industrialized area. A significant relationship with clam size was observed for Cu (positive) and Zn (negative) suggesting different physiological requirements for both metals with age. A principal component analysis confirmed these geographical and size-related trends.

Bivalve effects on the food web supporting delta smelt - A long-term study of bivalve recruitment, biomass, and grazing rate patterns with varying freshwater outflow

USGS Publications Warehouse

Crauder, Jeff S.; Thompson, Janet K.; Parchaso, Francis; Anduaga, Rosa I.; Pearson, Sarah A.; Gehrts, Karen; Fuller, Heather; Wells, Elizabeth

2016-01-21

At the few stations where Potamocorbula and Corbicula co-occur, it appears that they did not hinder each other’s growth. Both bivalves had large animals at D4, where Corbicula size increased coincident with the presence of Potamocorbula in 1987. Corbicula were observed in wet years prior to Potamocorbula’sinvasion at D7 (Grizzly Bay) and were capable of growing to significant size in wet years (> 20 mm in 1986). 

Seasonal food habits of introduced blue catfish in Lake Oconee, Georgia

USGS Publications Warehouse

Jennings, Cecil A.; Mitchell, Geoffrey E.; Nelson, Chris

2018-01-01

Blue catfish (Ictalurus furcatus) are native to the Coosa River drainage in northwest Georgia but have been widely introduced outside of this range including Lake Oconee, a 7677-ha impoundment on the Oconee River in central Georgia. Blue catfish abundance and growth rates have increased dramatically since their introduction in Lake Oconee, but their food habits are unknown. Therefore, food habits of blue catfish in this impoundment were determined by examining the stomachs of 808 specimens in the reservoir’s upper and lower regions across all seasons from summer 2012 to summer 2013. Diet was summarized using the Relative Importance of specific prey by weight. In the upper region of the reservoir, Asian clams (Corbicula fluminea) were the dominant prey item during the summer (75.7%), fall (66.4%), and winter (37.6%); whereas crappie (Pomoxis spp.) was the dominant prey item in the spring (38.7%). Asian clams also were the dominant prey items in the lower region during the fall (68.4%), winter (33.9%), and spring (36.4%). Blue catfish seemed to feed opportunistically on seasonally abundant prey items in both the upper riverine and lower lacustrine portions of the reservoir. Of the many sportfishes in the reservoir, only crappie was an important prey item, and then only in the upper region during the spring. Our results do not support concerns that blue catfish are an apex predator that would decimate the sportfish assemblage in this recently colonized reservoir.

Toxicokinetics/toxicodynamics links bioavailability for assessing arsenic uptake and toxicity in three aquaculture species.

PubMed

Chen, Wei-Yu; Liao, Chung-Min

2012-11-01

The purpose of this study was to link toxicokinetics/toxicodynamics (TK/TD) and bioavailability-based metal uptake kinetics to assess arsenic (As) uptake and bioaccumulation in three common farmed species of tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), and freshwater clam (Corbicula fluminea). We developed a mechanistic framework by linking damage assessment model (DAM) and bioavailability-based Michaelis-Menten model for describing TK/TD and As uptake mechanisms. The proposed model was verified with published acute toxicity data. The estimated TK/TD parameters were used to simulate the relationship between bioavailable As uptake and susceptibility probability. The As toxicity was also evaluated based on a constructed elimination-recovery scheme. Absorption rate constants were estimated to be 0.025, 0.016, and 0.175 mL g(-1) h(-1) and As uptake rate constant estimates were 22.875, 63.125, and 788.318 ng g(-1) h(-1) for tilapia, milkfish, and freshwater clam, respectively. Here we showed that a potential trade-off between capacities of As elimination and damage recovery was found among three farmed species. Moreover, the susceptibility probability can also be estimated by the elimination-recovery relations. This study suggested that bioavailability-based uptake kinetics and TK/TD-based DAM could be integrated for assessing metal uptake and toxicity in aquatic organisms. This study is useful to quantitatively assess the complex environmental behavior of metal uptake and implicate to risk assessment of metals in aquaculture systems.

[Latin American malacology. Freshwater mollusks from Argentina].

PubMed

Rumi, Alejandra; Gregoric, Diego E Gutiérrez; Núñez, Verónica; Darrigran, Gustavo A

2008-03-01

. Species of sanitary interest are the propagators of: schistosomiasis -Biomphalaria peregrina, B. straminea y B. tenagophila, Planorbidae-, fasciolasis -Lymnaea viatrix and L. columnella, Lymnaeidae- and dermatitis -Chilina gibbosa and C. fluminea, Chilinidae. Invasive species are: Corbicula fluminea (Corbiculidae) and Limnoperna fortunei (Mytilidae). The construction of new areas for the protection and conservation of the high risk endemic species of freshwater molluscs is a priority. It is necessary to give special attention to the species of the patagonic mountain range and of the mesopotamic area of the Del Plata Basin.

Chlordane, DDT, PCB's, and other selected organic compounds in Asiatic clams and yellow bullhead in the Potomac River Basin, 1992

USGS Publications Warehouse

Zappia, Humbert

1996-01-01

Chlordane, DDT (dichlor-diphenyl-trichloroethane), and PCB's (polychlorinated biphenyls) were the most widespread organic contaminants detected during a 1992 survey of aquatic biological tissues in the Potomac River Basin. On the basis of existing U.S. Food and Drug Administration criteria, no new threats to human health were discovered, although chlordane concentrations may pose a threat to fish-eating wildlife. Chlordane exceeded the National Academy of Science and National Academy of Engineering recommended maximum concentration for the protection of fish-eating wildlife at two sites. The survey, conducted by the U.S. Geological Survey's National Water-Quality Assessment Program, sampled Asiatic clams (Corbicula fluminea) and yellow bullhead (Ameiurus natalis) at 16 sites to determine the occurrence and distribution of 29 hydrophobic organic compounds. Thirteen of these organic compounds were detected in the survey. Sites with the greatest number of compounds detected include the Potomac River near Alexandria, Va., with 6 compounds detected in Asiatic clam tissue, and Accotink Creek near Annandale, Va., with 11 compounds in yellow bullhead tissue. Chlordane was detected at six sites, with maximum concentrations of 31.1 ?g/kg (micrograms per kilograms) in Asiatic clam tissue and 127 ?g/kg in yellow bullhead whole-fish tissue. DDT was detected at five sites, with maximum concentrations of 12.9 ?g/kg in Asiatic clam tissue and 7.6 ?g/kg in yellow bullhead whole-fish tissue. PCB's were detected at nine sites, with maximum concentrations of 162 ?g/kg in Asiatic clam tissue and 146 mg/ kg in yellow bullhead whole-fish tissue.

Ecological values of shallow-water habitats: Implications for the restoration of disturbed ecosystems

USGS Publications Warehouse

Lopez, C.B.; Cloern, J.E.; Schraga, T.S.; Little, A.J.; Lucas, L.V.; Thompson, J.K.; Burau, J.R.

2006-01-01

A presumed value of shallow-habitat enhanced pelagic productivity derives from the principle that in nutrient-rich aquatic systems phytoplankton growth rate is controlled by light availability, which varies inversely with habitat depth. We measured a set of biological indicators across the gradient of habitat depth within the Sacramento-San Joaquin River Delta (California) to test the hypothesis that plankton biomass, production, and pelagic energy flow also vary systematically with habitat depth. Results showed that phytoplankton biomass and production were only weakly related to phytoplankton growth rates whereas other processes (transport, consumption) were important controls. Distribution of the invasive clam Corbicula fluminea was patchy, and heavily colonized habitats all supported low phytoplankton biomass and production and functioned as food sinks. Surplus primary production in shallow, uncolonized habitats provided potential subsidies to neighboring recipient habitats. Zooplankton in deeper habitats, where grazing exceeded phytoplankton production, were likely supported by significant fluxes of phytoplankton biomass from connected donor habitats. Our results provide three important lessons for ecosystem science: (a) in the absence of process measurements, derived indices provide valuable information to improve our mechanistic understanding of ecosystem function and to benefit adaptive management strategies; (b) the benefits of some ecosystem functions are displaced by water movements, so the value of individual habitat types can only be revealed through a regional perspective that includes connectedness among habitats; and (c) invasive species can act as overriding controls of habitat function, adding to the uncertainty of management outcomes. ?? 2006 Springer Science+Business Media, Inc.

Using the Asian clam as an indicator of microplastic pollution in freshwater ecosystems.

PubMed

Su, Lei; Cai, Huiwen; Kolandhasamy, Prabhu; Wu, Chenxi; Rochman, Chelsea M; Shi, Huahong

2018-03-01

Bioindicators play an important role in understanding pollution levels, bioavailability and the ecological risks of contaminants. Several bioindicators have been suggested for understanding microplastic in the marine environment. A bioindicator for microplastics in the freshwater environment does not exist. In our previous studies, we found a high frequency of microplastic pollution in the Asian clam (Corbicula fluminea) in Taihu Lake, China. In the present study, we conducted a large-scale survey of microplastic pollution in Asian clams, water and sediment from 21 sites in the Middle-Lower Yangtze River Basin from August to October of 2016. The Asian clam was available in all sites, which included diverse freshwater systems such as lakes, rivers and estuaries. Microplastics were found at concentrations ranging from 0.3-4.9 items/g (or 0.4-5.0 items/individual) in clams, 0.5-3.1 items/L in water and 15-160 items/kg in sediment. Microfibers were the most dominant types of microplastics found, accounting for 60-100% in clams across all sampling sites. The size of microplastics ranged from 0.021-4.83 mm, and microplastics in the range of 0.25-1 mm were dominant. The abundance, size distribution and color patterns of microplastics in clams more closely resembled those in sediment than in water. Because microplastic pollution in the Asian clam reflected the variability of microplastic pollution in the freshwater environments, we demonstrated the Asian clam as an bioindicator of microplastic pollution in freshwater systems, particularly for sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microplastics in Taihu Lake, China.

PubMed

Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

2016-09-01

In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microcystin uptake and biochemical responses in the freshwater clam Corbicula leana P. exposed to toxic and non-toxic Microcystis aeruginosa: Evidence of tolerance to cyanotoxins.

PubMed

Pham, Thanh-Luu; Shimizu, Kazuya; Dao, Thanh-Son; Hong-Do, Lan-Chi; Utsumi, Motoo

2015-01-01

We investigated the accumulation and adverse effects of toxic and non-toxic Microcystis in the edible clam Corbicula leana . Treated clams were exposed to toxic Microcystis at 100 μg of MC (microcystin)-LR eq  L -1 for 10 days. The experimental organism was then placed in toxin-free water and fed on non-toxic Microcystis for the following 10 days for depuration. Filtering rates (FRs) by C. leana of toxic and non-toxic Microcystis and of the green alga Chlorella vulgaris as a control were estimated. Adverse effects were evaluated though the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST). Clam accumulated MCs (up to 12.7 ± 2.5 μg g -1 dry weight (DW) of free MC and 4.2 ± 0.6 μg g -1 DW of covalently bound MC). Our results suggest that although both toxic and non-toxic cyanobacteria caused adverse effects by inducing the detoxification and antioxidant defense system, the clam was quite resistant to cyanotoxins. The estimated MC concentration in C. leana was far beyond the World Health Organization's (WHO) provisional tolerable daily intake (0.04 μg kg -1  day -1 ), suggesting that consuming clams harvested during cyanobacterial blooms carries a high health risk.

Trace elements and organic compounds in streambed sediment and aquatic biota from the Sacramento River Basin, California, October and November 1995

USGS Publications Warehouse

MacCoy, Dorene E.; Domagalski, Joseph L.

1999-01-01

Elevated levels of trace elements and hydrophobic organic compounds were detected in streambed sediments and aquatic biota [Asiatic clam (Corbicula fluminea) or bottom-feeding fish] of the Sacramento River Basin, California, during October and November 1995. Trace elements detected included cadmium, copper, mercury, lead, and zinc. Elevated levels of cadmium, copper, and zinc in the upper Sacramento River are attributed to a mining land use, and elevated levels of zinc and lead in an urban stream, and possibly in the lower Sacramento River, are attributed to urban runoff processes. Elevated levels of mercury in streambed sediment are attributed to either past mercury mining or to the use of mercury in past gold mining operations. Mercury mining was an important land use within the Coast Ranges in the past and gold mining was an important land use of the Sierra Nevada in the past. Mercury was the only trace element found in elevated levels in the tissue of aquatic biota, and those levels also could be attributed to either mining or urban runoff. Hydrophobic organic compounds also were detected in streambed sediments and aquatic biota. The most frequently detected compounds were DDT and its breakdown products, dieldrin, oxychlordane, and toxaphene. Differences were found in the types of compounds detected at agricultural sites and the urban site. Although both types of sites had measurable concentrations of DDT or its breakdown products, the urban site also had measurable concentrations of pesticides used for household pest control. Few semivolatile compounds were detected in the streambed sediments of any site. The semivolatile compound p-cresol, a coal-tar derivative associated with road maintenance, was found in the highest concentration.

Concentrations of metals in aquatic invertebrates from the Ozark National Scenic Riverways, Missouri

USGS Publications Warehouse

Schmitt, Christopher J.; Brumbaugh, William G.; Besser, John M.; May, Thomas W.

2007-01-01

This report summarizes the findings of a study conducted as a pilot for part of a park-wide monitoring program being developed for the Ozark National Scenic Riverways (ONSR) of southeastern Missouri. The objective was to evaluate using crayfish (Orconectes spp.) and Asian clam (Corbicula fluminea) for monitoring concentrations of metals associated with lead-zinc mining. Lead-zinc mining presently (2007) occurs near the ONSR and additional mining has been proposed. Three composite samples of each type (crayfish and Asian clam), each comprising ten animals of approximately the same size, were collected during late summer and early fall of 2005 from five sites on the Current River and Jacks Fork within the ONSR and from one site on the Eleven Point River and the Big River, which are outside the ONSR. The Big River has been contaminated by mine tailings from historical leadzinc mining. Samples were analyzed by inductively coupled plasma mass spectrometry for lead, zinc, cadmium, cobalt, and nickel concentrations. All five metals were detected in all samples; concentrations were greatest in samples of both types from the Big River, and lowest in samples from sites within the ONSR. Concentrations of zinc and cadmium typically were greater in Asian clams than in crayfish, but differences were less evident for the other metals. In addition, differences among sites were small for cobalt in Asian clams and for zinc in crayfish, indicating that these metals are internally regulated to some extent. Consequently, both sample types are recommended for monitoring. Concentrations of metals in crayfish and Asian clams were consistent with those reported by other studies and programs that sampled streams in southeast Missouri.

Mercury bioaccumulation along food webs in temperate aquatic ecosystems colonized by aquatic macrophytes in south western France.

PubMed

Gentès, Sophie; Maury-Brachet, Régine; Guyoneaud, Rémy; Monperrus, Mathilde; André, Jean-Marc; Davail, Stéphane; Legeay, Alexia

2013-05-01

Mercury (Hg) is considered as an important pollutant for aquatic systems as its organic form, methylmercury (MeHg), is easily bioaccumulated and bioamplified along food webs. In various ecosystems, aquatic periphyton associated with macrophyte was identified as an important place for Hg storage and methylation by microorganisms. Our study concerns temperate aquatic ecosystems (South Western France) colonized by invasive macrophytes and characterized by high mercury methylation potentials. This work establishes original data concerning Hg bioaccumulation in organisms (plants, crustaceans, molluscs and fish) from five contrasting ecosystems. For low trophic level species, total Hg (THg) concentrations were low (from 27±2ngTHgg(-1)dw in asiatic clam Corbicula fluminea to 418±114ngTHgg(-1)dw in crayfish Procambarus clarkii). THg concentrations in some carnivorous fish (high trophic level) were close to or exceeded the International Marketing Level (IML) with values ranging from 1049±220ngTHgg(-1)dw in pike perch muscle (Sander lucioperca) to 3910±1307ngTHgg(-1)dw in eel muscle (Anguilla Anguilla). Trophic levels for the individuals were also evaluated through stable isotope analysis, and linked to Hg concentrations of organisms. A significant Hg biomagnification (r(2)= 0.9) was observed in the Aureilhan lake, despite the absence of top predator fish. For this site, Ludwigia sp. periphyton, as an entry point of Hg into food webs, is a serious hypothesis which remains to be confirmed. This study provides a first investigation of Hg transfer in the ecosystems of south western France and allows the assessment of the risk associated with the presence of Hg in aquatic food webs. Copyright © 2013 Elsevier Inc. All rights reserved.

Is the Ghost of Waste Management's Past Coming Back to Haunt Us In Our Seafood?

NASA Astrophysics Data System (ADS)

Rochman, C. M.; Tahir, A.; Serrato, S.; Williams, S.; Baxa, D.; Lam, R.; Teh, C.; Miller, J.; Werorilangi, S.; Teh, S.

2016-02-01

Plastic debris is recognized globally as a persistent contaminant, littered across multiple habitats worldwide. Most striking is its occurrence in wildlife. Plastic has been recovered from hundreds of species across multiple trophic levels and in animals we consider seafood. This has led policy-makers to ask about the extent that our seafood is contaminated with plastic debris and associated contaminants. To help address these policy-relevant and emerging scientific questions, we first measured the simple presence of anthropogenic debris in many different species of fish and one species of shellfish sold as seafood at local fish markets in Half Moon Bay, California, USA and Makassar, Sulawesi, Indonesia. We found anthropogenic debris in roughly 25% of all animals purchased, demonstrating that some seafood items are contaminated with plastic debris, including some that we consume whole (e.g., anchovies and oysters). Next, to understand if plastic debris can act as a vector for organic pollutants to move through the food chain and indirectly into the meat of fish at higher trophic levels, we designed a laboratory dietary exposure to measure the bioaccumulation of sorbed PCBs in Asian clams (Corbicula fluminea) and the biomagnifications in white sturgeon (Acipenser transmontanus). Asian clams were exposed for 30 days to separate treatments of microplastic (polyethylene terephthalate, polyethylene, polyvinyl chloride and polystyrene) with and without sorbed PCBs. Next, diets were formulated using purified ingredients and clams from the first exposure and fed to their predators (sturgeon) for 30 days. Chemical analyses, allowing us to understand how chemical contaminants from plastics move through food chains, will be presented. Combined, this work demonstrates the presence of plastic debris in seafood and will help us understand whether plastic acts as a vector for chemicals to transfer through aquatic foodwebs, including our own.

Sediment toxicity and bioaccumulation of nano and micron-sized aluminum oxide.

PubMed

Stanley, Jacob K; Coleman, Jessica G; Weiss, Charles A; Steevens, Jeffery A

2010-02-01

Nano-aluminum oxide (Al(2)O(3)) is used commercially in coatings and abrasives. Nano-Al(2)O(3) can also be generated through the oxidation of nano-aluminum in military propellants and energetics. The purpose of the present study was to assess toxicity and bioaccumulation of nano-Al(2)O(3) to a variety of sediment organisms (Tubifex tubifex, Hyalella azteca, Lumbriculus variegatus, and Corbicula fluminea). The bioaccumulation and toxicity of nano-Al(2)O(3) was compared with that of micron-sized Al(2)O(3) to investigate potential size-related effects. Results of the present study show species-specific differences in relative bioaccumulation of nano and micron-sized Al(2)O(3). Significant toxic effects (survival and growth) were observed in H. azteca testing, but only at high concentrations unlikely to be found in the environment. Nano-Al(2)O(3) was found to be more toxic than micron-sized Al(2)O(3) to H. azteca survival in a 14-d study in which organisms were in direct contact with a thin layer of 625 or 2,500 mg of Al(2)O(3) dispersed on the surface of either sediment or sand. A significant growth effect was also observed for nano but not micron-sized Al(2)O(3) at the highest treatment level tested (100 g/kg Al(2)O(3)) in a 10-d H. azteca bioassay in which Al(2)O(3) was homogenized with sediment. However, differences in measured sediment Al concentrations (micron-sized = 55.1 [+/-0.6] g/kg Al; nano-sized = 66.2 [+/-0.6] g/kg Al) in the nano and micron-sized Al(2)O(3) preclude direct comparison of the toxicity of these two treatments based on particle size. Copyright 2009 SETAC.

Temporally intensive study of trace metals in sediments and bivalves from a large river-estuarine system: Suisun Bay/delta in San Francisco Bay

USGS Publications Warehouse

Luoma, S.N.; Dagovitz, R.; Axtmann, E.

1990-01-01

Distributions in time and space of Ag, Cd, Cr, Cu, Pb and Zn were determined in fine-grained sediments and in the filter-feeding bivalve Corbicula sp. of Suisun Bay/delta at the mouth of the Sacramento and San Joaquin Rivers in North San Francisco Bay. Samples were collected from seven stations at near-monthly intervals for 3 years. Aggregated data showed little chronic contamination with Ag, Zn and Pb in the river and estuary. Substantial chronic contamination with Cd, Cu and Cr in Suisun Bay/delta occurred, especially in Corbicula, compared with the lower San Joaquin River. Salinity appeared to have secondary effects, if any, on metal concentrations in sediments and metal bioavailability to bivalves. Space/time distributions of Cr were controlled by releases from a local industry. Analyses of time series suggested substantial inputs of Cu might originate from the Sacramento River during high inflows to the Bay, and Cd contamination had both riverine and local sources. Concentrations of metals in sediments correlated with concentrations in Corbicula only in annually or 3-year aggregated data. Condition index for Corbicula was reduced where metal contamination was most severe. The biological availability of Cu and Cd to benthos was greater in Suisun Bay than in many other estuaries. Thus small inputs into this system could have greater impacts than might occur elsewhere; and organisms were generally more sensitive indicators of enrichment than sediments in this system.

Field Validation of Toxicity Tests to Evaluate the Potential for Beneficial Use of Produced Water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph Bidwell; Jonathan Fisher; Naomi Cooper

2008-03-31

This study investigated potential biological effects of produced water contamination derived from occasional surface overflow and possible subsurface intrusion at an oil production site along the shore of Skiatook Lake, Oklahoma. We monitored basic chemistry and acute toxicity to a suite of standard aquatic test species (fathead minnow-Pimephales promelas, Daphnia pulex, Daphnia magna, and Ceriodaphnia dubia) in produced water and in samples taken from shallow groundwater wells on the site. Toxicity identification evaluations and ion toxicity modeling were used to identify toxic constituents in the samples. Lake sediment at the oil production site and at a reference site were alsomore » analyzed for brine intrusion chemically and by testing sediment toxicity using the benthic invertebrates, Chironomus dilutus, and Hyallela azteca. Sediment quality was also assessed with in situ survival and growth studies with H. azteca and the Asian clam, Corbicula fluminea, and by benthic macroinvertebrate community sampling. The produced water was acutely toxic to the aquatic test organisms at concentrations ranging from 1% to 10% of the whole produced water sample. Toxicity identification evaluation and ion toxicity modeling indicated major ion salts and hydrocarbons were the primary mixture toxicants. The standardized test species used in the laboratory bioassays exhibited differences in sensitivity to these two general classes of contaminants, which underscores the importance of using multiple species when evaluating produced water toxicity. Toxicity of groundwater was greater in samples from wells near a produced water injection well and an evaporation pond. Principle component analyses (PCA) of chemical data derived from the groundwater wells indicated dilution by lake water and possible biogeochemical reactions as factors that ameliorated groundwater toxicity. Elevated concentrations of major ions were found in pore water from lake sediments, but toxicity from these ions

Interpretation of body residues for natural resources damage assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kubitz, J.A.; Markarian, R.K.; Lauren, D.J.

1995-12-31

A 28-day caged mussel study using Corbicula sp. was conducted on Sugarland Run and the Potomac River following a spill of No. 2 fuel oil. In addition, resident Corbicula sp. from the Potomac River were sampled at the beginning and end of the study. The summed body residues of 39 polycyclic aromatic hydrocarbons (PAHs) ranged from 0.56 to 41 mg/kg dry weight within the study area. The summed body residues of the 18 PAHs that are routinely measured in the national oceanic and Atmospheric Administration Status and Trends Program (NST) ranged from 0.5 to 20 mg/kg dry weight for musselsmore » in this study. These data were similar to summed PAH concentrations reported in the NST for mussels from a variety of US coastal waters, which ranged from 0.4 to 24.5 mg/kg dry weight. This paper will discuss interpretation of PAH residues in Corbicula sp. to determine the spatial extent of the area affected by the oil spill. The toxicological significance of the PAH residues in both resident and caged mussels will also be presented.« less

Predation on exotic zebra mussels by native fishes: Effects on predator and prey

USGS Publications Warehouse

Magoulick, D.D.; Lewis, L.C.

2002-01-01

1. Exotic zebra mussels, Dreissena polymorpha, occur in southern U.S. waterways in high densities, but little is known about the interaction between native fish predators and zebra mussels. Previous studies have suggested that exotic zebra mussels are low profitability prey items and native vertebrate predators are unlikely to reduce zebra mussel densities. We tested these hypotheses by observing prey use of fishes, determining energy content of primary prey species of fishes, and conducting predator exclusion experiments in Lake Dardanelle, Arkansas. 2. Zebra mussels were the primary prey eaten by 52.9% of blue catfish, Ictalurus furcatus; 48.2% of freshwater drum, Aplodinotus grunniens; and 100% of adult redear sunfish, Lepomis microlophus. Blue catfish showed distinct seasonal prey shifts, feeding on zebra mussels in summer and shad, Dorosoma spp., during winter. Energy content (joules g-1) of blue catfish prey (threadfin shad, Dorosoma petenense; gizzard shad, D. cepedianum; zebra mussels; and asiatic clams, Corbicula fluminea) showed a significant species by season interaction, but shad were always significantly greater in energy content than bivalves examined as either ash-free dry mass or whole organism dry mass. Fish predators significantly reduced densities of large zebra mussels (>5 mm length) colonising clay tiles in the summers of 1997 and 1998, but predation effects on small zebra mussels (???5 mm length) were less clear. 3. Freshwater drum and redear sunfish process bivalve prey by crushing shells and obtain low amounts of higher-energy food (only the flesh), whereas blue catfish lack a shell-crushing apparatus and ingest large amounts of low-energy food per unit time (bivalves with their shells). Blue catfish appeared to select the abundant zebra mussel over the more energetically rich shad during summer, then shifted to shad during winter when shad experienced temperature-dependent stress and mortality. Native fish predators can suppress adult zebra

Multi-contamination (heavy metals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons) of littoral sediments and the associated ecological risk assessment in a large lake in France (Lake Bourget).

PubMed

Lécrivain, Nathalie; Aurenche, Vincent; Cottin, Nathalie; Frossard, Victor; Clément, Bernard

2018-04-01

The lake littoral sediment is exposed to a large array of contaminants that can exhibit significant spatial variability and challenge our ability to assess contamination at lake scale. In this study, littoral sediment contamination was characterized among ten different sites in a large peri-alpine lake (Lake Bourget) regarding three groups of contaminants: 6 heavy metals, 15 polycyclic aromatic hydrocarbons and 7 polychlorinated biphenyls. The contamination profiles significantly varied among sites and differed from those previously reported for the deepest zone of the lake. An integrative approach including chemical and biological analyses was conducted to relate site contamination to ecological risk. The chemical approach consisted in mean PEC quotient calculation (average of the ratios of the contaminants concentration to their corresponding Probable Effect Concentration values) and revealed a low and heterogeneous toxicity of the contaminant mixture along the littoral. Biological analysis including both laboratory (microcosm assays) and in situ (Acetylcholine Esterase (AChE) and Glutathione S-Transferase (GST) activity measurements) experiments highlighted significant differences among sites both in the field and in laboratory assays suggesting a spatial variation of the biota response to contamination. Linear regressions were performed between mean PEC quotients and biological results to assess whether littoral ecological risk was explained by the contamination profiles. The results highly depended on the study benthic or pelagic compartment. Regarding autochthonous Corbicula fluminea, no significant relationship between mean PEC quotients and biomarker activity was found while a significant increase in AChE was observed on autochthonous chironomids, suggesting different stress among benthic organisms. Both AChE and GST in caged pelagic Daphnia magna showed a significant positive relationship with mean PEC quotients. This study underlines the importance of

Protective effects of a traditional Chinese herbal formula Jiang-Xian HuGan on Concanavalin A-induced mouse hepatitis via NF-κB and Nrf2 signaling pathways.

PubMed

Tang, Huan-Huan; Li, Hai-Long; Li, Yue-Xuan; You, Yan; Guan, Yun-Yun; Zhang, Su-Lin; Liu, Li-Xin; Bao, Wei-Lian; Zhou, Yong; Shen, Xiao-Yan

2018-05-10

Jiang-Xian HuGan (JXHG) formulated by five natural products including Freshwater clam (Corbicula fluminea), Curcuma longa L., Ligustrum lucidum, Eclipta prostrata (L.) L. and Paeonia lactiflora Pall., has exhibited a great hepatoprotective effect. We investigated the effect of JXHG on concanavalin A (ConA)-induced acute live injury in mice, and to elucidate its underlying molecular mechanisms. Jiangkanling Capsule (900 mg/kg), low-dose JXHG (LJXHG, 700 mg/kg), high-dose JXHG (HJXHG, 1400 mg/kg) were administered to mice by oral gavage daily for 20 days prior to a single intravenous injection of ConA (20 mg/kg). Liver injury was evaluated by measuring the serum levels of enzymes and cytokines as well as liver histological analysis. We also measured the hepatic expression of cytokines at mRNA levels and the proteins related to NF-κB and Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling pathways. Our results showed that JXHG pretreatment significantly alleviated ConA-induced live injury as evidenced by decreased serum levels of glutamic-pyruvic transaminase (ALT) and glutamic oxalacetic transaminase (AST), and reduced hepatocyte apoptosis and mortality. Furthermore, JXHG was able to significantly reduce the serum levels of proinflammatory cytokines, down-regulate the mRNA expression of interleukin-6 (IL-6) and interferon-γ (IFN-γ), and up-regulate IL-10 as well as superoxide-dimutase-1 (SOD1), glutathione reductase (GSR) and Glutathione peroxidase 2 (GPX2) mRNA in the liver tissues after Con A injection. In addition, JXHG pretreatment dramatically suppressed the phosphorylation of NF-κB p65 (p65), increased Nrf2 expression, and decreased the expression ratio of cleaved caspase-3/caspase-3 in liver tissues. These results suggest that JXHG protects against ConA-induced acute live injury through inhibiting NF-κB mediated inflammatory pathway and promoting Nrf2 mediated anti-oxidative stress signaling pathway. Copyright © 2018 Elsevier B.V. All

Temperature effects on biomass, geosmin, and 2-methylisoborneol production and cellular activity by Nocardia spp. and Streptomyces spp. isolated from rainbow trout recirculating aquaculture systems

USDA-ARS?s Scientific Manuscript database

Isolates of Nocardia cummidelens, Nocardia fluminea, Streptomyces albidoflavus, and Streptomyces luridiscabiei attributing to geosmin-related off-flavor in rainbow trout (Oncorhynchus mykiss) raised in recirculating aquaculture systems (RAS) were evaluated for the effect of temperature (10-30 degree...

Assessing off-site impacts of wildfires on aquatic organisms using in-situ assays

NASA Astrophysics Data System (ADS)

Ré, Ana; Saraiva, MariaJoão; Puga, João; Campos, Isabel; Pereira, Joana; Keizer, Jacob; Goncalves, Fernando; Abrantes, Nelson

2017-04-01

Wildfires have been recognized as an important source of diffuse pollution to aquatic systems, particularly through the production and transport of pyrolytic substances such as polycyclic aromatic hydrocarbons (PAHs) and metals associated to ash/soil loads. However, the effects of these compounds from recently burnt areas on the aquatic biota have been largely ignored. Hence, the main goal of this study was to assess the ecotoxicological effects of wildfires in aquatic systems through the use of in situ experiments. In this sense, five sites were selected in a catchment partially burnt: two in the main water course - Ceira river (Miranda do Corvo, Portugal), being one located upstream (RUS) and the other downstream (RDS) the burnt area; two in tributary streams within the burnt area (SUS and SDS); and finally one in a stream located in the unburnt part of the catchment (CS). During the first post-fire rainfall events, distinct organisms, including the water flea Daphnia magna, the freshwater shrimp Atyaephyra desmaresti, the freshwater clam Corbicula fluminea and the mosquitofish Gambusia holbrooki were exposed in situ, in all five sites, using dedicated test chambers. After four days of field exposition, the mortality and post-exposure feeding inhibition were evaluated. Feeding depression after exposure time was selected as a sub-lethal endpoint because it is a quick, sensitive and ecologically relevant indicator of toxic stress. The results showed negligible mortality for all the species and sites, thus lethality was not sensitive to discern impacts among the assessed sites. Conversely, the sub-lethal post-exposure feeding inhibition endpoint, revealed a decrease of feeding rate, in streams within the burnt area (SUS and SDS), that seemed to be the most affected places in the study area. Conversely, the sites outside the burnt area, both on river (RUS) and on the stream (CS), showed no adverse effects in this endpoint. Hence, the current results pointed-out that

Water-quality assessment of the Ozark Plateaus study unit, Arkansas, Kansas, Missouri, and Oklahoma; organic compounds in surface water, bed sediment, and biological tissue, 1992-95

USGS Publications Warehouse

Bell, Richard W.; Davis, Jerri V.; Femmer, Suzanne R.; Joseph, Robert L.

1997-01-01

pesticide detections (13). Seventeen other sites had samples with six or more pesticide detections. Analysis of pesticide data collected at surface-water sites indicates that the largest variety of different pesticides detected (18) was in small, agricultural drainage basins; the largest percentage of detections of a single pesticide (about 80) was in medium, agricultural basins. Pesticide concentrations were small, and in most cases, at or near the detection limit. Maximum concentrations ranged from 0.001 to 0.007 micrograms per liter (mg/L) at small, forest sites; 0.001 to 0.029 mg/L at medium, forest sites; 0.001 to 0.079 mg/L at small, agricultural sites; and 0.003 to 0.29 mg/L at medium, agricultural sites. Pesticides were detected significantly more often in medium, agricultural basins in the Springfield Plateau. The most commonly detected (13 samples) organic compound in bed sediment, in concentrations noticeably above background levels, was 2,6-dimethylnaphthalene; the maximum concentration of 2,6-dimethylnaphthalene was 130 micrograms per kilogram. Seventeen or more compounds were detected in bed-sediment samples collected at three sites. Four compounds were detected in biological-tissue samples: p,p'-DDT in Corbicula fluminea (Asiatic clam) tissue collected at the Osage River near St. Thomas, Mo. and cis-chlordane, trans-chlordane, and trans-nonachlor in C. fluminea tissue collected at the James River near Boaz, Mo. Organic compounds collected at surface-water, bed-sediment, or biological-tissue sampling sites were not detected in concentrations that exceeded any health criteria or standards. Based on this information, organic compounds do not pose any widespread or persistent problems in the study unit.

The use of polliniferous resources by Melipona capixaba, an endangered stingless bee species.

PubMed

Serra, Bruna Danielle Vieira; da Luz, Cynthia Fernandes Pinto; Campos, Lucio Antonio de Oliveira

2012-01-01

Abstract Pollen types present in samples from corbiculae of Melipona capixaba (Moure and Camargo) (Hymenoptera: Apidae: Meliponina) worker bees were analyzed, as well as pollen samples from food pots inside the hives in three sites located at the bees' original habitat. The aim was to find out the sources used as a trophic resource by this species. The dominant pollen grains in the spectrum of the samples belonged to the families Myrtaceae and Melastomataceae. Eucalyptus was the most frequent pollen type in the corbiculae in Conceição do Castelo municipality; Eucalyptus, Myrcia, and Melastomatacea/Combretaceae in the Fazenda do Estado district; and Eucalyptus and Myrcia in the São Paulo de Aracê district, both in the Domingos Martins municipality. Eucalyptus and Melastomataceae/Combretaceae were the predominant pollen types in the food pots. Eucalyptus was the most prevalent type all year round or most of the year. The most common pollen types in the months that Eucalyptus was not present or dominant in the samples were of remaining native forest species, "ruderal" (field) plants, fruit-bearing plants, and introduced ornamental plants.

Associations among land-use, habitat characteristics, and invertebrate community structure in nine streams on the island of Oahu, Hawaii

USGS Publications Warehouse

Brasher, Anne M.D.; Wolff, Reuben H.; Luton, Corene D.

2003-01-01

channelized urban streams although no native molluscs were collected during this study. The most abundant molluscs were pan-tropical thiarid snails, the introduced clam Corbicula fluminea, and the limpet Ferrissia sharpi. Two native and four introduced species of Crustacea were collected at the sampling sites. To effectively manage Hawaiian watersheds for native species and the communities they form, the ways in which these species respond to human-induced changes needs to be understood. This report provides important information describing the usefulness of invertebrates as indicators of stream quality conditions and how an integrated assessment of stream quality will allow for the development of appropriate monitoring and management strategies.

Survey of chemical contaminants in the Hanalei River, Kaua'i, Hawai'i, 2001

USGS Publications Warehouse

Orazio, Carl E.; May, Thomas W.; Gale, Robert W.; Meadows, John C.; Brumbaugh, William G.; Echols, Kathy R.; Steiner, William W.M.; Berg, Carl J.

2007-01-01

The Hanalei River on the island of Kaua'i in Hawai'i was designated an American Heritage River in 1998, providing special attention to natural resource protection, economic revitalization, and historic and cultural preservation. Agricultural, urban, and tourism-related activities are potential sources of contamination within the Hanalei River watershed. The objective of this study was to measure certain persistent organic chemicals and elements in the Hanalei River.During a relatively low-flow period in December of 2001, samples of native Akupa sleeper fish (Eleotris sandwicensis), freshwater Asian clam (Corbicula fluminea), giant mud crab (Scylla serrata), surface water, and stream bed sediment were collected from a lower estuarine reach of the river near its mouth at Hanalei Bay and from an upper reach at the Hanalei National Wildlife Refuge. Samples were analyzed for residues of urban and agricultural chemicals including organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and elements (including mercury, lead, cadmium, arsenic, and selenium). Organic contaminants were extracted from the samples with solvent, enriched, and then analyzed by gas chromatographic analysis with electron capture or mass spectrometric detection. Samples were acid-digested for semi-quantitative analysis for elements by inductively-coupled plasma-mass spectrometry and for quantitative analysis by atomic absorption spectrophotometry.Concentrations of organochlorine pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in biota, surface water, and bed sediment sampled from the Hanalei River ranged from nondetectable to very low levels. Polychlorinated biphenyls were below detection in all samples. Dieldrin, the only compound detected in the water samples, was present at very low concentrations of 1-2 nanograms per liter. Akupa sleeper fish and giant mud crabs from the lower reach ranged from 1 to 5 nanograms per gram (wet weight

Demonstration and Validation of Enhanced Monitored Natural Recovery at DoD Sites

DTIC Science & Technology

2017-08-11

was run on the ANOVA results. The C . fluminea dataset was more robust, therefor it was possible to control for this spatial DDX variability. Total...Ranasinghe, L. C . Scott, and R. J . Llansó. 2002. Statistical verification of the Chesapeake Bay Benthic Index of Biotic Integrity. Envirometrics...Technical Report 1960. Brannon, J . M., R. E. Hoeppel, T. C . Sturgis, I. Smith, and D. Gunnison. 1985. Effectiveness of Capping in Isolating

The Use of Polliniferous Resources by Melipona capixaba, an Endangered Stingless Bee Species

PubMed Central

Serra, Bruna Danielle Vieira; da Luz, Cynthia Fernandes Pinto; Campos, Lucio Antonio de Oliveira

2012-01-01

Pollen types present in samples from corbiculae of Melipona capixaba (Moure and Camargo) (Hymenoptera: Apidae: Meliponina) worker bees were analyzed, as well as pollen samples from food pots inside the hives in three sites located at the bees’ original habitat. The aim was to find out the sources used as a trophic resource by this species. The dominant pollen grains in the spectrum of the samples belonged to the families Myrtaceae and Melastomataceae. Eucalyptus was the most frequent pollen type in the corbiculae in Conceição do Castelo municipality; Eucalyptus, Myrcia, and Melastomatacea/Combretaceae in the Fazenda do Estado district; and Eucalyptus and Myrcia in the São Paulo de Aracê district, both in the Domingos Martins municipality. Eucalyptus and Melastomataceae/Combretaceae were the predominant pollen types in the food pots. Eucalyptus was the most prevalent type all year round or most of the year. The most common pollen types in the months that Eucalyptus was not present or dominant in the samples were of remaining native forest species, “ruderal” (field) plants, fruit-bearing plants, and introduced ornamental plants. PMID:23464528

Homestead Valley, California, aftershocks (March 17-18, 1979) recorded on portable seismographs

USGS Publications Warehouse

Perry-Huston, Sue; Eberhart-Phillips, Donna

1994-01-01

A method for the determination of chlorinated organic compounds in aquatic tissue by dual capillary-column gas chromatography with electron- capture detection is described. Whole-body-fish or corbicula tissue is homogenized, Soxhlet extracted, lipid removed by gel permeation chromatography, and fractionated using alumina/silica adsorption chromatography. The extracts are analyzed by dissimilar capillary-column gas chromatography with electron-capture detection. The method reporting limits are 5 micrograms per kilogram (ug/kg) for chlorinated compounds, 50 ug/kg for polychlorinated biphenyls, and 200 ug/kg for toxaphene.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chlorinated pesticides in aquatic tissue by capillary-column gas chromatography with electron-capture detection

USGS Publications Warehouse

Leiker, Thomas J.; Madsen, J.E.; Deacon, J.R.; Foreman, W.T.

1995-01-01

A method for the determination of chlorinated organic compounds in aquatic tissue by dual capillary-column gas chromatography with electron-capture detection is described. Whole-body-fish or corbicula tissue is homogenized, Soxhlet extracted, lipid removed by gel permeation chromatography, and fractionated using alumina/silica adsorption chromatography. The extracts are analyzed by dissimilar capillary-column gas chromatography with electron-capture detection. The method reporting limits are 5 micrograms per kilogram (μg/kg) for chlorinated compounds, 50 μg/kg for polychlorinated biphenyls, and 200 μg/kg for toxaphene.

Specialized and Generalized Pollen-Collection Strategies in an Ancient Bee Lineage.

PubMed

Wappler, Torsten; Labandeira, Conrad C; Engel, Michael S; Zetter, Reinhard; Grímsson, Friðgeir

2015-12-07

Iconic examples of insect pollination have emphasized narrowly specialized pollinator mutualisms such as figs and fig wasps and yuccas and yucca moths. However, recent attention by pollination ecologists has focused on the broad spectra of pollinated plants by generalist pollinators such as bees. Bees have great impact for formulating hypotheses regarding specialization versus generalization in pollination mutualisms. We report the pollination biology of six northern European species of an extinct tribe of pollen-basket-bearing apine bees, Electrapini, of early-middle Eocene age, examined from two deposits of 48 and 44 million years in age. These bees exhibit a pattern of generalized, incidental pollen occurring randomly on their heads, thoraces, and abdomens, obtained from diverse, nectar-bearing plants. By contrast, a more restricted suite of pollen was acquired for metatibial pollen baskets (corbiculae) of the same bee taxa from a taxonomically much narrower suite of arborescent, evergreen hosts with uniform flower structure. The stereotyped plant sources of the specialist strategy of pollen collection consisted of pentamerous, radially symmetrical flowers with a conspicuous gynoecium surrounded by prominent nectar reward, organized in structurally similar compound inflorescences. Pollen specialization in bees occurs not for efficient pollination but rather in the corbiculate Electrapini as food for bee larvae (brood) and involves packing corbiculae with moistened pollen that rapidly loses viability with age. This specialist strategy was a well-developed preference by the early Eocene, providing a geochronologic midpoint assessment of bee pollen-collection strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Temporal and spatial assessment of water quality, physical habitat, and benthic communities in an impaired agricultural stream in California's San Joaquin Valley.

PubMed

Hall, Lenwood W; Killen, William D

2005-01-01

The goal of this study was to characterize and discuss the relationships among water quality, physical habitat, and benthic community data collected annually over a three-year period (2000--2002) in an impaired agricultural stream (Orestimba Creek) in California's San Joaquin River watershed. Conductivity, pH, and turbidity were the most important water quality conditions influencing the various benthic metrics. Significantly higher flow conditions and lower dissolved oxygen values were reported in Orestimba Creek in 2001; increased turbidity conditions were reported in 2002. Channel alteration, riparian buffer, sediment deposition, and channel flow were the most important physical habitat metrics influencing the various benthic metrics. Higher total physical habitat scores were reported in 2001 when compared with 2002. The most dominant benthic taxa collected during all three years of sampling were oligochaetes and chironomids. Oligochaetes are found in stressful environments while chironomids can be either sensitive or tolerant to environmental stressors depending on the species. Populations of both daphnids and the exotic clam Corbicula were reported to increase over time. Both of these taxa are generally tolerant to most types of environmental degradation. The exception is that daphnids are highly sensitive to organophosphate insecticides. The % filterers increased over time, which suggests an increase in environmental disturbance. The % collectors decreased from 2000 to 2002, which suggests an improvement in environmental conditions. The presence of approximately 100 taxa in Orestimba Creek during each of the three years of sampling implies that benthic communities in this stream are fairly diverse, considering their ephemeral environment, but without a clear definition of benthic community expectations based on established referenc conditions it is unknown if this water body is actually impaired.

Power, Influence Tactics, and Influence Processes in Virtual Teams

ERIC Educational Resources Information Center

Boughton, Marla

2011-01-01

Current studies of power, influence tactics, and influence processes in virtual teams assume that these constructs operate in a similar manner as they do in the face-to-face (FtF) environment. However, the virtual context differs from the FtF environment on a variety of dimensions, such as the availability of status cues. The differences between…

Influenced but unaware: social influence on alcohol drinking among social acquaintances.

PubMed

Dallas, Rebecca; Field, Matt; Jones, Andrew; Christiansen, Paul; Rose, Abi; Robinson, Eric

2014-05-01

Drinking partners may be influenced by each other's alcohol consumption. However, these effects have only been shown in artificially created social pairings and typically among same-sex young adults. Here, we test whether similarly strong influence effects occur among "real" pairs of social acquaintances (friends and partners) and whether people are aware of this influence on their alcohol consumption. Forty-six pairs of social acquaintances aged between 19 and 60 years old participated in a between-subjects experiment, in a semi-naturalistic bar laboratory setting. One member of each pair (the confederate) was randomly selected and asked to consume only alcoholic (alcohol condition) or soft drinks (nonalcohol condition), while the pair completed a game together in a bar setting. The other participant (naïve) was unaware of these drinking instructions. Postconsumption, we measured the extent to which naïve participants believed that their partner had influenced their own drinking behavior. A large effect of condition on alcohol consumption was observed, χ² (2) = 15.8, p < 0.001, Cramer's V = 0.59, whereby the number of alcoholic drinks selected by naïve participants in the alcohol confederate condition was significantly greater than in the nonalcohol confederate condition. The majority of naïve participants (81%) also tended to be unaware that their partner had influenced their alcohol consumption. Social acquaintances are influenced by each other's alcohol consumption and may not be aware of this influence on their behavior. Copyright © 2014 by the Research Society on Alcoholism.

Social influence and obesity.

PubMed

Hammond, Ross A

2010-10-01

To review a selection of research published in the last 12 months on the role of social influence in the obesity epidemic. Recent papers add evidence to previous work linking social network structures and obesity. Social norms, both eating norms and body image norms, are identified as one major source of social influence through networks. Social capital and social stress are additional types of social influence. There is increasing evidence that social influence and social network structures are significant factors in obesity. Deeper understanding of the mechanisms of action and dynamics of social influence, and its link with other factors involved in the obesity epidemic, is an important goal for further research.

Advertising influences on young children's food choices and parental influence.

PubMed

Ferguson, Christopher J; Muñoz, Monica E; Medrano, Maria R

2012-03-01

To evaluate whether advertising for food influences choices made by children, the strength of these influences, and whether they might be easily undone by parental influences. Children between 3 and 8 years of age (n=75) were randomized to watch a series of programs with embedded commercials. Some children watched a commercial for a relatively healthy food item, the other children watched a commercial for a less healthy item, both from the same fast-food company. Children were also randomized either to receive parental encouragement to choose the healthy item or to choose whichever item they preferred. Results indicated that children were more likely to choose the advertised item, despite parental input. Parental input only slightly moderated this influence. Although advertising impact on children's food choices is moderate in size, it appears resilient to parental efforts to intervene. Food advertisements directed at children may have a small but meaningful effect on their healthy food choices. Copyright © 2012 Mosby, Inc. All rights reserved.

Age-related differences in social influence on risk perception depend on the direction of influence.

PubMed

Knoll, Lisa J; Leung, Jovita T; Foulkes, Lucy; Blakemore, Sarah-Jayne

2017-10-01

Adolescents are particularly susceptible to social influence. Here, we investigated the effect of social influence on risk perception in 590 participants aged eight to fifty-nine-years tested in the United Kingdom. Participants rated the riskiness of everyday situations, were then informed about the rating of these situations from a (fictitious) social-influence group consisting of teenagers or adults, and then re-evaluated the situation. Our first aim was to attempt to replicate our previous finding that young adolescents are influenced more by teenagers than by adults. Second, we investigated the social-influence effect when the social-influence group's rating was more, or less, risky than the participants' own risk rating. Younger participants were more strongly influenced by teenagers than by adults, but only when teenagers rated a situation as more risky than did participants. This suggests that stereotypical characteristics of the social-influence group - risk-prone teenagers - interact with social influence on risk perception. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Peer Influence and Recovery

ERIC Educational Resources Information Center

Collier, Crystal; Simpson, Shelly; Najera, John; Weiner, Lauren

2012-01-01

Research has shown that peer influence can be negative, by increasing the likelihood that a youth will engage in high-risk behaviors and make risky decisions. However, peer influence can also be positive and protect a youth from these same high-risk activities. This article examines the extent of peer influence and then describes the Alternative…

Open to Influence: What Counts as Academic Influence in Scholarly Networked "Twitter" Participation

ERIC Educational Resources Information Center

Stewart, Bonnie

2015-01-01

Within the academy, signals of a scholar's academic influence are made manifest in indices like the "h"-index, which rank output. In open scholarly networks, however, signals of influence are less codified, and the ways in which they are enacted and understood have yet to be articulated. Yet the influence scholars cultivate in open…

Orientation on understanding interpersonal influence.

PubMed

Strickland, B; Arnn, J

1977-09-01

Everyone influences and is influenced by others. Are you satisfied with the impact your influence has on others? If not, it can be changed by examining and working on the dimensions of your "style of influence," such as activity, visibility, involvement, and productivity. The author analyzes some of the opposites on a spectrum or "wheel of influence," showing how they may be melded by moderation to achieve the kind of impact you may wish. For instance, there is the analyzer vs. the performer, the leader vs. the follower, the experimenter vs. the organizer, and the asserter vs. the listener. As modes of influence, extremes in any dimension are self-defeating, but by balancing aspects of both sides, desirable "compromises" can be developed. Should you wish to change your style of influence, helfpful procedures to follow are suggested, which, hopefully, will result in satisfying interpersonal relationships and understanding.

Having influence: faculty of color having influence in schools of nursing.

PubMed

Hassouneh, Dena; Lutz, Kristin F

2013-01-01

Faculty of color (FOC) play an important role in mentoring students and other FOC in schools of nursing. However, the unique nature of mentoring that FOC provide, which includes transmission of expert knowledge of the operations of racism in nursing academe, is not well understood. Furthermore, the influence FOC have on school cultures has not been well documented. To address this gap in knowledge we conducted a critical grounded theory study with 23 FOC in predominately Euro-American schools of nursing. Findings indicate that FOC Having Influence is a key process that explicates the influence FOC wield, exposing their work, which is often taken for granted, hidden, and, unacknowledged. FOC Having Influence occurred in two areas: 1) the survival and success of students and FOC and 2) shaping practices in schools of nursing and impacting health in communities. Implications for educational practice and future research are presented, based on study findings. Copyright © 2013 Elsevier Inc. All rights reserved.

Identifying influencers from sampled social networks

NASA Astrophysics Data System (ADS)

Tsugawa, Sho; Kimura, Kazuma

2018-10-01

Identifying influencers who can spread information to many other individuals from a social network is a fundamental research task in the network science research field. Several measures for identifying influencers have been proposed, and the effectiveness of these influence measures has been evaluated for the case where the complete social network structure is known. However, it is difficult in practice to obtain the complete structure of a social network because of missing data, false data, or node/link sampling from the social network. In this paper, we investigate the effects of node sampling from a social network on the effectiveness of influence measures at identifying influencers. Our experimental results show that the negative effect of biased sampling, such as sample edge count, on the identification of influencers is generally small. For social media networks, we can identify influencers whose influence is comparable with that of those identified from the complete social networks by sampling only 10%-30% of the networks. Moreover, our results also suggest the possible benefit of network sampling in the identification of influencers. Our results show that, for some networks, nodes with higher influence can be discovered from sampled social networks than from complete social networks.

Understanding Influence within the Context of Nursing: Development of the Adams Influence Model Using Practice, Research, and Theory.

PubMed

Adams, Jeffrey M; Natarajan, Sudha

2016-01-01

Acquiring influence, and knowing how to use it, is a required competency for nurse leaders, yet the concept of influence and how it works is not well described in the nursing literature. In this article, the authors examine what is known about influence and present an influence model specific to nurse leaders. The Adams Influence Model was developed through an iterative process and is based on a comprehensive review of the influence literature, expert commentary, multiple pilot studies, evaluation of nursing theories, and validation by an external data source. Rather than defining "how to" influence, the model serves as a guide for personal reflection, helping nurse leaders understand and reflect on the influence process and factors, tactics, and strategies they can use when seeking to influence others.

Sibling influences on prosocial behavior.

PubMed

Hughes, Claire; McHarg, Gabrielle; White, Naomi

2018-04-01

Sibling relationships are characterized by familiarity and emotional intensity. Alongside frequent shared play, sibling interactions feature complementary interactions (e.g. teaching, caregiving) reflecting age-related asymmetries in socio-cognitive skills. These aspects may underpin sibling influences on prosocial behavior: theoretical accounts of social influences on prosocial behavior highlight emotion sharing, goal alignment, the intrinsically rewarding nature of social interaction, and scaffolding of social norms. Taking a fine-grained approach to prosocial behavior, we examine these processes in relation to sibling influences on children's comforting, sharing, and helping. Emergent themes include: developmental change in the nature of sibling influences on prosocial behavior, the need to consider sibling influences in the wider family context, and the importance of individual differences in the quality of sibling relationships. Copyright © 2017 Elsevier Ltd. All rights reserved.

Is All Formative Influence Immoral?

ERIC Educational Resources Information Center

Tillson, John

2018-01-01

Is it true that all formative influence is unethical, and that we ought to avoid influencing children (and indeed anyone at all)? There are more or less defensible versions of this doctrine, and we shall follow some of the strands of argument that lead to this conclusion. It seems that in maintaining that all influence is immoral, one commits…

[Natural factors influencing sleep].

PubMed

Jurkowski, Marek K; Bobek-Billewicz, Barbara

2007-01-01

Sleep is a universal phenomenon of human and animal lives, although the importance of sleep for homeo-stasis is still unknown. Sleep disturbances influence many behavioral and physiologic processes, leading to health complications including death. On the other hand, sleep improvement can beneficially influence the course of healing of many disorders and can be a prognostic of health recovery. The factors influencing sleep have different biological and chemical origins. They are classical hormones, hypothalamic releasing and inhibitory hormones, neuropeptides, peptides and others as cytokines, prostaglandins, oleamid, adenosine, nitric oxide. These factors regulate most physiologic processes and are likely elements integrating sleep with physiology and physiology with sleep in health and disorders.

Collective Leadership: Principals' Decision Influence and the Supportive or Inhibiting Decision Influence of Other Stakeholders

ERIC Educational Resources Information Center

Ni, Yongmei; Yan, Rui; Pounder, Diana

2018-01-01

Purpose: Using the collective leadership framework, this study examines (a) how principals perceive their own influence and that of other key stakeholders in various school decisions and (b) how principals' perceived influences of other stakeholders are associated with their own influence. Research Method/Approach: This study uses the nationally…

Influence diagnostics in meta-regression model.

PubMed

Shi, Lei; Zuo, ShanShan; Yu, Dalei; Zhou, Xiaohua

2017-09-01

This paper studies the influence diagnostics in meta-regression model including case deletion diagnostic and local influence analysis. We derive the subset deletion formulae for the estimation of regression coefficient and heterogeneity variance and obtain the corresponding influence measures. The DerSimonian and Laird estimation and maximum likelihood estimation methods in meta-regression are considered, respectively, to derive the results. Internal and external residual and leverage measure are defined. The local influence analysis based on case-weights perturbation scheme, responses perturbation scheme, covariate perturbation scheme, and within-variance perturbation scheme are explored. We introduce a method by simultaneous perturbing responses, covariate, and within-variance to obtain the local influence measure, which has an advantage of capable to compare the influence magnitude of influential studies from different perturbations. An example is used to illustrate the proposed methodology. Copyright © 2017 John Wiley & Sons, Ltd.

Language may indeed influence thought.

PubMed

Zlatev, Jordan; Blomberg, Johan

2015-01-01

We discuss four interconnected issues that we believe have hindered investigations into how language may affect thinking. These have had a tendency to reappear in the debate concerning linguistic relativity over the past decades, despite numerous empirical findings. The first is the claim that it is impossible to disentangle language from thought, making the question concerning "influence" pointless. The second is the argument that it is impossible to disentangle language from culture in general, and from social interaction in particular, so it is impossible to attribute any differences in the thought patterns of the members of different cultures to language per se. The third issue is the objection that methodological and empirical problems defeat all but the most trivial version of the thesis of linguistic influence: that language gives new factual information. The fourth is the assumption that since language can potentially influence thought from "not at all" to "completely," the possible forms of linguistic influence can be placed on a cline, and competing theories can be seen as debating the actual position on this cline. We analyze these claims and show that the first three do not constitute in-principle objections against the validity of the project of investigating linguistic influence on thought, and that the last one is not the best way to frame the empirical challenges at hand. While we do not argue for any specific theory or mechanism for linguistic influence on thought, our discussion and the reviewed literature show that such influence is clearly possible, and hence in need of further investigations.

Social Influence on Risk Perception During Adolescence

PubMed Central

Magis-Weinberg, Lucía; Speekenbrink, Maarten; Blakemore, Sarah-Jayne

2015-01-01

Adolescence is a period of life in which peer relationships become increasingly important. Adolescents have a greater likelihood of taking risks when they are with peers rather than alone. In this study, we investigated the development of social influence on risk perception from late childhood through adulthood. Five hundred and sixty-three participants rated the riskiness of everyday situations and were then informed about the ratings of a social-influence group (teenagers or adults) before rating each situation again. All age groups showed a significant social-influence effect, changing their risk ratings in the direction of the provided ratings; this social-influence effect decreased with age. Most age groups adjusted their ratings more to conform to the ratings of the adult social-influence group than to the ratings of the teenager social-influence group. Only young adolescents were more strongly influenced by the teenager social-influence group than they were by the adult social-influence group, which suggests that to early adolescents, the opinions of other teenagers about risk matter more than the opinions of adults. PMID:25810453

Social influence on risk perception during adolescence.

PubMed

Knoll, Lisa J; Magis-Weinberg, Lucía; Speekenbrink, Maarten; Blakemore, Sarah-Jayne

2015-05-01

Adolescence is a period of life in which peer relationships become increasingly important. Adolescents have a greater likelihood of taking risks when they are with peers rather than alone. In this study, we investigated the development of social influence on risk perception from late childhood through adulthood. Five hundred and sixty-three participants rated the riskiness of everyday situations and were then informed about the ratings of a social-influence group (teenagers or adults) before rating each situation again. All age groups showed a significant social-influence effect, changing their risk ratings in the direction of the provided ratings; this social-influence effect decreased with age. Most age groups adjusted their ratings more to conform to the ratings of the adult social-influence group than to the ratings of the teenager social-influence group. Only young adolescents were more strongly influenced by the teenager social-influence group than they were by the adult social-influence group, which suggests that to early adolescents, the opinions of other teenagers about risk matter more than the opinions of adults. © The Author(s) 2015.

Culture and Influence in Multisite Evaluation

ERIC Educational Resources Information Center

Kirkhart, Karen E.

2011-01-01

Understanding the influence of multisite evaluation requires careful consideration of cultural context. The author illustrates dimensions of influence and culture with excerpts from four National Science Foundation evaluation case studies and summarizes what influence teaches everyone about culture and what culture teaches everyone about…

Measuring discursive influence across scholarship.

PubMed

Gerow, Aaron; Hu, Yuening; Boyd-Graber, Jordan; Blei, David M; Evans, James A

2018-03-27

Assessing scholarly influence is critical for understanding the collective system of scholarship and the history of academic inquiry. Influence is multifaceted, and citations reveal only part of it. Citation counts exhibit preferential attachment and follow a rigid "news cycle" that can miss sustained and indirect forms of influence. Building on dynamic topic models that track distributional shifts in discourse over time, we introduce a variant that incorporates features, such as authorship, affiliation, and publication venue, to assess how these contexts interact with content to shape future scholarship. We perform in-depth analyses on collections of physics research (500,000 abstracts; 102 years) and scholarship generally (JSTOR repository: 2 million full-text articles; 130 years). Our measure of document influence helps predict citations and shows how outcomes, such as winning a Nobel Prize or affiliation with a highly ranked institution, boost influence. Analysis of citations alongside discursive influence reveals that citations tend to credit authors who persist in their fields over time and discount credit for works that are influential over many topics or are "ahead of their time." In this way, our measures provide a way to acknowledge diverse contributions that take longer and travel farther to achieve scholarly appreciation, enabling us to correct citation biases and enhance sensitivity to the full spectrum of scholarly impact. Copyright © 2018 the Author(s). Published by PNAS.

Measuring discursive influence across scholarship

PubMed Central

Gerow, Aaron; Hu, Yuening; Boyd-Graber, Jordan; Blei, David M.

2018-01-01

Assessing scholarly influence is critical for understanding the collective system of scholarship and the history of academic inquiry. Influence is multifaceted, and citations reveal only part of it. Citation counts exhibit preferential attachment and follow a rigid “news cycle” that can miss sustained and indirect forms of influence. Building on dynamic topic models that track distributional shifts in discourse over time, we introduce a variant that incorporates features, such as authorship, affiliation, and publication venue, to assess how these contexts interact with content to shape future scholarship. We perform in-depth analyses on collections of physics research (500,000 abstracts; 102 years) and scholarship generally (JSTOR repository: 2 million full-text articles; 130 years). Our measure of document influence helps predict citations and shows how outcomes, such as winning a Nobel Prize or affiliation with a highly ranked institution, boost influence. Analysis of citations alongside discursive influence reveals that citations tend to credit authors who persist in their fields over time and discount credit for works that are influential over many topics or are “ahead of their time.” In this way, our measures provide a way to acknowledge diverse contributions that take longer and travel farther to achieve scholarly appreciation, enabling us to correct citation biases and enhance sensitivity to the full spectrum of scholarly impact. PMID:29531061

American Influence on Korean Education.

ERIC Educational Resources Information Center

Kim, Hyung-chan

1982-01-01

Discusses American influences on Korean education, considering the influence of American Protestant missionaries (1886-1945), relationship between American military government and Korean education, and educational cooperation between Korea and America since 1948. (JN)

Sibling influences on childhood development.

PubMed

Dunn, J

1988-03-01

To summarize the main points concerning sibling influence: 1. That siblings play a causal role in the development of aggressive behavior, in children's style of conflict behavior and in cooperative fantasy play is strongly suggested by recent research. 2. Marked problems in the sibling relationship are indicative of other problems, but a causal role for siblings is not established, other than for aggressive behavior. 3. Family factors are closely involved in the quality of sibling relationships--and thus in sibling influence, namely differential parental behavior, and the emotional climate of the family. That is, it is important not to consider the sibling relationship in isolation from other family relationships. 4. Studies of families under stress indicate heightened importance of these family factors. 5. It is likely, but not yet established, that later-born siblings are influenced by first-born in socio-cognitive development and gender identity. 6. Finally it should be noted that an important theme in current research on siblings is a concern with the question of why siblings develop to be so different from one another. It has been shown that the major source of environmental influence on the development of individual differences is within-family rather than between-family differences in experience (Plomin & Daniels, 1987). The different experiences each sibling may have within their relationship is one potential source of such differential environmental influence. Thus documenting the influence of siblings upon each other takes on added significance: By clarifying the extent and nature of this influence we will gain not only useful clinical information but illumination on a developmental principle of very general significance.

Emotional influences in patient safety.

PubMed

Croskerry, Pat; Abbass, Allan; Wu, Albert W

2010-12-01

The way that health care providers feel, both within themselves and toward their patients, may influence their clinical performance and impact patient safety, yet this aspect of provider behavior has received relatively little attention. How providers feel, their emotional or affective state, may exert a significant, unintended influence on their patients, and may compromise safety. We examined a broad literature across multiple disciplines to review the interrelationships between emotion, decision making, and behavior, and to assess their potential impact on patient safety. There is abundant evidence that the emotional state of the health care provider may be influenced by factors including characteristics of the patient, ambient conditions in the health care setting, diurnal, circadian, infradian, and seasonal variables, as well as endogenous disorders of the individual provider. These influences may lead to affective biases in decision making, resulting in errors and adverse events. Clinical reasoning and judgment may be particularly susceptible to emotional influence, especially those processes that rely on intuitive judgments. There are many ways that the emotional state of the health care provider can influence patient care. To reduce emotional errors, the level of awareness of these factors should be raised. Emotional skills training should be incorporated into the education of health care professionals. Specifically, clinical teaching should promote more openness and discussion about the provider's feelings toward patients. Strategies should be developed to help providers identify and de-bias themselves against emotional influences that may impact care, particularly in the emotionally evocative patient. Psychiatric conditions within the provider, which may compromise patient safety, need to be promptly detected, diagnosed, and managed.

Influence: A Key to Successful Leadership

ERIC Educational Resources Information Center

Hoy, Wayne K.; Smith, Page A.

2007-01-01

Purpose: The purpose of this article is to examine and condense the literature on influence and persuasion. Design/methodology/approach: The article identifies basic principles of influence in the theoretical and research literature, which are supported by empirical study. Findings: Ten principles of influence were identified, empirical support…

Nurses' policy influence: A concept analysis.

PubMed

Arabi, Akram; Rafii, Forough; Cheraghi, Mohammad Ali; Ghiyasvandian, Shahrzad

2014-05-01

Nurses' influence on health policy protects the quality of care by access to required recourses and opportunities. This is a new and important concept for nursing; however, research studies on policy influence of nurses in health care sector are lacking a basic conceptual understanding of what this concept represents. The aim of this paper is to clarify the concept of nurses' policy influence and to propose the definition of this concept, considering the context of Iran. The eight stages of Walker and Avant approach was used to guide this concept analysis. Various databases and internet engines were searched to find all related information about the concept. Textbooks were also searched manually. English language literature reports published between 1990 and 2012 were reviewed. Based on the analysis undertaken, nurses' policy influence is nurses' ability in influencing decisions and affairs related to health through political knowledge, effective communication, and collaboration with other members of the health team, which results in the improvement of nurses' job environment and increases patient outcomes. This is a dynamic process situated on a spectrum and is accompanied with nurses' knowledge, competency, power, and advocacy, and also their ability to change. Nurses have individual views on health care issues and influence health care policies in different ways. With a common understanding of nurses' policy influence as a concept, nurses will recognize the importance of policy making in the health sector and their influence on this process and also on patients' outcomes.

Interpersonal Influence Styles of Adult Cohorts.

ERIC Educational Resources Information Center

Hoffman, Stephanie B.

Generational differences in the balance of power contribute to varying patterns of influence strategy use within cohorts of young, middle-aged, and older adults. The self-report Likelihood of Influence Tactic Use Scale was administered to 10 males and 10 females in each of three cohort groups to investigate the influence tactics used at different…

Positive and Negative Peer Influence in Residential Care.

PubMed

Huefner, Jonathan C; Smith, Gail L; Stevens, Amy L

2017-10-13

The potential for negative peer influence has been well established in research, and there is a growing interest in how positive peer influence also impacts youth. No research, however, has concurrently examined positive and negative peer influence in the context of residential care. Clinical records for 886 residential care youth were used in a Hierarchical Linear Model analysis to examine the impact of negative and positive peer influence on naturally occurring patterns of serious problem behavior over time. Negative peer influence, where the majority of youth in a home manifested above the average number of serious behavior problems, occurred 13.7% of the time. Positive peer influence, where the majority of youth manifested no serious problem behaviors for the month, occurred 47.7% of the time. Overall, youth problem behavior improved over time. There were significantly lower rates of serious problem behavior in target youth during positive peer influence months. Conversely, there were significantly higher rates of serious problem behaviors in target youth during negative peer influence months. Negative peer influence had a relatively greater impact on target peers' serious behavior problems than did positive peer influence. Caregiver experience significantly reduced the impact of negative peer influence, but did not significantly augment positive peer influence. Months where negative peer influence was combined with inexperienced caregivers produced the highest rates of serious problem behavior. Our results support the view that residential programs for troubled youth need to create circumstances that promote positive and control for negative peer influence.

Lineup administrator influences on eyewitness identification decisions.

PubMed

Clark, Steven E; Marshall, Tanya E; Rosenthal, Robert

2009-03-01

The present research examines how a lineup administrator may influence eyewitness identification decisions through different forms of influence, after providing the witness with standard, unbiased instructions. Participant-witnesses viewed a staged crime and were later shown a target-present or target-absent lineup. The lineup administrators either remained silent while the witness examined the lineup, made ostensibly cautionary statements to the witness, or prompted the witness to identify the person in the lineup who seemed most similar to the perpetrator. These two forms of influence, denoted as subtle-influence and similarity-influence conditions, led to different patterns of identification results. Results for the similarity-influence condition were generally consistent with criterion shift and relative judgment models of eyewitness decision making. Results for the subtle-influence condition, however, cannot be explained by alterations in the decision rule. A weighted matching model is outlined to explain results from the subtle-influence condition. Witnesses seemed generally unaware of the attempts by the lineup administrator to influence their decision, although some noted it, and the probative value of suspect identifications was lower for those who did note it. Implications for theory and policy are discussed. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Students' Dependence on Smart Phones: The Influence of Social Needs, Social Influences and Convenience

ERIC Educational Resources Information Center

Suki, Norazah Mohd

2013-01-01

Purpose: The purpose of this paper is to assess whether social needs, social influences and convenience of smart phones affects students' dependence on them. This research also examines whether students' dependence on smart phones influences their purchase behaviour. This investigation is conducted among the students in a public university in the…

Wetland Research Can Influence Policy

EPA Science Inventory

An objective of ecological research is to have a positive influence on the way natural resources are managed. The ability to influence policy with science depends on collaboration with the appropriate audience, identification of a relevant question, and awareness of the framewor...

Language may indeed influence thought

PubMed Central

Zlatev, Jordan; Blomberg, Johan

2015-01-01

We discuss four interconnected issues that we believe have hindered investigations into how language may affect thinking. These have had a tendency to reappear in the debate concerning linguistic relativity over the past decades, despite numerous empirical findings. The first is the claim that it is impossible to disentangle language from thought, making the question concerning “influence” pointless. The second is the argument that it is impossible to disentangle language from culture in general, and from social interaction in particular, so it is impossible to attribute any differences in the thought patterns of the members of different cultures to language per se. The third issue is the objection that methodological and empirical problems defeat all but the most trivial version of the thesis of linguistic influence: that language gives new factual information. The fourth is the assumption that since language can potentially influence thought from “not at all” to “completely,” the possible forms of linguistic influence can be placed on a cline, and competing theories can be seen as debating the actual position on this cline. We analyze these claims and show that the first three do not constitute in-principle objections against the validity of the project of investigating linguistic influence on thought, and that the last one is not the best way to frame the empirical challenges at hand. While we do not argue for any specific theory or mechanism for linguistic influence on thought, our discussion and the reviewed literature show that such influence is clearly possible, and hence in need of further investigations. PMID:26582997

Bounded-Influence Inference in Regression.

DTIC Science & Technology

1984-02-01

be viewed as generalization of the classical F-test. By means of the influence function their robustness properties are investigated and optimally...robust tests that maximize the asymptotic power within each class, under the side condition of a bounded influence function , are constructed. Finally, an

Normative social influence is underdetected.

PubMed

Nolan, Jessica M; Schultz, P Wesley; Cialdini, Robert B; Goldstein, Noah J; Griskevicius, Vladas

2008-07-01

The present research investigated the persuasive impact and detectability of normative social influence. The first study surveyed 810 Californians about energy conservation and found that descriptive normative beliefs were more predictive of behavior than were other relevant beliefs, even though respondents rated such norms as least important in their conservation decisions. Study 2, a field experiment, showed that normative social influence produced the greatest change in behavior compared to information highlighting other reasons to conserve, even though respondents rated the normative information as least motivating. Results show that normative messages can be a powerful lever of persuasion but that their influence is underdetected.

The Influence of law on Strategy

DTIC Science & Technology

2016-05-26

Approved for public release; distribution is unlimited The Influence of Law on Strategy A Monograph by Kevin G. Rousseau School of Advanced...2016 4. TITLE AND SUBTITLE The Influence of Law on Strategy 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...NOTES 14. ABSTRACT Strategists must understand the legal dynamics that are exerting an increasingly powerful influence on the legitimate use of

One angry woman: Anger expression increases influence for men, but decreases influence for women, during group deliberation.

PubMed

Salerno, Jessica M; Peter-Hagene, Liana C

2015-12-01

We investigated whether expressing anger increases social influence for men, but diminishes social influence for women, during group deliberation. In a deception paradigm, participants believed they were engaged in a computer-mediated mock jury deliberation about a murder case. In actuality, the interaction was scripted. The script included 5 other mock jurors who provided verdicts and comments in support of the verdicts; 4 agreed with the participant and 1 was a "holdout" dissenter. Holdouts expressed their opinions with no emotion, anger, or fear and had either male or female names. Holdouts exerted no influence on participants' opinions when they expressed no emotion or fear. Participants' confidence in their own verdict dropped significantly, however, after male holdouts expressed anger. Yet, anger expression undermined female holdouts: Participants became significantly more confident in their original verdicts after female holdouts expressed anger-even though they were expressing the exact same opinion and emotion as the male holdouts. Mediation analyses revealed that participants drew different inferences from male versus female anger, which created a gender gap in influence during group deliberation. The current study has implications for group decisions in general, and jury deliberations in particular, by suggesting that expressing anger might lead men to gain influence, but women to lose influence over others (even when making identical arguments). These diverging consequences might result in women potentially having less influence on societally important decisions than men, such as jury verdicts. (c) 2015 APA, all rights reserved).

Lunar Influences on Human Aggression.

ERIC Educational Resources Information Center

Russell, Gordon W.; Dua, Manjula

1983-01-01

Used league records of all Canadian hockey games (N=426) played during a season to test a lunar-aggression hypothesis. Despite the use of multiple measures of lunar phase and interpersonal aggression, support for lunar influence was not forthcoming. Supplemental data revealed that beliefs in lunar influence are fairly common. (JAC)

Conceptual Dimensions of Interpersonal Influence.

ERIC Educational Resources Information Center

McCallum, Debra Moehle; And Others

Interpersonal power has been defined as the ability of an agent to alter the behavior of a target through means-control, attractiveness, and credibility. To identify and delineate situations of influence in personal relationships, undergraduate students either wrote influence descriptions (N=96), made similarity judgments on the original 96…

Text Signals Influence Team Artifacts

ERIC Educational Resources Information Center

Clariana, Roy B.; Rysavy, Monica D.; Taricani, Ellen

2015-01-01

This exploratory quasi-experimental investigation describes the influence of text signals on team visual map artifacts. In two course sections, four-member teams were given one of two print-based text passage versions on the course-related topic "Social influence in groups" downloaded from Wikipedia; this text had two paragraphs, each…

Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the Yuma Valley, Arizona, 1995

USGS Publications Warehouse

Tadayon, Saeid; King, K.A.; Andrews, Brenda; Roberts, William

1997-01-01

, and concentrations ranged from 11 to 16 micrograms per gram. Concentrations ofaluminum, beryllium, boron, copper, lead, and zinc were highest in samples from Main Drain at southerly international boundary near San Luis, Arizona. Selenium was detected in all bottom-sediment samples, and concentrations ranged from 0.1 to 0.7 micrograms per gram. Concentrations of cadmium, europium, homium, mercury, molybdenum, silver, tantalum, tin, and uranium were below analytical reporting limits in the bottom-sediment samples. Concentrations of trace elements in bottom-sediment samples were within the ranges found in a study of soils of the western United States and did not indicate a significant accumulation of these constituents. p,p'Dichlorodiphenyldichloroethylene (commonly referred to as p,-p'-DDE) was detected in one bottom-sediment sample at a concentration of 1.4 micrograms per gram. No other organochlorine compounds were detected in the bottom-sediment samples. DDE was present in all fish and bird samples. Almost one-half of the fish samples contained DDE residues that were two times higher than the mean calculated for a national study in 1984-85. Twenty-tree percent of the fish contained more than three times the national mean. Fish from downstream parts of the Main Drain had the highest concentrations of DDE. Although concentrations of DDE in fish and in bird carcasses and eggs were above background levels, residues generally were below thresholds associated with chronic poisoning and reproductive problems in figh and wildlife. Concentrations of 18 trace elements were detected in cattail (Typha sp.) roots, freshwater clam (Corbicula fluminea), fish, and bird samples. Selenium in most fish and in livers of red-winged (Agelaius phoeniceus) and yellow-headed (Xanthocephalus xanthocephalus) blackbirds was above background concentrations but below toxic concentrations. In contrast, selenium was present in a killdeer (Charadrium vociferus) liver sample at potentially toxic con

Real-time topic-aware influence maximization using preprocessing.

PubMed

Chen, Wei; Lin, Tian; Yang, Cheng

2016-01-01

Influence maximization is the task of finding a set of seed nodes in a social network such that the influence spread of these seed nodes based on certain influence diffusion model is maximized. Topic-aware influence diffusion models have been recently proposed to address the issue that influence between a pair of users are often topic-dependent and information, ideas, innovations etc. being propagated in networks are typically mixtures of topics. In this paper, we focus on the topic-aware influence maximization task. In particular, we study preprocessing methods to avoid redoing influence maximization for each mixture from scratch. We explore two preprocessing algorithms with theoretical justifications. Our empirical results on data obtained in a couple of existing studies demonstrate that one of our algorithms stands out as a strong candidate providing microsecond online response time and competitive influence spread, with reasonable preprocessing effort.

Influencing Safety in Australian Agriculture and Fisheries.

PubMed

McBain-Rigg, Kristin E; Franklin, Richard C; King, Jemma C; Lower, Tony

2017-01-01

Improving the health and safety of those working in Australian agriculture and fishery industries is a recognized priority area for preventative activities. With Australian agricultural industries being among the nation's most dangerous workplaces, there is a need for action. While there are currently known solutions, their implementation is limited. Influential agents, i.e., people who can influence others, are important for helping engender action to enact solutions into practice. This study examines agents that influence safety behavior either negatively (barriers) or positively (facilitators), in the Australian agriculture and fishery industries. Focus groups were conducted with producers and industry representatives. Thematic analysis identified barriers and facilitators to improve health and safety. These were assessed against the Socioecological Model, which considers the various, and often intersecting, human (intrapersonal, i.e. values and attitudes, peers, familial, and cultural) factors influencing safety behavior. Seven categories of human influences were identified: self, peers, family, intergenerational change, industry agents, government agents, and other. Peers (including direct managers) and family were seen to be direct influencers. Individuals signal to others that safety is valued and important. This is reinforced by experience, skill, attitudes, and behavior. Safety practice knowledge acquisition occurred via the family unit, specific training, industry, or knowledge transfer between industries. Government influence predominately focused on legislation and while the source of this influence is distant, it does influence behavior. There is a need to support comprehensive programs. These should include strengthening relationships via peer-to-peer networking, sharing information about safety initiatives, appropriate legislation, and enhancing leadership of all influencers with regard to safety.

Modified Gaussian influence function of deformable mirror actuators.

PubMed

Huang, Linhai; Rao, Changhui; Jiang, Wenhan

2008-01-07

A new deformable mirror influence function based on a Gaussian function is introduced to analyze the fitting capability of a deformable mirror. The modified expressions for both azimuthal and radial directions are presented based on the analysis of the residual error between a measured influence function and a Gaussian influence function. With a simplex search method, we further compare the fitting capability of our proposed influence function to fit the data produced by a Zygo interferometer with that of a Gaussian influence function. The result indicates that the modified Gaussian influence function provides much better performance in data fitting.

The proven, often unconscious, influence of small gifts.

PubMed

2011-12-01

Many studies have shown that even small gifts influence the recipient. Gifts work as a marketing tool by exploiting psychological and social responses that have been well described by the social sciences. Social science explains why, counterintuitively, a small gift has the potential to influence the recipient more than a large one, specifically because the recipient is unaware of its influence. Exposure to promotional items (pens, logos) also influences attitudes. Understanding marketing techniques and their psychological basis helps us resist being influenced. The regulations in force do not take sufficient account of the potential of corporate gifts to influence healthcare professionals.

Brain Substrates of Recovery from Misleading Influence

PubMed Central

Dudai, Yadin; Dolan, Raymond J.; Sharot, Tali

2014-01-01

Humans are strongly influenced by their environment, a dependence that can lead to errors in judgment. Although a rich literature describes how people are influenced by others, little is known regarding the factors that predict subsequent rectification of misleading influence. Using a mediation model in combination with brain imaging, we propose a model for the correction of misinformation. Specifically, our data suggest that amygdala modulation of hippocampal mnemonic representations, during the time of misleading social influence, is associated with reduced subsequent anterior–lateral prefrontal cortex activity that reflects correction. These findings illuminate the process by which erroneous beliefs are, or fail to be, rectified and highlight how past influence constrains subsequent correction. PMID:24899698

Age differences in the prosocial influence effect.

PubMed

Foulkes, Lucy; Leung, Jovita T; Fuhrmann, Delia; Knoll, Lisa J; Blakemore, Sarah-Jayne

2018-04-15

Social influence occurs when an individual's thoughts or behaviours are affected by other people. There are significant age effects on susceptibility to social influence, typically a decline from childhood to adulthood. Most research has focused on negative aspects of social influence, such as peer influence on risky behaviour, particularly in adolescence. The current study investigated the impact of social influence on the reporting of prosocial behaviour (any act intended to help another person). In this study, 755 participants aged 8-59 completed a computerized task in which they rated how likely they would be to engage in a prosocial behaviour. Afterwards, they were told the average rating (in fact fictitious) that other participants had given to the same question, and then were asked to rate the same behaviour again. We found that participants' age affected the extent to which they were influenced by other people: children (8-11 years), young adolescents (12-14 years) and mid-adolescents (15-18 years) all significantly changed their ratings, while young adults (19-25 years) and adults (26-59 years) did not. Across the three youngest age groups, children showed the most susceptibility to prosocial influence, changing their reporting of prosocial behaviour the most. The study provides evidence that younger people's increased susceptibility to social influence can have positive outcomes. © 2018 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

Interdependent Sampling and Social Influence

ERIC Educational Resources Information Center

Denrell, Jerker; Le Mens, Gael

2007-01-01

Most explanations of social influence focus on why individuals might want to agree with the opinions or attitudes of others. The authors propose a different explanation that assumes the attitudes of others influence only the activities and objects individuals are exposed to. For example, individuals are likely to be exposed to activities that…

For Fit's Sake: A Norms-Based Approach to Healthy Behaviors Through Influence of Presumed Media Influence.

PubMed

Ho, Shirley S; Lee, Edmund W J; Ng, Kaijie; Leong, Grace S H; Tham, Tiffany H M

2016-09-01

Based on the influence of presumed media influence (IPMI) model as the theoretical framework, this study examines how injunctive norms and personal norms mediate the influence of healthy lifestyle media messages on public intentions to engage in two types of healthy lifestyle behaviors-physical activity and healthy diet. Nationally representative data collected from 1,055 adults in Singapore demonstrate partial support for the key hypotheses that make up the extended IPMI model, highlighting the importance of a norms-based approach in health communication. Our results indicate that perceived media influence on others indirectly shaped public intentions to engage in healthy lifestyle behaviors through personal norms and attitude, providing partial theoretical support for the extended IPMI model. Practical implications for health communicators in designing health campaigns media messages to motivate the public to engage in healthy lifestyle are discussed.

A Study of Upward Influence in Organizations.

ERIC Educational Resources Information Center

Schilit, Warren K.; Locke, Edwin A.

1982-01-01

Researchers interviewed 83 subordinate employees and 70 supervisory employees to investigate the ways subordinates try to influence their supervisors. Supervisors and subordinates reported similar agents and methods of influence, causes of success, and outcomes of attempts at upward influence, but different causes of failure. (Author/RW)

Neural mechanisms of social influence in adolescence

PubMed Central

Welborn, B. Locke; Lieberman, Matthew D.; Goldenberg, Diane; Fuligni, Andrew J.; Galván, Adriana

2016-01-01

During the transformative period of adolescence, social influence plays a prominent role in shaping young people’s emerging social identities, and can impact their propensity to engage in prosocial or risky behaviors. In this study, we examine the neural correlates of social influence from both parents and peers, two important sources of influence. Nineteen adolescents (age 16–18 years) completed a social influence task during a functional magnetic resonance imaging (fMRI) scan. Social influence from both sources evoked activity in brain regions implicated in mentalizing (medial prefrontal cortex, left temporoparietal junction, right temporoparietal junction), reward (ventromedial prefrontal cortex), and self-control (right ventrolateral prefrontal cortex). These results suggest that mental state reasoning, social reward and self-control processes may help adolescents to evaluate others’ perspectives and overcome the prepotent force of their own antecedent attitudes to shift their attitudes toward those of others. Findings suggest common neural networks involved in social influence from both parents and peers. PMID:26203050

[Extraterrestrial influences on health and disease].

PubMed

Sitar, J

1994-02-14

As to extraterrestrial influences on man in health and disease so far only the effect of the sun and moon are known. This concerns the effect of solar radiation of different wavelengths and the effect of corpuscular solar radiation which has an impact on the condition of the terrestrial magnetic field and electric conditions in the atmosphere. Moreover there is also a question of important influences of gravitation (tides). Here the influence of the position of the moon in relation to the connecting line between sun and earth is involved. In the course of the synodic month (from new moon to the next new moon) a semilunar periodicity of different medical and geomagnetic indicators as well as meteorological ones plays a part. Based on his own research and that of others the author reaches the conclusion that extraterrestrial and terrestrial influences are interrelated and exert a mutual influence on each other and that it is not sensible to separate them strictly. Investigation of all the mentioned influences is important not only for biomedical prognosis but also for basic geophysical and meteorological research. Perspectively it would be useful to plan model experiments. The author feels it is his duty to refuse publication of different horoscopes in the mass media, whatever the intention. In the lay public this may lead to popularization of astrology which has nothing in common with serious research.

Family Structure and Social Influence.

ERIC Educational Resources Information Center

Olson, Dawn R.

Regardless of family form, there is a universal belief that one's family is the most powerful agent of socialization. A sample of 38 junior high school students from single parent and nuclear families completed a questionnaire in order to examine the relative effects of peer influence and family influence in single parent and nuclear families.…

Thinking aloud influences perceived time.

PubMed

Hertzum, Morten; Holmegaard, Kristin Due

2015-02-01

We investigate whether thinking aloud influences perceived time. Thinking aloud is widely used in usability evaluation, yet it is debated whether thinking aloud influences thought and behavior. If thinking aloud is restricted to the verbalization of information to which a person is already attending, there is evidence that thinking aloud does not influence thought and behavior. In an experiment, 16 thinking-aloud participants and 16 control participants solved a code-breaking task 24 times each. Participants estimated task duration. The 24 trials involved two levels of time constraint (timed, untimed) and resulted in two levels of success (solved, unsolved). The ratio of perceived time to clock time was lower for thinking-aloud than control participants. Participants overestimated time by an average of 47% (thinking aloud) and 94% (control). The effect of thinking aloud on time perception also held separately for timed, untimed, solved, and unsolved trials. Thinking aloud (verbalization at Levels 1 and 2) influences perceived time. Possible explanations of this effect include that thinking aloud may require attention, cause a processing shift that overshadows the perception of time, or increase mental workload. For usability evaluation, this study implies that time estimates made while thinking aloud cannot be compared with time estimates made while not thinking aloud, that ratings of systems experienced while thinking aloud may be inaccurate (because the experience of time influences other experiences), and that it may therefore be considered to replace concurrent thinking aloud with retrospective thinking aloud when evaluations involve time estimation.

17 CFR 200.61 - Impressions of influence.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Impressions of influence. 200...; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Canons of Ethics § 200.61 Impressions of influence. A... influence him, that any person unduly enjoys his favor or that he is affected in any way by the rank...

Neural mechanisms of social influence in adolescence.

PubMed

Welborn, B Locke; Lieberman, Matthew D; Goldenberg, Diane; Fuligni, Andrew J; Galván, Adriana; Telzer, Eva H

2016-01-01

During the transformative period of adolescence, social influence plays a prominent role in shaping young people's emerging social identities, and can impact their propensity to engage in prosocial or risky behaviors. In this study, we examine the neural correlates of social influence from both parents and peers, two important sources of influence. Nineteen adolescents (age 16-18 years) completed a social influence task during a functional magnetic resonance imaging (fMRI) scan. Social influence from both sources evoked activity in brain regions implicated in mentalizing (medial prefrontal cortex, left temporoparietal junction, right temporoparietal junction), reward (ventromedial prefrontal cortex), and self-control (right ventrolateral prefrontal cortex). These results suggest that mental state reasoning, social reward and self-control processes may help adolescents to evaluate others' perspectives and overcome the prepotent force of their own antecedent attitudes to shift their attitudes toward those of others. Findings suggest common neural networks involved in social influence from both parents and peers. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Collective Influence Algorithm to find influencers via optimal percolation in massively large social media

NASA Astrophysics Data System (ADS)

Morone, Flaviano; Min, Byungjoon; Bo, Lin; Mari, Romain; Makse, Hernán A.

2016-07-01

We elaborate on a linear-time implementation of Collective-Influence (CI) algorithm introduced by Morone, Makse, Nature 524, 65 (2015) to find the minimal set of influencers in networks via optimal percolation. The computational complexity of CI is O(N log N) when removing nodes one-by-one, made possible through an appropriate data structure to process CI. We introduce two Belief-Propagation (BP) variants of CI that consider global optimization via message-passing: CI propagation (CIP) and Collective-Immunization-Belief-Propagation algorithm (CIBP) based on optimal immunization. Both identify a slightly smaller fraction of influencers than CI and, remarkably, reproduce the exact analytical optimal percolation threshold obtained in Random Struct. Alg. 21, 397 (2002) for cubic random regular graphs, leaving little room for improvement for random graphs. However, the small augmented performance comes at the expense of increasing running time to O(N2), rendering BP prohibitive for modern-day big-data. For instance, for big-data social networks of 200 million users (e.g., Twitter users sending 500 million tweets/day), CI finds influencers in 2.5 hours on a single CPU, while all BP algorithms (CIP, CIBP and BDP) would take more than 3,000 years to accomplish the same task.

Collective Influence Algorithm to find influencers via optimal percolation in massively large social media.

PubMed

Morone, Flaviano; Min, Byungjoon; Bo, Lin; Mari, Romain; Makse, Hernán A

2016-07-26

We elaborate on a linear-time implementation of Collective-Influence (CI) algorithm introduced by Morone, Makse, Nature 524, 65 (2015) to find the minimal set of influencers in networks via optimal percolation. The computational complexity of CI is O(N log N) when removing nodes one-by-one, made possible through an appropriate data structure to process CI. We introduce two Belief-Propagation (BP) variants of CI that consider global optimization via message-passing: CI propagation (CIP) and Collective-Immunization-Belief-Propagation algorithm (CIBP) based on optimal immunization. Both identify a slightly smaller fraction of influencers than CI and, remarkably, reproduce the exact analytical optimal percolation threshold obtained in Random Struct. Alg. 21, 397 (2002) for cubic random regular graphs, leaving little room for improvement for random graphs. However, the small augmented performance comes at the expense of increasing running time to O(N(2)), rendering BP prohibitive for modern-day big-data. For instance, for big-data social networks of 200 million users (e.g., Twitter users sending 500 million tweets/day), CI finds influencers in 2.5 hours on a single CPU, while all BP algorithms (CIP, CIBP and BDP) would take more than 3,000 years to accomplish the same task.

Collective Influence Algorithm to find influencers via optimal percolation in massively large social media

PubMed Central

Morone, Flaviano; Min, Byungjoon; Bo, Lin; Mari, Romain; Makse, Hernán A.

2016-01-01

We elaborate on a linear-time implementation of Collective-Influence (CI) algorithm introduced by Morone, Makse, Nature 524, 65 (2015) to find the minimal set of influencers in networks via optimal percolation. The computational complexity of CI is O(N log N) when removing nodes one-by-one, made possible through an appropriate data structure to process CI. We introduce two Belief-Propagation (BP) variants of CI that consider global optimization via message-passing: CI propagation (CIP) and Collective-Immunization-Belief-Propagation algorithm (CIBP) based on optimal immunization. Both identify a slightly smaller fraction of influencers than CI and, remarkably, reproduce the exact analytical optimal percolation threshold obtained in Random Struct. Alg. 21, 397 (2002) for cubic random regular graphs, leaving little room for improvement for random graphs. However, the small augmented performance comes at the expense of increasing running time to O(N2), rendering BP prohibitive for modern-day big-data. For instance, for big-data social networks of 200 million users (e.g., Twitter users sending 500 million tweets/day), CI finds influencers in 2.5 hours on a single CPU, while all BP algorithms (CIP, CIBP and BDP) would take more than 3,000 years to accomplish the same task. PMID:27455878

Understanding the antecedents of Korean high school students' drinking refusal self-efficacy: parental influence, peer influence, and behavior.

PubMed

Jang, Su Ahn; Cho, Namauk; Yoo, Jina

2011-12-29

The current study examined the factors that influence Korean adolescents' drinking refusal self-efficacy, which is known to be associated with alcohol use and drinking intentions. Specifically, this study considered parental monitoring, parent-child communication satisfaction, peer influence, and prior alcohol use as possible antecedents of Korean high school students' drinking refusal self-efficacy. High school students (n = 538) in South Korea responded to the current study. The data revealed that parent-child communication satisfaction facilitated parental monitoring, and these factors indirectly predicted adolescents' drinking behavior through peer influence. We also found that prior drinking, parental monitoring, and peer influence were directly associated with drinking refusal self-efficacy, and the self-efficacy, in turn, was associated with drinking intentions. These results not only suggest that drinking refusal self-efficacy are related to drinking behavior and intentions, but they also provide a theoretical explanation for how parental and peer influences are associated with adolescents' drinking refusal self-efficacy.

Understanding the Antecedents of Korean High School Students’ Drinking Refusal Self-Efficacy: Parental Influence, Peer Influence, and Behavior

PubMed Central

Jang, Su Ahn; Cho, NamAuk; Yoo, Jina

2012-01-01

The current study examined the factors that influence Korean adolescents’ drinking refusal self-efficacy, which is known to be associated with alcohol use and drinking intentions. Specifically, this study considered parental monitoring, parent-child communication satisfaction, peer influence, and prior alcohol use as possible antecedents of Korean high school students’ drinking refusal self-efficacy. High school students (n = 538) in South Korea responded to the current study. The data revealed that parent-child communication satisfaction facilitated parental monitoring, and these factors indirectly predicted adolescents’ drinking behavior through peer influence. We also found that prior drinking, parental monitoring, and peer influence were directly associated with drinking refusal self-efficacy, and the self-efficacy, in turn, was associated with drinking intentions. These results not only suggest that drinking refusal self-efficacy are related to drinking behavior and intentions, but they also provide a theoretical explanation for how parental and peer influences are associated with adolescents’ drinking refusal self-efficacy. PMID:22980099

Influence of convection on microstructure

NASA Technical Reports Server (NTRS)

Wilcox, William R.; Caram, Rubens; Mohanty, A. P.; Seth, Jayshree

1990-01-01

The mechanism responsible for the difference in microstructure caused by solidifying the MnBi-Bi eutectic in space is sought. The objectives for the three year period are as follows: (1) completion of the following theoretical analyses - determination of the influence of the Soret effect on the average solid composition versus distance of off-eutectic mixtures directionally solidified in the absence of convection, determination of the influence of convection on the microstructure of off-eutectic mixtures using a linear velocity profile in the adjacent melt, determination of the influence of volumetric changes during solidification on microconvection near the freezing interface and on microstructure, and determination of the influence of convection on microstructure when the MnBi fibers project out in front of the bismuth matrix; (2) search for patterns in the effect of microgravity on different eutectics (for example, eutectic composition, eutectic temperature, usual microstructure, densities of pure constituents, and density changes upon solidification); and (3) determination of the Soret coefficient and the diffusion coefficient for Mn-Bi melts near the eutectic composition, both through laboratory experiements to be performed here and from data from Shuttle experiments.

Factors influencing children's food choice.

PubMed

Koivisto Hursti, U K

1999-04-01

Although food habits are not stable and unchanging during a person's lifetime, a base for healthy food habits can be created in early childhood. Children's food habits can be assumed to be influenced by their parents' food habits and choices. The aim of this article is to review factors influencing food choice in children as well as in adults. The results demonstrate that the development of children's food habits is influenced by a multitude of factors. Parents play an important role in the formation of food habits and preferences of young children. They can influence their children's food choice by making specific foods available, by acting as models for their children and by their behaviour in specific situations. Children tend to be afraid of new foods and do not readily accept them. However, experience is known to enhance preference, and earlier experiences of a particular food are the major determinants of the development of children's food acceptance patterns. Thus, parents should be encouraged to make healthy foods easily available to the child and serve these foods in positive mealtime situations in order to help their child to develop healthy food habits.

Factors influencing children's food choice.

PubMed

Hursti, Ulla-Kaisa Koivisto

1999-01-01

Although food habits arc not stable and unchanging during a person's lifetime, a base for healthy food habits can be created in early childhood. Children's food habits can be assumed to be influenced by their parents' food habits and choices. The aim of this article is to review factors influencing food choice in children as well as in adults. The results demonstrate that the development of children's food habits is influenced by a multitude of factors. Parents play an important role in the formation of food habits and preferences of young children. They can influence their children's food choice by making specific foods available, by acting as models for their children and by their behaviour in specific situations. Children tend to be afraid of new foods and do not readily accept them. However, experience is known to enhance preference, and earlier experiences of a particular food are the major determinants of the development of children's food acceptance patterns. Thus, parents should be encouraged to make healthy foods easily available to the child and serve these foods in positive mealtime situations in order to help their child to develop healthy food habits.

Influence analysis in quantitative trait loci detection.

PubMed

Dou, Xiaoling; Kuriki, Satoshi; Maeno, Akiteru; Takada, Toyoyuki; Shiroishi, Toshihiko

2014-07-01

This paper presents systematic methods for the detection of influential individuals that affect the log odds (LOD) score curve. We derive general formulas of influence functions for profile likelihoods and introduce them into two standard quantitative trait locus detection methods-the interval mapping method and single marker analysis. Besides influence analysis on specific LOD scores, we also develop influence analysis methods on the shape of the LOD score curves. A simulation-based method is proposed to assess the significance of the influence of the individuals. These methods are shown useful in the influence analysis of a real dataset of an experimental population from an F2 mouse cross. By receiver operating characteristic analysis, we confirm that the proposed methods show better performance than existing diagnostics. © 2014 The Author. Biometrical Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Factors influencing twins and zygosity.

PubMed

Hankins, Gary V D; Saade, George R

2005-01-01

Zygosity is influenced by many factors. Monozygotic twins occur spontaneously in approximately 1 in 250 births and are felt to increase twofold with ovulation induction techniques. Monozygotic twinning also increases in proportion to the number of blastocysts transferred during in vitro fertilisation. In contrast, dizygotic twinning appears to be influenced by race, genetic factors, maternal age, fertility enhancing drugs, folic acid supplementation, and maternal nutritional status.

How Sex and Gender Influence Health and Disease

MedlinePlus

... a Biological Variable (SABV) Questions & Answers Sex & Gender Sex & Gender Sex/gender influence health and disease, and ... How Sex/Gender Influence Health & Disease Infographic: How Sex/Gender Influence Health & Disease Enlarge Infographic (PDF - 558KB) ...

Do romantic partners influence each other's heavy episodic drinking? Support for the partner influence hypothesis in a three-year longitudinal study.

PubMed

Bartel, Sara J; Sherry, Simon B; Molnar, Danielle S; Mushquash, Aislin R; Leonard, Kenneth E; Flett, Gordon L; Stewart, Sherry H

2017-06-01

Approximately one in five adults engage in heavy episodic drinking (HED), a behavior with serious health and social consequences. Environmental, intrapersonal, and interpersonal factors contribute to and perpetuate HED. Prior research supports the partner influence hypothesis where partners influence each other's HED. We examined the partner influence hypothesis longitudinally over three years in heterosexual couples in serious romantic relationships, while exploring possible sex differences in the magnitude of partner influence. One-hundred-and-seventy-nine heterosexual couples in serious relationships (38.5% married at baseline) completed a measure of HED at baseline and again three years later. Using actor-partner interdependence modelling, results showed actor effects for both men and women, with HED remaining stable for each partner from baseline to follow-up. Significant partner effects were found for both men and women, who both positively influenced their partners' HED over the three-year follow-up. The partner influence hypothesis was supported. Results indicated partner influences on HED occur over the longer term and apply to partners in varying stages of serious romantic relationships (e.g., cohabiting, engaged, married). Women were found to influence their partners' HED just as much as men influence their partners' HED. Findings suggest HED should be assessed and treated as a couples' issue rather than simply as an individual risky behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cooperative networks overcoming defectors by social influence

NASA Astrophysics Data System (ADS)

Gomez Portillo, Ignacio

2014-01-01

We address the cooperation problem in structured populations by considering the prisoner’s dilemma game as a metaphor of the social interactions between individuals with imitation capacity. We present a new strategy update rule called democratic weighted update where the individual’s behavior is socially influenced by each one of their neighbors. In particular, the capacity of an individual to socially influence other ones is proportional to its accumulated payoff. When in a neighborhood there are cooperators and defectors, the focal player is contradictorily influenced by them and, therefore, the effective social influence is given by the difference of the accumulated payoff of each strategy in its neighborhood. First, by considering the growing process of the network and neglecting mutations, we show the evolution of highly cooperative systems. Then, we broadly show that the social influence allows to overcome the emergence of defectors into highly cooperative systems. In this way, we conclude that in a structured system formed by a growing process, the cooperation evolves if the individuals have an imitation capacity socially influenced by each one of their neighbors. Therefore, here we present a theoretical solution of the cooperation problem among genetically unrelated individuals.

Researching evaluation influence: a review of the literature.

PubMed

Herbert, James Leslie

2014-10-01

The impact of an evaluation is an important consideration in designing and carrying out evaluations. Evaluation influence is a way of thinking about the effect that an evaluation can have in the broadest possible terms, which its proponents argue will lead to a systematic body of evidence about influential evaluation practices. This literature review sets out to address three research questions: How have researchers defined evaluation influence; how is this reflected in the research; and what does the research suggest about the utility of evaluation influence as a conceptual framework. Drawing on studies that had cited one of the key evaluation influence articles and conducted original research on some aspect of influence this article reviewed the current state of the literature toward the goal of developing a body of evidence about how to practice influential evaluation. Twenty-eight studies were found that have drawn on evaluation influence, which were categorized into (a) descriptive studies, (b) analytical studies, and (c) hypothesis testing. Despite the prominence of evaluation influence in the literature, there is slow progress toward a persuasive body of literature. Many of the studies reviewed offered vague and inconsistent definitions and have applied influence in an unspecified way in the research. It is hoped that this article will stimulate interest in the systematic study of influence mechanisms, leading to improvements in the potential for evaluation to affect positive social change. © The Author(s) 2014.

Inferring influence and leadership in moving animal groups.

PubMed

Strandburg-Peshkin, Ariana; Papageorgiou, Danai; Crofoot, Margaret C; Farine, Damien R

2018-05-19

Collective decision-making is a daily occurrence in the lives of many group-living animals, and can have critical consequences for the fitness of individuals. Understanding how decisions are reached, including who has influence and the mechanisms by which information and preferences are integrated, has posed a fundamental challenge. Here, we provide a methodological framework for studying influence and leadership in groups. We propose that individuals have influence if their actions result in some behavioural change among their group-mates, and are leaders if they consistently influence others. We highlight three components of influence (influence instances, total influence and consistency of influence), which can be assessed at two levels (individual-to-individual and individual-to-group). We then review different methods, ranging from individual positioning within groups to information-theoretic approaches, by which influence has been operationally defined in empirical studies, as well as how such observations can be aggregated to give insight into the underlying decision-making process. We focus on the domain of collective movement, with a particular emphasis on methods that have recently been, or are being, developed to take advantage of simultaneous tracking data. We aim to provide a resource bringing together methodological tools currently available for studying leadership in moving animal groups, as well as to discuss the limitations of current methodologies and suggest productive avenues for future research.This article is part of the theme issue 'Collective movement ecology'. © 2018 The Author(s).

Gender influencers on work values of black adolescents.

PubMed

Thomas, V G; Shields, L C

1987-01-01

Work values and key influencers of a sample of black male and female adolescents were examined. Results indicated that boys and girls valued both the intrinsic and extrinsic rewards of work; however, girls reported slighter stronger extrinsic values than did boys. In addition, the sexes reported differences in the importance of specific work values such as "making lots of money," and "doing important things." When naming a key influencer, respondents tended to cite a same-sex and race individual. Sex of one's key influencer was related to certain work values, with subjects reporting a male key influencer valuing "trying out one's own ideas" and "having a secure future" more than those reporting a female key influencer. The interaction of sex of subject and sex of key influencer was significant on one of the work value outcomes. Implications of these findings are considered.

The Influence of Momentary Goal Structures

ERIC Educational Resources Information Center

Zaleski, Diana Janet

2010-01-01

Adolescents' cognition is influenced by a dynamic educational environment. Studies examining the influence of schools, classrooms, and teachers often overlook the momentary variation found in these environments and the effect this variation has on student cognition. Using an achievement goal theory framework, this study examined the momentary…

Influence of Educational Attainment on Consumption

ERIC Educational Resources Information Center

Zhang, Xuemin; He, Youning

2007-01-01

In market economy, man is both the essential productive factor and the consuming subject. Education promotes the two aspects. As shown by investigations on the influence of educational attainment on consumption, education has great influences on people's consumption level, consumption structure, consumption modes and consumption concepts. The…

The Art of Influencing Decision Makers.

ERIC Educational Resources Information Center

Diegmueller, Karen

1992-01-01

Influencing educational decision makers requires creating ongoing relationships, keeping everyone informed, and developing persuasive skills. Persuasion requires preparation, refinement, hard work, and a sound understanding of the people being lobbied. Lobbying must be factual and relevant to the audience. The article looks at influence from the…

Leadership Influence: A Core Foundation for Advocacy.

PubMed

Shillam, Casey R; MacLean, Lola

As the largest segment of the health care workforce, nurses have the greatest potential for advancing systems and services to improve health care delivery in the United States. This article presents a framework for nurse administrators to use in developing direct care nurses in their leadership influence competency as a means of increasing their advocacy potential. A systematic review resulted in establishing a nurse leadership influence framework based on the Kouzes and Posner leadership model. The framework includes leadership competencies by nursing professional organizations and was validated by 2 national nurse leader focus groups. Nurse administrators have the opportunity to adopt an evidence-based leadership influence framework to ensure development of advocacy competency in direct care nurses. The impact of nurse administrators systematically adopting a standardized leadership influence framework will result in setting a strong foundation for nurse advocacy. Successful long-term impacts will result in nurses skillfully integrating leadership influence and advocacy into all aspects of daily practice.

[Distant mental influence on living organisms].

PubMed

Bonilla, Ernesto

2013-12-01

This article reviews studies of distant mental influence on living organisms, including mental suggestions of sleeping and awakening, mental influence at long distances, mental interactions with remote biological systems, mental effects on physiological activity and the sense of being stared at. Significant effects of distant mental influence have been shown in several randomized controlled trials in humans, animals, plants, bacteria and cells in the laboratory. Although distant mental influence on living organisms appears to contradict our ordinary sense of reality and the laws defined by conventional science, several hypotheses have been proposed to explain the observed effects; they include skeptical, signal transfer, field, multidimensional space/time and quantum mechanics hypotheses. In conclusion, as the progress of physics continues to expand our comprehension of reality, a rational explanation for distant mind-matter interaction will emerge and, as history has shown repeatedly, the supernatural events will evolve into paranormal and then, into normal ones, as the scientific frontiers expand.

High resolution modelling of the biogeochemical processes in the eutrophic Loire River (France)

NASA Astrophysics Data System (ADS)

Minaudo, Camille; Moatar, Florentina; Curie, Florence; Gassama, Nathalie; Billen, Gilles

2016-04-01

released by mineralization of the dead cells. The high resolution of the model allowed understanding some fine temporal scale events, especially during some minor flood events occurring in summer. Paradoxically such events played two opposite roles: first it was disturbing the phytoplankton by diluting the biomass and remobilizing suspended sediments; then, it indirectly re-supplied the system with more available phosphorus, mainly because the washed-out phytoplankton could not assimilate the P available upstream. The model also pointed out the significant role played by Corbicula invasive clams in the river biogeochemical functioning, substantially reducing the phytoplankton biomass, and thus impacting the nutrients, oxygen and carbon cycles. However, the temporal and spatial distribution of Corbicula was questioned, and highlighted the need for data collection on this topic.

Quantifying Proxy Influence in the Last Millennium Reanalysis

NASA Astrophysics Data System (ADS)

Hakim, G. J.; Anderson, D. N.; Emile-Geay, J.; Noone, D.; Tardif, R.

2017-12-01

We examine the influence of proxies in the climate field reconstruction known as the Last Millennium Reanalysis (Hakim et al. 2016; JGR-A). This data assimilation framework uses the CCSM4 Last Millennium simulation as an agnostic prior, proxies from the PAGES 2k Consortium (2017; Sci. Data), and an offline ensemble square-root filter for assimilation. Proxies are forward modeled using an observation model ("proxy system model") that maps from the prior space to the proxy space. We assess proxy impact using the method of Cardinali et al. (2004; QJRMS), where influence is measured in observation space; that is, at the location of observations. Influence is determined by three components: the prior at the location, the proxy at the location, and remote proxies as mediated by the spatial covariance information in the prior. Consequently, on a per-proxy basis, influence is higher for spatially isolated proxies having small error, and influence is lower for spatially dense proxies having large error. Results show that proxy influence depends strongly on the observation model. Assuming the proxies depend linearly on annual mean temperature yields the largest per-proxy influence for coral d18O and coral Sr/Ca records, and smallest influence for tree-ring width. On a global basis (summing over all proxies of a given type), tree-ring width and coral d18O have the largest influence. A seasonal model for the proxies yields very different results. In this case we model the proxies linearly on objectively determined seasonal temperature, except for tree proxies, which are fit to a bivariate model on seasonal temperature and precipitation. In this experiment, on a per-proxy basis, tree-ring density has by far the greatest influence. Total proxy influence is dominated by tree-ring width followed by tree-ring density. Compared to the results for the annual-mean observation model, the experiment where proxies are measured seasonally has more than double the total influence (sum over

Psychopathic traits moderate peer influence on adolescent delinquency.

PubMed

Kerr, Margaret; Van Zalk, Maarten; Stattin, Håkan

2012-08-01

Peer influence on adolescent delinquency is well established, but little is known about moderators of peer influence. In this study, we examined adolescents' (targets) and their peers' psychopathic personality traits as moderators of peer influence on delinquency in peer networks. We used three separate dimensions of the psychopathic personality: grandiose-manipulative traits, callous-unemotional traits, and impulsive-irresponsible traits. We used a peer network approach with five waves of longitudinal data from 847 adolescents in one community. Peer nominations were not limited to the school context, thus allowing us to capture all potentially important peers. In addition, peers reported on their own delinquency, thus allowing us to avoid problems of false consensus or projection that arise when individuals report on their peers' delinquency. We used simulation investigation for empirical network analyses (SIENA), which is the only program currently available that can be used to study peer influence effects in peer networks of multiple relationships while controlling for selection effects. Targets' and peers' callous-unemotional and grandiose-manipulative traits uniquely moderated peer influence on delinquency. Relative to those with low levels, targets who were high on these traits were less influenced by peers' delinquency, and peers who were high on these traits were more influential on targets' delinquency. Selection effects were found for impulsive-irresponsible traits, but these traits did not moderate peer influence on delinquency. As the first study to look at moderating effects of psychopathic traits on peer influence, this study advances knowledge about peer influence on delinquency and about psychopathic traits in adolescents. In addition, the study contributes to the literature by looking at unique effects of the three dimensions of psychopathy and taking a peer network approach, in which network effects, self-selection, and other selection effects are

The Influence of Poverty on Achievement

ERIC Educational Resources Information Center

Tienken, Christopher H.

2012-01-01

Without a doubt, poverty has a negative influence on student achievement, especially when achievement is measured by state-mandated standardized tests. However, some bureaucrats, such as state commissioners of education and even state governors, continue to downplay the influence of poverty on student achievement. New Jersey's Governor Chris…

Being Influenced or Being an Influence: New Teachers' Induction Experiences

ERIC Educational Resources Information Center

Keay, Jeanne

2009-01-01

This article draws on and develops the outcomes of previous research which concluded that school subject departments provide the setting for influential professional development and that experienced teachers strongly influence their newly qualified colleagues. The findings of two subsequent research projects, which used this as a starting point,…

Influence of toxic endophyte-infected fescue on sperm characteristics and endocrine factors of yearling Brahman-influenced bulls

USDA-ARS?s Scientific Manuscript database

Sixteen (mean age = 1.1 +/- 0.1 yr; mean BW = 478 +/- 34 kg) Brahman-influenced bulls were used to determine the influence of fescue type on sperm characteristics and serum concentrations of prolactin, cortisol, and testosterone. Bulls were blocked by BW, scrotal circumference (SC), and pregrazing...

An imaging genetics approach to understanding social influence

PubMed Central

Falk, Emily B.; Way, Baldwin M.; Jasinska, Agnes J.

2012-01-01

Normative social influences shape nearly every aspect of our lives, yet the biological processes mediating the impact of these social influences on behavior remain incompletely understood. In this Hypothesis, we outline a theoretical framework and an integrative research approach to the study of social influences on the brain and genetic moderators of such effects. First, we review neuroimaging evidence linking social influence and conformity to the brain's reward system. We next review neuroimaging evidence linking social punishment (exclusion) to brain systems involved in the experience of pain, as well as evidence linking exclusion to conformity. We suggest that genetic variants that increase sensitivity to social cues may predispose individuals to be more sensitive to either social rewards or punishments (or potentially both), which in turn increases conformity and susceptibility to normative social influences more broadly. To this end, we review evidence for genetic moderators of neurochemical responses in the brain, and suggest ways in which genes and pharmacology may modulate sensitivity to social influences. We conclude by proposing an integrative imaging genetics approach to the study of brain mediators and genetic modulators of a variety of social influences on human attitudes, beliefs, and actions. PMID:22701416

Hannelore Wass: Professional Influences and Legacies.

PubMed

Corr, Charles A

2015-01-01

This article offers a reflection on the professional influence of Dr. Hannelore Wass on the author's introduction to and work in the field of death, dying, and bereavement. At the same time, it also offers comments on her broader influence on and legacies left to others who work in this field.

Genetic and environmental influences on thin-ideal internalization.

PubMed

Suisman, Jessica L; O'Connor, Shannon M; Sperry, Steffanie; Thompson, J Kevin; Keel, Pamela K; Burt, S Alexandra; Neale, Michael; Boker, Steven; Sisk, Cheryl; Klump, Kelly L

2012-12-01

Current research on the etiology of thin-ideal internalization focuses on psychosocial influences (e.g., media exposure). The possibility that genetic influences also account for variance in thin-ideal internalization has never been directly examined. This study used a twin design to estimate genetic effects on thin-ideal internalization and examine if environmental influences are primarily shared or nonshared in origin. Participants were 343 postpubertal female twins (ages: 12-22 years; M = 17.61) from the Michigan State University Twin Registry. Thin-ideal internalization was assessed using the Sociocultural Attitudes toward Appearance Questionnaire-3. Twin modeling suggested significant additive genetic and nonshared environmental influences on thin-ideal internalization. Shared environmental influences were small and non-significant. Although prior research focused on psychosocial factors, genetic influences on thin-ideal internalization were significant and moderate in magnitude. Research is needed to investigate possible interplay between genetic and nonshared environmental factors in the development of thin-ideal internalization. Copyright © 2012 Wiley Periodicals, Inc.

Measurement and associations of pregnancy risk factors with genetic influences, postnatal environmental influences, and toddler behavior

PubMed Central

Marceau, Kristine; Hajal, Nastassia; Leve, Leslie D.; Reiss, David; Shaw, Daniel S.; Ganiban, Jody M.; Mayes, Linda C.; Neiderhiser, Jenae M.

2014-01-01

This study demonstrates the unique contributions of perinatal risk and genetic and environmental influences on child behavior using data from 561 domestic US adoption triads (birth mothers, adopted child, and adoptive parents). Findings show distinct patterns of associations among genetic (birth mother psychopathology), prenatal (six maternal reported aggregate scores characterizing total obstetric complications, perinatal internalizing symptoms, pregnancy complications, exposure to toxins, substance use, and neonatal complications), and postnatal influences (adoptive parent 18-month internalizing symptoms and over-reactive parenting) and toddler behavior problems (CBCL subscales at 27 months). Findings highlight multiple pathways for toddler’s behavioral development, including genetic, pregnancy, and postnatal main effects. Findings suggest distinct types of pregnancy risk may transmit genetic influences for specific behavior problems rather than broadband problems. PMID:24839336

Psychopathic Traits Moderate Peer Influence on Adolescent Delinquency

ERIC Educational Resources Information Center

Kerr, Margaret; Van Zalk, Maarten; Stattin, Hakan

2012-01-01

Background: Peer influence on adolescent delinquency is well established, but little is known about moderators of peer influence. In this study, we examined adolescents' (targets) and their peers' psychopathic personality traits as moderators of peer influence on delinquency in peer networks. We used three separate dimensions of the psychopathic…

The Feynman-Vernon Influence Functional Approach in QED

NASA Astrophysics Data System (ADS)

Biryukov, Alexander; Shleenkov, Mark

2016-10-01

In the path integral approach we describe evolution of interacting electromagnetic and fermionic fields by the use of density matrix formalism. The equation for density matrix and transitions probability for fermionic field is obtained as average of electromagnetic field influence functional. We obtain a formula for electromagnetic field influence functional calculating for its various initial and final state. We derive electromagnetic field influence functional when its initial and final states are vacuum. We present Lagrangian for relativistic fermionic field under influence of electromagnetic field vacuum.

Relative Influence of Professional Counseling Journals

ERIC Educational Resources Information Center

Fernando, Delini M.; Barrio Minton, Casey A.

2011-01-01

The authors used social network analysis of citation data to study the flow of information and relative influence of 17 professional counseling journals. Although the "Journal of Counseling & Development" ranked very highly in all measures of journal influence, several division journals emerged as key players in the flow of information within the…

Robust Bounded Influence Tests in Linear Models

DTIC Science & Technology

1988-11-01

sensitivity analysis and bounded influence estimation. In: Evaluation of Econometric Models, J. Kmenta and J.B. Ramsey (eds.) Academic Press, New York...1R’OBUST bOUNDED INFLUENCE TESTS IN LINEA’ MODELS and( I’homas P. [lettmansperger* Tim [PennsylvanLa State UJniversity A M i0d fix pu111 rsos.p JJ 1 0...November 1988 ROBUST BOUNDED INFLUENCE TESTS IN LINEAR MODELS Marianthi Markatou The University of Iowa and Thomas P. Hettmansperger* The Pennsylvania

Low cloud properties influenced by cosmic rays

PubMed

Marsh; Svensmark

2000-12-04

The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (

A Maternal Influence on Reading the Mind in the Eyes Mediated by Executive Function: Differential Parental Influences on Full and Half-Siblings

PubMed Central

Ragsdale, Gillian; Foley, Robert A.

2011-01-01

Background Parent-of-origin effects have been found to influence the mammalian brain and cognition and have been specifically implicated in the development of human social cognition and theory of mind. The experimental design in this study was developed to detect parent-of-origin effects on theory of mind, as measured by the ‘Reading the mind in the eyes’ (Eyes) task. Eyes scores were also entered into a principal components analysis with measures of empathy, social skills and executive function, in order to determine what aspect of theory of mind Eyes is measuring. Methodology/Principal Findings Maternal and paternal influences on Eyes scores were compared using correlations between pairs of full (70 pairs), maternal (25 pairs) and paternal siblings (15 pairs). Structural equation modelling supported a maternal influence on Eyes scores over the normal range but not low-scoring outliers, and also a sex-specific influence on males acting to decrease male Eyes scores. It was not possible to differentiate between genetic and environmental influences in this particular sample because maternal siblings tended to be raised together while paternal siblings were raised apart. The principal components analysis found Eyes was associated with measures of executive function, principally behavioural inhibition and attention, rather than empathy or social skills. Conclusions/Significance In conclusion, the results suggest a maternal influence on Eye scores in the normal range and a sex-specific influence acting to reduce scores in males. This influence may act via aspects of executive function such as behavioural inhibition and attention. There may be different influences acting to produce the lowest Eyes scores which implies that the heratibility and/or maternal influence on poor theory of mind skills may be qualitatively different to the influence on the normal range. PMID:21850264

Impact of external influences on food packaging.

PubMed

Brody, A L

1977-09-01

Since the food supply is dependent upon an effective packaging system, threats to packaging represent implied threats to food processing and distribution. Enacted and potential legislation and regulation are retarding technological and commercial progress in food packaging and have already restricted some food packaging/processins systems. The results of these external influences is not simply the sum of the individual acts, but is a cascading self-imposed arresting of food packaging/processing advancement. The technological bases for the enacted and proposed legislation and regulation are presented in the enumeration of the external influences on food packaging. Economic and sociological arguments and facts surrounding the issues are also presented. Among the external influences on food packaging detailed are indirect additives, nutritional labeling, benefit:risk, solid waste and litter, environmental pollution, universal product code, and food industry productivity. The magnitude of the total impact of these external influences upon the food supply is so large that assertive action must be taken to channel these influences into more productive awareness. An objective and comprehensive public communications program supported by the technological community appears mandatory.

Informational and Normative Influences in Conformity from a Neurocomputational Perspective.

PubMed

Toelch, Ulf; Dolan, Raymond J

2015-10-01

We consider two distinct influences that drive conformity behaviour. Whereas informational influences facilitate adaptive and accurate responses, normative influences bias decisions to enhance social acceptance. We explore these influences from a perspective of perceptual and value-based decision-making models and apply these models to classical works on conformity. We argue that an informational account predicts a surprising tendency to conform. Moreover, we detail how normative influences fit into this framework and interact with social influences. Finally, we explore potential neuronal substrates for informational and normative influences based on a consideration of the neurobiological literature, highlighting conceptual shortcomings particularly with regard to a failure to segregate informational and normative influences. Copyright © 2015 Elsevier Ltd. All rights reserved.

Computing the structural influence matrix for biological systems.

PubMed

Giordano, Giulia; Cuba Samaniego, Christian; Franco, Elisa; Blanchini, Franco

2016-06-01

We consider the problem of identifying structural influences of external inputs on steady-state outputs in a biological network model. We speak of a structural influence if, upon a perturbation due to a constant input, the ensuing variation of the steady-state output value has the same sign as the input (positive influence), the opposite sign (negative influence), or is zero (perfect adaptation), for any feasible choice of the model parameters. All these signs and zeros can constitute a structural influence matrix, whose (i, j) entry indicates the sign of steady-state influence of the jth system variable on the ith variable (the output caused by an external persistent input applied to the jth variable). Each entry is structurally determinate if the sign does not depend on the choice of the parameters, but is indeterminate otherwise. In principle, determining the influence matrix requires exhaustive testing of the system steady-state behaviour in the widest range of parameter values. Here we show that, in a broad class of biological networks, the influence matrix can be evaluated with an algorithm that tests the system steady-state behaviour only at a finite number of points. This algorithm also allows us to assess the structural effect of any perturbation, such as variations of relevant parameters. Our method is applied to nontrivial models of biochemical reaction networks and population dynamics drawn from the literature, providing a parameter-free insight into the system dynamics.

The influence of logical positivism on nursing practice.

PubMed

Whall, A L

1989-01-01

While logical positivism has been said to have had major influence on the development of nursing theory, whether this influence pervades other aspects of the discipline has not been discussed. One central aspect of logical positivism, the verificationist perspective, was used to examine texts, curricular guides and standards of practice that guided nursing practice in the decades in which logical positivism had influence on nursing theory construction. This review of the literature does not support the influence of logical positivism, as exemplified by the verificationist perspective, on nursing practice guidelines.

Social influences on reality-monitoring decisions.

PubMed

Hoffman, H G; Granhag, P A; Kwong See, S T; Loftus, E F

2001-04-01

A modified Asch (1951) conformity paradigm was used to study the impact of social influence on reality-monitoring decisions about new items. Subjects studied pictures of some objects and imagined others. In a later test phase, they judged whether items had been perceived in the study phase, had been imagined, or were new. Critically, for some items, the subjects were informed of a confederate's response before rendering a judgment. Although the confederate was always correct when they responded to old items, for new items, the confederate responded perceived, imagined, or new, or did not respond (baseline). In two experiments, we show that memory for new items was influenced by an erroneous response of the confederate. Social conformity was reduced by undermining the credibility of the confederate (Experiments 1A and 1B), and the confederate's influence was evident even after there was only a 20-min delay between study and test (Experiment 2), when the subjects were 87% accurate on new baseline items. These experiments reveal the power of social influence on reality-monitoring accuracy and confidence.

Statistical mechanics of influence maximization with thermal noise

NASA Astrophysics Data System (ADS)

Lynn, Christopher W.; Lee, Daniel D.

2017-03-01

The problem of optimally distributing a budget of influence among individuals in a social network, known as influence maximization, has typically been studied in the context of contagion models and deterministic processes, which fail to capture stochastic interactions inherent in real-world settings. Here, we show that by introducing thermal noise into influence models, the dynamics exactly resemble spins in a heterogeneous Ising system. In this way, influence maximization in the presence of thermal noise has a natural physical interpretation as maximizing the magnetization of an Ising system given a budget of external magnetic field. Using this statistical mechanical formulation, we demonstrate analytically that for small external-field budgets, the optimal influence solutions exhibit a highly non-trivial temperature dependence, focusing on high-degree hub nodes at high temperatures and on easily influenced peripheral nodes at low temperatures. For the general problem, we present a projected gradient ascent algorithm that uses the magnetic susceptibility to calculate locally optimal external-field distributions. We apply our algorithm to synthetic and real-world networks, demonstrating that our analytic results generalize qualitatively. Our work establishes a fruitful connection with statistical mechanics and demonstrates that influence maximization depends crucially on the temperature of the system, a fact that has not been appreciated by existing research.

Factors Influencing Adults' Environmental Attitudes and Behaviors and the Role of Environmental Schools in Influencing Their Communities

ERIC Educational Resources Information Center

Eilam, Efrat; Trop, Tamar

2014-01-01

The present study revisits a subfield of environmental education: significant life experiences, which studies the influences that shape the development of environmental stewardship. In the present study, we examine the effect of various formative experiences on a group of adults and analyze the role of school, as a formative influence on the…

Avenues of Influence: Cross-Cultural Implications

DTIC Science & Technology

2014-04-01

focused on comparisons between individualistic and collectivistic cultures . Furthermore, given the differential emphasis toward group factors in...either individualistic or collectivistic cultures , social influence tactics involving group social elements may be a good starting point for exploring...in Two Cultures : The Differential Influence of Social Proof and Commitment/Consistency on collectivists and Individualists . Personality and Social

Pressure Scalings and Influence Region Research

DTIC Science & Technology

2018-01-01

the results are briefly discussed. Additionally, updated experimental results are presented along with discussion of collaborative research efforts...with upstream and downstream influence, where the influence lengths are defined in terms of a-priori quantities (freestream conditions and...governing equations and the result is briefly discussed. Additionally, updated experimental results are presented along with discussion of

Influence analysis of Github repositories.

PubMed

Hu, Yan; Zhang, Jun; Bai, Xiaomei; Yu, Shuo; Yang, Zhuo

2016-01-01

With the support of cloud computing techniques, social coding platforms have changed the style of software development. Github is now the most popular social coding platform and project hosting service. Software developers of various levels keep entering Github, and use Github to save their public and private software projects. The large amounts of software developers and software repositories on Github are posing new challenges to the world of software engineering. This paper tries to tackle one of the important problems: analyzing the importance and influence of Github repositories. We proposed a HITS based influence analysis on graphs that represent the star relationship between Github users and repositories. A weighted version of HITS is applied to the overall star graph, and generates a different set of top influential repositories other than the results from standard version of HITS algorithm. We also conduct the influential analysis on per-month star graph, and study the monthly influence ranking of top repositories.

Antecedent influences on behavior disorders.

PubMed Central

Smith, R G; Iwata, B A

1997-01-01

The influence of antecedent events on behavior disorders has been relatively understudied by applied behavior analysts. This lack of research may be due to a focus on consequences as determinants of behavior and a historical disagreement on a conceptual framework for describing and interpreting antecedent variables. We suggest that antecedent influences can be described using terms derived from basic behavioral principles and that their functional properties can be adequately interpreted as discriminative and establishing operations. A set of studies on assessment and treatment of behavior disorders was selected for review based on their relevance to the topic of antecedent events. These studies were categorized as focusing on assessment of antecedent events, antecedent treatments for behavior disorders maintained by either positive or negative reinforcement, and special cases of antecedent events in behavior disorders. Some directions for future research on antecedent influences in the analysis and treatment of behavior disorders are discussed. PMID:9210312

Environmental influences: factors influencing a woman's decision to use dietary supplements.

PubMed

Conner, Mark; Kirk, Sara F L; Cade, Janet E; Barrett, Jennifer H

2003-06-01

Use of dietary supplements by women, particularly those over 40 years of age may be widespread in the United Kingdom. However, from surveillance data, there appears to be a disparity between nutrition and health needs and the rationale for and actual use of dietary supplements by women. This apparent paradox forms the basis for an inverse supplement hypothesis (i.e., supplement use in women appears to be most prevalent among those with least need). Little research has been done to examine the factors underlying the decision to use dietary supplements. Reasons for consuming dietary supplements are often complex, combining social, psychological, knowledge and economic factors. The theory of planned behavior is a widely used model for assessing factors influencing behavioral motivation and action that may be useful for assessing specific diet- and nutrition-related practices. It provided the basis for the development of a questionnaire to explore overall dietary supplement use in a cohort of women in the United Kingdom. The analysis of factors related to beliefs underlying dietary supplement use revealed differences between supplement users and nonusers. Differences included a stronger belief by users than nonusers that taking dietary supplements ensures against possible ill health. Both users and nonusers of supplements also perceived the media (books and magazines) to be a powerful influence on a person's decision to use supplements. These findings highlight the potential of the theory of planned behavior in exploring supplement-taking behavior while throwing light on the factors influencing an individual's motivations to use dietary supplements.

Influences Preceding "Nunatsiavut" Self-Determination: Historical, Political and Educational Influences on the People of Northern Labrador (Canada)

ERIC Educational Resources Information Center

Anderson, Kirk David

2007-01-01

What were the influences on the Inuit of Northern Labrador preceding the creation of the self-governing territory of Nunatsiavut? What are the preterritorial influences of the Inuit on the territory's five schools? To answer these questions and to share the success of one Indigenous people, the Nunatsiavut Inuit (the Inuit of Northern Labrador,…

Avenues of Influence Cross-Cultural Implications (Briefing Charts)

DTIC Science & Technology

2012-11-01

cultural , Social Influence, Communication modality, Emotional contagion, Individualistic , Collectivistic , Group orientation, Behavioral influences 16...appeals to take additional training – Culture groups: Individualistic and Collectivistic – Six persuasive appeals will be used in the stimuli: rational...between media type and emotional contagion Does culture influence the impact of social proof? H4: Collectivistic cultures will engage in

Reservoir area of influence and implications for fisheries management

USGS Publications Warehouse

Martin, Dustin R.; Chizinski, Christopher J.; Pope, Kevin L.

2015-01-01

Understanding the spatial area that a reservoir draws anglers from, defined as the reservoir's area of influence, and the potential overlap of that area of influence between reservoirs is important for fishery managers. Our objective was to define the area of influence for reservoirs of the Salt Valley regional fishery in southeastern Nebraska using kernel density estimation. We used angler survey data obtained from in-person interviews at 17 reservoirs during 2009–2012. The area of influence, defined by the 95% kernel density, for reservoirs within the Salt Valley regional fishery varied, indicating that anglers use reservoirs differently across the regional fishery. Areas of influence reveal angler preferences in a regional context, indicating preferred reservoirs with a greater area of influence. Further, differences in areas of influences across time and among reservoirs can be used as an assessment following management changes on an individual reservoir or within a regional fishery. Kernel density estimation provided a clear method for creating spatial maps of areas of influence and provided a two-dimensional view of angler travel, as opposed to the traditional mean travel distance assessment.

Some temperature influences on levels and theodolites.

NASA Astrophysics Data System (ADS)

Milovanović, V.; Blagojević, D.

1996-11-01

This work was instigated by some recent investigations on deformations of instrumental parts caused by temperature influences. The authors have considered the importance of temperature influences on levels and theodolites, as well as possibilities for their elimination.

Analyzing the sources and nature of influence: how the Avahan program used evidence to influence HIV/AIDS prevention policy in India.

PubMed

Tran, Nhan T; Bennett, Sara C; Bishnu, Rituparna; Singh, Suneeta

2013-04-17

Major investments by development partners in low- and middle-income countries (LMICs) often seek to develop a supportive policy environment. There is limited knowledge about the mechanisms that development partners use to influence government policy, or which mechanisms are effective. This study assessed the influence of Avahan, a large HIV/AIDS prevention program in India supported by the Bill and Melinda Gates Foundation, on the development of HIV/AIDS policies in India, particularly the National AIDS Control Program III (NACP III). A retrospective assessment of the contributions of Avahan to the development of NACP III was conducted based upon document review and in-depth interviews with key informants, including Avahan staff and staff of implementing partners. This assessment was carried out within a framework centered on three domains: evidence considered by policy and decision-makers; the channel through which influence is exerted; and the target audience for influence. Respondents identified a number of respects in which Avahan influenced NACP III policy, notably, Avahan influenced perception of the feasibility of scaling up services (through a demonstration effect) and Avahan, along with others, helped ensure a strong focus on targeted interventions. Overall Avahan's influence was greatest during policy implementation. While the extent to which research evidence generated by Avahan influenced NACP III was limited, best practice evidence generated by Avahan, including the lessons learned from routine implementation and management, contributed significantly to NACP III. This was largely due to the credibility Avahan had established and strategic 'inside track' communications. While studies of knowledge translation typically focus primarily on scientific evidence, this study suggests that other forms of evidence, notably best practice evidence derived from program experience, and disseminated through personal communication, were particularly influential. The

Affective Beliefs Influence the Experience of Eating Meat

PubMed Central

Anderson, Eric C.; Barrett, Lisa Feldman

2016-01-01

People believe they experience the world objectively, but research continually demonstrates that beliefs influence perception. Emerging research indicates that beliefs influence the experience of eating. In three studies, we test whether beliefs about how animals are raised can influence the experience of eating meat. Samples of meat were paired with descriptions of animals raised on factory farms or raised on humane farms. Importantly, the meat samples in both conditions were identical. However, participants experienced the samples differently: meat paired with factory farm descriptions looked, smelled, and tasted less pleasant. Even basic properties of flavor were influenced: factory farmed samples tasted more salty and greasy. Finally, actual behavior was influenced: participants consumed less when samples were paired with factory farm descriptions. These findings demonstrate that the experience of eating is not determined solely by physical properties of stimuli—beliefs also shape experience. PMID:27556643

Exogenous spatial attention influences figure-ground assignment.

PubMed

Vecera, Shaun P; Flevaris, Anastasia V; Filapek, Joseph C

2004-01-01

In a hierarchical stage account of vision, figure-ground assignment is thought to be completed before the operation of focal spatial attention. Results of previous studies have supported this account by showing that unpredictive, exogenous spatial precues do not influence figure-ground assignment, although voluntary attention can influence figure-ground assignment. However, in these studies, attention was not summoned directly to a region in a figure-ground display. In three experiments, we addressed the relationship between figure-ground assignment and visuospatial attention. In Experiment 1, we replicated the finding that exogenous precues do not influence figure-ground assignment when they direct attention outside of a figure-ground stimulus. In Experiment 2, we demonstrated that exogenous attention can influence figure-ground assignment if it is directed to one of the regions in a figure-ground stimulus. In Experiment 3, we demonstrated that exogenous attention can influence figure-ground assignment in displays that contain a Gestalt figure-ground cue; this result suggests that figure-ground processes are not entirely completed prior to the operation of focal spatial attention. Exogenous spatial attention acts as a cue for figure-ground assignment and can affect the outcome of figure-ground processes.

Influences on the prescribing of new drugs.

PubMed

Tobin, Luke; de Almedia Neto, Abelio C; Wutzke, Sonia; Patterson, Craig; Mackson, Judith; Weekes, Lynn; Williamson, Margaret

2008-01-01

The aim of this study was to identify the factors that influence prescribing of new drugs among general practitioners, endocrinologists and psychiatrists. Four focus groups were conducted with GPs, endocrinologists and psychiatrists on sources of awareness and influences on prescribing of new drugs. Pharmaceutical companies were the most important source for becoming aware of new drugs. There were many influences on the decision to prescribe a new drug, the most important being efficacy, safety, cost and advantage over existing therapies. Endocrinologists placed greater emphasis on evidence from clinical trials and scientific conferences, and psychiatrists and GPs placed more weight on pharmaceutical representatives, colleagues and specialists. New drug prescribing occurs in a complex environment with many influences. Effective interventions to promote rational, safe and effective prescribing of new drugs will need to be cognisant of these factors.

A Survey of Models and Algorithms for Social Influence Analysis

NASA Astrophysics Data System (ADS)

Sun, Jimeng; Tang, Jie

Social influence is the behavioral change of a person because of the perceived relationship with other people, organizations and society in general. Social influence has been a widely accepted phenomenon in social networks for decades. Many applications have been built based around the implicit notation of social influence between people, such as marketing, advertisement and recommendations. With the exponential growth of online social network services such as Facebook and Twitter, social influence can for the first time be measured over a large population. In this chapter, we survey the research on social influence analysis with a focus on the computational aspects. First, we present statistical measurements related to social influence. Second, we describe the literature on social similarity and influences. Third, we present the research on social influence maximization which has many practical applications including marketing and advertisement.

Influence plots for LASSO

DOE PAGES

Jang, Dae -Heung; Anderson-Cook, Christine Michaela

2016-11-22

With many predictors in regression, fitting the full model can induce multicollinearity problems. Least Absolute Shrinkage and Selection Operation (LASSO) is useful when the effects of many explanatory variables are sparse in a high-dimensional dataset. Influential points can have a disproportionate impact on the estimated values of model parameters. Here, this paper describes a new influence plot that can be used to increase understanding of the contributions of individual observations and the robustness of results. This can serve as a complement to other regression diagnostics techniques in the LASSO regression setting. Using this influence plot, we can find influential pointsmore » and their impact on shrinkage of model parameters and model selection. Lastly, we provide two examples to illustrate the methods.« less

Influence plots for LASSO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Dae -Heung; Anderson-Cook, Christine Michaela

With many predictors in regression, fitting the full model can induce multicollinearity problems. Least Absolute Shrinkage and Selection Operation (LASSO) is useful when the effects of many explanatory variables are sparse in a high-dimensional dataset. Influential points can have a disproportionate impact on the estimated values of model parameters. Here, this paper describes a new influence plot that can be used to increase understanding of the contributions of individual observations and the robustness of results. This can serve as a complement to other regression diagnostics techniques in the LASSO regression setting. Using this influence plot, we can find influential pointsmore » and their impact on shrinkage of model parameters and model selection. Lastly, we provide two examples to illustrate the methods.« less

Collective influence in evolutionary social dilemmas

NASA Astrophysics Data System (ADS)

Szolnoki, Attila; Perc, Matjaž

2016-03-01

When evolutionary games are contested in structured populations, the degree of each player in the network plays an important role. If they exist, hubs often determine the fate of the population in remarkable ways. Recent research based on optimal percolation in random networks has shown, however, that the degree is neither the sole nor the best predictor of influence in complex networks. Low-degree nodes may also be optimal influencers if they are hierarchically linked to hubs. Taking this into account leads to the formalism of collective influence in complex networks, which as we show here, has far-reaching implications for the favorable resolution of social dilemmas. In particular, there exists an optimal hierarchical depth for the determination of collective influence that we use to describe the potency of players for passing their strategies, which depends on the strength of the social dilemma. Interestingly, the degree, which corresponds to the baseline depth zero, is optimal only when the temptation to defect is small. Our research reveals that evolutionary success stories are related to spreading processes which are rooted in favorable hierarchical structures that extend beyond local neighborhoods.

Social Influences in Sequential Decision Making

PubMed Central

Schöbel, Markus; Rieskamp, Jörg; Huber, Rafael

2016-01-01

People often make decisions in a social environment. The present work examines social influence on people’s decisions in a sequential decision-making situation. In the first experimental study, we implemented an information cascade paradigm, illustrating that people infer information from decisions of others and use this information to make their own decisions. We followed a cognitive modeling approach to elicit the weight people give to social as compared to private individual information. The proposed social influence model shows that participants overweight their own private information relative to social information, contrary to the normative Bayesian account. In our second study, we embedded the abstract decision problem of Study 1 in a medical decision-making problem. We examined whether in a medical situation people also take others’ authority into account in addition to the information that their decisions convey. The social influence model illustrates that people weight social information differentially according to the authority of other decision makers. The influence of authority was strongest when an authority's decision contrasted with private information. Both studies illustrate how the social environment provides sources of information that people integrate differently for their decisions. PMID:26784448

Social Influences in Sequential Decision Making.

PubMed

Schöbel, Markus; Rieskamp, Jörg; Huber, Rafael

2016-01-01

People often make decisions in a social environment. The present work examines social influence on people's decisions in a sequential decision-making situation. In the first experimental study, we implemented an information cascade paradigm, illustrating that people infer information from decisions of others and use this information to make their own decisions. We followed a cognitive modeling approach to elicit the weight people give to social as compared to private individual information. The proposed social influence model shows that participants overweight their own private information relative to social information, contrary to the normative Bayesian account. In our second study, we embedded the abstract decision problem of Study 1 in a medical decision-making problem. We examined whether in a medical situation people also take others' authority into account in addition to the information that their decisions convey. The social influence model illustrates that people weight social information differentially according to the authority of other decision makers. The influence of authority was strongest when an authority's decision contrasted with private information. Both studies illustrate how the social environment provides sources of information that people integrate differently for their decisions.

INFLUENCE OF HEALTH TECHNOLOGY ASSESSMENT AND ITS MEASUREMENT.

PubMed

Hailey, David; Werkö, Sophie; Rosén, Måns; Macpherson, Karen; Myles, Susan; Gallegos Rivero, Verónica; Hipólito-Olivares, Cecilia; Sihvo, Sinikka; Pwu, Jasmine; Yang, Wen-Wen; Chen, Yong-Chen; Perez Galán, Ana; Aleman, Alicia; Villamil, Elena

2016-01-01

The aim of this study was to obtain information on methods used to measure health technology assessment (HTA) influence, decisions that were influenced, and outcomes linked to HTA. Electronic databases were used to locate studies in which HTA influence had been demonstrated. Inclusion criteria were studies that reliably reported consideration by decision makers of HTA findings; comparative studies of technology use before and after HTA; and details of changes in policy, health outcomes, or research that could be credibly linked to an HTA. Fifty-one studies were selected for review. Settings were national (24), regional (12), both national and regional (3) hospitals (9), and multinational (3). The most common approach to appraisal of influence was review of policy or administrative decisions following HTA recommendations (51 percent). Eighteen studies (35 percent) reported interview or survey findings, thirteen (26 percent) reviewed administrative data, and six considered the influence of primary studies. Of 142 decisions informed by HTA, the most common types were on routine clinical practice (67 percent of studies), coverage (63 percent), and program operation (37 percent). The most frequent indications of HTA influence were on decisions related to resource allocation (59 percent), change in practice pattern (31 percent), and incorporation of HTA details in reference material (18 percent). Few publications assessed the contribution of HTA to changing patient outcomes. The literature on HTA influence remains limited, with little on longer term effects on practice and outcomes. The reviewed publications indicated how HTA is being used in different settings and approaches to measuring its influence that might be more widely applied, such as surveys and monitoring administrative data.

Evidence-based Kernels: Fundamental Units of Behavioral Influence

PubMed Central

Biglan, Anthony

2008-01-01

This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior–influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of its components would render it inert. Existing evidence shows that a variety of kernels can influence behavior in context, and some evidence suggests that frequent use or sufficient use of some kernels may produce longer lasting behavioral shifts. The analysis of kernels could contribute to an empirically based theory of behavioral influence, augment existing prevention or treatment efforts, facilitate the dissemination of effective prevention and treatment practices, clarify the active ingredients in existing interventions, and contribute to efficiently developing interventions that are more effective. Kernels involve one or more of the following mechanisms of behavior influence: reinforcement, altering antecedents, changing verbal relational responding, or changing physiological states directly. The paper describes 52 of these kernels, and details practical, theoretical, and research implications, including calling for a national database of kernels that influence human behavior. PMID:18712600

The influence of communications on transportation in the future.

DOT National Transportation Integrated Search

1984-01-01

The report examines the influences of communication on transportation from various points of view. First, the historical influences are discussed as they occurred in the United States between 1776 and the present. Second, probable influences to the y...

Common contextual influences in ambiguous and rivalrous figures

PubMed Central

Jennings, Ben J.; Kingdom, Frederick A. A.

2017-01-01

Images that resist binocular fusion undergo alternating periods of dominance and suppression, similarly to ambiguous figures whose percepts alternate between two interpretations. It has been well documented that the perceptual interpretations of both rivalrous and ambiguous figures are influenced by their spatio-temporal context. Here we consider whether an identical spatial context similarly influences the interpretation of a similar rivalrous and ambiguous figure. We developed a binocularly rivalrous stimulus whose perceptual experience mirrors that of a Necker cube. We employed a paradigm similar to that of Ouhnana and Kingdom (2016) to correlate the magnitude of influence of context between the rivalrous and ambiguous target. Our results showed that the magnitude of contextual influence is significantly correlated within observers between both binocularly rivalrous and ambiguous target figures. This points to a similar contextual-influence mechanism operating on a common mechanism underlying the perceptual instability in both ambiguous and rivalrous figures. PMID:28459854

Individual and environmental influences on adolescent eating behaviors.

PubMed

Story, Mary; Neumark-Sztainer, Dianne; French, Simone

2002-03-01

Food choices of adolescents are not consistent with the Dietary Guidelines for Americans. Food intakes tend to be low in fruits, vegetables, and calcium-rich foods and high in fat. Skipping meals is also a concern among adolescents, especially girls. Factors influencing eating behaviors of adolescents need to be better understood to develop effective nutrition interventions to change eating behaviors. This article presents a conceptual model based on social cognitive theory and an ecological perspective for understanding factors that influence adolescent eating behaviors and food choices. In this model, adolescent eating behavior is conceptualized as a function of individual and environmental influences. Four levels of influence are described: individual or intrapersonal influences (eg, psychosocial, biological); social environmental or interpersonal (eg, family and peers); physical environmental or community settings (eg, schools, fast food outlets, convenience stores); and macrosystem or societal (eg, mass media, marketing and advertising, social and cultural norms).

Sources of influence on medical practice

PubMed Central

Fernandez, L. A.; Martin, J. M.; del Castillo, J. d. D. L.; Gaspar, O. S.; Millan, J. I.; Lozano, M. J.; Keenoy, E. D.

2000-01-01

OBJECTIVES—To explore the opinion of general practitioners on the importance and legitimacy of sources of influence on medical practice.
METHODS—General practitioners (n=723) assigned to Primary Care Teams (PCTs) in two Spanish regions were randomly selected to participate in this study. A self administered questionnaire was sent by mail and collected by hand. The dependent variable collected the opinion on different sources that exert influence on medical practice. Importance was measured with a 9 item scale while legitimacy was evaluated with 16 items measured with a 1 to 7 point Likert scale.
RESULTS—The most important and legitimate sources of influence according to general practitioners were: training courses and scientific articles, designing self developed protocols and discussing with colleagues. The worst evaluated were: financial incentives and the role played by the pharmaceutical industry.
CONCLUSIONS—The development of medical practice is determined by many factors, grouped around three big areas: organisational setting, professional system and social setting. The medical professional system is the one considered as being the most important and legitimate by general practitioners. Other strategies of influence, considered to be very important by the predominant management culture (financial incentives), are not considered to be so by general practitioners. These results, however, are not completely reliable as regards the real network of influences existing in medical practice, which reflect instead different "value systems".


Keywords: primary health care; physicians' practice patterns; medical practice management; physicians' incentive plans PMID:10890875

A Network Method of Measuring Affiliation-Based Peer Influence: Assessing the Influences of Teammates' Smoking on Adolescent Smoking

ERIC Educational Resources Information Center

Fujimoto, Kayo; Unger, Jennifer B.; Valente, Thomas W.

2012-01-01

Using a network analytic framework, this study introduces a new method to measure peer influence based on adolescents' affiliations or 2-mode social network data. Exposure based on affiliations is referred to as the "affiliation exposure model." This study demonstrates the methodology using data on young adolescent smoking being influenced by…

Hotel housekeeping work influences on hypertension management.

PubMed

Sanon, Marie-Anne

2013-12-01

Characteristics of hotel housekeeping work increase the risk for hypertension development. Little is known about the influences of such work on hypertension management. For this qualitative study, 27 Haitian immigrant hotel housekeepers from Miami-Dade County, FL were interviewed. Interview transcripts were analyzed with the assistance of the Atlas.ti software for code and theme identification. Influences of hotel housekeeping work on hypertension management arose both at the individual and system levels. Factors at the individual level included co-worker dynamics and maintenance of transmigrant life. Factors at the system level included supervisory support, workload, work pace, and work hiring practices. No positive influences were reported for workload and hiring practices. Workplace interventions may be beneficial for effective hypertension management among hotel housekeepers. These work influences must be considered when determining effective methods for hypertension management among hotel housekeepers. © 2013 Wiley Periodicals, Inc.

Hotel Housekeeping Work Influences on Hypertension Management

PubMed Central

Sanon, Marie-Anne

2013-01-01

Background Characteristics of hotel housekeeping work increase the risk for hypertension development. Little is known about the influences of such work on hypertension management. Methods For this qualitative study, 27 Haitian immigrant hotel housekeepers from Miami-Dade County, FL were interviewed. Interview transcripts were analyzed with the assistance of the Atlas. ti software for code and theme identification. Results Influences of hotel housekeeping work on hypertension management arose both at the individual and system levels. Factors at the individual level included co-worker dynamics and maintenance of transmigrant life. Factors at the system level included supervisory support, workload, work pace, and work hiring practices. No positive influences were reported for workload and hiring practices. Conclusions Workplace interventions may be beneficial for effective hypertension management among hotel housekeepers. These work influences must be considered when determining effective methods for hypertension management among hotel housekeepers. PMID:23775918

Region effects influence local tree species diversity.

PubMed

Ricklefs, Robert E; He, Fangliang

2016-01-19

Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

Mid-Life Career Influence

ERIC Educational Resources Information Center

Heald, James E.

1977-01-01

Events common to all people, although in differing degrees, such as physiological and technological changes at mid-life, constitute important influences on career change and development in the mid-life period. (Author)

The influence of anonymous peers on prosocial behavior

PubMed Central

Shin, Jongho

2017-01-01

Background Peer influence on students’ maladaptive behaviors has been well documented; however, the influence on positive development is less acknowledged. Purpose The purpose of this study was to examine anonymous peer influence on college students’ prosocial behavior, specifically behavior for the improvement of society (i.e., donating money or participating in social campaigns) via an experimental approach. The effects of indirect peer influence (IP) and direct peer influence (DP) on college students’ prosocial behavior were examined. Methods A total of 125 college students participated in an online survey and laboratory experiment. Self-reported helping behavior, social concern goals, and empathy were measured by the online survey. In the laboratory experiments, reading of a prosocial paragraph (IP) and confederates’ prosocial behavior (DP) were manipulated. Participation in a signature campaign and money donation for illness were observed. Furthermore, 19 participants among those who donated were asked about their reasons for participating in such prosocial behavior. Results Prosocial behavior of anonymous peers (confederates) exerts a profound influence on college students’ participation in a signature campaign and money donation, whereas the reading of a prosocial paragraph has no effect. Furthermore, no participants reported peer influence as a reason for engaging in prosocial behavior. Conclusion This finding supports and extends recent research examining the positive impacts of anonymous peers on prosocial behavior. Prosocial behavior is not only a foundational and consistent aspect of personality, as previous studies report, but is also highly malleable and unstable in response to immediate situations. PMID:29016612

The influence of anonymous peers on prosocial behavior.

PubMed

Park, Soowon; Shin, Jongho

2017-01-01

Peer influence on students' maladaptive behaviors has been well documented; however, the influence on positive development is less acknowledged. The purpose of this study was to examine anonymous peer influence on college students' prosocial behavior, specifically behavior for the improvement of society (i.e., donating money or participating in social campaigns) via an experimental approach. The effects of indirect peer influence (IP) and direct peer influence (DP) on college students' prosocial behavior were examined. A total of 125 college students participated in an online survey and laboratory experiment. Self-reported helping behavior, social concern goals, and empathy were measured by the online survey. In the laboratory experiments, reading of a prosocial paragraph (IP) and confederates' prosocial behavior (DP) were manipulated. Participation in a signature campaign and money donation for illness were observed. Furthermore, 19 participants among those who donated were asked about their reasons for participating in such prosocial behavior. Prosocial behavior of anonymous peers (confederates) exerts a profound influence on college students' participation in a signature campaign and money donation, whereas the reading of a prosocial paragraph has no effect. Furthermore, no participants reported peer influence as a reason for engaging in prosocial behavior. This finding supports and extends recent research examining the positive impacts of anonymous peers on prosocial behavior. Prosocial behavior is not only a foundational and consistent aspect of personality, as previous studies report, but is also highly malleable and unstable in response to immediate situations.

Factors influencing perceived angular velocity.

PubMed

Kaiser, M K; Calderone, J B

1991-11-01

The assumption that humans are able to perceive and process angular kinematics is critical to many structure-from-motion and optical flow models. The current studies investigate this sensitivity, and examine several factors likely to influence angular velocity perception. In particular, three factors are considered: (1) the extent to which perceived angular velocity is determined by edge transitions of surface elements, (2) the extent to which angular velocity estimates are influenced by instantaneous linear velocities of surface elements, and (3) whether element-velocity effects are related to three-dimensional (3-D) tangential velocities or to two-dimensional (2-D) image velocities. Edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities influenced perceived angular velocity; this bias was related to 2-D image velocity rather than 3-D tangential velocity. Despite these biases, however, judgments were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter was surprisingly good, for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

A Review of Primary and Secondary Influences on Sport Expertise

ERIC Educational Resources Information Center

Baker, Joseph; Horton, Sean

2004-01-01

Sport scientists have examined numerous factors influencing the acquisition and manifestation of high levels of performance. These factors can be divided into variables having a primary influence on expertise and variables that have a secondary influence through their interaction with other variables. Primary influences on expertise include…

Nonmetropolitan Migration: The Influence of Neglected Variables.

ERIC Educational Resources Information Center

Cook, Annabel Kirschner

1987-01-01

Compares influence of employment growth/diversity, commuting, retirement migration, income, unemployment, age structure, and adjacency with influence of nonfarm self-employment and percentage of labor force that is female on recent declines in nonmetropolitan growth rates. Suggests last two variables are more important determinants of…

Leading God's People: Perceptions of Influence Among African-American Pastors.

PubMed

Harmon, Brook E; Strayhorn, Shaila; Webb, Benjamin L; Hébert, James R

2018-01-31

Religious leaders, particularly African-American pastors, are believed to play a key role in addressing health disparities. Despite the role African-American pastors may play in improving health, there is limited research on pastoral influence. The purpose of this study was to examine African-American pastors' perceptions of their influence in their churches and communities. In-depth interviews were conducted with 30 African-American pastors and analyzed using a grounded theory approach. Three themes emerged: the historical role of the church; influence as contextual, with pastors using comparisons with other pastors to describe their ability to be influential; and a reciprocal relationship existing such that pastors are influenced by factors such as God and their community while these factors also aid them in influencing others. A conceptual model of pastoral influence was created using data from this study and others to highlight factors that influence pastors, potential outcomes and moderators as well as the reciprocal nature of pastoral influence.

Beyond Homophily: A Decade of Advances in Understanding Peer Influence Processes.

PubMed

Brechwald, Whitney A; Prinstein, Mitchell J

2011-03-01

This article reviews empirical and theoretical contributions to a multidisciplinary understanding of peer influence processes in adolescence over the past decade. Five themes of peer influence research from this decade were identified, including a broadening of the range of behaviors for which peer influence occurs, distinguishing the sources of influence, probing the conditions under which influence is amplified/attenuated (moderators), testing theoretically based models of peer influence processes (mechanisms), and preliminary exploration of behavioral neuroscience perspectives on peer influence. This review highlights advances in each of these areas, underscores gaps in current knowledge of peer influence processes, and outlines important challenges for future research.

Beyond Homophily: A Decade of Advances in Understanding Peer Influence Processes

PubMed Central

Brechwald, Whitney A.; Prinstein, Mitchell J.

2013-01-01

This article reviews empirical and theoretical contributions to a multidisciplinary understanding of peer influence processes in adolescence over the past decade. Five themes of peer influence research from this decade were identified, including a broadening of the range of behaviors for which peer influence occurs, distinguishing the sources of influence, probing the conditions under which influence is amplified/attenuated (moderators), testing theoretically based models of peer influence processes (mechanisms), and preliminary exploration of behavioral neuroscience perspectives on peer influence. This review highlights advances in each of these areas, underscores gaps in current knowledge of peer influence processes, and outlines important challenges for future research. PMID:23730122

Parental Education Moderates Genetic Influences on Reading Disability

PubMed Central

Friend, Angela; DeFries, John C.; Olson, Richard K.

2008-01-01

Environmental moderation of the level of genetic influence on children's reading disabilities (RD) was explored in a sample of 545 identical and fraternal twins (mean age = 11.5 years). Parents' years of education, which are correlated with a broad range of environmental factors related to reading development, were significantly related to the level of genetic influence on reading disability (t = 3.23, Prep = .99). Genetic influence was higher and environmental influence was lower among children with higher compared to children with lower parent education. We discuss the implications of these results for behavior- and molecular-genetic research, for the diagnosis and remediation of RD, and for policy in public education. PMID:19076484

Lineup Administrator Influences on Eyewitness Identification Decisions

ERIC Educational Resources Information Center

Clark, Steven E.; Marshall, Tanya E.; Rosenthal, Robert

2009-01-01

The present research examines how a lineup administrator may influence eyewitness identification decisions through different forms of influence, after providing the witness with standard, unbiased instructions. Participant-witnesses viewed a staged crime and were later shown a target-present or target-absent lineup. The lineup administrators…

Perceptions of Advertising Influence on Broadcast News.

ERIC Educational Resources Information Center

Brown, Hubert W.; Barnes, Beth E.

2001-01-01

Finds that while students (studying broadcast journalism or advertising) and practitioners (station news directors and agency media directors) were in agreement on the majority of opinion statements discussing advertising's influence on broadcast news content, except students were less bothered by advertising's influence on news content than were…

Factors that Influence Participation in Online Learning

ERIC Educational Resources Information Center

Vonderwell, Selma; Zachariah, Sajit

2005-01-01

This study explored what factors influenced learner participation in two sections of a graduate online course at a Midwestern university. Findings indicated that online learner participation and patterns of participation are influenced by the following factors: technology and interface characteristics, content area experience, student roles and…

Influencing the future of AGU

NASA Astrophysics Data System (ADS)

McPhaden, Michael; Finn, Carol; McEntee, Chris

2012-01-01

Steve Jobs, visionary cofounder of Apple, Inc., once said, “Everyone here has the sense that right now is one of those moments when we are influencing the future.” This statement aptly describes AGU at this time as the Board of Directors and the Council continue to influence the future in exciting ways by advancing our strategic plan (http://www.agu.org/about/mission.shtml). Both governing bodies held meetings in San Francisco immediately preceding the 2011 AGU Fall Meeting. The agendas for both meetings, along with the key outcomes, are posted on AGU's Web site (http://www.agu.org/about/governance/).

Factors that influence women's dispositions toward science

NASA Astrophysics Data System (ADS)

Atria, Catherine Graczyk

Females have been underrepresented in the study of science and science careers for decades although advancements have been made in closing this gender gap, the gap persists particularly in the physical sciences. Variables which influence a woman's desire to pursue and maintain a science course of study and career must be discovered. The United States lags behind other industrialized countries in the fields of science, math, and engineering. Females comprise an estimated half of the population; their potential contributions cannot be ignored or overlooked. This retrospective research study explores the personal experiences of ten women enrolled in science majors, with science related career plans. The goal of this study is to describe the factors that influence the participants' interest in science. The findings, the effect of science coursework, science teachers' personality and manner, other influential educational personnel, role models and mentors, external influences exclusive of school, parental influence, locus of control and positive attitudes toward science confirm what other researchers have found.

The benefits of social influence in optimized cultural markets.

PubMed

Abeliuk, Andrés; Berbeglia, Gerardo; Cebrian, Manuel; Van Hentenryck, Pascal

2015-01-01

Social influence has been shown to create significant unpredictability in cultural markets, providing one potential explanation why experts routinely fail at predicting commercial success of cultural products. As a result, social influence is often presented in a negative light. Here, we show the benefits of social influence for cultural markets. We present a policy that uses product quality, appeal, position bias and social influence to maximize expected profits in the market. Our computational experiments show that our profit-maximizing policy leverages social influence to produce significant performance benefits for the market, while our theoretical analysis proves that our policy outperforms in expectation any policy not displaying social signals. Our results contrast with earlier work which focused on showing the unpredictability and inequalities created by social influence. Not only do we show for the first time that, under our policy, dynamically showing consumers positive social signals increases the expected profit of the seller in cultural markets. We also show that, in reasonable settings, our profit-maximizing policy does not introduce significant unpredictability and identifies "blockbusters". Overall, these results shed new light on the nature of social influence and how it can be leveraged for the benefits of the market.

Polarity related influence maximization in signed social networks.

PubMed

Li, Dong; Xu, Zhi-Ming; Chakraborty, Nilanjan; Gupta, Anika; Sycara, Katia; Li, Sheng

2014-01-01

Influence maximization in social networks has been widely studied motivated by applications like spread of ideas or innovations in a network and viral marketing of products. Current studies focus almost exclusively on unsigned social networks containing only positive relationships (e.g. friend or trust) between users. Influence maximization in signed social networks containing both positive relationships and negative relationships (e.g. foe or distrust) between users is still a challenging problem that has not been studied. Thus, in this paper, we propose the polarity-related influence maximization (PRIM) problem which aims to find the seed node set with maximum positive influence or maximum negative influence in signed social networks. To address the PRIM problem, we first extend the standard Independent Cascade (IC) model to the signed social networks and propose a Polarity-related Independent Cascade (named IC-P) diffusion model. We prove that the influence function of the PRIM problem under the IC-P model is monotonic and submodular Thus, a greedy algorithm can be used to achieve an approximation ratio of 1-1/e for solving the PRIM problem in signed social networks. Experimental results on two signed social network datasets, Epinions and Slashdot, validate that our approximation algorithm for solving the PRIM problem outperforms state-of-the-art methods.

Polarity Related Influence Maximization in Signed Social Networks

PubMed Central

Li, Dong; Xu, Zhi-Ming; Chakraborty, Nilanjan; Gupta, Anika; Sycara, Katia; Li, Sheng

2014-01-01

Influence maximization in social networks has been widely studied motivated by applications like spread of ideas or innovations in a network and viral marketing of products. Current studies focus almost exclusively on unsigned social networks containing only positive relationships (e.g. friend or trust) between users. Influence maximization in signed social networks containing both positive relationships and negative relationships (e.g. foe or distrust) between users is still a challenging problem that has not been studied. Thus, in this paper, we propose the polarity-related influence maximization (PRIM) problem which aims to find the seed node set with maximum positive influence or maximum negative influence in signed social networks. To address the PRIM problem, we first extend the standard Independent Cascade (IC) model to the signed social networks and propose a Polarity-related Independent Cascade (named IC-P) diffusion model. We prove that the influence function of the PRIM problem under the IC-P model is monotonic and submodular Thus, a greedy algorithm can be used to achieve an approximation ratio of 1-1/e for solving the PRIM problem in signed social networks. Experimental results on two signed social network datasets, Epinions and Slashdot, validate that our approximation algorithm for solving the PRIM problem outperforms state-of-the-art methods. PMID:25061986

A Network Method of Measuring Affiliation-based Peer Influence: Assessing the Influences of Teammates’ Smoking on Adolescent Smoking

PubMed Central

Fujimoto, Kayo; Unger, Jennifer B.; Valente, Thomas W.

2011-01-01

Using a network analytic framework, this study introduces a new method to measure peer influence based on adolescents’ affiliations or two-mode social network data. Exposure based on affiliations is referred to as the “affiliation exposure model.” This study demonstrates the methodology using data on young adolescent smoking being influenced by joint participation in school-based organized sports activities with smokers. The analytic sample consisted of 1260 American adolescents from age 10 to 13 in middle schools, and the results of the longitudinal regression analyses showed that adolescents were more likely to smoke as they were increasingly exposed to teammates who smoke. This study illustrates the importance of peer influence via affiliation through team sports. PMID:22313152

Attendees' perceptions of commercial influence in noncommercially funded CME programs.

PubMed

Goldfarb, Elizabeth; Baer, Lee; Fromson, John A; Gorrindo, Tristan; Iodice, Kristin E; Birnbaum, Robert J

2012-01-01

The controversy surrounding commercial support for continuing medical education (CME) programs has led to policy changes, but data show no significant difference in perceived bias between commercial and noncommercial CME. Indeed, what attendees perceive as commercial influence is not fully understood. We sought to clarify what sources contribute to attendees' perceptions of commercial influence in non-industry-supported CME programs, and how attendees perceive that this influence manifests itself on both speaker and program levels. Evaluation forms were received from 1 544 attendees at 14 live noncommercially supported CME programs in 2006, 2007, and 2010. Attendees rated perceived commercial influence for each lecture and the entire program. Using open-ended and "check all that apply'' questions, participants specified perceived sources and manifestations of commercial influence. Attendees rating individual lectures but not the entire program as commercially influenced accounted for 59.9% of those who identified bias. The most frequently endorsed source of commercial influence was individual speakers' funding, and the most listed manifestations were speakers' mentions of pharmaceuticals and expressions of personal opinions. Rating the entire program commercially influenced correlated with whether attendees considered the funding of referenced research a source of influence. CME attendees consider a broad spectrum of factors when reporting commercial influence. Evaluation forms should include bias questions per lecture as well as items to clarify perceived sources and manifestations of commercial influence. Copyright © 2012 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on CME, Association for Hospital Medical Education.

Influence Strategies in Same-Sex and Opposite-Sex Friendships.

ERIC Educational Resources Information Center

Madden, Margaret E.; And Others

Some writers have suggested that males and females differ not only in influencibility, but also in the strategies which they use to influence others. Although general sex differences in friendships may affect influence strategies, there is little research comparing males' and females' friendships. To explore differences between same- and…

Paternal Involvement with Children: The Influence of Gender Ideologies

ERIC Educational Resources Information Center

Bulanda, Ronald E.

2004-01-01

Although prior social science research has established the ability of gender ideologies to influence the domestic division of labor, it has neglected to disentangle their potentially unique influence on paternal involvement with children. Past research examining the influence of gender ideology on parenting behaviors does not acknowledge potential…

Locus of Peer Influence: Social Crowd and Best Friend.

ERIC Educational Resources Information Center

Urberg, Kathryn A.

1992-01-01

The relative influence of best friends and social crowds of 324 older adolescents (eleventh graders) on cigarette smoking was examined to determine influences as a function of sex, conformity, and friendship mutuality. Best friends, rather than social crowd, appeared to be the major influence in this group. (SLD)

Anticipated Influences on Sexual Decision-Making for First Intercourse.

ERIC Educational Resources Information Center

Christopher, F. Scott; Cate, Rodney M.

1985-01-01

Examined factors that 195 college students who were virgins perceived would influence them in deciding to engage in first intercourse. Three anticipated influence factors emerged: a physical arousal factor, a relationship factor, and a circumstance factor. Males and females differed on anticipated influence of the relationship factor. (NRB)

The Influence of Alcohol Advertising on Students' Drinking Behaviors.

ERIC Educational Resources Information Center

Pedersen, Peggy J.

2002-01-01

Examines the perceived influence of alcohol advertising in a daily campus newspaper on the drinking behaviors of students. Findings indicated that college students do perceive that their drinking patterns are influenced by alcohol promotions in the campus newspaper and, furthermore, that self-identified binge drinkers were influenced significantly…

7 CFR 1205.337 - Influencing governmental action.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Influencing governmental action. 1205.337 Section... RESEARCH AND PROMOTION Cotton Research and Promotion Order Expenses and Assessments § 1205.337 Influencing governmental action. No funds collected by the Board under this subpart shall in any manner be used for the...

7 CFR 1210.362 - Influencing government action.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 10 2011-01-01 2011-01-01 false Influencing government action. 1210.362 Section 1210... RESEARCH AND PROMOTION PLAN Watermelon Research and Promotion Plan Miscellaneous § 1210.362 Influencing government action. No funds received by the Board under this Plan shall in any manner be used for the purpose...

7 CFR 1205.337 - Influencing governmental action.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 10 2011-01-01 2011-01-01 false Influencing governmental action. 1205.337 Section... RESEARCH AND PROMOTION Cotton Research and Promotion Order Expenses and Assessments § 1205.337 Influencing governmental action. No funds collected by the Board under this subpart shall in any manner be used for the...

7 CFR 1210.362 - Influencing government action.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Influencing government action. 1210.362 Section 1210... RESEARCH AND PROMOTION PLAN Watermelon Research and Promotion Plan Miscellaneous § 1210.362 Influencing government action. No funds received by the Board under this Plan shall in any manner be used for the purpose...

7 CFR 1250.351 - Influencing governmental action.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 10 2011-01-01 2011-01-01 false Influencing governmental action. 1250.351 Section... RESEARCH AND PROMOTION Egg Research and Promotion Order Expenses and Assessments § 1250.351 Influencing governmental action. No funds collected by the Board under this subpart shall in any manner be used for the...

7 CFR 1250.351 - Influencing governmental action.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Influencing governmental action. 1250.351 Section... RESEARCH AND PROMOTION Egg Research and Promotion Order Expenses and Assessments § 1250.351 Influencing governmental action. No funds collected by the Board under this subpart shall in any manner be used for the...

Factors Influencing Title VII Bilingual Program Institutionalization.

ERIC Educational Resources Information Center

Lewis, Gerald R.; And Others

1985-01-01

This study of the primary restraining and driving forces that influence Title VII bilingual education programs found the external environment, the local community, to be the main factor influencing institutionalization and self-renewal. The internal environment--the local school, and the local school's organization or central office, school board,…

Genetic and Environmental Influences on Adolescent Attachment

ERIC Educational Resources Information Center

Fearon, Pasco; Shmueli-Goetz, Yael; Viding, Essi; Fonagy, Peter; Plomin, Robert

2014-01-01

Background: Twin studies consistently point to limited genetic influence on attachment security in the infancy period, but no study has examined whether this remains the case in later development. This study presents the findings from a twin study examining the relative importance of genetic and environmental influences on attachment in…

The Influence of Culture on Teacher Commitment

ERIC Educational Resources Information Center

Abd Razak, Nordin; Darmawan, I. Gusti Ngurah; Keeves, John P.

2010-01-01

Culture is believed to be an important factor that influences various aspects of human life, such as behaviour, thinking, perceptions and attitudes. This article examines the similarities and differences in the influence of culture on teacher commitment in three types of Malaysian primary schools. Since commitment to teaching has rarely been…

The Neural Basis of Social Influence in a Dictator Decision.

PubMed

Wei, Zhenyu; Zhao, Zhiying; Zheng, Yong

2017-01-01

Humans tend to reduce inequitable distributions. Previous neuroimaging studies have shown that inequitable decisions are related to brain regions that associated with negative emotion and signaling conflict. In the highly complex human social environment, our opinions and behaviors can be affected by social information. In current study, we used a modified dictator game to investigate the effect of social influence on making an equitable decision. We found that the choices of participants in present task was influenced by the choices of peers. However, participants' decisions were influenced by equitable rather than inequitable group choices. fMRI results showed that brain regions that related to norm violation and social conflict were related to the inequitable social influence. The neural responses in the dorsomedial prefrontal cortex, rostral cingulate zone, and insula predicted subsequent conforming behavior in individuals. Additionally, psychophysiological interaction analysis revealed that the interconnectivity between the dorsal striatum and insula was elevated in advantageous inequity influence versus no-social influence conditions. We found decreased functional connectivity between the medial prefrontal cortex and insula, supplementary motor area, posterior cingulate gyrus and dorsal anterior cingulate cortex in the disadvantageous inequity influence versus no-social influence conditions. This suggests that a disadvantageous inequity influence may decrease the functional connectivity among brain regions that are related to reward processes. Thus, the neural mechanisms underlying social influence in an equitable decision may be similar to those implicated in social norms and reward processing.

The Neural Basis of Social Influence in a Dictator Decision

PubMed Central

Wei, Zhenyu; Zhao, Zhiying; Zheng, Yong

2017-01-01

Humans tend to reduce inequitable distributions. Previous neuroimaging studies have shown that inequitable decisions are related to brain regions that associated with negative emotion and signaling conflict. In the highly complex human social environment, our opinions and behaviors can be affected by social information. In current study, we used a modified dictator game to investigate the effect of social influence on making an equitable decision. We found that the choices of participants in present task was influenced by the choices of peers. However, participants’ decisions were influenced by equitable rather than inequitable group choices. fMRI results showed that brain regions that related to norm violation and social conflict were related to the inequitable social influence. The neural responses in the dorsomedial prefrontal cortex, rostral cingulate zone, and insula predicted subsequent conforming behavior in individuals. Additionally, psychophysiological interaction analysis revealed that the interconnectivity between the dorsal striatum and insula was elevated in advantageous inequity influence versus no-social influence conditions. We found decreased functional connectivity between the medial prefrontal cortex and insula, supplementary motor area, posterior cingulate gyrus and dorsal anterior cingulate cortex in the disadvantageous inequity influence versus no-social influence conditions. This suggests that a disadvantageous inequity influence may decrease the functional connectivity among brain regions that are related to reward processes. Thus, the neural mechanisms underlying social influence in an equitable decision may be similar to those implicated in social norms and reward processing. PMID:29375412

Acoustic Features Influence Musical Choices Across Multiple Genres.

PubMed

Barone, Michael D; Bansal, Jotthi; Woolhouse, Matthew H

2017-01-01

Based on a large behavioral dataset of music downloads, two analyses investigate whether the acoustic features of listeners' preferred musical genres influence their choice of tracks within non-preferred, secondary musical styles. Analysis 1 identifies feature distributions for pairs of genre-defined subgroups that are distinct. Using correlation analysis, these distributions are used to test the degree of similarity between subgroups' main genres and the other music within their download collections. Analysis 2 explores the issue of main-to-secondary genre influence through the production of 10 feature-influence matrices, one per acoustic feature, in which cell values indicate the percentage change in features for genres and subgroups compared to overall population averages. In total, 10 acoustic features and 10 genre-defined subgroups are explored within the two analyses. Results strongly indicate that the acoustic features of people's main genres influence the tracks they download within non-preferred, secondary musical styles. The nature of this influence and its possible actuating mechanisms are discussed with respect to research on musical preference, personality, and statistical learning.

Acoustic Features Influence Musical Choices Across Multiple Genres

PubMed Central

Barone, Michael D.; Bansal, Jotthi; Woolhouse, Matthew H.

2017-01-01

Based on a large behavioral dataset of music downloads, two analyses investigate whether the acoustic features of listeners' preferred musical genres influence their choice of tracks within non-preferred, secondary musical styles. Analysis 1 identifies feature distributions for pairs of genre-defined subgroups that are distinct. Using correlation analysis, these distributions are used to test the degree of similarity between subgroups' main genres and the other music within their download collections. Analysis 2 explores the issue of main-to-secondary genre influence through the production of 10 feature-influence matrices, one per acoustic feature, in which cell values indicate the percentage change in features for genres and subgroups compared to overall population averages. In total, 10 acoustic features and 10 genre-defined subgroups are explored within the two analyses. Results strongly indicate that the acoustic features of people's main genres influence the tracks they download within non-preferred, secondary musical styles. The nature of this influence and its possible actuating mechanisms are discussed with respect to research on musical preference, personality, and statistical learning. PMID:28725200

Influence of friends on children's physical activity: a review.

PubMed

Maturo, Claire C; Cunningham, Solveig A

2013-07-01

We examined evidence for friendship influences on children's physical activity (PA) through systematic searches of online databases in May 2012. We identified 106 studies (25 qualitative) published in English since 2000 that analyzed indicators of friendship influences (e.g., communication about PA, friends' PA, and PA with friends) among persons younger than 19 years. Children's PA was positively associated with encouragement from friends (43 of 55 studies indicating a positive relationship), friends' own PA (30/35), and engagement with friends in PA (9/10). These findings are consistent with friends influencing PA, but most studies did not isolate influence from other factors that could explain similarity. Understanding friendship influences in childhood can facilitate the promotion of lifelong healthy habits. PA with friends should be considered in health promotion programs.

Spared unconscious influences of spatial memory in diencephalic amnesia

PubMed Central

Antonides, Rémy; Wester, Arie J.; Kessels, Roy P. C.

2008-01-01

Spatial memory is crucial to our daily lives and in part strongly depends on automatic, implicit memory processes. This study investigates the neurocognitive basis of conscious and unconscious influences of object–location memory in amnesic patients with Korsakoff’s syndrome (N = 23) and healthy controls (N = 18) using a process-dissociation procedure in a computerized spatial memory task. As expected, the patients performed substantially worse on the conscious memory measures but showed even slightly stronger effects of unconscious influences than the controls. Moreover, a delayed test administered after 1 week revealed a strong decline in conscious influences in the patients, while unconscious influences were not affected. The presented results suggest that conscious and unconscious influences of spatial memory can be clearly dissociated in Korsakoff’s syndrome. PMID:18560813

The Influence of Sleep Disorders on Voice Quality.

PubMed

Rocha, Bruna Rainho; Behlau, Mara

2017-09-19

To verify the influence of sleep quality on the voice. Descriptive and analytical cross-sectional study. Data were collected by an online or printed survey divided in three parts: (1) demographic data and vocal health aspects; (2) self-assessment of sleep and vocal quality, and the influence that sleep has on voice; and (3) sleep and voice self-assessment inventories-the Epworth Sleepiness Scale (ESS), the Pittsburgh Sleep Quality Index (PSQI), and the Voice Handicap Index reduced version (VHI-10). A total of 862 people were included (493 women, 369 men), with a mean age of 32 years old (maximum age of 79 and minimum age of 18 years old). The perception of the influence that sleep has on voice showed a difference (P < 0.050) between measures of sleep quality and vocal self-assessment. There were higher scores on the ESS, PSQI, and VHI-10 protocols if sleep and vocal self-assessment were poor. The results indicate that the greater the effect that sleep has on voice, the greater the perceived voice handicap. The aspects that influence a voice handicap are vocal self-assessment, ESS total score, and self-assessment of the influence that sleep has on voice. The absence of daytime sleepiness is a protective factor (odds ratio [OR] > 1) against perceived voice handicap; the presence of daytime sleepiness is a damaging factor (OR < 1). Sleep quality influences voice. Perceived poor sleep quality is related to perceived poor vocal quality. Individuals with a voice handicap observe a greater influence of sleep on voice than those without. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Gender Influences on Parent-Child Science Problem-Solving Behaviors

ERIC Educational Resources Information Center

Short-Meyerson, Katherine; Sandrin, Susannah; Edwards, Chris

2016-01-01

Gender is a critical social factor influencing how children view the world from very early childhood. Additionally, during the early elementary years, parents can have a significant influence on their child's behaviors and dispositions in fields such as science. This study examined the influence of parent gender and child gender on 2nd- and…

Parental Influence and Involvement on Reading Achievement.

ERIC Educational Resources Information Center

Nebor, Jon N.

A review of the research on the effects of parental influence and parental involvement on children's reading achievement indicates that when parents take an active and positive part in their child's education the results often turn out well for the student. Parental influence is defined as any opinion, attitude, or action (other than direct…

Origin of Peer Influence in Social Networks

NASA Astrophysics Data System (ADS)

Pinheiro, Flávio L.; Santos, Marta D.; Santos, Francisco C.; Pacheco, Jorge M.

2014-03-01

Social networks pervade our everyday lives: we interact, influence, and are influenced by our friends and acquaintances. With the advent of the World Wide Web, large amounts of data on social networks have become available, allowing the quantitative analysis of the distribution of information on them, including behavioral traits and fads. Recent studies of correlations among members of a social network, who exhibit the same trait, have shown that individuals influence not only their direct contacts but also friends' friends, up to a network distance extending beyond their closest peers. Here, we show how such patterns of correlations between peers emerge in networked populations. We use standard models (yet reflecting intrinsically different mechanisms) of information spreading to argue that empirically observed patterns of correlation among peers emerge naturally from a wide range of dynamics, being essentially independent of the type of information, on how it spreads, and even on the class of underlying network that interconnects individuals. Finally, we show that the sparser and clustered the network, the more far reaching the influence of each individual will be.

Influence Function Learning in Information Diffusion Networks.

PubMed

Du, Nan; Liang, Yingyu; Balcan, Maria-Florina; Song, Le

2014-06-01

Can we learn the influence of a set of people in a social network from cascades of information diffusion? This question is often addressed by a two-stage approach: first learn a diffusion model, and then calculate the influence based on the learned model. Thus, the success of this approach relies heavily on the correctness of the diffusion model which is hard to verify for real world data. In this paper, we exploit the insight that the influence functions in many diffusion models are coverage functions, and propose a novel parameterization of such functions using a convex combination of random basis functions. Moreover, we propose an efficient maximum likelihood based algorithm to learn such functions directly from cascade data, and hence bypass the need to specify a particular diffusion model in advance. We provide both theoretical and empirical analysis for our approach, showing that the proposed approach can provably learn the influence function with low sample complexity, be robust to the unknown diffusion models, and significantly outperform existing approaches in both synthetic and real world data.

Influence Function Learning in Information Diffusion Networks

PubMed Central

Du, Nan; Liang, Yingyu; Balcan, Maria-Florina; Song, Le

2015-01-01

Can we learn the influence of a set of people in a social network from cascades of information diffusion? This question is often addressed by a two-stage approach: first learn a diffusion model, and then calculate the influence based on the learned model. Thus, the success of this approach relies heavily on the correctness of the diffusion model which is hard to verify for real world data. In this paper, we exploit the insight that the influence functions in many diffusion models are coverage functions, and propose a novel parameterization of such functions using a convex combination of random basis functions. Moreover, we propose an efficient maximum likelihood based algorithm to learn such functions directly from cascade data, and hence bypass the need to specify a particular diffusion model in advance. We provide both theoretical and empirical analysis for our approach, showing that the proposed approach can provably learn the influence function with low sample complexity, be robust to the unknown diffusion models, and significantly outperform existing approaches in both synthetic and real world data. PMID:25973445

Directed dynamical influence is more detectable with noise

PubMed Central

Jiang, Jun-Jie; Huang, Zi-Gang; Huang, Liang; Liu, Huan; Lai, Ying-Cheng

2016-01-01

Successful identification of directed dynamical influence in complex systems is relevant to significant problems of current interest. Traditional methods based on Granger causality and transfer entropy have issues such as difficulty with nonlinearity and large data requirement. Recently a framework based on nonlinear dynamical analysis was proposed to overcome these difficulties. We find, surprisingly, that noise can counterintuitively enhance the detectability of directed dynamical influence. In fact, intentionally injecting a proper amount of asymmetric noise into the available time series has the unexpected benefit of dramatically increasing confidence in ascertaining the directed dynamical influence in the underlying system. This result is established based on both real data and model time series from nonlinear ecosystems. We develop a physical understanding of the beneficial role of noise in enhancing detection of directed dynamical influence. PMID:27066763

Directed dynamical influence is more detectable with noise.

PubMed

Jiang, Jun-Jie; Huang, Zi-Gang; Huang, Liang; Liu, Huan; Lai, Ying-Cheng

2016-04-12

Successful identification of directed dynamical influence in complex systems is relevant to significant problems of current interest. Traditional methods based on Granger causality and transfer entropy have issues such as difficulty with nonlinearity and large data requirement. Recently a framework based on nonlinear dynamical analysis was proposed to overcome these difficulties. We find, surprisingly, that noise can counterintuitively enhance the detectability of directed dynamical influence. In fact, intentionally injecting a proper amount of asymmetric noise into the available time series has the unexpected benefit of dramatically increasing confidence in ascertaining the directed dynamical influence in the underlying system. This result is established based on both real data and model time series from nonlinear ecosystems. We develop a physical understanding of the beneficial role of noise in enhancing detection of directed dynamical influence.

The Power of Influence: School Nurse Stories.

PubMed

Mazyck, Donna; Cellucci, Margaret; Largent, Piper

2015-07-01

School nurses have influence, and this influence is ignited with school nurse stories. School nurses must tell school staff, leaders, families, and students what they do to help students access their education. School boards, city councils, and legislators need to know the knowledge, skills, and judgment school nurses use daily. NASN understands that school nurses benefit from a "how to" kit and has developed tools to empower school nurses in advocating for their important role in supporting the health and learning of students. This article provides an overview this newly developed electronic toolkit while at the same time reinforcing the power of influence when sharing your stories. © 2015 The Author(s).

Modeling wilderness campsites: Factors that influence amount of impact

Treesearch

David N. Cole

1991-01-01

A standard campsite model is proposed and then manipulated to examine the influence of individual variables on amount of vegetation loss. Amount of impact is influenced by amount of use, vegetation fragility, vegetation density, and the degree to which activities are concentrated spatially on the site. Degree of concentration also influences the importance of the other...

Influence Diagram Use With Respect to Technology Planning and Investment

NASA Technical Reports Server (NTRS)

Levack, Daniel J. H.; DeHoff, Bryan; Rhodes, Russel E.

2009-01-01

Influence diagrams are relatively simple, but powerful, tools for assessing the impact of choices or resource allocations on goals or requirements. They are very general and can be used on a wide range of problems. They can be used for any problem that has defined goals, a set of factors that influence the goals or the other factors, and a set of inputs. Influence diagrams show the relationship among a set of results and the attributes that influence them and the inputs that influence the attributes. If the results are goals or requirements of a program, then the influence diagram can be used to examine how the requirements are affected by changes to technology investment. This paper uses an example to show how to construct and interpret influence diagrams, how to assign weights to the inputs and attributes, how to assign weights to the transfer functions (influences), and how to calculate the resulting influences of the inputs on the results. A study is also presented as an example of how using influence diagrams can help in technology planning and investment. The Space Propulsion Synergy Team (SPST) used this technique to examine the impact of R&D spending on the Life Cycle Cost (LCC) of a space transportation system. The question addressed was the effect on the recurring and the non-recurring portions of LCC of the proportion of R&D resources spent to impact technology objectives versus the proportion spent to impact operational dependability objectives. The goals, attributes, and the inputs were established. All of the linkages (influences) were determined. The weighting of each of the attributes and each of the linkages was determined. Finally the inputs were varied and the impacts on the LCC determined and are presented. The paper discusses how each of these was accomplished both for credibility and as an example for future studies using influence diagrams for technology planning and investment planning.

Influences of geomorphology and geology on alpine treeline in the American West - More important than climatic influences?

USGS Publications Warehouse

Butler, D.R.; Malanson, G.P.; Walsh, S.J.; Fagre, D.B.

2007-01-01

The spatial distribution and pattern of alpine treeline in the American West reflect the overarching influences of geological history, lithology and structure, and geomorphic processes and landforms, and geologic and geomorphic factors—both forms and processes—can control the spatiotemporal response of the ecotone to climate change. These influences occur at spatial scales ranging from the continental scale to fine scale processes and landforms at the slope scale. Past geomorphic influences, particularly Pleistocene glaciation, have also left their impact on treeline, and treelines across the west are still adjusting to post-Pleistocene conditions within Pleistocene-created landforms. Current fine scale processes include solifluction and changes on relict solifluction and digging by animals. These processes should be examined in detail in future studies to facilitate a better understanding of where individual tree seedlings become established as a primary response of the ecotone to climate change.

The Influence of Notches Under Static Stress

NASA Technical Reports Server (NTRS)

Matthaes, K

1938-01-01

From the described experiments it is seen that notches are a potential source of strength decrease even under static stress, which the designer must take into consideration. Section I is a general treatment of notch influence under the various types of stresses. Section II treats the influence of notches in thin sheet as is used in airplane construction.

American Influence on Okinawan Culture before 1972.

ERIC Educational Resources Information Center

Trafton, Terry

The Ryukyu Islands form a chain stretching from the southernmost point of mainland Japan to the northern tip of Taiwan. The largest and most important of these islands is Okinawa. This paper documents the influence of other nations and cultures upon the Okinawan culture, and focuses upon U.S. cultural influence. In the mid-nineteenth century,…

Influence of musical groove on postural sway.

PubMed

Ross, Jessica M; Warlaumont, Anne S; Abney, Drew H; Rigoli, Lillian M; Balasubramaniam, Ramesh

2016-03-01

Timescales of postural fluctuation reflect underlying neuromuscular processes in balance control that are influenced by sensory information and the performance of concurrent cognitive and motor tasks. An open question is how postural fluctuations entrain to complex environmental rhythms, such as in music, which also vary on multiple timescales. Musical groove describes the property of music that encourages auditory-motor synchronization and is used to study voluntary motor entrainment to rhythmic sounds. The influence of groove on balance control mechanisms remains unexplored. We recorded fluctuations in center of pressure (CoP) of standing participants (N = 40) listening to low and high groove music and during quiet stance. We found an effect of musical groove on radial sway variability, with the least amount of variability in the high groove condition. In addition, we observed that groove influenced postural sway entrainment at various temporal scales. For example, with increasing levels of groove, we observed more entrainment to shorter, local timescale rhythmic musical occurrences. In contrast, we observed more entrainment to longer, global timescale features of the music, such as periodicity, with decreasing levels of groove. Finally, musical experience influenced the amount of postural variability and entrainment at local and global timescales. We conclude that groove in music and musical experience can influence the neural mechanisms that govern balance control, and discuss implications of our findings in terms of multiscale sensorimotor coupling. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Sensorimotor influences on speech perception in infancy.

PubMed

Bruderer, Alison G; Danielson, D Kyle; Kandhadai, Padmapriya; Werker, Janet F

2015-11-03

The influence of speech production on speech perception is well established in adults. However, because adults have a long history of both perceiving and producing speech, the extent to which the perception-production linkage is due to experience is unknown. We addressed this issue by asking whether articulatory configurations can influence infants' speech perception performance. To eliminate influences from specific linguistic experience, we studied preverbal, 6-mo-old infants and tested the discrimination of a nonnative, and hence never-before-experienced, speech sound distinction. In three experimental studies, we used teething toys to control the position and movement of the tongue tip while the infants listened to the speech sounds. Using ultrasound imaging technology, we verified that the teething toys consistently and effectively constrained the movement and positioning of infants' tongues. With a looking-time procedure, we found that temporarily restraining infants' articulators impeded their discrimination of a nonnative consonant contrast but only when the relevant articulator was selectively restrained to prevent the movements associated with producing those sounds. Our results provide striking evidence that even before infants speak their first words and without specific listening experience, sensorimotor information from the articulators influences speech perception. These results transform theories of speech perception by suggesting that even at the initial stages of development, oral-motor movements influence speech sound discrimination. Moreover, an experimentally induced "impairment" in articulator movement can compromise speech perception performance, raising the question of whether long-term oral-motor impairments may impact perceptual development.

Factors potentially influencing aminoglycoside use and expenditure

DOE Office of Scientific and Technical Information (OSTI.GOV)

DiPiro, J.T.; Kilsdonk, G.F.; Amerson, A.B.

1982-07-01

Factors that may have influenced aminoglycoside use and expenditure in one hospital were examined. Factors that were evaluated as to their influence on aminoglycoside-use patterns were: (1) formulary status; (2) bacterial susceptibility patterns; (3) identified or perceived differences in toxicity; (4) changes in patient population; (5) price paid by the hospital for aminoglycosides; (6) distribution of newsletters or memoranda; (7) advertising and detailing; and (8) pharmacy policies. For FY 1976-77 to 1979-80, the largest proportion of aminoglycoside expense was for gentamicin. During FY 1980-81, the expenditure for gentamicin decreased and tobramycin accounted for the largest proportion of total expenditure. Monthlymore » gentamicin use decreased 20% during FY 1980-81 from the previous year. Tobramycin use increased from January 1979 to November 1980 and decreased from December 1980 to June 1981. Kanamycin use and amikacin use were fairly constant during the study period. Based on temporal relationships, the following factors appeared to influence aminoglycoside use and expenditure: (1) a study conducted at the institution from June 1977 to June 1979 comparing gentamicin and tobramycin nephrotoxicity; (2) a comparative nephrotoxicity study published in a widely circulated medical journal in May 1980; and (3) an intramural newsletter and memorandum distributed in March 1981 encouraging selective aminoglycoside use. The identification of factors that potentially influenced aminoglycoside use can be used to anticipate the future impact of similar events and to devise strategies to influence antimicrobial use.« less

The Soil Microbiome Influences Grapevine-Associated Microbiota

PubMed Central

Zarraonaindia, Iratxe; Owens, Sarah M.; Weisenhorn, Pamela; West, Kristin; Hampton-Marcell, Jarrad; Lax, Simon; Bokulich, Nicholas A.; Mills, David A.; Martin, Gilles; Taghavi, Safiyh; van der Lelie, Daniel

2015-01-01

ABSTRACT Grapevine is a well-studied, economically relevant crop, whose associated bacteria could influence its organoleptic properties. In this study, the spatial and temporal dynamics of the bacterial communities associated with grapevine organs (leaves, flowers, grapes, and roots) and soils were characterized over two growing seasons to determine the influence of vine cultivar, edaphic parameters, vine developmental stage (dormancy, flowering, preharvest), and vineyard. Belowground bacterial communities differed significantly from those aboveground, and yet the communities associated with leaves, flowers, and grapes shared a greater proportion of taxa with soil communities than with each other, suggesting that soil may serve as a bacterial reservoir. A subset of soil microorganisms, including root colonizers significantly enriched in plant growth-promoting bacteria and related functional genes, were selected by the grapevine. In addition to plant selective pressure, the structure of soil and root microbiota was significantly influenced by soil pH and C:N ratio, and changes in leaf- and grape-associated microbiota were correlated with soil carbon and showed interannual variation even at small spatial scales. Diazotrophic bacteria, e.g., Rhizobiaceae and Bradyrhizobium spp., were significantly more abundant in soil samples and root samples of specific vineyards. Vine-associated microbial assemblages were influenced by myriad factors that shape their composition and structure, but the majority of organ-associated taxa originated in the soil, and their distribution reflected the influence of highly localized biogeographic factors and vineyard management. PMID:25805735

The soil microbiome influences grapevine-associated microbiota

DOE PAGES

Zarraonaindia, Iratxe; Owens, Sarah M.; Weisenhorn, Pamela; ...

2015-03-24

Grapevine is a well-studied, economically relevant crop, whose associated bacteria could influence its organoleptic properties. In this study, the spatial and temporal dynamics of the bacterial communities associated with grapevine organs (leaves, flowers, grapes, and roots) and soils were characterized over two growing seasons to determine the influence of vine cultivar, edaphic parameters, vine developmental stage (dormancy, flowering, preharvest), and vineyard. Belowground bacterial communities differed significantly from those aboveground, and yet the communities associated with leaves, flowers, and grapes shared a greater proportion of taxa with soil communities than with each other, suggesting that soil may serve as a bacterialmore » reservoir. A subset of soil microorganisms, including root colonizers significantly enriched in plant growth-promoting bacteria and related functional genes, were selected by the grapevine. In addition to plant selective pressure, the structure of soil and root microbiota was significantly influenced by soil pH and C:N ratio, and changes in leaf- and grape-associated microbiota were correlated with soil carbon and showed interannual variation even at small spatial scales. Diazotrophic bacteria, e.g., Rhizobiaceae and Bradyrhizobium spp., were significantly more abundant in soil samples and root samples of specific vineyards. Vine-associated microbial assemblages were influenced by myriad factors that shape their composition and structure, but the majority of organ-associated taxa originated in the soil, and their distribution reflected the influence of highly localized biogeographic factors and vineyard management.« less

Attitude change: persuasion and social influence.

PubMed

Wood, W

2000-01-01

This chapter reviews empirical and theoretical developments in research on social influence and message-based persuasion. The review emphasizes research published during the period from 1996-1998. Across these literatures, three central motives have been identified that generate attitude change and resistance. These involve concerns with the self, with others and the rewards/punishments they can provide, and with a valid understanding of reality. The motives have implications for information processing and for attitude change in public and private contexts. Motives in persuasion also have been investigated in research on attitude functions and cognitive dissonance theory. In addition, the chapter reviews the relatively unique aspects of each literature: In persuasion, it considers the cognitive and affective mechanisms underlying attitude change, especially dual-mode processing models, recipients' affective reactions, and biased processing. In social influence, the chapter considers how attitudes are embedded in social relations, including social identity theory and majority/minority group influence.

Quantifying the effects of social influence

PubMed Central

Mavrodiev, Pavlin; Tessone, Claudio J.; Schweitzer, Frank

2013-01-01

How do humans respond to indirect social influence when making decisions? We analysed an experiment where subjects had to guess the answer to factual questions, having only aggregated information about the answers of others. While the response of humans to aggregated information is a widely observed phenomenon, it has not been investigated quantitatively, in a controlled setting. We found that the adjustment of individual guesses depends linearly on the distance to the mean of all guesses. This is a remarkable, and yet surprisingly simple regularity. It holds across all questions analysed, even though the correct answers differ by several orders of magnitude. Our finding supports the assumption that individual diversity does not affect the response to indirect social influence. We argue that the nature of the response crucially changes with the level of information aggregation. This insight contributes to the empirical foundation of models for collective decisions under social influence. PMID:23449043

Dynamical networks of influence in small group discussions.

PubMed

Moussaïd, Mehdi; Noriega Campero, Alejandro; Almaatouq, Abdullah

2018-01-01

In many domains of life, business and management, numerous problems are addressed by small groups of individuals engaged in face-to-face discussions. While research in social psychology has a long history of studying the determinants of small group performances, the internal dynamics that govern a group discussion are not yet well understood. Here, we rely on computational methods based on network analyses and opinion dynamics to describe how individuals influence each other during a group discussion. We consider the situation in which a small group of three individuals engages in a discussion to solve an estimation task. We propose a model describing how group members gradually influence each other and revise their judgments over the course of the discussion. The main component of the model is an influence network-a weighted, directed graph that determines the extent to which individuals influence each other during the discussion. In simulations, we first study the optimal structure of the influence network that yields the best group performances. Then, we implement a social learning process by which individuals adapt to the past performance of their peers, thereby affecting the structure of the influence network in the long run. We explore the mechanisms underlying the emergence of efficient or maladaptive networks and show that the influence network can converge towards the optimal one, but only when individuals exhibit a social discounting bias by downgrading the relative performances of their peers. Finally, we find a late-speaker effect, whereby individuals who speak later in the discussion are perceived more positively in the long run and are thus more influential. The numerous predictions of the model can serve as a basis for future experiments, and this work opens research on small group discussion to computational social sciences.

Dynamical networks of influence in small group discussions

PubMed Central

Noriega Campero, Alejandro; Almaatouq, Abdullah

2018-01-01

In many domains of life, business and management, numerous problems are addressed by small groups of individuals engaged in face-to-face discussions. While research in social psychology has a long history of studying the determinants of small group performances, the internal dynamics that govern a group discussion are not yet well understood. Here, we rely on computational methods based on network analyses and opinion dynamics to describe how individuals influence each other during a group discussion. We consider the situation in which a small group of three individuals engages in a discussion to solve an estimation task. We propose a model describing how group members gradually influence each other and revise their judgments over the course of the discussion. The main component of the model is an influence network—a weighted, directed graph that determines the extent to which individuals influence each other during the discussion. In simulations, we first study the optimal structure of the influence network that yields the best group performances. Then, we implement a social learning process by which individuals adapt to the past performance of their peers, thereby affecting the structure of the influence network in the long run. We explore the mechanisms underlying the emergence of efficient or maladaptive networks and show that the influence network can converge towards the optimal one, but only when individuals exhibit a social discounting bias by downgrading the relative performances of their peers. Finally, we find a late-speaker effect, whereby individuals who speak later in the discussion are perceived more positively in the long run and are thus more influential. The numerous predictions of the model can serve as a basis for future experiments, and this work opens research on small group discussion to computational social sciences. PMID:29338013

Reynolds number influences in aeronautics

NASA Technical Reports Server (NTRS)

Bushnell, Dennis M.; Yip, Long P.; Yao, Chung-Sheng; Lin, John C.; Lawing, Pierce L.; Batina, John T.; Hardin, Jay C.; Horvath, Thomas J.; Fenbert, James W.; Domack, Christopher S.

1993-01-01

Reynolds number, a measure of the ratio of inertia to viscous forces, is a fundamental similarity parameter for fluid flows and therefore, would be expected to have a major influence in aerodynamics and aeronautics. Reynolds number influences are generally large, but monatomic, for attached laminar (continuum) flow; however, laminar flows are easily separated, inducing even stronger, non-monatomic, Reynolds number sensitivities. Probably the strongest Reynolds number influences occur in connection with transitional flow behavior. Transition can take place over a tremendous Reynolds number range, from the order of 20 x 10(exp 3) for 2-D free shear layers up to the order of 100 x 10(exp 6) for hypersonic boundary layers. This variability in transition behavior is especially important for complex configurations where various vehicle and flow field elements can undergo transition at various Reynolds numbers, causing often surprising changes in aerodynamics characteristics over wide ranges in Reynolds number. This is further compounded by the vast parameterization associated with transition, in that any parameter which influences mean viscous flow development (e.g., pressure gradient, flow curvature, wall temperature, Mach number, sweep, roughness, flow chemistry, shock interactions, etc.), and incident disturbance fields (acoustics, vorticity, particulates, temperature spottiness, even electro static discharges) can alter transition locations to first order. The usual method of dealing with the transition problem is to trip the flow in the generally lower Reynolds number wind tunnel to simulate the flight turbulent behavior. However, this is not wholly satisfactory as it results in incorrectly scaled viscous region thicknesses and cannot be utilized at all for applications such as turbine blades and helicopter rotors, nacelles, leading edge and nose regions, and High Altitude Long Endurance and hypersonic airbreathers where the transitional flow is an innately critical

Spontaneous emergence of social influence in online systems

PubMed Central

Onnela, Jukka-Pekka; Reed-Tsochas, Felix

2010-01-01

Social influence drives both offline and online human behavior. It pervades cultural markets, and manifests itself in the adoption of scientific and technical innovations as well as the spread of social practices. Prior empirical work on the diffusion of innovations in spatial regions or social networks has largely focused on the spread of one particular technology among a subset of all potential adopters. Here we choose an online context that allows us to study social influence processes by tracking the popularity of a complete set of applications installed by the user population of a social networking site, thus capturing the behavior of all individuals who can influence each other in this context. By extending standard fluctuation scaling methods, we analyze the collective behavior induced by 100 million application installations, and show that two distinct regimes of behavior emerge in the system. Once applications cross a particular threshold of popularity, social influence processes induce highly correlated adoption behavior among the users, which propels some of the applications to extraordinary levels of popularity. Below this threshold, the collective effect of social influence appears to vanish almost entirely, in a manner that has not been observed in the offline world. Our results demonstrate that even when external signals are absent, social influence can spontaneously assume an on–off nature in a digital environment. It remains to be seen whether a similar outcome could be observed in the offline world if equivalent experimental conditions could be replicated. PMID:20937864

Factors influencing women's decisions about timing of motherhood.

PubMed

Benzies, Karen; Tough, Suzanne; Tofflemire, Karen; Frick, Corine; Faber, Alexandra; Newburn-Cook, Christine

2006-01-01

To examine the factors that influence women's decisions about the timing of motherhood from a life span perspective. Qualitative. Large Western Canadian city with a high rate of infants born to women aged 35 years and older. 45 Canadian women aged 20 to 48 years. Independence, a stable relationship, and declining fertility influenced women's decisions about the timing of motherhood. Women integrated child developmental transitions into a projected life plan as they considered the timing of motherhood. Partner readiness and family of origin influences played a lesser role. Delayed childbearing has become more socially acceptable, with subsequent negative connotations associated with younger motherhood. Parental benefits have limited influence on the timing of motherhood. Recognition by nurses of the various and complex factors that influence women's decisions about the timing of motherhood may flag the importance of pregnancy-related counseling for woman across the fertility life span. Policy decision makers must be cognizant of the need for additional high-risk obstetric and neonatal health services when societal norms encourage women to delay childbearing in favor of completing education and establishing a career. (c) 2006, AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses

Inferring Social Influence of Anti-Tobacco Mass Media Campaign.

PubMed

Zhan, Qianyi; Zhang, Jiawei; Yu, Philip S; Emery, Sherry; Xie, Junyuan

2017-07-01

Anti-tobacco mass media campaigns are designed to influence tobacco users. It has been proved that campaigns will produce users' changes in awareness, knowledge, and attitudes, and also produce meaningful behavior change of audience. Anti-smoking television advertising is the most important part in the campaign. Meanwhile, nowadays, successful online social networks are creating new media environment, however, little is known about the relation between social conversations and anti-tobacco campaigns. This paper aims to infer social influence of these campaigns, and the problem is formally referred to as the Social Influence inference of anti-Tobacco mass mEdia campaigns (Site) problem. To address the Site problem, a novel influence inference framework, TV advertising social influence estimation (Asie), is proposed based on our analysis of two real anti-tobacco campaigns. Asie divides audience attitudes toward TV ads into three distinct stages: 1) cognitive; 2) affective; and 3) conative. Audience online reactions at each of these three stages are depicted by Asie with specific probabilistic models based on the synergistic influences from both online social friends and offline TV ads. Extensive experiments demonstrate the effectiveness of Asie.

Pointwise influence matrices for functional-response regression.

PubMed

Reiss, Philip T; Huang, Lei; Wu, Pei-Shien; Chen, Huaihou; Colcombe, Stan

2017-12-01

We extend the notion of an influence or hat matrix to regression with functional responses and scalar predictors. For responses depending linearly on a set of predictors, our definition is shown to reduce to the conventional influence matrix for linear models. The pointwise degrees of freedom, the trace of the pointwise influence matrix, are shown to have an adaptivity property that motivates a two-step bivariate smoother for modeling nonlinear dependence on a single predictor. This procedure adapts to varying complexity of the nonlinear model at different locations along the function, and thereby achieves better performance than competing tensor product smoothers in an analysis of the development of white matter microstructure in the brain. © 2017, The International Biometric Society.

Social influence in childhood obesity interventions: a systematic review.

PubMed

Jalali, M S; Sharafi-Avarzaman, Z; Rahmandad, H; Ammerman, A S

2016-09-01

The objective of this study is to understand the pathways through which social influence at the family level moderates the impact of childhood obesity interventions. We conducted a systematic review of obesity interventions in which parents' behaviours are targeted to change children's obesity outcomes, because of the potential social and environmental influence of parents on the nutrition and physical activity behaviours of children. PubMed (1966-2013) and the Web of Science (1900-2013) were searched, and 32 studies satisfied our inclusion criteria. Results for existing mechanisms that moderate parents' influence on children's behaviour are discussed, and a causal pathway diagram is developed to map out social influence mechanisms that affect childhood obesity. We provide health professionals and researchers with recommendations for leveraging family-based social influence mechanisms to increase the efficacy of obesity intervention programmes. © 2016 World Obesity. © 2016 World Obesity.

Influence diagrams as oil spill decision science tools

EPA Science Inventory

Making inferences on risks to ecosystem services (ES) from ecological crises can be more reliably handled using decision science tools. Influence diagrams (IDs) are probabilistic networks that explicitly represent the decisions related to a problem and evidence of their influence...

Government influence on patient organizations.

PubMed

Van de Bovenkamp, Hester M; Trappenburg, Margo J

2011-12-01

Patient organizations increasingly play an important role in health care decision-making in Western countries. The Netherlands is one of the countries where this trend has gone furthest. In the literature some problems are identified, such as instrumental use of patient organizations by care providers, health insurers and the pharmaceutical industry. To strengthen the position of patient organizations government funding is often recommended as a solution. In this paper we analyze the ties between Dutch government and Dutch patient organizations to learn more about the effects of such a relationship between government and this part of civil society. Our study is based on official government documents and existing empirical research on patient organizations. We found that government influence on patient organizations has become quite substantial with government influencing the organizational structure of patient organizations, the activities these organizations perform and even their ideology. Financing patient organizations offers the government an important means to hold them accountable. Although the ties between patient organizations and the government enable the former to play a role that can be valued as positive by both parties, we argue that they raise problems as well which warrant a discussion on how much government influence on civil society is acceptable.

Do weather changes influence pain levels in women with fibromyalgia, and can psychosocial variables moderate these influences?

NASA Astrophysics Data System (ADS)

Smedslund, Geir; Eide, Hilde; Kristjansdottir, Ólöf Birna; Nes, Andrea Aparecida Gonçalves; Sexton, Harold; Fors, Egil A.

2014-09-01

The aim of this study was to examine the association between fibromyalgia pain and weather, and to investigate whether psychosocial factors influence this relationship. Women with chronic widespread pain/fibromyalgia ( N = 50) enrolled in a larger study, were recruited from a 4-week inpatient rehabilitation program in Norway ( 2009-2010), and reported their pain and psychological factors up to three times per day (morning, afternoon, evening) for 5 weeks. These ratings were then related to the official local weather parameters. Barometric pressure recorded simultaneously impacted pain significantly while temperature, relative humidity, and solar flux did not. No psychological variables influenced the weather-pain interaction. No weather parameter predicted change in the subsequent pain measures. The magnitude of the inverse association between pain and barometric pressure was very small, and none of the psychological variables studied influenced the association between pain and barometric pressure. All in all, the evidence for a strong weather-pain association in fibromyalgia seems limited at best.

Social Environmental Influences on the Development and Resolution of Alcohol Problems

PubMed Central

McCrady, Barbara S.; Zucker, Robert A.; Molina, Brooke S. G.; Ammon, Lyndsay; Ames, Genevieve M.; Longabaugh, Richard

2006-01-01

This article summarizes the proceedings of a symposium presented at the 2005 Annual Meeting of the Research Society on Alcoholism, Santa Barbara, California, June 25–30. The overall goal of the symposium was to consider the broad impact of the social environment on the development of and successful or unsuccessful resolution of drinking problems. The presentations addressed multiple social environmental influences including: the influence of children on parents (Dr. Zucker), the influence of peers and parents on adolescents (Dr. Molina), the influence of family members on adult drinking (Dr. McCrady), the influence of adult peers/friends (Dr. Kaskutas), and the influence of the occupational environment (Dr. Ames). Dr. Longabaugh, the symposium discussant, addressed models for understanding the relationships between social influences and drinking problems. PMID:16573588

Calculated spanwise lift distributions, influence functions, and influence coefficients for unswept wings in subsonic flow

NASA Technical Reports Server (NTRS)

Diederich, Franklin W; Zlotnick, Martin

1955-01-01

Spanwise lift distributions have been calculated for nineteen unswept wings with various aspect ratios and taper ratios and with a variety of angle-of-attack or twist distributions, including flap and aileron deflections, by means of the Weissinger method with eight control points on the semispan. Also calculated were aerodynamic influence coefficients which pertain to a certain definite set of stations along the span, and several methods are presented for calculating aerodynamic influence functions and coefficients for stations other than those stipulated. The information presented in this report can be used in the analysis of untwisted wings or wings with known twist distributions, as well as in aeroelastic calculations involving initially unknown twist distributions.

Diffusion Influenced Adsorption Kinetics.

PubMed

Miura, Toshiaki; Seki, Kazuhiko

2015-08-27

When the kinetics of adsorption is influenced by the diffusive flow of solutes, the solute concentration at the surface is influenced by the surface coverage of solutes, which is given by the Langmuir-Hinshelwood adsorption equation. The diffusion equation with the boundary condition given by the Langmuir-Hinshelwood adsorption equation leads to the nonlinear integro-differential equation for the surface coverage. In this paper, we solved the nonlinear integro-differential equation using the Grünwald-Letnikov formula developed to solve fractional kinetics. Guided by the numerical results, analytical expressions for the upper and lower bounds of the exact numerical results were obtained. The upper and lower bounds were close to the exact numerical results in the diffusion- and reaction-controlled limits, respectively. We examined the validity of the two simple analytical expressions obtained in the diffusion-controlled limit. The results were generalized to include the effect of dispersive diffusion. We also investigated the effect of molecular rearrangement of anisotropic molecules on surface coverage.

The levers of influence.

PubMed

Martin, W

1999-01-01

Physicians often determine the demand for health care services, as well as control the clinical processes aimed at improving health outcomes at the individual and population level. Given their important role in enhancing health status and improving the health care delivery system, it is critical that physician executives master the tools necessary to positively influence physician behavior. But changing behavior is far more complex than "doing it or not doing it." The Nike slogan "just do it" is motivating, but over-simplified. The roots of human change include: consciousness-raising, emotional arousal, commitment, helping relationships, self-reevaluation, reward, and environmental control. A model to effectively influence behavior is presented and includes setting clear expectations, measuring and monitoring performance, providing feedback, and rewarding and recognizing improvement. If all else fails, try discipline. This five-step approach is based on the science of human behavior and working with physicians in diverse settings, ranging from academic medical centers to small practices.

Categorization influences illusory conjunctions.

PubMed

Esterman, Michael; Prinzmetal, William; Robertson, Lynn

2004-08-01

Illusory conjunctions (ICs) provide evidence for a binding problem that must be resolved in vision. Objects that are perceptually grouped are more likely to have their features erroneously conjoined. We examined whether semantic grouping, determined by category membership (letter vs. number), also influences illusory conjunction rates. Participants were instructed to detect an "L" or a "7" among briefly presented character strings and to report its color. Despite high shape discrimination accuracy, participants often made color conjunction errors, reporting instead the color of a distractor character, "O". This distractor could be ambiguously interpreted as a letter or a number. The status of the "O" was determined by other noncolored flanker characters, which were either letters or numbers. When both the target and flankers were of the same category, participants made more ICs than when the target and flankers were of different categories. This finding demonstrates that alphanumeric categorization can precede and subsequently influence binding.

Cyberspace Operations: Influence Upon Evolving War Theory

DTIC Science & Technology

2011-03-18

St ra te gy R es ea rc h Pr oj ec t CYBERSPACE OPERATIONS: INFLUENCE UPON EVOLVING WAR THEORY BY COLONEL KRISTIN BAKER United States...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Cyberspace Operations: Influence Upon Evolving War Theory 5a. CONTRACT NUMBER... Leadership 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S

Adolescent Susceptibility to Peer Influence in Sexual Situations

PubMed Central

Widman, Laura; Choukas-Bradley, Sophia; Helms, Sarah W.; Prinstein, Mitchell J.

2016-01-01

Purpose One consistent predictor of adolescents’ engagement in sexual risk behavior is their belief that peers are engaging in similar behavior; however, not all youth are equally susceptible to these peer influence effects. Understanding individual differences in susceptibility to peer influence is critical to identifying adolescents at risk for negative health outcomes. The purpose of this project was to identify predictors of susceptibility to peer influence using a novel performance-based measure of sexual risk-taking. Methods Participants were 300 early adolescents (Mage=12.6; 53% female; 44% Caucasian) who completed 1) a pretest assessment of demographics, sexual attitudes, and hypothetical scenarios measuring the likelihood of engaging in sexual risk behavior, and 2) a subsequent experimental procedure that simulated an internet chat room in which youth believed they were communicating with peers regarding these same hypothetical scenarios. In reality, these “peers” were computer-programmed e-confederates. Changes in responses to the sexual scenarios in the private pretest versus during the public chat room provided a performance-based measure of peer influence susceptibility. Results In total, 78% of youth provided more risky responses in the chat room than in pretest. The most robust predictor of this change was gender, with boys significantly more susceptible to peer influence than girls. Significant interactions also were noted, with greater susceptibility among boys with later pubertal development and African American boys. Conclusion Results confirm that not all youth are equally susceptible to peer influence. Consistent with sexual script theory, boys evidence greater susceptibility to social pressure regarding sexual behavior than girls. PMID:26794431

Gifts and Corporate Influence in Doctor of Pharmacy Education

PubMed Central

Piascik, Peggy; Bernard, Daphne; Madhavan, Suresh; Stoner, Steve C.; TenHoeve, Tom

2007-01-01

Objectives To explore the nature of corporate gifts directed at PharmD programs and pharmacy student activities and the perceptions of administrators about the potential influences of such gifts. Methods A verbally administered survey of administrative officials at 11 US colleges and schools of pharmacy was conducted and responses were analyzed. Results All respondents indicated accepting corporate gifts or sponsorships for student-related activities in the form of money, grants, scholarships, meals, trinkets, and support for special events, and cited many advantages to corporate partner relationships. Approximately half of the respondents believed that real or potential problems could occur from accepting corporate gifts. Forty-four percent of respondents agreed or strongly agreed that corporate contributions could influence college or school administration. Sixty-one percent agreed or strongly agreed that donations were likely to influence students. Conclusions Corporate gifts do influence college and school of administration and students. Policies should be in place to manage this influence appropriately. PMID:17786255

Development of the Leadership Influence Self-Assessment (LISA©) instrument.

PubMed

Shillam, Casey R; Adams, Jeffrey M; Bryant, Debbie Chatman; Deupree, Joy P; Miyamoto, Suzanne; Gregas, Matt

This study aims to describe the development and psychometric evaluation of the Leadership Influence Self-Assessment (LISA©) tool. LISA© was designed to help nurse leaders assess and enhance their influence capacity by measuring influence traits and practices and identifying areas of strength and weakness. Concepts identified in the Adams Influence Model and input from content experts guided the development of 145 items for testing. Administered to 165 nurse leaders, the assessment was subjected to exploratory factor analysis (EFA). EFA yielded a four-factor solution that comprised 80 items. Cronbach's alpha for factors ranged between 0.912 and 0.938. All factor loadings were >0.4; the smallest factor contained 14 items. Items grouped together in the theoretical model also clustered together in the EFA. Preliminary psychometric testing supports validity and reliability of the LISA© and its potential use as a tool to assess influence capacity for purposes of leadership development and research. Copyright © 2017 Elsevier Inc. All rights reserved.

Managing Competing Influences: Risk Acceptance in Operation Rolling Thunder

DTIC Science & Technology

2017-03-12

Managing Competing Influences: Risk Acceptance in Operation Rolling Thunder A Monograph by Major Benjamin C. Williams US Air Force School of...REPORT TYPE Master’s Thesis 3. DATES COVERED (From - To) JUN 2016 – MAY 2017 4. TITLE AND SUBTITLE Managing Competing Influences: Risk Acceptance in...ANSI Std. Z39.18 ii Monograph Approval Page Name of Candidate: Major Benjamin C. Williams, USAF Monograph Title: Managing Competing Influences

Factors influencing the intention to watch online video advertising.

PubMed

Lee, Joonghwa; Lee, Mira

2011-10-01

This study examines the factors influencing consumer intention to watch online video ads, by applying the theory of reasoned action. The attitude toward watching online video ads, the subjective norm, and prior frequency of watching online video ads positively influence the intention to watch online video ads. Further, beliefs held about entertainment and information outcomes from watching online video ads and subjective norm influence attitude toward watching these ads.

Relational Influences on Career Paths: Siblings in Context

ERIC Educational Resources Information Center

Schultheiss, Donna E. Palladino; Palma, Thomas V.; Predragovich, Krista S.; Glasscock, Julie M. Jeffrey

2002-01-01

This investigation examined participants' perceptions of sibling relational influence on career exploration and decision making. Career path influence on sibling relationships and times when these relationships were most important also were explored. Individual interviews were conducted with urban commuter college students, and narrative data were…

Swedish nurses' perceptions of influencers on patient advocacy: a phenomenographic study.

PubMed

Josse-Eklund, Anna; Jossebo, Marie; Sandin-Bojö, Ann-Kristin; Wilde-Larsson, Bodil; Petzäll, Kerstin

2014-09-01

A limited number of studies have shown that patient advocacy can be influenced by both facilitators and barriers which can encourage and discourage nurses to act as patient advocates. This study's aim was to describe Swedish nurses' perceptions of influencers on patient advocacy. Interviews with 18 registered nurses from different Swedish clinical contexts were analysed using the phenomenographic method. Ethical revisions were made in accordance with national legislation and guidelines by committees for research ethics at Karlstad University. Three levels of hierarchically related influencers on patient advocacy were found in the descriptive categories. The fundamental influencer, the nurse's character traits, was described in the perceptions that advocacy is influenced by nurse's having a moral compass, having control over the care situation, being protective and feeling secure as a nurse. The second most vital influencer, the nurse's bond with the patient, was expressed in the perceptions of knowing the patient and feeling empathy for the patient. The third level of influencers, the organisational conditions, was described in the perceptions that the organisational structures and organisational culture influence patient advocacy. The results correspond with findings from earlier research but add an understanding that influencers on patient advocacy exist at three hierarchically related levels. The nurse's character traits are the fundamental influencer to patient advocacy, but in order to be comfortable and secure when advocating for patients, nurses also need to be familiar with both the patient and the situation. A supposition could be that all influencers interact, which needs to be further addressed in future studies. © The Author(s) 2014.

Sampling Based Influence Maximization on Linear Threshold Model

NASA Astrophysics Data System (ADS)

Jia, Su; Chen, Ling

2018-04-01

A sampling based influence maximization on linear threshold (LT) model method is presented. The method samples the routes in the possible worlds in the social networks, and uses Chernoff bound to estimate the number of samples so that the error can be constrained within a given bound. Then the active possibilities of the routes in the possible worlds are calculated, and are used to compute the influence spread of each node in the network. Our experimental results show that our method can effectively select appropriate seed nodes set that spreads larger influence than other similar methods.

Tobacco Industry Influence on Science and Scientists in Germany

PubMed Central

Grüning, Thilo; Gilmore, Anna B.; McKee, Martin

2006-01-01

Using tobacco industry documents, we examined how and why the tobacco industry sought to influence science and scientists in Germany as a possible factor in explaining the German opposition to stricter tobacco regulation. Smoking and health research programs were organized both separately by individual tobacco companies and jointly through their German trade organization. An extensive network of scientists and scientific institutions with tobacco industry links was developed. Science was distorted in 5 ways: suppression, dilution, distraction, concealment, and manipulation. The extent of tobacco industry influence over the scientific establishment in Germany is profound. The industry introduced serious bias that probably influenced scientific and public opinion in Germany. This influence likely undermined efforts to control tobacco use. PMID:16317203

The influence of psychological factors on tinnitus severity.

PubMed

Milerová, Jana; Anders, Martin; Dvořák, Tomáš; Sand, Philipp G; Königer, Stefanie; Langguth, Berthold

2013-01-01

Subjective tinnitus is a frequent symptom characterized by perception of sound in the absence of a corresponding external stimulus. Although many people learn to live with tinnitus, some find it severely debilitating. Why tinnitus is debilitating in some patients, but not in others, is still incompletely understood. We aimed to assess the influence of different aspects of psychological distress on perceived tinnitus severity. Three hundred seventeen patients diagnosed with chronic subjective tinnitus at two university clinics completed the Tinnitus Handicap Inventory (THI), the Tinnitus Questionnaire (TQ) and the Symptom Check List-90-Revised. The influence of the different dimensions of psychological distress on perceived tinnitus severity was statistically evaluated. Both THI and TQ scores were significantly influenced by gender, site and the dimension "depression". In addition, TQ scores were significantly influenced by age and "somatization," whereas "hostility" had an impact on THI scores only. Psychological aspects as well as sociodemographic variables had a significant influence on both TQ scores. However, our results indicate, that these scales reflect emotional distress of tinnitus sufferers differently. This should be taken into consideration in the use of these scales as screening tools for assessment of tinnitus handicap. Copyright © 2013. Published by Elsevier Inc.

Did the Great Recession influence retirement plans?

PubMed

Szinovacz, Maximiliane E; Davey, Adam; Martin, Lauren

2015-04-01

The recent recession constitutes one of the macro forces that may have influenced workers' retirement plans. We evaluate a multilevel model that addresses the influence of macro-, meso-, and micro-level factors on retirement plans, changes in these plans, and expected retirement age. Using data from Waves 8 and 9 of the Health and Retirement Study (N=2,618), we find that individuals with defined benefit plans are more prone to change toward plans to stop work before the stock market declined, whereas the opposite trend holds for those without pensions. Debts, ability to reduce work hours, and firm unionization also influenced retirement plans. Findings suggest retirement planning education may be particularly important for workers without defined pensions, especially in times of economic volatility. © The Author(s) 2014.

Factors influencing plant invasiveness

Treesearch

Yvette Ortega; Dean Pearson

2009-01-01

Invasiveness of spotted knapweed and biological control agents. Dean and Yvette are examining the influence of drought on the invasiveness of spotted knapweed (Centaurea maculosa) and its susceptibility to herbivory by biological control agents. In collaboration with the University of Montana and Forest Health Protection, researchers have constructed 150...

Sex Differences in Influenceability

ERIC Educational Resources Information Center

Eagly, Alice H.

1978-01-01

Examines the hypothesis that women are more easily influenced than men by reviewing the literature on persuasion and conformity research. Persuasion research and conformity studies not involving group pressure show scant empirical support for sex differences. For group pressure conformity research, a substantial minority of studies support the…

Tantrik influence on sarngadhara.

PubMed

Sharma, P V

1984-01-01

Tantra and Ayurveda are interrelated, particularly during medieval period, Tantra had great impact on the theory and practice of Ayurveda. Hitherto this aspect of history is not sufficiently explored. In this paper, influence of Tantra on Sarngadhara, a representative author of the medieval period, has been vividly brought out.

Peer Influence on Ethnic-Racial Identity Development: A Multi-Site Investigation.

PubMed

Santos, Carlos E; Kornienko, Olga; Rivas-Drake, Deborah

2017-05-01

The peer context features prominently in theory, and increasingly in empirical research, about ethnic-racial identity (ERI) development, but no studies have assessed peer influence on ERI using methods designed to properly assess peer influence. We examined peer influence on ERI centrality, private, and public regard using longitudinal social network analysis. Data were drawn from two sites: a predominantly Latina/o Southwestern (SW) school (N = 1034; Mage = 12.10) and a diverse Midwestern (MW) school (N = 513; Mage = 11.99). Findings showed that peers influenced each other's public regard over time at both sites. However, peer influence on centrality was evident in the SW site, whereas peer influence on private regard was evident in the MW site. Importantly, peer influence was evident after controlling for selection effects. Our integration of developmental, contextual, and social network perspectives offers a fruitful approach to explicate how ERI content may shift in early adolescence as a function of peer influence. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

Direct and Indirect Influence of Altruistic Behavior in a Social Network.

PubMed

Liu, Pei-Pei; Safin, Vasiliy; Yang, Barry; Luhmann, Christian C

2015-01-01

Prior research has suggested that recipients of generosity behave more generously themselves (a direct social influence). In contrast, there is conflicting evidence about the existence of indirect influence (i.e., whether interacting with a recipient of generosity causes one to behave more generously), casting doubt on the possibility that altruistic behavior can cascade through social networks. The current study investigated how far selfish and generous behavior can be transmitted through social networks and the cognitive mechanisms that underlie such transmission. Participants played a sequence of public goods games comprising a chain network. This network is advantageous because it permits only a single, unambiguous path of influence. Furthermore, we experimentally manipulated the behavior of the first link in the chain to be either generous or selfish. Results revealed the presence of direct social influence, but no evidence for indirect influence. Results also showed that selfish behavior exerted a substantially greater influence than generous behavior. Finally, expectations about future partners' behavior strongly mediated the observed social influence, suggesting an adaptive basis for such influence.

Influencers of Career Choice among Allied Health Students.

ERIC Educational Resources Information Center

Brown-West, Anne P.

1991-01-01

Major influences on career choice among 153 allied health students were need to help others, prestige, autonomy, and advancement and income potential. Risk of malpractice suits and Acquired Immune Deficiency Syndrome were negative influences for medical laboratory majors, but not for dietetics and physical therapy majors. (SK)

Evaluating the Influence of Nutrition Determinants on Construction Workers' Food Choices.

PubMed

Okoro, Chioma Sylvia; Musonda, Innocent; Agumba, Justus

2017-11-01

Nutritional knowledge as well as economic, social, biological, and cultural factors have been known to determine an individual's food choices. Despite the existence of research on the factors which influence nutrition globally, there is little known about the extent to which these factors influence the food choices of construction workers, which in turn influence their health and safety during construction activities. The present article investigates the extent to which construction workers' nutrition is influenced by nutritional knowledge, as well as economic, environmental, social, psychological, and physiological factors. A field questionnaire survey was conducted on site construction workers in the Gauteng Province of South Africa. Principal components analysis and multiple regression analysis were used to analyze the data. Findings revealed that consumption of foods termed alternative foods including dairy products, eggs, nuts, fish, and cereals, was influenced by nutritional knowledge and resources. Foods termed traditional core foods were influenced by cultural background; foods termed secondary core foods comprising fruits and vegetables were influenced by economic factors, resources, and cultural background; while foods termed core foods were mostly influenced by nutritional knowledge. By providing evidence of the factors which most influence selection and consumption of certain foods by construction workers, relevant nutrition interventions will be designed and implemented, taking cognizance of these factors.

Evaluating the Influence of Nutrition Determinants on Construction Workers’ Food Choices

PubMed Central

Okoro, Chioma Sylvia; Musonda, Innocent; Agumba, Justus

2016-01-01

Nutritional knowledge as well as economic, social, biological, and cultural factors have been known to determine an individual’s food choices. Despite the existence of research on the factors which influence nutrition globally, there is little known about the extent to which these factors influence the food choices of construction workers, which in turn influence their health and safety during construction activities. The present article investigates the extent to which construction workers’ nutrition is influenced by nutritional knowledge, as well as economic, environmental, social, psychological, and physiological factors. A field questionnaire survey was conducted on site construction workers in the Gauteng Province of South Africa. Principal components analysis and multiple regression analysis were used to analyze the data. Findings revealed that consumption of foods termed alternative foods including dairy products, eggs, nuts, fish, and cereals, was influenced by nutritional knowledge and resources. Foods termed traditional core foods were influenced by cultural background; foods termed secondary core foods comprising fruits and vegetables were influenced by economic factors, resources, and cultural background; while foods termed core foods were mostly influenced by nutritional knowledge. By providing evidence of the factors which most influence selection and consumption of certain foods by construction workers, relevant nutrition interventions will be designed and implemented, taking cognizance of these factors. PMID:26821794

Influence maximization in complex networks through optimal percolation

NASA Astrophysics Data System (ADS)

Morone, Flaviano; Makse, Hernan; CUNY Collaboration; CUNY Collaboration

The whole frame of interconnections in complex networks hinges on a specific set of structural nodes, much smaller than the total size, which, if activated, would cause the spread of information to the whole network, or, if immunized, would prevent the diffusion of a large scale epidemic. Localizing this optimal, that is, minimal, set of structural nodes, called influencers, is one of the most important problems in network science. Here we map the problem onto optimal percolation in random networks to identify the minimal set of influencers, which arises by minimizing the energy of a many-body system, where the form of the interactions is fixed by the non-backtracking matrix of the network. Big data analyses reveal that the set of optimal influencers is much smaller than the one predicted by previous heuristic centralities. Remarkably, a large number of previously neglected weakly connected nodes emerges among the optimal influencers. Reference: F. Morone, H. A. Makse, Nature 524,65-68 (2015)

Factors influencing the implementation of evidence in Chinese nursing practice.

PubMed

Cheng, Lei; Broome, Marion E; Feng, Sheng; Hu, Yan

2017-12-01

To explore the influencing factors from staff nurses, nurse managers, nursing directors and a physician involved in nursing evidence implementation in Mainland China. Although the need for evidence-based nursing is well recognised, continuous efforts are needed to strive for closing the gap from evidence to action. Previous studies have explored influencing factors from individual and organisational perspectives in Western countries. However, it remains unclear what the influences (i.e., context and culture) in the developing countries as China. A grounded theory design using in-depth individual interviews was conducted. Interviews with 56 participants from 24 evidence-based nursing implementation projects were conducted in Mainland China. Constant comparative analysis was used to discover the concepts describing the influencing factors during the implementation process. Factors that influenced implementation of evidence-based practice in the Chinese context were identified. These included the leaders of the projects, the nature of the evidence, practising nurses, patients involved in the projects, the system where the projects were implemented, as well as the influence from outside of the system. A variety of factors influencing evidence implementation in Chinese nursing context were identified and further explored from the perspective of different project leaders and culture influence. There is apparently a strong demand for a supportive system, targeted strategies to facilitate various evidence implementations and integrated core elements of evidence-based practice at the point care. The blurred boundaries and complexity of influencing factors call for a systematic and dynamic perspective during implementation. The competitive priorities emphasise the importance of integration between clinical nursing care and evidence-based practice. © 2017 John Wiley & Sons Ltd.

Perceptions of intimacy and friendship reciprocity moderate peer influence on aggression.

PubMed

Meter, Diana J; Casper, Deborah M; Card, Noel A

2015-01-01

Previous research has shown that close friends' influence can exacerbate adolescents' aggressive behavior, but results of studies which examine whether friendships of greater or lesser qualities moderate peer influence effects are inconsistent. The present study tested whether the perception of the positive friendship quality of intimate exchange and friendship reciprocity moderated best friend influence on participant aggression over time. The 243 participants were approximately 12 years old and ethnically diverse. Neither intimate exchange nor reciprocity significantly moderated friend influence on aggression in a simple way, but the interaction of intimate exchange and friendship reciprocity predicted peer influence on participants' aggression over time. Specifically, highly intimate, nonreciprocal best friendships and less intimate, reciprocal best friendships showed greatest influence when friends' proportion of peer nominations for aggression was high. Reciprocity and intimacy should be considered when predicting peer influence on aggression. © 2014 Wiley Periodicals, Inc.

Factors Influencing Effective Writing.

ERIC Educational Resources Information Center

Muccino, Mary Ann; And Others

Focusing on procedures and strategies suitable for teaching writing to students in grades 4, 6, and 8, this paper examines the factors that have been shown through research to influence effective writing. The paper divides the research examined into the categories of metacognition; socially-based writing strategies; theory-tested approaches to…

The Drive to Influence

ERIC Educational Resources Information Center

Rodriguez, Diego

2017-01-01

At the heart of the educational vocation is a drive to influence, to meaningfully affect the learning and development of others. For adult educators working in higher education, daily activities--from teaching classes to supervising student research to attending faculty meetings to sitting on advisory boards--are full of opportunities to…

The Influence of Peer Groups on Academic Success

ERIC Educational Resources Information Center

Sallee, Margaret W.; Tierney, William G.

2007-01-01

The authors examine how peer relationships influence students' academic success. After defining peer groups, the article considers the ways in which students' peer networks facilitate or inhibit access to academic resources. The authors argue that the composition and purpose of a peer group influences academic achievement and students' likelihood…

Studying Environmental Influence on Motor Development in Children

ERIC Educational Resources Information Center

Gabbard, Carl; Krebs, Ruy

2012-01-01

There is a good argument that in order to truly understand the influences that shape child motor development, one must consider environmental influences that reflect the multilevel ecological contexts that interact with the changing biological characteristics of the child. Although there are theories typically associated with motor development…

32 CFR 147.4 - Guideline B-Foreign influence.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 1 2010-07-01 2010-07-01 false Guideline B-Foreign influence. 147.4 Section 147... CIVILIAN ADJUDICATIVE GUIDELINES FOR DETERMINING ELIGIBILITY FOR ACCESS TO CLASSIFIED INFORMATION Adjudication § 147.4 Guideline B—Foreign influence. (a) The concern. A security risk may exist when an...

A Study of Motivational Influences on Academic Achievement

ERIC Educational Resources Information Center

Dishon-Berkovits, Miriam

2014-01-01

This study examined the influence of motivation on academic achievement. The theoretical rationale for the study is grounded in bridging two influential yet isolated literatures of motivation: goal setting theory and achievement goal theory. Although it is clear that academic performance should be influenced by assigned learning goals,…

Genetic influences on alcohol-related hangover.

PubMed

Slutske, Wendy S; Piasecki, Thomas M; Nathanson, Lisa; Statham, Dixie J; Martin, Nicholas G

2014-12-01

To quantify the relative contributions of genetic and environmental factors to alcohol hangover. Biometric models were used to partition the variance in hangover phenotypes. A community-based sample of Australian twins. Members of the Australian Twin Registry, Cohort II who reported consuming alcohol in the past year when surveyed in 2004-07 (n = 4496). Telephone interviews assessed participants' frequency of drinking to intoxication and frequency of hangover the day after drinking. Analyses examined three phenotypes: hangover frequency, hangover susceptibility (i.e. residual variance in hangover frequency after accounting for intoxication frequency) and hangover resistance (a dichotomous variable defined as having been intoxicated at least once in the past year with no reported hangovers). Genetic factors accounted for 45% [95% confidence interval (CI) = 37-53%] and 40% (95% CI = 33-48%) of the variation in hangover frequency in men and women, respectively. Most of the genetic variation in hangover frequency overlapped with genetic contributions to intoxication frequency. Genetic influences accounted for 24% (95% CI = 14-35%) and 16% (95% CI = 8-25%) of the residual hangover susceptibility variance in men and women, respectively. Forty-three per cent (95% CI = 22-63%) of the variation in hangover resistance was explained by genetic influences, with no evidence for significant sex differences. There was no evidence for shared environmental influences for any of the hangover phenotypes. Individual differences in the propensity to experience a hangover and of being resistant to hangover at a given level of alcohol use are genetically influenced. © 2014 Society for the Study of Addiction.

Environmental influences on human growth and development: historical review and case study of contemporary influences.

PubMed

Schell, Lawrence M; Gallo, Mia V; Ravenscroft, Julia

2009-01-01

Over the past 100 years, the study of environmental influences on human physical growth and development has focused on the influences of social and economic factors; family and household characteristics; urbanization/modernization; nutrition; and features of the physical environment such as altitude, temperature and climate. Continuing in this tradition are current investigations into the roles of pollutants and other aspects of the human-made environment in affecting patterns of human growth and development, specifically the timing of sexual maturation and the development of obesity. Some of the methodological problems in conducting such studies are presented, as are results from an ongoing investigation among one Native American community that show relationships of pollutants to sexual maturation, overweight/obesity and thyroid system function which can impact growth and maturation.

Adolescent Susceptibility to Peer Influence in Sexual Situations.

PubMed

Widman, Laura; Choukas-Bradley, Sophia; Helms, Sarah W; Prinstein, Mitchell J

2016-03-01

One consistent predictor of adolescents' engagement in sexual risk behavior is their belief that peers are engaging in similar behavior; however, not all youth are equally susceptible to these peer influence effects. Understanding individual differences in susceptibility to peer influence is critical to identifying adolescents at risk for negative health outcomes. The purpose of this project was to identify predictors of susceptibility to peer influence using a novel performance-based measure of sexual risk taking. Participants were 300 early adolescents (Mage = 12.6 years; 53% female; 44% Caucasian) who completed (1) a pretest assessment of demographics, sexual attitudes, and hypothetical scenarios measuring the likelihood of engaging in sexual risk behavior and (2) a subsequent experimental procedure that simulated an Internet chat room in which youth believed that they were communicating with peers regarding these same hypothetical scenarios. In reality, these "peers" were computer-programmed e-confederates. Changes in responses to the sexual scenarios in the private pretest versus during the public chat room provided a performance-based measure of peer influence susceptibility. In total, 78% of youth provided more risky responses in the chat room than those in pretest. The most robust predictor of this change was gender, with boys significantly more susceptible to peer influence than girls. Significant interactions also were noted, with greater susceptibility among boys with later pubertal development and African-American boys. Results confirm that not all youth are equally susceptible to peer influence. Consistent with sexual script theory, boys evidence greater susceptibility to social pressure regarding sexual behavior than girls. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Alcohol peer influence of participating in organized school activities: a network approach.

PubMed

Fujimoto, Kayo; Valente, Thomas W

2013-10-01

This study compares the network influences on adolescent substance use from peers who coparticipated in school-sponsored organized activities (affiliation-based peer influence) with the influence both from their "nominated" friends (i.e., the adolescent named the alter as a friend), and only "reciprocated" friends (i.e., both adolescents mutually named each other as friends). The study also attempts to parse affiliation-based peer influence into the influence of both activity members who are also friends and those who are not, to address the potential confounding of these sources of peer influence. The study data consisted of a nationally representative sample of 12,551 adolescents in Grades 7-12 within 106 schools from the Add Health data. Ordinal logistic regression was conducted to estimate the effects of affiliation-based and friends influence on alcohol use and drinking frequency. Peer influence via organized activities (sports or clubs) with drinkers and the influence of friends who drink had significant effects on adolescent drinking. Peer influence through club activities with drinkers had a stronger effect on any drinking behavior than through sports activities with drinkers. After decomposing peer influence through activities by friendship status, influence through sport activities had a significant effect on drinking only when coparticipant drinkers were also reciprocated friends (but not nominated friends), whereas influence through club activities had a significant effect on drinking, regardless of friendship reciprocation. The design and implementation of school based substance use prevention and treatment programs should consider the contextual effects of school-sponsored activities. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Alcohol Peer Influence of Participating in Organized School Activities: A Network Approach

PubMed Central

Valente, Thomas W.

2014-01-01

Objective This study compares the network influences on adolescent substance use from peers who co-participated in school-sponsored organized activities (affiliation-based peer influence) with the influence both from their “nominated” friends (i.e., the adolescent named the alter as a friend), and only “reciprocated” friends (i.e., both adolescents mutually named each other as friends). The study also attempts to parse affiliation-based peer influence into the influence of both activity members who are also friends, and those who are not, to address the potential confounding of these sources of peer influence. Methods The study data consisted of a nationally representative sample of 12,551 adolescents in Grades 7–12 within 106 schools from the Add Health data. Ordinal logistic regression was conducted to estimate the effects of affiliation-based and friends influence on alcohol use and drinking frequency. Results Peer influence via organized activities (sports or clubs) with drinkers and the influence of friends who drink had significant effects on adolescent drinking. Peer influence through club activities with drinkers had a stronger effect on any drinking behavior than through sports activities with drinkers. After decomposing peer influence through activities by friendship status, influence through sport activities had a significant effect on drinking only when co-participant drinkers were also “reciprocated” friends (but not “nominated” friends), whereas influence through club activities had a significant effect on drinking, regardless of friendship reciprocation. Conclusions The design and implementation of school based substance use prevention and treatment programs should consider the contextual effects of school-sponsored activities. PMID:22924449

The influence of positive affect on the components of expectancy motivation.

PubMed

Erez, Amir; Isen, Alice M

2002-12-01

The influence of positive affect on expectancy motivation was investigated in 2 studies. The results of Study 1 indicated that positive affect improved people's performance and affected their perceptions of expectancy and valence. In Study 1, in which outcomes depended on chance, positive affect did not influence people's perceptions of instrumentality. In Study 2, in which the link between performance and outcomes was specified, positive affect influenced all 3 components of expectancy motivation. Together, the results of Studies 1 and 2 indicated that positive affect interacts with task conditions in influencing motivation and that its influence on motivation occurs not through general effects, such as response bias or general activation, but rather through its influence on the cognitive processes involved in motivation.

Tracing the Pathways of Evaluation Influence: From Theory to Practice

ERIC Educational Resources Information Center

Banuelos, Noelle Vargas

2012-01-01

This study sought to explore the ways that evaluation influenced changes in attitudes and actions at the individual and interpersonal levels and the pathways through which this influence occurred, all in a real-world evaluation context. Specifically, Mark & Henry's (2004) proposed model of evaluation influence was used as the framework…

Friends: The Role of Peer Influence across Adolescent Risk Behaviors.

ERIC Educational Resources Information Center

Maxwell, Kimberly A.

2002-01-01

Examined peer influence for 1,969 adolescents across 5 risk behaviors: smoking, alcohol consumption, marijuana use, tobacco chewing, and sexual debut. Results show that a random same-sex peer predicts a teen's risk behavior initiation through influence to initiate cigarette and marijuana use, and influence to initiate and stop alcohol and chewing…

Influencing organisational culture: a leadership challenge.

PubMed

Muls, Ann; Dougherty, Lisa; Doyle, Natalie; Shaw, Clare; Soanes, Louise; Stevens, Anna-Marie

In the wake of the Francis report, the need for NHS trusts and hospitals to adopt a culture of learning, safety and transparency has been highlighted. This article considers different aspects of culture in health care, and hones in on the link between culture and safety for patients in putting the patient first, embedding the 6Cs and considering the options to measure and influence organisational culture. The article reflects more deeply on how leadership across all levels can influence and inspire change in organisational culture, ensuring that the patient remains the focus of any changes in care delivery.

[Influence of stress on learning and memory].

PubMed

Ukai, M

2000-08-01

This paper describes the influence of stress on learning and memory. The mice receiving inescapable electroshock fail to perform the active conditioned avoidance response of lever-pressing. This is called learned helplessness, which is ameliorated by treatment with antidepressants including one of the selective serotonin reuptake inhibitors (SSRIs). It is of particular interest that posttraumatic stress disease (PTSD) accompanied by memory impairment could be improved by treatment with SSRIs. The different kinds of stress including ischemia, footshock, psychological stress, and forced swimming influence learning and memory as indexed by spontaneous alternation performance as well as passive avoidance learning. In addition, a variety of stresses influence the activity of hormones and neurotransmitters like monoamines, neuropeptides, and excitatory amino acids resulting in changes in learning and memory. Finally, the accumulation of data is necessary to clarify the exact mechanism of stress on learning and memory.

Influencers of career choice among allied health students.

PubMed

Brown-West, A P

1991-01-01

This study focused on the factors that influence students' choice of an allied health profession. A survey of 153 students in three allied health programs at the University of Connecticut revealed that "the need to help others," "prestige," "professional autonomy," "opportunities for advancement," "income potential," and "the effect of the specialty on family and personal life," were the major influencers of career choice among allied health students. Only a few students regarded malpractice suits and AIDS as negative influencers. While medical laboratory science majors regarded these as important factors, dietetics and physical therapy majors did not. The article suggests further use of these findings by program directors and career counselors.

Socioeconomic status and genetic influences on cognitive development.

PubMed

Figlio, David N; Freese, Jeremy; Karbownik, Krzysztof; Roth, Jeffrey

2017-12-19

Accurate understanding of environmental moderation of genetic influences is vital to advancing the science of cognitive development as well as for designing interventions. One widely reported idea is increasing genetic influence on cognition for children raised in higher socioeconomic status (SES) families, including recent proposals that the pattern is a particularly US phenomenon. We used matched birth and school records from Florida siblings and twins born in 1994-2002 to provide the largest, most population-diverse consideration of this hypothesis to date. We found no evidence of SES moderation of genetic influence on test scores, suggesting that articulating gene-environment interactions for cognition is more complex and elusive than previously supposed.

Influencing organizations to promote health: applying stakeholder theory.

PubMed

Kok, Gerjo; Gurabardhi, Zamira; Gottlieb, Nell H; Zijlstra, Fred R H

2015-04-01

Stakeholder theory may help health promoters to make changes at the organizational and policy level to promote health. A stakeholder is any individual, group, or organization that can influence an organization. The organization that is the focus for influence attempts is called the focal organization. The more salient a stakeholder is and the more central in the network, the stronger the influence. As stakeholders, health promoters may use communicative, compromise, deinstitutionalization, or coercive methods through an ally or a coalition. A hypothetical case study, involving adolescent use of harmful legal products, illustrates the process of applying stakeholder theory to strategic decision making. © 2015 Society for Public Health Education.

Influence of liquid lubricant properties on their performance

NASA Technical Reports Server (NTRS)

Wedeven, V.

1972-01-01

The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation. Since the lubrication of practical surfaces usually involves boundary as well as hydrodynamic mechanisms, both the chemical and physical properties significantly influence the lubricant's performance.

Perceptions of intimacy and friendship reciprocity moderate peer influence on aggression.

PubMed

Meter, Diana J; Casper, Deborah M; Card, Noel A

2014-12-15

Previous research has shown that close friends' influence can exacerbate adolescents' aggressive behavior, but results of studies which examine whether friendships of greater or lesser qualities moderate peer influence effects are inconsistent. The present study tested whether the perception of the positive friendship quality of intimate exchange and friendship reciprocity moderated best friend influence on participant aggression over time. The 243 participants were approximately 12 years old and ethnically diverse. Neither intimate exchange nor reciprocity significantly moderated friend influence on aggression in a simple way, but the interaction of intimate exchange and friendship reciprocity predicted peer influence on participants' aggression over time. Specifically, highly intimate, nonreciprocal best friendships and less intimate, reciprocal best friendships showed greatest influence when friends' proportion of peer nominations for aggression was high. Reciprocity and intimacy should be considered when predicting peer influence on aggression. Aggr. Behav. 9999:1-11, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

Neural computations underpinning the strategic management of influence in advice giving.

PubMed

Hertz, Uri; Palminteri, Stefano; Brunetti, Silvia; Olesen, Cecilie; Frith, Chris D; Bahrami, Bahador

2017-12-19

Research on social influence has focused mainly on the target of influence (e.g., consumer and voter); thus, the cognitive and neurobiological underpinnings of the source of the influence (e.g., politicians and salesmen) remain unknown. Here, in a three-sided advice-giving game, two advisers competed to influence a client by modulating their own confidence in their advice about which lottery the client should choose. We report that advisers' strategy depends on their level of influence on the client and their merit relative to one another. Moreover, blood-oxygenation-level-dependent (BOLD) signal in the temporo-parietal junction is modulated by adviser's current level of influence on the client, and relative merit prediction error affects activity in medial-prefrontal cortex. Both types of social information modulate ventral striatum response. By demonstrating what happens in our mind and brain when we try to influence others, these results begin to explain the biological mechanisms that shape inter-individual differences in social conduct.

Influence maximization in social networks under an independent cascade-based model

NASA Astrophysics Data System (ADS)

Wang, Qiyao; Jin, Yuehui; Lin, Zhen; Cheng, Shiduan; Yang, Tan

2016-02-01

The rapid growth of online social networks is important for viral marketing. Influence maximization refers to the process of finding influential users who make the most of information or product adoption. An independent cascade-based model for influence maximization, called IMIC-OC, was proposed to calculate positive influence. We assumed that influential users spread positive opinions. At the beginning, users held positive or negative opinions as their initial opinions. When more users became involved in the discussions, users balanced their own opinions and those of their neighbors. The number of users who did not change positive opinions was used to determine positive influence. Corresponding influential users who had maximum positive influence were then obtained. Experiments were conducted on three real networks, namely, Facebook, HEP-PH and Epinions, to calculate maximum positive influence based on the IMIC-OC model and two other baseline methods. The proposed model resulted in larger positive influence, thus indicating better performance compared with the baseline methods.

Influence of convection on microstructure

NASA Technical Reports Server (NTRS)

Wilcox, William R.; Regel, Liya L.

1994-01-01

The primary motivation for this research was to determine the cause for space processing altering the microstructure of some eutectics, especially the MnBi-Bi eutectic. Four primary hypotheses were to be tested under this current grant: (1) A fibrous microstructure is much more sensitive to convection than a lamellar microstructure, which was assumed in our prior theoretical treatment. (2) An interface with one phase projecting out into the melt is much more sensitive to convection than a planar interface, which was assumed in our prior theoretical treatment. (3) The Soret effect is much more important in the absence of convection and has a sufficiently large influence on microstructure that its action can explain the flight results. (4) The microstructure is much more sensitive to convection when the composition of the bulk melt is off eutectic. These hypotheses were tested. It was concluded that none of these can explain the Grumman flight results. Experiments also were performed on the influence of current pulses on MnBi-Bi microstructure. A thorough review was made of all experimental results on the influence of convection on the fiber spacing in rod eutectics, including results from solidification in space or at high gravity, and use of mechanical stirring or a magnetic field. Contradictory results were noted. The predictions of models for convective influences were compared with the experimental results. Vigorous mechanical stirring appears to coarsen the microstructure by altering the concentration field in front of the freezing interface. Gentle convection is believed to alter the microstructure of a fibrous eutectic only when it causes a fluctuating freezing rate with a system for which the kinetics of fiber branching differs from that for fiber termination. These fluctuations may cause the microstructure to coarsen or to become finer, depending on the relative kinetics of these processes. The microstructure of lamellar eutectics is less sensitive to

Can Subliminal Influence Be Applied To Education/Training?

ERIC Educational Resources Information Center

Ogunyemi, Olatunde

1993-01-01

Explores the use of subliminal influence, where embedded stimuli, too small or too vague to be consciously recognized, are placed within text to influence student learning. Examines the technique's ability to improve learning/performance. Addresses such issues as the legality of using the technique, responsibilities of the trainer/instructor, and…

Community Influence on Adolescent Obesity: Race/Ethnic Differences

ERIC Educational Resources Information Center

Wickrama, K. A. Thulitha; Wickrama, K. A. S.; Bryant, Chalandra M.

2006-01-01

Using a sample of 20,000 adolescents (Add Health data), this study examined the influences of community poverty and race/ethnicity on adolescent obesity. Multilevel analyses revealed strong evidence for the unique influences of community poverty and race/ethnicity on adolescent obesity net of family characteristics. The prevalence of obesity is…

Local Influence Analysis of Nonlinear Structural Equation Models

ERIC Educational Resources Information Center

Lee, Sik-Yum; Tang, Nian-Sheng

2004-01-01

By regarding the latent random vectors as hypothetical missing data and based on the conditional expectation of the complete-data log-likelihood function in the EM algorithm, we investigate assessment of local influence of various perturbation schemes in a nonlinear structural equation model. The basic building blocks of local influence analysis…

Evidence-Based Kernels: Fundamental Units of Behavioral Influence

ERIC Educational Resources Information Center

Embry, Dennis D.; Biglan, Anthony

2008-01-01

This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior-influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of…

Parental influences on adolescent decision making and contraceptive use.

PubMed

Commendador, Kathleen A

2010-01-01

This article reviews the literature in the area of parental and maternal influences on contraceptive decision making, thus determining future directions of research and potential interventions. A review of published literature using PubMed, CINAHL, Infotrak, Science and Technology, and Medline spanning 1980-2007 was used to gather information. Results from 35 research studies and 15 scholarly articles were included. The search terms adolescent decision making, maternal influences on adolescent contraceptive decision making, adolescent contraceptive decision making, paternal influences on adolescent decision making, and contraception were used to gather data. The literature reveals there is an association between parental communication, parenting style, and adolescent sexual activity and contraception use. Maternal communication has been shown to delay sexual intercourse and increase contraceptive use. Maternal communication has rich potential as an intervention to impact positive adolescent sexual decision making and contraception use. Gaps in the research identified were the lack of studies on the influences on parenting style and the father/adolescent influences on sexual initiation and contraceptive decision making.

Influence of Friends on Children’s Physical Activity: A Review

PubMed Central

Maturo, Claire C.

2013-01-01

We examined evidence for friendship influences on children's physical activity (PA) through systematic searches of online databases in May 2012. We identified 106 studies (25 qualitative) published in English since 2000 that analyzed indicators of friendship influences (e.g., communication about PA, friends’ PA, and PA with friends) among persons younger than 19 years. Children's PA was positively associated with encouragement from friends (43 of 55 studies indicating a positive relationship), friends' own PA (30/35), and engagement with friends in PA (9/10). These findings are consistent with friends influencing PA, but most studies did not isolate influence from other factors that could explain similarity. Understanding friendship influences in childhood can facilitate the promotion of lifelong healthy habits. PA with friends should be considered in health promotion programs. PMID:23678914

Status, Numbers and Influence

ERIC Educational Resources Information Center

Melamed, David; Savage, Scott V.

2013-01-01

We develop a theoretical model of social influence in n-person groups. We argue that disagreement between group members introduces uncertainty into the social situation, and this uncertainty motivates people to use status characteristics to evaluate the merits of a particular opinion. Our model takes the numerical distribution of opinions and the…

Peer influence on gender identity development in adolescence.

PubMed

Kornienko, Olga; Santos, Carlos E; Martin, Carol Lynn; Granger, Kristen L

2016-10-01

During adolescence, gender identity (GI) develops through a dialectic process of personal reflection and with input from the social environment. Peers play an important role in the socialization of gendered behavior, but no studies to-date have assessed peer influences on GI. Thus, the goal of the present study was to examine peer influences on four aspects of adolescents' GI in racially and ethnically diverse 7th- and 8th-grade students (N = 670; 49.5% boys, M age = 12.64) using a longitudinal social network modeling approach. We hypothesized stronger peer influence effects on between-gender dimensions of GI (intergroup bias and felt pressure for gender conformity) than on within-gender dimensions of GI (typicality and contentedness). Consistent with expectations, we found significant peer influence on between-gender components of GI-intergroup bias among 7th and 8th graders as well as felt pressure for gender conformity among 8th graders. In contrast, within-gender components of GI showed no evidence of peer influence. Importantly, these peer socialization effects were evident even when controlling for tendencies to select friends who were similar on gender, gender typicality, and contentedness (8th graders only). Employing longitudinal social network analyses provides insights into and clarity about the roles of peers in gender development. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Influence maximization in complex networks through optimal percolation

NASA Astrophysics Data System (ADS)

Morone, Flaviano; Makse, Hernán A.

2015-08-01

The whole frame of interconnections in complex networks hinges on a specific set of structural nodes, much smaller than the total size, which, if activated, would cause the spread of information to the whole network, or, if immunized, would prevent the diffusion of a large scale epidemic. Localizing this optimal, that is, minimal, set of structural nodes, called influencers, is one of the most important problems in network science. Despite the vast use of heuristic strategies to identify influential spreaders, the problem remains unsolved. Here we map the problem onto optimal percolation in random networks to identify the minimal set of influencers, which arises by minimizing the energy of a many-body system, where the form of the interactions is fixed by the non-backtracking matrix of the network. Big data analyses reveal that the set of optimal influencers is much smaller than the one predicted by previous heuristic centralities. Remarkably, a large number of previously neglected weakly connected nodes emerges among the optimal influencers. These are topologically tagged as low-degree nodes surrounded by hierarchical coronas of hubs, and are uncovered only through the optimal collective interplay of all the influencers in the network. The present theoretical framework may hold a larger degree of universality, being applicable to other hard optimization problems exhibiting a continuous transition from a known phase.

Influence maximization in complex networks through optimal percolation.

PubMed

Morone, Flaviano; Makse, Hernán A

2015-08-06

The whole frame of interconnections in complex networks hinges on a specific set of structural nodes, much smaller than the total size, which, if activated, would cause the spread of information to the whole network, or, if immunized, would prevent the diffusion of a large scale epidemic. Localizing this optimal, that is, minimal, set of structural nodes, called influencers, is one of the most important problems in network science. Despite the vast use of heuristic strategies to identify influential spreaders, the problem remains unsolved. Here we map the problem onto optimal percolation in random networks to identify the minimal set of influencers, which arises by minimizing the energy of a many-body system, where the form of the interactions is fixed by the non-backtracking matrix of the network. Big data analyses reveal that the set of optimal influencers is much smaller than the one predicted by previous heuristic centralities. Remarkably, a large number of previously neglected weakly connected nodes emerges among the optimal influencers. These are topologically tagged as low-degree nodes surrounded by hierarchical coronas of hubs, and are uncovered only through the optimal collective interplay of all the influencers in the network. The present theoretical framework may hold a larger degree of universality, being applicable to other hard optimization problems exhibiting a continuous transition from a known phase.

Common genetic variants influence human subcortical brain structures.

PubMed

Hibar, Derrek P; Stein, Jason L; Renteria, Miguel E; Arias-Vasquez, Alejandro; Desrivières, Sylvane; Jahanshad, Neda; Toro, Roberto; Wittfeld, Katharina; Abramovic, Lucija; Andersson, Micael; Aribisala, Benjamin S; Armstrong, Nicola J; Bernard, Manon; Bohlken, Marc M; Boks, Marco P; Bralten, Janita; Brown, Andrew A; Chakravarty, M Mallar; Chen, Qiang; Ching, Christopher R K; Cuellar-Partida, Gabriel; den Braber, Anouk; Giddaluru, Sudheer; Goldman, Aaron L; Grimm, Oliver; Guadalupe, Tulio; Hass, Johanna; Woldehawariat, Girma; Holmes, Avram J; Hoogman, Martine; Janowitz, Deborah; Jia, Tianye; Kim, Sungeun; Klein, Marieke; Kraemer, Bernd; Lee, Phil H; Olde Loohuis, Loes M; Luciano, Michelle; Macare, Christine; Mather, Karen A; Mattheisen, Manuel; Milaneschi, Yuri; Nho, Kwangsik; Papmeyer, Martina; Ramasamy, Adaikalavan; Risacher, Shannon L; Roiz-Santiañez, Roberto; Rose, Emma J; Salami, Alireza; Sämann, Philipp G; Schmaal, Lianne; Schork, Andrew J; Shin, Jean; Strike, Lachlan T; Teumer, Alexander; van Donkelaar, Marjolein M J; van Eijk, Kristel R; Walters, Raymond K; Westlye, Lars T; Whelan, Christopher D; Winkler, Anderson M; Zwiers, Marcel P; Alhusaini, Saud; Athanasiu, Lavinia; Ehrlich, Stefan; Hakobjan, Marina M H; Hartberg, Cecilie B; Haukvik, Unn K; Heister, Angelien J G A M; Hoehn, David; Kasperaviciute, Dalia; Liewald, David C M; Lopez, Lorna M; Makkinje, Remco R R; Matarin, Mar; Naber, Marlies A M; McKay, D Reese; Needham, Margaret; Nugent, Allison C; Pütz, Benno; Royle, Natalie A; Shen, Li; Sprooten, Emma; Trabzuni, Daniah; van der Marel, Saskia S L; van Hulzen, Kimm J E; Walton, Esther; Wolf, Christiane; Almasy, Laura; Ames, David; Arepalli, Sampath; Assareh, Amelia A; Bastin, Mark E; Brodaty, Henry; Bulayeva, Kazima B; Carless, Melanie A; Cichon, Sven; Corvin, Aiden; Curran, Joanne E; Czisch, Michael; de Zubicaray, Greig I; Dillman, Allissa; Duggirala, Ravi; Dyer, Thomas D; Erk, Susanne; Fedko, Iryna O; Ferrucci, Luigi; Foroud, Tatiana M; Fox, Peter T; Fukunaga, Masaki; Gibbs, J Raphael; Göring, Harald H H; Green, Robert C; Guelfi, Sebastian; Hansell, Narelle K; Hartman, Catharina A; Hegenscheid, Katrin; Heinz, Andreas; Hernandez, Dena G; Heslenfeld, Dirk J; Hoekstra, Pieter J; Holsboer, Florian; Homuth, Georg; Hottenga, Jouke-Jan; Ikeda, Masashi; Jack, Clifford R; Jenkinson, Mark; Johnson, Robert; Kanai, Ryota; Keil, Maria; Kent, Jack W; Kochunov, Peter; Kwok, John B; Lawrie, Stephen M; Liu, Xinmin; Longo, Dan L; McMahon, Katie L; Meisenzahl, Eva; Melle, Ingrid; Mohnke, Sebastian; Montgomery, Grant W; Mostert, Jeanette C; Mühleisen, Thomas W; Nalls, Michael A; Nichols, Thomas E; Nilsson, Lars G; Nöthen, Markus M; Ohi, Kazutaka; Olvera, Rene L; Perez-Iglesias, Rocio; Pike, G Bruce; Potkin, Steven G; Reinvang, Ivar; Reppermund, Simone; Rietschel, Marcella; Romanczuk-Seiferth, Nina; Rosen, Glenn D; Rujescu, Dan; Schnell, Knut; Schofield, Peter R; Smith, Colin; Steen, Vidar M; Sussmann, Jessika E; Thalamuthu, Anbupalam; Toga, Arthur W; Traynor, Bryan J; Troncoso, Juan; Turner, Jessica A; Valdés Hernández, Maria C; van 't Ent, Dennis; van der Brug, Marcel; van der Wee, Nic J A; van Tol, Marie-Jose; Veltman, Dick J; Wassink, Thomas H; Westman, Eric; Zielke, Ronald H; Zonderman, Alan B; Ashbrook, David G; Hager, Reinmar; Lu, Lu; McMahon, Francis J; Morris, Derek W; Williams, Robert W; Brunner, Han G; Buckner, Randy L; Buitelaar, Jan K; Cahn, Wiepke; Calhoun, Vince D; Cavalleri, Gianpiero L; Crespo-Facorro, Benedicto; Dale, Anders M; Davies, Gareth E; Delanty, Norman; Depondt, Chantal; Djurovic, Srdjan; Drevets, Wayne C; Espeseth, Thomas; Gollub, Randy L; Ho, Beng-Choon; Hoffmann, Wolfgang; Hosten, Norbert; Kahn, René S; Le Hellard, Stephanie; Meyer-Lindenberg, Andreas; Müller-Myhsok, Bertram; Nauck, Matthias; Nyberg, Lars; Pandolfo, Massimo; Penninx, Brenda W J H; Roffman, Joshua L; Sisodiya, Sanjay M; Smoller, Jordan W; van Bokhoven, Hans; van Haren, Neeltje E M; Völzke, Henry; Walter, Henrik; Weiner, Michael W; Wen, Wei; White, Tonya; Agartz, Ingrid; Andreassen, Ole A; Blangero, John; Boomsma, Dorret I; Brouwer, Rachel M; Cannon, Dara M; Cookson, Mark R; de Geus, Eco J C; Deary, Ian J; Donohoe, Gary; Fernández, Guillén; Fisher, Simon E; Francks, Clyde; Glahn, David C; Grabe, Hans J; Gruber, Oliver; Hardy, John; Hashimoto, Ryota; Hulshoff Pol, Hilleke E; Jönsson, Erik G; Kloszewska, Iwona; Lovestone, Simon; Mattay, Venkata S; Mecocci, Patrizia; McDonald, Colm; McIntosh, Andrew M; Ophoff, Roel A; Paus, Tomas; Pausova, Zdenka; Ryten, Mina; Sachdev, Perminder S; Saykin, Andrew J; Simmons, Andy; Singleton, Andrew; Soininen, Hilkka; Wardlaw, Joanna M; Weale, Michael E; Weinberger, Daniel R; Adams, Hieab H H; Launer, Lenore J; Seiler, Stephan; Schmidt, Reinhold; Chauhan, Ganesh; Satizabal, Claudia L; Becker, James T; Yanek, Lisa; van der Lee, Sven J; Ebling, Maritza; Fischl, Bruce; Longstreth, W T; Greve, Douglas; Schmidt, Helena; Nyquist, Paul; Vinke, Louis N; van Duijn, Cornelia M; Xue, Luting; Mazoyer, Bernard; Bis, Joshua C; Gudnason, Vilmundur; Seshadri, Sudha; Ikram, M Arfan; Martin, Nicholas G; Wright, Margaret J; Schumann, Gunter; Franke, Barbara; Thompson, Paul M; Medland, Sarah E

2015-04-09

The highly complex structure of the human brain is strongly shaped by genetic influences. Subcortical brain regions form circuits with cortical areas to coordinate movement, learning, memory and motivation, and altered circuits can lead to abnormal behaviour and disease. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume and intracranial volume. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10(-33); 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability in human brain development, and may help to determine mechanisms of neuropsychiatric dysfunction.

What factors influence British medical students' career intentions?

PubMed

Ibrahim, Michael; Fanshawe, Angela; Patel, Vanash; Goswami, Karan; Chilvers, Geoffrey; Ting, Michelle; Pilavakis, Yiannis; Rao, Christopher; Athanasiou, Thanos

2014-12-01

The aim of this study was to identify factors that influence career choice in UK medical students. Students at seven institutions were invited to rate how important various factors were on influencing their career choices and how interested they were in pursuing different specialties. The influence of interpersonal relationship networks on career choice was also evaluated. 641 responses were collected. 44% (283) were male, 16% (105) were graduates and 41% (263) were final-year students. For Dermatology (p = 0.009), Paediatrics (p = 0.000), Radiology (p = 0.000), Emergency Medicine (p = 0.018) and Cardiothoracic Surgery (p = 0.000), there was a clear correlation between completing a clinical attachment and an interest in pursuing the specialty. Perceived characteristics of the speciality, individually and in clusters were considered important by specific subgroups of students, such as those interested in surgery. These students considered prestige (p = 0.0003), role models (p = 0.014), financial rewards after training (p = 0.0196) and technical challenge (p = 0.0011) as important factors. Demographics such as sex and age played a significant role in career choice. Interpersonal relationship networks do not have a significant influence on career intentions. This study shows that the career intentions of British medical students are influenced by their undergraduate experience and by the weight they place on different specialty-related factors.

Common genetic variants influence human subcortical brain structures

PubMed Central

Hibar, Derrek P.; Stein, Jason L.; Renteria, Miguel E.; Arias-Vasquez, Alejandro; Desrivières, Sylvane; Jahanshad, Neda; Toro, Roberto; Wittfeld, Katharina; Abramovic, Lucija; Andersson, Micael; Aribisala, Benjamin S.; Armstrong, Nicola J.; Bernard, Manon; Bohlken, Marc M.; Boks, Marco P.; Bralten, Janita; Brown, Andrew A.; Chakravarty, M. Mallar; Chen, Qiang; Ching, Christopher R. K.; Cuellar-Partida, Gabriel; den Braber, Anouk; Giddaluru, Sudheer; Goldman, Aaron L.; Grimm, Oliver; Guadalupe, Tulio; Hass, Johanna; Woldehawariat, Girma; Holmes, Avram J.; Hoogman, Martine; Janowitz, Deborah; Jia, Tianye; Kim, Sungeun; Klein, Marieke; Kraemer, Bernd; Lee, Phil H.; Olde Loohuis, Loes M.; Luciano, Michelle; Macare, Christine; Mather, Karen A.; Mattheisen, Manuel; Milaneschi, Yuri; Nho, Kwangsik; Papmeyer, Martina; Ramasamy, Adaikalavan; Risacher, Shannon L.; Roiz-Santiañez, Roberto; Rose, Emma J.; Salami, Alireza; Sämann, Philipp G.; Schmaal, Lianne; Schork, Andrew J.; Shin, Jean; Strike, Lachlan T.; Teumer, Alexander; van Donkelaar, Marjolein M. J.; van Eijk, Kristel R.; Walters, Raymond K.; Westlye, Lars T.; Whelan, Christopher D.; Winkler, Anderson M.; Zwiers, Marcel P.; Alhusaini, Saud; Athanasiu, Lavinia; Ehrlich, Stefan; Hakobjan, Marina M. H.; Hartberg, Cecilie B.; Haukvik, Unn K.; Heister, Angelien J. G. A. M.; Hoehn, David; Kasperaviciute, Dalia; Liewald, David C. M.; Lopez, Lorna M.; Makkinje, Remco R. R.; Matarin, Mar; Naber, Marlies A. M.; McKay, D. Reese; Needham, Margaret; Nugent, Allison C.; Pütz, Benno; Royle, Natalie A.; Shen, Li; Sprooten, Emma; Trabzuni, Daniah; van der Marel, Saskia S. L.; van Hulzen, Kimm J. E.; Walton, Esther; Wolf, Christiane; Almasy, Laura; Ames, David; Arepalli, Sampath; Assareh, Amelia A.; Bastin, Mark E.; Brodaty, Henry; Bulayeva, Kazima B.; Carless, Melanie A.; Cichon, Sven; Corvin, Aiden; Curran, Joanne E.; Czisch, Michael; de Zubicaray, Greig I.; Dillman, Allissa; Duggirala, Ravi; Dyer, Thomas D.; Erk, Susanne; Fedko, Iryna O.; Ferrucci, Luigi; Foroud, Tatiana M.; Fox, Peter T.; Fukunaga, Masaki; Gibbs, J. Raphael; Göring, Harald H. H.; Green, Robert C.; Guelfi, Sebastian; Hansell, Narelle K.; Hartman, Catharina A.; Hegenscheid, Katrin; Heinz, Andreas; Hernandez, Dena G.; Heslenfeld, Dirk J.; Hoekstra, Pieter J.; Holsboer, Florian; Homuth, Georg; Hottenga, Jouke-Jan; Ikeda, Masashi; Jack, Clifford R.; Jenkinson, Mark; Johnson, Robert; Kanai, Ryota; Keil, Maria; Kent, Jack W.; Kochunov, Peter; Kwok, John B.; Lawrie, Stephen M.; Liu, Xinmin; Longo, Dan L.; McMahon, Katie L.; Meisenzahl, Eva; Melle, Ingrid; Mohnke, Sebastian; Montgomery, Grant W.; Mostert, Jeanette C.; Mühleisen, Thomas W.; Nalls, Michael A.; Nichols, Thomas E.; Nilsson, Lars G.; Nöthen, Markus M.; Ohi, Kazutaka; Olvera, Rene L.; Perez-Iglesias, Rocio; Pike, G. Bruce; Potkin, Steven G.; Reinvang, Ivar; Reppermund, Simone; Rietschel, Marcella; Romanczuk-Seiferth, Nina; Rosen, Glenn D.; Rujescu, Dan; Schnell, Knut; Schofield, Peter R.; Smith, Colin; Steen, Vidar M.; Sussmann, Jessika E.; Thalamuthu, Anbupalam; Toga, Arthur W.; Traynor, Bryan J.; Troncoso, Juan; Turner, Jessica A.; Valdés Hernández, Maria C.; van ’t Ent, Dennis; van der Brug, Marcel; van der Wee, Nic J. A.; van Tol, Marie-Jose; Veltman, Dick J.; Wassink, Thomas H.; Westman, Eric; Zielke, Ronald H.; Zonderman, Alan B.; Ashbrook, David G.; Hager, Reinmar; Lu, Lu; McMahon, Francis J.; Morris, Derek W.; Williams, Robert W.; Brunner, Han G.; Buckner, Randy L.; Buitelaar, Jan K.; Cahn, Wiepke; Calhoun, Vince D.; Cavalleri, Gianpiero L.; Crespo-Facorro, Benedicto; Dale, Anders M.; Davies, Gareth E.; Delanty, Norman; Depondt, Chantal; Djurovic, Srdjan; Drevets, Wayne C.; Espeseth, Thomas; Gollub, Randy L.; Ho, Beng-Choon; Hoffmann, Wolfgang; Hosten, Norbert; Kahn, René S.; Le Hellard, Stephanie; Meyer-Lindenberg, Andreas; Müller-Myhsok, Bertram; Nauck, Matthias; Nyberg, Lars; Pandolfo, Massimo; Penninx, Brenda W. J. H.; Roffman, Joshua L.; Sisodiya, Sanjay M.; Smoller, Jordan W.; van Bokhoven, Hans; van Haren, Neeltje E. M.; Völzke, Henry; Walter, Henrik; Weiner, Michael W.; Wen, Wei; White, Tonya; Agartz, Ingrid; Andreassen, Ole A.; Blangero, John; Boomsma, Dorret I.; Brouwer, Rachel M.; Cannon, Dara M.; Cookson, Mark R.; de Geus, Eco J. C.; Deary, Ian J.; Donohoe, Gary; Fernández, Guillén; Fisher, Simon E.; Francks, Clyde; Glahn, David C.; Grabe, Hans J.; Gruber, Oliver; Hardy, John; Hashimoto, Ryota; Hulshoff Pol, Hilleke E.; Jönsson, Erik G.; Kloszewska, Iwona; Lovestone, Simon; Mattay, Venkata S.; Mecocci, Patrizia; McDonald, Colm; McIntosh, Andrew M.; Ophoff, Roel A.; Paus, Tomas; Pausova, Zdenka; Ryten, Mina; Sachdev, Perminder S.; Saykin, Andrew J.; Simmons, Andy; Singleton, Andrew; Soininen, Hilkka; Wardlaw, Joanna M.; Weale, Michael E.; Weinberger, Daniel R.; Adams, Hieab H. H.; Launer, Lenore J.; Seiler, Stephan; Schmidt, Reinhold; Chauhan, Ganesh; Satizabal, Claudia L.; Becker, James T.; Yanek, Lisa; van der Lee, Sven J.; Ebling, Maritza; Fischl, Bruce; Longstreth, W. T.; Greve, Douglas; Schmidt, Helena; Nyquist, Paul; Vinke, Louis N.; van Duijn, Cornelia M.; Xue, Luting; Mazoyer, Bernard; Bis, Joshua C.; Gudnason, Vilmundur; Seshadri, Sudha; Ikram, M. Arfan; Martin, Nicholas G.; Wright, Margaret J.; Schumann, Gunter; Franke, Barbara; Thompson, Paul M.; Medland, Sarah E.

2015-01-01

The highly complex structure of the human brain is strongly shaped by genetic influences1. Subcortical brain regions form circuits with cortical areas to coordinate movement2, learning, memory3 and motivation4, and altered circuits can lead to abnormal behaviour and disease2. To investigate how common genetic variants affect the structure of these brain regions, here we conduct genome-wide association studies of the volumes of seven subcortical regions and the intracranial volume derived from magnetic resonance images of 30,717 individuals from 50 cohorts. We identify five novel genetic variants influencing the volumes of the putamen and caudate nucleus. We also find stronger evidence for three loci with previously established influences on hippocampal volume5 and intracranial volume6. These variants show specific volumetric effects on brain structures rather than global effects across structures. The strongest effects were found for the putamen, where a novel intergenic locus with replicable influence on volume (rs945270; P = 1.08 × 10−33; 0.52% variance explained) showed evidence of altering the expression of the KTN1 gene in both brain and blood tissue. Variants influencing putamen volume clustered near developmental genes that regulate apoptosis, axon guidance and vesicle transport. Identification of these genetic variants provides insight into the causes of variability inhuman brain development, and may help to determine mechanisms of neuropsychiatric dysfunction. PMID:25607358

Co-production and time use. Influence on product evaluation.

PubMed

Heide, Morten; Olsen, Svein Ottar

2011-02-01

This study analyses how time use influences consumers' evaluation of a product and their satisfaction with the co-production activity. It also includes hypotheses about how knowledge and perceived convenience are related to the evaluative constructs. The constructs are checked for reliability and validity, before using structural equation modelling in Lisrel to estimate the relationships between the constructs and their measures. The results showed that time use had a negative influence on perceived convenience and a positive effect on satisfaction with co-production, but did not influence the global evaluation of the product. Satisfaction with co-production and perceived convenience had a positive influence on the global evaluation. Knowledge had a negative influence on time use. Finally, knowledge and perceived convenience had a positive relationship with satisfaction with co-production. In total, seven out of nine hypotheses are supported by the data. The study suggests that time use, perceived convenience, and satisfaction with co-production can be an important variables in the understanding of the evaluative outcome of a co-produced product. The dual role of time use can be positioned as something the consumer wants to minimize for convenient reasons or extended in order to be satisfied with the co-production effort. The paper presents new insights into how co-production and time use influence product evaluation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Bacterial Influences on Animal Origins

PubMed Central

Alegado, Rosanna A.; King, Nicole

2014-01-01

Animals evolved in seas teeming with bacteria, yet the influences of bacteria on animal origins are poorly understood. Comparisons among modern animals and their closest living relatives, the choanoflagellates, suggest that the first animals used flagellated collar cells to capture bacterial prey. The cell biology of prey capture, such as cell adhesion between predator and prey, involves mechanisms that may have been co-opted to mediate intercellular interactions during the evolution of animal multicellularity. Moreover, a history of bacterivory may have influenced the evolution of animal genomes by driving the evolution of genetic pathways for immunity and facilitating lateral gene transfer. Understanding the interactions between bacteria and the progenitors of animals may help to explain the myriad ways in which bacteria shape the biology of modern animals, including ourselves. PMID:25280764

Contextual influence of Taiwanese adolescents' sexual attitudes and behavioral intent.

PubMed

Chen, Angela Chia-Chen; Neilands, Torsten B; Chan, Shu-Min; Lightfoot, Marguerita

2016-09-01

This study examined parental, peer, and media influences on Taiwanese adolescents' attitudes toward premarital sex and intent to engage in sexual behavior. Participants included a convenience sample of 186 adolescents aged 13-15 recruited from two middle schools in Taiwan. Parental influence was indicated by perceived parental disapproval toward premarital sex and perceived peer sexual behavior was used to measure peer influence. Media influence was measured by the adolescents' perception of whether the media promotes premarital sex. We conducted structural equation modeling to test a hypothesized model. The findings suggested that the perceived sexual behavior of peers had the strongest effect on Taiwanese adolescents' sexual attitudes and behavioral intent, while parental disapproval and media influence also significantly contributed to adolescents' sexual attitudes and intent to engage in sex. School nurses are in an ideal position to coordinate essential resources and implement evidence-based sexually transmitted infection and HIV/AIDS prevention interventions that address issues associated with the influence of parents, peers, and media. © 2016 John Wiley & Sons Australia, Ltd.

Depending on My Mood: Mood-Driven Influences on Text Comprehension

PubMed Central

Bohn-Gettler, Catherine M.; Rapp, David N.

2011-01-01

Reading comprehension is a critical component of success in educational settings. To date, research on text processing in educational and cognitive psychological domains has focused predominantly on cognitive influences on comprehension, and in particular, those influences that might be derived from particular tasks or strategies. However, there is growing interest in documenting the influences of emotional factors on the processes and products of text comprehension, because these factors are less likely to be associated with explicit reading strategies. The present study examines this issue by evaluating the degree to which mood can influence readers’ processing of text. Participants in control, happy-induced, or sad-induced groups thought aloud while reading expository texts. Happy, sad, and neutral moods influenced the degree to which readers engaged in particular types of coherence-building processes in the service of comprehension. Although reading strategies clearly influence processing, understudied factors that are less explicitly goal-driven, such as mood, can similarly impact comprehension activity. These findings have important implications for the role of mood on reading instruction and evaluation. PMID:21927504

Structural and Process Factors That Influence Clinical Nurse Specialist Role Implementation.

PubMed

Kilpatrick, Kelley; Tchouaket, Eric; Carter, Nancy; Bryant-Lukosius, Denise; DiCenso, Alba

2016-01-01

The aim of this study was to examine the influence of structure and process on clinical nurse specialist (CNS) role implementation. We conducted a secondary analysis of cross-sectional survey data. The study was performed in Canada. The authors included 445 of 471 questionnaires (94.5%) of graduate-prepared CNSs. Based on Donabedian's framework, we conducted a secondary analysis of CNS responses using hierarchical regression. The internal consistency of the 6 CNS role dimensions and team dynamics subscales was excellent. The use of a framework to guide CNS role implementation influences all the role dimensions. Employer understanding of the CNS role, working in an urban catchment area, specialty certification, and more years in a CNS role had a direct positive influence on team dynamics. Full-time employment exerted a direct negative influence on this dimension. Furthermore, team dynamics (as a mediator variable), seeing patients in practice, and having an office in the clinical unit exerted a direct positive influence on the clinical dimension. Having an annual performance appraisal and a job description exerted a direct negative influence on the clinical dimension. Employer understanding, working in an urban area, full-time employment, and specialty certification had an indirect effect on the clinical dimension. Accountability to a nonnurse manager exerted a direct negative influence on the education dimension. The research and scholarly/professional development dimensions were influenced by more years in a CNS role. Accountability to a nurse manager exerted a direct positive influence on the organizational leadership dimension; unionization and seeing patients in practice had a direct negative influence on this dimension. Seeing patients in practice and full-time employment exerted a direct positive influence on the consultation dimension. The identification of structures and processes that influence CNS role implementation may inform strategies used by

Peer influence on marijuana use in different types of friendships.

PubMed

Tucker, Joan S; de la Haye, Kayla; Kennedy, David P; Green, Harold D; Pollard, Michael S

2014-01-01

Although several social network studies have demonstrated peer influence effects on adolescent substance use, findings for marijuana use have been equivocal. This study examines whether structural features of friendships moderate friends' influence on adolescent marijuana use over time. Using 1-year longitudinal data from the National Longitudinal Study of Adolescent Health, this article examines whether three structural features of friendships moderate friends' influence on adolescent marijuana use: whether the friendship is reciprocated, the popularity of the nominated friend, and the popularity/status difference between the nominated friend and the adolescent. The sample consists of students in grade 10/11 at wave I, who were in grade 11/12 at wave II, from two large schools with complete grade-based friendship network data (N = 1,612). In one school, friends' influence on marijuana use was more likely to occur within mutual, reciprocated friendships compared with nonreciprocated relationships. In the other school, friends' influence was stronger when the friends were relatively popular within the school setting or much more popular than the adolescents themselves. Friends' influence on youth marijuana use may play out in different ways, depending on the school context. In one school, influence occurred predominantly within reciprocated relationships that are likely characterized by closeness and trust, whereas in the other school adopting friends' drug use behaviors appeared to be a strategy to attain social status. Further research is needed to better understand the conditions under which structural features of friendships moderate friends' influence on adolescent marijuana use. Copyright © 2014 Society for Adolescent Health and Medicine. All rights reserved.

Information Dominance: Informations Role in Influencing Decision Making

DTIC Science & Technology

2014-03-01

AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE INFORMATION DOMINANCE : INFORMATION’S ROLE IN INFLUENCING DECISION MAKING 5. FUNDING...unlimited INFORMATION DOMINANCE : INFORMATION’S ROLE IN INFLUENCING DECISION MAKING Geoffrey C. Gaines Lieutenant, United States Navy B.S...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited INFORMATION

The Influence of University Image on Student Behaviour

ERIC Educational Resources Information Center

Alves, Helena; Raposo, Mario

2010-01-01

Purpose: The purpose of this paper is to analyse the influence of image on student satisfaction and loyalty. Design/methodology/approach: In order to accomplish the objectives proposed, a model reflecting the influence of image on student satisfaction and loyalty is applied. The model is tested through use of structural equations and the final…

Peer Influence on Gender Identity Development in Adolescence

ERIC Educational Resources Information Center

Kornienko, Olga; Santos, Carlos E.; Martin, Carol Lynn; Granger, Kristen L.

2016-01-01

During adolescence, gender identity (GI) develops through a dialectic process of personal reflection and with input from the social environment. Peers play an important role in the socialization of gendered behavior, but no studies to-date have assessed peer influences on GI. Thus, the goal of the present study was to examine peer influences on…

Influencing Organizations to Promote Health: Applying Stakeholder Theory

ERIC Educational Resources Information Center

Kok, Gerjo; Gurabardhi, Zamira; Gottlieb, Nell H.; Zijlstra, Fred R. H.

2015-01-01

Stakeholder theory may help health promoters to make changes at the organizational and policy level to promote health. A stakeholder is any individual, group, or organization that can influence an organization. The organization that is the focus for influence attempts is called the focal organization. The more salient a stakeholder is and the more…

Factors That Influence Technology Integration in the Classroom

ERIC Educational Resources Information Center

Montgomery, Maureen C.

2017-01-01

Education is one area where the use of technology has had great impact on student learning. The integration of technology in teaching and learning can significantly influence the outcome of education in the classroom. However, there are a myriad of factors that influence technology integration in the classroom. The purpose of this study was to…

Family and School Influences on Adolescent Smoking Behaviour

ERIC Educational Resources Information Center

Wiium, Nora; Wold, Bente

2006-01-01

Purpose: This paper aims to examine how influences at home and school interact to predict smoking among adolescents. Design/methodology/approach: Data were collected from 15-year-old pupils from Norway (n=1,404 in 73 Grade 10 school classes). Multilevel logistic regression analysis was used to determine how family and school influences interact to…

Factors influencing the, selection of state office furniture

Treesearch

R. Bruce Anderson; R. Bruce Anderson

1973-01-01

Evaluation of the factors influencing the selection of office furniture by nine state governments shows that quality and purchase price have the most important influence on the purchase decision. The intended use of the furniture and the purchasing regulations of the states were key f8CbrS in the use of wood furniture.

Gubernatorial Authority and Influence on Public Higher Education

ERIC Educational Resources Information Center

Christakis, Michael N.

2009-01-01

State governors have the potential to impact their states' public higher education systems in a variety of very significant ways. The findings for the 33 governors included in this study suggest a great deal of variation in the extent of their authority and influence. Governors' composite ratings of formal authority and informal influence are…

Sociocultural Influences on Psychosocial Adjustment in Antarctica

DTIC Science & Technology

1985-12-01

od-; SOCIOCULTURAL INFLUENCES ON PSYCHOSOCIAL ADJUSTMENT IN ANTARCTICA L. A. PALINKAS 00 00 ’n REPORT NO. 85-49 D I MAR ~3 11986 L) L O~flN STAnTEMN...A Apprtoved 6Wz PUbli reIl. NAVAL HEALTH RESEARCH CENTER P.O. BOX 85122 0 SAN DIEGO, CALIFORNIA 92138-9174 --j NAVAL MEDICAL RESEARCH AND DEVELOPMENT ...COMMAND LJ6. BETHESDA, MARYLAND SOCIOCULTURAL INFLUENCES ON PSYCHOSOCIAL ADJUSTMENT IN ANTARCTICA Lawrence A. Palinkas, Ph.D. Manager, Psychiatric

Developmental changes in coping: situational and methodological influences.

PubMed

Vierhaus, Marc; Lohaus, Arnold; Ball, Juliane

2007-09-01

Previous studies on the development of coping have shown rather inconsistent findings regarding the developmental trajectories for different coping dimensions. The aim of this study is to search for possible influences that might explain these inconsistencies. The analysis focuses on methodological influences (longitudinal vs. cross-sectional assessments) and situational influences. Two samples of children were traced longitudinally with yearly assessments from grade 2 to 5 (sample 1, N =432) and from grade 4 to 7 (sample 2, N =366). A third sample (N =849) was added with cross-sectional assessments from grade 2 to 7. The assessed coping dimensions were related to (a) problem solving, (b) seeking social support, (c) palliative coping, (d) externalizing emotional coping, and (e) avoidant coping. The use of the coping strategies had to be assessed for six stress-evoking situations. The results show only small differences between the longitudinal and the cross-sectional coping assessments. There are, however, clear situational influences on the choice of the coping strategies and also on the resulting developmental trajectories.

Peer influence processes for youth delinquency and depression.

PubMed

Reynolds, Andrew D; Crea, Thomas M

2015-08-01

This study explores the multiple factors that account for peer influence processes of adolescent delinquency and depression using data from Waves I and II of the National Longitudinal Study of Adolescent to Adult Health (Add Health). Random-effects longitudinal negative binomial models were used to predict depression and delinquency, controlling for social connection variables to account for selection bias. Findings suggest peer depression and delinquency are both predictive of youth delinquency, while peer influences of depression are much more modest. Youth who are more connected to parents and communities and who are more popular within their networks are more susceptible to peer influence, while self-regulating youth are less susceptible. We find support for theories of popularity-socialization as well as weak-ties in explaining social network factors that amplify or constrain peer influence. We argue that practitioners working with youth should consider network-informed interventions to improve program efficacy and avoid iatrogenic effects. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

The influence of unimanual response on pseudoneglect magnitude.

PubMed

McCourt, M E; Freeman, P; Tahmahkera-Stevens, C; Chaussee, M

2001-02-01

Various factors influence the degree of leftward error (pseudoneglect) (Bowers & Heilman, 1980) that typifies the performance of normal subjects in line bisection tasks (Jewell & McCourt, 2000). The results of this experiment show that unimanual responding also exerts a subtle but significant modulating influence on spatial attention, as indexed by the differential magnitude of pseudoneglect. Using a forced-choice tachistoscopic line bisection protocol, 184 subjects (92 male and 92 female) bisected horizontally oriented lines (22.3 degrees wide x 0.39 degrees height) presented to central vision in two conditions, in which bisection responses were executed via button presses using the first two fingers of either the left (LH) or right (RH) hand. Perceived line midpoint deviated significantly leftward of veridical (p <.05) in both conditions. There was no significant influence of subject sex (p >.05). A significant influence of unimanual response was revealed (p <.05) where pseudoneglect magnitude was greater in the LH than the RH condition. The results are interpreted within the framework of the activation-orientation theory of attentional asymmetry. Copyright 2001 Academic Press.

Cross-correlations and influence in world gold markets

NASA Astrophysics Data System (ADS)

Lin, Min; Wang, Gang-Jin; Xie, Chi; Stanley, H. Eugene

2018-01-01

Using the detrended cross-correlation analysis (DCCA) coefficient and the detrended partial cross-correlation analysis (DPCCA) coefficient, we investigate cross-correlations and net cross-correlations among five major world gold markets (London, New York, Shanghai, Tokyo, and Mumbai) at different time scales. We propose multiscale influence measures for examining the influence of individual markets on other markets and on the entire system. We find (i) that the cross-correlations, net cross-correlations, and net influences among the five gold markets vary across time scales, (ii) that the cross-market correlation between London and New York at each time scale is intense and inherent, meaning that the influence of other gold markets on the London-New York market is negligible, (iii) that the remaining cross-market correlations (i.e., those other than London-New York) are greatly affected by other gold markets, and (iv) that the London gold market significantly affects the other four gold markets and dominates the world-wide gold market. Our multiscale findings give market participants and market regulators new information on cross-market linkages in the world-wide gold market.

Influence of radiation on metastability-based TRNG

NASA Astrophysics Data System (ADS)

Wieczorek, Piotr Z.; Wieczorek, Zbigniew

2017-08-01

This paper presents a True Random Number Generator (TRNG) based on Flip-Flops with violated timing constraints. The proposed circuit has been implemented in a Xilinx Spartan 6 device. The TRNG circuit utilizes the metastability phenomenon as a source of randomness. Therefore, in the paper the influence of timing constraints on the flip-flop metastability proximity is discussed. The metastable range of operation enhances the noise influence on a Flip-Flop behavior. Therefore, the influence of an external stochastic source on the flip-flop operation is also investigated. For this purpose a radioactive source of radiation was used. According to the results shown in the paper the radiation increases the unpredictability of the metastable process of flip-flops operating as the randomness source in the TRNG. The statistical properties of TRNG operating in an increased radiation conditions were verified with the NIST battery of statistical tests.

Wind influence on a coastal buoyant outflow

NASA Astrophysics Data System (ADS)

Whitney, Michael M.; Garvine, Richard W.

2005-03-01

This paper investigates the interplay between river discharge and winds in forcing coastal buoyant outflows. During light winds a plume influenced by the Earth's rotation will flow down shelf (in the direction of Kelvin wave propagation) as a slender buoyancy-driven coastal current. Downwelling favorable winds augment this down-shelf flow, narrow the plume, and mix the water column. Upwelling favorable winds drive currents that counter the buoyancy-driven flow, spread plume waters offshore, and rapidly mix buoyant waters. Two criteria are developed to assess the wind influence on a buoyant outflow. The wind strength index (Ws) determines whether a plume's along-shelf flow is in a wind-driven or buoyancy-driven state. Ws is the ratio of the wind-driven and buoyancy-driven along-shelf velocities. Wind influence on across-shelf plume structure is rated with a timescale (ttilt) for the isopycnal tilting caused by wind-driven Ekman circulation. These criteria are used to characterize wind influence on the Delaware Coastal Current and can be applied to other coastal buoyant outflows. The Delaware buoyant outflow is simulated for springtime high-river discharge conditions. Simulation results and Ws values reveal that the coastal current is buoyancy-driven most of the time (∣Ws∣ < 1 on average). Wind events, however, overwhelm the buoyancy-driven flow (∣Ws∣ > 1) several times during the high-discharge period. Strong upwelling events reverse the buoyant outflow; they constitute an important mechanism for transporting fresh water up shelf. Across-shelf plume structure is more sensitive to wind influence than the along-shelf flow. Values of ttilt indicate that moderate or strong winds persisting throughout a day can modify plume width significantly. Plume widening during upwelling events is accompanied by mixing that can erase the buoyant outflow.

Undergraduate experience of surgical teaching and its influence and its influence on career choice.

PubMed

Ek, Edmund W; Ek, Eugene T; Mackay, Sean D

2005-08-01

The purpose of this survey was to determine the views of final year medical students in Melbourne regarding both undergraduate surgical teaching and the students' career aspirations. A structured questionnaire was given to all final year medical students at Monash and Melbourne Universities in 2003. The questions dealt with the factors influencing graduating medical students, including theatre experience, encouragement/support from surgeons, presence of mentors, lifestyle factors and gender issues. The response rate was 61.2% (251/410). Of these, 50.6% were male, 32.3% declared an interest in surgical training with the remainder either uncertain (24%) or uninterested (44%). Male students were more likely to be interested in surgery. General surgery was the most popular field (69%), followed by plastic surgery (37%) and orthopaedic surgery (35%). Of respondents, 78% reported positive influences towards pursuing a surgical career during their undergraduate years, while 63% reported a negative experience. A total of 67% believed that the current curriculum is adequate and 43% that there is enough support/encouragement towards a surgical career. Only 44% of respondents reported that surgeons are approachable. Lifestyle and family factors were the most important career influence. In particular, 57% of female respondents felt discouraged from pursuing a surgical career and 99% of these women reported lifestyle/family factors as the main source of discouragement, with a further 72% identifying a lack of female role models. This survey highlights important issues in current undergraduate perception of surgical teaching and higher training. Issues that may encourage or discourage a graduating student to pursue a surgical career are identified.

State legislative staff influence in health policy making.

PubMed

Weissert, C S; Weissert, W G

2000-12-01

State legislative staff may influence health policy by gathering intelligence, setting the agenda, and shaping the legislative proposals. But they may also be stymied in their roles by such institutional constraints as hiring practices and by turnover in committee leadership in the legislature. The intervening variable of trust between legislators and their support staff is also key to understanding influence and helps explain how staff-legislator relationships play an important role in designing state health policy. This study of legislative fiscal and health policy committee staff uses data from interviews with key actors in five states to model the factors important in explaining variation in the influence of committee staff on health policy.

AUI&GIV: Recommendation with Asymmetric User Influence and Global Importance Value

PubMed Central

Zhao, Zhi-Lin; Wang, Chang-Dong; Lai, Jian-Huang

2016-01-01

The user-based collaborative filtering (CF) algorithm is one of the most popular approaches for making recommendation. Despite its success, the traditional user-based CF algorithm suffers one serious problem that it only measures the influence between two users based on their symmetric similarities calculated by their consumption histories. It means that, for a pair of users, the influences on each other are the same, which however may not be true. Intuitively, an expert may have an impact on a novice user but a novice user may not affect an expert at all. Besides, each user may possess a global importance factor that affects his/her influence to the remaining users. To this end, in this paper, we propose an asymmetric user influence model to measure the directed influence between two users and adopt the PageRank algorithm to calculate the global importance value of each user. And then the directed influence values and the global importance values are integrated to deduce the final influence values between two users. Finally, we use the final influence values to improve the performance of the traditional user-based CF algorithm. Extensive experiments have been conducted, the results of which have confirmed that both the asymmetric user influence model and global importance value play key roles in improving recommendation accuracy, and hence the proposed method significantly outperforms the existing recommendation algorithms, in particular the user-based CF algorithm on the datasets of high rating density. PMID:26828803

AUI&GIV: Recommendation with Asymmetric User Influence and Global Importance Value.

PubMed

Zhao, Zhi-Lin; Wang, Chang-Dong; Lai, Jian-Huang

2016-01-01

The user-based collaborative filtering (CF) algorithm is one of the most popular approaches for making recommendation. Despite its success, the traditional user-based CF algorithm suffers one serious problem that it only measures the influence between two users based on their symmetric similarities calculated by their consumption histories. It means that, for a pair of users, the influences on each other are the same, which however may not be true. Intuitively, an expert may have an impact on a novice user but a novice user may not affect an expert at all. Besides, each user may possess a global importance factor that affects his/her influence to the remaining users. To this end, in this paper, we propose an asymmetric user influence model to measure the directed influence between two users and adopt the PageRank algorithm to calculate the global importance value of each user. And then the directed influence values and the global importance values are integrated to deduce the final influence values between two users. Finally, we use the final influence values to improve the performance of the traditional user-based CF algorithm. Extensive experiments have been conducted, the results of which have confirmed that both the asymmetric user influence model and global importance value play key roles in improving recommendation accuracy, and hence the proposed method significantly outperforms the existing recommendation algorithms, in particular the user-based CF algorithm on the datasets of high rating density.

Measuring the Ways Significant Persons Influence Attitudes Towards Science and Mathematics

NASA Astrophysics Data System (ADS)

Sjaastad, Jørgen

2013-01-01

Young people's attitudes towards science, technology, engineering, and mathematics (STEM) are subject to interpersonal influence of significant persons-defined as those who influence a person's attitudes. This article presents the development of an instrument designed to measure different modes of significant persons' influence on attitudes towards STEM. The questionnaire used in the pilot study was compiled based on Woelfel and Haller's theoretical perspectives on interpersonal influence, Nauta and Kokaly's instrument Influence of Others on Academic and Career Decisions Scale, and focus group interviews with Norwegian adolescents in an STEM mentoring programme. Drawing on Rasch analyses of data material from the 114 participants in the pilot study, the final instrument-Significant Person Influence on Attitudes towards STEM (SPIAS)-is presented. Based on results from the piloting and development of SPIAS, a conceptual discussion of significant persons and the ways they influence attitudes towards STEM is given, and it is suggested that SPIAS may be used in the process of evaluating and improving interventions aimed at changing adolescents' attitudes towards STEM.

Differentiation without distancing. explaining bi-polarization of opinions without negative influence.

PubMed

Mäs, Michael; Flache, Andreas

2013-01-01

Explanations of opinion bi-polarization hinge on the assumption of negative influence, individuals' striving to amplify differences to disliked others. However, empirical evidence for negative influence is inconclusive, which motivated us to search for an alternative explanation. Here, we demonstrate that bi-polarization can be explained without negative influence, drawing on theories that emphasize the communication of arguments as central mechanism of influence. Due to homophily, actors interact mainly with others whose arguments will intensify existing tendencies for or against the issue at stake. We develop an agent-based model of this theory and compare its implications to those of existing social-influence models, deriving testable hypotheses about the conditions of bi-polarization. Hypotheses were tested with a group-discussion experiment (N = 96). Results demonstrate that argument exchange can entail bi-polarization even when there is no negative influence.

Differentiation without Distancing. Explaining Bi-Polarization of Opinions without Negative Influence

PubMed Central

Mäs, Michael; Flache, Andreas

2013-01-01

Explanations of opinion bi-polarization hinge on the assumption of negative influence, individuals’ striving to amplify differences to disliked others. However, empirical evidence for negative influence is inconclusive, which motivated us to search for an alternative explanation. Here, we demonstrate that bi-polarization can be explained without negative influence, drawing on theories that emphasize the communication of arguments as central mechanism of influence. Due to homophily, actors interact mainly with others whose arguments will intensify existing tendencies for or against the issue at stake. We develop an agent-based model of this theory and compare its implications to those of existing social-influence models, deriving testable hypotheses about the conditions of bi-polarization. Hypotheses were tested with a group-discussion experiment (N = 96). Results demonstrate that argument exchange can entail bi-polarization even when there is no negative influence. PMID:24312164

INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

EPA Science Inventory

The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator_¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

Wittrock's Influence on Mathematics Education: Some Personal Comments

ERIC Educational Resources Information Center

Romberg, Thomas A.

2010-01-01

Merlin C. Wittrock was a friend and colleague who influenced me and many other contemporary mathematics educators on how students learn. In this article I summarize my interactions with Merl beginning in 1965, and how over the following half-century he influenced my thinking on student learning for understanding and, in turn, on how to design…

How the Economy Influences Pedagogy: The Great Recession's Influence on Elementary Teaching Practices

ERIC Educational Resources Information Center

Sawyer, Amanda G.

2017-01-01

From 2007 to 2009, the United States experienced one of the greatest economic declines reported in the previous decades, known as the Great Recession (Bureau of Labor Statistics, 2012). While a great deal of media attention focused on the immediate financial effects of the recession, little discussion was made about the influence of this crisis…

Anxiety as a factor influencing physiological effects of acupuncture.

PubMed

Vickland, Victor; Rogers, Carole; Craig, Ashley; Tran, Yvonne

2009-08-01

This study investigated the influence of manual acupuncture on heart rate variability and the role which anxiety can play in modifying physiological outcomes. Analysis of heart rate variability (HRV) was used as a sensitive and a reliable indicator of the balance between sympathetic and parasympathetic regulation of the heartbeat. Two groups of healthy female subjects were recruited into the study. The control group (n=30) attended one experimental session where no acupuncture treatment was used. The experimental group (n=30) attended three sessions in which unilateral manual stimulation of acupuncture points LU7 and KD6 was performed. The stimulation of the acupuncture points LU7 and KD6 was not associated with significant changes in HRV. Previous familiarity with acupuncture did not influence the outcomes but level of anxiety had a strong impact on physiological outcomes. Stimulation of LU7 acupuncture point counterbalanced naturally occurring sympathetic increase over time and had relaxing and harmonizing effect on the heart rhythm without influencing subjective perception of increased anxiety. Stimulation of KD6 acupuncture point had sympathetic influence on HRV in subjects with low "trait" anxiety and this influence was nullified by simultaneous stimulation of LU7 acupuncture point. It seems likely that the level of anxiety can modify HRV during acupuncture treatment and up to 40 min after the treatment. Psychological factors such as anxiety level should be considered as having important influence on physiological response to acupuncture.

Influence of pharmaceutical marketing on prescription practices of physicians.

PubMed

Narendran, Roshni; Narendranathan, M

2013-01-01

In India same drug molecules are sold under different brand names by different pharmaceuticals. To persuade the physicians to prescribe their brands pharmaceuticals engage in marketing techniques like giving samples, gifts, sponsoring travel etc. Many countries are striving to reduce the impact of incentives on prescription behaviour. This study explores the influence of pharmaceutical marketing on the prescription practices of doctors in India. There were 103 study subjects - 50 doctors and 53 sales personnel. Data collection was done by a self administered questionnaire. Data were collected on 36 variables which were supposed to influence prescription. The effectiveness of the promotional strategies on prescription behaviour was marked in a seven point Likert scale ranging from "not at all effective" (score=1) to "extremely effective" (score=7). Open ended questions were used to collect qualitative data. Good rapport with the doctor, launch meetings, reputation of the company, quality of the drug and brand names significantly influenced prescription behaviour, while direct mailers, advertisements in journals and giving letter pads and other brand reminders were less effective. Commonly used method of giving samples was not among the twenty most effective methods influencing prescription. Product quality and good company are still factors that influence prescription. Pharmaceutical marketing influences the choice of brands by a physician. The more expensive strategies involved in public relations are more effective. Sending mails and journal advertisements are less effective strategies. How expensive marketing strategies affect cost of the medicines has to be explored further.

The Influence of Judgment Calls on Meta-Analytic Findings.

PubMed

Tarrahi, Farid; Eisend, Martin

2016-01-01

Previous research has suggested that judgment calls (i.e., methodological choices made in the process of conducting a meta-analysis) have a strong influence on meta-analytic findings and question their robustness. However, prior research applies case study comparison or reanalysis of a few meta-analyses with a focus on a few selected judgment calls. These studies neglect the fact that different judgment calls are related to each other and simultaneously influence the outcomes of a meta-analysis, and that meta-analytic findings can vary due to non-judgment call differences between meta-analyses (e.g., variations of effects over time). The current study analyzes the influence of 13 judgment calls in 176 meta-analyses in marketing research by applying a multivariate, multilevel meta-meta-analysis. The analysis considers simultaneous influences from different judgment calls on meta-analytic effect sizes and controls for alternative explanations based on non-judgment call differences between meta-analyses. The findings suggest that judgment calls have only a minor influence on meta-analytic findings, whereas non-judgment call differences between meta-analyses are more likely to explain differences in meta-analytic findings. The findings support the robustness of meta-analytic results and conclusions.

Factors influencing pacing in triathlon

PubMed Central

Wu, Sam SX; Peiffer, Jeremiah J; Brisswalter, Jeanick; Nosaka, Kazunori; Abbiss, Chris R

2014-01-01

Triathlon is a multisport event consisting of sequential swim, cycle, and run disciplines performed over a variety of distances. This complex and unique sport requires athletes to appropriately distribute their speed or energy expenditure (ie, pacing) within each discipline as well as over the entire event. As with most physical activity, the regulation of pacing in triathlon may be influenced by a multitude of intrinsic and extrinsic factors. The majority of current research focuses mainly on the Olympic distance, whilst much less literature is available on other triathlon distances such as the sprint, half-Ironman, and Ironman distances. Furthermore, little is understood regarding the specific physiological, environmental, and interdisciplinary effects on pacing. Therefore, this article discusses the pacing strategies observed in triathlon across different distances, and elucidates the possible factors influencing pacing within the three specific disciplines of a triathlon. PMID:25258562

Lifetime influences for cannabis cessation in male incarcerated indigenous australians.

PubMed

Jacups, Susan; Rogerson, Bernadette

2015-01-01

Urban non-indigenous populations report life events (marriages, employment) as influences for self-initiated cannabis cessation. However, this hasn't been investigated in remote indigenous populations with different social paradigms. We investigate cannabis use, harms, and poly-substance misuse in 101 consenting male incarcerated indigenous Australians. Interviews applied quantitative and qualitative questions assessing demographic characteristics, criminal history, drug use, the Marijuana Problems Inventory (MPI), and cannabis-cessation influences. Comparisons used Chi Square, Analysis of Variance, and Nvivo software. Cannabis use groups (current users, ex-users, and never users) were demographically similar except that current users reported more juvenile legal problems, younger school departure, and lower school achievement (p < 0.05). Mean cannabis consumption was 12.3 cones/day. Incarceration and family responsibilities were the strongest cessation influences. Employment responsibilities and negative self-image were rarely cited as influences. High cannabis use, with its associated problems, is concerning. These identified influences indicate incarceration should be used for substance reduction programs, plus post-release follow-up. Community-based programs focusing on positive influences, such as family responsibilities and social cohesion, may be successful within indigenous populations with strong kinship responsibilities, rather than programs that focus solely on substance harms.

Sources of influence on infant feeding practices in Hong Kong.

PubMed

Hung, B K; Ling, L; Ong, S G

1985-01-01

The breastfeeding rate in Hong Kong is low compared to the rates in Western countries. To understand the relative importance of different sources of influence on infant feeding practices, 714 Chinese mothers with infants aged 4 weeks to 6 months were studied. It was found that the bottlefeeding mothers were influenced more by the medical professionals who did not support breastfeeding. This influence was further reinforced by the mass media and particularly television advertisements on infant formulae. The successful breastfeeding mothers, on the other hand, were influenced more by their social networks through which they were told of the dangers of bottlefeeding. The failed breastfeeding mothers differed from the other groups in the lack of support they experienced from friends and relatives. Although they received professional encouragement to breastfeed, they were more sheltered from the influence of mass media and social networks. From these findings, it is suggested that different sources of influence are related to different feeding practices. However, to be able to continue with the practice that one has chosen, the availability of social support is essential. Implications of these findings are discussed and several recommendations to promote breastfeeding are made.

A review of family meal influence on adolescents' dietary intake.

PubMed

Woodruff, Sarah J; Hanning, Rhona M

2008-01-01

Recent concerns about adolescent nutrition and unhealthy weights have prompted an examination of the myriad influences on dietary intake during adolescence. Included here are a summary of the literature on family influence on dietary intake, specifically during adolescence and within the family context, a summary of family meal patterns, and a systematic review of the known influences of family meals on dietary intake. Because of the complexity of families in today's society, models were developed to depict the broad context of familial influences on adolescent nutritional behaviours and attitudes and to describe what is known and not known about family meal influences on adolescent dietary intake and quality. A systematic review of the literature revealed seven articles specifically related to adolescents, family meals, and dietary intake, which were analyzed for strength of evidence and plausibility. In spite of data collection methods relying on self-report, results suggested that family meals were associated with improved dietary intakes. Families in today's societies are complex. Nevertheless, parents have the potential to influence positively, through family meals, what food is provided, where it is provided (e.g., home, restaurant), and within what type of atmosphere it is provided.

Social Influence on Positive Youth Development: A Developmental Neuroscience Perspective.

PubMed

Telzer, Eva H; van Hoorn, Jorien; Rogers, Christina R; Do, Kathy T

2018-01-01

Susceptibility to social influence is associated with a host of negative outcomes during adolescence. However, emerging evidence implicates the role of peers and parents in adolescents' positive and adaptive adjustment. Hence, in this chapter we highlight social influence as an opportunity for promoting social adjustment, which can redirect negative trajectories and help adolescents thrive. We discuss influential models about the processes underlying social influence, with a particular emphasis on internalizing social norms, embedded in social learning and social identity theory. We link this behavioral work to developmental social neuroscience research, rooted in neurobiological models of decision making and social cognition. Work from this perspective suggests that the adolescent brain is highly malleable and particularly oriented toward the social world, which may account for heightened susceptibility to social influences during this developmental period. This chapter underscores the need to leverage social influences during adolescence, even beyond the family and peer context, to promote positive developmental outcomes. By further probing the underlying neural mechanisms as an additional layer to examining social influence on positive youth development, we will be able to gain traction on our understanding of this complex phenomenon. © 2018 Elsevier Inc. All rights reserved.

Cells, circuits, and choices: social influences on perceptual decision making.

PubMed

Mojzisch, Andreas; Krug, Kristine

2008-12-01

Making decisions is an integral part of everyday life. Social psychologists have demonstrated in many studies that humans' decisions are frequently and strongly influenced by the opinions of others--even in simple perceptual decisions, where, for example, participants have to judge what an image looks like. However, because the effect of other people's opinions on decision making has remained largely unaddressed by the neuroimaging and neurophysiology literature, we are only beginning to understand how social influence is integrated into the decision-making process. We put forward the thesis that by probing the neurophysiology of social influence with perceptual decision-making tasks similar to those used in the seminal work of Asch (1952, 1956), this gap could be remedied. Perceptual paradigms are already widely used to probe neuronal mechanisms of decision making in nonhuman primates. There is also increasing evidence about how nonhuman primates' behavior is influenced by observing conspecifics. The high spatial and temporal resolution of neurophysiological recordings in awake monkeys could provide insight into where and how social influence modulates decision making, and thus should enable us to develop detailed functional models of the neural mechanisms that support the integration of social influence into the decision-making process.

Automated generation of influence functions for planar crack problems

NASA Technical Reports Server (NTRS)

Sire, Robert A.; Harris, David O.; Eason, Ernest D.

1989-01-01

A numerical procedure for the generation of influence functions for Mode I planar problems is described. The resulting influence functions are in a form for convenient evaluation of stress-intensity factors for complex stress distributions. Crack surface displacements are obtained by a least-squares solution of the Williams eigenfunction expansion for displacements in a cracked body. Discrete values of the influence function, evaluated using the crack surface displacements, are curve fit using an assumed functional form. The assumed functional form includes appropriate limit-behavior terms for very deep and very shallow cracks. Continuous representation of the influence function provides a convenient means for evaluating stress-intensity factors for arbitrary stress distributions by numerical integration. The procedure is demonstrated for an edge-cracked strip and a radially cracked disk. Comparisons with available published results demonstrate the accuracy of the procedure.

Physiological stress response to loss of social influence and threats to masculinity.

PubMed

Taylor, Catherine J

2014-02-01

Social influence is an important component of contemporary conceptualizations of masculinity in the U.S. Men who fail to achieve masculinity by maintaining social influence in the presence of other men may be at risk of stigmatization. As such, men should be especially likely to exhibit a stress response to loss of social influence in the presence of other men. This study assesses whether men who lose social influence exhibit more of a stress response than men who gain social influence, using data collected in a laboratory setting where participants were randomly assigned into four-person groups of varying sex compositions. The groups were videotaped working on two problem-solving tasks. Independent raters assessed change in social influence using a well-validated measure borrowed from experimental work in the Status Characteristics Theory tradition. Cortisol is used as a measure of stress response because it is known to increase in response to loss of social esteem. Results show that young men who lose social influence while working with other young men exhibit cortisol response. In contrast women do not exhibit cortisol response to loss of social influence, nor do men working with women. Results are consistent with the hypothesis that loss of social influence in men may be associated with a physiological stress response because maintaining social influence is very important to men while in the presence of other men. This physiological response to loss of social influence underscores the importance to men of achieving masculinity through gaining and maintaining social influence, and avoiding the stigma associated with the failure to do so. Copyright © 2013 Elsevier Ltd. All rights reserved.

Social Influences on Abstinence Self-Efficacy among Justice-Involved Persons

PubMed Central

Majer, John M.; Callahan, Sarah; Stevick, Kate; Jason, Leonard A.

2016-01-01

Social influences (social support for alcohol/drug use and social support for abstinence) were examined in relation to abstinence self-efficacy among a sample of 250 justice involved persons exiting inpatient treatment for substance use disorders. Hierarchical linear regression was used to examine social influences in relation to abstinence self-efficacy. Social influences were significantly related to abstinence self-efficacy when examined independently. However, only social support for alcohol/drug use was significant when both social influences were entered into the model. Findings suggest social support for alcohol/drug use compromises abstinence social support, particularly among justice involved persons who are early in their recovery from substance use disorders. PMID:27594810

[The influence of electromagnetic fields on flora and fauna].

PubMed

Rochalska, Małgorzata

2009-01-01

This paper presents the influence of natural and artificial electromagnetic fields (EMF) on fauna and flora. The mechanisms of Earth's magnetic field detection and the use of this skill by migratory animals to faultlessly reach the destination of their travel are discussed, as well as the positive effects of electric and magnetic fields on plants relative to their physiology, yielding and health. EMF influence on social insects and animal organisms, including possible DNA damages and DNA repair systems, is presented. The influence of high frequency electromagnetic fields on birds nesting is also discussed.

Does changing social influence engender changes in alcohol intake? A meta-analysis.

PubMed

Prestwich, Andrew; Kellar, Ian; Conner, Mark; Lawton, Rebecca; Gardner, Peter; Turgut, Liz

2016-10-01

Past research has suggested that social influences on drinking can be manipulated with subsequent reductions in alcohol intake. However, the experimental evidence for this and the best strategies to positively change these social influences have not been meta-analyzed. This research addressed these gaps. Randomized controlled trials testing social influence-based interventions on adults' drinking were systematically reviewed and meta-analyzed. The behavior change techniques used in each study were coded and the effect sizes showing the impact of each intervention on (a) social influence and (b) alcohol intake were calculated. Metaregressions identified the association between these effect sizes, as well as the effect of specific behavior change techniques on social influences. Forty-one studies comprising 17,445 participants were included. Changes in social influences were significantly associated with changes in alcohol intake. However, even moderate-to-large changes in social influences corresponded with only a small change in drinking behavior and changing social influences did not reduce alcohol-related problems. Providing normative information about others' behavior and experiences was the most effective technique to change social influences. Social influences and normative beliefs can be changed in drinkers, particularly by providing normative information about how much others' drink. However, even generating large changes in these constructs are likely to engender only small changes in alcohol intake. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Bully Victimization: Selection and Influence Within Adolescent Friendship Networks and Cliques.

PubMed

Lodder, Gerine M A; Scholte, Ron H J; Cillessen, Antonius H N; Giletta, Matteo

2016-01-01

Adolescents tend to form friendships with similar peers and, in turn, their friends further influence adolescents' behaviors and attitudes. Emerging work has shown that these selection and influence processes also might extend to bully victimization. However, no prior work has examined selection and influence effects involved in bully victimization within cliques, despite theoretical account emphasizing the importance of cliques in this regard. This study examined selection and influence processes in adolescence regarding bully victimization both at the level of the entire friendship network and the level of cliques. We used a two-wave design (5-month interval). Participants were 543 adolescents (50.1% male, Mage = 15.8) in secondary education. Stochastic actor-based models indicated that at the level of the larger friendship network, adolescents tended to select friends with similar levels of bully victimization as they themselves. In addition, adolescent friends influenced each other in terms of bully victimization over time. Actor Parter Interdependence models showed that similarities in bully victimization between clique members were not due to selection of clique members. For boys, average clique bully victimization predicted individual bully victimization over time (influence), but not vice versa. No influence was found for girls, indicating that different mechanisms may underlie friend influence on bully victimization for girls and boys. The differences in results at the level of the larger friendship network versus the clique emphasize the importance of taking the type of friendship ties into account in research on selection and influence processes involved in bully victimization.

Nucleosomes influence multiple steps during replication initiation

PubMed Central

Azmi, Ishara F; Watanabe, Shinya; Maloney, Michael F; Kang, Sukhyun; Belsky, Jason A; MacAlpine, David M; Peterson, Craig L; Bell, Stephen P

2017-01-01

Eukaryotic replication origin licensing, activation and timing are influenced by chromatin but a mechanistic understanding is lacking. Using reconstituted nucleosomal DNA replication assays, we assessed the impact of nucleosomes on replication initiation. To generate distinct nucleosomal landscapes, different chromatin-remodeling enzymes (CREs) were used to remodel nucleosomes on origin-DNA templates. Nucleosomal organization influenced two steps of replication initiation: origin licensing and helicase activation. Origin licensing assays showed that local nucleosome positioning enhanced origin specificity and modulated helicase loading by influencing ORC DNA binding. Interestingly, SWI/SNF- and RSC-remodeled nucleosomes were permissive for origin licensing but showed reduced helicase activation. Specific CREs rescued replication of these templates if added prior to helicase activation, indicating a permissive chromatin state must be established during origin licensing to allow efficient origin activation. Our studies show nucleosomes directly modulate origin licensing and activation through distinct mechanisms and provide insights into the regulation of replication initiation by chromatin. DOI: http://dx.doi.org/10.7554/eLife.22512.001 PMID:28322723

Using Network Dynamical Influence to Drive Consensus

NASA Astrophysics Data System (ADS)

Punzo, Giuliano; Young, George F.; MacDonald, Malcolm; Leonard, Naomi E.

2016-05-01

Consensus and decision-making are often analysed in the context of networks, with many studies focusing attention on ranking the nodes of a network depending on their relative importance to information routing. Dynamical influence ranks the nodes with respect to their ability to influence the evolution of the associated network dynamical system. In this study it is shown that dynamical influence not only ranks the nodes, but also provides a naturally optimised distribution of effort to steer a network from one state to another. An example is provided where the “steering” refers to the physical change in velocity of self-propelled agents interacting through a network. Distinct from other works on this subject, this study looks at directed and hence more general graphs. The findings are presented with a theoretical angle, without targeting particular applications or networked systems; however, the framework and results offer parallels with biological flocks and swarms and opportunities for design of technological networks.

Modeling of Internet Influence on Group Emotion

NASA Astrophysics Data System (ADS)

Czaplicka, Agnieszka; Hołyst, Janusz A.

Long-range interactions are introduced to a two-dimensional model of agents with time-dependent internal variables ei = 0, ±1 corresponding to valencies of agent emotions. Effects of spontaneous emotion emergence and emotional relaxation processes are taken into account. The valence of agent i depends on valencies of its four nearest neighbors but it is also influenced by long-range interactions corresponding to social relations developed for example by Internet contacts to a randomly chosen community. Two types of such interactions are considered. In the first model the community emotional influence depends only on the sign of its temporary emotion. When the coupling parameter approaches a critical value a phase transition takes place and as result for larger coupling constants the mean group emotion of all agents is nonzero over long time periods. In the second model the community influence is proportional to magnitude of community average emotion. The ordered emotional phase was here observed for a narrow set of system parameters.

Tobacco Industry Influences in the Oklahoma Legislature.

PubMed

Matheny, James D; Wagener, Theodore L; Anderson, Michael P

2015-11-01

To identify recent tobacco industry influences in the Oklahoma Legislature. Relevant public records were compiled and published online in searchable databases. Activities related to two contested tobacco-related legislative initiatives were analyzed. Analyses of voting behavior controlled for party affiliation. Legislators receiving the largest amounts of campaign contributions and gifts from tobacco lobbyists performed actions necessary to advance tobacco industry objectives. Several significant associations with voting behavior were observed, the strongest of which was between votes on a pro-tobacco industry bill and gifts from tobacco lobbyists. Most lobbyists'gifts were meals. Tobacco industry influence in the Oklahoma Legislature is enhanced through tobacco lobbyists' campaign contributions and gifts. Greater investments are made in legislative leaders, those serving as champions or spokespersons, and others taking key roles in advancing tobacco industry objectives. Exposing such influences may diminish their effects. Given the egregious and uniquely destructive behavior of the tobacco industry, lawmakers could, as an ethical matter of principle, refuse tobacco lobbyists' money and seek to remedy past harms.

Family and cultural influences on sleep development.

PubMed

Giannotti, Flavia; Cortesi, Flavia

2009-10-01

Sleep is a biopsychosocial process that is influenced by the complex interaction of biologic rhythms, including sleep homeostatic mechanisms, chronobiologic factors, parenting, and temperament. However, family structure, culturally specific values, and beliefs are all elements that impact the ecology of a child's sleep. Dramatic demographic changes in many countries have been witnessed in recent years, which have resulted in health professionals and pediatricians being confronted with families of widely differing cultural origins. Attitudes and beliefs on infant sleeping strongly influence whether or not infant sleep behavior is perceived as problematic. Thus, it is advantageous to explore a child's sleep behavior in a multicultural setting. Cultural comparisons are of intrinsic value because they allow not only a better understanding of sleep in different contexts but also an evaluation of the eventual benefits and consequences of different cultural sleep practices. This article provides an overview of some specific sleep-related behaviors and practices highly influenced by different cultural contexts.

Influence of bedding type on mucosal immune responses.

PubMed

Sanford, Amy N; Clark, Stephanie E; Talham, Gwen; Sidelsky, Michael G; Coffin, Susan E

2002-10-01

The mucosal immune system interacts with the external environment. In the study reported here, we found that bedding materials can influence the intestinal immune responses of mice. We observed that mice housed on wood, compared with cotton bedding, had increased numbers of Peyer's patches (PP) visible under a dissecting microscope. In addition, culture of lymphoid organs revealed increased production of total and virus-specific IgA by PP and mesenteric lymph node (MLN) lymphocytes from mice housed on wood, compared with cotton bedding. However, bedding type did not influence serum virus-specific antibody responses. These observations indicate that bedding type influences the intestinal immune system and suggest that this issue should be considered by mucosal immunologists and personnel at animal care facilities.

Influence versus intent for predictive analytics in situation awareness

NASA Astrophysics Data System (ADS)

Cui, Biru; Yang, Shanchieh J.; Kadar, Ivan

2013-05-01

Predictive analytics in situation awareness requires an element to comprehend and anticipate potential adversary activities that might occur in the future. Most work in high level fusion or predictive analytics utilizes machine learning, pattern mining, Bayesian inference, and decision tree techniques to predict future actions or states. The emergence of social computing in broader contexts has drawn interests in bringing the hypotheses and techniques from social theory to algorithmic and computational settings for predictive analytics. This paper aims at answering the question on how influence and attitude (some interpreted such as intent) of adversarial actors can be formulated and computed algorithmically, as a higher level fusion process to provide predictions of future actions. The challenges in this interdisciplinary endeavor include drawing existing understanding of influence and attitude in both social science and computing fields, as well as the mathematical and computational formulation for the specific context of situation to be analyzed. The study of `influence' has resurfaced in recent years due to the emergence of social networks in the virtualized cyber world. Theoretical analysis and techniques developed in this area are discussed in this paper in the context of predictive analysis. Meanwhile, the notion of intent, or `attitude' using social theory terminologies, is a relatively uncharted area in the computing field. Note that a key objective of predictive analytics is to identify impending/planned attacks so their `impact' and `threat' can be prevented. In this spirit, indirect and direct observables are drawn and derived to infer the influence network and attitude to predict future threats. This work proposes an integrated framework that jointly assesses adversarial actors' influence network and their attitudes as a function of past actions and action outcomes. A preliminary set of algorithms are developed and tested using the Global Terrorism

49 CFR 1103.16 - Adverse influences and conflicting interests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 8 2010-10-01 2010-10-01 false Adverse influences and conflicting interests. 1103.16 Section 1103.16 Transportation Other Regulations Relating to Transportation (Continued) SURFACE... Practitioner's Duties and Responsibilities Toward A Client § 1103.16 Adverse influences and conflicting...

The Influence of Group Dynamics on Collaborative Scientific Argumentation

ERIC Educational Resources Information Center

Ryu, Suna; Sandoval, William A.

2015-01-01

Research has addressed what instructional conditions may inhibit or promote scientific argumentation. Little research, however, has paid attention to interpersonal factors that influence collaborative argumentation. The present study examines the ways interpersonal factors affected group dynamics, which influence the features of collaborative…

How the demographic makeup of our community influences speech perception.

PubMed

Lev-Ari, Shiri; Peperkamp, Sharon

2016-06-01

Speech perception is known to be influenced by listeners' expectations of the speaker. This paper tests whether the demographic makeup of individuals' communities can influence their perception of foreign sounds by influencing their expectations of the language. Using online experiments with participants from all across the U.S. and matched census data on the proportion of Spanish and other foreign language speakers in participants' communities, this paper shows that the demographic makeup of individuals' communities influences their expectations of foreign languages to have an alveolar trill versus a tap (Experiment 1), as well as their consequent perception of these sounds (Experiment 2). Thus, the paper shows that while individuals' expectations of foreign language to have a trill occasionally lead them to misperceive a tap in a foreign language as a trill, a higher proportion of non-trill language speakers in one's community decreases this likelihood. These results show that individuals' environment can influence their perception by shaping their linguistic expectations.

Effect of social influence on effort-allocation for monetary rewards.

PubMed

Gilman, Jodi M; Treadway, Michael T; Curran, Max T; Calderon, Vanessa; Evins, A Eden

2015-01-01

Though decades of research have shown that people are highly influenced by peers, few studies have directly assessed how the value of social conformity is weighed against other types of costs and benefits. Using an effort-based decision-making paradigm with a novel social influence manipulation, we measured how social influence affected individuals' decisions to allocate effort for monetary rewards during trials with either high or low probability of receiving a reward. We found that information about the effort-allocation of peers modulated participant choices, specifically during conditions of low probability of obtaining a reward. This suggests that peer influence affects effort-based choices to obtain rewards especially under conditions of risk. This study provides evidence that people value social conformity in addition to other costs and benefits when allocating effort, and suggests that neuroeconomic studies that assess trade-offs between effort and reward should consider social environment as a factor that can influence decision-making.

COMPETITIVE ABILITY IN MALE HOUSE MICE (Mus musculus): GENETIC INFLUENCES

PubMed Central

Cunningham, Christopher B.; Ruff, James S.; Chase, Kevin; Potts, Wayne K.; Carrier, David R.

2013-01-01

Conspecifics of many animal species physically compete to gain reproductive resources and thus fitness. Despite the importance of competitive ability across the animal kingdom, specific traits that influence or underpin competitive ability are poorly characterized. Here, we investigate whether there are genetic influences on competitive ability within male house mice. Additionally, we examined if litter demographics (litter size and litter sex ratio) influence competitive ability. We phenotyped two generations for a male s ability to possess a reproductive resource--a prime nesting site--using semi-natural enclosures with mixed sex groupings. We used the animal model coupled with an extensive pedigree to estimate several genetic parameters. Competitive ability was found to be highly heritable, but only displayed a moderate genetic correlation to body mass. Interestingly, litter sex ratio had a weak negative influence on competitive ability. Litter size had no significant influence on competitive ability. Our study also highlights how much remians unknown about the proximal causes of competitive ability. PMID:23291957

Genetic influences on heart rate variability

PubMed Central

Golosheykin, Simon; Grant, Julia D.; Novak, Olga V.; Heath, Andrew C.; Anokhin, Andrey P.

2016-01-01

Heart rate variability (HRV) is the variation of cardiac inter-beat intervals over time resulting largely from the interplay between the sympathetic and parasympathetic branches of the autonomic nervous system. Individual differences in HRV are associated with emotion regulation, personality, psychopathology, cardiovascular health, and mortality. Previous studies have shown significant heritability of HRV measures. Here we extend genetic research on HRV by investigating sex differences in genetic underpinnings of HRV, the degree of genetic overlap among different measurement domains of HRV, and phenotypic and genetic relationships between HRV and the resting heart rate (HR). We performed electrocardiogram (ECG) recordings in a large population-representative sample of young adult twins (n = 1060 individuals) and computed HRV measures from three domains: time, frequency, and nonlinear dynamics. Genetic and environmental influences on HRV measures were estimated using linear structural equation modeling of twin data. The results showed that variability of HRV and HR measures can be accounted for by additive genetic and non-shared environmental influences (AE model), with no evidence for significant shared environmental effects. Heritability estimates ranged from 47 to 64%, with little difference across HRV measurement domains. Genetic influences did not differ between genders for most variables except the square root of the mean squared differences between successive R-R intervals (RMSSD, higher heritability in males) and the ratio of low to high frequency power (LF/HF, distinct genetic factors operating in males and females). The results indicate high phenotypic and especially genetic correlations between HRV measures from different domains, suggesting that >90% of genetic influences are shared across measures. Finally, about 40% of genetic variance in HRV was shared with HR. In conclusion, both HR and HRV measures are highly heritable traits in the general

The conflicting influences of religiosity on attitude toward torture.

PubMed

Malka, Ariel; Soto, Christopher J

2011-08-01

This research examines the thesis that religiosity has conflicting influences on Americans' attitudes about the use of torture on terrorism suspects: an organic influence favoring opposition to torture and a discursively driven influence favoring support of torture. In each of two national samples, religiosity had both a direct effect toward opposition to torture and an indirect effect-via conservative political alignment-toward support of torture. Multiple-group analyses revealed that the direct effect toward opposition to torture did not vary across Americans with differing levels of exposure to political discourse, whereas the indirect effect toward support of torture via conservative political alignment was much stronger among Americans highly exposed to political discourse. Among such individuals, the indirect effect was so strong that it completely counteracted the competing direct effect. Discussion focuses on the competing influences that a single nonpolitical psychological characteristic may have on a political preference.

Neural Correlates of Social Influence Among Cannabis Users.

PubMed

Gilman, Jodi M

2017-06-01

Although peer influence is an important factor in the initiation and maintenance of cannabis use, few studies have investigated the neural correlates of peer influence among cannabis users. The current review summarizes research on the neuroscience of social influence in cannabis users, with the goal of highlighting gaps in the literature and the need for future research. Brain regions underlying peer influence may function differently in cannabis users. Compared to non-using controls, regions of the brain underlying reward, such as the striatum, show greater connectivity with frontal regions, and also show hyperactivity when participants are presented with peer information. Other subcortical regions, such as the insula, show hypoactivation during social exclusion in cannabis users, indicating that neural responses to peer interactions may be altered in cannabis users. Although neuroscience is increasingly being used to study social behavior, few studies have specifically focused on cannabis use, and therefore it is difficult to draw conclusions about social mechanisms that may differentiate cannabis users and controls. This area of research may be a promising avenue in which to explore a critical factor underlying cannabis use and addiction.

The Facebook Influence Model: A Concept Mapping Approach

PubMed Central

Kota, Rajitha; Schoohs, Shari; Whitehill, Jennifer M.

2013-01-01

Abstract Facebook is a popular social media Web site that has been hypothesized to exert potential influence over users' attitudes, intentions, or behaviors. The purpose of this study was to develop a conceptual framework to explain influential aspects of Facebook. This mixed methods study applied concept mapping methodology, a validated five-step method to visually represent complex topics. The five steps comprise preparation, brainstorming, sort and rank, analysis, and interpretation. College student participants were identified using purposeful sampling. The 80 participants had a mean age of 20.5 years, and included 36% males. A total of 169 statements were generated during brainstorming, and sorted into between 6 and 22 groups. The final concept map included 13 clusters. Interpretation data led to grouping of clusters into four final domains, including connection, comparison, identification, and Facebook as an experience. The Facebook Influence Concept Map illustrates key constructs that contribute to influence, incorporating perspectives of older adolescent Facebook users. While Facebook provides a novel lens through which to consider behavioral influence, it can best be considered in the context of existing behavioral theory. The concept map may be used toward development of potential future intervention efforts. PMID:23621717

The Facebook influence model: a concept mapping approach.

PubMed

Moreno, Megan A; Kota, Rajitha; Schoohs, Shari; Whitehill, Jennifer M

2013-07-01

Facebook is a popular social media Web site that has been hypothesized to exert potential influence over users' attitudes, intentions, or behaviors. The purpose of this study was to develop a conceptual framework to explain influential aspects of Facebook. This mixed methods study applied concept mapping methodology, a validated five-step method to visually represent complex topics. The five steps comprise preparation, brainstorming, sort and rank, analysis, and interpretation. College student participants were identified using purposeful sampling. The 80 participants had a mean age of 20.5 years, and included 36% males. A total of 169 statements were generated during brainstorming, and sorted into between 6 and 22 groups. The final concept map included 13 clusters. Interpretation data led to grouping of clusters into four final domains, including connection, comparison, identification, and Facebook as an experience. The Facebook Influence Concept Map illustrates key constructs that contribute to influence, incorporating perspectives of older adolescent Facebook users. While Facebook provides a novel lens through which to consider behavioral influence, it can best be considered in the context of existing behavioral theory. The concept map may be used toward development of potential future intervention efforts.

Neural Correlates of Social Influence Among Cannabis Users

PubMed Central

Gilman, Jodi M.

2017-01-01

Purpose of review Although peer influence is an important factor in the initiation and maintenance of cannabis use, few studies have investigated the neural correlates of peer influence among cannabis users. The current review summarizes research on the neuroscience of social influence in cannabis users, with the goal of highlighting gaps in the literature and the need for future research. Recent findings Brain regions underlying peer influence may function differently in cannabis users. Compared to non-using controls, regions of the brain underlying reward, such as the striatum, show greater connectivity with frontal regions, and also show hyperactivity when participants are presented with peer information. Other subcortical regions, such as the insula, show hypoactivation during social exclusion in cannabis users, indicating that neural responses to peer interactions may be altered in cannabis users. Summary Although neuroscience is increasingly being used to study social behavior, few studies have specifically focused on cannabis use, and therefore it is difficult to draw conclusions about social mechanisms that may differentiate cannabis users and controls. This area of research may be a promising avenue in which to explore a critical factor underlying cannabis use and addiction. PMID:29057199

Redefining neuromarketing as an integrated science of influence.

PubMed

Breiter, Hans C; Block, Martin; Blood, Anne J; Calder, Bobby; Chamberlain, Laura; Lee, Nick; Livengood, Sherri; Mulhern, Frank J; Raman, Kalyan; Schultz, Don; Stern, Daniel B; Viswanathan, Vijay; Zhang, Fengqing Zoe

2014-01-01

Multiple transformative forces target marketing, many of which derive from new technologies that allow us to sample thinking in real time (i.e., brain imaging), or to look at large aggregations of decisions (i.e., big data). There has been an inclination to refer to the intersection of these technologies with the general topic of marketing as "neuromarketing". There has not been a serious effort to frame neuromarketing, which is the goal of this paper. Neuromarketing can be compared to neuroeconomics, wherein neuroeconomics is generally focused on how individuals make "choices", and represent distributions of choices. Neuromarketing, in contrast, focuses on how a distribution of choices can be shifted or "influenced", which can occur at multiple "scales" of behavior (e.g., individual, group, or market/society). Given influence can affect choice through many cognitive modalities, and not just that of valuation of choice options, a science of influence also implies a need to develop a model of cognitive function integrating attention, memory, and reward/aversion function. The paper concludes with a brief description of three domains of neuromarketing application for studying influence, and their caveats.

The Influence of Eccentricity Cycles on Exoplanet Habitability

NASA Astrophysics Data System (ADS)

Baskin, N. J. K.; Fabrycky, D. C.; Abbot, D. S.

2015-12-01

In our search for habitable exoplanets, it is important to understand how planetary habitability is influenced by orbital configurations that differ from those of the terrestrial planets in our Solar system. In particular, observational surveys have revealed the prevalence of planetary systems around binary stars. Within these systems, the gravitational influence of a companion star can induce libration in the eccentricity of the planet's orbit (referred to as Kozai Cycles) on timescales as short as thousands of years. The resulting fluctuations in stellar flux at the top of the atmosphere can potentially induce dramatic variations in surface temperatures, with direct implications for the planet's habitability prospects. We investigate this research problem using two steps. First, we utilize the MERCURY N-body integrator in order to calculate the eccentricity of a hypothetical Earth-analogue under the gravitational influence of a stellar companion. Second, we run a coupled Global Climate Model (GCM) at various stages of a cycle provided by the MERCURY runs in order to examine if the increase in insolation renders the planet uninhabitable. This work will allow us to better understand how Kozai cycles influence the boundaries of a planet's habitable zone.

Quantification of source region influences on the ozone burden

NASA Astrophysics Data System (ADS)

Treffeisen, Renate; Grunow, Katja; Möller, Detlev; Hainsch, Andreas

A project was performed to quantify different influences on the ozone burden. It could be shown that large-scale meteorological influences determine a very large percentage of the ozone concentration. Local measures intended to reduce peak ozone concentrations in summer turn out to be not very effective as a result. The aim of this paper is to quantify regional emission influences on the ozone burden. The investigation of these influences is possible by comparison of the ozone (O 3) and oxidant (O x=O 3+NO 2) concentrations at high-elevation sites downwind and upwind of a source region by using back trajectories. It has been shown that a separation between large-scale influenced meteorological and regional ozone burdens at these sites is possible. This method is applied for an important emission area in Germany—the Ruhrgebiet. On average, no significant ozone contribution of this area to the regional ozone concentration could be found. A large part of the ozone concentration is highly correlated with synoptic weather systems, which exhibit a dominant influence on the local ozone concentrations. Significant contributions of related photochemical ozone formation of the source area of 13-15% have been found only during favourable meteorological situations, identified by the hourly maximum day temperature being above 25°C. This is important with respect to the EU daughter directive to EU 96/62/EC (Official Journal L296 (1996) 55) because Member States should explore the possibilities of local measures to avoid the exceedance of threshold values and, if effective local measures exist, to implement them.

Parental Knowledge is an Environmental Influence on Adolescent Externalizing

PubMed Central

Marceau, Kristine; Narusyte, Jurgita; Lichtenstein, Paul; Ganiban, Jody M.; Spotts, Erica L.; Reiss, David; Neiderhiser, Jenae M.

2014-01-01

Background There is evidence both that parental monitoring is an environmental influence serving to diminish adolescent externalizing problems and that this association may be driven by adolescents’ characteristics via genetic and/or environmental mechanisms, such that adolescents with fewer problems tell their parents more, and therefore appear to be better monitored. Without information on how parents’ and children’s genes and environments influence correlated parent and child behaviors, it is impossible to clarify the mechanisms underlying this association. Method The present study used the Extended Children of Twins model to distinguish types of gene-environment correlation and direct environmental effects underlying associations between parental knowledge and adolescent (age 11-22 years) externalizing behavior with a Swedish sample of 909 twin parents and their adolescent offspring and a US-based sample of 405 White adolescent siblings and their parents. Results Results suggest that more parental knowledge is associated with less adolescent externalizing via a direct environmental influence independent of any genetic influences. There was no evidence of a child-driven explanation of the association between parental knowledge and adolescent externalizing problems. Conclusions In this sample of adolescents, parental knowledge exerted an environmental influence on adolescent externalizing after accounting for genetic influences of parents and adolescents. Because the association between parenting and child development originates in the parent, treatment for adolescent externalizing must not only include parents but should focus on altering their parental style. Thus, findings suggest that teaching parents better knowledge-related monitoring strategies is likely to help reduce externalizing problems in adolescents. PMID:24975929

Selective Influence through Conditional Independence.

ERIC Educational Resources Information Center

Dzhafarov, Ehtibar N.

2003-01-01

Presents a generalization and improvement for the definition proposed by E. Dzhafarov (2001) for selectiveness in the dependence of several random variables on several (sets of) external factors. This generalization links the notion of selective influence with that of conditional independence. (SLD)

Beyond Homophily: A Decade of Advances in Understanding Peer Influence Processes

ERIC Educational Resources Information Center

Brechwald, Whitney A.; Prinstein, Mitchell J.

2011-01-01

This article reviews empirical and theoretical contributions to a multidisciplinary understanding of peer influence processes in adolescence over the past decade. Five themes of peer influence research from this decade were identified, including a broadening of the range of behaviors for which peer influence occurs, distinguishing the sources of…

The Myth of Peer Influence in Adolescent Smoking Initiation

ERIC Educational Resources Information Center

Arnett, Jeffrey Jensen

2007-01-01

The widespread belief that peer influence is the primary cause of adolescent smoking initiation is examined and called into question. Correlational and longitudinal studies purporting to demonstrate peer influence are analyzed, and their limitations described. Qualitative interview studies of adolescent smoking initiation are presented as…

Influences on physicians' adoption of electronic detailing (e-detailing).

PubMed

Alkhateeb, Fadi M; Doucette, William R

2009-01-01

E-detailing means using digital technology: internet, video conferencing and interactive voice response. There are two types of e-detailing: interactive (virtual) and video. Currently, little is known about what factors influence physicians' adoption of e-detailing. The objectives of this study were to test a model of physicians' adoption of e-detailing and to describe physicians using e-detailing. A mail survey was sent to a random sample of 2000 physicians practicing in Iowa. Binomial logistic regression was used to test the model of influences on physician adoption of e-detailing. On the basis of Rogers' model of adoption, the independent variables included relative advantage, compatibility, complexity, peer influence, attitudes, years in practice, presence of restrictive access to traditional detailing, type of specialty, academic affiliation, type of practice setting and control variables. A total of 671 responses were received giving a response rate of 34.7%. A total of 141 physicians (21.0%) reported using of e-detailing. The overall adoption model for using either type of e-detailing was found to be significant. Relative advantage, peer influence, attitudes, type of specialty, presence of restrictive access and years of practice had significant influences on physician adoption of e-detailing. The model of adoption of innovation is useful to explain physicians' adoption of e-detailing.

Validation of the Cultural Influence on Helping Scale among Chinese Adolescents

ERIC Educational Resources Information Center

Law, Ben M. F.; Shek, Daniel T. L.

2011-01-01

The influence of culture on adolescent prosocial behavior is a neglected aspect in existing studies. Objectives: This study evaluates the psychometric properties of the Cultural Influence on Helping Scale (CIHS) among Chinese adolescents. CIHS is an instrument that assesses Chinese cultural influence on helping other people. Method: The CIHS was…

No Genetic Influence for Childhood Behavior Problems From DNA Analysis

PubMed Central

Trzaskowski, Maciej; Dale, Philip S.; Plomin, Robert

2013-01-01

Objective Twin studies of behavior problems in childhood point to substantial genetic influence. It is now possible to estimate genetic influence using DNA alone in samples of unrelated individuals, not relying on family-based designs such as twins. A linear mixed model, which incorporates DNA microarray data, has confirmed twin results by showing substantial genetic influence for diverse traits in adults. Here we present direct comparisons between twin and DNA heritability estimates for childhood behavior problems as rated by parents, teachers, and children themselves. Method Behavior problem data from 2,500 UK-representative 12-year-old twin pairs were used in twin analyses; DNA analyses were based on 1 member of the twin pair with genotype data for 1.7 million DNA markers. Diverse behavior problems were assessed, including autistic, depressive, and hyperactive symptoms. Genetic influence from DNA was estimated using genome-wide complex trait analysis (GCTA), and the twin estimates of heritability were based on standard twin model fitting. Results Behavior problems in childhood—whether rated by parents, teachers, or children themselves—show no significant genetic influence using GCTA, even though twin study estimates of heritability are substantial in the same sample, and even though both GCTA and twin study estimates of genetic influence are substantial for cognitive and anthropometric traits. Conclusions We suggest that this new type of “missing heritability,” that is, the gap between GCTA and twin study estimates for behavior problems in childhood, is due to nonadditive genetic influence, which will make it more difficult to identify genes responsible for heritability. PMID:24074471

Influence Diffusion Model in Text-Based Communication

NASA Astrophysics Data System (ADS)

Matsumura, Naohiro; Ohsawa, Yukio; Ishizuka, Mitsuru

Business people, especially marketing researchers, are keen to understand peoples' potential sense of value to create fascinating topics stimulating peoples' interest. In this paper, we aim at finding influential people, comments, and terms contributing the discovery of such topics. For this purpose, we propose an Influence Diffusion Model in text-based communication, where the influence of people, comments, and terms are defined as the degree of text-based relevance of messages. We apply this model to Bulletin Board Service(BBS) on the Internet, and present our discoveries on experimental evaluations.

Political and economic factors influencing contraceptive uptake.

PubMed

Sai, F T

1993-01-01

International, national and local level politics influence the uptake of contraception through consensuses, laws, financial and moral support or the creation of an enabling atmosphere. Opposition to contraception generally comes from some churches and groups opposed to particular technologies. Socio-economic factors, particularly education, the health care system and the perceived or actual cost of fertility regulation as compared to benefits expected from children also powerfully influence contraceptive use. For many poor women in developing countries their powerlessness in relation to their male partners is an important obstacle.

Machiavellian Beliefs and Social Influence.

ERIC Educational Resources Information Center

O'Hair, Dan; Cody, Michael J.

1987-01-01

Replicates previous findings of separate Machiavellian belief constructs (Deceit, Flatter, Immorality, and Cynicism). Indicates that different constructs predict selection of compliance-gaining strategies; for example, actors who scored high on Immorality used more referent influence on superiors. Discusses implications of this study concerning a…

Influence in Canonical Correlation Analysis.

ERIC Educational Resources Information Center

Romanazzi, Mario

1992-01-01

The perturbation theory of the generalized eigenproblem is used to derive influence functions of each squared canonical correlation coefficient and the corresponding canonical vector pair. Three sample versions of these functions are described, and some properties are noted. Two obvious applications, multiple correlation and correspondence…

Parenting Influences on the Social Goals of Aggressive Children

ERIC Educational Resources Information Center

McDonald, Kristina L.; Baden, Rachel E.; Lochman, John E.

2013-01-01

Although research has examined how parenting may influence children's social information processing, little research has examined how these factors may influence children's social goals. The current study examined how both parent- and child-reports of parenting behaviors were associated with regressed change in children's reported social goals…

Asking Better Questions: How Presentation Formats Influence Information Search

ERIC Educational Resources Information Center

Wu, Charley M.; Meder, Björn; Filimon, Flavia; Nelson, Jonathan D.

2017-01-01

While the influence of presentation formats have been widely studied in Bayesian reasoning tasks, we present the first systematic investigation of how presentation formats influence information search decisions. Four experiments were conducted across different probabilistic environments, where subjects (N = 2,858) chose between 2 possible search…

Key External Influences Affecting Consumers’ Decisions Regarding Food

PubMed Central

Martínez-Ruiz, María Pilar; Gómez-Cantó, Carmen María

2016-01-01

Among the numerous internal and external forces that compete for consumers’ attention in the context in which they buy their food, this paper will seek to provide a review of the most important external influences, such as the variables related to food itself. To this end, in addition to the food attributes traditionally identified in fields such as consumer behavior, it will give special consideration to the classification of food values. Although the influence of these variables on consumer decisions depends on the individual, analyzing them will undoubtedly increase understanding of consumers’ decisions. Additionally, identifying and describing these variables will enable subsequent research on how they influence both consumer behavior and other key outcomes for producers, manufacturers, and retailers in the food industry, such as satisfaction, trust, and loyalty. PMID:27803686

Awareness of social influence on food intake. An analysis of two experimental studies.

PubMed

Robinson, Eric; Field, Matt

2015-02-01

There is consistent evidence that the amount of food we consume can be influenced by the eating behaviour of other people. Some previous experimental studies reported that consumers are unaware of this influence on their behaviour. The present research tested whether people may be more aware of social influence on their eating than previously assumed. In two studies, participants (total n = 160) were exposed to information about the amount of snack food other people had been eating shortly before being served the same snack food and eating as much as they liked. After this, participants responded to questions regarding whether they thought their food intake had been socially influenced, and reported the reasons why they believed they had or had not been influenced. Of the 160 participants, 34% reported that they had been influenced, 10% were unsure and 56% reported they had not been influenced. Crucially, participants' reports of social influence appeared to be accurate; the food intake of participants reporting social influence was significantly affected by the amount of food other people had been eating, whereas the food intake of participants denying social influence was unaffected. Individuals may be more aware of the effect that social influence has on their eating behaviour than previously assumed. Further work is needed to identify the factors which determine whether people are susceptible to social influence on eating behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simulated thought insertion: Influencing the sense of agency using deception and magic.

PubMed

Olson, Jay A; Landry, Mathieu; Appourchaux, Krystèle; Raz, Amir

2016-07-01

In order to study the feeling of control over decisions, we told 60 participants that a neuroimaging machine could read and influence their thoughts. While inside a mock brain scanner, participants chose arbitrary numbers in two similar tasks. In the Mind-Reading Task, the scanner appeared to guess the participants' numbers; in the Mind-Influencing Task, it appeared to influence their choice of numbers. We predicted that participants would feel less voluntary control over their decisions when they believed that the scanner was influencing their choices. As predicted, participants felt less control and made slower decisions in the Mind-Influencing Task compared to the Mind-Reading Task. A second study replicated these findings. Participants' experience of the ostensible influence varied, with some reporting an unknown source directing them towards specific numbers. This simulated thought insertion paradigm can therefore influence feelings of voluntary control and may help model symptoms of mental disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

Influencing physician prescribing.

PubMed

Segal, R; Wang, F

1999-10-01

The drug use process suffers from problems related to quality and cost that have not responded well to administrative or educational interventions. In many cases, attempts to improve the quality of physician prescribing have been clumsy, often based on intuition. This article begins by describing the drug use process and the role of prescribing in that process. In the following section, we describe what is known about how physicians make drug choice decisions. The paper concludes with suggestions, based on evidence, about the design of strategies for influencing prescribing.

Media influences on children and adolescents: violence and sex.

PubMed

Earles, K A; Alexander, Randell; Johnson, Melba; Liverpool, Joan; McGhee, Melissa

2002-09-01

The portrayal of violence, sex, and drugs/alcohol in the media has been known to adversely affect the behavior of children and adolescents. There is a strong association between perceptions of media messages and observed behavior, especially with children. Lately, there has been more of a focus in the public health/medical field on media influences of youth and the role of the pediatrician and/or healthcare worker in addressing this area of growing concern. There is a need to explicitly explore the influences of media violence, sex, and drugs/alcohol on youth within the context of the Social Learning Theory. Implications of these influences are discussed, and recommendations for pediatricians and/or health care workers who interact with children and adolescents are described. Pediatricians and health care workers should incorporate media exposure probes into the developmental history of their patients and become knowledgeable about the effects of medial influences on youth.

The effects of peer influence on adolescent pedestrian road-crossing decisions.

PubMed

Pfeffer, K; Hunter, E

2013-01-01

Adolescence is a high-risk period for pedestrian injury. It is also a time of heightened susceptibility to peer influence. The aim of this research was to examine the effects of peer influence on the pedestrian road-crossing decisions of adolescents. Using 10 videos of road-crossing sites, 80 16- to 18-year-olds were asked to make pedestrian road-crossing decisions. Participants were assigned to one of 4 experimental conditions: negative peer (influencing unsafe decisions), positive peer (influencing cautious decisions), silent peer (who observed but did not comment), and no peer (the participant completed the task alone). Peers from the adolescent's own friendship group were recruited to influence either an unsafe or a cautious decision. Statistically significant differences were found between peer conditions. Participants least often identified safe road-crossing sites when accompanied by a negative peer and more frequently identified dangerous road-crossing sites when accompanied by a positive peer. Both cautious and unsafe comments from a peer influenced adolescent pedestrians' decisions. These findings showed that road-crossing decisions of adolescents were influenced by both unsafe and cautious comments from their peers. The discussion highlighted the role that peers can play in both increasing and reducing adolescent risk-taking.

Influences on children's dietary behavior, and innovative attempts to change it.

PubMed

Baranowski, Tom; Diep, Cassandra; Baranowski, Janice

2013-01-01

Fruit and vegetable (FV) intake may protect against several chronic diseases, and the preferences and habits in relation to FV intake appear to form in early childhood. Child FV intake reflects many influences from multiple levels (e.g. internal to the child, family, school, and neighborhood). We have documented influences at each of these levels, but more definitive research in longitudinal samples remains to be conducted. Even though validated comprehensive models of influences on child FV intake in longitudinal studies are not available to guide intervention design for children of different ages, there has been an urgency to initiate chronic disease prevention interventions to mitigate the substantial health consequences. Effective interventions use known behavior change procedures to change the influences on FV intake enough to change the behavior, but few such interventions have demonstrated effectiveness at meaningful levels. Innovative methods need to be explored. Videogames for Health offer a medium that is attractive to children and shows promising results, especially for dietary behavior change. Exciting additional research is needed to clarify possible bidirectional influences between the environmental and individual influences on child intake with possible age-related differences in influence and in the optimal design of video games for dietary change. Copyright © 2013 S. Karger AG, Basel.

Faculty and Peer Influences on Academic Integrity: College Cheating in Romania

ERIC Educational Resources Information Center

Teodorescu, Daniel; Andrei, Tudorel

2009-01-01

The purpose of this research was to examine student perceptions of academic integrity among faculty and peers at a sample of public universities in Romania. The study explores the factors that influence academic dishonesty among college students and compares the relative importance of faculty influences and peer influences on students' intent to…

Genetic and Environmental Influences on the Growth of Early Reading Skills

ERIC Educational Resources Information Center

Petrill, Stephen A.; Hart, Sara A.; Harlaar, Nicole; Logan, Jessica; Justice, Laura M.; Schatschneider, Christopher; Thompson, Lee; DeThorne, Laura S.; Deater-Deckard, Kirby; Cutting, Laurie

2010-01-01

Background: Studies have suggested genetic and environmental influences on overall level of early reading whereas the larger reading literature has shown environmental influences on the rate of growth of early reading skills. This study is the first to examine the genetic and environmental influences on both initial level of performance and rate…

Removal of clay by stingless bees: load size and moisture selection.

PubMed

Costa-Pereira, Raul

2014-09-01

Some organisms disperse energy, associated with the transportation of resource, which is not necessarily food. Stingless bees of Central Amazonia (Melipona flavolineata and M. lateralis) collect clay in banks along streams for nest building. The moisture of the clay varies along the bank, and bees collect clay from specific location, indicating that there is some sort of preference regarding their selection. This study aims at identifying: if larger bees carry more clay; if there is a preference for moisture of substrates; and if bees are less efficient accumulating and transporting clay when it is wet. In order to do so, I measured the size of the bees and of the pellets of clay found in the corbicula. I set up a field experiment to test substrate preferences. The amount of clay transported, increased exponentially in accordance to the size of the bee, and the preferred substrate was the driest clay. The amount and the efficiency of removal of clay were not affected by the moisture of the substrate. Despite the wet clay being denser, it does not reduce the efficiency of exploitation of the resource, but suggests that bees spend more energy to carry the same quantity of wet clay, which may be the underlying mechanism explaining their preference for removing drier clay.

Age and Family Control Influences on Children's Television Viewing.

ERIC Educational Resources Information Center

Rubin, Alan M.

1986-01-01

Indicates that (1) age and family control did not influence children's television viewing levels; (2) age influenced program preferences of children; (3) cartoon preferences related negatively to family control for the youngest groups; and (4) comedy and children's program preferences and television realism related positively to family control for…

Event-Based Plausibility Immediately Influences On-Line Language Comprehension

ERIC Educational Resources Information Center

Matsuki, Kazunaga; Chow, Tracy; Hare, Mary; Elman, Jeffrey L.; Scheepers, Christoph; McRae, Ken

2011-01-01

In some theories of sentence comprehension, linguistically relevant lexical knowledge, such as selectional restrictions, is privileged in terms of the time-course of its access and influence. We examined whether event knowledge computed by combining multiple concepts can rapidly influence language understanding even in the absence of selectional…

Potato stolon and tuber growth influenced by nitrogen form

USDA-ARS?s Scientific Manuscript database

Potato tuber initiation and its growth are key processes determining tuber yield, which are closely related to stolon growth, and are influenced by many factors including N nutrition. We investigated the influences of different forms of nitrogen (N) on stolon and tuber growth in sand culture with a ...

Recent Findings on Peer Group Influences on Adolescent Smoking

ERIC Educational Resources Information Center

Simons-Morton, Bruce G.; Farhat, Tilda

2010-01-01

This review addresses peer group influences on adolescent smoking with a particular focus on recently published longitudinal studies that have investigated the topic. Specifically, we examine the theoretical explanations for how social influence works with respect to adolescent smoking; discuss the association between peer and adolescent smoking;…

Personal Influence on the Decision to Join Voluntary Associations.

ERIC Educational Resources Information Center

Booth, Alan James

A longitudinal study (1961-1965) was planned to obtain information on the pervasiveness of personal influence with respect to decisions to join formal voluntary associations; examine the characteristics of opinion leaders and the individuals they influence; discover the differential patterns of joiners' exposure to mass communicated messages about…

Customer and mission influence on space station architecture

NASA Technical Reports Server (NTRS)

Runge, F. C.

1985-01-01

Overall Space Station architecture is presented in schematic outlines and plans. How the customer and mission needs influence this design is studied. The uses, occupants, activities, interfaces, utilities, locomotion, environments, and technological costs are all factors which influence the architecture. User and system functions are profiled, interfaces are characterized and functions are grouped. These lead to packaging of functions into modules and the design of system and user accommodations.

Even "unconscious thought" is influenced by attentional mechanisms.

PubMed

Srinivasan, Narayanan; Mukherjee, Sumitava

2014-02-01

In this commentary, we focus on the role of attentional mechanisms in unconscious thought. We argue that even distracted or unconscious thought is capacity limited and differences in scope of attention influence processing during unconscious thought. Attention also would influence processes at different stages in the proposed lens model. We conclude that there is a clear need to understand the role of attention to better understand conscious or unconscious thought.

Parental knowledge is an environmental influence on adolescent externalizing.

PubMed

Marceau, Kristine; Narusyte, Jurgita; Lichtenstein, Paul; Ganiban, Jody M; Spotts, Erica L; Reiss, David; Neiderhiser, Jenae M

2015-02-01

There is evidence both that parental monitoring is an environmental influence serving to diminish adolescent externalizing problems and that this association may be driven by adolescents' characteristics via genetic and/or environmental mechanisms, such that adolescents with fewer problems tell their parents more, and therefore appear to be better monitored. Without information on how parents' and children's genes and environments influence correlated parent and child behaviors, it is impossible to clarify the mechanisms underlying this association. The present study used the Extended Children of Twins model to distinguish types of gene-environment correlation and direct environmental effects underlying associations between parental knowledge and adolescent (age 11-22 years) externalizing behavior with a Swedish sample of 909 twin parents and their adolescent offspring and a US-based sample of 405 White adolescent siblings and their parents. Results suggest that more parental knowledge is associated with less adolescent externalizing via a direct environmental influence independent of any genetic influences. There was no evidence of a child-driven explanation of the association between parental knowledge and adolescent externalizing problems. In this sample of adolescents, parental knowledge exerted an environmental influence on adolescent externalizing after accounting for genetic influences of parents and adolescents. Because the association between parenting and child development originates in the parent, treatment for adolescent externalizing must not only include parents but should also focus on altering their parental style. Thus, findings suggest that teaching parents better knowledge-related monitoring strategies is likely to help reduce externalizing problems in adolescents. © 2014 The Authors. Journal of Child Psychology and Psychiatry. © 2014 Association for Child and Adolescent Mental Health.

Intelligence: Genetic and Environmental Influences.

ERIC Educational Resources Information Center

Cancro, Robert, Ed.

This book on the genetic and environmental influences on intelligence is comprised of the following papers: "The Structure of Intelligence in Relation to the Nature-Nurture Controversy," R. B. Cattell; "Theory of Intelligence," L. G. Humphreys; "Using Measured Intelligence Intelligently," P. R. Merrifield; "Intelligence: Definition, Theory, and…

The Influence of Marketing Education.

ERIC Educational Resources Information Center

Leventhal, Jerome I.

2002-01-01

A look at the history of marketing education shows how it has influenced the education of students and how its concepts are still being used in education today. Marketing educators were pioneers in educational opportunities for women, performance-based education, cooperative education, and leadership development. (JOW)

Physical Attractiveness and Interpersonal Influence

ERIC Educational Resources Information Center

Dion, Karen K.; Stein, Steven

1978-01-01

Examines the hypothesis that attractive individuals should be more successful with opposite-sex peers but less successful with same-sex peers than unattractive individuals. Also investigates the influence strategies employed by persons differing in attractiveness since nothing is currently known about the actual behavior exhibited by attractive…

Influences on Adolescents' Vocational Development.

ERIC Educational Resources Information Center

Mortimer, Jeylan T.; And Others

A study charted family, school, workplace, and community experiences that are relevant to the vocational development of high school students, focusing on five areas of influence: allowance practices within the family, economic status, paid work experience, volunteerism, and gender differences. The data were from the "Youth Development…

The influence of a temporary magnetic field on chicken hatching.

PubMed

Toman, Robert; Jedlicka, Jaroslav; Broucek, Ján

2002-01-01

The influence of magnetic field with the intensity of 0.07T on the hatching of the Hampshire breed chicken was investigated. The hatchability of the eggs that were influenced by magnetic field during the storage of the egg set (20-40 min) was increased in comparison with eggs that were not influenced by magnetic field (p < 0.05). In the eggs influenced by magnetic field during their incubation, the hatchability in experimental groups E1 and E2 decreased to 70.08 +/- 1.93% and 70.75 +/- 2.13%, respectively. The difference were significant (p < 0.001) in comparison with the control groups C1 and C2. The negative influence of magnetic field was manifested by lower weight of the hatched chickens in the experimental groups E1 (35.07 +/- 0.95 g) and E2 (35.94 +/- 0.97 g). The results were relevant (p < 0.05) in comparison with the control groups with the average weight of hatched chickens 41.83 +/- 1.15 g (C1) and 44.27 +/- 0.73 g (C2).

A reconsideration of parental and peer influences on adolescent deviance.

PubMed

Aseltine, R H

1995-06-01

The role of peers in fostering deviant behavior in adolescence is well-documented in the sociological literature, while support for parental influence or "control" theories of deviance is more equivocal. This paper examines the relative influences of parents and peers on adolescent delinquency and marijuana use, using data from a three-wave panel study of youths who were paired with a best friend (N = 435). Covariance structure models based upon polychoric correlations among study variables reveal that friends are indeed the primary source of influence on youths' behavior, but that estimates of influence are grossly overstated in analyses relying upon respondents' perceptions of their friends' behavior. Parental supervision and attachment are weakly related to subsequent delinquency and marijuana use, lending little support to control theories of deviance. Findings reveal that different processes account for the similarities among members of delinquent and drug-using peer groups. Although youths are socialized into delinquent behavior by peers, both selection and socialization influences play important roles in the formation of drug-using peer groups.

Synesthetic color experiences influence memory.

PubMed

Smilek, Daniel; Dixon, Mike J; Cudahy, Cera; Merikle, Philip M

2002-11-01

We describe the extraordinary memory of C, a 21-year-old student who experiences synesthetic colors (i.e., photisms) when she sees, hears, or thinks of digits. Using three matrices of 50 digits, we tested C and 7 nonsynesthetes to evaluate whether C's synesthetic photisms influence her memory for digits. One matrix consisted of black digits, whereas the other two matrices consisted of digits that were either incongruent or congruent with the colors of C's photisms. C's recall of the incongruently colored digits was considerably poorer than her recall of either the black or the congruently colored digits. The 7 nonsynesthetes did not show such differences in their recall of the matrices. In addition, when immediate recall of the black digits was compared with delayed recall of those digits (48 hr), C showed no decrease in performance, whereas each of the nonsynesthetes showed a significant decrease. These findings both demonstrate C's extraordinary memory and show that her synesthetic photisms can influence her memory for digits.

Factors influencing internal color of cooked meats.

PubMed

Suman, Surendranath P; Nair, Mahesh N; Joseph, Poulson; Hunt, Melvin C

2016-10-01

This manuscript overviews the pertinent research on internal color of uncured cooked meats, biochemical processes involved in meat cookery, and fundamental mechanisms governing myoglobin thermal stability. Heat-induced denaturation of myoglobin, responsible for the characteristic dull-brown color of cooked meats, is influenced by a multitude of endogenous (i.e., pH, muscle source, species, redox state) and exogenous (i.e., packaging, ingredients, storage) factors. The interactions between these factors critically influence the internal cooked color and can confuse the consumers, who often perceive cooked color to be a reliable indicator for doneness and safety. While certain phenomena in cooked meat color are cosmetic in nature, others can mislead consumers and result in foodborne illnesses. Research in meat color suggests that processing technologies and cooking practices in industry as well as households influence the internal cooked color. Additionally, the guidelines of many international public health and regulatory authorities recommend using meat thermometers to determine safe cooking endpoint temperature and to ensure product safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental influences predominate in remission from alcohol use disorder in young adult twins.

PubMed

McCutcheon, V V; Grant, J D; Heath, A C; Bucholz, K K; Sartor, C E; Nelson, E C; Madden, P A F; Martin, N G

2012-11-01

Familial influences on remission from alcohol use disorder (AUD) have been studied using family history of AUD rather than family history of remission. The current study used a remission phenotype in a twin sample to examine the relative contributions of genetic and environmental influences to remission. The sample comprised 6183 twins with an average age of 30 years from the Australian Twin Registry. Lifetime history of alcohol abuse and dependence symptoms and symptom recency were assessed with a structured telephone interview. AUD was defined broadly and narrowly as history of two or more or three or more abuse or dependence symptoms. Remission was defined as absence of symptoms at time of interview among individuals with lifetime AUD. Standard bivariate genetic analyses were conducted to derive estimates of genetic and environmental influences on AUD and remission. Environmental influences alone accounted for remission in males and for 89% of influences on remission in females, with 11% due to genetic influences shared with AUD, which decreased the likelihood of remission. For women, more than 80% of influences on remission were distinct from influences on AUD, and environmental influences were from individual experiences only. For men, just over 50% of influences on remission were distinct from those on AUD, and the influence of environments shared with the co-twin were substantial. The results for the broad and narrow phenotypes were similar. The current study establishes young adult remission as a phenotype distinct from AUD and highlights the importance of environmental influences on remission.

Modeling and numerical simulations of the influenced Sznajd model

NASA Astrophysics Data System (ADS)

Karan, Farshad Salimi Naneh; Srinivasan, Aravinda Ramakrishnan; Chakraborty, Subhadeep

2017-08-01

This paper investigates the effects of independent nonconformists or influencers on the behavioral dynamic of a population of agents interacting with each other based on the Sznajd model. The system is modeled on a complete graph using the master equation. The acquired equation has been numerically solved. Accuracy of the mathematical model and its corresponding assumptions have been validated by numerical simulations. Regions of initial magnetization have been found from where the system converges to one of two unique steady-state PDFs, depending on the distribution of influencers. The scaling property and entropy of the stationary system in presence of varying level of influence have been presented and discussed.

Modeling and numerical simulations of the influenced Sznajd model.

PubMed

Karan, Farshad Salimi Naneh; Srinivasan, Aravinda Ramakrishnan; Chakraborty, Subhadeep

2017-08-01

This paper investigates the effects of independent nonconformists or influencers on the behavioral dynamic of a population of agents interacting with each other based on the Sznajd model. The system is modeled on a complete graph using the master equation. The acquired equation has been numerically solved. Accuracy of the mathematical model and its corresponding assumptions have been validated by numerical simulations. Regions of initial magnetization have been found from where the system converges to one of two unique steady-state PDFs, depending on the distribution of influencers. The scaling property and entropy of the stationary system in presence of varying level of influence have been presented and discussed.

Influence Tactics in the Classroom and Their Relationship to Student Satisfaction