scholarly journals Long-term change in the parasite burden of shore crabs ( Hemigrapsus oregonensis and Hemigrapsus nudus ) on the northwestern Pacific coast of North America

2021 ◽  
Vol 288 (1945) ◽  
pp. 20203036
Author(s):  
Jessica Quinn ◽  
Sarah Lee ◽  
Duncan Greeley ◽  
Alyssa Gehman ◽  
Armand M. Kuris ◽  
...  
Keyword(s):  
Parasite Burden ◽  
Shore Crab ◽  
Northwestern Pacific ◽  
Intermediate Hosts ◽  
Term Change ◽  
Shore Crabs ◽  
Living Species ◽  
Hemigrapsus Oregonensis ◽  
Over Time

The abundances of free-living species have changed dramatically in recent decades, but little is known about change in the abundance of parasitic species. We investigated whether populations of several parasites have shifted over time in two shore crab hosts, Hemigrapsus oregonensis and Hemigrapsus nudus, by comparing the prevalence and abundance of three parasite taxa in a historical dataset (1969–1970) to contemporary parasite abundance (2018–2020) for hosts collected from 11 intertidal sites located from Oregon, USA, to British Columbia, Canada. Our data suggest that the abundance of the parasitic isopod Portunion conformis has varied around a stable mean for the past 50 years. No change over time was observed for larval acanthocephalans. However, larval microphallid trematodes increased in prevalence over time among H. oregonensis hosts, from a mean of 8.4–61.8% between the historical and contemporary time points. The substantial increase in the prevalence of larval microphallid trematodes could be owing to increased abundances of their bird final hosts, increased production of parasite infective stages by snail intermediate hosts or both. Our study highlights the variability among parasite species in their temporal trajectories of change.

Genetics of Circulating HbA1c Long-Term Change over Time in Nondiabetic Subjects—The Long Life Family Study

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 1709-P
Author(s):  
PING AN ◽  
PETRA LENZINI ◽  
BHARAT THYAGARAJAN ◽  
JOSEPH H. LEE ◽  
JOSEPH M. ZMUDA ◽  
...  
Keyword(s):  
Family Study ◽  
Change Over Time ◽  
Term Change ◽  
Long Life ◽  
Over Time

scholarly journals Reducing Implicit Racial Preferences: II. Intervention Effectiveness Across Time

2016 ◽  
Author(s):  
Calvin K. Lai ◽  
Brian A. Nosek ◽  
Giuseppe Sartori ◽  
Jiyun Elizabeth L. Shin ◽  
Maddalena Marini ◽  
...  
Keyword(s):  
Intervention Effectiveness ◽  
Short Term ◽  
Racial Preferences ◽  
Term Change ◽  
Implicit Preferences ◽  
Over Time

Implicit preferences are malleable, but does that change last? We tested 9 interventions (8 real and 1 sham) to reduce implicit racial preferences over time. In 2 studies with a total of 6,321 participants, all 9 interventions immediately reduced implicit preferences. However, none were effective after a delay of several hours to several days. We also found that these interventions did not change explicit racial preferences and were not reliably moderated by motivations to respond without prejudice. Short-term malleability in implicit preferences does not necessarily lead to long-term change, raising new questions about the flexibility and stability of implicit preferences.

Spatiotemporal heterogeneity in recruitment of larval parasites to shore crab intermediate hosts: the influence of shorebird definitive hosts

2003 ◽  
Vol 81 (7) ◽  
pp. 1282-1291 ◽  
Author(s):  
A David M. Latham ◽  
Robert Poulin
Keyword(s):  
Spatial Heterogeneity ◽  
Abiotic Factors ◽  
Spatial Dynamics ◽  
Shore Crab ◽  
Intermediate Hosts ◽  
Weak Evidence ◽  
Shore Crabs ◽  
Temporal And Spatial ◽  
Animal Communities ◽  
Larval Parasites

Parasitism is a major biotic determinant of animal population dynamics and community structure. Temporal and spatial heterogeneity in parasitism is commonly observed in intermediate host populations. Understanding the causes of temporal and spatial variation in the recruitment of parasites is crucial if we are to manage host populations and animal communities effectively. Here, the temporal and spatial dynamics of Profilicollis antarcticus and Profilicollis novaezelandensis (Acanthocephala) infections in three species of shore crabs (Macrophthalmus hirtipes, Hemigrapsus edwardsii, and Hemigrapsus crenulatus) are examined in relation to the distribution and abundance of shorebird definitive hosts. Temporal patterns of infection were observed in M. hirtipes but not the other two species. Spatial heterogeneity in recruitment of acanthocephalan larvae to M. hirtipes and H. edwardsii populations was found both within and between locations. Weak evidence is found that infection levels in crab populations are related to the distribution and abundance of shorebird hosts both temporally and spatially. In this system, abiotic factors seem to be at least as important in determining how infection levels vary in time and space as the input of parasite eggs from bird definitive hosts.

Post-larval mortality of the endoparasitic isopod castrator Portunion conformis (Epicaridea: Entoniscidae) in the shore crab, Hemigrapsus oregonensis, with a description of the host response

Parasitology ◽  
1980 ◽  
Vol 80 (2) ◽  
pp. 211-232 ◽  
Author(s):  
Armand M. Kuris ◽  
George O. Poinar ◽  
Roberta T. Hess
Keyword(s):  
Host Response ◽  
Larval Mortality ◽  
Parasite Population ◽  
Shore Crab ◽  
Differential Mortality ◽  
Multiple Infection ◽  
High Prevalence ◽  
Shore Crabs ◽  
Parasitic Castrator ◽  
Hemigrapsus Oregonensis

SummaryThe shore crabs, Hemigrapsus oregonensis and H. nudus, sometimes kill the female endoparasitic entoniscid isopod, Portunion conformis, a parasitic castrator. Studies of host populations from Baja California, Mexico to Vancouver Island, Canada, show that the incidence of parasitized hosts with dead parasites and the percentage of the parasite population found dead vary markedly with locality but only occasionally with season. Both higher incidences of hosts with dead P. conformis and higher proportions of the total parasite population found dead are associated with (1) high prevalence of parasitism, (2) female hosts and (3) large hosts. Within a host, the proportion of the parasites that are dead is not related to the degree of multiple infection. Typically, either all or none of the parasites in a multiple infection are dead. Supernumerary juvenile parasites do not suffer differential mortality. The developmental stage of the female parasite does not seem to influence the likelihood of death. The presence of dead parasites may not confer an acquired immunity to re-infection. These features suggest that parasite death is typically the result of activation of a successful host defensive process rather than indicative of a defect on the part of the parasites. Parasitized female hosts can regain their reproductive capabilities following death of the parasite. Post-parasitic broods are smaller than normal. Reproductive recovery is presumed to provide the selective pressure favouring evolution of a lethal host response. The host-produced sheath surrounding female parasites is a haemocytic response. Sheaths enclosing dead parasites are thicker and more electron dense than those containing healthy parasites. The sheath of a healthy P. conformis may actually protect the parasite from a more intense host response.

Professionalization of Legislatures: Long-Term Change in Political Recruitment in Denmark and Norway

1978 ◽  
Vol 20 (2) ◽  
pp. 286-318 ◽  
Author(s):  
Kjell A. Eliassen ◽  
Mogens N. Pedersen
Keyword(s):  
Term Change ◽  
Political Recruitment ◽  
Socioeconomic Composition ◽  
Over Time

Everywhere a disparity can be observed between the socioeconomic composition of the electorate and the composition of the elected, representative body, which acts as a legislature for the society. Microcosm and macro- cosm are never identical; the legislature never mirrors the population at large. This is a universal generalization. It holds true for all representative systems at all times. It is furthermore true that the character of this disparity differs cross-nationally and over time: each legislature is unique in this sense.

Vivid Imagers Are Better at Detecting Salient Changes

2006 ◽  
Vol 27 (4) ◽  
pp. 218-228 ◽  
Author(s):  
Paul Rodway ◽  
Karen Gillies ◽  
Astrid Schepman
Keyword(s):  
Individual Differences ◽  
Change Detection ◽  
Visual Imagery ◽  
Detection Task ◽  
Level Of Detail ◽  
Detection Accuracy ◽  
Change Detection Task ◽  
Term Change ◽  
High Level

This study examined whether individual differences in the vividness of visual imagery influenced performance on a novel long-term change detection task. Participants were presented with a sequence of pictures, with each picture and its title displayed for 17  s, and then presented with changed or unchanged versions of those pictures and asked to detect whether the picture had been changed. Cuing the retrieval of the picture's image, by presenting the picture's title before the arrival of the changed picture, facilitated change detection accuracy. This suggests that the retrieval of the picture's representation immunizes it against overwriting by the arrival of the changed picture. The high and low vividness participants did not differ in overall levels of change detection accuracy. However, in replication of Gur and Hilgard (1975) , high vividness participants were significantly more accurate at detecting salient changes to pictures compared to low vividness participants. The results suggest that vivid images are not characterised by a high level of detail and that vivid imagery enhances memory for the salient aspects of a scene but not all of the details of a scene. Possible causes of this difference, and how they may lead to an understanding of individual differences in change detection, are considered.

Enhancing community welfare through improved water quality: a case for applying staggered pollution charges in the river Musi sub-basin of Andhra Pradesh, India

Water Policy ◽  
2005 ◽  
Vol 7 (5) ◽  
pp. 469-483
Author(s):  
Tishya Chatterjee
Keyword(s):  
Andhra Pradesh ◽  
Relevant Literature ◽  
Pollution Prevention ◽  
Economic Benefits ◽  
Environmental Damage ◽  
Marginal Costs ◽  
Community Acceptance ◽  
Level Data ◽  
Over Time

In conditions of severe water-pollution and dormant community acceptance of accumulating environmental damage, the regulator's role goes beyond pollution prevention and more towards remediation and solutions based on the community's long-term expectations of economic benefits from clean water. This paper suggests a method to enable these benefits to become perceptible progressively, through participatory clean-up operations, supported by staggered pollution charges. It analyses the relevant literature on pollution prevention and applies a cost-based “willingness to pay” model, using primary basin-level data of total marginal costs. It develops a replicable demand-side approach imposing charge-standard targets over time in urban-industrial basins of developing countries.

The Short-Term and Long-Term Impacts of Sarbanes-Oxley Act on Composition and Characteristics of Corporate Board of Directors

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Halil Kaya ◽  
Gaurango Banerjee
Keyword(s):  
Board Composition ◽  
Corporate Boards ◽  
Corporate Accountability ◽  
Corporate Board ◽  
Short Term ◽  
Dual Roles ◽  
Board Characteristics ◽  
Sarbanes Oxley ◽  
Over Time

The paper examines the Sarbanes-Oxley (2002) Acts immediate impact on board composition and characteristics as well as possible reversals in its impact over time. Effects on directors age and tenure are analyzed over the 2001-06 sample period. Female participation in corporate boards is also studied in the pre-SOX and post-SOX periods. The dual roles of directors in being a member of the board as well as serving as either CEO, CFO, Chairman, Co-Chair, Founder, or Lead Director of their respective companies is also examined. We observe a short-term impact of SOX on board compositions due to changes seen in board characteristics between 2001 (pre-SOX), and 2003-05 short-term period (post-SOX). Also, we observe a reversal of board characteristics in 2006 to pre-SOX levels implying that the effects of SOX on board composition were short-lived, and needs to be monitored over time to ensure adherence to corporate accountability guidelines over the long-term.

Social Cohesion, Breaks, and Transformations in Italy, 535–600

2018 ◽  
Author(s):  
Walter Pohl
Keyword(s):  
The Political ◽  
Late Antique ◽  
Religious Context ◽  
Ancient Society ◽  
Complex Process ◽  
Term Change ◽  
Two Generations ◽  
Classical Culture

When the Gothic War began in Italy in 535, the country still conserved many features of classical culture and late antique administration. Much of that was lost in the political upheavals of the following decades. Building on Chris Wickham’s work, this contribution sketches an integrated perspective of these changes, attempting to relate the contingency of events to the logic of long-term change, discussing political options in relation to military and economic means, and asking in what ways the erosion of consensus may be understood in a cultural and religious context. What was the role of military entrepreneurs of more or less barbarian or Roman extraction in the distribution or destruction of resources? How did Christianity contribute to the transformation of ancient society? The old model of barbarian invasions can contribute little to understanding this complex process. It is remarkable that for two generations, all political strategies in Italy ultimately failed.

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