scholarly journals Environmental Stability and Long-term Variability of Harpacticoid Copepod Assemblages

Author(s):  
A I Azovsky ◽  
Elena S Chertoprud ◽  
Lesya Garlitska

Abstract Harpacticoid copepods of the Chernaya Bay (White Sea) intertidal zone were collected in 45 surveys carried out from spring to autumn over a 25-year period (1996-2020) at three sites that differed in sediment properties. There were no significant long-term trends or seasonal cycles in total abundance. Regarding the species composition, the differences between sites were the most important source of variability over the whole period while the fine-scale (within-habitat) variability was low. Epibenthic species prevailed in fine silty sand, both burrowing and epibenthic species prevailed in medium sand, and interstitial and burrowing species prevailed in coarse sand. A comparison of the data on harpacticoid assemblages from a number of geographically remote loci corroborated the generality of this pattern. In the temporal dimension, the structure of each community was stable until the early 2000s, when the proportion of epibenthic, burrowing and interstitial species changed following changes in sediment properties (increasing siltation at sandy sites and decreasing siltation at the silty site). At each site, there was an increasing long-term trend in diversity (both in total richness and in expected species number). This increase was particularly apparent at sandy sites because of the appearance of epibenthic species. We suggest that sediment composition is the key factor determining the composition of harpacticoid assemblages in space and time. The “ecomorphological profile”, i.e., the proportion of species with different lifestyle and morphological traits, is a useful and informative indicator for describing and typifying these assemblages.

Author(s):  
J. E. Laffoon ◽  
R. L. Anderson ◽  
J. C. Keller ◽  
C. D. Wu-Yuan

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).


Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.


RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 73575-73600 ◽  
Author(s):  
Eric Singh ◽  
Hari Singh Nalwa

The long-term environmental stability and degradation of graphene-based heterojunction solar cells under different atmospheric conditions such as air, humidity, temperature, and light illumination for commercial applications are discussed.


2021 ◽  
Author(s):  
Hao Xu ◽  
Xu Lian ◽  
Ingrid Slette ◽  
Hui Yang ◽  
Yuan Zhang ◽  
...  

Abstract The timing and length of the dry season is a key factor governing ecosystem productivity and the carbon cycle of the tropics. Mounting evidence has suggested a lengthening of the dry season with ongoing climate change. However, this conclusion is largely based on changes in precipitation (P) compared to its long-term average (P ̅) and lacks consideration of the simultaneous changes in ecosystem water demand (measured by potential evapotranspiration, Ep, or actual evapotranspiration, E). Using several long-term (1979-2018) observational datasets, we compared changes in tropical dry season length (DSL) and timing (dry season arrival, DSA, and dry season end, DSE) among three common metrics used to define the dry season: P < P ̅, P < Ep, and P < E. We found that all three definitions show that dry seasons have lengthened in much of the tropics since 1979. Among the three definitions, P < E estimates the largest fraction (49.0%) of tropical land area likely experiencing longer dry seasons, followed by P < Ep (41.4%) and P < P ̅ (34.4%). The largest differences in multi-year mean DSL (> 120 days) among the three definitions occurred in the most arid and the most humid regions of the tropics. All definitions and datasets consistently showed longer dry seasons in southern Amazon (due to delayed DSE) and central Africa (due to both earlier DSA and delayed DSE). However, definitions that account for changing water demand estimated longer DSL extension over those two regions. These results indicate that warming-enhanced evapotranspiration exacerbates dry season lengthening and ecosystem water deficit. Thus, it is necessity to account for the evolving water demand of tropical ecosystems when characterizing changes in seasonal dry periods and ecosystem water deficits in an increasingly warmer and drier climate.


2017 ◽  
Vol 26 (3) ◽  
pp. 219 ◽  
Author(s):  
Philip E. Camp ◽  
Meg A. Krawchuk

Human-caused wildfires are controlled by human and natural influences, and determining their key drivers is critical for understanding spatial patterns of wildfire and implementing effective fire management. We examined an array of explanatory variables that account for spatial controls of human-caused fire occurrence from 1990 to 2013 among six ecosystem zones that vary in human footprint and environmental characteristics in British Columbia, Canada. We found that long-term patterns of human-caused fire in ecosystem zones with a larger human footprint were strongly controlled by biophysical variables explaining conditions conducive to burning, whereas fire occurrence in remote ecosystem zones was controlled by various metrics of human activity. A metric representing the wildland–urban interface was a key factor explaining human-caused fire occurrence regardless of ecosystem zone. Our results contribute to the growing body of research on the varying constraints of spatial patterns of fire occurrence by explicitly examining human-caused fire and the heterogeneity of constraints based on human development.


1983 ◽  
Vol 46 (12) ◽  
pp. 356-359 ◽  
Author(s):  
Jenny Bodenham

This article deals with the resettlement of long-term mentally handicapped patients into independent living in wardened accommodation at Priory Court. The emphasis has been on ‘survival‘ and every person thought suitable for the project was given the opportunity to expand his concept of living and be discharged from a long-stay institutional environment. Motivation was the key factor, and staff and patients learnt much from the opportunity. The author gives an outline of the course taken and discusses some of the difficulties and triumphs. It was 3 years ago that long-stay institutional patients were discharged to the freedom of choosing a fuller way of life and from a distance the training team are able to see that these people are succeeding.


2009 ◽  
Vol 72 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Jemma Finch ◽  
Melanie J. Leng ◽  
Rob Marchant

AbstractLate Quaternary vegetation history and environmental changes in a biodiverse tropical ecosystem are inferred from pollen, charcoal and carbon isotope evidence derived from a ∼ 48,000-yr sedimentary record from the Uluguru Mountains, a component of the Eastern Arc Mountains of Kenya and Tanzania. Results indicate that Eastern Arc forest composition has remained relatively stable during the past ∼ 48,000 yr. Long-term environmental stability of the Eastern Arc forests has been proposed as a mechanism for the accumulation and persistence of species during glacial periods, thus resulting in the diverse forests observed today. The pollen and isotope data presented here indicate some marked changes in abundance but no significant loss in moist forest taxa through the last glacial maximum, thereby providing support for the long-term environmental stability of the Eastern Arc. Anthropogenic activities, including burning and forest clearance, were found to play a moderate role in shaping the mosaic of forest patches and high-altitude grasslands that characterise the site today; however, this influence was tempered by the inaccessibility of the mountain.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Zheheng Chen ◽  
Shanwen Zhang

The prestress level is a key factor of prestressed concrete (PSC) beams, affecting their long-term serviceability and safety. Existing monitoring methods, however, are not effective in obtaining the force or stress of embedded tendons. This paper investigates the feasibility of elastomagnetic (EM) sensors, which have been used for external tendons, in monitoring the long-term prestress loss of bonded tendons. The influence of ambient temperature, water, eccentricity ratio, plastic duct, and cement grouts on the test results of EM sensors is experimentally examined. Based on the calibrated EM sensors, prestress loss of a group of PSC beams was monitored for one year. In order to further consider the high randomness in material, environment, and construction, probabilistic analysis of prestress loss is conducted. Finally, the variation range of prestress loss with a certain confidence level is obtained and is compared with the monitored data, which provides a basis for the determination of prestress level in the design of PSC beams.


2021 ◽  
Vol 11 (11) ◽  
pp. 1155
Author(s):  
Fernanda Loureiro ◽  
Margarida Ferreira ◽  
Paula Sarreira-de-Oliveira ◽  
Vanessa Antunes

Schools are particularly suitable contexts for the implementation of interventions focused on adolescent sexual behavior. Sexual education and promotion have a multidisciplinary nature. Nurses’ role and the spectrum of the carried-out interventions is not clear. We aimed to identify interventions that promote a healthy sexuality among school adolescents. Our review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews and was registered in the Open Science Framework. Published articles on sexuality in adolescents in school contexts were considered. The research limitations included primary studies; access in full text in English, Spanish, or Portuguese; and no data publication limitation. Research was carried out on the EBSCOhost, PubMed, SciELO, and Web of Science platforms; gray literature and the bibliographies of selected articles were also searched. A total of 56 studies were included in the sample. The studies used a broad range of research methods, and 10 types of interventions were identified. Multi-interventional programs and socio-emotional interventions showed a greater impact on long-term behavioral changes, and continuity seemed to be a key factor. Long-term studies are needed to reach a consensus on the effectiveness of interventions. Nurses’ particular role on the multidisciplinary teams was found to be a gap in the research, and must be further explored.


2020 ◽  
Author(s):  
Yassar Alamri ◽  
Erik Monasterio ◽  
Lutz Beckert ◽  
Tim J Wilkinson

Abstract BackgroundA student’s motivation is a key factor in their success in undertaking an education endeavour. However, how this relates to involvement in research by medical students is unclear.MethodsAn electronic questionnaire was sent to all medical students at our institution. To ascertain students’ motivation to undertake research, they were asked an open-ended question to describe the single major factor that would encourage them to get involved in research as a medical student. A framework of self-determination theory was used to deductively code the responses as intrinsic motivation (‘IM’; e.g., interest/passion) or extrinsic motivation (‘EM’; e.g. improving CV). The two groups were then contrasted in relation to their research engagement.ResultsA total of 348 students were included in the survey, of whom 204 were coded as IM responses, and 144 were coded as EM responses. Students who engaged in extra-curricular research activities were more likely to report an underlying EM (48% vs. 36%, p = 0.03). They were also older (23.7 ± 3.5 vs. 21.9 ± 3.7, p = 0.005), and more likely to have completed a prior research degree (15% vs. 3%, p = 0.01).ConclusionIn this study, EM was a bigger influencer on research involvement by medical students than IM. Future studies should explore promoters of IM, and include longitudinal data in order to assess whether EM students continue to be involved in research long-term.


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