Origin and Diversity of Marine Larvae

2018 ◽  
Keyword(s):  
Life Cycle ◽  
Filter Feeding ◽  
Ecological Variation ◽  
Different Types ◽  
Marine Larvae ◽  
Planktotrophic Larvae ◽  
Plausible Theory

The origin of larvae has been much discussed, but the most plausible theory is the “terminal addition theory,” which proposes that the larvae originated when a benthic stage was added to the ancestral holoplanktonic life cycle, with the planktonic stage retained as the larva. Marine larvae show an astonishing morphological and ecological variation. Planktotrophic larvae are found in many smaller or larger lineages, and characteristic types—such as the trochophore of many annelids and molluscs, the cyphonautes of some bryozoans, the actinotrocha of most phoronids, the pluteus larvae of most echinoderms, and the tornaria of some enteropneusts—are familiar members of the plankton. These larvae show different types of ciliary filter feeding: trochophores have downstream-collecting, cyphonautes and actinotrocha have ciliary-sieving, and pluteus and actiunotrocha have upstream-collecting feeding. Crustacean larvae show a variety of feeding mechanisms. Lecithotrophic larvae are found in all phyla. A panorama of marine larvae is presented.

Antecedents of parental psychological control: A narrative review grounded in Self-Determination Theory perspective

2020 ◽  
pp. 29-54
Author(s):  
Sebastiano Costa ◽  
Francesca Liga ◽  
Maria Cristina Gugliandolo ◽  
Simona Sireno ◽  
Rosalba Larcan ◽  
...  
Keyword(s):  
Life Cycle ◽  
Social Environment ◽  
Psychological Control ◽  
Self Determination Theory ◽  
Theoretical Framework ◽  
Self Determination ◽  
Parental Psychological Control ◽  
Parental Characteristics ◽  
Different Types ◽  
Control Construct

Self-determination theory has become a consolidated theoretical framework to deepen the psychological control construct. Numerous studies have widely investigated the consequences of the use of this parenting strategy during the life cycle. Although studies focused on the antecedents of parental psychological control are not so numerous, they provide an interesting picture that needs to be systematized and organized. For this reason, this narra-tive review was aimed at describing the studies on the antecedents of psychological control that used SDT as a theoretical framework. These studies were structured according to three categories: Parental Characteristics (or pressure from within), Child Characteristics (pres-sure from below), and Family Social Environment Characteristics (pressure from above). The results highlighted a wealth of studies in each category and indicating the need to con-tinue this line of studies in the future through the integration of the different types of ante-cedents too.

scholarly journals Potential Effects of Human Papillomavirus Type Substitution, Superinfection Exclusion and Latency on the Efficacy of the Current L1 Prophylactic Vaccines

Viruses ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
Ian N. Hampson ◽  
Anthony W. Oliver ◽  
Lynne Hampson
Keyword(s):  
Life Cycle ◽  
High Risk ◽  
Outcome Data ◽  
Benign Lesions ◽  
Complex Dynamic ◽  
Papilloma Virus ◽  
Superinfection Exclusion ◽  
Different Types ◽  
Hpv Types ◽  
Type Substitution

There are >200 different types of human papilloma virus (HPV) of which >51 infect genital epithelium, with ~14 of these classed as high-risk being more commonly associated with cervical cancer. During development of the disease, high-risk types have an increased tendency to develop a truncated non-replicative life cycle, whereas low-risk, non-cancer-associated HPV types are either asymptomatic or cause benign lesions completing their full replicative life cycle. HPVs can also be present as non-replicative so-called “latent” infections and they can also show superinfection exclusion, where cells with pre-existing infections with one type cannot be infected with a different HPV type. Thus, the HPV repertoire and replication status present in an individual can form a complex dynamic meta-community which changes with respect to both time and exposure to different HPV types. In light of these considerations, it is not clear how current prophylactic HPV vaccines will affect this system and the potential for iatrogenic outcomes is discussed in light of recent outcome data.

scholarly journals Project Narratives That Potentially Perform and Change the Future

2021 ◽  
pp. 875697282199534
Author(s):  
Natalya Sergeeva ◽  
Graham M. Winch
Keyword(s):  
Life Cycle ◽  
Value Creation ◽  
Future Research ◽  
Future Research Agenda ◽  
Project Life Cycle ◽  
Different Types ◽  
The Future ◽  
Organizational Narrative ◽  
Project Life ◽  
Future Project

This article develops a framework for applying organizational narrative theory to understand project narratives that potentially perform and change the future. Project narratives are temporal but often get repeated throughout the project life cycle to stabilize meaning, and could be about project mission, vision, identity, value creation, and so forth. Project narratives have important implications for organizational identity and image crafting. This article differentiates among different types of project narratives in relation to a project life cycle, providing case studies of project narratives on three major UK rail projects. We then set out the future research agenda into project narrative work.

scholarly journals Engineering Design Process of Face Masks Based on Circularity and Life Cycle Assessment in the Constraint of the COVID-19 Pandemic

2021 ◽  
Vol 13 (9) ◽  
pp. 4948
Author(s):  
Núria Boix Rodríguez ◽  
Giovanni Formentini ◽  
Claudio Favi ◽  
Marco Marconi
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Sustainability ◽  
Design Guidelines ◽  
New Device ◽  
Engineering Design Process ◽  
Life Cycle Perspective ◽  
Different Types ◽  
3D Printed ◽  
Negative Impacts

Face masks are currently considered key equipment to protect people against the COVID-19 pandemic. The demand for such devices is considerable, as is the amount of plastic waste generated after their use (approximately 1.6 million tons/day since the outbreak). Even if the sanitary emergency must have the maximum priority, environmental concerns require investigation to find possible mitigation solutions. The aim of this work is to develop an eco-design actions guide that supports the design of dedicated masks, in a manner to reduce the negative impacts of these devices on the environment during the pandemic period. Toward this aim, an environmental assessment based on life cycle assessment and circularity assessment (material circularity indicator) of different types of masks have been carried out on (i) a 3D-printed mask with changeable filters, (ii) a surgical mask, (iii) an FFP2 mask with valve, (iv) an FFP2 mask without valve, and (v) a washable mask. Results highlight how reusable masks (i.e., 3D-printed masks and washable masks) are the most sustainable from a life cycle perspective, drastically reducing the environmental impacts in all categories. The outcomes of the analysis provide a framework to derive a set of eco-design guidelines which have been used to design a new device that couples protection requirements against the virus and environmental sustainability.

Life Cycle Assessment of Photovoltaics; Update of the ecoinvent Database

2007 ◽  
Vol 1041 ◽  
Author(s):  
Niels Jungbluth ◽  
Roberto Dones ◽  
Rolf Frischknecht
Keyword(s):  
Life Cycle ◽  
Environmental Impacts ◽  
Electricity Production ◽  
Research Projects ◽  
Industry Association ◽  
Ecoinvent Database ◽  
Federal Authority ◽  
Different Types ◽  
Production Stages ◽  
Background Database

AbstractRecently, the data for photovoltaics in the ecoinvent database have been updated on behalf of the European Photovoltaics Industry Association and the Swiss Federal Authority for Energy. Data have been collected in this project directly from manufacturers and were provided by other research projects. LCA studies from different authors are considered for the assessment. The information is used to elaborate a life cycle inventory from cradle to grave for the PV electricity production in 3kWp plants in the year 2005.The inventories cover mono- and polycrystalline cells, amorphous and ribbon-silicon, CdTe and CIS thin film cells. Environmental impacts due to the infrastructure for all production stages and the effluents from wafer production are also considered. The ecoinvent database is used as background database.Results from the LCA study are presented, comparing different types of cells and analysing also the electricity production in a range of different countries. It is also discussed how the environmental impacts of photovoltaics have been reduced over the last 15 years, using the CED indicator. The consistent and coherent LCI datasets for basic processes make it easier to perform LCA studies, and increase the credibility and acceptance of the life cycle results. The content of the PV LCI datasets is made publicly available via the website www.ecoinvent.org for ecoinvent members.

Analysis of the juvenile shell of Lingula anatina (Brachiopoda: Linguliformea) provides insight into the evolution of life cycles of fossil brachiopods

Paleobiology ◽  
2020 ◽  
pp. 1-15
Author(s):  
Anna A. Madison ◽  
Tatyana V. Kuzmina ◽  
Elena N. Temereva
Keyword(s):  
Life Cycle ◽  
Anterior Margin ◽  
The Philippines ◽  
Life Cycles ◽  
Published Data ◽  
Egg Envelope ◽  
Evolution Of Life ◽  
The Republic ◽  
Planktotrophic Larvae ◽  
Insight Into

Abstract Inferences on the development and morphology of extinct brachiopods must be informed by the ontogeny and shell ornamentation of extant brachiopods. Although the adult shells of extant brachiopods are well studied, detailed descriptions of the embryonic and juvenile shells of extant lingulides are lacking. Here, we describe in detail the shells of juveniles of Lingula anatina Lamarck, 1801 from Vietnam and the Republic of the Philippines. The following previously unknown properties of the lingulide shell are described: (1) a distinct border between the protegulum and the brephic shell; (2) drapes that develop on both the protegulum and brephic shell; and (3) the notched anterior margin of the brephic shell. The drapes and cogs on the brephic shell may be caused by the formation of setal follicles during the planktonic stage. Specimens of L. anatina from the Philippines have larger brephic shells than those from Vietnam, probably because the former have a longer planktonic stage. Based on comparisons of the first-formed shells of extant brachiopods with published data on fossil brachiopods, we suggest that the life cycle of extant lingulides, in which planktotrophic juveniles with a shell hatch from the egg envelope, is the most evolutionarily advanced brachiopod life cycle and appeared in the early Silurian. We suggest criteria for determining the type of life cycle based on the structure of the first-formed shell of brachiopods. Finally, we consider hypothetical scenarios of life cycles of fossil brachiopods, including true planktotrophic larvae in the Cambrian linguliforms.

Hong Kong Metro's Traction Equipment: The Drive for Efficiency

1992 ◽  
Vol 206 (1) ◽  
pp. 67-74
Author(s):  
A D Moyes
Keyword(s):  
Energy Efficiency ◽  
Hong Kong ◽  
Life Cycle ◽  
Energy Saving ◽  
Mass Transit ◽  
Life Cycle Costs ◽  
Design Features ◽  
Different Types ◽  
Multiple Unit ◽  
Traction Equipment

This paper describes the evolution of the electric multiple unit traction equipment of the Hong Kong Mass Transit Railway Corporation (MTRC). Traction energy efficiency is particularly important to the MTRC and has been improved by 46 per cent on the most recently supplied cars. The justification for the conversion of the existing camshaft cars to chopper control and the relative merits of different types of drives in MTRC's application are discussed. The utilization of energy, the method used to optimize coasting for energy saving, life-cycle costs and the design features of the gate turn-off thyristor chopper cars are described.

scholarly journals Differential role of nonmuscle myosin II isoforms during blebbing of MCF-7 cells

2017 ◽  
Vol 28 (8) ◽  
pp. 1034-1042 ◽  
Author(s):  
Sumit K. Dey ◽  
Raman K. Singh ◽  
Shyamtanu Chattoraj ◽  
Shekhar Saha ◽  
Alakesh Das ◽  
...  
Keyword(s):  
Life Cycle ◽  
Actin Filament ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
Different Types ◽  
Membrane Protrusions ◽  
Bleb Formation ◽  
Mcf 7

Bleb formation has been correlated with nonmuscle myosin II (NM-II) activity. Whether three isoforms of NM-II (NM-IIA, -IIB and -IIC) have the same or differential roles in bleb formation is not well understood. Here we report that ectopically expressed, GFP-tagged NM-II isoforms exhibit different types of membrane protrusions, such as multiple blebs, lamellipodia, combinations of both, or absence of any such protrusions in MCF-7 cells. Quantification suggests that 50% of NM-IIA-GFP–, 29% of NM-IIB-GFP–, and 19% of NM-IIC1-GFP–expressing MCF-7 cells show multiple bleb formation, compared with 36% of cells expressing GFP alone. Of interest, NM-IIB has an almost 50% lower rate of dissociation from actin filament than NM-IIA and –IIC1 as determined by FRET analysis both at cell and bleb cortices. We induced bleb formation by disruption of the cortex and found that all three NM-II-GFP isoforms can reappear and form filaments but to different degrees in the growing bleb. NM-IIB-GFP can form filaments in blebs in 41% of NM-IIB-GFP–expressing cells, whereas filaments form in only 12 and 3% of cells expressing NM-IIA-GFP and NM-IIC1-GFP, respectively. These studies suggest that NM-II isoforms have differential roles in the bleb life cycle.

ON THE LIFE HISTORY AND VALIDITY OF THE SPECIES IN PSOROPTES, A GENUS OF MANGE MITES

1958 ◽  
Vol 36 (6) ◽  
pp. 905-929 ◽  
Author(s):  
Gordon K. Sweatman
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Host Specificity ◽  
Individual Susceptibility ◽  
Different Types

The stages in the life cycle of P. cuniculi and other species or varieties in the genus are described. Host specificity currently attributed to the different types in Psoroptes is disproved, but differences exist in individual susceptibility. The six auricular types of psoroptic mites are reduced to two, and the five kinds of body mites to four. A dendrogram is included which shows the relations between the genera and species in Psoroptidae.

Modeling Competition over Product Life Cycles

2015 ◽  
Vol 32 (04) ◽  
pp. 1550021 ◽  
Author(s):  
Ka Ching Chan ◽  
Terry M. Mills
Keyword(s):  
Life Cycle ◽  
Product Life Cycle ◽  
Life Cycles ◽  
Valuable Insight ◽  
Mobile Telecommunication ◽  
Product Life ◽  
Market Growth ◽  
Product Life Cycles ◽  
Market Shares ◽  
Different Types

This paper presents a mathematical model, linking the classical Markov models for brand switching and models for product life cycles, to forecast competition analysis and market share. This integrated model can be used to forecast market shares of all competitors, and their market shares, including customers retained, customers gained from market growth, and customers gained from competitors over the product life cycle. Such information provides forecasters with valuable insight about their market positions. The model is generic and can be applied to different types of products and services, under different types and patterns of product life cycle curves. A numerical example on a typical mobile telecommunication industry is used to illustrate the application of the proposed approach.

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