Flower Visitors as Cheats and the Plants’ Responses

2011 ◽  
Author(s):  
Pat Willmer
Keyword(s):  
Flower Visitors ◽  
Chemical Deterrents ◽  
Physical Barriers ◽  
Pollen Theft ◽  
Ambush Predators

This chapter describes some of the kinds of cheating committed by flower visitors and what plants can do to avoid the costs of being cheated. While both plants and visitors have many ways of cheating, the diversity and deviousness of cheating by the plants seem to be substantially greater than the surreptitious stealing and ambushing that goes on in the animals. This is not surprising when considered in terms of the so-called life-dinner principle, and what each participant has at stake. The chapter begins with a discussion of how animals cheat by means of floral theft and thus get rewards without effecting pollination, including nectar theft, pollen theft, and florivory. It then examines three main options for defending plants against theft: physical barriers, chemical deterrents, and bribes. It also explains the overall effects of theft on flowers and concludes with an analysis of floral exploitation by hitchhikers and ambush predators.

Flow Pattern Analysis of Constructed Wetlands Treating Landfill Leachate

1999 ◽  
Vol 40 (3) ◽  
pp. 309-315 ◽  
Author(s):  
Jonathan K. Rash ◽  
Sarah K. Liehr
Keyword(s):  
Constructed Wetlands ◽  
Vertical Mixing ◽  
Subsurface Flow ◽  
Free Water ◽  
Chemical Reactor ◽  
Operating Conditions ◽  
Conservative Tracer ◽  
Residence Time Distributions ◽  
Physical Barriers ◽  
Interior Points

Three series of tracer studies were performed on three constructed wetlands at the New Hanover County Landfill near Wilmington, North Carolina, USA. One vegetated free water surface wetland (FWS-R), one vegetated subsurface flow wetland (SSF-R), and one unvegetated control subsurface flow wetland (SSF-C) were studied. A conservative tracer, lithium chloride, was used to study the chemical reactor behavior of these wetlands under normal operating conditions. Results indicated that short-circuiting is quite common in SSF wetlands, while FWS wetlands are well-mixed and not as subject to short-circuiting. These results were obtained from and reinforced with tracer measurements at interior points in these wetlands, analysis of residence time distributions from two different formulations, and the construction of residence volume distributions. The short-circuiting in the SSF wetlands can be attributed to the following: (1) Vertical mixing is inhibited by a combination of physical barriers and density gradients caused by rainfall and runoff dilution of the upper layer; and (2) Leachate is drawn from the bottom of the wetland, causing it to further prefer a flow path along the bottom.

Endometrial Regeneration in Asherman's Syndrome: Clinical and Translational evidence of Stem Cell Therapies

2019 ◽  
Vol 14 (6) ◽  
pp. 454-459
Author(s):  
Xuejing Hou ◽  
Ying Liu ◽  
Isabelle Streuli ◽  
Patrick Dällenbach ◽  
Jean Dubuisson ◽  
...  
Keyword(s):  
Stem Cell ◽  
Molecular Mechanisms ◽  
Uterine Cavity ◽  
Stem Cell Therapies ◽  
Intrauterine Adhesions ◽  
Asherman’S Syndrome ◽  
Cell Therapies ◽  
Fibrotic Process ◽  
Physical Barriers

Asherman’s Syndrome or Intrauterine adhesions is an acquired uterine condition where fibrous scarring forms within the uterine cavity, resulting in reduced menstrual flow, pelvic pain and infertility. Until recently, the molecular mechanisms leading to the formation of fibrosis were poorly understood, and the treatment of Asherman’s syndrome has largely focused on hysteroscopic resection of adhesions, hormonal therapy, and physical barriers. Numerous studies have begun exploring the molecular mechanisms behind the fibrotic process underlying Asherman’s Syndrome as well as the role of stem cells in the regeneration of the endometrium as a treatment modality. The present review offers a summary of available stem cell-based regeneration studies, as well as highlighting current gaps in research.

scholarly journals Evaluation of Physical Barriers to Protect Ponderosa Pine Seedlings from Pocket Gophers

1999 ◽  
Vol 14 (3) ◽  
pp. 164-168 ◽  
Author(s):  
Michael J. Pipas ◽  
Gary W. Witmer
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Seedling Mortality ◽  
Pocket Gophers ◽  
Thomomys Talpoides ◽  
Pine Seedlings ◽  
Physical Barriers ◽  
Growth Of Seedlings ◽  
Medium Weight ◽  
Better Than

Abstract A 2 yr study on the Rogue River and Mt. Hood National Forests in Oregon evaluated physical barriers for protection of Pinus ponderosa seedlings against damage by Thomomys talpoides. Seedlings protected with one of three weights of: (1) plastic mesh tubing (Vexar®) or (2) sandpapertubing (Durite®) were evaluated against control seedlings. On the Rogue River sites, Vexar® seedlings had the highest survival (62.6%), followed by the controls (59.1%), then Durite® seedlings (17.9%). Gophers were the primary cause of death for the Vexar® seedlings, versus desiccation for the Durite® seedlings. On the Mt. Hood sites, heavyweight Vexar® seedlings had the highest survival (35.4%), medium-weight Durite® seedlings the lowest (2.7%). Seedling mortality caused by gophers was highest for controls (70.2%), followed by light-weight (62.2%) and heavy-weight (53.9%) Vexar® treatments. Overall survival was low (Rogue River = 42%, Mt. Hood = 19.8%). Growth was greatest for the control seedlings but only significantly greater than growth of Durite® seedlings on the Rogue River sites. Growth of seedlings was not compromised by the Vexar® tubing. Although neither type of tubing was highly protective, Vexar® tubes performed better than Durite® tubes. West. J. Appl. For. 14(3):164-168.

scholarly journals Mesenchymal stem cells and oncolytic viruses: joining forces against cancer

2021 ◽  
Vol 9 (2) ◽  
pp. e001684
Author(s):  
Rafael Moreno
Keyword(s):  
Stem Cells ◽  
Clinical Trials ◽  
Mesenchymal Stem Cells ◽  
Immune System ◽  
Oncolytic Viruses ◽  
Immunogenic Cell Death ◽  
The Past ◽  
Physical Barriers ◽  
Immunogenic Properties ◽  
New Strategies

The development of oncolytic viruses (OVs) has increased significantly in the past 20 years, with many candidates entering clinical trials and three of them receiving approval for some indications. Recently, OVs have also gathered interest as candidates to use in combination with immunotherapies for cancer due to their immunogenic properties, which include immunogenic cell death and the possibility to carry therapeutic transgenes in their genomes. OVs transform non-immunogenic ‘cold’ tumors into inflamed immunogenic ‘hot’ tumors, where immunotherapies show the highest efficacy. However, in monotherapy or in combination with immunotherapy, OVs face numerous challenges that limit their successful application, in particular upon systemic administration, such as liver sequestration, neutralizing interactions in blood, physical barriers to infection, and fast clearance by the immune system. In this regard, the use of mesenchymal stem cells (MSCs) as cells carrier for OV delivery addresses many of these obstacles acting as virus carriers and factories, expressing additional transgenes, and modulating the immune system. Here, I review the current progress of OVs-loaded MSCs in cancer, focusing on their interaction with the immune system, and discuss new strategies to improve their therapeutic efficacy.

scholarly journals Inequality is rising where social network segregation interacts with urban topology

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gergő Tóth ◽  
Johannes Wachs ◽  
Riccardo Di Clemente ◽  
Ákos Jakobi ◽  
Bence Ságvári ◽  
...  
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Network Structure ◽  
Urban Geography ◽  
Online Social Network ◽  
Stage Model ◽  
Significant Relationships ◽  
Social Segregation ◽  
Social Network Structure ◽  
Physical Barriers

AbstractSocial networks amplify inequalities by fundamental mechanisms of social tie formation such as homophily and triadic closure. These forces sharpen social segregation, which is reflected in fragmented social network structure. Geographical impediments such as distance and physical or administrative boundaries also reinforce social segregation. Yet, less is known about the joint relationships between social network structure, urban geography, and inequality. In this paper we analyze an online social network and find that the fragmentation of social networks is significantly higher in towns in which residential neighborhoods are divided by physical barriers such as rivers and railroads. Towns in which neighborhoods are relatively distant from the center of town and amenities are spatially concentrated are also more socially segregated. Using a two-stage model, we show that these urban geography features have significant relationships with income inequality via social network fragmentation. In other words, the geographic features of a place can compound economic inequalities via social networks.

scholarly journals COVID-19 PANDEMIC UPDATES AND PERSPECTIVES. NEED FOR AN INTEGRATED AND EQUITABLE APPROACH.

2021 ◽  
Author(s):  
Grigoris Gerotziafas ◽  
Mariella Catalano ◽  
Ioannis Theodorou ◽  
Patrick van Dreden ◽  
Vincent Marechal ◽  
...  
Keyword(s):  
Mitigation Strategies ◽  
World Health ◽  
Learning Technology ◽  
Pharmacological Interventions ◽  
Health Crisis ◽  
Patients At Risk ◽  
Physical Barriers ◽  
Risk Of Disease ◽  
One Year ◽  
Health Organization

One year after the declaration of the COVID-19 pandemic by the World Health Organization (WHO) and despite the implementation of mandatory physical barriers and social distancing, humanity remains challenged by a long-lasting and devastating public health crisis. Non-pharmacological interventions (NPI) are efficient mitigation strategies. The success of these intense NPI is dependent on the approval and commitment of the population. The launch of a mass vaccination program in many countries in late December 2020 with mRNA vaccines, adenovirus-based vaccines, and inactivated virus vaccines has generated hope for the end of the pandemic. Current issues: The continuous appearance of new pathogenic viral strains and the ability of vaccines to prevent infection and transmission raise important concerns as we try to achieve community immunity against SARS-CoV-2 and its variants. The need of a second and even third generation of vaccines and the possibility of potentially harmful side-effects of the vaccines (i.e. venous thromboembolism ) have already been acknowledged. Perspectives: There is a critical and urgent need for a balanced and integrated strategy for the management of the COVID-19 outbreaks organized on three axes: (1) Prevention of the SARS-CoV-2 infection, (2) Detection and early diagnosis of patients at risk of disease worsening, and (3) Anticipation of medical care (PDA). Conclusion: The “PDA strategy” integrated into state policy for the support and expansion of health systems and introduction of digital organization (i.e. telemedicine, artificial intelligence and machine learning technology) is of major importance for the preservation of citizens’ health and life world-wide.

scholarly journals Doxycycline-Doped Polymeric Membranes Induced Growth, Differentiation and Expression of Antigenic Phenotype Markers of Osteoblasts

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1063
Author(s):  
Manuel Toledano-Osorio ◽  
Francisco J. Manzano-Moreno ◽  
Manuel Toledano ◽  
Antonio L. Medina-Castillo ◽  
Victor J. Costela-Ruiz ◽  
...  
Keyword(s):  
Composite Membranes ◽  
Polymeric Membranes ◽  
Potential Candidate ◽  
Polymeric Scaffold ◽  
Hla Dr ◽  
Proliferation And Differentiation ◽  
Physical Barriers ◽  
Antigenic Phenotype ◽  
Biomimetic Membrane ◽  
Phenotype Markers

Polymeric membranes are employed in guided bone regeneration (GBR) as physical barriers to facilitate bone in-growth. A bioactive and biomimetic membrane with the ability to participate in the healing and regeneration of the bone is necessary. The aim of the present study was to analyze how novel silicon dioxide composite membranes functionalized with zinc or doxycycline can modulate the osteoblasts’ proliferation, differentiation, and expression of selected antigenic markers related to immunomodulation. Nanostructured acrylate-based membranes were developed, blended with silica, and functionalized with zinc or doxycycline. They were subjected to MG63 osteoblast-like cells culturing. Proliferation was assessed by MTT-assay, differentiation by evaluating the alkaline phosphatase activity by a spectrophotometric method and antigenic phenotype was assessed by flow cytometry for selected markers. Mean comparisons were conducted by one-way ANOVA and Tukey tests (p < 0.05). The blending of silica nanoparticles in the tested non-resorbable polymeric scaffold improved the proliferation and differentiation of osteoblasts, but doxycycline doped scaffolds attained the best results. Osteoblasts cultured on doxycycline functionalized membranes presented higher expression of CD54, CD80, CD86, and HLA-DR, indicating a beneficial immunomodulation activity. Doxycycline doped membranes may be a potential candidate for use in GBR procedures in several challenging pathologies, including periodontal disease.

scholarly journals Natural barriers: waterfall transit by small flying animals

2020 ◽  
Vol 7 (8) ◽  
pp. 201185
Author(s):  
Victor M. Ortega-Jimenez ◽  
Eva C. Herbst ◽  
Michelle S. Leung ◽  
Robert Dudley
Keyword(s):  
Complex Dynamics ◽  
Sister Group ◽  
The Body ◽  
Heterogeneous Structure ◽  
Flight Behaviour ◽  
Physical Constraints ◽  
Physical Barriers ◽  
Translational Speed ◽  
Geomorphological Features ◽  
Stroke Amplitude

Waterfalls are conspicuous geomorphological features with heterogeneous structure, complex dynamics and multiphase flows. Swifts, dippers and starlings are well-known to nest behind waterfalls, and have been reported to fly through them. For smaller fliers, by contrast, waterfalls seem to represent impenetrable barriers, but associated physical constraints and the kinematic responses of volant animals during transit are unknown. Here, we describe the flight behaviour of hummingbirds (the sister group to the swifts) and of various insect taxa as they fly through an artificial sheet waterfall. We additionally launched plastic balls at different speeds at the waterfall so as to assess the inertial dependence of sheet penetration. Hummingbirds were able to penetrate the waterfall with reductions in both their translational speed, and stroke amplitude. The body tilted more vertically and exhibited greater rotations in roll, pitch and yaw, along with increases in tail spread and pitch. The much smaller plastic balls and some flies moving at speeds greater than 2.3 m s −1 and 1.6 m s −1 , respectively, also overcame effects of surface tension and water momentum and passed through the waterfall; objects with lower momentum, by contrast, entered the sheet but then fell along with the moving water. Waterfalls can thus represent impenetrable physical barriers for small and slow animal fliers, and may also serve to exclude both predators and parasites from nests of some avian taxa.

scholarly journals Corrigendum to “The importance of flower visitors not predicted by floral syndromes”

2010 ◽  
Vol 76 (2) ◽  
pp. 419
Author(s):  
D. Geelhand de Merxem ◽  
B. Borremans ◽  
M.L. de Jäger ◽  
T. Johnson ◽  
M. Jooste ◽  
...  
Keyword(s):  
Flower Visitors ◽  
Floral Syndromes
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