Floral morphology of Eucalyptus leucoxylon (Myrtaceae) facilitates pollination by lorikeet (Aves: Psittacidae) tongues

2017 ◽  
Vol 65 (4) ◽  
pp. 368 ◽  
Author(s):  
Joseph P. Zilko ◽  
Susan E. Hoebee ◽  
Trevor J. Edwards
Keyword(s):  
Floral Morphology ◽  
Pollen Grains ◽  
Adhesive Tape ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Pollen Transport ◽  
Male Phase ◽  
The Mean ◽  
Short Time ◽  
Generalist Pollination

Bird pollination is particularly common and widespread in the southern regions of Australia. Despite some eucalypts being heavily frequented by birds, they are usually considered to have a generalist pollination system because of their apparently unspecialised floral morphology. A few species possess protandrous anthers that dehisce within a tightly furled dome of filaments. We hypothesised that this facilitates pollen transport via the brush tongues of lorikeets. Using Eucalyptus leucoxylon F.Muell. and five captive rainbow lorikeets (Trichoglossus hematodus) as a model, we demonstrated that lorikeets remove significant quantities of pollen from flowers with inflexed filaments in a short time (30 min), compared with bagged control flowers (Mann–Whitney U test, Z = 165.4, d.f. = 29, P = 0.008). Some of this pollen is deposited on stigmas by the tongue, which is the organ that most regularly and reliably contacts stigmas. The mean number of pollen grains deposited on stigmas by each bird was as high as 121.2. Adhesive tape contacted by the tongue during foraging removed up to 2104 pollen grains, which was significantly greater than for uncontacted control tape (Mann–Whitney U test, Z = 110, d.f. = 21, P < 0.001). Scanning electron micrograph imaging of a lorikeet tongue showed many pollen grains that had been transferred onto its keratin papillae, which is likely to have contributed to high carryover rates by retaining pollen for a substantial amount of time. Minimal pollen is available for generalist pollination once the filaments unfurl. It appears highly unlikely that insects are able to access pollen from these male-phase flowers and inflexed filaments may therefore fulfil an exclusionary role.

scholarly journals Potential Drift of Pollen of Cycas micronesica on the Island of Guam: A Comparative Study

HortScience ◽  
2015 ◽  
Vol 50 (7) ◽  
pp. 1106-1117 ◽  
Author(s):  
Trenton Hamada ◽  
Irene Terry ◽  
Robert Roemer ◽  
Thomas E. Marler
Keyword(s):  
Comparative Study ◽  
Pollen Grains ◽  
Pollen Size ◽  
Trade Winds ◽  
Pollen Transport ◽  
Wind Velocities ◽  
Plant Characteristics ◽  
The Mean ◽  
Angiosperm Species ◽  
Pollination Mode

We have investigated the potential movement on air currents of pollen from Guam’s native cycad, Cycas micronesica, proposed as ambophilic. We measured wind velocities and directions in different cycad habitats that vary in their exposure to trade winds, determined pollen settling velocities, and then modeled the potential horizontal pollen drift distance in each habitat. Similar measurements were performed on several entomophilous Zamia cycads and six zoophilous tropical trees used in horticulture or landscaping. All cycad species’ pollen exhibited relatively slow mean settling velocities (0.73–1.29 cm·s−1) with C. micronesica pollen in the middle of this range. Our models predicted that wind in more open habitats with wind directions east northeast (ENE) to northeast (NE) and velocities >2 m·s−1 could transport C. micronesica pollen, either single grains or clumps, hundreds of meters downwind from the pollen source before falling 1 or 2 m. In forested habitats and at typical heights of cycad cones in the understory, the mean wind velocities ranged from <0.03 m·s−1 to ≈1 m·s−1. In habitats with mean winds ≥0.2 m·s−1, models predicted pollen transport distances of tens of meters from the pollen source. In sheltered habitats with velocities near 0.03 m·s−1, the potential wind transport of pollen was limited to less than a few meters, suggesting that wind would be an ineffective vector in such areas. Pollen grains of all angiosperm species were larger except one, and the species with larger grains had settling velocities 3–26 times faster than that of cycad pollens. Even so, winds in most Guam environments could transport pollen of most angiosperm species over 50 m before falling 1 m. In summary, the results suggested that pollen size, clumping tendencies, and drift of most of these species do not preclude a role for wind in moving pollen in habitats exposed to trade winds, and that other physical and plant characteristics affect their pollination mode. For C. micronesica, these pollen and plant attributes do not preclude entomophily, and insects are likely required in the deep understory where cycads are present.

Analytical and High-Resolution EM Study of Crystalline Phases formed at Metal-Ceramic Interface

1990 ◽  
Vol 48 (2) ◽  
pp. 426-427
Author(s):  
N. Merk ◽  
A. P. Tomsia ◽  
G. Thomas
Keyword(s):  
Cross Section ◽  
Dissimilar Materials ◽  
Ceramic Materials ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Structural Applications ◽  
Metal Ceramic ◽  
The Subject ◽  
Ceramic Compounds ◽  
Scanning Electron

A recent development of new ceramic materials for structural applications involves the joining of ceramic compounds to metals. Due to the wetting problem, an interlayer material (brazing alloy) is generally used to achieve the bonding. The nature of the interfaces between such dissimilar materials is the subject of intensive studies and is of utmost importance to obtain a controlled microstructure at the discontinuities to satisfy the demanding properties for engineering applications . The brazing alloy is generally ductile and hence, does not readily fracture. It must also wett the ceramic with similar thermal expansion coefficient to avoid large stresses at joints. In the present work we study mullite-molybdenum composites using a brazing alloy for the weldment.A scanning electron micrograph from the cross section of the joining sequence studied here is presented in Fig. 1.

Preparation and Characterization of a Novel Mixed Functional Cationic Exchange Copolymer Microsphere as Drug Carrier

2012 ◽  
Vol 476-478 ◽  
pp. 2288-2291 ◽  
Author(s):  
Kaewnapa Wongsermsin ◽  
Praneet Opanasopit ◽  
Tanasait Ngawhirunpat ◽  
Prasert Akkaramongkolporn
Keyword(s):  
Drug Carrier ◽  
Gastric Ph ◽  
The Novel ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Cationic Exchange ◽  
The Fourier Transform ◽  
Release Characteristic ◽  
Dextromethorphan Hydrobromide

The objective of the present study was to prepare a novel mixed functional cationic exchange copolymer microsphere containing methyl methacrylic acid and sulfonated styrene crosslinked with divinylbenzene. The emulsion polymerization was used to prepare the cationic exchange copolymer microsphere which was characterized by the scanning electron micrograph (SEM) and the fourier transform infrared spectroscopy (FTIR). The release characteristic of the loaded drug i.e. dextromethorphan hydrobromide from the copolymer microsphere was studied under both simulated gastric (pH 1.2) and intestinal (pH 6.8) conditions. The result showed that the drug released from the novel copolymer microsphere depended on the pH of the release media.

Bacterial biofilm adherence to middle-ear ventilation tubes: scanning electron micrograph images and literature review

2007 ◽  
Vol 121 (10) ◽  
pp. 993-997 ◽  
Author(s):  
M Barakate ◽  
E Beckenham ◽  
J Curotta ◽  
M da Cruz
Keyword(s):  
Middle Ear ◽  
Bacterial Biofilm ◽  
Electron Micrograph ◽  
Ventilation Tube ◽  
Scanning Electron Micrograph ◽  
Chronic Infections ◽  
Middle Ear Ventilation ◽  
Conventional Antibiotics ◽  
Scanning Electron

Introduction: The organisms that cause many device-related and other chronic infections actually grow in biofilms in or on these devices. We sought to examine the role of biofilm formation in chronic middle-ear ventilation tube infection.Case report: Scanning electron micrograph images are presented which demonstrate biofilm on a middle-ear ventilation tube removed from a five-year-old child's chronically discharging ear. A review of the relevant international literature explores the role of biofilms in chronic infection and discusses potential intervention strategies.Conclusion: Biofilms may be responsible for chronic middle-ear ventilation tube infection that resists treatment with conventional antibiotics.

scholarly journals Distribution-Free Model for Ambulance Location Problem with Ambiguous Demand

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Feng Chu ◽  
Lu Wang ◽  
Xin Liu ◽  
Chengbin Chu ◽  
Yang Sui
Keyword(s):  
Probability Distribution ◽  
Location Problem ◽  
Service Level ◽  
Mixed Integer ◽  
Distribution Free ◽  
Demand Information ◽  
The Mean ◽  
Constrained Model ◽  
Short Time ◽  
Ambulance Location

Ambulance location problem is a key issue in Emergency Medical Service (EMS) system, which is to determine where to locate ambulances such that the emergency calls can be responded efficiently. Most related researches focus on deterministic problems or assume that the probability distribution of demand can be estimated. In practice, however, it is difficult to obtain perfect information on probability distribution. This paper investigates the ambulance location problem with partial demand information; i.e., only the mean and covariance matrix of the demands are known. The problem consists of determining base locations and the employment of ambulances, to minimize the total cost. A new distribution-free chance constrained model is proposed. Then two approximated mixed integer programming (MIP) formulations are developed to solve it. Finally, numerical experiments on benchmarks (Nickel et al., 2016) and 120 randomly generated instances are conducted, and computational results show that our proposed two formulations can ensure a high service level in a short time. Specifically, the second formulation takes less cost while guaranteeing an appropriate service level.

scholarly journals Studies on the Structure of Flowers and Inflorescences of Cornelian Cherry (Cornus mas L.)

2012 ◽  
Vol 40 (2) ◽  
pp. 53 ◽  
Author(s):  
Cevriye MERT
Keyword(s):  
Pollen Grains ◽  
Flower Morphology ◽  
Flower Number ◽  
Flower Buds ◽  
Cornelian Cherry ◽  
Cornus Mas ◽  
Conducting Tissue ◽  
Stereo Microscope ◽  
The Mean ◽  
Scanning Electron

This study reports on the arrangement of flower buds and structure of floral organs of cornelian cherry (Cornus mas L.) cultivars local to Turkey. The local cultivars were investigated under stereo microscope, light microscope, and scanning electron microscope (SEM). The results indicate that each node has two oppositely positioned buds on 1-year-old shoot. Inflorescences resembled the umbel structure that enclosed four (two sets of oppositely oriented) bud scales. The mean flower number varied between 16.3 and 19.9 per cluster among the cultivars. The flowers resembled the hermaphrodite type and one flower was found to have four rudimentary sepals, four petals, four stamens, and one pistil. The stamens were noted to be arranged around the base of the ovary. Each normal anther was observed to have two pollen-producing theca, and each theca was found to have two locules. The number of pollen grains per anther varied between 1380 and 4240 among the genotypes. The pistil was noted to have a deeply hollowed papillate stigmatic surface, and the central part of the style had conducting tissue. The ovarium part of the pistil was found to be surrounded by the nectary tissue, inferior type, and had two atropous ovules. The fruit resembled single-seeded, stone fruit type. This study is the first detailed study on the flower morphology and inflorescences of the cornelian cherry cultivars in Turkey.

scholarly journals A new species, Stemonitis sichuanensis, and a newly recorded species, Stemonitis marjana (Myxogastria) from China

Phytotaxa ◽  
2016 ◽  
Vol 258 (2) ◽  
pp. 195 ◽  
Author(s):  
ZHANG BO ◽  
LI YU
Keyword(s):  
New Species ◽  
New Record ◽  
Sichuan Province ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Natural Reserve ◽  
A New Species ◽  
Scanning Electron

A new species, Stemonitis sichuanensis, collected in Gexigou National Natural Reserve, Sichuan province, China, is described herein. This new species has a columella that usually ends in an ovoid to triangular expansion at the apex of the sporotheca and small spores (about 6–7 μm in diam.). We present a scanning electron micrograph study of S. sichuanensis and a key to the species in the genus Stemonitis. Holotype specimens of S. sichuanensis are deposited in the Herbarium of the Mycological Institute of Jilin Agricultural University (HMJAU), Changchun, China. We also report a new record of another species of Stemonitis, S. marjana Y. Yamam., in this paper, specimens of which are also deposited in the HMJAU.

scholarly journals The Polar Fields and Time Fluctuations of the General Magnetic Field of the Sun

1971 ◽  
Vol 43 ◽  
pp. 675-695 ◽  
Author(s):  
A. B. Severny
Keyword(s):  
Magnetic Field ◽  
Close Agreement ◽  
Present Knowledge ◽  
Short Time Scale ◽  
The Sun ◽  
Statistical Nature ◽  
General Magnetic Field ◽  
Short Period ◽  
The Mean ◽  
Short Time

In an attempt to summarize the present knowledge on the general magnetic field (gmf) of the Sun we pointed out the fine structure and the statistical nature of the gmf as one of its most important properties. The dipole-like behaviour of the mean polar field strengths is combined sometimes (since 1964) with a bias of the S-polarity flux for both poles. Highly uneven distribution of gmf with latitude and longitude, the disappearance of gmf at the South pole for months, and short period, almost synchronous at both poles, variations in the sign of gmf are pointed out. The fluctuations with time of the mean magnetic field of the Sun seen as a star (as well as mf at different latitudes) shows periodicity connected with the rotation of the Sun and very close agreement with the fluctuations of the interplanetary field (sector structure). The effect of faster rotation of N-polarities as compared with S-polarities as well as the bias of mean solar as well as interplanetary S-polarity fields are also pointed out. The possibility of short time-scale (hours) intrinsic changes in the local pattern of gmf is demonstrated.

scholarly journals Pre- and intraoperative acoustic and functional assessment of the novel APrevent® VOIS implant during routine medialization thyroplasty

2019 ◽  
Vol 277 (3) ◽  
pp. 809-817
Author(s):  
Guan-Yuh Ho ◽  
Matthias Leonhard ◽  
Doris-Maria Denk-Linnert ◽  
Berit Schneider-Stickler
Keyword(s):  
Vocal Fold ◽  
Type I ◽  
The Novel ◽  
Glottal Closure ◽  
Medialization Thyroplasty ◽  
Before And After ◽  
Glottal Insufficiency ◽  
The Mean ◽  
Acoustic Analyses ◽  
Short Time

Abstract Purpose Persistent unilateral vocal fold paralysis (UFVP) with glottal insufficiency often requires type I medialization thyroplasty (MT). Previous implants cannot be adjusted postoperatively if necessary. The newly developed APrevent® VOIS implant (VOIS) can provide postoperative re-adjustment to avoid revision MT. The objective of this pilot study is to evaluate the VOIS intraoperatively concerning voice improvement, surgical feasibility and device handling. Methods During routine MT, VOIS was applied short time in eight patients before the regular implantation of the Titanium Vocal Fold Medialization Implant (TVFMI™). In all patients, perceptual voice sound analysis using R(oughness)–B(reathiness)–H(oarseness)-scale, measurement of M(aximum)–P(honation)–T(ime) and glottal closure in videolaryngoscopy were performed before and after implanting VOIS/TVFMI™. Acoustic analyses of voice recordings were performed using freeware praat. Surgical feasibility, operative handling and device fitting of VOIS and TVFMI™ were assessed by the surgeon using V(isual)-A(nalog)-S(cale). Data were statistically analyzed with paired t test. Result All patients showed significant improvement of voice sound parameters after VOIS/TVFMI™ implantation. The mean RBH-scale improved from preoperative R = 2.1, B = 2.3, H = 2.5 to R = 0.6, B = 0.3, H = 0.8 after VOIS and R = 0.5, B = 0.3, H = 0.8 after TVFMI™ implantation. The mean MPT increased from preoperative 7.9 to 14.6 s after VOIS and 13.8 s after TVFMI™ implantation. VOIS/TVFMI™ achieved complete glottal closure in 7/8 patients. The satisfaction with intraoperative device fitting and device handling of VOIS was as good as that of TVFMI™. Conclusion The novel APrevent® VOIS implant showed similar intraoperative voice improvement compared to routinely used TVFMI™ without adverse device events and with safe device fitting.

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