Polar View Research Articles

Pollen morphology of the genus Cota J.Gay (Asteraceae) in Turkey

Pollen morphology of 22 Cota taxa naturally distributed in Turkey was investigated to describe their pollen features and to evaluate the diagnostic value of pollen characters for systematic purposes using light microscopy and scanning electron microscopy. Pollen grains of Cota are radially symmetrical and isopolar. Their shape is oblate-spheroidal with the polar axes 21.6–34.56 μm and the equatorial axes 23.04–33.6 μm. The pollens are trizonocolporate. The outline is elliptic in equatorial view and triangular in polar view; amb intersemiangular. Exine sculpturing is echinate. Inter-spinal region exhibits perforate and microreticulate–perforate ornamentations. Numerical analysis revealed that dimensions of the pollen grains and surface ornamentation are the most reliable characters for delimiting the taxa within the genus.

Conspecific Pollen on Insects Visiting Female Flowers on the Oak Parasite Phoradendron coryae (Viscaceae)

Phoradendron coryae (Viscaceae) is a dioecious, parasitic plant on oak trees and shrubs in Quercus (Fagaceae), and it occurs from Arizona to Texas and into northern Mexico. The species produces minute spherical flowers during summer. Dioecious flowering requires pollinating insects to carry pollen from male to female plants. I investigated the pollination of P. coryae parasitizing Quercus turbinella shrubs at 3 sites at different elevations in the Cerbat Mountains of northwestern Arizona during August–September 2015. I examined pollen from male flowers, aspirated insects landing on female flowers, and counted conspecific pollen grains carried by insects. The tricolpate pollen of P. coryae was semiangular to subangular in polar view and circular to depressed oval in equatorial view. Female flowers were visited by 2 species of Coleoptera in 2 families, 6 species of Diptera in 6 genera and 3 families, and 1 species of Hymenoptera. Insects on flowers were extremely small (most <3 mm in length), and nearly all (99%) of the pollen carried by insects was from P. coryae. Conspecific pollen was found on 67% of the insects identified. Pollen loads were low, with only 25% of the insects carrying ≥5 grains. The beetle Attalus futilis (Melyridae) was the most frequently aspirated species, comprising 71% of the insects collected and occurring at all 3 sites. Most A. futilis (64%) carried P. coryae pollen. The second most frequently collected insects were 2 species of Hippelates and Liohippelates flies (Chloropidae). The Liohippelates carried the most P. coryae pollen. Other insects with pollen included 2 additional species of Chloropidae, 2 species of flies in Tachinidae and Tephritidae, a species of beetle in Chrysomelidae, and a species of parasitic wasp in Figitidae. Phoradendron coryae appeared to be pollinated mostly by A. futilis beetles due to their apparent abundance and by Liohippelates flies due to their relatively high pollen loads.

Pollen morphology of Carapa species (Meliaceae) from the Brazilian Amazon

Abstract The crabwood (Carapa) represents an important source of natural resources. The objective of this work was to study the pollen morphology of the three species of Carapa (Meliaceae) registered in the Brazilian Amazon. The pollen grains were obtained from floral buds, pistillate and staminate flowers of Carapa guianensis, C. surinamensis and C. vasquezii. In order to explore the taxonomic implications of the pollen study for these species of Carapa, lactic acetolysis method was used for light microscopy study. Furthermore, the non-acetolyzed material was used in the study of the scanning electron microscopy. It was found that the three Carapa species present little variations in pollen morphology. Compared to the other species this study, Carapa vasquezii has higher values for the length and width of endoaperture; however, it has lower values for polar and equatorial diameter, equatorial diameter in polar view and apocolpium side.

Проблемы реализации процессуальных обязанностей подозреваемого

In modern Russian society there is no holistic, single view of social polarization. It is caused by a number of controversial compound of cultural traditions. There is no single relation to gender inequality. In these circumstances, the younger generations are trying to build a compensatory strategies of gender relations. These strategies are not always adequate, that becomes one of the family crisis factors.

Гендерное неравенство в контексте социальной поляризации российского общества: молодежный аспект

In modern Russian society there is no holistic, single view of social polarization. It is caused by a number of controversial compound of cultural traditions. Ther is also no single relation to gender inequality. In these circumstances the younger generations are trying to build a compensatory strategies of gender relations. These strategies are not always adequate and this fact becomes one of of family crisis factors.

Design of the polar neutron-imaging aperture for use at the National Ignition Facility.

The installation of a neutron imaging diagnostic with a polar view at the National Ignition Facility (NIF) required design of a new aperture, an extended pinhole array (PHA). This PHA is different from the pinhole array for the existing equatorial system due to significant changes in the alignment and recording systems. The complex set of component requirements, as well as significant space constraints in its intended location, makes the design of this aperture challenging. In addition, lessons learned from development of prior apertures mandate careful aperture metrology prior to first use. This paper discusses the PHA requirements, constraints, and the final design. The PHA design is complex due to size constraints, machining precision, assembly tolerances, and design requirements. When fully assembled, the aperture is a 15 mm × 15 mm × 200 mm tungsten and gold assembly. The PHA body is made from 2 layers of tungsten and 11 layers of gold. The gold layers include 4 layers containing penumbral openings, 4 layers containing pinholes and 3 spacer layers. In total, there are 64 individual, triangular pinholes with a field of view (FOV) of 200 μm and 6 penumbral apertures. Each pinhole is pointed to a slightly different location in the target plane, making the effective FOV of this PHA a 700 μm square in the target plane. The large FOV of the PHA reduces the alignment requirements both for the PHA and the target, allowing for alignment with a laser tracking system at NIF.

Fast retrieval of calcification from sequential intravascular ultrasound gray-scale images.

Intravascular ultrasound (IVUS)-based tissue characterization is invaluable for the computer-aided diagnosis and interventional treatment of cardiac vessel diseases. Although the analysis of raw backscattered signals allows more accurate plaque characterization than gray-scale images, its applications are limited due to its nature of electrocardiogram-gated acquisition. Images acquired by IVUS devices that do not allow the acquisition of raw signals cannot be characterized. To address these limitations, we developed a method for fast frame-by-frame retrieval and location of calcification according to the jump features of radial gray-level variation curves from sequential IVUS gray-scale images. The proposed method consists of three main steps: (1) radial gray-level variation curves are extracted from each filtered polar view, (2) sequential images are preliminarily queried according to the maximal slopes of radial gray-level variation curves, and finally, (3) key frames that include calcification are selected through checking the gray-level features of successive pixel columns in the preliminary results. Experimental results with clinically acquired in vivo data sets indicate key frames that include calcification can be retrieved with the advantages of simplicity, high efficiency, and accuracy. Recognition results correlate well with manual characterization results obtained by experienced physicians and through virtual histology.

Moderator's view: Treatment of IgA nephropathy-getting comfortable with uncertainty.

A Polar Views discussion by Pozzi and Rauen et al. on the interpretation and clinical application of the recently published Supportive Versus Immunosuppressive Therapy of Progressive IgA Nephropathy (STOP-IgAN) trial has elucidated important points concerning potential strengths and weaknesses of this landmark randomized trial. This critical examination of the impact of steroid monotherapy or steroid plus an immunosuppressive (IS) agent compared with 'supportive' therapy with inhibitors of the renin-angiotensin system (RAS) has enhanced our appreciation of the importance of rigorous application of titrated RAS inhibition in high-risk patients with persistent proteinuria >0.75 g/day. At the same time, it brings a new level of uncertainty concerning the overall value and risk of steroid or steroid plus IS therapy in patients failing such 'supportive' therapy. Some of these uncertainties revolve on issues of study design, such as the duration of follow-up, participant stratification (particularly underlying pathology) and dosing regimens. It is hoped that additional trials, better methods of patient selection, improved surrogate end points and safer regimens will lead to less uncertainty over the best treatment practices. On balance, the STOP-IgAN trial raises some key concerns about the merits of steroid alone or steroid plus IS therapy for selected subjects with IgAN, but it does not by itself close the door on the utility of steroid monotherapy in subjects with high-risk IgAN, even as it further degrades the value of steroid plus IS, at least with sequential cyclophosphamide and azathioprine.

Pollen Morphology of Herbaceous Peonies with Different Ploidy Levels

The pollen morphology of 26 cultivars of herbaceous peony (Paeonia L.) was examined by scanning electron microscopy (SEM). Pollen grains of the cultivars were mostly subprolate to perprolate, tricolporate, or ellipsoidal in equatorial view, but rounded-trifid in polar view. The poles of pollen grains were mainly flat when viewed in cross-section and only a few appeared to have a circular or arc shape. In addition, the surface of the pollen grains was psilate, and the muri were partly or fully protuberant with a reticulate surface sculpture. However, the shapes and sizes of pollen grains as well as surface ornamentation varied significantly among cultivars with different chromosome numbers. The pollen grains from diploid cultivars were regular and full, and the reticulation holes were evenly distributed, while most of the pollen grains from triploid cultivars were empty flat shells with some heteromorphic pollen whose surface ornamentation was mostly rugulate-reticulate exine. The pollen grains from tetraploid cultivars were the largest although pollen morphology and surface ornamentation differed between Athena and Cream Delight. Six indices [polar axis length (P), equator axis length (E), P/E, pollen perforation diameter (D), ridge width (W), and D/W] were used in Q cluster analysis, which divided the 26 cultivars into three groups. Group I included eight diploid, four triploid, and one tetraploid cultivar. Group II included 12 triploid cultivars with complex genetic backgrounds. Group III included only one tetraploid cultivar Cream Delight. This work may provide an important palynological basis for studying taxonomy and hybrid breeding of herbaceous peony cultivars.

Moderator's view: Vitamin D deficiency treatment in advanced chronic kidney disease: a close look at the emperor's clothes.

Two recent vitamin D supplementation (ergocalciferol) trials in stage G5D CKD patients with vitamin D insufficiency showed that this sterol effectively increases serum 25-hydroxyvitamin D [25(OH)D] but fails to modify serum PTH and other clinical outcomes. The Pro side of this polar view emphasizes that the duration of these studies was too short to allow sensible analyses based on a clinical endpoint. Furthermore, he notes that in the second study, the use of active forms of vitamin D, phosphate binders and cinacalcet could have hindered appreciation of the effect of ergocalciferol supplementation per se The Con side produces an updated meta-analysis showing that inactive vitamin D forms largely fail to reduce serum PTH and affect various relevant endpoints, including muscle strength, functional capacity, quality of life and hospitalization. Studies suggesting an effect of inactive vitamin D forms in advanced CKD are either very small and mainly based on sequential, uncontrolled observations or inherently weak, simple pre/post studies. No biological or clinical evidence exists that 25(OH)D may exert meaningful effects in CKD patients who are being treated with active forms of vitamin D. Careful a etiologic studies based on the omics sciences, i.e. precise pathophysiological profiling of individual CKD patients followed by consequential, well-targeted intervention(s) in the precision medicine scenario, will likely provide a definitive answer to the lingering question of whether inactive vitamin D forms may have biological effects beyond those produced by their proximate metabolite 1,25-dihydroxyvitamin D3.

Con: Nutritional vitamin D replacement in chronic kidney disease and end-stage renal disease

Insufficiency of 25-hydroxyvitamin D [25(OH)D] is highly prevalent among patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD) and is a critical component in the pathogenesis of secondary hyperparathyroidism. Accordingly, current National Kidney Foundation-Kidney Disease Outcomes Quality Initiative and Kidney Disease: Improving Global Outcomes guidelines recommend the correction of hypovitaminosis D through nutritional vitamin D replacement as a first-step therapeutic approach targeting secondary hyperparathyroidism. In this Polar Views debate, we summarize the existing evidence, aiming to defend the position that nutritional vitamin D replacement is not evidence-based and should not be applied to patients with CKD. This position is supported by the following: (i) our meta-analysis of randomized controlled trials shows that whereas nutritional vitamin D significantly increases serum 25(OH)D levels relative to placebo, there is no evidence either in predialysis CKD or in ESRD that parathyroid hormone (PTH) is lowered; (ii) on the other hand, in randomized head-to-head comparisons, nutritional vitamin D is shown to be inferior to activated vitamin D analogs in reducing PTH levels; (iii) nutritional vitamin D is reported to exert minimal to no beneficial actions in a series of surrogate risk factors, including aortic stiffness, left ventricular mass index (LVMI), epoetin utilization and immune function among others; and (iv) there is no evidence to support a benefit of nutritional vitamin D on survival and other 'hard' clinical outcomes. Whereas nutritional vitamin D replacement may restore 25(OH)D concentration to near normal, the real target of treating vitamin D insufficiency is to treat secondary hyperparathyroidism, which is untouched by nutritional vitamin D. Furthermore, the pleotropic benefits of nutritional vitamin D remain to be proven. Thus, there is little, if any, benefit of nutritional vitamin D replacement in CKD.

Pollen morphology of Scorzonera (Asteraceae) in Turkey

The pollen morphology of 45 taxa belonging to 15 sections of the genus Scorzonera distributed in Turkey were studied with light and electron microscopies. The pollen is generally 3-zonocolporate. Pollen grains are oblate-spheroidal with the polar axes 23.2–59.2 µm and the equatorial axes 27–62.5 µm. The outline is more or less circular to slightly elliptic in equatorial view and triangular or obtuse-hexagonal in polar view; amb semiangular to intersemiangular. Sculpturing is echinolophate. The spines are commonly concave-conical with a broad basis, sides are straight or slightly convex with a subacute tapered apical portion. Numerical analysis showed that polar axes, equatorial axes and exine thickness are valuable variables for seperating the examined taxa.

He II λ4686 EMISSION FROM THE MASSIVE BINARY SYSTEM IN η CAR: CONSTRAINTS TO THE ORBITAL ELEMENTS AND THE NATURE OF THE PERIODIC MINIMA* † ‡ §

ABSTRACT Eta Carinae (η Car) is an extremely massive binary system in which rapid spectrum variations occur near periastron. Most notably, near periastron the He ii λ4686 line increases rapidly in strength, drops to a minimum value, then increases briefly before fading away. To understand this behavior, we conducted an intense spectroscopic monitoring of the He ii λ4686 emission line across the 2014.6 periastron passage using ground- and space-based telescopes. Comparison with previous data confirmed the overall repeatability of the line equivalent width (EW), radial velocities, and the timing of the minimum, though the strongest peak was systematically larger in 2014 than in 2009 by 26%. The EW variations, combined with other measurements, yield an orbital period of 2022.7 ± 0.3 days. The observed variability of the EW was reproduced by a model in which the line flux primarily arises at the apex of the wind–wind collision and scales inversely with the square of the stellar separation, if we account for the excess emission as the companion star plunges into the hot inner layers of the primary’s atmosphere, and including absorption from the disturbed primary wind between the source and the observer. This model constrains the orbital inclination to 135°–153°, and the longitude of periastron to 234°–252°. It also suggests that periastron passage occurred on T 0 = 2456874.4 ( &PlusMinus; 1.3 ?> days). Our model also reproduced EW variations from a polar view of the primary star as determined from the observed He ii &lambda; 4686 ?> emission scattered off the Homunculus nebula.

Pollen morphology of species of Graphistylis B. Nord. (Asteraceae) of Brazil

This paper presents the results of a palynological study of the species ofGraphistylis that were segregated fromSenecio (s.l.) (Seneciosect. Dichroa) and that are all endemic of Brazil. These species are found in mountainous regions of the states of Espirito Santo, Minas Gerais, Parana, Rio de Janeiro, Sao Paulo and Santa Catarina. The pollen grains of eight species were acetolyzed and analyzed and photographed using light microscopy. Unacetolyzed pollen grains were analyzed and photomicrographed using scanning electron microscopy. The current study undertook a palynologically analysis of Graphistylis in order to obtain information useful for making a better ranking of these genus. The results show medium-sized pollen grains that were oblate spheroidal or prolate spheroidal and subtriangular amb and tricolporate. The pollen grains possessed lalongate endoapertures with a median constriction and the presence of costa in only two species. The exine is echinate with a varying number of spines in the apocolpium region around the central spine in polar view. The spines are short with basal perforations at varying distances. Although the morphology of the pollen of species ofGraphistylis is very similar, multivariate analysis highlights the importance of quantitative traits in distinguishing species.

Highlights of the 2015 ERA-EDTA congress: chronic kidney disease, hypertension.

This paper reports the highlights in the field of chronic kidney disease (CKD) and hypertension of the last European Renal Association (ERA-EDTA) Congress (London, May 21-24, 2016). The items include an European survey on CKD epidemiology and a multicenter, open-label, randomized controlled trial on the effect of renal denervation for hypertension management. Furthermore, a polar view regarding ABPM for the diagnosis and the monitoring of hypertension in dialysis patients is presented.

Environmental Impacts of Industrial Pollution on Pollen Morphology of Eucalyptus globulus Labill. (Myrtaceae)

Study was aimed to investigate the effect of industrial air pollution on pollen morphology of Eucalyptus globulus Labill. , belonging to family Myrtaceae. Data revealed that there are differences in pollen morphological characteristics of E. globulus that grows in polluted industrial area in comparing with the pollen of that plant grows in healthy conditions (control area). Eucalyptus pollen grains are flattened triangular- obtuse- convex shape in polar view (the only view that is usually present). Aperture ( trizonocolpate- syncolpate), colpi fusing in each apocolpium to cut off an island of exine shaped like a triangle. Sculpture, psilate. The LM and SEM studies revealed that pollen grains of the control area showed normal size, shape and sculpture. While in case of polluted industrial one there is a shrinkage in size, thinning of exine, protrusion elements on the pollen surface, some attached particulate materials on the pollen surface ; that may be affected due to air pollution.

Evolution of Angiosperm Pollen. 3. Monocots1

Monocots, with ca. 65,000 species in 78 families and 12 orders as classified by the Angiosperm Phylogeny Group (Angiosperm Phylogeny Group III, 2009), have traditionally been known as a distinct assemblage from dicots within angiosperms and are now seen as a lineage that diverged from within the more basal of the angiosperm groupings. In this study, the third in a series analyzing pollen characters across the angiosperms, we illustrate the pollen morphological diversity of monocots and analyze 19 palynological and two ecological characters for 120 taxa in 71 families covering the 12 monocot orders and 16 taxa of nine orders in basal angiosperms. Pollen morphological data from previous works and our investigations were optimized onto a new maximum likelihood tree reconstructed from an existing DNA matrix of Chase et al. (2006) using Fitch parsimony, maximum likelihood, and hierarchical Bayesian analysis. From these analyses we infer evolutionary patterns in palynological characters, assess their systematic value, and investigate two aspects (pollination type and habitat moisture) of their ecological adaptation. The highest levels of pollen variation were shown to exist in the Alismatales and Commelinales, with lower levels seen in the Asparagales, Dasypogonales, and Zingiberales; the most variable characters across the phylogeny were found to be pollen outline in polar view, size, and tectum extent. We infer unambiguous plesiomorphic states for monocots and report significant transitions in character states at various levels within the monocot assemblage. Analyses of correlated evolution reconfirmed the hypothesis of an association between exine reduction (or complete loss) and habitat moisture and found significant correlations between various states of exine loss and habitat for hydrophytic–helophytic plants. The presence or absence of the exine itself was found to be more significantly correlated than individual structures, in terms of association with hydrophytic–helophytic plants. The most rapid rate of state changes in pollen characters, in the evolutionary history of monocots, is estimated to have occurred during the Albian-Turonian stage; our work may provide insights into the identification of enigmatic fossil pollen grains from this geological time.

Pollen morphology of Iranian &lt;i&gt;Dracocephalum&lt;/i&gt; L. (Lamiaceae) and its taxonomic significance

Pollen morphology of 11 Iranian Dracocephalum L. species was investigated using light and scanning electron microscopy to evaluate their taxonomic significance for the infrageneric classification of the genus. Pollen grains of all examined taxa were isopolar, hexacolpate, circular in polar view and spheroidal to prolate in equatorial view (P/E = 1.0?2.0). The smallest pollen grains were observed in D. aucheri (P = 29.7 ?m, E = 22.6 ?m), while the largest pollen was found in D. lindbergii (P = 45.1 ?m, E = 33.7 ?m). The highest and lowest apocolpium index (AI) were measured in D. aucheri (AI = 0.27) and D. surmandinum (AI = 0.08), respectively. Colpus membrane was egranulate in all examined species except for D. multicaule and D. ghahremanii. The main exine ornamentation type was characterized as bireticulate including five different subtypes. The results revealed that the exine ornamentation is a diagnostic character useful for the classification of Dracocephalum.Bangladesh J. Plant Taxon. 22(2): 99-110, 2015 (December)

Nectar and Pollen Production and Insect Visitation on Ornamentals from the Genus Hosta Tratt. (Asparagaceae)

Abstract Properly arranged ornamental gardens in both urban and agricultural landscapes can be of a benefit to bees. In this study, we observed the flowering phenology, nectar, and pollen production of the ornamental Hosta species and varieties (H. sieboldiana Engler, H. capitata Nakai, H. crispula Maekawa, H. fluctuans Maekawa, syn. H. sieboldiana var. fluctuans hort., H. undulata var. univittata Miquel (Hylander), syn. H. univittata). Our experiment was conducted in the 2012 - 2014 time period, at the UMCS Botanical Garden in Lublin, Poland (51° 14’ N, 21° 34’ E). The total sugar yield varied almost 5-fold among Hosta ornamentals; the lowest amount was calculated for H. fluctuans (2.31 g per 10 m2) and the highest for H. capitata (11.80 g per 10 m2). The average pollen yield was from 0.24 g per 10 m2 (H. undulata var. univittata) to 9.53 g per 10 m2 (H. capitata). Pollen grains were bilaterally symmetrical, and large-sized. In polar view, they were prolatum (shape index 1.33 - 1.61), while in equatorial view, oblatum (shape index 0.5 - 0.7). Hosta species can complete the summer pasture mainly for bumblebees. In four of the five Hosta representatives, bumblebees accounted for 60 - 70% of the total visits. The honeybee predominated only on the flowers of H. capitata (54 - 71%). Solitary bees were rarely observed (3 - 9% of visits). The phenotypic traits of Hosta flowers (the accumulation of nectar in the deep and narrow perianth tube) reduced the access to nectar reward and restricted an array of insect visitors.

Pollen morphology of Poaceae (Poales) in the Azores, Portugal

The objective of this study was to expand knowledge on the Poaceae and morphologically describe pollen grains of species occurring in the Azores Archipelago, Portugal. Pollen grains from each species under study were subjected to standard acetolysis, mounting of at least three permanent slides of each species for observations and measurement of pollen grains under light and scanning electron microscope. With regard to pollen morphology, all pollen grains were arranged as monads, with a single pore-type aperture – monoporate, featuring annulus and operculum; and outline in polar view circular, sub-circular and ovalate. Most species featured pollen size small, except for Agrostis stolonifera with pollen size very small, Brachypodium sylvaticum with pollen size medium, Zea mays with pollen size large. Species endemic to the archipelago show ornamentation pattern ranging between areolate-microechinate, microechinate, microrugulate-microechinate and verrucate-microechinate, most of which feature exine surface areolate-microechinate. Among endemic species, Rostraria azorica stood out for its oblate-spheroidal shape, whereas most species showed prolate-spheroidal shape.