Nectaries and male-biased nectar production in protandrous flowers of a perennial umbellifer Angelica sylvestris L. (Apiaceae)

Nectar is the most common floral pollinator reward. In dichogamous species, floral nectar production rates can differ between sexual phases. We studied the structure of nectaries located on the stylopodium and nectar production in protandrous umbellifer Angelica sylvestris. Our study species produced nectar in both floral sexual phases. Nectar sugar concentration was low (on average 22 ± 11 %, mean ± SD) and the nectar hexose rich and composed of sucrose, glucose, fructose and a small amount of amino acids, including β-alanine, a non-protein amino acid. Although nectar composition and sugar concentration varied little between floral sexual phases, nectar production showed a threefold reduction during the stigma receptive period. This is in contrast to other studies of Apiaceae that have reported female-biased nectar production, but in the direction predicted by plant sexual selection theory, suggesting that in pollen-unlimited species, floral rewards mainly enhance male reproductive success. The structure of the nectary was similar at the two sexual stages investigated, and composed of a secretory epidermis and several layers of nectariferous and subsecretory parenchyma. The nectary cells were small, had large nuclei, numerous small vacuoles and dense, intensely staining cytoplasm with abundant endoplasmic reticulum, mitochondria and secretory vesicles. They contained abundant resin-like material that may potentially act as defence against microbes. Starch was rarely observed in the nectary cells, occurring predominantly at the female stage and mainly in guard and parenchyma cells in close proximity to stomata, and in subsecretory parenchyma. The main route of nectar release in A. sylvestris seems to be via modified stomata

The Power of Dynamic Distance Oracles: Efficient Dynamic Algorithms for the Steiner Tree

In this paper we study the Steiner tree problem over a dynamic set of terminals. We consider the model where we are given an $n$-vertex graph $G=(V,E,w)$ with positive real edge weights, and our goal is to maintain a tree which is a good approximation of the minimum Steiner tree spanning a terminal set $S \subseteq V$, which changes over time. The changes applied to the terminal set are either terminal additions (incremental scenario), terminal removals (decremental scenario), or both (fully dynamic scenario). Our task here is twofold. We want to support updates in sublinear $o(n)$ time, and keep the approximation factor of the algorithm as small as possible. We show that we can maintain a $(6+\varepsilon)$-approximate Steiner tree of a general graph in $\tilde{O}(\sqrt{n} \log D)$ time per terminal addition or removal. Here, $D$ denotes the stretch of the metric induced by $G$. For planar graphs we achieve the same running time and the approximation ratio of $(2+\varepsilon)$. Moreover, we show faster algorithms for incremental and decremental scenarios. Finally, we show that if we allow higher approximation ratio, even more efficient algorithms are possible. In particular we show a polylogarithmic time $(4+\varepsilon)$-approximate algorithm for planar graphs. One of the main building blocks of our algorithms are dynamic distance oracles for vertex-labeled graphs, which are of independent interest. We also improve and use the online algorithms for the Steiner tree problem.Comment: Full version of the paper accepted to STOC'1

An Exponential Lower Bound for Cut Sparsifiers in Planar Graphs

Given an edge-weighted graph G with a set Q of k terminals, a mimicking network is a graph with the same set of terminals that exactly preserves the sizes of minimum cuts between any partition of the terminals. A natural question in the area of graph compression is to provide as small mimicking networks as possible for input graph G being either an arbitrary graph or coming from a specific graph class. In this note we show an exponential lower bound for cut mimicking networks in planar graphs: there are edge-weighted planar graphs with k terminals that require 2^(k-2) edges in any mimicking network. This nearly matches an upper bound of O(k * 2^(2k)) of Krauthgamer and Rika [SODA 2013, arXiv:1702.05951] and is in sharp contrast with the O(k^2) upper bound under the assumption that all terminals lie on a single face [Goranci, Henzinger, Peng, arXiv:1702.01136]. As a side result we show a hard instance for the double-exponential upper bounds given by Hagerup, Katajainen, Nishimura, and Ragde [JCSS 1998], Khan and Raghavendra [IPL 2014], and Chambers and Eppstein [JGAA 2013]

Morphological and genetic diversity of European cranberry (Vaccinium oxycoccos L., Ericaceae) clones in Lithuanian reserves

The wild-harvested fruit of Vaccinium oxycoccos (European cranberry) is used medicinally in many European and North American countries; the plant, however, is seldom cultivated. In order to optimize the collection strategy and improve the horticulturally important characters of V. oxycoccos clones, comprehensive investigations of the species are necessary. In the present study we investigated the phenological, morphological and genetic diversity of 29 clones originating from two wild populations growing in two strictly protected Lithuanian reserves, Čepkeliai and Žuvintas. During an ex situ collection at Kaunas Botanical Garden, we observed great phenological variation between the collected V. oxycoccos clones. The following morphological traits most clearly distinguished our study clones: leaf size, berry shape, berry size and fruit colour at full maturity. The genetic variation of V. oxycoccos clones from the two populations was assessed using RAPD and SSR. RAPD analysis conducted with 9 primers resulted in 146 polymorphic loci for the total sample, and SSR analysis with 5 primers revealed 29 alleles for the total sample. A greater degree of polymorphism was demonstrated for the Čepkeliai population than for the Žuvintas population. The study allowed the selection of several clones having promising morphological traits for further testing in the field

COMPARATIVE ASSESSMENT OF Al-Si ALLOY GASSING DEGREE WITH THE APPLICATION OF THE ‘FIRST BUBBLE’ AND ‘SOLIDIFICATION UNDER DECREASED PRESSURE’ METHODS

All aluminum alloys in a liquid state are characterised by easy oxidation and absorption of hydrogen from the surroundings (which are the main reasons for casting defects). The amount of hydrogen adsorbed by a liquid alloy depends mainly on temperature and melting time. The performed investigations were aimed at comparing two known methods of measuring a metal gassing degree; the first bubble method and sample solidification under decreased pressure. Liquid metal melting and holding processes were performed under different conditions that caused variability of its gassing degree, resulting in a variability of purity and quality of the liquid metal. The investigations were carried out with using the hypoeutectic aluminum-silica AK7 alloy

Umbellifers as potential keystone species in restoration projects

We studied visitation rates to four common European umbellifers: Angelica sylvestris, Anthriscus sylvestris, Daucus carota, and Heracleum sphondylium. Our observations and literature data confi rm that a single plant species from the family Apiaceae may be visited by over a hundred insect taxa from taxonomically diverse groups. Here we suggest that in the light of pollination shortage faced by many endangered plant species, co-planting of relevant native Apiaceae plants, especially in Europe, should be taken into consideration in many restoration projects to provide, via umbelliferean magnet species, appropriate pollination service for focus plant taxa

Effects of process parameters on structure and properties of melt-blown poly(lactic acid) nonwovens for skin regeneration

Skin regeneration requires a three-dimensional (3D) scaffold for cell adhesion, growth and proliferation. A type of the scaffold offering a 3D structure is a nonwoven material produced via a melt-blown technique. Process parameters of this technique can be adapted to improve the cellular response. Polylactic acid (PLA) was used to produce a nonwoven scaffold by a melt-blown technique. The key process parameters, i.e., the head and air temperature, were changed in the range from 180–270 °C to obtain eight different materials (MB1–MB8). The relationships between the process parameters, morphology, porosity, thermal properties and the cellular response were explored in this study. The mean fiber diameters ranged from 3 to 120 µm. The average material roughness values were between 47 and 160 µm, whereas the pore diameters ranged from 5 to 400 µm. The calorimetry thermograms revealed a correlation between the temperature parameters and crystallization. The response of keratinocytes and macrophages exhibited a higher cell viability on thicker fibers. The cell-scaffold interaction was observed via SEM after 7 days. This result proved that the features of melt-blown nonwoven scaffolds depended on the processing parameters, such as head temperature and air temperature. Thanks to examinations, the most suitable scaffolds for skin tissue regeneration were selected

METALLOSTATIC PRESSURE FUNCTION IN THE QUALITY OF Al-Si ALLOY CASTINGS MADE IN SAND MOULDS

The paper presents results of the studies regarding influence of metallostatic pressure of AlSi7Mg alloy on surface roughness of castings prepared in sand moulds as well as on alloy’s density. Castings in a cylindrical shape with a diameter of 15.0; 25.0 or 3.5 mm and height of 700 mm that were cast in a vertical orientation are investigated. The melted alloy was poured into moulds in two ways: bottom up, and top down. Higher pressure and larger diameter of castings favors increaseof surface roughness. In the analyzed range of height of a metal column, density increases linearly: for instance, in case of castings with diameter of ø25 mm, the density increases from ρ = 2.60 g/cm3 to ρ = 2.68 g/cm3, what is about 0.10 g/cm3. In the roller with larger diameter, the density is slightly smaller, however the range of changes along the longer axis is similar to that in the cylinder with diameter of ø25 mm. Additional, ultrasonic studies were performed, which prove that with small changes of the alloy density, velocity of a longitudinal wave changes only slightly. Thus, it is difficult to control small variations (Δρ < 0,10 g/cm3) in density of AlSi7Mg alloy with ultrasonic technique

Rola edukacji zdrowotnej u chorych z niewydolnością serca

According to European Society of Cardiology guidelines, the goal of heart failure (HF) management is to provide an effective system of care through the whole patient’s journey including hospital and ambulatory pathway. Strategies based on patients’ education, psychosocial support and monitoring should be considered as a fundamental part of multidisciplinary disease management programs and may lead to a reduction in mortality and morbidity and improvement in the quality of life. In this article, we focus on patient’s education strategies by describing different models: “one-to-one” strategies, multidisciplinary care management programs, activation of the family members, pharmaceutical care, and end-stage HF advance care planning. Furthermore, we explain the problem of health literacy among HF patients and describe actionable advice on how medical professionals can effectively improve patients’ comprehension and knowledge on disease management and the ability for self-care. Lastly, we review the latest evidence on outcomes obtained by HF education.Według wytycznych Europejskiego Towarzystwa Kardiologicznego głównym celem postępowania u chorych z niewydolnością serca jest tworzenie efektywnych systemów opieki na każdym etapie ścieżki pacjenta, włączając w to opiekę szpitalną i ambulatoryjną. Strategie postępowania oparte na edukacji, wsparciu psychologicznym i monitoringu powinny stanowić fundamentalny element wielospecjalistycznych zespołów zajmujących się prowadzeniem chorych z niewydolnością serca (HF). W niniejszym artykule autorzy skupiają się na edukacji pacjentów, przedstawiając różne jej modele: edukację w modelu rozmowy bezpośredniej, wielospecjalistyczne programy opieki, aktywację członków rodziny chorego, edukację z zaangażowaniem farmaceutów, a także edukację związaną z planowaniem opieki terminalnej. Ponadto opisano zagadnienie alfabetyzmu zdrowotnego wśród chorych z HF oraz zaproponowano możliwe działania, dzięki którym pracownicy ochrony zdrowia mogą poprawić zrozumienie informacji na temat choroby oraz zdolność do samoopieki wśród pacjentów. Autorzy przeprowadzili również przegląd dostępnych danych z piśmiennictwa na temat skuteczności edukacji w HF