Family Of Trees Research Articles

Infinite families of trees with equal spectral radius

In this note we show that for each positive integer a⩾2 there exist infinitely many trees whose spectral radius is equal to 2a. Such trees are obtained by replacing the central edge of the double star S(a,2a−2) with suitable bidegreed caterpillars.

Can daily consumption of enriched fatty acids diet be effective in improving metabolic syndrome? An attractive paradox for walnut kernel.

Imagine consuming a daily diet rich in fatty acids to help treat diseases such as hypertension and obesity. This concept presents an attractive paradox. In particular, consuming walnut kernels is beneficial for treating diseases associated with metabolic syndrome (MetS), including type 2 diabetes, cardiovascular disease, dyslipidemia, and obesity. Different parts of the Juglans regia tree (family Juglandaceae), including its leaves, green husks, bark, and septum, have shown promising effects on pathological conditions related to MetS. The therapeutic advantages of consuming walnut kernels for MetS can be attributed to the presence of polyunsaturated fatty acids and polyphenolic compounds such as juglone and ellagic acid. Diets enriched with walnut kernel have a positive impact on MetS complications by reducing diastolic blood pressure, improving blood lipid profiles, lowering fasting blood sugar levels, and increasing insulin sensitivity. The potential cellular mechanisms responsible for these benefits involve activating the cholesterol hemostasis pathway by inhibiting sterol regulatory element-binding proteins (SREBPs), proprotein convertase subtilisin/kexin type 9 (PCSK9), and cholesteryl ester transfer protein (CETP). Furthermore, other by-products of walnuts, such as leaves and green husks, have also demonstrated effectiveness in managing MetS. These findings highlight the potential of incorporating walnut-based products into our diets as a natural approach to combating MetS and its complications.

Variation of floristic diversity, community composition, endemism, and conservation status of tree species in tropical rainforests of Sri Lanka across a wide altitudinal gradient

Tropical rainforests in Sri Lanka are biodiversity hotspots, which are sensitive to anthropogenic disturbance and long-term climate change. We assessed the diversity, endemism and conservation status of these rainforests across a wide altitudinal range (100–2200 m above sea level) via a complete census of all trees having ≥ 10 cm diameter at breast height in ten one-hectare permanent sampling plots. The numbers of tree families, genera and species and community-scale tree diversity decreased with increasing altitude. Tree diversity, species richness and total basal area per ha across the altitudinal range were positively associated with long-term means of maximum temperature, annual rainfall and solar irradiance. Percentage of endangered species increased with increasing altitude and was positively associated with cumulative maximum soil water deficit, day-night temperature difference and high anthropogenic disturbance. Percentage of endemic species was greater in the lowland rainforests than in high-altitude montane forests. Nearly 85% of the species were recorded in three or less plots, which indicated substantial altitudinal differentiation in their distributions. Less than 10 individuals were recorded in 41% of the endemic species and 45% of the native species, which underlined the need for urgent conservation efforts across the whole altitudinal range.

Role of hydrogen peroxide receptors in endocarp browning of postharvest longan fruit

AbstractLongan (Dimocarpus longan) is an important subtropical evergreen fruit tree (family Sapindaceae) in southern China and exhibits a high commercial and nutritional value. Endocarp browning of longan fruit once harvested considerably reduces the commercial value. The excessive accumulation of reactive oxygen species (ROS) can induce the rapid endocarp browning of longan fruit during storage, but the ROS‐mediated mechanism remains relatively unclear. In this investigation, a hydrogen peroxide scavenger, 1,3‐dimethylthiourea (DMTU), was used to treat longan fruit to elucidate the physiological and molecular bases of the ROS‐mediated endocarp browning of longan fruit. Application of 5 mM DMTU significantly delayed endocarp browning, inhibited respiration rate, suppressed the accumulations of H2O2 and malondialdehyde (MDA), and activated the antioxidant system of longan fruit during storage, such as 3.8 of the DMTU‐treated fruit versus 1.6 of non‐DMTU‐treated fruit of the browning index, 398 versus 346 μg kg−1 S−2 of the respiration rate, and 47.5 versus 37.8 nmol g−1 of the MDA content after 6 days of storage. Furthermore, the DMTU treatment significantly affected the expression levels of the H2O2 receptors and hydrogen peroxide‐induced Ca2+ increases (HPCA)‐LIKEs (HPCALs). Additionally, the regulatory network comprising transcription factors controlling the HPCAL expression in longan was constructed. The major transcription factors, including GATA1, GATA28, TCP20, and AGL20, may contribute to the ROS‐mediated endocarp browning of longan fruit during storage by regulating the HPCAL expression levels. This study could provide new insights into the involvement of the HPCALs in the ROS‐mediated endocarp browning of longan fruit during storage.

Antimicrobial and antibiofilm activities of Inga cylindrica trypsin inhibitor.

Inga cylindrica, a tropical fruit tree of the Fabaceae family (subfamily Mimosoideae), is native to South America. The seeds from this family are an essential source of trypsin inhibitors, which display promising bioactivity for increasing host defense against pathogens. The aim of the present study was to characterize the antimicrobial and antibiofilm activities of the trypsin inhibitor extracted from I. cylindrica seeds, ICTI. ICTI demonstrated antifungal activity with a minimum inhibitory concentration (MIC) of 32.11 μmol.L-1, and a minimum fungicidal concentration (MFC) of 32.1 μmol.L-1, against Cryptococcus gattii, Candida albicans, Candida glabrata and Candida guilliermondii. Combining ICTI with Amphotericin B had a significant synergistic effect, reducing the concentration of the antibiotic by 75% for C. albicans and 94% for C. gatti. The significant increase (16 x) in activity observed with ergosterol (1.01 mol.L-1) for C. albicans and C. gatti, and the lack of activity against bacterial strains, suggests that ICTI interferes with the integrity of the fungal cell membrane. Treatment with ICTI at 10 x MIC resulted in a 51% reduction in biofilm formation and a 56% decrease in mature biofilm colonies for C. albicans. Finally, ICTI displayed no toxicity in the in vivo Galleria mellonella model. Given its antifungal and antibiofilm properties, ICTI could be a promising candidate for the development of new antimicrobial drug prototypes.

Diversity of bee tree (sambit) for Apis dorsata conservation in Membalong, Belitung Regency, Indonesia

The land transformation of forests to monoculture threatened the existence of biodiversity in Belitung, including the bee trees (local name: sambit) for Apis dorsata nesting. Bee farmers are having difficulty finding numerous kinds of bee trees. The objectives of this study were (1) to identify the species of bee trees, (2) to characterize the nesting branches of the bee tree, and (3) to identify the ecosystem of the bee trees in three villages in Membalong, Belitung Regency. Data were collected using: (1) interviewing bee farmers, (2) measurements of nesting branches, and (3) exploring the bee tree ecosystems. We discovered 22 species (13 families) of bee trees, with Myrtaceae was the most frequent. Syzygium cymosum (local name: mengkeling) was a common nesting tree of A. dorsata. The characteristics of bee trees were: height of the nesting branch: 7.85 ± 3.80 m above the ground, length of the branch: 2.74 ± 1.43 m, and the incline of the branch: 20.20° ± 2.57°. We found bee trees in terrestrial ecosystems (primary and secondary heath forests) and wetlands (swamps and mangroves). The last ecosystem was a new finding. We suggest local communities cultivate the native plants and reduce the area of forest land used.

Some Existence Theorems on Star Factors

The [Formula: see text]-factor and [Formula: see text]-factor of a graph are a spanning subgraph whose each component is an element of [Formula: see text] and [Formula: see text], respectively, where [Formula: see text] is a special family of trees. In this paper, we obtain a sufficient condition in terms of tight toughness, isolated toughness and binding number bounds to guarantee the existence of a [Formula: see text]-factor and [Formula: see text]-factor for any graph.

Quadratic Starlike Trees

We introduce the notion of a quadratic graph, which is a graph whose eigenvalues are integral or quadratic algebraic integral, and we determine nine infinite families of quadratic starlike trees, which are just all the quadratic starlike trees including integral starlike trees. Thus, the quadratic starlike trees are completely characterized. The expressions for characteristic polynomials of quadratic starlike trees are also given.

Differential effects of tree species identity on rhizospheric bacterial and fungal community richness and composition across multiple trace element-contaminated sites

Soil microbial communities play a key role in plant nutrition and stress tolerance. This is particularly true in sites contaminated by trace metals, which often have low fertility and stressful conditions for woody plants in particular. However, we have limited knowledge of the abiotic and biotic factors affecting the richness and composition of microbial communities inhabiting the rhizosphere of plants in contaminated sites. Using high-throughput amplicon sequencing, we studied the rhizospheric bacterial and fungal community structures of 14 woody plant families planted in three contrasting sites contaminated by metals (Pb, Cd, Zn, Mn, Fe, S). The rhizospheric bacterial communities in the given sites showed no significant difference between the various woody species but did differ significantly between sites. The Proteobacteria phylum was dominant, accounting for over 25 % of the overall relative abundance, followed by Actinobacteria, Bacteroidetes and Gemmatimonadetes. Site was also the main driver of fungal community composition, yet unlike bacteria, tree species identity significantly affected fungal communities. The Betulaceae, Salicaceae and Fagaceae families had a high proportion of Basidiomycota, particularly ectomycorrhizal fungi, and the lowest diversity and richness. The other tree families and the unplanted soil harboured a greater abundance of Ascomycota and Mucoromycota. Consequently, for both bacteria and fungi, the site effect significantly impacted their community richness and composition, while the influence of plants on the richness and composition of rhizospheric microbial communities stayed consistent across sites and was dependent on the microbial kingdom. Finally, we highlighted the importance of considering this contrasting response of plant rhizospheric microbial communities in relation to their host identity, particularly to improve assisted revegetation efforts at contaminated sites.

Оценка гибридных сеянцев яблони по основным хозяйственно-биологическим признакам в Оренбургской области

Abstract. The aim is to evaluate hybrid apple seedlings according to the main economic and biological characteristics in the conditions of the Orenburg region. Methods. The studies were carried out from 2002 to 2022 in the Orenburg branch of the Federal State Budget Scientific Institution of the Federal Scientific Center for Horticulture. The objects of research were 10 hybrid families of apple trees selected by the Federal State Budget Scientific Institution of the Federal Scientific Center for Horticulture. The main observations and records on the main economic and biological characteristics were carried out according to the methodology “Program and methodology for the selection of fruit, berry and nut crops”, “Program and methodology for the study of variety of fruit, berry and nut crops”, statistical processing of experimental data was carried out by the method of two-factor analysis of variance, where A is the variety, B is the year. The scientific novelty lies in the fact that as a result of the conducted research, promising hybrid forms with a complex of economically valuable traits, with a high potential for productivity and large-fruiting in the conditions of the Orenburg region have been identified. Results. The genetic collection of the Orenburg branch of the Federal State Budgetary Scientific Institution of the Federal Scientific Center for Horticulture serves as a fundamental basis for breeding work, which makes it possible to intensify the creation of adaptive, highly productive apple varieties. It has been established that the majority of hybrid apple seedlings have high winter hardiness. Weak freezing (0.2–0.5 points) characterizes hybrids of crossbreeding combinations, such as BratChud × Simvol, Kovrovoe × Anis Sverdlovskiy. Phytosanitary monitoring carried out on the site of hybrid apple seedlings showed that over the years of the study, weather conditions did not allow the development of diseases in the apple tree. On average, fruits in the offspring were 1-1, 1-5, 1-6, 1-7, 1-8, 1-9, 1-10 (140.0 ... 150.0 g). The greatest productivity was formed by hybrids of combinations of crossing BratChud × Simvol (24.6 kg/tree), Orskoe × Prizemlennoe (24.0 kg/tree) and Arkaim × Podarok Orenburzh’yu (24.2 kg/tree).

A lattice structure for ancestral configurations arising from the relationship between gene trees and species trees

To a given gene tree topology G and species tree topology S with leaves labeled bijectively from a fixed set X, one can associate a set of ancestral configurations, each of which encodes a set of gene lineages that can be found at a given node of the species tree. We introduce a lattice structure on ancestral configurations, studying the directed graphs that provide graphical representations of lattices of ancestral configurations. For a matching gene tree topology and species tree topology G=S, we present a method for defining the digraph of ancestral configurations from the tree topology by using iterated cartesian products of graphs. We show that a specific set of paths on the digraph of ancestral configurations is in bijection with the set of labeled histories — a well-known phylogenetic object that enumerates possible temporal orderings of the coalescences of a tree. For each of a series of tree families, we obtain closed-form expressions for the number of labeled histories by using this bijection to count paths on associated digraphs. Finally, we prove that our lattice construction extends to nonmatching tree pairs, and we use it to characterize pairs (G,S) having the maximal number of ancestral configurations for a fixed G. We discuss how the construction provides new methods for performing enumerations of combinatorial aspects of gene and species trees.

Analyzing Indo-European Language Similarities Using Document Vectors

The evaluation of similarities between natural languages often relies on prior knowledge of the languages being studied. We describe three methods for building phylogenetic trees and clustering languages without the use of language-specific information. The input to our methods is a set of document vectors trained on a corpus of parallel translations of the Bible into 22 Indo-European languages, representing 4 language families: Indo-Iranian, Slavic, Germanic, and Romance. This text corpus consists of a set of 532,092 Bible verses, with 24,186 identical verses translated into each language. The methods are (A) hierarchical clustering using distance between language vector centroids, (B) hierarchical clustering using a network-derived distance measure, and (C) Deep Embedded Clustering (DEC) of language vectors. We evaluate our methods using a ground-truth tree and language families derived from said tree. All three achieve clustering F-scores above 0.9 on the Indo-Iranian and Slavic families; most confusion is between the Germanic and Romance families. The mean F-scores across all families are 0.864 (centroid clustering), 0.953 (network partitioning), and 0.763 (DEC). This shows that document vectors can be used to capture and compare linguistic features of multilingual texts, and thus could help extend language similarity and other translation studies research.

The growth rate and genetic variability of Scots pine (Pinus sylvestris L.) half-sibs in test crops of Northern Kazakhstan

Scots pine (Pinus sylvestris L.) is a valuable tree species, playing an important role in maintaining the ecological and economic balance not only in Kazakhstan, but also in many countries around the world. The purpose of this study was to assess the growth rate and to identify the genotypes of the half-sib progeny of Scotch pine plus trees in order to further obtain high-quality seeds with valuable genetic traits. A molecular genetic analysis was carried out using six microsatellite and 20 isoenzyme loci on 15 Scots pine half-sib families, represented by two samples of seeds collected in the subsequent harvesting periods (planted in 1986 and 1987), that evaluated the taxonomic characteristics such as tree height and trunk diameter (DBH, measured at 1.3 meters). Families with the highest growth rate in both samples were selected as candidates for the elite group. During the SSR analysis, a decrease in the level of expected heterozygosity (0.2377-0.5362 with an average value of 0.4593) was observed in P. sylvestris L. half-sibs compared to the sample of maternal plus trees (0.5444), with similar results to that of the “founder effect”. At the same time, the level of observed heterozygosity remained sufficiently high (0.3333-0.7037 with an average value of 0.4980 and 0.4556, respectively). During the isoenzyme analysis, the level of genetic variability either decreased or was similar to that of the maternal trees. Rare and unique alleles were found in seed samples of the analysed tree families. In general, this research showed that a comprehensive evaluation combining both traditional breeding methods (genetic assessment of progeny in the course of growth) and molecular genetic analysis is required for the selection of elite trees.

Generalizing event studies using synthetic controls: An application to the Dollar Tree–Family Dollar acquisition

Event studies, which have significantly advanced mergers and acquisitions (M&A) research, obtain excess returns based on a theory linking a firm's shareholder returns to those of the market. For outcomes lacking such a theory, we propose an empirical approach using a synthetic control method with machine learning to link outcomes for the acquirer or target to those for a group of comparison firms. We discuss the method's assumptions, its close parallel to event studies, and its difference in weighting comparison firms (based on data versus derived from theory). We provide an illustration of Dollar Tree's acquisition of Family Dollar, by analyzing shareholder returns (to demonstrate consistent results with an event study), realized cost and sales synergies, and customer sentiment (derived from more than 52 million Twitter messages). We highlight this method's potential—for M&A and other areas of strategy research—to open up new lines of inquiry.

Characterization and Application in Natural Rubber of Leucaena Leaf and Its Extracted Products.

Leucaena is a fast-growing tree in the legume family. Its leaf contains a significant amount of protein and is thus widely used as fodder for cattle. To broaden its application in the rubber field, the effects of Leucaena leaf powder and its extracted products on the cure characteristics and mechanical properties of natural rubber were investigated. The extraction of Leucaena leaf was carried out by using a proteolytic enzyme at 60 °C. The digested protein was separated from the residue by centrifugation. Both digested protein and residue were then dried and ground into powder, namely digested protein powder and residual powder, respectively, before being characterized by Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis, X-ray diffraction, particle size determination, and protein analysis. After being added to natural rubber at 3 parts per hundred rubber, they significantly reduced both the scorch time and the optimum cure time of the rubber compounds, probably due to the presence of nitrogen-containing substances, without a significant sacrifice of the mechanical properties. For instance, the optimum cure time decreased by approximately 25.5, 35.4, and 54.9% for Leucaena leaf powder, residual powder, and digested protein powder, respectively. Thus, they can be used as green and sustainable fillers with a cure-activation effect in rubber compounding.

Extremal graphs for average sizes of maximal matchings

A matching of a graph G is called a maximal matching if it is not properly contained in any matching of G. The average size of a maximal matching ofG, avm(G), is the average value taken over the sizes of all maximal matchings of G. Which graphs G have the maximum or minimum value of avm(G) when G is restricted to a particular family? We answer this question, with a full characterization of the extremal graphs, in the families of trees, (connected) unicyclic graphs, trees with a fixed diameter d≤5, and 2-regular graphs.

Tree species diversity adapted to Pinus merkusii forests in Gunung Ciremai National Park, West Java, Indonesia

Abstract. Supartono T, Adhya I, Kosasih D, Wildani W. 2023. Tree species diversity adapted to Pinus merkusii forests in Gunung Ciremai National Park, West Java, Indonesia. Biodiversitas 24: 4314-4323. One of the challenges faced in rehabilitating pine forests in conservation areas is the limited information on plant species capable of adapting to these ecosystems. This study aimed to analyze the diversity of tree species that grow and adapt to pine forests and the relationship of natural forests with the vegetation characteristics of pine forests. The research was conducted in pine forests bordering natural forests and far from natural forests using the sample plot method. The study recorded 44 species from 27 families of seedlings, 46 species from 21 families of saplings, 25 species from 18 families of poles, and 24 species from 17 families of trees. Accumulation of species from all growth stages recorded 83 species (76 local species and 7 cultivated species) from 39 families. Based on the species accumulation curve, pine forests adjacent to natural forests have more species than those far from natural forests. Individual and family density in pine forests adjacent to natural forests were also higher than the density of these two variables in pine forests far from natural forests. Furthermore, both the pine forest adjacent to the natural forest and that far from the natural forest, each has its own species peculiarities. The results indicate that the existence of natural forests has an important role as a source of biodiversity for the surrounding ecosystem. As an implication of this study, species that can grow to the level of poles and trees can be recommended as rehabilitation plants in the Pinus merkusii Jungh. & de Vriese forests in Gunung Ciremai National Park, Indonesia because pine is not a local species and the allelopathy it releases can reduce plant diversity.

Evaluation of Mechanical Properties of Goat Leather Tanned using Acacia xanthophloea

Acacia xanthophloea is a tree in the Fabaceae family with wide distribution mainly around Laikipia in Central Kenya and major parts of the Rift Valley town of Naivasha, Kenya. A number of trees under the Fabaceae family are renowned as sources of vegetable tannins for leather processing. Despite recent advances in research, locally available vegetable tanning materials have not been widely exploited in Kenya for commercial tanning purposes. This study aimed to evaluate the mechanical properties of goat leather tanned with crude extracts of Acacia xanthophloea from Naivasha, Kenya. Crude extracts of Acacia xanthophloea combined with pre-tanning and tanning procedures were used to produce leather. The commercial mimosa was used as a control. The leather tanned with crude extracts of Acacia xanthophloea had a thickness of 0.81 ± 0.11 mm, tearing strength of 37.87 ± 2.09 N, tensile strength of 27.50 ± 7.51 N/mm2, percentage elongation of 18.00 ± 6.67, grain crack of 6.19 ± 0.20 mm and grain burst of 7.10 ± 0.27 mm. The crude extracts of Acacia xanthophloea confer good tanning and give the leather a reddish tinge, whereas some mechanical properties attenuated, compare favourably with the control (mimosa). Acacia xanthophloea which is abundantly available in Kenya with scarce use can potentially be cultivated and refined as a commercial source of tannins.

Cutoff on Trees is Rare

We study the simple random walk on trees and give estimates on the mixing and relaxation times. Relying on a seminal result by Basu, Hermon and Peres characterizing cutoff on trees, we give geometric criteria that are easy to verify and allow to determine whether the cutoff phenomenon occurs. We provide a general characterization of families of trees with cutoff, and show how our criteria can be used to prove the absence of cutoff for several classes of trees, including spherically symmetric trees, Galton–Watson trees of a fixed height, and sequences of random trees converging to the Brownian continuum random tree.

Graphs Isomorphisms Under Edge-Replacements and the Family of Amoebas

This paper offers a systematic study of a family of graphs called amoebas. Amoebas recently emerged from the study of forced patterns in $2$-colorings of the edges of the complete graph in the context of Ramsey-Turan theory and played an important role in extremal zero-sum problems. Amoebas are graphs %with a unique behavior with regards to defined by means of the following operation: Let $G$ be a graph and let $e\in E(G)$ and $e'\in E(\overline{G})$. If the graph $G'=G-e+e'$ is isomorphic to $G$, we say $G'$ is obtained from $G$ by performing a feasible edge-replacement. We call $G$ a local amoeba if, for any two copies $G_1$, $G_2$ of $G$ on the same vertex set, $G_1$ can be transformed into $G_2$ by a chain of feasible edge-replacements. On the other hand, $G$ is called global amoeba if there is an integer $t_0 \ge 0$ such that $G \cup tK_1$ is a local amoeba for all $t \ge t_0$. To model the dynamics of the feasible edge-replacements of $G$, we define a group $\rm{Fer}(G)$ that satisfies that $G$ is a local amoeba if and only if $\rm{Fer}(G) \cong S_n$, where $n$ is the order of $G$. Via this algebraic setting, a deeper understanding of the structure of amoebas and their intrinsic properties comes into light. Moreover, we present different constructions that prove the richness of these graph families showing, among other things, that any connected graph can be a connected component of a global amoeba, that global amoebas can be very dense and that they can have, in proportion to their order, large clique and chromatic numbers. Also, a family of global amoeba trees with a Fibonacci-like structure and with arbitrary large maximum degree is constructed.