Distance-based clustering methods categorize samples by optimizing a global criterion, finding ellipsoid clusters with roughly equal sizes. In contrast, density-based clustering techniques form clusters with arbitrary shapes and sizes by optimizing a local criterion. Most of these methods have several hyper-parameters, and their performance is highly dependent on the hyper-parameter setup. Recently, a Gaussian Density Distance (GDD) approach was proposed to optimize local criteria in terms of distance and density properties of samples. GDD can find clusters with different shapes and sizes without any free parameters. However, it may fail to discover the appropriate clusters due to the interfering of clustered samples in estimating the density and distance properties of remaining unclustered samples. Here, we introduce Adaptive GDD (AGDD), which eliminates the inappropriate effect of clustered samples by adaptively updating the parameters during clustering. It is stable and can identify clusters with various shapes, sizes, and densities without adding extra parameters. The distance metrics calculating the dissimilarity between samples can affect the clustering performance. The effect of different distance measurements is also analyzed on the method. The experimental results conducted on several well-known datasets show the effectiveness of the proposed AGDD method compared to the other well-known clustering methods.

Let G be a connected graph, and let D[G] denote the double graph of G. In this paper, we first derive closed-form formulas for some distance based topological indices for D[G] in terms of G. Finally, these formulas are applied for several special kinds of graphs, such as, the complete graph, the path and the cycle.

Let G and H be connected graphs. The tensor product G + H is a graph with vertex set V(G+H) = V (G) x V(H) and edge set E(G + H) ={(a , b)(x , y)| ax Î E(G) & by Î  (H)}. The graph H is called the strongly triangular if for every vertex u and v there exists a vertex wadjacent to both of them. In this article the tensor product of G + H under some distancebased topological indices are investigated, when H is a strongly triangular graph. As a special case most of results given by Hoji, Luob and Vumara in [Wiener and vertex PI indices of Kronecker products of graphs, Discrete Appl. Math., 158 (2010), 1848-1855] will be deduced.

Let G be a connected simple (molecular) graph. The distance d (i, j) between two vertices i and j of G is equal to the length of a shortest path that connects i and j. In this paper we compute some distance based topological indices of H-phenylenic nanotorus. At first we obtain an exact formula for the Wiener index. As an application the Schultz index and modified Schultz index of this graph will be computed by using whose Wiener index. Finally, we compute eccentric connectivity index of this graph.

Forest roads are directions in natural habitats that used to transport wood products, secondary forest products and recreation. Constructing forest roads causes trees clearing with specified width thus lead to direct or indirect changes in forest ecosystems and forest environment. This study aims to assess the changes of diversity and richness indices in main and secondary forest roads in a part of Hyrcanian Forest. Sixteen 100-meters transects along main and secondary roads toward cut and fill slopes, were established perpendicular to the road in 0 (road edge), 5, 10, 15, 20, 30, 45, 60, 100 m distances. Within each, nine 1´2 m plots were sampled to record the herbaceous species. All transects were in Hornbeam-Beech forest type. Abundance of herbaceous species was recorded in each of the plots and was used to calculate Shannon-Wiener diversity index and richness index. Soil samples were taken from a depth of 0-10 cm above the center of each plot at 0, 5, 60 and 100 m to determine the physico-chemical properties of soil, and then transported to the laboratory. The results of this study showed that the diversity of herbaceous species in the main and secondary forest roads was not significantly different but in different distances from road edge, cut and fill slopes differences were significant. The results indicate that effect of forest roads is limited to the 60 meters of forest interior. Also based on the results of environmental factors and soil parameters, light is major factor to determinant of species abundance and distribution of them from road edge to forest interior.

Background & Aim: There are several methods for determination of occlusal vertical dimension. The vertical dimension of rest position, interocclusal distance and closest speaking space are two important methods. The purpose of this study was comparison the variability of interocclusal distance and closest speaking space in denture wearers.Method &Materials: The subjects were 34 edentulous patients (18 males & 16 females with mean age of 56) who had received complete dentures in the prosthodontics department of Isfahan dental school. They had good residual ridges. The dentures had correct clinical vertical dimension with 1-2mm overjet and 0.5 -1mm overbite. There was no evidence of neuromuscular and TMJ problems. The TOM guage was used for measuring the vertical dimension of rest position and «S» position.Results: The results showed that the mean and standard deviation of interocclusal distance were smaller than closest speaking space. Paired T-test and Levene's test were used for statistical analysis. There was a statistically difference between interocclusal distance and closest speaking space, so the interocclusal distance was less variable than closest speaking space (P<0.05).Conclusion: The closest speaking space during S position is affected by the occlusion, vertical and horizontal overlap of anterior teeth. These factors are up to dentist's judgement in complete denture and can influence the variability of vertical dimension of S position. Because of this variability it is recommended to use several methods for determining of vertical dimension.

The current study was carried to find distribution pattern of Zygophyllum eurypterum Ephedra strobilceae , Haloxylon aphyllum and Cornulaca monocantha in Poshtkouh rangelands in Yazd province using distance and quadrat indices. To do this, in a 20 ha area, 4 transects with a length of 400 m were established based on random-systematic method. Vegetation sampling was performed along each of transects .in 30 points. In each point, its distance to nearest plant, distance between mentioned plant and its nearest neighbor, and distance between the point and second plant was measured. Using these measurements, distance indices including; Eberhart, Hopkins and Holgate were calculated. To use quadrat indices, in each of abovementioned 30 points, quadrats with different sizes (according to plant kinds) were established and number of plants within quadrats were counted. Regarding obtained data from quadrats, indices of variance/mean, Morisita and standard Morisita indices were calculated. Results showed that Z. eurypterum, H aphyllum and C. monocantha distribution pattern was random, while E. strobilceae distribution pattern follows a clumped pattern. Also, it was cleared that the accuracy of distance methods was higher than quadrat methods and resulted to more reliable results in determination of plants distribution pattern.

Introduction1 Rice is a global important food and in Asia alone is the source of food for 3. 5 billion people. Such demand for rice imposes a plan to find new technology and approaches to replace old production methods. About 75% of global rice production is practiced on low lands. At field scale, rice compared to other plants receive two or three times more water and based on some calculations, about 34-43 percentage of global irrigation water or 24-30 percentage of drinking water consumed by rice plant. In this situation, the most important challenge with regard to rice production, water storage, increased water productivity and rice production is less than water. Recently, rice production systems such as rice alternate irrigation, where less water can be produced, has been considered as rice increasing demand for water in industry and cities have imposed the reduction of water consumption for agriculture. Rice is one of the most sensitive plants against water scarcity as a floodplain plant and has the most need for water in the cereals. Rice has the highest crop area than other irrigated plants. Materials and Methods This experiment was conducted as split-plot, using irrigation as main-plot at five levels (full irrigation, irrigation at ever 5, 8, 10, and 15 days), and planting distance as sub-plot at four levels (20×20, 25×25, 30×15, and 30×20 cm) within format of random complete block design with three replications. The study was performed in two years (2016-2017, and 2017-2018) in national rice research center. Soil samples were taken to determine the soil tissue, soil water holding capacity, and some chemical characters including EC, PH, and amount of Ca, Na, and Mg. Within firs 15 days after transplanting, the rotation irrigation was not employed so the plant be able to establish in the field. The plowing was performed in two times. The first plow in the late autumn and early winter and the second plow were perpendicular to the first plowing in the spring. Fertilization was done based on long term local practice. Transplanting was done in May, 15 and at this time transplants were 20-25 cm height carrying 4-5 leaves. All traits including stem and leaf dry matter, leaf area index (LAI), crop growth rate (CGR), net assimilation rate (NAR), leaf area ration (LAR), relative growth rate (RGR) and specific leaf area (SLA) were measured and calculated. SAS and SPSS software’ s were used for analysis of variance. Excel software was used for drawing slices. Results and Discussion ANOVA results showed that interaction of irrigation and planting distance were significantly (P≤ 0. 01) affected leaf and stem dry matter, LDW, TDW and CGR Individual effects of each treatment significantly affected the LAI and NAR but did not affect LAR, LWR, RGR, and SLA. As light absorption i a limiting factor in crops production, then where is no other environmental stress, increasing light absorb will increase crop production. In contrast to other crops light capture competitions a major issue for rice. Increasing panting density, vegetative growth and LAI would be lower and as planting density decreases, due to availability more spaces, both vegetative growth ad LAI increased. Conclusion In general, this study results showed that rotation irrigation significantly affected the rice growth indexes, and reduction levels of study traits depends on irrigation timing at growth stage. Planting distances showed that planting at 20×20 cm, provided the most optimum conditions for rice plants under different stress, the worst conditions resulted in 25×25 cm planting distance. At lower planting density, due to lower competition between plants till flowering time but after this stage, competition for photosynthetic materials increased among the seeds which can result in small dead seeds.

Helically-shaped chiral molecules are produced when benzene rings are angularly annulated to form Helicenes. Helicenes are ortho-condensed polycyclic aromatic compounds with the chemical formula $C_{4n+2} H_{2n+4}$ that have received attention due to their distinct structural, spectral, and optical properties, alluring physicochemical properties, and their application in various research fields. In this article, novel formulas of Szeged, Padmakar-Ivan, and Mostar indices are obtained through SMP-polynomials for Helicenes. These formulas do not need to count edges and can be calculated based on the number of benzene rings of Helicenes. Then, the results are displayed numerically and graphically and the topological indices are compared. Finally, the study explores the correlation between these indices and several physicochemical characteristics of different helicenes.