BH-centroids: A New Efficient Clustering Algorithm

The k-means algorithm is one of most widely used method for discovering clusters in data; however one of the main disadvantages to k-means is the fact that you must specify the number of clusters as an input to the algorithm. In this paper we present an improved algorithm for discovering clusters in data by first determining the number of clusters k, allocate the initial centroids, and then clustering data points by assign each data point to one centroid. We use the idea of Gravity, by assuming each data point in the cluster has a gravity that attract the other closest points, this leads each point to move toward the nearest higher gravity toward the nearest higher gravity point to have at the end one point for each cluster, which represent the centroid of that cluster. The measure of gravity of point (X) determined by its weight, which represent the number of points that use point X as the nearest point. Our algorithm employ a distance metric based (eg, Euclidean) similarity measure in order to determine the nearest or the similar point for each point. We conduct an experimental study with real-world as well as synthetic data sets to demonstrate the effectiveness of our techniques

Screening for Y-chromosome microdeletions in a population of infertile males in the Gaza Strip

Infertility is an extraordinary public health problem in the Arab world, as it affects about 15% of couples seeking children. The male partner is responsible for infertility in approximately half of these cases. Classic microdeletions of the Y-chromosome involving the azoospermia factor (AZF) regions are known to be associated with spermatogenic impairment, and non-obstructive azoospermia must be differentiated on the basis of endocrine evaluation and testicular biopsy. Partial AZFc deletions remain controversial because there is no clear agreement regarding their role in spermatogenic failure. In the current study, 50 fertile males (controls) and 125 patients with primary idiopathic male infertility were studied in order to describe the frequency of Y-chromosome mirodeletions among male infertility patients in the Gaza Strip-Palestine area. No Y chromosome classical microdeletions could be detected in any of the 125 infertile men, suggesting that ethnic factors, genetic background, and Y chromosome haplogroups are key factors in such deletions. On the other hand, six gr/gr and one b1/b3 AZFc partial deletions were detected in the infertile population. The gr/gr deletion was also noted in relatives of four of the six patients with this deletion, and in one of the fertile controls. In conclusion, our study shows that the incidence of Y-chromosome microdeletions in our population is rare; these data suggest that other genetic, epigenetic, nutritional and/or local factors are responsible for impairments in semen parameters observed in this Gazan population. We further hypothesise that the gr/gr deletion is not associated with male infertility, at least in this sub-group

Properties of cementless mortars activated by sodium silicate.

yesThe present paper reports the testing of 12 alkali-activated mortars and a control ordinary portland cement (OPC) mortar. The main aim is to develop cementless binder activated by sodium silicate powder. An alkali quality coefficient combining the amounts of main compositions of source materials and sodium oxide (Na2O) in sodium silicate is proposed to assess the properties of alkali activated mortars, based on the hydration mechanism of alkali-activated pastes. Fly ash (FA) and ground granulated blast-furnace slag (GGBS) were employed as source materials. The ratio of Na2O-to-source material by weight for different mortars ranged between 0.038 and 0.164; as a result, alkali quality coefficient was varied from 0.0025 to 0.0365. Flow loss of fresh mortar, and shrinkage strain, compressive strength and modulus of rupture of hardened mortars were measured. The compressive strength development of alkali activated mortar was also compared with the design equations for OPC concrete specified in ACI 209 and EC 2. Test results clearly showed that the flow loss and compressive strength development of alkali-activated mortar were significantly dependent on the proposed alkali quality coefficient. In particular, a higher rate of compressive strength development achieved at early age for GGBS-based alkali-activated mortar and at long-term age for FA-based alkali-activated mortar. In addition, shrinkage strain and modulus of rupture of alkali-activated mortar were comparable to those of OPC mortar

Chromosomal aberrations in males occupationally exposed to chemical pollutants in the gaza strip-palestine

Objective: This study was conducted to evaluate the frequency of chromosomal aberrations in peripheral blood lymphocytes from Palestinian males exposed to various chemical pollutants during their daily work. Subjects and Methods: The study population consisted of 32 males (mean age 35.5 years) distributed as: 14 farmers, 3 plumbers, 5 taxi drivers, 6 paint factory workers, and 4 gas station workers, exposed to pollutants like pesticide, petrol derivatives etc. The control group consisted of 10 healthy Palestinian individuals of the same age and gender, but not exposed directly to pollutants in their jobs. Chromosomes were prepared from peripheral blood lymphocyte cultures using standard methods. The evaluation of chromosomal aberrations was performed following the IPCS (International Program Chemical Safety) guidelines for the monitoring of genotoxicity effects of carcinogens in humans. Results: A significantly higher incidence (2.14%, p< 0.05) of chromosomal aberrations (chromatid breaks, iso-chromatid breaks, chromatid deletions, and acentric fragments) were detected in lymphocyte of the study population. Interestingly, no chromosomal damage at all was recorded in the control group lymphocyte. Conclusion: These results suggest that occupational exposure to chemical pollutants is the cause of the chromosomal aberrations observed in the study population, which could be related to exposure time, since chromosomal aberrations were more frequent in workers exposed for longer times. The increased chromosomal damage detected in the study population can be attributed to the complex mixture of genotoxic compounds to which

Nonlinear Analysis of Concrete Beams Strengthened with Steel Fiber-Reinforced Concrete Layer

The behavior of concrete beams strengthened with a steel fiber-reinforced concrete (SFRC) layer was studied by Nonlinear Finite Element Analysis using ANSYS software. Four beams that were experimentally tested in a previous research were considered. Beam B-1 is made of ordinary reinforced concrete, B-2 is made of SFRC material, B-3 is made of two parts, RC beam with SFRC overlay and B-4 is made of RC beam with SFRC underlay. Ordinary concrete as well as SFRC were modeled using the multi-linear isotropic hardening constants where they are assumed to have a linear behavior up to 30% of the compressive strength. Afterwards, a multi-linear stress-strain curve was defined. For reinforcing steel, a linear-elastic perfectly-plastic material model was used. Steel fiber reinforced concrete was modeled by the smeared modeling technique. The results obtained by FEA showed good agreement with those obtained by the experimental program. This research demonstrates the capability of FEA in predicting the behavior of beams strengthened with SFRC layer. It will help researchers in studying beams with different configurations without the need to go through the lengthy experimental testing programs