481 research outputs found
Trichomyrmex shakeri Sharaf & Al Dhafer, sp. nov.
No full textTrichomyrmex shakeri Sharaf & Al Dhafer sp. nov. urn:lsid:zoobank.org:act:CBBBD8CB-46EF-4D9E-9BBC-4252822A9206 Fig. 13 A–C Etymology The new species has been named in honor of the late Egyptian writer Mahmoud M. Shaker (1909–1997). Material examined Holotype SAUDI ARABIA: worker, Riyadh, Wadi Hanifa, 24.90˚ N, 46.18˚ E, alt. 814 m, 12 Oct. 2015, Aldhafer et al. leg. (KSMA). Paratypes SAUDI ARABIA: 1 w, same data as the holotype (KSMA); 4 w, Riyadh, Wadi Hanifa, 24.90˚ N, 46.18˚ E, alt. 806 m, 29 Apr. 2015, Aldhafer et al. leg. (1 in CASC: CASENT0922068; 3 in KSMA). Type material is collected by pitfall traps. Description MEASUREMENTS. Holotype, worker. TL 2.07; HL 0.62; HW 0.56; SL 0.48; EL 0.19; ML 0.56; PW 0.31; PTL 0.14; PTW 0.09; PPL 0.08; PPW 0.15; CI 90; EI 34; SI 86. WORKER. TL 1.94–2.33; HL 0.58–0.67; HW 0.52–0.64; SL 0.36–0.48; EL 0.18–0.21; ML 0.53–0.66; PW 0.29–0.34; PTL 0.14–0.18; PTW 0.09–0.13; PPL 0.08–0.15; PPW 0.14–0.18; CI 85–96; EI 31–37; SI 68–86 (n = 5). HEAD. Slightly longer than broad and broader anteriorly than posteriorly, with emarginated posterior margin and feebly convex sides; anterior clypeal margin nearly straight or feebly convex; eyes large (EL 0.31–0.36 × HW), with 11 ommatidia in longest row; scapes when laid back from their insertions surpassing posterior margin of head by about one third of eye length. MESOSOMA. Promesonotum distinctly convex in profile; metanotal groove impressed. PILOSITY. Underside of head with few short straight hairs, not forming a psammophore; cephalic surface and mandibles with sparse short hairs, anterior clypeal margin with a median long hair and two pairs of long hairs on each side; antennae with dense appressed pubescence; mesosoma without hairs except for few sparse appressed pubescence on promesonotum. PETIOLE. With one pair of long, backward directed hairs. POSTPETIOLE. With two pairs; first gastral tergite bare except for few sparse appressed pubescence, the remaining gastral tergites with some long hairs. SCULPTURE. Cephalic surface smooth and shining except posterior margin of head, area in front of eyes and mandibles longitudinally rugulose; promesonotal dorsum faintly irregularly sculptured; mesopleura, propodeum, petiole and postpetiole densely punctulate-reticulate; gaster smooth and shining. COLOUR. Uniform yellow, eyes black, mandibular teeth dark brown. Differential diagnosis Among the Arabian Trichomyrmex species, T. shakeri sp. nov. is a conspicuous species, quickly identified by the uniform yellow colour and the exceptionally larger eyes (EL 0.31–0.36 × HW) compared to other sympatric species. Trichomyrmex shakeri sp. nov. is superficially similar to T. santschii (Forel, 1907) from North Africa (Tunisia) in colour and measurements, but it can be readily separated by the absence of the psammophore, which is well-developed in T. santschii. Ecological and biological notes This species is considered uncommon. Only six workers were collected in 150 pitfall traps run for one year at the type locality, a relatively pristine section of Wadi Hanifa (Fig. 13 D). Other sampling methods (soil sifting, light traps, beating sheets) were not successful in adding more material.Published as part of Mostafa R. Sharaf, Shehzad Salman, Hathal M. Al Dhafer, Shahid A. Akbar, Mahmoud S. Abdel-Dayem & Abdulrahman S. Aldawood, 2016, Taxonomy and distribution of the genus Trichomyrmex Mayr, 1865 (Hymenoptera: Formicidae) in the Arabian Peninsula, with the description of two new species, pp. 1-36 in European Journal of Taxonomy 246 on pages 28-31, DOI: 10.5852/ejt.2016.246, http://zenodo.org/record/19304
Scaling purely elastic instability of strongly shear thinning polymer solutions
No full textFlow of viscoelastic polymer solutions in curved channels exhibits instability caused by the elastic nature of polymers even at low Reynolds numbers. However, scaling of the onset of this purely elastic instability in semidilute polymer solutions has not been previously reported. Here we experimentally investigate the flow of highly elastic polymer solutions above their overlap concentrations using pressure measurements and particle image velocimetry. We demonstrate that the onset of instability can be scaled by including shear dependent rheological properties of the polymer solutions in the nonlinear stability analysis. As a result, a universal criterion as function of normalized polymer concentration is provided for scaling the onset of purely elastic instability in the semidilute regime regardless of the type and molecular weight of the polymer
Control methods of alfalfa witches’ broom phytoplasma disease
No full textAlfalfa witches’ broom (AWB) is the most important alfalfa disease in Iran. The infected plants appear severely stunted, erect
and excessively branched and yellowish. Different methods of AWB disease control were studied in a randomized complete
blocks design at three replications in Ardakan (Yazd province, Iran). The methods were dense planting of alfalfa, use of sorghum
as windbreak and spraying with metasystox-R. The results indicated that sorghum and metasystox-R had no significant effect
on disease control. Only dense planting of alfalfa in the field using twice the usual seed quantity significantly reduced the
disease incidence by 16% compared the control that resulted at the 5% probability level. According to this findings, dense planting
of alfalfa stands is recommended for the prevention of AWB disease in alfalfa farms
Strong Scalability Studies for the 2-D Poisson Equation on the Taki 2021 Cluster with Historical Comparison
No full textThe new 2021 nodes in the cluster taki in the UMBC High Performance Computing Facility contain two 24core Intel Cascade Lake CPUs and 192 GB of memory per node, connected by an high-performance InfiniBand interconnect. Parallel performance studies for the memory-bound test problem of the Poisson equation in two spatial dimensions yield several conclusions: Strong scalability studies demonstrate excellent performance when using multiple nodes due to the low latency of the high-performance interconnect and good speedup when using all cores of the multi-core CPUs. For the largest numbers of processes per node, the runtime for the code is not significantly reduced, a typical behavior characteristic of memory-bound code. Comparisons to results on past clusters in HPCF bring out that core-per-core performance of serial code improvements has improved again, demonstrating the quality of the newest CPUs. Also node-per-node performance of parallel code continues to improve due to the larger number of cores available on a node. albeit we have fewer nodes in taki 2021 than we had in previous partitions.The hardware used in the computational studies is part of the UMBC High Performance Computing Facility (HPCF). The facility is supported by the U.S. National Science Foundation through the MRI program (grant nos. CNS–0821258, CNS–1228778, OAC–1726023, and CNS–1920079) and the SCREMS program (grant no. DMS–0821311), with additional substantial support from the University of Maryland, Baltimore County (UMBC). See hpcf.umbc.edu for more information on HPCF and the projects using its resources. Co-author Ehsan Shakeri was supported by UMBC as HPCF RA.https://userpages.umbc.edu/~gobbert/papers/PoissonHPCF20241.pd
Screening of several biological activities induced by different sesquiterpene lactones isolated from Centaurea behen L. and Rhaponticum repens (L.) Hidalgo
No full textThis study aims to evaluate the in vitro cytotoxic, in vitro and in ovo anti-angiogenic effects and antimicrobial activity of sesquiterpene lactones (SLs) from two plants Centaurea behen and Rhaponticum repens (L.). Five SLs, including cynaropicrin (1), 4Î2,15-dehydro-3-dehydrosolstitialin A (2), aguerin B (3), janerin (4), cebellin E (5), and a flavone hispidulin (6) were isolated from C. behen (compounds 1â3) and R. repens (compounds 4â6). Cynaropicrin (1) and aguerin B (3) were characterised by strong cytotoxic activities against A2780 cells with IC50 values of 1.15 and 1.62 Î1⁄4g mLâ1, respectively, comparable to that of doxorubicin (IC50 = 1.17 Î1⁄4g mLâ1). The anti-angiogenic study showed the remarkable inhibitory effect of cynaropicrin (1) and aguerin B (3) on the proliferation and migration of HUVECs. In addition, cynaropycrin and aguerin B exhibited significant angio-inhibitory effects in CAM assay. These findings may be useful for the development of novel chemotherapeutic agents for the treatment of cancer
The Study of the Validity and Reliability of Hardiness Scale for University Students
No full textThe objective of this study was to evaluate the psychometric properties of “Hardiness” scale for university students. The instrument used was Lang and Goulet hardiness scale, translated from English into Persian by using back-translation technique. The “Hardiness” scale for university (Shahed, Tehran & Beheshti). Factor analysis revealed three factors (control, commitment, and challenge) explained 30% of the variance. For all items of this questionnaire construct validity was (r=0.64), Internal consistency coefficient was obtained in three ways (cronbach’s alpha=0.82), Test=retest reliability was r=0.71) and Split-half reliability was r=0.76). The results indicated acceptable validity and reliability of the scale as a whole and for subscales. These preliminary results provide support for using LGHS to measure hardiness levels in Iranian university students and can be used to assess the hardiness of other populations
Opium use, cigarette smoking, and alcohol consumption in relation to pancreatic cancer
No full textBackground and Aims: Although several studies have suggested opium as a risk factor for cancers of the esophagus, stomach, larynx, lung, and bladder, no previous study has examined the association of opium with pancreatic cancer. We aimed to study the association between opium use and risk of pancreatic cancer in Iran, using a case-control design. We also studied the association of cigarette smoking and alcohol consumption with pancreatic cancer, for which little information was available from this population. Methods: Cases and controls were selected from patients who were referred to 4 endoscopic ultrasound centers in Tehran, Iran. We recruited 316 histopathologically (all adenocarcinoma) and 41 clinically diagnosed incident cases of pancreatic cancer, as well as 328 controls from those with a normal pancreas in enodosonography from January 2011 to January 2015. We used logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results: After adjustment for potential confounders, opium use (OR 1.91; 95% CI 1.06-3.43) and alcohol consumption (OR 4.16; 95% CI 1.86-9.31) were significantly associated with an increased risk of pancreatic cancer. We did not find an association between ever tobacco smoking and pancreatic cancer risk (OR 0.93; 95% CI 0.62-1.39). Conclusion: In our study, opium use and alcohol consumption were associated with an increased risk of pancreatic cancer, whereas cigarette smoking was not. Copyright © 2016 the Author(s). Published by Wolters Kluwer Health, Inc. All rights reserved
Whole slide imaging systems for digital pathology
No full textDigital pathology is based on the use of digital images of tissues for diagnosis of diseases. In the emerging clinical practice of digital pathology, images of tissue slides are acquired with a high-resolution and high-throughput automated microscope, a so called Whole Slide Imaging (WSI) system. We designed, built and characterized a modular WSI platform for conducting two- and three-dimensional brightfield microscopy, the most common modality in this field
Comparative proteome profiling in exosomes derived from porcine colostrum versus mature milk
No full textImpact of the ratio of n6:n3 fatty acids in the maternal diet on milk pig exosome proteome profiles
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