1,311 research outputs found
Intraspecific variation in thermal acclimation and tolerance between populations of the winter ant, Prenolepis imparis.
Thermal phenotypic plasticity, otherwise known as acclimation, plays an essential role in how organisms respond to short-term temperature changes. Plasticity buffers the impact of harmful temperature changes; therefore, understanding variation in plasticity in natural populations is crucial for understanding how species will respond to the changing climate. However, very few studies have examined patterns of phenotypic plasticity among populations, especially among ant populations. Considering that this intraspecies variation can provide insight into adaptive variation in populations, the goal of this study was to quantify the short-term acclimation ability and thermal tolerance of several populations of the winter ant, Prenolepis imparis. We tested for correlations between thermal plasticity and thermal tolerance, elevation, and body size. We characterized the thermal environment both above and below ground for several populations distributed across different elevations within California, USA. In addition, we measured the short-term acclimation ability and thermal tolerance of those populations. To measure thermal tolerance, we used chill-coma recovery time (CCRT) and knockdown time as indicators of cold and heat tolerance, respectively. Short-term phenotypic plasticity was assessed by calculating acclimation capacity using CCRT and knockdown time after exposure to both high and low temperatures. We found that several populations displayed different chill-coma recovery times and a few displayed different heat knockdown times, and that the acclimation capacities of cold and heat tolerance differed among most populations. The high-elevation populations displayed increased tolerance to the cold (faster CCRT) and greater plasticity. For high-temperature tolerance, we found heat tolerance was not associated with altitude; instead, greater tolerance to the heat was correlated with increased plasticity at higher temperatures. These current findings provide insight into thermal adaptation and factors that contribute to phenotypic diversity by revealing physiological variance among populations
Monte Carlo Tree Search in Finding Feasible Solutions for Course Timetabling Problem
We are addressing the course timetabling problem in this work. In a university, students can select their favorite courses each semester. Thus, the general requirement is to allow them to attend lectures without clashing with other lectures. A feasible solution is a solution where this and other conditions are satisfied. Constructing reasonable solutions for course timetabling problem is a hard task. Most of the existing methods failed to generate reasonable solutions for all cases. This is since the problem is heavily constrained and an effective method is required to explore and exploit the search space. We utilize Monte Carlo Tree Search (MCTS) in finding feasible solutions for the first time. In MCTS, we build a tree incrementally in an asymmetric manner by sampling the decision space. It is traversed in the best-first manner. We propose several enhancements to MCTS like simulation and tree pruning based on a heuristic. The performance of MCTS is compared with the methods based on graph coloring heuristics and Tabu search. We test the solution methodologies on the three most studied publicly available datasets. Overall, MCTS performs better than the method based on graph coloring heuristic; however, it is inferior compared to the Tabu based method. Experimental results are discussed
L-Lysine Imprinted Nanoparticles for Antibody Biorecognition
The aim of this study was to prepare L-lysine-imprinted poly(HEMA-MAAsp) nanoparticles which can
be used for the adsorption of IgG from aqueous solutions. L-lysine was complexed with MAAsp and Llysine-
imprinted poly(HEMA-MAAsp) nanoparticles were synthesized by miniemulsion polymerization. Also,
non-imprinted nanoparticles were synthesized without L-lysine for control purpose. L-lysine-imprinted
poly(HEMA-MAAsp) nanoparticles were characterized by means of elemental analysis, Fourier transform
infrared spectroscopy (FTIR) and transmission electron microscopy (TEM).
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3500
An effective hybrid local search approach for the post enrolment course timetabling problem
We address the post enrolment course timetabling (PE-CTT) problem in this paper. PE-CTT is known as an NP-hard problem that focuses on finding an efficient allocation of courses onto a finite number of time slots and rooms. It is one of the most challenging resources allocation problems faced by universities around the world. This work proposes a two-phase hybrid local search algorithm to address the PE-CTT problem. The first phase focuses on finding a feasible solution, while the second phase tries to minimize the soft constraint violations of the generated feasible solution. For the first phase, we propose a hybrid of Tabu Search with Sampling and Perturbation with Iterated Local Search. We test the proposed methodology on the hardest cases of PE-CTT benchmarks. The hybrid algorithm performs well and our results are superior compared to the recent methods in finding feasible solutions. For the second phase, we propose an algorithm called Simulated Annealing with Reheating (SAR) with two preliminary runs (SAR-2P). The SAR algorithm is used to minimize the soft constraint violations by exploiting information collected from the preliminary runs. We test the proposed methodology on three publicly available datasets. Our algorithm is competitive with the standards set by the recent methods. In total, the algorithm attains new best results for 3 cases and new best mean results for 7 cases. Furthermore, it is scalable when the execution time is extended
Competition of exchange and crystal field interactions in cerium monopnictides and monochalcogenides
Preparation of Ion Imprinted SPR Sensor for Real-Time Detection of Silver(I) Ion from Aqueous Solution
The aim of the submitted study is to develop molecular imprinting based surface plasmon resonance
(SPR) sensor for real-time silver ion detection. For this purpose polymeric nanofilm layer on the gold SPR
chip surface was prepared via UV polymerization of acrylic acid at 395 nm for 30 minutes. N-methacryloyl-
L cysteine used as the functional monomer to recognize the silver(I) ions from the aqueous solutions and
methylene bisacrylamide used as the crosslinker for obtaining structural rigidity of the formed cavities.
Silver(I) solutions with different concentrations were applied to SPR system to investigate the efficiency of
the imprinted SPR sensor in real time. For the control experiments, non-imprinted SPR sensor was also
prepared as described above without addition of template “silver(I) ions”. Prepared SPR sensors were
characterized with atomic force microscopy (AFM). In order to show the selectivity of the silver(I) imprinted
SPR sensor, competitive adsorption of Cu(II), Pb(II), Ni(II) ions was investigated.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3489
Islet autoantibody status in a multi-ethnic UK clinic cohort of children presenting with diabetes.
OBJECTIVE: We prospectively determined islet autoantibody status in children presenting with diabetes to a single UK region in relation to ethnicity.
DESIGN: 316 (68.0% non-white) children presenting with diabetes between 2006 and 2013 were tested centrally for islet cell autoantibodies (ICA) and glutamic acid decarboxylase autoantibodies (GAD-65) at diagnosis, and if negative for both, tested for insulin autoantibodies (IAA). The assay used to measure GAD-65 autoantibodies changed from an in-house to a standardised ELISA method during the study.
RESULTS: Even with use of the standardised ELISA method, 25.8% of children assigned a diagnosis of type 1 diabetes still tested negative for all three autoantibodies. 30% of children assigned a diagnosis of type 2 diabetes were autoantibody positive, and these had the highest glycated haemoglobin (HbA1c) levels at 12 months follow-up compared with other groups (p value for analysis of variance <0.001), although the sample size was small. Autoantibody positivity was similar between non-white and white children regardless of assay used (60.0% (n=129) vs 56.4% (n=57), χ2=0.9, p=0.35), as was mean GAD-65 autoantibody levels, but fewer non-white children had two or more autoantibodies detectable (13% (n=28) vs 27.7% (n=28), χ2=12.1, p=0.001).
CONCLUSION: Islet autoantibody positivity was associated with a more severe phenotype, as demonstrated by poorer glycaemic control, regardless of assigned diabetes subtype. Positivity did not differ by ethnic group
- …