543 research outputs found

    Multiple positive solutions to third-order three-point singular semipositone boundary value problem

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    By using a specially constructed cone and the fixed point index theory, this paper investigates the existence of multiple positive solutions for the third-order three-point singular semipositone BVP: \begin{cases} x'''(t)-\ld f(t,x) =0, &t\in(0,1); [.3pc] x(0)=x'(\eta)=x''(1)=0, & \end{cases} where 1/2<η<1{1/2}<\eta<1, the non-linear term f(t,x):(0,1)\times(0,+\i)\to (-\i,+\i) is continuous and may be singular at t=0t=0, t=1t=1, and x=0x=0, also may be negative for some values of tt and xx, \ld is a positive parameter.Comment: 14 page

    Investigation of Low Cost Solar Drying of Apricots for Tajikistan

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    Dried apricots are one of Tajikistan’s major export products. The country wants to expand its production in the southern region. However, the producers don’t have the expertise needed to produce dried apricots that meet the quality requirements of the European Union and other potential export markets. Local producers in southern Tajikistan would benefit from improvements in methods of applying sulfur and drying the apricots. This would allow them to gain a share of global markets. Methods that were studied include sulfur treatment prior to drying and approaches for rapidly drying the apricots while preventing contamination. Because the project has just started, efforts are focused on developing the methods to determine the quality of apricots. Preliminary tests were conducted on dried apricots purchased from local stores or on fresh apricots dried by project personnel. These will serve as standards against which Tajikistan dried apricots will be compared. Quality factors evaluated included color, microbial content, sulfur content, water activity, percent soluble solids, and moisture content. This paper reports results of preliminary quality tests conducted on dried apricots purchased from stores in West Lafayette and Lafayette, Indiana. To prepare for future studies, thin layer drying tests were conducted on fresh apricots purchased from local stores and apricots grown in Michigan which were obtained from a contact in the Lafayette Farmer’s Market. These apricots were treated and dried in a thin layer dryer at three different temperatures to better understand factors that affect drying rate. Quality parameters of these dried apricots were also determined

    On the integration of metamorphic testing and model checking

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    Metamorphic testing, an innovative software testing technique, generates test cases based on domain specific properties. Model checking is a technique that verifies software designs against system properties. Motivated by the fact that both techniques are based on some properties of software under development, we investigate how to integrate metamorphic testing and model checking. This paper will introduce and discuss some potential topics on this new research direction

    Chromatin status and transcription factor binding to gonadotropin promoters in gonadotrope cell lines.

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    BackgroundProper expression of key reproductive hormones from gonadotrope cells of the pituitary is required for pubertal onset and reproduction. To further our understanding of the molecular events taking place during embryonic development, leading to expression of the glycoproteins luteinizing hormone (LH) and follicle-stimulating hormone (FSH), we characterized chromatin structure changes, imparted mainly by histone modifications, in model gonadotrope cell lines.MethodsWe evaluated chromatin status and gene expression profiles by chromatin immunoprecipitation assays, DNase sensitivity assay, and RNA sequencing in three developmentally staged gonadotrope cell lines, αT1-1 (progenitor, expressing Cga), αT3-1 (immature, expressing Cga and Gnrhr), and LβT2 (mature, expressing Cga, Gnrhr, Lhb, and Fshb), to assess changes in chromatin status and transcription factor access of gonadotrope-specific genes.ResultsWe found the common mRNA α-subunit of LH and FSH, called Cga, to have an open chromatin conformation in all three cell lines. In contrast, chromatin status of Gnrhr is open only in αT3-1 and LβT2 cells. Lhb begins to open in LβT2 cells and was further opened by activin treatment. Histone H3 modifications associated with active chromatin were high on Gnrhr in αT3-1 and LβT2, and Lhb in LβT2 cells, while H3 modifications associated with repressed chromatin were low on Gnrhr, Lhb, and Fshb in LβT2 cells. Finally, chromatin status correlates with the progressive access of LHX3 to Cga and Gnrhr, followed by PITX1 binding to the Lhb promoter.ConclusionOur data show the gonadotrope-specific genes Cga, Gnrhr, Lhb, and Fshb are not only controlled by developmental transcription factors, but also by epigenetic mechanisms that include the modulation of chromatin structure, and histone modifications

    Asymmetric natural convection flow in three dimensional attic space

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    © 2019 Author(s). Natural convection in an attic space with top cooling is investigated by three dimensional numerical simulation for a wide range of Rayleigh numbers. The numerical results show the development of natural convection flow in attic space. Three stages: an initial stage, a transitional stage and a fully developed stage are involved. At higher Rayleigh numbers, the flow in the attic space is three dimensional and asymmetry with respect to geometric symmetry plane. The critical Rayleigh number for asymmetric flow is found

    Strain Sensitive Coax Cable Sensors for Monitoring Structures

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    The invention provides increased structural monitoring systems that have sensitive continuous coaxial cable sensors. A preferred embodiment sensor cable of the invention includes an inner conductor, a dielectric jacket, and an outer conductor that is configured to passively deform responsively to strain in an associated structure. The deformation can be aided by the physical structure of the dielectric jacket, the outer conductor, or a combination of both. The deformation translates strain into a measurable change in a reflection coefficient associated with the outer conductor

    The oxygen isotopic composition of phosphate in river water and its potential sources in the Upper River Taw catchment, UK

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    The need to reduce both point and diffuse phosphorus pollution to aquatic ecosystems is widely recognised and in order to achieve this, identification of the different pollutant sources is essential. Recently, a stable isotope approach using oxygen isotopes within phosphate (δ18OPO4) has been used in phosphorus source tracing studies. This approach was applied in a one-off survey in September 2013 to the River Taw catchment in south-west England where elevated levels of phosphate have been reported. River water δ18OPO4 along the main channel varied little, ranging from + 17.1 to + 18.8‰. This was no > 0.3‰ different to that of the isotopic equilibrium with water (Eδ18OPO4). The δ18OPO4 in the tributaries was more variable (+ 17.1 to + 18.8‰), but only deviated from Eδ18OPO4 by between 0.4 and 0.9‰. Several potential phosphate sources within the catchment were sampled and most had a narrow range of δ18OPO4 values similar to that of river Eδ18OPO4. Discharge from two waste water treatment plants had different and distinct δ18OPO4 from one another ranging between + 16.4 and + 19.6‰ and similar values to that of a dairy factory final effluent (+ 16.5 to + 17.8‰), mains tap water (+ 17.8 to + 18.4‰), and that of the phosphate extracted from river channel bed sediment (+ 16.7 to + 17.6‰). Inorganic fertilizers had a wide range of values (+ 13.3 to + 25.9‰) while stored animal wastes were consistently lower (+ 12.0 to + 15.0‰) than most other sources and Eδ18OPO4. The distinct signals from the waste water treatment plants were lost within the river over a short distance suggesting that rapid microbial cycling of phosphate was occurring, because microbial cycling shifts the isotopic signal towards Eδ18OPO4. This study has added to the global inventory of phosphate source δ18OPO4 values, but also demonstrated the limitations of this approach to identifying phosphate sources, especially at times when microbial cycling is high

    Inducible and Selective Erasure of Memories in the Mouse Brain via Chemical-Genetic Manipulation

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    SummaryRapid and selective erasures of certain types of memories in the brain would be desirable under certain clinical circumstances. By employing an inducible and reversible chemical-genetic technique, we find that transient αCaMKII overexpression at the time of recall impairs the retrieval of both newly formed one-hour object recognition memory and fear memories, as well as 1-month-old fear memories. Systematic analyses suggest that excessive αCaMKII activity-induced recall deficits are not caused by disrupting the retrieval access to the stored information but are, rather, due to the active erasure of the stored memories. Further experiments show that the recall-induced erasure of fear memories is highly restricted to the memory being retrieved while leaving other memories intact. Therefore, our study reveals a molecular genetic paradigm through which a given memory, such as new or old fear memory, can be rapidly and specifically erased in a controlled and inducible manner in the brain
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