7,627 research outputs found
Working memory learning method and astrocytes number in different subfields of rat's Hippocampus
The aim of this study was evaluation of the astrocytes number in different subfields of rat's Hippocampus after spatial learning with usage of Morris Water Maze technique and working memory method. In this study, between 2005-2006 years in Pasteur institute of Iran-Tehran and histological department of Gorgan University with usage of Morris Water Maze and working memory technique, we used 14 male albino wistar rats. Seventh rats were in control group and 7 rats in working memory group. After histological preparation, the slides were stained with PTAH staining for showing the Astrocytes. Present results showed significant difference in astrocytes number in CA1, CA2 and CA3 areas of hippocampus between control and reference memory group. The number of astrocytes is increased in working memory group. Then we divided the hippocampus to three parts: Anterior, middle and posterior and with compare of different area (CA1, CA2 and CA3) of hippocampus, we found that the differences between Anterior-middle and Middle-Posterior of CA1 and CA2 area of hippocampus were significant, whereas the difference between Anterior-Posterior parts was not significant in CA1 and CA2 areas. In CA3 area, the difference between Anterior-Middle and Anterior-Posterior parts was significant, whereas the difference between middle and posterior parts was not significant. We concluded that the number of astrocytes increased due to spatial learning and working memory technique. © 2008 Science Publications
New control strategies for neuroprosthetic systems
The availability of techniques to artificially excite paralyzed muscles opens enormous potential for restoring both upper and lower extremity movements with\ud
neuroprostheses. Neuroprostheses must stimulate muscle, and control and regulate the artificial movements produced. Control methods to accomplish these tasks include feedforward (open-loop), feedback, and adaptive control. Feedforward control requires a great deal of information about the biomechanical behavior of the limb. For the upper extremity, an artificial motor program was developed to provide such movement program input to a neuroprosthesis. In lower extremity control, one group achieved their best results by attempting to meet naturally perceived gait objectives rather than to follow an exact joint angle trajectory. Adaptive feedforward control, as implemented in the cycleto-cycle controller, gave good compensation for the gradual decrease in performance observed with open-loop control. A neural network controller was able to control its system to customize stimulation parameters in order to generate a desired output trajectory in a given individual and to maintain tracking performance in the presence of muscle fatigue. The authors believe that practical FNS control systems must\ud
exhibit many of these features of neurophysiological systems
An Account of Clitics in Shabaki with Reference to Wackernagels Law
In this paper the behavior of clitics in Shabaki a northwestern Indo-Iranian language spoken in Nineveh plains in Iraq is discussed in detail with respect to forms and distributions and much more interestingly with respect to sensitivity to Wackernagel s Law The paper also addresses clitic doubling clustering and climbing which may be considered the peculiar defining features of Shabaki They could be added to nouns pronouns verbs prepositions and other clitics Shabaki is a language with multiple cliticization and is surprisingly complicated with respect to this phenomenon It has an intricate system of clitics which include subject pronominal clitics object pronominal clitics dative and accusative possessive pronominal clitics demonstrative pronoun clitics ezafe clitics diminutive clitics additive clitics aspectual clitics tense clitics copular clitics and negative clitic
Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current
In this paper interleaving and switched-capacitor techniques are used to introduce a high step-up DC-DC converter for renewable energy systems application. The proposed converter delivers high voltage gain without utilizing transformer or excessive duty cycle and features ripple-free input current which results in lower conduction losses and decreased electromagnetic interference (EMI). Lower output capacitance is another advantage of proposed converter, leading to smaller size and lower cost. Furthermore lower voltage stress on switches allows the utilization of switches with low resistance. Simulation results verify the performance of suggested converter
Newly Discovered RR Lyrae Stars in the SDSSXPanXSTARRS1XCatalina Footprint
We present the detection of 6,371 RR Lyrae (RRL) stars distributed across
~14,000 deg^2 of the sky from the combined data of the Sloan Digital Sky Survey
(SDSS), the Panoramic Survey Telescope and Rapid Response System 1 (PS1), and
the second photometric catalogue from the Catalina Survey (CSDR2), out of
these, ~2,021 RRL stars (~572 RRab and 1,449 RRc) are new discoveries. The RRL
stars have heliocentric distances in the 4--28 kpc distance range. RRL-like
color cuts from the SDSS and variability cuts from the PS1 are used to cull our
candidate list. We then use the CSDR2 multi-epoch data to refine our sample.
Periods were measured using the Analysis of Variance technique while the
classification process is performed with the Template Fitting Method in
addition to the visual inspection of the light curves. A cross-match of our RRL
star discoveries with previous published catalogs of RRL stars yield
completeness levels of ~50% for both RRab and RRc stars, and an efficiency of
~99% and ~87% for RRab and RRc stars, respectively. We show that our method for
selecting RRL stars allows us to recover halo structures. The full lists of all
the RRL stars are made publicly available.Comment: 14 pages, 11 figures. Accepted 2014 March 30. Received 2014 March 12;
in original form 2013 November 2
Spectral characteristics of normal and nutrient-deficient maize leaves
Reflectance, transmittance and absorbance spectra of normal and six types of mineral-deficient (N,P,K,S,Mg and Ca) maize (Zea mays L.) leaves were analyzed at 30 selected wavelengths along the electromagnetic spectrum from 500 to 2600 nm. Chlorophyll content and percent leaf moisture were also determined. Leaf thermograms were obtained for normal, N- and S- deficient leaves. The results of the analysis of variance showed significant differences in reflectance, transmittance and absorbance in the visible wavelengths among leaf numbers 3, 4, and 5, among the seven nutrient treatments, and among the interactions of leaves and treatments. In the reflective infrared wavelengths only treatments produced significant differences. The chlorophyll content of leaves was reduced in all deficiencies in comparison to controls. Percent moisture was increased in S-, Mg- and N- deficiencies. Positive correlation (r = 0.707) between moisture content and percent absorption at both 1450 and 1930 nm were obtained. Polynomial regression analysis of leaf thickness and leaf moisture content showed that these two variables were significantly and directly related (r = 0.894)
Carbon Nanotubes: Synthesis via Flame Fragment Deposition (FFD) Method from Liquefied Petroleum Gas
تستخدم الدراسة الحالية طريقة ترسيب شظايا اللهب (FFD) لتخليق الأنابيب النانوية الكربونية (CNTs) من غاز البترول المسال العراقي (LPG) كمصدر للكربون. تم استخدام مفاعل محلي الصنع لتنفيذ إجراءات التحضير. للتخلص من الشوائب غير المتبلورة، تم صوتنة الأنابيب النانوية الكربونية في محلول بيروكسيد الهيدروجين ((30% wt H2O2 في درجة حرارة الغرفة ، متبوعًا بالصوتنة في حمام الأسيتون لإزالة الهيدروكربونات العطرية متعددة الحلقات (PAHs) المتولدة أثناء احتراق غاز البترول المسال. تم فحص الناتج المحضر، ومقارنته مع انابيب كربونية متعددة الجدران قياسية (MWCNTs(95%), Sigma (Aldrich باستخدام حيود الأشعة السينية (XRD) ، مطيافية رامان، التحليل الحراري الوزني (TGA) ، مطيافية الأشعة السينية المشتتة للطاقة (EDS) ، المسح الطيفي الإلكتروني (SEM) ، والمجهر الإلكتروني النافذ (TEM). في ظل الظروف التجريبية المطبقة، تؤكد نتائج التحضير التي تم الحصول عليها تخليق الأنابيب النانوية الكربونية متعددة الجدران (MWCNTs) مع نسبة من الأنابيب النانوية الكربونية قليلة الجدران (FWCNTs). للأنابيب النانوية الكربونية بنقاوة تزيد عن 65 في المائة وبمتوسط قطرها يتراوح من 31.26 إلى 78.00 نانومتر.The current study uses the flame fragment deposition (FFD) method to synthesize carbon nanotubes (CNTs) from Iraqi liquefied petroleum gas (LPG), which is used as a carbon source. To carry out the synthesis steps, a homemade reactor was used. To eliminate amorphous impurities, the CNTs were sonicated in a 30 percent hydrogen peroxide (H2O2) solution at ambient temperature. To remove the polycyclic aromatic hydrocarbons (PAHs) generated during LPG combustion, sonication in an acetone bath is used. The produced products were investigated and compared with standard Multi-walled carbon nanotube MWCNTs (95%), Sigma, Aldrich, using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), Raman spectroscopy, scanning electron spectroscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Transmission Electron Microscopy (TEM). Under the applied experimental circumstances, the obtained characterization data confirm the synthesis of multi-wall carbon nanotubes (MWCNTs) with portion from few wall carbon nanotubes (FWCNTs). The average diameter of synthesized Carbon nanotubes ranged from 31.26 to 78.00 nm, with a purity of more than 65 percent
Physical Properties of Cu Doped ZnO Nanocrystiline Thin Films
تم تصنيع اغشية أكسيد الزنك البلورية النانوية المطعمة بالنحاس (ZnO: Cu)بتراكيز مختلفة .. تم ترسيب (0 ، 6 ، 9 ، 12 ، 18) ٪ من النحاس على ركيزة زجاجية باستخدام تقنية ترسب الليزر النبضي (PLD) وبتراكيز مختلفة. وقد تم توصيف بلورات ZnO: Cu النانوية بواسطة أطياف UV-VIS ، حيود الأشعة السينية (XRD) ومجهر القوة الذرية (AFM). تم استخدام التحليل الطيفي للأشعة المرئية وفوق البنفسجية لتحديد نوع وقيمة فجوة الطاقة الضوئية ، بينما تم استخدام حيود الأشعة السينية لفحص الهيكل وتحديد حجم البلورات. تم استخدام مجاهر القوة الذرية لدراسة تكوين سطح المواد المترسبة. تم استخدام التحليل الطيفي للأشعة المرئية وفوق البنفسجية لتحديد نوع وقيمة فجوة الطاقة الضوئية. Thin films of ZnO nano crystalline doped with different concentrations (0, 6, 9, 12, and 18 )wt. % of copper were deposited on a glass substrate via pulsed laser deposition method (PLD). The properties of ZnO: Cu thin-nanofilms have been studied by absorbing UV-VIS, X-ray diffraction (XRD) and atomic force microscopes (AFM). UV-VIS spectroscopy was used to determine the type and value of the optical energy gap, while X-ray diffraction was used to examine the structure and determine the size of the crystals. Atomic force microscopes were used to study the surface formation of precipitated materials. The UV-VIS spectroscopy was used to determine the type and value of the optical energy gap
Scale-free equilibria of self-gravitating gaseous disks with flat rotation curves
We introduce exact analytical solutions of the steady-state hydrodynamic
equations of scale-free, self-gravitating gaseous disks with flat rotation
curves. We express the velocity field in terms of a stream function and obtain
a third-order ordinary differential equation (ODE) for the angular part of the
stream function. We present the closed-form solutions of the obtained ODE and
construct hydrodynamical counterparts of the power-law and elliptic disks, for
which self-consistent stellar dynamical models are known. We show that the
kinematics of the Large Magellanic Cloud can well be explained by our findings
for scale-free elliptic disks.Comment: AAS preprint format, 21 pages, 8 figures, accepted for publication in
The Astrophysical Journa
Optimal route planning of agricultural field operations using ant colony optimization
Farming operations efficiency is a crucial factor that determines the overall operational cost in agricultural production systems. Improved efficiency can be achieved by implementing advanced planning methods for the execution of field operations dealing, especially with the routing and area coverage optimisation aspects. Recently, a new type of field area coverage patterns, the B-patterns, has been introduced. B-patterns are the result of a combinatorial optimisation process that minimizes operational criterions such as, the operational time, non-working travelled distance, fuel consumption etc. In this paper an algorithmic approach for the generation of B-patterns based on ant colony optimisation is presented. Ant colony optimization metaheuristic was chosen for the solution of the graph optimisation problem inherent in the generation of B-patterns. Experimental results on two selected fields were presented for the demonstration of the effectiveness of the proposed approach. Based on the results, it was shown that it is feasible to use ant colony optimization for the generation of optimal routes for field area coverage while tests made on the resulting routes indicated that they can be followed by any farm machine equipped with auto-steering and navigation systems
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