High root concentration and uneven ectomycorrhizal diversity near Sarcodes sanguinea (Ericaceae): a cheater that stimulates its victims?

Published versio

Experimental investigation of precoding for EM exposure reduction

Reduction of human exposure to electromagnetic (EM) radiation from communications devices without compromising link quality is of importance as people spend more and more time using devices with wireless connectivity. This paper considers the idea of designing a low complexity baseband precoder to reduce user EM exposure for the user scenario of a laptop making an uplink connection to an access point terminal in a picocell environment. The design of the precoder is supported by channel sounding measurements and a ten-fold reduction in user exposure is indicated

Thermal response of skin diseased tissue treated by plasmonic nanoantenna

The thermal distribution in the diseased tissue treated by different methods faces the problem of an uncontrollable defused heat. In the present article, we use a plasmonic bowtie nanoantenna working in the near infrared region to enhance the temperature confinement in the tissue. The Computer Simulation Technology Studio Suite package version 2019 was used to execute the design of both plasmonic nanoantenna and the tissue. Gold nanostructure and silicon carbide dioxide are the components the plasmonic nanoantenna in the bowtie shape. The results showed that the distance between the tumor tissue and the antenna is important to determine the intensity field where the maximum field is 5.9*107 V/m at a distance of 100 nm. The maximum specific absorption rate is 1.92*1011 W/kg at a similar distance which gives a higher temperature in the tissue of 580 Co. It is concluded that from the obtained results that the near infrared (1064 nm) resonance wavelength is recommended in the treatment of cancer cell by plasmonic bowtie nanoantenna because higher intensity field is generated. The closer distance to the nanoantenna gives higher temperature in the tissue while the temperature gradually decreases in the tissue till 400 nm where no valuable temperature was detected

Impact of curriculum modifications on access to the general education curriculum for students with disabilities

This is the publisher's version, also found here: http://cec.metapress.com/content/4r15312203720k10/?p=894108fe09e449b9a6b0c2c7538086b1&pi=4This study investigated whether curriculum modifications predicted student and teacher behaviors related to the general education curriculum and if there were differences in ecological, student, and teacher variables depending on the presence of such curriculum modifications. The study observed 45 high school students with disabilities during instruction in core content areas. Findings indicated that there were significant differences in student and teacher variables depending on the presence of curriculum modifications. When curriculum modifications were provided, students were engaged in more academic-related responses and fewer competing behaviors and teachers were engaged in fewer classroom management activities. Implications and recommendations from these findings are provided pertaining to the importance and implementation of curriculum modifications for students with disabilities in general education settings

Rate-Splitting Multiple Access for Uplink Massive MIMO With Electromagnetic Exposure Constraints

Over the past few years, the prevalence of wireless devices has become one of the essential sources of electromagnetic (EM) radiation to the public. Facing with the swift development of wireless communications, people are skeptical about the risks of long-term exposure to EM radiation. As EM exposure is required to be restricted at user terminals, it is inefficient to blindly decrease the transmit power, which leads to limited spectral efficiency and energy efficiency (EE). Recently, rate-splitting multiple access (RSMA) has been proposed as an effective way to provide higher wireless transmission performance, which is a promising technology for future wireless communications. To this end, we propose using RSMA to increase the EE of massive MIMO uplink while limiting the EM exposure of users. In particularly, we investigate the optimization of the transmit covariance matrices and decoding order using statistical channel state information (CSI). The problem is formulated as non-convex mixed integer program, which is in general difficult to handle. We first propose a modified water-filling scheme to obtain the transmit covariance matrices with fixed decoding order. Then, a greedy approach is proposed to obtain the decoding permutation. Numerical results verify the effectiveness of the proposed EM exposure-aware EE maximization scheme for uplink RSMA.Comment: to appear in IEEE Journal on Selected Areas in Communication

Plasmonic Optical Nano-Antenna for Biomedical Applications

Plasmonics attract significant attention of the researchers due to Plasmon’s surpassing ability to match free space electromagnetic (EM) excitation into the nano-scale size and conduct the light-tissue interaction in this scale. Plasmonic nano-antennas (PNAs) is a coupling of EM waves into Localized Surface Plasmon Resonance (LSPR) which is considered as an interesting subject for theoretical and experimental study. This presents a new concept of the confinement of light in subwavelength scales with huge local fields which can generate very high near field intensities because of their LSPR. The generated field is invested in various applications that are depending on near field enhancement produced by plasmonic optical nano-antennas (PONAs) such as Surface-Enhanced Raman Spectroscopy (SERS), biosensing, spectral imaging and cancer treatment. Bowtie shape PNAs (PBNAs) can transfer the light field efficiently by converting the light from external space into a subwavelength spectral region with the improvement at an optical wavelength in a tiny area between its antenna arms. The local EM field production in a gap area is the main reason to suggest PBNAs shape if the frequency of the incident EM waves coincide the structural resonance peak so it is acting as a tunable hot spot

Dual antenna coupling manipulation for low SAR smartphone terminals in talk position

A rigorous analysis of the concept of coupling manipulation utilizing two antennas suited to modern smartphone devices in talk position for voice calls is presented. By using the optimum relative phase between the elements, they can substantially reduce the specific absorption rate (SAR) but still maintain efficiency due to the splitting of power between them and by exploiting a suitable level of inter element coupling. The same antenna elements can still be used for multiple input multiple output (MIMO) when not in talk position without heavily degrading their fundamental capacity limit but this is of secondary importance. The concept could be applied to frequency ranges used in mobile communications from 1.8 to 6 GHz where the ground plane has sufficient form factor. Extensive simulations using two planar inverted-F antennas (PIFAs) operating at 2.4 GHz are carried out to demonstrate conceptually how two antennas can be optimized to reduce SAR by over 50% compared to a single antenna element. SAR reduction is maintained regardless of the user’s head composition and how they are handling the device in talk position. Antenna prototypes are measured and compared to verify the capacity when the handset is used away from the body with two MIMO terminal antennas

Digital Background Self-Calibration Technique for Compensating Transition Offsets in Reference-less Flash ADCs

This Dissertation focusses on proving that background calibration using adaptive algorithms are low-cost, stable and effective methods for obtaining high accuracy in flash A/D converters. An integrated reference-less 3-bit flash ADC circuit has been successfully designed and taped out in UMC 180 nm CMOS technology in order to prove the efficiency of our proposed background calibration. References for ADC transitions have been virtually implemented built-in in the comparators dynamic-latch topology by a controlled mismatch added to each comparator input front-end. An external very simple DAC block (calibration bank) allows control the quantity of mismatch added in each comparator front-end and, therefore, compensate the offset of its effective transition with respect to the nominal value. In order to assist to the estimation of the offset of the prototype comparators, an auxiliary A/D converter with higher resolution and lower conversion speed than the flash ADC is used: a 6-bit capacitive-DAC SAR type. Special care in synchronization of analogue sampling instant in both ADCs has been taken into account. In this thesis, a criterion to identify the optimum parameters of the flash ADC design with adaptive background calibration has been set. With this criterion, the best choice for dynamic latch architecture, calibration bank resolution and flash ADC resolution are selected. The performance of the calibration algorithm have been tested, providing great programmability to the digital processor that implements the algorithm, allowing to choose the algorithm limits, accuracy and quantization errors in the arithmetic. Further, systematic controlled offset can be forced in the comparators of the flash ADC in order to have a more exhaustive test of calibration

AFCI Fuel Irradiation Test Plan, Test Specimens AFC-1Æ and AFC-1F

The U. S. Advanced Fuel Cycle Initiative (AFCI) seeks to develop and demonstrate the technologies needed to transmute the long-lived transuranic actinide isotopes contained in spent nuclear fuel into shorter-lived fission products, thereby dramatically decreasing the volume of material requiring disposition and the long-term radiotoxicity and heat load of high-level waste sent to a geologic repository (DOE, 2003). One important component of the technology development is actinide-bearing transmutation fuel forms containing plutonium, neptunium, americium (and possibly curium) isotopes. There are little irradiation performance data available on non-fertile fuel forms, which would maximize the destruction rate of plutonium, and low-fertile (i.e., uranium-bearing) fuel forms, which would support a sustainable nuclear energy option. Initial scoping level irradiation tests on a variety of candidate fuel forms are needed to establish a transmutation fuel form design and evaluate deployment of transmutation fuels