Search

Approximate computing has emerged as a design alternative to enhance design efficiency by capitalizing on the inherent error resilience observed in numerous applications. Various error-resilient and compute-intensive applications, such as signal, image and video processing, computer vision, and supervised machine learning, necessitate dedicated hardware accelerators for mean squared error estimation during runtime. In these application domains, using efficient arithmetic operators, particularly a squarer unit, represents one of the most effective strategies for low-power design. This work introduces an approximate Radix- 2 m squarer unit, denoted as AxRSU- 2 m . The proposed squarer unit employs m-bit approximate encoders to execute operations on m-bit data concurrently. The AxRSU- 2 m under consideration explores encoders with m equal to 2 (AxRSU-4), 3 (AxRSU-8), and 4 (AxRSU-16). These approximate encoders exhibit low complexity and diminish the necessary partial products operating on m bits simultaneously, thereby substantially enhancing energy efficiency and reducing circuit area in the AxRSU- 2 m . To illustrate the trade-off between error and quality in the AxRSU- 2 m , we apply it to an SSD (sum squared difference) hardware accelerator designed for video processing, with a square-accumulate serving as a case study. Our findings reveal a novel Pareto front, presenting eight optimal AxRSU- 2 m solutions that achieve accuracy levels ranging from 3.76 to 75.53%. These solutions yield energy savings ranging from 46.20 to 95.57% and circuit area reductions ranging from 37.68 to 66.73%. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the major citrus pest worldwide because it can transmit the bacteria associated with citrus greening disease (huanglongbing, HLB). The most common management strategy of this pest is chemical control, but this often results in pest resistance and threatens the sustainability of the citrus culture. There is therefore need for sustainable control strategies such as biological control. Previous experiments showed that the predatory mite Amblyseius herbicolus Chant (Acari: Phytoseiidae) is able to develop and reproduce on D. citri eggs. Here, we studied the population dynamics of this pest on plants with and without A. herbicolus on isolated orange jasmine plants, Murraya paniculata (L.) Jack (Rutaceae), an important host plant of the pest. Predatory mites were released 1 week before the release of D. citri and were provided with twines with pollen as oviposition sites and food source, respectively, to maintain populations of A. herbicolus in the absence of the pest. Densities of adults and nymphs of D. citri on plants with predators were about 85% lower than on plants without predators, showing that A. herbicolus is a potential biocontrol agent of D. citri. However, the stage structure of the D. citri populations at the end of the experiment did not differ significantly between control plants and plants with predators. This led us to investigate whether the predator attacked other stages besides eggs. Indeed, predators were able to feed and reproduce on first and second instar nymphs of D. citri, but not on instars 3–5. Concluding, the release of A. herbicolus with alternative food and oviposition sites can reduce infestations of D. citri. We suggest that field experiments should be done in areas where HLB occurs to test whether releases of this predator limit the spread of this devastating disease. [ABSTRACT FROM AUTHOR]

Multipliers are demanded in a variety of applications. They consume higher power than other blocks. On the other hand, squarer units are less complex than a general-purpose multiplier, with wide use in cryptography, image processing, and video coding. This paper presents a new radix-2m squarer unit. It uses the essential sum trees to avoid redundant operations. Omitting some duplicate multiplications simplifies the final VLSI architecture. This work uses the radix-2m squarer units with m equal to 2 (radix-4), 3 (radix-8) and 4 (radix-16). We evaluate the proposed squarer units using high-efficiency video coding (HEVC) and cryptography algorithms for a range of bits. For performance results, the architectures use random input vectors. The results show that radix-4 and radix-8 units are more area and power efficient than radix-16 units. Moreover, the high energy savings of our proposed radix-4 and radix-8 units are preserved in the case studies addressed, compared to squarer units from the literature. Particularly, we show that radix-4 and radix-8 provide more energy savings in computing sum of squared differences (SSD). Furthermore, radix-4 and radix-8 squarer units are also efficient in the Montgomery-ladder architecture, reducing energy by 58.76% (radix-8) and 63.39% (radix-4) compared to the multiplier automatically selected by the logic synthesis tool. [ABSTRACT FROM AUTHOR]

This article navigates ruptures and transformations in the processes of resistance performed by Iranian workers between two key events of the history of contemporary Iran: the 1979 Revolution and the 2009 Green Movement. It explores how labor activism emerged in the Islamic Republic, and illustrates how it managed to survive. Drawing from the concepts of resistance, collective awareness and counter-conduct as its theoretical basis – between Antonio Gramsci and Michel Foucault – the article details the changing strategies that workers adopted over time and space to cope with the absence of trade unions, monitoring activities, and repression in the workplace. It demonstrates that workers' agency was never fully blocked by the Islamic Republic. However, it tests the limits imposed by the social context to discourage activism, beyond state coercive measures and policies. [ABSTRACT FROM AUTHOR]

The experiments reported in this research communication analysed the presence of methicillin-resistant Staphylococcus aureus (MRSA) in 112 samples of 'coalho' cheese, from 56 dairy producing farms in 28 cities in all mesoregions of the State of Ceará, Brazil. To assess antimicrobial resistance we also examined the presence of genes encoding enterotoxins and toxic shock syndrome toxin, as well as the presence of the blaZ gene for β-lactamases, and resistance to oxacillin. The research found 69 isolates of S. aureus, of which 13.04% had the mecA gene encoding the penicillin-binding protein, which confers resistance to methicillin, in cheese samples from 6 different cities. This included the state capital, Fortaleza, which had the largest prevalence (23.19%) of mecA positive isolates. It was also found that 55.07% of the isolates of S. aureus had the blaZ gene, and 7.25% demonstrated resistance to oxacillin in the plate disc diffusion tests. We did not show the presence of isolates carrying toxigenic genes. The findings suggest that strict supervision of production processes in the dairy industry is necessary in all production scale processes, thus preventing contamination and possible problems for consumers. [ABSTRACT FROM AUTHOR]

This brief proposes an energy-efficient Haar wavelet transform for respiratory signal processing. We analyze and develop a Haar level 5 (Haar-5) transform architecture for separating the frequency bands of respiratory signals. The fixed-point Haar-5 transform herein proposed employs multi-level $M=1$ , $M=2$ , and $M=3$ Haar transforms for the composition of five resolution levels. The architectures were described in VHDL and synthesized in hardware targeting a 65nm CMOS standard cell library. Our investigation results show that most area- and energy-efficient Haar architecture (i.e., version H-IV) employs one $M=1$ block and two $M=2$ blocks. Hardware synthesis results show that the H-IV architecture proposal saves 38.19% of circuit area and 38.26% of power dissipation and energy per operation, compared among the other architectures herein investigated. Our H-IV hardware architecture proposal shows more than 1150 times of energy reduction than state of the art. [ABSTRACT FROM AUTHOR]

Predatory mites of the Phytoseiidae family are important biological control agents. Many species of this family are omnivores, i.e., besides on prey, they can feed on plant resources such as nectar and pollen. It has been shown that the addition of alternative food for predators to a crop enhances biological control. However, factors such as food availability and quality can also affect interactions such as cannibalism, and thus influence biological control. We investigated the role of quality of the alternative food in the tendency of Amblyseius herbicolus to engage in cannibalism, a common ecological interaction in many phytoseiid mite species. Cannibalism on eggs by A. herbicolus was significantly reduced in the presence of high-quality food (cattail pollen) compared to egg cannibalism without alternative food, whereas this was not the case in the presence of low-quality food (cotton pollen). This suggests that cattail pollen is a high-quality alternative food, not only because it results in increased development and reproduction of predators, but also because it can minimize cannibalism. [ABSTRACT FROM AUTHOR]

Pranayama refers to a set of yoga breathing exercises. Recent evidence suggests that the practice of pranayama has positive effects on measures of clinical stress and anxiety. This study explored the impact of a Bhastrika pranayama training program on emotion processing, anxiety, and affect. We used a randomized controlled trial design with thirty healthy young adults assessed at baseline and after 4 weeks of pranayama practices. Two functional magnetic resonance imaging (MRI) protocols were used both at baseline and post-intervention: an emotion task as well as a resting-state acquisition. Our results suggest that pranayama significantly decreased states of anxiety and negative affect. The practice of pranayama also modulated the activity of brain regions involved in emotional processing, particularly the amygdala, anterior cingulate, anterior insula, and prefrontal cortex. Resting-state functional MRI (fMRI) showed significantly reduced functional connectivity involving the anterior insula and lateral portions of the prefrontal cortex. Correlation analysis revealed that changes in connectivity between the ventrolateral prefrontal cortex and the right anterior insula were associated with changes in anxiety. Although it should be noted that these analyses were preliminary and exploratory, it provides the first evidence that 4 weeks of B. pranayama significantly reduce the levels of anxiety and negative affect, and that these changes are associated with the modulation of activity and connectivity in brain areas involved in emotion processing, attention, and awareness. The study was registered at https://www.ensaiosclinicos.gov.br/rg/RBR-2gv5c2/(RBR-2gv5c2). [ABSTRACT FROM AUTHOR]

AUTH The authors report on pulsed laser powder bed fusion fabrication of nitinol (NiTi) shape memory materials. The authors first performed single-track laser parameter sweeps to assess melt pool stability and determine energy parameters and hatch spacing for larger builds. The authors then assessed the melt pool chemistry as a function of laser energy density and build plate composition. Brittle intermetallics were found to form at the part/build plate interface for both N200 and Ti-6-4 substrates. The intermetallic formation was reduced by building on a 50Ni–50Ti substrate, but delamination still occurred due to thermal stresses upon cooling. The authors were able to overcome delamination on all substrates and fabricate macroscopic parts by building a lattice support structure, which is both compliant and controls heat transfer into the build plate. This approach will enable scalable fabrication of complex NiTi parts. [ABSTRACT FROM AUTHOR]

Scalable, bottom‐up chemical synthesis and electrospinning of novel Cl‐substituted poly(para‐phenylene terephthalamide) (PPTA) nanofibers are herein reported. To achieve Cl‐PPTA nanofibers, the chemical reaction between the monomers was precisely controlled, and dissolution of the polymer into solvent was tailored to enable anisotropic solution formation and sufficient entanglement molecular weight. Electrospinning processing parameters were studied to understand their effects on fiber formation and mat morphology and then optimized to yield consistently high quality fibers. Importantly, the control of relative humidity during the fiber formation process was found to be critical, likely because water promotes hydrogen bond formation between the PPTA chains. The fiber and mat morphologies resulting from different combinations of chemistry and spinning conditions were observed using scanning electron microscopy, and observations were used as inputs to the optimization process. Tensile properties of single Cl‐PPTA nanofibers were characterized for the first time using a nanomanipulator mounted inside a scanning electron microscope (SEM), and fiber moduli measuring up to 70 GPa, and strengths exceeding 1 GPa were achieved. Given the excellent mechanical properties measured for the nanofibers, this chemical synthesis procedure and electrospinning protocol appear to be a promising route for producing a new class of nanofibers with ultrahigh strength and stiffness. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 563–573 [ABSTRACT FROM AUTHOR]

Background: Recent open-label trials show that psychedelics, such as ayahuasca, hold promise as fast-onset antidepressants in treatment-resistant depression. Methods: To test the antidepressant effects of ayahuasca, we conducted a parallel-arm, double-blind randomized placebo-controlled trial in 29 patients with treatment-resistant depression. Patients received a single dose of either ayahuasca or placebo. We assessed changes in depression severity with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hamilton Depression Rating scale at baseline, and at 1 (D1), 2 (D2), and 7 (D7) days after dosing. Results: We observed significant antidepressant effects of ayahuasca when compared with placebo at all-time points. MADRS scores were significantly lower in the ayahuasca group compared with placebo at D1 and D2 (p = 0.04), and at D7 (p < 0.0001). Between-group effect sizes increased from D1 to D7 (D1: Cohen's d = 0.84; D2: Cohen's d = 0.84; D7: Cohen's d = 1.49). Response rates were high for both groups at D1 and D2, and significantly higher in the ayahuasca group at D7 (64% v. 27%; p = 0.04). Remission rate showed a trend toward significance at D7 (36% v. 7%, p = 0.054). Conclusions: To our knowledge, this is the first controlled trial to test a psychedelic substance in treatment-resistant depression. Overall, this study brings new evidence supporting the safety and therapeutic value of ayahuasca, dosed within an appropriate setting, to help treat depression. This study is registered at http://clinicaltrials.gov (NCT02914769). [ABSTRACT FROM AUTHOR]

This paper explores the transformations of the Islamic Republic of Iran's dominant narratives on labor between 1979 and 2009. By analyzing official May Day speeches of this period, it navigates multiple constructions of workers' roles, which were systematically propagated by the IRI's Supreme Leader and president over time. The analysis relies on the following primary sources: from the 1979 May Day sermon, pronounced by Ruhollah Khomeini, to the 2009 speech given by Mahmoud Ahmadinejad, together with messages sent by Ali Khamenei, Hashemi Rafsanjani and Mohammad Khatami. Showing how workers' role—understood as a collective and distinct group—was gradually minimized, this paper argues that a bottom-up cleaning up process slowly purified May Day. In fact, the IRI progressively neglected workers as (revolutionary) social actors and interlocutors, as it stopped talking to masses and started speaking to middle classes. [ABSTRACT FROM AUTHOR]

Background: Mirror therapy (MT) is becoming an alternative rehabilitation strategy for various conditions, including stroke. Although recent studies suggest the positive benefit of MT in chronic stroke motor recovery, little is known about its neural mechanisms. Purpose: To identify functional brain changes induced by a single MT intervention in ischemic stroke survivors, assessed by both transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI). Materials and methods: TMS and fMRI were used to investigate 15 stroke survivors immediately before and after a single 30-min MT session. Results: We found statistically significant increase in post-MT motor evoked potential (MEP) amplitude (increased excitability) from the affected primary motor cortex (M1), when compared to pre-MT MEP. Post-MT fMRI maps were associated with a more organized and constrained pattern, with a more focal M1 activity within the affected hemisphere after MT, limited to the cortical area of hand representation. Furthermore, we find a change in the balance of M1 activity toward the affected hemisphere. In addition, significant correlation was found between decreased fMRI β-values and increased MEP amplitude post-MT, in the affected hemisphere. Conclusion: Our study suggests that a single MT intervention in stroke survivors is related to increased MEP of the affected limb, and a more constrained activity of the affected M1, as if activity had become more constrained and limited to the affected hemisphere. [ABSTRACT FROM AUTHOR]

ABSTRACT The synthesis and electrospinning of novel N-substituted aramid nanofibers (ANFs) prepared from basic dispersions of commercial microscale Kevlar fibers are herein reported. The functionalized ANFs were characterized via Fourier transform infrared spectroscopy, 13C solid-state nuclear magnetic resonance spectroscopy, and X-ray diffraction to confirm proper N-substitution of the side groups and to determine changes to the polymer crystallinity and stability. These analyses suggested that the electrospun ANFs consisted of numerous crystalline domains in the transverse fiber direction with large amorphous regions that were void of defects commonly found in commercial Kevlar fibers. A semi-empirical study of the variations in the solubility parameter due to various side chain moieties was conducted to facilitate solvent selection and to elucidate the enhanced solubility effects with selected organic solvents. These initial findings suggest a promising route for obtaining a new class of nanofibers with ultrahigh strength and stiffness. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44082. [ABSTRACT FROM AUTHOR]

Prompt emergency treatment for ocular injury, particularly in a battlefield setting, is essential to preserve vision, reduce pain, and prevent secondary infection. A bandage contact lens that could be applied in the field, at the time of injury, would protect the injured ocular surface until hospital treatment is available. Cellulose, a natural polymer, is widely used in biomedical applications including bandage materials. Hydrogels synthesized from different cellulose sources, such as plants, cotton, and bacteria, can have the optical transparency and mechanical strength of contact lenses, by tailoring synthesis parameters. Thus, we optimized the fabrication of cellulose-based hydrogels and evaluated their in vivo biocompatibility and related physical properties. Our data demonstrate that along with tailorable physical properties, our novel cellulose-based hydrogels could be made with contact lens geometry, exhibit no significant signs of material toxicity after 22 days of in vivo testing, and show significant promise for use as a corneal bandage immediately following ocular trauma. [ABSTRACT FROM AUTHOR]

Motor rehabilitation of stroke survivors may include functional and/or nonfunctional strategy. The present study aimed to compare the effect of these two rehabilitation strategies by means of clinical scales and functional Magnetic Resonance Imaging (fMRI). Twelve hemiparetic chronic stroke patients were selected. Patients were randomly assigned a nonfunctional (NFS) or functional (FS) rehabilitation scheme. Clinical scales (Fugl-Meyer, ARA test, and modified Barthel) and fMRI were applied at four moments: before rehabilitation (P1) and immediately after (P2), 1 month after (P3), and three months after (P4) the end of rehabilitation. The NFS group improved significantly and exclusively their Fugl-Meyer scores at P2, P3, and P4, when compared to P1. On the other hand, the FS group increased significantly in Fugl-Meyer at P2, when compared to P1, and also in their ARA and Barthel scores. fMRI inspection at the individual level revealed that both rehabilitation schemes most often led to decreased activation sparseness, decreased activity of contralesional M1, increased asymmetry of M1 activity to the ipsilesional side, decreased perilesional activity, and decreased SMA activity. Increased M1 asymmetry with rehabilitation was also confirmed by Lateralization Indexes. Our clinical analysis revealed subtle differences between FS and NFS. [ABSTRACT FROM AUTHOR]

Purpose This study was performed to evaluate the potential of a collagen-based membrane, collagen vitrigel ( CV), for reconstructing corneal epithelium in the stromal wound and limbal stem cell deficiency ( LSCD) models. Methods Three groups of rabbits were used in the stromal wound model: CV affixed using fibrin glue ( CV + FG group, n = 9), fibrin glue only ( FG group, n = 3) and an untreated control group ( n = 3). In the LSCD model, one group received CV containing human limbal epithelial cells ( CV + hLEC group, n = 2) and the other was an untreated control ( n = 1). Gross observation, including fluorescent staining, pathological examination, immunohistochemistry and electron microscopy, was used to evaluate the effect of CV on the corneal epithelium. Results In the stromal wound model, fluorescent staining showed that epithelial reconstruction occurred as rapidly in the CV + FG group as it did in the control group. The pathological examination proved that the CV supported a healthy corneal epithelium in the CV + FG group, whereas FG led to hypertrophy and inappropriate differentiation of corneal epithelium in the FG group. In the LSCD model, the corneas in the CV + h LEC group showed sustained tissue transparency with good epithelialization, low inflammatory response and reduced neovascularization. However, the control cornea was translucent and showed high amounts of inflammation and neovascularization. Conclusion We have demonstrated that CV supports corneal epithelial differentiation and prevents epithelial hypertrophy, in addition to serving as a scaffold for h LEC transplantation, without complications. [ABSTRACT FROM AUTHOR]

Extensive agriculture application of rare earth elements (REEs) in Far East countries might cause spreading of these metals in aquatic and terrestrial ecosystems, thus inducing a growing concern about their environmental impact. In this work the effects of a mix of different REE nitrate (RE) and of lanthanum nitrate (LA) on catalase and antioxidant systems involved in the ascorbate–glutathione cycle were investigated in common duckweed Lemna minor L. The results indicated that L. minor shows an overall good tolerance to the presence of REEs in the media. Treatments at concentrations up to 5 mM RE and 5 mM LA did not cause either visible symptoms on plants or significant effects on reactive oxygen species (ROS) production, chlorophyll content, and lipid peroxidation. Toxic effects were observed after 5 days of exposition to 10 mM RE and 10 mM LA. A remarkable increase in glutathione content as well as in enzymatic antioxidants was observed before the appearance of the stress symptoms in treated plants. Duckweed plants pretreated with RE and LA were also exposed to chilling stress to verify whether antioxidants variations induced by RE and LA improve plant resistance to the chilling stress. In pretreated plants, a decrease in ascorbate and glutathione redox state and in chlorophyll content and an increase in lipid peroxidation and ROS production levels were observed. The use of antioxidant levels as a stress marker for monitoring REE toxicity in aquatic ecosystems by means of common duckweed is discussed. [ABSTRACT FROM AUTHOR]

We report the synthesis, characterization, and optical properties of high-temperature stable lanthanide-doped luminescent zirconia nanoparticles via a novel method using carbon black as template. Dopant concentrations were varied from 1 to 5% of Er3+ or Nd3+ and annealing temperatures were varied from 650 to 1100 °C. The effects of the dopant concentration on crystal structure and emission properties were evaluated using x-ray powder diffraction and fluorescence spectroscopy, respectively. The lanthanide cations were found to stabilize the tetragonal phase of zirconia over the monoclinic phase as dopant concentration was increased to 5%. Increasing the annealing temperature to 1100 °C had the opposite effect and was found to stabilize the monoclinic phase of zirconia. The luminescence intensity of the Nd-doped zirconia was enhanced by two orders of magnitude over the undoped or Er-doped zirconia. In all cases, the luminescence spectra revealed increasing intensity with increasing annealing temperature. Zirconia luminescence at near-infrared wavelengths is likely caused by oxygen vacancies. This work demonstrates that the spectral signatures of fluorescent zirconia nanoparticles can be modified with small lanthanide dopant concentration. These particles will have utility in fluorescent sensors and tags, as well as new in refractory materials. [ABSTRACT FROM AUTHOR]