149 research outputs found
ATTACKING NEURAL NETWORKS WITH HIGH ENTROPY INPUT SAMPLING
Deep learning is becoming a technology central to the safety and accuracy of many types of systems. Unfortunately, attackers can create adversarial examples that manipulate Deep Neural Networks (DNN) into making incorrect predictions by carefully crafting perturbations that, to humans, look indistinguishable from examples the DNN would classify correctly. Research shows that adversarial examples exist near the decision boundary. Decision-based attacks are designed to find adversarial examples by traversing the data manifold toward the decision boundary using iterative sampling without any knowledge of the model parameters or gradients. In this sense, decision-based attacks are very important, as they apply to many real-world attack scenarios. We propose a new decision-based attack, High Entropy Input Sampling (HEIS), that iteratively steps toward the decision boundary by using entropy over class predictions as a heuristic to find adversarial examples without any knowledge of the model gradients. Using HEIS, we were able to produce adversarial examples that reduced the accuracy of a CIFAR-10 DNN from 91% to 11% for epsilon=0.2 and reduced the accuracy of ResNet50, an ImageNet DNN, from 81% to 22% for epsilon=0.4. Furthermore, we discovered that the adversarial examples are highly transferable to other models, causing dramatic drops in accuracy among all models tested. Finally, we use HEIS to break three state-of-the-art neural network defenses.Lieutenant, United States NavyApproved for public release. Distribution is unlimited
Comparison of Monomethylhydrazine/Hydroxypropylcellulose and Hydrocarbon/Silica Gels
Experimental studies have been performed to investigate rheology and droplet burning with different types of gelled propellants. Monomethylhydrazine has been gelled with organic hydroxypropylcellulose. JP-8 and RP-1 hydrocarbon gels have been produced with inorganic fumed silica particles. Rheological characterization showed the differences in terms of viscosity and yield stress behavior due to different types of gelling agents. Herschel-Bulkley and Carreau-Yasuda models have been used to characterize the gels with inorganic and organic gelling agents, respectively. First experiments with the Monomethylhydrazine/hydroxypropylcellulose gels showed a typical swelling process during combustion with a flexible viscous droplet surface. Contrary to that, the hydrocarbon/silica gels burned while a rigid silica structure was built, which remained unburned. Burning drop measurements have been compared to the d^2-squared law
The universal red-giant oscillation pattern; an automated determination with CoRoT data
The CoRoT and Kepler satellites have provided thousands of red-giant
oscillation spectra. The analysis of these spectra requires efficient methods
for identifying all eigenmode parameters. The assumption of new scaling laws
allows us to construct a theoretical oscillation pattern. We then obtain a
highly precise determination of the large separation by correlating the
observed patterns with this reference. We demonstrate that this pattern is
universal and are able to unambiguously assign the eigenmode radial orders and
angular degrees. This solves one of the current outstanding problems of
asteroseismology hence allowing precise theoretical investigation of red-giant
interiors.Comment: Accepted in A&A letter
Micro-Hall Magnetometry Studies of Thermally Assisted and Pure Quantum Tunneling in Single Molecule Magnet Mn12-Acetate
We have studied the crossover between thermally assisted and pure quantum
tunneling in single crystals of high spin (S=10) uniaxial single molecule
magnet Mn12-acetate using micro-Hall effect magnetometry. Magnetic hysteresis
experiments have been used toinvestigate the energy levels that determine the
magnetization reversal as a function of magnetic field and temperature. These
experiments demonstrate that the crossover occurs in a narrow (~0.1 K) or broad
(~1 K) temperature interval depending on the magnitude and direction of the
applied field. For low external fields applied parallel to the easy axis, the
energy levels that dominate the tunneling shift abruptly with temperature. In
the presence of a transverse field and/or large longitudinal field these energy
levels change with temperature more gradually. A comparison of our experimental
results with model calculations of this crossover suggest that there are
additional mechanisms that enhance the tunneling rate of low lying energy
levels and broaden the crossover for small transverse fields.Comment: 5 pages, 5 figure
Sex-related differences in morphological, physiological, and ultrastructural responses of Populus cathayana to chilling
Low temperature is one of the abiotic factors limiting plant growth and productivity. Yet, knowledge about sex-related responses to low temperature is very limited. In our study, the effects of low, non-freezing temperature on morphological, physiological, and ultrastructural traits of leaves in Populus cathayana Rehd. males and females were investigated. The results showed that 4 °C temperature caused a chilling stress, and females suffered from greater negative effects than did males. At the early growth stage of development, chilling (4 °C) significantly inhibited plant growth, decreased net photosynthesis rate (Pn), stomatal conductance (gs), transpiration (E), and chlorophyll pigments (Chl), and increased intercellular CO2 concentration (Ci), chlorophyll a/b (Chl a/b), proline, soluble sugar and H2O2 contents, and ascorbate peroxidase (APX) activity in both sexes, whereas peroxidase (POD) and glutathione reductase (GR) activities decreased and thiobarbituric acid reactive substance (TBARS) content increased only in females. Chilling stress also caused chloroplast changes and an accumulation of numerous plastoglobules and small vesicles in both sexes. However, disintegrated chloroplasts and numerous tilted grana stacks were only found in chilling-stressed females. Under chilling stress, males showed higher Chl and soluble sugar contents, and higher superoxide dismutase (SOD), POD, and GR activities than did females. In addition, males exhibited a better chloroplast structure and more intact plasma membranes than did females under chilling stress. These results suggest that sexually different responses to chilling are significant and males possess a better self-protection mechanism than do females in P. cathayana
Tracking the Expression of Excitatory and Inhibitory Neurotransmission-Related Proteins and Neuroplasticity Markers after Noise Induced Hearing Loss
Excessive exposure to loud noise can damage the cochlea and create a hearing loss. These pathologies coincide with a range of CNS changes including reorganisation of frequency representation, alterations in the pattern of spontaneous activity and changed expression of excitatory and inhibitory neurotransmitters. Moreover, damage to the cochlea is often accompanied by acoustic disorders such as hyperacusis and tinnitus, suggesting that one or more of these neuronal changes may be involved in these disorders, although the mechanisms remain unknown. We tested the hypothesis that excessive noise exposure increases expression of markers of excitation and plasticity, and decreases expression of inhibitory markers over a 32-day recovery period. Adult rats (n = 25) were monaurally exposed to a loud noise (16 kHz, 1/10th octave band pass (115 dB SPL)) for 1-hour, or left as non-exposed controls (n = 5). Animals were euthanased at either 0, 4, 8, 16 or 32 days following acoustic trauma. We used Western Blots to quantify protein levels of GABAA receptor subunit α1 (GABAAα1), Glutamic-Acid Decarboxylase-67 (GAD-67), N-Methyl-D-Aspartate receptor subunit 2A (NR2A), Calbindin (Calb1) and Growth Associated Protein 43 (GAP-43) in the Auditory Cortex (AC), Inferior Colliculus (IC) and Dorsal Cochlear Nucleus (DCN). Compared to sham-exposed controls, noise-exposed animals had significantly (p<0.05): lower levels of GABAAα1 in the contralateral AC at day-16 and day-32, lower levels of GAD-67 in the ipsilateral DCN at day-4, lower levels of Calb1 in the ipsilateral DCN at day-0, lower levels of GABAAα1 in the ipsilateral AC at day-4 and day-32. GAP-43 was reduced in the ipsilateral AC for the duration of the experiment. These complex fluctuations in protein expression suggests that for at least a month following acoustic trauma the auditory system is adapting to a new pattern of sensory input
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Care planning for consumers on community treatment orders: an integrative literature review
Background
Case management is the established model for care provision in mental health and is delivered within current care philosophies of person-centred and recovery-oriented care. The fact that people with a mental illness may be forced to receive care and treatment in the community poses challenges for clinicians aiming to engage in approaches that promote shared decision-making and self-determination. This review sought to gain an in-depth understanding of stakeholders’ perspectives and experiences of care planning for consumers’ on CTOs.
Methods
An integrative review method allowed for inclusion of a broad range of studies from diverse empirical sources. Systematic searches were conducted across six databases. Following appraisal, findings from included papers were coded into groups and presented against a framework of case management.
Results
Forty-eight papers were included in the review. Empirical studies came from seven countries, with the majority reporting on qualitative methods. Many similarities were reported across studies. Positive gains from CTOs were usually associated with the nature of support received, highlighting the importance of the therapeutic relationship in care planning. Key gaps in care planning included a lack of connection between CTO, treatment and consumer goals and lack of implementation of focussed interventions.
Conclusions
Current case management processes could be better utilised for consumers on CTOs, with exploration of how this could be achieved warranted. Workers need to be sensitive to the ‘control and care’ dynamic in the care planning relationship, with person-centred approaches requiring core and advanced practitioner and communication skills, including empathy and trust
Subcellular compartmentation of glutathione in dicotyledonous plants
This study describes the subcellular distribution of glutathione in roots and leaves of different plant species (Arabidopsis, Cucurbita, and Nicotiana). Glutathione is an important antioxidant and redox buffer which is involved in many metabolic processes including plant defense. Thus information on the subcellular distribution in these model plants especially during stress situations provides a deeper insight into compartment specific defense reactions and reflects the occurrence of compartment specific oxidative stress. With immunogold cytochemistry and computer-supported transmission electron microscopy glutathione could be localized in highest contents in mitochondria, followed by nuclei, peroxisomes, the cytosol, and plastids. Within chloroplasts and mitochondria, glutathione was restricted to the stroma and matrix, respectively, and did not occur in the lumen of cristae and thylakoids. Glutathione was also found at the membrane and in the lumen of the endoplasmic reticulum. It was also associated with the trans and cis side of dictyosomes. None or only very little glutathione was detected in vacuoles and the apoplast of mesophyll and root cells. Additionally, glutathione was found in all cell compartments of phloem vessels, vascular parenchyma cells (including vacuoles) but was absent in xylem vessels. The specificity of this method was supported by the reduction of glutathione labeling in all cell compartments (up to 98%) of the glutathione-deficient Arabidopsis thaliana rml1 mutant. Additionally, we found a similar distribution of glutathione in samples after conventional fixation and rapid microwave-supported fixation. Thus, indicating that a redistribution of glutathione does not occur during sample preparation. Summing up, this study gives a detailed insight into the subcellular distribution of glutathione in plants and presents solid evidence for the accuracy and specificity of the applied method
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