Comparison of Computational-Model and Experimental-Example Trained Neural Networks for Processing Speckled Fringe Patterns

The responses of artificial neural networks to experimental and model-generated inputs are compared for detection of damage in twisted fan blades using electronic holography. The training-set inputs, for this work, are experimentally generated characteristic patterns of the vibrating blades. The outputs are damage-flag indicators or second derivatives of the sensitivity-vector-projected displacement vectors from a finite element model. Artificial neural networks have been trained in the past with computational-model-generated training sets. This approach avoids the difficult inverse calculations traditionally used to compare interference fringes with the models. But the high modeling standards are hard to achieve, even with fan-blade finite-element models

An Examination of Post-Traumatic Stress Symptoms and Aggression Among Children with a History of Adverse Childhood Experiences

Childhood aggression is associated with many deleterious outcomes and is a common reason for psychiatric referral (Card and Little 2006; Gurnani, Ivanov, and Newcorn 2016). One factor associated with childhood aggression is Adverse Childhood Experiences (ACEs; Felitti et al. 1998). However, existing research remains equivocal on which characteristics of ACEs (e.g., cumulative impact, typology, etc.) are significantly elated to aggression, especially when considering differential effects of ACEs on proactive aggression (PA) and reactive aggression (RA; Dodge and Coie, 1987). Post-traumatic stress symptoms (PTSS) are a common negative sequalae of ACEs and are characterized by disruptions in several cognitive, emotional, and behavioral processes similar to those associated with both RA and PA (e.g., Marsee 2008). As such, the examination of PTSS as an underlying mechanism of influence on the relation between ACEs, PA, and RA is warranted. The present study fills several gaps in the literature by examining ACE characteristics that might be related to PTSS, PA, and RA while also examining direct and indirect effects on the relation between ACEs, PTSS and PA and RA. Results indicated the type of ACE, specifically child maltreatment ACEs (CM-ACEs), was most strongly related to all outcome variables. Therefore, CM-ACEs were included in a path analysis with PTSS, PA, and RA. Results indicated a significant indirect effect for PTSS on the relation between CM-ACEs and RA (β = .18, p \u3c .01) but not PA. Findings have several implications for future research and clinical practice, especially for children with an extensive history of CM-ACEs

Pathways from Child Maltreatment to Proactive and Reactive Aggression: The Role of Post-Traumatic Stress Symptom Clusters

Objective: Childhood aggression is related to a myriad of negative concurrent and long-term outcomes. To mitigate the risks associated with childhood aggression, it is important to understand risk factors that might predispose one to aggressive behaviors. One risk factor commonly associated with aggression is the experience of child maltreatment. A common outcome associated with child maltreatment is the development of post-traumatic stress symptoms (PTSS). Several prevailing theoretical models of both post-traumatic stress and aggression indicate that these constructs have similar underlying cognitive, behavioral, and emotional mechanisms. Therefore, the present study examined the relations between and among child maltreatment, PTSS clusters, and proactive and reactive aggression in children. Method: Children between the ages of 6 and 14 who were enrolled in a residential treatment program completed self-report measures to evaluate variables of interest. These variables were included as multiple outcomes in a path analysis model in which individual PTSS clusters were examined as potential multiple mediators of the relations between child maltreatment and proactive and reactive aggression. Results: Direct effects of child maltreatment and PTSS clusters on aggression were observed. Significant indirect effects of the intrusion PTSS cluster on the relation between child maltreatment and reactive aggression was found. Conclusions: Findings suggest that symptoms associated with these specific PTSS clusters might help explain the relation between child maltreatment and reactive aggression and therefore present important implications for clinical practice and future research

Development of frequency-agile high-repetition-rate CO{sub 2} DIAL systems for long range chemical remote sensing

Issues related to the development of direct detection, long-range CO{sub 2} DIAL systems for chemical detection and identification are presented and discussed including: data handling and display techniques for large, multi-{lambda} data sets, turbulence effects, slant path propagation, and speckle averaging. Data examples from various field campaigns and CO{sub 2} lidar platforms are used to illustrate the issues

Theory of vortex excitation imaging via an NMR relaxation measurement

The temperature dependence of the site-dependent nuclear spin relaxation time T_1 around vortices is studied in s-wave and d-wave superconductors.Reflecting low energy electronic excitations associated with the vortex core, temperature dependences deviate from those of the zero-field case, and T_1 becomes faster with approaching the vortex core. In the core region, T_1^{-1} has a new peak below T_c. The NMR study by the resonance field dependence may be a new method to prove the spatial resolved vortex core structure in various superconductors.Comment: 5 pages, 3 figure

Nonthermal Emission from a Supernova Remnant in a Molecular Cloud

In evolved supernova remnants (SNRs) interacting with molecular clouds, such as IC 443, W44, and 3C391, a highly inhomogeneous structure consisting of a forward shock of moderate Mach number, a cooling layer, a dense radiative shell and an interior region filled with hot tenuous plasma is expected. We present a kinetic model of nonthermal electron injection, acceleration and propagation in that environment and find that these SNRs are efficient electron accelerators and sources of hard X- and gamma-ray emission. The energy spectrum of the nonthermal electrons is shaped by the joint action of first and second order Fermi acceleration in a turbulent plasma with substantial Coulomb losses. Bremsstrahlung, synchrotron, and inverse Compton radiation of the nonthermal electrons produce multiwavelength photon spectra in quantitative agreement with the radio and the hard emission observed by ASCA and EGRET from IC 443. We distinguish interclump shock wave emission from molecular clump shock wave emission accounting for a complex structure of molecular cloud. Spatially resolved X- and gamma- ray spectra from the supernova remnants IC 443, W44, and 3C391 as might be observed with BeppoSAX, Chandra XRO, XMM, INTEGRAL and GLAST would distinguish the contribution of the energetic lepton component to the gamma-rays observed by EGRET.Comment: 14 pages, 4 figure, Astrophysical Journal, v.538, 2000 (in press

Site-selective nuclear magnetic relaxation time in a superconducting vortex state

The temperature and field dependences of the site-selective nuclear spin relaxation time T_1 around vortices are studied comparatively both for s-wave and d-wave superconductors, based on the microscopic Bogoliubov-de Gennes theory. Reflecting low energy electronic excitations associated with the vortex core, the site selective temperature dependences deviate from those of the zero-field case, and T_1 becomes faster with approaching the vortex core. In the core region, T_1^{-1} has a new peak below the superconducting transition temperature T_c. The field dependence of the overall T_1(T) behaviors for s-wave and d-wave superconductors is investigated and analyzed in terms of the local density of states. The NMR study by the resonance field dependence may be a new method to probe the spatial resolved vortex core structure in various conventional and unconventional superconductors.Comment: 14Pages, 26 figures, revte

A magnetization and 11^{11}B NMR study of Mg1−x_{1-x}Alx_xB2_2 superconductors

We demonstrate for the first time the magnetic field distribution of the pure vortex state in lightly doped Mg$_{1-x}$Al$_x$B$_2$ ($x\leq 0.025$) powder samples, by using $^{11}$B NMR in magnetic fields of 23.5 and 47 kOe. The magnetic field distribution at T=5 K is Al-doping dependent, revealing a considerable decrease of anisotropy in respect to pure MgB$_2$. This result correlates nicely with magnetization measurements and is consistent with $\sigma$-band hole driven superconductivity for MgB$_2$

11^{11}B NMR study of pure and lightly carbon doped MgB2_2 superconductors

We report a $^{11}$B NMR line shape and spin-lattice relaxation rate ($1/(T_1T)$) study of pure and lightly carbon doped MgB$_{2-x}$C$_{x}$ for $x=0$, 0.02, and 0.04, in the vortex state and in magnetic field of 23.5 kOe. We show that while pure MgB$_2$ exhibits the magnetic field distribution from superposition of the normal and the Abrikosov state, slight replacement of boron with carbon unveils the magnetic field distribution of the pure Abrikosov state. This indicates a considerable increase of $H_{c2}^c$ with carbon doping with respect to pure MgB$_2$. The spin-lattice relaxation rate $1/(T_1T)$ demonstrates clearly the presence of a coherence peak right below $T_c$ in pure MgB$_2$, followed by a typical BCS decrease on cooling. However, at temperatures lower than $\approx 10$K strong deviation from the BCS behavior is observed, probably from residual contribution of the vortex dynamics. In the carbon doped systems both the coherence peak and the BCS temperature dependence of $1/(T_1T)$ weaken, an effect attributed to the gradual shrinking of the $\sigma$ hole cylinders of the Fermi surface with electron doping.Comment: 8 pages, 6 figures, submitted to Phys. Rev.