Marital distress and mental health care service utilization.

Objective: This study was designed to evaluate the association between marital distress and mental health service utilization in a population-based sample of men and women (N = 1,601). Method: The association between marital distress and mental health care service utilization was evaluated for overall mental health service utilization and for specific sectors of treatment providers, including psychiatrist, other mental health provider, other medical provider, and religious services provider. Interviews were used to assess past-year service utilization and presence of anxiety, mood, and substance use disorders. Results: Approximately 12% of married individuals sought help for problems with their emotions, nerves, or substance use during the 12 months preceding the interview. Marital distress was significantly associated with (a) overall mental health service utilization and service utilization provided by each of the sectors of providers when controlling for demographic variables and (b) overall mental health service utilization and receiving treatment from a psychiatrist when additionally controlling for past-year anxiety, mood, or substance use disorders. There was little evidence that the associations between marital distress and service utilization were moderated by gender or presence of psychiatric disorders. Conclusion: The finding that marital distress is associated with greater mental health care service utilization suggests that clinicians should assess both individual and relationship factors among individuals presenting for treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reconfigurable imaging systems using elliptical nanowires

Materials that have subwavelength structure can add degrees of freedom to optical system design that are not possible with bulk materials. We demonstrate two lenses that are composed out of lithographically patterned arrays of elliptical cross-section silicon nanowires, which can dynamically reconfigure their imaging properties in response to the polarization of the illumination. In each element, two different focusing functions are polarization encoded into a single lens. The first nanowire lens has a different focal length for each linear polarization state, thereby realizing the front end of a nonmechanical zoom imaging system. The second nanowire lens has a different optical axis for each linear polarization state, demonstrating stereoscopic image capture from a single physical aperture.     

Multicolored vertical silicon nanowires

We demonstrate that vertical silicon nanowires take on a surprising variety of colors covering the entire visible spectrum, in marked contrast to the gray color of bulk silicon. This effect is readily observable by bright-field microscopy, or even to the naked eye. The reflection spectra of the nanowires each show a dip whose position depends on the nanowire radii. We compare the experimental data to the results of finite difference time domain simulations to elucidate the physical mechanisms behind the phenomena we observe. The nanowires are fabricated as arrays, but the vivid colors arise not from scattering or diffractive effects of the array, but from the guided mode properties of the individual nanowires. Each nanowire can thus define its own color, allowing for complex spatial patterning. We anticipate that the color filter effect we demonstrate could be employed in nanoscale image sensor devices.     

Negative refraction in a Si-polymer photonic Crystal membrane

We have observed negative refraction in a photonic crystal (PC) membrane structure at near-infrared wavelengths. The device is fabricated on a silicon-on-insulator substrate and consists of a silicon rod matrix suspended in a polymer where optical energy is delivered by ridge waveguides with various incident angles. The propagation direction inside the PC shows extraordinary refraction with an angle consistent with our two-dimensional numerical simulations. To our knowledge, this is the first experimental observation of isotropic negative refraction in a Si-based planar PC structure at optical frequencies. The realization of negative refraction in a planar Si-based system enables applications in negative index imaging to be integrated into compact optical circuits.     

Subtypes of partner violence perpetrators among male and female psychiatric patients.

The goal of this naturalistic study was to examine heterogeneity among female and male civil psychiatric patients with a history of intimate partner violence (IPV) perpetration. Participants were 567 patients drawn from the MacArthur Violence Risk Assessment Study (J. Monahan et al., 2001). The authors examined subtype composition among 138 women and 93 men with positive histories of IPV and compared these groups with 111 women and 225 men with no histories of IPV. Findings for men and women were consistent with reports from studies of male perpetrators in forensic and community settings in that generally violent/antisocial, borderline/dysphoric, and family only/low-psychopathology subtypes of perpetrators were identified in both men and women. This study provides preliminary evidence for the generalizability of typologies derived from nonpsychiatric partner violence perpetrators to psychiatric populations and suggests that typologies derived from studies of male IPV perpetrators may provide useful guidance for the investigation of female IPV perpetration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Image inversion and magnification by negative index prisms

A Dove prism and an anamorphic prism pair are investigated in negative index imaging systems. An equilateral triangular prism with refractive index of -1 operates as a negative index Dove prism that inverts as well as images the incident field. A negative index anamorphic prism pair acts as a negative index imaging system with magnification. The relationship between achievable magnification and aberrations is discussed. Both prism systems can be implemented by using negative index photonic crystals, and their performance is demonstrated numerically by the finite-difference time-domain method. These negative index prism structures enhance the functionalities of negative index flat lenses and broaden the applications of negative index materials.