Double layer SiO2-TiO2 sol-gel thin films on glass for antireflection, antifogging, and UV recoverable self-cleaning.

Double layer thin films, mechanically stable and adhering to glass, were produced through the sol-gel process, using tetraethyl orthosilicate and titanium butoxide as precursors. The refractive index of the titania and silica-titania composite layers were typically 2.1 and 1.7, and their physical thicknesses were approximately 65 nm and 81 nm, respectively, as determined by ellipsometry. These optical constants allowed attainment of quarter-wave optical thicknesses at the center of the visible spectrum (550 nm) as designed, with an increase of 3.4% in transmittance. The nanometric surface roughness, measured by optical profilometry, was effective to decrease light scattering and water contact angles to below 10°. As novelty in dip-coated sol-gel films, superhydrophilicity for self-cleaning, antifogging, and antireflection in the mid-visible spectrum were simultaneously attained with durability of 9 weeks in the dark. Further application of UV light allowed regeneration of contact angles for self-cleaning.

Spectrally extended, near-surface refractive index determination: atomic layer deposited TiO2 on Si.

The optical performance of very thin films has always been difficult to measure, and it has been a gray area due to interface and coating imperfections. Atomic layer deposition has produced pinhole-free, continuous, and extremely pure Titania films, with precise control at monolayer level, on native oxide/Si substrates, whose atomic force microscopy imaged nano-topology is approximately followed. For interface probing, the Abelès method is extended to the visible spectrum, and Cauchy dispersion curves are fitted to the refractive index experimental data, showing excellent compatibility with ellipsometric analysis. This is possible with decreasing optical thickness until ∼1/10 quarterwave is reached, which sets a limit for the usual optical film behavior.

Spin-coating process evolution and reproducibility for power-law fluids.

A distinct development of an exact analytical solution for power-law fluids during the spin-coating process is presented for temporal and spatial thickness evolution, after steady state conditions are attained. This solution leads to the definition of a characteristic time, related to the memory of the initial thickness profile. Previously obtained experimental data, for several rotation speeds and carboxymetilcellulose concentrations in water, are quantitatively analyzed through the evaluation of their characteristic times and compared with theoretical predictions, thus allowing better understanding of thickness profile evolution and of process reproducibility.

Optical monitoring for power law fluids during spin coating.

Optical monitoring is applied, in situ and in real time, to non-newtonian, power law fluids in the spin coating process. An analytical exact solution is presented for thickness evolution that well fits to most measurement data. As result, typical rheological parameters are obtained for several CMC (carboximetilcelullose) concentrations and rotation speeds. Optical monitoring thus precisely indicates applicability of the model to power law fluids under spin coating.

Child development and the PITS: simple questions, complex answers, and developmental theory. Person in the Street.

The enormous popular interest in the field of child development makes it incumbent upon developmental scientists to convey with care the complexity of development lest oversimplified popular accounts gain credibility. Recent attempted models of development do include the range of variables and complexities that need to be accommodated in accounting for development. A model is presented here that incorporates many of the elements of recent models but elaborates on the role of experience in relation to the constitutional, cultural, economic, and social factors that contribute to advantages and disadvantages in children's development. The importance of accommodating data from prior theoretical perspectives and the importance of the contributions from neuroimaging studies are discussed as they are critical for successful theory building in the field of child development.

Generalized abelès relations for an anisotropic thin film with an arbitrary dielectric tensor: comments.

The Cojocaru generalization of the 2 x 2 extended Jones matrix method, placed in a wider context of previous approaches to anisotropic optical thin films, is analyzed from a complementary perspective. This, contrary to initial belief, allows for a simple proof that one may include multiple reflections by taking into account total fields into the anisotropic film, and this therefore provides support for a more widespread use of the method.

Envelope and waveguide methods: a comparative study of PbF(2) and CeO(2) birefringent films.

We have characterized low-birefringence, PbF(2) coatings to permit, first, agreement between envelope and prism-coupler waveguide methods under the standard isotropic assumption. In essentially the same measurement conditions, for obliquely deposited (58.3°) CeO(2) coatings the isotropic model becomes unsustainable. Explicit consideration of the film microstructure is then required for good correlation between thickness results from TE (503 ± 9 nm) and TM (504 ± 10 nm) modes in the waveguide experiment as well as between refractive-index results from envelope (n(2) = 1.78 ± 0.03) and waveguide (n(2) = 1.794 ± 0.002) techniques. We considered uniaxial and biaxial models to achieve consistency, and the refractive indices along the principal axes of symmetry were determined.

Targeting infant stimulation efforts. Theoretical challenges for research and intervention.

Summarized in this article is the historical background concerning infant stimulation. By putting the concerns in a broader developmental context, an intensive review of the principal issues and concepts in current developmental theory and an analysis that is at once selective and eclectic in its overall approach is achieved.

The multiple partnership. Scientist, university, agency, and government.

In the United States a large and significant percentage of scientific effort is carried out in universities and financed by government and private agencies. The partnership between universities and research support agencies relies on individuals representing their scientific organizations, their universities, and their agencies. These individuals deal with the ideas, the proposals, and advocacies that push and shape the programs that ultimately become established. The organizational and political realities that drive and influence this partnership are described in a way that highlights the ensuing richness, diversity, and the sometimes wasted efforts that characterize American science. Present-day science advocacy in the United States is placed in perspective as it is compared with an ideal, advocacy-free system and to other systems that have existed historically.

Neonatal state profiles: reliability and short-term prediction of neurobehavioral status.

Observations were made on 40 newborns prior to hospital discharge in which states were scored every 10 sec in two 35-70-min periods separated by 6-48 hours. Newborns' states, particularly sleep states and crying, were fairly reliable across observation sessions. Cluster analyses identified 3 separable state profiles that subsequently differentiated infants on the Neonatal Behavioral Assessment Scale with Kansas Supplements (NBAS-K) at 2 weeks of age. Additionally, state observations and NBAS-K exams showed significant agreement on individual differences in neurologically based measures, such as startles, tremulousness, and lability of state.

Using developmental theory to guide the search for the effects of biological risk factors on the development of children.

A structural-behavioral model of development is described as providing a basis for formulating hypotheses about the effects of biological risk factors on the development of children. It takes into account the contributions to development that come from organismic and environmental variables. These influences are modified by the effect of individual resiliency in the face of social and biological risk factors. Organismic, environmental, and individual differences are seen as making different contributions in different domains and at different periods of development. A distinction is made between the development of universal and nonuniversal behaviors. From this model, hypotheses can be derived about the effects of social and biological risk factors. The implications for developmental research designs are discussed as are the kinds of behavioral measures most likely to be sensitive enough to detect the effects of social and biological risk factors on the development of children.

Infant visual attention in the paired-comparison paradigm: test-retest and attention-performance relations.

The visual behavior of infants in the paired-comparison paradigm was assessed with multiple discrimination tasks week-to-week at 4 and 7 months and longitudinally from 4 to 7 months. Results indicated that although task-to-task reliability was extremely variable and typically low, most measures of infants' attention averaged across multiple tasks were reliable from 1 week to the next as well as relatively stable over the longer longitudinal period. Across all groups, infants who had shorter fixations (i.e., more fixations per fixed-exposure period) during the familiarization phase showed higher novelty preferences. While infants' shift rate during test phases was a reliable individual characteristic at 7 months, it was not at 4 months; rather, data suggested that the difficulty of the stimulus discrimination may be related to young infants' shift rate.

Neonatal behavioral organization and visual processing at three months.

In 2 studies, the Range of State cluster derived from infants' scores on the Neonatal Behavioral Assessment Scale with Kansas Supplements (NBAS-K) was found to correlate significantly with visual discrimination performance at 3 months of age. Contrary to the expectation that NBAS-K orientation scores would predict visual discrimination at 3 months, it was neonatal behavioral state organization that related to later cognitive functioning in infancy.

The stability of visual habituation during the first year of life.

The short-term reliability and long-term stability of visual habituation and dishabituation in infancy were assessed in a sample of 186 infants from 4 age groups (3-, 4-, 7-, and 9-month-olds) seen for 2 within-age sessions and in a sample of 69 infants seen longitudinally at 3, 4, 7, and 9 months of age. Moderate week-to-week reliability (r's = .30-.50) was observed for duration-based and magnitude of habituation variables at all ages, although better reliability was evident at 4 and 9 months than at 3 and 7 months. In most cases, the reliability of habituation magnitude measures was attributable to the reliability of the peak fixation alone. Data from the longitudinal sample suggested that only the duration of peak fixation was consistently stable across the ages tested, although stability for several measures emerged across the 7-9-month testing. No consistent reliability or stability emerged for the presence or magnitude of dishabituation in either sample.

Infants' attentional responses to frequency modulated sweeps.

In 3 experiments, the attentional responses of 4-month-old infants to frequency-modulated (FM) sweeps corresponding to the frequency range of adult-to-infant and adult-to-adult intonation patterns were assessed. In Experiment 1, infants were observed to discriminate "exaggerated" (i.e., adult-to-infant) FM sweeps from "normal" (i.e., adult-to-adult) FM sweeps in a habituation-dishabituation paradigm but did not selectively attend to one over the other. In Experiment 2, where the same stimuli were used in a paired-comparison paradigm, again no differential attention was observed. In Experiment 3, the most exaggerated sweep was paired against a continuous, monotonic pure tone, but again no difference in salience was observed. These data suggest that the extent of modulation or intonation of an auditory stimulus per se does not constitute a salient cue for infants' attention to sound.

Stimulation in the NICU: is more necessarily better?

Animal studies and studies with human full-term infants suggest that the stimulation present in utero affects postnatal preferences and levels of response. The premature infant does not necessarily benefit from a re-creation of the in utero environment. Each aspect of the in utero environment should be assessed independently as a potential source of added stimulation in the NICU to determine its possible effects on the development of the premature infant. The NICU environment cannot be accurately labeled by global descriptors of "deprivation" or "overstimulation." When compared with the home environments of full-term infants from lower SES homes, different aspects of the NICU environment were recorded more often, less often, or equally as often as in the full-term infants' homes. Baseline levels of stimulation should be recorded in any NICU environment prior to the institution of an intervention program. NICU caregivers tended to respond contingently to their premature patients' behaviors. However, the prematures provided few opportunities for the nurses to respond, when visual and vocal behaviors used by full-term infants were employed as the expected norm. Perhaps both the medical staff and parents should be trained to recognize and respond to the more subtle, different cues described by Als et al. as being prevalent in the behavioral repertoire of the premature infant. Based on ecologic descriptions of NICU's, researchers have suggested that an inappropriate pattern of stimulation may characterize the environment, rather than an inappropriate amount of stimulation. The NICU environment has been characterized as providing little cross-modal stimulation, few temporally patterned stimuli, and little diurnal rhythmicity. In addition, the premature infant may have few opportunities to control the environment, contrary to the full-term infant's experiences. There is evidence of some negative effects of added NICU stimulation. Individual infants should be assessed prior to intervention for their level of behavioral maturation. Interventions should be individualized for the particular needs of each infant, rather than subjecting all infants assigned to a treatment condition with a stimulation "package." The worthy goal of promoting the development of premature infants carries with it the responsibility of ensuring that no harmful effects could befall any one infant.