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Thermal regimes of forested headwater streams control the growth and distribution of various aquatic organisms. In a western Oregon, USA, case study we examined: (1) forested headwater stream temperature variability in space and time; (2) relationships between stream temperature patterns and weather, above-stream canopy cover, and geomorphic attributes; and (3) the predictive ability of a regional stream temperature model to account for headwater stream temperature heterogeneity. Stream temperature observations were collected at 48 sites within a 128-ha managed forest in western Oregon during 2012 and 2013. Headwater stream temperatures showed the greatest spatial variability during summer (range up to 10 $$^\circ$$ C) and during cold and dry winter periods (range up to 7.5 $$^\circ$$ C), but showed less spatial variability during spring, fall and wet winter periods (range between 2 and 5 $$^\circ$$ C). Distinct thermal regimes among sites were identified; however, geomorphic attributes typically used in regional stream temperature models were not good predictors of thermal variability at headwater scales. A regional stream temperature model captured the mode of mean August temperatures observed across the study area, but overpredicted temperatures for a quarter of the sites by up to 2.8 $$^\circ$$ C. This study indicates considerable spatial thermal variability may occur at scales not resolved by regional stream temperature models. Recognizing this sub-landscape variability may be important when predicting distributions of aquatic organisms and their habitat under climate and environment change scenarios.

An experimental X-ray powder diffraction pattern was produced and analyzed for alpha-polymorphic tegafur, also called Ftorafur (an antineoplastic agent). The indexed data matched the powder patterns in the ICDD PDF-4/Organics database calculated from the reported single-crystal X-ray diffraction data in the Cambridge Structural Database. Alpha tegafur has a triclinic crystal system, with reduced cell parameters of a=16.720(6) Å, b=9.021(5) Å, c=5.995(3) Å, α=93.66(4)°, β=93.15(8)°, γ=100.14(4)°. There are four formula units contained in one unit cell. The cell volume and space group were determined to be 886.27 Å3 and P-1, respectively.

OBJECTIVE: The objectives of this study were to develop a measure to assess patients' response to civil commitment, to test this measure on two groups of dually diagnosed patients (medically ill alcoholics and patients with dual mental and substance use disorders), and to identify patient characteristics associated with a positive response to commitment. METHODS: The outcome of 38 male veterans civilly committed to inpatient substance abuse treatment for an average of six months was rated by their treating clinicians. Raters used the Commitment Response Form (CRF), a scale anchored to behavioral descriptions that was developed for the study and that measures outcome in five areas: patients' attitude toward recovery, substance use, medical condition, engagement in substance abuse treatment, and independence of functioning. Each patient's medical records were reviewed by two clinical staff members who made independent retrospective ratings and a joint rating using the CRF. They also made independent and joint dichotomous ratings of whether the patient was a positive responder or a nonresponder to civil commitment. RESULTS: The CRF showed superior reliability when compared with the dichotomous rating of outcome. The scale demonstrated reasonable psychometric properties. Mean scale scores did not differ significantly by patient group; slightly more than half were rated as having a good to excellent overall response. Better outcome was associated with longer periods of previous abstinence from alcohol and a higher level of education. CONCLUSIONS: Use of a scale anchored to behavioral descriptions improved reliability of outcome determinations by clinical staff. Civil commitment resulted in good to excellent outcome in many but not all committed patients.

This report documents the findings of a quasi-experimental study of a new approach to treating medically ill alcoholics. The intervention, the Alcohol Related Disorders (ARD) Clinic, consists of concurrent alcohol treatment and medical care delivered by an interdisciplinary team in an outpatient medical clinic at the Minneapolis Veterans Affairs Medical Center (MVAMC).We compared 50 ARD patients with 50 patients who met eligibility for the clinic, but had to be referred elsewhere because the clinic was full at the time (referred patients). Referred patients received medical care in other MVAMC clinics or in the community.During the 2-year follow-up period, ARD patients returned for outpatient visits over three times as often as referred patients (p.001). More referred patients received no follow-up care at MVAMC (p.01). ARD patients had more frequent (p.05) but briefer (p.01) hospitalizations. Almost twice as many referred (32%) as ARD patients (18%) died during the follow-up period. Referred patients ranged from 1.18 times less likely to 5.03 times more likely to die during follow-up than those in the ARD group (p = .11). ARD patients lived for an average of 82 days longer than referred patients, and each ARD clinic visit in the second follow-up year predicted an additional 3.5 days lived (p.01).Integrated outpatient treatment for medically ill alcoholics appears to improve outpatients follow-up and alter patterns of hospitalization when compared with standard approaches. Two-year mortality may have been reduced as a result.

The amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd) has received considerable attention due to its role in amphibian population declines worldwide. Although many amphibian species appear to be affected by Bd, there is little information on species-specific differences in susceptibility to this pathogen. We used a comparative experimental approach to examine Bd susceptibility in 6 amphibian species from the United States. We exposed postmetamorphic animals to Bd for 30 days and monitored mortality, feeding rates, and infection levels. In all species tested, Bd-exposed animals had higher rates of mortality than unexposed (control) animals. However, we found differences in mortality rates among species even though the amount of Bd detected on the different species' bodies did not differ. Of the species tested, southern toads (Anaxyrus terrestris) and wood frogs (Lithobates sylvaticus) had the highest rates of Bd-related mortality. Within species, we detected lower levels of Bd on individuals that survived longer and found that the relationship between body size and infection levels differed among species. Our results indicate that, even under identical conditions, amphibian species differ in susceptibility to Bd. This study represents a step toward identifying and understanding species variation in disease susceptibility, which can be used to optimize conservation strategies.

Measurement of optical absorption loss and photorefractive sensitivity (optically induced index changes) in Ti-diffused waveguides and bulk Ti-doped single crystals are reported. The absorption loss of strip guides is found to be 0.3 dB/cm at 0.633 microm, and this is expected to decrease at longer wavelengths. The results demonstrate that Ti impurities do not contribute to the absorption loss or to the photorefractive-index changes directly, rather these parameters are determined by impurities in the substrate crystal. A simple pyroelectric method for electrical adjustment of the optical input coupling is also reported.

Single-pulse and cw measurements of the response of a semi-insulating CdZnTe/ZnTe multiple-quantum-well photorefractive device are presented. In single-pulse experiments, photodiffractive (absorption) gratings have been written with less than 1.8-microJ/cm(2) incident fluence, and a diffraction efficiency of 1.1% is obtained from the 1.56-microm active layer of the device. With an optimized structure, the ultimate response time of the device can be below 100 ps. In cw measurements a maximum diffraction efficiency of 1.35% is obtained.

We have performed photodiffractive four-wave mixing in semi-insulating multiple GaAs/AlGaAs quantum wells at a wavelength of 0.83 microm. The quantum wells were made semi-insulating by proton implantation, which introduces defects that are available to trap and store charge during holographic recording. The experiments demonstrate how photodiffractive behavior using the large resonant nonlinearities of quantum-confined excitons yields highly sensitive material for optical image processing. When pump powers of 1 mW/cm(2) are used, the measured sensitivity is 2 orders of magnitude greater than that of bulk, nonresonant photorefractive semiconductors.

Order-of-magnitude improvement of the quantum efficiency of metal-oxide-metal detectors is achieved in the visible spectrum by fabricating the devices on silica substrates structured with a periodic array of bumps separated by about 0.25 microm. Structuring metallic films affords improved coupling of the detector to visible light by excitation of localized plasma resonances and surface-plasmon polariton modes. Voltage responsivities of 5 mV/W into a 50-Omega impedance has been demonstrated in preliminary devices. In suitable geometries, such detectors have the potential of subpicosecond response times.

Absorption, luminescence, and excitation luminescence studies of dye molecules adsorbed onto ultrathin, variable-thickness silver films show strong coupling of the particle plasma resonances to the molecules. Luminescence from the dye is increased by excitation transfer from the silver particles for certain film thickness. Increased luminescence has also been observed from dyes on Au and Cu films.

Current oscillations arising from voltage‐controlled negative differential resistivity are observed in optically pumped semi‐insulating InP at low temperature. The presence of high‐field domains sweeping through the sample are detected using photorefractive four‐wave mixing. Direct evidence of the role of defects in these current oscillations is presented using deep‐level photodiffractive spectroscopy. A deep hole trap with an energy Ev +85 meV is observed. The current oscillations occur only when this defect level is partially occupied.

Semi‐insulating multiple quantum well photorefractive devices using GaAs/Al0.29Ga0.71As with an electric field applied perpendicular to the layers are demonstrated. Semi‐insulating behavior is obtained by doping with Cr(1016/cm3) during epitaxial growth of the material. Diffraction efficiencies as high as 3% with an applied voltage of 20 V and microsecond response times are obtained in a 2 μm thick device. These devices are of importance for implementation of fast and sensitive two‐dimensional optical information processing systems at wavelengths compatible with current diode lasers without the spatial‐bandwidth limitations of thick photorefractive materials.

We present results on the operation of a high sensitivity semi‐insulating multiple quantum well device for optical image processing. This device operates in the visible spectrum using II‐VI CdZnTe/ZnTe multiple quantum well structures. Incident light creates charge carriers that screen an applied ac electric field modulating the absorption and refractive index of the structure through the quantum confined Stark effect. In this way, an incident intensity pattern is recorded as an absorption and refractive index variation. The semi‐insulating nature of the material eliminates the need for pixelation. In a wave‐mixing experiment, a peak diffraction efficiency of 0.25% was observed from 2.25 μm active layer of the device. Two‐beam‐coupling gain coefficients of ∼500 cm−1 at wavelengths longer than the exciton absorption peak should be possible.

Optically pumped lasing has been observed up to 100 K in a Cd 0.2 Zn 0.8 Te ZnTe superlattice grown on a GaAs Si substrate. At 100 K, rapid degradation of the lasing signal is seen. This result is inferior to that previously reported for a similar structure grown on a GaAs bulk substrate, for which room-temperature lasing was seen with no degradation. X-ray rocking curve and morphology measurements suggest that the II–VI epilayer has limited ability to heal the extra defects that are present when a GaAs Si , rather than a bulk GaAs, substrate is used.

We report the first study of the room‐temperature electroabsorption effects in CdZnTe/ZnTe multiple quantum well structures which exhibit sharp excitonic absorption peaks. The magnitude of the Franz Keldysh and quantum‐confined Stark Effects are found to be comparable to those of III‐V semiconductors. With optimized structures we expect II‐VI semiconductors to be important components for information processing in the visible spectrum.

Defect levels in semi‐insulating GaAs and InP are investigated by deep level photodiffractive spectroscopy. Temperature‐dependent four‐wave mixing based both on photochromic and photorefractive effects permits a determination of the energy levels within the semiconductor band gap. This optical technique eliminates difficulties encountered with high‐resistivity material using conventional electrical measurements.

We describe the video-rate operation of a compact (30 × 30 × 10 cm) joint transform optical image correlator using two cw diode lasers and a semi-insulating GaAs/AlGaAs multiple-quantum-well photorefractive device as the erasable holographic element. The video images of the objects to be correlated are introduced to the system through a liquid crystal spatial light modulator (SLM) containing 320 × 220 pixels, and the resultant correlation is read out with a CCD camera. With only 1 mW incident write power at 830 nm, the response time of the photorefractive device is sub-microsecond, presenting the possibility of more than 106 correlations per second in a compact system. Furthermore, the small interaction length of the multiple-quantum-well device (2 μm) removes the spatial-bandwidth limitations of correlators based on thick photorefractive materials operating in the Bragg regime. We will discuss the performance of this system for pattern and character recognition.

We have studied the effect of barrier design on the grating period dependence of the diffraction efficiency in semi-insulating GaAs/AlGaAs and CdZnTe/ZnTe multiple quantum well photorefractive devices in the geometry with the applied field perpendicular to the quantum wells. In GaAs/ AlGaAs devices, lowering of the barrier height by reduction of Al concentration from 40% to 30% and reduction of barrier thickness from 100 Å to 35 Å increases the diffraction efficiency by 5 orders of magnitude. This is due to the reduction in carrier sweepout time from the quantum wells reducing the lateral diffusion of carriers in the wells. In an optimized structure, a diffraction efficiency of 3% at 852 nm from a 2 pm thick sample is obtained by application of 20 V. We will discuss the relevant parameters in the design of a photorefractive multiple quantum well device. As an application, the performance of a joint transform correlator based on a multiple quantum well photorefractive device and diode lasers will be discussed.

Experiments have been performed investigating the Rayleigh–Taylor instability initialized with a complex initial perturbation. The experiments utilize a miscible fluid combination with Atwood number A≈0.2. The initially stably stratified fluids are contained within a Plexiglas tank mounted to a linear rail system. The tank was then oscillated vertically to impose nearly sinusoidal three-dimensional internal waves of varying wavelength and complexity at the fluid interface. After imposing this perturbation, the tank is accelerated down the rails at a rate greater than Earth’s gravity (g0) resulting in a body force of approximately 0.8g0. The flow is visualized with either backlit photography or planar laser induced fluorescence. Image sequences from the experiments show bubble and spike merging, leading to a growth of length scale with time. Averaged vertical concentration distributions show self-similarity after ∼233 ms with a total experiment time of ∼300 ms. In addition, after this time, the square root...

FACES III can, however, continue to be a useful scale now that the Circumplex Model has been expanded into a three-dimensional design. Past and future studies would benefit from using FACES III as a linear dimension with high scores representing Balanced types and low scores representing Extreme types. This approach means that many past studies with FACES III need to be re-analyzed and/or re-interpreted in light of this 3-D Model. This revised scoring will significantly increase the number of studies that support the basic hypotheses of the Circumplex model, that Balanced families tend to function in more effective ways. It is clear from more recent work with the Clinical Rating Scale (CRS) that the lack of support for the curvilinear hypotheses of the Circumplex Model is due to the limitations of the FACES instrument and not the underlying theoretical model. The CRS clearly demonstrated the curvilinear pattern that has been hypothesized. It is important that future studies using FACES III analyze data in a linear way that fits with the three-dimensional model. In this way, there is a better match conceptually and methodologically between FACES III and the Circumplex Model. It is also highly recommended that future studies use both the self-report of FACES and the observational approaches to family assessment of the Clinical Rating Scale. This combined approach will help advance the field conceptually, methodologically, and clinically.

We use semi-insulating multiple quantum wells to combine the holographic properties of the photorefractive effect with the large resonant optical nonlinearities of quantum-confined excitons. GaAs–AlGaAs multiple-quantum-well structures are made semi-insulating by proton implantation. The implant damage produces defects that are available to trap and store charge during transient holographic recording by means of coherent excitation. The advantages of charge storage and resonant optical nonlinearity combine to produce new optical devices with large sensitivities. The potential use of these devices for image processing is demonstrated by using the Franz–Keldysh effect in four-wave mixing at wavelengths near 830 nm.

Experimental and simulated powder X-ray diffraction patterns obtained for ZSM-5 zeolites with silica-alumina ratios of 70:1 to Vertical Bar3: 3,000:1 show that the pattern of as-synthesized samples are consistent with idealized orthorhombic symmetry, but that the patterns of samples converted to the ammonium or hydrogen forms exhibit a change to monoclinic symmetry. The change is a reversible, displacive transformation between two symmetry forms that causes no change in framework topology. Generally, the higher the silica-alumina ratio, the easier is the change from the parent orthorhombic to monoclinic symmetry after treatment.

The potential of certain color centers to make efficient broadly tunable cw lasers for the infrared is discussed. We show how the range 0.9 ≲λ≲3.3 μm can be covered by using FA(II), FB(II) and F+2 centers. The pertinent physics of these centers is reviewed and appropriate laser cavity configurations are discussed. The construction and performance of an advanced FA(II) laser is reported. Finally, the possible use of color centers in distributed feedback devices is discussed.

Enhanced second-harmonic generation is observed from silver and gold island films, and from regular arrays of Ag particles produced by microlithographic techniques. Enhancements are interpreted in terms of an electromagnetic model involving localized surface-plasma oscillations. The regular arrays allow the separation of fundamental and second-harmonic beams by a novel grating effect.

Amorphous silicon films have previously been utilized to make high speed photoconductive detectors with response times ranging from 4–200 psec in microstrip transmission line structures. However, in typical devices, the low carrier mobilities resulted in poor carrier collection efficiencies resulting in quantum efficiencies in the range 0.001–0.3%. We have demonstrated photogenerated carrier sweep-out in Schottky barrier photodetectors with internal quantum efficiencies of 36% (0.18 A/W) and sampling oscilloscope limited response times of 40 psec (FWHM) using 100 nm-thick films of rf-glow discharge deposited a-Si:H in a new transmission line structure. The estimated deconvolved response time was 27 psec. These a-Si:H detectors are compared in speed and sensitivity to high mobility crystalline detectors.

The nonequilibrium occupation of multiple defect states in inhomogeneously illuminated crystals is demonstrated to have dramatic and previously unexpected consequences for the photorefractive behavior of electro-optic semiconductors. By using a simple screening formalism, we show for the first time that the standard photorefractive effect can be partially or entirely quenched. This nonequilibrium screening is observed in the thermally stimulated relaxation of diffraction efficiencies in four-wave mixing experiments performed on semi-insulating InP

The potential of ferroelectric liquid crystals for application as pyroelectric infrared detectors is examined. The liquid crystals studied belong to a family of biphenyl and phenylbenzoate esters. It is found that even within this first liquid‐crystal family examined, the materials figure of merit compares well with ferroelectric solid materials commonly used for infrared detection and imaging. Because they permit very simple and flexible device design, liquid crystals are attractive candidates for these applications. However, for low‐frequency applications, attention must be paid to the reduction of thermal loading by the cell walls.

Electron tunneling techniques have been used to examine the characteristics of current ($I$) vs voltage ($V$) in degenerate $n$-type KTa${\mathrm{O}}_{3}$ Schottky barriers at 1 \ifmmode^\circ\else\textdegree\fi{}K. The $\frac{{d}^{2}V}{d{I}^{2}}$-vs-$V$ curve exhibits structure at each of the four LO modes in KTa${\mathrm{O}}_{3}$: 22.5, 34, 51.5, and 102.5 mV. Several two-phonon peaks were also seen and identified as 51.5 + 102.5 = 154-mV and 2 \ifmmode\times\else\texttimes\fi{} 102.5 = 205-mV combinations. The almost antisymmetric nature of the phonon-induced structure about zero bias indicates that it is caused by the inelastic interaction of the tunneling electrons with phonons in the barrier. In addition, the maximum in the differential resistance $\frac{\mathrm{dV}}{\mathrm{dI}}$ occurs at a bias equal to the Fermi level of the semiconductor, and an effective conduction-band mass ${m}^{*}=0.5{m}_{0}$ of the free carriers has been determined.

The crystal chemistry of rare earth faujasites, synthetic and natural, has been investigated by structural studies based on single crystal and powder X-ray data. All rare earth ions in freshly exchanged natural faujastie are contained within the 13 A diameter large cavity, with partial occupancy of the site located in the center of the 12 tetrahedra ring. In zeolite Linde X, however, the rare earth ions partially dehydrate and occupy six tetrahedra ring sites in the large cavity. Upon dehydration, all rare earth ions (RE) move into the sodalite cage cavity, where each metal ion is coordinated to three framework oxygens RE-O = 2.52 ± 0.01 A, and up to three water oxygens RE-O = 2.44 ± 0.08 A, in approximately octahedral coordination. All rare earth ions in both zeolites Linde X and Y can be accommodated by this sodalite cage complex.

cw laser action in an optically pumped Li‐doped KCl crystal containing FA (II) centers has been demonstrated. The laser wavelength was continuously tunable over the range 2.6–2.8 μm. Pump power at threshold was 50 mW, and threshold powers in the submilliwatt range can be predicted for an improved cavity design. Laser action was obtained for crystal temperatures in the range 77≲ T ≲ 200 °K.

The first study of the photorefractive properties of doped CdTe has demonstrated high sensitivity for optical processing applications. Of the binary II‐VI and III‐V semiconductors, CdTe has the highest electro‐optic coefficient r41 in the infrared, some three times larger than that of GaAs and InP. Deep levels introduced into CdTe exhibit appropriate absorption and photoconductivity at 1.06 μm by doping with V and Ti impurities. Photorefractive beam coupling experiments in CdTe:V gave small signal gains of 0.7 cm−1, and diffraction efficiencies with no applied electrical field of 0.7%. Thus, CdTe appears to be superior to previously studied III‐V semiconductors, in the near‐infrared spectrum. Optimization of doping and trap densities is expected to result in gain which exceeds the absorption loss, thereby allowing phase conjugation with infrared injection lasers.

A spectrometer for making absolute absorption measurements is described. The system is especially suitable for work with solid state samples at low temperatures. Both sample and reference beams pass through the same set of Dewar windows, making compensation for the losses in these unnecessary. Simplicity and low cost are achieved by using a chopper wheel of special configuration rather than the usual rotating mirror. Direct measurement of optical densities as high as 4.0 is possible.

Making use of the photorefractive effect, we have developed a versatile method of imaging various crystal properties of semi‐insulating compound semiconductors. The magnitude and time evolution of refractive index gratings are monitored via diffraction. The observed diffraction is directly related to the electric fields present, and quantitative information concerning the spatial variation of dark conductivity, photoconductivity, and deep level absorption can be extracted. Wafers of undoped GaAs and InP:Fe have been characterized in this manner, and comparisons of images are made which demonstrate the capabilities of this technique.

Optically pumped lasers emitting near 600 nm at room temperature have been fabricated for the first time in Cd0.25Zn0.75Te/ZnTe superlattices grown on GaAs substrates. The threshold pump intensity using pulsed 0.53 μm radiation increased from ∼7 kW/cm at 10 K to ∼60 kW/cm2 at room temperature with a threshold temperature dependence described by T0∼111 K.

We report here for the first time the demonstration of self‐pumped phase conjugation in photorefractive semiconductors using 1.32 μm light. Using an ac field technique to enhance the gain coefficient in InP:Fe and a single input pump beam, phase conjugate reflectivities of 11% were measured using an input beam intensity of less than 1 mW/mm2. These results open up many possibilities for using photorefractive semiconductors in applications with low‐power infrared diode lasers.

An asymmetric δ‐doped GaAs structure is described which exhibits novel photovoltaic effects and low‐intensity nonlinear optics. Of particular interest in this kind of structure is the ability to design the electro‐optical and nonlinear optical properties and the material response time over a wide range by appropriate design of the doping profile.

Stable room‐temperature light emission has been observed from planar Mg‐MgO‐Ag junctions. The light emission is presumably due to roughness‐induced radative decay of surface plasma modes excited by tunneling electrons. Roughening of the planar tunnel structure is obtained by growth of a plateletlike structure during slow evaporation of the Mg film.

The photorefractive effect has been observed for the first time in semi‐insulating InPe:Fe and GaAsCr. These materials are sensitive and versatile recording media for high bit rate parallel optical processing in the 0.8–1.8‐μm spectral region using injection lasers of milliwatt power levels.

A hard and durable antireflection coating that bonds well to cadmium sulfide has been developed. Silicon monoxide films evaporated at 140°C substrate temperature produce homogeneous films with high adhesion and solvent resistance. These films raise the Air Mass 2 short circuit currents of single‐crystal InP/CdS solar cells by 18.5% and of polycrystalline InP/CdS cells by 15.5%.

La modulation spatiale par le gelage optique des defauts EL2 du GaAs. Le gradient spatial du niveau de Fermi est a l'origine de champs electriques internes bien superieurs a ceux generes par la seule diffusion thermique. La structure de bande resultante est equivalente a une structure p-i-p periodique a dopage module faisant alterner les couches isolantes et a la conductivite de type p. Les champs internes sont detectes par un effet electrooptique different de l'effet photorefractif normal

Amorphous silicon Schottky barrier photodetectors with internal quantum efficiencies of 36% and sampling oscilloscope limited response times of 40 ps (full width at half‐maximum) have been fabricated. Utilizing ultrathin films of rf glow discharge deposited hydrogenated amorphous silicon, carrier sweep‐out was achieved in a new microstrip transmission line structure. The performance of these devices, for picosecond pulse detection, is now comparable to that of crystalline semiconductor detectors.

Enhanced optical absorption has been obtained in thin (∼30 nm) layers of hydrogenated amorphous silicon by depositing films on periodically structured substrates. At the appropriate angle of incidence, light is coupled to a surface wave in the abosrbing ‘‘artificial dielectric’’ region formed by the structured interface. This effect is used as the basis of high‐speed metal a‐Si:H metal detectors to overcome the conflicting requirements of high optical absorption and short transit times in thin layers. Peak response as high as 0.16 V is achieved for 50‐pJ incident pulses of picosecond duration. This is comparable to that obtained with much higher mobility crystalline semi‐insulators.