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Over half (56 percent) of America’s forests are privately owned and managed and provide a vast array of public goods and services, such as clean water, timber, wildlife habitat, and recreational opportunities. These important public benefits are being affected by increased housing density in urban as well as rural areas across the country. The Forests on the Edge project, sponsored by the U.S. Department of Agriculture, Forest Service, seeks to improve our understanding of where across the country housing density increases, as well as other threats, might affect these critical goods and services. For this study, we map and rank watersheds across the conterminous United States to analyze the relative contributions of private forest land to water quality, timber volume, at-risk species habitat, and interior forest. In addition, we rank watersheds according to the pressures on private forest contributions from increased housing density, wildfire, insect pests and diseases, and air pollution. Results indicate that private forest land contributions to forest cover, clean water, and timber volume are greatest in the East, but are also important in many Western watersheds. Private forests making substantial contributions to interior forest and at-risk species are more uniformly distributed across the country. Development pressures on these contributions are concentrated in the Eastern United States but are also found in the north-central region, parts of the West and Southwest, and the Pacific Northwest; nationwide, more than 57 million acres of rural forest land are projected to experience a substantial increase in housing density from 2000 to 2030. Private forests in both the Eastern and Western United States are under pressure from insect pests and diseases. The bulk of private forests most susceptible to wildfire are located in the West and parts of the Southeast. Lastly, ozone pollution affecting private forests is localized in California and several areas of the East.

RESUMENUno de los temas más controvertidos dentro de la literatura sobre gestión de la innovación es el grado en que estos procesos son controlables y planificables. Esta literatura ha evolucionado desde una posición racional dentro de la cual los procesos de innovación son el resultado de decisiones racionales, intencionadas y debidamente planificadas, a una posición más evolutiva en la cual si bien no es posible controlar y gestionar el proceso directamente, si que lo es controlar el las condiciones del contexto organizativo de la innovación con objeto de incrementar el éxito del proceso. En este artículo, analizamos el proceso de innovación desde un nuevo paradigma que va más allá de los anteriores y que se fundamenta en los postulados de las teorías de la complejidad y en la asimilación de los procesos de innovación a los procesos de cambio institucional. Desde esta nueva perspectiva, se deduce que los procesos de innovación y el cambio institucional consiguiente tienen una base pragmática y, en consecuencia, el potencial para la planificación y control de los procesos de innovación se ve altamente limitado.ABSTRACTOne of the most controverted subjects in the literature on innovation management is the extent to which these processes can be controlled and planned. This literature has evolved from a rational position in which the innovation processes are the result of rational decisions, deliberate and properly planned, to a more evolutionary approach. From this evolutionary perspective the control and management of the process is made indirectly by controlling and intervening on the organizational context of the process of innovation process. In this article, we analyze the innovation process from the perspective of a new paradigm that goes beyond the previous two. It lies on the postulates of the complexity theories and takes the processes of innovation as processes of institutional change. From this new perspective, we deduce that the processes of innovation and the consequent institutional change have a pragmatic basis, and consequently, the potential for the planning and control of the innovation processes is seen highly limited.

The use of molecular beam epitaxy to produce heterostructures has made it possible to better study superlattices with monolayer and submonolayer period spacings. In this work we examine the physical properties for the superlattice system (GaAs) n 1 (AlAs) n 2 /GaAs(001) for low values of n 1 and n 2 , i.e. n 1 = n 2 = 3,6,12. Normal, interrupted growth, and migration-enhanced epitaxy growth techniques were used to grow the superlattice structures and the X-ray diffraction spectra were obtained and the major and satellite peak positions analyzed. An analysis of the major diffraction peaks and their associated satellites exhibited superlattice periodicity in good agreement with theory. Diffraction peaks were also observed in regions adjacent to the primary diffraction peaks which did not occur in the expected satellite positions. An analysis of these peaks relative to the primary peaks indicates periodicities which are greater than the intended period. One possible cause for these periodicities is variations in growth conditions which occur while the superlattice is being grown. An understanding of low-order superlattices is important for structures which are dependent on interface sharpness.

The lattice damage and the nature of the atomic intermixing of Al and Ga induced by As++ implantation and thermal annealing in AlAs/GaAs multiple quantum‐well structures were investigated. The photoluminescence spectra, which show multiple peaks after implantation and annealing, were analyzed based on the shifts of the excitonic peaks arising from quantum wells located at different depths. The depth profiles of intermixing were obtained using a procedure of successive layer‐by‐layer chemical etching followed by photoluminescence measurements. It is found that the atomic mixing is maximum near the sample surface and decreases monotonically with depth, suggesting that the profiles follow more closely the ion induced damage than the ion density. It is also observed that the radiation damage extends beyond 1 μm. Within 0.3 μm from the surface, the damage is relatively heavy and the atomic intermixing increases rapidly with ion dose. Beyond 0.3 μm, the degree of intermixing is only sensitive to the anneal temperature but not to the implantation dose. The results show that both direct collisions and interdiffusion are responsible for the atomic mixing. For the samples implanted with ion doses below 1014 cm−2 and annealed at 650 °C, the optical activation from radiation damage is appreciable. However, the interdiffusion becomes important only at temperatures near and above 800 °C.

Cyclone pressure drop decreases when dust concentration in the gas increases, when an inlet vane is installed. In this work, experimental data have been obtained for two different configurations (with and without inlet vane) in order to study these effects; these data have been compared with results published by other authors. Empirical correlations have been obtained to predict pressure drop as a function of dust load for these operating conditions. Finally, the influence of an inlet vane on cyclone collection efficiency has been studied; for large particles, the efficiency is not affected, but with smaller particle diameters, the inlet vane causes a slight reduction in collection efficiency.

Este artículo presenta una visión del concepto de calidad de la educación superior que ha prevalecido en México a partir de las políticas públicas modernizadoras que ha implementado el gobierno federal. Se centra en el análisis de la transformación de la institución universitaria a la organización universitaria y enfatiza dos de los principales instrumentos que han acelerado dicho proceso: los estímulos para los docentes y el Programa de Fortalecimiento Institucional (PIFI) para las instituciones. Concluye que la organización universitaria es un objeto que se adapta y asume la transformación primordialmente porque detrás de ella se encuentra el financiamiento para desarrollar las funciones sustantivas de la Universidad.

Many of America’s national forests and grasslands—collectively called the National Forest System—face increased risks and alterations from escalating housing development on private rural lands along their boundaries. National forests and grasslands provide critical social, ecological, and economic benefits to the American public. This study projects future housing density increases on private rural lands at three distances—2, 3, and 10 miles—from the external boundaries of all national forests and grasslands across the conterminous United States. Some 21.7 million acres of rural private lands (about 8 percent of all private lands) located within 10 miles of the National Forest System boundaries are projected to undergo increases in housing density by 2030. Nine national forests are projected to experience increased housing density on at least 25 percent of adjacent private lands at one or more of the distances considered. Thirteen national forests and grasslands are each projected to have more than a half-million acres of adjacent private rural lands experience increased housing density. Such development and accompanying landscape fragmentation pose substantial challenges for the management and conservation of the ecosystem services and amenity resources of National Forest System lands, including access by the public. Research such as this can help planners, managers, and communities consider the impacts of local land use decisions.

The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments.

Quality control is difficult to achieve in Congenital Heart Surgery (CHS) because of the diversity of the procedures. It is particularly needed, considering the potential adverse outcomes associated with complex cases. The aim of this project was to develop a new method based on the complexity of the procedures.The Aristotle project, involving a panel of expert surgeons, started in 1999 and included 50 pediatric surgeons from 23 countries, representing the EACTS, STS, ECHSA and CHSS. The complexity was based on the procedures as defined by the STS/EACTS International Nomenclature and was undertaken in two steps: the first step was establishing the Basic Score, which adjusts only the complexity of the procedures. It is based on three factors: the potential for mortality, the potential for morbidity and the anticipated technical difficulty. A questionnaire was completed by the 50 centers. The second step was the development of the Comprehensive Aristotle Score, which further adjusts the complexity according to the specific patient characteristics. It includes two categories of complexity factors, the procedure dependent and independent factors. After considering the relationship between complexity and performance, the Aristotle Committee is proposing that: Performance = Complexity x Outcome.The Aristotle score, allows precise scoring of the complexity for 145 CHS procedures. One interesting notion coming out of this study is that complexity is a constant value for a given patient regardless of the center where he is operated. The Aristotle complexity score was further applied to 26 centers reporting to the EACTS congenital database. A new display of centers is presented based on the comparison of hospital survival to complexity and to our proposed definition of performance.A complexity-adjusted method named the Aristotle Score, based on the complexity of the surgical procedures has been developed by an international group of experts. The Aristotle score, electronically available, was introduced in the EACTS and STS databases. A validation process evaluating its predictive value is being developed.

The fusogenic (F) membrane glycoprotein of the paramyxovirus SV5 allows virus to enter host cells and mediates fusion between neighboring cells, which leads to cell death. F glycoprotein is synthesized as an inactive precursor (F(0)) that is cleaved by cellular protease furine to form the active heterodimer F(1) + F(2). The active protein can induce syncytium formation in the absence of another integral glycoprotein (HN), a property that appears to be unique among paramyxoviruses.We constructed a non-replicative adenovirus to express SV5 F protein in tumor cells, and its fusion capacity was analyzed by fluorescent and confocal microscopy. Cell viability and bystander effect were compared with the thymidine kinase/ganciclovir suicide gene therapy. The structure of F-expressing cells was studied using electron microscopy.F glycoprotein expression induced syncytium formation to a maximum at 72 h, after which syncytia progressively lost viability and detached. The cell membrane was disrupted while nuclear structure was preserved. Over-expression of SV5 F protein in tumor cells led to high cytotoxicity comparable with that associated with the thymidine kinase/ganciclovir. A potent bystander killing effect was detected until the ratio of F-transduced to non-transduced cells was 1 : 100.These results indicate that the fusogenic glycoprotein of the paramyxovirus SV5 could be used to eliminate tumor cells and may encourage studies aimed at modifying its selectivity and combining its expression with other cytotoxic strategies to improve their efficacy.

The accumulation of cytoplasmic polyhydroxyalkanoates (PHAs) and the heterogeneity ofbacterial populations were analysed by flow cytometry and SYTO-13 and Nile red staining in rhamnolipid-producing Pseudomonas aeruginosa cultures grown in waste frying oil as carbon source. A combination of SYTO-13 and Nile red fluorescence with cytometric forward and side scatter values may allow increases in the final production of polyhydroxyalkanoates (PHA) by two basic mechanisms: (i) rapid assessment of polyhydroxyalkanoate content and (ii) definition of flow cytometric cell sorting protocols to select high polyhydroxyalkanoate (PHA)-producing strains. We report a rapid (less than 30 min) flow cytometric assessment of PHAs in Pseudomonas aeruginosa 47T2 following Nile red staining: (i) to estimate cellular PHAs content; (ii) to study heterogeneity of the batch cultures producing PHAs and (iii) to establish the basis for sorting sub-populations with a high capacity to accumulate PHAs.

Congenital tracheal stenosis (CTS) is a rare malformation that usually require corrective surgery. Resection and tracheal anastomosis is the treatment of choice when the stenosis is short. However, such an approach is not usually viable when the CTS is long, given that anastomotic pressure would be too great. New surgical techniques have allowed this serious airway malformation to be corrected satisfactorily. We report the case of a three-year-old boy with a long CTS (51% of the length of the trachea) treated with a new reconstructive technique called slide tracheoplasty. Outcome was excellent.

The specific nucleic acid fluorochrome SYTO-13 was used in flow cytometric analysis to assess changes in the density and heterogeneity of marine bacterial populations which biodegrade linear alkylbenzene sulphonate (LAS). Seawater samples with LAS and incubated in the laboratory (20 degrees C, 100 rpm, 30 days) were used to monitor LAS-degrading consortia. Flow cytometric studies and culture methods were used to characterize the LAS degrading bacterioplankton consortia. Fluorescence and scatter signals enabled us to define three regions (R1, R2 and R3) in the dual parameter cytograms. The distribution of the bacterial counts in these regions allowed us to monitor the formation and evolution of the consortia.

We have quantified unintentional indium incorporation in GaAs grown by molecular beam epitaxy in a variety of commercial systems. We find that the unintentional indium density in the epitaxial GaAs is more a function of mounting technique and prior machine history than of the manufacturer’s design. The indium densities detected in the epitaxial GaAs for substrates that only partially obscure an indium‐bearing mount are equal to levels reported to result in minimum defect densities and narrowest photoluminescence linewidths in In‐doped GaAs.

Assessment of cell viability using methods which do not require cell culture is essential in the field of aquatic microbiology, since many bacteria known to be present in aquatic environments cannot be grown in culture. The study of bacterial biofilms, which previously needed an epifluorescent microscope, has recently been enhanced by the use of flow cytometry and confocal scanning laser microscopy (CSLM). A method based on the combination of several membrane potential related dyes, a membrane integrity dye and a redox probe was used to measure cell viability by flow cytometry and confocal laser microscopy. Rhodamine-propidium iodide (PI) double staining was used to discriminate viable from nonviable cells in CSLM observations. Membrane depolarization during E. coli and Salmonella starvation measured by DiBAC4(3) incorporation (flow cytometry and CSLM) was found to be in concordance with respiratory activity as detected by a tetrazolium salt (CTC) reduction.

Two membrane potential sensitive dyes (Rhodamine 123 and bis-oxonol) and three nucleic acid dyes (propidium iodide, SYTO-13, and SYTO-17) were used to assess the effect of surfactants on Escherichia coli. The ability of E. coli to be stained by these probes was validated at different physiological states. Propidium iodide was used to assess the integrity of cell envelopes. Two double staining methods based on propidium iodide with SYTO-13 and bis-oxonol with SYTO-17 were used to improve the discrimination between bacteria and micelles or aggregated particles generated by the presence of surfactants. A rapid (1 h contact time between cells and surfactants, and less than 5 min for staining and obtaining data) Rhodamine 123 flow cytometric assay was developed to assess the bactericidal effect of surfactants.

Flow cytometry was used to study the lag, exponential, stationary and death phases of non-fixed cultures of Escherichia coli. Fluctuations in the forward angle scatter signal (FALS) were compared with cell size as measured by scanning electron microscopy at low temperature and image analysis. A correlation between FALS and cell size was not observed, although a correlation (r = −0.8) was obtained between FALS and the age of the culture for the first eleven days of incubation. Marked increases in FALS were observed during the lag phase, which were attributed both to changes in size and changes in structure or chemical composition. The distribution of FALS for all culture phases was asymmetric, and was associated with the cell size distribution.

The formation of mismatch dislocations in layered semiconductor structures was found recently in high resolution monochromatic synchrotron x-radiation diffraction images to be correlated with characteristics of the substrate as well as with the layer thickness and degree of lattice mismatch of non pseudomorphic layers.1,2We have now extended these studies to examine the accommodation to strain as a function of lattice mismatch in a series of high electron mobility transistor (HEMT) structures grown by molecular beam epitaxy (MBE) on indium phosphide substrates.Five distinct types of irregularity are observed: 1) lattice warping, 2) the formation of a nonpseudomorphic layer, 3) the formation of extended arrays of linear mismatch dislocations at the interface between the substrate and a nonpseudomorphic layer, 4) the formation of oval regions of tweed-like local lattice variation imbedded among these arrays, and 5) extended tweed-like local lattice variation over large peripheral areas in which the formation of straight mismatch dislocation arrays is not observed.Warping of the lattice is found in nearly all layered structures. A distinct layer with a different lattice parameter but without visible misfit dislocations is formed with a mismatch of 0.27 %. With increase of the mismatch to 0.5 %, the other three forms of accommodation appear in distinct regions of the structure: arrays of mismatch dislocations; oval regions of tweed-like irregularity, oriented in the [011] direction; and peripheral regions of extended tweed-like local lattice variation.

Low-order, monolayer by monolayer (1×1) AlAs/GaAs superlattices grown by MBE using different growth techniques have been studied by X-ray diffractometry. High-resolution multiple-crystal diffractometry was used to study diffraction features near the [004] peaks due to the substrate and epilayers. Using this technique, we have investigated the effect of growth techniques on the strain and tilt of the superlattices. High-resolution X-ray diffraction (HRXRD) results suggest that the sample grown by migration-enhanced epitaxy (MEE) is more highly strained and has more tilt than the same superlattice sample grown using the interrupted growth (IG) technique.

Current techniques of myocardial protection during global ischemia include hypothermia, cardioplegic arrest and controlled reperfusion. To compare different types of cardioplegia and reperfusion techniques we measured the levels of adenine nucleotides and malondialdehyde (MDA, as free radical activity) in 33 patients undergoing heart surgery. The patients were randomized in three groups according to the characteristics of cardioplegia and reperfusion: cold blood cardioplegia with unmodified blood reperfusion (control group, 11 patients), crystalloid cardioplegia and reperfusion (Hôpital Lariboisière protocol, 11 patients) and crystalloid cardioplegia with allopurinol enriched blood reperfusion (Hôpital Broussais protocol, 11 patients). Myocardial biopsy specimens were obtained before cardioplegic arrest (preischemic values), at the end of ischemia and after 30 minutes of reperfusion. Biopsy specimens were analyzed by high performance liquid chromatography for levels of adenine nucleotides and MDA. In the three groups, the preischemic values of adenine nucleotides and MDA were not significantly different. For AMP and ADP concentrations neither treatment nor biopsy-time effects appeared. ATP concentration decreased significantly with biopsy-time without specific treatment effect. For MDA concentration neither treatment nor biopsy-time effects were observed. This study suggests that there is no statistically significant difference between any of the three cardioplegia and reperfusion techniques for either ATP or MDA; the three reperfusion techniques limit the free radical activity but do not prevent the fall in high energy phosphates.

The acquisition of RHEED oscillation information on (100) GaAs substrates is described for use in the growth of “lattice-matched] Iny (AlxGa1−x)1-Y As layers on (100) InP substrates with 0.52 < y < 0.53 and 0.00 < x < 1.00. The observed frequency of the RHEED oscillations on GaAs is the same as on InP, however, the measured lattice parameters of the grown layers are less than that of InP. The x-ray diffraction images show that the misfit dislocations perpendicular to the primary flats of 2” round (100) InP wafers are denser than the parallel ones. Photoluminescence (at 10K) and photoreflectance (at 300K) measurements on a composite layer structure of x=0, 0.2, 0.4, 0.6, 0.8 and 1 clearly show six distinct peaks with narrow FWHMs of less than 20 meV. The measured bandgaps increase linearly with the Al content.

In this work we examine the physical properties for the superlattice system (GaAs)n1 (AlAs)n2/GaAs(100) for low values of n1 and n2, i.e., n1 = n2 = 3, 6, 12. Normal, interrupted growth, and migration enhanced epitaxy (MEE) growth techniques were used to grow the superlattice structures in a molecular beam epitaxy system. X-ray diffraction spectra were obtained, and the major and satellite peak positions were analyzed to obtain the superlattice periodicity. An analysis of the major diffraction peaks and their associated satellites produced superlattice periodicity in good agreement with theory. Diffraction peaks were also observed in regions adjacent to the primary diffraction peaks which did not occur in the expected satellite positions. An analysis of these peaks relative to the primary peak indicate periodicities corresponding to layer thickness greater than the intended period. One possible cause for these periodicities is growth conditions that exist during the growth of the superlattice which result in the deposition of fractional monolayers. In this study we present results which suggest that an arsenic-deficient growth condition may be a contributing factor in the deposition of fractional monolayers.

We report the results of our study of controlled interface roughness in low-order GaAs/AlAs superlattices. Samples were prepared using either the interrupted growth or the migration-enhanced epitaxy (MEE) technique. The samples were prepared with m atomic planes of GaAs and m atomic planes of AlAs (m × m) per modulation wavelength and repeated p times. For this study, m = 1 or 3. The samples were studied using X-ray diffraction. The interrupted growth samples both showed a split in one diffraction line indicating layers were not of integral order while the MEE samples showed no splitting, indicating integral order layers.

From January 1986 to December 1988, 244 patients had a coronary artery revascularization at St Joseph Hospital. Four patients (1.8%) died in post operative time (less than 30 days). None died directly from cardiogenic shock. Five patients had a severe low cardiac output (2 h to 48 h post-op) and needed cardiac resuscitation. These patients were immediately taken to the operating room. The coronary bypasses were explored (2 technical errors corrected), the metabolic disorders were treated and a coronary reperfusion was done with the Buckberg's technique. All the patients could be weaned from cardiopulmonary bypass, two with intra aortic balloon pumping. One patient died of digestive complication the 10th postoperative day. The four other patients survived and are in good clinical condition. The severe low cardiac output after coronary revascularization can be reversible with resuscitation in operating room, short assistance, and coronary reperfusion.

3053 Background: We have previously shown an association between functional polymorphisms in genes involved in DNA repair and outcome in patients (pts) with H&NC. Here in we report the association ...

We report on a magneto-Raman scattering investigation of free and donor-bound electrons in GaAs/Al x Ga 1−x As quantum wells. For fields perpendicular to the layers, the spectra show intersubband transitions of photoexcited electrons and ls→ls′ donor excitations. Tilted fields lead to subband-Landau level and ls′−2p + coupling. Experimental results for the latter case agree very well with variational calculations. Data on combined intersubband-cyclotron resonances at arbitrary tilt angles are accurately described by expressions valid for parabolic wells. The parabolic approach is shown to provide a good approximation in situations where coupling to higher subbands can be neglected.

We report on a magneto-Raman scattering investigation of free and donor-bound electrons in GaAsAl x Ga 1−x As quantum wells. For fields perpendicular to the layers, the spectra show intersubband transitions of photoexcited electrons and 1s → 1s′ donor excitations. Tilted fields lead to subband-Landau level and 1s′ − 2p + coupling. Experimental results for the latter case agree very well with variational calculations. Data on combined intersubband-cyclotron resonances at arbitrary tilt angles are accurately described by expression valid for parabolic wells. The parabolic approach is shown to provide a good approximation in situations where coupling to higher subbands can be neglected.

Differential resistivity and Hall effect measurements and secondary ion mass spectrometry (SIMS) are used to study the annealing behavior of Be-implanted GaAs0.6P0.4. Results similar to that previously reported for Be-implanted GaAs are observed, including outdiffusion of Be into the Si3N4 encapsulant during 900‡C annealing of high dose implants. Nearly all (85–100%) of the Be remaining after a 900‡C, 1/2 hr anneal is electrically active. However, the electrical activation at low annealing temperatures (600–700‡C) is much lower in GaAs0.6P0.4 than in GaAs. A substantial amount of diffusion is observed even for the low fluence Be implants in GaAs0.6P0.4 annealed at 900‡C, indicating a greater dependence of the diffusion on defect-related effects in the ternary.

The performance of semiconductor devices becomes increasingly sensitive to details of the depth distribution of dopants as device dimensions are reduced. In this paper, limitations on the control of dopant distributions resulting from implantation into single‐crystal silicon due to ion channeling are examined for a range of ion atomic numbers and energies characteristic of semiconductor device fabrication. Implantation profiles were obtained by 1 MHz differential capacitance–voltage profiling and by secondary ion mass spectroscopy for silicon substrates implanted at angles from accurately channeled alignment to ’’random equivalent’’ orientation. The critical angle as calculated from an existing computer fit to the Moliere continuum potential was used to scale the angular dependence of the implantation profiles. Ion channeling is seen to have important consequences not only for the deeply penetrating regions of the dopant profile but for the near‐surface profile as well. The results of this study indicate ...

Depth profiles of aluminum and sodium implanted into silicon carbide, silicon and silicon dioxide have been measured by means of sharp resonances in the reactions 27Al(p,γ)28Si and 23Na(p,γ)24Mg. The absolute number of impurity atoms has been determined and compared with that indicated by charge integration during implantation. Adjacent areas of some specimens have been measured by the Cameca ion-beam mass spectrometer and the nuclear resonance method; results are compared. A depth resolution of less than 20 A has been demonstrated for Al very near the surface of SiC. Information concerning the migration of sodium in SiO2 under ion bombardment is presented. Depth profiles are extracted from gamma-ray yield curves taking into account the beam energy distribution, the resonance shape, the average proton energy loss in the sample and the energy loss straggling.

The effects of isothermal annealing on the profiles of heavy (4×1016 Al+/cm2 at 60 keV) implantations of Al in SiC were investigated by means of the 27Al(p,γ)28Si nuclear resonance technique. Annealing at 1400 °C for 15 min resulted in the apparent outdiffusion of about 30% of the implanted Al, an accumulation of Al at the surface, and a residual peak at the depth of the as−implanted profile. Subsequent annealing showed continued apparent outdiffusion with the release of Al from trapping sites as the rate−limiting process.

Profiles of ion-implanted Be concentrations in GaAs substrates were measured by means of the 9 Be(p, α ) 6 Li reaction and SIMS methods. A magnetic spectrometer was used to detect the α-particles in a 45° scattering geometry. Profiles obtained from the two methods were in substantial agreement.

The Raman spectra of GaAs and InP implanted with Be ions with fluences ranging from 5×1012 to 1×1016 cm−2 were investigated. A marked difference in the behavior of the TO and LO modes with respect to broadening with fluence was observed and the results indicate that this is caused by frequency dependent anharmonic damping constants. The Raman spectra of high fluence samples are interpreted in terms of disorder‐induced first‐order Raman spectra due to phonons with nonzero wave vectors. The similarities between our ‘‘Reduced Raman Spectra’’ of the disordered form and the theoretical one‐phonon density of states, are presented without introducing Gaussian broadening as suggested by earlier authors studying amorphous materials. The observations support the conclusion that the form essentially retains the short‐range order of the crystalline phase; the phonon spectrum of the crystal is largely determined only by near‐neighbor interactions; and the existence of a frequency‐dependent coupling constant for the sc...