Observation of Zero-Field Transverse Resistance in AlO_{x}/SrTiO_{3} Interface Devices.

Domain walls in AlO_{x}/SrTiO_{3} (AlO_{x}/STO) interface devices at low temperatures give a rise to a new signature in the electrical transport of two-dimensional carrier gases formed at the surfaces or interfaces of STO-based heterostructures: a finite transverse resistance observed in Hall bars in zero external magnetic field. This transverse resistance depends on the local domain wall configuration and hence changes with temperature, gate voltage, thermal cycling, and position along the sample and can even change sign as a function of these parameters. The transverse resistance is observed below ≃70 K but grows and changes significantly below ≃40 K, the temperature at which the domain walls become increasingly polar. Surprisingly, the transverse resistance is much larger in (111) oriented heterostructures in comparison to (001) oriented heterostructures. Measurements of the capacitance between the conducting interface and an electrode applied to the substrate, which reflect the dielectric constant of the STO, indicate that this difference may be related to the greater variation of the temperature-dependent dielectric constant with electric field when the electric field is applied in the [111] direction. The finite transverse resistance can be explained inhomogeneous current flow due to the preferential transport of current along domain walls that are askew to the nominal direction of the injected current.

Generating spatially entangled itinerant photons with waveguide quantum electrodynamics.

Realizing a fully connected network of quantum processors requires the ability to distribute quantum entanglement. For distant processing nodes, this can be achieved by generating, routing, and capturing spatially entangled itinerant photons. In this work, we demonstrate the deterministic generation of such photons using superconducting transmon qubits that are directly coupled to a waveguide. In particular, we generate two-photon N00N states and show that the state and spatial entanglement of the emitted photons are tunable via the qubit frequencies. Using quadrature amplitude detection, we reconstruct the moments and correlations of the photonic modes and demonstrate state preparation fidelities of 84%. Our results provide a path toward realizing quantum communication and teleportation protocols using itinerant photons generated by quantum interference within a waveguide quantum electrodynamics architecture.

Sudden cardiac death in the young in Sweden: electrocardiogram in relation to forensic diagnosis.

OBJECTIVES: To study electrocardiogram (ECG) in relation to forensic diagnosis in young persons who suffered a sudden cardiac death (SCD) in Sweden during 1992-99. DESIGN: A register study of a national database of forensic medicine in Sweden, selecting all cases of SCD 15-35 years of age. In this group, 12-lead ECGs and clinical data were searched for in military conscription and medical records. The ECGs were re-analysed and classified according to the Minnesota code criteria. SETTING: The whole nation of Sweden. SUBJECTS: Sudden cardiac death victims (66 individuals), 15-35 years of age, where it was possible to obtain an ECG recording. RESULTS: We observed major or minor ECG abnormalities in 82% of the subjects. The most common changes were T wave abnormalities (35%), ST segment changes (32%) and conduction defects (20%). The ECGs were evaluated as pathological in 50% of the cases, more often in arrhythmogenic right ventricular cardiomyopathy (88%) and hypertrophic cardiomyopathy (82%). Cardiac-related symptoms were seen in 76% of the total group and there was a family history of a similar cardiac condition in 18%. CONCLUSIONS: Pathological ECGs were common in young SCD victims, in spite of being taken many years before death. An ECG could help identify prospective victims of SCD, and should always be taken in cases with possible cardiac-related symptoms or a family history of SCD. The pathological ECGs were often found in connection with routine screening at military enlistment for men, which raises the question of a routine screening in the young, including women.

Sudden cardiac death in 15-35-year olds in Sweden during 1992-99.

OBJECTIVES: To study the incidence, pathogenesis and symptoms preceding sudden cardiovascular death amongst 15-35-year olds without substance abuse in Sweden during 1992-99. DESIGN: This was a register study of a national database of forensic medicine, Rattsbase. Clinical details were obtained from forensic, police and medical records and from interviews with family members. SETTING: The whole nation of Sweden. SUBJECTS: Individuals having suffered a sudden cardiac death. RESULTS: We found 181 cases of sudden cardiovascular death in a nationwide database, Rattsbase, in 15-35-year olds, of which 132 (73%) were male and 49 (27%) were female, and a rather stable incidence of 0.93 per 100,000 per year. Preceding symptoms were seen in half of the cases. The most common forensic diagnoses were: no structural abnormality (21.0%), coronary atherosclerosis (17.7%), dilated cardiomyopathy (12.2%), hypertrophic cardiomyopathy (10.5%) and myocarditis (10.5%). CONCLUSION: Sudden cardiovascular death was uncommon in the young, but the incidence was not decreasing. Postmortem diagnoses were often difficult to establish. There was a high frequency of structurally normal hearts. Because premortal cardiac-related symptoms are relatively common and treatment methods are developing, we should learn to recognize early symptoms of heart disease. To identify individuals at risk, further studies of preceding symptoms, life-style factors and electrocardiogram (ECG) changes are needed.

Phosphatidylethanol in post-mortem blood as a marker of previous heavy drinking.

Phosphatidylethanol (PEth) is an ethanol-phospholipid adduct, formed via non-oxidative metabolism of ethanol. PEth was measured in femoral blood from 85 consecutive forensic autopsies and was detected in 35 of the cases at concentrations ranging from 0.8 to 22.0 micromol/l. Of the PEth positive cases, 12 did not have significant levels of ethanol in the blood. Two cases (both suicides involving hanging) had detectable ethanol, but no PEth present in the blood. We conclude that measurements of PEth provide indications of previous alcohol abuse in cases where this may not otherwise be evident.

Alzheimer changes are common in aged drivers killed in single car crashes and at intersections.

With increasing age, diseases affecting the cognitive functions are more frequent. These diseases may increase the risk for fatal car crashes. We analyzed the frequency of neuropathological alterations characteristic of Alzheimer's disease (i.e. neuritic and diffuse plaques, and neurofibrillary tangles) in two association areas of the brain, parietal and frontal cerebral cortex, from 98 fatally injured aged drivers. In the age groups of 65-75 and over 75 years of age, 50% and 72% of the drivers, respectively, had neuritic plaques in either parietal and/or frontal cortex. In 14% of all killed drivers the number of neuritic plaques reached the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) age-related histologic score C, which indicates the diagnosis of Alzheimer's disease (AD), and an additional 33% had score B, which suggests the diagnosis of AD. Neuropathological AD changes were most common in the brains of drivers killed in single vehicle crashes, followed by multivehicle crashes at intersections and least common in multivehicle crashes elsewhere, but the differences did not reach statistical significance. In a great majority (80-85%) of cases the killed aged driver was the guilty party of the crash. The results imply, that incipient AD may contribute to fatal crashes of aged drivers, and therefore the forensic autopsy of these victims should include neuropathological examination.

Social interaction skills for children with autism: a script-fading procedure for beginning readers.

Engaging in spontaneous social exchanges is a central skill deficit of children with autism, and one that is often difficult to remediate. The 3 boys (ages 4, 4, and 5 years) who participated in this study had acquired small verbal repertoires, but typically spoke only when answering questions or requesting preferred edible items or toys, and did not converse with a familiar teacher during baseline. During teaching, textual cues ("Look" and "Watch me") were embedded in the youngsters' photographic activity schedules; after learning to use the scripts, the children's verbal elaborations and unscripted interactions increased and were maintained when a new recipient of interaction was introduced. After scripts were faded, unscripted interactions not only continued but also generalized to different activities that had not been the topic of teaching. The script-fading procedure enabled children with autism to converse with adults, to benefit from adults' language models, and to engage in language practice that contributes to fluency.

Procedures for teaching appropriate gestural communication skills to children with autism.

Four children with autism were taught to use gestures in combination with oral communication. Using a multiple-baseline across-responses design, intervention was introduced successively across three response categories containing gestures representative of attention-directing/getting, affective, and descriptive behavior. Although none of the participants displayed appropriate gestural and verbal responses during baseline, all participants acquired this skill with the systematic implementation of modeling, prompting, and reinforcement. Generalization measures indicated that the children learned to respond in the presence of novel stimuli and a novel setting. Social validity measures revealed that the participants' behavior appeared more socially appropriate at the completion of the study than at the start of the study, and that the participants' behavior was indistinguishable from that of their typically developing peers.

Training and generalization of affective behavior displayed by youth with autism.

The purpose of this study was to teach contextually appropriate affective behavior to 4 youths with autism. Treatment consisted of modeling, prompting, and reinforcement introduced in a multiple baseline design across response categories of affective behavior. During treatment, verbal praise and tokens were delivered contingent on appropriate affective responding during training trials. Modeling and verbal prompting were used as correction procedures. Each youth received treatment in either three or four response categories. Treatment systematically increased responding within the response categories for all 4 participants, with effects being specific to the affective response categories under treatment. Treatment effects occurred across untrained scenarios, therapists, time, and settings, suggesting that generalization had occurred.

Generalized imitation and response-class formation in children with autism.

An experimental analysis of imitation was conducted to examine the influence of response topography on generalization of imitation across three response types. Four children with autism were presented with both reinforced training trials and nonreinforced probe trials of models from vocal, toy-play, and pantomime response types. The probe trials were used to examine generalization within each response type. A multiple baseline design was used to analyze percentage of matching and nonmatching responses to models across response types. This study, the first to analyze imitative response classes in children with autism, showed that imitation generalized from reinforced training models to nonreinforced probe models within a response type, but it did not generalize across response types. Thus, functional response classes determined by topographical boundaries were exhibited within generalized imitation.

Sentence combining as a technique for increasing adjective use in writing by students with autism.

A multiple-baseline across-subjects design was used to determine whether reinforcement alone or in combination with sentence-combining exercises would increase the number of descriptive adjectives used in daily writing samples by three adolescents with autism. The cumulative number of new adjectives (adjectives never before used by a student in the entire study) was also recorded. Experimental conditions were baseline, sentence combining, and maintenance. Writing sessions consisted of a 20-min worksheet period followed by a 20-min writing period. The addition of sentence-combining exercises increased the number of adjectives in the students' writing samples. Maintenance of this increase occurred in the absence of sentence-combining lessons and in the presence of reinforcement for use of adjectives. The addition of sentence-combining exercises also increased the cumulative number of new adjectives, although new adjectives did not occasion reinforcement, and we had not expected their use to increase in students with autism without specific instruction. Maintenance of new adjective use also was demonstrated. Finally, for all three students, minimal terminable unit (T-unit) length, a measure that facilitates comparison with normative data, increased from baseline to maintenance, and independent raters judged writing samples written during maintenance as better than those written during baseline.

On systems analysis in autism intervention programs.

Although intervention technology has grown substantially during the past quarter century, the design of intervention systems has not grown apace. This paper examines organizational arrangements that enhance and diminish treatment effectiveness and argues that defining, measuring, and manipulating systemic antecedent and consequent variables are as important as assessment and intervention on an individual client's behalf.

Teaching children with autism to initiate to peers: effects of a script-fading procedure.

A script that was systematically faded from end to beginning was used to teach peer initiations about recently completed, current, and future activities. The effectiveness of the script-fading procedure was assessed via a multiple baseline design across 4 children with autism. During baseline, the children seldom initiated to peers, although all had previously acquired some functional expressive language and sometimes spontaneously addressed adults. When the script was introduced, peer initiations increased, and as the script was faded, unscripted initiations increased. With the minimal written prompts available in the final fading steps, initiations generalized to a different setting, time, teacher, and activity; and for 3 of the 4 children, peer initiations were maintained at a 2-month follow-up. After the script was faded, the participants' levels of peer initiations were within the same range as a normative sample of 3 nondisabled youngsters. The script-fading procedure enabled children with severe social and verbal deficits to practice context-specific, peer-directed generative language that was not prompted by adults or peer confederates.

Programming participation in family activities for children with autism: parents' use of photographic activity schedules.

The parents of 3 boys with autism were taught to help their children follow photographic activity schedules depicting a variety of home-living tasks. A multiple baseline across participants showed that the home-based intervention produced increases in children's engagement and social initiations and decreases in disruptive behavior, which were maintained for as long as 10 months.

Teaching children with autism to use photographic activity schedules: maintenance and generalization of complex response chains.

We used a graduated guidance procedure to teach 4 boys with autism to follow photographic activity schedules to increase on-task and on-schedule behavior. The multiple baseline across participants design included baseline, teaching, maintenance, resequencing of photographs, and generalization to novel photographs phases. The results indicated that photographic activity schedules (albums depicting after-school activities) produced sustained engagement, and skills generalized to a new sequence of photographs and to new photographs. The acquisition of schedule-following skills enabled these children with severe developmental disabilities to display lengthy response chains, independently change activities, and change activities in different group home settings in the absence of immediate supervision and prompts from others.

Experimental evaluation of polymerized Dacron grafts in the iliac position of pigs.

Three differently polymerized Dacron grafts were compared to ordinary Dacron grafts and polytetrafluoroethylene grafts in the iliac artery of pigs. The grafts were inserted end-to-side and left for 40 days. Explantation was performed after glutaraldehyde pressure fixation. Gross morphology, light microscopy, and scanning electron microscopy were used to examine the specimens. We concluded that the polymerized grafts behaved similarly to polytetrafluoroethylene grafts and had a very limited foreign body reaction. Endothelial-like cells covered most of the graft surface.

Intracapsular and atmospheric pressure in the dynamics and stability of the hip. A biomechanical study.

A cadaver study was undertaken to evaluate (a) the relations between the rotation around the axis of the neck of the femur, intracapsular effusion, and intracapsular pressure; and (b) the importance of the atmospheric pressure in stabilizing the hip joint. The following conclusions were reached: (1) There is no increase in intracapsular pressure within the normal range of rotation ("flexion") around the axis of the neck of the femur. (2) Intracapsular fluid (e.g., blood, pus, synovial edema and/or free synovial fluid) decreases this pressureless range of rotation, a likely cause of pain and subsequently flexion contractures. (3) Joint stability is primarily maintained by the atmospheric pressure within the normal range of rotation. The joint capsule is tightened only in extreme extension or flexion and contributes to stability only in these positions. (4) The traction force needed to overcome the stabilizing effect of the atmospheric pressure and thus subluxate the adult joint is approximately 200 N, in a child less, proportional to the square of the diameter of the femoral head. We also propose that intracapsular fluid makes the joint potentially unstable, a prerequisite for unfavorable mechanical cartilage load. These findings have clinical implications in synovitis, septic and juvenile arthritis, congenital dislocation of the hip, arthroplasty, and trauma.

Assessing and improving child care: a personal appearance index for children with autism.

An index of children's physical appearance and personal care was developed and used to assess youngsters with autism who lived (a) at home, (b) in an established group home, (c) in new group homes, and (d) in a large institution. Subsequently, a multiple baseline design across participants documented major changes in personal appearance and cleanliness when children moved from an institution to community-based, family-style group homes. Finally, data-based feedback generated by the appearance index was used as a training tool enabling group home staff to further improve child appearance. This research demonstrates how an evaluation instrument can be used to obtain comparative data, measure some effects of different residential placements, and provide ongoing feedback to caregivers to promote high standards of personal care among persons with severe developmental disabilities.