Multiple solitary-waves due to second harmonic generation in quadratic media

A detailed mathematical analysis is undertaken of solitary wave solutions of a system of coupled NLS equations describing second harmonic generation in optical materials with (2) nonlinearity. The so called bright-bright case is studied exclusively. The system depends on a single dimensionless parameter ff which includes both wave and material properties. Using variational methods, the first rigorous mathematical proof is given that at least one solitary wave exists for all positive ff. Recently bound states (multi-pulsed solitary waves) have been found numerically. Using numerical continuation, the region of existence of these solutions is revealed to be ff 2 (0; 1) and the bifurcations occuring at the two extremes of this interval are uncovered

Assessment of the dysexecutive syndrome in schizophrenia

Background. Cognitive neuropsychological theories hypothesize a role for frontal lobe executive deficits in the aetiology of schizophrenic symptoms. The study examined the performance of a schizophrenic group on the Behavioural Assessment of the Dysexecutive Syndrome (BADS), a test battery which assesses the 'everyday' difficulties associated with the dysexecutive syndrome. Performance of the schizophrenics was contrasted with that of brain injured and healthy volunteer groups. Methods. Matched groups of 31 schizophrenic patients, 35 patients-with brain injuries and 26 healthy volunteers were administered the BADS. Patients were also given tests of general intelligence and memory. Patients and their relatives/carers also completed a questionnaire rating day-to-day failures of executive functioning. Results. Schizophrenic and brain-injured patients showed impairment on the BADS, compared to healthy controls. There were no significant differences between the two patient groups. Significant impairment was found in a subgroup of 16 schizophrenics who showed otherwise intact general intellectual functioning, suggesting the existence of a specific executive deficit. Among the schizophrenic patient group there was evidence of a dissociation between executive and memory impairments. A significant correlation existed between performance on the BADS and relatives ratings of executive problems for the brain injured group, but not for the schizophrenic group. Conclusions. The BADS is a useful tool for identifying executive deficits in people with a diagnosis of schizophrenia, especially those who are otherwise generally intellectually intact. This is particularly important in the context of rehabilitation and community transition programmes.published_or_final_versio

Multiplicity results for a class of asymmetric weakly coupled systems of second-order ordinary differential equations

We prove the existence and multiplicity of solutions to a two-point boundary value problem associated to a weakly coupled system of asymmetric second-order equations. Applying a classical change of variables, we transform the initial problem into an equivalent problem whose solutions can be characterized by their nodal properties. The proof is developed in the framework of the shooting methods and it is based on some estimates on the rotation numbers associated to each component of the solutions to the equivalent system

Language abnormality in deaf people with schizophrenia: a problem with classifiers

Introduction: Although there is evidence for language abnormality in schizophrenia, few studies have examined sign language in deaf patients with the disorder. This is of potential interest because a hallmark of sign languages is their use of classifiers (semantic or entity classifiers), a reference-tracking device with few if any parallels in spoken languages. This study aimed to examine classifier production and comprehension in deaf signing adults with schizophrenia. Method: Fourteen profoundly deaf signing adults with schizophrenia and 35 age- and IQ-matched deaf healthy controls completed a battery of tests assessing classifier and noun comprehension and production. Results: The patients showed poorer performance than the healthy controls on comprehension and production of both nouns and entity classifiers, with the deficit being most marked in the production of classifiers. Classifier production errors affected handshape rather than other parameters such as movement and location. Conclusions: The findings suggest that schizophrenia affects language production in deaf patients with schizophrenia in a unique way not seen in hearing patients

Teasing Apart the Impact of Illness and IQ on Functional Neuroimaging Findings in Schizophrenia

Schizophrenia is a major psychiatric disorder associated with cognitive impairment. Functional brain imaging (fMRI) studies of schizophrenia patients reveal a complex pattern of brain differences in the prefrontal cortex. Both decreased (hypofrontality) and increased (hyperfrontality) activity have been reported in patients – inconsistencies that this paper argues could be explained by differences in IQ between patients and healthy controls. This study demonstrates a novel method to tease apart IQ and schizophrenia effects on brain activity. Twelve schizophrenia patients were matched to twelve healthy controls matched to patients’ estimated (premorbid) IQ before their illness, and twelve healthy controls matched to patients’ measured current IQ. All participants performed an executive function event-related fMRI task. Schizophrenia patients’ mean behavioral scores fell numerically between those of both control groups, and did not differ significantly from either group. Two distinct patterns of brain activity were found that were consistent with an effect due to either IQ impairment or schizophrenia diagnosis. Schizophrenia patients’ relatively reduced activity in middle/superior frontal (BA6/BA8) regions was related to their schizophrenia diagnosis, whereas their relatively increased activity in inferior frontal (BA44/45) and left middle frontal (BA8/9) regionsrelated instead to their current IQ impairment. These findings indicate that some fMRI differences reported in schizophrenia patients are artefacts of IQ matching. After removing the IQ confounds, schizophrenia was associated with lateral frontal hypoactivations and medial frontal failure of deactivation. This paper proposes a method to address IQ matching-related issues when studying populations where their illness involves cognitive deterioration

Atomic and electronic structure of twin growth defects in magnetite

We report the existence of a stable twin defect in Fe3O4 thin films. By using aberration corrected scanning transmission electron microscopy and spectroscopy the atomic structure of the twin boundary has been determined. The boundary is confined to the (111) growth plane and it is non-stoichiometric due to a missing Fe octahedral plane. By first principles calculations we show that the local atomic structural configuration of the twin boundary does not change the nature of the superexchange interactions between the two Fe sublattices across the twin grain boundary. Besides decreasing the half-metallic band gap at the boundary the altered atomic stacking at the boundary does not change the overall ferromagnetic (FM) coupling between the grains

Atomic and electronic structure of twin growth defects in magnetite

We report the existence of a stable twin defect in Fe3O4 thin films. By using aberration corrected scanning transmission electron microscopy and spectroscopy the atomic structure of the twin boundary has been determined. The boundary is confined to the (111) growth plane and it is non-stoichiometric due to a missing Fe octahedral plane. By first principles calculations we show that the local atomic structural configuration of the twin boundary does not change the nature of the superexchange interactions between the two Fe sublattices across the twin grain boundary. Besides decreasing the half-metallic band gap at the boundary the altered atomic stacking at the boundary does not change the overall ferromagnetic (FM) coupling between the grains

Twisted fallopian tube in pregnancy: a case report

BACKGROUND: Isolated twisted fallopian tube is an uncommon event, isolated twisted fallopian tube in pregnancy is also very rare. The diagnosis is often difficult and established during the operation. The right fallopian tube is most common affected. CASE PRESENTATION: We report an uncommon twisted left fallopian tube in pregnancy. A 34-year-old G(3)P(2) 28 weeks pregnant woman presented with acute left lower abdominal pain. The clinical and ultrasonographic findings led to diagnosis of twisted left ovarian cyst. Emergency exploratory laparotomy was performed. A twisted left fallopian tube and paratubal cyst was noted and left salpingectomy was performed. The postoperative course was uneventful and the pregnancy continued until term without complication. CONCLUSIONS: Although isolated twisted fallopian tube during pregnancy is very rare, it should be included in the differential diagnosis of acute abdomen in pregnancy. Early surgical intervention will decrease obstetric morbidity and may allow preservation of the fallopian tube

Targeted Disruption of the Low-Affinity Leukemia Inhibitory Factor-Receptor Gene Causes Placental, Skeletal, Neural and Metabolic Defects and Results in Perinatal Death

The low-affinity receptor for leukemia inhibitory factor (LIFR)* interacts with gp130 to induce an intracellular signal cascade, The LIFR-gp130 heterodimer is implicated in the function of diverse systems, Normal placentation is disrupted in LIFR mutant animals, which leads to poor intrauterine nutrition but allows fetuses to continue to term. Fetal bone volume is reduced greater than three-fold and the number of osteoclasts is increased six-fold, resulting in severe osteopenia of perinatal bone. Astrocyte numbers are reduced in the spinal cord and brain stem. Late gestation fetal livers contain relatively high stores of glycogen, indicating a metabolic disorder. Hematologic and primordial germ cell compartments appear normal. Pleiotropic defects in the mutant animals preclude survival beyond the day of birth