Spoken narrative comprehension for young adult listeners: effects of competing voices and noise

OBJECTIVE

To examine the influence of competing voices or noise on the comprehension of spoken narratives for young adults.

DESIGN

First, an intelligibility assessment of the target narratives was conducted to establish a signal-to-noise ratio ensuring accurate initial speech recognition. Then, narrative comprehension for two target types (fixed and varied target talker) was measured in four listening conditions (quiet, one-talker speech, speech babble, speech-shaped noise). After hearing target narratives in each listening condition, participants completed a visual recognition memory task that assessed the comprehension of the narrative materials at three levels of representation (surface form, propositional, event model).

STUDY SAMPLE

Seventy adults (18-32 years of age).

RESULTS

Narrative comprehension results revealed a main effect of listening condition at the event model level, indicating poorer narrative memory of described situations for all noise conditions compared to quiet. Increased positive responses to thematically consistent but situationally "wrong" memory probes drove this effect. No other significant effects were observed.

CONCLUSION

Despite near-perfect speech recognition, background noise negatively influenced aspects of spoken narrative comprehension and memory. Specifically, noise did not disrupt memory for what was said (surface form and propositional memory), but only memory for what was talked about (event model memory).

A consensus-based transparency checklist

We present a consensus-based checklist to improve and document the transparency of research reports in social and behavioural research. An accompanying online application allows users to complete the form and generate a report that they can submit with their manuscript or post to a public repository.

Three-dimensional collective charge excitations in electron-doped copper oxide superconductors

High-temperature copper oxide superconductors consist of stacked CuO₂ planes, with electronic band structures and magnetic excitations that are primarily two-dimensional^1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state^3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides^5-7 reveals their charge origin, that is, without mixing with magnetic components^5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO₂ planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems^8-12 and argued to play a substantial part in mediating high-temperature superconductivity^10-12.

Recognition without Perceptual Identification: A Measure of Familiarity?

Previous work has shown that when items in a perceptual identification task are presented too quickly to identify, participants can still discriminate between studied and unstudied items. Such recognition without perceptual identification (RWPI) has been shown to occur in a variety of situations, including the false recognition of semantic associates of studied items. The present study investigated the utility of the RWPI paradigm for isolating instances of recognition that are familiarity based from those that are recollection based. Toward this end, the magnitude of the RWPI effect was compared in item versus associative recognition and in short versus long lists. The RWPI effect was larger in item than in associative recognition, and larger with short than with long study lists. These results are interpreted within the context of a dual-process approach to recognition and support the notion that RWPI taps familiarity-based recognition.

Word Stems as Cues in Recall and Completion Tasks

Subjects tend to complete word stems to form words to which they have recently been exposed. These priming effects in word-stem completion are compared to cued recall, where subjects are asked to recall list items and are given word stems as cues. Intentionality of learning and duration of rehearsal affected recall performance but not the magnitude of priming in word-stem completion. However, cued recall and word-stem tasks did not exhibit stochastic independence: performance on one task was strongly related to performance on the other. These results are inconsistent with extreme accounts that would attribute performance on these tasks either to entirely separate systems or to an identical set of processes.

Question order bias in retrospective evaluations of item and associative recognition

Previous research has demonstrated a retrospective memory bias in metacognitive judgments regarding performance on general knowledge questions: Test-takers rate their own performance more optimistically when tests begin with easy questions than when tests begin with hard questions. An anchoring heuristic has been proposed to explain this finding, in which experience with the early questions constrains global performance evaluations of the test. In the current study we report on two experiments using tasks of item recognition and associative recognition to investigate the generality of question order bias. As predicted by an anchoring explanation, participants' estimates of performance were higher for item recognition tests beginning with easy items. However, the effect was reversed in the associative recognition task: Participants' estimates of performance were higher for tests beginning with hard items. Specific recollections, if present, may have a greater impact on test performance perception than more general global impressions.

The phase diagram of electron-doped La(2-x)Ce(x)CuO(4-δ)

Superconductivity is a striking example of a quantum phenomenon in which electrons move coherently over macroscopic distances without scattering. The high-temperature superconducting oxides (cuprates) are the most studied class of superconductors, composed of two-dimensional CuO2 planes separated by other layers that control the electron concentration in the planes. A key unresolved issue in cuprates is the relationship between superconductivity and magnetism. Here we report a sharp phase boundary of static three-dimensional magnetic order in the electron-doped superconductor La(2-x)Ce(x)CuO(4-δ), where small changes in doping or depth from the surface switch the material from superconducting to magnetic. Using low-energy spin-polarized muons, we find that static magnetism disappears close to where superconductivity begins and well below the doping level at which dramatic changes in the transport properties are reported. These results indicate a higher degree of symmetry between the electron and hole-doped cuprates than previously thought.

Experimental demonstration of superconducting critical temperature increase in electromagnetic metamaterials

A recent proposal that the metamaterial approach to dielectric response engineering may increase the critical temperature of a composite superconductor-dielectric metamaterial has been tested in experiments with compressed mixtures of tin and barium titanate nanoparticles of varying composition. An increase of the critical temperature of the order of ΔT ~ 0.15 K compared to bulk tin has been observed for 40% volume fraction of barium titanate nanoparticles. Similar results were also obtained with compressed mixtures of tin and strontium titanate nanoparticles.

Superconducting anisotropy in the electron-doped high-Tc superconductors Pr2-xCexCuO4-y

We report superconducting anisotropy measurements in the electron-doped high-Tc superconductors (HTSCs) Pr(2-x)Ce(x)C(u)O(4-y) (PCCO, x = 0.15 and 0.17) with an applied magnetic field (H0) up to 28 T. Our results show that the upper critical field [H(c2)(T)] of PCCO is highly anisotropic and as the temperature T → 0, the value of it at H0 ∥ c [H(c2,∥c)(0)] is far less than the Pauli limit. The low temperature anisotropic character of PCCO is found to be rather similar to that of hole-doped cuprate HTSCs, but apparently larger than that of typical Fe-based superconductors. This study also proves a new sensitive probe of detecting rich properties of unconventional superconductors with the use of the resonant frequency of an NMR probe circuit.

High-pressure resistivity technique for quasi-hydrostatic compression experiments

Diamond anvil cell techniques are now well established and powerful methods for measuring materials properties to very high pressure. However, high pressure resistivity measurements are challenging because the electrical contacts attached to the sample have to survive to extreme stress conditions. Until recently, experiments in a diamond anvil cell were mostly limited to non-hydrostatic or quasi-hydrostatic pressure media other than inert gases. We present here a solution to the problem by using focused ion beam ultrathin lithography for a diamond anvil cell loaded with inert gas (Ne) and show typical resistivity data. These ultrathin leads are deposited on the culet of the diamond and are attaching the sample to the anvil mechanically, therefore allowing for measurements in hydrostatic or nearly hydrostatic conditions of pressure using noble gases like Ne or He as pressure transmitting media.

Two-Fermi-surface superconducting state and a nodal d-wave energy gap of the electron-doped Sm1.85Ce0.15CuO(4-δ) cuprate superconductor

We report on laser-excited angle-resolved photoemission spectroscopy in the electron-doped cuprate Sm1.85Ce0.15CuO(4-δ). The data show the existence of a nodal hole-pocket Fermi surface both in the normal and superconducting states. We prove that its origin is long-range antiferromagnetism by an analysis of the coherence factors in the main and folded bands. This coexistence of long-range antiferrmagnetism and superconductivity implies that electron-doped cuprates are two-Fermi-surface superconductors. The measured superconducting gap in the nodal hole pocket is compatible with a d-wave symmetry.

Students' Perception of Actual, Trivial, and Inaccurate Personality Feedback

Examined the ability of college students at two levels of defensiveness to discriminate among three types of personality feedback: actual personality feedback based on the student's test scores, trivial feedback which is generally true of all students, and inaccurate feedback which was the exact opposite of the student's actual test scores. The students could reliably discriminate the three types of feedback on the dimensions of uniqueness, usefulness, accuracy, and as a source of new information about themselves. The results are discussed in the context of the Barnum literature to the effect that students can offer valid perceptions of personality descriptions of themselves.

Some Reflections on "MMPI Short Forms: A Literature Review"

Stevens and Reilley (1980) have suggested that recent changes in the methodological approaches for developing short forms of the MMPI make them an expanding and fruitful area of research. Since Stevens and Reilley did not address several important issues in the development and use of Short forms, these issues are reviewed and suggestions are presented for future research with short forms.

Orthographic neighborhood size effects and associative recognition

Three experiments on the role of orthographic distinctiveness (as measured by neighborhood size [N]) in associative recognition are reported. A mirror effect was obtained, with high-N words receiving more hits and fewer false alarms than low-N words. This pattern was replicated in Experiment 2, where participants carried out a relational orienting task. However, the high-N advantage in hit rates was eliminated in Experiment 3 when subjects carried out an item-processing orienting task. The high-N advantage in associative recognition contrasts with the low-N advantage found in item recognition. This reversal of mirror effects between item and associative recognition is empirically similar to patterns found in studies of normative word frequency.

Observation of a 500 meV collective mode in La2-xSrxCuO4 and Nd2CuO4 using resonant inelastic X-ray scattering

Utilizing resonant inelastic x-ray scattering, we report a previously unobserved mode in the excitation spectrum of La2-xSrxCuO4 and Nd2CuO4 at 500 meV. The mode is peaked around the (pi, 0) point in reciprocal space and is observed to soften, and broaden, away from this point. Samples with x=0, 0.01, 0.05, and 0.17 were studied. The new mode is found to be rapidly suppressed with increasing Sr content and is absent at x=0.17, where it is replaced by a continuum of excitations. This mode is only observed when the incident x-ray polarization is normal to the CuO planes.

Dirty superconductivity in the electron-doped cuprate Pr(2-x)Ce(x)CuO(4-delta): tunneling study

We report a tunneling study between Pr(2-x)Ce(x)CuO(4-delta) and lead as a function of doping, temperature, and magnetic field. The temperature dependence of the gap follows the BCS prediction. Our data fit a nonmonotonic d-wave order parameter for the whole doping range studied. From our data we are able to conclude that the electron-doped cuprate Pr(2-x)Ce(x)CuO(4-delta) is a weak-coupling BCS dirty superconductor.

High-field Hall resistivity and magnetoresistance of electron-doped Pr2-xCexCuO4-delta

We report resistivity and Hall effect measurements in electron-doped Pr2-xCexCuO4-delta films in magnetic field up to 58 T. In contrast to hole-doped cuprates, we find a surprising nonlinear magnetic field dependence of Hall resistivity at high field in the optimally doped and overdoped films. We also observe a crossover from quadratic to linear field dependence of the positive magnetoresistance in the overdoped films. A spin density wave induced Fermi surface reconstruction model can be used to qualitatively explain both the Hall effect and magnetoresistance.

Orthographic neighborhood size effects in recognition memory

This study argues for the importance of physical word features in recognition memory by investigating the influence of orthographic distinctiveness. Experiment 1 demonstrated a mirror effect in ayes/no recognition test by manipulating orthographic neighborhood size. Words with small neighborhoods showed more hits and fewer false alarms than did words with larger neighborhoods. Experiment 2 replicated the neighborhood size mirror effect using null pairs in a forced choice recognition test. Experiment 3 required remember/know judgments in a yes/no recognition task. Experiment 4 used the same yes/no test as did Experiment 1, adding a study task that drew attention away from orthographic information in the study list. The mirror pattern disappeared with the addition of the study task.

Tunneling into the normal state of Pr2-xCexCuO4

The temperature dependence of the tunneling conductance was measured for various doping levels of Pr(2-x)CexCuO4 using planar junctions. A normal state gap is seen at all doping levels studied, x=0.11 to x=0.19. We find it to vanish above a certain temperature T*. T* is greater than T(c) for the underdoped region and it follows T(c) on the overdoped side. This behavior suggests finite pairing amplitude above T(c) on the underdoped side.

Origin of the anomalous low temperature upturn in the resistivity of the electron-doped cuprate superconductors

The temperature, doping, and field dependences of the magnetoresistance (MR) in Pr2-xCexCuO4-delta films are reported. We distinguish between orbital MR, found when the magnetic field is applied perpendicular to the ab planes, and the nearly isotropic spin MR. The latter, the major MR effect in the superconducting samples, appears in the region of the doping-temperature phase diagram where drho/dT<0, or an upturn in the resistivity appears. We conclude that the upturn originates from spin scattering processes.

Anomalous change in the field dependence of the electronic specific heat of an electron-doped cuprate superconductor

We present specific heat measurements on Pr(2-x)CexCuO(4-delta) single crystals which show an unexpected change in the field dependence of the electronic specific heat (Cel) from linear at T = 2 K to nonlinear at T > or = 3 K. We consider several possible explanations for this change and propose, as a possible interpretation, a phase transition in the symmetry of the order parameter from nodal (e.g., d wave) at T > or = 3 K to gapped (e.g., s wave) at T = 2 K. Such a phase transition could be an explanation for the previous conflicting experimental results on the pairing symmetry in the electron-doped cuprates.

Co-occurrence of superparamagnetism and anomalous hall effect in highly reduced cobalt-doped rutile TiO2-delta films

We report a detailed magnetic and structural analysis of highly reduced Co doped rutile TiO(2-delta) films displaying an anomalous Hall effect (AHE). The temperature and field dependence of magnetization, and transmission electron microscopy, clearly establish the presence of nanosized superparamagnetic cobalt clusters of approximately 8-10 nm size in the films at the interface. The co-occurrence of superparamagnetism and AHE raises questions regarding the use of the AHE as a test of the intrinsic nature of ferromagnetism in diluted magnetic semiconductors.

Evidence for a quantum phase transition in Pr2-xCe(x)CuO4-delta from transport measurements

The doping and temperature dependences of the Hall coefficient, R(H), and ab-plane resistivity in the normal state down to 350 mK is reported for oriented films of the electron-doped high-T(c) superconductor Pr(2-x)Ce(x)CuO(4-delta). The doping dependences of beta (rho=rho(0)+ATbeta) and R(H) (at 350 mK) suggest a quantum phase transition at a critical doping near x=0.165.

True and false memory in the absence of perceptual identification

Two experiments are reported in which, after attempting to identify a briefly flashed, masked test word, participants were asked to rate the likelihood that it had been presented in an earlier study list. Even when people were unable to identify such items, they demonstrated an ability to discriminate between those that were studied and those that were not studied; ratings given to studied items were significantly higher than ratings given to nonstudied items. This effect does not appear to be a data-driven phenomenon. In Experiment 1 it was found when the presentation modality was changed from study to test. In Experiment 2 false memory for unidentified items that were related to studied items was shown.

Inhomogeneous electronic structure probed by spin-echo experiments in the electron doped high-Tc superconductor Pr1.85Ce0.15CuO4-y

63Cu nuclear magnetic resonance spin-echo decay rate (T-12) measurements are reported for the normal and superconducting states of a single crystal of Pr(1.85)Ce(0.15)CuO(4-y) in a magnetic field B(0)=9 T over the temperature range 2<T<200 K. The spin-echo decay rate is temperature dependent for T<55 K and has a substantial dependence on the radio frequency (rf) pulse parameters below T approximately 25 K. This dependence indicates that T-12 is strongly effected by a local magnetic field distribution that can be modified by the rf pulses, including ones that are not at the nuclear Larmor frequency. The low-temperature results are consistent with the formation of a static inhomogeneous electronic structure that couples to the rf fields of the pulses.

Does recognition of single words predict recognition of two?

Participants studied a list of words, presented 1 at a time. When they were tested on pairs of words and asked to indicate whether both had occurred in the list, they gave more positive responses than would be expected on the basis of results from participants tested 1 word at a time. When participants were asked whether either member of a test pair had been shown on the study list, they gave positive responses less often than expected. When participants were asked to indicate how many words in a test pair came from the study list, they answered "2" more often and "1" less often than would be expected on the basis of results from single-item recognition. Accuracy was not affected by testing items in pairs.

Superconductivity and field-induced magnetism in Pr2-xCexCuO4 single crystals

We report muon-spin rotation and relaxation (muSR) measurements on single crystals of the electron-doped high-T(c) superconductor Pr2-xCexCuO4. In a zero external magnetic field, superconductivity is found to coexist with dilute Cu spins that are static on the muSR time scale. In an applied field, we observe a mu(+)-Knight shift that is primarily due to the magnetic moment induced on the Pr ions. Below the superconducting transition temperature T(c), an additional source of local magnetic field appears throughout the volume of the sample. This finding is shown to be consistent with field-induced antiferromagnetic ordering of the Cu spins. Measurements of the temperature dependence of the in-plane magnetic penetration depth lambda(ab) in the vortex state are also presented.

High temperature ferromagnetism with a giant magnetic moment in transparent co-doped SnO(2-delta)

The occurrence of room temperature ferromagnetism is demonstrated in pulsed laser deposited thin films of Sn(1-x)Co(x)O(2-delta) (x<0.3). Interestingly, films of Sn(0.95)Co(0.05)O(2-delta) grown on R-plane sapphire not only exhibit ferromagnetism with a Curie temperature close to 650 K, but also a giant magnetic moment of 7.5+/-0.5 micro(B)/Co, not yet reported in any diluted magnetic semiconductor system. The films are semiconducting and optically highly transparent.

Direct Observation of Percolation in a Manganite Thin Film

Upon cooling, the isolated ferromagnetic domains in thin films of La0.33Pr0.34Ca0.33MnO3 start to grow and merge at the metal-insulator transition temperature TP1, leading to a steep drop in resistivity, and continue to grow far below TP1. In contrast, upon warming, the ferromagnetic domain size remains unchanged until near the transition temperature. The jump in the resistivity results from the decrease in the average magnetization. The ferromagnetic domains almost disappear at a temperature TP2 higher than TP1, showing a local magnetic hysteresis in agreement with the resistivity hysteresis. Even well above TP2, some ferromagnetic domains with higher transition temperatures are observed, indicating magnetic inhomogeneity. These results may shed more light on the origin of the magnetoresistance in these materials.

Evidence of a d- to s-wave pairing symmetry transition in the electron-doped cuprate superconductor Pr(2-x)CexCuO4

We present point contact spectroscopy (PCS) data for junctions between a normal metal and the electron-doped cuprate superconductor Pr(2-x)CexCuO4 (PCCO). For the underdoped compositions of this cuprate ( x approximately 0.13) we observe a peak in the conductance-voltage characteristics of the point contact junctions. The shape and magnitude of this peak suggest the presence of Andreev bound states at the surface of underdoped PCCO which is evidence for a d-wave pairing symmetry. For overdoped PCCO ( x approximately 0.17) the PCS data do not show any evidence of Andreev bound states at the surface suggesting an s-wave pairing symmetry.

Nonmonotonic d(x(2)-y(2)) superconducting order parameter in Nd2-xCexCuO4

Low energy polarized electronic Raman scattering of the electron-doped superconductor Nd2-x Ce x CuO4 ( x = 0.15, T(c) = 22 K) has revealed a nonmonotonic d(x(2)-y(2)) superconducting order parameter. It has a maximum gap of 4.4k(B)T(c) at Fermi surface intersections with an antiferromagnetic Brillouin zone (the "hot spots") and a smaller gap of 3.3k(B)T(c) at fermionic Brillouin zone boundaries. The gap enhancement in the vicinity of the hot spots emphasizes the role of antiferromagnetic fluctuations and the similarity in the origin of superconductivity for electron- and hole-doped cuprates.

Conidial movement of nontoxigenic Aspergillus flavus and A. parasiticus in peanut fields following application to soil

The use of nontoxigenic strains of Aspergillus flavus and A. parasiticus in biological control effectively reduces aflatoxin in peanuts when conidium- producing inoculum is applied to the soil surface. In this study, the movement of conidia in soil was examined following natural rainfall and controlled precipitation from a sprinkler irrigation system. Conidia of nontoxigenic A. flavus and A. parasiticus remained near the soil surface despite repeated rainfall and varying amounts of applied water from irrigation. In addition, rainfall washed the conidia along the peanut furrows for up to 100 meters downstream from the experimental plot boundary. The dispersal gradient was otherwise very steep upstream along the furrows and in directions perpendicular to the peanut rows. The retention of biocontrol conidia in the upper soil layers is likely important in reducing aflatoxin contamination of peanuts and aerial crops such as corn and cottonseed.

Paradoxical effects of presentation modality on false memory

Two experiments are reported in which the effects of presentation modality on false memory in recall and recognition are studied. False recall and recognition of critical targets are lower for non-presented items related to a study list when that study list is presented visually than when presented auditorily. This pattern of low levels of false memory for critical targets holds even when participants read the visually presented study items aloud. These results suggest that recollection of visual detail plays a role in the prevention of false memory. However, both the hit rates (true memory) and the false-alarm rates to weakly related distractors (non-critical targets) were higher for visual presentation than for auditory presentation, suggesting that more than one mechanism may underlie false recognition.

Breakdown of Fermi-liquid theory in a copper-oxide superconductor

The behaviour of electrons in solids is well described by Landau's Fermi-liquid theory, which predicts that although electrons in a metal interact, they can still be treated as well defined fermions, which are called 'quasiparticles'. At low temperatures, the ability of quasiparticles to transport heat is given strictly by their ability to transport charge, as described by a universal relation known as the Wiedemann-Franz law, which hitherto no material has been known to violate. High-temperature superconductors have long been thought to fall outside the realm of Fermi-liquid theory, as suggested by several anomalous properties, but this has yet to be shown conclusively. Here we report an experimental test of the Wiedemann-Franz law in the normal state of a copper-oxide superconductor, (Pr,Ce)2CuO4, which reveals that the elementary excitations that carry heat in this material are not fermions. This is compelling evidence for the breakdown of Fermi-liquid theory in high-temperature superconductors.

High resolution study of permanent photoinduced reflectivity changes and charge-order domain switching in Bi(0.3)Ca(0.7)MnO(3)

We report near-field and far-field optical microscopic studies of photoinduced effects in charge-ordered Bi(0.3)Ca(0.7)MnO(3). Unlike previously reported transient photoinduced effects in manganites, we have observed permanent reflectivity changes following local sample illumination with 488 nm light. High-resolution images of exposed regions reveal optical contrast on a submicrometer scale. This observation indicates that photonic band-gap structures may be created using holographic recording in manganites. We also present images of photoinduced charge-order domain switching in Bi(0.3)Ca(0.7)MnO(3).

Structurally modulated magnetic properties in the A(3)MnRu(2)O(9) phases (A = Ba, Ca): the role of metal-metal bonding in perovskite-related oxides

Ca(3)MnRu(2)O(9) and Ba(3)MnRu(2)O(9) were synthesized from transition metal dioxides and alkaline earth metal carbonates at 1100-1300 degrees C. Ca(3)MnRu(2)O(9) adopts the prototypical GdFeO(3)-type perovskite structure with Mn and Ru statistically disordered over the single metal atom site. The susceptibility shows Curie-Weiss behavior above 240 K with mu(eff) = 3.14 micro(B)/metal atom, which is in excellent agreement with the expected spin-only moment of 3.20 micro(B). Below 150 K, the compound shows spin-glass-like short-range ferrimagnetic correlations. The high-temperature region of the electrical resistivity reveals a small activation energy of 17(1) meV whereas the low-temperature region is nonlinear and does not fit a variable range hopping model. Ba(3)MnRu(2)O(9) crystallizes in the 9-layer BaRuO(3)-type structure containing M(3)O(12) face-shared trioctahedral clusters in which Mn and Ru are statistically disordered. Ba(3)MnRu(2)O(9) shows nonlinear reciprocal susceptibility at all temperatures and is described by a variable-spin cluster model with an S = (1)/(2) ground state with thermally populated excited states. The low spin value of this system (S = (1)/(2)) is attributed to direct metal-metal bonding. Below 30 K, the compound shows short-range magnetic correlations and spin-glass-like behavior. The high-temperature region of the electrical resistivity indicates a small activation energy of 8.8(1) meV whereas the low-temperature region is nonlinear. The importance of metal-metal bonding and the relationships to other related compounds are discussed.

The utility of MMPI-2 suicide items for assessing suicidal potential: development of a Suicidal Potential Scale

The assessment of suicidal potential is one of the most challenging and stress-inducing tasks facing clinicians. Studies that have attempted to identify specific MMPI codetypes, scales, or individual items predictive of completed suicide have produced inconsistent findings. This study focused on the relationship between the six most direct MMPI-2 suicide items (Items 150, 303, 506, 520, 524, and 530) and verbally reported history of suicidal ideation and behavior among a sample of psychotherapy outpatients (n =116). These six MMPI-2 suicide items provided valuable information regarding suicidal ideation and behavior above and beyond that of verbal self-report. These items were grouped together to create a single scale, the Suicidal Potential Scale (SPS) that manifested strong internal consistency. The SPS provides the clinician with a reliable method of assessing for self-reported suicidal ideation and behavior.

Effects of familiarity level and repetition on recognition accuracy

Theories of recognition memory based on signal detection theory posit that a recognition decision is similar to a psychophysical judgment. Like a judgment of stimulus brightness or loudness, a recognition judgment is based on the value of a unidimensional signal computed for the test item. This signal has been called the strength or familiarity value. One prediction of these models is that the ability to discriminate between a studied and nonstudied test item depends on the ability to detect the difference in their familiarities. This ability in turn is influenced by the items' familiarity levels; discrimination should become more difficult as the familiarity of both items increases. This prediction was supported in 3 experiments using a forced-choice procedure. Also, accuracy was higher when the list contained repeated items rather than a comparable number of distinct items.

Electroresistance and electronic phase separation in mixed-valent manganites

The sensitivity of transport in colossal magnetoresistance (CMR) manganites to external electric and magnetic fields is examined using field effect configurations with La(0.7)Ca(0.3)MnO(3) (LCMO), Na(0.7)Sr(0.3)MnO(3), La(0.7)Ba(0.3)MnO(3), and La(0.5)Ca(0.5)MnO(3) (0.5-doped LCMO) channels, and ferroelectric PbZr(0.2)Ti(0.8)O(3) (PZT) or dielectric (SrTiO(3)) gates. A large electroresistance (ER) of approximately 76% at 4 x 10(5) V/cm is found in LCMO with PZT-ferroelectric gate, but the magnitude of the effect is much smaller (a few percent) in the other three channels. The ER and CMR effects are remarkably complimentary. The size and systematics of the effect strongly favor a percolative phase separation picture.

An evaluation of the usefulness of the MMPI-2 F(p) scale

The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) F(p) scale was developed by Arbisi and Ben-Porath (1995) by identification of 27 items endorsed by fewer than 20% of individuals in both normal and psychiatric samples. The F(p) scale was designed for applications in settings characterized by high base rates of serious psychopathology, such as psychiatric inpatient units, and is proposed as a useful scale in discriminating overreported protocols from those produced by patients with serious psychopathology. In this study we investigated the characteristics of this scale in a sample of 617 psychiatric inpatients who responded to the MMPI-2 under standard conditions, and 203 overreported protocols derived in research studies conducted with normal adult participants instructed to simulate various forms of serious psychopathology. Results of this study are consistent with prior reports of a relatively low frequency of item endorsement for F(p) scale items in psychiatric samples, and intercorrelations between the F(p) scale and the MMPI-2 basic clinical scales in clinical samples that are generally lower than those produced between either F or Fb and the basic clinical scales. However, this intercorrelational pattern between F(p) and the MMPI-2 basic scales was not as consistent for the overreported sample. Additionally, the F(p) scale appears to be effective in discriminating overreported from accurate MMPI-2 protocols, with some evidence that the optimal cutting scores for this and other MMPI-2 infrequency scales may differ as a function of gender. Finally, these findings do not show clear evidence of improved group prediction derived from the use of the F(p) scale in contrast to results obtainable through the use of the MMPI-2 F scale.

Memory for unidentified items: evidence for the use of letter information in familiarity processes

Participants can give accurate recognition judgments to word fragments that they are unable to complete. In three experiments, the generality of this finding was examined across tasks. Accurate memory judgments in the absence of identification were obtained in item recognition and judgments of presentation frequency but not in associative recognition or list discrimination. The former two tasks are thought to involve the use of familiarity; the latter two are thought to rely on recollection. The present results are consistent with the claim that recognition without identification reflects familiarity processes.

Memory for detail in item versus associative recognition

Some studies have shown that, although repetition increases the familiarity of a stimulus, it does not improve memory for its details. Because memory for associative information is thought to require memory for the details of study presentation, the effects of repetition on associative recognition were examined in the present study. The pattern of results was similar to that found for the recognition of item details: Repetition increased the familiarity of the individual items within each pair to a greater extent than it improved memory for their specific pairings.

Assessing depression with the MMPI and MMPI-2

The usefulness of the MMPI (Hathaway & McKinley, 1951 ) and MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) for diagnosing and assessing symptomatic depression has been the subject of considerable debate for a number of years. In this article, we review the relative contributions of the MMPI and MMPI-2 clinical and content scales in predicting depression. Positive predictive power, negative predictive power, and overall classification rate were computed for Scale 2 (D) of the MMPI and MMPI-2 and the Depression content scale (DEP) of the MMPI-2. Scale 2 (D) of both the MMPI and MMPI-2 appears to be moderately accurate in predicting depression. Although some studies suggest that the content scale DEP provides incremental validity over Scale 2 (D) of the MMPI-2, the results of this review indicate that the content scale DEP of the MMPI-2 does not exceed the diagnostic efficiency of Scale 2 in predicting depression.

Evidence for nodal quasiparticles in electron-doped cuprates from penetration depth measurements

The in-plane magnetic penetration depth, lambda(T), was measured down to 0.4 K in single crystals of electron-doped superconductors, Pr(1.85)Ce(0.15)CuO(4-delta) (PCCO) and Nd(1.85)Ce(0.15)CuO(4-delta) (NCCO). In PCCO, the superfluid density varies as T2 from 0.025 up to roughly 0.3T/T(c) suggestive of a d-wave state with impurities. In NCCO, lambda(T) shows a pronounced upturn for T<4 K due to the paramagnetic contribution of Nd3+ ions. Fits to an s-wave order parameter over the standard BCS range (T/T(c) = 0.32) limit any gap to less than Delta(min)(0)/T(c) = 0.57 in NCCO. For PCCO, the absence of paramagnetism permits a lower temperature fit and yields an upper limit of Delta(min)(0)/T(c) = 0.2.

Microwave electrodynamics of electron-doped cuprate superconductors

We report microwave cavity perturbation measurements of the temperature dependence of the penetration depth, lambda(T), and conductivity, sigma(T) of Pr(2-x)Ce(x)CuO(4-delta) (PCCO) crystals, as well as parallel-plate resonator measurements of lambda(T) in PCCO thin films. Penetration depth measurements are also presented for a Nd(2-x)Ce(x)CuO(4-delta) (NCCO) crystal. We find that Deltalambda(T) has a power-law behavior for T<T(c)/3, and conclude that the electron-doped cuprate superconductors have nodes in the superconducting gap. Furthermore, using the surface impedance, we have derived the real part of the conductivity, sigma(1)(T), below T(c) and found a behavior similar to that observed in hole-doped cuprates.