4,004 research outputs found
High lying E0 strength in C-12
Journals published by the American Physical Society can be found at http://publish.aps.org/The excitation region in C-12 from 7 MeV<E-x<60 MeV was studied with inelastic scattering of 240-MeV alpha particles at small angles including 0 degrees where E0 strength is enhanced. The strengths of known 0(+) states at E-x = 7.655 MeV and E-x = 10.3 MeV were obtained and E0 strength was observed to be distributed between E-x = 14 MeV and E-x = 30 MeV with a centroid of 21.5 +/- 0.4 MeV and an ms width of 3.1 +/- 0.2 MeV containing 14.5 +/- 4.0% of the isoscalar E0 energy-weighted sum rule. Angular distributions and strengths of the E-x =4.439 MeV 2(+), 9.641 MeV 3(-), and 10.844 MeV 1(-) states were also obtained. [S0556-2813(98)05704-5]
Isoscalar electric multipole strength in C-12
Journals published by the American Physical Society can be found at http://publish.aps.org/The excitation region in C-12 below E-x=45 MeV was studied using 240 MeV alpha-particle scattering. Elastic scattering was measured from theta(c.m.)=3.8degrees to 49.4degrees and density dependant folding optical model parameters were obtained. Inelastic scattering to the 4.44 MeV 2(+), 7.65 MeV 0(+), 9.64 MeV 3(-), 10.3 MeV 0(+), and 10.84 MeV 1(-) states was measured and B(EL) values obtained. Inelastic scattering exciting C-12 to 10 MeVless than or equal toE(x)less than or equal to12.5 MeV was measured from 1.4degreesless than or equal totheta(c.m.)less than or equal to10degrees and to 12.5 MeVless than or equal toE(x)less than or equal to45 MeV from 1.4degreesless than or equal totheta(c.m.)less than or equal to16degrees and E0, E1, E2, and E3 strength distributions were obtained. Strength was identified corresponding to 27+/-5, 78+/-9, and 51+/-7% of the isoscalar E0, E1, and E2 energy weighted sum rule (EWSR), respectively, with centroids of 21.9+/-0.3, 27.5+/-0.4, and 22.6+/-0.5 MeV and rms widths of 4.8+/-0.5, 7.6+/-0.6, and 6.8+/-0.6 MeV. Less than 7% of the E3 EWSR strength was identified
On the Computational Complexity of Vertex Integrity and Component Order Connectivity
The Weighted Vertex Integrity (wVI) problem takes as input an -vertex
graph , a weight function , and an integer . The
task is to decide if there exists a set such that the weight
of plus the weight of a heaviest component of is at most . Among
other results, we prove that:
(1) wVI is NP-complete on co-comparability graphs, even if each vertex has
weight ;
(2) wVI can be solved in time;
(3) wVI admits a kernel with at most vertices.
Result (1) refutes a conjecture by Ray and Deogun and answers an open
question by Ray et al. It also complements a result by Kratsch et al., stating
that the unweighted version of the problem can be solved in polynomial time on
co-comparability graphs of bounded dimension, provided that an intersection
model of the input graph is given as part of the input.
An instance of the Weighted Component Order Connectivity (wCOC) problem
consists of an -vertex graph , a weight function ,
and two integers and , and the task is to decide if there exists a set
such that the weight of is at most and the weight of
a heaviest component of is at most . In some sense, the wCOC problem
can be seen as a refined version of the wVI problem. We prove, among other
results, that:
(4) wCOC can be solved in time on interval graphs,
while the unweighted version can be solved in time on this graph
class;
(5) wCOC is W[1]-hard on split graphs when parameterized by or by ;
(6) wCOC can be solved in time;
(7) wCOC admits a kernel with at most vertices.
We also show that result (6) is essentially tight by proving that wCOC cannot
be solved in time, unless the ETH fails.Comment: A preliminary version of this paper already appeared in the
conference proceedings of ISAAC 201
Isoscalar giant resonances in Si-28 and the mass dependence of nuclear compressibility
Journals published by the American Physical Society can be found at http://publish.aps.org/The giant resonance region from 8 MeV < E-x < 55 MeV in Si-28 has been studied with inelastic scattering of 240 MeV alpha particles at small angles including 0degrees. Strength corresponding to 81 +/- 10%, 68 +/- 9%, and 15 +/-4% of the isoscalar E0, E2, and E1 sum rules, respectively, was identified with centroids of 21.25 +/-0.38 MeV, 18.54 +/- 0.25 MeV, 19.15 +/- 0.60 MeV, and rms widths of 6.4 +/- 0.6 MeV, 4.7 +/- 0.6 MeV, and 6.9 +/- 0.7 MeV. The mass dependence of the compression modulus of finite nuclei is shown to be reasonably well reproduced from A = 24 to 208 in relativistic mean field calculations with the NLC interaction having K-nm 5225 MeV and in nonrelativistic calculations with the RATP interaction having K-nm 5240 MeV
Long term survivors with metastatic pancreatic adenocarcinoma treated with gemcitabine: a retrospective analysis
<p>Abstract</p> <p>Background</p> <p>Metastatic pancreatic adenocarcinoma has a short median overall survival (OS) of 5–6 months. However, a subgroup of patients survives more than 1 year. We analyzed the survival outcomes of this subgroup and evaluated clinical and pathological factors that might affect survival durations.</p> <p>Methods</p> <p>We identified 20 patients with metastatic or recurrent pancreatic adenocarcinoma who received single-agent gemcitabine and had an OS longer than 1 year. Baseline data available after the diagnosis of metastatic or recurrent disease was categorized as: 1) <it>clinical/demographic data </it>(age, gender, ECOG PS, number and location of metastatic sites); 2) <it>Laboratory data </it>(Hematocrit, hemoglobin, glucose, LDH, renal and liver function and CA19-9); 3) <it>Pathologic data </it>(margins, nodal status and grade); 4) <it>Outcomes data </it>(OS, Time to Treatment Failure (TTF), and 2 year-OS). The lowest CA19-9 levels during treatment with gemcitabine were also recorded. We performed a univariate analysis with OS as the outcome variable.</p> <p>Results</p> <p>Baseline logarithm of CA19-9 and total bilirubin had a significant impact on OS (HR = 1.32 and 1.31, respectively). Median OS and TTF on gemcitabine were 26.9 (95% CI = 18 to 32) and 11.5 (95% CI = 9.0 to 14.3) months, respectively. Two-year OS was 56.4%, with 7 patients alive at the time of analysis.</p> <p>Conclusion</p> <p>A subgroup of patients with metastatic pancreatic cancer has prolonged survival after treatment with gemcitabine. Only bilirubin and CA 19-9 levels were predictive of longer survival in this population. Further analysis of potential prognostic and predictive markers of response to treatment and survival are needed.</p
Physiological phenotyping of dementias using emotional sounds.
INTRODUCTION: Emotional behavioral disturbances are hallmarks of many dementias but their pathophysiology is poorly understood. Here we addressed this issue using the paradigm of emotionally salient sounds. METHODS: Pupil responses and affective valence ratings for nonverbal sounds of varying emotional salience were assessed in patients with behavioral variant frontotemporal dementia (bvFTD) (n = 14), semantic dementia (SD) (n = 10), progressive nonfluent aphasia (PNFA) (n = 12), and AD (n = 10) versus healthy age-matched individuals (n = 26). RESULTS: Referenced to healthy individuals, overall autonomic reactivity to sound was normal in Alzheimer's disease (AD) but reduced in other syndromes. Patients with bvFTD, SD, and AD showed altered coupling between pupillary and affective behavioral responses to emotionally salient sounds. DISCUSSION: Emotional sounds are a useful model system for analyzing how dementias affect the processing of salient environmental signals, with implications for defining pathophysiological mechanisms and novel biomarker development
Music Perception in Dementia.
Despite much recent interest in music and dementia, music perception has not been widely studied across dementia syndromes using an information processing approach. Here we addressed this issue in a cohort of 30 patients representing major dementia syndromes of typical Alzheimer's disease (AD, n = 16), logopenic aphasia (LPA, an Alzheimer variant syndrome; n = 5), and progressive nonfluent aphasia (PNFA; n = 9) in relation to 19 healthy age-matched individuals. We designed a novel neuropsychological battery to assess perception of musical patterns in the dimensions of pitch and temporal information (requiring detection of notes that deviated from the established pattern based on local or global sequence features) and musical scene analysis (requiring detection of a familiar tune within polyphonic harmony). Performance on these tests was referenced to generic auditory (timbral) deviance detection and recognition of familiar tunes and adjusted for general auditory working memory performance. Relative to healthy controls, patients with AD and LPA had group-level deficits of global pitch (melody contour) processing while patients with PNFA as a group had deficits of local (interval) as well as global pitch processing. There was substantial individual variation within syndromic groups. Taking working memory performance into account, no specific deficits of musical temporal processing, timbre processing, musical scene analysis, or tune recognition were identified. The findings suggest that particular aspects of music perception such as pitch pattern analysis may open a window on the processing of information streams in major dementia syndromes. The potential selectivity of musical deficits for particular dementia syndromes and particular dimensions of processing warrants further systematic investigation
Combining nano-physical and computational investigations to understand the nature of “aging” in dermal collagen
The extracellular matrix of the dermis is a complex, dynamic system with the various dermal components undergoing individual physiologic changes as we age. Age-related changes in the physical properties of collagen were investigated in particular by measuring the effect of aging, most likely due to the accumulation of advanced glycation end product (AGE) cross-links, on the nanomechanical properties of the collagen fibril using atomic force microscope nano-indentation. An age-related decrease in the Young’s modulus of the transverse fibril was observed (from 8.11 to 4.19 GPa in young to old volunteers, respectively, P<0.001). It is proposed that this is due to a change in the fibril density caused by age-related differences in water retention within the fibrils. The new collagen–water interaction mechanism was verified by electronic structure calculations, showing it to be energetically feasible
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