Population of 13Be in a Nucleon Exchange Reaction

The neutron-unbound nucleus 13Be was populated with a nucleon-exchange reaction from a 71 MeV/u secondary 13B beam. The decay energy spectrum was reconstructed using invariant mass spectroscopy based on 12Be fragments in coincidence with neutrons. The data could be described with an s-wave resonance at E = 0.73(9) MeV with a width of Gamma = 1.98(34) MeV and a d-wave resonance at E = 2.56(13) MeV with a width of Gamma = 2.29(73) MeV. The observed spectral shape is consistent with previous one-proton removal reaction measurements from 14B.Comment: Published in Phys. Rev.

Molecular Structures in T=1 states of 10B

Multi-center (molecular) structures can play an important role in light nuclei. The highly deformed rotational band in 10Be with band head at 6.179 MeV has been observed recently and suggested to have an exotic alpha:2n:alpha configuration. A search for states with alpha:pn:alpha two-center molecular configurations in 10B that are analogous to the states with alpha:2n:alpha structure in 10Be has been performed. The T=1 isobaric analog states in 10B were studied in the excitation energy range of E=8.7-12.1 MeV using the reaction 1H(9Be,alpha)6Li*(T=1, 0+, 3.56 MeV). An R-matrix analysis was used to extract parameters for the states observed in the (p,alpha) excitation function. Five T=1 states in 10B have been identified. The known 2+ and 3- states at 8.9 MeV have been observed and their partial widths have been measured. The spin-parities and partial widths for three higher lying states were determined. Our data support theoretical predictions that the 2+ state at 8.9 MeV (isobaric analog of the 7.54 MeV state in 10Be) is a highly clustered state and can be identified as a member of the alpha:np:alpha rotational band. The next member of this band, the 4+ state, has not been found. A very broad 0+ state at 11 MeV that corresponds to pure alpha+6Li(0+,T=1) configuration is suggested and it might be related to similar structures found in 12C, 18O and 20Ne.Comment: 10 pages, 10 figures, accepted in Physical Review

An Analysis of Functional Status in Multiple Sclerosis Patients after Progressive Non-Aerobic High-Intensity Maximal Effort Exercise (MEE)

Background: Multiple Sclerosis (MS) is a disease with a wide-ranging impact on functional status. MS patient function has been assessed using Multiple Sclerosis Functional Composite Score (MSFCS). The MSFCS includes the standardized scores (Z-score) of three functional tests: the Paced Auditory Serial Addition Test (PASAT-3”) for cognitive function, 9-Hole Peg Test (9-HPT) for upper extremity function, and timed 25-foot walk (25-TW) for lower extremity function. One of the most common symptoms experienced by MS patients is severe fatigue, often brought on suddenly by aerobic exercise. Non-aerobic maximal effort exercise (MEE) is thought to increase strength without increasing fatigue. The IsoPUMP® (Neuromuscular Engineering; Nashville, TN) is a stationary exercise device designed for patient use to safely perform MEE leg presses and whole body lunges using isometric and eccentric exercises. The progressive functional changes of the MS patients were tracked using the MSFCs at specific intervals during the study

The Effect of Progressive Non-Aerobic High-Intensity Maximal Effort Exercise (MEE) on the Health-Related Quality of Life in Patients with Multiple Sclerosis

Background: Studies indicate that Multiple Sclerosis (MS) patients are less satisfied with the quality of their lives than healthy individuals in similar circumstances. Common symptoms experienced include fatigue, cognitive dysfunction, pain, spasticity, depression, bladder/bowel dysfunction and sexual dysfunction. Several pharmacological and non-pharmacological methods have been employed for such symptoms to try to increase quality of life and reduce the mortality rate. Non-pharmacological methods recommended for MS patients include lifestyle modifications, exercise programs and physical therapy. MS patients easily fatigue during aerobic exercise but a non-aerobic progressive maximal effort exercise (MEE) protocol consisting of a few short, duration isometric and eccentric leg press and whole body lunges was previously seen to increase strength without increasing fatigue. The IsoPUMP® (Neuromuscular Engineering, Nashville TN) exercise system permitted safe conduct and measurement of muscle strength and duration during each exercise repetition

Effects of Non-Aerobic Maximal Effort Exercise on Fatigue in Deconditioned Men and Women with Multiple Sclerosis

Multiple Sclerosis (MS) is a neurodegenerative disease of unknown etiology affecting women more frequently than men. Mental and physical fatigue complaints are often the most disabling symptoms for an MS patient. Both are multifactorial, potentially exacerbated by aerobic exercise, may prevent sustained physical functioning, and significantly interfere with activities of daily living1. A multi-center study was designed to investigate the effects of non-aerobic maximal effort exercise (MEE) for deconditioned persons with MS, with the expectation of minimizing fatigue. The IsoPUMP (Neuromuscular Engineering; Nashville, TN), is a specialized exercise and strength-sensing machine, designed to allow individuals to safely perform and record their non-aerobic MEE sessions. The Modified Fatigue Impact Scale (MFIS) and Multiple Sclerosis Functional Composite (MSFC) are common, accepted methods used to measure fatigue and function. The MFIS is a 21-item questionnaire which assesses the subjects’ perception of physical, cognitive, and psychosocial aspects of fatigue over a four-week period2. Each of the 21 items are scored on a scale from 0 (never) to 4 (almost always), and the total MFIS score is calculated by summing the circled number for each item. Total scores can range from 0 to 84; higher scores indicating a greater impact of fatigue on the person. The MFIS has three distinct subscales: (1) physical, (2) cognitive, and (3) psychosocial. These subscales can be scored independently by summing the questions that pertain to each subscale2. The MFIS physical subscale score can range from 0 – 36 and the MFIS cognitive subscale score can range from 0 – 40. The MSFC combines clinical measures used to assess lower limb function (Timed 25-Foot Walk [25-FW]), upper limb function (9-Hole Peg Test [9-HPT]), and cognition (Paced Auditory Serial Addition Test [PASAT-3”])3. The 25-FW is a quantitative measure of lower extremity function. The 9-HPT is a quantitative measure of arm and hand function where a subject inserts and then removes 9 pegs from a board, using one hand at a time. The time is recorded for each hand with the dominant hand trial first and the non-dominant hand trial second. The final score is recorded as the mean time for both hands. The PASAT-3” is a measure of cognitive function, specifically assessing auditory information processing speed, short-term memory, flexibility, and calculation ability. Cognitive dysfunction affects half of all MS patients; slowing ability to reason, concentrate, and recall5. In this test subjects listen to a series of 61 spoken numbers separated by 3 seconds and must add each number to the prior number. Their final PASAT-3” score is the number of correct additions in the series, with 60 reflecting a perfect score. The MSFC is then evaluated by creating Z-scores for each component, which compare each outcome with the average outcome of the study population. The three Z-scores are then averaged to create an overall composite score (the MSFC score) which represents change over time for that population of MS subjects3

Measurement of sub threshold resonance contributions to fusion reactions: the case of the 13C(α, n)16O astrophysical neutron source

The 13C(α, n)16O reaction is the neutron source for the main component of the s-process. It is is active inside the helium-burning shell of asymptotic giant branch stars, at temperatures ≲ 108 K. In this temperature region, corresponding to an energy interval of 140 − 230 keV, the 13C(α, n)16O cross section is dominated by the −3 keV sub-threshold resonance due to the 6.356 MeV level in 17O. Direct measurements could not establish its contribution owing to the Coulomb barrier between interacting nuclei, strongly reducing the cross section at astrophysical energies. Similarly, indirect measurements and extrapolations yielded inconsistent results, calling for further investigations. The Trojan Horse Method was applied to the 13C(6Li, n16O)d quasi-free reaction to access the low as well as the negative energy region of the 13C(α, n)16O reaction. By using the generalized R-matrix approach, the asymptotic normalization coefficient (C̃17O(1/2+)α13C)2 of the 6.356 MeV level was deduced. For the first time, the Trojan Horse Method and the asymptotic normalization coefficient were used in synergy. Our indirect approach lead to (C̃17O(1/2+)α13C)2 = 7.7−1.5+1.6 fm−1, slightly larger than the values in the literature, determining a 13C(α, n)16O reaction rate slightly larger than the one in the literature at temperatures lower than 108 K, with enhanced accuracy

Clustering in A=10 nuclei

We discuss the identification and properties of the states that belong to the highly clustered rotational band in A=10 nuclei, 10Be, 10B(T=1) and 10C. The band is of interest because it may correspond to an exotic α:nn:α configuration