Erratum: Measurement of d+

This corrects the article DOI: 10.1103/PhysRevLett.122.182701.

Measurement of d+

The cross sections of nuclear reactions between the radioisotope ^{7}Be and deuterium, a possible mechanism of reducing the production of mass-7 nuclides in big-bang nucleosynthesis, were measured at center-of-mass energies between 0.2 and 1.5 MeV. The measured cross sections are dominated by the (d,α) reaction channel, towards which prior experiments were mostly insensitive. A new resonance at 0.36(5) MeV with a strength of ωγ=1.7(5) keV was observed inside the relevant Gamow window. Calculations of nucleosynthesis outcomes based on the experimental cross section show that the resonance reduces the predicted abundance of primordial ^{7}Li, but not sufficiently to solve the primordial lithium problem.

Experimental Investigation of the

The ^{19}Ne(p,γ)^{20}Na reaction is the second step of a reaction chain which breaks out from the hot CNO cycle, following the ^{15}O(α,γ)^{19}Ne reaction at the onset of x-ray burst events. We investigate the spectrum of the lowest proton-unbound states in ^{20}Na in an effort to resolve contradictions in spin-parity assignments and extract reliable information about the thermal reaction rate. The proton-transfer reaction ^{19}Ne(d,n)^{20}Na is measured with a beam of the radioactive isotope ^{19}Ne at an energy around the Coulomb barrier and in inverse kinematics. We observe three proton resonances with the ^{19}Ne ground state, at 0.44, 0.66, and 0.82 MeV c.m. energies, which are assigned 3^{+}, 1^{+}, and (0^{+}), respectively. In addition, we identify two resonances with the first excited state in ^{19}Ne, one at 0.20 MeV and one, tentatively, at 0.54 MeV. These observations allow us for the first time to experimentally quantify the astrophysical reaction rate on an excited nuclear state. Our experiment shows an efficient path for thermal proton capture in ^{19}Ne(p,γ)^{20}Na, which proceeds through ground state and excited-state capture in almost equal parts and eliminates the possibility for this reaction to create a bottleneck in the breakout from the hot CNO cycle.

Role of the premotor cortex in recovery from middle cerebral artery infarction.

OBJECTIVE: To study the mechanisms underlying recovery from middle cerebral artery infarction in 7 patients with an average age of 53 years who showed marked recovery of hand function after acute severe hemiparesis caused by their first-ever stroke. INTERVENTIONS: Assessment of motor functions, transcranial magnetic stimulation, somatosensory evoked potentials, magnetic resonance imaging, and positron emission tomographic measurements of regional cerebral blood flow during finger movement activity. RESULTS: The infarctions involved the cerebral convexity along the central sulcus from the Sylvian fissure up to the hand area but spared the caudate nucleus, thalamus, middle and posterior portions of the internal capsule, and the dorsal part of the precentral gyrus in each patient. After recovery (and increase in motor function score of 57%, P<.001), the motor evoked potentials in the hand and leg muscles contralateral to the infarctions were normal, whereas the somatosensory evoked potentials from the contralateral median nerve were reduced. During fractionated finger movements of the recovered hand, regional cerebral blood flow increases occurred bilaterally in the dorsolateral and medial premotor areas but not in the sensorimotor cortex of either hemisphere. CONCLUSIONS: Motor recovery after cortical infarction in the middle cerebral artery territory appears to rely on activation of premotor cortical areas of both cerebral hemispheres. Thereby, short-term output from motor cortex is likely to be initiated.