We analyze recently measured total reaction cross sections for [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Mg isotopes incident on 12 C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics (AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Mg are then deduced from the measured reaction cross sections by fine tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for [24][25][26][27][28][29][30][31][32][33][34][35][36] Mg, but still considerably underestimate them for 37,38 Mg. The large matter radii suggest that 37,38 Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number (N ) dependence of deformation parameter is predicted by AMD. Large deformation is seen from 31 Mg with N = 19 to a drip-line nucleus 40 Mg with N = 28, indicating that both the N = 20 and 28 magicities disappear. N dependence of neutron skin thickness is also predicted by AMD.

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Precise reaction cross sections (oR) for 24_38M g on C targets at energies around 240 M eV /nucleon have been measured at the Radioactive Isotope Beam Factory at RIKEN. The oR for 36-38 Mg have been measured for the first time. An enhancement o f oR compared to the systematics for spherical stable nuclei has been observed, especially in the neutron-rich region, which reflects the deformation of those isotopes. In the vicinity of the drip line the aR for 37Mg is especially large. It is shown by analysis using a recently developed theoretical method that this prominent enhancement of oR for 37Mg should come from the p-orbital halo formation breaking the N = 28 shell gap.Since the early years of the study of atomic nuclei, the nuclear shell model has been the basic framework for understanding nuclear structure. The high stability of nuclei with certain numbers of neutrons (or protons) observed in stable nuclei indicates the existence of the shells filled at certain so-called "magic numbers." Studies in the last few decades have revealed that those magic numbers are sometimes broken or changed in unstable nuclei [1], The breakdown of the N = 20 shell gap between the sd and f p shells has been extensively studied since the irregularities in binding energies and 2+ excitation energies were observed in neutron-rich nuclei around N = 20 [2-6]. The term "island of inversion" was applied to this region [6] and deformed nuclear structures related to the changing of shell structures have been reported in this region [7]. The vanishing of the N = 28 shell closure has been also extensively studied, starting from neutronrich S-Ar isotopes [8][9][10][11][12][13][14]. The development of deformation observed in those nuclei could be interpreted as degeneracy of the f p shell, which induces strong quadrupole deformation [9][10][11][13][14][15][16][17][18]. Such deformation has been reported also for Si isotopes [19,20], and studies have recently indicated that this * takechi @ np.gs .niigata-u. ac .jp PACS number(s): 21.10.Gv, 25.60.Dz phenomenon could be seen even in a very neutron-rich Mg region [21].The purpose of our present study is to elucidate the changes of nuclear structures, such as a development of deformation, a breakdown of the magic numbers and possible halo formation in Mg isotopes, from the stability line to the vicinity of the neutron drip line. For this purpose, precise measurements of reaction cross sections for 24_38Mg have been performed at the Radioactive Isotope Beam Factory (RIBF) at RIKEN. The reaction cross section aR or interaction cross section ay reflects the nuclear size, and has been a powerful probe in searching for halo formation since the first study by Tanihata et al. [22], Recently, measurements of o, for Ne isotopes performed at RIBF [23] have successfully revealed the halo structure of 3lNe in which the sd-pf shell inversion associated with nuclear deformation causes the formation of a halo [23][24][25]. Moreover, theoretical studies on those data have shown that a precise data set on crR is v...

Recently we have proposed a reliable method to describe the rotational band in a fully microscopic manner. The method has recourse to the configuration-mixing of several cranked mean-field wave functions after the angular-momentum-projection. By applying the method with the Gogny D1S force as an effective interaction, we investigate the moments of inertia of the ground state rotational bands in a number of selected nuclei in the rare earth region. As another application we try to describe, for the first time, the two-neutron aligned band in 164 Er, which crosses the ground state band and becomes the yrast states at higher spins. Fairly good overall agreements with the experimental data are achieved; for nuclei, where the pairing correlations are properly described, the agreements are excellent. This confirms that the previously proposed method is really useful for study of the nuclear rotational motion.

Nine patients with hepatocellular carcinoma originating in the caudate lobe who underwent hepatic resection were studied. The caudate lobe was divided into three parts, according to the criteria of Kumon, including the Spiegel lobe, the paracaval portion and the caudate process. The tumors were located in the Spiegel lobe in four, the paracaval portion in four and the caudate process in one. Surgical procedures consisted of right hepatic lobectomy in one, central bisegmentectomy in one and caudate lobectomy in seven.The mean surgical time was 379 * 129 min; the mean estimated blood loss was 2,994 * 2,303 ml. The abovementioned surgical risks were more clearly recognized in the paracaval portion than in the Spiegel lobe. In addition, most patients experienced significant postoperative complications. Six of eight patients with 6 mo or longer follow-up had recurrences, and two of six patients died. The characteristics of hepatocellular carcinoma in the caudate lobe were as follows: (a) a higher surgical risk, and more definite risk in the paracaval portion; and (b) a higher rate of early recurrence. A left lobectomy for the Spiegel lobe, a right or left trisegmentectomy for the paracaval portion and a right lobectomy for the caudate process would be ideal from the point of view of the portal supply of the caudate lobe. However, in cirrhotic patients either a caudate lobectomy or partial resection might be preferable because longer survival can be expected. (HEPATOLOGY 1994;19911-915.) The widespread use of ultrasonography, computed tomography (CT), nuclear magnetic resonance imaging and or-fetoprotein (AFP) estimation has increasingly allowed for the earlier detection of HCC (1-3). As a result, small tumors can now be detected that can then be evaluated for surgical resection. Moreover, recent advances in liver surgery have made hepatic resection much safer (4-7). However, even now, hepatic resection for HCCs in the hepatic hilus or near the inferior vena PATIENTS AND METHODSBetween April 1990 and December 1992, nine patients with HCC originating in the caudate lobe, who underwent hepatic resection, were studied. The patients were closely followed up after surgery at regular 1-mo intervals. Each follow-up visit included a physical examination, blood chemistry tests and the measurement of AFP levels. Ultrasonography and CT were performed at least at 3-mo intervals. when recurrence was suspeded, the patients were readmitted for angiographical evaluation. Final confirmation of the patients' status was carried out in July 1993.The caudate lobe was divided into three parts as described by Kumon (8), including (a) the Spiegel lobe, (b) the paracaval portion and (c) the caudate process. The Spiegel lobe is defined as the portion under the lesser omentum and the left-sided portion of the intrahepatic inferior vena cava (IVC), and the paracaval portion is defined as the front portion of intrahepatic IVC extending just right to the Spiegel lobe from the caudate process to the area between the roots of the right and midde ...