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The {beta}{sup +}/EC decay of mass-separated A=80 nuclei was studied by means of {beta}- and {gamma}-ray spectroscopy after the bombardment of a {sup 24}Mg target with {sup 58}Ni ions at 190 MeV. A new 1{sup {minus}} isomer at 228.5(1) keV has been identified in {sup 80}Y with a half-life of 4.7(3) s. This new isomer decays to the 4{sup {minus}} ground state with an 81(2){percent} branch and by {beta}{sup +}/EC transitions to levels in {sup 80}Sr with a 19(2){percent} branch. The half-life of the {sup 80}Y ground-state decay has been remeasured to be 30.1(5) s. A level scheme for the low-lying states in {sup 80}Y is presented. Hartree-Fock-Bogolyubov calculations show a large prolate deformation for these states, and two-quasiparticle + rotor model calculation results suggest that the low-lying states can be reproduced by inclusion of an effective proton-neutron residual interaction. The dominating Nilsson configurations for the 4{sup {minus}} ground state and the 1{sup {minus}} isomeric state have been found to originate from the parallel and antiparallel coupling of the proton [422]5/2{sup +} and the neutron [301]3/2{sup {minus}} orbitals. {copyright} {ital 1998} {ital The American Physical Society}

Over the past decade or so, well-understood procedures and methodologies have evolved within computer forensics digital evidence collection. Correspondingly, many organizations such as the HTCIA (High Technology Criminal Investigators Association) and IACIS (International Association of Computer Investigative Specialists) have emphasized disk imaging procedures which ensure reliability, completeness, accuracy, and verifiability of computer disk evidence. The rapidly increasing and changing volume of data within corporate network information systems and personal computers are driving the need to revisit current evidence collection methodologies. These methodologies must evolve to maintain the balance between electronic environmental pressures and legal standards. This paper posits that the current methodology which focuses on collecting entire bit-stream images of original evidence disk is increasing legal and financial risks. The first section frames the debate and change drivers for a Risk Sensitive approach to digital evidence collection, which is followed by the current methods of evidence collection along with a cost-benefit analysis. Then the methodology components of the Risk Sensitive approach to collection, and then concludes with a legal and resource risk assessment of this approach. Anticipated legal arguments are explored and countered, as well. The authors suggest an evolved evidence collection methodology which is more responsive to voluminous data cases while balancing the legal requirements for reliability, completeness, accuracy, and verifiability of evidence.

For many nuclei beyond the proton drip line in the Z > 72, N > 82 region, both proton and α emission are energetically allowed. In the case of some proton emitters, there are α-decay chains emanating from both parent and daughter nuclei. This means that if the mass excess of one member of an α-decay chain is known, then the mass excesses for all members of both chains can be obtained. In addition, proton separation energies may be derived for nuclei in the α-decay chain of the proton emitter. The method of time- and space-correlations also allows the identification of isomeric states in these nuclei. As an example, a large number of mass excesses and proton separation energies for ground and metastable states have been derived from Q α and Q p values obtained from the proton emitters 165,166,167Ir, 171Au, 177Tl and their daughters.

Ground and isomeric proton and alpha decay branches are reported for the new isotope ${}^{177}\mathrm{Tl},$ produced by bombarding a ${}^{102}\mathrm{Pd}$ target with a 370 MeV beam of ${}^{78}\mathrm{Kr}$ ions. The ground state is assigned as a $\ensuremath{\pi}{s}_{1/2}$ configuration and the high spin isomer is assigned as a $(\ensuremath{\pi}{h}_{11/2}{)}^{\ensuremath{-}1}$ configuration. The ground-state proton decay of ${}^{171}\mathrm{Au}$ has been identified for the first time, produced by bombarding a ${}^{96}\mathrm{Ru}$ target with ${}^{78}\mathrm{Kr}$ ions. The ${}^{171}\mathrm{Au}$ ground state is also assigned as a $\ensuremath{\pi}{s}_{1/2}$ configuration. Spectroscopic factors, masses, and proton separation energies are derived using these new proton decay measurements. New ground-state $\ensuremath{\alpha}$ decays for ${}^{169}\mathrm{Ir}$ and ${}^{173}\mathrm{Au}$ are also reported.

The {beta}{sup +}/EC decay of a mass-separated {sup 80}Y source has been studied by {beta}- and {gamma}-ray spectroscopy following the bombardment of a thin {sup 24}Mg target with {sup 58}Ni ions at 190 MeV. An extended decay scheme with 14 new states in {sup 80}Sr has been identified including the first observation of negative-parity states. The low-lying positive-parity states have been found to be clustered indicating a pattern of one-, two-, and possibly three-phonon multiplets characteristic of an anharmonic vibrator. Some states in {sup 80}Sr can also be grouped into a {gamma}-vibrational band. In general the low-lying states in light strontium isotopes show vibrationlike collectivity which evolves to rotational behavior with increasing spin and decreasing neutron number. The observed {sup 80}Ythinsp{beta}-decay fragmentation and log ft values have also been used to assign spin and parity of 4{sup {minus}} and 1{sup {minus}} to the parent ground state and the 228.5 keV isomeric state, respectively. {copyright} {ital 1999} {ital The American Physical Society}

In-beam \ensuremath{\gamma} rays have been observed in the neutron-deficient isotopes ${}^{170,171,172}\mathrm{Pt}$ using the recoil-decay tagging technique. The yrast transition sequence proposed for ${}^{172}\mathrm{Pt}$ indicates that the ${0}^{+}$ bandhead of the deformed intruder band is situated about 900 keV above the weakly deformed ground state, i.e., its excitation energy has risen by about 300 keV compared to ${}^{174}\mathrm{Pt}.$ The measured energy of the ${2}^{+}\ensuremath{\rightarrow}{0}^{+}$ transition in ${}^{170}\mathrm{Pt}$ supports an even larger increase in the excitation energy of the intruder configuration with the departure from the middle of the 82--126 major neutron shell. Furthermore, a band with transition energies almost identical to those found in ${}^{172}\mathrm{Pt}$ has been assigned to ${}^{171}\mathrm{Pt}$ and was interpreted as corresponding to a rotationally aligned ${i}_{13/2}$ neutron orbital coupled to the core excitations.

With the use of a fragment mass analyzer, the $\ensuremath{\alpha}$ decay of ${}^{180}\mathrm{Tl}$ was identified in ${}^{92}\mathrm{Mo}$ bombardments of ${}^{90}\mathrm{Zr}.$ At least three \ensuremath{\alpha} transitions were observed but on the basis of the data obtained it was not possible to conclude if they originate from one or more levels in ${}^{180}\mathrm{Tl}.$ In the same irradiations a new \ensuremath{\alpha} group was also identified in ${}^{179}{\mathrm{Tl}}^{m}$ decay. Based on energy and half-life systematics, it appears that ${}^{179}{\mathrm{Tl}}^{m},$ in contrast to the isomers in heavier odd-A Tl nuclei, is not the ${h}_{9/2}$ intruder level but rather the ${h}_{11/2}$ proton state.

In-beam γ-ray transitions in 181Hg, the lightest odd-A Hg isotope known thus far, have been identified from fragment mass-γ and γ-γ coincidence measurements. Five prolate deformed rotational bands were placed in the level scheme. A decoupled band built on the strongly prolate deformed 1 2 − [521] ground state was observed up to 29 2 − . A 5 2 − [512] configuration is suggested for a pair of strongly coupled bands displaying no signature splitting. The other two bands are also signature partner bands. They are populated with the largest intensity and exhibit splitting. They have been associated with the mixed neutron i 13 2 orbitals and are proposed to decay to an i 13 2 isomeric state associated with an oblate state.

Excited states have been observed for the first time in the neutron-deficient {sup 176,178}Hg nuclei using the recoil-decay tagging (RDT) technique in which prompt {gamma} rays are associated with a particular isotope through a correlation with the characteristic ground state {alpha} decay. Below N=102, the excitation energy of a rotational band built on a prolate shape ({beta}{sub 2}{approximately}0.25) increases with decreasing mass to the point where there is no longer any evidence for its presence at low spin in {sup 176}Hg. The data are in qualitative agreement with recent mean field calculations. {copyright} {ital 1997} {ital The American Physical Society}

Gamma rays from the decay of states in the proton unstable nucleus {sup 147}Tm were observed for the first time following the {sup 92}Mo({sup 58}Ni,p2n){sup 147}Tm reaction at 260 MeV. Prompt {gamma} rays were detected with an array of Compton-suppressed Ge detectors, placed in front of the fragment mass analyzer at the ATLAS accelerator, and were assigned to individual reaction channels on an event-by-event basis using the recoil-decay tagging method. Gamma-ray transitions were associated with both the proton decay of the {pi}h{sub 11/2} ground state and the {pi}d{sub 3/2} isomeric state in {sup 147}Tm, even though the cross sections for populating these states were only {approx} 16 {mu}b and 2 {mu}b, respectively. The level scheme which was constructed for {sup 147}Tm is discussed and compared with the level structures for lighter N=78 isotones. {copyright} {ital 1997} {ital The American Physical Society}

The $\ensuremath{\alpha}$-decay properties of ${}^{190}$Po were investigated through the use of a fragment mass analyzer in conjunction with a double-sided Si strip detector. The isotope was produced via the ${}^{96}\mathrm{Mo}{(}^{96}\mathrm{Mo},2n)$ reaction, and its $\ensuremath{\alpha}$-decay energy and ${T}_{1/2}$ were measured as 7529(10) keV and ${2.4}_{\ensuremath{-}0.3}^{+0.4}$ ms, respectively. The resulting reduced width is nearly identical to that of the ${}^{192,194}\mathrm{Po}$ isotopes. This is believed to result from significant mixing between the ground state $\ensuremath{\pi}(2p)$ and the low-lying ${0}^{+}\ensuremath{\pi}(4p\ensuremath{-}2h)$ intruder state in the Po parent. The result provides further evidence for shape coexistence in the light Po isotopes. In addition, ${}^{191}\mathrm{Po}$ was unambiguously identified, and the ${}^{186}\mathrm{Pb}$ $\ensuremath{\alpha}$-decay branch was determined experimentally for the first time.

The new proton radioactivities ${}^{165,166,167}\mathrm{Ir}$ and ${}^{171}\mathrm{Au}$ have been observed. The Ir isotopes were produced via the ${}^{92}\mathrm{Mo}{(}^{78}\mathrm{Kr}{,pxn)}^{165,166,167}\mathrm{Ir}$ reactions at 357 and 384 MeV. ${}^{171}\mathrm{Au}$ was produced via the ${}^{96}\mathrm{Ru}{(}^{78}\mathrm{Kr}{,p2n)}^{171}\mathrm{Au}$ reaction at 389 MeV. The proton emitters were each identified by position, time, and energy correlations between the implantation of a residual nucleus into a double-sided silicon strip detector, the observation of a decay proton, and the subsequent observation of a decay alpha particle from the daughter nucleus (${}^{164,165,166}$Os and ${}^{170}\mathrm{Pt},$ respectively). Both ${}^{166}\mathrm{Ir}$ and ${}^{167}\mathrm{Ir}$ have proton-emitting ground and isomeric states, which also decay by alpha emission. The proton-decay rates have been reproduced by calculations using the WKB barrier penetration approximation and a low-seniority shell-model calculation of the spectroscopic factors. The alpha decays of the four nuclei are followed by chains of alpha decays, allowing the determination of single-particle orbital orderings. Mass information has also been obtained from the alpha-decay chains because a connection to a known mass can be obtained for one of the nuclei. Ground-state mass excesses are reported for ${}^{151}\mathrm{Tm},$ ${}^{154}\mathrm{Yb},$ ${}^{155}\mathrm{Lu},$ ${}^{158}\mathrm{Hf},$ ${}^{159}\mathrm{Ta},$ ${}^{162}\mathrm{W},$ ${}^{163}\mathrm{Re},$ ${}^{166}\mathrm{Os},$ ${}^{167}\mathrm{Ir},$ and ${}^{170}\mathrm{Pt}.$ The mass excess for ${}^{171m}\mathrm{Au}$ is also given. Proton separation energies are also deduced for the odd-$Z$ alpha daughter nuclei of the Ir proton emitters.

Proton radioactivities from {sup 157}Ta and {sup 161}Re are reported. Fusion-evaporation residues from the reaction of 270 MeV {sup 58}Ni ions on {sup 102}Pd and {sup 106}Cd targets were separated according to M/Q and implanted into a double-sided silicon strip detector. One line from {sup 157}Ta was observed with a proton energy of 927(7) keV [t{sub 1/2}=10.1(4) ms, b{sub p}=3.4(12){percent}] from the {pi}s{sub 1/2} ground state. A new alpha decay transition with energy 6117(4) keV was also observed from this state. Two proton lines from {sup 161}Re were observed with energies 1192(6) keV [t{sub 1/2}=0.37(4) ms, b{sub p}=100(7){percent}] and 1315(7) keV [t{sub 1/2}=16(1) ms, b{sub p}=4.8(6){percent}] from the {pi}s{sub 1/2} and {pi}h{sub 11/2} states, respectively. {copyright} {ital 1997} {ital The American Physical Society}

Excitations in {sup 192}Po have been studied via in-beam {gamma}-ray spectroscopy following the {sup 164}Er + 164 MeV {sup 32}S reaction. The experiment was performed at the ATLAS facility using ten Compton-suppressed Ge detectors and the Fragment Mass Analyzer. The {alpha} decay of {sup 192}Po has been used to identify prompt {gamma}-ray transitions by means of the recoil decay tagging technique. The first three excited states of {sup 192}Po were established. The particle-core model has been successfully used to model these excitations and the quasiparticle random phase approximation has been applied to extract microscopic wave functions of the 2{sub 1}{sup +} states. {copyright} {ital 1997} {ital The American Physical Society}

In a series of $^{78}\mathrm{Kr}$ bombardments of $^{92}\mathrm{Mo}$ the new isotopes $^{166}\mathrm{Pt}$ and $^{167}\mathrm{Pt}$ were identified via their $\ensuremath{\alpha}$-decay properties. The $\ensuremath{\alpha}$-decay energies and half-lives of these two nuclides are as follows. (1) $^{166}\mathrm{Pt}$, ${E}_{\ensuremath{\alpha}}=7110(15)$ keV, ${T}_{\frac{1}{2}}=0.3(1)$ ms, and (2) $^{167}\mathrm{Pt}$, ${E}_{\ensuremath{\alpha}}=6988(10)$ keV, ${T}_{\frac{1}{2}}=0.7(2)$ ms. Also, the half-life of $^{168}\mathrm{Pt}$, which was previously unknown, was determined to be 2.0(4) ms. In a separate but concurrent experiment involving $^{78}\mathrm{Kr}$ + $^{96}\mathrm{Ru}$ reactions, $^{170}\mathrm{Pt}$ was made and a half-life of 14.7(5) ms was measured for it; the one published value is ${6}_{\ensuremath{-}2}^{+5}$ ms. Results for $^{162\ensuremath{-}164}\mathrm{Os}$ contained in the same data sets were also analyzed and by using mother-daughter correlations, the $\ensuremath{\alpha}$ branches of $^{162,163,164}\mathrm{Os}$ were established to be near 100%.

The new proton radioactivity ${}^{185m}\mathrm{Bi}$ has been observed, produced via the ${}^{95}\mathrm{Mo}{(}^{92}\mathrm{Mo},pn{)}^{185}\mathrm{Bi}$ reaction. Its decay proceeds from the low-lying ${\frac{1}{2}}^{+}$ intruder state in ${}^{185}\mathrm{Bi}$ to the ${}^{184}\mathrm{Pb}$ ground state with the emission of a proton of energy $1.585\ifmmode\pm\else\textpm\fi{}0.009\mathrm{MeV}$ and a half-life of $44\ifmmode\pm\else\textpm\fi{}16\ensuremath{\mu}\mathrm{s}$. This marks the first observation of proton radioactivity above the $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}82$ closed shell, and it has been used to obtain the admixture of a ${0}^{+}$ intruder state in ${}^{184}\mathrm{Pb}$ into the ${}^{184}\mathrm{Pb}$ ground-state wave function.

A new in-beam study in $^{183}\mathrm{Hg}$ levels has been carried out by using the $^{155}\mathrm{Gd}$${(}^{32}$S,4n) reaction at a beam energy of 160 MeV. A new pair of signature-partner bands, with large signature splitting, has been established in $^{183}\mathrm{Hg}$. The band head of these signature-partner bands is assigned to be the ground state of $^{183}\mathrm{Hg}$ with a configuration of 1/${2}^{\mathrm{\ensuremath{-}}}$[521]. The measured ratios of directional correlations (DCO ratios) revealed decay patterns for the proposed 9/${2}^{+}$[624] bands in $^{183}\mathrm{Hg}$ different from those of $^{185}\mathrm{Hg}$.

Excited structures in the $Z=80,{ }^{178}\mathrm{Hg} (N=98),$ and ${}^{180}\mathrm{Hg} (N=100)$ isotopes have been investigated with the Gammasphere spectrometer in conjunction with the recoil-decay tagging technique. The present data extend the previously known ground-state bands to higher spin and excitation energy. Negative parity bands with a complex decay towards the low spin states arising from both the prolate-deformed and the nearly spherical coexisting minima have been observed for the first time in both nuclei. It is shown that these sequences have characteristics in common with negative-parity bands in the heavier even-even Hg isotopes as well as in the Os and Pt isotones. These structures are interpreted as being associated at low spin with an octupole vibration which is crossed at moderate frequency by a shape driving, two-quasiproton excitation.

Collective structures in ${}^{178}\mathrm{Pt}$ have been investigated with $\ensuremath{\gamma}$-ray spectroscopic techniques following mass selection. The present data expand considerably the level scheme of this nucleus. A new collective structure has been identified and the known bands have been extended to higher spins. Firm spin and parity assignments have been made to many levels. Of particular interest are the negative parity bands which are interpreted in terms of structures associated with octupole vibrations crossed at moderate spin by two-quasiparticle excitations. The systematics of the $\ensuremath{\alpha}$-decay reduced widths in Pt nuclei has also been investigated. The differences of a factor of about 2 between the widths for the odd- and the even-$A$ isotopes is attributed to changes in neutron pairing associated with the blocking effect. The trend is reproduced in calculations based on the Lipkin-Nogami pairing model.

Using the GAMMASPHERE array in conjunction with the Fragment Mass Analyzer, the level structure of the near drip-line nucleus {sup 178}Hg has been considerably expanded with the recoil-decay tagging technique. Of particular interest is a new rotational band which exhibits a complex decay towards the low spin states arising from both the prolate-deformed and the nearly spherical coexisting minima. It is proposed that this band is associated at low spin with an octupole vibration which is crossed at moderate frequency by a shape driving, two quasiproton excitation. (c) 1999 The American Physical Society.

The $\ensuremath{\alpha}$ decays of the two neutron-deficient nuclei ${}^{172}\mathrm{Hg}$ and ${}^{173}\mathrm{Hg}$ were observed for the first time using the ${}^{78}\mathrm{Kr}{(}^{96}\mathrm{Ru},2n)$ and ${}^{80}\mathrm{Kr}{(}^{96}\mathrm{Ru},3n)$ reactions, respectively. The reaction products were dispersed according to their mass-to-charge state ratios in the Argonne Fragment Mass Analyzer and implanted in a double-sided silicon strip detector, where their subsequent decays were studied using spatial and time correlations between implants and decays. A half-life of ${250(}_{\ensuremath{-}90}^{+350}) \ensuremath{\mu}\mathrm{s}$ and an energy of 7350(12) keV were deduced for the $\ensuremath{\alpha}$ decay of ${}^{172}\mathrm{Hg}$. In ${}^{173}\mathrm{Hg}$ the half-life was measured to be ${0.93(}_{\ensuremath{-}0.26}^{+0.57}) \mathrm{ms}$ and the corresponding energy is 7211(11) keV. In addition, the half-life and energy of the $\ensuremath{\alpha}$ decay of ${}^{174}\mathrm{Hg}$ were measured more precisely. The reduced widths deduced for these Hg isotopes indicate that the observed decays correspond to unhindered $\ensuremath{\Delta}l=0$ transitions. The $\ensuremath{\alpha}$-decay Q values are compared with the values calculated using mass tables by M\"oller and Nix, and by Liran and Zeldes. The latter mass tables show better agreement with the data.

The proton-rich isotopes ${}^{180}\mathrm{Pb},$ ${}^{182}\mathrm{Pb}$, and ${}^{184}\mathrm{Pb}$ were produced in ${}^{92}\mathrm{Mo}$ bombardments of ${}^{90}\mathrm{Zr},$ ${}^{92}\mathrm{Zr}$, and ${}^{94}\mathrm{Zr}$, respectively, and their $\ensuremath{\alpha}$-decay properties were investigated with the use of a fragment mass analyzer and a double-sided Si strip detector. These data yielded unambiguous identifications of ${}^{180}\mathrm{Pb}$ and ${}^{182}\mathrm{Pb}$ and half-lives for all three Pb nuclei that are more precise than previously available values. An examination of $\ensuremath{\alpha}$ reduced widths in the Pb mass region leads to the conclusion that the $Z=82$ shell gap is greatly reduced for neutron numbers midway between 82 and 126. Available mass data, manifested in $\ensuremath{\Delta}{Q}_{\ensuremath{\alpha}}$ values and two-proton separation energies of even-even nuclei with the same neutron numbers, support this conclusion.

Fine structure in the α decay of 192Po has been studied in the reaction of 36Ar on 160Dy at 176 MeV. Evaporation residues were selected in-flight using the Argonne Mass Analyzer and implanted into a double sided silicon strip detector. The correlation technique between implants and subsequent decays was used to observe fine structure in the α decay of 192Po leading to the identification of an excited 0+ state in 188Pb at 571(31) keV. The half-life of 192Po has been determined to be 33.2(14) ms. The observation of a low-lying 0+ state is discussed in terms of proton particle-hole pair excitations across the Z=82 shell gap. The small hindrance factor to the excited 0+ state relative to the ground state supports the picture of shape coexistence in light even-even Po isotopes.

Intruder state excitation energies in odd-mass nuclei just outside a closed proton shell plotted versus neutron number generally exhibit parabola-shaped curves with minima near neutron mid-shells. The Bi isotopes, however, do not seem to follow this trend. Recent experiments performed at Argonne National Laboratory have identified the previously unobserved {sup 187}Bi ground state (h{sub 9/2}) to {sup 183}TI ground state s{sub 1/2} {alpha} transition. Its energy when combined with those of two earlier known transitions, namely {sup 187}Bi (h{sub 9/2}) {yields} {sup 183m}Tl (h{sub 9/2}) and {sup 187m}Bi (s{sub 1/2}) {yields} {sup 183}Tl(s{sub 1/2}), establishes the excitation energies of the {sup 183m}Tl and {sup 187m}Bi to be 620(20) keV and 110(20) keV, respectively. This value for {sup 187m}Bi is 80 keV lower than the excitation energy of the same intruder level in {sup 189}Bi. Implications of this result with respect to intruder-state systematics are discussed.

In a series of experiments at the Argonne ATLAS Accelerator Facility, several α emitters near the proton drip line were produced with fusion evaporation reactions, separated from the beam and dispersed in M/Q with a recoil mass spectrometer, and implanted and studied in a double-sided silicon strip detector. In 78Kr bombardments of 92Mo and 96Ru, the new isotopes 166Pt and 167Pt were identified via their α-decay properties and more accurate half-lives were measured for 168Pt and 170Pt. The light isotopes of lead, 180Pb, 182Pb, and 184Pb were produced in Mo bombardments of Zr target nuclei. The α-decay energies and half-lives of the new isotopes are as follows: 1) 166Pt, Eα=7110(15) keV, T1/2=0.3(1) ms; and 2) 167Pt, Eα=6988(10) keV, T1/2=0.7(2) ms. Also, the half-life of 168Pt, which was previously unknown, was determined to be 2.0(4) ms and that of 170Pt was observed to be 14.7(5) ms. The tentative α-decay energies and half-lives of the even Pb isotopes are: 1) 184Pb, Eα=6625(10) keV, T1/2=500(25) ms; 2)...

This article is an epidemiological analysis of Baltimore homicides between 1986 and 1990. The main findings were that young African-American males between 15 and 34 years of age are at greatest risk of homicide victimization. Homicidal events primarily occurred with handguns, in drug-related circumstances, between acquaintances, and in the western police district area. Questions are raised concerning the expansion of the public health professional's role and the use of epidemiologic data for injury prevention programs. This article is the result of a grant from the Centers for Disease Control and Prevention, Division of Injury Control, to the state of Maryland, Department of Health and Mental Hygiene, and the Baltimore City Health Department.

Continuous pulse oximetry monitoring was used to determine the incidence of hypoxaemia (arterial oxygen saturation less than or equal to 90%) occurring in the first hour of postoperative recovery. Of 107 patients studied, hypoxaemia was recorded in 80%. Twenty-eight (26%) of these patients had saturations below 80%. The average frequency (i.e., the number of desaturations per patient) and the total duration of these desaturations was 7.7 desaturations and 182 seconds respectively. Intermittent measurements taken preoperatively and at 5 and 30 minutes postoperatively revealed hypoxaemia in 2%, 4% and 6% of patients respectively. In 39 patients who received oxygen therapy throughout the monitoring period, 64% experienced hypoxaemia within the first 15 minutes of recovery as opposed to only 18% in the final 15 minutes monitoring period. Of the factors assessed, only patients with a body mass index greater than 25 had an increased risk of hypoxaemia (P less than 0.01). Four patients required active intervention and ventilatory assistance. We conclude that postoperative hypoxaemia is a particularly common occurrence even in patients otherwise considered healthy. Hence, pulse oximetry should be employed routinely during recovery. Where possible, monitoring should be performed continuously for at least 45 minutes.

The α decay of 186Bi was investigated via the 97Mo(92Mo, p2n) reaction and the use of a fragment mass analyzer with a double-sided Si strip detector. In contrast to an earlier work wherein only one α transition was reported, we observed two transitions arising from two isomers in 186Bi with energies and half-lives of: 7158(20) keV, T1/2 = 15.0(17) ms; and 7261(20) keV, T1/2 = 9.8(13) ms.

Prompt, in-beam γ rays in coincidence with evaporation residues were measured in the 164,166Er + 164 MeV 32S reactions. A level scheme built on the 13/2+ isomer has been deduced from four transitions assigned to 191Pb. The states in 191Pb are interpreted in terms of a weak coupling of the odd i13/2 neutron-hole to the spherical states in the even-mass 192Pb core.