Showing papers by "Williams College published in 1996"
TL;DR: It is proved that an EPP involving one-way classical communication and acting on mixed state M (obtained by sharing halves of Einstein-Podolsky-Rosen pairs through a channel) yields a QECC on \ensuremath{\chi} with rate Q=D, and vice versa, and it is proved Q is not increased by adding one- way classical communication.
Abstract: Entanglement purification protocols (EPPs) and quantum error-correcting codes (QECCs) provide two ways of protecting quantum states from interaction with the environment. In an EPP, perfectly entangled pure states are extracted, with some yield D, from a mixed state M shared by two parties; with a QECC, an arbitrary quantum state |\ensuremath{\xi}〉 can be transmitted at some rate Q through a noisy channel \ensuremath{\chi} without degradation. We prove that an EPP involving one-way classical communication and acting on mixed state M^(\ensuremath{\chi}) (obtained by sharing halves of Einstein-Podolsky-Rosen pairs through a channel \ensuremath{\chi}) yields a QECC on \ensuremath{\chi} with rate Q=D, and vice versa. We compare the amount of entanglement E(M) required to prepare a mixed state M by local actions with the amounts ${\mathit{D}}_{1}$(M) and ${\mathit{D}}_{2}$(M) that can be locally distilled from it by EPPs using one- and two-way classical communication, respectively, and give an exact expression for E(M) when M is Bell diagonal. While EPPs require classical communication, QECCs do not, and we prove Q is not increased by adding one-way classical communication. However, both D and Q can be increased by adding two-way communication. We show that certain noisy quantum channels, for example a 50% depolarizing channel, can be used for reliable transmission of quantum states if two-way communication is available, but cannot be used if only one-way communication is available. We exhibit a family of codes based on universal hashing able to achieve an asymptotic Q (or D) of 1-S for simple noise models, where S is the error entropy. We also obtain a specific, simple 5-bit single-error-correcting quantum block code. We prove that iff a QECC results in high fidelity for the case of no error then the QECC can be recast into a form where the encoder is the matrix inverse of the decoder. \textcopyright{} 1996 The American Physical Society.
4,563 citations
TL;DR: Upper and lower bounds on the yield of pure singlets ($\ket{\Psi^-}$) distillable from mixed states $M$ are given, showing $D(M)>0$ if $\bra{Psi-}M\ket-}>\half$.
Abstract: Two separated observers, by applying local operations to a supply of not-too-impure entangled states (e.g., singlets shared through a noisy channel), can prepare a smaller number of entangled pairs of arbitrarily high purity (e.g., near-perfect singlets). These can then be used to faithfully teleport unknown quantum states from one observer to the other, thereby achieving faithful transmission of quantum information through a noisy channel. We give upper and lower bounds on the yield $D\left(M\right)$ of pure singlets $(|{\ensuremath{\Psi}}^{\ensuremath{-}}〉)$ distillable from mixed states $M$, showing $D\left(M\right)g0$ if $〈{\ensuremath{\Psi}}^{\ensuremath{-}}|M|{\ensuremath{\Psi}}^{\ensuremath{-}}〉g\frac{1}{2}$.
2,358 citations
TL;DR: The data indicated that the discounting rate is a decreasing function of the size of the delayed reward (p < .0001), whether hyperbolic or exponential discounting functions are assumed.
Abstract: The independence of delay-discounting rate and monetary reward size was tested by offering subjects (N = 621) a series of choices between immediate rewards and larger, delayed rewards. In contrast to previous studies, in which hypothetical rewards have typically been employed, subjects in the present study were entered into a lottery in which they had a chance of actually receiving one of their choices. The delayed rewards were grouped into small ($30-$35), medium ($55-$65), and large amounts ($70-$85). Using a novel parameter estimation procedure, we estimated discounting rates for all three reward sizes for each subject on the basis of his/her pattern of choices. The data indicated that the discounting rate is a decreasing function of the size of the delayed reward (p < .0001), whether hyperbolic or exponential discounting functions are assumed. In addition, a reliable gender difference was found (p = .005), with males discounting at higher rates than females, on average.
812 citations
TL;DR: Predictions relative to which species will invade and when they will invade can be improved by more detailed attention to these six categories of interrelated processes that mediate invasion success.
591 citations
TL;DR: The authors showed that false incriminating evidence can lead people to accept guilt for a crime they did not commit, and found that subjects in the fast-pace/witness group were more likely to sign a confession, internalize guilt for the event, and confabulate details in memory consistent with that belief.
Abstract: An experiment demonstrated that false incriminating evidence can lead people to accept guilt for a crime they did not commit Subjects in a fast- or slow-paced reaction time task were accused of damaging a computer by pressing the wrong key All were truly innocent and initially denied the charge A confederate then said she saw the subject hit the key or did not see the subject hit the key Compared with subjects in the slow-pacelno-witness group, those in the fast-pace/witness group were more likely to sign a confession, internalize guilt for the event, and confabulate details in memory consistent with that belief Both legal and conceptual implications are discussed
451 citations
TL;DR: This article examined why suspicion of ulterior motives leads perceivers to avoid the correspondence bias in the assigned-essay paradigm, in contrast to information about situational constraint, and showed that the effects of suspicion can endure across targets and contexts.
Abstract: This research examined why suspicion of ulterior motives leads perceivers to avoid the correspondence bias in the assigned-essay paradigm, in contrast to information about situational constraint. Five experiments offer converging evidence that suspicion triggers active, sophisticated attributional thinking. These studies examined participants' spontaneous thoughts and attributional analyses in the context of high-constraint or ulterior-motives conditions. The studies (a) suggest that high-constraint information and ulterior-motive information have divergent effects on perceivers early in the inference process, (b) demonstrate the correspondence bias in instances in which demand characteristics are minimized, and (c) show that the effects of suspicion can endure across targets and contexts. The implications of these results for current models of the correspondence bias and the dispositional inference process, and suggestions for a revised model, are discussed.
344 citations
TL;DR: The authors assesses the perils of cultural accounts centered on resistance in particular and on the problem of power in general, through a brief examination of two ethnographic cases from radically different social worlds.
Abstract: The concept of resistance has become one of anthropology's dominant theoretical preoccupations - so influential, in fact, that it threatens to overshadow other aspects of social life, to the detriment of our understanding of cultural complexity and creativity. Through a brief examination of two ethnographic cases from radically different social worlds, this essay assesses the perils of cultural accounts centered on resistance in particular and on the problem of power in general
308 citations
TL;DR: A census reveals that fully one-third of the international governmental organizations (IGO) in existence in 1981 had in fact become defunct by 1992 as mentioned in this paper, and during this period a slightly larger number of new organizations was born.
Abstract: Hardly anyone expects public institutions to die. Yet a census reveals that fully one-third of the international governmental organizations (IGOs) in existence in 1981 had in fact become defunct by 1992. Most Eastern bloc and many regional developing country organizations vanished or became inactive. During this period a slightly larger number of new organizations was born. Not governments but other IGOs spawned most of the new offspring. Wealthy democratic countries increased their IGO memberships while poor unstable countries increasingly dropped out. This bifurcation was accompanied by greater reliance by all on a set of core universal-membership institutions dominated by Western values. Functionalism, organizational ecology, and realism each partly help us to understand these trends but leave important dynamics unexplained.
276 citations
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TL;DR: A complete recriminalization of abortion nationwide could result in 440,000 additional births per year, and a reversal of the Roe v Wade decision leaving abortion legal in some states would substantially limit this impact because of the extent of travel between states.
Abstract: We consider the effect of abortion legalization on births in the United States. A simple theoretical model demonstrates that the impact of abortion legalization on the birth rate is ambiguous, because both pregnancy and abortion decisions could be affected. We use variation in the timing of legalization across states in the early 1970's to estimate the effect of abortion on birth rates. Our findings indicate that states legalizing abortion experienced a 5% decline in births relative to other states. The decline among teens, women over 35, and nonwhite women was even greater: 13%, 8%, and 12% respectively. Out-of-wedlock births declined by twice as much as births in wedlock. If legalization in some states affected birth rates in neighboring states (through travel to obtain an abortion), comparing births between states will underestimate the actual reduction. Using more distant comparison states increases the estimated impact of abortion legalization on birth rates to about 8%. Applying this estimate to the current level of births, a complete recriminalization of abortion would result in 320,000 additional births per year.
150 citations
TL;DR: In this article, the authors consider whether state Medicaid abortion funding restrictions affect the likelihood of getting pregnant, having an abortion and bearing a child, and show that the response is concentrated among the low-income population.
113 citations
TL;DR: Although the ecological impacts of the invaders in the Hudson River basin have not been well studied, it is believed that about 10% of the exotic species, have had major ecological impacts in the basin.
Abstract: We compiled information about the distribution of exotic organisms in the fresh waters of the Hudson River basin. At least 113 nonindigenous species of vertebrates, vascular plants, and large invertebrates have established populations in the basin. Too little was known about the past or present distributions of algae and most small invertebrates to identify exotic species in these groups. Most established exotic species in the Hudson River basin originated from Eurasia or the Mississippi-Great Lakes basins, and were associated with vectors such as unintentional, releases (especially escapes from cultivation), shipping activities (especially, solid ballast or ballast water), canals, or intentional releases. Rates of species invasions of fresh and oligohaline waters in the basin have been high (ca. one new species per year) since about 1840. For many well-studied groups, introduced species constitute 4% to nearly 60% of the species now in the basin. Although the ecological impacts of the invaders in the Hudson River basin have not been well studied, we believe that about 10% of the exotic species, have had major ecological impacts in the basin. Since, the rates, of entry and composition of exotic species in the Hudson basin are similar to those observed., previously for the Laurentian Great Lakes, invasions tended to occur earlier in the Hudson basin, probably reflecting the earlier history of human commerce. While most exotics have had negative impacts on local flora and fauna, some fish species have provided unique angling opportunities and important economic benefits.
TL;DR: A new result limiting the amount of accessible information in a quantum channel is proved, which generalizes Kholevo{close_quote}s theorem and implies it as a simple corollary.
Abstract: We prove a new result limiting the amount of accessible information in a quantum channel This generalizes Kholevo's theorem and implies it as a simple corollary Our proof uses the strong subadditivity of the von Neumann entropy functional $S(\ensuremath{\rho})$ and a specific physical analysis of the measurement process The result presented here has application in information obtained from ``weak'' measurements, such as those sometimes considered in quantum cryptography
TL;DR: The corticohippocampal model successfully accounts for the effects of scopolamine in retarding classical conditioning in humans and animals and predicts that although cholinergic agonists (such as Tacrine) may improve learning in subjects with artificially depressed brain acetylcholine levels, there may be limited memory improvement in normal subjects from such Cholinergic therapy.
TL;DR: The DinR protein is structurally and functionally analogous to the E. coli LexA protein, and accordingly, it is proposed to be renaming the protein B. subtilis LexA.
TL;DR: In this paper, rate coefficients for electronic quenching of NO A2Σ+ (ν = 0) by CO, CO 2, H2, H 2O, O2, NO, N2O, NO2, and Ar measured at room temperature and at elevated temperatures behind reproducible shocks.
TL;DR: Collapsing across age groups, there is a general tendency for animals to acquire trace conditioning more slowly than delay conditioning, and in the delay and long-delay paradigms, significant conditioning deficits first appeared in the 4(+)-year-old group.
Abstract: Young (0.5 years) and aged (2+, 3+, and 4+ years) rabbits underwent acquisition of the classically conditioned nictitating membrane response in a delay (500-ms conditioned stimulus [CS], 400-ms interstimulus interval [ISI]), long-delay (1,000-ms CS, 900-ms ISI), or trace (500-ms CS, 400-ms stimulus-free period) paradigm. Collapsing across age groups, there is a general tendency for animals to acquire trace conditioning more slowly than delay conditioning. Collapsing across conditioning paradigms, there is a general tendency for aged animals to acquire more slowly than younger animals. Of greater significance, however, are the age differences in the different conditioning paradigms. In the delay and long-delay paradigms, significant conditioning deficits first appeared in the 4(+)-year-old group. In the trace conditioning paradigm, significant conditioning deficits became apparent in the 2(+)-year-old animals.
TL;DR: The characterization of Gabriel graphs settles several conjectures of Matula and Sokal and gives rise to linear-time algorithms for determining whether a tree has such a drawing.
Abstract: Complete characterizations are given for those trees that can be drawn as either the relative neighborhood graph, relatively closest graph, Gabriel graph, or modified Gabriel graph of a set of points in the plane. The characterizations give rise to linear-time algorithms for determining whether a tree has such a drawing; if such a drawing exists one can be constructed in linear time in the real RAM model. The characterization of Gabriel graphs settles several conjectures of Matula and Sokal [17].
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TL;DR: In this paper, the authors investigated whether the link in mother-daughter welfare participation is a causal relationship or whether it can be explained by the expected intergenerational correlation in earnings.
Abstract: Several recent studies have shown that daughters whose mothers have participated in the welfare program Aid to Families with Dependent Children (AFDC) are themselves more likely to participate in AFDC when they head their own household. Other studies have shown that the earnings of parents and their children are highly correlated across generations. This suggests that any variable correlated with income, such as AFDC participation, will also be correlated across generations. This paper uses data from the original and youth cohorts of the National Longitudinal Surveys to investigate the question of whether the link in mother-daughter welfare participation is a causal relationship or whether it can be explained by the expected intergenerational correlation in earnings. Several reduced-form probit equations are estimated, and attention is directed to the potential endogeneity of key explanatory variables. The empirical findings suggest that much of the observed correlation in AFDC participation across generations can be explained by the intergenerational correlation of income and other family characteristics.
TL;DR: In this article, Stratigraphic relationships and radiocarbon age constraints indicate that three separate landslide-dammed lakes formed between 13.7 and 12.4 cm in the late Pleistocene, with an estimated maximum depth of 30 m, a length of 13 km, and an initial volume of 2.7 km.
Abstract: Massive slump complexes composed of Pliocene basaltic rocks and underlying Miocene and Pliocene sediments flank the Rio Grande along 16 km of northern White Rock Canyon, New Mexico. The toe area of at least one slump complex was active in the late Pleistocene, damming the Rio Grande at least four times during the period from 18 to 12 {sup 14}C ka and impounding lakes that extended 10-20 km upriver. Stratigraphic relationships and radiocarbon age constraints indicate that three separate lakes formed between 13.7 and 12.4 {sup 14}C ka. The age and dimensions of the ca. 12.4 ka lake are best constrained; it had an estimated maximum depth of {approx}30 m, a length of {approx}13 km, a surface area of {approx}2.7 km{sup 2}, and an initial volume of {approx}2.5 x 10{sup 7} m{sup 3}. The youngest landslide-dammed lakes formed during a period of significantly wetter regional climate, strongly suggesting that climate changes were responsible for reactivation of the slump complexes. We are not certain about the exact triggering mechanisms for these landslides, but they probably involved removal of lateral support due to erosion of the slope base by the Rio Grande during periods of exceptionally high flood discharge or rapid incision;more » increased pore pressures associated with higher water tables; higher seepage forces at sites of ground-water discharge; or some combination of these processes. Seismic shaking could also have contributed to triggering of some of the landslides, particularly if aided by wet antecedent conditions. 54 refs., 19 figs., 3 tabs.« less
TL;DR: In this article, statistical factor analysis and related methods are used for statistical quality analysis in the context of quality assurance. But they do not address the problem of privacy in the analysis.
Abstract: (1996). Statistical Factor Analysis and Related Methods. Journal of Quality Technology: Vol. 28, No. 1, pp. 132-132.
TL;DR: For example, the U.S. total fertility rate settled into the doldrums, hovering around 1.8 for the better part of the 1970s and 1980s as discussed by the authors.
Abstract: Following its heart-stopping roller coaster ride in the decades after World War II, the U.S. total fertility rate settled into the doldrums, hovering around 1.8 for the better part of the 1970s and 1980s. The economy rose and fell, taking with it wages and employment rates; the baby boom gradually assumed its place in the labor force as the focus shifted to the baby bust generation; and female labor force participation rates continued to climb — but the fertility rate stolidly refused to budge significantly in either direction. Why bother trying to model something that isn’t moving? In the United States the ‘official response’ to fertility patterns over the past two decades is summed up well in the following statement from Patrick Thompson et al. (1989):
TL;DR: The AMS Special Session on Soap Bubble Geometry (SBSG) as mentioned in this paper was organized by Frank Morgan, and participants in the special session included the following: Fred Almgren, Princeton U. Megan Barber, Williams C. John Cahn, NIST Joel Foisy, Duke U. Jenny Kelley, Rutgers U.
Abstract: The Burlington Mathfest in August 1995 included an AMS Special Session on Soap Bubble Geometry, organized by Frank Morgan. At the end of the session, participants were asked to pose open problems related to bubble geometry. We have collected those problems here, adding a few introductory comments. Participants in the special session included the following: Fred Almgren, Princeton U. Megan Barber, Williams C. Ken Brakke, Susquehanna U. John Cahn, NIST Joel Foisy, Duke U. Christopher French, U.Chicago Scott Greenleaf, SUNY Stony Brook Karsten Groes-Brauckmann, Bonn Joel Hass, UC Davis Aladar Heppes, Budapest Michael Hutchings, Harvard U. Jenny Kelley, Rutgers U. Andy Kraynik, Sandia Rob Kusner, U.Massachusetts Rafael Lopez, Granada Joe Masters, U.Texas Helen Moore, Bowdoin C. Frank Morgan, Williams C. Ivars Peterson, Science News Robert Phelan, Dublin Joel Shore, McGill U. John Sullivan, U.Minnesota Italo Tamanini, Trento Jean Taylor, Rutgers U. Jennifer Tice, Williams C. Brian Wecht, Williams C. Henry Wente, U.Toledo Brian White, Stanford U.
TL;DR: The results suggest that the neuroactive steroid pregnenolone sulfate may play an independent role in the stress response after maternal separation as well as being a precursor for the anxiolytic neurosteroid allopregnanolone.
Abstract: Fetal alcohol exposure has been reported to be associated with hyper-responsiveness to stress. Using a maternal separation paradigm, this study examined whether prenatal alcohol exposure affected sensitivity to neurosteroid modulation of stress. We have shown that the neuroactive steroid allopregnanolone reduces ultrasonic vocalizations (USVs) after brief maternal separation in week-old rat pups. Prenatal alcohol exposure, however, resulted in reduced sensitivity to this neurosteroid. In this study's first experiment, the behavioral effects of pregnenolone sulfate, a neurosteroid with reportedly opposite modulatory effects on the GABAA receptor, were characterized. Pregnenolone sulfate had a triphasic effect on the production of ultrasonic vocalizations and on open field activity. Blockade of conversion of pregnenolone sulfate to allopregnanolone via the 5 alpha-reductase inhibitor 4-MA also blocked the drug-related reduction in USVs, but not the higher-dose augmentation. The enzyme inhibitor alone had no significant effects on USV production, nor did progesterone. These results suggest that the neuroactive steroid pregnenolone sulfate may play an independent role in the stress response after maternal separation as well as being a precursor for the anxiolytic neurosteroid allopregnanolone. In the second experiment, prenatal alcohol exposure was found to eliminate both the low dose USV-reducing effect and the higher dose USV-increasing effect. These results support previous results demonstrating that prenatal alcohol exposure may cause an altered sensitivity to the neuromodulatory effects of neurosteroids.
TL;DR: In this paper, it was shown that the upper and lower tunnels in 2-bridge knot and link complements must be isotopic to geodesics of length at most ln(4), where length is measured relative to maximal cusps.
Abstract: We give a complete classification of the unknotting tunnels in 2-bridge link complements, proving that only the upper and lower tunnels are unknotting tunnels. Moreover, we show that the only strongly parabolic tunnels in 2-cusped hyperbolic 3-manifolds are exactly the upper and lower tunnels in 2-bridge knot and link complements. From this, it follows that the upper and lower tunnels in 2-bridge knot and link complements must be isotopic to geodesics of length at most ln(4), where length is measured relative to maximal cusps. Moreover, the four dual unknotting tunnels in a 2-bridge knot complement, which together with the upper and lower tunnels form the set of all known unknotting tunnels for these knots, must each be homotopic to a geodesic of length at most 6ln(2).
TL;DR: The ability of glucose to reverse impairments following intra-amygdala injections of morphine but not propranolol may reflect the neurotransmitter system or systems through which glucose exerts its effects.
Abstract: Both systemic and central injections of glucose can enhance memory. For example, glucose reverses impairments on inhibitory avoidance resulting from intra-amygdala injections of morphine. The present experiment investigated the ability of glucose to reverse memory impairments resulting from intra-amygdala injections of propranolol, a beta-noradrenergic antagonist. Pretraining administration of 10 microg propranolol significantly reduced inhibitory avoidance retention latencies but had no effect on performance in a spontaneous alternation task. Coadministration of glucose into the amygdala at 3 doses (1.5, 3.0, and 6.0 microg) did not reverse the propranolol-induced inhibitory avoidance deficits. However, coadministration of 2.5 microg of glutamate with the propranolol did reverse these deficits. The ability of glucose to reverse impairments following intra-amygdala injections of morphine but not propranolol may reflect the neurotransmitter system or systems through which glucose exerts its effects.
TL;DR: The literature on risk management by agricultural households has made important contributions to our understanding of household-level economic decisions in developing countries as discussed by the authors, which can explain behavior observed in peasant households.
Abstract: The literature on risk management by agricultural households has made important contributions to our understanding of household-level economic decisions in developing countries. Because incomes from particular farming enterprises fluctuate widely depending on weather, crop prices, and macroeconomic policies, households adopt a number of strategies to smooth their consumption. One approach is to diversify the sources of income for the household. The members of peasant households may engage in farming, trading and other business activities, and wage labor (Reardon, Delgado, and Matlon). When household members are involved in multiple activities and pool their income, total household income may be less subject to extreme variation. Morduch notes "mitigating risk through production choices can be costly since typically expected profits must be sacrificed for lower risk" (p. 104). This approach to risk management may be costly for the household. Over the past three decades, economists have used theories of household risk management and consumption smoothing to explain behavior observed in peasant households. For example, the purchase and sale of assets are frequently used as a means of savings and consumption smoothing when there are limited formal financial institutions. Marriage decisions may establish kin relationships with people in areas that experience different weather and production shocks (Rosenzweig and Stark). Although it may seem inefficient for households to farm numerous small plots that are widely scattered, this strategy provides some protection against location-specific crop failures from bad weather or pests (McClosky, Walker and Ryan). The extensive literature on contracting and sharecropping arrangements focuses on the role that these institutions play in minimizing a household's exposure to risk (Hoff, Braverman, and Stiglitz). All of these theories assume that households
TL;DR: In this article, the authors focus on the microeconomic behavior of poor households when returns to labor are sufficiently high, poor households can intensify their work effort to generate additional income that in turn provides funds for high-return investments; under these circumstances the marginal propensity to save from this additional income may be exceptionally high.
Abstract: New empirical evidence suggests that high levels of income inequality constrain rather than encourage growth While some explanations involve relationships between inequality and political systems, this paper focuses on the microeconomic behavior of poor households When returns to labor are sufficiently high, poor households can intensify their work effort to generate additional income that in turn provides funds for high-return investments; under these circumstances the marginal propensity to save from this additional income may be exceptionally high Increased savings and investment among the poor can, in turn, simultaneously reduce poverty and income inequality and stimulate growth The model developed in this paper is applied to human capital investment in Brazil and Korea from 1960 to 1990
TL;DR: The insects that showed delayed responses to fertilizer treatment may have been affected by changes in microclimate that developed slowly over the course of the study, suggesting that long‐term studies may be necessary to detect effects of host plant stress on insect herbivores.
Abstract: .
1
The densities of insect herbivores in fertilized and unfertilized field plots of goldenrods, Solidago altissima (Compositae), were monitored over a period of 4 years.
2
A total of seventeen insect taxa occurred on the plots over the course of the study, including sap feeders, leaf chewers, leaf miners, leaf gallers and stem gallers with multiple representatives in each of these feeding guilds.
3
Nine of the seventeen taxa significantly increased in density on fertilized plots in at least one year of the study, two taxa showed marginally significant increases on fertilized plots, two significantly decreased in density on fertilized plots in at least one year, and the remaining taxa were unaffected by the fertilizer treatment.
4
The effects of fertilization on the insects were not strongly related to feeding guild; the group of insects that increased on fertilized plots was functionally diverse, and for the most part members of the same guild did not respond to the fertilizer treatment in consistent ways.
5
Differences between fertilized and unfertilized plots were greatest in the fourth year. The insects that showed delayed responses to fertilizer treatment may have been affected by changes in microclimate that developed slowly over the course of the study, suggesting that long-term studies may be necessary to detect effects of host plant stress on insect herbivores.
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TL;DR: In the case of Argentina, the central bank is both the lender of last resort and the currency board, providing full convertibility between pesos and U.S. dollars as discussed by the authors.
Abstract: No grand solution appears to exist for the problems that seem inevitable in the Argentine system, in which the Central Bank is both lender of last resort and currency board, providing full convertibility between pesos and U.S. dollars. Argentina's strategy therefore must turn on actively strengthening its banking systems to reduce solvency risks and on building its reserves. Within the current rules of the game, Argentina's central bank (BCRA) is charged with being the lender of last resort as well as providing full convertibility between pesos and U.S. dollars - two objectives with one instrument, namely, reserves. Within those rules, it may well be that the balance of responsibilities needs to shift. Complete dollarization can significantly reduce risks but not entirely eliminate them. If the BCRA can concentrate more on building up reserves and helping to ward off crises of confidence in the currency, perhaps the banking system can protect itself better from liquidity shocks. But this will require, among other things, consolidation of the sector (which could give it greater access to outside liquidity) and prudential strengthening of the system. Triage of weaker banks should continue and not await another crisis. More experience with the new liquidity policy is needed and so is reform of the settlement system, as it affects the functioning of the interbank market, which is essential for containing crises. Essentially, however, no grand solution seems to exist for the problems that seem inevitable in a system where the central bank is also the currency board. Argentina's strategy must therefore turn on actively strengthening its banking systems to reduce the risks of insolvency. This paper - a product of the Finance and Private Sector Development Division, Policy Research Department - is part of a larger effort in the department to advise member countries on financial sector policy.