Showing papers by "University of Bologna published in 2004"

A Molecular Elevator

Abstract: We report the incrementally staged design, synthesis, characterization, and operation of a molecular machine that behaves like a nanoscale elevator. The operation of this device, which is made of a platformlike component interlocked with a trifurcated riglike component and is only 3.5 nanometers by 2.5 nanometers in size, relies on the integration of several structural and functional molecular subunits. This molecular elevator is considerably more complex and better organized than previously reported artificial molecular machines. It exhibits a clear-cut on-off reversible behavior, and it could develop forces up to around 200 piconewtons.

Polymer nanocomposites as dielectrics and electrical insulation-perspectives for processing technologies, material characterization and future applications

Abstract: Polymer nanocomposites are defined as polymers in which small amounts of nanometer size fillers are homogeneously dispersed by only several weight percentages. Addition of just a few weight percent of the nanofillers has profound impact on the physical, chemical, mechanical and electrical properties of polymers. Such change is often favorable for engineering purpose. This nanocomposite technology has emerged from the field of engineering plastics, and potentially expanded its application to structural materials, coatings, and packaging to medical/biomedical products, and electronic and photonic devices. Recently these 'hi-tech' materials with excellent properties have begun to attract research people in the field of dielectrics and electrical insulation. Since new properties are brought about from the interactions of nanofillers with polymer matrices, mesoscopic properties are expected to come out, which would be interesting to both scientists and engineers. Improved characteristics are. expected as dielectrics and electrical insulation. Several interesting results to indicate the foreseeable future have been revealed, some of which are described on materials and processing in the paper together with basic concepts and future direction.

A double-pulsar system: A rare laboratory for relativistic gravity and plasma physics

Abstract: The clocklike properties of pulsars moving in the gravitational fields of their unseen neutron-star companions have allowed unique tests of general relativity and provided evidence for gravitational radiation. We report here the detection of the 2.8-second pulsar J07373039B as the companion to the 23-millisecond pulsar J07373039A in a highly relativistic double neutron star system, allowing unprecedented tests of fundamental gravitational physics. We observed a short eclipse of J07373039A by J07373039B and orbital modulation of the flux density and the pulse shape of J07373039B, probably because of the influence of J07373039A’s energy flux on its magnetosphere. These effects will allow us to probe magneto-ionic properties of a pulsar magnetosphere. Double neutron star (DNS) binaries are rare, and only six such systems are known. How

New Catalytic Approaches in the Stereoselective Friedel–Crafts Alkylation Reaction

Abstract: After more than 125 years, the Friedel-Crafts alkylation is still one of the most studied and most utilized reactions in organic synthesis. What is the secret of this astonishing success? Perhaps the great versatility in scope and applicability continues to justify its crucial role in the synthesis of more and more complex molecules. However, it has taken more than a century for asymmetric catalytic versions of this reaction to be developed and subsequently extended to a range of aromatic compounds and alkylating agents. Herein we review recent developments in the design and use of catalytic and stereoselective strategies for the alkylation of aromatic systems and synthesis of a wide range of polyfunctionalized enantiomerically enriched compounds.

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature.

Abstract: Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years) A long history of OO was common The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9) The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 17 to 14 cm Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification Four of these benign-appearing PMTMCTs contained osteoid-like matrix Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant The 3 cases without known OO were histologically identical to the typical PMTMCT Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma Three cases expressed actin; all other markers were negative Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases) We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors Recognition of PMTMCT is critical, as complete resection cures intractable OO Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO

Formal molecular biology

Abstract: A language of formal proteins, the K-calculus, is introduced. Interactions are modeled at the domain level, bonds are represented by means of shared names, and reactions are required to satisfy a causality requirement of monotonicity.An example of a simplified signalling pathway is introduced to illustrate how standard biological events can be expressed in our protein language. A more comprehensive example, the lactose operon, is also developed, bringing some confidence in the formalism considered as a modeling language.Then a finer-grained concurrent model, the mK-calculus, is considered, where interactions have to be at most binary. We show how to embed the coarser-grained language in the latter, a properly which we call self-assembly.Finally we show how the finer-grained language can itself be encoded in π-calculus, a standard foundational language for concurrency theory.

Hemispatial neglect Subtypes, neuroanatomy, and disability

Abstract: Objective: To assess the relative frequency of occurrence of motor, perceptual, peripersonal, and personal neglect subtypes, the association of neglect and other related deficits (e.g., deficient nonlateralized attention, anosognosia), and the neuroanatomic substrates of neglect in patients with right hemisphere stroke in rehabilitation settings. Methods: The authors assessed 166 rehabilitation inpatients and outpatients with right hemisphere stroke with measures of neglect and neglect subtypes, attention, motor and sensory function, functional disability, and family burden. Detailed lesion analyses were also performed. Results: Neglect was present in 48% of right hemisphere stroke patients. Patients with neglect had more motor impairment, sensory dysfunction, visual extinction, basic (nonlateralized) attention deficit, and anosognosia than did patients without neglect. Personal neglect occurred in 1% and peripersonal neglect in 27%, motor neglect in 17%, and perceptual neglect in 21%. Neglect severity predicted scores on the Functional Independence Measure and Family Burden Questionnaire more accurately than did number of lesioned regions. Conclusions: The neglect syndrome per se, rather than overall stroke severity, predicts poor outcome in right hemisphere stroke. Dissociations between tasks assessing neglect subtypes support the existence of these subtypes. Finally, neglect results from lesions at various loci within a distributed system mediating several aspects of attention and spatiomotor performance.

The endothelin system in pulmonary arterial hypertension

Abstract: Endothelin-1 (ET-1), a peptide produced primarily by vascular endothelial cells, was discovered in 1980 and it was characterized as a powerful vasoconstrictor and mitogen for smooth muscle. ET-1 binds to two types of receptors, ETA and ETB: ETA-receptors are found in smooth muscle cells, whereas ETB-receptors are localized on both endothelial cells and in smooth muscle cells. Activation of ETA- and ETB-receptors on smooth muscle cells mediates the vasoconstrictive and mitogenic effects of ET-1. Stimulation of endothelial ETB-receptors promotes ET-1 clearance and activation of NO and prostacyclin release. Pulmonary arterial hypertension (PAH) is a severe condition characterized by a progressive increase in pulmonary vascular resistance leading to right ventricular failure and death. An activation of the ET-1 system has been demonstrated in both plasma and lung tissues of PAH patients as well as in animal models of PAH. The most efficient way to antagonize the ET-1 system is the use of ET-1 receptor antagonists that can block either ETA- or ETA- and ETB-receptors. These drugs are effective in animal models of PAH and have been tested in multiple clinical trials in patients with PAH. Bosentan, an orally active, dual ET-1 receptor antagonist has been shown to improve symptoms, exercise capacity, hemodynamics, echocardiographic parameters and the outcome of patients with severe PAH, and it has been approved for clinical use in many countries. The selective ETA-receptor antagonist sitaxentan has improved exercise capacity and hemodynamics of PAH patients in two preliminary studies. The main side effect of ET-1 antagonists is the increase of liver enzymes likely due to an accumulation of bile salts cytotoxic to hepatocytes. Additional trials with these drugs are currently ongoing. In conclusion, the hypothesis that the ET-1 system over-activation can be successfully antagonised in patients with PAH has been clearly demonstrated.

FVC2004: Third Fingerprint Verification Competition

Abstract: A new technology evaluation of fingerprint verification algorithms has been organized following the approach of the previous FVC2000 and FVC2002 evaluations, with the aim of tracking the quickly evolving state-of-the-art of fingerprint recognition systems. Three sensors have been used for data collection, including a solid state sweeping sensor, and two optical sensors of different characteristics. The competition included a new category dedicated to ”light” systems, characterized by limited computational and storage resources. This paper summarizes the main activities of the FVC2004 organization and provides a first overview of the evaluation. Results will be further elaborated and officially presented at the International Conference on Biometric Authentication (Hong Kong) on July 2004.

Diagnostic Real-Time PCR for Detection of Salmonella in Food

Abstract: A robust 5′ nuclease (TaqMan) real-time PCR was developed and validated in-house for the specific detection of Salmonella in food The assay used specifically designed primers and a probe target within the ttrRSBCA locus, which is located near the Salmonella pathogenicity island 2 at centisome 305 It is required for tetrathionate respiration in Salmonella The assay correctly identified all 110 Salmonella strains and 87 non-Salmonella strains tested An internal amplification control, which is coamplified with the same primers as the Salmonella DNA, was also included in the assay The detection probabilities were 70% when a Salmonella cell suspension containing 103 CFU/ml was used as a template in the PCR (5 CFU per reaction) and 100% when a suspension of 104 CFU/ml was used A pre-PCR sample preparation protocol including a preenrichment step in buffered peptone water followed by DNA extraction-purification was applied when 110 various food samples (chicken rinses, minced meat, fish, and raw milk) were investigated for Salmonella The diagnostic accuracy was shown to be 100% compared to the traditional culture method The overall analysis time of the PCR method was approximately 24 h, in contrast to 4 to 5 days of analysis time for the traditional culture method This methodology can contribute to meeting the increasing demand of quality assurance laboratories for standard diagnostic methods Studies are planned to assess the interlaboratory performance of this diagnostic PCR method

ConSeq: the identification of functionally and structurally important residues in protein sequences

Abstract: Motivation: ConSeq is a web server for the identification of biologically important residues in protein sequences. Functionally important residues that take part, e.g. in ligand binding and protein--protein interactions, are often evolutionarily conserved and are most likely to be solvent-accessible, whereas conserved residues within the protein core most probably have an important structural role in maintaining the protein's fold. Thus, estimated evolutionary rates, as well as relative solvent accessibility predictions, are assigned to each amino acid in the sequence; both are subsequently used to indicate residues that have potential structural or functional importance. Availability: The ConSeq web server is available at http://conseq.bioinfo.tau.ac.il/ Supplementary information: The ConSeq methodology, a description of its performance in a set of five well-documented proteins, a comparison to other methods, and the outcome of its application to a set of 111 proteins of unknown function, are presented at http://conseq.bioinfo.tau.ac.il/ under 'OVERVIEW', 'VALIDATION', 'COMPARISON' and 'PREDICTIONS', respectively.

Observation of the narrow state X(3872) → J/ψπ+π- in p̄p collisions at √s = 1.96 TeV

Abstract: The observation of a state consistent with X(3872) decaying into J/ψπ+π- was reported. The X(3872) mass was measured to be 3871.3±0.7(stat)±0.4(syst)MeV/c2 from a sample of 730±90 candidates. The observed width was consistent with the detector resolution. The results were found to be converging well with the measurements by the Belle Collaboration using b± decays.

The Molecular Dissection of mtDNA Haplogroup H Confirms That the Franco-Cantabrian Glacial Refuge Was a Major Source for the European Gene Pool

Abstract: Complete sequencing of 62 mitochondrial DNAs (mtDNAs) belonging (or very closely related) to haplogroup H revealed that this mtDNA haplogroup—by far the most common in Europe—is subdivided into numerous subhaplogroups, with at least 15 of them (H1–H15) identifiable by characteristic mutations. All the haplogroup H mtDNAs found in 5,743 subjects from 43 populations were then screened for diagnostic markers of subhaplogroups H1 and H3. This survey showed that both subhaplogroups display frequency peaks, centered in Iberia and surrounding areas, with distributions declining toward the northeast and southeast—a pattern extremely similar to that previously reported for mtDNA haplogroup V. Furthermore, the coalescence ages of H1 and H3 (∼11,000 years) are close to that previously reported for V. These findings have major implications for the origin of Europeans, since they attest that the Franco-Cantabrian refuge area was indeed the source of late-glacial expansions of hunter-gatherers that repopulated much of Central and Northern Europe from ∼15,000 years ago. This has also some implications for disease studies. For instance, the high occurrence of H1 and H3 in Iberia led us to re-evaluate the haplogroup distribution in 50 Spanish families affected by nonsyndromic sensorineural deafness due to the A1555G mutation. The survey revealed that the previously reported excess of H among these families is caused entirely by H3 and is due to a major, probably nonrecent, founder event.

Magnetic fields in clusters of galaxies

Abstract: The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. Magnetic fields are investigated in the radio band from studies of the rotation measure of polarized radio galaxies and the synchrotron emission of cluster-wide diffuse sources. Other techniques include X-ray studies of the inverse Compton emission and of cold fronts and magneto hydrodynamic simulations. We review the main issues that have led to our knowledge on magnetic fields in clusters of galaxies. Observations show that cluster fields are at the μG level, with values up to tens of μG at the center of cooling core clusters. Estimates obtained from different observational approaches may differ by about an order of magnitude. However, the discrepancy may be alleviated by considering that the magnetic field is not constant throughout the cluster, and shows a complex structure. In particular, the magnetic field intensity declines with the cluster ...

Comparing the temperatures of galaxy clusters from hydrodynamical N-body simulations to Chandra and XMM-Newton observations

Abstract: Theoretical studies of the physical processes guiding the formation and evolution of galaxies and galaxy clusters in the X-ray region are mainly based on the results of numerical hydrodynamical N-body simulations, which in turn are often directly compared with X-ray observations. Although trivial in principle, these comparisons are not always simple. We demonstrate that the projected spectroscopic temperature of thermally complex clusters obtained from X-ray observations is always lower than the emission-weighed temperature, which is widely used in the analysis of numerical simulations. We show that this temperature bias is mainly related to the fact that the emission-weighted temperature does not reflect the actual spectral properties of the observed source. This has important implications for the study of thermal structures in clusters, especially when strong temperature gradients, such as shock fronts, are present. Because of this bias, in real observations shock fronts appear much weaker than what is predicted by emission-weighted temperature maps, and may not even be detected. This may explain why, although numerical simulations predict that shock fronts are a quite common feature in clusters of galaxies, to date there are very few observations of objects in which they are clearly seen. To fix this problem we propose a new formula, the spectroscopic-like temperature function, and show that, for temperatures higher than 3 keV, it approximates the spectroscopic temperature to better than a few per cent, making simulations more directly comparable to observations.

Beyond data warehousing: what's next in business intelligence?

Abstract: During the last ten years the approach to business management has deeply changed, and companies have understood the importance of enforcing achievement of the goals defined by their strategy through metrics-driven management. The DW process, though supporting bottom-up extraction of information from data, fails in top-down enforcing the company strategy. A new approach to BI, called Business Performance Management (BPM), is emerging from this framework: it includes DW but it also requires a reactive component capable of monitoring the time-critical operational processes to allow tactical and operational decision-makers to tune their actions according to the company strategy. The aim of this paper is to encourage the research community to acknowledge the coming of a second era in BI, to propose a general architecture for BPM, and to lay the premises for investigating the most challenging of the related issues.

Xpipes: a network-on-chip architecture for gigascale systems-on-chip

Abstract: The growing complexity of embedded multiprocessor architectures for digital media processing will soon require highly scalable communication infrastructures. Packet switched networks-on-chip (NoC) have been proposed to support the trend for systems-on-chip integration. In this paper, an advanced NoC architecture, called Xpipes, targeting high performance and reliable communication for on-chip multi-processors is introduced. It consists of a library of soft macros (switches, network interfaces and links) that are design-time composable and tunable so that domain-specific heterogeneous architectures can be instantiated and synthesized. Links can be pipelined with a flexible number of stages to decouple link throughput from its length and to get arbitrary topologies. Moreover, a tool called XpipesCompiler, which automatically instantiates a customized NoC from the library of soft network components, is used in this paper to test the Xpipes-based synthesis flow for domain-specific communication architectures.

X‐ray properties of galaxy clusters and groups from a cosmological hydrodynamical simulation

Abstract: We present results on the X-ray properties of clusters and groups of galaxies, extracted from a large cosmological hydrodynamical simulation. We used the TREE+SPH code GADGET to simulate a concordance A cold dark matter cosmological model within a box of 192 h -1 Mpc on a side, 480 3 dark matter particles and as many gas particles. The simulation includes radiative cooling assuming zero metallicity, star formation and supernova feedback. The very high dynamic range of the simulation allows us to cover a fairly large interval of cluster temperatures. We compute X-ray observables of the intracluster medium (ICM) for simulated groups and clusters and analyse their statistical properties. The simulated mass-temperature relation is consistent with observations once we mimic the procedure for mass estimates applied to real clusters. Also, with the adopted choices of Ω m = 0.3 and σ 8 = 0.8 for matter density and power spectrum normalization, respectively, the resulting X-ray temperature functton agrees with the most recent observational determinations. The luminosity-temperature relation also agrees with observations for clusters with T ≥ 2 keV. At the scale of groups, T ≥ 1 keV, we find no change of slope in this relation. The entropy in central cluster regions is higher than predicted by gravitational heating alone, the excess being almost the same for clusters and groups. We also find that the simulated clusters appear to have suffered some overcooling. We find f * ≃ 0.2 for the fraction of baryons in stars within clusters, thus approximately twice as large as the value observed. Interestingly, temperature profiles of simulated clusters are found to increase steadily toward cluster centres. They decrease in the outer regions, much like observational data do at r ≥ 0.2r vir , while not showing an isothermal regime followed by a smooth temperature decline in the innermost regions. Our results thus demonstrate the need for yet more efficient sources of energy feedback and/or the need to consider additional physical process which may be able to further suppress the gas density at the scale of poor clusters and groups, and, at the same time, to regulate the cooling of the ICM in central regions.

On the Mechanism of the cis−trans Isomerization in the Lowest Electronic States of Azobenzene: S0, S1, and T1

Abstract: In this paper, we identify the most efficient decay and isomerization route of the S1, T1, and S0 states of azobenzene. By use of quantum chemical methods, we have searched for the transition states (TS) on the S1 potential energy surface and for the S0/S1 conical intersections (CIs) that are closer to the minimum energy path on the S1. We found only one TS, at 60° of CNNC torsion from the E isomer, which requires an activation energy of only 2 kcal/mol. The lowest energy CIs, lying also 2 kcal/mol above the S1 minimum, were found on the torsion pathway for CNNC angles in the range 95−90°. The lowest CI along the inversion path was found ca. 25 kcal/mol higher than the S1 minimum and was characterized by a highly asymmetric molecular structure with one NNC angle of 174°. These results indicate that the S1 state decay involves mainly the torsion route and that the inversion mechanism may play a role only if the molecule is excited with an excess energy of at least 25 kcal/mol with respect to the S1 minimum...

Effect of information about benefits of biotechnology on consumer acceptance of genetically modified food: evidence from experimental auctions in the United States, England, and France

Abstract: This study investigates the effect of information about potential benefits of biotechnology on consumer acceptance of genetically modified (GM) foods. Consumer willingness to accept compensation to consume a GM food was elicited using an incentive compatible auction mechanism in three US states (California, Florida, and Texas) and in two European countries (England and France). Results indicate that information on environmental benefits, health benefits and benefits to the third world significantly decreased the amount of money consumers demanded to consume GM food; however, the effect of information varied by type of information and location. Consistent with prior research, we find that initial attitudes toward biotechnology have a significant effect on how individuals responded to new information.

Palmitoylation-dependent estrogen receptor α membrane localization: Regulation by 17β-estradiol

Abstract: A fraction of the nuclear estrogen receptor α (ERα) is localized to the plasma membrane region of 17β-estradiol (E2) target cells. We previously reported that ERα is a palmitoylated protein. To gain insight into the molecular mechanism of ERα residence at the plasma membrane, we tested both the role of palmitoylation and the impact of E2 stimulation on ERα membrane localization. The cancer cell lines expressing transfected or endogenous human ERα (HeLa and HepG2, respectively) or the ERα nonpalmitoylable Cys447Ala mutant transfected in HeLa cells were used as experimental models. We found that palmitoylation of ERα enacts ERα association with the plasma membrane, interaction with the membrane protein caveolin-1, and nongenomic activities, including activation of signaling pathways and cell proliferation (i.e., ERK and AKT activation, cyclin D1 promoter activity, DNA synthesis). Moreover, E2 reduces both ERα palmitoylation and its interaction with caveolin-1, in a time- and dose-dependent manner. These data point to the physiological role of ERα palmitoylation in the receptor localization to the cell membrane and in the regulation of the E2-induced cell proliferation.

Comparing the temperatures of galaxy clusters from hydro-N-body simulations to Chandra and XMM-Newton observations

Abstract: Theoretical studies of the physical processes in clusters of galaxies are mainly based on the results of numerical simulations, which in turn are often directly compared to X-ray observations. Although trivial in principle, these comparisons are not always simple. We show that the projected spectroscopic temperature of clusters obtained from X-ray observations is always lower than the emission-weighed temperature. This bias is related to the fact that the emission-weighted temperature does not reflect the actual spectral properties of the observed source. This has implications for the study of thermal structures in clusters, especially when strong temperature gradients, like shock fronts, are present. In real observations shock fronts appear much weaker than what is predicted by emission-weighted temperature maps. We propose a new formula, the spectroscopic-like temperature function that better approximates the spectroscopic temperature, making simulations more directly comparable to observations

TCP Hybla: a TCP enhancement for heterogeneous networks

Abstract: SUMMARY In heterogeneous networks, TCP connections that incorporate a terrestrial or satellite radio link are greatly disadvantaged with respect to entirely wired connections, because of their longer round trip times (RTTs). To cope with this problem, a new TCP proposal, the TCP Hybla, is presented and discussed in the paper. It stems from an analytical evaluation of the congestion window dynamics in the TCP standard versions (Tahoe, Reno, NewReno), which suggests the necessary modifications to remove the performance dependence on RTT. TCP Hybla performance is firstly evaluated in the case of an ideal channel, with good correlation between analytical and simulation data. Then, more realistic situations, which require the adoption of a benchmark network topology and a careful ns-2 simulation set-up, are examined. In particular, TCP Hybla performance is compared with that achievable by TCP standard in the presence of congestion and link losses, either separately or jointly considered. In all the examined cases, the superiority of TCP Hybla is evident, as it greatly reduces the severe penalization suffered by wireless, and especially satellite, TCP connections. Finally, it is worth noting that TCP Hybla does not infringe the end to end semantics of TCP and is compatible with other promising enhancements. Copyright # 2004 John Wiley & Sons, Ltd.

Six-year outcome of cognitive behavior therapy for prevention of recurrent depression.

Abstract: OBJECTIVE: A paucity of studies use nonpharmacological strategies for preventing recurrence in depression. Cognitive behavior treatment of residual symptoms was found to yield a significantly lower relapse rate than clinical management in recurrent depression at a 2-year follow-up. The objective of this investigation was to provide a 6-year follow-up of cognitive behavior treatment versus clinical management. METHOD: Forty patients with recurrent major depression who had been successfully treated with antidepressant drugs were randomly assigned to either cognitive behavior treatment of residual symptoms (supplemented by lifestyle modification and well-being therapy) or clinical management. In both groups, antidepressant drugs were tapered and discontinued. A 6-year follow-up was undertaken. During this period, no antidepressant drugs were used unless a relapse ensued. RESULTS: Cognitive behavior treatment resulted in a significantly lower relapse rate (40%) at a 6-year follow-up than did clinical manageme...