The effect of treatment with calcitonin on vertebral fracture rate in osteoporosis.

The efficacy of treatments for osteoporosis does not become evident when evaluated by fracture incidence (FI). Vertebral FI decreased in all controlled studies on calcitonin, but not significantly. Small sample sizes and short periods of treatment may have masked a possible therapeutic benefit, but longer, controlled studies with sodium fluoride or etidronate in larger groups of patients also failed to show a decrease in FI. The present analysis of nine published, therapeutic studies which indicate the FI per year and the initial prevalence of vertebral fractures, examines the question of whether the initial prevalence of fractures has an effect on the subsequent incidence of new fractures and whether the therapeutic effects have to be evaluated as a function of the initial prevalence of fractures. Bearing in mind the differences in roentgenological evaluation and in the size and quality of the various studies, the analysis revealed (1) that in the control groups there was a higher FI in patients with more than three vertebral fractures at baseline (estimated odds ratio (OR) = 49, p = 0.011); (2) that a similar trend, although not statistically significant, was observed in treated patients; (3) that the groups of control patients treated for more than 1 year showed in general an increase in FI beyond the first year and that the reverse was true in treated patients. In conclusion, failure to allow for the initial prevalence of vertebral fractures at the individual level in therapeutic trials of calcitonin to treat osteoporosis and prevent new fractures might have contributed to the absence of a demonstrable benefit of the treatment in those studies.

Effect of an I.V. bolus of phenylephrine or ephedrine on skin blood flow during spinal anesthesia

Effet d'un bolus intraveineux de phénylephrine ou d'éphedríne sur le flux sanguin cutané lors d'une anesthésie rachidienne Introduction : La phénylephrine et l'éphedrine sont des substances vaso-actives utilisées de routine pour corriger des épisodes d'hypotension artérielle induits par l'anesthésie intrarachidienne. L'influence de ces deux vasopresseurs sur le flux sanguin cutané (FSC) dans ce contexte n'a jusqu'à maintenant pas été décrite. Cette étude évalue l'effet d'une injection intraveineuse de 75 µg de phénylephrine ou de 7.5 mg d'éphedrine sur le FSC mesuré par Laser Doppler, dans les zones concernées parle bloc sympathiqué induit par l'anesthésie intrarachidienne (membres inférieurs) et dans les zones non concernées (membres supérieurs). Méthode :Après acceptation par le Comité d'Éthique, et obtention de leur accord écrit, 20 patients devant subir une intervention chirurgicale élective en décubitus dorsal sous anesthésie. intrarachidienne ont été inclus dans cette étude randomisée en double insu. Le FSC a été mesuré en continu par deux sondes fixées l'une à la cuisse (zone avec bloc sympathique) et l'autre sur l'avantbras (zone sans bloc sympathique). Les valeurs de FSC ont été enregistrées après l'anesthésie rachidienne (valeur contrôle), puis après l'injection i.v. dè phénylephrine (10 patients) ou d'éphedrine (10 patients) pour corriger une hypotension définie comme une chute de 20 mmHg de la pression artérielle systolique. Les variations de FSC exprimées en pourcentage de la valeur contrôle moyenne (+/- écart type) ont été analysées par le test t de Student. Résultats :Les données démographiques des patients et le niveau sensitif induit par l'anesthésie rachidienne sont similaires dans les deux groupes. Aux doses utilisées, seule l'éphedrine restaure la pression artérielle aux valeurs précédant l'anesthésie rachidienne. La phénylephrine augmente le FSC de l'avant-bras de 44% (+/- 79%) et de la cuisse de 34% (+/-24%), alors que l'éphedrine diminue le débit sanguin cutané de l'avant-bras de 16% (+/- 15%) et de la cuisse de 22% (+/-11%). Conclusion : L'injection intraveineuse de phénylephrine et d'éphedrine ont des effets opposés sur le flux sanguin cutané, et cette réponse n'est pas modifiée par le bloc sympathique.. Cette différence peut s'expliquer par la distribution des sous-types de récepteurs adrénergiques alpha et leur prédominance relative dans les veines et les artères de différents diamètres perfusant le tissu sous-cutané et la peau. L'éphedrine, èn raison de sa meilleure efficacité pour traiter les épisodes d'hypotension artérielle après anesthésie intrarachidienne devrait être préféré à la phénylephrine, leurs effets opposés sur le flux sanguin cutané n'étant pas pertinents en pratique clinique. SUMMARY Background: Phenylephrine or ephedrine is routinely used to correct hypotensive episodes fallowing spinal anaesthesia (SA). The influence of these two vasopressors on skin blood flow (SBF) has not yet been described. We have therefore evaluated the effects of an i.v. bolus of 75 µg phenylephrine or 7.5 mg of ephedrine on SBF measured by laser Doppler flowmetry during sympathetic blockade induced by SA. Methods: With Ethical Committee approval and written consent, 20 patients scheduled for elective procedures in supine position under SA were enrolled in this double-blind randomized study. SBF was measured continuously by two probes fixed at the thigh (area with sympathic blockade) and forearm level (area without sympathic blockade) respectively. SBF values were recorded after SA (control values) and then after a bolus administration of phenylephriné (n=10) or ephedrine (n=10) when systolic blood pressure decreased by 20 mmHg. Changes were expressed as percentage of control SBF values and analysed by Student's paired t-test. Results: Patient characteristics and dermatomal sensory levels were similar in both groups. Phenylephrine increases mean SBF at the forearm level by 44% (79%) [mean (SD)j and at the thigh by 34% (24%). Ephedrine decreases SBF at the forearm level by 16% (15%) and at the thigh by 22% (il%). Ephedrine bolus restores arterial blood pressure to pre-anaesthesia values, whereas phenylephrine does not. Conclusion: Administratión of phenylephrine and ephedrine has opposite effects on skin blood flow and sympathetic blockade does not modify this response. These findings could be explained by the distribution of the alpha-adrenoréceptor subtypes and their relative predominance among veins and arteries of different size perfusing the subcutaneous tissue and the skin. Ephedrine, due to its better efficacy to correct hypotensive episodes following SA, should be preferred, to phenylephrine, their opposite effects on SBF being not relevant for clinical practice.

Interaction between Telenomus remus and Trichogramma pretiosum in the management of Spodoptera spp.

Interaction betweeen Telenomus remus and Trichogramma pretiosum in the management of Spodoptera spp. The use of egg parasitoids is a promising strategy for Integrated Pest Management (IPM), but different species of parasitoids have greater or lesser control efficiency, depending on the pest species. Recently, not only Anticarsia gemmatalis and Pseudoplusia includens but also Spodoptera cosmioides and S. eridania have been among the key Lepidoptera larvae attacking soybeans. This study evaluated the combination of Telenomus remus and Trichogramma pretiosum for parasitism of eggs of the Spodoptera complex, for better control efficiency and broader spectrum of action among the key pests of soybeans. The experiment was carried out under controlled environmental conditions (25 ± 2ºC; 70 ± 10% RH; and 14 h photophase) in a completely randomized experimental design with seven treatments and 10 replicates with S. frugiperda, S. cosmioides and S. eridania eggs. Each replicate consisted of one egg mass of each Spodoptera species, with approximately 100 eggs offered to the parasitoids. The treatments were: 1) 10 females of T. pretiosum; 2) nine females of T. pretiosum and one female of T. remus; 3) eight females of T. pretiosum and two females of T. remus; 4) seven females of T. pretiosum and three females of T. remus; 5) six females of T. pretiosum and four females of T. remus; 6) five females of T. pretiosum and five females of T. remus, and 7) 10 females of T. remus. The parameter evaluated was the percentage of parasitized eggs. Results showed that treatments combining both parasitoid species with only 1 T. remus for each 9 T. pretiosum (10%) and only 2 T. remus for each 8 T. pretiosum (20%) were enough to significantly increase the parasitism observed on eggs of S. cosmioides and S. frugiperda, respectively. This association of T. pretiosum and T. remus in different proportions is very promising for biological control in IPM programs because it provides wide spectrum of control.

Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera, Tephritidae)

Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera, Tephritidae). Studies on Ceratitis capitata, a world fruit pest, can aid the implementation of control programs by determining the plants with higher vulnerability to attacks and plants able to sustain their population in areas of fly distribution. The objective of the present study was to evaluate the influence of eight tropical fruits on the following biological and behavioral parameters of C. capitata: emergence percentage, life cycle duration, adult size, egg production, longevity, fecundity, egg viability, and oviposition acceptance. The fruits tested were: acerola (Malpighia glabra L.), cashew (Anacardium occidentale L.), star fruit (Averrhoa carambola L.), guava (Psidium guajava L.), soursop (Annona muricata L.), yellow mombin (Spondias mombin L.), Malay apple (Syzygium malaccense L.), and umbu (Spondias tuberosa L.). The biological parameters were obtained by rearing the recently hatched larvae on each of the fruit kinds. Acceptance of fruits for oviposition experiment was assessed using no-choice tests, as couples were exposed to two pieces of the same fruit. The best performances were obtained with guava, soursop, and star fruit. Larvae reared on cashew and acerola fruits had regular performances. No adults emerged from yellow mombin, Malay apple, or umbu. Fruit species did not affect adult longevity, female fecundity, or egg viability. Guava, soursop, and acerola were preferred for oviposition, followed by star fruit, Malay apple, cashew, and yellow mombin. Oviposition did not occur on umbu. In general, fruits with better larval development were also more accepted for oviposition.

iLOGP: A Simple, Robust, and Efficient Description of n-Octanol/Water Partition Coefficient for Drug Design Using the GB/SA Approach.

The n-octanol/water partition coefficient (log Po/w) is a key physicochemical parameter for drug discovery, design, and development. Here, we present a physics-based approach that shows a strong linear correlation between the computed solvation free energy in implicit solvents and the experimental log Po/w on a cleansed data set of more than 17,500 molecules. After internal validation by five-fold cross-validation and data randomization, the predictive power of the most interesting multiple linear model, based on two GB/SA parameters solely, was tested on two different external sets of molecules. On the Martel druglike test set, the predictive power of the best model (N = 706, r = 0.64, MAE = 1.18, and RMSE = 1.40) is similar to six well-established empirical methods. On the 17-drug test set, our model outperformed all compared empirical methodologies (N = 17, r = 0.94, MAE = 0.38, and RMSE = 0.52). The physical basis of our original GB/SA approach together with its predictive capacity, computational efficiency (1 to 2 s per molecule), and tridimensional molecular graphics capability lay the foundations for a promising predictor, the implicit log P method (iLOGP), to complement the portfolio of drug design tools developed and provided by the SIB Swiss Institute of Bioinformatics.

Radiolabeled fragments of monoclonal antibodies against carcinoembryonic antigen for localization of human colon carcinoma grafted into nude mice.

Four monoclonal antibodies against carcinoembryonic antigen (CEA) have been selected from 32 hybrids that produce antibodies against this antigen, by the criteria of high affinity for CEA and low cross-reactivity with granulocyte glycoprotein(s). The specificity of tumor localization in vivo of the four MAb, and their F(ab')2 and Fab fragments was compared in nude mice bearing grafts of a serially transplanted, CEA-producing, human colon carcinoma. The distribution of radiolabeled MAb and their fragments after intravenous injection was analyzed by direct measurement of radioactivity in tumor and normal organs, as well as by whole-body scanning and by autoradiography of tumor sections. Paired labeling experiments, in which 131I-labeled antibody or fragments and 125I-labeled control IgG are injected simultaneously, were undertaken to determine the relative tumor uptakes of each labeled protein. The tumor antibody uptake divided by that of control IgG defines the specificity index of localization. Tumor antibody uptakes (as compared with the whole mouse), ranging between 7 and 15, and specificity indices ranging between 3.4 and 6.8, were obtained with the four intact MAb at day 4-5 after injection. With F(ab')2 fragments of the four MAb, at day 3, the tumor antibody uptakes ranged between 12 and 24 and the specificity indices between 5.3 and 8.2. With the Fab fragments prepared from the two most promising MAb, the antibody uptakes reached values of 34 and 82 at day 2-3 and the specificity indices were as high as 12 and 19. The scanning results paralleled those obtained by direct measurement of radioactivity. With intact MAb, tumor grafts of 0.5-1 g gave very contrasted positive scans 3 d after injection. Using MAb fragments, tumors of smaller size were detectable earlier. The best results were obtained with Fab fragments of MAb 35, which gave clear detections of tumors weighing only 0.1 g as early as 48 h after injection. Autoradiographs of tumor sections from mice injected with 125I-labeled MAb demonstrated that the radioactivity was localized in the tumor tissues and not in the stromal connective tissue of mouse origin. The highest radioactivity concentration was localized in areas known to contain CEA such as the pseudolumen of glands and the apical side of carcinoma cells. The penetration of radioactivity in the central part of tumor nodules and the pseudolumen appeared to be increased with the use of MAb fragments.

Effect of ganglion blockade with pentolinium on circulating neuropeptide Y levels in conscious rats.

The vasoconstrictor peptide, neuropeptide Y (NPY), is present in perivascular noradrenergic neurons of all mammals studied and may be important in the regulation of blood pressure. High plasma levels of NPY have been measured in the rat. To investigate partially the source and factors controlling the release of the circulating peptide, the effect of pentolinium tartrate administration has been studied in conscious rats. Pentolinium given as a bolus (5 mg/kg) followed by an infusion of a further 5 mg/kg/30 min produced a highly significant reduction in blood pressure of more than 40 mm Hg, when compared to either basal values or control animals treated with saline. Pentolinium treatment resulted in significantly lower plasma neuropeptide Y levels (31.0 +/- 6.7 fmol/ml) compared with those of control animals (78.6 +/- 8.2 fmol/ml). Circulating catecholamines were also significantly reduced in those animals receiving pentolinium. These results are compatible with circulating NPY arising from the sympathetic nervous system, with release being controlled by the mechanisms already established for catecholamines.

The History of the Establishment of the Division of Child Welfare of the Social Welfare Department of the State of Iowa, 1938

History of Child Welfare Legislation in the State of Iowa 1838-1898; Establishment of the Iowa State board of Control in 1898 and its influence on Child Welfare Legislation until 1925; Immediate background, organizing and the administration functions of the Child Welfare Division of the Social Welfare Department of the State of Iowa. NOTE: This document has pagination errors.

The costs of crossing paths and switching tasks between audition and vision.

Switching from one functional or cognitive operation to another is thought to rely on executive/control processes. The efficacy of these processes may depend on the extent of overlap between neural circuitry mediating the different tasks; more effective task preparation (and by extension smaller switch costs) is achieved when this overlap is small. We investigated the performance costs associated with switching tasks and/or switching sensory modalities. Participants discriminated either the identity or spatial location of objects that were presented either visually or acoustically. Switch costs between tasks were significantly smaller when the sensory modality of the task switched versus when it repeated. This was the case irrespective of whether the pre-trial cue informed participants only of the upcoming task, but not sensory modality (Experiment 1) or whether the pre-trial cue was informative about both the upcoming task and sensory modality (Experiment 2). In addition, in both experiments switch costs between the senses were positively correlated when the sensory modality of the task repeated across trials and not when it switched. The collective evidence supports the independence of control processes mediating task switching and modality switching and also the hypothesis that switch costs reflect competitive interference between neural circuits.

Atrial assist device, a new alternative to lifelong anticoagulation?

OBJECTIVE: Atrial fibrillation is a very common heart arrhythmia, associated with a five-fold increase in the risk of embolic strokes. Treatment strategies encompass palliative drugs or surgical procedures all of which can restore sinus rhythm. Unfortunately, atria often fail to recover their mechanical function and patients therefore require lifelong anticoagulation therapy. A motorless volume displacing device (Atripump) based on artificial muscle technology, positioned on the external surface of atrium could avoid the need of oral anticoagulation and its haemorrhagic complications. An animal study was conducted in order to assess the haemodynamic effects that such a pump could provide. METHODS: Atripump is a dome-shape siliconecoated nitinol actuator sewn on the external surface of the atrium. It is driven by a pacemaker-like control unit. Five non-anticoagulated sheep were selected for this experiment. The right atrium was surgically exposed, the device sutured and connected. Haemodynamic parameters and intracardiac ultrasound (ICUS) data were recorded in each animal and under three conditions; baseline; atrial fibrillation (AF); atripump assisted AF (aaAF). RESULTS: In two animals, after 20 min of AF, small thrombi appeared in the right atrial appendix and were washed out once the pump was turned on. Assistance also enhanced atrial ejection fraction. 31% baseline; 5% during AF; 20% under aaAF. Right atrial systolic surfaces (cm2) were; 5.2 +/- 0.3 baseline; 6.2 +/- 0.1 AF; 5.4 +/- 0.3 aaAF. CONCLUSION: This compact and reliable pump seems to restore the atrial "kick" and prevents embolic events. It could avoid long-term anticoagulation therapy and open new hopes in the care of end-stage heart failure.

Protective effect of divalent cations against aluminum toxicity in soybean

A large proportion of soybean fields in Brazil are currently cultivated in the Cerrado region, where the area planted with this crop is growing considerably every year. Soybean cultivation in acid soils is also increasing worldwide. Since the levels of toxic aluminum (Al) in these acid soils is usually high it is important to understand how cations can reduce Al rhizotoxicity in soybean. In the present study we evaluated the ameliorative effect of nine divalent cations (Ca, Mg, Mn, Sr, Sn, Cu, Zn, Co and Ba) in solution culture on Al rhizotoxicity in soybean. The growth benefit of Ca and Mg to plants in an acid Inceptisol was also evaluated. In this experiment soil exchangeable Ca:Mg ratios were adjusted to reach 10 and 60 % base saturation, controlled by different amounts of CaCl2 or MgCl2 (at proportions from 100:0 up to 0:100), without altering the soil pH level. The low (10 %) and adequate (60 %) base saturation were used to examine how plant roots respond to Al at distinct (Ca + Mg)/Al ratios, as if they were growing in soils with distinct acidity levels. Negative and positive control treatments consisted of absence (under native soil or undisturbed conditions) or presence of lime (CaCO3) to reach 10 and 60 % base saturation, respectively. It was observed that in the absence of Aluminum, Cu, Zn, Co and Sn were toxic even at a low concentration (25 µmol L-1), while the effect of Mn, Ba, Sr and Mg was positive or absent on soybean root elongation when used in concentrations up to 100 µmol L-1. At a level of 10 µmol L-1 Al, root growth was only reverted to the level of control plants by the Mg treatment. Higher Tin doses led to a small alleviation of Al rhizotoxicity, while the other cations reduced root growth or had no effect. This is an indication that the Mg effect is ion-specific and not associated to an electrostatic protection mechanism only, since all ions were divalent and used at low concentrations. An increased exchangeable Ca:Mg ratio (at constant soil pH) in the acid soil almost doubled the soybean shoot and root dry matter even though treatments did not modify soil pH and exchangeable Al3+. This indicates a more efficient alleviation of Al toxicity by Mg2+ than by Ca2+. The reason for the positive response to Mg2+ was not the supply of a deficient nutrient because CaCO3 increased soybean growth by increasing soil pH without inducing Mg2+ deficiency. Both in hydroponics and acid soil, the reduction in Al toxicity was accompanied by a lower Al accumulation in plant tissue, suggesting a competitive cation absorption and/or exclusion of Al from plant tissue stimulated by an Mg-induced physiological mechanism.

Clinical usefulness of therapeutic concentration monitoring for imatinib dosage individualization: Results from the randomized controlled I-COME Trial

Introduction: Imatinib trough plasma concentrations (Cmin) have been correlated with treatment response in chronic myeloid leukemia (CML) patients. The use of Cmin monitoring for optimizing imatinib dosage (therapeutic drug monitoring [TDM]) is therefore proposed for patients with unsatisfying response or tolerance ("rescue TDM"). A cycle of "routine TDM" for dosage individualization could also be beneficial to prevent unfavorable events, yet its clinical usefulness has not been evaluated. We aimed to assess prospectively whether a "routine TDM" intervention targeting imatinib Cmin of 1000 ng/mL (tolerance, 750-1500 ng/mL) could improve efficacy, tolerance, and persistence on treatment compared with "rescue TDM" use only. Patients (or Materials) and Methods: The Swiss Imatinib COncentration Monitoring Evaluation (I-COME) study was a multicenter randomized controlled trial (ISRCTN31181395). Adult patients in chronic or accelerated phase CML receiving imatinib ≤5 years were eligible. Patients were randomly (1:1) allocated to receive "routine TDM" intervention or to serve as controls with access only to "rescue TDM". All had 1-year follow-up. The primary endpoint was a combined efficacy-safety outcome (failure- and toxicity-free survival without imatinib discontinuation), analyzed in intention-to-treat. Results: Among 56 CML recruited patients, 55 had their molecular and cytogenetic response measured. 14/27 of patients receiving "routine TDM" (52% [33%-71%]) remained event-free versus 16/28 of control patients with "rescue TDM" only (57% [39%-75%]; P=0.69). In the "routine TDM" group, dosage recommendations were adopted entirely in 50% of patients (median Cmin at study end, 895 ng/mL; CV = 33%). These patients had fewer unfavorable events (28% [5%-52%]) compared with patients not receiving the advised dosage (77% [54%-99%]; P = 0.03; median Cmin at study end, 648 ng/mL; CV = 38%). Conclusion: This first prospective target concentration intervention trial could not formally demonstrate a benefit of "routine TDM" of imatinib, especially due to a small patient number and limited prescriber's adherence to dosage recommendations. Nevertheless, the patients receiving the advised dosage more often met target concentrations and the combined outcome (efficacy, tolerance, and persistence). A cycle of routine TDM could thus be favorable, at least in patients eligible for dosage adjustment. Its usefulness should, however, be further confirmed in larger trials.

Functional role of RXRs and PPARgamma in mature adipocytes.

The peroxisome proliferator-activated receptor gamma (PPARgamma) is abundantly expressed in adipocytes, and plays an important role in adipocyte differentiation and fat accretion. It is a heterodimeric partner of the retinoid X receptors alpha, beta and gamma, which are also expressed in the adipose tissue. As lethality of PPARgamma(-/-) and RXRalpha(-/-) mouse fetuses precluded the analysis of PPARgamma and RXRalpha functions in mature adipocytes, we generated RXRalpha(ad-/-) and PPARgamma(ad-/-) mice, in which RXRalpha and PPARgamma are selectively ablated in adult adipocytes, respectively. Even though the adiposity of RXRalpha(ad-/-) mice is similar to that of control mice when fed a regular diet, they are resistant to chemically and dietary-induced obesity. However, mature adipocytes lacking either both RXRalpha and RXRgamma or PPARgamma die, and are replaced by newly formed adipocytes. Thus, in adipocytes, RXRalpha is essential for lipogenesis, but RXRgamma can functionally replace RXRalpha for the adipocyte vital functions exerted by PPARgamma/RXR heterodimers.

Detrital zircon and micropalaeontological ages as new constraints for the lowermost tectonic unit (Talea Ori unit) of Crete, Greece

The Talea Ori unit is the lowermost known tectonic unit of Crete and the most external part of the Hellenides. Its stratigraphy ranges from Late Carboniferous to Oligocene and outcrops of the lower part are only known in the Talea Ori mountains (central Crete). In this area, a black sandstone at the base of the Galinos Beds, thought to be the oldest formation, contains zircons which were dated using the single grain evaporation method. The majority of these grains yielded Late Carboniferous ages (Variscan), while a small group yielded Early Proterozoic ages. The age distribution of these zircons suggests that, at the Carboniferous-Permian boundary, not much of the older North Gondwanan basement was exposed and that a river system carried detrital material from the Variscan belt towards the forming Neotethyan rift. Additionally, higher up in the stratigraphy benthic foraminifers (miliolids) were found in clasts from a conglomerate which was so far thought to be of Early Triassic age [Epting, M., Kudrass, H.-R., Leppig, U., Schaffer, A., 1972. Geologie der Talea Ori/Kreta. N. Jb. Geol. Palaont. Abh. 141, 259-285.]. These miliolids belong to the species Hoyenella inconstans [Michalik, J., Jendrejakova, O., Borza, K., 1979. Some new foraminifera species of the Fatra-Formation (Uppermost Triassic) in the West Carpathians. Geol. Carpath. 30 (1), 61-91.], thus attributing a Late Triassic (Carnian-Norian?) maximal age to this conglomerate. The carbonate platform from which the miliolids-bearing clasts come is not known. The presence to the north of a continuous hemipelagic record from the Carboniferous to the Triassic (Phyllite-Quartzite and Tripali units), attributed to the Palaeotethys realm, allows the Talea Ori unit and its lateral equivalents (the Ionian zone) to be assigned to the westward continuation of the Cimmerian block and therefore to the northern margin of the East Mediterranean Neotethys ocean. (c) 2006 Elsevier B.V. All rights reserved.

Temperature-induced resonances and Landau damping of collective modes in Bose-Einstein condensed gases in spherical traps

Interaction between collective monopole oscillations of a trapped Bose-Einstein condensate and thermal excitations is investigated by means of perturbation theory. We assume spherical symmetry to calculate the matrix elements by solving the linearized Gross-Pitaevskii equations. We use them to study the resonances of the condensate induced by temperature when an external perturbation of the trapping frequency is applied and to calculate the Landau damping of the oscillations.