Contribution to the geology of Thailand and implications for the geodynamic evolution of Southeast Asia

Abstract The purpose of this study is to unravel the geodynamic evolution of Thailand and, from that, to extend the interpretation to the rest of Southeast Asia. The methodology was based in a first time on fieldwork in Northern Thailand and Southernmost Myanmar, using a multidisciplinary approach, and then on the compilation and re-interpretation, in a plate tectonics point of view, of existing data about the whole Southeast Asia. The main results concern the Nan-Uttaradit suture, the Chiang Mai Volcanic Belt and the proposition of a new location for the Palaeotethys suture. This led to the establishment of a new plate tectonic model for the geodynamic evolution of Southeast Asia, implying the existence new terranes (Orang Laut and the redefinition of Shan-Thai) and the role of the Palaeopacific Ocean in the tectonic development of the area. The model proposed here considers the Palaeotethys suture as located along the Tertiary Mae Yuam Fault, which represents the divide between the Cimmerian Sibumasu terrane and the Indochina-derived Shan-Thai block. The term Shan-Thai, previously used to define the Cimmerian area (when the Palaeotethys suture was thought to represented by the Nan-Uttaradit suture), was redefined here by keeping its geographical location within the Shan States of Myanmar and Central-Northern Thailand, but attributing it an East Asian Origin. Its detachment from Indochina was the result of the Early Permian opening of the Nan basin. The Nan basin closed during the Middle Triassic, before the deposition of Carnian-Norian molasse. The modalities of the closure of the basin imply a first phase of Middle Permian obduction, followed by final eastwards subduction. The Chiang Mai Volcanic Belt consists of scattered basaltic rocks erupted at least during the Viséan in an extensional continental intraplate setting, on the Shan-Thai part of the Indochina block. The Viséan age was established by the dating of limestone stratigraphically overlying the basalts. In several localities of the East Asian Continent, coeval extensional features occur, possibly implying one or more Early Carboniferous extensional events at a regional scale. These events occurred either due to the presence of a mantle plume or to the roll-back of the Palaeopacific Ocean, subducting beneath Indochina and South China, or both. The Palaeopacific Ocean is responsible, during the Early Permian, for the opening of the Song Ma and Poko back-arcs (Vietnam) with the consequent detachment of the Orang Laut Terranes (Eastern Vietnam, West Sumatra, Kalimantan, Palawan, Taiwan). The Late Triassic/Early Jurassic closure of the Eastern Palaeotethys is considered as having taken place by subduction beneath its southern margin (Gondwana), due to the absence of Late Palaeozoic arc magmatism on its northern (Indochinese) margin and the presence of volcanism on the Cimmerian blocks (Mergui, Lhasa). Résumé Le but de cette étude est d'éclaircir l'évolution géodynamique de la Thaïlande et, à partir de cela, d'étendre l'interprétation au reste de l'Asie du Sud-Est. La méthodologie utilisée est basée dans un premier temps sur du travail de terrain en Thaïlande du nord et dans l'extrême sud du Myanmar, en se basant sur une approche pluridisciplinaire. Dans un deuxième temps, la compilation et la réinterprétation de données préexistantes sur l'Asie du Sud-est la été faite, dans une optique basée sur la tectonique des plaques. Les principaux résultats de ce travail concernent la suture de Nan-Uttaradit, la « Chiang Mai Volcanic Belt» et la proposition d'une nouvelle localité pour la suture de la Paléotethys. Ceci a conduit à l'établissement d'un nouveau modèle pour l'évolution géodynamique de l'Asie du Sud-est, impliquant l'existence de nouveaux terranes (Orang Laut et Shan-Thai redéfini) et le rôle joué par le Paléopacifique dans le développement tectonique de la région. Le modèle présenté ici considère que la suture de la Paléotethys est située le long de la faille Tertiaire de Mae Yuam, qui représente la séparation entre le terrain Cimmérien de Sibumasu et le bloc de Shan-Thai, d'origine Indochinoise. Le terme Shan-Thai, anciennement utilise pour définir le bloc Cimmérien (quand la suture de la Paléotethys était considérée être représentée par la suture de Nan-Uttaradit), a été redéfini ici en maintenant sa localisation géographique dans les états Shan du Myanmar et la Thaïlande nord-centrale, mais en lui attribuant une origine Est Asiatique. Son détachement de l'Indochine est le résultat de l'ouverture du basin de Nan au Permien Inférieur. Le basin de Nan s'est fermé pendant le Trias Moyen, avant le dépôt de molasse Carnienne-Norienne. Les modalités de fermeture du basin invoquent une première phase d'obduction au Permien Moyen, suivie par une subduction finale vers l'est. La "Chiang Mai Volcanic Belt" consiste en des basaltes éparpillés qui ont mis en place au moins pendant le Viséen dans un contexte extensif intraplaque continental sur la partie de l'Indochine correspondant au bloc de Shan-Thai. L'âge Viséen a été établi sur la base de la datation de calcaires qui surmontent stratigraphiquement les basaltes. Dans plusieurs localités du continent Est Asiatique, des preuves d'extension plus ou moins contemporaines ont été retrouvées, ce qui implique l'existence d'une ou plusieurs phases d'extension au Carbonifère Inférieur a une échelle régionale. Ces événements sont attribués soit à la présence d'un plume mantellique, ou au rollback du Paléopacifique, qui subductait sous l'Indochine et la Chine Sud, soit les deux. Pendant le Permien inférieur, le Paléopacifique est responsable pour l'ouverture des basins d'arrière arc de Song Ma et Poko (Vietnam), induisant le détachement des Orang Laut Terranes (Est Vietnam, Ouest Sumatra, Kalimantan, Palawan, Taiwan). La fermeture de la Paléotethys Orientale au Trias Supérieur/Jurassique Inférieur est considérée avoir eu lieu par subduction sous sa marge méridionale (Gondwana), à cause de l'absence de magmatisme d'arc sur sa marge nord (Indochinoise) et de la présence de volcanisme sur les blocs Cimmériens de Lhassa et Sibumasu (Mergui). Résumé large public L'histoire géologique de l'Asie du Sud-est depuis environ 430 millions d'années a été déterminée par les collisions successives de plusieurs continents les uns avec les autres. Il y a environ 430 millions d'années, au Silurien, un grand continent appelé Gondwana, a commencé à se «déchirer» sous l'effet des contraintes tectoniques qui le tiraient. Cette extension a provoqué la rupture du continent et l'ouverture d'un grand océan, appelé Paléotethys, éloignant les deux parties désormais séparées. C'est ainsi que le continent Est Asiatique, composé d'une partie de la Chine actuelle, de la Thaïlande, du Myanmar, de Sumatra, du Vietnam et de Bornéo a été entraîné avec le bord (marge) nord de la Paléotethys, qui s'ouvrait petit à petit. Durant le Carbonifère Supérieur, il y a environ 300 millions d'années, le sud du Gondwana subissait une glaciation, comme en témoigne le dépôt de sédiments glaciaires dans les couches de cet âge. Au même moment le continent Est Asiatique se trouvait à des latitudes tropicales ou équatoriales, ce qui permettait le dépôt de calcaires contenant différents fossiles de foraminifères d'eau chaude et de coraux. Durant le Permien Inférieur, il y a environ 295 millions d'années, la Paléotethys Orientale, qui était un relativement vieil océan avec une croûte froide et lourde, se refermait. La croûte océanique a commencé à s'enfoncer, au sud, sous le Gondwana. C'est ce que l'on appelle la subduction. Ainsi, le Gondwana s'est retrouvé en position de plaque supérieure, par rapport à la Paléotethys qui, elle, était en plaque inférieure. La plaque inférieure en subductant a commencé à reculer. Comme elle ne pouvait pas se désolidariser de la plaque supérieure, en reculant elle l'a tirée. C'est le phénomène du «roll-back ». Cette traction a eu pour effet de déchirer une nouvelle fois le Gondwana, ce qui a résulté en la création d'un nouvel Océan, la Neotethys. Cet Océan en s'ouvrant a déplacé une longue bande continentale que l'on appelle les blocs Cimmériens. La Paléotethys était donc en train de se fermer, la Neotethys de s'ouvrir, et entre deux les blocs Cimmériens se rapprochaient du Continent Est Asiatique. Pendant ce temps, le continent Est Asiatique était aussi soumis à des tensions tectoniques. L'Océan Paléopacifique, à l'est de celui-ci, était aussi en train de subducter. Cette subduction, par roll-back, a déchiré le continent en détachant une ligne de microcontinents appelés ici « Orang Laut Terranes », séparés du continent par deux océans d'arrière arc : Song Ma et Poko. Ceux-ci sont composés de Taiwan, Palawan, Bornéo ouest, Vietnam oriental, et la partie occidentale de Sumatra. Un autre Océan s'est ouvert pratiquement au même moment dans le continent Est Asiatique : l'Océan de Nan qui, en s'ouvrant, a détaché un microcontinent appelé Shan-Thai. La fermeture de l'Océan de Nan, il y a environ 230 millions d'années a resolidarisé Shan-Thai et le continent Est Asiatique et la trace de cet événement est aujourd'hui enregistrée dans la suture (la cicatrice de l'Océan) de Nan-Uttaradit. La cause de l'ouverture de l'Océan de Nan peut soit être due à la subduction du Paléopacifique, soit aux fait que la subduction de la Paléotethys tirait le continent Est Asiatique par le phénomène du « slab-pull », soit aux deux. La subduction du Paléopacifique avait déjà crée de l'extension dans le continent Est Asiatique durant le Carbonifère Inférieur (il y a environ 340-350 millions d'années) en créant des bassins et du volcanisme, aujourd'hui enregistré en différents endroits du continent, dont la ceinture volcanique de Chiang Mai, étudiée ici. A la fin du Trias, la Paléotethys se refermait complètement, et le bloc Cimmérien de Sibumasu entrait en collision avec le continent Est Asiatique. Comme c'est souvent le cas avec les grands océans, il n'y a pas de suture proprement dite, avec des fragments de croûte océanique, pour témoigner de cet évènement. Celui-ci est visible grâce à la différence entre les sédiments du Carbonifère Supérieur et du Permieñ Inférieur de chaque domaine : dans le domaine Cimmérien ils sont de type glaciaire alors que dans le continent Est Asiatique ils témoignent d'un climat tropical. Les océans de Song Ma et Poko se sont aussi refermés au Trias, mais eux ont laissé des sutures visibles

Physa cubensis Pfeiffer, 1839 (Pulmonata: Physidae)

A description of Physa cubensis Pfeiffer, 1839, based on 15 speciments collected in Havana, Cuba, is presented. The shell, measuring 9.0 x 4,8mm to 12.3 x 6.4mm, is ovate-oblong, thin, diaphanous, horncolored, shining. Spire elevated, broadly conical; protoconch distinct, roundish, reddish-brown. About five moderately shouldered, roundly convex whorls, penultimate whorl expanded; spiral striation subobsolete; growth line faint on the intermediate whorls, clearly visible on the body whorl, crowded here and there. Suture well impressed. Aperture elongated 2.05 - 2.67 (mean 2.27) times as long as the remaining length of the shell, narrow obovulate-lunate; upper half acute-angled, lower half oval, narrowly rounded at the base; outer lip sharp, inner lip completely closing the umbilical region; a thick callus on the parietal wall; columellar plait well marked. Ratios: shell width/shell length - 0.52-0.61 (mean 0.55); spire length/shell length = 0.27 - 0.33 (mean 0.31); aperture length/shell length = 0.67 - 0.73 (mean 0.69). Oral lappets laterally mucronate; foot spatulate with acuminate tail. Mantle relection with 6 - 8 short triangular dentations in the right lobe (columellar side) and 4 - 6 in the left lobe (near the pneumostome). Renal tube tightly folded into a zigzag course. Ovotestis, ovispermiduct, seminal vesicle, oviduct, nidamental gland, uterus and vagina as in Physa marmorata (see Paraense, 1986, Mem. Inst. Oswaldo Cruz, 81: 459-469). Spermathecal body egg-shaped or pear-shaped; spermathecal ducta uniformly narrow with expanded base, a little longer than the body. Spermiduct, prostate and vas deferens as in P. marmorata (Paraense, loc. cit.). Penis wide proximally, narrowing gradually apicad; penial canal with subterminal outlet. Penial sheath following the width of the penis and ending up by a bulbous expansion somewhat narrower than the proximal portion. Penaial sheath/prepuce ration = 1,25 - 1,83 (mean 1.49). Prepuce much wider than the bulb of the penial shealth, moderately shouldered owing to the intromission of the bulb, and with a large gland in one side of its proximal half occupating about a third of its length. Extrinsic muscles of the penial complex as in P. marmorata. Jaw a simple obtusely V-shaped plate. Radula to be described separetely.

Reproducibility of free-breathing cardiovascular magnetic resonance coronary angiography.

OBJECTIVE: Contemporary free-breathing non contrast enhanced cardiovascular magnetic resonance angiography (CMRA) was qualitatively and quantitatively evaluated to ascertain the reproducibility of the method for coronary artery luminal dimension measurements. SUBJECTS AND METHODS: Twenty-two healthy volunteers (mean age 32 +/- 7 years, 12 males) without coronary artery disease were imaged at 2 centers (1 each in Europe and North America) using navigator-gated and corrected SSFP CMRA on a commercial whole body 1.5T System. Repeat images of right (RCA, n = 21), left anterior descending (LAD, n = 14) and left circumflex (LCX, n = 14) coronary arteries were obtained in separate sessions using identical scan protocol and imaging parameters. True visible vessel length, signal-to-noise (SNR), contrast-to-noise ratios (CNR) and the average luminal diameter over the first 4 cm of the vessel were measured. Intra-observer, inter-observer and inter-scan reproducibility of coronary artery luminal diameter were determined using Pearson's correlation, Bland-Altman analysis and intraclass correlation coefficients (ICC). RESULTS: CNR, SNR and the mean length of the RCA, LAD and LCX imaged for original and repeat scans were not significantly different (all p > 0.30). There was a high degree of intra-observer, inter-observer and inter-scan agreements for RCA, LAD and LCX luminal diameter respectively on Bland-Altman and ICC analysis (ICC's for RCA: 0.98. 0.98 and 0.86; LAD: 0.89, 0.89 and 0.63; LCX: 0.95, 0.94 and 0.79). CONCLUSION: In a 2-center study, we demonstrate that free-breathing 3D SSFP CMRA can visualize long continuous segments of coronary vessels with highly reproducible measurements of luminal diameter.

Waddlia chondrophila Infects and Multiplies in Ovine Trophoblast Cells Stimulating an Inflammatory Immune Response.

BACKGROUND: Waddlia chondrophila (W. chondrophila) is an emerging abortifacient organism which has been identified in the placentae of humans and cattle. The organism is a member of the order Chlamydiales, and shares many similarities at the genome level and in growth studies with other well-characterised zoonotic chlamydial abortifacients, such as Chlamydia abortus (C. abortus). This study investigates the growth of the organism and its effects upon pro-inflammatory cytokine expression in a ruminant placental cell line which we have previously utilised in a model of C. abortus pathogenicity. METHODOLOGY/PRINCIPAL FINDINGS: Using qPCR, fluorescent immunocytochemistry and electron microscopy, we characterised the infection and growth of W. chondrophila within the ovine trophoblast AH-1 cell line. Inclusions were visible from 6 h post-infection (p.i.) and exponential growth of the organism could be observed over a 60 h time-course, with significant levels of host cell lysis being observed only after 36 h p.i. Expression of CXCL8, TNF-α, IL-1α and IL-1β were determined 24 h p.i. A statistically significant response in the expression of CXCL8, TNF-α and IL-1β could be observed following active infection with W. chondrophila. However a significant increase in IL-1β expression was also observed following the exposure of cells to UV-killed organisms, indicating the stimulation of multiple innate recognition pathways. CONCLUSIONS/SIGNIFICANCE: W. chondrophila infects and grows in the ruminant trophoblast AH-1 cell line exhibiting a complete chlamydial replicative cycle. Infection of the trophoblasts resulted in the expression of pro-inflammatory cytokines in a dose-dependent manner similar to that observed with C. abortus in previous studies, suggesting similarities in the pathogenesis of infection between the two organisms.

Thrombolysis in ischemic stroke without arterial occlusion at presentation.

BACKGROUND AND PURPOSE: None of the randomized trials of intravenous tissue-type plasminogen activator reported vascular imaging acquired before thrombolysis. Efficacy of tissue-type plasminogen activator in stroke without arterial occlusion on vascular imaging remains unknown and speculative. METHODS: We performed a retrospective, multicenter study to collect data of patients who presented to participating centers during a 5-year period with ischemic stroke diagnosed by clinical examination and MRI and with imaging evidence of no vascular occlusion. These patients were divided into 2 groups: those who received thrombolytic therapy and those who did not. Primary outcome measure of the study was excellent clinical outcome defined as modified Rankin Scale of 0 to 1 at 90 days from stroke onset. Secondary outcome measures were good clinical outcome (modified Rankin Scale, 0-2) and perfect outcome (modified Rankin Scale, 0). Safety outcome measures were incidence of symptomatic intracerebral hemorrhage and poor outcome (modified Rankin Scale, 4-6). RESULTS: A total of 256 patients met study criteria, 103 with thrombolysis and 153 without. Logistic regression analysis showed that patients who received thrombolysis had more frequent excellent outcomes with odds ratio of 3.79 (P<0.01). Symptomatic intracerebral hemorrhage was more frequent in thrombolysis group (4.9 versus 0.7%; P=0.04). Thrombolysis led to more frequent excellent outcome in nonlacunar group with odds ratio 4.90 (P<0.01) and more frequent perfect outcome in lacunar group with odds ratio 8.25 (P<0.01). CONCLUSIONS: This study provides crucial data that patients with ischemic stroke who do not have visible arterial occlusion at presentation may benefit from thrombolysis.

Periodontitis and gingivitis in inflammatory bowel disease: a case-control study.

BACKGROUND: The oral cavity is frequently affected in patients with inflammatory bowel disease (IBD), especially in patients with Crohn's disease (CD). Periodontitis is thought to influence systemic autoimmune or inflammatory diseases. We aimed to analyze the relationship of periodontitis and gingivitis markers with specific disease characteristics in patients with IBD and to compare these data with healthy controls. METHODS: In a prospective 8-month study, systematic oral examinations were performed in 113 patients with IBD, including 69 patients with CD and 44 patients with ulcerative colitis. For all patients, a structured personal history was taken. One hundred thirteen healthy volunteers served as a control group. Oral examination focussed on established oral health markers for periodontitis (bleeding on probing, loss of attachment, and periodontal pocket depth) and gingivitis (papilla bleeding index). Additionally, visible oral lesions were documented. RESULTS: Both gingivitis and periodontitis markers were higher in patients with IBD than in healthy control. In univariate analysis and logistic regression analysis, perianal disease was a risk factor for periodontitis. Nonsmoking decreased the risk of having periodontitis. No clear association was found between clinical activity and periodontitis in IBD. In only the CD subgroup, high clinical activity (Harvey-Bradshaw index > 10) was associated with 1 periodontitis marker, the loss of attachment at sites of maximal periodontal pocket depth. Oral lesions besides periodontitis and gingivitis were not common, but nevertheless observed in about 10% of patients with IBD. CONCLUSIONS: IBD, and especially perianal disease in CD, is associated with periodontitis. Optimal therapeutic strategies should probably focus on treating both local oral and systemic inflammation.

A behavioral study of alpha-1b adrenergic receptor knockout mice: increased reaction to novelty and selectively reduced learning capacities.

Knockout mice lacking the alpha-1b adrenergic receptor were tested in behavioral experiments. Reaction to novelty was first assessed in a simple test in which the time taken by the knockout mice and their littermate controls to enter a second compartment was compared. Then the mice were tested in an open field to which unknown objects were subsequently added. Special novelty was introduced by moving one of the familiar objects to another location in the open field. Spatial behavior and memory were further studied in a homing board test, and in the water maze. The alpha-1b knockout mice showed an enhanced reactivity to new situations. They were faster to enter the new environment, covered longer paths in the open field, and spent more time exploring the new objects. They reacted like controls to modification inducing spatial novelty. In the homing board test, both the knockout mice and the control mice seemed to use a combination of distant visual and proximal olfactory cues, showing place preference only if the two types of cues were redundant. In the water maze the alpha-1b knockout mice were unable to learn the task, which was confirmed in a probe trial without platform. They were perfectly able, however, to escape in a visible platform procedure. These results confirm previous findings showing that the noradrenergic pathway is important for the modulation of behaviors such as reaction to novelty and exploration, and suggest that this is mediated, at least partly, through the alpha-1b adrenergic receptors. The lack of alpha-1b adrenergic receptors in spatial orientation does not seem important in cue-rich tasks but may interfere with orientation in situations providing distant cues only.

Extensor carpi ulnaris (ECU) subsheath: Normal MRI appearance and findings in athletic injuries : 40

Purpose: First, to report ECU subsheath's normal MRI appearance and the findings in athletic injuries. Second, to determine the best MRI sequence for diagnosis. Methods and materials: Sixteen patients (13 males, 3 females, mean age 30.3 years) with ECU subsheath's athletic injuries sustained between January 2003 and June 2009 were retrospectively reviewed. Wrist MRI studies were performed on 1.5-T units and consisted of at least transverse T1 and STIR sequences in pronation, and FS Gd T1 in pronation and supination. Two radiologists assessed the following items, in consensus: injury type (A to C according to Inoue), ECU tendon stability, and associated lesions (ulnar head oedema, extensor retinaculum injury, ECU tendinosis and tenosynovitis). Then, each reader independently rated the sequences' diagnostic value: 0 = questionable, 1 = suggestive, 2 = certain. Follow-up studies were present in 8 patients. ECU subsheath's normal visibility (medial, central and lateral parts) was retrospectively evaluated in 30 consecutive control MRI studies. Results: FS Gd T1 sequences in supination (1.63) and pronation (1.59) were the most valuable for diagnosis, compared to STIR (1.22) and T1 (1). The study group included 9 type A, 1 type B and 6 type C injuries. There were trends towards diminution in pouches' size, signal intensity and enhancement in follow-up studies, along with tendon stabilization within the ulnar groove. In control studies, ECU subsheath's visibility in medial, central and lateral parts were noted in 66.7-80%, 63.3-80% and 30-50% respectively. Conclusion: ECU subsheath's athletic injuries are visible on 1.5-T MRI studies. FS Gd T1 sequences in supination and pronation are the most valuable.

The effect of the N-methyl-D-aspartate receptor antagonist dextromethorphan on perioperative brain injury in children undergoing cardiac surgery with cardiopulmonary bypass: results of a pilot study.

Experimental evidence indicates a role of the N-methyl-D-aspartate receptor in the pathogenesis of brain injury occurring during cardiac surgery with cardiopulmonary bypass (CPB). Dextromethorphan is a noncompetitive antagonist of this receptor with a favorable safety profile. Thirteen children age 3-36 months undergoing cardiac surgery with expected CPB of 60 minutes or more were randomly assigned to treatment with dextromethorphan (36-38 mg/kg/day) or placebo administered by naso-gastric tube. Dextromethorphan was absorbed well and reached putative therapeutic levels in blood and cerebrospinal fluid. Adverse effects were not observed. Mild hemiparesis developed after operation in one child of each group, and severe encephalopathy in one of the placebo group. Sharp waves were recorded in postoperative continuous electroencephalography in all placebo (n = 7) but only in 2/6 dextromethorphan treated children (p = 0.02). Pre- and postoperative cranial magnetic resonance imaging (MRI) revealed less pronounced ventricular enlargement in the dextromethorphan group (not significant). An increase of periventricular white matter lesions was visible in two placebo-treated children only. No elevations of cerebrospinal fluid enzymes were observed in either group. Although children with dextromethorphan showed less abnormalities in electroencephalography and MRI, dissimilarities of the treatment groups by chance diminished conclusions to possible protective effects of dextromethorphan at this time.

(Don’t) Make My Vote Count

Proponents of proportional electoral rules often argue that majority rule depresses turnout and may lower welfare due to the 'tyranny of the majority' problem. The present paper studies the impact of electoral rules on turnout and social welfare. We analyze a model of instrumental voting where citizens have private information over their individual cost of voting and over the alternative they prefer. The electoral rule used to select the winning alternative is a combination of majority rule and proportional rule. Results show that the above arguments against majority rule do not hold in this set up. Social welfare and turnout increase with the weight that the electoral rule gives to majority rule when the electorate is expected to be split, and they are independent of the electoral rule employed when the expected size of the minority group tends to zero. However, more proportional rules can increase turnout within the minority group. This effect is stronger the smaller the minority group. We then conclude that majority rule fosters overall turnout and increases social welfare, whereas proportional rule fosters the participation of minorities.

On the morphology of Laevapex vazi n. sp. from Brazil (Mollusca: Pulmonata: Basommatophora: Ancylidae)

A description of Laevapex vazi n. sp. based on 8 specimens collectec in Ourinhos, state of São Paulo, is presented. Shell thin, diaphanous, with a light brown periostracum and moderately elliptical opening. Apex not pointed, smooth, situated on the right posterior region of the shell, inclined to the right often reaching the edge of the shell or extending beyond it. Concentric lines clearly visible; radial striation not visible or when perceptible very thin, here and there. Ratios: shell width/shell lenght = 0,60 - 0,67 (mean = 0,63); shell height/shell length = 0,50 - 0,61 (mean = 0,55); shell height/shell width = 0,33 - 0,40 (mean = 0,35). Body of normal ancylid type; mantle pigmentation concentrated on the left side; three muscles are seen: a round posterior one on the left side, an elliptical muscle on the right anterior side and an almost almond-shaped one on the left anterior side. Tentacles with a medium core of black pigment. Pseudobranch two-lobed and folded, the dorsal lobe smaller than the vetral one. Ovotestis with 20 unbranched diverticula, around a short collecting canal. Ovispermiduct with an enlargement with several round outpocketings constituting the seminal vesicle. Carrefour as a round sac. Albumen gland almost cylindrical with several acinous diverticula. Elongated nidamental gland continous with the galndular wall of the uterus; uterus flattened and thin-walled. Spermathecal body almost rounded. Pear-shaped prostate without diverticula. Penial complex without flagellum but with well-developed ultra-penis and penis. Jaw horseshoe shaped. Radular forma 20.1.20; raquidian tooth quadricuspid, asymmetrical. The genus Laevapex Walker, 1903 is recorded for the first time in Brazil. It is easily distinguished from South American Gundlachia Pfeiffer, 1849 by its penial complex. Laevapex vazi is dedicated to Dr. Jorge Faria Vaz, from SUCEN-SP, who have been sent to me the specimens.

A Framework for Analyzing Language and Welfare

The paper proposes a general model that will encompass trade and social benefits of a common language, a preference for a variety of languages, the fundamental role of translators, an emotional attachment to maternal language, and the threat that globalization poses to the vast majority of languages. With respect to people’s emotional attachment, the model considers minorities to suffer losses from the subordinate status of their language. In addition, the model treats the threat to minority language as coming from the failure of the parents in the minority to transmit their maternal language (durably) to their children. Some familiar results occur. In particular, we encounter the usual social inefficiencies of decentralized solutions to language learning when the sole benefits of the learning are communicative benefits (though translation intervenes). However, these social inefficiencies assume a totally different air when the con-sumer gains of variety are brought in. One fundamental aim of the paper is to bring together contributions to the economics of language from labor economics, network externalities and international trade that are typically treated separately.

Biomphalaria obstructa (Morelet, 1849): a study of topotypic specimens (Mollusca: pulmonata: planorbidae)

A description of Biomphalaria obstructa (Morelet, 1849), based on specimens collected at its type locality - isla del carmen, state of Campeche, Mexico - is presented. The Shell is small, 13 mm in diameter, 3.5 mm in width and with 5.75 whorls in the largest specimen, thin, moderately lustrous and translucent, horn-colored. Whorls increasing regularly (neither slowly nor rapidly) in diameter, rounded on the periphery side, bluntly angular on the left. Suture well-marked, deeper on the left. Right side widely concave, with first whorl deeply situated and partly hidden by the next. Left side shallower than right one, largely flattened, with first whorl plaintly visible. Aperture roundly heart-shaped, usually in the same plane as the body whorl but somewhat deflected to the left (less frequently to the right) in some specimens. Peristome sharp, seldom blunt; a distinct callus on the parietal wall. A number of young shells develop one set (seldom more) of apertural lamellae which tend to be resorbed as the shell grows. Absence of renal ridge. Ovotestis with about 70 mostly unbrached diverticula. Seminal vesicle beset with well-developed knoblike to fingerlike diverticula. Vaginal pouch more or less developed. Spermatheca club-shaped when empty, egg-shaped when full, and with intermediate forms between those extremes. Spermathecal body usually somewhat longer than the duct. Prostate with 7 to 20 (mean 12.06 ± 2.51) usually short diverticula which give off plumpish branches spreading out in a fan shape and overlapping to some extent their immediate neighbors. Foremost prostatic diverticulum nearly always partially or completely inserted between the spermathecal body and the uterine wall. Penial sheath consistently narrower and shorter than the prepuce. Muscular coat of the penis consisting of an inner longitudinal and an outer circular layers. Ratios between organ lengths: caudal to cephalic parts of female duct = 0.55 to 1.37 (mean 0.85 +- 0.17); cephalic parte of female duct to penial complex = 1.36 to 2.81 ((mean 1.90 +- 0.33); penial sheath to prepuce = 042 to 0.96 (mean 0.67 +- 0.13). Comparison with Morelet’s type specimens of Planorbis orbiculus and P. retusus points to the identity of those nominal species with B. obstructa.

Les nanoparticules, une nouvelle arme contre le crime ?

Nanoparticles, a new tool to deter crime? The detection of fingermarks at a crime scene or on evidence related with a criminal affair constitutes one of the main tasks of the investigators. Fingerprints, due to their uniqueness and invariability in time, remain a key element of an identification process (being for suspects or victims). The main difficulty resides in the fact that, most of the time, fingermarks are not visible through naked eye due to their chemical composition and the small amount of material that is left on the scene. There are said to be latent and their detection requires the application of specific techniques (optical or chemical). If numerous efficient techniques currently exist, there is a continuing quest for developing new techniques or reagents with an enhanced sensitivity towards secretions and with an increased efficiency. This article gives an outline about some currently performed researches based on the use of functionalized nanoparticles to detect latent fingermarks.

Secondary choriocapillaritis in infectious chorioretinitis.

PURPOSE: To analyse the indocyanine green angiography (ICGA) patterns of hypofluorescence that are compatible with choriocapillaritis that occur secondarily to toxoplasmic retinochoroiditis (ToRC), ocular tuberculosis (including tuberculous choroiditis, TuCR and multifocal serpiginoid choroiditis, TMSC) and syphilitic chorioretinitis (SyCR). METHODS: This was a single centre, retrospective case review study. Patients with a diagnosis of ToRC, TuCR, TMSC or SyCR were identified, their charts were reviewed and fundus photographs, fluorescein angiography (FA) and ICGA pictures were assessed. RESULTS: Indocyanine green angiography was performed at the initial presentation in 63 of the 105 patients with ToRC, in 37 of the 38 patients with TuCR, in six of six patients with TMSC and in two of four patients with SyCR. The following four ICGA patterns indicated choriocapillaritis: extension of hypofluorescence beyond the hypofluorescence of the actual infectious focus as seen on fundus photography or FA (seen only in ToRC and TuCR); small dark dots around the infectious focus (seen only in ToRC); multiple 'confetti-like' hypofluorescent areas or hypofluorescent geographical confluent areas (seen only in TMSC); and widespread areas of nonperfusion visible only in ICGA (seen only in SyCR). CONCLUSIONS: Patients with secondary choriocapillaritis have distinct typical ICGA findings. ICGA is thus an important diagnostic tool that can provide an explanation for otherwise obscure visual loss and that might have diagnostic value for specific conditions like ToRC and SyCR.