Showing papers by "Aix-Marseille University published in 2007"

SALT2: using distant supernovae to improve the use of type Ia supernovae as distance indicators

Abstract: We present an empirical model of Type Ia supernovae spectro-photometric evolution with time. The model is built using a large data set including light-curves and spectra of both nearby and distant supernovae, the latter being observed by the SNLS collaboration. We derive the average spectral sequence of Type Ia supernovae and their main variability components including a color variation law. The model allows us to measure distance moduli in the spectral range 2500-8000 A with calculable uncertainties, including those arising from variability of spectral features. Thanks to the use of high-redshift SNe to model the rest-frame UV spectral energy distribution, we are able to derive improved distance estimates for SNe Ia in the redshift range 0.8

"Infotaxis" as a strategy for searching without gradients

Abstract: Chemotactic bacteria are guided towards the source of a nutrient by local concentration gradients. That works on the microscopic scale, but at larger scales such local cues are unreliable pointers — for example, wind or water currents may disperse odours sought by foraging animals. Using statistical techniques, Vergassola et al. have developed a general search algorithm for movement strategies based on the detection of sporadic cues and partial information. The strategy, termed 'infotaxis' as it maximizes the expected rate of information gain, could find application in the design of 'sniffer' robots. A computational model of odour plume propagation and experimental data are used to devise a general search algorithm for movement strategies in chemotaxis, based on sporadic cues and partial information. The strategy is termed 'infotaxis' as it locally maximizes the expected rate of information gain. Chemotactic bacteria rely on local concentration gradients to guide them towards the source of a nutrient1. Such local cues pointing towards the location of the source are not always available at macroscopic scales because mixing in a flowing medium breaks up regions of high concentration into random and disconnected patches. Thus, animals sensing odours in air or water detect them only intermittently as patches sweep by on the wind or currents2,3,4,5,6. A macroscopic searcher must devise a strategy of movement based on sporadic cues and partial information. Here we propose a search algorithm, which we call ‘infotaxis’, designed to work under such conditions. Any search process can be thought of as acquisition of information on source location; for infotaxis, information plays a role similar to concentration in chemotaxis. The infotaxis strategy locally maximizes the expected rate of information gain. We demonstrate its efficiency using a computational model of odour plume propagation and experimental data on mixing flows7. Infotactic trajectories feature ‘zigzagging’ and ‘casting’ paths similar to those observed in the flight of moths8. The proposed search algorithm is relevant to the design of olfactory robots9,10,11, but the general idea of infotaxis can be applied more broadly in the context of searching with sparse information.

Legumes Symbioses: Absence of Nod Genes in Photosynthetic Bradyrhizobia

Abstract: Leguminous plants (such as peas and soybeans) and rhizobial soil bacteria are symbiotic partners that communicate through molecular signaling pathways, resulting in the formation of nodules on legume roots and occasionally stems that house nitrogen-fixing bacteria. Nodule formation has been assumed to be exclusively initiated by the binding of bacterial, host-specific lipochito-oligosaccharidic Nod factors, encoded by the nodABC genes, to kinase-like receptors of the plant. Here we show by complete genome sequencing of two symbiotic, photosynthetic, Bradyrhizobium strains, BTAi1 and ORS278, that canonical nodABC genes and typical lipochito-oligosaccharidic Nod factors are not required for symbiosis in some legumes. Mutational analyses indicated that these unique rhizobia use an alternative pathway to initiate symbioses, where a purine derivative may play a key role in triggering nodule formation.

Evolution of symbiotic bacteria in the distal human intestine.

Abstract: The adult human intestine contains trillions of bacteria, representing hundreds of species and thousands of subspecies. Little is known about the selective pressures that have shaped and are shaping this community's component species, which are dominated by members of the Bacteroidetes and Firmicutes divisions. To examine how the intestinal environment affects microbial genome evolution, we have sequenced the genomes of two members of the normal distal human gut microbiota, Bacteroides vulgatus and Bacteroides distasonis, and by comparison with the few other sequenced gut and non-gut Bacteroidetes, analyzed their niche and habitat adaptations. The results show that lateral gene transfer, mobile elements, and gene amplification have played important roles in affecting the ability of gut-dwelling Bacteroidetes to vary their cell surface, sense their environment, and harvest nutrient resources present in the distal intestine. Our findings show that these processes have been a driving force in the adaptation of Bacteroidetes to the distal gut environment, and emphasize the importance of considering the evolution of humans from an additional perspective, namely the evolution of our microbiomes.

Chlororespiration and cyclic electron flow around PSI during photosynthesis and plant stress response

Abstract: Besides major photosynthetic complexes of oxygenic photosynthesis, new electron carriers have been identified in thylakoid membranes of higher plant chloroplasts. These minor components, located in the stroma lamellae, include a plastidial NAD(P)H dehydrogenase (NDH) complex and a plastid terminal plastoquinone oxidase (PTOX). The NDH complex, by reducing plastoquinones (PQs), participates in one of the two electron transfer pathways operating around photosystem I (PSI), the other likely involving a still uncharacterized ferredoxin-plastoquinone reductase (FQR) and the newly discovered PGR5. The existence of a complex network of mechanisms regulating expression and activity of the NDH complex, and the presence of higher amounts of NDH complex and PTOX in response to environmental stress conditions the phenotype of mutants, indicate that these components likely play a role in the acclimation of photosynthesis to changing environmental conditions. Based on recently published data, we propose that the NDH-dependent cyclic pathway around PSI participates to the ATP supply in conditions of high ATP demand (such as high temperature or water limitation) and together with PTOX regulates cyclic electron transfer activity by tuning the redox state of intersystem electron carriers. In response to severe stress conditions, PTOX associated to the NDH and/or the PGR5 pathway may also limit electron pressure on PSI acceptor and prevent PSI photoinhibition.

p27Kip1 independently promotes neuronal differentiation and migration in the cerebral cortex

Abstract: The generation of glutamatergic neurons by stem and progenitor cells is a complex process involving the tight coordination of multiple cellular activities, including cell cycle exit, initiation of neuronal differentiation and cell migration. The mechanisms that integrate these different events into a coherent program are not well understood. Here we show that the cyclin-dependent kinase inhibitor p27Kip1 plays an important role in neurogenesis in the mouse cerebral cortex, by promoting the differentiation and radial migration of cortical projection neurons. Importantly, p27Kip1 promotes neuronal differentiation and neuronal migration via two distinct mechanisms, which are themselves independent of the cell cycle regulatory function of p27Kip1. p27Kip1 inactivation by gene targeting or RNA interference results in neuronal differentiation and radial migration defects, demonstrating that p27Kip1 regulates cell migration in vivo. The differentiation defect, but not the migration defect, is rescued by overexpression of the proneural gene Neurogenin 2. p27Kip1 acts by stabilizing Neurogenin 2 protein, an activity carried by the N-terminal half of the protein. The migration defect resulting from p27Kp1 inactivation is rescued by blocking RhoA signalling, an activity that resides in the c-terminal half of p27Kip1. Thus, p27Kip1 plays a key role in cortical development, acting as a modular protein that independently regulates and couples multiple cellular pathways contributing to neurogenesis.

Dijet cross sections and parton densities in diffractive DIS at HERA

Abstract: Differential dijet cross sections in diffractive deep-inelastic scattering are measured with the H1 detector at HERA using an integrated luminosity of 51.5 pb−1. The selected events are of the type ep → eXY , where the system X contains at least two jets and is well separated in rapidity from the low mass proton dissociation system Y . The dijet data are compared with QCD predictions at next-to-leading order based on diffractive parton distribution functions previously extracted from measurements of inclusive diffractive deepinelastic scattering. The prediction describes the dijet data well at low and intermediate zIP (the fraction of the momentum of the diffractive exchange carried by the parton entering the hard interaction) where the gluon density is well determined from the inclusive diffractive data, supporting QCD factorisation. A new set of diffractive parton distribution functions is obtained through a simultaneous fit to the diffractive inclusive and dijet cross sections. This allows for a precise determination of both the diffractive quark and gluon distributions in the range 0.05 < zIP < 0.9. In particular, the precision on the gluon density at high momentum fractions is improved compared to previous extractions.

Validation and usefulness of a computer-assisted cup-positioning system in total hip arthroplasty. A prospective, randomized, controlled study.

Abstract: Background: Malpositioning of the acetabular component during total hip arthroplasty increases the risk of dislocation, reduces the range of motion, and can be responsible for early wear and loosening. The purpose of this study was to compare computer-assisted with freehand insertion of the acetabular component. Methods: A randomized, controlled, matched prospective study of two groups of thirty patients each was performed. In the first group, cup positioning was assisted by an imageless computer-assisted surgical system based on bone morphing. In the control group, the cup was placed freehand. All of the patients were operated on by the same surgeon through an anterolateral approach. Cup anteversion and abduction angles were measured on three-dimensional computed tomography reconstructions postoperatively for each patient by an independent observer using special cup-evaluation software. Results: There were sixteen men and fourteen women in each group, and the mean body-mass index was approximately 25 in each group. The computer-assisted procedure took a mean of twelve minutes longer than the freehand procedure. Fifty-seven percent (seventeen) of the thirty cups placed freehand and 20% (six) of the thirty in the computer-assisted group were outside of the defined safe zone (outliers). This difference was significant (p = 0.002). There were no differences between the computer-assisted group and the freehand-placement group with regard to the mean abduction and anteversion angles, but there was a significant heterogeneity of variances, with the lowest variations in the computer-assisted group. Conclusions: Use of an imageless navigation system can improve cup positioning in total hip arthroplasty by reducing the percentage of outliers. Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.

Stereoelectroencephalography in presurgical assessment of MRI-negative epilepsy

Abstract: According to most existing literature, the absence of an MRI lesion is generally associated with poorer prognosis in resective epilepsy surgery. Delineation of the epileptogenic zone (EZ) by intracranial recording is usually required but is perceived to be more difficult in 'MRI negative' cases. Most previous studies have used subdural recording and there is relatively less published data on stereoelectroencephalography (SEEG). The objective of this study was to report the experience of our group in using SEEG in presurgical evaluation, comparing its effectiveness in normal and lesional MRI cases. One hundred consecutive patients undergoing SEEG for presurgical assessment were studied. Forty-three patients out of one hundred (43%) had normal MRI and 57 (57%) had lesional MRI. Successful localization was achieved with no difference between these two groups, in 41/43 (95%) normal MRI and in 55/57 (96%) lesional MRI cases (P = 1.00). Surgery was proposed in 84/100 patients and contraindicated in 16/100 with no significant difference between lesional and MRI-negative groups (P > 0.05). At 1 year follow-up, 11/20 (55%) of those having undergone cortectomy in the MRI-negative group and 21/40 (53%) in the lesional MRI group were entirely seizure free (P > 0.05) and these proportions were maintained at 2 years follow-up. Significant improvement in seizure control (ILAE outcome groups 1-4) was achieved in >90% cases with no difference between groups (P > 0.05). Of MRI-negative cases that underwent surgery, 10/23 (43%) had focal cortical dysplasia. This series showed that SEEG was equally effective in the presurgical evaluation of MRI-negative and lesional epilepsies.

High efficacy and safety profile of fractionated doses of Mylotarg as induction therapy in patients with relapsed acute myeloblastic leukemia: a prospective study of the alfa group

Abstract: Pivotal phase II studies in acute myeloblastic leukemia (AML) patients in first relapse have used gemtuzumab ozogamicin (GO) (Mylotarg) at a dose of 9 mg/m(2) on days 1 and 14. These studies showed a 26% response rate (13% complete remission (CR) and 13% CRp (complete remission with incomplete platelet recovery)) but with high degree of hematological and liver toxicities. Based on in vitro studies showing a re-expression of CD33 antigenic sites on the cell surface of blasts cells after exposure to GO, we hypothesized that fractionated doses of GO may be efficient and better tolerated. Fifty-seven patients with AML in first relapse received GO at a dose of 3 mg/m(2) on days 1, 4 and 7 for one course. Fifteen patients (26%) achieved CR and four (7%) CRp. Remission rate correlated strongly with P-glycoprotein and MRP1 activities. The median relapse-free survival was 11 months, similar for CR or CRp patients. Median duration of neutropenia < 500/microl and thrombocytopenia < 50,000/microl were, respectively, 23 and 21 days. No grade 3 or 4 liver toxicity was observed. No veno-occlusive disease occurred after GO or after hematopoietic stem cell transplantation given after GO in seven patients. Mylotarg administered in fractionated doses demonstrated an excellent efficacy/safety profile.

Non-HACEK gram-negative bacillus endocarditis.

Abstract: Endocarditis caused by non-HACEK organisms (species other than Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella species) has lon...

Modulators of Small- and Intermediate-Conductance Calcium-Activated Potassium Channels and their Therapeutic Indications

Abstract: Calcium-activated potassium channels modulate calcium signaling cascades and membrane potential in both excitable and non-excitable cells. In this article we will review the physiological properties, the structure activity relationships of the existing peptide and small molecule modulators and the therapeutic importance of the three small-conductance channels KCa2.1-KCa2.3 (a.k.a. SK1-SK3) and the intermediate-conductance channel KCa3.1 (a.k.a. IKCa1). The apamin-sensitive KCa2 channels contribute to the medium afterhyperpolarization and are crucial regulators of neuronal excitability. Based on behavioral studies with apamin and on observations made in several transgenic mouse models, KCa2 channels have been proposed as targets for the treatment of ataxia, epilepsy, memory disorders and possibly schizophrenia and Parkinson's disease. In contrast, KCa3.1 channels are found in lymphocytes, erythrocytes, fibroblasts, proliferating vascular smooth muscle cells, vascular endothelium and intestinal and airway epithelia and are therefore regarded as targets for various diseases involving these tissues. Since two classes of potent and selective small molecule KCa3.1 blocker, triarylmethanes and cyclohexadienes, have been identified, several of these postulates have already been validated in animal models. The triarylmethane ICA-17043 is currently in phase III clinical trials for sickle cell anemia while another triarylmethane, TRAM-34, has been shown to prevent vascular restenosis in rats and experimental autoimmune encephalomyelitis in mice. Experiments showing that a cyclohexadiene KCa3.1 blocker reduces infarct volume in a rat subdural hematoma model further suggest KCa3.1 as a target for the treatment of traumatic and possibly ischemic brain injury. Taken together KCa2 and KCa3.1 channels constitute attractive new targets for several diseases that currently have no effective therapies.

Hydrogen production by Chlamydomonas reinhardtii : an elaborate interplay of electron sources and sinks

Abstract: The unicellular green alga Chlamydomonas reinhardtii possesses a [FeFe]-hydrogenase HydA1 (EC 1.12.7.2), which is coupled to the photosynthetic electron transport chain. Large amounts of H2 are produced in a light-dependent reaction for several days when C. reinhardtii cells are deprived of sulfur. Under these conditions, the cells drastically change their physiology from aerobic photosynthetic growth to an anaerobic resting state. The understanding of the underlying physiological processes is not only important for getting further insights into the adaptability of photosynthesis, but will help to optimize the biotechnological application of algae as H2 producers. Two of the still most disputed questions regarding H2 generation by C. reinhardtii concern the electron source for H2 evolution and the competition of the hydrogenase with alternative electron sinks. We analyzed the H2 metabolism of S-depleted C. reinhardtii cultures utilizing a special mass spectrometer setup and investigated the influence of photosystem II (PSII)- or ribulosebisphosphate-carboxylase/oxygenase (Rubisco)-deficiency. We show that electrons for H2-production are provided both by PSII activity and by a non-photochemical plastoquinone reduction pathway, which is dependent on previous PSII activity. In a Rubisco-deficient strain, which produces H2 also in the presence of sulfur, H2 generation seems to be the only significant electron sink for PSII activity and rescues this strain at least partially from a light-sensitive phenotype. The latter indicates that the down-regulation of assimilatory pathways in S-deprived C. reinhardtii cells is one of the important prerequisites for a sustained H2 evolution.

Lumpy Price Adjustments: A Microeconometric Analysis

Abstract: This paper presents a simple model of state-dependent pricing that allows identification of the relative importance of the degree of price rigidity that is inherent to the price setting mechanism (intrinsic) and that which is due to the price's driving variables (extrinsic). Using two data sets consisting of a large fraction of the price quotes used to compute the Belgian and French CPI, we are able to assess the role of intrinsic and extrinsic price stickiness in explaining the occurrence and magnitude of price changes at the outlet level. We find that infrequent price changes are not necessarily associated with large adjustment costs. Indeed, extrinsic rigidity appears to be significant in many cases. We also find that asymmetry in the price adjustment could be due to trends in marginal costs and/or desired mark-ups rather than asymmetric cost of adjustment bands.

Intrinsic apoptotic pathways of gingival epithelial cells modulated by Porphyromonas gingivalis.

Abstract: Porphyromonas gingivalis can inhibit chemically induced apoptosis in primary cultures of gingival epithelial cells through blocking activation of the effector caspase-3. The anti-apoptotic phenotype of P. gingivalis is conserved across strains and does not depend on the presence of fimbriae, as fimbriae-deficient mutants and a naturally occurring non-fimbriated strain were able to impede apoptosis. To dissect the survival pathways modulated by P. gingivalis, protein and gene expression of a number of components of apoptotic death pathways were investigated. P. gingivalis infection of epithelial cells resulted in the phosphorylation of JAK1 and Stat3. Quantitative real-time reverse transcription polymerase chain reaction showed that expression of Survivin and Stat3 itself, targets of activated Stat3, were elevated in P. gingivalis-infected cells. siRNA knockdown of JAK1, in combination with knockdown of Akt, abrogated the ability of P. gingivalis to block apoptosis. In contrast, cIAP-1 and cIAP-2 were not differentially regulated at either the protein or mRNA levels by P. gingivalis. One mechanism by which P. gingivalis can block apoptotic pathways in gingival epithelial cells therefore is through manipulation of the JAK/Stat pathway that controls the intrinsic mitochondrial cell death pathways. Induction of a pro-survival phenotype may prevent programmed host cell death and aid survival of P. gingivalis within gingival epithelial cells.

Single-trial analysis of oddball event-related potentials in simultaneous EEG-fMRI

Abstract: There has recently been a growing interest in the use of simultaneous electroencephalography (EEG) and functional MRI (fMRI) for evoked activity in cognitive paradigms, thereby obtaining functional datasets with both high spatial and temporal resolution. The simultaneous recording permits obtaining event-related potentials (ERPs) and MR images in the same environment, conditions of stimulation, and subject state; it also enables tracing the joint fluctuations of EEG and fMRI signals. The goal of this study was to investigate the possibility of tracking the trial-to-trial changes in event-related EEG activity, and of using this information as a parameter in fMRI analysis. We used an auditory oddball paradigm and obtained single-trial amplitude and latency features from the EEG acquired during fMRI scanning. The single-trial P300 latency presented significant correlation with parameters external to the EEG (target-to-target interval and reaction time). Moreover, we obtained significant fMRI activations for the modulation by P300 amplitude and latency, both at the single-subject and at the group level. Our results indicate that, in line with other studies, the EEG can bring a new dimension to the field of fMRI analysis by providing fine temporal information on the fluctuations in brain activity.

Vitamin E is essential for the tolerance of Arabidopsis thaliana to metal‐induced oxidative stress

Abstract: Arabidopsis (Arabidopsis thaliana) plants were grown in a hydroponic culture system for 7 to 14 d in the absence or presence of 75 microM Cd or 75 microM Cu. The Cu treatment resulted in visual leaf symptoms, together with anthocyanin accumulation and loss of turgor. Pronounced lipid peroxidation, which was detected by autoluminescence imaging and malondialdehyde titration, was observed in Cu-treated leaves. The Cd treatment also resulted in loss of leaf pigments but lipid peroxidation and oxidative stress were less pronounced than in the leaves exposed to Cu. Analysis of low-molecular-weight chloroplast and cytosolic antioxidants (ascorbate, glutathione, tocopherols, carotenoids) and antioxidant enzymes (thiol-based reductases and peroxidases) revealed relatively few responses to metal exposure. However, there was a marked increase in vitamin E (alpha-tocopherol) in response to Cd and Cu treatments. Ascorbate increased significantly in Cu-exposed leaves. Other antioxidants either remained stable or decreased in response to metal stress. Transcripts encoding enzymes of the vitamin E biosynthetic pathway were increased in response to metal exposure. In particular, VTE2 mRNA was enhanced in Cu- and Cd-treated plants, while VTE5 and hydroxylpyruvate dioxygenase (HPPD) mRNAs were only up-regulated in Cd-treated plants. Consistent increases in HPPD transcripts and protein were observed. The vitamin E-deficient (vte1) mutant exhibited an enhanced sensitivity towards both metals relative to the wild-type (WT) control. Unlike the vte1 mutants, which showed enhanced lipid peroxidation and oxidative stress in the presence of Cu or Cd, the ascorbate-deficient (vtc2) mutant showed WT responses to metal exposure. Taken together, these results demonstrate that vitamin E plays a crucial role in the tolerance of Arabidopsis to oxidative stress induced by heavy metals such as Cu and Cd.

Maternal microchimerism in peripheral blood in type 1 diabetes and pancreatic islet β cell microchimerism

Abstract: Maternal cells have recently been found in the circulation and tissues of mothers' immune-competent children, including in adult life, and is referred to as maternal microchimerism (MMc). Whether MMc confers benefits during development or later in life or sometimes has adverse effects is unknown. Type 1 diabetes (T1D) is an autoimmune disease that primarily affects children and young adults. To identify and quantify MMc, we developed a panel of quantitative PCR assays targeting nontransmitted, nonshared maternal-specific HLA alleles. MMc was assayed in peripheral blood from 172 individuals, 94 with T1D, 54 unaffected siblings, and 24 unrelated healthy subjects. MMc levels, expressed as the genome equivalent per 100,000 proband cells, were significantly higher in T1D patients than unaffected siblings and healthy subjects. Medians and ranges, respectively, were 0.09 (0–530), 0 (0–153), and 0 (0–7.9). Differences between groups were evident irrespective of HLA genotypes. However, for patients with the T1D-associated DQB1*0302-DRB1*04 haplotype, MMc was found more often when the haplotype was paternally (70%) rather than maternally transmitted (14%). In other studies, we looked for female islet β cells in four male pancreases from autopsies, one from a T1D patient, employing FISH for X and Y chromosomes with concomitant CD45 and β cell insulin staining. Female islet β cells (presumed maternal) formed 0.39–0.96% of the total, whereas female hematopoietic cells were very rare. Thus, T1D patients have higher levels of MMc in their circulation than unaffected siblings and healthy individuals, and MMc contributes to islet β cells in a mother's progeny.

Self-Invertible 2D Log-Gabor Wavelets

Abstract: Orthogonal and biorthogonal wavelets became very popular image processing tools but exhibit major drawbacks, namely a poor resolution in orientation and the lack of translation invariance due to aliasing between subbands. Alternative multiresolution transforms which specifically solve these drawbacks have been proposed. These transforms are generally overcomplete and consequently offer large degrees of freedom in their design. At the same time their optimization gets a challenging task. We propose here the construction of log-Gabor wavelet transforms which allow exact reconstruction and strengthen the excellent mathematical properties of the Gabor filters. Two major improvements on the previous Gabor wavelet schemes are proposed: first the highest frequency bands are covered by narrowly localized oriented filters. Secondly, the set of filters cover uniformly the Fourier domain including the highest and lowest frequencies and thus exact reconstruction is achieved using the same filters in both the direct and the inverse transforms (which means that the transform is self-invertible). The present transform not only achieves important mathematical properties, it also follows as much as possible the knowledge on the receptive field properties of the simple cells of the Primary Visual Cortex (V1) and on the statistics of natural images. Compared to the state of the art, the log-Gabor wavelets show excellent ability to segregate the image information (e.g. the contrast edges) from spatially incoherent Gaussian noise by hard thresholding, and then to represent image features through a reduced set of large magnitude coefficients. Such characteristics make the transform a promising tool for processing natural images.

Enhanced SPR sensitivity using periodic metallic structures

Abstract: A sinusoidal silver grating is used to create a six-fold enhancement of the SPR response compared to a flat surface. The grating parameters are chosen to create a surface plasmon bandgap and it is shown that the enhancement of the sensitivity to bulk sample index occurs when operating near the bandgap. The Kretschmann configuration is considered and the Boundary Element Method is used to generate the dispersion curves.

Tracing past human male movements in northern/eastern Africa and western Eurasia: new clues from Y-chromosomal haplogroups E-M78 and J-M12.

Abstract: Detailed population data were obtained on the distribution of novel biallelic markers that finely dissect the human Y-chromosome haplogroup E-M78. Among 6,501 Y chromosomes sampled in 81 human populations worldwide, we found 517 E-M78 chromosomes and assigned them to 10 subhaplogroups. Eleven microsatellite loci were used to further evaluate subhaplogroup internal diversification. The geographic and quantitative analyses of haplogroup and microsatellite diversity is strongly suggestive of a northeastern African origin of E-M78, with a corridor for bidirectional migrations between northeastern and eastern Africa (at least 2 episodes between 23.9-17.3 ky and 18.0-5.9 ky ago), trans-Mediterranean migrations directly from northern Africa to Europe (mainly in the last 13.0 ky), and flow from northeastern Africa to western Asia between 20.0 and 6.8 ky ago. A single clade within E-M78 (E-V13) highlights a range expansion in the Bronze Age of southeastern Europe, which is also detected by haplogroup J-M12. Phylogeography pattern of molecular radiation and coalescence estimates for both haplogroups are similar and reveal that the genetic landscape of this region is, to a large extent, the consequence of a recent population growth in situ rather than the result of a mere flow of western Asian migrants in the early Neolithic. Our results not only provide a refinement of previous evolutionary hypotheses but also well-defined time frames for past human movements both in northern/eastern Africa and western Eurasia.

Applying nonlinear resonant ultrasound spectroscopy to improving thermal damage assessment in concrete

Abstract: Nonlinear resonant ultrasound spectroscopy (NRUS) consists of evaluating one or more resonant frequency peak shifts while increasing excitation amplitude. NRUS exhibits high sensitivity to global damage in a large group of materials. Most studies conducted to date are aimed at interrogating the mechanical damage influence on the nonlinear response, applying bending, or longitudinal modes. The sensitivity of NRUS using longitudinal modes and the comparison of the results with a classical linear method to monitor progressive thermal damage (isotropic) of concrete are studied in this paper. In addition, feasibility and sensitivity of applying shear modes for the NRUS method are explored.

The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant Luminous Red Galaxy

Abstract: We report the discovery of an almost complete (~300°) Einstein ring of diameter 10'' in Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5). Spectroscopic data from the 6 m telescope of the Special Astrophysical Observatory reveal that the deflecting galaxy has a line-of-sight velocity dispersion in excess of 400 km s-1 and a redshift of 0.444, while the source is a star-forming galaxy with a redshift of 2.379. From its color, luminosity, and velocity dispersion, we argue that this is the most massive galaxy lens hitherto discovered.