Sound and light from fractures in scintillators

Prompted by intriguing events observed in certain particle-physics searches for rare events, we study light and acoustic emission simultaneously in some inorganic scintillators subject to mechanical stress. We observe mechanoluminescence in ${Bi}_4{Ge}_{3}{O}_{12}$, ${CdWO}_{4}$ and ${ZnWO}_{4}$, in various mechanical configurations at room temperature and ambient pressure. We analyze how the light emission is correlated to acoustic emission during fracture. For ${Bi}_4{Ge}_{3}{O}_{12}$, we set a lower bound on the energy of the emitted light, and deduce that the fraction of elastic energy converted to light is at least $3 \times 10^{-5}$

Contribution des fourmis à la lutte biologique contre les Loranthaceae

Les Loranthaceae sont des plantes parasites qui causent de nombreux dommages sur les plantes hôtes se traduisant par une réduction de la floraison, de la fructification et de la production. Dans le but de trouver une méthode de lutte efficace contre les Loranthaceae, une étude relative à l’activité myrmécophile a été menée au verger de la chefferie de Ndogbong. Un inventaire de la myrmécofaune a été réalisé sur 16 individus de Theobroma cacao dont 9 parasités et 7 non parasités. Trois espèces de Loranthaceae ont été recensées: Phragmanthera batangae (Engler) S. Balle, P. capitata (Sprengel) S. Balle et Tapinanthus preussii (Engler) Van Teghem. Trois sous-familles de fourmis ont été identifiées : les Ponerinae (Odontomachus troglodytes Santschi), les Formicinae (Camponotus sp.) et les Myrmicinae (Crematogaster sp., C. decacrema, C. oxygyne, et Pheidole megacephala Fabricius). Deux espèces de fourmis ont été présentes sur les fleurs et les fruits de P. capitata et T. preussii et contribuent à la lutte biologique contre les Loranthaceae.Mots clés: Myrmécofaune, lutte, Loranthaceae, Ndogbong, Theobroma caca

Myrmécofaune arboricole associée aux couples Phragmanthera capitata (Sprengel) S. Balle/ hôte au verger de la chefferie de Ndogbong (Douala, Cameroun)

Parmi les Loranthaceae, l’espèce Phragmanthera capitata s’est mieux adaptée aux conditions du milieu modifié par l’homme et aux arbres cultivés ou spontanés devenant un véritable fléau agronomique. La méthode de lutte ciblée plus prometteuse ne peut être satisfaisante que si les mécanismes qui régulent l’adaptation des Loranthaceae à leurs hôtes cultivés ou spontanés sont identifiés et maîtrisés. Dans cette optique, une étude de la myrmécofaune arboricole a été menée sur trois couples P. capitata/hôte au verger de la chefferie de Ndogbong. Auparavant, un inventaire exhaustif de tous les arbres parasités ou non et de la myrmécofaune du verger de la chefferie de Ndogbong (Douala) a été entrepris et toutes les touffes de P. capitata comptabilisés sur les arbreshôtes qui en possédaient. Tous les arbres du verger sont exotiques excepté Spondias mangifera. Le taux de parasitisme est de 42,85%. Quatre espèces de fourmis (Crematogaster sp. 1, Crematogaster sp.2, Pheidole megacephala et Camponotus sp.) ont une activité fourragère notamment florifère sur les individus de P. capitata. Leur densité varie avec la floraison et semble liée à la chute des boutons floraux et des fleurs. Ces fourmis pourraient constituer des forces d’organisation et d’évolution exploitables dans la lutte biologique contre les Loranthaceae. Mots clés: Loranthaceae, myrmécofaune arboricole, plantes hôtes

In vivo effects of traditional ayurvedic formulations in Drosophila melanogaster model relate with therapeutic applications

Background: Ayurveda represents the traditional medicine system of India. Since mechanistic details of therapy in terms of current biology are not available in Ayurvedic literature, modern scientific studies are necessary to understand its major concepts and procedures. It is necessary to examine effects of the whole Ayurvedic formulations rather than their “active” components as is done in most current studies. Methods: We tested two different categories of formulations, a Rasayana (Amalaki Rasayana or AR, an herbal derivative) and a Bhasma (Rasa-Sindoor or RS, an organo-metallic derivative of mercury), for effects on longevity, development, fecundity, stress-tolerance, and heterogeneous nuclear ribonucleoprotein (hnRNP) levels of Drosophila melanogaster using at least 200 larvae or flies for each assay. Results: A 0.5% (weight/volume) supplement of AR or RS affected life-history and other physiological traits in distinct ways. While the size of salivary glands, hnRNP levels in larval tissues, and thermotolerance of larvae/adult flies improved significantly following feeding either of the two formulations, the median life span and starvation resistance improved only with AR. Feeding on AR or RS supplemented food improved fecundity differently. Feeding of larvae and adults with AR increased the fecundity while the same with RS had opposite effect. On the contrary, feeding larvae on normal food and adults on AR supplement had no effect on fecundity but a comparable regime of feeding on RS-supplemented food improved fecundity. RS feeding did not cause heavy metal toxicity. Conclusions: The present study with two Ayurvedic formulations reveals formulation-specific effects on several parameters of the fly's life, which seem to generally agree with their recommended human usages in Ayurvedic practices. Thus, Drosophila, with its very rich genetic tools and well-worked-out developmental pathways promises to be a very good model for examining the cellular and molecular bases of the effects of different Ayurvedic formulations

Discovery of optical pulsations in V2116 Ophiuchi/GX 1+4

We report the detection of pulsations with $\sim 124$ s period in V2116 Oph, the optical counterpart of the low-mass X-ray binary GX 1+4. The pulsations are sinusoidal with modulation amplitude of up to 4% in blue light and were observed in ten different observing sessions during 1996 April-August using a CCD photometer at the 1.6-m and 0.6-m telescopes of Laborat\'orio Nacional de Astrof\'{\i}sica, in Brazil. The pulsations were also observed with the $UBVRI$ fast photometer. With only one exception the observed optical periods are consistent with those observed by the BATSE instrument on board the Compton Gamma Ray Observatory at the same epoch. There is a definite correlation between the observability of pulsations and the optical brightness of the system: V2116~Oph had $R$ magnitude in the range $15.3-15.5$ when the pulsed signal was detected, and $R = 16.0-17.7$ when no pulsations were present. The discovery makes GX 1+4 only the third of $\sim 35$ accretion-powered X-ray pulsars to be firmly detected as a pulsating source in the optical. The presence of flickering and pulsations in V2116 Oph adds strong evidence for an accretion disk scenario in this system. The absolute magnitude of the pulsed component on 1996 May 27 is estimated to be $M_V \sim -1.5$. The implied dimensions for the emitting region are 1.1 R_{\sun}, 3.2 R_{\sun}, and 7.0 R_{\sun}, for black-body spectral distributions with $T = 10^5$ K, $2 \times 10^4$ K, and $1 \times 10^4$ K, respectively.Comment: 9 pages, 3 figures in PostScript, latex, accepted for publication on the Astrophysical Journal Letter

MATERIAL CHARACTERIZATION OF SUPERCONDUCTING NANO CRYSTALLINE CERAMIC YSrBiCuO BY THERMAL TECHNIQUES

The nano-sized ceramic superconducting material YSBCO having perovskite structure was prepared according to the chemical formula by the thermo chemical solid state reaction technique using a high-energy ball milling process through mechanically assisted synthesis. It was characterized by XRD, SEM and EDX. Here the authours studied the thermal characterization using TGA, DTA and DSC

Extraordinary electrical conductance through amorphous non-conducting polymers under vibrational strong coupling

Achieving electrical conductance in amorphous non-doped polymers is a challenging task. Here, we show that vibrational strong coupling of the aromatic C-H(D) out-of-plane bending modes of polystyrene, deuterated polystyrene, and poly (benzyl methacrylate) to the vacuum electromagnetic field of the cavity enhance the electrical conductivity by at least six orders of magnitude compared to the uncoupled polymers. The conductance is thermally activated at the onset of strong coupling. It becomes temperature and cavity path length independent at the highest coupling strengths, giving rise to the extraordinary electrical conductance in these polymers. The electrical characterizations are performed without external light excitation, demonstrating the role of quantum light in enhancing the long-range coherent transport even in amorphous non-conducting polymers.Comment: Sunil Kumar and Subha Biswas contributed equall

Associations of lifestyle and vascular risk factors with Alzheimer\u27s brain biomarker changes during middle age: a 3 year longitudinal study in the broader New York City area

Objective To investigate the associations between lifestyle and vascular risk factors and changes in Alzheimer’s disease (AD) biomarkers (beta-amyloid load via 11C-PiB PET, glucose metabolism via 18F-FDG PET and neurodegeneration via structural MRI) and global cognition in middle-aged asymptomatic participants at risk for AD. Design Prospective, longitudinal. Setting The study was conducted at New York University Langone/Weill Cornell Medical Centres in New York City. Participants Seventy cognitively normal participants from multiple community sources, aged 30–60 years with lifestyle measures (diet, intellectual activity and physical activity), vascular risk measures and two imaging biomarkers visits over at least 2 years, were included in the study. Outcome measures We examined MRI-based cortical thickness, fluoro-deoxy-glucose (FDG) glucose metabolism and PiB beta-amyloid in AD-vulnerable regions. A global cognitive z-score served as our summary cognition measure. We used regression change models to investigate the associations of clinical, lifestyle and vascular risk measures with changes in AD biomarkers and global cognition. Results Diet influenced changes in glucose metabolism, but not amyloid or cortical thickness changes. With and without accounting for demographic measures, vascular risk and baseline FDG measures, lower adherence to a Mediterranean-style diet was associated with faster rates of FDG decline in the posterior cingulate cortex (p≤0.05) and marginally in the frontal cortex (p=0.07). None of the other lifestyle variables or vascular measures showed associations with AD biomarker changes. Higher baseline plasma homocysteine was associated with faster rates of decline in global cognition, with and without accounting for lifestyle and biomarker measures (p=0.048). None of the lifestyle variables were associated with cognition. Conclusions Diet influenced brain glucose metabolism in middle-aged participants, while plasma homocysteine explained variability in cognitive performance. These findings suggest that these modifiable risk factors affect AD risk through different pathways and support further investigation of risk reduction strategies in midlife

Community health workers in rural India: analysing the opportunities and challenges Accredited Social Health Activists (ASHAs) face in realising their multiple roles

Background: Globally, there is increasing interest in community health worker’s (CHW) performance; however, there are gaps in the evidence with respect to CHWs’ role in community participation and empowerment. Accredited Social Health Activists (ASHAs), whose roles include social activism, are the key cadre in India’s CHW programme which is designed to improve maternal and child health. In a diverse country like India, there is a need to understand how the ASHA programme operates in different underserved Indian contexts, such as rural Manipur. Methods: We undertook qualitative research to explore stakeholders’ perceptions and experiences of the ASHA scheme in strengthening maternal health and uncover the opportunities and challenges ASHAs face in realising their multiple roles in rural Manipur, India. Data was collected through in-depth interviews (n = 18) and focus group discussions (n = 3 FGDs, 18 participants). Participants included ASHAs, key stakeholders and community members. They were purposively sampled based on remoteness of villages and primary health centres to capture diverse and relevant constituencies, as we believed experiences of ASHAs can be shaped by remoteness. Data were analysed using the thematic framework approach. Results: Findings suggested that ASHAs are mostly understood as link workers. ASHA’s ability to address the immediate needs of rural and marginalised communities meant that they were valued as service providers. The programme is perceived to be beneficial as it improves awareness and behaviour change towards maternal care. However, there are a number of challenges; the selection of ASHAs is influenced by power structures and poor community sensitisation of the ASHA programme presents a major risk to success and sustainability. The primary health centres which ASHAs link to are ill-equipped. Thus, ASHAs experience adverse consequences in their ability to inspire trust and credibility in the community. Small and irregular monetary incentives demotivate ASHAs. Finally, ASHAs had limited knowledge about their role as an ‘activist’ and how to realise this. Conclusions: ASHAs are valued for their contribution towards maternal health education and for their ability to provide basic biomedical care, but their role as social activists is much less visible as envisioned in the ASHA operational guideline. Access by ASHAs to fair monetary incentives commensurate with effort coupled with the poor functionality of the health system are critical elements limiting the role of ASHAs both within the health system and within communities in rural Manipur

Basement membrane proteins as a substrate for efficient Trypanosoma brucei differentiation in vitro

The ability to reproduce the developmental events of trypanosomes that occur in their mammalian host in vitro offers significant potential to assist in understanding of the underlying biology of the process. For example, the transition from bloodstream slender to bloodstream stumpy forms is a quorum-sensing response to the parasite-derived peptidase digestion products of environmental proteins. As an abundant physiological substrate in vivo, we studied the ability of a basement membrane matrix enriched gel (BME) in the culture medium to support differentiation of pleomorphic Trypanosoma brucei to stumpy forms. BME comprises extracellular matrix proteins, which are among the most abundant proteins found in connective tissues in mammals and known substrates of parasite-released peptidases. We previously showed that two of these released peptidases are involved in generating a signal that promotes slender-to-stumpy differentiation. Here, we tested the ability of basement membrane extract to enhance parasite differentiation through its provision of suitable substrates to generate the quorum sensing signal, namely oligopeptides. Our results show that when grown in the presence of BME, T. brucei pleomorphic cells arrest at the G0/1 phase of the cell cycle and express the differentiation marker PAD1, the response being restricted to differentiation-competent parasites. Further, the stumpy forms generated in BME medium are able to efficiently proceed onto the next life cycle stage in vitro, procyclic forms, when incubated with cis-aconitate, further validating the in vitro BME differentiation system. Hence, BME provides a suitable in vitro substrate able to accurately recapitulate physiological parasite differentiation without the use of experimental animals