Memory effect in triglycine sulfate induced by a transverse electric field: specific heat measurement

The influence of a transverse electric field in the specific heat of triglycine sulphate (TGS) has been studied. The specific heat of TGS has been measured heating the sample from ferroelectric to paraelectric phase after prolonged transverse electric field (i.e. perpendicular to the ferroelectric axis). It is shown that the specific heat of TGS can remember the temperature $T_s$ at which the transverse field was previously applied.Comment: ReVTeX4 Twocolumn 4 pages, 4 figure

Paysans, bergers et colporteurs: La vie d'un village de l'âge du Fer dans la Péninsule de Oman (AM1-Thuqeibah, Sharjah, E.A.U.)

Les fouilles archéologiques menées en al Madam (Sharjah, Emirats Arabes Unis) répondent à diverses questions restées en suspens relatives à l’histoire et l’archéologie del’âge du Fer dans la Péninsule d’Oman. L’ètroite collaboration entre l’histoire, l’archéologie et les sciences naturelles peutre trouver les modes de vie et l’histoire quotidienne d’une petite communauté rurale. Il a même aidé à découvrir des facettes imprévuesArchaeological excavations carried out in the al Madam oasis (Sharjah, UAE) are responding to various questions related to the history and archaeology of the Iron Age in the Oman Peninsula. Close cooperation between history, archaeology and natural sciences can recover the way of life and every day story of a small rural community, even discovering unexpected facets

Intraretinal Transplantation for Rod-Cell Replacement in Light-Damaged Retinas

Blindness from retinal disease is often the consequence of extensive damage to the photoreceptor cell population, while other cell types which form the neural retina are relatively spared. In this setting, transplantation of photoreceptor cells could offer hope for the restoration of some degree of visual function. We testd the feasibility of this approach by transplanting immature retinal cells into the eyes of adult rats affected by late stage phototoxic retinopathy, which are almost totally devoid of photoreceptor cells

Stem cells as a therapeutic tool for the blind: biology and future prospects

Retinal degeneration due to genetic, diabetic and age-related disease is the most common cause of blindness in the developed world. Blindness occurs through the loss of the light-sensing photoreceptors; to restore vision, it would be necessary to introduce alternative photosensitive components into the eye. The recent development of an electronic prosthesis placed beneath the severely diseased retina has shown that subretinal stimulation may restore some visual function in blind patients. This proves that residual retinal circuits can be reawakened after photoreceptor loss and defines a goal for stem-cell-based therapy to replace photoreceptors. Advances in reprogramming adult cells have shown how it may be possible to generate autologous stem cells for transplantation without the need for an embryo donor. The recent success in culturing a whole optic cup in vitro has shown how large numbers of photoreceptors might be generated from embryonic stem cells. Taken together, these threads of discovery provide the basis for optimism for the development of a stem-cell-based strategy for the treatment of retinal blindness

Experimental method to determine specific heat and transition enthalpy at a first order phase transition: fundamentals and application to a NiMnIn Heusler alloy

A new method that characterizes thermal properties during a first-order phase transition is described. The technique consists in exciting the sample by a series of constant frequency thermal pulses which one in every N pulses (N is a small number like four) being exceedingly large in amplitude. This pulse induces phase transformation which is inhibited during the following smaller pulses due to thermal hysteresis. That way the specific heat for a given mixture of phases can be determined. The results obtained are independent of experimental parameters like the rate and the amplitude of the pulses, unlike what happens in other calorimetric techniques. The method also provides the enthalpy excess by analyzing the energy balance between the dissipated heat and the heat flowing during each pulse of measurement. The protocol is tested to analyze the phase transitions of a Heusler alloy Ni 50.54 Mn 33.65 In 15.82 . The paramagnetic-ferromagnetic transition for the austenite phase is continuous and the specific heat shows a lambda anomaly. The martensitic phase transition shows a first-order character and the specific heat follows a step-like behaviour in contrast with previously reported large-peak anomalies.Comment: 15 pages, 5 figure