Vitamin B2-based blue-light photoreceptors in the retinohypothalamic tract as the photoactive pigments for setting the circadian clock in mammals

In mammals the retina contains photoactive molecules responsible for both vision and circadian photoresponse systems. Opsins, which are located in rods and cones, are the pigments for vision but it is not known whether they play a role in circadian regulation. A subset of retinal ganglion cells with direct projections to the suprachiasmatic nucleus (SCN) are at the origin of the retinohypothalamic tract that transmits the light signal to the master circadian clock in the SCN. However, the ganglion cells are not known to contain rhodopsin or other opsins that may function as photoreceptors. We have found that the two blue-light photoreceptors, cryptochromes 1 and 2 (CRY1 and CRY2), recently discovered in mammals are specifically expressed in the ganglion cell and inner nuclear layers of the mouse retina. In addition, CRY1 is expressed at high level in the SCN and oscillates in this tissue in a circadian manner. These data, in conjunction with the established role of CRY2 in photoperiodism in plants, lead us to propose that mammals have a vitamin A-based photopigment (opsin) for vision and a vitamin B2-based pigment (cryptochrome) for entrainment of the circadian clock.

X-ray absorption study of the ferromagnetic Cu moment at the YBa_(2)Cu_(3)O_(7)/La_(2/3)Ca_(1/3)MnO_(3) interface and variation of its exchange interaction with the Mn moment

With x-ray absorption spectroscopy and polarized neutron reflectometry we studied how the magnetic proximity effect at the interface between the cuprate high-TC superconductor YBa_(2)Cu_(3)O_(7) (YBCO) and the ferromagnet La_(2/3)Ca_(1/3)MnO_(3) (LCMO) is related to the electronic and magnetic properties of the LCMO layers. In particular, we explored how the magnitude of the ferromagnetic Cu moment on the YBCO side depends on the strength of the antiferromagnetic (AF) exchange coupling with the Mn moment on the LCMO side. We found that the Cu moment remains sizable if the AF coupling with the Mn moments is strongly reduced or even entirely suppressed. The ferromagnetic order of the Cu moments thus seems to be intrinsic to the interfacial CuO_(2) planes and related to a weakly ferromagnetic intraplanar exchange interaction. The latter is discussed in terms of the partial occupation of the Cu 3d_(3z^(2)−r^(2)) orbitals, which occurs in the context of the so-called orbital reconstruction of the interfacial Cu ions.

Setting the Scene: Assessing Opportunities and Threats of the European Neighbourhood

Opinions diverge to what extent the European Neighbourhood Policy has made progress towards achieving its aims, which are – as stated in the Lisbon treaty – to “establish an area of prosperity and good neighbourhoudliness, founded on EU-values”. Today it is necessary to re-think the ENP: What can the ENP achieve with its instruments and what shall it achieve? In which fields do the neighbours have specific expectations towards the ENP? And how are these expectations paralleled by what the European Union is disposed to offer?

Position papers from the Third National Injury Control Conference : "setting the national agenda for injury control in the 1990s" : April 22-25, 1991, Denver, Colorado.

Mode of access: Internet.

The poetic and dramatic works of Robert Browning.

Half-title; each volume has special t.-p.

A guide-book to the poetic and dramatic works of Robert Browning,

"The best things said of Browning": p. [ix]-xiv.

A phrase book from the poetic and dramatic works of Robert Browning,

Mode of access: Internet.

Latin prosody made easy : The 4th ed. with the poetic treatise of Terentianus Maurus, De metics /

Mode of access: Internet.

The poetic works of the Reverend William Smith, D.D., late Dean of Chester:

Contemporary tree calf binding.

The Poetic wreath; consisting of select passages from the works of English poets from Chaucer to Wordsworth, alphabetically arranged ...

Mode of access: Internet.

The poetic and dramatic works of Robert Browning.

[I] Pauline: Paracelsus: Strafford: Sordello: Pippa passes: King Victor and King Charles.--[II] Dramatic lyrics: The return of the Druses: A blot in the 'scuteheon: Colombe's birthday: Dramatic romances: A soul's tragedy: Luria.--[III] The ring and the book.--[IV] Christmas-eve and Easter day: Men and women: In a balcony: Dramatis peronae: Balaustion's adventure: Prince Hohenstiel-Schwangau: Fifine at the fair.--[V] Red cotton night-cap country: Aristophanes' apology: The inn album: Pacchiarotto and how he worked in distemper, and other poems.--[VI] The Agamemmon of æschylus: La Saisiaz: The two poets of Croisic: Dramatic idyls: Jocoseria: Ferishtah's fancies and parleyings.--[VII] A solando.

The poetic and dramatic works of Robert Browning.

Half-title; each vol. has special t. p.