Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor

A change in 'symmetry' is often observed when matter undergoes a phase transition-the symmetry is said to be spontaneously broken. The transition made by underdoped high-transition-temperature (high-Tc) superconductors is unusual, in that it is not a mean-field transition as seen in other superconductors. Rather, there is a region in the phase diagram above the superconducting transition temperature Tc (where phase coherence and superconductivity begin) but below a characteristic temperature T* where a 'pseudogap' appears in the spectrum of electronic excitations. It is therefore important to establish if T* is just a cross-over temperature arising from fluctuations in the order parameter that will establish superconductivity at Tc (refs 3, 4), or if it marks a phase transition where symmetry is spontaneously broken. Here we report that, for a material in the pseudogap state, left-circularly polarized photons give a different photocurrent from right-circularly polarized photons. This shows that time-reversal symmetry is spontaneously broken below T*, which therefore corresponds to a phase transition.     

Lack of mutagenicity of irradiated glucose in Salmonella typhimurium using host-mediated assay

Experiments were conducted to study the ability of irradiated glucose to induce reverse mutations in S. typhimurium by host-mediated assay. The results revealed no significant increase in the frequency of reverse mutations compared to controls.     

Comparison of native and microwave irradiated DNA

Chemical changes induced in the testicular DNA of irradiated Swiss male mice are described. Parameters quantified were hyperchromocity and melting temperature. The data supports the possibility that microwave causes strand separation.     

Increased formation of asparagine in ‘Carica-curl’ virus infected leaves

Zusammenfassung Mit Hilfe der Papierchromatographie wurden lösliche und unlösliche Proteine in gesunden und durch «Carica-Curl»-Virus erkrankten Blättern von Carica-Papaya bestimmt. In kranken Blättern nehmen die unlöslichen Proteine ab, der Gehalt an Asparagin,-Alanin +-Aminobuttersäure zu, was wohl auf eine Änderung des Eiweißstoffwechsels der infizierten Blätter unter dem Einfluss des Virus zurückgeführt werden darf.     

具有三个CM公共值的亚纯函数的唯一性

本文指出仪洪勋和Brosch G在具有三个判别的CM公共值的亚纯函数的唯一性定理中,关于对数函数的导数是整函数的推导,可以用指数函数求导的方法来证明.改进了仪洪勋和Brosch G关于重值与唯一性定理.     

Isatin-3-anils as excystment and cysticidal agents againstSchizopyrenus russelli

Summary A series of isatin-3-anils (with or without a N-piperidino/morpholinomethyl substituent) have been screened for their cysticidal activity againstSchizopyrenus russelli. Their ability to cause excystment has also been studied.     

Rhythmic variations in the activities of aldolase and isocitrate dehydrogenase in the heart muscle of the scorpion,Heterometrus fulvipes (C. Koch)

Summary The activity levels of aldolase and isocitrate dehydrogenase were assayed in the heart muscle of scorpion,Heterometrus fulvipes. The enzyme activities showed a circadian rhythmicity with a peak value at 20.00 h in the heart muscle.     

Mitosis in the haemocytes ofSarcophaga ruficornis (diptera)

Summary Among the haemocytes ofSarcophaga ruficornis, only the prohaemocytes divide. Injection of phytohaemagglutinin-P induces 100% prohaemocytes to undergo mitosis but does not induce mitosis in other cells. Mitotic stages other than the prophase are apparently very short lived.Acknowledgment. We express our gratitude to the State Council of Scientific and Industrial Research, U.P. for the grant of financial assistance to U.S.S.