First report of Candidatus phytoplasma mali in Greece and correlation with small apple fruit disorder occurring in the orchards of the pelion mountain

The apple producing area of the Pelion Mountain suffers the last six years from the extensive phenomenon of small fruiting. Small fruit may appear in few or even all trees of the orchards as well as on few or several branches of each tree. Recovery phenomena and reappearance of the symptoms were observed. Malus xdomestica 'Starking Delicious', widely cultivated at Pelion Mountain, showed high susceptibility. Preliminary studies on the aetiology of this phenomenon were focused to physiological abnormalities in small fruits and to pathogen detection. In small fruits, a high concentration of Mn is observed. The basic colour is not modified, but anthocyanids in the phloem are reduced. Soluble solids and dry mass is decreased, but no difference in pH and acidity is measured. Small apples also show inability in reaching maturation, as they are harder and remain on the tree for many weeks after harvest. Injections with oxytetracycline in a small number of trees were carried out; in the next year a remission of the symptoms in 60% of cases was observed. In September 2005, PCR diagnostic tests for Candidatus Phytoplasma mali in symptomatic trees were performed revealing high presence of the pathogen in the region; out of the 131 trees tested, 43 were positive. The high detection rate of Candidatus Phytoplasma mali in symptomatic trees reveals the high correlation of the presence of the pathogen with small fruit disorder

Encoding, Rehearsal, and Recall in Signers and Speakers: Shared Network but Differential Engagement

Short-term memory (STM), or the ability to hold verbal information in mind for a few seconds, is known to rely on the integrity of a frontoparietal network of areas. Here, we used functional magnetic resonance imaging to ask whether a similar network is engaged when verbal information is conveyed through a visuospatial language, American Sign Language, rather than speech. Deaf native signers and hearing native English speakers performed a verbal recall task, where they had to first encode a list of letters in memory, maintain it for a few seconds, and finally recall it in the order presented. The frontoparietal network described to mediate STM in speakers was also observed in signers, with its recruitment appearing independent of the modality of the language. This finding supports the view that signed and spoken STM rely on similar mechanisms. However, deaf signers and hearing speakers differentially engaged key structures of the frontoparietal network as the stages of STM unfold. In particular, deaf signers relied to a greater extent than hearing speakers on passive memory storage areas during encoding and maintenance, but on executive process areas during recall. This work opens new avenues for understanding similarities and differences in STM performance in signers and speakers

Short-term memory span: insights from sign language

Short-term memory (STM), or the ability to hold information in mind for a few seconds, is thought to be limited in its capacity to about 7 +/- 2 items. Notably, the average STM capacity when using American Sign Language (ASL) rather than English is only 5 +/- 1 items. Here we show that, contrary to previous interpretations, this difference cannot be attributed to phonological factors, item duration or reduced memory abilities in deaf people. We also show that, despite this difference in STM span, hearing speakers and deaf ASL users have comparable working memory resources during language use, indicating similar abilities to maintain and manipulate linguistic information. The shorter STM span in ASL users therefore confirms the view that the spoken span of 7 +/- 2 is an exception, probably owing to the reliance of speakers on auditory-based rather than visually based representations in linguistic STM, and calls for adjustments in the norms used with deaf individuals