Quantum Models for Psychological Measurements: An Unsolved Problem

There has been a strong recent interest in applying quantum theory (QT) outside physics, including in cognitive science. We analyze the applicability of QT to two basic properties in opinion polling. The first property (response replicability) is that, for a large class of questions, a response to a given question is expected to be repeated if the question is posed again, irrespective of whether another question is asked and answered in between. The second property (question order effect) is that the response probabilities frequently depend on the order in which the questions are asked. Whenever these two properties occur together, it poses a problem for QT. The conventional QT with Hermitian operators can handle response replicability, but only in the way incompatible with the question order effect. In the generalization of QT known as theory of positive-operator-valued measures (POVMs), in order to account for response replicability, the POVMs involved must be conventional operators. Although these problems are not unique to QT and also challenge conventional cognitive theories, they stand out as important unresolved problems for the application of QT to cognition. Either some new principles are needed to determine the bounds of applicability of QT to cognition, or quantum formalisms more general than POVMs are needed.     

Ageing,Neuronal Connectivity and Brain Disorders: An Unsolved Ripple Effect

Cognitive decline associated with ageing and age-related disorders emerges as one of the greatest health challenges in the next decades. To date, the molecular mechanisms underlying the onset of neuronal physiological changes in the central nervous system remain unclear. Functional MRI and PET studies have indicated the decline in working memory performance in older adults. Similarly, age-related disorders, such as Alzheimer’s disease, are associated with changes in the prefontral cortex and related neural circuitry, which underlines the decline of integrative function between different brain regions. This is mainly attributed to the loss of synaptic connectivity, which is a feature commonly observed in neurodegenerative disorders. In humans, the morphological and functional changes in neurons, such as reduction of spine numbers and synaptic dysfunction, precede the first signs of cognitive decline and likely contribute to pathology progression. Thus, a new scenario emerges in which apparently unrelated diseases present common features, such as the remodelling of neuronal circuitries promoted by ageing. For many years, ageing was considered a process of slow deterioration triggered by accidental environmental factors. Conversely, it is now evident that ageing is a biological process tightly controlled by evolutionary highly conserved signalling pathways. Importantly, genetic mutations that enhance longevity significantly delay the loss of synaptic connectivity and, therefore, the onset of age-related brain disorders. Accordingly, tweaking ageing might be an attractive approach to prevent cognitive decline caused by age-related synaptic dysfunction.     

A New Species of Freshwater Tardigrades from Disko Island (Greenland) Increases an Unsolved Paradox in Tardigrade Systematics

During the “Workshop on Arctic tardigrades” at the Danish Arctic Station (Qeqertarsuaq, Disko Island, Greenland) an undescribed species of Dactylobiotus was found in freshwater sediments of the Isunngua spring. We have the honour and pleasure to describe this new taxon that we dedicate to all participants of that symposium, naming the species Dactylobiotus octavi sp. n. The animals appear similar to Dactylobiotus dispar and Dactylobiotus haplonyx with the presence of a very short secondary branch in the claws of the first three pairs of legs, but they differ from these species in the size of claw and buccal tube width. This new species also has peculiar ornamented eggs. The eggshell consists of bowl-like processes, each one surrounded by a band of fine pores. A morphological parsimony analysis to identify phylogenetic relationships among D. octavi sp. n. and the other Dactylobiotus species was performed, obtaining inconclusive results. The discovery of this new species increases an unsolved paradox in tardigrade systematics related to the presence of closely related species which share a very similar morphology of the animals but clearly differ in their egg morphology, while, conversely, there are species belonging to different evolutionary lines that have similar eggs, but very different adult morphology. The finding of D. octavi sp. n. increases the already high number of species found in Disko Island and once again underlines the importance of tardigrades in the biodiversity of the Arctic area.     

海南岛爬行动物的八个月调查

1964年3至11月,作者受原四川医学院院长、已故刘承钊学部委员(院士)的派遣,率领一个小组到海南岛进行为期八个月的两栖爬行动物调查.当时海南岛隶属广东省,设海南行政公署管辖,该署卫生处派工作人员萧汉绮同志全程陪同调查.按照分工,调查结果的两栖动物部分已由刘承钊、胡淑琴等发表于<动物学报>1973年19卷4期; 爬行动物部分则仅先后发表了2个新种和1个中国新纪录种(<动物学报>1975年21卷4期)和另1个新种(Asiatic Herpetological Research, 1997年第7卷).该次采集共得爬行动物标本1909号,计76种,分隶56属16科2目.本文报道该次采集的爬行动物,其中大部分物种的部分标本在野外曾进行长度和体重的测量,文中一并加以报道.目前发表此文,谨以之奉献给组织和领导此次调查的刘承钊院士和胡淑琴教授,和自始至终参加八个月调查工作的王宜生先生,他们均已先后逝世.     

Unsolved motility looking for answer

A rod-like axostyle complex turns the anterior end of a termite flagellate, including the plasma membrane, continually in the same direction relative to the rest of the cell at speeds up to approximately 1 Hz. This motility provides direct visual evidence for the fluid nature of cell membranes. Torque is generated along the length of the axostyle complex by an unknown mechanism. Here I describe findings not published before and promising experiments that may help to solve this remarkable motility.