When is now? Perception of simultaneity.

We address the following question: Is there a difference (D) between the amount of time for auditory and visual stimuli to be perceived? On each of 1000 trials, observers were presented with a light-sound pair, separated by a stimulus onset asynchrony (SOA) between -250 ms (sound first) and +250 ms. Observers indicated if the light-sound pair came on simultaneously by pressing one of two (yes or no) keys. The SOA most likely to yield affirmative responses was defined as the point of subjective simultaneity (PSS). PSS values were between -21 ms (i.e. sound 21 ms before light) and +150 ms. Evidence is presented that each PSS is observer specific. In a second experiment, each observer was tested using two observer-stimulus distances. The resultant PSS values are highly correlated (r = 0.954, p = 0.003), suggesting that each observer''s PSS is stable. PSS values were significantly affected by observer-stimulus distance, suggesting that observers do not take account of changes in distance on the resultant difference in arrival times of light and sound. The difference RTd in simple reaction time to single visual and auditory stimuli was also estimated; no evidence that RTd is observer specific or stable was found. The implications of these findings for the perception of multisensory stimuli are discussed.     

Methamphetamine. Stimulant of the 1990s?

During the past several years, the use of a smokable form of methamphetamine hydrochloride called "ice" has increased rapidly. The heaviest use has occurred on the West Coast and in Hawaii. Many regional emergency departments treat more methamphetamine users than cocaine-intoxicated patients. The ease of synthesis from inexpensive and readily available chemicals makes possible the rampant abuse of a dangerous drug that can produce a euphoria similar to that induced by cocaine. Clinicians should be familiar with the medical effects and treatment of acute methamphetamine toxicity.     

Aberrations of chromosome 3. A marker of T-cell lymphomas?

Aberrations of chromosome occur in different malignancies, but they are more frequent in lymphoproliferative ones than in the others. In this study here four out of five T-zone lymphomas had abnormalities of chromosome 3. This lead to the question of whether aberrations of chromosome 3 might be a marker of T-cell lymphomas. The conclusion which can be drawn from the cases described in the literature, the own unpublished cases, and these four T-zone lymphomas is that abnormalities of chromosome 3 cannot be regarded as a discriminative marker of T-cell derived malignancies. It is suggested that the relationship between chromosome aberrations and type of disease is not necessarily a direct one. One possible model of the genesis of chromosome aberrations in malignant diseases is presented.     

Spectrin-phospholipid interactions. Existence of multiple kinds of binding sites?

The object of this paper is to review briefly the studies on the interactions of erythroid and non-erythroid spectrins with lipids in model and natural membranes. An important progress on the identification of lipid-binding sites has recently been made although many questions remain still unanswered. In particular, our understanding of the physiological role of such interactions is still limited. Another important issue is the occurrence of spectrins in membrane rafts, how they are attached to the raft and what is their function in rafts.     

Phylogenenetic approach of the section Bulbocodii D.C. of Narcissus based on cpDNA. A case of taxonomic inflation?

In this paper, we analyzed the phylogeny of the section Bulbocodii (genus Narcissus; Amarillydaceae) using the matK and trnL-F fragments of cpDNA in order to review the validity of the recognized taxa. Our results indicate that Narcissus obesus should be considered a valid species, and that N. blancoi is a distinct taxon. In addition, seven previously recognized species, N. juressianus, N. subnivalis, N. graellsii, N. conspicuus, N. citrinus, N. nivalis, and N. quintanilhae, should be assigned to an infraspecific rank under N. bulbocodium, as they are not valid species. In addition, we analyzed the distribution of the three morphological characters widely used in the systematics of this section and found that their variation does not agree with the phylogenetic results, rendering these characters limited taxonomical utility. This result suggests that the section Bulbocodii shows high morphological lability, which can explain the proliferation of nominal species.     

Reverse K?nigs-Knorr reaction. Synthesis of beta-D-gluco-thio-cerebroside

The synthesis of 1-thio-beta-D-glucocerebroside by reaction of 1-iodo-3-O-benzoylceramide with 1-mercapto-beta-D-glucopyranose in the presence of sterically hindered amine (DBU) is described.     

Some contributions of I.E. Purkyn? to the visual physiology

In the research of binocular vision J. E. Purkyn? pointed out the role of retinal corresponding areas. He observed binocular interaction of pressure phosphenes elicited in them and the fusion of images projected on the corresponding foveal areas even in eyes with artificial divergency. For the first time he proposed the examination of visual fields (perimetry) in several planes and he also introduced the colour perimetry. Purkyn? analyzed profoundly the different functions of direct (foveal) and indirect (peripheral) vision. In indirect vision he anticipated the modern concept of the useful field of view. Of fundamental importance was Purkyn?'s research of the strategy and different types of ocular movements. In analysis of motion perception, he evolved the hypothesis of "general sense of space" which is very close to modern feed-back conception of "corollary discharge".     

60Ma of legume nodulation. What's new? What's changing?

Current evidence suggests that legumes evolved about 60 million years ago. Genetic material for nodulation was recruited from existing DNA, often following gene duplication. The initial process of infection probably did not involve either root hairs or infection threads. From this initial event, two branched pathways of nodule developmental processes evolved, one involving and one not involving the development of infection threads to 'escort' bacteria to young nodule cells. Extant legumes have a wide range of nodule structures and at least 25% of them do not have infection threads. The latter have uniform infected tissue whereas those that have infection threads have infected cells interspersed with uninfected (interstitial) cells. Each type of nodule may develop indeterminately, with an apical meristem, or show determinate growth. These nodule structures are host determined and are largely congruent with taxonomic position. In addition to variation on the plant side, the last 10 years have seen the recognition of many new types of 'rhizobia', bacteria that can induce nodulation and fix nitrogen. It is not yet possible to fit these into the emerging pattern of nodule evolution.     

Malate. Jack of all trades or master of a few?

The dicarboxylic acid malate has long been thought to play important roles in plant physiology. In addition to being a major photosynthate in C4 and CAM plants and an intermediate of the tricarboxylic acid cycle it has been proposed to play essential roles in pH regulation and important roles in pathogen response, as a component of the root exudates and as a regulatory osmolyte affecting stomatal function. Recent years have seen the cloning and functional analysis of a wide range of enzymes and transporters associated with malate metabolism. Here we attempt to provide a synthesis of research in this field as well as re-evaluating the role of this metabolite in mediating guard cell function.     

Description of Oerskovia gen. n. to Harbor ?rskov's Motile Nocardia

The genus Oerskovia is proposed to harbor actinomycetes forming an extensively branched substrate mycelium which usually breaks up into motile elements. Cell wall preparations contain major amounts of lysine and galactose. Aspartic acid is often present in major amounts. Aerial mycelium is not formed. Gram reaction and catalase production are positive. The type species is Oerskovia turbata comb. n.     

What would T. H. Huxley have made of prion diseases?

T. H. Huxley was “Darwin’s bulldog,” and took the offensive in championing the cause of evolution against skeptical scientists and outraged theologians. As such, he took part in one of the great “paradigm shifts” of biology, at the end of the nineteenth century. Huxley was a rigorous scientist and wrote important articles on scientific method, as well as publishing extensively on a wide range of subjects in natural history. In the second half of the twentieth century, the “prion hypothesis” was put forward to explain the pathogenesis of a curious group of diseases known as the transmissible spongiform encephalopathies. This also involved a “paradigm shift” because the prion hypothesis postulated that biologically relevant information could be enciphered in protein conformation (rather than encoded in nucleic acid base sequences), and could be transmitted from one molecule to another, thereby causing infectious disease. This article examines a few of Huxley’s remarks to speculate on how he might have responded to the scientific debate about prion disease had he lived a century later.     

M?ssbauer investigations of high-spin ferrous heme proteins. I. Cytochrome P-450.

Anaerobically reduced samples of cytochrome P-450 from Pseudomonas putida were studied by M?ssbauer spectroscopy. In the presence of an applied magnetic field the high-spin ferrous heme iron showed an intricate pattern of electric and magnetic hyperfine interactions which could be parametrized successfully in terms of a spin Hamiltonian formalism. The results imply a very low (triclinic) symmetry of the heme iron. The effects of the ligand environment and of spin-orbit coupling result in a large zero-field splitting of the electronic ground state. The electronic ground state. The electric-field gradient tensor is characterized by a large asymmetry parameter, and its principal axes are rotated substantially from the frame that defines the zero-field splitting. This study shows that high-field M?ssbauer spectroscopy provides a unique tool for structural investigations of high-spin ferrous compounds and can substitute, under suitable conditions, for magnetic susceptibility measurements. The present paper focuses on the methodology and data analysis; in the subsequent paper the data obtained for P-450 are compared with new results obtained for hemoglobin, chloroperoxidase, and horseradish peroxidase.     

What about R.A. Fisher's statement of the "too good" data of J.G. Mendel's Pisum paper?

Mendel was accused by Fisher that his observed data, which corresponded to expectations, were too good to be true, and, further, that Mendel, growing only 10 plants per offspring, disregarded in his genotypical analysis the loss of recessives by assuming a ratio of 1:2 instead of 1.1126:1.8874. In contrast, it is proposed here that all chi-square statistics of genetic segregations fall short because the variance of genetic segregations is smaller and not of a binomial type as assumed. Furthermore, this variance and the corresponding chi-square statistics are not homogeneous in different segregation types. Consequently, it is not possible to summarize the different chi-square statistics as Fisher did. It is only in this way that he was able to obtain his unrealistic result (a probability of "seven times in 100,000 cases"). Regarding Fisher's second accusation, it should be taken into account that Mendel selected his 10 plants from offspring with a finite and not an infinite number of entities. Although this number is different from offspring to offspring, the average number is about 30. This means that the loss of recessives must be calculated by using a hypergeometric and not a binomial model as Fisher did. Consequently, the real deviation from the 1:2 ratio can be disregarded.