Sperm whale long-range echolocation sounds revealed by ANTARES, a deep-sea neutrino telescope

Despite dedicated research has been carried out to adequately map the distribution of the sperm whale in the Mediterranean Sea, unlike other regions of the world, the species population status is still presently uncertain. The analysis of two years of continuous acoustic data provided by the ANTARES neutrino telescope revealed the year-round presence of sperm whales in the Ligurian Sea, probably associated with the availability of cephalopods in the region. The presence of the Ligurian Sea sperm whales was demonstrated through the real-time analysis of audio data streamed from a cabled-to-shore deep-sea observatory that allowed the hourly tracking of their long-range echolocation behaviour on the Internet. Interestingly, the same acoustic analysis indicated that the occurrence of surface shipping noise would apparently not condition the foraging behaviour of the sperm whale in the area, since shipping noise was almost always present when sperm whales were acoustically detected. The continuous presence of the sperm whale in the region confirms the ecological value of the Ligurian sea and the importance of ANTARES to help monitoring its ecosystems.

Significance of isomeric reaction intermediates in the hydrogenolysis of glycerol to 1,2-propanediol with Cu-based catalysts

The 2,3-enediol isomer was identified as the most favorable isomer to give 1,2-PDO.

Reintroducing photosynthesis

This article reports on conceptual difficulties related to photosynthesis and respiratory metabolism of a Plant Physiology course for undergraduate students that could hinder their better learning of metabolic processes. A survey of results obtained in this area during the last 10 academic years was performed, as well as a specific test, aimed to find out prior conceptual schemes in the students. The test included only basic, general questions on plant metabolism, and was passed on the first day of the course. Scores obtained by different groups of students were compared. Survey of students' performance in previous years shows that questions on plant metabolism result in significantly lower number of correct answers than for the rest of questions, despite reiteration of its teaching in prior educational levels. Some areas such as respiration or light-independent reactions of photosynthesis, as well as concepts and terminology related to electrochemistry, seem to be particularly difficult. The specific test also shows differences among the different groups of students included in this investigation. Our results point out that reiteration of a particular subject in the curricula at different educational levels does not result in a coherent enough conceptual scheme in the students. To help students in this task, it is recommended to teach the general processes also in advanced courses in which these processes are taught in great detail. In this way, settlement of the appropriate conceptual scheme may be reinforced.

Overall brain connectivity maps show cortico-subcortical abnormalities in schizophrenia

Abnormal interactions between areas of the brain have been pointed as possible causes for schizophrenia. However, the nature of these disturbances and the anatomical location of the regions involved are still unclear. Here, we describe a method to estimate maps of net levels of connectivity in the resting brain, and we apply it to look for differential patterns of connectivity in schizophrenia. This method uses partial coherences as a basic measure of covariability, and it minimises the effect of major physiological noise. When overall (net) connectivity maps of a sample of 40 patients with schizophrenia were compared with the maps from a matched sample of 40 controls, a single area of abnormality was found. It is an area of patient hyper-connectivity and is located frontally, in medial and orbital structures, clearly overlapping the anterior node of the default mode network (DMN). When this area is used as a region of interest in a second-level analysis, it shows functional hyper-connections with several cortical and subcortical structures. Interestingly, the most significant abnormality is found with the caudate, which has a bilateral pattern of abnormality, pointing to a possible DMN-striatum deviant relation in schizophrenia. However, hyper-connectivity observed with other regions (right hippocampus and amygdala, and other cortical structures) suggests a more pervasive alteration of brain connectivity in this disease.

Failure to deactivate in the prefrontal cortex in schizophrenia: dysfunction of the default mode network?

BACKGROUND

Functional imaging studies using working memory tasks have documented both prefrontal cortex (PFC) hypo- and hyperactivation in schizophrenia. However, these studies have often failed to consider the potential role of task-related deactivation.

METHOD

Thirty-two patients with chronic schizophrenia and 32 age- and sex-matched normal controls underwent functional magnetic resonance imaging (fMRI) scanning while performing baseline, 1-back and 2-back versions of the n-back task. Linear models were used to obtain maps of activations and deactivations in the groups.

RESULTS

The controls showed activation in the expected frontal regions. There were also clusters of deactivation, particularly in the anterior cingulate/ventromedial PFC and the posterior cingulate cortex/precuneus. Compared to the controls, the schizophrenic patients showed reduced activation in the right dorsolateral prefrontal cortex (DLPFC) and other frontal areas. There was also an area in the anterior cingulate/ventromedial PFC where the patients showed apparently greater activation than the controls. This represented a failure of deactivation in the schizophrenic patients. Failure to activate was a function of the patients' impaired performance on the n-back task, whereas the failure to deactivate was less performance dependent.

CONCLUSIONS

Patients with schizophrenia show both failure to activate and failure to deactivate during performance of a working memory task. The area of failure of deactivation is in the anterior prefrontal/anterior cingulate cortex and corresponds to one of the two midline components of the 'default mode network' implicated in functions related to maintaining one's sense of self.

[One year prevalence of mental disorders comorbidity and associated socio-demographic risk factors in the general population of Spain. Results of the ESEMeD-Spain study]

INTRODUCTION

Comorbidity among mental disorders in the general population is common, affecting more than the 50 % of individuals with a lifetime mental disorder. In Spain, there are no data describing it or its associated risk factors.

METHOD

The ESEMeD-Spain study is an epidemiological study assessing mental disorders in a sample of 5,473 individuals from the general population of Spain aged 18 years or older. The aims of the present study were to evaluate the frequency of mental disorders comorbidity in Spain (assessed with the Composite International Diagnostic Interview: CIDI 3.0) and associated sociodemographic risk factors. Response rate was 78.6%.

RESULTS

Mood disorders showed the highest comorbidity frequency. Analysing specific disorders, generalized anxiety disorder, dysthymic and panic disorders showed the highest comorbidity percentages. Female gender, ages above 24 years old and being previously married were found to be risk factors associated to the presence of comorbid mood and anxiety disorders.

CONCLUSIONS

As it has been suggested for other European countries and for the United States, in the general population of Spain mental disorders, specially mood disorders, are frequently comorbid. When treating mental disorders, comorbidity should be taken into account.

A simple view of the brain through a frequency-specific functional connectivity measure

Here we develop a measure of functional connectivity describing the degree of covariability between a brain region and the rest of the brain. This measure is based on previous formulas for the mutual information (MI) between clusters of regions in the frequency domain. Under the current scenario, the MI can be given as a simple monotonous function of the multiple coherence and it leads to an easy visual representation of connectivity patterns. Computationally efficient formulas, adequate for short time series, are presented and applied to functional magnetic resonance imaging (fMRI) data measured in subjects (N=34) performing a working memory task or being at rest. While resting state coherence in high (0.17-0.25 Hz) and middle (0.08-0.17 Hz) frequency intervals is bilaterally salient in several limbic and temporal areas including the insula, the amygdala, and the primary auditory cortex, low frequencies (<0.08 Hz) have greatest connectivity in frontal structures. Results from the comparison between resting and N-back conditions show enhanced low frequency coherence in many of the areas previously reported in standard fMRI activation studies of working memory, but task related reductions in high frequency connectivity are also found in regions of the default mode network. Finally, potentially confounding effects of head movement and regional volume on MI are identified and addressed.

[Intracranial purulent collections. Review of 34 surgically treated cases in 12 years (1989-2000)]

We made a revision of 34 cases of intracerebral supurations (31 brain abscesses and 3 subdural empyemas) treated at our department of neurosurgery of "Mutua de Terrassa" during the period of 1989-2000. Treatment used was tapping of the abscess and aspiration in 28 cases and craneotomy and resection in only two cases. Three subdural empyemas were treated with burr-holes and aspiration. Results were evaluated using the Glasgow Outcome Scale at 6 months after discharge, resulting in 7 deaths (20.6%), 17 fully recovered patients (50%) and 10 with minor deficits (29.4%). Glasgow Coma Score at admission and the age were the unique variables significantly correlated with the final outcome. After analyzing the cost of treatment in our patients we suggest using antibiotic ambulatory treatment when the disease shows an adequate clinical and radiological response, thus permitting to shorten the usually long period of hospitalization of patients with intracerebral supurative diseases.

Towards a method for automated classification of 1H MRS spectra from brain tumours

Recent studies have shown that MRS can substantially improve the non-invasive categorization of human brain tumours. However, in order for MRS to be used routinely by clinicians, it will be necessary to develop reliable automated classification methods that can be fully validated. This paper is in two parts: the first part reviews the progress that has been made towards this goal, together with the problems that are involved in the design of automated methods to process and classify the spectra. The second part describes the development of a simple prototype system for classifying 1H single voxel spectra, obtained at an echo time (TE) of 135 ms, of the four most common types of brain tumour (meningioma (MM), astrocytic (AST), oligodendroglioma (OD) and metastasis (ME)) and cysts. This system was developed in two stages: firstly, an initial database of spectra was used to develop a prototype classifier, based on a linear discriminant analysis (LDA) of selected data points. Secondly, this classifier was tested on an independent test set of 15 newly acquired spectra, and the system was refined on the basis of these results. The system correctly classified all the non-astrocytic tumours. However, the results for the the astrocytic group were poorer (between 55 and 100%, depending on the binary comparison). Approximately 50% of high grade astrocytoma (glioblastoma) spectra in our data base showed very little lipid signal, which may account for the poorer results for this class. Consequently, for the refined system, the astrocytomas were subdivided into two subgroups for comparison against other tumour classes: those with high lipid content and those without.

Identification of two processed psuedogenes of the human Tom20 gene

The open reading frame (ORF) of the human Tom20 gene (hTom20) was amplified by PCR from a HeLa cDNA library using primers based on the sequence of HUMRSC145 and cloned into a pET15b vector. Amplification of human genomic DNA using these primers yielded a DNA fragment of the same size as that of the ORF of hTom20 cDNA. Sequencing of this fragment revealed that: (1) it has the same number of base pairs as the ORF of hTom20 cDNA (438 bp); and (2) the two sequences differ by 14 single base pair substitutions (97% similarity) causing eight changes in the amino acid sequence and two premature stop codons. Further amplification of human genomic DNA adaptor-ligated libraries using primers based on HUMRSC145 revealed three different sequence-related genomic regions; one corresponding to the fragment referred above, another corresponding to the hTom20 gene, and a third fragment of which the sequence differs from the ORF of hTom20 cDNA by only 22 base pair substitutions and a deletion of 4 bp. We conclude that, in addition to the hTom20 gene, there are two genomic DNA sequences (psi1Tom20 and psi2Tom20) that are processed pseudogenes of hTom20. Aspects concerning their evolutionary origin are discussed.

Force field calculations on five membered ring aminoxyl radicals

Two force fields (MM2 and Genmol) have been applied to the modeling of five membered ring aminoxyl radicals. For the six molecules which were investigated the geometry of the conformation with the lowest strain energy was in very good agreement with the X-ray geometry. However owing to the high flexibility of five membered rings other conformations were shown to have a strain energy close to the energy minimum.

Intracranial arachnoid cysts in adults

Twenty-two cases of intracranial arachnoid cysts in adult patients have been studied and treated surgically. The authors analysed the correlation between the size and the location of the cysts and their clinical manifestations. It seems clear that the symptomatology and the problems of intracranial arachnoid cysts in the adult are quite different from those occurring with infants. The majority of our cases have been diagnosed by CT and NMR, and have been treated by open excision of the cystic membranes with the establishment of a wide communication with the basal cisterns or the subarachnoid space. With this technique the results have been very gratifying, while in cases managed with shunts the morbidity has been high.

Pyocephalus of the newborn child

3 cases of pyocephalus (ventricular empyema) in newborn children are described and 16 cases from the literature are analyzed. Half of the previously published cases of pyocephalus are secondary to cerebral abscesses. Neuroradiological findings and especially the necroscopic study of a case demonstrated the existence of membranous blockages inside the ventricles which may make the circulation of CSF impossible. Our treatment of choice consists of repeated punctures and evacuations of purulent content and topic as well as parenteral administration of antibiotics. Further CSF derivative measures are almost always necessary. By these means, we believe the high mortality of these cases could be lowered.

Weyl's Theory of Glaciation Supported by Isotopic Study of Norwegian Core K 11

Oxygen-18 analyses of pelagic and benthic foraminifera from core K 11 indicate that during the last glaciation Norwegian Sea bottom waters were warmer than in modern times and had the same physical parameters (temperature, oxygen isotope ratio, and salinity) as the North Atlantic deep water. This result indicates that the glacial Norwegian Sea was not a sink for dense surface water, as it is now, and that during glacial times North Atlantic deep water invaded the deep Norwegian basin.