Advances in Signal Processing for Maritime Applications

n/

White sharks exploit the sun during predatory approaches

There is no conclusive evidence of any nonhuman animal using the sun as part of its predation strategy. Here, we show that the world\u27s largest predatory fish-the white shark (Carcharodon carcharias)-exploits the sun when approaching baits by positioning the sun directly behind them. On sunny days, sharks reversed their direction of approach along an east-west axis from morning to afternoon but had uniformly distributed approach directions during overcast conditions. These results show that white sharks have sufficient behavioral flexibility to exploit fluctuating environmental features when predating. This sun-tracking predation strategy has a number of potential functional roles, including improvement of prey detection, avoidance of retinal overstimulation, and predator concealment

Determination of Interaction Potentials in Freeway Traffic from Steady-State Statistics

Many-particle simulations of vehicle interactions have been quite successful in the qualitative reproduction of observed traffic patterns. However, the assumed interactions could not be measured, as human interactions are hard to quantify compared to interactions in physical and chemical systems. We show that progress can be made by generalizing a method from equilibrium statistical physics we learned from random matrix theory. It allows one to determine the interaction potential via distributions of the netto distances s of vehicles. Assuming power-law interactions, we find that driver behavior can be approximated by a forwardly directed 1/s potential in congested traffic, while interactions in free traffic are characterized by an exponent of approximately 4. This is relevant for traffic simulations and the assessment of telematic systems.Comment: For related work see http://www.helbing.or

Decomposition and nutrient release of leguminous plants in coffee agroforestry systems.

Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and(lignin+polyphenol)/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD), the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA), there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1). Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants

Origins of the Highly Ionized Gas along the Line of Sight towards HD 116852

We present Hubble Space Telescope Imaging Spectrograph (HST/STIS) and Far Ultraviolet Spectroscopic Explorer (FUSE) observations of high ion interstellar absorption along the sight line to HD 116852. At a distance of 4.8 kpc, HD 116852 is an O9 III star lying in the low Galactic halo, -1.3 kpc from the plane of the Galaxy in the direction l = 304.9, b = -16.1. The STIS E140H grating observations provide high-resolution (FWHM = 2.7 km/s) spectra of the resonance doublets of Si IV, C IV, and N V. These data are complemented by medium-resolution (FWHM = 20 km/s) FUSE spectra of O VI. We find evidence for three distinct types of highly ionized gas present in the data. First, two narrow absorption components are resolved in the Si IV and C IV profiles, at approximate LSR velocities of -36 and -10 km/s. These narrow components appear to be produced in gas associated with the Norma and Sagittarius spiral arms, at approximate z-distances of -1.0 and -0.5 kpc, respectively. Second, we detect an intermediate-width component in C IV and Si IV, at 17 km/s, which we propose could arise at the conductive interface at the boundary between a low column density neutral or weakly ionized cloud and the surrounding hot medium. Finally, a broad collisionally ionized component of gas responsible for producing the smooth N V and O VI profiles is observed; such absorption is also present to a lesser degree in the profiles of Si IV and C IV. The broad O VI absorption is observed at a velocity displaced from the broad C IV component by almost 20 km/s, an amount large enough to suggest that the two ions may not co-exist in the same physical location.Comment: 39 pages, 6 figures; accepted for publication in January 10, 2003 edition of The Astrophysical Journa

The 11-year long-term follow-up study from the randomized BENEFIT CIS trial

L

Erotic fantasy, spirituality and Song of Songs

Fantasy plays an essential role in sexual activities. This article investigates (erotic) fantasy from a literary text perspective according to Song of Songs in the Christian Bible. The Song, according to many commentaries, starts with a reference to sex in Canticle 1:2, ‘Let him kiss me with the kisses of his mouth! For your love is better than wine’. Although the word sex is not mentioned in the Song, it is referred to and implied a number of times in the deep structure of the text. The fantasies of this most beautiful woman (beauty, a secondary motif in the Song that is complementary to the main theme of love) are part of the rhetoric of the poet (probably a woman) to convince the reader about the enjoyment and beauty of erotic love. These could most likely stimulate erotic fantasies when reading the text. Part of the poet’s rhetoric is the way in which she describes this most beautiful woman and her most attractive lover using metaphors, allusions, symbols and similes to evoke all sorts of imaginations and fantasies in the mind of the reader to complement the erotic fantasies of the reader. The investigation of the composition and ‘lived experiences’ (spiritualities) of erotic fantasies is approached from the perceptions of how the entanglement of the reader in the text augments fantasies, how the dynamic interaction between the text of Song of Songs and the reader involves the reader in the fantasies and spiritualities of the protagonists and the poet, how the lived experiences of the composed images and erotic fantasies in the text of the Song grip and involve the reader in the text and finally how the use or application of human senses in fantasies can intensify the lived experiences of fantasies. This research points out how God’s love and concern for his creatures are present as revealed in the relationship between two lovers. His love and concern are clearly visible in the enjoyment and pleasure given by God to humans in his creation which the lovers find in each other.Christian Spirituality, Church History and Missiolog

Eosinophilic gastroenteritis in a young girl – long term remission under Montelukast

BACKGROUND: Eosinophilic gastrointestinal disorders are an emerging disease entity characterized by eosinophilic infiltration of the intestinal wall. Oral steroids can be still considered as first line treatment. Unfortunately relapses are quite common. Usually long term low-dose prednisone or immunosuppressive therapy is required, which is especially problematic in young patients. Thus a reliable steroid sparing agent with low side effects suitable for long term use is needed. There are strong hints to a similar pathophysiology of eosinophilic gastrointestinal disorders to that of asthma. Indeed leukotriene D4 plays an important role in the recruitment of eosinophils into the intestinal tissue causing damage. This patho-mechanism provides the rationale for the treatment with a leukotriene D4 receptor antagonist. Recently there have been first reports about successful short term use of Montelukast in eosinophilic gastrointestinal disorders. CASE PRESENTATION: We report the case of a 17 year old girl with a long history of severe abdominal complaints leading to several hospitalizations in the past. Mimicking the picture of an intestinal tuberculosis she received an anti mycobacterial treatment without any success. Marked eosinophilia in blood, ascites and tissue samples of the intestinal tract finally lead to the diagnosis eosinophilic gastroenteritis. Tapering off prednisone caused another severe episode of abdominal pain. At that point leukotriene antagonist Montelukast was started at a dose of 10 mg once daily. Steroids could be tapered off completely within six weeks. The patient has been free of symptoms for over two years by now. Routine examinations, blood tests and endoscopy have rendered regular results. So far no side effects were noted. CONCLUSION: Here report about successful long term remission of eosinophilic gastroenteritis under Montelukast. Further randomized control trials are required to asses the full benefits of Montelukast therapy in the whole spectrum of eosinophilic gastrointestinal disorders

Lack of association between right-to-left shunt and cerebral ischemia after adjustment for gender and age

<p>Abstract</p> <p>Introduction</p> <p>A number of studies has addressed the possible association between patent foramen ovale (PFO) and stroke. However, the role of PFO in the pathogenesis of cerebral ischemia has remained controversial and most studies did not analyze patient subgroups stratified for gender, age and origin of stroke.</p> <p>Methods</p> <p>To address the role of PFO for the occurrence of cerebral ischemia, we investigated the prevalence of right-to-left shunt in a large group of patients with acute stroke or TIA. 763 consecutive patients admitted to our hospital with cerebral ischemia were analyzed. All patients were screened for the presence of PFO by contrast-enhanced transcranial Doppler sonography at rest and during Valsalva maneuver. Subgroup analyses were performed in patients stratified for gender, age and origin of stroke.</p> <p>Results</p> <p>A right-to-left shunt was detected in 140 (28%) male and in 114 (42%) female patients during Valsalva maneuver, and in 66 (13%) and 44 (16%) at rest respectively. Patients with right-to-left shunt were younger than those without (<it>P </it>< 0.001). PFO was associated with stroke of unknown origin in male (<it>P </it>= 0.001) but not female patients (<it>P </it>> 0.05). After adjusting for age no significant association between PFO and stroke of unknown origin was found in either group.</p> <p>Conclusion</p> <p>Our findings argue against paradoxical embolization as a major cause of cerebral ischemia in patients with right-to-left shunt. Our data demonstrate substantial gender-and age-related differences that should be taken into account in future studies.</p