Identificaci�� de variables d'estat del sistema costaner sensibles a la c��rrega de nutrients

Projecte de recerca elaborat a partir d���una estada a la Napier University, Gran Bretanya, des d���octubre del 2006 a febrer del 2007. Els ecosistemes marins costaners s��n sistemes complexos, tant pel que fa a l���estructura de les comunitats que hi viuen com per la seva din��mica, amb processos que impliquen m��ltiples escales d���espai i de temps. Aquesta complexitat natural s���ha incrementat al llarg de les darreres d��cades com a conseq����ncia directa del creixement urb�� al litoral. L���augment de poblaci�� a les zones costaneres ha comportat no nom��s un augment generalitzat en l���aport de nutrients inorg��nics al mar, sin�� tamb�� una forta intervenci�� sobre la l��nia de costa ���construcci�� de ports, dics- i canvis en el moviment de les masses d���aigua. En aquest context, la interacci�� entre els factors turbul��ncia-nutrients a la zona costanera pot ser clau per a millorar la nostra comprensi�� sobre el funcionament dels sistemes planct��nics i, en darrer terme, per a derivar-ne mesures de gesti��. A difer��ncia de treballs experimentals previs, que adrecen els efectes de la turbul��ncia i/o els nutrients sobre grups espec��fics de pl��ncton, per avaluar la resposta conjunta de la comunitat necessitem par��metres integradors, que relacionin diversos processos i donin una idea general de l���estat i funcionament de l���ecosistema. Durant l���estada de recerca alguns dels algoritmes que es fan servir per la costa escocesa van reformular-se i recalcular-se amb dades de la Mediterr��nia (dades procedents de la badia de Blanes i de la costa de Barcelona). Els resultats mostren una capacitat de resposta molt r��pida del pl��ncton als increments de nutrients, una variabilitat anual marcada (quant a diversitat d���organismes planct��nics) i apunten el f��sfor com a principal limitant del creixement dels organismes en aquesta zona de la Mediterr��nia.

Some Considerations Concerning Regulation and Competition in the Port Sector

The aim of this paper is to discuss the circumstances in which the process of competition between ports takes place in Spain ��� circumstances arising from the way the port system is currently set up and from the regulations governing it. The importance of this matter lies both in the fact that intensified competition between ports is the way to set about boosting the efficiency of the Spanish port sector and in the relevance of this business to the economies of the regions in which the ports are located. It is precisely for this reason that the reform instituted in 1992 aimed to combine balanced development of the national port system with the defence of the interests of autonomous regions. To this end the current regulatory framework provides for the possibility of port authorities drawing up their own competitive strategies, but makes their implementation conditional upon approval of their business plan by the Spanish state port authority. The latter body coordinates the national port system to ensure the guidelines set by the central government authorities are followed in the field of transport. However, the scale of the differences which exist among both the size of facilities and their relevant markets on the one hand, and the financial and economic circumstances of each of them on the other, suggest that each port authority's needs must be very different. Consequently, their competitive strategies must also be very different. It is therefore valid to ask whether coping with this diversity calls for different guidelines to regulate their freedom of action. Key words: Competition, regulation, port sector JEL classification numbers: L1, L5, L9

Impacte ambiental dels iots en els ports de Sitges: an��lisi comparativa

Els ports esportius a nivell catal�� han augmentat considerablement a causa de la creixent afici�� a la navegaci�� i els esports n��utics. L���increment de la demanda d���amarratges al port i la conseq��ent concentraci�� d���iots, ha implicat la necessitat d���un estudi dels seus impactes potencials. El Port Garraf t�� un impacte m��s redu��t degut a que prioritzen les embarcacions de vela, en canvi pel que fa al Port d���Aiguadol�� i Port Ginesta la proporci�� d���embarcacions a motor ��s superior, per tant tindran un consum m��s elevat de combustible. Pel que fa a residus especials, concretament olis, els tres ports tenen un impacte sever per la dif��cil recuperaci�� del medi en cas d���accident, encara que hi ha una bona gesti�� en els ports. Per acabar el Port d���Aiguadol�� ��s el que t�� un consum d���aigua superior. Segons la comparaci�� que s���ha realitzat dels diferents fluxos, es pot concloure que el port Ginesta ��s el m��s sostenible. Gr��cies a la bona gesti�� portu��ria i a la sensibilitzaci�� dels usuaris del port, tot i tenir major superf��cie i m��s quantitat d���embarcacions, aquest port ��s el que t�� menors impactes potencials.

Staffing strategies in SME's: determinants of external recruitment and internal promotion

The purpose of this paper is to examine the determinants of use internal or external labour market to fill a firm vacancy in SME���s taking into account the differences existing among blue and white collar jobs. Following different theories we can identify three main reasons for use internal candidates rather than external ones��� firm specific knowledge, adverse selection problems and motivation���. However, there are others factors that might affect this choice but the last theories don���t take into account. In this paper we try to shed some light on what are these other factors that may affect firm decision to use internal or external labour market. Particularly we analyses the relationship among new technologies, innovation activity and firm location on the staffing strategy. The results shows difference behaviour on the decision to fill a vacancy using internal or external labour markets between manufacturing and service firms, and this decision depends not only on firm internal characteristics, like technological complexity or innovation activity, but also on firm location. The results also support the hypothesis of ports of entry especially in the manufacturing sector.

La festa de la Santantonada a la Todolella (els Ports)

Descripci��, an��lisi i propostes sobre la Santantonada tolellana.

Levels of PSP toxins in bivalves exposed to natural blooms of Alexandrium minutum in Catalan harbours

The development, validation, comparison and evaluation of analytical methods for marine toxins rely on the availability of toxic material. Within the project JACUMAR PSP, our interest is mainly focused on autochthonous bivalve species with the toxic profile of Alexandrium minutum, since this is the principal species involved regionally in PSP outbreaks. Mussels and oysters were exposed during few days in the harbor of Vilanova i la Geltr��, to blooms reaching a maximum A. minutum concentration of 200,000 cells L-1 in 2008, and 40,000 and 800,000 cells L-1, in 2009. Mussels, oysters and clams were exposed to one bloom of 22,000 cells L-1 in the harbor of Cambrils in 2009. In all situations higher toxic levels analyzed by HPLC-FD with postcolumn oxidation were observed in mussels (i.e. 1,200-2,500 ��g eq. STX kg-1) than in oysters (i.e. 60-800 ��g eq. STX kg-1) exposed to the same bloom. Blooms with higher concentrations of A. minutum did not correspond to higher levels of PSP toxins in bivalves. These differences may be explained by differences in A. minutum population dynamics, toxin production or in the physiological state or behaviour of shellfish. These results confirm that mussels concentrate more PSP toxins from A. minutum than oysters and clams.

Electromagnetic radiation initiated by hadronic jets from microquasars in the ISM

Microquasars are potential candidates to produce a non-negligible fraction of the observed galactic cosmic rays. The protons accelerated at the jet termination shock interact with the interstellar medium and may produce detectable fluxes of extended emission at different energy bands: high-energy and very high-energy gamma-rays produced by neutral pion-decay, synchrotron and bremsstrahlung emission in a wide energy range generated by the secondary electrons produced by charged pion-decay. We discuss the association between this scenario and some of the unidentified EGRET sources in the galactic plane.

Exploring the connection between the stellar wind and the non-thermal emission in LS 5039

Context.LS 5039 has been observed with several X-ray instruments so far showing quite steady emission in the long term and no signatures of accretion disk. The source also presents X-ray variability at orbital timescales in flux and photon index. The system harbors an O-type main sequence star with moderate mass-loss. At present, the link between the X-rays and the stellar wind is unclear. Aims.We study the X-ray fluxes, spectra, and absorption properties of LS 5039 at apastron and periastron passages during an epoch of enhanced stellar mass-loss, and the long term evolution of the latter in connection with the X-ray fluxes. Methods.New XMM-Newton observations were performed around periastron and apastron passages in September 2005, when the stellar wind activity was apparently higher. April 2005 Chandra observations on LS 5039 were revisited. Moreover, a compilation of H EW data obtained since 1992, from which the stellar mass-loss evolution can be approximately inferred, was carried out. Results.XMM-Newton observations show higher and harder emission around apastron than around periastron. No signatures of thermal emission or a reflection iron line indicating the presence of an accretion disk are found in the spectrum, and the hydrogen column density () is compatible with being the same in both observations and consistent with the interstellar value. 2005 Chandra observations show a hard X-ray spectrum, and possibly high fluxes, although pileup effects preclude conclusive results from being obtained. The H EW shows yearly variations of 10%, and does not seem to be correlated with X-ray fluxes obtained at similar phases, unlike what is expected in the wind accretion scenario. Conclusions.2005 XMM-Newton and Chandra observations are consistent with 2003 RXTE/PCA results, namely moderate flux and spectral variability at different orbital phases. The constancy of the seems to imply that either the X-ray emitter is located at 1012 cm from the compact object, or the density in the system is 3 to 27 times smaller than that predicted by a spherical symmetric wind model. We suggest that the multiwavelength non-thermal emission of LS 5039 is related to the observed extended radio jets and is unlikely to be produced inside the binary system.

Possible hot spots excited by the relativistic jets of Cygnus X-3

We present the results of a deep search for associated radio features in the vicinity of the microquasar Cygnus X-3. The motivation behind is to find out evidence for interaction between its relativistic jets and the surrounding interstellar medium, which could eventually allow us to perform calorimetry of the total energy released by this microquasar during its flaring lifetime. Remarkably, two radio sources with mJy emission level at centimeter wavelengths have been detected in excellent alignment with the position angle of the inner radio jets. We propose that these objects could be the hot spots where the relativitic outflow collides with the ambient gas in analogy with Fanaroff-Riley II radio galaxies. These candidate hot spots are within a few arc-minutes of Cygnus X-3 and, if physically related, the full linear extent of the jet would reach tens of parsecs. We discuss here the evidence currently available to support this hypothesis based on both archival data and our own observations.

Is leishmaniosis spreading to northern areas of the Iberian Peninsula? The examples of Lleida (NE Spain) and Andorra

The entomological and canine leishmaniosis surveyscarried out in the northwest of Catalonia and in Andorra in thecontext of the European project Emerging Diseases in a changing European eNvironment (EDEN) are summarized. The aim of the study was to obtain data on the presence of leishmaniosis in these areas and the spatial distribution of their vectors.

The 2010 May Flaring Episode of Cygnus X-3 in Radio, X-rays, and ��-rays

In 2009, Cygnus X-3 (Cyg X-3) became the first microquasar to be detected in the GeV ��-ray regime, via the satellites Fermi and AGILE. The addition of this new band to the observational toolbox holds promise for building a more detailed understanding of the relativistic jets of this and other systems. We present a rich data set of radio, hard and soft X-ray, and ��-ray observations of Cyg X-3 made during a flaring episode in 2010 May. We detect a ~3 day softening and recovery of the X-ray emission, followed almost immediately by a ~1 Jy radio flare at 15 GHz, followed by a 4.3�� ��-ray flare (E > 100 MeV) ~1.5 days later. The radio sampling is sparse, but we use archival data to argue that it is unlikely the ��-ray flare was followed by any significant unobserved radio flares. In this case, the sequencing of the observed events is difficult to explain in a model in which the ��-ray emission is due to inverse Compton scattering of the companion star's radiation field. Our observations suggest that other mechanisms may also be responsible for ��-ray emission from Cyg X-3.

Confirmation of persistent radio jets in the microquasar LS 5039

We present here new observations conducted with the EVN and MERLIN of the persistent microquasar LS 5039 discovered by Paredes et al. (2000) with the VLBA. The new observations confirm the presence of an asymmetric two-sided jet reaching up to 1000 AU on the longest jet arm. The results suggest a bending of the jets with increasing distance from the core and/or precession. The origin and location of the high-energy gamma-ray emission associated with the system is discussed and an estimate of the magnetic field at the base of the jet given. Our results suggest a well collimated radio jet. We also comment on new observing strategies to be used with satellites and forthcoming detectors, since this persistent source appears to be a rather good laboratory to explore the accretion/ejection processes taking place near compact objects.

The 2010 May Flaring Episode of Cygnus X-3 in Radio, X-rays, and ��-rays

In 2009, Cygnus X-3 (Cyg X-3) became the first microquasar to be detected in the GeV ��-ray regime, via the satellites Fermi and AGILE. The addition of this new band to the observational toolbox holds promise for building a more detailed understanding of the relativistic jets of this and other systems. We present a rich data set of radio, hard and soft X-ray, and ��-ray observations of Cyg X-3 made during a flaring episode in 2010 May. We detect a ~3 day softening and recovery of the X-ray emission, followed almost immediately by a ~1 Jy radio flare at 15 GHz, followed by a 4.3�� ��-ray flare (E > 100 MeV) ~1.5 days later. The radio sampling is sparse, but we use archival data to argue that it is unlikely the ��-ray flare was followed by any significant unobserved radio flares. In this case, the sequencing of the observed events is difficult to explain in a model in which the ��-ray emission is due to inverse Compton scattering of the companion star's radiation field. Our observations suggest that other mechanisms may also be responsible for ��-ray emission from Cyg X-3.

High mass microquasars and low latitude gamma-ray sources

Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a strong concentration toward the inner spiral arms of the Galaxy. Variability, spectral and correlation analysis indicate that this population is not homogeneous. In particular, there is a subgroup of sources that display clear variability in their gamma-ray fluxes on timescales from days to months. Following the proposal by Kaufman Bernad\'o et al. (2002), we suggest that this group of sources might be high-mass microquasars, i.e. accreting black holes or neutron stars with relativistic jets and early-type stellar companions. We present detailed inhomogeneous models for the gamma-ray emission of these systems that include both external and synchrotron self-Compton interactions. We have included effects of interactions between the jet and all external photon fields to which it is exposed: companion star, accretion disk, and hot corona. We make broadband calculations to predict the spectral energy distribution of these objects from radio up to GeV energies. The results and predictions can be tested by present and future gamma-ray instruments like INTEGRAL, AGILE, and GLAST.

3D kinematics of the near-IR HH 223 outflow in L723

In this work, we derive the full 3D kinematics of the near-infrared outflow HH���223, located in the dark cloud Lynds 723 (L723), where a well-defined quadrupolar CO outflow is found. HH���223 appears projected on to the two lobes of the eastwest CO outflow. The radio continuum source VLA 2, towards the centre of the CO outflow, harbours a multiple system of low-mass young stellar objects. One of the components has been proposed to be the exciting source of the eastwest CO outflow. From the analysis of the kinematics, we get further evidence on the relationship between the near-infrared and CO outflows and on the location of their exciting source. The proper motions were derived using multi-epoch, narrow-band H2 (2.122 ��m line) images. Radial velocities were derived from the 2.122 ��m line of the spectra. Because of the extended (���5 arcmin), S-shaped morphology of the target, the spectra were obtained with the multi-object-spectroscopy (MOS) observing mode using the instrument Long-Slit Intermediate Resolution Infrared Spectrograph (LIRIS) at the 4.2 m William Herschel Telescope. To our knowledge, this work is the first time that MOS observing mode has been successfully used in the near-infrared range for an extended target.