Behavioral aspects of investment fund's markets: are good managers lucky or skilled?

It is generally accepted that financial markets are efficient in the long run a lthough there may be some deviations in the short run. It is also accepted that a good portfolio manager is the one who beats the market persistently along time, this type of manager could not exist if markets were perfectly efficient According to this in a pure efficient market we should find that managers know that they can not beat the market so they would undertake only pure passive management strategies. Assuming a certain degree of inefficiency in the short run, a market may show some managers who tr y to beat the market by undertaking active strategies. From Fama’s efficient markets theory we can state that these active managers may beat the market occasionally although they will not be able to enhance significantly their performance in the long run. On the other hand, in an inefficient market it would be expected to find a higher level of activity related with the higher probability of beating the market. In this paper we follow two objectives: first, we set a basis to analyse the level of efficiency in an asset invest- ment funds market by measuring performance, strategies activity and it’s persistence for a certain group of funds during the period of study. Second, we analyse individual performance persistence in order to determine the existence of skilled managers. The CAPM model is taken as theoretical background and the use of the Sharpe’s ratio as a suitable performance measure in a limited information environment leads to a group performance measurement proposal. The empiri- cal study takes quarterly data from 1999-2007 period, for the whole population of the Spanish asset investment funds market, provided by the CNMV (Comisión Nacional del Mercado de Valores). This period of study has been chosen to ensure a wide enough range of efficient market observation so it would allow us to set a proper basis to compare with the following period. As a result we develop a model that allows us to measure efficiency in a given asset mutual funds market, based on the level of strategy’s activity undertaken by managers. We also observe persistence in individual performance for a certain group of funds

Robust synchronization of coupled circadian and cell cycle oscillators in single mammalian cells.

Circadian cycles and cell cycles are two fundamental periodic processes with a period in the range of 1 day. Consequently, coupling between such cycles can lead to synchronization. Here, we estimated the mutual interactions between the two oscillators by time-lapse imaging of single mammalian NIH3T3 fibroblasts during several days. The analysis of thousands of circadian cycles in dividing cells clearly indicated that both oscillators tick in a 1:1 mode-locked state, with cell divisions occurring tightly 5 h before the peak in circadian Rev-Erbα-YFP reporter expression. In principle, such synchrony may be caused by either unidirectional or bidirectional coupling. While gating of cell division by the circadian cycle has been most studied, our data combined with stochastic modeling unambiguously show that the reverse coupling is predominant in NIH3T3 cells. Moreover, temperature, genetic, and pharmacological perturbations showed that the two interacting cellular oscillators adopt a synchronized state that is highly robust over a wide range of parameters. These findings have implications for circadian function in proliferative tissues, including epidermis, immune cells, and cancer.

Electronic couplings and on-site energies for hole transfer in DNA: systematic quantum mechanical/molecular dynamic study

The electron hole transfer (HT) properties of DNA are substantially affected by thermal fluctuations of the π stack structure. Depending on the mutual position of neighboring nucleobases, electronic coupling V may change by several orders of magnitude. In the present paper, we report the results of systematic QM/molecular dynamic (MD) calculations of the electronic couplings and on-site energies for the hole transfer. Based on 15 ns MD trajectories for several DNA oligomers, we calculate the average coupling squares 〈 V2 〉 and the energies of basepair triplets X G+ Y and X A+ Y, where X, Y=G, A, T, and C. For each of the 32 systems, 15 000 conformations separated by 1 ps are considered. The three-state generalized Mulliken-Hush method is used to derive electronic couplings for HT between neighboring basepairs. The adiabatic energies and dipole moment matrix elements are computed within the INDO/S method. We compare the rms values of V with the couplings estimated for the idealized B -DNA structure and show that in several important cases the couplings calculated for the idealized B -DNA structure are considerably underestimated. The rms values for intrastrand couplings G-G, A-A, G-A, and A-G are found to be similar, ∼0.07 eV, while the interstrand couplings are quite different. The energies of hole states G+ and A+ in the stack depend on the nature of the neighboring pairs. The X G+ Y are by 0.5 eV more stable than X A+ Y. The thermal fluctuations of the DNA structure facilitate the HT process from guanine to adenine. The tabulated couplings and on-site energies can be used as reference parameters in theoretical and computational studies of HT processes in DNA

Conformations of poly{G}-poly{C} π stacks with high hole mobility

Charge transfer properties of DNA depend strongly on the π stack conformation. In the present paper, we identify conformations of homogeneous poly-{G}-poly-{C} stacks that should exhibit high charge mobility. Two different computational approaches were applied. First, we calculated the electronic coupling squared, V2, between adjacent base pairs for all 1 ps snapshots extracted from 15 ns molecular dynamics trajectory of the duplex G15. The average value of the coupling squared 〈 V2 〉 is found to be 0.0065 eV2. Then we analyze the base-pair and step parameters of the configurations in which V2 is at least an order of magnitude larger than 〈 V2 〉. To obtain more consistent data, ∼65 000 configurations of the (G:C)2 stack were built using systematic screening of the step parameters shift, slide, and twist. We show that undertwisted structures (twist<20°) are of special interest, because the π stack conformations with strong electronic couplings are found for a wide range of slide and shift. Although effective hole transfer can also occur in configurations with twist=30° and 35°, large mutual displacements of neighboring base pairs are required for that. Overtwisted conformation (twist38°) seems to be of limited interest in the context of effective hole transfer. The results may be helpful in the search for DNA based elements for nanoelectronics

A unified treatment of optimum pilot overhead in multipath fading channels

The optimization of the pilot overhead in single-user wireless fading channels is investigated, and the dependence of this overhead on various system parameters of interest (e.g., fading rate, signal-to-noise ratio) is quantified. The achievable pilot-based spectral efficiency is expanded with respect to the fading rate about the no-fading point, which leads to an accurate order expansion for the pilot overhead. This expansion identifies that the pilot overhead, as well as the spectral efficiency penalty with respect to a reference system with genie-aided CSI (channel state information) at the receiver, depend on the square root of the normalized Doppler frequency. It is also shown that the widely-used block fading model is a special case of more accurate continuous fading models in terms of the achievable pilot-based spectral efficiency. Furthermore, it is established that the overhead optimization for multiantenna systems is effectively the same as for single-antenna systems with the normalized Doppler frequency multiplied by the number of transmit antennas.

Non-peaky signals in wideband fading channels: achievable bit rates and optimal bandwidth

In the context of fading channels it is well established that, with a constrained transmit power, the bit rates achievable by signals that are not peaky vanish as the bandwidth grows without bound. Stepping back from the limit, we characterize the highest bit rate achievable by such non-peaky signals and the approximate bandwidth where that apex occurs. As it turns out, the gap between the highest rate achievable without peakedness and the infinite-bandwidth capacity (with unconstrained peakedness) is small for virtually all settings of interest to wireless communications. Thus, although strictly achieving capacity in wideband fading channels does require signal peakedness, bit rates not far from capacity can be achieved with conventional signaling formats that do not exhibit the serious practical drawbacks associated with peakedness. In addition, we show that the asymptotic decay of bit rate in the absence of peakedness usually takes hold at bandwidths so large that wideband fading models are called into question. Rather, ultrawideband models ought to be used.

Interplay of spectral efficiency, power and doppler spectrum for reference-signal-assisted wireless communication

Expressions relating spectral efficiency, power, and Doppler spectrum, are derived for Rayleigh-faded wireless channels with Gaussian signal transmission. No side information on the state of the channel is assumed at the receiver. Rather, periodic reference signals are postulated in accordance with the functioning of most wireless systems. The analysis relies on a well-established lower bound, generally tight and asymptotically exact at low SNR. In contrast with most previous studies, which relied on block-fading channel models, a continuous-fading model is adopted. This embeds the Doppler spectrum directly in the derived expressions, imbuing them with practical significance. Closed-form relationships are obtained for the popular Clarke-Jakes spectrum and informative expansions, valid for arbitrary spectra, are found for the low- and high-power regimes. While the paper focuses on scalar channels, the extension to multiantenna settings is also discussed.

Optimum power allocation for parallel Gaussian channels with arbitrary input distributions

The mutual information of independent parallel Gaussian-noise channels is maximized, under an average power constraint, by independent Gaussian inputs whose power is allocated according to the waterfilling policy. In practice, discrete signalling constellations with limited peak-to-average ratios (m-PSK, m-QAM, etc) are used in lieu of the ideal Gaussian signals. This paper gives the power allocation policy that maximizes the mutual information over parallel channels with arbitrary input distributions. Such policy admits a graphical interpretation, referred to as mercury/waterfilling, which generalizes the waterfilling solution and allows retaining some of its intuition. The relationship between mutual information of Gaussian channels and nonlinear minimum mean-square error proves key to solving the power allocation problem.

Optimum power allocation for multiuser OFDM with arbitrary signal constellations

This paper formulates power allocation policies that maximize the region of mutual informationsachievable in multiuser downlink OFDM channels. Arbitrary partitioning ofthe available tones among users and arbitrary modulation formats, possibly different forevery user, are considered. Two distinct policies are derived, respectively for slow fadingchannels tracked instantaneously by the transmitter and for fast fading channels knownonly statistically thereby. With instantaneous channel tracking, the solution adopts theform of a multiuser mercury/waterfilling procedure that generalizes the single-user mercury/waterfilling introduced in [1, 2]. With only statistical channel information, in contrast,the mercury/waterfilling interpretation is lost. For both policies, a number of limitingregimes are explored and illustrative examples are provided.

What can spike train distances tell us about the neural code?

Time scale parametric spike train distances like the Victor and the van Rossum distancesare often applied to study the neural code based on neural stimuli discrimination.Different neural coding hypotheses, such as rate or coincidence coding,can be assessed by combining a time scale parametric spike train distance with aclassifier in order to obtain the optimal discrimination performance. The time scalefor which the responses to different stimuli are distinguished best is assumed to bethe discriminative precision of the neural code. The relevance of temporal codingis evaluated by comparing the optimal discrimination performance with the oneachieved when assuming a rate code.We here characterize the measures quantifying the discrimination performance,the discriminative precision, and the relevance of temporal coding. Furthermore,we evaluate the information these quantities provide about the neural code. Weshow that the discriminative precision is too unspecific to be interpreted in termsof the time scales relevant for encoding. Accordingly, the time scale parametricnature of the distances is mainly an advantage because it allows maximizing thediscrimination performance across a whole set of measures with different sensitivitiesdetermined by the time scale parameter, but not due to the possibility toexamine the temporal properties of the neural code.

Per-antenna rate and power control for MIMO layered architectures in the low- and high-power regimes

In a MIMO layered architecture, several codewordsare transmitted from a multiplicity of antennas. Although thespectral efficiency is maximized if the rates of these codewordsare separately controlled, the feedback rate within the linkadaptation loop is reduced if they are constrained to be identical.This poses a direct tradeoff between performance andfeedback overhead. This paper provides analytical expressionsthat quantify the difference in spectral efficiency between bothapproaches for arbitrary numbers of antennas. Specifically, thecharacterization takes place in the realm of the low- and highpowerregimes via expansions that are shown to have a widerange of validity.In addition, the possibility of adjusting the transmit powerof each codeword individually is considered as an alternative tothe separate control of their rates. Power allocation, however,turns out to be inferior to rate control within the context of thisproblem.

What is the value of joint processing of pilots and data in block-fading channels?

The spectral efficiency achievable with joint processing of pilot and data symbol observations is compared with that achievable through the conventional (separate) approach of first estimating the channel on the basis of the pilot symbols alone, and subsequently detecting the datasymbols. Studied on the basis of a mutual information lower bound, joint processing is found to provide a non-negligible advantage relative to separate processing, particularly for fast fading. It is shown that, regardless of the fading rate, only a very small number of pilot symbols (at most one per transmit antenna and per channel coherence interval) shouldbe transmitted if joint processing is allowed.

Identity, immigration, and prejudice in Europe: a recognition approach

Social identity is a double-edged sword. On the one hand, identifying with a social group is a prerequisite for the sharing of common norms and values, solidarity, and collective action. On the other hand, in-group identification often goes together with prejudice and discrimination. Today, these two sides of social identification underlie contradictory trends in the way European nations and European nationals relate to immigrants and immigration. Most European countries are becoming increasingly multicultural, and anti-discrimination laws have been adopted throughout the European Union, demonstrating a normative shift towards more social inclusion and tolerance. At the same time, racist and xenophobic attitudes still shape social relations, individual as well as collective behaviour (both informal and institutional), and political positions throughout Europe. The starting point for this chapter is Sanchez-Mazas' (2004) interactionist approach to the study of racism and xenophobia, which in turn builds on Axel Honneth's (1996) philosophical theory of recognition. In this view, the origin of attitudes towards immigrants cannot be located in one or the other group, but in a dynamic of mutual influence. Sanchez-Mazas' approach is used as a general framework into which we integrate social psychological approaches of prejudice and recent empirical findings examining minority-majority relations. We particularly focus on the role of national and European identities as antecedents of anti-immigrant attitudes held by national majorities. Minorities' reactions to denials of recognition are also examined. We conclude by delineating possible social and political responses to prejudice towards immigrants.

Yhteistoiminnallinen hoitotyö

Opinnäytetyön tarkoituksena on selvittää, mitä on yhteistoiminnallinen hoitotyö. Opinnäyteytössä määritellään yhteistoiminnallisen hoitotyön käsite ja sisältö. Työssä on tarkasteltu yhteistoiminnallisuutta selittäviä käsitteitä. Opinnäytetyö on osa laajempaa projektia, jossa on mukana HUS:n Psykiatriakeskus, Helsingin kaupungin terveyskeskuksen psykiatrian osasto sekä Helsingin ammattikorkeakoulu Stadia. Projekin tarkoituksena on kehittää psykiatrisen hoitotyön käytäntöä yhteistoiminnalliseksi. Opinnäytetyö on tehty soveltaen systemaattisen kirjallisuuskatsauksen mallia. Aineisto koostuu yhteensä kolmestatoista lähteestä. Mukana on väitöskirjoja, pro gradu- tutkielmia sekä tutkimusartikkeleita, jotka on julkaistu hoitotieteellisissä julkaisuissa. Kirjallisuuskatsauksen tuloksina nousi esiin, että yhteistoiminnallinen hoitotyö on potilaan ja hoitajan välistä yhteistyötä. Se on potilaslähtöinen tapa tehdä hoitotyötä, jossa otetaan huomioon potilaan voimavarat ja tarpeet. Potilas on vastuullinen osallistuja. Jokainen hoitoon osallistuva määrittelee hoidon tavoitteen ja kukin osallistuu siihen tasavertaisesti. Yhteistoiminnallisuuteen kuuluu molemminpuolinen luottamus. Kaikki osapuolet vaikuttuvat toisistaan ja dialogisuuden avulla voidana löytää uusia näkökulmia hoitoon. Yhteistoiminnallisuus on uusi käsite hoitotyössä. Sen ymmärtäminen ja toteutuminen vaatii hoitotyön tekijöiden perehdyttämistä syvällisemmin aiheeseen. Se vaatii potilaalta mahdollisuutta osallistua voimavarojensa mukaan hoitoon. Yhteistoiminnallisen hoitotyön avulla voidaan motivoida potilasta aktiivisempaan rooliin omassa hoidossaan.

Kaupungin ja maaseudun vuorovaikutus alueellisessa kehittämispolitiikassa

In Finland, European Union membership and economic globalisation have changed the position of regions from closed territorial systems to nodes of open international networks. The increasing complexity of cities as globalised knowledge centres and functionally specialised and diversified rural areas, and on the other hand growing disparities between prosperous urban cores and lagging peripheral areas are also essential features in contemporary regional development. These trends have produced new needs to promote mutual dialogue between cities and the countryside in western market economies. Urban-rural interaction is an idea which was developed in the late 1990s within regional policy to pull together these new challenges to regional development and handle cities and the countryside as a whole. The aim of my study is to conceptualise the idea of urban-rural interaction, explain the phenomenon theoretically, clarify past and present urban and rural development and analyse regional policies from the interaction angle. The ultimate purpose is to illustrate the existence and nature of particular interaction policy in a globalising society. The general method is discourse analysis, which I use in three cases: Central Finland, South-Ostrobothnia and South-West Finland. Theoretically I have a two-dimensional approach. On the first hand I use World-System theory to explain how the global economy is moulding urban and rural structures at the regional level. On the other hand I use regime theory to explain local political actions and practises between cities and the countryside under the overlapping pressures deriving from reformulated regional structures and policies.

Adaptation to globalisation in Finland has been carried out by strengthening urban centres. The stress in regional policy has been in urban development. The development of the countryside has mostly been implemented by a separate rural policy. At the end of the 1990s and early 2000s Finnish cities have actually shown themselves to be competitive in global markets. The drawbacks of the new growth centre policy have been the sparse network of prosperous cities and their weak spreading effects, which have hindered comprehensive regional development. Tensions between urban and rural areas have also deepened. In this situation the interaction policy is used as a way of balancing development and moderate conflicts within the regions. From this point of view urban-rural interaction can be seen as a way of tackling the challenges of globalisation.

On the other hand the results emphasise that actors involved in regional development still believe, although the hegemonic discourse is on urban policy, that there are opportunities to stimulate progress in the countryside as well. In the situation where regional authorities control development resources, rural development can be successful only if rural actors manage to establish fruitful relationships with their urban partners. This is also the weakness of the programme-based regional policy. If rural municipalities or other actors are for any reason incapable of building development regimes with cities, the offers of interaction policy will be useless.

The problem of the interaction policy is that the focus and methods of it have so far been rather underdeveloped. In order to improve the efficiency of the interaction policy, further research should concentrate on the social processes which define the position of cities and the countryside as partners of interaction, and practises which promote or prohibit the possibilities of developing the interaction policy. The efforts to define different contents of urban-rural interaction or promote interaction projects should not have such an important role in the future as they have had so far. Instead, the focus of interaction policy should be on questions such as how to manage the political tensions between town and country and how to create a positive atmosphere for regional policy where the needs of urban and rural development are promoted equally.