Cortical dynamics and synchronization related to multiple target consolidation under rapid-serial-visual-presentation conditions

The present report reviews behavioural, electroencephalographic, and especially magnetoencephalographic findings on the cortical mechanisms underlying attentional processes that separate targets from distractors and that ensure durable target representations for goal-directed action. A common way of investigation is to observe the system’s overt and covert behaviour when capacity limitations are reached. Here we focus on the aspect of temporally enhanced processing load, namely on performance deficits occurring under rapid-serial-visual-presentation (RSVP) conditions. The most prominent of these deficits is the so-called “attentional blink” (AB) effect. We first report MEG findings with respect to the time course of activation that shows modulations around 300 ms after target onset which reflect demands and success of target consolidation. Then, findings regarding long-range inter-area phase synchronization are reported that are hypothesized to mediate communication within the attentional network. Changes in synchronization reflect changes in the attentional demands of the task and are directly related to behavioural performance. Furthermore, enhanced vigilance of the system elicits systematically increased synchronization indices. A hypothetical framework is sketched out that aims at explaining limitations in multiple target consolidation under RSVP conditions.

Serial innovators in the UK:does size matter?

This article aims to shed light on the presence and importance of a significant number of small firms amongst serial innovators. Contrary to the common expectation in the innovative persistence literature, we posit that small serial innovators also benefit from operating within patterns of creative accumulation. However, it is in the quality of the technology and in the very nature of the knowledge accumulation process that the differences between small and large serial innovators can be found. Using a sample of 811 UK-based, highly innovative companies that patented over 66,000 inventions from 1990 to 2006, we find evidence in support of our theory. While large serial innovators experience higher innovation rates due to the scale of their innovation efforts, small serial innovators benefit more from processes of search depth characterized by the internal recombination of their previous knowledge. We find that important differences exist also in the very nature of the technologies being developed by small and large serial innovators.

Analysis and interpretation of serial position data

The representation of serial position in sequences is an important topic in a variety of cognitive areas including the domains of language, memory, and motor control. In the neuropsychological literature, serial position data have often been normalized across different lengths, and an improved procedure for this has recently been reported by Machtynger and Shallice (2009). Effects of length and a U-shaped normalized serial position curve have been criteria for identifying working memory deficits. We present simulations and analyses to illustrate some of the issues that arise when relating serial position data to specific theories. We show that critical distinctions are often difficult to make based on normalized data. We suggest that curves for different lengths are best presented in their raw form and that binomial regression can be used to answer specific questions about the effects of length, position, and linear or nonlinear shape that are critical to making theoretical distinctions. © 2010 Psychology Press.

Three essays on entrepreneurial entry, serial entrepreneurship, and labor turnover

This study explores two important aspects of entrepreneurship — liquidity constraints and serial entrepreneurs, with an additional analysis of occupational choice among wage workers. In the first essay, I revisit the question of whether entrepreneurs face liquidity constraints in business formation. The principle challenge is that wealth is correlated with unobserved ability, and adequate instruments are often difficult to identify. This paper uses the son's birth order as an instrument for household wealth. I exploit the data available in the Korean Labor and Income Panel Study, and find evidence of liquidity constraints associated with self-employment in South Korea. The second essay develops and tests a model that explains entry into serial entrepreneurship and the performance of serial entrepreneurs as the result of selection on innate ability. The model supposes that agents establish businesses with imperfect information about their entrepreneurial ability and the profitability of business ideas. Agents continually observe signals with which they update their beliefs, and this process eventually determines their next business choice. Selection on ability induces a positive correlation between entrepreneurial experience (measured by previous business earnings and founding experience) and serial business formation, as well as its subsequent performance. The predictions in the model are tested using panel data from the NLSY79. The analysis permits a distinction to be made between selection on innate ability and learning by doing. Motivated by previous empirical findings that white-collar workers had higher turnover rates than blue-collar workers during firm expansion, the third essay further examines job turnover among workers with or without specific skills. I present a search-matching model, which predicts that when firm growth is driven by technological advance, workers whose skills are specific to the obsolete technology show a higher tendency to separate from their jobs. This hypothesis is tested with data from the PSID. I find supportive evidence that in the context of technological change, having an occupation requiring specific skills, such as computer specialists or engineers, increases the odds of job separation by nearly eight percent. ^

Serial evolutionary networks of within-patient HIV-1 sequences reveal patterns of evolution of X4 strains

Background The HIV virus is known for its ability to exploit numerous genetic and evolutionary mechanisms to ensure its proliferation, among them, high replication, mutation and recombination rates. Sliding MinPD, a recently introduced computational method [1], was used to investigate the patterns of evolution of serially-sampled HIV-1 sequence data from eight patients with a special focus on the emergence of X4 strains. Unlike other phylogenetic methods, Sliding MinPD combines distance-based inference with a nonparametric bootstrap procedure and automated recombination detection to reconstruct the evolutionary history of longitudinal sequence data. We present serial evolutionary networks as a longitudinal representation of the mutational pathways of a viral population in a within-host environment. The longitudinal representation of the evolutionary networks was complemented with charts of clinical markers to facilitate correlation analysis between pertinent clinical information and the evolutionary relationships. Results Analysis based on the predicted networks suggests the following:: significantly stronger recombination signals (p = 0.003) for the inferred ancestors of the X4 strains, recombination events between different lineages and recombination events between putative reservoir virus and those from a later population, an early star-like topology observed for four of the patients who died of AIDS. A significantly higher number of recombinants were predicted at sampling points that corresponded to peaks in the viral load levels (p = 0.0042). Conclusion Our results indicate that serial evolutionary networks of HIV sequences enable systematic statistical analysis of the implicit relations embedded in the topology of the structure and can greatly facilitate identification of patterns of evolution that can lead to specific hypotheses and new insights. The conclusions of applying our method to empirical HIV data support the conventional wisdom of the new generation HIV treatments, that in order to keep the virus in check, viral loads need to be suppressed to almost undetectable levels.

Logical simulation of communication subsystem for Universal Serial Bus (USB)

The primary purpose of this thesis was to design a logical simulation of a communication sub block to be used in the effective communication of digital data between the host and the peripheral devices. The module designed is a Serial interface engine in the Universal Serial Bus that effectively controls the flow of data for communication between the host and the peripheral devices with the emphasis on the study of timing and control signals, considering the practical aspects of them. In this study an attempt was made to realize data communication in the hardware using the Verilog Hardware Description language, which is supported by most popular logic synthesis tools. Various techniques like Cyclic Redundancy Checks, bit-stuffing and Non Return to Zero are implemented in the design to provide enhanced performance of the module.

Separating deviant and non-deviant sexual preferences with a dual-target rapid serial visual presentation task

Forskning visar att avvikande sexuell preferens (ASP) är en av de mest centrala prediktorerna för återfall i sexualbrott. Eftersom det är viktigt att det i juridiskt beslutsfattande och behandling av sexualförbrytare finns valida och standardiserade verktyg att tillgå för bedömning av ASP, har forskningen under de senaste åren fokuserats på uppmärksamhetsbaserade metoder. Syftet med avhandlingen var att förbättra uppmärksamhetsbaserade metoder genom utvecklingen av en s.k. Rapid Serial Visual Presentation (dtRSVP) metod för att identifiera ASP. Innan vi testade sampel med sexualbrottslingar så genomförde vi tre studier för att kalibrera förfarandena. I dessa studier undersökte vi möjligheten att differentiera mellan homosexuella och heterosexuella män och hur enkelt deltagarna kunde fuska. Dessutom skapade vi en ny uppsättning standardiserade stimuli för bedömningen av pedofilt sexuellt intresse (Virtual People Set, VPS). I skapandet av stimuli togs de etiska och juridiska problemen i beaktande så långt som möjligt. När vi använde dtRSVP som mätningsförfarande för att skilja åt sexuellläggning i ett sampel av homosexuella och heterosexuella män fann vi att sexuellt relevanta stimuli påverkade informationsbehandlingen på ett förutsägbart sätt. Förfarandet hade en god förmåga att skilja sexuella preferenser mellan grupperna och förfarandet var svårt att påverka genom att fuska. När vi använde dtRSVP som mätningsförfarande för att identifiera avvikande sexuell läggning bland dömda sexbrottslingar fann vi att de visade en annorlunda bearbetning av sexuella stimuli jämfört med andra deltagare och att dessa skillnader var i de förväntade riktningarna. Det var däremot svårt att dra några slutsatser angående denna mätmetods förmåga att skilja mellan grupperna pedofiler och icke-pedofiler. Slutligen fann vi att VPS verkar vara ett användbart stimuluspaket för experimentell forskning om pedofilt sexuellt intresse. ---------------------------------------------------- Tutkimuksien mukaan poikkeava seksuaalinen mieltymys (PSM) on yksi seksuaalirikoksen uusimisen keskeisimmistä ennustajista. Oikeudellisessa päätöksenteossa ja seksuaalirikollisten hoidossa on tärkeää, että on käytettävissä kelvollisia ja standardisoituja välineitä PSM:n arvioinnissa. Sen vuoksi on tutkimuksissa viime vuosina keskitytty huomaavaisuuteen perustuviin menetelmiin. Tämän tutkielman tarkoitus oli parantaa huomaavaisuuteen perustuvia menetelmiä kehittämällä nk. Rapid Serial Visual Presentation (dtRSVP) menetelmän. Kalibroidakseen menettelytapoja suoritettiin kolme tutkimusta ennen kuin tutkittiin koeryhmää, johon kuuluvat seksuaalirikollisia. Näissä tutkimuksissa tutkittiin mahdollisuutta erotella homoseksuaalisia ja heteroseksuaalisia miehiä ja tutkittiin missä määrin osallistujien oli helppo huiputtaa. Sen lisäksi, pedofiilisen seksuaalisen mieltymyksen arviointia varten kehitettiin uutta sarjaa standardisoituja virikkeitä (Virtual People Set, VPS). Kehitettäessä virikkeitä otettiin mahdollisimman pitkälti huomioon eettisiä ja oikeudellisia ongelmia. Käytettäessä dtRSVP mittausmenetelmää erotellakseen homo- ja heteroseksuaalista suuntautumista havaitsimme, että seksuaaliset virikkeet vaikuttivat tietojenkäsittelyyn ennustettavalla tavalla. Menettelytavan avulla pystyttiin erotella koeryhmässä olevia seksuaalisia mieltymyksiä ja menettelytapaan oli vaikeaa vaikuttaa huijaamalla. Käytettäessä dtRSVP mittausmenetelmää tunnistaakseen poikkeavaa seksuaalista mieltymystä tuomittujen seksuaalirikollisten keskenään havaitsimme, että he osoittivat erilaista käsittelyä seksuaalisista virikkeistä toisiin osallistujiin verrattuna ja tulokset olivat ennustettavia. Silti oli vaikeaa tehdä johtopäätöksiä mittausmenetelmän kyvystä erotella ryhmiä pedofiilisiä ja ei-pedofiilisiä miehiä. Lopuksi havaitsimme, että VPS näyttää olevan käyttökelpoinen stimulussarja pedofiilisen seksuaalisen mieltymyksen kokeellisissa tutkimuksissa.

Storyboard: herramienta útil en el serial televisivo

El storyboardes una herramienta técnica gráfica, que contiene secuencias de dibujos, que anticipan la idea visual de un producto cinematográfico, antes de filmarse y presentarse en la pantalla. Los dibujosestablecen la forma, el ritmo, la narrativa y el solapamiento de los planos. Esta herramienta permite efectivizar el trabajo del equipo técnico y creativo. En este sentido, el guion literario se convierte en secuencias, asimismo, se divide en escenas y se transforma en planos. Estos últimos, se dibujan junto a un comentario descriptivo de la acción, la que se presenta, en términos visuales, por mediodel lenguaje cinematográfico. Además, son de utilidad en la medida en que ayudan a efectivizar la comunicación entre los departamentos técnicos, los que son el soporte para conseguir un resultado similar al de la secuencia de dibujos. Este proyecto de graduación tuvo como finalidad realizar un piloto del serial televisivo Muerte Súbita,utilizando como guía técnica de rodaje el storyboard. La historia está compuesta porseis episodios que abordan la temática de un equipo femenino de fútbol, quienes se enfrentan a distintas circunstancias, que deterioran suintegridad cuando están cerca del triunfo en un torneo de fútbol.

Sensitivity and specificity of parallel or serial serological testing for detection of canine Leishmania infection

In Brazil, human and canine visceral leishmaniasis (CVL) caused by Leishmania infantum has undergone urbanisation since 1980, constituting a public health problem, and serological tests are tools of choice for identifying infected dogs. Until recently, the Brazilian zoonoses control program recommended enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescence assays (IFA) as the screening and confirmatory methods, respectively, for the detection of canine infection. The purpose of this study was to estimate the accuracy of ELISA and IFA in parallel or serial combinations. The reference standard comprised the results of direct visualisation of parasites in histological sections, immunohistochemical test, or isolation of the parasite in culture. Samples from 98 cases and 1,327 noncases were included. Individually, both tests presented sensitivity of 91.8% and 90.8%, and specificity of 83.4 and 53.4%, for the ELISA and IFA, respectively. When tests were used in parallel combination, sensitivity attained 99.2%, while specificity dropped to 44.8%. When used in serial combination (ELISA followed by IFA), decreased sensitivity (83.3%) and increased specificity (92.5%) were observed. Serial testing approach improved specificity with moderate loss in sensitivity. This strategy could partially fulfill the needs of public health and dog owners for a more accurate diagnosis of CVL.

Endangerment and Likeability of Wildlife Species: How Important are they for Payments Proposed for Conservation?

This paper examines empirically the relative influence of the degree of endangerment of wildlife species and their stated likeability on individuals' allocation of funds for their conservation. To do this, it utilises data obtained from the IUCN Red List, and likeability and fund allocation data obtained from two serial surveys of a sample of the Australian public who were requested to assess 24 Australian wildlife species from three animal classes: mammals, birds and reptiles. Between the first and second survey, respondents were provided with extra information about the focal species. This information resulted in the dominance of endangerment as the major influence on the allocation of funding of respondents for the conservation of the focal wildlife species. Our results throw doubts on the proposition in the literature that the likeability of species is the dominant influence on willingness to pay for conservation of wildlife species. Furthermore, because the public's allocation of fund for conserving wildlife species seems to be more sensitive to information about the conservation status of species than to factors influencing their likeability, greater attention to providing accurate information about the former than the latter seems justified. Keywords: Conservation of wildlife species; Contingent valuation; Endangerment of species; Likeability of species; Willingness to pay

The Euro-American psyche and the imaging of Samoa in the early 20th century

Drawing on English language sources and material from Western Samoa (now Samoa), this examination of photographically illustrated serial encyclopaedia and magazines proposes an alternative historical analysis of the colonial photographs of Samoa, the most extensively covered field in Oceanic photographic studies. Photographs published between the 1890s and World War II were not necessarily from that era, and despite claims in the text of illustrated publications of an unchanged, enduring, archaic tradition in Samoa, the amazing variety of content and subject matter often offered contradictory evidence, depicting a modern, adaptive and progressive Samoa. Contrary to orthodox historical analysis, the images of Samoa in illustrated magazines and encyclopaedia were not limited to a small, repetitive gallery of partially clothed women and costumed chiefs.

Automated symbolic and numeric procedure for manipulator rigid-body dynamic significance analysis and simplification

This paper describes an automated procedure for analysing the significance of each of the many terms in the equations of motion for a serial-link robot manipulator. Significance analysis provides insight into the rigid-body dynamic effects that are significant locally or globally in the manipulator's state space. Deleting those terms that do not contribute significantly to the total joint torque can greatly reduce the computational burden for online control, and a Monte-Carlo style simulation is used to investigate the errors thus introduced. The procedures described are a hybrid of symbolic and numeric techniques, and can be readily implemented using standard computer algebra packages.

A simple and systematic approach to assigning Denavit-Hartenberg Parameters

This paper presents a simple and intuitive approach to determining the kinematic parameters of a serial-link robot in Denavit– Hartenberg (DH) notation. Once a manipulator’s kinematics is parameterized in this form, a large body of standard algorithms and code implementations for kinematics, dynamics, motion planning, and simulation are available. The proposed method has two parts. The first is the “walk through,” a simple procedure that creates a string of elementary translations and rotations, from the user-defined base coordinate to the end-effector. The second step is an algebraic procedure to manipulate this string into a form that can be factorized as link transforms, which can be represented in standard or modified DH notation. The method allows for an arbitrary base and end-effector coordinate system as well as an arbitrary zero joint angle pose. The algebraic procedure is amenable to computer algebra manipulation and a Java program is available as supplementary downloadable material.

Cholecystokinin and leptin: their influence upon the eating behaviour and nutrient intake of dialysis patients

Background We have used serial visual analogue scores to demonstrate disturbances of the appetite profile in dialysis patients. This is potentially important as dialysis patients are prone to malnutrition yet have a lower nutrient intake than controls. Appetite disturbance may be influenced by accumulation of appetite inhibitors such as leptin and cholecystokinin (CCK) in dialysis patients. Methods Fasting blood samples were drawn from 43 controls, 50 haemodialysis (HD) and 39 peritoneal dialysis (PD) patients to measure leptin and CCK. Hunger and fullness scores were derived from profiles compiled using hourly visual analogue scores. Nutrient intake was derived from 3 day dietary records. Results Fasting CCK was elevated for PD (6.73 ± 4.42 ng/l vs control 4.99 ± 2.23 ng/l, P < 0.05; vs HD 4.43 ± 2.15 ng/l, P < 0.01). Fasting CCK correlated with the variability of the hunger (r = 0.426, P = 0.01) and fullness (r = 0.52, P = 0.002) scores for PD. There was a notable relationship with the increase in fullness after lunch for PD (r = 0.455, P = 0.006). When well nourished PD patients were compared with their malnourished counterparts, CCK was higher in the malnourished group (P = 0.004). Leptin levels were higher for the dialysis patients than controls (HD and PD, P < 0.001) with pronounced hyperleptinaemia evident in some PD patients. Control leptin levels demonstrated correlation with fullness scores (e.g. peak fullness, r = 0.45, P = 0.007) but the dialysis patients did not. PD nutrient intake (energy and protein intake, r = -0.56, P < 0.0001) demonstrated significant negative correlation with leptin. Conclusion Increased CCK levels appear to influence fullness and hunger perception in PD patients and thus may contribute to malnutrition. Leptin does not appear to affect perceived appetite in dialysis patients but it may influence nutrient intake in PD patients via central feeding centres.