Cortical synchronization as a neural basis for visual perception

Cortical synchronization has been suggested as a neural mechanism that is able to solve the feature binding problem. This idea has been intensively studied at neurophysiological, psychophysical and computational level. In this paper, arguments for and against the role of cortical synchronization in visual perception are critically examined. Initial neurophysiological findings of correlated neural activity in the primary visual cortex have been questioned by studies which reveal enhanced firing rate to the figure region compared to the background. Computational investigations reveal that synchronization has capacity limit. At the behavioural level, change blindness has been used as the evidence for capacity limit of visual perception. However, further examination of this issue showed that detailed visual representation exists but it is obscured by limitation of attention and visual working memory. Other behavioural phenomena, such as perceptual asynchrony, also point to the fact that there is dissociation between correlated neural activity and perception. Therefore, at present there is no sufficient evidence to support the conclusion that cortical synchronization plays a crucial role in visual perception

The role of port state control in the contemporary shipping arena from the perspective of the Paris memorandum of understanding

This article discusses the operation and effectiveness of port state control as a system of monitoring the degree of observance of international standards in the global shipping arena. Although it provides a number of criticisms of the current operation of the international port state control system, there is general support for the phenomenon in question. That support is particularly generated by the development of the Paris Memorandum of Understanding, a regional cooperation system which exists alongside the international port state regime. The achievement of the Paris Memorandum is rooted in its inspection procedures, powers of enforcement and the vessel conditions which it aims to maintain. Its success is reflected in less substandard ships operating freely on the sea and a rise in the number of states participating in regional port state frameworks

Kvalitetni registri - mreža budućnosti s otiskom klase?

This article discusses the idea of establishing a network of quality registers that would aim to reduce and eventually eliminate substandard shipping on a global scale. Although numerous other approaches with the same goal have already been adopted in practice and have achieved reasonable success, safety in shipping is still overlooked or compromised at times. This is mainly due to the existence of those ship registers, particularly open registries, that do not impose safety requirements on the vessels registered. The lack of regulation is what attracts shipowners because it offers them a financial advantage, but at the ethical expense of sacrificing safety on board. A network of quality registers would connect all the registers that follow and maintain criteria of high shipping standards in an effort to achieve a shift in the attitudes of both flag states and shipowners whereby quality in shipping will come to take priority over financial incentives. Implementation and regulation of such a network are tasks that would appear to be best fulfilled by classification societies. This is due to the sophisticated infrastructure that those societies have as well as the role they already perform. Indeed, the accomplishments of class societies render the phenomenon of a quality register network a viable one. Although bringing this idea to life in practice is likely to meet some difficulties, the potential of its future impact is promising.Ovaj rad obrađuje zamisao o utemeljenju mreže kvalitetnih registara čija bi svrha bila smanjiti i s vremenom ukloniti brodove neodgovarajućih sigurnosnih standarda. Iako se isti cilj pokušava postići na mnoge druge, donekle uspješne, načine, sigurnost u praksi brodarstva još je uvijek pojam sporedne važnosti. To je uglavnom zbog postojećih brodskih registara, pogotovo onih koji nude podobne zastave a ne zahtijevaju obavezno ispunjenje pomorskih sigurnosnih mjerila. Takav nedostatak u reguliranju je primamljiv brodarima jer im omogućuje financijske prednosti, ali o etičkom trošku žrtvovanja sigurnosnih mjera. Mreža kvalitetnih registara spajala bi sve registre koji se drže kriterija visokih pomorskih standarda. Povrh toga mreža bi nastojala postići promjene u stavovima država koje nude jeftinu i nisko reguliranu registraciju, kao i brodara, tako da na listi prioriteta u registraciji kakvoća zauzme mjesto nad financijskim pogodnostima. Čini se da bi provedbu i kontrolu takve mreže obavila klasifikacijska društva. Takva društva naime već imaju potrebnu sofističnu infrastrukturu i već odavno igraju jednu od ključnih uloga u reguliranju standarda u brodarstvu. Dakako, uspjesi klasifikacijskih društava čine fenomen o mreži registara izvodljivim. Iako bi trebalo uzeti u obzir moguće poteškoće ovakvog pothvata, potencijal njegovog budućeg utjecaja obećava mnogo

Perception as a Context for Conceptual Processing and Language Understanding

In the research on language understanding, context is defined in terms of words that help to construct the meaning of the target word or passage of text. Here, it is argued that the definition of context in language understanding should be broader in order to incorporate perception as an essential component of meaning. A theory of perceptual symbol systems is provided as a framework for understanding the role of perception in solving the symbol grounding problem for higher-level cognition. Theory posits that symbolic thought acquires its meaning only through reactivation of perceptual experiences of objects or states in the world to which the though refers to. Empirical evidence supporting the theory is also reviewed

Okratoksin A u vinu

A high-performance liquid chromatography (HPLC) method for determination of ochratoxin A (OTA) in wine was developed and checked on 14 samples of wine produced in the Republic of Croatia. OTA detection in red and white wine was validated checking the linearity of the method (r2=0.997 and 0.999, respectively), recovery (88 and 95 %, respectively), and precision (RSD=3.1 and 1.4 %, respectively). The detection limit of OTA in both red and white wine was 10 ng L-1. The OTA concentration in all red wines was above the detection limit (mean 22±11 ng L-1), while only 4 of 7 white wines contained OTA (mean 10±9 ng L-1). Three OTA-free white wines were from the north of Croatia (inland), while all wines produced in the south (Adriatic coast) were OTA-positive. However, the concentrations were too low to present a risk for a moderate wine consumer.Uvedena je metoda određivanja okratoksina A (OTA) u vinu uz pomoć tekućinske kromatografije visoke djelotvornosti i testirana na 14 uzoraka vina proizvedenih u Republici Hrvatskoj. Uzorci su pročišćeni s pomoću imunoafinitetnih kolona. Metoda je vrednovana za primjenu u crnim i bijelim vinima određivanjem linearnosti (r2=0,997, odnosno 0,999), iskorištenja (88, odnosno 95 %) i preciznosti metode (RSD=3,1, odnosno 1,4 %). Detekcijski limit za crna i bijela vina bio je 10 ng OTA L-1. Koncentracija OTA u svim je crnim vinima bila iznad detekcijskog limita (22±11 ng L-1; srednja vrijednost±standardna devijacija), dok su od 7 analiziranih bijelih vina samo 4 bila kontaminirana ovim mikotoksinom (10±9 ng L-1). Tri uzorka bijelih vina koja nisu sadržavala OTA, bila su iz sjevernog dijela Hrvatske, odnosno iz dijela s kontinentalnom klimom, dok su sva vina skupljena iz južnog dijela (Istre, Primorja i Dalmacije) sadržavala OTA. Iako je OTA bio vrlo čest nalaz u vinu, niske koncentracije upućuju na to da OTA u vinu ne predstavlja značajni izvor izloženosti ljudi ovom mikotoksinu u našoj zemlji

Mikotoksini u hrani i njihov učinak na ljudsko zdravlje

Mycotoxins are natural contaminants of cereals and other commodities throughout the world. They are produced by various strains of moulds, particularly in tropical countries. Due to significant trade of cereals, humans in temperate countries can also be exposed to mycotoxins. The most common route of exposure to mycotoxins is ingestion, but it may also involve dermal, respiratory, and parenteral routes, the last being associated with drug abuse. Apart from acute and chronic toxic effects on human health called mycotoxicosis, some mycotoxins are proved or suspected human carcinogens. This paper describes various human diseases caused by ergot, aflatoxin, ochratoxin A, 3-nitropropionic acid, trichothecene, zearalenone, and fumonisin. It also gives a quick review of human carcinogenicity evaluations of the International Agency for Research on Cancer and of regulatory limits of mycotoxin concentrations in various commodities.Mikotoksini su metaboliti plijesni čija važnost za rast i razvoj plijesni nije razjašnjena. Ti spojevi vrlo različitih kemijskih struktura onečišćuju žitarice i druge namirnice osobito u tropskim krajevima, jer viša temperatura i vlažnost pogoduju rastu plijesni. Čovjek je najčešće izložen mikotoksinima putem hrane, no u nekim slučajevima može doći do njihova udisanja, prolaska kroz kožu ili parenteralne izloženosti. Akutno i kronično oštećenje zdravlja zbog djelovanja mikotoksina naziva se mikotoksikoza, a za neke se mikotoksine pretpostavlja ili je dokazano da su karcinogeni za ljude. U ovom radu opisani su različite bolesti ili sindromi u ljudi koje uzrokuju alkaloidi ergota, aflatoksini, okratoksin A, 3-nitropropionska kiselina, trihoteceni, zearalenon i fumonizini. Iznesene su i procjene Međunarodne agencije za istraživanje karcinoma o karcinogenosti pojedinih mikotoksina, kao i zakonski propisi o dopuštenim koncentracijama pojedinih mikotoksina u različitim namirnicama