381 research outputs found
The taxonomy, chorology and ecology of Stachys menthifolia Vis. (Lamiaceae) in the north-west part of its distribution area
The taxonomy, chorology and ecology of Stachys menthifolia Visiani were studied in its north-west distribution area. Two new localities of the same species were discovered in the eastern part of the Biokovo Massif, showing that the species is spreading in a north-west direction. As these localities present the only sure and verified finding places
in Croatia, and as they form the north-west border of its distribution area, the autors suggest including this species as a rare subendemic in the next edition of the »Red book«, the vascular flora of Croatia
Effect of Environmental Conditions on <i>Escherichia coli</i> Survival in Seawater
We investigated separate and simultaneous effect of temperature, salinity and solar radiation, as well as bacterial strain and origin on Escherichia coli (E. coli) survival in seawater in experimental conditions. The experiments were carried out by placing the bottles filled with seawater of different salinity (15.0, 30.0 and 36.5 psu) and contaminated by bacterial cultures in three light‐protected air incubators set to different temperatures (6, 12, 18 and 24°C), or by placing the bottles in plastic containers filled with water of controlled temperature and exposing them to direct solar light. In experiments in the dark, two typed and two wild E. coli strains were tested. The mean T90 values were 33.55 h for E. coli ATCC 8739, 42.50 h for E. coli ATCC 35218, 72.8 h for E. coli originating from seagull feces and 278.6 h for E. coli originating from sewage, indicating differences between survival abilities among strains. The effect of temperature on T90 was significant only in seagull E. coli at 36.5 psu and sewage E. coli at 30.0 psu and was positive. The effect of salinity was significant only in seagull strain and also was positive. No interactive effect of temperature and salinity was recorded. Experiments in the presence of solar radiation, carried out with two ATCC E. coli strains, demonstrated its dominate harmful effect on bacterial cells, reducing T90 of both strains to 0.30–0.82 h for E. coli ATCC 35218 and 0.31–5.93 h for E. coli ATCC 8739. Within the ultraviolet A (UVA) and photosynthetically active radiation (PAR) spectrum of solar radiation, the wavelengths of 320–360 nm were found as most bactericidal. By comparing survival of cultivated E. coli cells to those in natural seawater samples, significantly higher survival E. coli cells in natural seawater samples was found
Development and Validation of a New Measurement Instrument: The Behavioral-Cognitive Internet Security Questionnaire (BCISQ)
Rapid changes in internet use and, consequently, digitalization of almost every aspect of human life lead inevitably to significant problems in information security and social engineering. As previous studies have shown, the biggest problem in internet security is the behavior of internet users. The aim of this study was to develop and validate a new and reliable instrument that would measure information security and awareness of every information-communication user in a short period of time. The development and validation of the new measurement instrument, the Behavioral-Cognitive Internet Security Questionnaire (BCISQ), was conducted in three phases. The final version consists of 4 subscales (2 behavioral and 2 cognitive) with a total of 17 items. The results revealed good psychometric characteristics of the BCISQ and showed that a short and reliable questionnaire measuring information security (i.e. behavioral aspects of internet security) and users’ awareness (i.e. cognitive aspects of internet security) was successfully developed
Anketno istraživanje na temu kvalitete i povjerljivosti zaporke
In this paper are presented results of empirical survey on password quality self-assessment and several privacy issues regarding password manipulation among information systems\u27 users. Data was collected by questioning 627 e-mail users that were adults, Croatian national and were using e-mail system on regular basis. Comparisons among different kind of users were done regarding age, gender, technical background knowledge, university degree and experience in usage. Results of statistical analysis have shown that most of the users\u27 passwords are of average quality while 13,8% of all users graded their password as poor. Regarding password manipulation 53,4% of all users said they use the same passwords for most of the information systems they use. In total 20,7% of all users sometimes lend their password and 17,1% of them wrote it down for remembering. Results of this study highlighted importance of using security procedures and guidelines and need of the continuous education on security issues with constant informing and alerting of information systems\u27 users. This study is an example on how to evaluate different users\u27 security awareness in order to adjust courses on security issues and to adapt informing and alerting to different groups of information systems\u27 users. However, there is great need for validated universal questionnaire for this kind of surveys.U ovome radu su prikazani rezultati empirijskog istraživanja koje je provedeno anketiranjem korisnika informacijskih sustava na temu samoprocjene kvalitete zaporke te nekoliko elemenata po pitanju privatnosti i povjerljivosti zaporke.Podaci su prikupljeni anketiranjem 627 korisnika informacijskog sustava elektroničke pošte. Svi su bili punoljetni i Hrvatski državljani koji redovito koriste sustav elektroničke pošte. Korisnici su grupirani u kategorije s obzirom na spol, starosnu dob, tehničko predznanje, stupanj obrazovanja te iskustvo u korištenju sustava kako bi se napravila usporedna analiza. Rezultati su pokazali da većina korisnika procjenjuje svoju zaporku ocjenom \u27prosječno\u27, dok 13,8% od ukupnog broja korisnika procjenjuje svoju zaporku ocjenom \u27loše\u27. Po pitanju manipulacije zaporkom, 53,4% korisnika je odgovorilo kako preferiraju koristiti istu zaporku za pristup većini korištenih informacijskih sustava; 20,7% korisnika je barem jednom posudilo svoju zaporku; dok je 17,1% korisnika negdje zapisalo svoju zaporku. Rezultati ove studije ističu važnost korištenja sigurnosnih procedura i uputa te potrebu za stalnom edukacijom, informiranjem i alarmiranjem korisnika informacijskih sustava po pitanjima informacijske sigurnosti. Također ova studija može biti primjer kako analizirati pojedine vrste korisnika, a u svrhu prilagođavanja tečajeva na temu informacijske sigurnosti, te osmišljanja metoda informiranja i alarmiranja korisnika. Postoji realna potreba za razvojem univerzalnog upitnika koji bi bio međunarodno validiran te se ne bi zasnivao samo na pitanjima vezanim uz zaporku
Development of Users' Information Security Awareness Questionnaire (UISAQ) - Ongoing Work
The user is still weakest link regarding information security matters, but studies on this subject are rare. The aim of this work is to develop general Users' Information Security Awareness Questionnaire (UISAQ). Development consists of selecting suitable items for which is assumed that measure the level of security awareness and testing impact of each item in measurement. Questionnaire consisted of 4 parts with total of 37 items. Results showed that first part of questionnaire, that examine the common user’s risk behavior, should consist of 17 items (3 items had low factor loadings) separate in 3 subscales. Second part of questionnaire, which consisted of 6 items that measured the level of user’s information security, had high internal consistency (k=6, α=0.89) and a satisfactory factor loadings. Third part of questionnaire, which consisted of 5 items that measured the level of user’s beliefs about information security, should consist of 3 items (2 items significantly disrupted internal consistency) with high factor loadings and good internal consistency (α=0.76). Descriptive statistics showed that all the questions (n=6) in the fourth part of the questionnaire, which had examined the password quality and security, had a full range of answers and that normal distribution wasn’t significantly violated. Although developed questionnaire requires more work and validation, first results showed that UISAQ has potential to become a good and reliable measure of users’ security awareness in the future
Development and Validation of Users' Information Security Awareness Questionnaire (UISAQ)
Dosadašnja su istraživanja pokazala kako je čovjek najslabija karika u sigurnosnom sustavu te kako ne postoji pouzdan način mjerenja rizičnosti čovjekova ponašanja u vidu narušavanja sigurnosti informacijskog sustava. Cilj je istraživanja bio razviti valjan i pouzdan instrument koji će mjeriti utjecaj korisnika na sigurnost informacijskog sustava. U tu je svrhu kreiran Upitnik znanja i rizičnog ponašanja korisnika informacijskog sustava (UZPK ; Velki i Šolić, 2014 ; prema Velki, Šolić i Očević, 2014). Istraživanje je provedeno u tri vala prikupljanja podataka. Prvi se uzorak sastojao od 135 studenata druge godine preddiplomskog studija na kojem je provjerena konstruktna valjanost, pouzdanost i osjetljivost pojedinih subskala te odabrane odgovarajuće čestice. Drugi se uzorak sastojao od 211 studenata i zaposlenika, a na njemu su provjerene metrijske karakteristike poboljšanog instrumenta te je dobivena konačna verzija UZPK (k=33), koja se dijeli na dvije skale: Skala rizičnog ponašanja računalnih korisnika (k=17) [sastoji se od tri supskale: Supskala uobičajenih rizičnih ponašanja korisnika računala (k=6), Supskala održavanja osobnih računalnih sustava (k=6) i Supskala posuđivanja pristupnih podataka (k=5)] te Skala znanja o informacijskoj sigurnosti (k=16) (također se sastoji od tri supskale: Supskala stupnja sigurnosti računalne komunikacije (k=5), Supskala uvjerenja o sigurnosti računalnih podataka (k=5) i Supskala važnosti pravilne pohrane računalnih podataka (k=6). Treći se uzorak sastajao od 152 zaposlenika i na njemu je validiran UZPK. Dobivena je dobra konstruktna valjanost, sve skale i supskale imaju zadovoljavajuće metrijske karakteristike (pouzdanost i osjetljivost) te je dobivena i dobra kriterijska valjanost. Može se zaključiti kako Upitnik predstavlja valjan i pouzdan mjerni instrument, zadovoljavajućih psihometrijskih karakteristika
Influence of deep cryogenic treatment of high speed steel substrate on TiAlN coating properties
La influencia de la materia orgánica y pigmentos de fitoplancton sobre la distribución de bacterias en sedimentos de la Bahía de Kaštela (mar Adriático)
Bacterial abundance, biomass, volume and morphological diversity were studied in sediments collected in the eastern Adriatic Sea (Kaštela Bay) in order to investigate their relationship with changes in environmental parameters. To asses the changes in the investigated parameters on a temporal scale and between sediment layers, the sediment samples were collected monthly in 2002 with a piston corer from the sediment surface to a depth of 10 cm. The concentrations of organic matter (OM), chloroplastic pigment equivalents (CPE), chlorophyll a (chl a) and phaeopigments (PHAEO) were used as indicators of substrate concentrations in sediments. Sediment depth was a significant factor influencing the distribution of bacterial abundance, biomass and volume. Granulometric properties of the sediment had no effect on the distribution of bacteria. Bacterial abundance, biomass and volume were strongly related to the indicators of substrate concentrations on both scales. The accumulation of labile OM in deeper layers also had a profound effect on the size and structure of bacteria. High amounts of OM and the low proportion of labile organic fraction (CPE; chl a and PHAEO) indicate that this environment acts as a sink for accumulation of detrital material.La abundancia, biomasa volumen y la diversidad morfologica bacteriana fueron estudiadas en sedimentos recogidos del este del mar Adriático (bahía de Kaštela) con el objeto de investigar su relación con los cambios de diferentes parámetros ambientales. Para establecer los cambios de los parámetros investigados a escala temporal y entre capas de sedimentos, las muestras de sedimento fueron recogidas mensualmente durante 2002, con un corer de pistón desde la superficie del sedimento hasta la profundidad de 10 cm. La concentración de materia orgánica, pigmentos cloroplastídicos equivalentes (CPE), clorofila a (chl a) y feopigmentos (PHAEO) fueron utilizados como indicadores de la concentración de sustrato en el sedimento. La profundidad del sedimento era un factor significativo en la influencia de la distribución del número de bacterias, biomasa y volumen. Las propiedades granulométricas del sedimento no tenían efecto sobre la distribución de bacterias. La abundancia, la biomasa y el volumen bacteriano estaban fuertemente relacionadas con los indicadores de sustrato en ambas escalas. La acumulación de la materia orgánica lábil en las capas más profundas tambien tenían un gran efecto sobre el tamaño y la estructura bacteriana. Una alta cantidad de materia orgánica y baja proporción de la fracción orgánica lábil (CPE; chl a y PHAEO) indica que estos ambientes actúan como sumideros para la acumulación de material detrítico
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