187 research outputs found

    Reading Urban Environment by Photo: A Critical Tool for Socio-Cultural Analyzing

    Get PDF
    Photography has been used as a research tool throughout a range of disciplines. In the last decades usage of photos in landscape and urban design grow noticeably; yet applying it in architectural research orĀ  education for discovering social determinations needs more attentions. In this study 34 participations in second year of architecture were involved in a photo-survey using self snapshot photography approach for the selected urban environment with open ended questionnaires in Shiraz, Iran. Despitethe observersā€™ lacks of visual research skills, they pay an equal attention to physical and social environment even in the absence of social activity facts in the photos. I argued that students used their mental image and memories of the urban space in commentaries about each photos.Ā  Besides, they used visual facts in each photo for arguing and makeĀ  conclusions logically. Yet, two kinds of challenges indentified in this study. The first emerged from ā€˜educational constraintsā€™ which has less attention tourban spaces, social and behavioral activities in architecture education and conduce to fewer commentsā€™ of observers on visual irregularities andĀ  diffusions in managing signboards, urban graffiti and faƧade designs. The second which could be named as ā€˜cultural constraintsā€™, derives from cultural legacies and historical attachments which leads observers to be more sensitive to rehabilitation and revitalization rather than new buildings.Ā  Hence, the observer approaches like this, eliminated more contemporaryinteractions between citizens and modern build environment in visualĀ  survey

    Evaluating the bioaccumulation of nickel and vanadium and their effects on the growth of Artemia urmiana and A. franciscana

    Get PDF
    Although there is growing evidence that metals can be toxic to various aquatic species, there is still insufficient knowledge to integrate this information in environmental risk assessment procedures. In this study, we have investigated bioaccumulation and effects of nickel and vanadium on mortality and growth of Artemia urmiana and Artemia franciscana. The in 24 h of A. urmiana and A. franciscana exposed to nickel and vanadium were 0.0072, 0.0114 mg/l and 0.0107 and 0.011 mg/l respectively. In growth experiments, the length of animals was considered as growth index. Results indicates that the mean length of animals in (0.001, 0.002 and 0.003 mg/l) Ni and V on first, 5th, 7th and 11th days of life significantly decreases in comparison with control groups (p<0.05).Bioaccumulation of Ni and V in the same concentration, after 24 h in nauplius and also in adults of A. urmiana and A. fransicana were statistically significantly higher than of the control groups (P < 0.05). Both species accumulate nickel and vanadium in their bodies. However A. urmiana is more resistant to the heavy metals. Results show, nickel is less toxic than vanadium on Artemia

    Multicast Network Design Game on a Ring

    Full text link
    In this paper we study quality measures of different solution concepts for the multicast network design game on a ring topology. We recall from the literature a lower bound of 4/3 and prove a matching upper bound for the price of stability, which is the ratio of the social costs of a best Nash equilibrium and of a general optimum. Therefore, we answer an open question posed by Fanelli et al. in [12]. We prove an upper bound of 2 for the ratio of the costs of a potential optimizer and of an optimum, provide a construction of a lower bound, and give a computer-assisted argument that it reaches 22 for any precision. We then turn our attention to players arriving one by one and playing myopically their best response. We provide matching lower and upper bounds of 2 for the myopic sequential price of anarchy (achieved for a worst-case order of the arrival of the players). We then initiate the study of myopic sequential price of stability and for the multicast game on the ring we construct a lower bound of 4/3, and provide an upper bound of 26/19. To the end, we conjecture and argue that the right answer is 4/3.Comment: 12 pages, 4 figure

    Determination of chemical and biochemical composition of Artemia uramiana cyst shells and its extraction chitin

    Get PDF
    Artemia urmiana cyst shells collected, purified and dried from ashore of Rashkhan and Bozorgrah in the Urmia Lake in January and February 2002. According to the results obtained by standard methods of analyses the cyst shell contains: 4.8Ā±0.5% lipid, 32Ā±2% protein, 10.5Ā±1.0% moisture, 0.5Ā±0.2% haematin and 20.6Ā±2.0% total ash. The chemical composition of ash are: Na2O 1.98%, MgO 1.14%, S03 6.82%, CI 3.23%, K20 2.12%, CaO 4.05%, Fe2O3 1.68%, Zn 0.05%. The chitin was extracted from Artemia cyst shells by using different methods of demineralizaion, delipidization, deproteinization and decolorization. The yield of extraction from cyst shells was 28Ā±3%. Composition of chitin was determined by FTIR, X-Ray Powder diffraction and C.H.N.O analyser. Artemia urmiana cyst shell contains approximately about 28Ā±3% percentage chitin

    Aberrant Frequency Related Change-Detection Activity in Chronic Tinnitus

    Get PDF
    Tinnitus is the perception of sound without the occurrence of an acoustic event. The deficit in auditory sensory or echoic memory may be the cause of the perception of tinnitus. This study considered the mismatch negativity (MMN) to investigate the potential difference between and within groups of persons with normal hearing (NH) and tinnitus. Using an auditory multi-feature paradigm to elicit the MMN, this study considered the MMN peak amplitude at two central frequencies for two MMN subcomponents. These central frequencies were 1 and 5 kHz, which the latter was closer to the perceived tinnitus frequency in the group with tinnitus. The deviants were higher frequency, lower frequency, higher intensity, lower intensity, duration, location (left), location (right), and gap. The pure tone audiometry (PTA) test and distortion product otoacoustic emissions (DPOAE) test showed no meaningful difference between the two groups. For the frontal subcomponent, the mean amplitudes of the MMN peak for the two groups illustrated less negative meaningful MMN peak amplitudes in the group of persons with tinnitus. For the supratemporal component at 5 kHz central frequency, amplitudes were lower for the group of persons with tinnitus, whereas for the central frequency of 1 kHz, most deviants exhibited meaningful differences. Additionally, within-group comparisons indicated that mean amplitudes for both groups were more negative at the central frequency of 1 kHz for the frontal MMN subcomponent. In comparison, the supratemporal component illustrated a lower peak amplitude at 5 kHz central frequency in the group of persons with tinnitus and no difference in the NH group, which is a unique observation of this study. Results of the between-groups are in accordance with previous studies and within-group comparisons consider the probability of decreasing the change detection capability of the brain. The results of this study indicate that increasing the frequency of the stimuli close to the tinnitus perceived frequencies decreases the prediction error, including the prediction error of the silence. Such a decrease may cause the prediction error of the spontaneous neural activity in the auditory pathway to exceed the silence prediction error, and as a result, increases the probability of occurrence of tinnitus in higher frequencies according to the predictive coding model. ƂĀ© Copyright ƂĀ© 2020 Asadpour, Jahed and Mahmoudian

    Fluctuation of gonadosomatic index during oocyte development in the narrow-clawed crayfish Astacus leptodactylus (Eschscholtz, 1823) in Aras Dam Lake, Iran

    Get PDF
    This study was carried out with the aim of examining the seasonal reproductive cycle of the female crayfish Astacus leptodactylus from Aras Dam Lake, Western-Azerbaijan, Iran. Gonadosomatic index (GSI), and oocyte size were measured in females sampled seasonally in June, August, November (2011), January (2012). Development of the oocytes was categorized according to the diameter and the presence/absence of yolk granules. The ovary development was accompanied by increasing levels gonadosomatic index and egg diameter. Ovarian development histologicaly related to the seasonal GSI . This index was low in June (0.61Ā±0.05) when oocytes started developing and reached the highest value in November (13.53Ā±0.25), when vitellogenic oocytes were abundant in the mature ovary. Our results highlight the relationship between the ovary development and the GSI and egg diameter in the crayfish A. leptodactylus during the reproductive cycle and held important implications for the management of aquatic species. Thus, investigation of female A. leptodactylus reproduction is highly significant for fisheries managers as well as environmentalists concerned with perpetuating crayfish stocks

    An EPTAS for Scheduling on Unrelated Machines of Few Different Types

    Full text link
    In the classical problem of scheduling on unrelated parallel machines, a set of jobs has to be assigned to a set of machines. The jobs have a processing time depending on the machine and the goal is to minimize the makespan, that is the maximum machine load. It is well known that this problem is NP-hard and does not allow polynomial time approximation algorithms with approximation guarantees smaller than 1.51.5 unless P==NP. We consider the case that there are only a constant number KK of machine types. Two machines have the same type if all jobs have the same processing time for them. This variant of the problem is strongly NP-hard already for K=1K=1. We present an efficient polynomial time approximation scheme (EPTAS) for the problem, that is, for any Īµ>0\varepsilon > 0 an assignment with makespan of length at most (1+Īµ)(1+\varepsilon) times the optimum can be found in polynomial time in the input length and the exponent is independent of 1/Īµ1/\varepsilon. In particular we achieve a running time of 2O(Klogā”(K)1Īµlogā”41Īµ)+poly(āˆ£Iāˆ£)2^{\mathcal{O}(K\log(K) \frac{1}{\varepsilon}\log^4 \frac{1}{\varepsilon})}+\mathrm{poly}(|I|), where āˆ£Iāˆ£|I| denotes the input length. Furthermore, we study three other problem variants and present an EPTAS for each of them: The Santa Claus problem, where the minimum machine load has to be maximized; the case of scheduling on unrelated parallel machines with a constant number of uniform types, where machines of the same type behave like uniformly related machines; and the multidimensional vector scheduling variant of the problem where both the dimension and the number of machine types are constant. For the Santa Claus problem we achieve the same running time. The results are achieved, using mixed integer linear programming and rounding techniques

    A Supervised Approach to Predict the Hierarchical Structure of Conversation Threads for Comments

    Get PDF
    User-generated texts such as comments in social media are rich sources of information. In general, the reply structure of comments is not publicly accessible on the web. Websites present comments as a list in chronological order. This way, some information is lost. A solution for this problem is to reconstruct the thread structure (RTS) automatically. RTS predicts a semantic tree for the reply structure, useful for understanding usersā€™ behaviours and facilitating follow of the actual conversation streams. This paper works on RTS task in blogs, online news agencies, and news websites. These types of websites cover various types of articles reflecting the real-world events. People with different views participate in arguments by writing comments. Comments express opinions, sentiments, or ideas about articles. The reply structure of threads in these types of websites is basically different from threads in the forums, chats, and emails. To perform RTS, we define a set of textual and nontextual features. Then, we use supervised learning to combine these features. The proposed method is evaluated on five different datasets. The accuracy of the proposed method is compared with baselines. The results reveal higher accuracy for our method in comparison with baselines in all datasets
    • ā€¦
    corecore