136 research outputs found
Construction of earthen structure as a sexual signals in the fiddler crabs
We studied the reproductive behavior and the construction of an earthen structure in the four species of fiddler crab with reference to their habitat. Males of the Uca sindensis and U. iranica inhibit on open mudflats, construct the pillar and semidome structures at or near to the burrows openings. These structures perform the function to attract females, who wandering on the surface between male burrows for mating as well as provide protection or hiding object against the avian predator to mates. There were no earthen structures were observed in U. urvillie and U. annulipes, which inhibit among the vegetation. The well-marked intersexual different arrangement of mudballs was observed in U. annulipes. The earthen structures (pillar and semidome) and mudballs arrangements help courting females to assess the quality of mate as well as internal conditions of the burrow
Allometric growth pattern, sexual dimorphism and size at the onset of sexual maturity in Opusia indica (Brachyura: Ocypodoidea: Camptandriidae) from mangrove areas of Pakistan
Size at sexual maturity and patterns of somatic growth are important aspects of reproductive history of crab. The main purpose of this study is to provide an estimate for the onset of morphological sexual maturity in mangrove crab, Opusia indica from a population located in Korangi creek intertidal mud flat (Karachi, Pakistan) based on relative growth. The crabs were monthly collected through quadrat method from March 2001 to February 2002. A total of 1702 crabs was obtained, of which 764 were males, 939 were female. The morphometric measurement of carapace, abdomen, cheliped and male gonopod was related to carapace width. Based on carapace width males were significantly larger than female, indicating sexual dimorphism. The size at onset of sexual maturity in males was estimated as 5.51 mm carapace width and 5.3 mm carapace width in females. The positive allometric growth of female abdominal width were likely related to the incubation process
Diversity and distribution of mangrove crabs in three intertidal areas of Balochistan, Pakistan
The mangrove crab diversity and densities were studied by transect
analyses from three coastal sites (Bhaira, Dam and Miani) of Balochistan. Among all the macrofauna inhabiting in the mangrove swamps, some brachyuran crab species are among the most important taxa with regard to species diversity and distribution The brachyuran crabs were collected from the low tide level to high tide level. Diversity and distribution of crabs were significantly different between the sites and among tidal levels.
A total of 14 species of brachyuran crabs was recorded belongs to the family Ocypodidae, Macrophthalmidae, Dotillidae, Camptandriidae, Grapsidae and Xanthidae. The 11 species were from the Bhaira mangroves, while 10 species were recorded in Miani mangroves. The abundance of crabs varied between the tide levels among three habitats
Tidal induced variation in the distribution, abundance and diversity of mesozooplankton along the Karachi coast, Pakistan
Temporal variations in biomass, abundance, diversity and species
composition of mesozooplankton in relation to the tidal state were studied.
Mesozooplankton sampling was carried out twice at the ebb and flood tides at fixed
stations closed to Phitti creek (P) and Manora channel (M) near the Karachi coast during
February 1999. The average percent abundance of mesozooplankton was high at ebb tide
i.e., 66% and 63% whereas, low on flood tide i.e.,34% and 37%, at both stations
respectively. However, there were no differences in species composition with tidal
fluctuations at both sites. The mesozooplankton community was typically composed of
22 groups, out of which copepod was the most abundant group (comprising % of the total
zooplankton) at both sites. During the flood tide high diversity 0.11 ± 0.021 was observed
in Phitti creek, but no difference was observed at Manora channel. The species richness
was high (2.30 ± 0.01273 and 2.38 ± 0.502) in the Manora channel at both ebb and flood
tides, respectively, whereas the dominance values were high at Phitti creek. Complete
randomized design ANOVA showed that there was no significant difference in
abundance of mesozooplankton between stations and tides nested in stations, but the
difference was significant for the diversity and equitability. On the short temporal scale
the tidal cycle additionally determines changes in the zooplankton composition
E-Ensemble: A Novel Ensemble Classifier for Encrypted Video Identification
In recent years, video identification within encrypted network traffic has gained popularity for many reasons. For example, a government may want to track what content is being watched by its citizens, or businesses may want to block certain content for productivity. Many such reasons advocate for the need to track users on the internet. However, with the introduction of the secure socket layer (SSL) and transport layer security (TLS), it has become difficult to analyze traffic. In addition, dynamic adaptive streaming over HTTP (DASH), which creates abnormalities due to the variable-bitrate (VBR) encoding, makes it difficult for researchers to identify videos in internet traffic. The default quality settings in browsers automatically adjust the quality of streaming videos depending on the network load. These auto-quality settings also increase the challenge in video detection. This paper presents a novel ensemble classifier, E-Ensemble, which overcomes the abnormalities in video identification in encrypted network traffic. To achieve this, three different classifiers are combined by using two different combinations of classifiers: the hard-level and soft-level combinations. To verify the performance of the proposed classifier, the classifiers were trained on a video dataset collected over one month and tested on a separate video dataset captured over 20 days at a different date and time. The soft-level combination of classifiers showed more stable results in handling abnormalities in the dataset than those of the hard-level combination. Furthermore, the soft-level classifier combination technique outperformed the hard-level combination with a high accuracy of 81.81%, even in the auto-quality mode
Feeding Diversity of Finfish in Different Wild Habitat
Sonmiani Bay has unique faunal diversity and distribution especially finfish as mangroves provides an imperative ecosystem which offer the shelter and protection to the associated organisms and care of their juveniles in bay limits. This study aimed to evaluate the diversity pattern according to physical and physiological responses and feeding habits (carnivorous and herbivorous) of finfish species in accordance with current habitat conditions in the Sonmiani Bay. A total of 4499, individuals of comprising 155 finfish species that represent 50 families were captured by these four (beach seines, purse seines, gill nets, and cast nets) nets during a twelve-month survey in a year. The distribution pattern of finfishes captured classified into four groups (tidal visitors, permanent residents, partial residents, and seasonal visitors) according to their patterns of distribution. Understanding of the true feeding behavior of organisms needs a more reliable and functional approach. The feeding ecology is not only functional for food and feeding behavior of fish as usually described by various tools and techniques of analytical research to take up more reliable details to explain the feeding biology in fish but also the indicator of habitat quality and status
Diagnostic accuracy of contrast-enhanced MR angiography in severe carotid stenosis: meta-analysis with metaregression of different techniques
Contrast-enhanced magnetic resonance angiography (CE-MRA) has become a well-established noninvasive imaging method for the assessment of severe carotid stenosis (70–99% by NASCET criteria). However, CE-MRA is not a standardised technique, but encompasses different concurrent techniques. This review analyses possible differences. A bivariate random effects meta-analysis of 17 primary diagnostic accuracy studies confirmed a high pooled sensitivity of 94.3% and specificity of 93.0% for carotid CE-MRA in severe carotid stenosis. Sensitivity was fairly uniform among the studies, while specificity showed significant variation (I2 = 73%). Metaregressions found significant differences for specificity with two covariates: specificity was higher when using not only maximum intensity projection (MIP) images, but also three-dimensional (3D) images (P = 0.01). Specificity was also higher with electronic images than with hardcopies (P = 0.02). The timing technique (bolus-timed, fluoroscopically triggered or time-resolved) did not result in any significant differences in diagnostic accuracy. Some nonsignificant trends were found for the percentages of severe carotid disease, acquisition time and voxel size. In conclusion, in CE-MRA of severe carotid stenosis the three major timing techniques yield comparably high diagnostic accuracy, electronic images are more specific than hardcopies, and 3D images should be used in addition to MIP images to increase the specificity
A study of the precursors leading to 'organisational' accidents in complex industrial settings
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