Length Frequency Research Articles

Population dynamics of the Nile tilapia (Oreochromis niloticus L. 1758) stock in Lake Langeno, Ethiopia

Nile tilapia, Oreochromis niloticus, is a widely distributed and economically most import fish species in Ethiopia. Effective management is essential to sustain their fisheries and the benefits for the local communities. However, little is known about the population dynamics of the Nile tilapia stock in Lake Langeno. Vital parameters of its population were determined using length frequency data collected from 5,949 specimens ranging from 8.5 to 35.7 cm total length (tl). These specimens were collected from August 2017to July 2018. The population parameters were determined using the elefan I routine in FiSAT software. Estimated von Bertalanffy growth parameters were asymptotic length (L∞) = 35.70 cm, growth curvature (K) = 0.32 yr-1, age at length zero (to) = -0.49, and growth performance index (Փ') = 2.61. Instantaneous total mortality (Z), natural mortality (M), and fishing mortality (F) rates were determined from length-converted catch curve and empirical models, respectively, and their values obtained were Z = 2.31 yr-1, M = 0.82 and F =1.56 yr-1, respectively. The exploitation rate (E) of Nile tilapia computed from its mortality rates was 0.67 yr-1, suggesting state of overfishing. The size at first capture (Lc) was estimated at 14.0 cm which is much lower than the size at first maturity (Lm=16.62 cm), which further substantiated the state of overfishing. The results of the study are very useful for fishery managers and scientists who wish to manage and further explore the Nile tilapia stock in Lake Langeno.

Genome-Wide Analysis of Odorant and Gustatory Receptors in Six Papilio Butterflies (Lepidoptera: Papilionidae).

Simple SummaryThe butterflies of the Lepidoptera are representatives of herbivorous insects. Host plant diversities may shape the evolution of chemosensory receptors in butterflies. However, little is known about whether the host plant range is correlated with the size differences of chemoreceptors as key molecular targets for butterfly–plant chemical interactions. Here, we characterized 381 odorant (ORs) and 328 gustatory (GRs) receptors in one Papilio generalist and five other Papilio specialists regarding their comprehensive annotation, gene structure, phylogenetics and expression profiles. Among six Papilio species, orthologous ORs or GRs shared conserved gene structure, but the differences in intron size frequencies were observed between the generalist and the specialists. Furthermore, expression profiles identified candidate OR and GR genes in antennae, foretarsi or reproductive tissues of P. xuthus. This study addresses, for the first time, the issue that the breath of host plants does not appear to result in the obvious expansions of ORs and GRs in Papilio butterflies and identifies candidate molecular targets associated with olfaction, oviposition or reproduction in P. xuthus.The chemical interactions of insects and host plants are shaping the evolution of chemosensory receptor gene families. However, the correlation between host range and chemoreceptor gene repertoire sizes is still elusive in Papilionidae. Here, we addressed the issue of whether host plant diversities are correlated with the expansions of odorant (ORs) or gustatory (GRs) receptors in six Papilio butterflies. By combining genomics, transcriptomics and bioinformatics approaches, 381 ORs and 328 GRs were annotated in the genomes of a generalist P. glaucus and five specialists, P. xuthus, P. polytes, P. memnon, P. machaon and P. dardanus. Orthologous ORs or GRs in Papilio had highly conserved gene structure. Five Papilio specialists exhibited a similar frequency of intron lengths for ORs or GRs, but which was different from those in the generalist. Phylogenetic analysis revealed 60 orthologous OR groups, 45 of which shared one-to-one relationships. Such a single gene in each butterfly also occurred in 26 GR groups. Intriguingly, bitter GRs had fewer introns than other GRs and clustered into a large clade. Focusing on the two chemoreceptor gene families in P. xuthus, most PxutORs (52/58) were expressed in antennae and 31 genes in reproductive tissues. Eleven out of 28 foretarsus-expressed PxutGRs were female-biased genes, as strong candidates for sensing oviposition stimulants. These results indicate that the host range may not shape the large-scale expansions of ORs and GRs in Papilio butterflies and identify important molecular targets involved in olfaction, oviposition or reproduction in P. xuthus.

A novel method for extracting mutation points of acoustic emission signals based on cosine similarity

Mutation point extraction in acoustic emission (AE) signals is always a complex and challenging task since the mutation is often hidden in AE signals and with a short duration. This paper proposes a novel method based on cosine similarity (CS) to detect change points in AE signals. Disregarding the specific value of AE signals, the proposed method extracts the similarity features from the adjacent waveforms. Compared with traditional AE analysis and state-of-art methods, the proposed method performs better for extracting mutation points in an AE monitoring laser scanning experiment. A combination of a de-negative step and a linear normalization step is applied in the preprocessing procedure to efficiently eliminate the oscillation and vibration in CS calculation. Key parameters (window length and sampling frequency) are demonstrated to affect the mutation points extracting accuracy. The proposed CS method provides an alternative for mutation extraction in AE signals, and can be used in other practical applications.

Simulation of Droplet Formation in T‐Inlet Microchannels with Different Junction Angle

AbstractThe level set method was used to numerically simulate the droplet formation process in T‐junction microchannels with different junction angle. The effects of flow rate ratio, capillary number, and contact angle on droplet formation under different junction angles were discussed. The numerical simulation results show that the dimensionless length and generation frequency of microdroplets increase with the flow rate ratio. It was observed that the droplet transforms from the squeezing regime to the dripping regime when the capillary number Ca is ≥ 0.02. For Ca ≤ 0.04, the smallest droplet was generated in the microchannel with 120° junction angle. Finally, the results also indicate that the effect of the contact angle is discrepant at different junction angles.

Krill biomass estimation: Sampling and measurement variability

Krill are the subject of growing commercial fisheries and therefore fisheries management is necessary to ensure long-term sustainability. Krill catch limits, set by Commission for the Conservation of Antarctic Marine Living Resources, are based on absolute krill biomass, estimated from acoustic-trawl surveys. In this work, we develop a method for determining an error budget for acoustic-trawl surveys of krill which includes sampling and measurement variability. We use our error budget method to examine the sensitivity of biomass estimates to parameters in acoustic target strength (TS) models, length frequency distribution and length to wetmass relationships derived from net data. We determined that the average coefficient of variation (CV) of estimated biomass was 17.7% and the average CV due from scaling acoustic observations to biomass density was 5.3%. We found that a large proportion of the variability of biomass estimates is due to the krill orientation distribution, a parameter in the TS model. Orientation distributions with narrow standard deviations were found to emphasise the results of nulls in the TS to length relationship, which has to potential to lead to biologically implausible results.

Heel riser height and slope gradient influence the kinematics and kinetics of ski mountaineering-A laboratory study.

In ski mountaineering, equipment and its interaction with the exercising human plays an important role. The binding, as the crucial connection between boot and ski, must ensure safe fixation during downhill skiing and a free moving heel when walking uphill. Uphill, the binding offers the possibility to adopt the height of the heel (riser height) to personal preferences and the steepness of the ascent. This possible adjustment and its influence on various biomechanical parameters are the focus of this work. For this study, 19 male leisure ski mountaineers were tested on a treadmill, ascending at a fixed submaximal speed (3.9 ± 0.4 km·h−1) at 8, 16, and 24% gradient and with three heel riser heights, low (0 cm), medium (3.0 cm) and high (5.3 cm). The applied biomechanical measurement systems included a 3D motion capture system in sagittal plane, pressure insoles, a with strain gauges instrumented pole, spirometry and a comfort scale. Step length and step frequency were influenced by the riser height and the gradient (p ≤ 0.001). The high riser height decreased the step length by 5% compared to the low riser height over all tested gradients, while steps were 9.2% longer at the 24% gradient compared to the 8% gradient over all three riser heights. The high riser height revealed a force impulse of the pole 13% lower than using the low riser height (p < 0.001). Additionally, the high riser height reduced the range of motion of the knee joint and the ankle joint compared to the low riser height (p < 0.001). Therefore, advantageous settings can be derived, with the low riser height creating proper range of motion for ankle, knee and hip joint and higher propulsion via the pole at 8%, while higher riser heights like the medium setting do so at steeper gradients. These findings are in line with the conducted comfort scale. We would not recommend the highest riser height for the analyzed gradients in this study, but it might be an appropriate choice for higher gradients.

Back-Reflection in Resonant Fiber Optic Gyroscope and the Suppression Method

Backscattering and back-reflection are one of the main factors restricting the improvement of resonant fiber optic gyroscope accuracy. At present, most researches focus on backscattering. Due to the dependence on narrow linewidth laser, the interference of back-reflection light and the main light produces fluctuations in light intensity, which deteriorates the angle random walk of the resonant fiber optic gyroscope. This paper focuses on the back-reflection light outside the fiber ring resonator, taking the reflection on the end face of the photoelectric detector as an example, and simulates the influence on the detection noise of resonant fiber optic gyroscope. According to the frequency spectrum of intensity noise caused by back-reflection, a suppression method including length matching and frequency separation is proposed. The simulation and experimental results show that this method can effectively reduce the influence of back-reflection, and the angle random walk is improved by 6.06 dB with this method.

Microstructural features transformation at various temperature stages and multi-scale atomistic representations of calcined petroleum coke based on HRTEM

Calcined petroleum coke is a high-quality precursor for graphitic electrodes, and the heating temperature is an essential parameter for the key calcination process. Microstructural features (including lattice fringes length, stacking, orientation, and curvature) transformation at various temperature stages and multi-scale atomistic representations of the calcined coke were investigated by combining HRTEM lattice fringes analysis, XRD, XPS, XRF, mathematical function fittings, computational scripts, molecular dynamics relaxation, and DFT calculation. In the temperature range of 289 to 1873 K, the average lattice fringe length, total stacking frequency, 45° contribution, and curved fringe length frequency changed from 7.36 to 12.03 Å, 10.26 % to 50.63 %, 44.91 % to 98.71 %, and 58.74 % to 36.13 %, respectively. The variation patterns of most microstructure features fitted well with the quadratic function pattern in the temperature range of 298 to 873 K and the Logistic regression model in the temperature range of 873 to 1873 K. The trends of the fitted curves indicated that the microstructure of the calcined coke evolved to slight disorder below 873 K and significant order above 873 K. The mathematical equations of the fitted curves could reliably predict the value of the features at a given temperature stage. The typical molecular-scale (∼70 atoms) models, lattice-scale (3990 atoms) 3D model, and nano-scale (31909 atoms) 3D model of the calcined coke were constructed via the image-guided construction strategy with controllable order degree (utilizing Fringe3D and Packmol). The model data of the H/C ratio, functional groups proportion, trace metals content, true density, and structural features were similar to experimental data. The calculated FT-IR and XRD spectra validated the aromaticity and order degree of the representations.

General conditions for the resonance and cancellation of railway bridges under moving train loads

The objective of this paper is to elucidate the general conditions of resonance and cancellation for Bernoulli-Euler beam-based bridges subject to moving train loads. Firstly, the bridge's vibration shape is approximated based on the modal superposition method and Fourier series expansion. Then, the semi-analytical solution of the bridge vibrations under moving train loads is derived. After that, the general conditions of train-induced bridge resonance and cancellation are further derived, analyzed, and classified. In particular, cancellation is divided into three classes: case 1, case 2-I, and case 2-II. It is found that the resonance condition for simply-supported bridges is applicable to arbitrary Bernoulli-Euler beam-based bridges, while the cancellation conditions are related to the cancellation classes and modal characteristics of bridges. Finally, three examples are used to validate the semi-analytical solution of bridge vibrations as well as the general conditions of resonance and cancellation, including a simply-supported bridge, a continuous-beam bridge, and a long-span extradosed cable-stayed bridge. Besides, these examples show that for simply-supported bridges, both the resonance and cancellation should be considered, while for bridges with a long-span length or low fundamental frequencies, cancellation is more significant than resonance.

Reproductive traits of the round sardinella in the Canary Islands (Spain, NW Africa)

AbstractThe present study aims to investigate the reproductive biology of the small pelagic Sardinella aurita Valenciennes, 1847 in the Canary Islands, to enable its reliable assessment and advise on appropriate management measures for a fishing resource showing a declining trend in landings. Reproductive biology and sexual patterns of round sardinella were examined from monthly random samples of commercial catches landed by the artisanal purse-seine fleet. The landings' length frequencies, ranging between 9–32 cm (based on the total lengths, TL), were recorded from 2013–2019. The overall mean value of TL was 20.9 cm, with annual mean values between 20–22 cm, except in 2016 (TL = 19 cm). The overall sex ratio M:F was 1:0.92, with males significantly predominant. Sex ratios fluctuated as a function of size and month: females were more abundant in the larger length classes, as well as before and after spawning, whereas males were more abundant in the smaller length classes and during spawning. Based on gonad maturity stages and gonadosomatic index, round sardinella spawns during almost all the year, with a peak in January–February and a resting period during October–November. The length at first maturity was estimated at TL of 18.2 cm, notably smaller than the value obtained for the NW African coastal waters where the demographic structure in round sardinellas' landings is totally different.

Decision-making preferences in patients with advanced and recurrent endometrial cancer (502)

Objectives: To elucidate treatment decision preferences in women diagnosed with advanced or recurrent endometrial cancer. Methods: Women diagnosed with advanced or recurrent endometrial cancer at our institution were invited to participate in a combined survey and structured interview inquiring about decisionmaking preferences and quality-of-life (QOL). Participants completed the FACT-En, controlled preferences survey (shared decision-making survey), and completed questions inquiring about the importance of treatment decision preferences. The participants also underwent a structured interview to collect qualitative information on decision preferences. Descriptive statistics were performed on the data collected. Results: A total of 33 women participated in the survey/interview, reflecting an 89.2% participation rate. The median age of participants was 65.0 years, and 57.6% of participants self-identified as White, 33.3% as Black, and 15.1% as more than one race/other. Endometrioid adenocarcinoma was the most common histology (51.5%), followed by serous carcinoma (24.2%), carcinosarcoma (6.1%), clear cell carcinoma (6.1%), and one each of de-differentiated, mixed de-differenti- ated, and mixed endometrioid/clear cell carcinoma. Fifteen (45.5%) participants each had advanced endometrial cancer (Stage III or IV) and recurrent endometrial cancer, and the remaining three participants had a history of advanced or recurrent endometrial cancer. Among the participants, 29 (87.9%) were on treatment at the time of the study. Participants reported varying importance for ten different treatment considerations, displayed in Table 1. When participants were asked regarding the three most important treatment considerations of the ten options, participants reported physician recommendation (69.7%), treatment efficacy (69.7%), treatment side effects (60.6%), treatment schedule (33.3%), direct cost (18.2%), and <10% reported each of indirect cost, frequency of treatment monitoring, treatment length, and treatment modality. A majority of participants preferred a shared (collaborative) decision-making approach with their physician (n=19, 57.6%). In comparison, the remaining 11 (33%) preferred participating in a decision as an active decision-maker and three (9.1%) as a passive decision-maker. The median QOL score by FACT-En was 137 (IQR: 88) out of 172, and there was no association between shared decision-making preference and QOL score (p>0.05). Conclusions: Limited data exist about patient preferences in advanced, recurrent endometrial cancer. Our study described patient preferences about multiple treatment considerations. Patients with advanced or recurrent endometrial cancer prefer a collaborative, shared decision-making approach when deciding treatment for their cancer. In the setting of expanding treatment options in endometrial cancer, further work on measuring, identifying, and implementing patient preferences into clinical decision-making should be explored. Objectives: To elucidate treatment decision preferences in women diagnosed with advanced or recurrent endometrial cancer. Methods: Women diagnosed with advanced or recurrent endometrial cancer at our institution were invited to participate in a combined survey and structured interview inquiring about decisionmaking preferences and quality-of-life (QOL). Participants completed the FACT-En, controlled preferences survey (shared decision-making survey), and completed questions inquiring about the importance of treatment decision preferences. The participants also underwent a structured interview to collect qualitative information on decision preferences. Descriptive statistics were performed on the data collected. Results: A total of 33 women participated in the survey/interview, reflecting an 89.2% participation rate. The median age of participants was 65.0 years, and 57.6% of participants self-identified as White, 33.3% as Black, and 15.1% as more than one race/other. Endometrioid adenocarcinoma was the most common histology (51.5%), followed by serous carcinoma (24.2%), carcinosarcoma (6.1%), clear cell carcinoma (6.1%), and one each of de-differentiated, mixed de-differenti- ated, and mixed endometrioid/clear cell carcinoma. Fifteen (45.5%) participants each had advanced endometrial cancer (Stage III or IV) and recurrent endometrial cancer, and the remaining three participants had a history of advanced or recurrent endometrial cancer. Among the participants, 29 (87.9%) were on treatment at the time of the study. Participants reported varying importance for ten different treatment considerations, displayed in Table 1. When participants were asked regarding the three most important treatment considerations of the ten options, participants reported physician recommendation (69.7%), treatment efficacy (69.7%), treatment side effects (60.6%), treatment schedule (33.3%), direct cost (18.2%), and <10% reported each of indirect cost, frequency of treatment monitoring, treatment length, and treatment modality. A majority of participants preferred a shared (collaborative) decision-making approach with their physician (n=19, 57.6%). In comparison, the remaining 11 (33%) preferred participating in a decision as an active decision-maker and three (9.1%) as a passive decision-maker. The median QOL score by FACT-En was 137 (IQR: 88) out of 172, and there was no association between shared decision-making preference and QOL score (p>0.05). Conclusions: Limited data exist about patient preferences in advanced, recurrent endometrial cancer. Our study described patient preferences about multiple treatment considerations. Patients with advanced or recurrent endometrial cancer prefer a collaborative, shared decision-making approach when deciding treatment for their cancer. In the setting of expanding treatment options in endometrial cancer, further work on measuring, identifying, and implementing patient preferences into clinical decision-making should be explored.

Reassessing growth and mortality estimates for the Ordovician trilobite Triarthrus eatoni

AbstractA length–frequency sample (n = 295) from a fossil population of the Ordovician trilobite Triarthrus eatoni Hall, 1838, assembled and analyzed by J. L. Cisne in 1973 is here reexamined using methods of length–frequency analysis commonly used in fishery science and marine biology. Theoretical considerations and the empirical data at hand suggest that the growth of T. eatoni was not “linear,” but asymptotic, as is the growth of most Recent marine invertebrates. The parameters of the von Bertalanffy growth function (L∞ = 41 mm, K = 0.29 yr−1) suggest that T. eatoni, which apparently lived in a challenging environment, grew somewhat more slowly than the extant marine isopod Ceratoserolis trilobitoides (Eights, 1833), used here as Recent analogue to T. eatoni. This trilobite probably lived up to 10 years, rather than the suggested 4 years, and its mortality rate was 15%–20% per year rather than 30%–40% per year. These represent the first estimates of trilobite absolute growth characteristics using methods known to accurately model growth in extant water-breathing ectotherms. These provide a baseline for trilobite growth that can be used to make inferences about growth in other species. The approach used here may also be applied to other trilobites for which suitable length–frequency data exist.

Estimating growth from length frequency distribution: comparison of ELEFAN and Bayesian approaches for red endeavour prawns (Metapenaeus ensis)

Abstract Using length frequency distribution data (LFD) is cost-effective for estimating somatic growth in fish or invertebrates as length data are relatively easy to obtain. The recently developed R packages TropFishR and fishboot extend classic ELEFAN (Electronic LEngth Frequency ANalysis) programs and include more powerful optimization procedures and a bootstrap method for estimating uncertainties. Yet, the fundamental functions require users to provide search conditions (e.g. upper and lower limits for each parameter, length-class size, number of length-classes for the calculation of moving average), which can significantly affect the results. In this paper, we compare the ELEFAN approach with a Bayesian approach in analysing LFD, employing both standard and seasonal von Bertalanffy growth functions. We apply both approaches to a commercially valuable but poorly studied red endeavour prawn (Metapenaeus ensis) harvested in Australia's Northern Prawn Fishery. Sensitivity tests on ELEFAN confirm that any change in search settings would affect the results. Simulation studies on Bayesian growth models show that Linf and K can be accurately obtained even with modal progression of only one year-class and using non-informative priors. However, age information, including the theoretical age at length zero (t0), is difficult to estimate and requires LFD from multiple age classes and informative priors. The Bayesian models yield mean parameters of: Linf = 36.56 mm (carapace length), K = 2.74 yr–1, and t0 = -0.02 yr for the males, and Linf = 51.81 mm, K = 1.94 yr–1, and t0 = -0.02 yr for the females. Seasonal oscillation models fit the LFD better, but the improvement is small and the estimated season-related parameters have large variances.

Transverse vibration simulation of sucker rod string under normally distributed load caused by viscoelastic fluid in a curved wellbore

The sucker rod string is eccentric due to the effect of wellbore bending. When the sucker rod string undergoes an eccentric motion within the wellbore containing viscoelastic fluid in the polymer flooding pumping wells, it is subjected to an alternating normally distributed load caused by viscoelastic fluid (NDLVF). In this paper, it is pointed out that the alternating NDLVF acting on the sucker rod string is the excitation of the transverse vibration of the sucker rod string. Moreover, the coupling relationship between the NDLVF and the transverse vibration displacement of the sucker rod string is considered. Based on the elastic vibration theory, the mechanical and mathematical model of the transverse vibration of a sucker rod string under the NDLVF in the curved wellbore is established. Then, the Runge-Kutta method is used to solve the simulation model, and parameter sensitivity analysis is carried out. The simulation results show that: (1) the NDLVF can significantly affect the transverse displacement of the sucker rod string and the rod-tubing contact force, which is an essential excitation for the transverse vibration of the sucker rod string in the polymer flooding pumping wells. (2) Due to the NDLVF presence, the contact collision between the rod string and tubing string occurs more frequently, and the rod-tubing contact force is increased. (3) The NDLVF effect on the transverse vibration of the sucker rod string is most noticeable near the neutral point of the sucker rod string. (4) With an increase in the polymer concentration, stroke length, and stroke frequency, the transverse vibration of the rod string becomes stronger. The transverse vibration simulation model of the sucker rod string under NDLVF in a curved wellbore plays a guiding role when analyzing rod-tubing eccentric wear and optimal allocation of a centralizer in the polymer flooding pumping wells.

A Map of 3' DNA Transduction Variants Mediated by Non-LTR Retroelements on 3202 Human Genomes.

Simple SummaryDuring the transcription of non-LTR retroelements, such as LINEs and SVAs, the transcriptional termination signal at the 3′ end might be ignored by RNA polymerase. As a result, the transcription terminates at another downstream signal, creating a chimeric transcriptional readthrough. Termed 3′ DNA transduction, this process copies the 3′ flanking region along with the retroelement sequence to a new genomic locus, which influences the structure of the genome and occasionally possesses a functional impact. To discover putative non-LTR retroelement-driven 3′ DNA transductions, we analyzed the new dataset (n = 3202) of the 1000 Genomes Project. Our results indicate that 3′ transduction derived by non-LTR retroelements is a relatively common phenomenon in the human genome and that their discovery needs to be more appreciated in genome projects.As one of the major structural constituents, mobile elements comprise more than half of the human genome, among which Alu, L1, and SVA elements are still active and continue to generate new offspring. One of the major characteristics of L1 and SVA elements is their ability to co-mobilize adjacent downstream sequences to new loci in a process called 3′ DNA transduction. Transductions influence the structure and content of the genome in different ways, such as increasing genome variation, exon shuffling, and gene duplication. Moreover, given their mutagenicity capability, 3′ transductions are often involved in tumorigenesis or in the development of some diseases. In this study, we analyzed 3202 genomes sequenced at high coverage by the New York Genome Center to catalog and characterize putative 3′ transduced segments mediated by L1s and SVAs. Here, we present a genome-wide map of inter/intrachromosomal 3′ transduction variants, including their genomic and functional location, length, progenitor location, and allelic frequency across 26 populations. In total, we identified 7103 polymorphic L1s and 3040 polymorphic SVAs. Of these, 268 and 162 variants were annotated as high-confidence L1 and SVA 3′ transductions, respectively, with lengths that ranged from 7 to 997 nucleotides. We found specific loci within chromosomes X, 6, 7, and 6_GL000253v2_alt as master L1s and SVAs that had yielded more transductions, among others. Together, our results demonstrate the dynamic nature of transduction events within the genome and among individuals and their contribution to the structural variations of the human genome.

Population Characteristics of the Etheostoma pallididorsum Distler and Metcalf (Paleback Darter), a Narrowly Distributed Endemic in the Ouachita Highlands, Arkansas

Etheostoma pallididorsum (Paleback Darter) is endemic to the headwater reaches of 2 river systems in the Ouachita Highlands of Arkansas. Records of low abundance and habitat alterations have resulted in the species' imperiled conservation status and being petitioned for federal listing under the Endangered Species Act. The objective of this study was to conduct seasonal surveys across the Paleback Darter's distribution to better characterize growth, spawning patterns, and mortality using the seasonal von Bertalanffy statistic with an optimized electronic length frequency analysis (ELEFAN), as well as assess sex ratios throughout a calendar year to better inform future conservation management decisions for the species. We established seasonal survey collection sites at 4 localities and sampled with a backpack electrofishing unit and dip nets from January 2016 to October 2017. The study indicated relatively high abundance, based on catch per unit effort (CPUE), across all sampled localities throughout the duration of the study, with representation of the entire population from 3 age classes: 0, 1, and 2. Growth and coarse spawning patterns, based on the seasonal von Bertalanffy statistic, were comparable between the populations, suggesting similar and stable environmental factors throughout the distribution. Lastly, there was evidence of multiple spawn events occurring during winter and late spring or early summer that has not been documented for this species, warranting additional research. Collectively, this study, though narrow in scope and with limited data, suggest that the Paleback Darter populations assessed are not impaired. The endemic status and narrowly fragmented distribution of the Paleback Darter, however, still renders this species vulnerable to extirpation or extinction by stochastic events.

Growth and population characteristics of the Western King Prawn Penaeus latisulcatus (Kishinouye, 1896) from the southeastern Mediterranean off the Egyptian coast

Penaeus latisulcatus (Kishinouye, 1896) is considered one of the most economically important penaeid shrimp species in the Egyptian Red Sea. Recently, it appeared in the Egyptian Mediterranean catches. The present study is concerned with the estimation of growth, age and population characteristics of the non-indigenous P. latisulcatus collected between the months of July 2020 to June 2021 from the landing fishing center of Boughaz El-Maadiyah (Egyptian Mediterranean coast). A total of 2214 individuals were collected monthly. The results showed that the females to males ratio was 1:0.98. According to the Chi-square test, there was no statistically significant difference between the sexes (X2 = 0.181, df = 1, P > 0.05). The distribution of the length frequency showed that the females varied from 5.0 cm to 19.2 cm (TL) with a mean length of 11.73 ± 2.78 cm, while the males ranged from 5.3 cm to 17.1 cm (TL) with a mean length of 10.97 ± 2.06 cm. Positive allometry was detected for the total length-total weight relationship. The parameters of von Bertalanffy were L∞ = 20.56 cm, K = 0.99 yr−1 and to = −0.178 yr−1 for females, L∞ = 18.68 cm, K = 1.05 yr−1 and to = −0.172 yr−1 for males, and L∞ = 20.74 cm, K = 0.90 yr−1 and to = −0.196 yr−1 for the combined sexes. The expected age of females and males were 2.6 and 2.2 years, respectively. According to the parameters obtained, the current exploitation rate of the population of P. latisulcatus was estimated at Ecur. = 0.59. The results indicated that the population of P. latisulcatus is being highly exploited in Boughaz El-Maadiyah landing center (Egyptian Mediterranean coast). Hence, it is important to manage the P. latisulcatus shrimp resources in the studied area. Furthermore, similar studies are recommended for P. latisulcatus along the Egyptian Mediterranean coast to evaluate variations between populations in different fishing areas. Moreover, further studies are needed about the new aspects of the reproductive activity of this species as well as its aquaculture to estimate its growth rate experimentally.

Passive and Active Microrheology for Biomedical Systems.

Microrheology encompasses a range of methods to measure the mechanical properties of soft materials. By characterizing the motion of embedded microscopic particles, microrheology extends the probing length scale and frequency range of conventional bulk rheology. Microrheology can be characterized into either passive or active methods based on the driving force exerted on probe particles. Tracer particles are driven by thermal energy in passive methods, applying minimal deformation to the assessed medium. In active techniques, particles are manipulated by an external force, most commonly produced through optical and magnetic fields. Small-scale rheology holds significant advantages over conventional bulk rheology, such as eliminating the need for large sample sizes, the ability to probe fragile materials non-destructively, and a wider probing frequency range. More importantly, some microrheological techniques can obtain spatiotemporal information of local microenvironments and accurately describe the heterogeneity of structurally complex fluids. Recently, there has been significant growth in using these minimally invasive techniques to investigate a wide range of biomedical systems both in vitro and in vivo. Here, we review the latest applications and advancements of microrheology in mammalian cells, tissues, and biofluids and discuss the current challenges and potential future advances on the horizon.

«Цифровое поколение» осваивает чтение: влияние лингвистических параметров текста на глазодвигательные характеристики учеников 1–3-го классов

The level of reading literacy of the modern "digital generation" is an acute and significant topic. To explore this problem in dynamics it is necessary to objectively record the parameters of reading skills development in modern children. The article presents the results of an experimental study of the reading mechanism of elementary school students, performed using eye tracking. Fifty-three pupils in grades 1–3 of Moscow schools participated in the experiment, with real texts from Russian textbooks as stimulus material. Eye movements were recorded while reading texts from the screen, and after each text a comprehension question was asked. The results indicated a direct correlation between oculomotor characteristics and reading skill. From grade 1 to grade 3, the duration and number of fixations, amplitude duration, and reading time for both word and letter decreased, while the number of words with one or missing fixation increased. There was also a grade-independent effect of word length and word frequency factors on reading speed and oculomotor activity for students in all grades. Both factors had a significant effect on reading time, the average fixation duration was more sensitive to the frequency factor than to the word length factor, while word length alone influenced the first fixation duration.

Length-weight relationship and condition factor of Pacific whiteleg shrimp (Litopenaeus vannamei, Boone, 1931) cultured in polyethylene lined pond

Pacific whiteleg shrimp Litopenaeus vannamei (Boone, 1931) cultured worldwide with developments and revolutions in culture ponds like spread polyethylene liner over earthen ponds. The length-weight relationships in shrimp, Litopenaeus vannamei was evaluated cultured in polyethylene (PE) lined ponds from Bhimpore village of Surat district (Gujarat). For this purpose, 500 specimens from pond were collected during 2021 and their length and weight were recorded as per the standard methods. The length and weight were noted 11.488-15.581 (13.393±0.035) cm and 12.26-31.22 (19.613±0.162) gm during study. The noted length frequency distribution for length group A-23, for B-377 and for C-100. The recorded correlation coefficient (r2) of the shrimp were 0.633 (A), 0.780 (B), 0.809 (C) and 0.906 (pooled) noted. The growth constant or regression coefficient (b) was observed 2.541, 2.812, 3.531 and 2.997 for length group A, B, C and pooled population. The growth constant depicted that growth of shrimp was isometric (b=3.0) and normal. A mean Fulton&#39;s condition factor value noted 0.808 (±0.002). These findings are clearly indicating that the growth of studied shrimp was normal and good in the polyethylene (PE) lined pond.