Large Time Gap Research Articles

Relative effects of static and dynamic abiotic conditions on foraging behaviour in breeding Sandwich terns

Where and when animals forage depends on the spatio-temporal distribution and catchability of their prey. In dynamic environments, animals can repeatedly target areas that provide predictable availability of prey or may search for ephemeral conditions of high prey availability. However, how foraging behaviour is initiated in response to static versus dynamic environmental conditions is difficult to study, since both environmental data sources are often lacking. In this study, central-place foraging Sandwich terns were tracked using GPS loggers during foraging. Hidden Markov models showed that the probability of switching between transit and foraging was most strongly affected by the static variable sediment type. Wave period (a dynamic variable related to weather), salinity (a dynamic variable) and water depth (another static variable) affected the transition probability to a lesser extent. Cloud cover, wind speed and current speed were only included in lower ranked models. Air and water temperature were not included in any model. Consistent with the greater importance of static versus dynamic abiotic conditions, consistency between foraging trips of the same individual varied irrespective of tidal, diurnal or seasonal cycles, although trips made close in time within a season were slightly more similar than trips with a larger time gap. We suggest that Sandwich terns target broad areas with coarser sediments, where sandeels (Ammodytidae) are more common, and that weather variables may be related to prey visibility. Our study suggests that even in highly dynamic environments, static environmental variables may more strongly affect foraging behaviour of coastal seabirds than dynamic variables.

Spatio-temporal evolution of forest in Târgu Lăpuș, northern Transylvania, Romania, using Landsat satellite data

The use of remote sensing indices in order to obtain information for vegetation distributions, heath and patterns is a popular practice with applicability at different scales of detail. The present article presents an example of using the Normalized Difference Vegetation Index (NDVI) and Change Detection method to identify the spatio temporal evolution of forest area in Târgu Lăpuș city, northern Transylvania, Romania. NDVI method is applied at different NDVI threshold values such as 0.1, 0.15, 0.3, 0.45 and 0.6. For the analyzed area, an area of 1.56 km2 with forest gain and 3.59 km2 with forest loss was identified. The advantage of using this method is the large time gap for which it can be done, in our situation being an analysis for the period 1983-2020 so that we can identify the trend of evolution of areas occupied by forests in a city where spatially built it often extends uncontrollably, affecting the degree of compactness of the forests and implicitly their protection functions.

Experimental and numerical investigation on the dynamic characteristics of a lab-scale transcritical CO2 loop

Supercritical carbon dioxide (sCO2) Brayton cycle attracts much attention due to its high efficiency, compactness and low water consumption. In a sCO2 cycle, a transcritical CO2 (tCO2) dynamic looping is unavoidable during processes of startup, shutdown and unexpected conditions, which brings many challenges in the system design and operation due to the drastic physical property change of CO2 near the critical point, and its effects on the system dynamic characteristics are still not clear. In this study, we carry out experimental and numerical studies to explore the dynamic characteristics of a simplified tCO2 loop. The numerical model is developed by combining heat exchangers, a pump and a back-pressure valve with a detailed consideration of the coupled CFD and heat transfer processes. We validate the model by comparing the simulation results with the experimental data and obtain a small root-mean-square error (<3%). We investigate the system response and dynamic characteristics in the case studies, where the developed model has a higher accuracy in capturing the dynamic characteristics compared with the experimental sensors, and the change of ambient temperature resulted in a significant fluctuation of gas source pressure between 3.8 and 8.0 MPa. We also observe a pressure overdose of > 1.0 MPa in a short time with the frequency rising from 20 Hz to 50 Hz, which is about 40% of the target pressure change. We find a large acquisition time gap could provide stable results but may lost transient characteristics during the operation.

Opportunistic magnetotelluric transects from CSEM surveys in the Barents Sea

Summary Magnetotelluric (MT) data allow for electrical resistivity probing of the Earth's subsurface. Integration of resistivity models in passive margin studies could help disambiguate non-unique interpretations of crustal composition derived from seismic and potential field data, a recurrent issue in the distal domain. In this contribution, we present the first marine MT data in the Barents Sea, derived from industrial controlled-source electromagnetic (CSEM) surveys. We characterize data quality, dimensionality, depth penetration and elaborate an analysis strategy. The extensive MT database consists of 337 receivers located along 7 regional transects, emanating from ∼70,000 km2 of 3D CSEM surveys acquired for hydrocarbon exploration from 2007 to 2019. High-quality MT data are extracted for periods ranging from 0.5 s to 5000 s. The data show no apparent contamination by the active source nor effects related to large time-gaps in data collection and variable solar activity. Along receiver profiles, abrupt lateral variations of apparent resistivity and phase trends coincide with major structural boundaries and underline the geological information contained in the data. Dimensionality analysis reveals a dichotomy between the western domain of the SW Barents Sea, dominated by a single N-S electromagnetic strike, and the eastern domain, with a two-fold, period-dependent strike. 35 receivers show 3D distortion caused by nearby bathymetric slopes, evidenced by elevated skew values. We delineate geographical areas where the 2D assumption is tenable and lay the foundation for future MT modelling strategies in the SW Barents Sea. We performed 2D MT inversion along one of the regional transects, a ∼220 km-long, E-W profile encompassing a major structural high and sedimentary basin approaching the continent-ocean transition. The resistivity model reveals low crustal resistivity values (1–10 Ω.m) beneath the deep sedimentary basins, in marked contrast with high resistivity values (1000–5000 Ω.m) of the thick crystalline crust on the structural high. We interpret this abrupt lateral resistivity variation as a rapid transition from a thick, dry continental crust to a hyperextended and hydrated crustal domain. Integration of resistivity with seismic velocity, density and magnetic susceptibility models may further refine these structural models and the underlying tectonic processes in the SW Barents Sea margin. Our methodology is applicable globally where 3D CSEM surveys are acquired and has a large potential for harvesting new knowledge on the electrical resistivity properties of the lithosphere.

Tetris-inspired approach for generating tightly-packed repetitive schedules

Scheduling repetitive projects such as highways and High-rise buildings to meet strict deadlines is challenging, particularly when the repetitive units (sections/floors) are non-identical and resources are limited. In this case, conventional CPM/LOB schedules exhibit large time gaps, causing project delays. This paper proposes computational and geometrical enhancements to generate tightly-packed repetitive schedules, envisaged by the game of Tetris. The paper introduces novel procedures to overcome existing scheduling challenges: (1) revised computation to better determine tasks' delivery rates that meet deadlines; (2) formulation of mid-activity interruption time and mid-activity rate changes that synchronize task delivery rates; (3) multi-crew arrangement method, As-Soon-As-Possible, that better suits non-identical units; and (4) a simplified heuristic combining all procedures above to generate tightly-packed schedules with shorter durations. As presented in the paper through examples, the proposed techniques reduce the duration of complex repetitive projects using enhanced schedule computation and geometry rather than using expensive acceleration/optimization methods.

Administrative Responsibility for Committed Offenses in the Field of Family and Domestic Relations

On the basis of a comprehensive systemic analysis of legal phenomena, administrative liability for offenses committed in the field of family and domestic relations is considered. An analysis of the Law of Ukraine "On Prevention and Counteraction to Domestic Violence" and the Code of Ukraine on Administrative Offenses. It is noted that the legislation of Ukraine on administrative liability for offenses committed in the study area is a system of administrative tort rules. Analysis of the main components of administrative offenses in the study area showed that they encroach on the rights and health of citizens. The objective side of the offense of domestic violence is presented as a threat of violence, failure to ensure life or health; damage or destruction of property; coercive coercion to something; obscene swearing; disturbances of peace and quiet, expressed on the basis of family and domestic conflict in the place of residence or in places of common use of residential premises. The objective side of domestic violence is physical, psychological or economic, with the exception of sexual violence. Beatings remain a common illegal act in the field of family and domestic relations. Beatings committed in family and domestic relations pose a social danger to the family and require the application of appropriate administrative penalties. Prevention and cessation of offenses in the field of family and domestic relations should be carried out in a complex. Legal certainty of actions of the National Police, short terms of bringing to administrative responsibility, which do not have a large time gap between the illegal act and legal assessment, can ensure the inevitability of punishment, reduce the latency of beatings, prevent serious and especially serious crimes

Disparities in autism spectrum disorder diagnoses among 8-year-old children in Colorado: Who are we missing?

Although autism can be reliably diagnosed as early as 2 years of age, many children are not diagnosed with autism until much later. We analyzed data to determine why many of the 8-year-old children who resided in Colorado and were identified as having autism through a review of their health and/or educational records did not have a documented clinical diagnosis of autism and were not eligible for special education services under an autism eligibility. We found that children who did not have a documented clinical diagnosis of autism and were not eligible for special education services under an autism eligibility were more likely to be female, aggressive, and argumentative. They had a poorer quality of information in their records and were less likely to have had a developmental regression, sleep problems, or an autism screener or diagnostic measure in their records. These results suggest that the symptoms characteristic of autism among this group of children may have been attributed to another disorder and that clinicians may be able to recognize autism more readily in children with more functional impairment and those who experience a developmental regression. We also discovered that differences in symptom presentations among children who had a documented clinical diagnosis of autism and/or were eligible for special education services under an autism eligibility were associated with different ages at autism diagnosis.

The Effect of Youth Entrepreneurship Education Programs: Two Large-Scale Experimental Studies

Recent years have witnessed the worldwide growth of entrepreneurship education (EE) as entrepreneurship is regarded as the key driver of innovation and economic growth. Most extant studies on EE have focused on its impact on entrepreneurial intentions. However, the application of the same EE measurements for both adults and adolescents has long been criticized; the indices developed for potential adult entrepreneurs may not be suitable for young entrepreneurs, considering the large time gap before they enter the workforce. This study aims to develop appropriate indicators for the assessment of youth EE in Korea and to examine the effectiveness of youth EE. Two large-scale quasi-experimental studies were conducted with pre- and posttest matched-comparison groups for verification. This study suggests six common variables for measuring the impact of youth EE: opportunity discovery, opportunity exploitation, entrepreneurship, creativity capacity, social problem solving, and entrepreneurial intention. The analyses showed that all these indicators positively influenced youth EE. We also proposed practical suggestions for the development of EE programs.

Understanding blood and serum values of the agouti (Dasyprocta spp.): A rodent of the Neotropics with the potential to be domesticated

This short communication is intended to provide information on the blood and serum biochemical parameters of the agouti ( Dasyprocta spp.). Information on blood and serum biochemical parameters of this neo-tropical rodent is very scarce. Three agouti species from the Neotropical region were included in this report: Dasyprocta leporina , Dasyprocta fuliginosa and Dasyprocta prymnolopha . Several blood parameters were similar irrespective of the species, location, physiological state and method of restraint when blood was collected. Some of these parameters were red blood cell count, haemoglobin, haematocrit and mean corpuscular volume. Differences seen in some parameters were attributed to the differences in physiological state or environmental impact on the animal. The literature that was available showed a large time gap of approximately thirty (30) years in the reporting of blood parameters in the agouti. Early work was done in the mid-1970s and then recommenced in the mid-2000s. Some biochemical parameters such as triglycerides, amylase, chloride, sodium, potassium, bilirubin and uric acid were only recorded in the literature once and comparison of values was impossible. These parameters require further investigation which can be done in future studies. The dearth of information on the blood profile of the agouti gives justification for further research to be done in this regard as well as more detailed analysis of the effects that the environment and physiological states may have on haematological and biochemical parameters.

USE OF «KLIROVYE VEDOMOSTI» OF CHURCHES DURING THE RECONSTRUCTION OF THE PEDIGREES OF THE CLERGY

The article describes the history of emergence of «klirovye vedomosti» churches on the territory of Ukraine, finds out explores their information potential and peculiarities of using them in genealogical researches. «Klirovye vedomosti» are one the most important documentation types of parish record-keeping. Analyzing the archives materials and the published researches on the issue, the author investigates the process of formation and functioning of the clergy record-keeping. Along with legislative base of the emergence of «klirovye vedomosti», the special features of the realization of the law in daily life as well as the change of the form of the source since the XVIII century to the XIX century are retraced. «Klirovye vedomosti» were made up once a year in duplicate a church copy and a consistory one. Due to its systematic, regular keeping, mass character of coverage of the society they are an important source for reconstruction of pedigrees of the clergy. With their help it is possible to know out a family composition, the name, patronymic and surname (if it was designated), age of each member and relations inside the family. The lack of a large time gap allows with their help to determine the time of the marriage, the time of the death and also the quantity of born and deceased children during the period under study. The author considers that «klirovye vedomosti» must be applied first of all when there is not enough initial data to begin a genealogical research, that is exact dates of birth and names of the subject of the search are not know. This document is convenient to use in the case when the bloodline counts considerable number of representatives and has got numerous branching. The information potential of «klirovye vedomosti» gives an opportunity to research study pedigrees of representatives of the clergy.

An examination of the effect of the TESS extended mission on southern hemisphere monotransits

Context. NASA recently announced an extended mission for TESS. As a result it is expected that the southern ecliptic hemisphere will be re-observed approximately two years after the initial survey. Aims. We aim to explore how TESS re-observing the southern ecliptic hemisphere will impact the number and distribution of monotransits discovered during the first year of observations. This simulation will be able to be scaled to any future TESS re-observations. Methods. We carry out an updated simulation of TESS detections in the southern ecliptic hemisphere. This simulation includes realistic Sector window-functions based on the first 11 sectors of SPOC 2 min SAP lightcurves. We then extend this simulation to cover the expected Year 4 of the mission when TESS will re-observe the southern ecliptic fields. For recovered monotransits we also look at the possibility of predicting the period based on the coverage in the TESS data. Results. We find an updated prediction of 339 monotransits from the TESS Year 1 southern ecliptic hemisphere, and that approximately 80% of these systems (266/339) will transit again in the Year 4 observations. The Year 4 observations will also contribute new monotransits not seen in Year 1, resulting in a total of 149 monotransits from the combined Year 1 and Year 4 data sets. We find that 75% (189/266) of recovered Year 1 monotransits will only transit once in the Year 4 data set. For these systems we will be able to constrain possible periods, but period aliasing due to the large time gap between Year 1 and Year 4 observations means that the true period will remain unknown without further spectroscopic or photometric follow-up.

Timing the Evolutionary Advent of Cyanobacteria and the Later Great Oxidation Event Using Gene Phylogenies of a Sunscreen.

The biosynthesis of the unique cyanobacterial (oxyphotobacterial) indole-phenolic UVA sunscreen, scytonemin, is coded for in a conserved operon that contains both core metabolic genes and accessory, aromatic amino acid biosynthesis genes dedicated to supplying scytonemin's precursors. Comparative genomics shows conservation of this operon in many, but not all, cyanobacterial lineages. Phylogenetic analyses of the operon's aromatic amino acid genes indicate that five of them were recruited into the operon after duplication events of their respective housekeeping cyanobacterial cognates. We combined the fossil record of cyanobacteria and relaxed molecular clock models to obtain multiple estimates of these duplication events, setting a minimum age for the evolutionary advent of scytonemin at 2.1 ± 0.3 billion years. The same analyses were used to estimate the advent of cyanobacteria as a group (and thus the appearance of oxygenic photosynthesis), at 3.6 ± 0.2 billion years before present. Post hoc interpretation of 16S rRNA-based Bayesian analyses was consistent with these estimates. Because of physiological constraints on the use of UVA sunscreens in general, and the biochemical constraints of scytonemin in particular, scytonemin's age must postdate the time when Earth's atmosphere turned oxic, known as the Great Oxidation Event (GOE). Indeed, our biological estimate is in agreement with independent geochemical estimates for the GOE. The difference between the estimated ages of oxygenic photosynthesis and the GOE indicates the long span (on the order of a billion years) of the era of "oxygen oases," when oxygen was available locally but not globally.IMPORTANCE The advent of cyanobacteria, with their invention of oxygenic photosynthesis, and the Great Oxidation Event are arguably among the most important events in the evolutionary history of life on Earth. Oxygen is a significant toxicant to all life, but its accumulation in the atmosphere also enabled the successful development and proliferation of many aerobic organisms, especially metazoans. The currently favored dating of the Great Oxidation Event is based on the geochemical rock record. Similarly, the advent of cyanobacteria is also often drawn from the same estimates because in older rocks paleontological evidence is scarce or has been discredited. Efforts to obtain molecular evolutionary alternatives have offered widely divergent estimates. Our analyses provide a novel means to circumvent these limitations and allow us to estimate the large time gap between the two events.

Bimodal zircon ages from Natash volcanics (southeast Egypt) and the link between eruption mechanisms and Late Cretaceous tectonics

Trachyte plugs from the Natash volcanic field have been precisely dated using in situ U-Pb geochronology on zircon grains at ~93 Ma. Available zircon ages thus suggest that the overall volcanic history at Natash was probably shorter than previously estimated based on Rb-Sr and K-Ar ages, which are more sensitive to element mobility. Basaltic flows and trachyte plugs were produced by a largely synchronous, Upper Cretaceous volcanic activity that occurred in the Natash area at the onset of the extensional fracturing that preceded and accompanied the doming of the Afro-Arabian Shield. Extraction and eruption of volumetrically dominant basalts from deeper lithospheric levels were ruled by major NW-SE strike-slip faults, whereas both major and subordinate fault systems activated by successive tectonic pulses favoured the ascent of more evolved melts (i.e. trachytes and rhyolites) from shallow-level magma chambers. The study revealed also the presence of zircon xenocrysts in some trachyte plugs associated or not to magmatic zircon. These xenocrysts have pre-Cambrian ages (~681 Ma) matching those of zircons from basement rocks in the area (~700 Ma) and were most probably incorporated during the emplacement of trachyte plugs at shallow depths. The strictly bimodal ages recorded by zircons suggest a very large time gap (> 500 Ma) between the end of the Pan-African Orogeny and the onset of new tectono-magmatic activity in the Natash area.

Land cover classification in the tropics, solving the problem of cloud covered areas using topographic parameters

Optical remote sensing data has been extensively used since early seventies for mapping and monitoring land cover. But, cloud cover has always been hindering the optimal use of the data, especially in the tropical and temperate regions. Because of cloud cover, researchers are forced to use only cloud free images or generate a composite using data from different dates to fill in the cloud and cloud-shadow areas. It is not a problem if the filling image is from the same season and from the same year. If there is large time gap between the acquisition date of image with the clouds and that of the filling image it will have an effect on classification accuracy. In this paper, we describe an approach in land cover classification of areas covered by cloud and cloud shadows. We use the synergy of optical image classification, processing of SAR data taking advantage of its ability of penetrating clouds, and decision rules using terrain parameters. We hypothesize that surface roughness of different land cover types derived from processing of SAR data and in combination with other topographic parameters (slope and elevation) can be applied to classify areas covered by clouds and cloud-shadows. The method was applied in a case study in Mts. Wayang-Windu and Patuha areas, near Bandung in West Java, Indonesia. Landsat 8 OLI-TIRS, Sentinel-1 A C band and SRTM DEM data of the study area were obtained. Initial classification of the optical data was carried out using training samples and fuzzy classification. Class labelling was done by applying fuzzy c-means algorithm. The Sentinel-1 A C band data was processed to get surface roughness. Decision boundaries for surface roughness, terrain slope and elevation were generated for each land cover type, which were implemented in the classification of the areas covered by cloud and cloud shadows. The result shows that it is possible to solve the problem of cloud cover using terrain parameters.

Algorithm for diabetes risk evaluation from past gestational diabetes data.

Gestational diabetes mellitus (GDM) is defined as glucose intolerance that is diagnosed in pregnancy period, leading to possible complications for both mother and fetus during pregnancy. The aim of this study was to build an objective method to evaluate diabetes mellitus (DM) risk from past GDM data recorded 15 years ago and find a short list of most informative indicators. The dataset consists of demographic, lifestyle, clinical, genetic and pregnancy related information recorded 15 years ago. Due to the large time gap data are limited and have missing values (MVs). Follow-up tests were performed to see if DM or impaired metabolism has developed after pregnancy with previously diagnosed GDM. The research steps involve pre-processing data to evaluate MVs, finding most informative attributes and testing standard classification algorithms to combine in to most effective voting meta-algorithm. Initially the attributes and records with large number of MVs were rejected. A small percentage (2.04%) was imputed using regression based methods. The data set was prepared for two scenarios: classification in two classes (1-healthy; 2-impaired metabolism including DM) and three classes (1-healthy; 2-impaired metabolism; 3-DM). Voting meta-algorithm combining best algorithms of 21 from five different groups including Bayesian, regression, lazy, rule, and decision trees makes classification more objective and not depending on preferences. Relative frequency of occurrence (RFO) analysis of attributes combined with voting meta-algorithm helped finding optimal amount of attributes giving best possible classification result. The algorithm applied to two class data set with 12 selected attributes produced accuracy of 75.85 and AUC = 0.82 with standard error of 0.11. Similarly for three class dataset the 9 attributes were selected allowing to reach classification accuracy 63.77 and AUC = 0.76 with standard error of 0.1. Meta-algorithm based classification of limited anamnestic GDM related data for DM prediction is proving to be effective. Testing multiple algorithms and performing RFO analysis appears to be natural and objective way of selecting most informative attributes and evaluating their importance.

Fibre‐optic supported measurement methods for monitoring rock pressure

AbstractLike every civil engineered structure tunnels are subject to an ageing process. The reasons for the degrading of the condition are manifold: not fully completed stress redistribution, deterioration in the rock mass quality through long‐term exposure (creeping), weathering or dynamic loads and stresses, to name but a few. All this processes lead to a deformation of the surrounding bedrock and the lining.For a continuous monitoring of a tunnel condition the measurement of the deformation is necessary. Conventional methods are elaborate and time‐consuming and require almost always a shutdown of the tunnel for traffic. Therefore, an inspection is done selectively with large time gaps. A continuous condition assessment becomes hardly possible. Currently no robust method for permanent monitoring of tunnels exists. With a fibre optic measuring method many of these restrictions can be overcome. In the course of this research project, a novel and innovative measuring methodology has been developed to continuously and extensively measure rock deformations. The measurement results were evaluated performing laboratory tests. Subsequently, they were installed in the course of a field test at the Semmering Base Tunnel. With complementary technologies such as laser scanning, the measurement methodology could be verified for its applicability.

The associations of intimacy and sexuality in daily life: Temporal dynamics and gender effects within romantic relationships.

The experience of emotional intimacy is assumed to play a particularly large role in maintaining sexual desire and partnered sexual activity in romantic relationships of longer duration. It is unclear whether the effect of intimacy on sexual contact between partners is direct or indirect, via its impact on sexual desire. Baumeister and Bratslavsky suggested that a certain increment in emotional intimacy causes a greater increment in sexual desire in men than in women. In the present study, we aimed to test the mediating role of sexual desire between perceived intimacy and sexual partner interaction and the gender effect as hypothesized by Baumeister and Bratslavsky. Experience sampling methodology in the participant’s natural environment was used. At 10 quasi-random moments per day, during 7 consecutive days, 134 participants reported their feelings of emotional intimacy, sexual desire, and sexual activity. The direct effect of intimacy on sexual partner interaction was not significant, but an indirect effect via sexual desire was observed. The strength of the association between intimacy and sexual desire diminished over time, from the strongest effect when intimacy, sexual desire, and sexual activity were measured simultaneously to a very small, but significant effect at an average time lag of 3 hr. At still larger time gaps, no effects were found. Men reported a higher average level of sexual desire than women, but the strength of the link between (increases in) intimacy and sexual desire was not different between the genders. The present findings suggest that in both male and female partners in romantic, long-term relationships, higher levels of intimacy are associated with higher sexual desire, which is, in turn, associated with higher odds for partnered sexual activity to occur. The temporal association of increasing intimacy and subsequent sexual desire appears not to be different in women and men.

Super-Resolution for GaoFen-4 Remote Sensing Images

In this letter, the application of super-resolution (SR) techniques to GaoFen(GF)-4, which is the most advanced geostationary-orbit earth observing satellite in China, remote sensing images is investigated and tested. One of the shortcomings of the geostationary-orbit-based earth observing satellite is the limitation of spatial resolution. However, human beings never stop pursuing higher resolution in images. This is the first experiment of applying SR to a sequence of low-resolution (LR) images captured by GF-4 within a short time period. One of the barriers for applying SR to remote sensing images is the large time gaps between those LR image acquisition, because the reflection characteristic of the ground may change within the time period when those LR images were captured. However, GF-4 has the unique advantage of capturing a sequence of LR images of the same region in minutes, i.e., working as a staring camera from the point view of SR. The reconstructed high-resolution images of some regions in Beijing and Hainan are shown and evaluated in this letter. This letter demonstrates that the application of SR to geostationary-orbit-based earth observation data is feasible and valuable, and it has the potential to be applied to the images acquired by all other geostationary-orbit-based earth observing systems.

Detecting Password File Theft using Predefined Time-Delays between Certain Password Characters

This paper presents novel mechanisms that effectively detect password file thefts and at the same time prevent uncovering passwords. The proposed mechanism uses delay between consecutive keystrokes of the password characters. In presented case, a user should not only enter his password correctly during the sign-up process, but also needs to introduce relatively large time gaps between certain password characters. The proposed novel approaches disguise stored passwords by adding a suffix value that helps in detecting password file theft at the first sign-in attempt by an adversary who steals and cracks the hashed password file. Any attempt to login using a real password without adding the time delays in the correct positions may considered as an impersonation attack, i.e. the password file has been stolen and cracked.

159 Effect of Commercial Embryo Holding Medium on Development and Quality of Immature Bovine Oocytes

Bovine in vitro embryo production following ovum pick-up (OPU) in the field is hampered due to large time gaps between first and last OPU sessions. As oocytes will start immediate maturation, scheduling further manipulations makes the laboratory work laborious. There is a need for an easy and low-cost method that conserves the oocytes with full developmental capacity and allows scheduling laboratory work. In this regard, a commercial embryo holding medium (EHM; Syngro®; Bioniche Inc., WA, USA) was evaluated for conserving immature oocytes. Bovine immature oocytes (n = 2160) were collected from slaughterhouse animals by follicle aspiration and grouped per 60 and stored in 1 mL of EHM in 1-mL sterile glass osmometer tubes. Then, different temperatures [4°C, room temperature (RT), and 38.5°C] and different storage times (6, 10, 14 h) were assessed. After storage, oocytes were matured in TCM-199 supplemented with epidermal growth factor and gentamycin for 22 h. Fertilization was performed and zygotes (n = 1786) were cultured per 25 in 50 µL of SOF medium supplemented with 0.4% BSA and insulin, transferrin, and selenium. Control groups were included: immature oocytes (n = 1080) were not stored in EHM but immediately matured; fertilized and zygotes (n = 896) were cultured. Further, differential apoptotic staining was performed on a random subgroup of blastocysts to assess quality. Generalized fixed effect models were computed using R studio. Storage for 6 h showed a decrease in cleavage and blastocyst rate at 38.5°C (50 ± 3.9%; 11 ± 1.8%) compared with the control (78 ± 3.0%; 36 ± 2.8%). When increasing storage time, 38.5°C was not included; here, 4°C had a lower cleavage and blastocyst yield (47 ± 2.9%; 20 ± 3.3%) compared with the control (75 ± 2.5%; 41 ± 4.6%). For both 6 and 10 h, storage at RT resulted in similar cleavage (76 ± 3.4%; 74 ± 2.6%) and blastocyst rates (35 ± 2.7%; 40 ± 4.5%) as the control (P &gt; 0.05). However, increasing storage to 14 h at RT decreased cleavage (61 ± 2.8%) and blastocyst yield (26 ± 2.5%) compared with the control (78 ± 2.4%; 39 ± 2.8%; P &lt; 0.05). Evaluating embryo quality in all groups, no significant differences were found for any holding time or temperature of the EHM. To simulate OPU settings, EHM was also tested in 38 small groups of 10 immature oocytes that were subsequently matured, fertilized, and cultured. Based on the previous results, EHM storage was performed for 6 and 10 h at RT. Blastocyst development was not different between RT (19.8 ± 3.5%; 18.8 ± 3.6%) and the control (20.6 ± 3.6%; 18.3 ± 3.4%; P ≥ 0.05). To conclude, a commercial EHM can be used to conserve immature bovine oocytes without losing developmental capacity. Storage is recommended for no longer than 10 h and at RT in EHM. It opens new perspectives for practitioners, because this method is simple and low-cost; moreover, the start of maturation and subsequent in vitro embryo production process can be scheduled to avoid evening or night work at the laboratory.