Patterns of otter Lutra lutra road mortality in a landscape abundant in lakes

In order to reduce otter (Lutra lutra) road mortality and to predict accident sites, we assessed the localities of traffic accidents involving otters in the Uckermark County, Brandenburg, Northeast Germany. Eighty-eight otter accident sites from the years 1990 to 2003—as recorded by the Naturschutzstation Zippelsförde des Landesumweltamtes Brandenburg (Brandenburg State Office for Environment)—were categorised according to traffic and road patterns, otter habitat suitability, as well as presence and type of watercourse crossings. From these numerical data, we compiled a list of characteristics to identify other potentially dangerous sites where otter road traffic accidents are likely to occur using a geographic information system. With a principal component analysis, we categorised three groups of accident sites. Firstly, most otter road accidents were located close to either one or two lakes. Secondly, otters were frequently killed at places where no body of water occurred within a distance of 200 m to the road. Thirdly, and in contrast to other locations, in the Uckermark County, fewest accidents happened where a road crossed a watercourse. Mitigation measures were suggested and discussed for the recorded and potential accident sites.

     

Orientation by the Bat Phyllostomus discolor (Phyllostomidae) on the Return Flight to its Resting Place

Bats have a well-developed spatial memory, which enables them to navigate even when the conditions are extremely unfavourable for orientation. However, if they were to adhere too strictly to a flight path planned from memory and independent of exteroceptive control, they would be in danger of colliding with unexpected obstacles. In the experiments described here, Phyllostomus discolor that had familiarized themselves with an octagonal flight arena developed a clear preference for certain resting sites and were able to fly to these sites without recourse to external orientational cues. Proximal and distal cues were ruled out separately, by rotating the direction in which the bats started out within the arena or by rotating the entire arena in the room. Furthermore, by marking the preferred site with a visible identifier it was shown that even when additional aids to orientation are available, the bats do not make use of them. On the other hand, all the bats tested responded immediately to a reduction of the landing area, demonstrating that they are capable of incorporating exteroceptive information into the orientation process in certain circumstances.     

The viability and germination characteristics of exhumed Solanum mauritianum seeds buried for different periods of time

The site, depth and duration of burial significantly influenced the viability and state of dormancy of Solanum mauritianum seeds. Burial at a depth of 15 cm was most effective in reducing the level of conditional dormancy. Secondary dormancy was not induced at any of the environmental (burial) sites when seeds were maintained at 15 cm, where light and temperature fluctuations were minimal. When buried at 4 cm or maintained on the soil surface secondary dormancy was induced, particularly at the inland sites where environmental conditions such as temperature and moisture were more extreme. Conditional dormancy could generally be overcome by incubating seeds at 15/30 °C in the light, even after prolonged burial at unfavourable germination conditions. Gibberellic acid (500 mg l^–1) was very effective in breaking secondary dormancy of seeds induced by storage under unfavourable conditions after burial. These results have important implications for the control of this week in commercial forests.     

The mosquitoes of eastern Tennessee: studies on abundance,habitat preferences,and host‐seeking behaviors

A significant increase in the number of reported cases of La Crosse virus (LACV) infections in eastern Tennessee has occurred in the last ten years. The objective of this study was to determine the abundance and habitat preferences of the potential vectors of LACV in this region. Adult host‐seeking mosquitoes were collected using CO₂‐baited CDC light traps and a series of human‐landing catches in eastern Tennessee from 2004 to 2006. A total of 4,200 female mosquitoes of 23 species was collected by CO₂‐baited CDC trapping at ten sites during the study period. Aedes albopictus (Skuse) was the most abundant mosquito collected at all sites and vegetation types, with the ratios of total Ae. albopictus to Ae. triseriatus (Say) females collected being 2.1:1 in 2004, 3.8:1 in 2005, and 4.9:1 in 2006. Ten species were collected during a series of human‐landing catches made at four different sites; one probable and three confirmed case sites of LACV infections, totaling 528 female mosquitoes. Aedes albopictus was the most abundant species collected, with a 4:1 ratio of Ae. albopictus to Ae. triseriatus females. Aedes albopictus exhibited two clear peaks of “landing” activity, one in the early morning and one in the late afternoon or early evening. Simple and multiple regression analyses of the predictors of the number of mosquitoes collected showed that populations of Ae. albopictus were three times more likely to be collected overall than Ae. triseriatus. Species (Ae. albopictus), vegetation (residential), and the previous cumulative precipitation for the four weeks prior to collection were significantly (P < 0.05) associated with the number of mosquitoes collected by CO₂‐baited CDC trapping. Aedes albopictus was also more likely to be collected than Ae. triseriatus at confirmed cases of LACV infections.     

A comparison between back squat exercise and vertical jump kinematics: implications for determining anterior cruciate ligament injury risk

Women are up to eight times more likely than men to suffer an anterior cruciate ligament (ACL) injury, and knee valgus is perhaps the most at-risk motion. Women have been shown to have more knee valgus than men in squatting movements and while landing. The purposes were to investigate whether a relationship exists between lower-extremity frontal plane motions in squatting and landing, whether gender differences exist, and whether squat or hip abduction strength relates to knee valgus while landing. Eleven collegiate Division III soccer players and 11 recreationally trained men were tested for maximal vertical jump height and for squat and hip abduction strength. On the second day of testing, subjects performed light (50% one repetition maximum) and heavy (85%) squat protocols and three landings from their maximal vertical jump height. Pearson's product-moment correlation coefficients and a 2 x 10 factorial analysis of variance with t-test post hoc comparisons (p 相似文献   

Incidence of near accidental drowsing in locomotive driving during a period of rotation.

The incidence of drowsings as a cause of near traffic accidents was studied on the basis of daily recordings or near accidental events by 288 locomotive drivers during a rotation period of 2-3 weeks. Of 198 near accidents reported during 2,290 trips, 34 cases, or 1,5 cases per 100 trips, were operation missess involving drowsing or strong drowsiness. Improper operation due to drowsing occurred at a certain rate for any group of drivers, irrespective of the type of train, running sections, weather, and other operative conditions such as train delays, whereas 117 cases of danger caused by unforeseen obstacles on the track were related to site characteristics, and 47 cases of other disorders were frequent in unusual operative conditions such as arrival-departure, poor signal display, wrong instructions, or equipment failure. Thus continued driving under ordinary track conditions at a more or less constant speed was likely to induce drowsiness under the dominant influences of fatigue and time of the day; 79% of such cases occurred between midnight and 6 a.m. Most drowsings on the second night appeared during the first 2-4 hr of duty. Effects of monotony and insufficient rest were discussed in relation to recurrent fluctuation in vigilance.     

The relation between wave exposure and distribution of emergent vegetation in a eutrophic lake

SUMMARY 1. Maximum water depth penetration and changes in horizontal distribution during 39 years of the emergent vegetation in a eutrophic lake in southern Sweden were investigated.
2. The capacity of the emergent vegetation to penetrate into deeper water areas was found to be higher at wave exposed than al sheltered sites.
3. Differences in biomass and biomass allocation of the dominant speeies. Phragmites australis , between an exposed and a sheltered site suggest that horizontal expansion towards deeper water at sheltered sites is limited by unfavourable substrate conditions.     

Extent and distribution of tibial osteochondral disruption during simulated landing impact with axial tibial rotation restraint

Post-traumatic knee osteochondral injuries are often coupled with anterior cruciate ligament (ACL) injury mechanisms during landing. However, it is not well understood whether restraining axial tibial rotation during landing would influence the extent and distribution of osteochondral disruption. Using ski landing as an example, this study subjected knee specimens to simulated landing impact without and with axial tibial rotation restraint, and investigated the extent and distribution of osteochondral disruption at the tibial plateau. Twenty-one porcine knee specimens were randomly divided into three test conditions, namely: (1) control, (2) impact only (I), and 3) impact with restraint (IR). Simulated landing impact was applied to the specimens based on a single 10 Hz haversine. Osteochondral explants were obtained from anterior, middle and posterior regions of medial and lateral tibial compartments. The extent of cartilage and trabecular disruption in these explants was examined based on histology, SEM and microCT. Only specimens in unrestrained condition incurred ACL failure upon impact. Restraining axial tibial rotation during simulated impact generally inflicted cartilage damage and deformation, and further caused trabecular disruption. Axial tibial rotation restraint did not necessarily restrict anterior tibial translation, as indicated by the presence of relative posterior femoral translation and osteochondral disruption at anterior–posterior tibial regions. While the results obtained in the current study may not be completely translatable to human models, there is likelihood that restraining axial tibial rotation during landing may help to prevent ACL failure, but will also induce osteochondral disruption in most tibial regions.     

Endogenous endonuclease hypersensitive sites in Schizosaccharomyces pombe chromosomes

A novel method was used to characterize the long range susceptibility of Schizosaccharomyces pombe chromosomal DNA to endogenous endonuclease cleavage. Analyses of pulsed field gel experiments revealed two periodicities in the distribution of endogenous endonuclease hypersensitive sites. Endonuclease cleavage sites occurred, roughly at 30–50 kilobase pairs (kb) intervals under physiological conditions (25 mM KCl). At higher salt concentrations (250 mM KCl or 0.2 M and 0.9 M NaCl), endonuclease hypersensitive sites occurred at 200–300 kb intervals. Endonuclease hypersensitive sites in different chromosomal regions were monitored during different stages of the cell cycle. DNA sequencing around the endonuclease hypersensitive sites revealed the presence of clusters of A+T-rich motifs, autonomously replicating sequences (ARSs) in sequences (a characteristic of the scaffold-associated regions (SARs) and the presence of a CTG trinucleotide at most sites.     

Generating Customized Transgene Landing Sites and Multi-Transgene Arrays in Drosophila Using phiC31 Integrase

Transgenesis in numerous eukaryotes has been facilitated by the use of site-specific integrases to stably insert transgenes at predefined genomic positions (landing sites). However, the utility of integrase-mediated transgenesis in any system is constrained by the limited number and variable expression properties of available landing sites. By exploiting the nonstandard recombination activity exhibited by a phiC31 integrase mutant, we developed a rapid and inexpensive method for isolating landing sites that exhibit desired expression properties. Additionally, we devised a simple technique for constructing arrays of transgenes at a single landing site, thereby extending the utility of previously characterized landing sites. Using the fruit fly Drosophila melanogaster, we demonstrate the feasibility of these approaches by isolating new landing sites optimized to express transgenes in the nervous system and by building fluorescent reporter arrays at several landing sites. Because these strategies require the activity of only a single exogenous protein, we anticipate that they will be portable to species such as nonmodel organisms, in which genetic manipulation is more challenging, expediting the development of genetic resources in these systems.     

Optimal stopover decisions under wind influence: the effects of correlated winds

Wind speed and direction have a significant effect on a flying bird's ground speed. Migrants are therefore expected to be sensitive to wind conditions and this should have consequences for optimal strategies of stopover and refuelling. Based on an earlier model of time-minimizing migration which includes wind condition, we investigate the consequences of the temporal correlation of wind conditions. Day-to-day changes in wind conditions are modelled with a two-state Markov process and an expression for the expected speed of migration is derived. The policy of the migrants is described by two parameters: a day t(g) when the birds start to leave whenever favourable conditions occur and a later day t(b)when they leave even in unfavourable winds. The model predicts that in most cases departures should be close to the date which is predicted by a wind-free deterministic model and that the birds should never leave without wind assistance. Only if the probability that the condition remains the same on the following day is close to 1 should the birds leave even in unfavourable conditions shortly after the deterministic optimal date. If the transition matrix is highly asymmetrical, i.e. if it is very probable that unfavourable conditions remain and that favourable conditions will change into unfavourable, then the birds are predicted to start using good winds several days before the deterministic optimal date. An analysis of six years of wind data from two sites in Sweden shows that wind directions on successive days are in fact correlated in all years.     

Lower extremity function in terms of shock absorption when landing with unsynchronized feet

The purpose of this study was to clarify the lower extremity function in terms of the shock absorption during unsynchronized-foot landings. The characteristics of the supination and pronation in the ankle joint at landing were investigated, assuming that the measurements of the impact force on the body could be demonstrated by the changes that occurred during 3 different landing motions: -unsynchronized-foot landings, synchronized-foot landings, and one-foot landings. Subjects jumped to the floor from 10-cm footstools 3 times for each type of landing. For the synchronized-foot landing, the rear foot angle was 92.2 degrees at the start of landing and did not change significantly from landing start to 100 msec. For the one-foot landing, rear foot angle was 95.1 degrees at the start of landing and decreased rapidly to 87.1 degrees by 75 msec, and then increased rapidly to 90.8 degrees by 140 msec. For the unsynchronized-foot landing, the rear foot angle was 93.8 degrees at the start of the landing, decreased rapidly to 88.0 degrees by 75 msec, and then increased rapidly to 89.9 degrees by 115 msec.It was clarified that the lower extremity function for the shock attenuation during landing with the unsynchronized-foot was similar to that with one-foot landings, and the lower extremity function for supporting the body after another foot landing was similar to that after the synchronized-foot landings in this study.     

Snowmobile-related deaths in Ontario: a 5-year review.

OBJECTIVES: To investigate the demographic characteristics and circumstances surrounding fatal snowmobile accidents in Ontario, to examine the risk factors and to observe any fatality trends over the study period. DESIGN: Case series. PATIENTS: All 131 people who died accidentally while operating a snowmobile in Ontario from 1985-86 to 1989-90. Records were obtained from the chief coroner''s office; registration data were obtained from the Ministry of Transportation. RESULTS: Although the absolute number of deaths increased each year, owing to a rapid increase in the number of registered snowmobiles, the risk of death from snowmobile accidents remained relatively constant. Deaths occurred most frequently in northeastern Ontario. Youths and men predominated among the victims. Fatal accidents occurred more often on lakes (in 66% of the cases in which this information was known) than on roads (in 26%) or trails (in 8%). Weekend fatalities predominated, and deaths occurred most often during times of suboptimal lighting (from 4 pm to 8 am). The driver was killed in 84% of the cases in which the person''s role was known. Alcohol use before death was implicated in 69% of the cases, the level exceeding the Ontario legal limit in 59%. CONCLUSION: Snowmobile-related deaths result from factors that are generally avoidable. Strategies need to be instituted to reduce the rate of these events.     

THE VISIBLE MIGRATION OF RAPTORS OVER THE MALTESE ISLANDS

Whilst the large migrations of raptors at the Bosphorus and at the Straits of Gibraltar have been documented in some detail, the movements which take place across the Mediterranean itself have been neglected. This paper reports observations of the visible migration of raptors over the Maltese Islands during 1969–73. The largest numbers of raptors were recorded both in spring and autumn during contrary winds or overcast conditions. Normally very few were seen before the early afternoon at either season, in spite of the much shorter minimum sea-crossing in autumn. Large passages occurred in winds with easterly or westerly components. It is therefore concluded that eastward drift does not greatly affect the numbers seen in Malta, as had been suggested by De Lucca (1969); rather that most influxes occurred in the late afternoon during unfavourable meteorological conditions. At other times most migration was probably above the visible range. The number of raptors observed on passage in the Maltese Islands was small compared with movements at the Bosphorus or at Gibraltar. Nevertheless, the numbers of the narrow-winged species (i.e., Ospreys, harriers and falcons) compare favourably with records at the narrow crossings. The only large soaring species commonly seen in Malta was the Honey Buzzard. Evidence is presented which suggests that the volume of Honey Buzzard migration across the central Mediterranean may be much larger than was formerly realized.     

Escape behaviour in blue‐winged grasshoppers,Oedipoda caerulescens

Blue‐winged grasshoppers Oedipoda caerulescens (Linnaeus, 1758) are commonly found in flat, open, unprotected areas. In the event of immediate danger, they leave their camouflaged position and jump away at the last moment. The present study conducted in a flight arena shows that, despite jumping at short notice from a crouching position, the grasshoppers achieve the correct timing for an optimal leap. If both compound eyes are blinded and the animals are stimulated by touch to execute an unprepared jump, the take‐off of the flightless nymphs is delayed, and adults are delayed in raising their wings; the animals tumble backward during the leap (in the case of adults, if they do not open their wings). This is a result of the unprepared take‐off position; because the entire length of the hind legs cannot be used for acceleration, the body is rotated backward. However, the escape path is not ultimately affected because, in the air, physical processes compensate for the unfavourable starting conditions. In addition, no disadvantage is evident upon landing. In each case, a hook landing was completed safely (i.e. the grasshopper landed and swung round to face the direction it had come from). The impact force is reduced and the grasshopper stabilizes itself by rotating from a forward to a backward position, immediately after the first contact with the ground. The hook landing also serves to confuse the potential attacker, and the disappearance of the bright blue hind wings of the adult makes it difficult for predators to shift quickly enough to a different kind of search to relocate their prey. In conclusion, the present study shows that the escape behaviour of blue‐winged grasshoppers is adapted to extremely short escape distances.     

Simulation of phytomass productivity based on the optimum temperature for plant growth in a cold climate

During long-term monitoring (more than 20 years) of the hydrologic regime at 20 mountainous sites in the Czech Republic (altitude 600–1400 m a.s.l.; vegetation season April-September; mean air temperature 8–10°C; mean total precipitation 400–700 mm; mean duration of sunshine 1100–1300 hours; mean potential transpiration 200–250 mm) it was found that plant temperature does not rise above about 25°C when plants transpire. According to the ecological optimality theory, the phytocenosis that is able to survive unfavourable conditions and produce the biggest amount of phytomass will prevail at sites occurring in long-term stable natural conditions. Simulation of phytomass productivity based on the optimum temperature for plant growth showed that plants with an optimum leaf temperature of about 25°C can survive the unfavourable conditions and produce the largest amount of phytomass at the site studied in the long-term.     

Zooplankton (Cladocera, Ostracoda), Chironomidae and other benthic faunal remains in sediment cores from nine North African wetland lakes: the CASSARINA Project

Palaeolimnological studies were carried out on sediment cores from nine North African wetland lakes. The lakes represented a variety of habitats ranging from freshwater to mixohaline conditions and with and without direct connections to the sea. Sediment cores were examined for records of recent environmental change during the 20th century period. Faunal remains analysed in the sediments included those of Cladocera, Ostracoda, Chironomidae, Mollusca and, at the sites with marine connections, Foraminifera. Cyprideis torosa littoralis was the most common ostracod, occurring in sediments from the seven sites linked with the sea and also in brackish water Sidi Bou Rhaba. In acid Megene Chitane ostracods were scarce, being represented by a single species (Cypria ophtalmica). Candona neglecta completely disappeared at two sites (Sidi Bou Rhaba and Bokka) during the 20th century. Of the Cladocera, Chydorus sphaericus was common in the moderately mixohaline sites and but Heterocypris salina occurred only where marine salinities were occasionally achieved (in Zerga, Ichkeul and Korba). Microinvertebrate assemblages in the Nile Delta lake cores and to a less extent in Zerga showed a clear response indicative of more fresher conditions occurring during the latter part of the 20th century. However the freshening trend began prior to construction of the Aswan High Dam (mid 1960s).With the exception of the most saline site (Korba), microinvertebrate communiuties at all the CASSARINA sites have experienced major disturbances during the 20th century. Changes in freshwater availability associated with increased human usage of water resources is perceived as a major factor regulating the abundance and occurrence of aquatic microinvertebrate species at these sites     

Life history and population dynamics of Atriplex triangularis

The dynamics of a population of the stoloniferous Potentilla anserina was studied during four years. The mortality of established ramets followed a log-linear pattern superimposed on a seasonal fluctuation with an increased mortality during the period of vegetative spread. The major external mortality factors were unfavourable weather conditions such as drought and freezing. The turnover rate of the population was slow (31.6 yr). Vegetative spread dominated the recruitment to the population. Seedlings occurred but were exposed to a much higher mortality than vegetative daughter ramets. The juvenile period of seedlings is at least 4 yr in the field. This contrast to vegetative daughter ramets which are potentially flowering and stoloniferous the year after they are established, even if age affects both reproduction and vegetative spread. The density of most of the population is below the level where intraspecific regulative effects operate. However, in very dense stands both stolon and flower production were negatively density dependent.Nomenclature follows Lid (1974), Norsk og Svensk Flora, 2nd ed. Oslo.I am indebted to Lenn Jerling, Peter Torstensson, Anders Telenius and Gudrún Jónsdóttir for their help, and inspiring criticism throughout this study.     

Aspects of the bionomics of hematophagous symbovine dipterans in a hyper-infested rangeland of Ngaoundere (Adamawa-Cameroon)

A cattle exposure trial was carried out in an experimental cattle farm located in Galim near Ngaoundere. Observations were made from October–November 2016 and January 2017. Exposure commenced in the morning (8 h) and ended in the night (20h). The observed number of the different boophilic insect-groups was: Stomoxys (17,453), culicids (8925), Simulium (293), Chrysops (74) and Tabanus (34). Stomoxys (921.35) recorded the highest overall observed daily landing rate (ODLR) during the first survey-round (October–November 2016) and 740.85 during the second survey-round (January 2017) as compared to other hematophagous insect-groups observed. The preferred landing spots for most of the hematophagous insects were legs and belly regions, but Tabanus were also frequent around the head region. Brown colored cattle attracted Simulium, Chrysops, culicids and Stomoxys, but black animals were preferably attacked by tabanids. Cattle were mostly attacked in the overnight parks though there was no statistically significant difference (P?0.05). Two observed daily landing peaks (8 h–10 h and 16 h–18 h) were noticed for all biting fly-groups and was influenced by weather variables. The most frequent physical defense actions against landing flies by cattle was tail flicking. Such actions differed with survey-period, micro-ecosystems and color coat of cattle. Diurnal physical defense mechanism rhythms of cattle showed that head shaking was mostly used between 10 h–12 h and 16 h–18 h, but tail flicking and foot stamping only occurred between 13 h–15 h. There was a strong positive and significant correlation (r = 0.243, P < .001) in defense reactions and fly counts.     

The daily pattern of autumn bird migration in the northern Sahara

The temporal pattern of migration by passerine birds during the night, and their arrival during the day at the Egyptian coast and in the northern Sahara Desert was investigated. The mean direction of nocturnal migration at the coast was south-southeast, while at all desert sites it was south-southwest.
Birds arrived at the Egyptian coast only during the second half of the night which is explained by the fact that no birds could have taken off from the Mediterranean Sea. At least some of the birds landed at the coast where they spent the day before taking off shortly after sunset. These birds passed the desert sites at the expected time of day assuming a ground speed of 18 m per second. However, the origin of the birds passing the desert sites early at night is unclear. They must either have spent the day in the desert north of the study sites or they had overflown the Egyptian coast in the afternoon without landing.
The landing of birds during the day at the desert sites was bimodal. This pattern of arrival is explained either by some birds having landed at the Egyptian coast in the early morning before continuing, or by deteriorating conditions later in the day during flight or when resting in the desert, that obliged them to seek shelter at the desert sites.
A correlation between the number of migrants observed during the night and the number of resting birds in the desert on the following day suggests that an unknown proportion of birds might regularly use an intermittent migratory strategy that includes rest periods by day when crossing the desert, whereas others might adapt a non-stop migratory strategy.