Artificial light at night: implications for early life stages development in four temperate freshwater fish species

Flora and fauna have both evolved under a natural cycle of light and dark. But especially in urban areas, the night is now increasingly disturbed by artificial light. Many traits and behaviours in fish are triggered by a circadian clock, for example hatching and swim bladder inflation, which predominantly take place at dusk or night. As lighting becomes brighter and extends farther into rural areas, the distinction between day and night becomes increasingly blurred. Therefore, the loss of diurnal trigger by artificial light at night was hypothesized having deleterious effects on these traits and impact fish reproduction. To assess these effects, eggs of four native freshwater fishes, Eurasian perch Perca fluviatilis, roach Rutilus rutilus, bleak Alburnus alburnus and chub Leuciscus cephalus, were incubated under two different light conditions: a photoperiod of 14 h light:10 h darkness (LD) and continuous illumination (LL). The time to hatch and swim bladder inflation was recorded. The species showed inconsistent reactions to the light treatments. In roach and bleak, the time to 50% hatch was longer in LL, whereas continuous lighting had an accelerating effect in chub. Incubation in LL elongated the hatching period in perch and roach and, in perch, the onset of darkness seemed to trigger hatching. The swim bladder inflation was significantly promoted by continuous light in chub and bleak but was not affected in roach. In conclusion, nocturnal artificial illumination could have an effect on hatching and initial swim bladder filling by masking the day–night-change and thereby diminish the trigger effect. However, the reactions were species specific and the increase in variation indicated a lack of diurnal triggering, whilst a general deleterious effect of artificial light at night has not been identified on early life stages.     

A cyclicity in the early brigantian (D2) limestones east of the clwydian range,north wales and its use in correlation

For the first time, minor cyclicity is described from some limestones in the lower part of the Brigantian (D2) succession of the Mold district North Wales which can be traced throughout the area enabling a detailed correlation to be established. The minor cyclicity may have been caused by eustatic sea-level fluctuations. Periods of emergence associated with each regressive phase are demonstrated by the presence of subaerial features and terrestrial deposits. The lateral persistence of the cycles is confirmed by comparison with established faunal and lithological horizons. Correlation with other cyclic Brigantian strata in Yorkshire, Derbyshire and Bristol is briefly discussed. The Asbian/Brigantian (D1/D2) boundary in North Wales is described and distinctive faunal and lithological changes similar to those in the area of the stratotype in north England have been recorded.     

Total N,total P and organic matters content in floodplain soils of Xianghai Nature Reserve

Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.     

Deformability properties of model granular soils under true triaxial compression conditions

The study presents a review of modifications to the design of true triaxial test apparatuses and described a new mixed boundary apparatus to study the stress-strain behavior of coarse-grained soil under true triaxial compression conditions. It was shown that the deviatoric component plays an important role in affecting the volumetric compression of coarse-grained soil. The study analyzed the influence of different stress-strain characteristics on the development of lateral earth pressure.     

Archaeal Communities of Frozen Quaternary Sediments of Marine Origin on the Coast of Western Spitsbergen

Izvestiya, Atmospheric and Oceanic Physics - The archaeal composition of permafrost samples taken during the drilling of frozen marine sediments in the area of the Barentsburg coal mine on the east...     

Application of analytical hierarchy process (AHP) for flood risk assessment: a case study in Malda district of West Bengal,India

A field experiment was conducted from 2 May 2010 to 1 May 2012 in the Gurbantunggut Desert, the second largest desert in China, to investigate saltation activity and its threshold velocity, and their relations with atmospheric and soil conditions. The results showed that saltation activity occurred more frequently during 08:00–20:00 Local Standard Time in spring and summer, with air temperatures between 20.0 and 29.0 °C, water vapor pressures between 0.6 and 0.9 kPa, soil temperatures between 25.0 and 30.0 °C, and a soil moisture lower than 0.04 m³/m³. At 2 m height, the saltation threshold velocity varied between 11.1 and 13.9 m/s, with a mean of 12.5 m/s. Threshold velocity showed clear seasonal variations in the following sequence: spring (11.7 m/s) < autumn (12.7 m/s) < summer (13.6 m/s). Affected by soil conditions, aeolian sand transport was weak, with an average annual aeolian sand that transported across a section (1.0 m × 2.0 m) of less than 6.0 kg.