Lesions confined to the ventromedial hypothalamus decrease the frequency of coital contacts in female rats

Ovariectomized female rats received either bilateral radiofrequency lesions of the ventromedial nucleus of the hypothalamus (VMH) or control treatments and were tested for copulatory activity following either estrogen (E) alone, or E plus progesterone (P) administration. In separate experiments the females were tested in two testing apparatuses both of which allowed the test females to control their contacts with sexually active males. One of the testing apparatuses also allowed the females to control their contacts with sexually inactive males and ovariectomized females. Females receiving VMH lesions engaged in fewer coital contacts with sexually active males than sham-operated females in the E plus P condition. Lesioned females also tended to spend less time with sexually active males than did sham operates in both the E and E plus P hormonal conditions. The VMH-lesioned females did not differ from the sham-operated females in the ability to display lordosis during the coital contacts or the frequency and duration of visits to the inactive males or ovariectomized females. The sham-operated females did have some transitory alterations in copulatory behavior in comparison to unoperated control females.     

High‐Performance Thickness Insensitive Perovskite Solar Cells with Enhanced Moisture Stability

High‐performance perovskite solar cells (PVSCs) with absorber layer thickness insensitive features are important for practical fabrication, however these features are difficult to be realized. There are very few reports of the fabrication of polycrystalline PVSCs with power conversion efficienies (PCE) insensitive to film thickness beyond 600 nm. The main reason lies in more serious recombination of the thick perovskite layer compared to the thin layer. Herein, this challenge is addressed by a simple hot casting method to formulate high‐quality perovskite film with enlarged grain size, high carrier mobility, and reduced defects. It is found that increasing the temperature to 70 °C can dramatically increase the film thickness and enlarge the perovskite crystal, therefore boost the efficiency from ≈16% to ≈19%. Notably, a record PCE of 19.54% is achieved with 850 nm thick perovskite film, which is among the highest efficiency for thick‐film PVSCs. The PCE remains steady around 19% when modifying the perovskite layer from 700 to 1150 nm. Moreover, these thick‐film PVSCs show good stability with 80% of its initial efficiency after 30 d in air with a humidity of 50%. Overall, this simple yet effective method has a great potential in the mass manufacture of PVSCs.     

Genes involved in copper resistance influence survival of Pseudomonas aeruginosa on copper surfaces

Aims:  To evaluate the killing of Pseudomonas aeruginosa PAO1 on copper cast alloys and the influence of genes on survival on copper containing medium and surfaces.
Methods and Results:  Different strains of P. aeruginosa were inoculated on copper containing medium or different copper cast alloys and the survival rate determined. The survival rates were compared with rates on copper-free medium and stainless steel as control. In addition, the effect of temperature on survival was examined.
Conclusions:  Copper cast alloys had been previously shown to be bactericidal to various bacteria, but the mechanism of copper-mediated killing is still not known. In this report, we demonstrate that P. aeruginosa PAO1 is rapidly killed on different copper cast alloys and that genes involved in conferring copper resistance in copper-containing medium also influenced survival on copper cast alloys. We also show that the rate of killing is influenced by temperature.
Significance and Impact of the Study:  To use copper surfaces more widely as bactericidal agents in various settings, it is important to understand how genes influence survival on these surfaces. Here we show that genes shown to be involved in copper resistance in P. aeruginosa PAO1 can have an impact on the length of survival time on copper cast alloys under certain conditions. This is an important first step for evaluation of future use of copper surfaces as bactericidal agents.     

安徽长江滩地杨树人工林生物量和养分积累

安徽长江外滩Ⅰ-69杨树无性系人工林11年林分生物量达到90.2t·hm^-2,平均生产量为8.2t·hm^-2·a^-1,平均单株生产量为21.9kg·a^-1,与相同纬度带一般立地条件林分相比单株生产量高0.7%;另外林分叶面积指数为3.32m²·m^-2,造林后第3年叶面积指数的净增值达到最高,同时林分生产力开始进入最高水平该林分每生产1t干物质需要N 3.369kg、P 0.327kg、K 2.424kg、Ca 7.465kg、Mg 0.2kg、Cu 0.0073kg、Mn0.01868kg、Fe 0.1115kg和Zn 0.00268kg,同时吸收S 0.72kg、Cr 0.000252kg、Cd 0.0O039kg和Pb0.00043kg.年轮中元素含量逐年有波动,N和K呈负相关,而N与P则表现为正相关;滩地的淹水时间对年轮中P含量影响较大,其次是N,与K含量呈负相关,但不显著.     

Endogenous activity rhythm in Talitrus saltator,Britorchestia brito (Crustacea,Amphipoda) and Tylos europaeus (Crustacea,Isopoda) from Barkoukech Beach (Tabarka,Tunisia)

The locomotor activity rhythm of three supralittoral crustacean species, Tylos europaeus (terrestrial isopod) and Britorchestia brito and Talitrus saltator (amphipod, Talitridea), was investigated in Barkoukech Beach. The rhythm was monitored in individual animals in spring under continuous darkness and constant temperature. Results revealed that whatever the species, actograms and mean activity curves showed that specimens of T. europaeus and T. saltator concentrated their activity during the subjective night; whereas, B. brito concentrated its activity during the subjective day. The three species exhibited a circadian locomotor rhythm with mean circadian period, respectively, equal to 24h41′ ± 0h44′, 24h46′ ± 0h55′ and 25h21′ ± 1h16′. The most stable locomotor rhythm was found in T. saltator (0.444 ± 0.246). Furthermore, individuals of T. europaeus were significantly more active (10h47′ ± 2h52′) than the two amphipods. Differences in the activity patterns of the three species will be discussed as an adaptative strategy to respond to interspecific competitive interactions.     

Talitrid orientation as bioindicator of shoreline stability: Protected headland-bays versus exposed extended beaches

The behaviour of talitrids, being a local adaptation to beaches, is known to be related to environmental stability. The use of behavioural responses of resident populations as bioindicator of shoreline stability has been tested under various conditions, including after soft and hard engineering actions to stabilise eroded beaches. Port structures likely have impact on sediment longshore transportation and shoreline stability. The question was whether talitrid orientation behaviour could be proposed as bioindicator of impacts also for sandy bays of limited extension and highly used for recreation, such as those in the vicinity of touristic port structures. Orientation experiments were carried out on a set of sandy beaches of different extension and morphology, each of them in the vicinity of a touristic port, across the Mediterranean coasts. The protocol included field orientation tests of populations of talitrids, then analysed in terms of orientation precision seawards (considering sun compass orientation as the most locally adapted behavioural mechanism) in different seasons (before and after the touristic season) and times of day. The populations from more protected (either naturally or artificially) headland-bays showed a higher precision of orientation with respect to the shoreline direction than those from extended beaches, more subject to changes in longshore sedimentary transport as consequence of natural and human activities. The distance from the port and touristic pressure had no influence on talitrid orientation. An important stabilising factor for the sandy beach ecosystems, including talitrid populations and their behavioural adaptation, appeared to be the presence of seagrass banquette. The behavioural data point out that biotic information proceeding from local animal populations linked to beach sediments may complement sedimentology data and allow scaling the impacts occurring on a developed coastline. This becomes particularly relevant when considering interdisciplinary approaches to monitoring strategies.     

Ichnology of Lower Jurassic beach deposits in the Shemshak Formation at Shahmirzad,southeastern Alborz Mountains,Iran

A 19 m thick package of well-sorted lowermost Jurassic (Hettangian-Lower Sinemurian?) sandstones within the Shemshak Formation of the southeastern Alborz Mountains displays features characteristic of foreshore to upper shoreface environments such as tabular bedding, low-angle lamination, trough cross-stratification, parting lineation, and oscillation ripples. In contrast to most other beach successions recorded in the literature the sandstones contain a trace fossil assemblage characterised by low abundance but comparatively high diversity. The assemblage, comprising 14 ichnotaxa, is dominated by Palaeophycus heberti, Rhizocorallium irregulare, Gyrochorte comosa, and Parahaentzschelinia surlyki. Contrary to predictions, which assume a dominance of suspension-feeders in such high-energy environments, the trace fossil assemblage represents a variety of ethological groups ranging from suspension-feeders to deposit-feeders, detritus-feeders, scavengers, and a possible trap constructor (Ctenopholeus), whereby deposit-feeders predominate. This anomaly is explained by a high amount of organic detritus in the sediment, indicated by abundant plant material, and a position of the beach in the vicinity of a river mouth.     

Sandblasting as a possible factor controlling the distribution of plants on a coastal dune system

Intensity of the abrasive effect of wind-borne sand – sandblasting – in addition to other environmental factors was measured at two vegetation zones on a sandy beach and one site at an inland area. One zone on the beach included foredunes sparsely vegetated by dune species such as Carex kobomugi and Calystegia soldanella. The other zone which was located ∼50 m inland from the first zone was flat grassland dominated by inland species such as Miscanthus sinensis and Imperata cylindrica var. Koenigii. The inland site consisted of short grassland located 3 km inland from the beach. Intensity of sandblasting was estimated by the whiteness of a transparent plastic sheet exposed to the air for 2 weeks. This sheet turned whitely opaque when it was abraded by wind-borne sand. The other environmental factors measured at the beach were intensity of salt spray, soil water content, soil salinity, and sand accumulation, while intensity of salt spray was the only additional factor measured at the inland site. Intensity of sandblasting was considerably higher at the foredune zone, while that at the grassland zone was as low as that at the inland site. Considerable salt spray was detected at the foredune and grassland zones. Differences in other environmental factors were small between the two zones on the beach. In order to compare the difference in tolerance to sandblasting, a jet of sand was applied to one ordinary species, C. kobomugi, from the foredune and two species, M. sinensis and I. cylindrica, from the grassland zone. The difference in tolerance was determined by the decrease in the area of green leaf after applying sandblasting with commercial sandblaster and/or spraying with sea water. M. sinensis and I. cylindrica lost much of the leaf area after sandblasting and salt spraying, while C. kobomugi lost little. These results indicated that one of the characteristic environmental factors of a foredune is the high intensity of sandblasting accompanied by salt spray, and that species found in the foredune are more tolerant to sandblasting than species distributing in more inland areas.     

Nest architecture of the leaf-cutting ant <Emphasis Type="Italic">Acromyrmex rugosus rugosus</Emphasis>

The prominent nests mounds of many ant species are one of the most obvious signs of their presence, yet the subterranean architecture of nests is often poorly known. The present work aimed to establish the external and internal structure of nests of a species of leaf-cutting ant, Acromyrmex rugosus rugosus, by either marking the interior of nests with talcum powder, or forming casts with cement. Twelve nests were excavated and surveyed, with eight being marked with talcum powder and four cast with cement. The external and internal structure of the nests was highly variable. The largest and smallest nests had mound areas of 9.89 m² and 0.01 m² respectively. The number of chambers found ranged from 1 to 26, with maximum dimensions of between 6 and 70 cm. Chambers were found close to the soil surface (6 cm) down to a maximum depth of 3.75 m. In addition to chambers containing fungus garden, some chambers were found to be empty, filled with soil or filled with waste, the first time this has been recorded in a species of Acromyrmex. The nests of A. rugosus rugosus appear to be unusually complex for the genus, containing a diversity of irregular chambers and tunnels. Received 21 December 2006; revised 30 May 2007; accepted 1 June 2007.