Hot bats: extreme thermal tolerance in a desert heat wave

Climate change is predicted to increase temperature extremes and thus thermal stress on organisms. Animals living in hot deserts are already exposed to high ambient temperatures (T _a) making them especially vulnerable to further warming. However, little is known about the effect of extreme heat events on small desert mammals, especially tree-roosting microbats that are not strongly protected from environmental temperature fluctuations. During a heat wave with record T _as at Sturt National Park, we quantified the thermal physiology and behaviour of a single free-ranging little broad-nosed (Scotorepens greyii, henceforth Scotorepens) and two inland freetail bats (Mormopterus species 3, henceforth Mormopterus) using temperature telemetry over 3 days. On 11 and 13 January, maximum T _a was ～45.0 °C, and all monitored bats were thermoconforming. On 12 January 2013, when T _a exceeded 48.0 °C, Scotorepens abandoned its poorly insulated roost during the daytime, whereas both Mormopterus remained in their better insulated roosts and were mostly thermoconforming. Maximum skin temperatures (T _skin) ranged from 44.0 to 44.3 °C in Scotorepens and from 40.0 to 45.8 °C in Mormopterus, and these are the highest T _skin values reported for any free-ranging bat. Our study provides the first evidence of extensive heat tolerance in free-ranging desert microbats. It shows that these bats can tolerate the most extreme T _skin range known for mammals (3.3 to 45.8 °C) and delay regulation of T _skin by thermoconforming over a wide temperature range and thus decrease the risks of dehydration and consequently death.     

Two pathways ensuring social harmony

Reproductive division of labour is a characteristic trait of social insects. The dominant reproductive individual, often the queen, uses chemical communication and/or behaviour to maintain her social status. Queens of many social insects communicate their fertility status via cuticle-bound substances. As these substances usually possess a low volatility, their range in queen–worker communication is potentially limited. Here, we investigate the range and impact of behavioural and chemical queen signals on workers of the ant Temnothorax longispinosus. We compared the behaviour and ovary development of workers subjected to three different treatments: workers with direct chemical and physical contact to the queen, those solely under the influence of volatile queen substances and those entirely separated from the queen. In addition to short-ranged queen signals preventing ovary development in workers, we discovered a novel secondary pathway influencing worker behaviour. Workers with no physical contact to the queen, but exposed to volatile substances, started to develop their ovaries, but did not change their behaviour compared to workers in direct contact to the queen. In contrast, workers in queen-separated groups showed both increased ovary development and aggressive dominance interactions. We conclude that T. longispinosus queens influence worker ovary development and behaviour via two independent signals, both ensuring social harmony within the colony.     

Torpor at high ambient temperature in a neotropical didelphid,the grey short-tailed opossum (Monodelphis domestica)

The grey short-tailed opossum, Monodelphis domestica, has been an established research animal for more than five decades, but relatively, little is known about its thermophysiology. Here we studied core body temperature (T _b) and metabolic rate (MR) of female adult M. domestica housed in the laboratory at an ambient temperature (T _a) of 26 °C. In expanding previous reports, the average recorded core T _b of M. domestica was 34.3 °C. The T _b of an individual M. domestica can drop below 30 °C (minimal T _b: 28.6 °C) accompanied by a reduction in MR of up to 52 % even while having ad libitum access to food. These findings demonstrate for the first time the presence of spontaneous torpor in M. domestica. Metabolic suppression at relatively high T _a and T _b furthermore broadens our perspective on the use of torpor as a metabolic strategy not just restricted to cold climates.     

Three-year lifecycle,large body,and very high threshold temperature in the cricket <Emphasis Type="Italic">Gryllus argenteus</Emphasis> for special adaptation to desiccation cycle in Malawi

In temperate climates, the initiation and termination of diapause synchronize the stress-tolerant stage with the stressful season and reproduction with the non-stressful season in many insects. Synchronization is often regulated by photoperiodism.Voltinism and the ultimate size of adults are also important determinants for their lifecycle, and different diapause stages and voltinism patterns are known in crickets.Here, we investigated the life history of the African cricket Gryllus argenteus from Malawi, which is a typical arid tropical highland. The climate is characterized by alternating arid and wet seasons, each of which lasts for half a year, and where the available heat mass is much less than lowlands at the same latitude. We first measured the nymphal duration at each rearing temperature and calculated the lower developmental threshold (t ₀) to be 20.19 °C based on Ikemoto and Takai (2000) and 19.38 °C based on a conventional line-fitting method. These values are very high relative to many other insects. The local temperature in winter does not fall below 15 °C, but this is much higher than the lethal limit. This suggested that critical stress in this locality was not coldness but low precipitation in winter. We estimated, based both on local temperature change and the Ikemoto and Takai’s t ₀, that G. argenteus required 3 years to complete its lifecycle unlike wet lowland species, where univoltinism or multi-voltinism are commonplace. Photoperiodism was observed in this species, but due to a lag between annual cycles in photoperiod, temperature, and humidity, photoperiodism alone cannot atune their lifecycle with local conditions.Synchronization in this species was achieved by three different adaptations: photoperiodism, high t ₀, and large body size, which give it a long lifecycle. Although the species cannot achieve a univoltine lifecycle because of its high t₀ value, it can escape from dry season by entering diapause at moderate temperatures, probably thereby achieving adaptive synchrony of lifecycle with both favorable and unfavorable seasons. A comparison between a conventional photothermogram and a newly formulated photohydrogram or photohygrogram demonstrates that even though sufficient heat is available, scarcity of water and thus scarcity of foliage should force the cricket to maintain diapause at intermediate temperature. The results suggested that high t ₀, large body size, and multi-ennial lifecycle mutually affect each other and formulate a unique adaptation under such an extreme environment.     

Laboratory studies of some halogenated ethanes and ethers: Measurements of rates of reaction with OH and of infrared absorption cross-sections

We have measured, using a conventional discharge-flow resonance-fluorescence technique, the rates of reaction between the hydroxyl radical and a series of halogenated ethanes and ethers for the temperature range 230–423 K. Our measurements gave the following Arrhenius expressions (units are cm³ molecule⁻¹ s⁻¹): CF₂HCH₃ (HFC-152), 14.2 × 10⁻¹³ exp-(1050/T); CF₂ClCH₃ (HCFC-142b), 2.6 × 10⁻¹³ exp-(1230/T); CFCl₂CH₃ (HCFC-141b), 5.8 × 10⁻¹³ exp-(1100/T); CF₃CFH₂ (HFC-134a), 5.8 × 10⁻¹³ exp-(1350/T); CF₃CF₂H (HFC-125), 2.8 × 10⁻¹³ exp-(1350/T); CF₃CCl₂H (HCFC-123), 11.8 × 10⁻¹³ exp-(900/T); CF₂HOCF₂CFClH, (enflurane), 6.1 × 10⁻¹³ exp-(1080/T); CFH₂OCH(CF₃)₂, (sevoflurane), 15.3 × 10⁻¹³ exp-(900/T). In two cases, we measured rate constants only at room temperature: CF₃CClBrH (halothane), 6 × 10⁻¹⁴ and CF₂HOCClHCF₃ (isoflurane), 2.1 × 10⁻¹⁴.We also report the following values for the integrated absorption cross-sections of the compounds in the spectral region 800–1200 cm⁻¹ in units of cm⁻² atm⁻¹: CF₂HCH₃, 1155; CF₂ClCH₃, 1422; CFCl₂CH₃, 1995; CF₃CFH₂, 2686; CF₃CF₂H, 1970, CF₃CCl₂H, 1411; CF₃CClBrH, 1400; CF₂HOCF₂CFClH, 4800; CF₂HOCClHCF₃, 3900; CFH₂OCH(CF₃)₂, 2550. We use our measurements to calculate ozone depletion potentials and greenhouse warming potentials relative to CFCl₃ for each compound.     

Hot-blooded singers: endothermy facilitates crepuscular signaling in African platypleurine cicadas (Hemiptera: Cicadidae:<Emphasis Type="Italic"> Platypleura</Emphasis> spp.)

The cicada genus Platypleura has a wide distribution across Africa and southern Asia. We describe endothermic thermoregulation in four South African species that show crepuscular signaling behavior. This is the first evidence of thermoregulation in platypleurine cicadas. Field measurements of body temperature ( T _b) show that these animals regulate T _b through endogenous heat production. Maximum T _b measured was 22.1°C above ambient temperature during calling activity at dusk. The mean T _b during dusk activity did not differ from the mean T _b during diurnal activity. A unique behavior for cicadas, a temperature-dependent telescoping pulsation of the abdomen, was observed in the laboratory during endogenous warm-up. This behavior is part of a unique method of heat generation in endothermic cicadas. Males generally call from trunks and branches within the canopy and appear to use endothermy even when the sun is available to elevate T _b. Endothermy may provide the cicadas with the advantage of decreasing predation and acoustic competition by permitting calling from perches that most complement their cryptic coloration patterns and that ectotherms cannot use due to thermal constraints. In addition, endothermy may permit calling activity during crepuscular hours when atmospheric conditions are optimal for acoustic communication and predation risks are minimal.     

Torpor in the Patagonian opossum (Lestodelphys halli): implications for the evolution of daily torpor and hibernation

Hibernation and daily torpor are two distinct forms of torpor, and although they are related, it is not known how and in which sequence they evolved. As the pattern of torpor expressed by the oldest marsupial order the opossums (Didelphimorphia) may provide insights into the evolution of torpor, we aimed to provide the first quantitative data on the thermal biology and torpor expression of the rare Patagonian opossum (Lestodelphys halli). It is the opossum with the southernmost distribution, has a propensity of autumnal fattening, and therefore, is likely to hibernate. We captured two male Lestodelphys, which while in captivity displayed strong daily fluctuations of body temperatures (T_b) measured with implanted miniature data loggers even when they remained normothermic. In autumn and early winter, torpor was expressed occasionally when food was available, but cold exposure and food withdrawal increased torpor use. The mean T_b throughout the study was 32.2?±?1.4 °C, the minimum T_b measured in torpid Lestodelphys was 7.7 °C, average torpor bout duration was 10.3 h, and the maximum torpor bout duration was 42.5 h. Thus, the pattern of torpor expressed by Lestodelphys was intermediate between that of daily heterotherms and hibernators suggesting that it may represent an ancestral opportunistic torpor pattern from which the derived patterns of daily torpor and seasonal hibernation diverged.     

亚高山草甸土壤呼吸的空间异质性研究

运用传统和地统计学的方法,对山西云顶山亚高山草甸的土壤呼吸、土壤温度、土壤水分和土壤有机碳的空间异质性以及它们的关系进行了分析.传统统计分析表明,土壤呼吸及环境因子均呈正态分布,变异系数在12%~24%之间,属于中等变异;土壤呼吸和土壤有机碳的相关系数(r=0.61)大于和温度(r=0.27)、水分(r=0.26)的相关系数,表明土壤有机碳对土壤呼吸空间分布的影响要远大于土壤温度和水分的影响.地统计学分析结果表明,线性模型能很好地反映土壤呼吸以及环境因子的空间结构特征.土壤呼吸、土壤温度、土壤水分及土壤有机碳的C0/(C0+C)值分别为41%、3%、77%、57%,表明土壤温度具有高度的空间自相关性,土壤呼吸和土壤有机碳具有中等程度的空间自相关性,土壤水分表现出较弱的空间自相关性,结构因素对土壤温度和土壤呼吸的空间分布起着主导作用,而随机因素对土壤水分和土壤有机碳的空间变异则起着主导作用;土壤呼吸、温度和水分的变程均为53.2 m,有机碳的变程为52.1 m;土壤呼吸和土壤温度具有较好的分形特征,存在尺度上的依赖性.分维数从大到小依次为:土壤水分(1.96)>土壤有机碳(1.95)>土壤呼吸(1.85)>土壤温度(1.60),表明土壤水分依赖于尺度的变异最小,空间分布结构最复杂,而土壤温度的空间分布格局最简单;土壤呼吸的空间分布表现出与土壤水分和有机碳相似的特点,并表现出自己的规律性.随着置信水平和估计精度的降低,土壤呼吸及其影响因子所要求的采样数量均出现较大幅度的下降.     

Torpor and activity in a free-ranging tropical bat: implications for the distribution and conservation of mammals?

Bats are most diverse in the tropics, but there are no quantitative data on torpor use for energy conservation by any tropical bat in the wild. We examined the thermal biology, activity patterns and torpor use of two tree-roosting long-eared bats (Nyctophilus geoffroyi, 7.8?g) in tropical northern Australia in winter using temperature telemetry. Bats commenced activity about 20?min after sunset, ended activity about 2.5?h before sunrise and entered torpor everyday in the early morning even when minimum ambient temperatures (T _a) were as high as 23°C. On average, bats remained torpid for almost 5?h, mean minimum skin temperature (T _skin) measured was 22.8?±?0.1°C and daily T _skin minima were correlated with T _a. Our study shows that even in the tropics, torpor is frequently employed by bats, suggesting that worldwide most bat species are heterothermic and use torpor for energy conservation. We propose that the ability of employing torpor and the resulting highly plastic energy requirements may partially explain why these small insectivorous bats can inhabit almost the entire Australian continent despite vastly different climatic and likely trophic conditions. Reduced energy requirements also may permit survival in degraded or modified habitats, reduce the need for foraging and reduce exposure to predators. Thus, the ability to employ torpor may be one important reason for why most Australian bats and other heterothermic mammals have not gone extinct whereas many obligatory homeothermic mammals that cannot employ torpor and have high energy and foraging requirements have suffered high rates of extinctions.     

The characterization and comparison of ozone exposure indices used in assessing the response of loblolly pine to ozone

Using the 1988 and 1989 experimental results obtained for two loblolly pine half-sibling families (GAKR 15–23 and GAKR 15–91) at the Auburn University intensive field research site, we: (1) explored the performance of a set of exposure indices; (2) characterized the ambient air and charcoal-filtered air treatments at Auburn and compared the values of the O₃ exposure indices with those values calculated for ambient O₃ monitors for a select set of sites; (3) identified and characterized O₃ treatments in the Auburn open-top exposure chambers where an adverse effect was noted; and (4) identified where such experimental exposure regimes occurred under ambient conditions. We found that the SUMO exposure index did not perform adequately. We were unable to distinguish among the performances of the SUM06, W126, and SUM08 exposure indices. The results of the analyses of six estimated logistic parameters for a model of diameter² × height (d²h) vs time indicated O₃ effects for both families. At pH 4.3 (near ambient conditions), a response to O₃ was detected in the NF × 2.5 treatments for both families for t₂, the approximate time of maximum growth during the second year. Using ln (final d²h), family 23 did not show O₃ effects. A comparison of the exposures experienced in the NF × 2.5 treatments with those occurring under ambient conditions at other locations showed that in 1983 and 1986, the San Bernardino County (CA) site experienced O₃ exposures similar to those values experienced at the NF × 2.5 treatments in 1989.     

Analysis of temperature effects on seasonal and interannual variation in CH4 emission from rice-planted pots

Rice (Oryza sativa L.) paddies are one of the major sources of atmospheric methane (CH₄), a greenhouse gas. To elucidate the quantitative relationship between CH₄ emission from rice paddies and temperature, 6 years data of CH₄ emission from pot experiments were analyzed in terms of the sum of effective temperature (∑(T−15); T is the daily mean air temperature (°C)). The base temperature of 15 °C was adopted as the 0 °C physiological temperature for methanogens. Significant positive correlations between total CH₄ emission throughout the rice growth period and ∑(T−15) were observed for pots with rice straw (RS) application at a rate of 6 g kg⁻¹ soil, which corresponds to 6 t ha⁻¹ (r=0.830⁷¹), and those without RS application (r=0.818⁷¹). It was confirmed that temperature is a major factor affecting the interannual variation in CH₄ emission. For the 1993 and 1995 data sets that include seven and four levels of RS application, the relationship between seasonal CH₄ emission and RS application rate could be expressed using linear functions (r=0.988⁷¹, 0.996⁷¹), the slopes of which were similar to each other. Based on these findings, we confirmed that the dependence of seasonal CH₄ emission on both temperature and RS application rate can be described by a single linear equation.     

山西高原落叶松人工林土壤呼吸的空间异质性

基于对华北落叶松(Larix principis-rupprechtii)人工林样地3个取样尺度(4、2、1 m)土壤呼吸(Rs)及其影响因子的观测,运用传统和地统计学的方法分析了Rs的空间变异性及其与影响因子之间的内在联系.传统统计分析表明:Rs及其它相关因子的空间变异均属于中等变异;Rs与10 cm、15 cm深度的土壤温度(T10、T15)和全氮(N)呈极显著正相关(P0.01),与凋落物含水量(Lm)呈显著正相关(P0.05),与碳/氮比(C/N)呈显著负相关(P0.01),与5 cm深度的土壤温度(T5)、土壤水分(Ws)、凋落物量(Lw)和全碳(C)相关性不显著(P0.05);多元逐步回归分析表明:Lm、T10、N和Ws这4个因子能解释土壤呼吸空间变化的36%.地统计学分析表明:Rs具有中等程度的空间自相关性,随机部分引起的空间异质性占39.5%,结构因素占60.5%,气候、地形、土壤等结构因素起着主导作用;不同土壤指标的变程不相同,Rs和T10的变程差异不大,在25 m左右;土壤各指标的分维数大小依次为:Lw(1.95)=C/N比(1.95)N(1.91)C(1.89)Rs(1.78)Lm(1.77)Ws(1.69)T10(1.42).Rs的空间分布模式与T10、Lm、C和N的空间分布模式较为一致,而与Ws、C/N比的空间分布模式不同;在同一置信水平和估计精度下,不同土壤指标的必要采样数量不相同,取决于该指标的空间变异程度.     

Effects of temperature,TSP and per cent non-exchangeable material in determining the gas-particle partitioning of organic compounds

The temperature dependence of the measured, gas-particle partitioning ratio (F_T/TSP)/A_T has been examined for the case when a constant fraction x (%) of a compound is assumed to be bound within the particulate matter, and non-exchangeable with the gas phase. The parameter F_T is the total (exchangeable + non-exchangeable) measured concentration in the atmosphere (ng m⁻³), A_T is the gaseous concentration (ng m⁻³), and TSP is the level of suspended atmospheric particulate matter (μg m⁻³). It is assumed that the true thermodynamic constant K_p depends upon 1/T according to log K_p = m_p/T + b_p where m_p depends on the enthalpy of desorption of the compound of interest, b_p depends in part on other properties of the compound as well as the specific surface area of the particulate matter, and T is the temperature (Kelvin). When K_p or TSP are low, the difference between the measured quantity (F_T/TSP)/A_T and K_p can be significant even when the non-exchangeable fraction x is as low as a few per cent. This approach has been used to examine the PAH data set of Yamasaki et al. [(1982) Env. Sci. Technol.16, 189–194]. It was found that the Yamasaki data set does not allow estimates of x that are consistent with the current understanding of the temperature dependence of log K_p values. A likely reason for this result is some dependence of m_p and b_p on the exact nature of the particulate matter and atmospheric conditions such as relative humidity. It is concluded that estimates of x values for a given compound on actual particulate matter may only be possible by the direct examination of individual particulate matter samples.     

福建西部山地水土流失区土壤呼吸的空间异质性

土壤呼吸(Rs)作用的空间异质性对于准确估算水土流失区碳收支具有重要意义.通过对长汀县河田镇59个样地的土壤呼吸及土壤全氮(TN)、碳氮比(C/N)、有机碳含量(SOC)、叶面积指数(LAI)、土壤温度(T_(10))、土壤湿度(W)等影响因子测定的基础上,运用传统和地统计学的方法分析了土壤呼吸及其影响因子的空间异质性.结果表明,Rs及其影响因子的变异程度大小依次为:LAISOCTNRsC/NT_(10)W;Rs与T_(10)呈极显著正相关(P0.01),与TN呈显著正相关(P0.05),与其他因子的相关性不显著(P0.05);TN、SOC和T_(10)这3个因子可以解释土壤呼吸27%的空间变化.地统计学分析结果表明:Rs具有中等程度的空间自相关性,结构性因子引起的空间异质性占52.89%,与随机因素的占比(47.11%)相当;Rs及其影响因子的分维数大小依次为:RsLAIC/NT_(10)SOCWTN;Rs的空间分布格局与TN和T_(10)的空间分布格局较为一致,而与C/N、SOC、LAI的空间分布格局不同.在95%置信水平和90%估计精度下,Rs的合理采样数量为62个.     

水培海马齿对海水菲污染修复作用的初步研究

采用水培法研究了海洋滩涂耐盐植物海马齿(Sesuvium portu lacastrum Linn.)对海水菲污染的修复作用.结果显示,实验4d后,不种植海马齿的对照组、种植海马齿的抑菌组和不抑菌组海水中菲浓度分别从0.988、0.942和0.957mg·L-1降至0.553、0.185和0.070mg·L-1,降低了44.0%、80.4%和92.7%;与对照组相比,抑菌组(T1)和不抑菌组(T2)海水中菲的去除率分别提高了36.4%和48.7%,不抑菌组又比抑菌组高12.3%.利用差减法计算的结果显示,在与自然水体接近的不抑菌条件下,菲的非生物损失、海马齿的作用和微生物的作用,三者对海水中菲浓度降低(92.7%)的贡献分别为44.0%、36.4%和12.3%,海马齿植株内菲的积累量则仅占海水中菲减少量的2.6%.研究表明,水培海马齿可明显提高菲污染海水中菲的去除率,其中,植物与微生物共同发挥着重要的作用,但植物积累不是海马齿修复海水菲污染的主要机制.     

Heterogeneous transformation of peroxyacetylnitrate

The heterogeneous decomposition of peroxyacetylnitrate (PAN) has been investigated using a flow reactor and infrared spectroscopic analysis. The decomposition rate in air due to glass surfaces follows the relation d[PAN]/dt = −S/V([PAN] × 7 × 10⁷ + [CH₃C(O)OO] × 5 × 90¹²)exp(−9382/T) molecules cm⁻³ s⁻¹ (S/V=surface to volume ratio). The rate observed for NH₄HSO₄-covered surfaces is lower than in the glass case. The rate is high enough to affect many laboratory experiments but too slow to have any influence on PAN decomposition under ambient conditions.     

Preparation of MnO2 decorated Co3Fe1Ox powder/monolithic catalyst with improved catalytic activity for toluene oxidation

In this paper, KMnO₄ was used to pre-treat Co₃Fe-layered double hydroxides (LDH) precursor to prepare MnO₂ decorated Co₃Fe₁O_x catalyst. The toluene oxidation performance of the catalyst was investigated systematically. The optimized 0.1MnCF-LDO catalyst exhibited the best catalytic performance, and the temperatures of 50% and 90% toluene conversion (T₅₀ and T₉₀) were 218 and 243°C, respectively. The apparent activation energy (E_a) was 31.6 kJ/mol. The characterization results showed that the pre-redox reaction by KMnO₄ could increase the specific surface area, Co³⁺ species amount and oxygen defect concentration of the catalyst, which are the main reason of the improved toluene catalytic activity. Besides, this method was also applied to enhance toluene oxidation of iron mesh based monolithic catalyst. The 0.1MnCF-LDO/Iron mesh (IM) catalyst showed a 90% toluene conversion at around 316°C which was much lower than that of without MnO₂ addition (359°C). In addition, the water resistant of all the catalysts was studied as well, all the samples showed relatively good water resistance. The toluene conversion still remained to be over >80% even in the presence of 10 vol.% water vapor.     

地表臭氧浓度升高对旱作农田N2O排放的影响

通过田间试验,在冬小麦和大豆生长季设置3种不同臭氧(O3)浓度的处理,包括自由空气(对照,CK)、100 n L·L-1O3浓度(T1)和150 n L·L-1O3浓度(T2),采用静态箱-气相色谱法测定N2O排放通量,研究地表O3浓度升高对冬小麦-大豆轮作系统N2O排放的影响.结果表明,与CK相比,在冬小麦返青期,T1和T2处理都降低了土壤-冬小麦系统N2O累积排放量,降幅分别为37.8%(P=0.000)和8.8%(P=0.903);在拔节-孕穗期,T1和T2处理使N2O累积排放量分别降低了15.0%(P=0.217)和39.1%(P=0.000);从冬小麦全生育期来看,T1、T2的N2O累积排放量分别降低了18.9%(P=0.138)和25.6%(P=0.000).由于本年度大豆生长季降水偏少,受干旱胁迫的影响,O3浓度升高对大豆田N2O排放的作用不明显.本研究表明地表O3浓度升高会减少旱作农田N2O排放量.     

Astaxanthin and papilioerythrinone in the skin of birds: a chromatic convergence of two metabolic routes with different precursors?

Carotenoids are organic pigments involved in several important physiological functions and may serve as indicators of individual quality in animals. These pigments are only obtained by animals from the diet, but they can be later transformed into other carotenoids by specific enzymatic reactions. The diet of farm-reared and probably wild red-legged partridges (Alectoris rufa) is mainly based on cereals that contain high levels of lutein and zeaxanthin. These two carotenoids are also predominant in internal tissues and blood of red-legged partridges. However, in their integuments, astaxanthin and papilioerythrinone (the last one identified in this work) are mainly present in their free form and esterified with fatty acids. According to available literature about carotenoid metabolism in animals, we propose that astaxanthin (λ _max?=?478 nm) and papilioerythrinone (λ _max?=?452–478 nm) are the result of a chromatic convergence of the transformation of dietary zeaxanthin and lutein, respectively. Moreover, the results obtained in this work provide the first identification by liquid chromatography coupled to accurate mass quadrupole time-of-flight mass spectrometer system of papilioerythrinone (m/z 581.3989 [M?+?H]⁺) in the skin (i.e., not feathers) of a vertebrate. Astaxanthin and papilioerythrinone are very close in terms of chemical structure and coloration, and the combination of these two keto-carotenoids is responsible for the red color of the ornaments in red-legged partridges.     

一体化氧化沟固液分离和回流机理探讨

论述了一体化氧化沟中固液分离和污泥回流的基本原理，提出了固液分离器的表面负荷ＳＯＲ与污泥层厚度、回流污泥浓度等有关，计算模型为ＳＯＲ＝１１＋Ｒ·ＨｗＴ·ＣｕＣ０．固液分离器与二沉池的功效显著不同，所需面积远低于二沉池，在固液分离器内不发生污泥压缩、回流及时，不易受污泥沉降性能影响，是值得推荐的一体化氧化沟固液分离方式．