Cuticular Hydrocarbons and Soldier Defense Secretions of <Emphasis Type="Italic">Reticulitermes</Emphasis> in Southern California: A Critical Analysis of the Taxonomy of the Genus in North America

Cuticular hydrocarbons (CHC) and soldier defense secretions (SDS) were characterized for collections of Reticulitermes from six counties (Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Santa Barbara) in southern California. Collection sites included the type locality for R. hesperus, Lake Arrowhead (formerly known as Little Bear Lake) in the San Bernardino Mountains. In southern California, there are two CHC phenotypes, SC-A and SC-B, which are easily distinguished by the presence or absence of 5-methyl pentacosane, 5-methyl heptacosane, 5,17-dimethyl pentacosane, and 5,17-dimethyl heptacosane. These phenotypes are similar, but not identical, to previously designated phenotypes of Reticulitermes from northern California. The SDS of termites collected from southern California were characterized; (—)-germacrene A was abundant in all but the four samples from Lake Arrowhead. Soldiers of phenotype SC-A produced >79% germacrene A. The four samples from Lake Arrowhead produced no germacrene A, but contained >78% γ-cadinene. The SDS from the Lake Arrowhead samples were more similar to those of CA-A/CA-A′ from northern California than to any of the CHC phenotypes from southern California. Soldiers of CHC phenotype SC-B produced germacrene A, with the proportion varying from 16.2 to 98.7%. The SDS of SC-B were more similar to those of SC-A than to any of the phenotypes from northern California. The CHC phenotype SC-A found in southern California likely represents R. hesperus and SC-B appears to be a new, as yet undescribed species. We discuss the state of current taxonomic research on Reticulitermes.

地层储能技术在大温差水源热泵中的应用

地层储能技术以低焓地热能作为冷热源,在为室内制冷或供暖的同时,通过系统循环将能量存于储能井中,达到夏热冬用,冬冷夏用的目的。大温差水源热泵技术通过提高供/回水的温差提高水源热泵机组的能效比。将这两种技术联合使用则可以更有效地发挥两者的长处,达到节省、高效利用水资源的目的。以某单位干休所水源热泵工程为例,介绍了此两项技术在工程中的应用。     

Subterranean-SAE算法的条件立方攻击

美国国家标准与技术研究院(NIST)于2018年开始征集轻量级认证加密和哈希算法标准,其中Subterranean 2.0密码套件是晋级到第二轮的32个候选算法之一. Subterranean-SAE是Subterranean2.0密码套件中的一种认证加密工作模式. 2019年,刘富康等人对4轮空白轮(4 blank rounds)的Subterranean-SAE算法进行了基于条件立方的密钥恢复攻击,此攻击有效的前提假设是:当条件变量满足条件时输出代数次数为64,否则为65.但刘富康等人并没有验证该假设是否成立.借助三子集可分性理论,本文首次提出了在初始状态未知场景下评估输出代数次数的新技术,并将该技术成功应用于4轮空白轮Subterranean-SAE算法.实验结果表明, 4轮空白轮Subterranean-SAE算法32个输出比特的代数次数上界为63,因此刘富康等人的密钥恢复攻击实际为区分攻击.进一步,本文提出降低立方维数、扩展立方变量选取范围的策略,并成功改进了Subterranean-SAE算法条件立方的搜索方法.利用此方法我们共搜索到24组33维立方并以此构造条件立方攻击,...     

The effects of subterranean clover phytoestrogens on sheep growth, reproduction and carcass characteristics

The aim of the present study was to evaluate the effect of a prolonged administration of phytoestrogens on sheep growth rate, female reproductive response, lamb carcass conformation and meat quality. To investigate these effects, two groups of Comisana sheep (24 females and 20 males, initial average live weights of 25.0 and 29.9 kg, respectively) were fed on subterranean clover (SC, phytoestrogen content = 0.8 mg/g of DM) and Italian ryegrass (C, non-oestrogenic control diet) for about one year. Feedstuffs were offered ad libitum and supplemented with maize grain and sunflower meal to maintain an adequate and similar energy and protein intake. The results demonstrated that the prolonged administration of the selected subterranean clover cultivars, with low formononetin content (lower than 10% of total isoflavones on dry basis), did not affect ewe reproduction but induced a significant improvement in animal weigh gain and, in males, good carcass and meat characteristics.     

Towards an Architectural History of Performance: Auxiliarity,Performance and Provision in Historical Persian Architectures

Despite its extensive empire, Persia historically presented a challenging environment for the building of structures and infrastructure. The mountainous landscape of the Iranian plateaus has an arid or semi-arid climate with distinct seasonal variations and temperatures that fluctuated throughout the day. Despite this, water management and soil-fertilisation strategies and passive environmental modulation in architecture were all highly developed previous to the 19th century so as to be finely attuned to the local context, while also responding to the greater demands of a centralised empire. Here Michael Hensel, Defne Sunguroğlu Hensel, Mehran Gharleghi and Salmaan Craig discuss and illustrate their detailed findings of the performance of historic structures. These include qanats (water canals), water cisterns, ice houses and pigeon houses as well as the seminal Khaju Bridge in Isfahan and the Boroujerdi's House in Kashan.     

Evidence for trail-pheromone precursor in termiteReticulitermes speratus (Kolbe) (Rhinotermitidae: Isoptera)

Whole body extracts of the termite,Reticulitermes speratus, were subjected to various chemical operations and bioassays to examine the presence of trail-pheromone precursor. Fractions that mainly contained fatty acid esters were obtained from hexane extracts by means of silica gel column chromatography. Trail-following activity of the fractions was activated by alkaline hydrolysis, while the original fractions did not show any conspicuous activity. Bioassay showed that the activity of hydrolyzed product was approximately 20 times as high as the original hexane extract. This suggests that the precursor candidate could be stored in termite bodies as an esterified form. Chemical analyses revealed that the complete structure of the hydrolyzed product was coincident with that of the native pheromone ((Z,Z,E)-3,6,8-dodecatrien-1-ol).     

Subterranean space use in Cappadocia: The Uchisar example

Globalization enabled people to learn about the world in which they live in than ever before in the past. Today’s global culture is determined by a rapidly growing communication network and advancing technologies. As a consequence, sustainability of local natural environments and cultural heritages becomes a global issue, while local sites become learning grounds for global communities. As one of the best example of man’s symbiotic relationship with nature Cappadocia, located in Central Anatolia, offers many possibilities and lessons for underground habitation. This paper aims to discuss the ancient settlement of Uchisar in Cappadocia unique for its creative subterranean space use. The focal points of discussion are physical geography, dominating residential patterns of underground space use and potentials for integrating innovative techniques of documentation and fortification for the sustainability of the existing residential tissue.     

Identification of trail pheromone precursors from Subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)

Whole-body extracts of the termite,Coptotermes formosanus Shiraki served for examining the presence of trail pheromone precursor(s). Three trail pheromone precursor candidates, identified as dodecatrienyl stearate, dodecatrienyl oleate, and dodecatrienyl linoleate, were isolated using various chromatographic methods in conjunction with bioassay and by capillary GC-MS analyses.     

Cuticular Hydrocarbon Composition Reflects Genetic Relationship Among Colonies of the Introduced Termite Reticulitermes santonensis Feytaud

Nestmate recognition plays a key role in kin selection to maintain colony integrity in social insects. Previous studies have demonstrated that nestmate recognition is dependent on detection of cuticular hydrocarbons. However, the absence of intraspecific aggression between some colonies of Isoptera and social Hymenoptera questions whether kin recognition must occur in social insects. The purpose of this study was to determine if cuticular hydrocarbon similarity and high genetic relatedness could explain the lack of intraspecific aggression among and within colonies of the introduced subterranean termite Reticulitermes santonensis. We performed both GC analysis of cuticular hydrocarbons and genotyping by using 10 DNA microsatellite loci on the same 10 workers from each of 14 parisian colonies. Multivariate analyses demonstrated correspondence between cuticular hydrocarbon patterns and genetic variation. By using a redundancy analysis combining chemical and genetic data, we found that a few hydrocarbons (mainly short vs. long chains; saturated vs. unsaturated alkanes) were associated with most genetic variation. We also found a strong positive correlation between chemical and genetic distances between colonies, thus providing evidence of a genetic basis for cuticular hydrocarbon variation. However, genetic distance did not account for all chemical variation, thus suggesting that some hydrocarbon variation was environmentally derived. Investigation at the intracolony level indicated that cuticular hydrocarbons did not depend on colony social structure. Based on our findings, we speculate that the absence of intraspecific aggression in R. santonensis may result from a loss of diversity in genetically derived recognition compounds in this species that presumably descended from R. flavipes populations imported from North America.     

Trajectory tracking control of quadcopters under tunnel effects

There are many potential applications to utilise aerial robots in hazardous tunnel-like environments. For example, aiding human operators with inspections of small railway culverts or mineral mappings of mining tunnels. Nevertheless, such confined environments pose many challenges for quadcopters to navigate through. Suspended dust particles, poor lighting conditions and featureless/excessive features in the surroundings make localisation difficult. Furthermore, the fluid interactions between the rotors’ downwash and the surfaces of the surroundings create aerodynamic disturbances, which threaten the quadcopter’s stability and increase its risk of collision in the restricted confined space, not to mention the longitudinal wind gusts. This paper presents our findings on the characteristics of these aerodynamic disturbances, the Tunnel Effects for quadcopters, in a 1.5m(W) x 1.5m(H) square cross section tunnel through a series of experiments. A semi-autonomous system is proposed with self-stabilisation in the vertical and lateral axes while a pilot provides commands in heading and the longitudinal direction of the tunnel for performing required tasks such as tunnel wall inspections. We propose a cross-sectional localisation scheme using Hough Scan Matching with a simple kinematic Kalman filter for providing reliable vertical and lateral position information. An integral backstepping (IBS) controller is designed and implemented to enable quadcopters to robustly fly in tunnel-like confined environments. The proposed system is tested in simulated tunnel environments and a real railway tunnel with various reference trajectories, and the IBS controller has shown superior tracking performance in comparison with a PID controller despite of the existence of the Tunnel Effects.