新疆三种盐生植物种子萌发和幼苗早期生长对环境的适应对策

肉质小半灌木盐节木（Halocnemum strobilaceum）、里海盐爪爪（Kalidium capsicum）和盐爪爪（Kalidium foliatum）是中国西北盐生荒漠中分布的重要优势种植物。本文对生长在新疆盐漠环境中的三种植物种子的萌发生态学进行了研究。研究内容包括：（1）光照、温度对种子萌发的影响;（2）NaCl盐度对种子萌发和恢复、幼苗生长和恢复的影响;以及（3）低温层积处理对三种盐生植物种子休眠打破和耐盐性影响。 新成熟的盐节木、里海盐爪爪和盐爪爪种子都具有非深度生理休眠，它们分别需要经过4，4和8周的低温层积处理打破休眠。打破休眠的种子萌发的最适光温条件分别是25-30°C和光照（盐节木）;15-30°C，光照或黑暗（里海盐爪爪）;25°C和黑暗（盐爪爪）。 三种盐生植物的种子萌发对NaCl盐度胁迫有相似的响应，即低浓度不抑制萌发，高于一定浓度后，种子萌发随盐度的升高而逐渐降低，直至种子萌发被完全抑制。但是，开始抑制和完全抑制三种植物种子萌发的NaCl盐度是不同的。三种植物种子萌发受到抑制的起始浓度和种子萌发完全被抑制的盐度分别是：0.4和2.0 M（盐节木），0.2和0.6 M（里海盐爪爪），0.2和1.0 M（盐爪爪）。将未萌发的种子转入用蒸馏水饱和的滤纸上继续萌发，三种盐生植物的种子均有可恢复萌发的能力，经4.0 M NaCl处理后的种子，萌发恢复率都高于80%。三种植物的种子在蒸馏水中的总萌发率（在初始盐溶液中萌发的种子数与在蒸馏水中恢复萌发的种子数之和占所有供试种子数的百分率）高于各盐度条件下的种子总萌发率（在初始盐溶液中萌发的种子数与在蒸馏水中恢复萌发的种子数之和占所有供试种子数的百分率）。 盐节木和里海盐爪爪的种子萌发出的幼苗的早期生长对NaCl盐度胁迫有相似的响应，即随着盐度的升高，胚根的伸长逐渐降低;但是低盐度（≤0.4 M）不影响、甚至促进盐节木胚根的伸长，而各个盐度的NaCl均抑制里海盐爪爪的胚根伸长。盐节木的胚根生长较慢，在蒸馏水中培养24 h 后的根长< 1mm。低盐（0.2 M）促进胚根的伸长，但随盐度的继续升高（≥ 0.6 M），胚根伸长逐渐受到抑制，当盐度 ≥ 2.0 M NaCl时，盐节木胚根伸长完全停止。里海盐爪爪的胚根伸长快速，在蒸馏水中培养12 h后的平均根长为5 cm。低盐并不促进里海盐爪爪胚根的伸长，随盐度升高，胚根伸长逐渐受抑制。当盐度 ≥ 1.0 M NaCl时，里海盐爪爪的胚根伸长完全停止。但当转入蒸馏水中时，两种植物的胚根都可以继续伸长，伸长的能力随预处理盐溶液浓度的升高而降低，经 ≥ 4.0 M NaCl 预处理的盐节木胚根完全丧失继续伸长的能力;经0.6 M NaCl 预处理的里海盐爪爪胚根无法继续伸长。 低温层积处理对三种盐生植物的种子在NaCl溶液中的萌发均有显著促进作用。低温层积后，种子萌发可以发生的盐度范围提高;相同浓度NaCl溶液中，低温层积后的种子的萌发率和萌发速率都显著高于未经低温层积处理的种子。 实验结果表明三种盐生植物在种子萌发和早期幼苗生长阶段对盐生生境具有适应性。种子和幼苗早期在高盐分胁迫下保持的萌发恢复能力和胚根伸长生长的恢复能力是对盐生环境的特殊适应对策。这种适应对策有助于这三种植物在新疆的盐漠环境中得以成功的生存和繁衍。

Investigation of inclusions trapped inside Libyan Desert glass by Raman microscopy

Several specimens of Libyan Desert Glass (LDG), an enigmatic natural glass from Egypt, were subjected to investigation by micro-Raman spectroscopy. The spectra of inclusions inside the LDG samples were successfully measured through the layers of glass and the mineral species were identified on this basis. The presence of cristobalite as typical for high-temperature melt products was confirmed, together with co-existing quartz. TiO2 was determined in two polymorphic species, rutile and anatase. Micro-Raman spectroscopy proved also the presence of minerals unusual for high-temperature glasses such as anhydrite and aragonite.

How to tell the difference between a positive image and a stereotype: reading Priscilla, Queen of the Desert

This paper intervenes in critical discussions about the representation of homosexuality. Rejecting the ‘manifest content’ of films, it turns to cultural history to map those public discourses which close down the ways in which films can be discussed. With relation to The Adventures of Priscilla, Queen of the Desert, it examines discussions of the film in Australian newspapers (both queer and mainstream) and finds that while there is disagreement about the interpretation to be made of the film, the terms within which those interpretations can be made are quite rigid. A matrix based on similarity, difference and value provides a series of positions and a vocabulary (transgression, assimilation, positive images and stereotypes) through which to make sense of this film. The article suggests that this matrix, and the idea that similarity and difference provide a suitable axis for making sense of homosexual identity, are problematic in discussing homosexual representation.

Host location behaviour in the desert caterpillar, Heliothis punctifera

The host location behaviour of foraging caterpillars has received little attention, despite the wealth of theoretical and empirical studies that have been directed at this behavioural trait in adult Lepidoptera. Here, we study caterpillars of the moth Heliothis punctifera Walker (Lepidoptera: Noctuidae), which inhabits the arid inland desert areas of Australia. Caterpillars of this species consume many flowerheads before completing development and can be observed moving across the sand in search of new hosts. Consequently, if host location behaviour favours attraction to certain plant species, it might be expected to influence the distribution and abundance of caterpillars in the field. We present field data showing that H. punctifera caterpillars are unevenly distributed throughout mixed patches of two of its host species, with a higher abundance on Senecio gregorii F. Muell., the annual yellow top, compared to Myriocephalus stuartii (F. Muell. & Sond.) Benth., the poached egg daisy (both Asteraceae). Using laboratory studies, we test whether this distribution may, in part, be due to host location behaviour of caterpillars. Our results show that caterpillars exhibit a preference for locating S. gregorii in their pre- and post-contact foraging behaviour. In addition, our results provide evidence that feeding history plays a role in host location behaviour in this insect. We propose that key features of the desert environment and the ecology of H. punctifera would favour adaptations to host location behaviour by immatures.

Desert harmony : stories of collaboration between Indigenous musicians and university students

This article will discuss the ways in which community service learning programs in music can foster meaningful collaborations between universities and Indigenous communities. Drawing on recent pedagogical literature on service learning and insights from a four-year partnership between Australian Indigenous musicians at the Winanjjikari Music Centre in Tennant Creek and music students from Queensland Conservatorium Griffith University, it will describe how such programs can facilitate significant cross-cultural exchanges between students and Indigenous communities. By drawing on observations and interview data from those involved in the project, this paper argues that these partnerships can both assist communities with activities such as cultural maintenance, and provide students with intercultural experiences that have the potential to transform their understandings of Indigenous culture.

The origins and radiation of Australian Coptotermes termites: From rainforest to desert dwellers

The termite genus Coptotermes (Rhinotermitidae) is found in Asia, Africa, Central/South America and Australia, with greatest diversity in Asia. Some Coptotermes species are amongst the world’s most damaging invasive termites, but the genus is also significant for containing the most sophisticated mound-building termites outside the family Termitidae. These mound-building Coptotermes occur only in Australia. Despite its economic and evolutionary significance, the biogeographic history of the genus has not been well investigated, nor has the evolution of the Australian mound-building species. We present here the first phylogeny of the Australian Coptotermes to include representatives from all described species. We combined our new data with previously generated data to estimate the first phylogeny to include representatives from all continents where the genus is found. We also present the first estimation of divergence dates during the evolution of the genus. We found the Australian Coptotermes to be monophyletic and most closely related to the Asian Coptotermes, with considerable genetic diversity in some Australian taxa possibly representing undescribed species. The Australian mound-building species did not form a monophyletic clade. Our ancestral state reconstruction analysis indicated that the ancestral Australian Coptotermes was likely to have been a tree nester, and that mound-building behaviour has arisen multiple times. The Australian Coptotermes were found to have diversified ∼13 million years ago, which plausibly matches with the narrowing of the Arafura Sea allowing Asian taxa to cross into Australia. The first diverging Coptotermes group was found to be African, casting doubt on the previously raised hypothesis that the genus has an Asian origin.

Portrait of Albert Einstein in the Southern California desert Portraits; Men

Verso: "Er sinnt in der Wueste"

Salt in the desert: A comparison of clinical versus serum-calculated osmolality determination of dehydration

Background: Clinicians frequently use their own judgement to assess patient’s hydration status although there is limited evidence for the diagnostic utility of any individual clinical symptom. Hence, the aim of this study was to compare the diagnostic accuracy of clinically assessed dehydration in older hospital patients (using multiple symptoms), versus dehydration measured using serum-calculated osmolality (CO) as the reference standard. Method: Participants were 44 hospital patients aged ≥ 60 years. Dehydration was assessed clinically and pathologically (CO) within 24 hours of admission and at study exit. Indicators of diagnostic accuracy were calculated. Results: Clinicians identified 27% of patients as dehydrated at admission, and 19% at exit, compared to 19% and 16% using CO. Agreement between the measures was fair at admission and poor at exit. Clinical assessment showed poor sensitivity for predicting dehydration with reasonable specificity. Conclusions: Compared to the use of CO, clinical assessment of dehydration in older patients was poor. Given that failure to identify dehydration in this population may have serious consequences, we recommend that clinicians do not rely upon their own assessments without also using the reference standard.

Postcards from oases in the desert: phenomenology of SUSY with intermediate scales

The presence of new matter fields charged under the Standard Model gauge group at intermediate scales below the Grand Unification scale modifies the renormalization group evolution of the gauge couplings. This can in turn significantly change the running of the Minimal Supersymmetric Standard Model parameters, in particular the gaugino and the scalar masses. In the absence of new large Yukawa couplings we can parameterise all the intermediate scale models in terms of only two parameters controlling the size of the unified gauge coupling. As a consequence of the modified running, the low energy spectrum can be strongly affected with interesting phenomenological consequences. In particular, we show that scalar over gaugino mass ratios tend to increase and the regions of the parameter space with neutralino Dark Matter compatible with cosmological observations get drastically modified. Moreover, we discuss some observables that can be used to test the intermediate scale physics at the LHC in a wide class of models.

Lizards of the Thar Desert - Resource partitioning and community composition

How similar species co-exist in nature is a fundamental question in community ecology. Resource partitioning has been studied in desert lizard communities across four continents, but data from South Asia is lacking. We used area-constrained visual encounter surveys to study community composition and spatial and temporal resource partitioning in a lizard community during summer in the Thar Desert, western India, addressing an important biogeographic gap in knowledge. Twelve one-hectare grids divided into 25 m x 25 m plots were placed across four habitats barren dunes, stabilized dunes, grassland, and rocky hills. We recorded 1039 sightings of 12 species during 84 sampling sessions. Lizard abundance decreased in the order stabilized dunes > grassland > barren dunes > rocky hills; richness was in roughly the opposite order. Resource partitioning was examined for the seven commonest species. Overall spatial overlap was low (<0.6) between species pairs. Overlap was higher within habitats, but species showed finer separation through use of different microhabitat categories and specific spatial resources, as well as by positioning at different distances to vegetation. Diurnal species were also separated by peak time of activity. Space appears to be an important resource dimension facilitating coexistence in this desert lizard community. (C) 2015 Elsevier Ltd. All rights reserved.