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Terahertz (THz) radiation lies between the micro and far-infrared range in the electromagnetic spectrum. Compared with microwave and millimeter waves, it has a larger signal bandwidth and extremely narrow antenna beam. Thus, it is easier to achieve high-resolution for imaging and detection applications. The unique properties, such as penetration for majority non-polar materials, non-ionizing characteristic and the spectral fingerprint of materials, makes THz imaging an appealing artifice in the military, biomedical, astronomical communications, and other areas. However, THz radiation’s current low power level and detection sensitivity block THz imaging system from including fewer optical elements than the visible or infrared range. This leads to imaging resolution, contrast, and imaging field of view degenerate and makes the aberration more serious. THz imaging based on the space Fourier spectrum detection is developed in this thesis to achieve high-quality imaging. The main concept of Fourier imaging is by recording the field distribution in the Fourier plane (focal plane) of the imaging system; the information of the target is obtained. The numerical processing method is needed to extract the amplitude and phase information of the imaged target. With additional process, three-dimensional (3D) information can be obtained based on the phase information. The novel recording and reconstructing ways of the Fourier imaging system enables it to have a higher resolution, better contrast, and broader field of view than conventional imaging systems such as microscopy and plane to plane telescopic imaging system.
The work presented in this thesis consists of two imaging systems, one is working at 300 GHz based on the fundamental heterodyne detection of the THz radiation, the other is operated at 600 GHz by utilizing the sub harmonic heterodyne detection technique. The realization and test of the heterodyne detection are based on the THz antenna-coupled field-effect transistor (TeraFET) detector developed by Dr. Alvydas Lisauskas. Both systems use two synchronized electronic multiplier chains to radiate the THz waves. One radiation works as the local oscillator (LO), the other works as illumination with a slight frequency shift, the radiations are mixed on the detector scanning in the Fourier plane to record the complex Fourier spectrum of the imaged target. The LO has the same frequency range as the illuminating radiation for fundamental heterodyne detection but half the frequency range for the sub-harmonic heterodyne detection. The 2-mm resolution, 60-dB contrast, and 5.5-cm diameter imaging area at 300 GHz and the of 500-μm resolution, 40-dB contrast, and 3.5-cm diameter imaging area at 600 GHz are achieved (the 300-GHz illuminating radiation has the approximate power of 600 μW , the 600-GHz illuminating radiation has the approximate power of 60 μW ).
The thesis consists of 6 parts. After the introduction, the second chapter expands on the topic of Fourier optics from a theoretical point of view and the simulations of the Fourier imaging system. First, the theory of the electromagnetic field propagation in free space and through an optical system are investigated to elicit the Fourier transform function of the imaging system. The simulation is used for theoretical considerations and the implementation of a Fourier optic script that allows for numerical investigations on reconstruction. The preliminary imaging field of view and resolution are also demonstrated. The third chapter describes the Fourier imaging system at 300 GHz based on the fundamental heterodyne detection, including the experimental setup, the 2D, and 3D imaging results. The following fourth chapter reports the integration of the TeraFET detector with two substrate lenses (one is a Si lens on the back-side Si substrate, the other is a wax/PTFE lens on the front side containing the bonding wires) for sub-harmonic heterodyne detection at 600 GHz. The characteristic of the wax/PTFE lens at THz range is presented. After that, the compared imaging results between the detector with and without the wax/PTFE lens are shown. The fifth chapter extends the demonstration on the lateral and depth resolution of the Fourier imaging system in detail and uses the experimental results at 600 GHz to validate the analytical predictions. The comparison of the resolution between the Fourier imaging system and the conventional microscopy system proves that the Fourier imaging system has better imaging quality under the same system configuration. The last chapter in this thesis concludes on the findings of the THz Fourier imaging and gives an outlook for the enhancement of the Fourier imaging system at THz range.
Bumblebees (Bombus Latreille, 1802), because of their large body size, bright colours and activity at times and places that coincide with biologists, are an example of a group of insects that is particularly well represented in museum collections. This is important if taxonomic revisions are to achieve greater comparability among species. Bumblebees have also attracted particular attention because they are especially ecologically and economically valuable for pollination in north temperate regions, where they are now becoming increasingly threatened. I argue that the what, the where, and the how of effective conservation management may be informed by understanding the divergent characteristics that have affected their biogeographical past: by helping us to see ‘the woods’, not just ‘the trees’, of their habitat needs. Identifying suitable habitat should be part of reconstructing historical biogeography within taxonomic revisions. For bumblebees, for example, biogeographical analysis associates major taxonomic groups either with flower-rich lowland grasslands or with flower-rich montane grasslands, highlighting their contrasting requirements for: nest sites, flowers of different depths, pollen-plant families, and especially the differing importance of early spring and late summer flowers for breeding success. This broad view of species groups helps filter the less important idiosyncrasies from local case studies in order to focus conservation actions.
A new subgenus of Orinda Kirkaldy, 1907, Montorinda subgen. nov., is described to accommodate two new species from southeastern Queensland, O. (Montorinda) eungellana sp. nov. from Eungella National Park and O. (Montorinda) montana sp. nov. from Mount Walsh National Park. The new species are compared to the other species of the genus and a new subgenus Scapulorinda subgen. nov. is described to accommodate Orinda (Scapulorinda) scapularis (Jacobi, 1928), leaving a single species in the subgenus Orinda: O. (Orinda) lucindae (Kirkaldy, 1906). Illustrations of the male holotype, a female paratype and male genitalia are provided for both new species as well as habitus and wing of O. (Scapulorinda) scapularis (Jacobi, 1928), the most closely related species, for comparison. The type series of the O. (Montorinda) montana sp. nov. was collected on Grevillea whiteana Mc Gill. (Proteaceae). The genus Orinda is only recorded from Queensland and now contains four species.
Two new species of Palpimanus Dufour, 1820 are described from India: P. godawan Tripathi & Sankaran sp. nov. (♂♀), collected from the Thar Desert in Rajasthan, and P. maldhok Kuni, Tripathi & Sankaran sp. nov. (♂♀), collected from Maharashtra. Images of the endogyne and male palp of the holotype and paratype of P. narsinhmehtai Parajapati, Hun & Raval, 2021 are presented to facilitate its identification. A key to Indian species of Palpimanus and a catalogue of Indian palpimanid spiders are provided. The current distribution of all the known Indian palpimanid spiders is mapped.
Two species of leeches were described from Georgia in the past, Dina ratschaensis Kobakhidze, 1958 from the Racha-Lechkhumi and Kvemo Svaneti region and Trocheta ariescornuta Grosser, Barjadze & Maghradze, 2021 from the Samegrelo-Zemo Svaneti region. Both species were the only known typical representatives of cave leeches in Georgia. Recently, two more species of the genus Dina R. Blanchard, 1894 have been found in karst caves in this country. These leeches are morphologically similar to D. ratschaensis, from which they differ in the shape of the reproductive system, primarily the shape of the cornua of the genital atrium and the shape and extension of the vasa deferentia and ovisacs, justifying the description of two new species, Dina imeretiensis Grosser, Barjadze & Maghradze sp. nov. from the Imereti region and Dina samegreloensis Grosser, Barjadze & Shavadze sp. nov. from the Samegrelo-Zemo Svaneti region. Data on the cave dwelling invertebrate communities in the studied caves are provided. Molecular data are provided, and a phylogenetic tree based on Cox1 sequences of Dina spp. and related genera is provided and discussed.
The present work reviews the deep-water cone fauna of New Caledonia and its Economic Exclusive Zone. It is based on the material collected for more than 40 years by oceanographic expeditions in the deep waters surrounding New Caledonia, organized by the Muséum national d’histoire naturelle-Paris/ORSTOM, then Institut de Recherche pour le Développement, in the framework of the Tropical Deep-Sea Benthos programme. A total of 2377 lots containing 5113 specimens collected in depths between 100 and 1260 m have been examined. About 770 specimens were collected live, and allowed for radular and DNA studies. A phylogenetic analysis, based on the cox1 gene, of the deep-water cone snail fauna of New Caledonia is presented, along with a detailed, fully illustrated taxonomic account with data on geographic and bathymetric distribution and radular morphology. A total of 76 different species of cone snails were identified among the collected material. Of these, 22 corresponded to typical shallow water species, which were most likely translocated into deeper water, whereas 54 could be considered true components of the deep water (below 100 m) cone snail fauna. Species of the genus Profundiconus represent 22%, whereas those of the genera Conasprella and Conus represent 28% and 50%, respectively. Eleven deep water cone species can be considered as endemic to the New Caledonia EEZ, representing 20.3% of the total. The most abundant species found (more than 400 specimens each) were Conus (Afonsoconus) bruuni, Conasprella (Boucheticonus) alisi, Conasprella (Conasprella) boucheti, and Profundiconus vaubani. The new species Conus (Taranteconus) samadiae sp. nov. is hereby described.
The Australian genus of Eurybrachidae (Hemiptera, Fulgoromorpha) Kamabrachys gen. nov. is described to accommodate Platybrachys signata Distant, 1892 and Euronotobrachys plana Kirkaldy, 1906, the former being the type species. The new combinations Kamabrachys signata (Distant, 1892) gen. et comb. nov. and K. plana (Kirkaldy, 1906) gen. et comb. nov. are subsequently proposed. Ten new species are also included in the genus and described: K. andersoni gen. et sp. nov., K. brennani gen. et sp. nov., K. campbelli gen. et sp. nov., K. danielsi gen. et sp. nov., K. falcata gen. et sp. nov., K. fasciata gen. et sp. nov., K. pedemontana gen. et sp. nov., K. rieki gen. et sp. nov., K. v-carinatum gen. et sp. nov. and K. waineri gen. et sp. nov. The male and female genitalia of each species are illustrated and photographs of habitus, distribution maps, biological data and an identification key are provided. The mating behaviour of K. signata is described, illustrated and discussed. The genus Kamabrachys currently contains 12 species and is associated to trees in the family Myrtaceae.
Thylacocephalans are enigmatic euarthropods, known at least from the Silurian to the Cretaceous. Despite remaining uncertainties concerning their anatomy, key features can be recognised such as a shield enveloping most of the body, hypertrophied compound eyes, three pairs of raptorial appendages and a posterior trunk consisting of eight up to 22 segments bearing appendages and eight pairs of gills. Well-known for its euarthropod diversity, the La Voulte-sur-Rhône Lagerstätte (Callovian, Middle Jurassic, France) has provided many remains of four thylacocephalan species so far: Dollocaris ingens, Kilianicaris lerichei, Paraostenia voultensis and Clausocaris ribeti. In this paper, we study the type material as well as undescribed material. The re-description of La Voulte thylacocephalans reveals an unexpected diversity, with the description of two new species, Austriocaris secretanae sp. nov. and Paraclausocaris harpa gen. et sp. nov., and of specimens of Mayrocaris, a taxon originally described from Solnhofen Lagerstätten. We also reassign Clausocaris ribeti to Ostenocaris. The reappraisal of La Voulte thylacocephalans also provides important insight into the palaeobiology of Thylacocephala. New key anatomical features are described, such as an oval structure or a putative statocyst, which indicate a nektonic or nektobenthic lifestyle. Finally, we document a juvenile stage for Paraostenia voultensis.
The genera Colpixys and Xiphentedon are revised. Both genera are of Afrotropical distribution and are very similar to Entedon, but distinguished by a median strip or furrow on the propodeum replacing the median carina of Entedon. The genus Xiphentedon is characterized by the complete lateral propodeal sulci delimiting convex submedian areas, prosternum with a flange, axillula with indentate projection, and densely hairy central mesopectus. The subgenus Cederholmia Gumovsky, 1997 of Entedon is considered a junior synonym of Xiphentedon, so two of its species are moved to the genus as X. halli (Gumovsky, 1997) comb. nov. and X. danielssoni (Gumovsky, 1997) comb. nov. The genus Colpixys is characterized by the lack of characters of Xiphentedon, but also by the broadly sculptured propodeum with the deep median furrow delimited laterally by two sinuous margins. Three (one new) species are recognized in Colpixys and sixteen (thirteen new) species allocated to three groups (kayovei, danielssoni and forceps), are assigned to Xiphentedon. The new species are: Colpixys eburnus sp. nov. from Ivory Coast and the Republic of South Africa (RSA), Xiphentedon neserorum sp. nov. from RSA, X. simoni sp. nov. from Tanzania, X. dewittei sp. nov. and X. musimba sp. nov. from the Democratic Republic of the Congo (DRC), X. jeanyvesi sp. nov. from Tanzania, the Central African Republic (CAR) and RSA, X. wieringai sp. nov. from Gabon and Ivory Coast, X. kivuensis sp. nov. from DRC, X. palabora sp. nov. from RSA, X. sangha sp. nov. from CAR, X. nimba sp. nov. from Guinea, X. forceps sp. nov. from Ivory Coast, Benin and RSA, X. gerardi sp. nov. from Benin, DRC and RSA, and X. acutigena sp. nov. from Ivory Coast, DRC, Tanzania and RSA. Morphological peculiarities and possible relationships of Colpixys, Xiphentedon, Entedon and some other genera, are discussed.
Five species of the cheiracanthiid spider genus Cheiracanthium C.L. Koch, 1839 collected from China are diagnosed and described as new to science based on morphological characters: Cheiracanthium arcilongum sp. nov. (♂♀) from Yunnan, C. circulum sp. nov. (♂♀) from Yunnan, C. digitatum sp. nov. (♂♀) from Anhui, C. jiuquan sp. nov. (♂♀) from Guangxi and C. xinjiangense sp. nov. (♂♀) from Xinjiang. In addition, the photos of the habitus, copulatory organs and distribution map are provided for all species. However, DNA barcodes information is only provided for four species.
Madagascar is a freshwater biodiversity hotspot, yet the current understanding of freshwater bryozoan diversity is limited. Using a dissecting microscope, bryozoan statoblasts were collected during macrofossil analysis of a sediment core, which was taken from Lake Sofia, Madagascar, in 2019. There was a peak in the abundance of statoblasts prior to 1900, with 67 statoblast valves found at 45.5 cm and a decline in more recent sediments. A subsample of 14 specimens was examined under a scanning electron microscope to determine species identification. One of the species found was Plumatella kinesis. Two new species, Plumatella tsimiheta sp. nov. and Plumatella sofiae sp. nov. were also found and described. These results show the potential of lake sedimentary bryozoan remains for categorising species presence and distribution. Although poor preservation was a limitation for identification, there is still value in having a historical record of past biodiversity, especially when species may no longer be extant. This study highlights the need for further research to better understand the status of these species and other potential new species of bryozoan in Madagascar.
PURPOSE: This theoretical study seeks to understand how the development of ‘Transnational Business Feminism’ in response to the 2008 financial crisis, was implemented in 2013 through Japan’s ‘Womenomics’ program. The paper further examines how efficient this said form of neoliberal feminist economic program was in in addressing vulnerabilities in the Japanese financial system during the ongoing Covid-19 pandemic. Finally, it looks at how the pandemic has shifted conversations around the future of gender and finance in Japan through the Environmental, Social and Governance (ESG) framework.
DESIGN/METHOD: Drawing on a variety of sources, this paper uses a case study research methodology as well as statistical data from a variety of sources to draw theoretical conclusions on the specific case of Japan’s economy.
RESULTS/FINDINGS: This paper reveals that the programs implemented by the Japanese government failed to address existing gender inequalities and systemic risk in the Japanese economy, and that women in Japan were hit much harder by the repercussions of the pandemic, in spite of Womenomics policies.
ORIGINALITY/VALUE: This study offers insights into the effectiveness of neoliberal feminist agendas in addressing systemic financial and economic risk, in order to help optimize the potential of ESG.