Biology of the soldier caste in the termite genus Prorhinoterme (Isoptera: Rhinotermitidae)

Ontogeny of soldiers in Prorhinotermes simplex The soldiers were found to develop from larvae of the second up to the eighth instar, via a short (13-17 days) presoldier stage. The early soldier instars were found exclusively in incipient colonies while the mature colony contained late instar soldiers only. The first soldiers occur early in the incipient colonies; as soon as one year a er the establishment of these colonies a high proportion of soldiers was observed, which is comparable to that in mature colonies. The abrupt change in the external anatomy occurs in two steps. During the larva-presoldier moult, the head increases in length but only slightly in width. During the presoldier-soldier moult, both the length and width of the head increase markedly and the typical cordate shape is attained; the relative size of the pronotum increases considerably. The long falcate mandibles develop mainly during the larva-presoldier moult. One antennal segment is added during these two moults. With increasing instar age of soldiers a relative increase of the pronotum and the head size in its posterior region was observed. No functional differences in external anatomy were found among the six soldier instars. The composition of the frontal gland secretion is similar in the six soldier instars, an...CíIe Hlavním cíIem mojí dofuorcké práce bý popis rozmaniýh aspeků biologie kosý vojóka u rodu Prorhinotermes Silvestri, 7909 (lsoptera: Rhinotermitidae). Můj zájem o tento rod je motivovón u.ýjimečnýmirysy v jeho biologii a specifickou ýlogenetickou pozicí. Porozumnění biologii rodu Prorhinotermes je krokem k nalezení odpovědi na několik klíčoých otázek biologie termitťt,joko jsou: ,Je přítomnost kasý prauých dělníkú vskutku odvozeným jevem, jak bylo mnohoktút usuzováno? A uyvinula se tdto kasto v čeledi Rhinotermitidae z předkťt podobných rodu Prorhinotermes? Nebo existovola již u společných předků čeledi Rhinotermitidae o byla núsledně druhotně dmceno u rodu Prorhinotermes? A jaké vliuy zopříčinily tuto ztrátu?" Hledóní odpovědí no vo otózlgt spolu se zvědavostí povstóvající z mnoha dolších qýjimečnýchryrsůbiologie rodu Prorhinotermes sfo./7u zrodu velkého vědeckého zájmu o tento rod. liným zdrojem mojí motivace byl zdjem o foscinace kastou vojóka u termitů,jejížexistence je z mnoha pohledů unikótním jevem. Pod vlivem těchto inspimcí jsem se rozhodl zdměřit no vojólcy u rodu Prorhinotermes, kteří se zdojí hrót zásodní úlohu v jeho spoleěensfuích, Pokusil jsem se studovot úlohu vojóků s důrazem na ontogenezi a mortogenezi vojóků, populační dynamiku v raných koloniích, obranné schopnosti vojúků,jejich podíl...Department of ZoologyKatedra zoologieFaculty of SciencePřírodovědecká fakult

(3200) Phaethon: Bulk density from Yarkovsky drift detection

The recent close approach of the NEA (3200) Phaethon offered a rare opportunity to obtain high-quality observational data. We used the newly obtained optical light curves to improve the spin and shape model of Phaethon and to determine its surface physical properties derived by thermophysical modeling. We also used the available astrometric observations of Phaethon, including those obtained by the Arecibo radar and the Gaia spacecraft, to constrain the secular drift of the orbital semimajor axis. This constraint allowed us to estimate the bulk density by assuming that the drift is dominated by the Yarkovsky effect. We used the convex inversion model to derive the 3D shape model of Phaethon, and a detailed numerical approach for an accurate analysis of the Yarkovsky effect. We obtained a unique solution for Phaethon's pole orientation at $(318,-47)^{\circ}$ ecliptic longitude and latitude (uncertainty of $5^{\circ}$), and confirm the previously reported thermophysical properties ($D=5.1\pm0.2$ km, $\Gamma=600\pm200$ SI). Phaethon has a top-like shape with possible north-south asymmetry. The characteristic size of the regolith grains is 1-2 cm. The orbit analysis reveals a secular drift of the semimajor axis of $-(6.9\pm1.9)\times 10^{-4}$ au Myr$^{-1}$. With the derived volume-equivalent size of 5.1~km, the bulk density $\rho$ is $1.67\pm0.47$ g cm$^{-3}$. If the size is slightly larger $\sim5.7$ km, as suggested by radar data, $\rho$ would decrease to $1.48\pm0.42$ g cm$^{-3}$. We further investigated the suggestion that Phaethon may be in a cluster with asteroids (155140) 2005 UD and (225416) 1999 YC that was formed by rotational fission of a critically spinning parent body. Phaethon's $\rho$ is consistent with typical values for large ($>100$ km) C-complex asteroids and supports its association with asteroid (2) Pallas. These findings render a cometary origin unlikely for Phaethon.Comment: Accepted for publication in A&

Nickel: A micronutrient element for hydrogen-dependent growth of \u3ci\u3eRhizobium japonicum\u3c/i\u3e and for expression of urease activity in soybean leaves

Soybean plants and Rhizobium japonicum 122 DES, a hydrogen uptake-positive strain, were cultured in media purified to remove Ni. Supplemental Ni had no significant effect on the dry matter or total N content of plants. However, the addition of Ni to both nitrate-grown and symbiotically grown plants resulted in a 7- to 10-fold increase in urease activity (urea amidohydrolase, EC 3.5.1.5) in leaves and significantly increased the hydrogenase activity (EC 1.18.3.1) in isolated nodule bacteroids. When cultured under chemolithotrophic conditions, free-living R. japonicum required Ni for growth and for the expression of hydrogenase activity. Hydrogenase activity was minimal or not detectable in cells incubated either without Ni or with Ni and chloramphenicol. Ni is required for derepression of hydrogenase activity and apparently protein synthesis is necessary for the participation of Ni in hydrogenase expression. The addition of Cr, V, Sn, and Pb in place of Ni failed to stimulate the activity of hydrogenase in R. japonicum and urease in soybean leaves. The evidence indicates that Ni is an important micronutrient element in the biology of the soybean plant and R. japonicum

A 380 GHz SIS receiver using Nb/AlO(x)/Nb junctions for a radioastronomical balloon-borne experiment: PRONAOS

The superheterodyne detection technique used for the spectrometer instrument of the PRONAOS project will provide a very high spectral resolution (delta nu/nu = 10(exp -6)). The most critical components are those located at the front-end of the receiver: their contribution dominates the total noise of the receiver. Therefore, it is important to perform accurate studies for specific components, such as mixers and multipliers working in the submillimeter wave range. Difficulties in generating enough local oscillator (LO) power at high frequencies make SIS mixers very desirable for operation above 300 GHz. The low LO power requirements and the low noise temperature of these mixers are the primary reason for building an SIS receiver. This paper reports the successful fabrication of small (less than or equal to 1 sq micron) Nb/Al-O(x)/Nb junctions and arrays with excellent I-V characteristics and very good reliability, resulting in a low noise receiver performance measured in the 368/380 GHz frequency range

New insights into the coevolutionary history of termites and their gut flagellates: Description of Retractinympha glossotermitis gen. nov. sp. nov. (Retractinymphidae fam. nov.)

Lower termites harbor diverse consortia of symbiotic gut flagellates. Despite numerous evidence for co-cladogenesis, the evolutionary history of these associations remains unclear. Here, we present Retractinymphidae fam. nov., a monogeneric lineage of Trichonymphida from Serritermitidae. Although Retractinympha glossotermitis gen. nov. sp. nov. morphologically resembles members of the genus Pseudotrichonympha, phylogenetic analysis identified it as sister group of the Teranymphidae. We compared morphology and ultrastructure of R. glossotermitis to that of Pseudotrichonympha and other Teranymphidae, including the so-far undescribed Pseudotrichonympha solitaria sp. nov. from Termitogeton planus (Rhinotermitidae). Like all Teranymphidae, R. glossotermitis is a large, elongated flagellate with a bilaterally symmetric rostrum, an anterior, flagella-free operculum, and an internal rostral tube. However, it is readily distinguished by the length of its rostral flagella, which never exceeds that of the postrostral flagella, and its retractable anterior end. Inclusion of the hitherto unstudied Stylotermes halumicus (Stylotermitidae) in our survey of trichonymphid flagellates in Neoisoptera confirmed that the combined presence of Heliconympha and Retractinympha and absence of Pseudotrichonympha is unique to Serritermitidae. The close phylogenetic relatedness of Heliconympha in Serritermitidae to the spirotrichosomid flagellates in Stolotermitidae provides strong support for their acquisition by horizontal transmission

New insights into the coevolutionary history of termites and their gut flagellates: Description of Retractinympha glossotermitis gen. nov. sp. nov. (Retractinymphidae fam. nov.)

Lower termites harbor diverse consortia of symbiotic gut flagellates. Despite numerous evidence for co-cladogenesis, the evolutionary history of these associations remains unclear. Here, we present Retractinymphidae fam. nov., a monogeneric lineage of Trichonymphida from Serritermitidae. Although Retractinympha glossotermitis gen. nov. sp. nov. morphologically resembles members of the genus Pseudotrichonympha, phylogenetic analysis identified it as sister group of the Teranymphidae. We compared morphology and ultrastructure of R. glossotermitis to that of Pseudotrichonympha and other Teranymphidae, including the so-far undescribed Pseudotrichonympha solitaria sp. nov. from Termitogeton planus (Rhinotermitidae). Like all Teranymphidae, R. glossotermitis is a large, elongated flagellate with a bilaterally symmetric rostrum, an anterior, flagella-free operculum, and an internal rostral tube. However, it is readily distinguished by the length of its rostral flagella, which never exceeds that of the postrostral flagella, and its retractable anterior end. Inclusion of the hitherto unstudied Stylotermes halumicus (Stylotermitidae) in our survey of trichonymphid flagellates in Neoisoptera confirmed that the combined presence of Heliconympha and Retractinympha and absence of Pseudotrichonympha is unique to Serritermitidae. The close phylogenetic relatedness of Heliconympha in Serritermitidae to the spirotrichosomid flagellates in Stolotermitidae provides strong support for their acquisition by horizontal transmission

Application of ANN and PCA to two-phase flow evaluation using radioisotopes

In the two-phase flow measurements a method involving the absorption of gamma radiation can be applied among others. Analysis of the signals from the scintillation probes can be used to determine the number of flow parameters and to recognize flow structure. Three types of flow regimes as plug, bubble, and transitional plug – bubble flows were considered in this work. The article shows how features of the signals in the time and frequency domain can be used to build the artificial neural network (ANN) to recognize the structure of the gas-liquid flow in a horizontal pipeline. In order to reduce the number of signal features the principal component analysis (PCA) was used. It was found that the reduction of signals features allows for building a network with better performance