Joint Color-Spatial-Directional clustering and Region Merging (JCSD-RM) for unsupervised RGB-D image segmentation

Recent advances in depth imaging sensors provide easy access to the synchronized depth with color, called RGB-D image. In this paper, we propose an unsupervised method for indoor RGB-D image segmentation and analysis. We consider a statistical image generation model based on the color and geometry of the scene. Our method consists of a joint color-spatial-directional clustering method followed by a statistical planar region merging method. We evaluate our method on the NYU depth database and compare it with existing unsupervised RGB-D segmentation methods. Results show that, it is comparable with the state of the art methods and it needs less computation time. Moreover, it opens interesting perspectives to fuse color and geometry in an unsupervised manner.Comment: submitted to the IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI

Shoot and plantlet regeneration from meristems of Dioscorea rotundata Poir and Dioscorea alata L.

In vitro culture media capable of regenerating moderate to high shoots and/or plantlets from meristems of two yam species - Dioscorea rotundata and Dioscorea alata within comparable duration of 10 weeks as commonly obtained in other monocots and root and tuber crops were investigated. The study comprised 125 phytohormone combinations investigated in three factorial experiments each consisting of an auxin (NAA) and a cytokinin (BAP or kinetin), or two cytokinins only. The frequency of direct plantlet regeneration, though significantly (P < 0.05) higher for D. alata than for D. rotundata, was low and ranged from 0 to 10% at 3 weeks after culture (WAC) and 0 to 35% at 8 WAC. At 8 WAC, shoot regeneration of 42-75% was obtained in D. rotundata in MS medium supplemented with 0.1 M NAA + 0.20 M BAP, and shoot + plantlet regeneration of 60-82% obtained in media containing 0.05 M + 0.20 M BAP or 0.46 M BAP + 0.50 M kinetin in D. alata. Both shoot induction and plantlet regeneration were species-dependent. Induced shoots were successfully rooted in MS medium within 3 to 4 weeks, bringing time taken for plantlet regeneration to 11 to 12 weeks. Regenerants were morphologically similar to the mother plants. Results of the present study will facilitate regeneration of plantlets via meristem in D. rotundata and D. alata

The electronic spectra of protonated PANH molecules

Aims. This study was designed to examine the viability of protonated nitrogen-substituted polycyclic aromatic hydrocarbons (H+PANHs) as candidates for the carriers of the diffuse interstellar bands (DIBs). Methods. We obtained the electronic spectra of two protonated PANH cations, protonated acridine and phenanthridine, using parent ion photo-fragment spectroscopy and generated theoretical electronic spectra using ab initio calculations. Results. We show that the spectra of the two species studied here do not correspond to known DIBs. However, based on the general properties derived from the spectra of these small protonated nitrogen-substituted PAHs, we propose that larger H+PANH cations represent good candidates for DIB carriers due to the expected positions of their electronic transitions in the UV-visible and their narrow spectral bands.Comment: 7 pages, 2 figures, accepted for publication in A&

Phosphorus nutrition of ectomycorrhizal and arbuscular mycorrhizal tree seedlings from a lowland tropical rain forest in Korup National Park, Cameroon

The relationship between mycorrhizal colonisation and phosphorus acquired by seedlings of the arbuscular mycorrhizal tree Oubanguia alata Bak f. (Scytopetalaceae) and the ectomycorrhizal tree Tetraberlinia moreliana Aubr. (Caesalpiniodeae) was evaluated at low and high inorganic phosphorus availability. AM colonisation was positively correlated with phosphorus uptake by O. alata at low, but not at high phosphorus availability. Seedlings growth was positively related to arbuscular mycorrhizal colonisation at both low and high phosphorus availability, suggesting that growth promotion by arbuscular mycorrhizas is not simply related to an increase of phosphorus uptake. In contrast, phosphorus uptake by T. moreliana was correlated with EM colonisation at both low and high phosphorus availability, but there was no relationship between growth and ectomycorrhizal colonisation. Promotion of phosphorus uptake by arbuscular mycorrhizas and ectomycorrhizas at low phosphorus availability is consistent with the co-occurrence of the two types of mycorrhiza in tropical rain forests where available soil phosphorus is low. However, ectomycorrhizal colonisation may also be of advantage where inputs of phosphorus rich litter raise the phosphorus status of the soil, as seen in the groves of ectomycorrhizal trees in Korup National Park, and may be one of the factors reinforcing local dominance by these trees

Recircumscription of the Nepenthes alata group (Caryophyllales: Nepenthaceae) in the Philippines : with four new species

An overview of Nepenthes in the Philippines is presented. Four new species, Nepenthes extincta sp. nov., N. kitanglad sp. nov., N. kurata sp. nov. and N. leyte sp. nov. are described and illustrated from the Philippines and placed in the Nepenthes alata group. An updated circumscription and key to the species of the group is provided. Delimitation and comparison with the Regiae group is given. All four of the newly described species are assessed as threatened using the International Union for the Conservation of Nature 2012 standard, and one, N. extincta sp. nov. is considered likely to be already extinct due to open-cast mining. Logging and conversion of forest habitat are thought to be the main threats to the other three species

Breeding for improved tuber quality in greater yam (Dioscorea alata L.)

Yams constitute an important staple food in tropical and subtropical regions. Dioscorea alata is one of the major cultivated species with a wide geographical distribution. It is currently second to D. rotundata in terms of production volume. Several traits of D. alata make it particularly valuable for economic production. These include high yield potential, ease of propagation, early growth vigor for weed suppression, and long storability of tubers. However, D. alata shows lower quality of pounded yam, the most consumer-preferred quality trait of yams in West Africa. The quality of yam tubers depends on many internal characters that determine their culinary and nutritional value (such as dry matter content, proteins, sugars, texture, flesh color) and some external characteristics (e.g. tuber size and shape). Conventional breeding for quality traits (boiled and pounded yam) is essentially carried out based on phenotypic observations and its difficult, costly and lengthy process. The partnership and studies that have been undertaken to improve the breeding efficacy for tuber quality in D.alata will be presented

Tree Species Composition and Forest Stratification along the Gradients in the Dry Deciduous Forests of Godavari Valley, Telangana, India

It is important to understand the tree species composition, abundance, species diversity and stratification in&nbsp;tropical dry deciduous forests that are under threat. A quadrat study was attempted in the dry deciduous forests&nbsp;along the ecological gradients in the Godavari Valley of northern Telangana, India. The study records the presence&nbsp;of 110 flowering plant taxa belonging to 82 genera and 37 families in 120 sampled plots, and there was&nbsp;enumeration of 15,192 individuals of ≥10 cm girth at breast height. Tectona grandis (teak) is the principal forest&nbsp;cover component in the region, which often formed pure stands in Adilabad and, to some extent, in Nizamabad&nbsp;districts. Further down to the Warangal district, teak was gradually replaced by Terminalia alata. Twenty tree&nbsp;species were found dominant at one place to the other, and the top 10 dominant taxa have shared nearly 41%&nbsp;of the total density of the forest cover. The tree relative density ranged from 0.007% to 20.84%. The values of&nbsp;Importance Value Index were between 0.245 (12 spp. including some exotics) and 32.6 (teak). These baseline&nbsp;data help to know the change detection along the gradients in the tropical forest ecosystem of a major river&nbsp;valley in the region and the drivers of change

Automatska izmjena alata na alatnim strojevima

Prilikom pisanja ovoga završnog rada dan je pregled suvremenih obradni sustava. U radu će biti prikazano kako su se od numerički upravljanih strojeva razvili obradni centri, koji posjeduju modul za automatsku izmjenu reznog alata. Također će se dati pregled načina automatske izmjene reznog alata na suvremenim numerički upravljanim alatnim strojevima, s posebnim osvrtom na uvjete koji su nužni za odvijanje automatske izmjene. Automatska izmjena alata kod glodaćih obradnih centara krenula je od revolverske glave sa 3 do 8 alata pa sve do raznih oblika lančanih magazina sa preko 200 alata. Automatska izmjena alat kod tokarskih obradnih centara krenula je također od revolverske glave sa 4 alata koja je razvojem dovedena do čak 20 alata. Kod automatske izmjene alata prikazan je način smještaja i izmjene alata, stezanja alata i vrste držača alata. Također su prikazani i višenamjenski alatni strojevi koji su kombinacija tokarskog i glodaćeg obradnog centra