Some Low Field Transport Properties of LPE grown GaAs and AlAs Mixed Alloys and Saxena's Deep Donor

GaAs and AlAs mixed crystals offer the possibilities of their potential applications in various modern optical, electrical and microwave heterostructure devices to realize complete systems performing various operations for both civil and defence operations. For x >~ 0.25, a deep level, known as Saxena's deep donor dominated the electrical characteristics of Ga/sub 1-x/Al/sub x/As crystals and its activation energy increases with x, being 0.170 eV at x = 0.44, the energy of this level below the X minima decreases with x, reaching a value of 0.106 eV at x = 0.78. The results show that the lowest energy indirect minima is L in GaAs lying 0.280 eV above the T-L cross-over composition is x = 0.47. A long lifetime (T < 50 K) photoconductivity effect is also observed, which is associated with the indirect nature of the deep level. An increase in photo-Hall mobility at low temperatures over the dark mobility shows that this level has the properties of an acceptor-like centre. Shallow donor levels are also present in the crystals, but are heavily compensated. The Hall to drift mobility ratio peaks near the direct-indirect minima cross-over composition and has a peak value of ~ 3.8 at x = 0.42

A Survey on Important Aspects of Information Retrieval

Information retrieval has become an important field of study and research under computer science due to the explosive growth of information available in the form of full text, hypertext, administrative text, directory, numeric or bibliographic text. The research work is going on various aspects of information retrieval systems so as to improve its efficiency and reliability. This paper presents a comprehensive survey discussing not only the emergence and evolution of information retrieval but also include different information retrieval models and some important aspects such as document representation, similarity measure and query expansion

In vitro biology of Columbicola bacillus (Phthiraptera: Ischnocera)

An ischnoceran louse, Columbicola bacillus infesting Ring dove, Streptopelia decaocto was subjected to in vitro experimentation. The data obtained through in vitro experimentation was utilized to construct the life table and to determine its intrinsic rate of natural increase (rm). The value of rm appeared to be 0.054. At this rate, the population of C. bacillus is supposed to be double after 12.95 days, indicating that it is moderate breeder

Population characteristics of Brueelia sp. on certain Indian Finches

Five kinds of finches were examined during 2004-06. Two kinds of finches were found infested with ischnoceran lice, Brueelia sp. (Prevalence-20.5%, mean intensity of infestation-4.7 and range of infestation, 1-23). The frequency distribution pattern of Brueelia sp. on Indian finches conformed to the negative binomial model. Sex ratio was skewed in favour of females and adults outnumbered the nymphs in natural population

Diagnostic features of three nymphal instars of Sturnidoecus bannoo (Phthiraptera: Ischnocera) infesting Bank Myna Acridotheres ginginianus

Three nymphal instars of bank Myna louse, Sturnidoecus bannoo differ from each other not only any size, abdominal segmentation, chitinization but also in the number of setae occurring on head, thorax and abdomen. Present report provides information on the diagnostic characters of three nymphal instars of the aforesaid louse

Population characteristics of Phthiraptera occurring on Red Whiskered Bulbul (Pycnonotus jocosus)

Two phthirapteran species, Menacanthus eurysternus (Amblycera) and Brueelia sp. (Ischnocera) were recovered from 100 Red Whiskered Bulbuls (Pycnonotus jocosus) during March to December 2006. The occurrence of both the phthirapteran species on the aforesaid host are new host records. The prevalence, intensity of infestation, range of infestation, variance to mean ratio, sex ratio, adult nymph ratio, index of discrepancy (D) and exponent of negative binomial (k) were computed. The frequency distribution pattern of M. eurysternus conforms to negative binomial model. The frequency distribution pattern of Brueelia sp. was skewed but not described by the negative binomial

Managing organizational DSS development in small manufacturing enterprise

A number of Hong Kong manufacturing companies have moved their production to the People's Republic of China while retaining their supporting functions (such as marketing, distribution, etc.) in Hong Kong. As a consequence, their mode of operation has become more complex and demands better production planning and control (PPC). One solution is to use an information system in which all factory resources are integrated within a single framework for PPC. The main instrument of this strategy is an Organizational DSS (ODSS). This paper presents a case study of development and adoption of an ODSS in a small manufacturing enterprise. Analysis of the findings highlights the cultural as well as organizational underpinnings and the need for effective intervention before and throughout the computerization. The implementation strategies are described, with emphasis on prerequisite infrastructural developments, showing how they provide opportunities and constraints

Bio-Ecology of the Louse, Upupicola upupae, Infesting the Common Hoopoe, Upupa epops

The population characteristics of the louse, Upupicola upupae (Shrank) (Mallophaga: Philopteridae: Ishnocera), infesting the Common Hoopae, Upupa epops L. (Aves: Upupiformes), were recorded during 2007–08 in District Rampur, Uttar Pradesh India. The pattern of frequency distribution of the louse conformed to the negative binomial model. The lice and its nits were reared in vitro at 35 ± 1° C, 75–82 % RH, on a feather diet. The data obtained was used to construct the life table and to determine the intrinsic rate of natural increase (0.035 female/day), the net reproductive rate was 3.67 female eggs/female, the generation time was 37 days, and the doubling time of the population was 19 days. The chaetotaxy of the three nymphal instars has also been noted to record their diagnostic characteristics. Information on egg morphology and antennal sensilla is also presented

In vitro and in vivo evaluation of 2-chloroethylnitrosourea derivatives as antitumor agents

Aim: To evaluate potential of Naphthal-NU, Napro-NU and 5-Nitro-naphthal-NU, 2-chloroethylnitrosourea compounds with substituted naphthalimide in the pre-clinical studies. Materials and Methods: In vitro cytotoxicity of three nitrosoureas was determined in human and mouse tumor cell lines by MTT assays. In vivo anti-tumor potential was evaluated in Sarcoma-180 (S-180) and Ehrlich’s carcinoma (EC) solid tumors. Apoptosis in S-180 cells was analyzed by using Annexin V-Propidium Iodide (PI). Histological analysis of liver and kidney was performed at optimum dose (50 mg/kg). Expression status of CD4+, CD8+ and CD25+ cells in treated mouse were also examined. Results: Significant tumor growth retardation by the compounds was noted in early and advanced disease groups, as the life span of drug treated mice increased considerably. Drug induced killing was observed by induction of apoptosis. Naphthal-NU and 5-Nitro-naphthal-NU were effective to normalize the tumor induced structural abnormalities of liver and kidney. The compounds have no immunotoxic effect on CD4+ and CD8+ T cells and down regulate CD4+CD25+ regulatory T cells. Conclusion: Overall data holds promise for the antitumor activity with lower toxicity of the compounds that can be utilized for the treatment of human malignant tumors. Key Words: cytotoxicity, Naphthal-NU, Napro-NU, 5-Nitro-naphthal-NU, Sarcoma-180, Ehrlich’s carcinoma

Ocean Colour Remote Sensing of Flood Plumes in the Great Barrier Reef

The objective of the research reported in this thesis was to develop a technique to monitor the dynamics of sediments and nutrients entering the coastal ocean with river plumes associated with high intensity low frequency events (e.g. floods), using ocean colour remote sensing. To achieve this objective, an inverse bio-optical model was developed, based on analytical and empirical relationships between concentrations of optically significant substances and remote sensing of water-leaving radiance. The model determines concentrations of water-colouring substances such as chlorophyll, suspended sediments, and coloured dissolved organic matter, as well as the values of optical parameters using water-leaving radiances derived from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). To solve atmospheric correction in coastal waters, the aerosol type over clear waters is transferred to adjacent turbid water pixels. The vicinity of the Herbert River, central Great Barrier Reef zone, Australia, was used as a case study for the application of the algorithm developed. The satellite ocean colour technique was successfully validated using sea-truth measurements of water-colouring constituents acquired in the area during various seasons throughout 2002-2004. A high correlation between chlorophyll and dissolved organic matter was found in the coastal waters of the region, and when the bio-optical model was constrained to make chlorophyll a function of dissolved organic matter, the relationship between in situ and satellite-derived data was substantially improved. With reliable retrieval of the major water-colouring constituents, the technique was subsequently applied to study fluxes of particulate and dissolved organic and inorganic matter following a flood event in the Herbert River during the austral summer of 1999. Extensive field observations covering a seasonal flood in the Herbert River in February 2004 revealed high sediment and nutrient exports from the river to the adjacent coastal waters during the flood event. Due to rapid settling, the bulk of the sediment-rich influx was deposited close inshore, while the majority of nutrients exported from the river were consumed by phytoplankton in a relatively small area of the coastal ocean. With the help of ocean colour remote sensing, it was demonstrated that river-borne sediments and nutrients discharged by a typical flood in the Herbert River are mostly precipitated or consumed within the first 20 km from the coast and therefore are unlikely to reach and possibly affect the midshelf coral reefs of this section of the Great Barrier Reef lagoon