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  • Chemistry  (407,092)
  • Biochemistry and Biotechnology  (13,095)
  • Processing fishery products
  • Wiley-Blackwell  (407,082)
  • Lagos (Nigeria)  (23)
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  • 1
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23422 | 19325 | 2018-04-25 19:24:46 | 23422 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: Tilapia guineensis eggs were spawned and hatched in different salinities (17, 12, 7, 5, 2 and 0) ppt. The study was conducted in eight replicates. The aim of the investigation was to ascertain disparity in hatching size of Tilapia guineensis attributable to salinity. Immediately hatching was observed, body weight of five hatchlings in each replicate was individually weighed in milligramme. The individual total length of the five hatchlings was also measured in millimeter. The height of the yolk sac larva was determined with micro-metre screw gauge graduated in millimeter from the top of the yolk sac to the dorsal region of the larva. Data obtained were used to calculate yolk sac volume. Significant differences (P〈0.01) were observed in body weight and total length of larvae hatched in different salinities. The heaviest and longest larvae were hatched in 12 ppt saline water. The yolk sac volume of larvae hatched in lower salinities were significantly higher (P〈0.01) than the yolk sac volume of larvae hatched in higher salinities. The smallest yolk sac volume was recorded in 12ppt saline water. Our findings show that salinity could be manipulated for economic production of heavier seeds of Tilapia.
    Description: Includes:- 5 tables.;6 refs.
    Keywords: Aquaculture ; Chemistry ; Tilapia guineensis ; Nigeria ; brackishwater environment ; Salinity effects ; Larvae
    Repository Name: AquaDocs
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    Format: 51-55
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  • 2
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23440 | 19325 | 2018-05-02 08:25:12 | 23440 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The physical and chemical parameters of ABU Dam and Zaria Dam were carried out between September and October 2009. The results obtained in the two water bodies were temperature 27.7 0C, pH (7.5 and 7.3), dissolved oxygen (5.8 mg/l and 5.0 mg/l), biochemical oxygen demand (1.74 mg/l and 2. 16 mg/l), alkalinity (58 mg CaC03/l and 49 mgCaCO3/l) P04-P (2.47 mg/l and 1.59 mg/l) NO3-N (3.67 mg/l and 3.47 mg/l), conductivity (54.70 ~ks-1 and 42.48 ~ks-1), total hydrocarbon (TH) (47.66 mg/l) and 48.00 mg/l) and total dissolved solids (32.68 mg/l and 25.35 mg/l) respectively. There was no significant difference in the mean values of the parameters (P〉0.05) except conductivity and total dissolved solids. The water bodies were found to be neutral with high conductivity. All the properties in the water bodies were in conformity with international standards both for drinking and aquatic life.
    Description: Includes:- 2 tables.;7 refs.
    Keywords: Chemistry ; Limnology ; Pollution ; Nigeria ; Zaria Dam ; Nigeria ; ABU Dam ; freshwater environment ; Physicochemical properties ; Pollution
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    Format: 144-146
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  • 3
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23442 | 19325 | 2018-05-02 08:28:15 | 23442 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: In recent times there has been an upsurge in the culture of Tilapia in Nigeria resulting in increased demand for the fingerlings which is hardly satisfied. This is due to increasing demand for table size tilapia as food fish and under-sized tilapia in the fish meal and fish canning industries in Nigeria. Collection of Tilapia guineensis fingerlings from the wild, to augment hatchery production, has been the practice and this is subject to environmental fluctuations. Multivariate regression and correlation analyses of accumulated data were used to investigate the effects of changes in water quality parameters on abundance of fingerlings of Tilapia guineensis in a brackishwater habitat in Lagos. Dissolved oxygen (DO), salinity and secchi transparency were found to be the most dominant factors affecting the abundance of Tilapia guineensis fingerlings in the Lagos lagoon. Peak period of abundance was closely associated with period of low salinity (0.50%o to 5.60%o), which coincided with the period of low transparency and low DO in the rainy season. The correlation analyses of Tilapia guineensis fingerlings with the water quality parameters yielded the following correlation coefficients (r)- 0.598; (salinity); -0.644 (transparency); -0.710 (DO); -0.566; (temperature) and 0.129 (pH). The abundance of Tilapia guineensis fingerlings in the Lagoon was ultimately defined by a suitable regression equation. This result is expected to optimize the collection of fingerlings of Tilapia guineensis from the wild and boost food fish security in Nigeria and elsewhere.
    Description: Includes:- 1 table.;1 fig.;( refs.
    Keywords: Chemistry ; Fisheries ; Tilapia guineensis ; Nigeria ; Port Harcourt ; brackishwater environment ; Water quality ; Fingerlings ; Chemical properties ; Physicochemical properties
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    Format: 153-157
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  • 4
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23445 | 19325 | 2018-05-02 08:32:33 | 23445 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: Spatial and temporal variations of physico-chemical variables of Onu-Iyi ?Ukwu stream were studied for 12 months from March 2005 to February 2006. Three sampling stations were established along the main stream channel from source to mouth. Spatial variation in physico-chemical parameters indicated that total alkalinity, total hardness, conductivity, and nitrate-nitrogen (NO3) recorded their highest values at the upper reaches (with values 14.0mg/l, 88.09mg/l, 17.00~kscmiscm, and 0.60mg/l respectively). Dissolved Oxygen (DO) and pH had their maximum values of 8.20mg/l and 6.94 at the middle reaches. Turbidity, biochemical oxygen demand (BOD), temperature and phosphate-phosphorus (PO4) increased steadily from source to mouth. The observed seasonal variation indicated that wet season values were higher for all the parameters except temperature, turbidity, phosphate-phosphorus (PO4) and total alkalinity although the values were not statistically significant at p〉0.05. The correlation coefficient (r) showed no significant relationships p〈0.05 between physico-chemical parameters except DO and BOD with correlation values of (0.75 and -0.54) respectively.
    Description: includes:- 2 tables.;1 fig.;17 refs.
    Keywords: Chemistry ; Limnology ; Nigeria ; Onu-Iyi-Uku Stream ; freshwater environment ; Physicochemical properties ; Phosphates ; Phosphorus ; Turbidity
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    Format: 174-180
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  • 5
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23449 | 19325 | 2018-05-02 08:39:20 | 23449 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The physico-chemical parameters of Bosso Dam were analyzed weekly for a period of six (6) weeks from 29th October, 2009. In all, six (6) stations were identified within the dam. The physico-chemical parameters assessed were: temperature, dissolved oxygen, pH, alkalinity, hardness, conductivity and transparency. The results obtained from the analysis revealed slight variations in most parameters. There was no significant difference p〉0.05 in pH regardless of stations and weeks. But significant difference p〉0.05 were observed in dissolved oxygen, nitrate, temperature, conductivity, hardness, alkalinity, biological oxygen demand, transparency, in respect regard to stations. These variations could be due to influx of organic waste from surface run offs and inorganic waste deposited by man. The physico-chemical parameters observed, indicated that most of them fall with the recommended range or standard by the Federal Ministry of Environment
    Description: Includes:- 2 tables.;10 figs.;18 refs.
    Keywords: Chemistry ; Limnology ; Nigeria ; Bosso dam ; freshwater environment ; Physicochemical properties ; Chemical properties ; Physical properties ; Water properties
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  • 6
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23491 | 19325 | 2018-05-06 13:02:08 | 23491 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: This study evaluated the effect of varying smoking durations of 6, 6.5, 7 and 7.5 hours on the microbiological quality and percentage moisture content of cold-smoked Atlantic Cod, Gadus morhua. The fish sample were cold-smoked using the traditional drum oven. Four batches of the smoked fish were stored in metal baskets at ambient temperatures for a period of 12 days and assessed for Staphylococcus aureus and Escherichia coli loads, Mould count, Total Plate Count and Total Coliform Count. Analyses of the smoked fish samples were carried out at the initial stage (day 0) and subsequently every alternate days (i.e. days 2, 4, 6, 8, 10 and 12). Significant variations (P 〈 0.05) were obtained for all the microbial counts on the four smoked fish samples. The best microbiologically stable cold-smoked samples were that smoked at the longest duration of 7.5 hours. This produced the least mean microbial load range of TPC (1.50 x 103 - 2.00 x 105cfu/g); TCC varied from 0.0MPN/g to 12.0 MPN/g ; Mould count (1.32 x103 - 2.55 x 105 cfu/g) and Staphylococcus aureus (3.0 x103 - 1.35 x 105cfu/g) while percentage moisture content ranged between 25.3% to 15.2%. All the samples tested negative to Escherichia coli.
    Description: Includes:- 2 tables.;15 refs.
    Keywords: Fisheries ; Gadus morhua ; Nigeria ; Ogun State ; marine environment ; Microbial contamination ; Curing ; Processing fishery products
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    Format: 459-464
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  • 7
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23515 | 19325 | 2018-05-08 15:42:14 | 23515 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The paper examined gender and fisheries of Lake Kainji, Nigeria. The study highlights socio economic characteristics of women involved in Kainji Lake fisheries, important issues about gender and fisheries. It reveals that the categories of women in the Kainji Lake fisheries are in the middle age of 31 to 40 years with very low educational background. It also indicates that fish processing has been the most prominent activity of women in fisheries of Lake Kainji and constitute about 60 percent of the women. The study concludes that women play significant roles in all aspects of fisheries in Lake Kainji. Importantly, women’s roles span reproduction and production.
    Description: Includes:- 1 table;! fig.;13 refs.
    Keywords: Fisheries ; Nigeria ; Kainji L. ; freshwater environment ; Women ; Fisheries ; Processing fishery products
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    Format: 590-595
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  • 8
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24178 | 19325 | 2018-05-13 19:03:41 | 24178 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: The kilishi of Heterotis niloticus was produced for determination of appropriate slurry formulations for fish kilishi preparation. Thirty six freshly caught samples of H. niloticus with average weight of 306.20 ~c 18.33g, kilishi of this species was prepared with three different slurry formulations of high (F1), medium (F2) and low (F3) proportions of groundnut dough to spice mixture in the ratio of 1.3: 1.0, 1.0: 1.2 and 1.0: 1.8, respectively. Results of proximate composition indicated that kilishi of the H. niloticus prepared with formulation 3 (F3) recorded significantly higher (p〈0.05) protein content (54.22 ~c 0.01 %) and lower lipid content (8.00 ~c 0.00%), despite recording significantly higher (p〈0.05) moisture content (9.93 ~c 0.07%). Sensory score of kilishi of H. niloticus processed with F3 formulation rated significantly higher (p〈0.05) for taste, flavour and general acceptability with mean scores of 5.94 ~c 0.21,5.77 ~c 0.20 and 5.50 ~c 0.22, respectively. It could be concluded that kilishi of H. niloticus prepared with F3 formulation was the most acceptable hence, recommended for use in kilishi production.
    Description: Includes: 4 tables.;Also includes: 20 references.
    Keywords: Fisheries ; Heterotis niloticus ; Nigeria ; Sokoto ; Kilishi ; Heterotis niloticus ; Spices ; Proximate analysis ; Organoleptic assessment ; freshwater environment ; Freshwater fish ; Fishery products ; Processing fishery products ; Drying ; Packing fishery products ; Organoleptic properties ; Water content ; Enzymes ; Microorganisms
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  • 9
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24590 | 19325 | 2018-05-20 16:05:58 | 24590 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: The water analysis of five selected ponds in Ado-Ekiti in Ekiti State, was carried out to determine their suitability for fish culture. Pa rameters analyzed were: Temperature, Turbidity, Carbon (IV) oxide, Alkalinity, Hardness, pH and Dissolved oxygen. Values for temperature ranged between 20.0~'C and 29.0~'C, Turbidity values were between 46.0-50.2cm, Carbon (IV) oxide: 11.5-12.2mg/litre; alkalinity: 100-120mg/liter; hardness: 110-200mg/litre; pH: 6.8-7.8 and dissolved oxygen: 5.8-6.8mg/liter. The values obtained were found to be within acceptable range for fish production.
    Description: Includes: 10 references.
    Keywords: Aquaculture ; Chemistry ; Nigeria ; Physico-chemical parameter ; Fish pond ; Ado-Ekiti ; Fish production ; freshwater environment ; automation
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  • 10
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24618 | 19325 | 2018-05-22 06:12:36 | 24618 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: One of the priority research projects of the Nigerian Institute for Oceanography and Marine Research (NIOMR) is broodstock development and mass propagation of silver catfish, Chrysichthys nigrodigitatus of which the broodstock is naturally abundant in New Gala River. Selected physical characteristics and water physico-chemical parameters of the upper reach of the New Calabar River at Aluu were investigated. The highest depth value of 9.20 m was recorded in the middle of the river. The width of the river measured during spring high tide and low tide were 174 m and 110 m respectively. The cross-sectional area and average flow velocity of the river were 797.13 m2 and 0.374 m/s respectively. The discharge of the river was computed as 298.13m3/s. The river water was acidic most of the period (Hydrogen ion concentration, pH: 5.12 to 7.43), with low total alkalinity values (4.00 to 12.00 mgCaCO3/L) and low total hardness values (11.5 to 51.2 mgCaCO3/L) which indicate that the river water is black and soft. There was significant (p~,0.05) seasonal variation in temperature (23.1 to 31.7~'C\}, Secchi transparency (9.30 to 19.00 cm), total hardness (11.5 to 51.2 mgCaCO3/L), dissolved oxygen (5.20 to 7.50 mg/L) and dissolved oxygen deficit (0.02 to 2.95mg/L). These results are useful for several stake holders who use the river as a sink for trade wastes, as source of water for fish farming, as source of broodstocks of Chrysichthys nigrodigitatus, as raw water for water treatment plants, and as means of transportation of industrial materials.
    Description: Includes: 16 references.
    Keywords: Chemistry ; Fisheries ; Limnology ; Chrysichthys nigrodigitatus ; Nigeria ; New Calabar River ; New calabar River ; Physical characteristics and physico-chemical features ; Seasonal variation ; freshwater environment ; automation
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  • 11
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24619 | 19325 | 2018-05-22 06:14:16 | 24619 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Eight month physicochemical study of Dadin Kowa Dam was carried out forthnightly from July, 2011 to february 2012. Air temperature ranged from 18.25~'C ~c 28~'C ~c 0.50 to 28~'C ~c 2.16. Water tmperature ranged from 18.75~'C ~c 2.21. Transparency ranged from 11.00cm ~c 1.83 to 29.63 cm ~c ~c 2.14. Conductivity ranged from 13.00~Ks/cm ~c 13.33 to 41.38~Ks/cm ~c 5.54. Hydrogen ion (pH) ranged from 6.69 ~c 1.03 to 8.39 ~c 1.17. Dissolved oxygen ranged from 6.39mg/l ~c 1.03 to 10.14mg/l ~c 1.17. Total alkalinity ranged from o.69mg/l ~c 0.38 1.34mb/l ~c 0.02. Total ammonia ranged from 0.20mg/l ~c 0.027 to 0.83mg/l ~c 0.05. There were various levels of correlation between these parameters. There was no significant difference between both sites and months (p〉0.05) of all the parameters except total nitrogen which show a significant difference between the sites (p〈0.05) and transparency also shows a significance between the months (p〈0.05). All physicochemical parameters were almost within the tolerable limits for supporting aquatic life.
    Description: Includes: 27 references.
    Keywords: Fisheries ; Chemistry ; Nigeria ; Dadin Kowa Dam ; Physico-chemical parameters ; Fish production ; Dadin Kowa Dam ; freshwater environment ; automation
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  • 12
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23488 | 19325 | 2018-05-06 12:56:50 | 23488 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: Quality deterioration (microbial load) of smoked white catfish (Chrysichthys nigrodigitatus) from Ekeonunwa market Imo state Nigeria, was studied for six weeks. The experimental fish was divided into two batches. One batch of 18 fishes with average weight of 700g was resmoked weekly at 75oC. the second batch of 18 fishes weighing an average of 750g was left unresmoked. Weekly samples of both unresmoked and resmoked fish were taken from different regions (body flanks, gill and gut) and analyzed in the laboratory. Total plate counts (TPC) for the bacterial organisms in both resmoked and unresmoked samples (Table III) ranging between 1.56 105 and TNTC ( too numereous to count) exceeded the range of specified microbiological limits recommended for fish and fishery products by ICMSF (1986). Pathogenic organisms isolated included Escherichia coli, Staphylococcus aureus, Lysteria monocytogenes, Bacillus cereus, Aspergillus flavus, Penicillium varrucossum, Yeast and Mucor. Both unresmoked and resmoked fish specimens were contaminated with these spoilage microbes, but the microbial load of the resmoked samples were less than those of the unresmoked samples. Resmoking beneficially reduces microbial load of stored fish, increases the shelf/storage life, but can not totally eliminate pathogens. The presence of pathogens raises a public health concern.
    Description: Includes:- 3 tables.;1 fig.;10 refs.
    Keywords: Fisheries ; Chrysichthys nigrodigitatus ; Nigeria ; Imo State ; freshwater environment ; Processing fishery products ; Curing ; Microbial contamination ; Microorganisms ; Infestation ; Fish storage
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  • 13
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23460 | 19325 | 2018-05-05 12:31:34 | 23460 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The morphometric characters of Cynothrissa mento from three major Lagoons (Ologe, Badagry and Epe) in Lagos, Nigeria were compared to assess the possibility of this fish species from the three Lagoons belonging to the same sub-population. The length-weight relationships (LWR), and condition factors (CF) of the fish were also described as well as the physico-chemical parameters of the three water bodies. The study was conducted between May, 2009 and April, 2010 and monthly sampling of fish and water was done in each sampling site. Seven7 physico-chemical parameters were assessed and these are; temperature, pH, salinity, turbidity, dissolved oxygen, total alkalinity and total hardness. A total of 294 specimens (Ologe 60, Badagry 174 and Epe 60) of C. mento were collected from the landings of the local fisher folks from the sampling sites. Seven morphometric characters; total length (TL), standard length (SL), body depth (BD), head length (HL), head depth (HD), eye diameter (ED) and interorbital width (IW) were measured. There was no significant difference (p 〉 0.05) in all the physico-chemical parameters measured among the sampling sites except pH. Coefficient of difference revealed that the C. mento from the three lagoons are uniform in all the morphometric parameters examined, which means that the specimens from the three sampling sites do not belong to different sub-populations. The growth coefficient/slope (b) values obtained for the fish species from the sampling sites ranged from 2.27 - 2.53, and differed significantly (p 〈 0.05) from 3, which indicates that most of the fish species have negative algometric growth.
    Description: Includes:- 4 tables.;1 fig.;24 refs.
    Keywords: Ecology ; Chemistry ; Cynothrissa mento ; Nigeria ; Ologe Lagoon ; Nigeria ; Badagry Lagoon ; Nigeria Epe Lagoon ; marine environment ; Population dynamics ; Morphometry ; Check lists ; Length-weight relationships ; Condition factor ; Physicochemical properties
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  • 14
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23489 | 19325 | 2018-05-06 12:58:47 | 23489 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: Bacteria flora predominates the skin of freshly caught fish, and will invade the tissue of the fish immediately after catch. Two preservative methods (cold smoking and freezing) were used to store eighteen specimens of Chrysichthys furcatus harvested from River Niger at Cable-point, Asaba. Two specimens were randomly selected every day from the cold smoked specimens and on weekly basis from the frozen specimens for physical, chemical and biological examination for bacteria causing spoilage. Five bacteria isolates: Salmonella spp, Vibrio cholera, Escherichia coli, Staphylococcus aureus and Proteus vulgaris, were identified. Physical observation of the cold smoked fish after 24 hours showed the production of gas, off-odor, off flavour and slime formation. The colony forming units (CFU) of bacteria isolated from the fish immediately after harvest was 116 x 109 cfu/g. It increased to 268 x 109 cfu/g after 4 days of preservation, and to 64 x 109 cfu/g after four weeks of preservation. The Chi square (X2) analysis revealed that there was a significant difference between the bacteria load of frozen and cold smoked specimens. Free fatty acid value immediately after harvest was 0.90 %. It increased to 2.24 % after four weeks in the freezer and 2.35 % after four days of cold smoked storage. The Total Volatile Nitrogen profile at harvest time was 15.3 mgN/100g. It increased to 35.2 mgN/100g after four days, (for the cold smoked specimens) and 26.3 mgN/100g (for the frozen specimens) after four weeks. The peroxide and hydrogen ion concentrations followed the same increasing trend. The study revealed that freezer preservation was better than the cold smoked one. This is because bacteria proliferation was reduced and or halted in the frozen specimens, whereas it encouraged rapid bacteria growth in the cold smoked fish. The production of total volatile nitrogen (TVN), free fatty acid (FFA), peroxide value (PV) and hydrogen ion concentration (pH) was higher in the cold smoked specimens than in frozen ones, hence the cold smoked specimen exhibited shorter shelf life than their frozen specimens.
    Description: Includes:- 4 tables.;15 refs.
    Keywords: Fisheries ; Chrysichthys furcatus ; Nigeria ; Niger R. ; freshwater environment ; Infestation ; Fish storage ; Microbial contamination ; Chemical degradation ; Chemical reactions ; Biological damage ; Damage ; Processing fishery products
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  • 15
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23497 | 19325 | 2018-05-07 12:17:33 | 23497 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The changes that occur on proximate composition of some common fish processing methods used in Nigeria were studied in order to determine the nutritional content of the processed products. Traditional (smoke drying and sun drying) and modern (electrical oven drying) methods of processing were used to process Pseudotholithus elongatus and the results were compared with the fresh sample to determine the changes that occur during processing. The results for the fresh sample of P. elongatus were 79.50%, 1.50%, 0.8% and 18.2% for moisture, ash, lipid and protein. For the processed products, the moisture content for smoke-dried, sun-dried, salt sun-dried and oven-dried fish were 27.00%, 21.83%, 19.50% and 20.17% . Oven dried had the highest protein content (69.87%) while salt sun-dried had the lowest (54.90%). Lipid content was highest in sun-dried (6.6%) and lowest in smoke-dried (4.6%). Correlation between smoke-dried and sun-dried were r2 = 0.99, smoke-dried and oven-dried were r2= 0.98 and smoke-dried and salt sun-dried were r2= 0.98. There was no correlation between the fresh and the processed P.elongatus. The present findings revealed that processing affect the nutritional composition of fish.
    Description: Includes:- 1 table.;22 refs.
    Keywords: Fisheries ; Health ; Pseudotolithus elongatus ; Nigeria Lagos ; Proximate composition ; freshwater environment ; Processing fishery products ; Moisture ; Proteins ; Chemical analysis ; Lipids
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  • 16
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23495 | 19325 | 2018-05-07 12:13:48 | 23495 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The effects of fresh garlic (Allium sativum) at concentrations of 0 g/kg (control), 10 g/kg, 30 g/kg and 50 g/kg of fish on lipid oxidation and microbial growth of hot smoked catfish Clarias gariepinus during a 28 day storage period at ambient temperature of 20-260C was examined. The samples were subjected to chemical and microbial analyses during the storage period. The results of analyses suggest that fresh garlic possesses antioxidant and antimicrobial properties, which can extend the shelf life of Clarias gariepinus.
    Description: Includes:- 1 table.;2 figs.;6 refs.
    Keywords: Fisheries ; Clarias gariepinus ; Nigeria ; Garlic ; freshwater environment ; Chemical analysis ; Chemical composition ; Microbiological analysis ; Processing fishery products ; Preservatives ; Fish storage ; Storage conditions ; Storage effects ; Storage life ; Shellfish
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  • 17
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23490 | 19325 | 2018-05-06 13:00:41 | 23490 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: The effects of groundnut oil and sodium chloride as protectants against insect infestation of dried fish were investigated for a period of 13 weeks. The fish samples were divided into 3 groups, a group was soaked for 10mins in 30% sodium chloride solution (Brine), and the second group was dipped in groundnut oil after smoking while the third group served as control. The samples were kept in different containers in the laboratory at temperature of 28oC and 70% Relative humidity for 13 weeks. Results show that, the fish treated with 30% sodium chloride was effectively protected from insect and moulds compared to sample treated with groundnut oil. The odour and the texture were also more attractive to customers. However, fish treated with groundnut oil was attacked by insects at week 12th and 13th with 6 Maculatus, 4 Necrobia rufipes species and at few mould colonies. The control specimens however was attacked by insects from week 8th to 13th with numerous number of both Necrobia rufipes and Maculatus species as well as mould colonies showing as early as from the 6th week. The results proved that sodium chloride is more effective than groundnut oil for long period of storage.
    Description: Includes:- 5 tables.;5 refs.
    Keywords: Fisheries ; Nigeria ; Kainji L. ; Groundnut oil ; freshwater environment ; Infestation ; Processing fishery products ; Fish storage ; Sodium chloride
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  • 18
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    Fisheries Society of Nigeria | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/23522 | 19325 | 2018-05-09 12:25:25 | 23522 | Fisheries Society of Nigeria
    Publication Date: 2021-07-14
    Description: Women are the majority of the third World population. They are considered subservient to their male counterpart, even in Europe and America where women have greater basic human right. This paper evaluates the various roles of women in Fisheries and fish processing. Statistics from the European Union shows that, of the various fishing sectors, participation of women (in terms of number) was greatest in fish processing, followed by marine aquaculture, marine fishing and inland aquaculture, with no women involved in inland fishing. In Asia and Africa women are basically involved in fish processing and marketing. In Asia (Thailand and Philippines), women are involved in hatchery operations in aquaculture in addition to fish processing. The finding of the review shows that Fish processing in developing countries, principally Africa is not attracting young literate generation who may have better management competence. It further revealed that, in Nigeria women are directly involved in capture fishery, in addition to fish marketing and processing. This is aimed at empowering women economically to meet the pressing needs of the family. The paper further assesses the problems of women in fisheries and fish processing namely, access to financial resources, education, support services and the need to ensure food security. Possible ways of improving women’s participation in fisheries were highlighted.
    Description: Includes:-1 table.;23 refs.
    Keywords: Fisheries ; Nigeria ; freshwater environment ; Women ; Processing fishery products
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  • 19
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24197 | 19325 | 2018-05-16 15:16:21 | 24197 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: The effects of two different preservative methods, NIOMR Smoking Kiln and Oven drying on Crude Protein minerals and Vitamin of clarias gariepinus were studied. Clarias gariepinus were obtained from the fish farm of African Regional Aquaculture Centre, Aluu, Port Harcourt. The crude protein, minerals and vitamins of the fresh fish were determined immediately while two other batches were separately dried using oven at 50~'C for 30minutes and NIOMR Smoking Kiln at 70~'C for 3 hours. Result of the crude protien of fresh fish was 21.84 ~c 1.10 which increased to 59.53 ~c 1.88 and 35.41 ~c 1.00 in both NIOMR smoking and oven, respectively. This means that, there was a significant different in both dryers on the crude protein. This will improve the knowledge and capacity of rural women and agricultural communities on the appropriate processing method for fish. The mineral and vitamins of oven dried and NIOMR Smoking kiln were analyzed. The vitamin content of both the fish, dried and smoking kiln shows no significant different except in vitamin A which was significant (p〈0.05).There was significant different (p〈0.05) in the mineral content of the two different drying method except in sodium, Potassium and Phosphorus of the drying method. This result indicates that the two drying methods have effects on the nutritional quality of catfish.
    Description: Includes: 2 tables and 1 figure.;Also includes: 7 references.
    Keywords: Fisheries ; Clarias gariepinus ; Nigeria ; Port Harcourt ; Smoking ; Production ; Preservative research ; Quality ; freshwater environment ; Processing fishery products ; Freshwater fish ; Proteins ; Vitamins ; Minerals ; Cured products ; Quality assurance ; Aquaculture equipment ; Nutritive value ; Drying ; Methodology ; Comparative studies
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  • 20
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24189 | 19325 | 2018-05-16 14:59:40 | 24189 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: The objective of this study was to determine the quality deterioration of African catfish Clarias gariepinus and Tilapia, Orechromis niloticus stored at-4~'C for 8 weeks. Weekly analysis was conducted to measure protein, moisture, crude fat and ash content and evaluation of the sensory quality. The result clearly reveals that during storage, both the samples showed a highly significant (p〈0.05) decreasing trend in protein, lipid, ash and moisture content. The result shows that protein, moisture, fat and ash content of the fish samples decreases with increasing duration of frozen storage. The fresh samples has the highest value of protein, moisture, fat and ash content while the least value was recorded on the 8th week. 19.98 ~c 2.66%, 80.71 ~c 1.65%, 3.92 ~c 0.5% and 2.52 ~c were recorded for freshly prepared Clarias gariepinus respectively while 12.62 ~c 1.22%, 66.86 ~c 0.68%, 1.08 ~c 1.04% and 1.14 ~c 0.33% were recorded on the 8th week respectively. 20.80 ~c 1.46, 60.75 ~c 2.50, 9.75 ~c 2.50% and 5.85 ~c 2.51% were recorded for freshly prepared Oreochromis niloticus respectively while 25.05 ~c 2.20%, 47.60 ~c 2. 15%, 7.1 ~c 0.20 and 3.00 ~c 2.10% were recorded on the 8th week respectively. After 8 weeks, the total decrease was 7.36%, 13.85%, 2.84% and 1.38% respectively for Clarias gariepinus and 3.75%, 13.45%, 2.65% and 2.85% respectively for Oreochromis niloticus. Sensory evaluation of the fish samples revealed that quality, texture, colour, odour, aroma and taste decrease with increasing duration of storage and best quality obtained when freshly prepared.
    Description: Includes: 4 tables.;Also includes: 11 references
    Keywords: Fisheries ; Clarias gariepinus ; Oreochromis niloticus ; Nigeria ; Owo ; Frozen ; Fish ; Quality ; Sensory ; Evaluation ; Processing ; freshwater environment ; Chemical composition ; Freshwater fish ; Receptors ; Deterioration ; Quality assurance ; Fish storage ; Freezing storage ; Nutritive value ; Microorganisms ; Enzymatic activity ; Processing fishery products ; Storage effects ; Organoleptic properties ; Temperature effects
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  • 21
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24198 | 19325 | 2018-05-16 15:18:03 | 24198 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Energy is one of the main concerns for the future development of any nation. It is by far the largest merchandise in the world and an enormous amount of it is extracted, distributed, converted and consumed in our global society daily .One major problem regarding agricultural produce is related to the product storage in the harvesting season, and identifying an alternative to marketing fresh produce. A useful option is to prevent wastage of produce by drying, using solar energy. In this regard, solar dryer for domestic as welI as industrial usage could be an effective alternative of saving conventional energy. Utilization of solar thermal energy through solar dryer is relatively in a nascent state in our country. This paper gives a description of the efforts made under several researches to design and develop some types of solar dryers.
    Description: Includes: 23 references.
    Keywords: Fisheries ; Environment ; Nigeria ; Makurdi ; Solar drying ; Dryres ; Drying methods ; Drying system ; Solar dryer ; freshwater environment ; Drying ; Fishery products ; Energy ; Processing fishery products ; Utilization ; Storage ; Aquaculture equipment ; Conservation
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  • 22
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24638 | 19325 | 2018-05-24 09:36:38 | 24638 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Study of some Physico-chemical parameters and fish species composition of Doma Darn was carried out between the month of August 2012. Fishing communities along the dam were selected at sampling stations and collection of fish species. The values of physico-parameters obtained for stations were in the range of 28.10-92 m for depth, 27.70-28.48~'for temperature, 7.03-7.64 for PH, 7.23-7.64mg/l for dissolved oxygen (DO), 30.08-31.75 ntu for turbidity, 94.64-105.17mg/l for alkalinity and 79.17-80.58mg/l for total hardness. The result indicated that there was significant difference (p〈0.5)for depth, temperature turbidity and alkalinity, while there was no significant difference (p〈0.05) for DO, pH and water hardness among the stations. The result of these parameters among the duration shows that there was significant different (p〈0.05) in all the parameters except pH. The study revealed that there were twenty-five (25) fish species belonging to 12 families in the dam. The family Cichlidae and Mochokidae and Bagridae which has three each, While the family, Polypteridae, Channidae, Centropomidae, flepsetidae and Protopteridae has the lowest number of one (1) each. The overall result revealed that the Phvsico-chemical parameters were mostly influenced by duration and not much by stations; and parametersoaram measured were within the recommended water quality requirement for growth and survival of aquatic organisms.
    Description: Includes: 10 references.
    Keywords: Chemistry ; Fisheries ; Nigeria ; Doma Dam ; Doma Dam ; Fishing community ; Physico-chemical parameter ; Fish species ; freshwater environment ; automation
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  • 23
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24194 | 19325 | 2018-05-16 15:09:49 | 24194 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: This study was carried out in order to assess the use of solar tent dryer in some selected fishing settlement (Yobe, Daban Masara, Tumbun Beriberi and fish Dam) in Kukawa Local Government. Secondary and Primary data were used in this research. Secondary data were obtained from various literatues while primary data were obtained through the use of structured questionnaires. A total number of 60 respondents were randomly selected and interviewed: Fifteen from each settlement (fish processors). Simple percentages were used in analyzing the data. Findings revealed that, majority of the respondents (fish processors) 80% were not aware of the existence of solar tent dryer that can be used for drying fish, only 20% were aware of solar tent dryer.Among these respondents who are aware of solar tent dryer, only 3.33% have used it. The general perceptions of the respondents believe that they will use it if they are provided with the solar tent dryer. The level of awareness on the use of solar tent dryer for fish processing is very low, there is need for intensive awareness creation, through fishery extension workers.
    Description: Includes: 5 tables.;Also includes: 6 references.
    Keywords: Fisheries ; Nigeria ; Kukawa ; Solar Tent Dryer ; freshwater environment ; Fishery products ; Processing fishery products ; Drying ; Cured products ; Aquaculture equipment ; Artisanal fishing ; Solar power
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  • 24
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 545-545 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 25
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    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 6 (1992) 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 26
    ISSN: 0886-9383
    Keywords: Derivatization reaction ; Factorial design ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of nucleophiles have been successfully identified and quantified using the Kröhnke reaction with 2,3-diphenyl derivatives of quinolizinium salts. Optimization of the reaction conditions by means of a mathematical model involving analysis of the response surface has led to a better understanding of the factors exerting an influence on the above reaction.The parameters chosen were temperature, reaction time, base concentration, water concentration and nucleophile concentration. The reaction was developed in polar aprotic solvents (acetone, acetonitrile). To facilitate the nucleophilic attack, the presence of an organic base (triethylamine) was necessary, although concentrations in excess of 0·15M did not alter the development of the reaction. Since pharmaceutical solutions are often aqueous, the influence of water on the reaction was studied. Low water volumes have no significant influence on the opening of the quinolizinium ring by the nucleophilic reagent. However, when the water proportion exceeded that of the organic solvent, the fluorescence intensity was lower than expected. Development of the fluorescent reaction product was first detected 5 min after the reaction started. The fluorescence intensity reached its optimum value after 138 min.
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  • 27
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 6 (1992), S. i 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 28
    Electronic Resource
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    Journal of Chemometrics 6 (1992), S. 65-83 
    ISSN: 0886-9383
    Keywords: Trilinear decomposition ; Receptor modeling ; Source identification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In many cases, monitoring data for ambient airborne particles can be organized in the form of a three-way data table with one way for chemical species, one for sampling periods and one for sites. A direct trilinear decomposition followed by a matrix reconstruction (DTDMR) is developed to analyze such a data table as a whole. The three-way data set is composed into three two-way matrices by a direct trilinear decomposition (DTD). The column vectors of each of the matrices are called ‘source profiles’, ‘emission patterns’ and ‘site coefficients’ respectively. Particulate sources are identified by examining both their source profiles and emission patterns. After the sources have been identified, emission patterns and site coefficients are used to produce a three-way matrix that gives estimates of mass contributions of sources to the samples collected at every site in every period. By simulation study, not only has the method been verified, but a good indicator has been found that shows the number of factors (i.e. sources) in the system. Unlike other receptor models, DTDMR does not require source profile data and does not involve trial-and-error procedures. Since DTDMR identifies sources based on variations in two dimensions, it has a higher potential to distinguish two sources that have similar chemical compositions. The DTDMR model has provided excellent results with simulated data and has been applied in a real world three-way data set.
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  • 29
    Electronic Resource
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    Journal of Chemometrics 6 (1992), S. 163-175 
    ISSN: 0886-9383
    Keywords: Multiple-correspondence analysis ; Starch granule description ; Image analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Raw starch is composed botanically of characteristic granules of various sizes and shapes, so that each kind of starch may be characterized by the population of its granules. In the present study ten commercial starch species were studied: wheat, rice, manioc, potato, arrowroot, amylomaize, normal maize, waxy maize and two different banana species. Six variables measuring the size and shape of granules were obtained by image analysis. The objective was to find a method to describe and compare the granule populations of the ten species. For such a study, multiple-correspondence analysis (MCA) was applied. MCA makes it possible to draw similarity maps of categories and objects. For each starch species the frequency distributions (histograms) of the six variables were assessed and each granule was characterized by its species and the classes of histograms to which it belonged. MCA was applied to the granule table and a description of the histogram classes and the granules was obtained. From the variables description a general typology of the granules was deduced. The similarity maps showed considerable scatter of the granules for all species except rice. A particular species could therefore not be identified by a single granule, but the granule distribution seemed to be characteristic. MCA was an appropriate method to analyse these data because it points out non-linear relationships between quantitative and qualitative variables.
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  • 30
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    Journal of Chemometrics 6 (1992), S. 177-188 
    ISSN: 0886-9383
    Keywords: PLS ; Prediction error ; Background constituents ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modification of a technique proposed by Lorber and Kowalski for the estimation of prediction errors is presented. The method is applied to five data sets. The results show that for some data sets the estimated prediction errors are close to the actual prediction errors for samples within the calibration range, while samples outside the calibration range must be background corrected before quantification of the prediction error.
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  • 31
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    Journal of Chemometrics 6 (1992), S. 199-216 
    ISSN: 0886-9383
    Keywords: MARS ; Splines ; Multivariate calibration ; Non-linear ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This tutorial paper presents a simplified view of one of the more recently published multivariate calibration methods particularly suited to dealing with non-linear data sets. The method is referred to as MARS and stands for multivariate adaptive regression splines. Simple examples are provided to explain the workings of the method.
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  • 32
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    Journal of Chemometrics 4 (1990), S. 47-50 
    ISSN: 0886-9383
    Keywords: Classification ; Pattern recognition ; Preprocessing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Over the past 15 years the linear learning machine has been applied to a large number of chemical problems. The learning machine approach is conceptually simple and does not require knowledge about the statistical distribution of the data. However, there are problems associated with this approach. One problem which has not been investigated is the influence of mislabeled samples on the positioning of the hyperplane in feature space. If a few samples in a data set are incorrectly tagged prior to training (i.e. the samples are labeled as members of class 2 even though they are actually members of class 1), it is still possible using the linear learning machine to achieve a classification success rate of 100% for the training set. However, unfavorable results will be obtained for the prediction set. The magnitude of this effect and its potential implications regarding the proper use of the linear learning machine are discussed.
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  • 33
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    Journal of Chemometrics 4 (1990), S. 51-59 
    ISSN: 0886-9383
    Keywords: Deconvolution ; Jansson's method ; Peak restoration ; Iterative deconvolution ; Peak resolution ; Non-linear deconvolution ; Super-resolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In previous papers Jansson's method was found to be successful at deconvolving severely overlapped gas chromatographic peaks. In the most recent paper the method was evaluated with respect to quantitative accuracy, peak area and retention time repeatability. The problems associated with deconvolving noisy data and some alternatives which can improve the ability of Jansson's method to deconvolve noisy data are discussed. These alternatives include presmoothing the data with a nine-point, third-order polynomial filter and data reblurring. This paper will test these methods on peaks with various degrees of resolution and signal-to-noise ratios.
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  • 34
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    Journal of Chemometrics 4 (1990), S. 61-77 
    ISSN: 0886-9383
    Keywords: Infrared ; Spectroscopy ; Spectrometry ; Retrieval ; Confirmation ; Chemometrics ; Adequate peaks ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the series of analytical techniques for identification of chemical substances, infrared spectrometry presents by far the highest information content. However, the information is most complicated too. It concerns a multitude of band positions, band intensities and band shapes, which, moreover, can be disturbed by matrix and other effects. The high redundancy, however, allows conclusions to be made by a qualitative, subjective procedure.IR is often used to prove the equality between a sample and a reference material, e.g. in quality control of a production process. In forensic control, the question to be answered is mostly not to prove equality, but whether or not the presence of a compound in a sample, e.g. a drug, can be proved. Moreover, testing has to be performed according to objective rules.To fulfil these requirements, a new retrieval algorithm, the ‘Adequate Peaks Search’, is presented. It concerns representing the reference spectra by sets of adequate peak positions and the sample spectrum by a set of all peak positions, whereafter the cross-sections of the sample set and the reference sets are determined. The concept ‘adequate peak’ is defined and criteria have been formulated to evaluate the results into a positive (presence of the analyte is proved) or negative (presence is not proved) conclusion.The detection limit when the Adequate Peaks Search (APS) method was applied was four to seven times lower than that attained by a number of experts.
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  • 35
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    Journal of Chemometrics 4 (1990), S. 79-90 
    ISSN: 0886-9383
    Keywords: PLS ; Three-way matrices ; Calibration ; Residual bilinearization ; Background correction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When using hyphenated methods in analytical chemistry, the data obtained for each sample are given as a matrix. When a regression equation is set up between an unknown sample (a matrix) and a calibration set (a stack of matrices), the residual is a matrix R.The regression equation is usually solved by minimizing the sum of squares of R. If the sample contains some constituent not calibrated for, this approach is not valid. In this paper an algorithm is presented which partitions R into one matrix of low rank corresponding to the unknown constituents, and one random noise matrix to which the least squares restrictions are applied. Properties and possible applications of the algorithm are also discussed.In Part 2 of this work an example from HPLC with diode array detection is presented and the results are compared with generalized rank annihilation factor analysis (GRAFA).
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  • 36
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    Journal of Chemometrics 4 (1990), S. 91-96 
    ISSN: 0886-9383
    Keywords: Sample size ; Monte Carlo ; Multivariate, normal ; Q-Q plots ; Classification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Because many pattern recognition techniques are predicated on the assumption of mutivariate normal data, Monte Carlo simulation studies were performed to determine the number of samples that are necessary to describe a multivariate normal population adequately. From these studies we have learned that hundreds of samples are required. These results suggest that parametric procedures should only be used to analyze very large data sets.
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  • 37
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    Journal of Chemometrics 4 (1990), S. 97-100 
    ISSN: 0886-9383
    Keywords: Matrix decomposition ; NIPALS ; Principal component ; SIMCA ; PLS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Non-linear Iterative Partial Least Squares (NIPALS) algorithm is used in principal component analysis to decompose a data matrix into score vectors and eigenvectors (loading vectors) plus a residual matrix. NIPALS starts with some guessed starting vector. The principal components obtained by NIPALS depends on the starting vector; the first principal component could not always be computed. Wold has suggested a starting vector for NIPALS, but we have found that even if this starting vector is used, the first principal component cannot be obtained in all cases. The reason why such a situation occurs is explained by the power method. A simple modification of the original NIPALS procedure to avoid getting smaller eigenvalues is presented.
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    Journal of Chemometrics 4 (1990), S. 101-101 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 4 (1990), S. 102-102 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 40
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 4 (1990) 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 4 (1990), S. 102-102 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 42
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    Journal of Chemometrics 4 (1990), S. i 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 4 (1990), S. 103-121 
    ISSN: 0886-9383
    Keywords: Kalman filter ; Recursive digital filter ; Square-root filter ; Information filter ; Parameter estimation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of recursive filtering techniques for parameter estimation in a variety of areas is reviewed. In particular, the Kalman filter algorithm is described, along with several variations, including square-root, UDUT and information filters. The solution to parameter estimation problems is discussed for both linear and non-linear models. Applications described include calibration, curve resolution in spectroscopy, chromatography, electrochemistry, kinetic analysis and process monitoring.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 45
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    Journal of Chemometrics 7 (1993), S. 243-253 
    ISSN: 0886-9383
    Keywords: Orthogonal expansion ; Mapping ; Modelling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we discuss the orthogonal expansion of data matrices and its application to mapping and modelling. Two new methods, modified optimal discriminant plane (MODP) for mapping and order Gram-Schmidt orthogonalization (OGSO) for modelling, are proposed and examples are given.
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    Journal of Chemometrics 7 (1993) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 47
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    Journal of Chemometrics 7 (1993), S. 381-392 
    ISSN: 0886-9383
    Keywords: Factor analysis ; Kolmogorov-Smirnov test ; Non-parametric tests in factor analysis ; Non-parametric test for principal components ; Principal component analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Each eigenvector of the dispersion matrix [X]T [X] was shown to be a partial predictor of the original data matrix [X], the sum of the predictions from the individual principal components being equal to the expectance of [X]. By comparing the distributions of the members of two neighbouring predicted matrices, [X̃]1…i and [X̃]1…i+1 (i.e. the sums of the first i and i + 1 individual predictions respectively), it was shown that they should be indistinguishable provided that i is equal to or greater than the effective rank of [X], and significantly different otherwise. This was confirmed by analysing the visible absorption spectra of methyl orange and methyl red solutions as well as the Raman spectra of Na2SO4 and MgSO4 solutions. On the grounds of these findings, a non-parametric goodness-of-fit test for assessing the effective rank of [X] was proposed which proved to be comparatively conservative and more robust than most currently used tests.
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    Journal of Chemometrics 7 (1993), S. 447-452 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 7 (1993), S. 477-494 
    ISSN: 0886-9383
    Keywords: Three-way principal components analysis ; Core matrix ; Body diagonalization ; Lower and upper bounds ; Simulation ; Soil contamination ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contrast with conventional PCA, a direct superposition and joint interpretation of loading plots is not possible in three-way PCA, since there may be data variance which is described by unequal components of different modes. The contributions to variance of all possible combinations of components are described in the core matrix. Body diagonalization, which is achieved by appropriate rotation of component matrices, is an essential tool for simplifying the core matrix structure. The maximum degree of body diagonality which may be obtained from such transformations is analysed from both the mathematical and simulation viewpoints. It is shown that, at least in the average case, high degrees can be expected, which makes the procedure reasonable for many practical applications. Furthermore, simulation as well as theoretical derivation show that the success of body diagonality depends on the so-called polarity of the core array. The methodology is illustrated by a three-way data example from environmental chemistry.
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    Journal of Chemometrics 7 (1993) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 51
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    Journal of Chemometrics 7 (1993), S. 495-526 
    ISSN: 0886-9383
    Keywords: Standard errors ; Eigenvalues ; PCA ; MLR ; GRAM ; Rank estimation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New expressions are derived for the standard errors in the eigenvalues of a cross-product matrix by the method of error propagation. Cross-product matrices frequently arise in multivariate data analysis, especially in principal component analysis (PCA). The derived standard errors account for the variability in the data as a result of measurement noise and are therefore essentially different from the standard errors developed in multivariate statistics. Those standard errors were derived in order to account for the finite number of observations on a fixed number of variables, the so-called sampling error. They can be used for making inferences about the population eigenvalues. Making inferences about the population eigenvalues is often not the purposes of PCA in physical sciences. This is particularly true if the measurements are performed on an analytical instrument that produces two-dimensional arrays for one chemical sample: the rows and columns of such a data matrix cannot be identified with observations on variables at all. However, PCA can still be used as a general data reduction technique, but now the effect of measurement noise on the standard errors in the eigenvalues has to be considered. The consequences for significance testing of the eigenvalues as well as the usefulness for error estimates for scores and loadings of PCA, multiple linear regression (MLR) and the generalized rank annihilation method (GRAM) are discussed. The adequacy of the derived expressions is tested by Monte Carlo simulations.
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    Journal of Chemometrics 7 (1993), S. 559-566 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 8 (1994), S. 21-36 
    ISSN: 0886-9383
    Keywords: GRAM ; Tucker ; Unfold ; NBRA ; Second-order ; Three-way ; PARAFAC ; Trilinear ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: If an analytical instrument or instrumental method gives a response matrix when analyzing a pure analyte, the instrument or instrumental method is called a second-order method. Second-order methods that generate a response matrix for a pure analyte of rank one are called rank-one second-order methods. If the response matrix of a pure analyte is not rank one, essentially two cases exist: medium rank (between two and five) and high rank (greater than five). Subsequently, medium- and high-rank second-order calibration tries to use medium- and high-rank second-order methods to analyze for analytes of interest in a mixture. A particular advantage of second-order methods is the ability to analyze for analytes of interest in a mixture which contains unknown interferences. Keeping this advantage is the challenge on moving away from rank-one second-order calibration methods. In this paper a medium-rank second-order calibration method is proposed based on least-squares restricted Tucker models. With this method the second-order advantage is retained.
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    Journal of Chemometrics 8 (1994), S. 81-93 
    ISSN: 0886-9383
    Keywords: Sensory evaluation ; Cumulative ranks ; Assessor variation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A graphical method of assessing differences between sets of rankings based on cumulative ranks is developed. The method can be used to identify rankings that differ over all or just part of the range of objects ranked. The method is applied to an example of sensory evaluation of green peas in which ten assessors scored six attributes on each of 60 samples.
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    Journal of Chemometrics 8 (1994), S. i 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 56
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    Journal of Chemometrics 8 (1994), S. 155-168 
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    Keywords: Trilinear models ; Tensorial resolution ; PARAFAC ; Swamps ; Two-factor degeneracy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The alternating least squares PARAFAC algorithm is a useful tool for resolving trilinear three-way data arrays. Occasionally, however, it becomes bogged down for many iterations in the vicinity of a poor quality resolution before moving on to a much superior optimum fit. We investigate this behavior in a simulation study and suggest ways of overcoming the obstacles it presents.
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Journal of Chemometrics 8 (1994), S. i 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Journal of Chemometrics 8 (1994), S. 181-203 
    ISSN: 0886-9383
    Keywords: RAFA ; GRAM ; Eigenvalues ; Bias ; Variance ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rank annihilation factor analysis (RAFA) is a method for multicomponent calibration using two data matrices simultaneously, one for the unknown and one for the calibration sample. In its most general form, the generalized rank annihilation method (GRAM), an eigenvalue problem has to be solved. In this second paper expressions are derived for predicting the bias and variance in the eigenvalues of GRAM. These expressions are built on the analogies between a reformulation of the eigenvalue problem and the prediction equations of univariate and multivariate calibration. The error analysis will also be performed for Lorber's formulation of RAFA. It will be demonstrated that, depending on the size of the eigenvalue, large differences in performance must be expected. A bias correction technique is proposed that effectively eliminates the bias if the error in the bias estimate is not too large. The derived expressions are evaluated by Monte Carlo simulations. It is shown that the predictions are satisfactory up to the limit of detection. The results are not sensitive to an incorrect choice of the dimension of the factor space.
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    Journal of Chemometrics 4 (1990), S. i 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Journal of Chemometrics 4 (1990), S. 337-354 
    ISSN: 0886-9383
    Keywords: Chemometrics ; Chemometrics Society ; History of chemometrics ; Pioneers of modern chemometrics ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This is a first foray into the historical start and early years of chemometrics from about 1972 onwards. We have gathered interviews with three originators (Kowalski, Wold and Massart) as well as with a selected group of six other well-known chemometricians who gradually became active in the 1970s (Christie, Clementi, Hopke, Martens, Brown and Deming). The interviews include amongst a host of subjective recollections a succinct record of the key historical literature as highlighted by the interviewees' own rankings of ‘earliest’ and ‘best’.A discussion of the most general commonalities in these interviews together with other historical material is presented in the second part of the paper.
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    Journal of Chemometrics 4 (1990), S. 355-360 
    ISSN: 0886-9383
    Keywords: Pattern recognition ; U.K. chemometrics usage ; Quantitative structure-activity relationships ; Artificial intelligence ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A survey of members of the U.K. QSAR Discussion Group has been made to determine the extent of use and development of chemometric and artificial intelligence (AI) methods in the analysis of multivariate quantitative structure-activity relationship (QSAR) data in the U.K. Chemometric methods were found to be well established in both industrial and educational establishments and there was significant method development occurring. AI methods were not employed to any great extent and the general level of interest in these techniques was low compared to chemometric methods. A requirement for more education in multivariate statistical methods and regression methods was indicated. A need for a user-friendly, comprehensive, commercially available multivariate statistical package containing multivariate stability testing and regression diagnostic methods was identified.
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    Journal of Chemometrics 4 (1990), S. 361-377 
    ISSN: 0886-9383
    Keywords: Abstract factor analysis ; Exploratory data analysis ; Principal components ; Simulated equilibria ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract factor analyses were performed on databases consisting of simulated samples from aqueous equilbria. The program COMPLEX was used to generate equilibrium species in a system of three reactant metals and five reactant bases. Reactant concentrations and pH were drawn from random-normal distributions so that sample data vectors comprised a multivariate log-normal distribution of equilibrium concentrations. In addition, sample groups were created containing different distributions for pH and reactant concentrations.Equilibrium species were shown to contain variance contributed by change in pH among samples as well as change in reactant concentrations. Factor modelling revealed the qualitative relationships among the species and how the relationships change with pH. Factors also revealed those reactants containing variance in the data matrix. In some cases, reactant variance obscured relationships between pH and the equilibrium species.Since factor modelling of a simulated data matrix revealed the expected chemical equilibrium interactions, a potentially powerful tool exists for investigating the effects of outliers and error.
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    Journal of Chemometrics 8 (1994), S. 301-302 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 8 (1994) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Journal of Chemometrics 8 (1994), S. 305-331 
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    Keywords: Pyrolysis ; Mass spectroscopy ; Multivariate analysis ; Biological material identification ; Convexity ; Cones ; Subspaces ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This work addresses the classification of high-dimensional time-dependent pyrolysis mass spectra of biological samples. The aim was the detection and classification of biological agents, and the developed approach resembles mixture analysis. The data were projected on to a low-dimensional subspace using singular value decomposition. Then a convex cone was formed on this subspace, showing as its corners physically meaningful components of the sample. This technique enabled separation of a biological material signal largely independent of the absolute amount of sample. The detection of the presence of any biological material could be accomplished based on the convex cone alone, without other reference to the mass spectra. Automated clustering of samples was successfully carried out using a minimal spanning tree.
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    Journal of Chemometrics 8 (1994), S. 373-373 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Journal of Chemometrics 4 (1990), S. 389-412 
    ISSN: 0886-9383
    Keywords: Chemometrics ; Chemometrics Society ; History of chemometrics ; Pioneers of modern chemometrics ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This is a first foray into the historical start and early years of chemometrics from about 1972 onwards. We have gathered interviews with three originators (Kowalski, Wold and Massart) as well as with a selected group of six other well-known chemometricians who gradually became active in the 1970s (Christie, Clementi, Hopke, Martens, Brown and Deming). The interviews include amongst a host of subjective recollections a succinct record of the key historical literature as highlighted by the interviewees' own rankings of ‘earliest’ and ‘best’.A discussion of the most general commonalities in these interviews together with other historical material is presented in the second part of the paper.
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    Keywords: Discriminant analysis ; Size-exclusion chromatography ; Wheat proteins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Continuous digitalized signals such as spectra, electrophoregrams or chromatograms generally have a large number of data points and contain redundant information. It is therefore troublesome performing discriminant analysis without any preliminary selection of variables. A procedure for the application of canonical discriminant analysis (CDA) on this kind of data is studied. CDA can be presented as a succession of two principal component analyses (PCAs). The first is performed directly on the raw data and gives PC scores. The second is applied on the gravity centres of each qualitative group assessed on the normalized PC scores. A stepwise procedure for selection of the relevant PC scores is presented. The method has been tested on an illustrative collection of 165 size-exclusion high-performance (SE-HPLC) chromatograms of proteins of wheat belonging to 55 genotypes and grown in three locations. The discrimination of the growing locations was performed using seven to nine PC scores and gave more than 86% accurate classifications of the samples both in the training sets and the verification sets. The genotypes were also rather well identified, with more than 85% of the samples correctly classified. The studied method gives a way of assessing relevant mathematical distances between digitalized signals according to qualitative knowledge of the samples.
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    Keywords: Principal components ; Multiple and stepwise regression ; Non-parametric density and regression estimation ; Bootstrap inference ; Canonical correlation ; PLS regression ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A statistical study of the dependence between various critical fusion temperatures of a certain kind of coal and its chemical components is carried out. As well as using classical dependence techniques (multiple, stepwise and PLS regression, principal components, canonical correlation, etc.) together with the corresponding inference on the parameters of interest, non-parametric regression and bootstrap inference are also performed.
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    Journal of Chemometrics 9 (1995), S. 197-209 
    ISSN: 0886-9383
    Keywords: proficiency test ; true value ; homogeneity robust statistic ; standard ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Profficiency tests raise two types of problems: (i) the homogeneity of a sample must be carefully checked before using it as a reference material; (ii) it is necessary to define a conventional reference value (RV) in order to rank participants. Since these topics are poorly addressed in the literature, a reference material was specially prepared in order to propose a procedure for verifying homogeneity and to establish whether the algorithms classically used to compute the conventional true value have an influence on the conclusion of the test.The homogeneity of the sample was not perfect and univariate and multivariate techniques were used to demonstrate some analytes can be suspected as heterogeneous. However, this was considered adequate for introducing the sample in a large proficiency test organized between four laboratory associations which regularly perform such tests. Altogether more than 3000 measurements were collected and eight algorithms were applied to compute the RV on 14 analytes. Thus is was possible to demonstrate that some of these algorithms are better adapted than others. It is also obvious that some analytes are better suited to proficiency testing.It can be concluded from this work that some effort towards standardization would be profitable to check homogeneity or to compute the RV, especially since the economic weight of proficiency testing is becoming even more important with the development of certification accreditation.
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    Journal of Chemometrics 5 (1991), S. 129-145 
    ISSN: 0886-9383
    Keywords: Multivariate calibration ; Biased regression ; Partial least squares (PLS) ; Principal component regression (PCR) ; Model validation ; Non-linear calibration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: With the goal of understanding global chemical processes, environmental chemists have some of the most complex sample analysis problems. Multivariate calibration is a tool that can be applied successfully in many situations where traditional univariate analyses cannot. The purpose of this paper is to review multivariate calibration, with an emphasis being placed on the developments in recent years. The inverse and classical models are discussed briefly, with the main emphasis on the biased calibration methods. Principal component regression (PCR) and partial least squares (PLS) are discussed, along with methods for quantitative and qualitative validation of the calibration models. Non-linear PCR, non-linear PLS and locally weighted regression are presented as calibration methods for non-linear data. Finally, calibration techniques using a matrix of data per sample (second-order calibration) are discussed briefly.
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    Journal of Chemometrics 5 (1991), S. 147-161 
    ISSN: 0886-9383
    Keywords: Digital filtering ; Real-time analysis ; Kalman filtering ; Infrared spectroscopy ; Principal components regression ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Real-time monitoring of pollutant levels from a mobile measuring platform requires fast, flexible data analysis methods. This paper reports a method for rapid analysis of passive remotely sensed infrared data with the aid of a Kalman filter. The background spectra produced by emission from the atmosphere are modelled at the start of the data collection sequence with a simple principal components model obtained by eigenanalysis of the initial ‘blank’ data taken with the spectrometer. The species of interest are included in the state space model by a separate measurement of their infrared spectra. It is demonstrated that for best filter performance in detecting the simulated pollutant species SF6 in the atmosphere, a filter model with two principal components describing the emission background works best. The filter ‘maps’ of SF6 closely follow the integrated spectral intensities measured after removal of suitable backgrounds.
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    Journal of Chemometrics 5 (1991), S. 163-179 
    ISSN: 0886-9383
    Keywords: Principal component analysis ; Factor analysis ; Chemometrics ; Exploratory data analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Principal component analysis is used to examine large multivariate databases. The graphical approach to exploratory data analysis is described and illustrated with a single example of chemical composition data obtained on environmental dust particles. While the graphical approach to exploratory data analysis has certain advantages over the numerical procedures, the empirical approach described here should be viewed as complementary to the more robust treatments that statistical methodologies afford.
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    Journal of Chemometrics 5 (1991), S. 181-192 
    ISSN: 0886-9383
    Keywords: Chemometrics ; Systems theory ; Experimental design ; Multivariate analysis ; Measurement science ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemometrics is defined as the application of mathematical and statistical methods to chemical systems. Systems theory is seen to be useful for organizing and categorizing the inputs to and outputs from chemical systems. Advances in measurement science in the 1950s and 1960s, particularly in analytical chemistry, created a need for a multivariate approach to data analysis. Early chemometrics emphasized the use of structure-finding methods for existing data sets. In many instances, data sets can be obtained from designed experiments. Such data sets are more likely to contain the desired information and the data can usually be acquired at less cost. Renewed interest in statistical process control will provide many new, more robust data sets in the future.
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    Journal of Chemometrics 5 (1991), S. 193-199 
    ISSN: 0886-9383
    Keywords: Kalman filter ; Chemometrics ; 5-Br-PADAP ; Metallic ions ; Simultaneous spectrophotometric determination ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes the simultaneous determination of cobalt, nickel, copper, zinc and cadmium by spectrophotometry and the Kalman filter method. Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) react with 5-bromo-2-(2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of cationic surfactant cetyl pyridinium bromide (CPB) to form five different coloured ternary complexes. The absorption curves of these complexes overlap severely in the scanning range 500-620 nm. The Kalman filter algorithm is successfully applied to resolve the overlapped absorption curves and therefore makes the simultaneous determination of these metallic ions possible without tedious pretreatment. The proposed method is applied to analyse the titled elements in synthetic samples and in environmental samples such as hair, fingernail and river water samples with satisfactory results.
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  • 77
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    Journal of Chemometrics 5 (1991), S. 201-209 
    ISSN: 0886-9383
    Keywords: Uncertainty ; Step function ; Additive model ; Transformation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An additive model is used to express the observed value of a sample characteristic as the sum of the true sample characteristic and a value of the data collection error, commonly known as experimental error. The data uncertainty of the experimental results (or of a survey data set) is defined as the expected squared error. The expected squarred error may change with the sample characteristic, e.g. the error moment could be concentration-dependent. The relationship between the error variance and the analyte concentration may not be very distinct. In such a case the data transformation to stabilize the error moments may not be appropriate. A step function is proposed as an alternative way to represent the second moment of the error. The data uncertainty is defined as the weighted average of the step values of the second raw moment of the error, using the appropriate proportions of the routine samples as weights. The data uncertainties associated with the different data collection stages were evaluated by using regional soil survey data.
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  • 78
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    Journal of Chemometrics 5 (1991), S. 211-225 
    ISSN: 0886-9383
    Keywords: Shot noise ; Expectation-maximization ; Regression ; Deconvolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple algorithm for deconvolution and regression of shot-noise-limited data is illustrated in this paper. The algorithm is easily adapted to almost any model and converges to the global optimum. Multiple-component spectrum regression, spectrum deconvolution and smoothing examples are used to illustrate the algorithm. The algorithm and a method for determining uncertainties in the parameters based on the Fisher information matrix are given and illustrated with three examples. An experimental example of spectrograph grating order compensation of a diode array solar spectroradiometer is given to illustrate the use of this technique in environmental analysis. The major advantages of the EM algorithm are found to be its stability, simplicity, conservation of data magnitude and guaranteed convergence.
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  • 79
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    Journal of Chemometrics 9 (1995) 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 80
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    Journal of Chemometrics 9 (1995), S. 451-457 
    ISSN: 0886-9383
    Keywords: non-linear regression ; optimization ; robust methods ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several robust regression methods, including a new proposal, are described and their properties discussed. Resistance to various types of outliers and non-normality is demonstrated. The techniques are applied to non-linear regression models from chemical kinetics and calibration. Optimization of the types of objective functions encountered when applying robust regression is considered.
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  • 81
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    Journal of Chemometrics 9 (1995), S. 471-481 
    ISSN: 0886-9383
    Keywords: batch prediction ; continuum regression ; multivariate calibration ; sequential prediction ; simultaneous prediction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In analytical chemistry a single fitted calibration model is used repeatedly to predict the level of the analyte of interest for the specimens comprising the prediction set. Unlike the calibration (or training) set, which is often limited in size, the prediction set can be very large.In the case of multivariate calibration a number of methods such as PLS and PCR are commonly used to construct the calibration model. The set of instrumental measurements and the reference analyte level are available for each specimen in the calibration set. For specimens in the prediction set, only the instrumental measurements are available, since the problem is to predict the analyte level for these specimens. It is not widely recognized that predictions of the analyte levels for individual specimens can be improved by utilizing seemingly unrelated information from the instrumental measurements associated with the other members of the prediction set. In the case of PCR there exists a very straightforward procedure for doing this. A description of the various sources of prediction errors is provided to explain the ability of PCR to utilize this additional information. The use of PCR in this context is illustrated with both a synthetic and a real example.
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  • 82
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    Journal of Chemometrics 5 (1991), S. 291-298 
    ISSN: 0886-9383
    Keywords: Absorbance ratio ; Statistical confidence ; Quality control ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ratio measurements are commonly used to address a variety of analytical problems in environmental, forensic and pharmaceutical laboratories. In absorbance ratioing techniques, analytical chemists rely on the spectral features of the analyte(s) of interest. The absorbances at two wavelengths are monitored and the ratio of these two absorbances is computed. This ratio is then used to confirm the identity of the analyte(s) of interest, the purity of a product of the overlap of chromatographic peaks. These decisions often have far-reaching consequences (e.g. the identification of the source, biogenic or petrogenic, of hydrocarbons in biological tissues or water). Given the cost and the liabilities associated with such decisions, it is unfortunate that these ratios are seldom reported with any statistical confidence. The purpose of this study is to delineate the parameters that affect absorbance ratio measurements. The models that can be used to estimate the statistical confidence in these measurements are derived and evaluated experimentally. The results show that these models can estimate the relative standard deviations in absorbance ratios accurately. They can also estimate the effect of signal-to-noise ratio and the choice of wavelengths on the precision of absorbance ratios.
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  • 84
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    Journal of Chemometrics 5 (1991), S. 299-308 
    ISSN: 0886-9383
    Keywords: Errors in variables ; Orthogonal regression ; Latent variables ; Acid rain ; Acidic deposition ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Techniques for testing for and estimating relative bias between two laboratories are developed and applied to a survey of the chemistry of streams in the United States. The design of the quality assurance program allows estimation of linear corrections for bias as well as testing of the hypothesis of linearity. Designs of this type are useful, but improvements are suggested.
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  • 85
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    Journal of Chemometrics 5 (1991), S. 309-319 
    ISSN: 0886-9383
    Keywords: Confidence intervals ; Products of normal random variables ; Risk/exposure modeling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In many environmental applications, such as exposure assessment and risk modelling, the desired estimate is a random variable computed as the product of three independently distributed random variables. These variables may not necessarily have the same mean and variance. The method for finding the 100(1 - α)% confidence interval for the mean of the product random variable has been proposed by some practitioners as the product of the 100(1 - α)% confidence interval of the three means. In this paper we show that the distribution of the product of three independent normal variables is not normal. We find the mean and variance of the product distribution. Further, we show that although the mean of the product is equal to the product of the means, the product of the three confidence intervals is not a good approximation of the confidence intervals for the mean of the product variable. The confidence interval of the mean of the product variable may be estimated by computer simulation. An algorithm for estimating the confidence interval for the mean of the product random variable is given. The program implementing this algorithm is given as an appendix.
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  • 86
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    Journal of Chemometrics 5 (1991), S. 321-331 
    ISSN: 0886-9383
    Keywords: Screening ; Ground-water quality ; Monitoring ; Volatile organic compounds (VOCs) ; Optimization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the presence of 31-35 commonly measured volatile organic compounds (VOCs) in ground water can be detected with small error rates by using screening methods which analyze for a subset of such VOCs. A study of selected data sets indicates that analytical determinations of only from two to eight VOCs will suffice to detect 95% of all VOC hits. It is also shown that a serially optimal algorithm for selecting the VOCs for screening is very nearly as accurate as a globally optimal algorithm and much easier to implement. These conclusions are supported by empirical evidence from two drinking-water data sets and one hazardous waste site data set. Additional research areas are also outlined.
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  • 87
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    Journal of Chemometrics 5 (1991) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 88
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    Journal of Chemometrics 5 (1991), S. i 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 89
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    Journal of Chemometrics 5 (1991), S. 333-343 
    ISSN: 0886-9383
    Keywords: Rank estimation ; Bootstrap resampling ; Canonical correlation ; Excitation-emission matrix ; Singular value decomposition ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rank estimation by canonical correlation analysis in multivariate statistics has been proposed as an alternative approach for estimating the number of components in a multicomponent mixture. A methodological turning point of this new approach is that it focuses on the difference in structure rather than in magnitude in characterizing the difference between the signal and the noise. This structural difference is quantified through the analysis of canonical correlation, which is a well-established data reduction technique in multivariate statistics. Unfortunately, there is a price to be paid for having this structural difference: at least two replicate data matrices are needed to carry out the analysis.In this paper we continue to explore the potential and to extend the scope of the canonical correlation technique. In particular, we propose a bootstrap resampling method which makes it possible to perform the canonical correlation analysis on a single data matrix. Since a robust estimator is introduced to make inference about the rank, the procedure may be applied to a wide range of data without any restriction on the noise distribution. Results from real as well as simulated mixture samples indicate that when used in conjunction with this resampling method, canonical correlation analysis of a single data matrix is equally efficient as of replicate data matrices.
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  • 90
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    Journal of Chemometrics 5 (1991), S. 345-360 
    ISSN: 0886-9383
    Keywords: Three-way PCA ; Three-way PLS ; PARAFAC ; Trilinear ; Unfolding ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the calibration of chromatographic systems, different methods can be used. One class of methods utilizes three-way approaches. The calibration problem is stated in such a way that the decomposition of a three-way array can serve for the prediction of retention on new stationary phases.Two three-way approaches are presented: the Unfold-PCA and PARAFAC models. The theory of both methods is presented and the differences are highlighted, the main difference being that PARAFAC is a trilinear decomposition whereas Unfold-PCA is not. Both three-way methods are evaluated on a small data set consisting of retention measurements of eight solutes at six mobile phase compositions on six stationary phases. The differences in performance of the two models are minor.For calibration purposes, two variants of the methods are discussed: three-way PLS and an extension of PARAFAC. Again the theory and differences between the two methods are explained. The predictive performance of the two methods is compared using the same data set as earlier. The differences in predictive performance, however, are minor. Both methods are capable of predicting 98% of the variation in the test sets. Yet, there are other considerations when comparing methods than predictive performance, e.g. the quality of the predictions.
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  • 91
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    Journal of Chemometrics 5 (1991), S. 361-374 
    ISSN: 0886-9383
    Keywords: Closure ; Normalization ; Multivariate trimming ; Minimum distance ; Bootstrap ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compositional data arise naturally in several branches of science, including chemistry, geology, biology, medicine, ecology and manufacturing design. In chemistry, these constrained data seem to occur typically when raw data are normalized or when output is obtained from a constrained estimation procedure, such as might be used in a source apportionment problem. It is important not only for chemists to be aware that the usual multivariate statistical techniques are not applicable to constrained data, but also to have access to appropriate techniques as they become available. The currently available methodology is due principally to Aitchison and is based on log-normal models. This paper suggests new parametric and non-parametric approaches to significantly improve the existing methodology. In the parametric setting, some recent work of Rayens and Srinivasan is extended and a practical regression model is proposed. In the development of the non-parametric approach, minimum distance methods coupled with multivariate bootstrap techniques are used to obtain point and region estimators.
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  • 92
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    Journal of Chemometrics 5 (1991), S. 375-387 
    ISSN: 0886-9383
    Keywords: Determinant criterion ; Multiresponse non-linear fitting ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This work evaluates objective functions for multiresponse non-linear modeling using computer simulations. Tests are performed under a variety of signal-to-noise ratios and noise variance-covariance structures. The standard error of prediction for the model parameters, computed from 50 trials, is used for performance comparisons. The full rank and rank-deficient problems are considered. For the full rank problem one model was investigated, a first-order two-step consecutive reaction model, and two objective functions were considered, the total sum of squares and the determinant criterion. No distinction could be made between the two objective functions for this model.For the rank-deficient case two models were investigated, a first-order two-step consecutive reaction as in the full rank case, and a pH titration model described by the Henderson-Hasselbalch equation. Three objective functions were investigated for the rank-deficient case, the total sum of squares, a weighted total sum of squares and the determinant criterion. The total sum of squares was found to perform poorly under all conditions tested compared to the weighted total sum of squares and the determinant criterion. The determinant criterion was found to perform much better than the other two criteria when the data have a combination of a low signal-to-noise ratio and high variance-covariance noise structure.
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  • 93
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    Journal of Chemometrics 5 (1991), S. 405-409 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 94
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    Journal of Chemometrics 5 (1991), S. 389-403 
    ISSN: 0886-9383
    Keywords: Acoustic emission ; Pattern recognition ; Feature selection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Features used to characterize acoustic emission signals from chemical systems are evaluated with regard to their potential for pattern recognition. Eight chemical systems involving phase transitions, hydration, dissolution and effervescence are employed and treated as separate signal classes. These are compared pairwise and the discriminatory capabilities of about 50 features are investigated by computing Fisher weights. Time domain and frequency domain descriptors are examined. Correlations among the features evaluated are also reported. Recommended descriptors are the mean and median frequencies, frequency bandwidth, number of level crossings (0% and 25%), crest factor (time and frequency domains), half-life, kurtosis and normalized percentiles of the signal and its power spectrum. The effectiveness of the recommended descriptors is demonstrated through the separation of signal classes in two different systems (melting ice and an enzyme-catalyzed gas formation reaction) by principal components analysis.
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  • 95
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 96
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 97
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    Journal of Chemometrics 5 (1991), S. 416-416 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 98
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    Journal of Chemometrics 5 (1991) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 99
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    Journal of Chemometrics 5 (1991), S. i 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 100
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    Journal of Chemometrics 5 (1991), S. 417-434 
    ISSN: 0886-9383
    Keywords: Factor analysis ; Power density distribution ; Chromatography ; Absorption spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Evaluation of the results of factor analysis of sets of spectroscopically detected chromatograms is carried out by examining the shapes of the abstract factors. This is done either by visual inspection or by analysis of the power density spectra produced from them. Owing to constraints imposed by the column function and the spectroscopic instrument function, the information content of the chromatograms necessarily occurs at low spatial frequencies. As a consequence, it appears as relatively broad features in the abstract chromatograms and as a peak in the low-frequency region of the corresponding power density plot. On the basis of examination of the power density distribution, a well-defined distinction is made between primary and secondary abstract factors. The major uncertainty encountered in determining the number of chemical components appears to arise from effects of contaminants in reagents.
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