bluuebunny/crossref_metadata_2025 huggingface dataset:
The Challenges Facing Local Government Communication Officers: The Case of Dar es Salaam City, Tanzania
Authors: Kazinja Deodatus Galeba
Published: January 2024

Government exists to deliver quality and equitable services amidst increasing public expectations and growing fiscal pressures. One of the key aspects for the delivery of services is effective communication handled by communication staffs. The execution of government communication officer’s role is widely experiencing a myriad of challenges of different patterns from one country to another.   This paper aimed to identify the challenges faced by communication staff at local councils in Dar es Salaam, which comprises five municipal councils. The study adopted a qualitative approach method and used purposive sampling to select nine (9) communication officers and five (5) Executive Directors) making a sample size of 14 respondents were attended in-depth interviews, observation and documentary review as data collection technique. The gathered data was thematically analysed. The study has revealed that the major challenges facing communication staffs in Dar es Salaam city were organisational structure and misunderstanding of the roles and responsibilities of communication officers leading to other challenges such as budget constraints, poor working environment, insufficient cooperation from other departments and lack of common statutory document guiding their communication functions. The study concludes that, communication activities in five municipal councils of Dar es Salaam were largely not a management function as many of communication officers were not involved in the management meeting where the major decisions about councils were done. The study recommends communication activities to be a management function that will allow communication staffs to be part of committee management meetings.
Agro-climatic Update of Favorable Areas to the Cultivation of Robusta and Arabusta Coffee in Côte d'Ivoire
Authors: Brou Kouamé , Fernand Yao Guy , Derving Baka , Emmanuel Kassin Koffi , Mamadou Ouattara Bala , Kouadio Amani , Lopez Essehi Jean , Jean-Marc Sery Drolet , Amani Konan
Published: January 2024

Following a drastic fall in coffee production, Côte d'Ivoire has made it a priority to revive its coffee-growing industry. This requires the development of regionalized technical itineraries adapted to climate change. To this end, agro-climatic analyzes were carried out using data from 55 rain gauge stations covering the period from 1985 to 2019. This involved cross-referencing the climatic parameters calculated, taking into account the climatic requirements of coffee trees (Robusta and Arabusta) to define homogeneous agro-climatic zones in the forest and pre-forest zones bounded by the 8th parallel north. The results show that 70.47% of the area is suitable for growing Robusta coffee, compared with 11.37% for Arabusta. The mountainous west remains generally favorable to growing both varieties of coffee. The study also updated information on the agro-climatic suitability of coffee-growing areas.
Biochemical Studies of Annatto Coloured Guava Beverages on Storage
Authors: Kumar Anuj , Singh Krishan Kumar , Gupta Sachi , Harendra  , Singh Ravi Shankar , Singh Gambhir , Singh Manish , Pathak Sanjay
Published: January 2024

A study was carried out on biochemical studies of guava beverages during storage in Laboratory of the Department of Post-harvest Technology, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya during 2018-19. Pink or red guava is generally used in processing industry due to its attractive pulp colour, making a significant contribution to food industry. Colour is an integral part of any processed food product since colour makes the processed food product attractive. In the present experiment, different amounts of annatto seed were used for adding color to white fleshed guava beverages, i.e., RTS and Squash. The results reveal that 0.8 g annatto seeds were found the most appropriate quantity for colouring one-litre RTS and 2 g annatto seeds for coloring one litre squash. It was also observed that the guava RTS and squash retained normal annatto color for eight months, thereafter, both the beverages started showing non-enzymatic browning during storage. The extract of annatto seeds was also found to act as preservative for both the processed products of guava.
Modern Phenotyping: A Paradigm of Present Need in Crop Improvement
Authors: Omprakash  , Thakur Padma , Aparna  , Dogra Prerna , Bairwa S. K. , Meena Santosh K. , Chandra Kailash
Published: January 2024

Modern phenotyping is intended to develop and establish the understanding of quantitative traits. Development of crops enriched with improved stress resilience and high yield potential, made it necessary to look into plant biological process that are responsible to crop improvement. Plant breeding aims to accelerate the genetic gain by utilizing modern high throughput phenotyping approaches which established the association between genotype and phenotype over the time and offers also elucidation of complex plant characters/phenotypes. Therefore, modern phenotyping or high throughput is forefront of future crop improvement. The major advantage of this innovative technique is monitoring of plants through nondestructive manner using effective imagining methodologies to gather the data for studies of complex characters in quantitative manner which are directly or indirectly related to plant yield, growth and to combat against biotic and abiotic stress. With a view to above facts this paper explains modern phenotyping approaches for crop improvement.
Response of Summer Forage Cowpea (Vigna unguiculata L.) to Spacing and Seed Rate
Authors: Joshi A. M. , Patel P. M. , Dharaviya Rahul G. , Patel J. K.
Published: January 2024

A field experiment on “Response of summer forage cowpea (Vigna unguiculata L.) to spacing and seed rate” was carried out during summer 2022 on loamy sand soil of Agronomy Instructional Farm, C. P. College of Agriculture, SardarkrushinagarDantiwada Agricultural University, Sardarkrushinagar. The experiment was laid out in split plot design with four replications. The result revealed that significantly the highest plant height was recorded under the line sowing at 30 cm. Higher numbers of branches per plant and leaf area per plant were observed under the line sowing at 45 cm. Cowpea sown at narrow row line sowing at 30 cm produced significantly the highest green forage and dry forage yield. The maximum net realization and benefit cost ratio were recoded under the line sowing at 30 cm. Seed rate of 50 kg/ha recorded significantly higher plant population and plant height. Higher number of branches per plant and leaf area per plant were recorded with seed rate of 30 kg/ha. Higher green forage and dry forage yield were recorded under seed rate of 50 kg/ha. The maximum net realization was accured with the seed rate of 50 kg/ha. The maximum benefit cost ratio was accured with the seed rate of 40 kg/ha.
The Effect of Percutaneous Vertebroplasty in Glucocorticoid Induced Osteoporotic Vertebral Compression Fractures: A Case Report
Authors: Ryu Jae Hyung , Kim Yu Jin , Choi Sang Sik
Published: January 2024

A 73-year-old woman with secondary adrenal insufficiency, who discontinued denosumab injection 9 months ago, presented with severe back pain. She was already diagnosed with an acute L1 compression fracture refractory to a month-long conservative treatment. Consequently, L1 percutaneous vertebroplasty (PVP) was performed, but the patient continued to complain of persistent lower back pain. Subsequent magnetic resonance imaging (MRI) revealed acute compression fractures at L2 and L5 vertebral body. After additional PVPs at L2 and L5, the patient experienced a dramatic reduction in pain. However, three weeks later, a new compression fracture occurred at L3, and she is currently undergoing conservative treatment. Percutaneous vertebral augmentation (PVA) is a safe and immediately effective treatment for glucocorticoid-induced osteoporosis (GIOP)-related osteoporotic vertebral compression fracture (OVCF) when pain is not controlled by conservative treatment. Abrupt discontinuation of prolonged Denosumab treatment can lead to rebound fractures; therefore, transitioning appropriately according to guidelines is recommended.
Effect of Integrated Nutrient Management on Chickpea Productivity and Soil Fertility Status under Rice – Chickpea Cropping System at Farmers Field of Balaghat District of Madhya Pradesh, India
Authors: Thakur Risikesh , Bisen N. K. , Shrivastava A. K. , Rai S. K. , Sarvade S.
Published: January 2024

Chickpea (Cicer aeritinum) is one of most important pulse crop which is grown in rabi season. The availability of nutrients in the soil for plant utilization is known to be affected not only by the inherent soil characteristics but also by the use of fertilizers and management practices followed for crop production. Therefore, a study on the effect of integrated application of inorganic fertilizers and organic manure (vermicompost) on rice productivity at farmer field was carried out at Balaghat district of Madhya Pradesh. In between the technology intervention, human resource development components were also included to improve the farmers understanding and skills about the demonstrated technology on nutrient management aspects. The demonstrations were conducted at different farmers' field at villages viz. Koppe, Chillod and Lendejhari on chickpea (variety JG 63) during rabi season 2018-19 and 2019-20 under Indian Council of Agricultural Research funded Project on Farmer FIRST, College of Agriculture, Balaghat (M.P.). Based on the basic soil properties of farmer’s field, the present experiment included four treatments viz., T1 = Farmer Practice (as Control), T2 = 100% NPK, T3 = 100% NPK + Zn, T4 = 75% NPK+ 5t/ha FYM ha and T5 = 75% NPK + 5t FYM ha-1+ Biofertilizers (BGA/Rhizobium& PSB). Results indicated that the highest average yield of chickpea was achieved in 75% NPK + 5t FYM ha-1+ Biofertilizers treatment, whereas, lowest yield was recorded in farmer’s practice. The highest increase in yield (50.7%) was observed with 75% NPK + 5t FYM ha-1+ Biofertilizers, followed by 75% NPK + 5t FYM ha-1 treatments (47.5%) over farmer’s practice.
Influence of Soil Parameters and Sowing Technics on Different Genotypes of Pearl Millet (Pennisetum glaucum (L.). R. Br
Authors: Jangorzo Nouhou Salifou , Sabiou Nana Salima Mouhtari , Sadda Abou-Soufianou , Kassari Issoufou Ango
Published: January 2024

Productivity improvement by adapting varieties to their environment was a major concern in the Sahel countries.  Climatic constraints and low soil fertility are the main factors conditioning millet yield. The objective of this study is to evaluate the influence of edaphic parameters, sowing technics, and fertilization on the improvement of eight genotypes of millet. For this, a trial including eight varieties of millet in split plot was installed on the experimental station of CERRA in Maradi in 2020 during the rainy season. Soil samples at a depth of 20 cm were collected at the beginning and the end of experiment. Soil pH, organic carbon, and assimilable phosphorus were determined. Two sowing technics, seed balls, and direct sowing were applied. In seed balls, two types of fertilizer were used: the NPK (15-15-15) and ash. Phenology parameters and grain yield of each variety was measured. A statistical analysis of these data showed that edaphic parameters do not significantly influence yield. However, a significant variation in grain yield was observed among genotypes. Specifically, the variety ICMV IS 89305 exhibited a significantly higher grain yield (789 +/- 590 kg ha-1) compared to ICVH 18 (348+/-289 kg ha-1). Moreover, the different types of treatments applied to the seedlings showed a significant difference in terms of grain yield. The SSB treatments yielded more (1101+/-541 kg ha-1) than the BSC (480+/-463 kg ha-1) and BSE (317+/-322 kg ha-1) ball treatments. These results highlight substantial variability both within and between treatments. The positive effect of seed balls and fertilizer included vary according to the context. Specifically, when rainfall is scarce, seed balls prove to be non-efficient in improving the yield of millet.
The Importance and Components of Economic Cooperation among Red Sea Countries
Authors: Afifi Zuhair Khalid
Published: January 2024

In an era marked by interconnectedness and global interdependence, the Red Sea region stands as a pivotal nexus linking diverse nations with shared opportunities and challenges. The importance of economic cooperation among Red Sea countries cannot be overstated, as it not only holds the potential to bolster individual national economies but also to foster regional stability, enhance sustainable development, and create a pathway towards mutual prosperity. This strategic waterway, teeming with economic potential, serves as a conduit for trade, investment, and collaboration, urging nations along its shores to recognize the mutual benefits of collective economic endeavors. In this dynamic context, fostering collaboration among Red Sea countries emerges not only as an economic imperative but also as a diplomatic and geopolitical necessity, reflecting the growing recognition that shared interests transcend national borders and can be best pursued through collective action. This paper offers a general literature review on the topic of the importance and components of economic cooperation among Red Sea countries. This literature review synthesizes existing research on the importance and components of economic cooperation among Red Sea countries. The Red Sea region, characterized by its strategic geopolitical position, is home to a diverse group of nations with unique economic challenges and opportunities. Scholars have extensively explored the potential benefits of fostering economic collaboration in this region, emphasizing the crucial role it plays in promoting regional stability, sustainable development, and mutual prosperity.
Design of Control System of Oil Collection Device
Authors: Liaoyuan Wang , Zhiqiang Liu , Zhiguang Li
Published: January 2024

The South-to-North Water Diversion project is a large water conservancy project implemented by the Chinese government to solve the water shortage problem in North China, but the oil slick pollution is an important problem. Aiming at the problem of oil slick pollution, a control system of oil slick collection device is designed in this paper. First of all, the design idea of intercepting first, then collecting, and then separating was determined, and the software was programmed. The simulation of Proteus software showed that the control program was stable and reliable, the pressurizing device could realize manual and automatic control respectively, and the oil-water separation device could realize the control of the three valves.
Assessment of Genotype X Environment Interaction and Seed Yield Stability in Sesame (Sesamum indicum L.) Using AMMI Analysis
Authors: Patel Manoj Kumar , Tiwari Deepti , Sharma Versha , Singh Dhirendra
Published: January 2024

Sesame is considered as an important oilseed crop in terms of nutritional and medicinal properties. Seed yield of any crop is highly labile to environmental factors, which may cause significant reduction in the yield performance. To get substantial stable yield production in crops like sesame, there is urgent need to identify stable genotypes that perform well under different environmental conditions. Thus, the present study has been planned with the aim to assess genotype x environment interaction (GEI) and stability analysis for seed yield per plant using additive main effect and multiplicative interaction (AMMI) model. The experiment involved evaluation of 20 sesame genotypes in randomized complete block design (RCBD) with three replications under three artificially created environments by providing different levels of fertilizers.  The environment wise analysis of variance (ANOVA) revealed significant genotypic variance across all the environments. Additionally, AMMI ANOVA revealed significant environment, genotypes and GEI components. GEI component was further classified to interaction principal components (IPC), IPC1 and IPC2, which explain 66.18% and 33.82% of variance due to GEI, respectively. Further, through different stability indices (ASV and GSI) and AMMI biplots, it was revealed that genotype RT-346 and RT-351 are considered as stable genotypes and these can be further recommended to farmer under varying fertility conditions.
Determination of Perception and Knowledge of Specimen Rejection Criteria in the Laboratory among Medical Doctors in Southern Nigeria
Authors: Jeremiah Igunma A. , Mienye Bob-Manuel , Ebeigbe Ejime
Published: January 2024

Background: Laboratory diagnosis plays a major role in the clinical management of patients, as such, specimen handling errors should be avoided at all costs. Laboratory results are largely dependent on the quality and conditions of the specimens received for analysis. Every laboratory has a set of standard rejection criteria for samples.

Since the pre-analytical stage of specimen handling lies in the purview of the medical practitioners who make the request, the aim of this study was to assess the knowledge of medical doctors regarding specimen appropriateness and their perception of specimen rejection criteria.

Methods: A descriptive cross-sectional survey was performed using a Google form which was distributed to medical practitioners practising in the southern part of Nigeria through various medical association WhatsApp groups, between April and September 2021. The self-administered questionnaire made up of three sections was used to obtain data on socio-demographic characteristics, the knowledge, and perception of medical doctors regarding good sample management practices. 

Results: Most of the respondents were senior registrars, medical officers and consultants employed in Teaching Hospitals.

50 (50%) of the doctors had good knowledge of sample rejection, while 30(30%) had poor knowledge. In the same vein, 80(80%) of the respondents had good perception of specimen rejection criteria, while four ( 4% ) had poor perception.

The relationship between the knowledge of respondents on sample rejection criteria and their office ranks was statistically significant (p<0.05) as well as the association between the facilities the doctors worked in and their knowledge of sample rejection criteria.

Conclusion: Since a significant percentage of doctors still demonstrate inadequate knowledge and perception, all hands must be on deck to improve knowledge regarding specimen collection and handling. The authors believe that this is remediable by improved training and quality assurance measures.
Analysis of the Impact of Exchange Rate on Price Level in Nigeria
Authors: Maureen Okaforocha Chika , Muhammed Sule , Okafor Vicent Chuks , Itodo Itodo Christian
Published: January 2024

The study focus on Analysis of the Impact of Exchange Rate on Price Level in Nigeria from 1988 to 2016 with variables as Inflation, exchange rate, tariff rate, import and interest rate. The research employed the Dynamic Ordinary Least Square (DOLS) regression method with the pre-test of Augmented Dickey Fuller (ADF) unit root test. The regression result showed a negative and insignificant relationship between exchange rate and inflation, tariff rate was negative and significant in relationship with inflation, while import was positively and insignificantly related to inflation, interest rate was having a positive but not significant relationship with inflation. We recommend that moderate or realistic tariff rate be negotiated among trading partners. Also local production of goods for export that will counter the negative impact of import to avoid imported inflation and strict monitoring of the activity of CBN and commercial banks in exchange rate dealing to avoid unnecessary and unproductive use of dollars.
Lampung Natural Zeolite Dopped with of ZnO-TiO2 Metal Oxide as Catalyst for Biodiesel Production
Authors: Al Muttaqii Muhammad , Marbun Maja Pranata , Priyanto Sugeng , Sibuea Andreas , Simanjuntak Wasinton , Syafaat AM Fuad , Silalahi Raja Havier Samuel Huttur , Alviany Riza , Maryani Tri , Sulistyaningsih Triastuti , Prasetyo Erik , Sudibyo Sudibyo , Yati Indri
Published: January 2024

Research has been carried out on making biodiesel from palm oil using natural zeolite catalysts impregnated with metal oxides such as zinc oxide and titanium oxide. This research aims to produce biodiesel using natural zeolite and ZnO-TiO2/NZ catalysts. The catalysts were analyzed using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning Electron Microscope (SEM), and Brunauer-Emmet-Teller (BET). The catalyst was tested in the transesterification reaction to produce biodiesel. The mole oil and methanol ratio varied from 1:15, 1:18, and 1:20. In addition, the biodiesel product was analyzed using Gas Chromatography-Mass Spectroscopy (GC-MS). The results showed the optimum condition for converting triglycerides to 1:18 variation of oil:methanol was 60.53%using a ZnO-TiO2/NZ catalyst. The ZnO-TiO2/NZ catalyst is very promising for use as a catalyst for converting palm oils into biodiesel.
Interaction of nebulin SH3 domain with titin PEVK and myopalladin: implications for the signaling and assembly role of titin and nebulin
Authors: Ma Kan , Wang Kuan
Published: December 2002

Skeletal muscle nebulin is thought to determine thin filament length and regulate actomyosin interaction in a calcium/calmodulin or S100 sensitive manner. We have investigated the binding of nebulin SH3 with proline‐rich peptides derived from the 28‐mer PEVK modules of titin and the Z‐line protein myopalladin, using fluorescence, circular dichroism and nuclear magnetic resonance techniques. Of the six peptides studied, PR2 of titin (VPEKKAPVAPPK) and myopalladin MyoP2 (646VKEPPPVLAKPK657) bind to nebulin SH3 with micromolar affinity (∼31 and 3.4 μM, respectively), whereas the other four peptides bind weakly (>100 μM). Sequence analysis of titins reveals numerous SH3 binding motifs that are highly enriched in the PEVK segments of titin isoforms. Our findings suggest that titin PEVK and myopalladin may play signaling roles in targeting and orientating nebulin to the Z‐line during sarcomere assembly.
Increased expression of vascular endothelial growth factor in placentas of p57Kip2 null embryos
Authors: Matsuura Toshiki , Takahashi Katsuhiko , Nakayama Keiko , Kobayashi Takao , Choi-Miura Nam-Ho , Tomita Motowo , Kanayama Naohiro
Published: December 2002

Placentas of mice lacking p57Kip2 expression have trophoblastic hyperplasia. To elucidate the mechanism underlying this phenomenon, we studied expression of two angiogenic factors, vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF). Immunohistochemical analysis with anti‐VEGF antibodies indicated that VEGF expression was stronger and more clearly detectable in placentas of p57Kip2 null embryos compared to wild‐type placentas. PlGF showed no significant differences between placentas of p57Kip2 null and wild‐type embryos. In quantitative analysis, placentas of p57Kip2 null embryos showed higher VEGF messenger (m)RNA and protein levels than did wild‐type placentas. PlGF mRNA and protein levels were not significantly different. These findings suggest that VEGF is involved in the hyperplasia that occurs in placentas of p57Kip2 null embryos.
Antioxidants induce different phenotypes by a distinct modulation of signal transduction
Authors: Della Ragione Fulvio , Cucciolla Valeria , Criniti Vittoria , Indaco Stefania , Borriello Adriana , Zappia Vincenzo
Published: December 2002

Antioxidants are known to exert a preventive activity against degenerative diseases. Here, we investigated the mechanism of action of three antioxidants: resveratrol, which causes differentiation of HL‐60 cells, and hydroxytyrosol and pyrrolidine dithiocarbamate which, in the same model system, activate apoptosis. The expression profile of hydroxytyrosol‐treated cells showed the up‐regulation of several genes, including c‐junandegr1. Pyrrolidine dithiocarbamate activates both genes, while resveratrol increases uniquelyegr1. A selective modulation of signalling pathway explained this finding. All antioxidants up‐regulate Erk1/2, while only hydroxytyrosol and pyrrolidine dithiocarbamate activate c‐Jun N‐terminal kinase (JNK). Since JNK induces apoptosis by Bcl‐2 phosphorylation, we investigated this event. Bcl‐2 phosphorylation was increased by hydroxytyrosol and pyrrolidine dithiocarbamate and not by resveratrol. Our results indicate that the different phenotypical effects of antioxidants correlate with modulation of selective transduction pathways.
An expanded V2 receptor retention signal
Authors: Le Gouill Christian , Innamorati Giulio , Birnbaumer Mariel
Published: December 2002

Following ligand‐promoted internalization the human type 2 vasopressin receptor (hV2R) is not recycled to the cell surface after removal of the agonist. A retention motif consisting of a serine triplet present in the cytoplasmic tail was previously found to require for retention, but serine 357, and threonines 359, 360 located upstream were not examined. Evidence is now presented that substitution of these amino acids did not change V2 internalization although it reduced the levels of arginine vasopressin (AVP)‐induced phosphorylation as compared to the wild type (WT). Contrary to the WT hV2R, these mutant receptors were recycled to the cell surface after a 2 h incubation in the absence of AVP identifying these changed residues as additional members of the retention motif of the hV2R.
Identification of the region of AT2 receptor needed for inhibition of the AT1 receptor‐mediated inositol 1,4,5‐triphosphate generation
Authors: Kumar Vikas , Knowle Dieter , Gavini Narasaiah , Pulakat Lakshmidevi
Published: December 2002

Increase in the intracellular inositol triphosphate (IP3) levels in Xenopus oocytes in response to expression and activation of rat angiotensin II (Ang II) receptor AT1 was inhibited by co‐expression of rat AT2 receptor. To identify which region of the AT2 was involved in this inhibition, ability of three AT2 mutants to abolish this inhibition was analyzed. Deletion of the C‐terminus of the AT2 did not abolish this inhibition. Replacing Ile249 in the third intracellular loop (3rd ICL) of the AT2 with proline, corresponding amino acid in the AT1, in the mutant M6, resulted in slightly reduced affinity to [125I]Ang II (K
d=0.259 nM), however, did not abolish the inhibition. In contrast, replacing eight more amino acids in the 3rd ICL of the AT2 (at positions 241–244, 250–251 and 255–256) with that of the AT1 in the mutant M8, not only increased the affinity of the AT2 receptor to [125I]Ang II (K
d=0.038 nM) but also abolished AT2‐mediated inhibition. Interestingly, activation of the M8 by Ang II binding also resulted in increase in the intracellular IP3 levels in oocytes. These results imply that the region of the 3rd ICL of AT2 spanning amino acids 241–256 is sufficient for the AT2‐mediated inhibition of AT1‐stimulated IP3 generation. Moreover, these nine mutations are also sufficient to render the AT2 with the ability to activate phospholipase C.
Functional characterization of GcpE, an essential enzyme of the non‐mevalonate pathway of isoprenoid biosynthesis
Authors: Kollas Ann-Kristin , Duin Evert C , Eberl Matthias , Altincicek Boran , Hintz Martin , Reichenberg Armin , Henschker Dajana , Henne Anke , Steinbrecher Irina , Ostrovsky Dmitry N , Hedderich Reiner , Beck Ewald , Jomaa Hassan , Wiesner Jochen
Published: December 2002

The gcpE gene product controls one of the terminal steps of isoprenoid biosynthesis via the mevalonate independent 2‐C‐methyl‐D‐erythritol‐4‐phosphate (MEP) pathway. This pathway is utilized by a variety of eubacteria, the plastids of algae and higher plants, and the plastid‐like organelle of malaria parasites. Recombinant GcpE protein from the hyperthermophilic bacterium Thermus thermophilus was produced in Escherichia coli and purified under dioxygen‐free conditions. The protein was enzymatically active in converting 2‐C‐methyl‐D‐erythritol‐2,4‐cyclodiphosphate (MEcPP) into (E)‐4‐hydroxy‐3‐methyl‐but‐2‐enyl diphosphate (HMBPP) in the presence of dithionite as reductant. The maximal specific activity was 0.6 μmol min−1 mg−1 at pH 7.5 and 55°C. The k
cat value was 0.4 s−1 and the K
m value for HMBPP 0.42 mM.
A dual‐frequency approach for retrieving sea surface wind speed from TOPEX altimetry
Authors: Chen Ge , Chapron Bertrand , Ezraty Robert , Vandemark Douglas
Published: December 2002

More than a dozen of wind speed (U) algorithms have been proposed during the past 2 decades, as a result of a continuing effort to improve altimeter wind measurement. The progress in terms of accuracy, however, is seen to be rather slow. The reported root mean square (RMS) error of prevailing algorithms varies mostly between 1.6 and 2.0 m/s for the dominant wind regime. As far as the TOPEX altimeter is concerned, three measured quantities, namely, the radar cross sections from Ku and C band (σKu and σC), as well as the significant wave height (Hs), have been used in previous algorithm developments, resulting in a variety of single‐, dual‐, and three‐parameter model functions. On the basis of the finding of a banded dependency of the U–σKu relationship on σC a new approach for retrieving altimeter wind speed, termed linear composite method (LCM), is proposed in this study. The LCM model function appears as a set of σC‐dependent linear relations between U and σKu. A unique advantage of this approach is that it allows the algorithm to be tuned or expanded for a given range of wind speed without affecting the rest. Over 1.7 million coincident TOPEX/NASA scatterometer (NSCAT) and TOPEX/QuikSCAT data covering a period of 2.5 years are used to adjust the model. Validation against extensive buoy measurements indicates that the LCM algorithm is almost unbiased and has an overall RMS error of 1.56 m/s, which is 12% lower compared to the algorithm in operational use [Witter and Chelton, 1991]. In addition, a small (2.5–6%, depending on the reference data set) but significant improvement is found for the LCM when compared to the most recent dual‐parameter algorithm [Gourrion et al., 2002].
Sources and processes affecting levels and composition of atmospheric aerosol in the western Mediterranean
Authors: Rodríguez Sergio , Querol Xavier , Alastuey Andrés , Plana Felicia
Published: December 2002

Airborne particulate composition in the western Mediterranean atmosphere was investigated by means of simultaneous sampling of PM10 (particulate matter <10 μm) at a rural site (Ebro basin) and an urban one (Barcelona) in eastern Spain in order to evaluate the natural and anthropogenic contributions. The major regional particulate pollutants were nitrate, sulfate, and carbonaceous aerosols, whereas sea salt and mineral dust accounted for the main natural contribution. Owing to the thermodynamic properties of nitrogenous species, the load of nitrate in PM10 attains a maximum in the cold season (30% of bulk PM10 as rural and urban means in winter and <15% in summer). Conversely, in summer, sulfate attains a maximum load in PM10 (15–35% of bulk PM10 in summer and 5–20% in winter at two sites). High‐sulfate events in summer were associated with ozone episodes at the rural site, which suggests that photochemical processes play a significant role in the production of particulate pollutants. High mineral dust concentrations were simultaneously recorded at the two sites during African dust outbreaks, when the dust load accounted for 50–80% of bulk PM10 at the rural site and 20–45% at the urban site. Daily dust concentrations in the range 20–25 μg/m3 (40–50% of the daily EU limit value for PM10) are frequently recorded during these African events. Analysis of satellite observations and meteorology shows that African dust outbreaks occur over large areas in southern Europe and interferes with the monitoring of levels of anthropogenic PM10 aerosols regularly performed in the national air quality networks.
Toward improved identifiability of hydrologic model parameters: The information content of experimental data
Authors: Vrugt Jasper A. , Bouten Willem , Gupta Hoshin V. , Sorooshian Soroosh
Published: December 2002

We have developed a sequential optimization methodology, entitled the parameter identification method based on the localization of information (PIMLI) that increases information retrieval from the data by inferring the location and type of measurements that are most informative for the model parameters. The PIMLI approach merges the strengths of the generalized sensitivity analysis (GSA) method [Spear and Hornberger, 1980], the Bayesian recursive estimation (BARE) algorithm [Thiemann et al., 2001], and the Metropolis algorithm [Metropolis et al., 1953]. Three case studies with increasing complexity are used to illustrate the usefulness and applicability of the PIMLI methodology. The first two case studies consider the identification of soil hydraulic parameters using soil water retention data and a transient multistep outflow experiment (MSO), whereas the third study involves the calibration of a conceptual rainfall‐runoff model.
The constitutive equation and flow dynamics of bubbly magmas
Authors: Llewellin E. W. , Mader H. M. , Wilson S. D. R.
Published: December 2002

A generalized constitutive equation for bubbly liquids is presented which successfully reproduces the expected viscosity response for both steady flows with varying capillary number Ca (a measure of the bubble deformation) and unsteady flows with varying dynamic capillary number Cd (a measure of the steadiness of the flow) previously given in separate studies. The constitutive equation is given in terms of observable material and flow parameters and is valid at least up to Ca ∼ O(1000) and Cd ∼ O(10). Analytical solutions are presented for steady, simple‐shearing flow (Ca variable) and oscillatory flow with small total‐strains (Cd variable). The special case of steady flow in a circular pipe—analogous to magma flow in a volcanic conduit—is investigated. Velocity profiles across the conduit are found to be parabolic or plug‐flow depending on a dimensionless number, the conduit capillary number Cc. Plug flow is predicted for Cc ≈ 4 which is in the mid‐range for volcanic‐eruption conditions.
Analytical representation of the plasmasphere electron temperature distribution based on Akebono data
Authors: Kutiev Ivan , Oyama Kohichiro , Abe Takumi
Published: December 2002

A new approach is used to reveal the average thermal structure of plasmasphere at altitudes between 1000 and 10,000 km. This paper only considers the plasmasphere inside L = 3, and this region of space is sliced at L = 2 to one internal (denoted as equatorial) and one external (denoted as midlatitude) part. Each of these parts is divided into four altitude/local time zones: northern and southern daytime and northern and southern nighttime. Electron temperature (Te) distribution measured along every individual orbit within each zone is approximated by simple expressions that are functions of the geomagnetic latitude or L. The fitting is performed independently to each zone, and two coefficients are extracted from the individual fits: Te value at the equatorward border and the coefficient scaling the latitudinal shape. These coefficients are accumulated in each zone in order to obtain its average Te structure as a function of altitude. The fitting coefficients exhibit large scatter, which reflects the large day‐to‐day variability of plasmasphere Te. The fitting error is estimated at 6% and 12% for the equatorial and midlatitude zones, respectively. The average fit coefficients are used to check for seasonal variations in each zone and for a possible hemispheric asymmetry. It is determined that the winter sunlit plasmasphere is hotter than the summer one; the case for nighttime is reverse. The day/night amplitude is larger in the winter than in the summer, and the seasonal differences are more pronounced in the Southern Hemisphere. The latitude gradients of Te reveal a hemispheric asymmetry, which is largest during northern daytime winter. Solar activity is found to affect the plasmasphere Te. During the day at 3000 km and L = 2, Te increases by ∼2000°K when F10.7 changes from 70 to 300. The nighttime increase is ∼1000°K. At the equator, Te shows weaker dependence on solar activity. The average heat flux through 3000 km altitude is estimated at 3.7 × 109 (eV cm−2 s−1) during the day and 1.6 × 108 (eV cm−2 s−1) during the night.
A variable‐resolution stretched‐grid general circulation model and data assimilation system with multiple areas of interest: Studying the anomalous regional climate events of 1998
Authors: Fox‐Rabinovitz Michael S. , Takacs Lawrence L. , Govindaraju Ravi C.
Published: December 2002

The new stretched‐grid (SG) design with multiple (four) areas of interest, one at each global quadrant, is implemented into both a SG general circulation model (GCM) and a SG data assimilation system (DAS). The four areas of interest include the United States/northern Mexico, the El Niño area/central South America, India/China, and the eastern Indian Ocean/Australia. Both SG‐GCM and SG‐DAS annual (November 1997 to December 1998) integrations are performed with 50‐km regional resolution. The efficient regional downscaling to mesoscales is obtained for each of the four areas of interest, while the consistent interactions between regional and global scales and the high quality of global circulation are preserved. This is the advantage of the SG approach. The global variable‐resolution DAS incorporating the SG‐GCM has been developed and tested as an efficient tool for producing regional analyses and diagnostics with enhanced mesoscale resolution. The anomalous regional climate events of 1998 that occurred over the United States, Mexico, South America, China, India, African Sahel, and Australia are investigated in both simulation and data assimilation modes. The assimilated products are also used, along with gauge precipitation data, for validating the simulation results. The obtained results show that the SG‐GCM and SG‐DAS are capable of producing realistic high‐quality simulated and assimilated products at mesoscale resolution for regional climate studies and applications.
Trends and uncertainties in thermal calibration of AVHRR radiometers onboard NOAA‐9 to NOAA‐16
Authors: Trishchenko Alexander P. , Fedosejevs Gunar , Li Zhanqing , Cihlar Josef
Published: December 2002

Satellite measurements from the infrared (IR) channels of the Advanced Very High Resolution Radiometer (AVHRR)/NOAA have been used to derive many important atmospheric, cloud, and surface parameters for weather prediction, climate modelling, and a variety of environmental studies. Calibration accuracy of the satellite data directly affects accuracies of the derived parameters. So far, very limited attention has been given to the calibration uncertainties of the IR channels. In this study, we analyzed the calibration data of AVHRR radiometers onboard polar orbiting satellites NOAA‐9 to NOAA‐16. We utilized Global Area Coverage (GAC) data, approximately one orbit per month throughout the lifetime of the instruments, available from the NOAA Satellite Active Archive (SAA). AVHRR IR channels 3B, 4, and 5 are calibrated in‐flight. Calibration coefficients are derived from measurements of radiance emitted from an internal calibration target (ICT) and deep‐space (SP). The overall budget of uncertainties has been evaluated using an in‐flight calibration system that includes four thermal platinum resistance thermometers (PRTs) to monitor the ICT temperature. The measurement noise (NEΔT) was found to vary from 0.03 K to 0.3 K at 300 K depending on the channel and radiometer, and it increases significantly as temperature decreases. Systematic degradation of the radiometric sensitivity of the IR detectors was observed during the lifetime of a radiometer, although the annual rate of degradation is rather small (typically below 1% per year). A significant correlation between the calibration gain and temperature of a radiometer is often observed. The degradation of a sensor's radiometric sensitivity reduces the radiometric resolution of the AVHRR measurements and expands the upper limit of the measured brightness temperature. PRT measurements are subject to significant orbital variation (up to 7 K) and inconsistency for some AVHRR radiometers. The inconsistency was especially large for the AVHRR onboard NOAA‐12 (up to 4 K) and NOAA‐14 (up to 3 K), but it is less than 0.5 K for NOAA‐15 and ‐16. The inconsistency may signify the presence of a thermal gradient across the ICT. Some systematic differences between PRT measurements may also indicate inaccurate characterization of the PRT sensors, for example for AVHRR/NOAA‐11 and ‐14. The impact of the varying thermal state of the AVHRR environment on the accuracy of AVHRR in‐flight thermal calibration was assessed. We found this impact to be significant (up to 0.5 K and more), and proposed a physical model to explain it. We recommend this model for AVHRR operational in‐flight calibration, especially during solar radiative contamination events. Estimates of the PRT thermal response time constant were derived and found to vary between 0.5 and 1.5 min among AVHRR radiometers. Overall, we found somewhat higher uncertainties in AVHRR thermal measurements than were assumed previously.
Light absorption and thermal measurements of black carbon in different regions of Canada
Authors: Sharma S. , Brook J. R. , Cachier H. , Chow J. , Gaudenzi A. , Lu G.
Published: December 2002

A study was conducted to determine the relationship between light absorption measurements from an aethalometer and a particle soot absorption photometer (PSAP) and black carbon mass concentrations across Canadian environments ranging from urban to remote areas. To achieve this, filter samples were collected for thermal analysis of black carbon simultaneously with light absorption measurements at several locations in Canada. Previously, it has been shown that the k relating particle light absorption to black carbon measured with an aethalometer changes with age, type, and composition of the aerosol, which varies with time and by space [Liousse et al., 1993; Petzold and Niessner, 1995; Lavanchy et al., 1999; Ruellan and Cachier, 2000]. Consequently, to convert light absorption measurements to the black carbon mass, the standard values used for k of 19 m2 g−1 for aethalometer and 10 m2 g−1 for PSAP, respectively, need to be fine‐tuned to fit the conditions at the site of interest to obtain the site‐specific attenuation, referred to as k(S.S.). Our results also indicate that k(S.S.) varies; on a broad scale, from remote continental to rural, suburban, and urban locations and from winter to summer and, on a small scale, within an urban area and from measurement to measurement at a single location. The range of median k(S.S) values observed was from 6.4 m2 g−1 to 20.1 m2 g−1. We suggest that the variability is connected to the distribution of sources and processes contributing to the carbonaceous aerosols at the sites.
Ventilated and unventilated air temperature measurements for glacier‐climate studies on a tropical high mountain site
Authors: Georges Christian , Kaser Georg
Published: December 2002

In this paper, artificially ventilated and unventilated temperature measurements logged by high‐elevation automatic weather stations (AWS) in the tropical Cordillera Blanca, Perú, are compared. Both temperatures are measured with the same sensor and radiation shield by periodic artificial ventilation. The analyzed time series range from October 1999 until May 2001. The temperature differences ΔT = Tunvent. − Tvent. show a persistent daily cycle with a nighttime mean value of 0.3 K and a daytime mean of 1.3 K. The daytime period of ΔT is characterized by a late morning and an early afternoon maximum and a slight secondary noon minimum. The cycle is most pronounced during the dry season, but is only slightly reduced in the wet season. It is shown that the daily cycle is mainly caused by incoming shortwave radiation and that the resulting temperature difference depends on the irradiation angle to the radiation shield. A simple radiation geometry model is proposed for the explanation of ΔT. The modeled ΔT daily cycle strongly correlates with measured monthly mean ΔT daily cycles and can be used for respective corrections. In case of snow cover, the general cycle of ΔT remains, but additional deviations are caused by reflected shortwave radiation. These deviations cannot be modeled by using simple considerations. Therefore adequately ventilated air temperature measurements on glaciers and snow‐covered surfaces should be made. Natural ventilation suffices in the case of persistently high wind speeds; otherwise, artificial ventilation should be implemented whenever possible.
Reconstructing atmospheric histories from measurements of air composition in firn
Authors: Trudinger C. M. , Etheridge D. M. , Rayner P. J. , Enting I. G. , Sturrock G. A. , Langenfelds R. L.
Published: December 2002

This paper investigates the use of a numerical model of firn diffusion and bubble trapping in the reconstruction of atmospheric records from firn measurements. We describe the concept of mean age and effective age of tracers in firn air and how the growth rate of a tracer in the atmosphere can alter the effective age. We discuss an iterative method to assign effective ages to firn measurements for tracers with fairly simple atmospheric histories, taking into account atmospheric growth rate variations. We then develop a Bayesian synthesis inversion calculation for inverting firn concentration measurements. This calculation gives estimates of the atmospheric concentration record with uncertainties. The dating and inversion techniques are demonstrated here with carbon tetrachloride measurements from a long firn record from Law Dome, Antarctica. The techniques are then applied to measurements of a range of halocarbons in a companion paper by Sturrock et al. [2002].
Retrieving aerosol optical depth and type in the boundary layer over land and ocean from simultaneous GOME spectrometer and ATSR‐2 radiometer measurements 2. Case study application and validation
Authors: Holzer‐Popp T. , Schroedter M. , Gesell G.
Published: December 2002

Intensive research on the distribution of aerosols is being conducted within many international research programs (e.g., Global Energy and Water Cycle Experiment and International Global Atmospheric Chemistry Experiment). Obviously, satellite remote sensing allows for global monitoring; however, operational satellite observation has for a long time been limited to either the oceans or to UV‐absorbing aerosols. Therefore a new aerosol retrieval method, Synergetic Aerosol Retrieval (SYNAER), to derive aerosol optical depth and type, both over land and over ocean, was developed (see part 1 of this paper, Holzer‐Popp et al. [2002]). First, case studies showing its application and a validation using ground‐based and airborne measurements are presented. They show a good agreement with better than 0.1 in boundary layer aerosol optical thickness at 550 nm and indicate a detection of the correct aerosol type in most cases. Restrictions for the detection of aerosol type appear over bright surfaces and in areas with an aerosol optical depth less than 0.1 due to a low aerosol sensitivity in these situations. The method has been developed for the future operational use of similar sensor pairs Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY)/Advanced Along Track Scanning Radiometer (AATSR) and Global Ozone Monitoring Experiment 2 (GOME‐2)/Advanced Very High Resolution Radiometer (AVHRR). Thus SYNAER holds the potential to extract a 25‐year‐long climatological data set (1995–2020) from ERS‐2, Envisat, and METOP.