bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Inventory Management Practices on Operational Performance in Mombasa County Government, Kenya
Authors: Simwa Joram Tovesi , Barasa Peter Wamalwa
Published: March 2024

This study aimed at establishing the effect of inventory management practices on the operational performance of Mombasa County government. The specific objectives included the following: to examine the impact of JIT model on the operational performance of Mombasa County government; to assess the effect of Activity Based Costing (ABC) on the operational performance of Mombasa County government; to determine the impact of Economic Order Quantity (EOQ) on the operational performance of Mombasa County government and to establish the impact of stock taking practice on the operational performance of Mombasa County government. The research study reviewed Just in Time Theory, Systems theory and the transactional theory. This study used a descriptive survey design. The target population was all the 250 employees working in Mombasa County government that included ICT officers, Finance officers, Budgeting officers, Internal Audit officers and Procurement officers. Sample size of 96 employees was drawn from and was selected by the use of stratified random sampling. Data was collected using a questionnaire. Data analysis was done with the aid of SPSS version 28. Inferential statistics was displayed by the use of correlations and regression analysis. The ethical considerations for this study included confidentiality, informed consent, privacy and anonymity. Correlation analysis revealed that there was a significant correlation between the Operational Performance of the County Government of Mombasa and Activity Based Costing practice (β = 0.321, p˂ 0.05). This is followed by Economic Order Quantity X3 (β = 0.289, p˂ 0.05), Stocktaking X4 (β = 0.251, p˂ 0.05), and Just in Time Model X1 (β = 0.243, p˂ 0.05), in that order.
Assessing the Impact of Foreign Direct Investment on Unemployment Rate in Nigeria
Authors: Chike Okoli, Kingsley , Okeke Callistus Tabansi
Published: March 2024

Recent studies have shown that high rate of unemployment as currently witnessed in Nigeria, is one of the factors that can undermine the attainment of goal eight (Decent work and Economic growth) of Sustainable Development Goals (SDGs) by year 2030. Since foreign direct investment (FDI) is an important factor in creating jobs and improving economic growth, it is considered a veritable tool for reducing the unemployment level. Although there have been studies on FDI and unemployment in literature, there is hardly any study on the impact of FDI on rural and urban unemployment. The study pursued threefold objectives which are to ascertain the impact of FDI on aggregate unemployment in Nigeria; to examine the impact of FDI on urban unemployment rate in Nigeria and to determine the impact of FDI on rural unemployment in Nigeria. The study utilized data from 1990 to 2020 as well as dynamic ordinary least squares (DOLS) which eliminates problems of endogeneity and serial correlation. The theoretical framework of the study is anchored on the Keynesian theory of unemployment. The result obtained showed that FDI has a significant impact on aggregate and urban unemployment in Nigeria. However, FDI did not impact significantly on rural unemployment in Nigeria. To effectively use FDI to reduce unemployment, the Nigerian government needs to create an enabling business environment, including favorable investment policies, streamlined regulatory procedures, and infrastructure development plans. Encouraging collaboration between foreign investors and local stakeholders, promoting technology transfer, and implementing strategies to enhance the skill levels of the local workforce are also important aspects to consider.
Exploration of Native Trichoderma spp. from different Eco-Systems of the Canara Circle, Karnataka, India
Authors: Prashantha A.  , Suryanarayana V.  , Patil M. S.  , Krishnaraj, P. U.  , Hegde R. V.
Published: March 2024

Canara Circle of Karnataka, which fall under agro-climatic zones 9 and 10 has a very unique type of eco-system comprising mainly forest followed by horticulture and agricultural eco-systems. Soil borne diseases was seriously impacting quality and quantity of crop production yielding low profitability. No doubt, pesticides were effective, but have soil and environment impairments. Application of effective native Trichoderma sp. is the best in all angles. As this region being the organic district with diverse ecosystems, it is a treasure for exploring efficient Trichoderma spp. In this context, a roving survey was carried out during 2019 in seven (7) different taluks of Canara circle (Haliyal, Mundgod, Siddapur, Sirsi, Yellapura, Ankola and Kumta). Two rhizosphere soil samples of 250 g each were collected from agriculture, horticulture and forest eco-systems of each taluk totalling forty two (42). Among the rhizosphere soils tested by serial dilution technique on Trichoderma selective medium (TSM), highest number of Trichoderma isolates was from forest ecosystem (11) with maximum recovery (78.57%). Horticulture ecosystem followed next (9 isolates) with 64.28 per cent recovery and the agriculture ecosystem recorded the lowest Trichoderma isolates (7) with 50 per cent recovery.
Comparative Evaluation of Hydrogen Peroxide Levels in Patients with Periodontal Disease and Healthy Individuals–Pilot Study
Authors: Castro Marcelo Fernandes de , Chami Yasmin Maria Tatico , Oliveira Jasiel de , Perozini Caroline , Sendyk Wilson Roberto , Koga-Ito Cristiane Yumi , Pallos Debora , Tanaka Marcia Hiromi
Published: March 2024

Purpose: To assess the levels of hydrogen peroxide (H2O2) in crevicular fluid samples collected from patients with periodontal disease (PD) and periodontally healthy individuals.

Methods: Crevicular fluid samples were collected from three diseased sites in 20 PD patients and from three healthy sites in 11 periodontally healthy patients (control). Plaque indices, probing depths, clinical attachment levels, and bleeding on probing were measured. Subsequently, the collected samples were categorized into three groups: a gingivitis group (n=8), a periodontitis group (n=12), and a control group (n=11). The quantification of H2O2 content within these samples was analyzed using an H2O2/peroxidase test kit.

Results: Higher levels of H2O2 were found in the periodontitis group compared to group control and gingivitis (p<0.0001). Furthermore, the gingivitis group also shown elevated H2O2 levels compared to the control group (p<0.0001).

Conclusions: The findings suggest that the severity of periodontal disease could be associated with elevated levels of H2O2 in gingival crevicular fluid. Hydrogen peroxide may potentially serve as a biomarker for disease progression or for products aimed at enhancing H2O2 release in periodontal treatment. However, further investigations with larger sample sizes and longitudinal designs are necessary to corroborate and expand upon these preliminary observations.
Fluorescence spectroscopy as a tool for monitoring solubility and aggregation behavior of β‐lactoglobulin after heat treatment
Authors: Elshereef Rand , Budman Hector , Moresoli Christine , Legge Raymond L.
Published: June 2006

Denaturation and aggregation of whey proteins are of interest to the food and pharmaceutical industry due to the importance of final structure in functionality, impact on food texture, and the chemical stability of the final product. In this study, we demonstrate the potential of fluorescence spectrometry combined with multivariate chemometric methods for quantifying solubility and aggregation behavior of β‐lactoglobulin (β‐LG); a major whey protein and a frequent food ingredient. Heat‐induced aggregation of β‐LG was studied under different conditions including pH, temperature and heating durations. Results showed very good agreement between the fluorescence‐based predictions and measurements obtained by HPLC and gravimetric analysis regardless of the conditions. Standard normal variate (SNV), a signal preprocessing and filtering tool, was found to enhance the predictive accuracy and robustness of the fluorescence‐based model. © 2006 Wiley Periodicals, Inc.
Comparison of pulsed radiofrequency with conventional radiofrequency in the treatment of idiopathic trigeminal neuralgia
Authors: Erdine Serdar , Ozyalcin Nuri Suleyman , Cimen Ali , Celik Mehmet , Talu Gul Koknel , Disci Rian
Published: June 2006

The aim of this prospective, randomized, double‐blinded study was to evaluate the effect of pulsed radiofrequency (PRF) in comparison with conventional radiofrequency (CRF) in the treatment of idiopathic trigeminal neuralgia. A total of 40 patients with idiopathic trigeminal neuralgia were included. The 20 patients in each group were randomly assigned to one of the two treatment groups. Each patient in the Group 1 was treated with CRF, whereas each patient in the Group 2 was treated by PRF. Evaluation parameters were: pain intensity using a Visual Analogue Scale (VAS), patient satisfaction using a Patient Satisfaction Scale (PSS), additional pharmacological treatment, side effects, and complications related to the technique. The VAS scores decreased significantly (p<0.001) and PSS improved significantly after the procedure in Group 1. The VAS score decreased in only 2 of 20 patients from the PRF group (Group 2) and pain recurrence occurred 3 months after the procedure. At the end of 3 months, we decided to perform CRF in Group 2, because all patients in this group still had intractable pain. After the CRF treatment, the median VAS score decreased (p<0.001) and PSS improved (p<0.001) significantly. In conclusion, the results of our study demonstrate that unlike CRF, PRF is not an effective method of pain treatment for idiopathic trigeminal neuralgia.
The relationship of impulsivity to response inhibition and decision-making in remitted patients with bipolar disorder
Authors: Christodoulou T. , Lewis M. , Ploubidis G.B. , Frangou S.
Published: June 2006

Background

Impulsivity, a core feature of bipolar disorder (BD), is a multifaceted concept encompassing failure of response inhibition and poor decision-making. Abnormalities in these two cognitive domains have been reported in BD patients but their relationship with impulsivity has not been explored.

Methods

Twenty-five remitted patients with BD completed the Barratt Impulsiveness Scale (BIS) and performed the Hayling Sentence Completion Task (HSCT) and a computerized version of the Iowa Gambling task. The HSCT total errors scaled score was used as a measure of response inhibition while the gabling task score, which reflects participants' ability to make advantageous choices, was used a measure of decision making.

Results

Higher scores on the BIS attentional and non-planning subscales were respectively associated with more errors in the HSCT and less advantageous choices in the gambling task.

Limitations

All patients were medicated. Healthy participants were not included.

Conclusions

Viewed in the context of recent relevant studies our findings suggest that impulsivity, response inhibition and decision-making in BD may represent behavioural manifestations of the same underlying biological mechanism possibly linked to ventral prefrontal cortical function.
Mechanism of action of the endo‐(1 → 3)‐α‐glucanase MutAp from the mycoparasitic fungus Trichoderma harzianum
Authors: Grün Christian H. , Dekker Nick , Nieuwland Alexander A. , Klis Frans M. , Kamerling Johannis P. , Vliegenthart Johannes F.G. , Hochstenbach Frans
Published: June 2006

(1 → 3)‐α‐Glucanases catalyze the hydrolysis of fungal cell wall (1 → 3)‐α‐glucan, and function during cell division of yeasts containing this cell wall component or act in mycoparasitic processes. Here, we characterize the mechanism of action of the (1 → 3)‐α‐glucanase MutAp from the mycoparasitic fungus Trichoderma harzianum. We observed that MutAp releases predominantly β‐glucose upon hydrolysis of crystalline (1 → 3)‐α‐glucan, indicating inversion of the anomeric configuration. After having identified (1 → 3)‐α‐glucan tetrasaccharide as the minimal substrate for MutAp, we showed that reduced (1 → 3)‐α‐glucan pentasaccharide is cleaved into a trisaccharide and a reduced disaccharide, demonstrating that MutAp displays endo‐hydrolytic activity. We propose a model for the catalytic mechanism of MutAp, whereby the enzyme breaks an intrachain glycosidic linkage of (1 → 3)‐α‐glucan, and then continues its hydrolysis towards the non‐reducing end by releasing β‐glucose residues in a processive manner.
Identification of 188 conserved maize microRNAs and their targets
Authors: Zhang Baohong , Pan Xiaoping , Anderson Todd A.
Published: June 2006

MicroRNAs (miRNAs) represent a newly identified class of non‐protein‐coding ∼20 nt small RNAs which play important roles in multiple biological processes by degrading targeted mRNAs or repressing mRNA translation. After searching a genomic survey sequence database using homologs and secondary structures, we found 188 maize miRNAs belonging to 29 miRNA families. Of the 188 maize miRNA genes, 28 (15%) were found in at least one EST. A total of 115 potential targets were identified for 26 of the miRNA families based on the fact that miRNAs exhibit perfect or nearly perfect complementarity with their target sequences. A majority of the targets are transcription factors which play important roles in maize development, including leaf, shoot, and root development. Additionally, these maize miRNAs are also involved in other cellular processes, such as signal transduction, stress response, sucrose and cellulose synthesis, and ubiquitin protein degradation pathway. Some of the newly identified miRNA targets may be unique to maize.
Identification of the cytochrome P450 enzymes responsible for the ω‐hydroxylation of phytanic acid
Authors: Komen J.C. , Wanders R.J.A.
Published: June 2006

Patients suffering from Refsum disease have a defect in the α‐oxidation pathway which results in the accumulation of phytanic acid in plasma and tissues. Our previous studies have shown that phytanic acid is also a substrate for the ω‐oxidation pathway. With the use of specific inhibitors we now show that members of the cytochrome P450 (CYP450) family 4 class are responsible for phytanic acid ω‐hydroxylation. Incubations with microsomes containing human recombinant CYP450s (Supersomes™) revealed that multiple CYP450 enzymes of the family 4 class are able to ω‐hydroxylate phytanic acid with the following order of efficiency: CYP4F3A > CYP4F3B > CYP4F2 > CYP4A11.
Reduction of the Incidence of Neuroma Formation By Proximal Epineural Stripping: an Experimental Study in Rats
Authors: YILDIRIM A. M. , OKUR M. İ. , ÖZVEREN F. , ÖZERCAN R.
Published: June 2006

The effect of proximal epineural stripping on neuroma formation was studied in the peroneal nerve stumps of the rat. After transection of the peroneal nerve, the epineurium of the proximal stump was stripped back by 6 to 8 mm and the nerve fascicles left uncovered in the study group. The transected nerve was left untreated in the control group. All nerves were evaluated by light microscopy 6 months after the operation. Two neuromas occurred in 20 stumps after epineural stripping while 15 neuromas occurred in the control group. Based on histological data, we conclude that stripping of the epineurium may inhibit neuroma formation in the rat.
Seismicity in the Kingdom of Bhutan (1937–2003): Evidence for crustal transcurrent deformation
Authors: Drukpa Dowchu , Velasco Aaron A. , Doser Diane I.
Published: June 2006

We investigate moderate‐sized historic to recent earthquakes in the Bhutan Himalaya spanning the years from 1937 to 2003. We find that few moderate‐sized earthquakes occurred in the region during this time period. In order to better characterize the seismicity, we relocate all earthquakes and estimate focal mechanisms for events for which we have adequate data. We use first motion data for older events and waveform model digital seismograms for three earthquakes that occurred in 1980 (Mw = 6.4), 1995 (Mw = 5.4), and 2003 (Mw = 5.4). For the modern events, we utilize three techniques for focal mechanism and depth determination: regional full waveform time domain modeling of the two moderate (Mw = 5.4) events, and surface wave spectral method and body wave depth modeling approach for the Mw = 6.4 event. We find that the first motion and digital data focal mechanisms are mostly strike‐slip, with midcrustal to deep crustal depths. Although no recent great event has occurred along the main Himalayan thrust, the Indian plate is undergoing significant, midcrustal to deep crustal transcurrent deformation, likely due to oblique convergence of the Indian‐Asian collision in this region. Unlike oceanic‐continent oblique subduction, strike‐slip and thrust partitioning occurs throughout the crust, not in distinct zones. The geological and geophysical nature of the Bhutan Himalaya appears significantly different than other Himalayan regions due to the strike‐slip nature of many of the events, an out of sequence thrust fault, and the implications of deformation in the Shillong Plateau.
Spatial and temporal variability of the Brazil‐Malvinas Confluence and the La Plata Plume as seen by SeaWiFS and AVHRR imagery
Authors: Gonzalez‐Silvera Adriana , Santamaria‐del‐Angel Eduardo , Millán‐Núñez Roberto
Published: June 2006

Ocean color (OCTS, SeaWiFS) and sea surface temperature (AVHRR) images were used to evaluate spatial and temporal variability of the Brazil‐Malvinas Confluence and La Plata Plume (20° to 45°S and 40° to 65°W). The data set covers the period from January 1997 to June 2003. Chlorophyll and SST data were combined using Principal Component Analysis (PCA). The results yielded were used to identify and follow front displacements. PCA maps showed a close relationship with previous observations of currents behavior and the La Plata Plume. Firstly the analysis was performed on data retrieved from a monthly climatology, and the results show three remarkable features: a gradual increase of the northward intrusion of the La Plata Plume throughout the period lasting from summer to winter; the summer shape of the La Plata Plume showed a stronger penetration over the shelf on the Argentinean side of the estuary mouth; and the seasonal migration of the Brazil‐Malvinas Confluence. Monthly composites were then used and compared with discharge and wind data from scatterometers. The results show that increases on discharge led to a greater influence of the La Plata Plume over the continental shelf although during 1998 (El Niño) it did not penetrate farther north because of the unfavorable wind pattern (northerly). On the other side, during 2002, high discharge rates were associated with strong southerly winds, leading to a northern penetration of the plume. The same analysis was applied to daily images to show its application on locating the front's position. This analysis showed the same patterns.
Comparison of geophysical investigations for detection of massive ground ice (pingo ice)
Authors: Yoshikawa K. , Leuschen C. , Ikeda A. , Harada K. , Gogineni P. , Hoekstra P. , Hinzman L. , Sawada Y. , Matsuoka N.
Published: June 2006

Six different geophysical investigations, (1) ground‐penetrating radar, (2) DC resistivity sounding, (3) seismic refraction, (4) very low frequency (VHF) electromagnetic, (5) helicopter borne electromagnetic (HEM), and (6) transient electromagnetic (TEM) techniques, were employed to obtain information on the ice body properties of pingos near Fairbanks, Alaska. The surface nuclear magnetic resonance (NMR) data were also compared from similar sites near one of the study pingos. The geophysical investigations were undertaken, along with core sampling and permafrost drilling, to enable measurement of the ground temperature regime. Drilling (ground truthing) results support field geophysical investigations, and have led to the development of a technique for distinguishing massive ice and overburden material of the permafrost. The two‐dimensional DC resistivity sounding tomography and ground‐penetrating radar profiling are useful for ice detection under heterogeneous conditions. However, the DC resistivity sounding investigation required high‐quality ground contact and less area coverage. The active layer thickness and the homogeneous horizontal structure of the overburden material are important parameters influencing detection of massive ice in permafrost for most methods such as seismic, TEM, or surface NMR.
Landscape estimation of canopy C:N ratios under variable drought stress in Northern Great Plains rangelands
Authors: Phillips Rebecca L. , Beeri Ofer , Liebig Mark
Published: June 2006

Plant carbon/nitrogen ratio (C:N) exerts significant control over net primary production (NPP) for most biomes, yet remote quantification at ecosystem scales is often hindered by coarse spatial resolution and by the influence of variable plant water content on spectral absorption. Consequently, remote sensing–based estimates for ecosystem properties can be masked by hectare‐scale landscape patchiness and by drought stress. We approached the water content problem first by identifying those spectra sensitive to plant C:N but not sensitive to varying intensities of plant water stress under controlled conditions. Then we tested formulae developed at a plant scale with monocultures on mixed‐grass prairie field plots several times during the growing season and derived an optimum rangeland C:N formula (RCNF). The RCNF was evaluated on pastures under experimental grazing treatments using mid‐resolution, multispectral sensors. Delineation of canopy C:N within and between pastures was achieved under variable canopy moisture conditions using either Landsat 5 or ASTER spectral data. Landsat 5 canopy C:N ratios were estimated four times during the 2004 growing season with <14% error (RMSE = 3.1). Estimates tracked field measurements, with greater C:N ratios in April (between 30 and 34) and lower C:N in September (between 24 and 27). We also tested the RCNF on ASTER satellite data on experimental grazing treatments and found ASTER estimates were within 9.6% of field measurements (RSME = 1.5). Spatial and temporal variability among grazing treatments and collections times were similar to remote estimates despite variable plant moisture, indicating that rangeland C:N may be quantified using current, economical, satellite sensors within ±3 C:N units.
Ferric iron in Al‐bearing post‐perovskite
Authors: Sinmyo Ryosuke , Hirose Kei , St. C. O'Neill Hugh , Okunishi Eiji
Published: June 2006

The Fe3+/ΣFe ratios in both (Al, Fe)‐bearing MgSiO3 post‐perovskite phase and Ca‐ferrite‐type Al‐phase, synthesized in a natural mid‐oceanic ridge basalt (MORB) composition at 113 GPa and 2240 K, were determined by electron energy‐loss near‐edge structure (ELNES) spectroscopy. The results demonstrate that post‐perovskite has high proportions of Fe3+ with Fe3+/ΣFe ratio of 0.65 ± 0.04. The high Fe3+ concentration in post‐perovskite may have significant effects on its physical properties, phase stability, and iron partitioning. In contrast, the Ca‐ferrite‐type Al‐phase, which is the second Fe‐bearing phase in a subducting MORB crust, is enriched in Fe2+ rather than Fe3+ with Fe3+/ΣFe ratio of 0.15 and 0.29.
Three‐band model for noninvasive estimation of chlorophyll, carotenoids, and anthocyanin contents in higher plant leaves
Authors: Gitelson Anatoly A. , Keydan Galina P. , Merzlyak Mark N.
Published: June 2006

Leaf pigment content and composition provide important information about plant physiological status. Reflectance measurements offer a rapid, nondestructive technique to estimate pigment content. This paper describes a recently developed three‐band conceptual model capable of remotely estimating total of chlorophylls, carotenoids and anthocyanins contents in leaves from many tree and crop species. We tuned the spectral regions used in the model in accord with pigment of interest and the optical characteristics of the leaves studied, and showed that the developed technique allowed accurate estimation of total chlorophylls, carotenoids and anthocyanins, explaining more than 91%, 70% and 93% of pigment variation, respectively. This new technique shows a great potential for noninvasive tracking of the physiological status of vegetation and the impact of environmental changes.
Neural conversion of ES cells by an inductive activity on human amniotic membrane matrix
Authors: Ueno Morio , Matsumura Michiru , Watanabe Kiichi , Nakamura Takahiro , Osakada Fumitaka , Takahashi Masayo , Kawasaki Hiroshi , Kinoshita Shigeru , Sasai Yoshiki
Published: June 2006

Here we report a human-derived material with potent inductive activity that selectively converts ES cells into neural tissues. Both mouse and human ES cells efficiently differentiate into neural precursors when cultured on the matrix components of the human amniotic membrane in serum-free medium [amniotic membrane matrix-based ES cell differentiation (AMED)]. AMED-induced neural tissues have regional characteristics (brainstem) similar to those induced by coculture with mouse PA6 stromal cells [a common method called stromal cell-derived inducing activity (SDIA) culture]. Like the SDIA culture, the AMED system is applicable to the
in vitro
generation of various CNS tissues, including dopaminergic neurons, motor neurons, and retinal pigment epithelium. In contrast to the SDIA method, which uses animal cells, the AMED culture uses a noncellular inductive material derived from an easily available human tissue; therefore, AMED should provide a more suitable and versatile system for generating a variety of neural tissues for clinical applications.
Membrane protein dynamics and detergent interactions within a crystal: A simulation study of OmpA
Authors: Bond Peter J. , Faraldo-Gómez José D. , Deol Sundeep S. , Sansom Mark S. P.
Published: June 2006

Molecular dynamics (MD) simulations are used to explore the dynamics of a membrane protein in its crystal environment. A 50-ns-duration simulation (at a temperature of 300 K) is performed for the crystallographic unit cell of the bacterial outer membrane protein OmpA. The unit cell contains four protein molecules, plus detergent molecules and water. An excellent correlation between simulated and experimental values of crystallographic
B
factors is observed. Effectively, 0.2 μs of protein trajectories are obtained, allowing a critical assessment of simulation quality. Some deficiency in conformational sampling is demonstrated, but averaging over multiple trajectories improves this limitation. The previously undescribed structure and dynamics of detergent molecules in a unit cell are reported here, providing insight into the interactions important in the formation and stabilization of the crystalline environment at room temperature. In particular, we show that at room temperature the detergent molecules form a dynamic, extended micellar structure spreading over adjacent OmpA monomers within the crystal.
Two levels of interference in mouse meiotic recombination
Authors: de Boer Esther , Stam Piet , Dietrich Axel J. J. , Pastink Albert , Heyting Christa
Published: June 2006

During meiosis, homologous chromosomes (homologs) undergo recombinational interactions, which can yield crossovers (COs) or noncrossovers. COs exhibit interference; they are more evenly spaced along the chromosomes than would be expected if they were placed randomly. The protein complexes involved in recombination can be visualized as immunofluorescent foci. We have analyzed the distribution of such foci along meiotic prophase chromosomes of the mouse to find out when interference is imposed and whether interference manifests itself at a constant level during meiosis. We observed strong interference among MLH1 foci, which mark CO positions in pachytene. Additionally, we detected substantial interference well before this point, in late zygotene, among MSH4 foci, and similarly, among replication protein A (RPA) foci. MSH4 foci and RPA foci both mark interhomolog recombinational interactions, most of which do not yield COs in the mouse. Furthermore, this zygotene interference did not depend on SYCP1, which is a transverse filament protein of mouse synaptonemal complexes. Interference is thus not specific to COs but may occur in other situations in which the spatial distribution of events has to be controlled. Differences between the distributions of MSH4/RPA foci and MLH1 foci along synaptonemal complexes might suggest that CO interference occurs in two successive steps.
Shiga toxin of enterohemorrhagic
Escherichia coli
type O157:H7 promotes intestinal colonization
Authors: Robinson Cory M. , Sinclair James F. , Smith Michael J. , O’Brien Alison D.
Published: June 2006

Enterohemorrhagic
Escherichia coli
(EHEC) 0157:H7 is a food-borne pathogen that can cause bloody diarrhea and, occasionally, acute renal failure as a consequence of Shiga toxin (Stx) production by the organism. Stxs are potent cytotoxins that are lethal to animals at low doses. Thus, Stxs not only harm the host but, as reported here, also significantly enhance the capacity of EHEC O157:H7 to adhere to epithelial cells and to colonize the intestines of mice. Tissue culture experiments showed that this toxin-mediated increase in bacterial adherence correlated with an Stx-evoked increase in a eukaryotic receptor for the EHEC O157:H7 attachment factor intimin.
Phylogeography of Asian wild rice,
Oryza rufipogon
, reveals multiple independent domestications of cultivated rice,
Oryza sativa
Authors: Londo Jason P. , Chiang Yu-Chung , Hung Kuo-Hsiang , Chiang Tzen-Yuh , Schaal Barbara A.
Published: June 2006

Cultivated rice,
Oryza sativa
L., represents the world’s most important staple food crop, feeding more than half of the human population. Despite this essential role in world agriculture, the history of cultivated rice’s domestication from its wild ancestor,
Oryza rufipogon
, remains unclear. In this study, DNA sequence variation in three gene regions is examined in a phylogeographic approach to investigate the domestication of cultivated rice. Results indicate that India and Indochina may represent the ancestral center of diversity for
O. rufipogon
. Additionally, the data suggest that cultivated rice was domesticated at least twice from different
O. rufipogon
populations and that the products of these two independent domestication events are the two major rice varieties,
Oryza sativa indica
and
Oryza sativa japonica
. Based on this geographical analysis,
O. sativa indica
was domesticated within a region south of the Himalaya mountain range, likely eastern India, Myanmar, and Thailand, whereas
O. sativa japonica
was domesticated from wild rice in southern China.
Knockin mice expressing fluorescent δ-opioid receptors uncover G protein-coupled receptor dynamicsinvivo
Authors: Scherrer Grégory , Tryoen-Tóth Petra , Filliol Dominique , Matifas Audrey , Laustriat Delphine , Cao Yu Q. , Basbaum Allan I. , Dierich Andrée , Vonesh Jean-Luc , Gavériaux-Ruff Claire , Kieffer Brigitte L.
Published: June 2006

The combination of fluorescent genetically encoded proteins with mouse engineering provides a fascinating means to study dynamic biological processes in mammals. At present, green fluorescent protein (GFP) mice were mainly developed to study gene expression patterns or cell morphology and migration. Here we used enhanced GFP (EGFP) to achieve functional imaging of a G protein-coupled receptor (GPCR)in vivo. We created mice where the δ-opioid receptor (DOR) is replaced by an active DOR-EGFP fusion. Confocal imaging revealed detailed receptor neuroanatomy throughout the nervous system of knockin mice. Real-time imaging in primary neurons allowed dynamic visualization of drug-induced receptor trafficking. In DOR-EGFP animals, drug treatment triggered receptor endocytosis that correlated with the behavioral response. Mice with internalized receptors were insensitive to subsequent agonist administration, providing evidence that receptor sequestration limits drug efficacyin vivo. Direct receptor visualization in mice is a unique approach to receptor biology and drug design.
Extracellular signal-regulated kinase (ERK) 5 is necessary and sufficient to specify cortical neuronal fate
Authors: Liu Lidong , Cundiff Paige , Abel Glen , Wang Yupeng , Faigle Roland , Sakagami Hiroyuki , Xu Mei , Xia Zhengui
Published: June 2006

Multipotent cortical progenitor cells differentiate into neurons and glial cells during development; however, mechanisms governing the specification of progenitors to a neuronal fate are not well understood. Although both extrinsic and intrinsic factors regulate this process, little is known about kinase signaling mechanisms that direct neuronal fate. Here, we report that extracellular signal-regulated kinase (ERK) 5 is expressed and active in proliferating cortical progenitors. Lentiviral gene delivery of a dominant negative ERK5 or dominant negative MAP kinase kinase 5 reduced the number of neurons generated from rat cortical progenitor cells in culture, whereas constitutive activation of ERK5 increased the production of neurons. Furthermore, when cortical progenitor cells were treated with ciliary neurotrophic factor, which induces precocious glial differentiation, ERK5 activation still promoted neuronal fate while suppressing glial differentiation. Our data also indicate that ERK5 does not directly regulate proliferation or apoptosis of cultured cortical progenitors. We conclude that ERK5 is necessary and sufficient to stimulate the generation of neurons from cortical progenitors. These results suggest a previously uncharacterized function for ERK5 signaling during brain development and raise the interesting possibility that extrinsic factors may instruct cortical progenitors to become neurons by activating the ERK5 pathway.
Nucleophosmin/anaplastic lymphoma kinase (NPM/ALK) oncoprotein induces the T regulatory cell phenotype by activating STAT3
Authors: Kasprzycka Monika , Marzec Michal , Liu Xiaobin , Zhang Qian , Wasik Mariusz A.
Published: June 2006

The mechanisms of malignant cell transformation mediated by the oncogenic, chimeric nucleophosmin/anaplastic lymphoma kinase (NPM/ALK) tyrosine kinase remain only partially understood. Here we report that the NPM/ALK-carrying T cell lymphoma (ALK+TCL) cells secrete IL-10 and TGF-β and express FoxP3, indicating their T regulatory (Treg) cell phenotype. The secreted IL-10 suppresses proliferation of normal immune, CD3/CD28-stimulated peripheral blood mononuclear cells and enhances viability of the ALK+TCL cells. The Treg phenotype of the affected cells is strictly dependent on NPM/ALK expression and function as demonstrated by transfection of the kinase into BaF3 cells and inhibition of its enzymatic activity and expression in ALK+TCL cells. NPM/ALK, in turn, induces the phenotype through activation of its key signal transmitter, signal transducer and activator of transcription 3 (STAT3). These findings identify a mechanism of NPM/ALK-mediated oncogenesis based on induction of the Treg phenotype of the transformed CD4+T cells. These results also provide an additional rationale to therapeutically target the chimeric kinase and/or STAT3 in ALK+TCL.
Leishmania
β-1,2-mannan is assembled on a mannose-cyclic phosphate primer
Authors: Sernee M. Fleur , Ralton Julie E. , Dinev Zoran , Khairallah George N. , O’Hair Richard A. , Williams Spencer J. , McConville Malcolm J.
Published: June 2006

Infective stages of the protozoan parasite
Leishmania
spp. accumulate a class of β-1,2-mannan oligosaccharides as their major carbohydrate reserve material. Here, we describe the biosynthesis of
Leishmania
mannan. Mannan precursors were identified by metabolic labeling of
Leishmania mexicana
promastigotes with [
3
H]mannose. Label was initially incorporated into a phosphomannose primer and short phosphorylated β-1,2-mannan oligomers that were two to five residues long. Analysis of the mannan primer by Fourier transform ion-cyclotron resonance MS and various enzymatic and chemical treatments and comparison with authentic mannose (Man) phosphates indicated the presence of Man-α-1,4-cyclic phosphate. This primer was synthesized from Man-6-phosphate by means of Man-1-phosphate in a cell-free system. Short mannan chains containing the primer were subsequently dephosphorylated and then further elongated by GDP-Man-dependent transferases
in vivo
and in the cell-free system. The synthesis of this glycan primer likely constitutes a key regulatory step in mannan biosynthesis and is a potential target for antileishmanial drugs.
Creditor Initiatives in the 1980s and 1990s
Authors: Roodman David
Published: June 2006

This chapter presents an overview of the sovereign-debt initiatives from the last twenty-five years. It examines the programs devised by creditors, namely the World Bank and IMF, during the 1980s and 1990s, that aimed at addressing the mounting problem of developing-country debt. The “austerity” lending of the 1980s and the structural adjustment programs of the 1990s are discussed, and the inherent failings that characterized those efforts, including reduced public investment which has led to economic stagnation, are criticized.
Sovereign Debt and the Debt Crisis in Emerging Countries: The Experience of the 1990s
Authors: Marx Daniel , Echague Jose , Sandleris Guido
Published: June 2006

This chapter analyzes the main problems of the current global sovereign debt markets, particularly in relation to emerging countries, and presents some policy recommendations. It describes the evolution of sovereign debt markets during the 1990s. It then focuses on the emerging countries' debt crises of the late 1990s and their resolution. Finally, drawing from the analysis of the previous sections, it argues that there is room for significant improvements in the architecture of sovereign debt markets and that emerging countries have much to do in terms of unilateral reforms.
Defining “Illegitimate Debt”: When Creditors Should Be Liable for Improper Loans
Authors: Hanlon Joseph
Published: June 2006

This chapter addresses the questions: why should poor countries be expected to repay the debts imposed upon them by unelected and repressive governments? Who should shoulder the burden of repaying the billions of dollars stolen by the likes of Mobutu, Marcos, and Saddam Hussein? How can creditors expect South Africans to pay for loans taken out during the apartheid regime and at that time used as a means of oppression? It argues that loans to certain borrowers or for certain purposes are prima facie illegitimate. This category includes loans to dictators, odious debt (debt used for repression), and extortionate loans. Second, certain types of behavior by lenders can also make a loan illegitimate: usury, money laundering, and gross negligence in lending. When these conditions are met, responsibility for repayment cannot be properly placed on the borrower.
The Legal Case for Debt Repudiation
Authors: Jochnick Chris
Published: June 2006

This chapter briefly describes the tremendous social and economic costs of overindebtedness and the role of Northern creditors and governments in solving debt problems. It then sets forth legal reasons for the need for debt repudiation and/or relief: (1) the heightened level of responsibility of creditors and Northern governments; (2) violations of human rights, and (3) the illegitimacy of debt. These arguments are based on well-established principles of domestic and international law that are applicable to domestic proceedings and relevant to a future international insolvency mechanism. The arguments serve to challenge popular or political understandings of the legal sanctity of debt, thereby creating space and support for more ambitious solutions to debt crises.
Ethics, Market and Government Failure, and Globalization: Perspectives on Debt and Finance
Authors: Stiglitz J. E.
Published: June 2006

This chapter looks at the ethical aspects of globalization during the 1990s. It argues that in the way that they have sought to shape globalization, the advanced industrial countries and some of the multilateral institutions that they control have violated some basic ethical norms. Three central issues in the context of global finance are analyzed: the design of debt contracts between developed and developing countries and other aspects of lending behavior; the consequences of excessive debt; and broader issues associated with the global reserve system. Three types of ethical problems are discussed: (1) where markets (or international institutions) take advantage of their “power” and the weaknesses of the developing country to pursue their own interests at the expense of or risk to those in the developing countries; (2) where international financial institutions provide advice that works to the disadvantage of the developing countries; and (3) where the markets, and especially the international financial institutions, have not done as much as they could for the well-being of the developed countries.
Helping the Poor to Help Themselves: Debt Relief or Aid?
Authors: Arslanalp Serkan , Henry Peter Blair
Published: June 2006

This chapter discusses the central economic question of debt relief: does debt relief work to promote economic growth? This seemingly straightforward question — often taken for granted by debt campaigners — merits closer attention to ensure that relief bears constructive and sustainable outcomes. It is argued that debt relief is highly effective at promoting growth in countries suffering from a “debt overhang”, where reducing debt levels will stimulate investment and net resource transfers from abroad, but less effective in countries where infrastructure is weak and where net resource transfers are already positive.
Odious Debt
Authors: Jayachandran Seema , Kremer Michael
Published: June 2006

This chapter discusses the problem of illegitimate debt from a new angle. Instead of focusing on borrowers, it focuses on the role and incentives of creditors who lend to questionable governments for illicit purposes. This approach follows a theme that runs throughout the book: responsibility for bad loans should lie with lenders as much as borrowers. It is argued that as long as borrowing countries are obligated to repay bad debts, lenders will have no incentive to avoid bad loans. Furthermore, once a loan is made to an odious regime, no tribunal can be entrusted to label it as such, and charges of favoritism will always be made against the tribuna's decision.
Dealing Comprehensively, and Justly, with Sovereign Debt
Authors: Boorman Jack
Published: June 2006

This chapter discusses ideas for resolving debt crises. It argues that a narrow focus on debt relief in HIPCs is insufficient and that the activist community and lenders must look to finding broader measures of foreign aid and creating a fair trading environment. In the end, finding the “right” level of debt relief is impossible and ignores the more important aim of delivering a better life to impoverished people. Support is given to a proposal floated by the IMF for a sovereign debt restructuring mechanism (SDRM) to resolve pending debt crises in developing countries.
The IMF's SDRM—Simply Disastrous Rescheduling Management?
Authors: Raffer Kunibert
Published: June 2006

This chapter argues that that the IMF's sovereign debt restructuring mechanism (SDRM) is misguided in several ways. Most importantly, the SDRM proposal leaves the IMF itself in the position of having to make two crucial decisions: whether to endorse a stay of payments to creditors, and what amount of debt is “sustainable”, i.e., how much debt should be written off. This decision-making capacity creates a conflict of interest, as the IMF itself is almost always a creditor to countries experiencing debt crises. As an alternative to the IMF's SDRM, a mechanism modeled on Chapter 9 of the US bankruptcy code is proposed, which applies to municipalities and resolves some of the knotty problems of dealing with public (as compared with private) insolvency. This approach would rely on ad hoc panels formed by the debtor and creditor committees and therefore would not require that the IMF serve as arbitrator.
The Jubilee 2000 Campaign: A Brief Overview
Authors: Pettifor Ann
Published: June 2006

This chapter describes what is perhaps the most powerful innovation for achieving debt relief for the poor since the mid-1990s: the mobilization of civil societies. The Jubilee 2000 movement was extraordinary — uniting tens of millions of people and spanning nations and continents — all in the name of reducing the burden of developing-country debt. The movement's history and analysis of its successes and failures underscores the importance of civil society groups in the debate over debt and their potential role in promoting and implementing solutions.
Exceeding Our Grasp
Authors: Stanford P. Kyle
Published: June 2006

The incredible achievements of modern scientific theories lead most of us to embrace scientific realism: the view that our best theories offer us at least roughly accurate descriptions of otherwise inaccessible parts of the world like genes, atoms, and the big bang. This book argues that careful attention to the history of scientific investigation invites a challenge to this view that is not well represented in contemporary debates about the nature of the scientific enterprise. The historical record of scientific inquiry, the book suggests, is characterized by the problem of unconceived alternatives. Past scientists have routinely failed even to conceive of alternatives to their own theories and lines of theoretical investigation, alternatives that were both well-confirmed by the evidence available at the time and sufficiently serious as to be ultimately accepted by later scientific communities. The book supports this claim with a detailed investigation of the mid-to-late 19th-century theories of inheritance and generation proposed in turn by Charles Darwin, Francis Galton, and August Weismann. It goes on to argue that this historical pattern strongly suggests that there are equally well-confirmed and scientifically serious alternatives to our own best theories that remain currently unconceived. Moreover, this challenge is more serious than those rooted in either the so-called pessimistic induction or the underdetermination of theories by evidence, in part because existing realist responses to these latter challenges offer no relief from the problem of unconceived alternatives itself.
Realism, Pessimism, and Underdetermination
Authors: Stanford P. Kyle
Published: June 2006

This chapter begins with a discussion of scientific realism. It then looks at some reasons that have been given for doubting that the pessimistic induction and the underdetermination of theories by evidence really should lead us to withhold belief in the claims of the best scientific theories. It is argued that the most powerful challenge to scientific realism has yet to be formulated, but emerges naturally from a systematic consideration of the reasons that the much more famous challenges offered by the pessimistic induction, and that the underdetermination of theories by evidence have left scientific realists unconvinced of their significance.