Greater Loss (greater + loss)

Distribution by Scientific Domains


Selected Abstracts


Microstructural status of ipsilesional and contralesional corticospinal tract correlates with motor skill in chronic stroke patients

HUMAN BRAIN MAPPING, Issue 11 2009
Judith D. Schaechter
Abstract Greater loss in structural integrity of the ipsilesional corticospinal tract (CST) is associated with poorer motor outcome in patients with hemiparetic stroke. Animal models of stroke have demonstrated that structural remodeling of white matter in the ipsilesional and contralesional hemispheres is associated with improved motor recovery. Accordingly, motor recovery in patients with stroke may relate to the relative strength of CST degeneration and remodeling. This study examined the relationship between microstructural status of brain white matter tracts, indexed by the fractional anisotropy (FA) metric derived from diffusion tensor imaging (DTI) data, and motor skill of the stroke-affected hand in patients with chronic stroke. Voxelwise analysis revealed that motor skill significantly and positively correlated with FA of the ipsilesional and contralesional CST in the patients. Additional voxelwise analyses showed that patients with poorer motor skill had reduced FA of bilateral CST compared to normal control subjects, whereas patients with better motor skill had elevated FA of bilateral CST compared to controls. These findings were confirmed using a DTI-tractography method applied to the CST in both hemispheres. The results of this study suggest that the level of motor skill recovery achieved in patients with hemiparetic stroke relates to microstructural status of the CST in both the ipsilesional and contralesional hemispheres, which may reflect the net effect of degeneration and remodeling of bilateral CST. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source]


Costs of Refuge Use Affect Escape Decisions of Iberian Rock Lizards Lacerta monticola

ETHOLOGY, Issue 6 2000
José Martín
Theoretical models of anti-predator escape behaviour suggest that prey may adjust their escape response such that the optimal flight distance is the point at which the costs of staying exceed the costs of fleeing. Anti-predatory decisions should be made based also on consequences for long-term expected fitness, such as the costs of refuge use. For example, in lizards, the maintenance of an optimal body temperature is essential to maximize physiological processes. However, if unfavourable thermal conditions of refuges can decrease the body temperature of lizards, their escape decision should be influenced by refuge conditions. Analyses of the variation in flight distances and emergence latency from a refuge for the lizard Lacerta monticola under two different predation risk levels, and their relationship with the thermal environment, supported these predictions. When risk increased, lizards had longer emergence latencies, and thus costs of refuge use increased (a greater loss of time and body temperature). In the low-risk situation, lizards that were farther from the refuge had longer flight distances, whereas thermal conditions were less important. When risk increased, lizards had longer flight distances when refuges were farther off, but also when the external heating rate and the refuge cooling rate were lower. The results suggest that, in addition to the risk of predation, expected long-term fitness costs of refuges can also affect escape decisions. [source]


A modified MPTP treatment regime produces reproducible partial nigrostriatal lesions in common marmosets

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2005
Mahmoud M. Iravani
Abstract Standard MPTP treatment regimens in primates result in >,85% destruction of nigral dopaminergic neurons and the onset of marked motor deficits that respond to known symptomatic treatments for Parkinson's disease (PD). The extent of nigral degeneration reflects the late stages of PD rather than events occurring at its onset. We report on a modified MPTP treatment regimen that causes nigral dopaminergic degeneration in common marmosets equivalent to that occurring at the time of initiation of motor symptoms in man. Subcutaneous administration of MPTP 1 mg/kg for 3 consecutive days caused a reproducible 60% loss of nigral tyrosine hydroxylase (TH)-positive cells, which occurred mainly in the calbindin-D28k -poor nigrosomes with a similar loss of TH-immunoreactivity (TH-ir) in the caudate nucleus and the putamen. The animals showed obvious motor abnormalities with reduced bursts of activity and the onset of motor disability. However, the loss of striatal terminals did not reflect early PD because a greater loss of TH-ir occurred in the caudate nucleus than in the putamen and a marked reduction in TH-ir occurred in striatal patches compared to the matrix. Examination of striatal fibres following a partial MPTP lesion showed a conspicuous increase in the number and the diameter of large branching fibres in the putaminal and to some extent caudatal matrix, pointing to a possible compensatory sprouting of dopaminergic terminals. In addition, these partially lesioned animals did not respond to acute treatment with L-DOPA. This primate partial lesions model may be useful for examining potential neuroprotective or neurorestorative agents for PD. [source]


Treatment of cellulite with LPG endermologie

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2009
A. Tülin Güleç MD
Background, LPG endermologie is a FDA-approved massage system in use worldwide for cellulite treatment that lacks clinical study. Objective, To determine the efficacy and safety of LPG endermologie in treating cellulite. Methods, Thirty-three healthy women (cellulite grades, 1,3 based on the 4-stage Nurnberger,Muller scale) had LPG treatments twice weekly for a total of 15 sessions. Clinical evaluation was performed by digital photography for cellulite grade assessment, and perimetric measurements of eight body sites for the evaluation of body contours. Results, Significant differences were found regarding mean cellulite grades before and after treatment. However, improved cellulite appearance occurred in only 5 women (15%). All patients showed a significant circumference loss at every measured body site. Weight losers had significantly greater loss of total and average body circumference than weight gainers. Limitations, Relatively small sample size and lack of more-objective methods for assessing treatment success. Conclusion, LPG endermologie is a well-tolerated and effective method for reducing the diameter of body circumference, however, it is mildly effective in reducing the cellulite grade and so, improving its orange-peel appearance. [source]


Block-based fine granularity scalable video coding with optimized rate allocation for content-aware streaming

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2003
Yuwen He
Abstract This article proposes a novel block-based fine granularity scalable (FGS) video coding structure with optimized rate allocation for content-aware streaming, which is more flexible than MPEG-4 FGS specified in the streaming profile of MPEG-4 standard (IS-14496). In MPEG-4 FGS streaming, rate allocation can only be based on frame because MBs' compressed data are interlaced between bit-planes. However in the proposed coding structure, every MB's data are independent; therefore, streaming server can allocate bits according to content's importance, and the quality of those regions of interest is enhanced selectively with more bits allocated. In this way, the streaming server can have a differentiated delivery strategy to support a personalized streaming service considering user's preference. But the uniform rate allocation of proposed block-based FGS coding will result in a greater loss of coding efficiency than that of MPEG-4 FGS within a quite wide bit-rate range. An optimized and fast rate allocation method according to block's rate-distortion is proposed to solve this critical issue. And the coding efficiency is improved successfully, which can be comparable with MPEG-4 FGS coding and is even better up to 0.5 dB, with some sequences at medium bit-rates. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 322,330, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10066 [source]


Kidney Function as a Predictor of Loss of Lean Mass in Older Adults: Health, Aging and Body Composition Study

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 10 2007
Linda F. Fried MD
OBJECTIVES: To assess the association between kidney function and change in body composition in older individuals. DESIGN: Prospective cohort study. SETTING: Two sites, Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand twenty-six well-functioning, participants aged 70 to 79 in the Health, Aging and Body Composition Study. MEASUREMENTS: Body composition (bone-free lean mass and fat mass) was measured using dual x-ray absorptiometry annually for 4 years. Kidney function was measured at baseline according to serum creatinine (SCr). Comorbidity and inflammatory markers were evaluated as covariates in mixed-model, repeated-measures analysis. RESULTS: High SCr was associated with loss of lean mass in men but not women, with a stronger relationship in black men (P=.02 for difference between slopes for white and black men). In white men, after adjustment for age and comorbidity, higher SCr remained associated with loss of lean mass (,0.07±0.03 kg/y greater loss per 0.4 mg/dL (1 standard deviation (SD)), P=.009) but was attenuated after adjustment for inflammatory factors (,0.05±0.03 kg/y greater loss per SD, P=.10). In black men, the relationship between SCr and loss of lean mass (,0.19±0.04 kg/y per SD, P<.001) persisted after adjustment for inflammation and overall weight change. CONCLUSION: Impaired kidney function may contribute to loss of lean mass in older men. Inflammation appeared to mediate the relationship in white but not black men. Future studies should strive to elucidate mechanisms linking kidney disease and muscle loss and identify treatments to minimize loss of lean mass and its functional consequences. [source]


THE EFFECT OF ENZYMATIC MASH TREATMENT, PRESSING, CENTRIFUGATION, HOMOGENIZATION, DEAERATION, STERILIZATION AND STORAGE ON CARROT JUICE

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2007
HONGMEI LIAO
ABSTRACT The enzyme preparation Pectinex Smash XXL was employed to macerate the carrot pulp, the effect of enzymatic mash treatment (EMT), pressing, centrifugation, homogenization, deaeration, sterilization and storage on carrot juice was investigated. As compared with the control sample, an increase of juice yield, total soluble solid (TSS) and carotenoids in carrot juice was close to 20%, 1% and 26 mg/kg, respectively, after EMT. The EMT also increased the color parameters CIEL*, a*and C*values in carrot juice. However, it significantly decreased the viscosity from 2.54 to 2.09 mPa·s. The centrifugation resulted in a significant decline in turbidity from 240.33 to 187.33 NTU and a significant increase in the color parameters in carrot juice. After homogenization, the turbidity and the carotenoids in carrot juice were significantly reduced from 187.33 to 161.67 NTU and from 61.87 to 58.76 mg/kg, respectively. The turbidity and carotenoids in carrot juice decreased during storage, and all the color parameters had a closer relationship with storage temperature and time; higher storage temperature and longer storage time caused greater loss of color. [source]


Influence of Exposure to Light on the Sensorial Quality of Minimally Processed Cauliflower

JOURNAL OF FOOD SCIENCE, Issue 1 2007
Susana Sanz Cervera
ABSTRACT:, The impact of lighting on minimally processed cauliflower packaged in 4 different film types (PVC and 3 P-Plus) has been measured and quantified. The effect on the sensorial quality of storage at 4 °C in darkness and partial or continuous lighting was evaluated. The gas concentrations in the packages and the weight losses were also determined. Atmosphere composition inside the packages depended on both the permeability of the film used for the packaging and exposure to light. Samples stored with lighting maintained the gaseous exchange between plant tissue and the atmosphere inside the packages for longer periods than in samples kept in darkness. This prompted a greater loss of water vapor as well as the development of atmospheres with low levels of O2 and high levels of CO2 in the samples packed with less permeable films. The most important aspect in sensory evaluation was color. In instrumental color evaluation, coordinates h* and L* were the main means for estimating color evolution. The presence of light accelerated browning in the cut zones. The development of abnormal coloring in these areas marked the end of shelf life for minimally processed cauliflower. Among the sensory attributes studied, color was the most affected by exposure to light. Samples packed in P-Plus 120 film displayed the lowest level of color deterioration in the cut zones. However, under lit conditions, the low permeability of this film caused atmospheres with very low O2 contents and high CO2 contents. These atmospheres produced a loss of texture and the development of off-odors. [source]


Clinical Trial: High-dose furosemide plus small-volume hypertonic saline solutions vs. repeated paracentesis as treatment of refractory ascites

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2009
G. LICATA
Summary Background, In patients with cirrhosis, ascites is defined as refractory when it cannot be mobilized or recurs early in standard diuretic therapy. Aim, To compare the safety and efficacy of intravenous high-dose furosemide + hypertonic saline solutions (HSS) with repeated paracentesis in patients with cirrhosis and refractory ascites. Patients and methods, Eighty-four subjects (59/25 M/F) with cirrhosis, mostly of viral aetiology, admitted for refractory ascites, were randomly assigned to receive furosemide (250,1000 mg/bid i.v.) plus HSS (150 mL H2O with NaCl 1.4,4.6% or 239,187 mEq/L) (60 patients, Group A) or to repeated paracentesis and a standard diuretic schedule (24 patients, Group B). Results, During hospitalization, Group A patients had more diuresis (1605 ± 131 mL vs. 532 ± 124 mL than Group B patients; P < 0.001) and a greater loss of weight at discharge (,8.8 ± 4.8 kg vs. ,4.5 ± 3.8 kg, P < 0.00). Control of ascites, pleural effusions and/or leg oedema was deemed significantly better in Group A. Conclusions, This randomized pilot study suggests that HHS plus high-dose furosemide is a safe and effective alternative to repeated paracentesis when treating hospitalized patients with cirrhosis and refractory ascites. Larger studies will be needed to evaluate long-term outcomes such as readmission and mortality. [source]


The role of loss of meaning in the pursuit of treatment for posttraumatic stress disorder

JOURNAL OF TRAUMATIC STRESS, Issue 2 2005
Alan Fontana
Clinical observation and theory suggest that people who have difficulty coping with their exposure to traumatic events often experience a loss of meaning to their lives. This article examines the contribution of loss of meaning to seeking help from clergy and/or mental health providers. Results support the hypotheses that veterans who have suffered a greater loss of meaning are more likely to seek help from clergy and from VA mental health professionals. We suggest that veterans who seek help from clergy are particularly desirous of achieving a restoration of meaning that is specific to their loss, and that this quest sustains a continued pursuit of mental health treatment, especially among those who seek help from the VA. [source]


Proliferative and apoptotic differences between alveolar rhabdomyosarcoma subtypes: A comparative study of tumors containing PAX3-FKHR or PAX7-FKHR gene fusions

PEDIATRIC BLOOD & CANCER, Issue 2 2001
Margaret H. Collins MD
Abstract Background Most alveolar rhabdomyosarcomas (ARMS) have chromosome translocations and resultant gene fusion products. The more common translocation fuses the PAX3 and FKHR genes; patients who have PAX3-FKHR-positive ARMS have reduced event-free survival compared to patients with ARMS containing the less common translocation that fuses the PAX7 and FKHR genes. Procedure We examined histology, immunohistochemical markers of differentiation, and cell cycle characteristics of a panel of ARMS containing either PAX3-FKHR or PAX7-FKHR transcript to determine if these features differ between the ARMS subsets. Results Cell cycle parameters varied significantly: the number of nuclei that stained with either an immunohistochemical marker of proliferation (MIB1), or a TUNEL-based assay for apoptosis was significantly greater in tumors that expressed PAX3-FKHR compared to tumors that expressed PAX7-FKHR transcript. Conclusions We conclude that compared to PAX7-FKHR-containing tumors, ARMS that contain PAX3-FKHR transcript have (1) increased cell proliferation, consistent with greater loss of cell cycle regulation, and (2) apoptosis that is increased but insufficient to prevent tumor formation. More marked cell cycle dysregulation may contribute to poorer prognosis for patients with ARMS that have PAX3-FKHR fusion. Med Pediatr Oncol 2001;37:83,89. © 2001 Wiley-Liss, Inc. [source]


Latest news and product developments

PRESCRIBER, Issue 7 2008
Article first published online: 28 APR 200
Referrals from Boots The majority of people requesting Boots' erectile dysfunction or weight management programmes are referred to their GP(Pharm J 2008;280:297). The programmes are run under patient group directions and exclude people with elevated blood pressure, blood glucose or cholesterol. Over 80 per cent of customers screened for the erectile dysfunction programme in Manchester and two-thirds of those screened for the national obesity programme were referred. Vildagliptin: new DPP-4 inhibitor for diabetes Novartis has introduced the DPP-4 inhibitor vildagliptin for the treatment of type 2 diabetes. Two formulations are available: Galvus (vildagliptin 50mg) is licensed for use with metformin, a sulphonylurea or a thiazolidinedione when these agents do not achieve glycaemic control alone, and Eucreas (vildagliptin 50mg plus metformin 850 or 1000mg) is licensed for patients requiring combined therapy with vildagliptin and metformin. Inhibition of DPP-4 blocks the breakdown of the incretin hormones GIP and GLP-1, reducing fasting plasma glucose and postprandial hyperglycaemia. Vildagliptin is the second DPP-4 inhibitor to be introduced; the first was sitagliptin (Januvia), which has similar licensed indications. The third available drug acting on the incretin system is the incretinmimetic exenatide (Byetta); administered by injection, this is licensed for use with metformin and/or a sulphonylurea and is the only agent in this class to be approved for triple therapy. No comparative trials of these agents have been published. A month's treatment with twice-daily vildagliptin 50mg or either strength of vildagliptin plus metformin costs £31.76. Sitagliptin 100mg once daily costs £33.26. Sinusitis symptoms don't guide treatment The severity and duration of symptoms do not help to identify which patients with sinusitis will be helped by antibiotics, a new meta-analysis suggests (Lancet 2008;371: 908-14). The analysis of patient-level data from nine trials involving a total of 2547 adults showed that the number needed to treat (NNT) to cure one patient with rhinosinusitis was 15. Cure took longer to achieve in older patients and in those reporting symptoms for longer or with more severe symptoms. The authors comment that treatment is not justified given the risk of resistance and adverse effects and cost of antibiotics. Draft guidance from the National Institute for Health and Clinical Excellence (NICE) on the management of respiratory infections states that no antibiotic therapy or a delayed antibiotic prescribing strategy should be negotiated for patients with acute sinusitis. Taking cod liver oil leads to fewer NSAIDs Cod liver oil could help some patients with rheumatoid arthritis to reduce their NSAID consumption, according to a study from Dundee (Rheumatology online: 24 March 2008; doi: 10.1093/rheumatology/ ken024). A total of 97 patients were randomised to nine months' treatment with cod liver oil 10g per day or placebo. After 12 weeks, patients attempted to reduce or stop their use of NSAIDs. Significantly more of those taking cod liver oil achieved at least a 30 per cent reduction in NSAID use compared with placebo (39 vs 10 per cent). There were no differences in adverse effects or disease activity. Welsh prescriptions up The reduction in the prescription charge in Wales in 2004 was followed by an increase in prescribing of nonsedating antihistamines in wealthier areas, a study suggests (Health Policy online: 5 March 2008; doi:10.1016/j. healthpol.2008.01.006). In the two years preceding the cut, prescriptions for nonsedating antihistamines increased by about 7 per cent; in the two years after the cut, the increase was nearly 14 per cent. By contrast, there was no change in the rate of increase in the south-east of England (4,5 per cent in both periods). The increased growth in prescribing was statistically significant in the five least deprived but not in the five most deprived health boards in Wales. Aspirin linked with reduced asthma risk Low-dose aspirin is associated with a reduced risk of developing asthma, a new analysis of the Women's Health Study has shown (Thorax online: 13 March 2008; doi:10.1136/ thx.2007.091447). The analysis included 37 270 women with no asthma at baseline who were randomised to take placebo or aspirin 100mg every other day. After 10 years, 872 cases of asthma occurred in women taking aspirin and 963 with placebo, a 10 per cent reduction in risk. However, risk was not reduced in obese women. The mechanism by which aspirin may affect the risk of asthma is unknown. The latest evidence is consistent with findings published by the same investigators after analysis of two other large observational studies, the Physicians' Health Study and the Nurses Health Study. Anastrozole bone loss Long-term follow-up of the ATAC (Anastrozole, Tamoxifen, Alone or in Combination) trial has confirmed that adjuvant therapy with anastrozole (Arimidex) is associated with greater loss of bone mineral density (BMD) than tamoxifen in postmenopausal women with invasive primary breast cancer (J Clin Oncol 2008;26: 1051,7). After five years, median BMD was reduced by 6 and 7 per cent in the lumbar spine and hip with anastrozole compared with approximately 3 and 1 per cent respectively for tamoxifen, though no patients developed osteoporosis. Copyright © 2008 Wiley Interface Ltd [source]


Transplant Survivorship of Bryophyte Soil Crusts in the Mojave Desert

RESTORATION ECOLOGY, Issue 2 2010
Christina Cole
Patches of the dominant biological soil crust moss (Syntrichia caninervis) in the Mojave Desert were subjected to transplant experiments to test the survivability of crustal transplantation due to source or destination microhabitat. After a period of 27 months, all the reciprocally transplanted and replanted sections had survived. However, percent cover of the reciprocally transplanted patches declined 20,50% relative to initial cover compared to a decline in cover of 36,52% for the replanted patches. Similarly, shoot density declined an average of 26% in the transplants and replants. Shoot mortality was essentially negligible through the first 21 months of the study and then declining across all treatments to approximately 5,10 dead shoots/cm2. However, this shoot death was also observed in equivalent densities in the host patches, indicative of a community-wide decline in plant health that was probably related to a regional rainfall deficit over this period. A tendency existed for plants moved from a shaded site to have reduced shoot density in the new site, and plants moved into exposed sites lost significantly more cover than plants moved into shaded sites. These seemingly conflicting trends result from one of the transplant treatments, the shaded to exposed, exhibiting a greater loss in shoot density and decline in cover than its reciprocal transplant, exposed to shaded. For soil restoration of disturbed bryophyte crusts, we recommend using as source material both the exposed and the shaded portions of the crust but avoiding moving Syntrichia from a shaded site into an exposed site. [source]


Ratio Estimation with Measurement Error in the Auxiliary Variate

BIOMETRICS, Issue 2 2009
Timothy G. Gregoire
Summary With auxiliary information that is well correlated with the primary variable of interest, ratio estimation of the finite population total may be much more efficient than alternative estimators that do not make use of the auxiliary variate. The well-known properties of ratio estimators are perturbed when the auxiliary variate is measured with error. In this contribution we examine the effect of measurement error in the auxiliary variate on the design-based statistical properties of three common ratio estimators. We examine the case of systematic measurement error as well as measurement error that varies according to a fixed distribution. Aside from presenting expressions for the bias and variance of these estimators when they are contaminated with measurement error we provide numerical results based on a specific population. Under systematic measurement error, the biasing effect is asymmetric around zero, and precision may be improved or degraded depending on the magnitude of the error. Under variable measurement error, bias of the conventional ratio-of-means estimator increased slightly with increasing error dispersion, but far less than the increased bias of the conventional mean-of-ratios estimator. In similar fashion, the variance of the mean-of-ratios estimator incurs a greater loss of precision with increasing error dispersion compared with the other estimators we examine. Overall, the ratio-of-means estimator appears to be remarkably resistant to the effects of measurement error in the auxiliary variate. [source]


Trichloroethene and cis -1,2-dichloroethene concentration-dependent toxicity model simulates anaerobic dechlorination at high concentrations: I. batch-fed reactors

BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2010
Andrew R. Sabalowsky
Abstract A model was developed to describe toxicity from high concentrations of chlorinated aliphatic hydrocarbons (CAHs) on reductively dechlorinating cultures under batch-growth conditions. A reductively dechlorinating anaerobic Evanite subculture (EV-cDCE) was fed trichloroethene (TCE) and excess electron donor to accumulate cis -1,2-dichloroethene (cDCE) in batch-fed reactors. A second Point Mugu (PM) culture was also studied in the cDCE accumulating batch-fed experiment, as well as in a time- and concentration-dependent cDCE exposure experiment. Both cultures accumulated cDCE to concentrations ranging from 9,000 to 12,000,µM before cDCE production from TCE ceased. Exposure to approximately 3,000 and 6,000,µM cDCE concentrations for 5 days during continuous TCE dechlorination exhibited greater loss in activity proportional to both time and concentration of exposure than simple endogenous decay. Various inhibition models were analyzed for the two cultures, including the previously proposed Haldane inhibition model and a maximum threshold inhibition model, but neither adequately fit all experimental observations. A concentration-dependent toxicity model is proposed, which simulated all the experimental observations well. The toxicity model incorporates CAH toxicity terms that directly increase the cell decay coefficient in proportion with CAH concentrations. We also consider previously proposed models relating toxicity to partitioning in the cell wall (KM/B), proportional to octanol,water partitioning (KOW) coefficients. A reanalysis of previously reported modeling of batch tests using the Haldane model of Yu and Semprini, could be fit equally well using the toxicity model presented here, combined with toxicity proportioned to cell wall partitioning. A companion paper extends the experimental analysis and our modeling approach to a completely mixed reactor and a fixed film reactor. Biotechnol. Bioeng. 2010;107: 529,539. © 2010 Wiley Periodicals, Inc. [source]


Adaptive advantages of myrmecochory: the predator-avoidance hypothesis tested over a wide geographic range

ECOGRAPHY, Issue 5 2005
Antonio J. Manzaneda
The predator-avoidance hypothesis states that once released from the parent plant, myrmecochorous seeds are rapidly taken by ants to their nests, where they are protected from predators. Previous studies conducted to test this hypothesis have frequently neglected two major aspects necessary for its verification: 1) the influence of processes acting after the seed release and 2) the spatial evenness of such processes. Thus, large-scale variations in the mechanisms acting beyond seed release, and possibly influencing seed escape from predators, remain poorly documented. Here, we present the results of a post-dispersal seed-removal experiment on the myrmecochorous herb Helleborus foetidus, aimed at verifing the predator-avoidance hypothesis by considering two key post-release aspects of seed fate: seed destination (dispersed or nondispersed) and seed burial (buried or not buried). Experiments were performed in four different regions in the Iberian Peninsula. After three days of exposure of seeds to the main predator (fieldmice Apodemus sylvaticus), ca 30% of the seeds were removed. Seed destination affected the proportion of seeds escaping predation, but the sign, magnitude and statistical significance of the effect varied among the geographical regions. In the southern region (Cazorla), seeds dispersed in ant nests or intermediate destinations suffered scarcely any predation, but seeds under reproductive-age plants experienced losses ca 50%. Conversely, in the northern region (Caurel), seeds in nests suffered significantly greater losses than seeds under plants or intermediate destinations, suggesting that nests were especially unsafe destinations. Seed burial had a strong impact on seed escape from predators, and its effect was highly consistent among geographical regions. In view of the consistency of its effect at different spatial scales, seed burial was a more general mechanism for predation avoidance than seed relocation to ant nests, which was habitat- and/or ant-species-dependent. Our results thus only partially support the predator-avoidance hypothesis for the evolution of myrmecochory. [source]


Changes in organic matter, nitrogen, phosphorus and cations in soil as a result of fire and water erosion in a Mediterranean landscape

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2000
E. Gimeno-García
Summary Fire affects large parts of the dry Mediterranean shrubland, resulting in erosion and losses of plant nutrients. We have attempted to measure these effects experimentally on a calcareous hillside representative of such shrubland. Experimental fires were made on plots (4 m × 20 m) in which the fuel was controlled to obtain two different fire intensities giving means of soil surface temperature of 439°C and 232°C with temperatures exceeding 100°C lasting for 36 min and 17 min. The immediate and subsequent changes induced by fire on the soil's organic matter content and other soil chemical properties were evaluated, together with the impact of water erosion. Seven erosive rain events, which occurred after the experimental fires (from August 1995 to December 1996), were selected, and on them runoff and sediment produced from each plot were measured. The sediments collected were weighed and analysed. Taking into account the variations induced by fire on the soil properties and their losses by water erosion, estimates of the net inputs and outputs of the soil system were made. Results show that the greatest losses of both soil and nutrients took place in the 4 months immediately after the fire. Plots affected by the most intense fire showed greater losses of soil (4077 kg ha,1) than those with moderate fire intensity (3280 kg ha,1). The unburned plots produced the least sediment (72.8 kg ha,1). Organic matter and nutrient losses by water erosion were related to the degree of fire intensity. However, the largest losses of N-NH4+ and N-NO3, by water erosion corresponded to the moderate fire (8.1 and 7.5 mg N m,2, respectively). [source]


Habitat loss, resource specialization, and extinction on coral reefs

GLOBAL CHANGE BIOLOGY, Issue 10 2004
Philip L. Munday
Abstract Coral reefs worldwide are being degraded because of global warming (coral bleaching) and coastal development (sedimentation and eutrophication). Predicting the risk of species extinctions from this type of habitat degradation is one of the most challenging and urgent tasks facing ecologists. Habitat specialists are thought to be more prone to extinction than generalists; however, specialists may be more susceptible to extinction because (1) they are specialists per se, (2) they are less abundant than generalists, or (3) both. Here, I show that declines in coral abundance lead to corresponding declines in the abundance of coral-dwelling fishes, but with proportionally greater losses to specialists than generalists. In addition, specialists have smaller initial population sizes than generalists. Consequently, specialists face a dual risk of extinction because their already small populations decline more rapidly than those of generalists. Corresponding with this increased extinction risk, I describe the local extinction of one specialist species and the near-global extinction of another species. I conclude that habitat specialists will be the first species lost from coral reefs because their small populations suffer the most from human-induced disturbances. [source]


Nursing shortages and international nurse migration

INTERNATIONAL NURSING REVIEW, Issue 4 2005
S. J. Ross mpa/id
Background:, The United Kingdom and the United States are among several developed countries currently experiencing nursing shortages. While the USA has not yet implemented policies to encourage nurse immigration, nursing shortages will likely result in the growth of foreign nurse immigration to the USA. Understanding the factors that drive the migration of nurses is critical as the USA exerts more pull on the foreign nurse workforce. Aim:, To predict the international migration of nurses to the UK using widely available data on country characteristics. Method:, The Nursing and Midwifery Council serves as the source of data on foreign nurse registrations in the UK between 1998 and 2002. We develop and test a regression model that predicts the number of foreign nurse registrants in the UK based on source country characteristics. We collect country-level data from sources such as the World Bank and the World Health Organization. Results:, The shortage of nurses in the UK has been accompanied by massive and disproportionate growth in the number of foreign nurses from poor countries. Low-income, English-speaking countries that engage in high levels of bilateral trade experience greater losses of nurses to the UK. Conclusion:, Poor countries seeking economic growth through international trade expose themselves to the emigration of skilled labour. This tendency is currently exacerbated by nursing shortages in developed countries. Countries at risk for nurse emigration should adjust health sector planning to account for expected losses in personnel. Moreover, policy makers in host countries should address the impact of recruitment on source country health service delivery. [source]


Reduction of Aflatoxins by Extrusion-Cooking of Rice Meal

JOURNAL OF FOOD SCIENCE, Issue 7 2006
Miren Castells
ABSTRACT:, The objective of this work was to determine the reduction of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2) as a function of initial moisture content of samples (24%, 27%, and 30%), barrel temperature (140, 170, and 200 °C), and residence time (30 to 70 s) when artificially contaminated rice meal was extrusion-cooked. Extruded and unextruded samples were analyzed by high-performance liquid chromatography (HPLC). Extrusion-cooking was observed to reduce aflatoxin (AF) content, which ranged from 51% to 95% depending on the type of AF and the studied variables. Only in the case of AFG2 was it found that the higher the temperature, the higher the moisture content, and the longer the residence time, the greater the reduction. Moisture content had a significant influence on reducing AFB2, AFG1, and AFG2 whereas it was not a significant factor affecting the levels of AFB1. Regardless of the type of AF, the lowest reductions were achieved at a temperature of 140 °C. Even though theoretically greater losses would be expected at highest temperature, AFB1 and AFB2 were more reduced by 170 °C than by 200 °C while AFG1 reductions were not statistically different when processing at 170 °C and 200 °C. The decrease of AF followed 1st-order kinetics; the fastest treatment in reducing AF was that at 200 °C when samples containing AFG2 were wetted to 24% and when samples containing AFB1, AFB2, and AFG1 were hydrated to 27%. By contrast, the slowest treatments were observed at a barrel temperature of 140 °C. [source]


Impaired bioavailability of vitamin A in adults and children with persistent diarrhoea in Zambia

ALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 7 2001
P. Kelly
Background: We have previously demonstrated a strong relationship between low serum retinol concentration and mortality in Zambian AIDS patients with diarrhoea, but were unable to detect any benefit from oral micronutrient supplementation. Aim: To test the hypothesis that this is related to impaired availability of vitamin A, we analysed serum retinol concentration changes over 6 h following oral mega-dose therapy (60, 120 or 180 mg retinol). Methods: Twenty-four men without diarrhoea, 15 adults with persistent diarrhoea and 11 children (six girls, five boys) with persistent diarrhoea were studied. Results: Men with persistent diarrhoea had lower baseline serum retinol concentrations (median 0.39 ,mol/L, interquartile range 0.21,0.56) than controls (median 1.16 ,mol/L, interquartile range 0.84,1.47; P=0.0003). After 60 mg retinol, the rise in serum retinol in HIV seropositive controls (median 0.63 ,mol/L, interquartile range 0.35,0.77) did not differ significantly from that observed in HIV seronegative controls (median 0.35 ,mol/L, interquartile range , 0.04,0.56; P=0.20). Increasing the dose to 120 mg or 180 mg retinol did not enhance the increase in serum retinol concentration. The increase in serum retinol was less in adults with persistent diarrhoea (median 0.25 ,mol/L, interquartile range 0.04,0.35) and in children (median 0.11 ,mol/L, interquartile range 0.04,0.46) than in men without diarrhoea (median 0.44 ,mol/L, interquartile range 0.26,0.74; P=0.03). Adults and children with diarrhoea had greater losses of retinol in urine over a 24-h period than controls, but less than 1% of the ingested dose was excreted. Conclusions: These results suggest that persistent diarrhoea in this population is associated with reduced bioavailability of retinol. Further work is required to determine the metabolic fate of therapeutic doses of retinol and to determine appropriate replacement strategies for HIV infected individuals. [source]


The product differentiation hypothesis for corporate trade credit

MANAGERIAL AND DECISION ECONOMICS, Issue 6-7 2003
George W. Blazenko
The product differentiation hypothesis for trade credit says that business managers use trade credit like advertising to differentiate their products. Prior studies of this hypothesis conclude that higher profit margins induce firms to increase trade credit and vice versa. We better represent the relation between the cost of bad debts and the price of the product offered on credit. When prices are higher, firms suffer greater losses from non-payment. Our model shows that, contrary to early versions of the product differentiation hypothesis, when managers adjust trade credit and profit margins for a perturbation in marginal cost, optimal profit margin and trade credit may move in opposite directions. A manager maintains revenue for price elastic demand by moderating the price increase, which decreases profit margin. At the same time, the manager also increases trade credit, which serves to maintain revenue by encouraging product demand. We report evidence of a negative relation between corporate receivables and profit margin. Copyright © 2003 John Wiley & Sons, Ltd. [source]