bluuebunny/crossref_metadata_2025 huggingface dataset:
Strabismus-mediated primary archenteron invagination is uncoupled from Wnt/β-catenin-dependent endoderm cell fate specification in Nematostella vectensis (Anthozoa, Cnidaria): Implications for the evolution of gastrulation
Authors: Kumburegama Shalika , Wijesena Naveen , Xu Ronghui , Wikramanayake Athula H
Published: January 2011

Background

Gastrulation is a uniquely metazoan character, and its genesis was arguably the key step that enabled the remarkable diversification within this clade. The process of gastrulation involves two tightly coupled events during embryogenesis of most metazoans. Morphogenesis produces a distinct internal epithelial layer in the embryo, and this epithelium becomes segregated as an endoderm/endomesodermal germ layer through the activation of a specific gene regulatory program. The developmental mechanisms that induced archenteron formation and led to the segregation of germ layers during metazoan evolution are unknown. But an increased understanding of development in early diverging taxa at the base of the metazoan tree may provide insights into the origins of these developmental mechanisms.

Results

In the anthozoan cnidarian Nematostella vectensis, initial archenteron formation begins with bottle cell-induced buckling of the blastula epithelium at the animal pole. Here, we show that bottle cell formation and initial gut invagination in Nematostella requires NvStrabismus (NvStbm), a maternally-expressed core component of the Wnt/Planar Cell Polarity (PCP) pathway. The NvStbm protein is localized to the animal pole of the zygote, remains asymmetrically expressed through the cleavage stages, and becomes restricted to the apical side of invaginating bottle cells at the blastopore. Antisense morpholino-mediated NvStbm-knockdown blocks bottle cell formation and initial archenteron invagination, but it has no effect on Wnt/ß-catenin signaling-mediated endoderm cell fate specification. Conversely, selectively blocking Wnt/ß-catenin signaling inhibits endoderm cell fate specification but does not affect bottle cell formation and initial archenteron invagination.

Conclusions

Our results demonstrate that Wnt/PCP-mediated initial archenteron invagination can be uncoupled from Wnt/ß-catenin-mediated endoderm cell fate specification in Nematostella, and provides evidence that these two processes could have evolved independently during metazoan evolution. We propose a two-step model for the evolution of an archenteron and the evolution of endodermal germ layer segregation. Asymmetric accumulation and activation of Wnt/PCP components at the animal pole of the last common ancestor to the eumetazoa may have induced the cell shape changes that led to the initial formation of an archenteron. Activation of Wnt/ß-catenin signaling at the animal pole may have led to the activation of a gene regulatory network that specified an endodermal cell fate in the archenteron.
Decreased Cerebrospinal Fluid/Plasma Ratio of the Novel Satiety Molecule, Nesfatin-1/NUCB-2, in Obese Humans: Evidence of Nesfatin-1/NUCB-2 Resistance and Implications for Obesity Treatment
Authors: Tan Bee K. , Hallschmid Manfred , Kern Werner , Lehnert Hendrik , Randeva Harpal S.
Published: January 2011

Context:

The novel adipokine, nesfatin-1/NUCB-2, reduces food intake, levels of which are elevated in overweight individuals.

Objectives:

The aim of the study was to investigate the mechanisms underlying brain nesfatin-1/NUCB-2 uptake and to determine whether reduced uptake may contribute to nesfatin-1/NUCB-2 resistance.

Design:

Cerebrospinal fluid (CSF) and corresponding plasma nesfatin-1/NUCB-2 were measured by ELISA [18 men and 20 women; age, 19–80 yr; body mass index (BMI), 16.2–38.1 kg/m2] and correlated to body adiposity and metabolic parameters.

Results:

CSF/plasma nesfatin-1/NUCB-2 ratio was significantly negatively associated with BMI, body weight, fat mass, and CSF glucose. BMI was predictive of CSF/plasma nesfatin-1/NUCB-2 ratio (β = −0.786; P = 0.045). CSF nesfatin-1/NUCB-2 was significantly positively associated with plasma nesfatin-1/NUCB-2 (R = 0.706; P < 0.01). There was a significant linear relation between CSF and plasma nesfatin-1/NUCB-2 in lean (BMI <25 kg/m2; R = 0.744; P = 0.002) and obese (BMI ≥30 kg/m2; R = 0.693; P = 0.026) subjects. Subjects in the highest plasma nesfatin-1/NUCB-2 quintile had lower CSF/plasma nesfatin-1/NUCB-2 ratio [26.5% (26.0–29.5%)] compared to the lowest plasma nesfatin-1/NUCB-2 quintile [38.5% (34.0–42.0%)] (P < 0.01), corresponding BMI [32.4 (31.0–35.0) vs. 23.3 (19.7–23.5) kg/m2; P < 0.01], and fat mass [32.8 (29.5–40.6) vs. 30.7 (8.2–20.1) kg/m2; P < 0.01].

Conclusions:

Our observations have important implications with respect to the potential weight-reducing actions of nesfatin-1/NUCB-2 treatment. Future research should seek to clarify whether nesfatin-1/NUCB-2 would be beneficial in the management of obesity.
Prolonged Exercise-Induced Stimulation of Skeletal Muscle Glucose Uptake Is due to Sustained Increases in Tissue Perfusion and Fractional Glucose Extraction
Authors: Hamrin K. , Qvisth V. , Hagström-Toft E. , Enoksson S. , Henriksson J. , Bolinder J.
Published: January 2011

Context:

The mechanisms behind the positive effects of physical activity on glucose metabolism in skeletal muscle and the time course of the effects need to be more elucidated.

Objective:

The aim was to examine the prolonged effects of an acute bout of one-legged exercise on local skeletal muscle glucose utilization and tissue perfusion.

Design and Setting:

Interstitial glucose concentration, local tissue perfusion, glucose uptake, and effects of insulin infusion were studied 12 h after an acute bout of exercise and without prior exercise.

Participants:

Ten healthy subjects, five women and five men, participated in the study.

Intervention:

Microdialysis measurements, 133Xe clearance, and a 2-h hyperinsulinemic euglycemic clamp were performed on two occasions.

Main Outcome Measures:

We measured interstitial glucose concentration and tissue perfusion in the quadriceps femoris muscle of both legs.

Results:

Tissue perfusion (3.3 ± 0.6 ml × 100 g−1 × min−1vs. 1.4 ± 0.2 ml × 100 g−1 × min−1; P = 0.007) and basal glucose uptake (2.3 ± 0.5 μmol × 100 g−1 × min−1vs. 0.9 ± 0.2 μmol × 100 g−1 × min−1; P = 0.006) were increased in the leg that had exercised compared to the resting leg; the findings in the resting leg were comparable to those in the control experiment without prior exercise. The relative effect of insulin on fractional skeletal muscle glucose uptake was the same in all experimental settings, and insulin did not affect tissue perfusion.

Conclusions:

The prolonged stimulatory effect of physical exercise on skeletal muscle glucose uptake was mediated via vascular effects combined with an increase in basal glucose transport independent of enhancement of insulin responses.
A Dual Sugar Challenge Test for Lipogenic Sensitivity to Dietary Fructose
Authors: Hudgins Lisa C. , Parker Thomas S. , Levine Daniel M. , Hellerstein Marc K.
Published: January 2011

Context:

Increased hepatic de novo lipogenesis (DNL) in response to dietary sugar is implicated in dyslipidemia, fatty liver, and insulin resistance.

Objective:

The aim of the study was to develop a simple outpatient tolerance test for lipogenic sensitivity to dietary sugar.

Design and Setting:

In inpatients given repeated doses of fructose, protocol 1 compared the acute increase in DNL determined from the percentage of palmitate (“new palmitate”) and the percentage of isotopically labeled palmitate (“%DNL”) in very low-density lipoprotein triglyceride (TG). Protocol 2 compared the increase in new palmitate in outpatients given three different sugar beverages in a randomized crossover design.

Participants:

There were 15 lean and overweight volunteers in protocol 1 and 15 overweight volunteers in protocol 2.

Interventions:

In protocol 1, subjects received 1.4 g/kg fructose in divided oral doses over 6 h; in protocol 2, subjects received 0.5 g/kg fructose, 0.5 g/kg fructose plus 0.5g/kg glucose, or 1 g/kg fructose plus 1g/kg glucose each as a single oral bolus.

Main Outcome Measures:

We measured the increase in DNL by two methods.

Results:

After repeated doses of fructose, new palmitate was significantly correlated with the increase in %DNL (Δ, r = 0.814; P < 0.001) and with fasting insulin levels (area under the curve, r = 0.754; P = 0.001). After a single sugar dose, new palmitate showed a dose effect and was greater after fructose plus glucose. Very low-density lipoprotein TG and total TG significantly increased in both protocols.

Conclusions:

A single oral bolus of fructose and glucose rapidly increases serum TG and TG palmitate in overweight subjects. A dual sugar challenge test could prove useful to identify individuals at risk for carbohydrate-induced dyslipidemia and other adverse effects of increased DNL.
Three Weeks on a High-Fat Diet Increases Intrahepatic Lipid Accumulation and Decreases Metabolic Flexibility in Healthy Overweight Men
Authors: van Herpen Noud A. , Schrauwen-Hinderling Vera B. , Schaart Gert , Mensink Ronald P. , Schrauwen Patrick
Published: January 2011

Context:

In rodents, high-fat diets increase intrahepatic lipid (IHL), but human studies are scarce.

Objective:

Our objective was to examine whether high-fat diets influence IHL, intramyocellular lipids (IMCL), and insulin resistance.

Design:

Twenty overweight men were randomly allocated to low- or high-fat groups (age, 54.0 ± 2.3 and 56.4 ± 2.5 yr; body mass index, 29.3 ± 0.6 and 28.3 ± 0.5 kg/m2, respectively). Both groups started with a 3-wk low-fat diet [15% energy (En%) as protein, 65 En% as carbohydrates, 20 En% as fat], after which half of the subjects switched to a 3-wk isocaloric high-fat diet (15 En% protein, 30 En% carbohydrates, 55 En% fat). After 3 and 6 wk, IHL and IMCL content were assessed by 1H magnetic resonance spectroscopy and a muscle biopsy, and insulin sensitivity was studied using a hyperinsulinemic-euglycemic clamp. An additional liver scan was performed after 1 wk in the high-fat group.

Results:

IHL decreased by 13% in the low-fat group and increased by 17% in high-fat group (P = 0.047). IMCL content was unaffected (P = 0.304). Insulin sensitivity was unaffected. At wk 3, IHL correlated negatively with insulin sensitivity (r = −0.584; P = 0.009, all subjects combined). Metabolic flexibility, defined as change in respiratory quotient upon insulin stimulation, was decreased after 3 wk of the high-fat diet (change in respiratory quotient was +0.02 ± 0.02 vs. −0.05 ± 0.1 in low-fat vs. high-fat group, P = 0.009). Basal plasma glucose increased after the high-fat diet (P = 0.038). Plasma parameters insulin, free fatty acids, high-sensitivity C-reactive protein, and liver enzymes and body weight were unaffected by diet.

Conclusion:

A 3-wk high-fat diet leads to IHL accumulation and a decreased metabolic flexibility, but insulin sensitivity is unaffected.
Running on Empty? Financial Leverage and Product Quality in the Supermarket Industry
Authors: Matsa David A
Published: January 2011

This paper examines whether debt financing can undermine a supermarket firm's incentive to provide product quality. In the supermarket industry, product availability is an important measure of a retailer's quality. Using US consumer price index microdata to track inventory shortfalls, I find that taking on high financial leverage increases shortfalls. Highly leveraged firms appear to be degrading their products' quality in order to preserve current cash flow for debt service. Although reducing quality can erode both current sales and customer loyalty, firms appear to be willing to risk these outcomes in order to achieve benefits associated with debt finance. (JEL D92, G31, G32, L15, L81)
Noncompete Covenants: Incentives to Innovate or Impediments to Growth
Authors: Samila Sampsa , Sorenson Olav
Published: January 2011

We find that the enforcement of noncompete clauses significantly impedes entrepreneurship and employment growth. Based on a panel of metropolitan areas in the United States from 1993 to 2002, our results indicate that, relative to states that enforce noncompete covenants, an increase in the local supply of venture capital in states that restrict the scope of these agreements has significantly stronger positive effects on (i) the number of patents, (ii) the number of firm starts, and (iii) employment. We address potential endogeneity in the supply of venture capital by using endowment returns as an instrumental variable. Our results point to a strong interaction between financial intermediation and the legal regime in promoting entrepreneurship and economic growth.

This paper was accepted by Gérard P. Cachon, entrepreneurship and innovation.
Protective effect of estrogens on the brain of rats with essential and endocrine hypertension
Authors: De Nicola Alejandro F. , Pietranera Luciana , Bellini Maria José , Goya Rodolfo , Brocca Maria Elvira , Garcia-Segura Luis Miguel
Published: January 2011

Estrogen neuroprotection has been shown in pathological conditions damaging the hippocampus, such as trauma, aging, neurodegeneration, excitotoxicity, oxidative stress, hypoglycemia, amyloid-β peptide exposure and ischemia. Hypertensive encephalopathy also targets the hippocampus; therefore, hypertension seems an appropriate circumstance to evaluate steroid neuroprotection. Two experimental models of hypertension, spontaneously hypertensive rats (SHR) and deoxycorticosterone (DOCA)-salt hypertensive rats, develop hippocampal abnormalities, which include decreased neurogenesis in the dentate gyrus, astrogliosis, low expression of brain-derived neurotrophic factor (BDNF) and decreased number of neurons in the hilar region, with respect of their normotensive strains Wistar Kyoto (WKY) and Sprague-Dawley rats. After estradiol was given for 2 weeks to SHR and DOCA-treated rats, both hypertensive models normalized their faulty hippocampal parameters. Thus, estradiol treatment positively modulated neurogenesis in the dentate gyrus of the hippocampus, according to bromodeoxyuridine incorporation and doublecortin immunocytochemistry, decreased reactive astrogliosis, increased BDNF mRNA and protein expression in the dentate gyrus and increased neuronal number in the hilar region of the dentate gyrus. A role of local estrogen biosynthesis is suggested in SHR, because basal aromatase mRNA in the hippocampus and immunoreactive aromatase protein in cell processes of the dentate gyrus were highly expressed in these rats. Estradiol further stimulated aromatase-related parameters in SHR but not in WKY. These observations strongly support that a combination of exogenous estrogens to those locally synthesized might better alleviate hypertensive encephalopathy. These studies broaden estrogen neuroprotective functions to the hippocampus of hypertensive rat models.
New insights into the protective effects of DHEA1)
Authors: Niro Sandra , Hennebert Olivier , Morfin Robert
Published: January 2011

Numerous studies investigated the effects of pharmacological doses of DHEA in animals. Among protective effects, antiglucocorticoid potencies, triggering and modulation of immunity and anticancerous effects were reported. Because DHEA levels decrease in aging humans, this steroid has been assayed as replacement therapy in elderly volunteers without striking evidence for beneficial effects. Examination of the investigations carried out in animals lead to suspect that, rather than DHEA, its metabolites produced in tissues could be responsible for some of the observed effects. Known as the “mother steroid”, DHEA is a precursor for androgenic and estrogenic steroid hormones. In addition, DHEA is hydroxylated at the 7α position by the cytochrome P450 7B1 (CYP7B1), and the 7α-hydroxy-DHEA produced is a substrate for the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which converts it into 7β-hydroxy-DHEA. Both 7-hydroxylated metabolites were shown to favor the onset of immunity in mice and the activation of memory T cells in humans. Other DHEA and testosterone-derived metabolites, namely epiandrosterone and 5α-androstane-3β,17β-diol, are also substrates for the CYP7B1 and their 7α-hydroxylated products were also converted into the 7β epimer by the 11β-HSD1. When assayed at doses 104 lower than DHEA, 7β-hydroxy-epiandrosterone was shown to shift the prostaglandin metabolism patterns from prostaglandin E2 (PGE2) to PGD2 production, thus triggering the resolution of inflammation. In addition, 7β-hydroxy-epiandrosterone (1 nM) exerted the same effects as tamoxifen (1 μM) on the proliferation of MCF-7 and MDA-231 human breast cancer cells. These findings suggest that the observed effects of 7β-hydroxy-epiandrosterone could be mediated by estrogen receptors. This overview of recent research implies that DHEA does not act directly and that its effects are due to its metabolites when produced in tissues. Treatments with DHEA should take into account the target tissue abilities to produce the desired metabolites through the two key enzymes, CYP7B1 and 11β-HSD1.
Role of androgens in modulating male and female sexual function
Authors: Traish Abdulmaged M.
Published: January 2011

Advancement in basic and clinical research has provided considerable evidence suggesting a key role of androgens in the physiology and pathophysiology of sexual function. Evidence from clinical studies in men and women with androgen deficiency support a role of androgens in maintaining sexual function in men and women and are integral in maintaining sexual health. Preclinical studies utilizing male animal models demonstrated a role of androgens in maintenance of: (i) penile tissue structural integrity, (ii) penile trabecular smooth muscle growth and function, (iii) integrity of penile nerve fiber network, (iv) signaling pathways in the corpora cavernosa, (v) myogenic and adipogenic differentiation in the corpora cavernosa, (vi) physiological penile response to stimuli, and (vii) facilitating corporeal hemodynamics. These findings strongly suggest a role for androgen in the physiology of penile erection. In addition, clinical studies in hypogonadal men with erectile dysfunction treated with testosterone provided invaluable information on restoring erectile function and improving ejaculatory function. Similarly, clinical studies in surgically or naturally postmenopausal women with androgen deficiency suggested that androgens are important for maintaining sexual desire and testosterone treatment was shown to improve sexual desire, arousal and orgasm. Furthermore, studies in female animal models demonstrated that androgens maintain the integrity of vaginal nerve fiber network, muscularis volume, and enhance genital blood flow and mucification. Based on the biochemical, physiological and clinical findings from human and animal studies, we suggest that androgens are integral for maintaining sexual function and play a critical role in maintaining sexual health in men and women.
Progesterone as a regulator of phosphorylation in the central nervous system
Authors: Amorim Miguel A.R. , Guerra-Araiza Christian , Garcia-Segura Luis M.
Published: January 2011

Progesterone exerts a variety of actions in the central nervous system under physiological and pathological conditions. As in other tissues, progesterone acts in the brain through classical progesterone receptors and through alternative mechanisms. Here, we review the role of progesterone as a regulator of kinases and phosphatases, such as extracellular-signal regulated kinases, phosphoinositide 3-kinase, Akt, glycogen synthase kinase 3, protein phosphatase 2A and phosphatase and tensin homolog deleted on chromosome 10. In addition, we analyzed the effects of progesterone on the phosphorylation of Tau, a protein that is involved in microtubule stabilization in neurons.
Androgen modulation of pro-inflammatory and anti-inflammatory cytokines during preadipocyte differentiation
Authors: Pierotti Silvia , Lolli Francesca , Lauretta Rosa , Graziadio Chiara , Di Dato Carla , Sbardella Emilia , Tarsitano Maria Grazia , Isidori Aldo , Bonifacio Vincenzo , Lenzi Andrea , Isidori Andrea M.
Published: January 2011

Background: Macrophages and adipocytes contribute to release of cytokines resulting in the chronic inflammatory profile of the metabolic syndrome. The local increase of proinflammatory cytokines impairs adipogenesis, resulting in formation of dysfunctional adipocytes that are unable to store and handle lipids. The altered lipid fluxes in/from adipocytes affect whole-body metabolism. We investigated the role of androgens on adipocyte-derived proinflammatory and anti-inflammatory cytokines during preadipocyte differentiation.

Materials and methods: Various differentiation methods were used to obtain full conversion of 3T3-L1 into mature adipocytes. The degree of adipocyte conversion in the presence/absence of dihydrotestosterone (DHT) was analyzed by measuring intracellular triglycerides (Oil Red O staining). The effects of DHT administration on interleukin 1β (IL-1β), IL-2, IL-6, IL-10, IL-12, interferon γ (IFNγ) and tumor necrosis factor α (TNFα) secretion was measured at days 0, 4, 6 and 8 of differentiation using the SearchLight multiplex protein array.

Results: DHT regulates a number of cytokines in committed and mature 3T3-L1 adipocytes. IL-1β and TNFα were readily suppressed at the very early stages of differentiation. IFNγ release was inhibited at day 4, but the effect was no longer detectable on day 8. IL-6 and IL-12 were significantly reduced at day 8 of differentiation. Conversely, the differentiation-dependent increase of IL-2 and IL-10 was further stimulated by DHT since day 0.

Conclusions: We provide evidence that androgens promote an anti-inflammatory profile that parallels the acquisition of a functional adipocyte phenotype. The crosstalk between androgens, adipocyte-derived mediators of inflammation and intracellular lipid fluxes could have profound implications on metabolism of men with obesity and metabolic syndrome.
Intravaginal DHEA, by a strictly local action, exerts beneficial effects on both vaginal atrophy symptoms and sexual dysfunction
Authors: Labrie Fernand
Published: January 2011

Background: Following complete cessation of estrogen secretion by the ovaries at menopause, all estrogens and practically all androgens are made from dehydroepiandro-sterone (DHEA) of adrenal/ovarian origin. Although being an inactive molecule itself, DHEA is transformed at various levels and ratios into estrogens and/or androgens only in the tissues that possess the required cell-specific steroidogenic enzymes with minimal or no release of the active hormones in the blood according to the mechanisms of intracrinology. Vaginal atrophy affects 50% of postmenopausal women from 50 to 60 years of age and 72% of women 70 years and older.

Methods and results: At the standard 12-week time interval, 0.5% DHEA caused a 45.9±5.31 (p<0.0001 vs. placebo) decrease in the percentage of parabasal cells, a 6.8%±1.29% (p<0.0001 vs. placebo) increase in superficial cells, a 1.3±0.13 unit (p<0.0001 vs. placebo) decrease in vaginal pH and a 1.5±0.14 score unit (p<0.0001 vs. placebo) decrease in the severity of the most bothersome symptom. Similar changes were observed on vaginal secretions, color, epithelial surface thickness and epithelial integrity. In addition to the effects of intravaginal DHEA on the symptoms and signs of vaginal atrophy, a time- and dose-dependent improvement in the four domains of sexual function was observed, namely desire, arousal, orgasm and pain at sexual intercourse.

Conclusions: The present data indicate that combined androgenic/estrogenic stimulation in the three layers of the vagina exerts important beneficial effects on sexual function in women without systemic action on the brain and other extravaginal tissues.
Peroxisome proliferator-activated receptor β/δ: a master regulator of metabolic pathways in skeletal muscle
Authors: Lahiri Shawon , Wahli Walter
Published: January 2011

Skeletal muscle is considered to be a major site of energy expenditure and thus is important in regulating events affecting metabolic disorders. Over the years, both in vitro and in vivo approaches have established the role of peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) in fatty acid metabolism and energy expenditure in skeletal muscles. Pharmacological activation of PPARβ/δ by specific ligands regulates the expression of genes involved in lipid use, triglyceride hydrolysis, fatty acid oxidation, energy expenditure, and lipid efflux in muscles, in turn resulting in decreased body fat mass and enhanced insulin sensitivity. Both the lipid-lowering and the anti-diabetic effects exerted by the induction of PPARβ/δ result in the amelioration of symptoms of metabolic disorders. This review summarizes the action of PPARβ/δ activation in energy metabolism in skeletal muscles and also highlights the unexplored pathways in which it might have potential effects in the context of muscular disorders. Numerous preclinical studies have identified PPARβ/δ as a probable potential target for therapeutic interventions. Although PPARβ/δ agonists have not yet reached the market, several are presently being investigated in clinical trials.
Life-History Traits of the Predatory LacewingDichochrysa prasina(Neuroptera: Chrysopidae): Temperature-Dependent Effects When Larvae Feed on Nymphs ofMyzus persicae(Hemiptera: Aphididae)
Authors: Pappas M L , Koveos D S
Published: January 2011

The predatory lacewing Dichochrysa prasina Burmeister (Neuroptera: Chrysopidae) is an abundant cosmopolitan species. In Greece, it is widespread in orchards and vegetable and field crops, and it has been considered an important biocontrol agent of aphids. In this work, the preimaginal development and adult longevity and reproduction of D. prasina were studied at six constant temperatures (15, 20, 25, 27, 30, and 33°C) and a photoperiod of 16:8 (L:D) h under laboratory conditions. Nymphs of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), were offered as prey throughout larval development. At the highest tested temperature of 33°C, no larvae completed development. At the rest temperatures, developmental time for preimaginal stages decreased from 136.0 to 29.2 d at 15 and 30°C, respectively. Percentages of adult emergence ranged from 48 to 76% at the temperatures tested. The estimated thermal requirements for total preimaginal development were 583.4 degree-days, whereas the upper and lower threshold temperatures were 32.9 and 9.9°C, respectively. Both female longevity and egg production were significantly affected by temperature. The intrinsic rate of increase (rm) ranged from 0.01631 to 0.08739, with the highest value recorded at 27°C (0.09831). The rm values determined at different temperatures fitted to Lactin's nonlinear model. The lower and upper threshold and optimal temperatures for population increase were 13.1, 33.1, and 27.2°C, respectively. The results of the current study could be useful for explaining phenology and population dynamics of this indigenous predator in the field.
Egg Morphology ofAnastrephaspp. (Diptera: Tephritidae) in thefraterculusGroup using Scanning Electron Microscopy
Authors: Dutra Vivian S , Ronchi-Teles Beatriz , Steck Gary J , Silva Janisete G
Published: January 2011

We describe detailed scanning electron microscopic (SEM) observations of eggs of six Anastrepha species in the fraterculus group: Anastrepha antunesi Lima, Anastrepha bahiensis Lima, Anastrepha coronilli Carrejo & González, Anastrepha distincta Greene, Anastrepha turpiniae Stone, and Anastrepha zenildae Zucchi, for the first time. Eggs were dissected from females captured in McPhail traps in Cariri in the state of Tocantins; Itacoatiara, Manaus, and Presidente Figueiredo in the state of Amazonas; and Porto Velho in the state of Rondônia, in the Brazilian Amazon. Eggs were examined using both scanning electron and optical microscopes. At least 10 eggs were examined for each species by using SEM, and 20–35 eggs per female of at least three females of each species were prepared for light microscopy. The eggs of all six species are similar in gross morphology. They are tapered at both ends, have a papilla at the anterior pole, and the micropyle is located on the dorsal side near the anterior pole. Diagnostic characters to differentiate among these six species include the chorion ornamentation, location of aeropyles, and a pronounced rim of the chorion with a woolly appearance surrounding the micropyle. None of the eggs of the studied species had a conspicuous respiratory appendage.
Decision support system for irrigation maintenance in Indonesia: a multi-objective optimization study
Authors: Hadihardaja Iwan K. , Grigg Neil S.
Published: January 2011

Maintenance of irrigation infrastructure is essential to sustain food production and farmers' earnings. Given the shortage of funds for maintenance in developing countries, it is critical to understand the degradation of the function of irrigation systems so that optimal budget allocations can be made. A case study of Indonesia proposes an Infrastructure Density Index that can be used to justify budgets for regions with distinct characteristics. Current policy and practice in Indonesia is to allocate the budget uniformly, based on unit cost per hectare. Thus, the existing system provides unvarying budgets without considering the irrigation assets in each network system of a region. Regional differences should be taken into consideration during budget allocations since each region has different infrastructure characteristics related to the density of hydraulic structures, length of irrigation canals, and area of the irrigation system. A budgeting model has been developed by using non-linear programming and an analytic hierarchy process to promote more reasonable budgeting allocation policy. The case study focuses on seven irrigation regions in West Java Province, Indonesia. Fair budgeting strategy is illustrated by the relationship between structure density and the Budgeting Index.
Understanding irrigation water use efficiency at different scales for better policy reform: a case study of the Murray-Darling Basin, Australia
Authors: Qureshi M. Ejaz , Grafton R. Quentin , Kirby Mac , Hanjra Munir A.
Published: January 2011

This paper examines water use efficiency and economic efficiency with a particular focus on the Murray-Darling Basin of Australia and the stated policy goal of increasing environmental flows of water in the Basin. The different measures of efficiency are explained, and their implications for water reform and the efficacy of market based approaches to addressing the water scarcity issues and environmental flow needs are explored. Public policies to subsidize investments for improvements in irrigation efficiency are shown not to be currently cost effective compared to alternatives, such as buying water through water markets. The implications of these findings, and the factors that determine the demand for irrigation water by competing uses, can guide policy makers undertaking water reforms in the agricultural sector to mitigate the environmental consequences of overuse of water resources.
Institutional capacity and policy options for integrated urban water management: a Singapore case study
Authors: Chen Deh Chien , Maksimovic Cedo , Voulvoulis Nikolaos
Published: January 2011

Singapore is an exemplary model of integrated water management, according to the World Health Organization, and its experiences can be shared with others. Water security is not just the government's responsibility but has become everyone's business. Singapore has been selected as a case study for integrated urban water management (IUWM), and the methodologies used in Singapore, a developed city state, may be applicable elsewhere. An integrated regulatory framework, sound policies to control and implement programmes, public-private partnership in water services delivery, and stakeholder participation at all levels are necessary to make integrated water resource management successful. This paper demonstrates how Singapore has successfully turned its vulnerability with regard to water into a strength. Singapore can achieve greater sustainability if it promotes rooftop rainwater harvesting as a decentralized, dual-mode water supply system for non-potable use.
Balloon kyphoplasty in the treatment of metastatic tumors of the upper thoracic spine
Authors: Eleraky Mohammed , Papanastassiou Ioannis , Setzer Matthias , Baaj Ali A. , Tran Nam D. , Vrionis Frank D.
Published: January 2011

Object

Balloon kyphoplasty has recently been shown to be effective in providing rapid pain relief and enhancing health-related quality of life in patients with metastatic spinal tumors. When performed to treat lesions of the upper thoracic spine, kyphoplasty poses certain technical challenges because of the smaller size of the pedicle and vertebral bodies. Fluoroscopic visualization is also difficult due to interference of the shoulder. The authors' objective in the present study was to evaluate their approach and the results of balloon kyphoplasty in the upper thoracic spine in patients with metastatic spinal disease.

Methods

Fourteen patients underwent kyphoplasty via an extrapedicular approach to treat metastatic tumors in the upper (T1–5) thoracic spine. Electrodiagnostic monitoring (somatosensory and motor evoked potentials) was used in 5 cases. Three levels were treated in 7 cases, 2 levels in 2 cases, and 1 level in 5 cases. In 3 cases access was bilateral, whereas in 11 cases access was unilateral. The procedure took an average of 25 minutes per treated level, and the mean amount of cement applied was 3 ml per level. Four patients were discharged from the hospital on the day of the procedure, and 10 patients went home after 24 hours.

Results

All patients exhibited marked improvement in mean visual analog scale scores (preoperative score 79 vs postoperative score 30, respectively) and Oswestry Disability Index scores (83 vs 33, respectively). The mean kyphotic angle was 25.03° preoperatively, whereas the mean postoperative angle was 22.65° (p > 0.3). At latest follow-up, the mean kyphotic angle did not differ significantly from the postoperative kyphotic angle (26.3°, p > 0.1).

No neurological deficits or lung-related complications (pneumothorax or hemothorax) were encountered in any of the patients. Polymethylmethacrylate cement extravasations were observed in 3 (10%) of 30 treated vertebral bodies without any sequelae. By a mean follow-up of 16 months, no patients had experienced an adjacent-level fracture.

Conclusions

Balloon kyphoplasty of the upper thoracic spine via an extrapedicular approach is an efficient and safe minimally invasive procedure that may provide immediate and long-term pain relief and improvement in functional ability. It is technically challenging and has the potential for serious complications. With a fundamental knowledge of anatomy, as well as an ability to interpret fluoroscopy images, one can feasibly and safely perform balloon kyphoplasty in the upper thoracic spine.
Posterior epidural migration of herniated lumbar disc fragment
Authors: Sengoz Ahmet , Kotil Kadir , Tasdemiroglu Erol
Published: January 2011

Object

Posterior epidural migration of a free disc fragment in the lumbar region is a very rare condition that has only been reported in isolated cases to date. Patients with this condition present with radiculopathy or major neurological deficits. Difficulties in diagnosis and the choice and timing of surgical treatment are important in these cases. In this clinical case series, features of cases with posterior epidural migration of free lumbar disc fragments accompanied by cauda equina syndrome are discussed.

Methods

Eight cases (0.27%) of posterior epidural migration of disc fragments were detected among 2880 patients surgically treated for lumbar disc herniation between 1995 and 2008. Seven of these patients had cauda equina syndrome. The mean duration of symptoms in the 8 cases was 4.2 days (range 1–10 days). The group included 6 men and 2 women, with a mean age of 48 years (range 34–72 years). The sequestered disc fragments were at the L3–4 level in 6 patients (75%) and the L4–5 level in 2 (25%). Magnetic resonance imaging showed tumor-like ring contrast enhancement around sequestered fragments in 5 patients. The patients' motor, sensory, sexual, and urological functions were evaluated postoperatively, and modified Odom criteria and a visual analog scale were used in the assessment of postoperative outcomes.

Results

A microsurgical approach was used in all cases. Sequestrectomy with minimal hemilaminotomy and removal of the free segments were performed. The patients were followed up for a mean period of 28.5 months. Three patients (37.5%) had excellent results, 3 (37.5%) had good results, 1 patient (12.5%) had fair results, and only 1 patient had poor results according to the Odom criteria. The main factors affecting the long-term outcomes were the presence of cauda equina syndrome and the time period between onset of symptoms and surgery.

Conclusions

Patients with posterior migration of a disc fragment present with severe neurological deficits such as cauda equina syndrome. Because the radiological images of disc fragments may mimic those of other more common posterior epidural space–occupying lesions, definite diagnosis of posteriorly located disc fragments is difficult. All of these lesions can be completely removed with hemilaminotomy and sequestrectomy, and early surgical treatment is important as a first choice to prevent severe neurological deficits.
Transfer of the teres minor motor branch for triceps reinnervation in tetraplegia
Authors: Bertelli Jayme Augusto , Ghizoni Marcos Flávio , Tacca Cristiano Paulo
Published: January 2011

In a case involving tetraplegia and paralysis of elbow extension, the authors transferred teres minor branches to the nerve of the triceps long head. Surgery was performed bilaterally 9 months after the patient sustained a spinal cord injury. Fourteen months postoperatively, elbow extension was complete (British Medical Research Council Score M4). Harvesting of the teres minor motor branch produced no deficits in shoulder function. In patients with tetraplegia, nerve transfer seems to be a promising new alternative for elbow extension reconstruction.
In vitro comparison of the pullout strength of 3 anterior double-screw fixation techniques with different screw angulations
Authors: Fuerderer Sebastian , Vonhoegen Jan , Coenen Oliver , Michael Joern , Koebke Juergen , Eysel Peer
Published: January 2011

Object

The pullout resistance of double-screw fixation systems in anterior spine surgery has been shown to be dependent on screw length as well as on screw angulation. The objective of the study was to evaluate the pullout strength of anterior double-screw systems with different angulations.

Methods

The authors conducted a comparative pullout test of converging, parallel, and diverging angulations of double-screw systems in human cadavers. Twenty-four human vertebral bodies from T-11 to L-1 were harvested from 8 donors, dissected from surrounding tissue, and matched to 3 different fixation groups. Three systems were tested: VentroFix, with near parallel screw direction; the Hopf Anterior Fixation System (HAFS), with converging screw angulation; and the ART anterior system, with diverging screw angulation.

Results

The mean (± SD) pullout strength of the VentroFix system was 699 ± 214 N, whereas the HAFS resisted to 591 ± 372 N. The ART anterior system with diverging screws demonstrated a pullout resistance of 810 ± 273 N. There was no significant difference amongst the pullout forces of the 3 groups (p > 0.05). In the HAFS and the ART anterior group, a weak correlation of pullout strength and bone mineral density measured by quantitative CT was found (r = 0.59 and r = 0.62, respectively), whereas the pullout force of the VentroFix system was not correlated with bone mineral density (r = 0.33).

Conclusions

The in vitro pullout resistance of anterior double-screw systems does not appear to depend on screw angulation.
Sediment Source for Melt-Water Deposits
Authors: Pessl Fred , Frederick Jan E.
Published: January 2011

A question is posed regarding the source of melt-water sediment. Does stagnant ice, functionally separated from active ice and gradually melting in place, contain enough rock debris to account for the volume of melt-water deposits known to exist in deglaciated areas, or does the volume of these deposits require a sediment source in close association with active ice from which the supply of rock debris is continually replenished?

Differing opinions on this question are implied in two contrasting models for deglaciation in the north-eastern United States. One, involving regional stagnation, assumes a sediment source in stagnant glacier ice; the other, involving stagnation-zone retreat, considers active ice the principal sediment source. This paper presents reported values of debris content in glacier ice and uses these values to calculate theoretical sediment volumes for a small drainage basin (1 300 km2) in northeastern U.S.A.

A typical value for the amount of rock debris in temperate glacier ice is 25% (volume) debris content in a 400 mm-thick basal debrisrich zone. This value gives a calculated sediment volume of 0.13 km3, about 6% of the estimated actual volume of melt-Hater sediment in the test basin. Comparison of calculated theoretical sediment volume with the estimated actual sediment volume in the basin indicates that stagnant ice is an inadequate sediment source, and that active ice, rather than stagnant ice, is probably the principal sediment source for melt-water deposits.
Glaciomarine Sediments and Suspended Particulate Matter, Weddell sea, Antarctica (Abstract only)
Authors: Elverhøi Anders , Roaldset Elen
Published: January 2011

Samples of glaciomarine sediments and suspended particulate matter filtered from sea-water were collected in the Weddell Sea during the Norwegian Antarctic Research Expedition (NARE) in 1978–79. Analyses have provided information on the textural and mineralogical composition of shelf sediments, on the nature of biogenic and inorganic suspended particulate matter, and on the total sediment transport to the shelf areas and further into the deeper waters (Orheim and Elverhøi 1981).

The shelf waters contain 0.1 to 1.2 g m–3 of suspended particulate matter, which is close to the range of 0.5 to 1.5 g m–3 reported for suspension concentrations in the oceans, but considerably lower than that found for some other glaciomarine environments such as the Bering Sea {up to 13-15 g m–3 (Lisitzin 1972)) and off Kongsbreen, Spitsbergen {up to 500 g m–3 (Elverhøi and others 1980)).

Suspended particles from the Weddell Sea have maximum sizes of 50 to 70 µm and mean diameters in the range of 10 to 20 µm. In contrast, the bottom sediments on the outer shelf are deficient in the corresponding fractions. This reflects that when floating Antarctic ice supplies material to the Weddell Sea, the coarser fragments (>20-70 µm) are deposited, while the medium silt and finer fractions go into suspension. Considering the suspended-load data and the bottom-current measurements on the shelf break, it is evident that in January 1979 an average of 8.6 × 104tonnes d–1 (or 32 × 106 tonnes a–l) of particulate matter was transported by the current from the central Weddell Sea to the South Atlantic deep water. Morphological (scanning electron microscopy) and chemical analyses show the suspended material to be dominated by silica organisms (diatoms), and also to contain clastic grains of phyllosilicates, feldspar, quartz, zircon, in a few cases Al- and Fe-hydroxides/oxides also; authigenic “Fe-sepiolite” and secondary gypsum.

Mineralogical analyses (X-ray diffraction) of the bottom sediments show the fine sand silt fractions to contain mainly clastic materials like illite, smectite-vermiculite, and quartz. Biogenic silica (cristobalite) and carbonate (Mg-calcite) as well as authigenic Fe-silicates (“Fe-sepiolite”) are also present.
Influence of Mass Balance and Run-Off on Relief-Forming Activity of Mountain Glaciers
Authors: Chernova L. P.
Published: January 2011

Experimental data from several Soviet authors are used to investigate the importance of relief-forming processes in a glacial environment. Water discharge from glacial rivers was found to be crucial for the evolution of frontal moraines versus pro-glacial glaciofluvial deposits (sandar and valley trains).
An Ice-shelf Moraine, George VI Sound, Antarctica
Authors: Sugden D. E. , Clapperton C. M.
Published: January 2011

The morphology, sediments, and processes associated with the construction of a moraine along the western margin of the ice shelf in George VI Sound, Antarctica, are discussed. The moraine occurs as a double ridge where the ice sheet grounds against promontories on Alexander Island and is approximately horizontal over a distance of 120 km. It consists of exotic rock debris carried into the ice shelf by Antarctic Peninsula glaciers and local rock debris derived from the grounding line on Alexander Island. As the coast steepens, so the proportion of exotic rocks increases. The transport of basal material from the peninsula implies that there can be little bottom melting beneath this part of the ice shelf. The moraine is modified by streams and marginal lakes which periodically drain into and through the ice shelf. Tidal lakes are impounded against the ice shelf in shallower embayments and consist of fresh water overlying sea-water. A conceptual model of the moraine is developed and may help to explain some features of puzzling horizontal moraines found in formerly glaciated areas.
A Model for Sedimentation by Tidewater Glaciers
Authors: Powell Ross D.
Published: January 2011

Sampling of sediment from the fjord floor in front of tidewater glaciers in Glacier Bay, Alaska, has provided information about processes in this restricted glacimarine (Dreimanis 1979) setting. Sediment sampling, in conjunction with oceanographic and glacial dynamics data, has also enabled the discrimination of sediment types and their facies associations. Deposits are strongly controlled by: sea-water characteristics, position and sediment discharge of melt-water streams, iceberg calving, and rate of glacierfront retreat.

Five distinct facies associations have been found to reflect glacier-fjord regimes. The facies associations and ice-fjord conditions responsible for them form the basis for constructing a preliminary model for glacimarine sedimentation by tidewater glaciers. The model can be used to predict (i) rapid retreat of an actively calving ice front, (ii) slow retreat or stabilization of a calving ice front at a channel constriction, (iii) stabilization of a melting (very rarely calving) ice front when the glacier base is near tidewater elevation, and (iv) large outwash delta progradation into a fjord when the ice front retreats onto land. This model can be used to interpret facies associations found in a stratigraphic record.
Effect of Normal Pressure on Glacier Sliding (Abstract only)
Authors: Hooke Roger L.
Published: January 2011

Mercury is used to force a block of ice, measuring 0.20 ⨯ 0.45 m in area and 0.20 m in height, over an irregular bed. Normal and shear stresses on the bed can be varied up to 15 and 3 ⨯ 105 Pa respectively, so the apparatus permits a full-scale simulation of sliding of a 150 m thick glacier over irregularities a few tens of millimeters in height.

Preliminary results of an experiment in which ice slid over a bed consisting of two streamlined bumps, roughly 15 mm in height, suggest that sliding velocity is independent of normal pressure in the absence of cavitation. This is consistent with existing theoretical models of glacier sliding (Weertman 1964, Kamb 1970, Lliboutry 1979), but is not consistent with the experimental results of Budd and others (1979). Further studies are needed to determine the reasons for this disagreement.