bluuebunny/crossref_metadata_2025 huggingface dataset:
The Costs of Bankruptcy: Chapter 7 Liquidation versus Chapter 11 Reorganization
Authors: BRIS ARTURO , WELCH IVO , ZHU NING
Published: May 2006

Our paper explores a comprehensive sample of small and large corporate bankruptcies in Arizona and New York from 1995 to 2001. Bankruptcy costs are very heterogeneous and sensitive to the measurement method used. We find that Chapter 7 liquidations appear to be no faster or cheaper (in terms of direct expense) than Chapter 11 reorganizations. However, Chapter 11 seems to preserve assets better, thereby allowing creditors to recover relatively more. Our paper also provides a large number of further empirical regularities.
Capital Gains Tax Overhang and Price Pressure
Authors: JIN LI
Published: May 2006

I study whether the capital gains tax is an impediment to selling by some investors and if so, to what degree associated delayed selling affects stock prices. I find that selling decisions by institutions serving tax‐sensitive clients are sensitive to cumulative capital gains, a pattern not observed for institutions with predominantly tax‐exempt clients. Moreover, tax‐related underselling impacts stock prices during large earnings surprises for stocks held primarily by tax‐sensitive investors. The corresponding price reactions are less negative (more positive) with higher cumulative capital gains. This price pressure pattern is more severe when arbitrage is more costly.
Distance Constraints: The Limits of Foreign Lending in Poor Economies
Authors: MIAN ATIF
Published: May 2006

How far does mobility of multinational banks solve problems of financial development? Using a panel of 80,000 loans over 7 years, I show that greater cultural and geographical distance between a foreign bank's headquarters and local branches leads it to further avoid lending to “informationally difficult” yet fundamentally sound firms requiring relational contracting. Greater distance also makes them less likely to bilaterally renegotiate, and less successful at recovering defaults. Differences in bank size, legal institutions, risk preferences, or unobserved borrower heterogeneity cannot explain these results. These distance constraints can be large enough to permanently exclude certain sectors of the economy from financing by foreign banks.
Inter‐Court Dynamics and the Development of Legal Policy: Citation Patterns in the Decisions of the U.S. Courts of Appeals
Authors: Solberg Rorie Spill , Emrey Jolly A. , Haire Susan B.
Published: May 2006

Lower federal appellate judges, like other government officials, identify problems, formulate and implement solutions, and subsequently evaluate them for their efficacy. Immediately following the passage of the Americans with Disabilities Act, courts were confronted with cases that raised new policy issues in claims of employment discrimination. With no guidance from the Supreme Court for five years, circuit courts articulated solutions to these issues with written published opinions. By examining citations to precedents in those opinions, we evaluate the degree to which the court’s reasoning draws on policies from other circuits. Although stare decisis does not compel appeals court judges to consider decisions from other circuits, 76 percent of the opinions include a reference to an out‐of‐circuit precedent. Outside citations were not uniform across circuits and cases with increased references to outside courts in circuits were characterized by conflict. Our examination of citation patterns suggests that the development of precedent proceeds on two tracks. On one level, circuit judges’ opinions build on precedent from within their court. More broadly, citations reflect on an inter‐court dialog to identify conflict and consensus in federal legal policy.
Child Care Subsidies and Employment Behavior Among Very‐Low‐Income Populations in Three States
Authors: Ficano Carlena K. Cochi , Gennetian Lisa A. , Morris Pamela A.
Published: May 2006

Using merged administrative data from welfare reform evaluations in three states, we estimate the effects of child care subsidy use on the length of time it takes for a welfare applicant to move into substantial employment. Findings show that the use of a child care subsidy during an unemployed or marginally employed spell of welfare receipt is associated with between a 0.6 and 1.7 quarter (or 11% to 34%) reduction in the time to substantial employment in two of the three state samples. The positive influence of subsidy use on transitions to substantial employment is strongest for those welfare applicants with the lowest earnings who are mixing welfare and work prior to subsidy receipt.
The Impact of Child Care Subsidies on Single Mothers’ Work Effort
Authors: Crawford April
Published: May 2006

Access to affordable child care is a formidable barrier to employment for many families. Following passage of the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) in 1996, funding for child care assistance increased dramatically. Using data from the National Survey of America’s Families (NSAF), the impact of child care subsidies on single mother’s work effort is evaluated. The results indicate that not only are women more likely to be employed when they receive child care subsidies, they are also more likely to be employed full time. Single mothers who reported receiving assistance with child care worked, on average, 9.4 hours more per week than mother’s who did not receive help. While growth in funding for child care has slowed in recent years, findings like the ones presented here highlight the importance of affordable child care in the employment decisions of mothers with young children.
The Reversal of Favorable Child Living Arrangement Trends of the Late 1990s
Authors: Primus Wendell E.
Published: May 2006

During the late 1990s, there was a notable shift in child living arrangements toward two‐parent households and away from single parenthood. Whether due to economic factors, declining teen birth rates, welfare reform, or some other cultural cause or a combination of these factors, something happened in the 1990s that stabilized marriage rates and led to declines in single‐parent households. There was also considerable hope that the federal welfare reforms enacted in 1996 might be responsible for the change in these trends. However, since 2000, while the downward trend in teen births continues, the gains in percentage of children living with two parents have been virtually eliminated. This article carefully documents these recent trends, examines the relationship of recessions on child living arrangements, and concludes that it is impossible to disentangle the role of welfare reform from its broader economic, policy, and demographic context.
State TANF Spending: Predictors of State Tax Effort to Support Welfare Reform
Authors: Rodgers Harrell R. , Tedin Kent L.
Published: May 2006

State spending on Temporary Assistance to Needy Families (TANF) greatly varies. Combined federal and state spending by the states per TANF family or recipient reflects the historic level of state generosity for Aid to Families with Dependent Children (AFDC), the failure of the federal government to set any minimum spending standard for the states, and the failure of the federal government to adjust federal grants for huge changes in state TANF caseloads. Our multivariate analysis shows that state spending for TANF is greatly influenced by the percentage of the state population that is black, the percentage of the state population that is on TANF (especially if a significant percentage of the rolls consist of black recipients), and the economic conditions within the state. Some states spend as much as their economies will allow, while other states spend far below capacity. Despite the very different goals of TANF, state spending is still heavily influenced by their historic approach to AFDC.
Getting the Order Right: Child Support Guidelines and the Cost of Raising Children
Authors: Beld Jo Michelle
Published: May 2006

This article argues that the United States Department of Agriculture’s (USDA) estimates of parental expenditures on children are an appropriate economic foundation for state child support guidelines. The USDA’s estimates are consistent with the public policy purposes of state guidelines and may improve the extent to which they accomplish federal intent. The article examines the role of valid and reliable child cost estimates in advancing the policy objectives for child support, summarizes the theoretical and empirical challenges of estimating those costs, suggests the limitations of the most widely used estimation methods in relation to the policy purposes described earlier, and evaluates the USDA’s method in relation to those same purposes. The evidence suggests that guidelines based on the USDA’s estimates are more likely than the most commonly used estimates to yield adequate child support orders and to allocate economic responsibility for children appropriately among the custodial parent, the noncustodial parent, and the state.
Reductions in Poverty Significantly Greater in the 1990s Than Official Estimates Suggest
Authors: Primus Wendell E.
Published: May 2006

Any serious student of poverty understands the many weaknesses of the official poverty measure. In response to these concerns, the National Academy of Sciences issued recommendations to improve the official poverty measure. In addition, the Census Bureau has undertaken a vast amount of research to improve our official poverty series. The methodology used in this analysis incorporates as many of those recommendations as possible to examine the change in poverty from 1979 to 2000. Compared to this methodology, the official poverty measure understates dramatically the reduction in poverty over time.
The parasitoid Gonatopus bartletti reduces presence of plant‐pathogenic Spiroplasma kunkelii within the leafhopper vector Dalbulus maidis
Authors: Moya‐Raygoza Gustavo , Palomera‐Avalos Verónica , Chacón‐Torres Nubia M. , Becerra‐Chiron Iskra M.
Published: May 2006

Homopteran vectors (e.g., leafhoppers) of plant pathogens are vessels for reproduction of cell wall‐free bacteria. These vectors also serve as hosts for larval parasitoid dipterans, hymenopterans, and strepsipterans. However, no study has explored the relationship among these wall‐free bacteria and parasitoid larvae within the insect host. We studied the corn stunt spiroplasma (CSS), Spiroplasma kunkelii Whitcomb (Mycoplasmatales: Spiroplasmataceae), a bacterium that originated from secondary symbionts that cause corn stunt disease in maize, Zea mays L., and its reproduction in the haemolymph of the corn leafhopper, Dalbulus maidis (Delong and Wolcott) (Homoptera: Cicadellidae). We also studied the dryinid parasitoid Gonatopus bartletti Olmi (Hymenoptera: Dryinidae), the larva of which feeds in the corn leafhopper haemolymph. Our results showed that when CSS and the wasp coexisted in D. maidis, the development of the parasitoid was not affected by S. kunkelii. Parasitoid development was successfully completed when leafhoppers acquired S. kunkelii before or after parasitism and when CSS had median (10 days) and long (20 days) incubation periods in the leafhopper before parasitization. The presence of S. kunkelii did not affect parasitoid development to the adult stage. However, polymerase chain reaction showed that the presence (survival) of S. kunkelii in the leafhopper was negatively affected by the parasitoid larva. Fewer leafhoppers had CSS before and after parasitization compared with leafhoppers that only acquired the CSS. This negative effect helps to explain the high parasitism rate by G. bartletti in D. maidis and the low presence of S. kunkelii in the corn leafhopper when CSS and the wasp parasitoid overlap throughout their geographic distribution. The parasitoid larva may negatively affect S. kunkelii by (1) producing antibacterial peptides that are toxic to CSS; (2) producing teratocytes that take nutrients from the host for larval development, but these nutrients are required by CSS; (3) affecting, indirectly, CSS through other symbiotic microorganisms; and (4) producing proteins with antibacterial activity that are present in the venom of the wasp parasitoid.
Field superparasitism by Phymastichus coffea, a parasitoid of adult coffee berry borer, Hypothenemus hampei
Authors: Jaramillo Juliana , Borgemeister Christian , Setamou Mamoudou
Published: May 2006

Superparasitism by Phymastichus coffea LaSalle (Hymenoptera: Eulophidae), a parasitoid of adults of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), was recorded under field conditions in a coffee plantation in Colombia. Parasitoid adults were released 1, 5, and 9 days after artificial infestations of 90‐, 150‐, and 210‐day‐old coffee berries with H. hampei females. The position of the beetle inside the berry and the number of P. coffea larvae per female host were assessed 10 days after each parasitoid release. Under laboratory conditions, P. coffea usually lays two eggs per host, one female and one male. In our studies, we often recorded more than six P. coffea larvae in an individual host and mean numbers of larvae per host ranged from two to 4.45. Superparasitism by P. coffea under field conditions was influenced by the age of the coffee berries, which is the most important factor determining the speed of penetration by H. hampei, and therefore the time the beetles are exposed to a P. coffea attack. The number of parasitoid larvae in each H. hampei female gradually decreased with the age of the berry, and also linearly decreased with the time of parasitoid release. Age‐dependent effects of coffee berries that alter the ratio of available hosts to searching parasitoids by providing refuges to the herbivore, largely determine the extent of superparasitism of H. hampei by P. coffea under fields conditions in Colombia.
Does nitrogen limitation promote intraguild predation in an aphidophagous ladybird?
Authors: Kagata H. , Katayama N.
Published: May 2006

Reciprocal intraguild predation occurs between the two aphidophagous ladybird beetles Coccinella septempunctata L. and Harmonia axyridis Pallas (Coleoptera: Coccinellidae). However, its direction is asymmetrical; H. axyridis generally acts as an intraguild predator, and C. septempunctata as an intraguild prey. According to Denno and Fagan's prediction that nitrogen shortages in predators may promote intraguild predation, it was hypothesized that growth of intraguild predator H. axyridis is more limited by nitrogen than that of intraguild prey C. septempunctata, and that H. axyridis growth is enhanced by feeding on C. septempunctata compared to feeding on aphids.

To determine nitrogen‐limited growth in H. axyridis, the following two predictions were examined. First, it was predicted that the nitrogen content of H. axyridis would be higher than that of C. septempunctata when both feed on aphids. However, nitrogen content did not differ between the two ladybirds. Second, it was predicted that nitrogen‐use efficiency of H. axyridis would be lower than that of C. septempunctata. However, there was no significant difference between species. These results did not support the hypothesis that growth of H. axyridis is more limited by nitrogen than that of C. septempunctata. In addition, the present study showed that dry mass and nitrogen growth of H. axyridis were not enhanced, but rather decreased, by eating high‐nitrogen C. septempunctata, compared to eating low‐nitrogen aphids. Overall, the present study did not support the hypothesis that nitrogen shortages in predators may promote intraguild predation.
Dispersion theory and the sterile insect technique: application to two species of fruit fly
Authors: Meats A. , Smallridge C.J. , Dominiak B.C.
Published: May 2006

Dispersion theory is applied to the distribution of two kinds of sterile insect, Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), and Queensland fruit fly (Qfly), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Dispersion theories are an essential basis of sampling theory and sampling plans, but this paper looks at them from another direction and uses data from arrays of sterile insect technique (SIT) monitoring traps to compare the utility of different measures such as coefficient of variation (CV), the exponent b of Taylor's power law, and exponent k of the negative binomial distribution and also derives predictions pertaining to the density (and hence release rate) of sterile insects that would be required to achieve effective coverage of the target area. This is far more useful than reliance on just the mean values of trap catches because such reliance takes no account of the fact that sterile flies distribute themselves unevenly with many patches inadequately covered despite the impression given by the mean. Data were used from recapture rates following either ‘roving releases’ of Medfly or releases from fixed points of Qfly. The relation of recapture rate to CV indicated that a doubling of release rate in order to double average recapture rate from 150 per trap per week to a value of 300 would have very little effect in terms of reducing CV and that there appears to be no practical prospect of reducing CV to below unity with the current methods of release without incurring a manifold increase in cost. Similarly, models derived from the negative binomial equation indicated that a law of diminishing returns applies in terms of the increase in the amount of adequate coverage (such as the percentage of traps catching >50 flies per week) that can be obtained by increasing release rates.
The effect of ageing on retinal nerve fibre layer thickness: an evaluation by scanning laser polarimetry with variable corneal compensation
Authors: Da Pozzo Stefano , Iacono Pierluigi , Marchesan Roberta , Minutola Daniela , Ravalico Giuseppe
Published: May 2006

Purpose:  To evaluate whether a significant age‐related thinning of the retinal nerve fibre layer (RNFL) is measurable by means of scanning laser polarimetry with variable corneal compensation (GDx‐VCC) in a sample of healthy eyes.

Methods:  A sample of 324 eyes of 324 healthy subjects (mean age 56 ± 14 years, range 21–85 years) underwent a complete ophthalmic evaluation, standard automated perimetry and RNFL scan with the GDx‐VCC. Temporal‐superior‐nasal‐inferior‐temporal (TSNIT), superior and inferior average (SA and IA) values provided on the printout were collected and their mean value averaged from all eyes and also after separating the eyes by gender and by age decades. The values of the three parameters were plotted against age and linear regression was calculated.

Results:  Ageing is associated with a significant RNFL thinning (0.08 µ, 0.16 µ and 0.12 µ per year for TSNIT, SA and IA, respectively; p < 0.001). Analysis showed a similar association with age decade (p < 0.001 on anova). For the TSNIT average, a 9.5% thinning from baseline values was estimated for a 65‐year lifespan. Corresponding values for SA and IA were 16.2% and 11.7%, respectively.

Conclusions:  Analysis by GDx‐VCC confirmed previous reports about significant age‐related RNFL thinning. However, a lower rate per year was found, probably because GDx‐VCC measurements are much more reliable than those obtained with the previous generation of polarimeters.
Ocular angiogenesis: the role of growth factors
Authors: Kvanta Anders
Published: May 2006

Ocular angiogenesis, the formation of new vessels from the existing vascular tree, is a major cause of severe vision loss. It can affect different structures in the eye, including the retina, choroid and cornea. During the last decade our knowledge in the mechanisms underlying ocular angiogenesis has increased dramatically. We have witnessed the identification of key molecules. Many are classified as growth factors due to their biological properties, regulating angiogenesis. This knowledge has propelled the development of a new group of therapeutic tools, the antiangiogenic agents. This review gives an update on the role of growth factors in ocular angiogenesis from both a basic and a clinical perspective.
Novel clinical application of sterilized, freeze‐dried amniotic membrane to treat patients with pterygium
Authors: Nakamura Takahiro , Inatomi Tsutomu , Sekiyama Eiichi , Ang Leonard P. K. , Yokoi Norihiko , Kinoshita Shigeru
Published: May 2006

Purpose:  To evaluate the use of sterilized, freeze‐dried amniotic membrane (FD‐AM) transplantation for pterygium surgery.

Methods:  This study involved a prospective, non‐comparative, interventional case series. Thirteen eyes of 13 patients with primary (eight eyes) or recurrent (five eyes) pterygium were studied. After excision of the pterygium fibrous tissues and application of intraoperative use of mitomycin‐C, sterilized FD‐AM was sutured over the bare scleral defect. The integrity of the FD‐AM graft, epithelialization over the FD‐AM, pterygium recurrence and postoperative complications were evaluated.

Results:  Postoperatively, the FD‐AM was well retained in all patients, and complete epithelialization over the transplanted membrane was achieved within 1–2 weeks. All patients demonstrated early resolution of ocular inflammation and there was no recurrence of pterygium in any of the treated patients during the mean follow‐up of 13.9 ± 6.0 months. No ocular complications were noted following transplantation.

Conclusion:  Sterilized FD‐AM showed excellent biocompatibility on the human ocular surface. This novel and promising biomaterial may be a useful alternative to conjunctival grafting in the treatment of pterygium.
The discovery of the human melanocyte
Authors: Westerhof Wiete
Published: May 2006

Around 2200 bc the first written description of a human pigmentation disorder, most likely vitiligo, was recorded, and from that moment the history of research into human pigmentation can be traced. For the following 4000 yr, the origins of human skin colour remained an enigma that was to generate a multitude of misconceptions. Even after European physicians began to dissect and compare dark and light coloured skin to reveal its underlying anatomy, the origins of skin and hair pigmentation were a matter of frequently erroneous speculation. The true source of human pigmentation was only finally revealed with the discovery of the melanocyte in the 19th century. Once tyrosinase was identified to be the key enzyme in pigment formation, attention focused on elucidating the chemical structure of melanin, an enterprise that remains incomplete. The developmental origins of the melanocyte were described from 1940 to 1960, and the concept of the epidermal melanin unit was introduced together with a description of the ultrastructure of the melanosome and melanosome transfer. With these advances came the realization that different skin types exhibit distinct differences at the histological level that relate to varying amounts of eumelanin and pheomelanin produced by the melanocytes. The foundation established over the past 4000 yr is the basis for all current research into this fascinating cell type.
Identification of the osteoprotegerin/receptor activator of nuclear factor‐kappa B ligand system in gingival crevicular fluid and tissue of patients with chronic periodontitis
Authors: Lu H.‐K. , Chen Y.‐L. , Chang H.‐C. , Li C.‐L. , Kuo M. Y.‐P.
Published: May 2006

Background and Objective:  Recent findings have suggested that osteoclastogenesis is directly regulated by receptor activator of nuclear factor‐kappa B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG). However, no studies have described interactions of OPG/RANKL and the gp130 cytokine family in periodontal disease. This study aimed to identify and quantify OPG/RANKL in the gingival crevicular fluid (GCF) and connective tissue of patients with periodontitis, and to clarify possible correlations with disease severity and interleukin‐6 (IL‐6) cytokines.

Material and Methods:  Ninety‐five sites in 20 patients with generalized chronic periodontitis were divided into four groups by site based on probing depth (PD) and bleeding on probing (BOP). In periodontitis patients, GCF was obtained using sterile paper strips from clinically healthy sites (PD ≤ 3 mm without BOP, n = 12 in periodontitis subjects), mildly diseased sites (PD ≤ 3 mm with BOP, n = 23), moderately diseased sites (PD ≤ 4–6 mm with BOP, n = 33) and severely diseased sites (PD > 6 mm with BOP, n = 27). Fourteen clinically healthy sites from four periodontally healthy individuals were used as the control group. The levels of OPG, RANKL and two gp130 cytokines – IL‐6 and oncostatin M (OSM) – in the GCF were determined by an enzyme‐linked immunosorbent assay (ELISA) and are expressed as total amounts (pg/site). Immunohistochemical localization of OPG‐ and RANKL‐positive cells was also performed on gingival connective tissues harvested from patients with periodontitis (inflammatory group, n = 8 biopsies) and from non‐diseased individuals (healthy group, n = 8 biopsies).

Results:  GCF RANKL, but not OPG, was elevated in diseased sites of patients with periodontitis. However, the expressions of OPG and RANKL showed no correlation with disease severity (r = 0.174 and 0.056, respectively), but the content of RANKL in the GCF was significantly positively correlated with those of IL‐6 (r = 0.207) and OSM (r = 0.231) (p < 0.01). Immunohistochemical staining showed that RANKL‐positive cells were significantly distributed in the inflammatory connective tissue zone of diseased gingiva, compared with those of samples from non‐diseased persons (p < 0.01). However, few OPG‐positive cells were found in connective tissue zones of either the diseased gingiva or healthy biopsies.

Conclusion:  These findings imply that in this cross‐sectional study of GCF, RANKL, IL‐6 and OSM were all prominent in periodontitis sites, whereas OPG was inconsistently found in a few samples of diseased sites but was undetectable in any of the control sites. The results also imply that the expression of RANKL was positively correlated with IL‐6 and OSM in the GCF.
Vaginal Nitric Oxide in Pregnant Women with Bacterial Vaginosis
Authors: Genç Mehmet R. , Delaney Mary L. , Onderdonk Andrew B. , Witkin Steven S. ,   the Microbiology and Prematurity (MAP) Study Group
Published: May 2006

Problem

To evaluate vaginal nitric oxide (NO) production in response to alterations in the vaginal microbial flora.

Method of study

Cervicovaginal lavage samples from 206 women at 18–22 weeks of gestation were tested for NO, interleukin‐1β (IL‐1β), IL‐1 receptor antagonist (IL‐1ra), tumor necrosis factor‐α and the inducible 70 kDa heat shock protein (hsp70). Bacterial vaginosis (BV) was diagnosed based on gram staining of vaginal smears.

Results and conclusions

Elevated NO (>2.14 mmol/L) was associated with a diagnosis of BV (38% versus 11%, P < 0.008) as well as an increased median vaginal IL‐1ra concentration (72.5 ng/ml versus 36.6 ng/ml, P = 0.041). Elevated vaginal NO was also associated with vaginal hsp70 and this relationship was independent of BV status or IL‐1ra concentrations (P < 0.026). We conclude that vaginal hsp70 release in response to abnormal vaginal microflora may trigger NO production in an attempt to minimize the pathological consequences of this altered milieu.
Human Oviductal Stromal Fibroblasts, But Not Oviductal Epithelial Cells, Express Toll‐Like Receptor 4: The Site‐Specific Mucosal Immunity of the Human Fallopian Tube against Bacterial Infection
Authors: Itoh Hiroko , Nasu Kaei , Nishida Masakazu , Matsumoto Harunobu , Yuge Akitoshi , Narahara Hisashi
Published: May 2006

Problem

To evaluate the site‐specific immunoregulatory mechanisms against bacterial infection in the human fallopian tubes.

Method of Study

We investigated the effects of lipopolysaccharide (LPS) on the production of CXC chemokines by cultured oviductal epithelial cells (OEC) and oviductal stromal fibroblasts (OSF). The expression of Toll‐like receptor (TLR) 4 and CD14 protein in OEC and OSF were evaluated. The phosphorylation of the inhibitor κB‐α (IκB‐α) protein after LPS stimulation was also examined.

Results

Lipopolysaccharide stimulated the secretion of granulocyte chemotactic protein‐2, growth‐regulated oncogene‐α, and epithelial neutrophil activating peptide‐78 by OSF, but not by OEC. The phosphorylation of the IκB‐α protein was not detected in OEC after stimulation by LPS, whereas IκB‐α phosphorylation was observed in OSF after stimulation by LPS. The expression of the TLR4 protein and mRNA was detected only in OSF but not in OEC. The expression of CD14 was not detected in either OEC or OSF.

Conclusion

These results suggest that epithelial cells and fibroblasts in the human fallopian tube have evolved a unique, site‐specific mechanism for recognizing Gram‐negative pathogens. The lack of TLR4 in OEC may be important for avoiding a state of unnecessary inflammation that could disrupt the epithelial barrier and cause irreversible tubal scarring.
Granulocyte‐Macrophage Colony‐Stimulating‐Factor Increases Interferon‐τ Protein Secretion in Bovine Trophectoderm Cells
Authors: Michael Donna D. , Wagner Sara K. , Ocón Olga M. , Talbot Neil C. , Rooke John A. , Ealy Alan D.
Published: May 2006

Problem

Uterine‐derived factors are required for optimal conceptus development and secretion of the maternal recognition of pregnancy factor, interferon‐τ (IFN‐τ). Identifying these factors may lead to the development of schemes for increasing pregnancy success in cattle.

Method of Study

The objectives were to examine the effects of granulocyte‐macrophage colony‐stimulating‐factor (GM‐CSF) on trophectoderm proliferation rates and IFN‐τ production, and verify the appropriateness of using an in vitro model of bovine trophectoderm (CT‐1 cell).

Results

Rate of [3H]‐thymidine incorporation into DNA was increased by supplementation of CT‐1 medium with 10 or 100 ng/mL porcine (po) GM‐CSF. GM‐CSF supplementation to CT‐1 medium also increased IFN‐τ secretion. When results were normalized to account for number of CT‐1 cells, 10 and 100 ng/mL poGM‐CSF increased antiviral activity and IFN‐τ concentrations (using an IFN‐τ‐specific enzyme‐linked immunosorbent assay) in CT‐1 conditioned medium compared with controls.

Conclusions

These findings indicate that GM‐CSF increases proliferation and IFN‐τ production in bovine trophectoderm.
Soluble HLA‐G Molecules Induce Apoptosis in Natural Killer Cells
Authors: Lindaman Amy , Dowden Amy , Zavazava Nicholas
Published: May 2006

Membrane‐bound human leukocyte antigen‐G (HLA‐G) molecules are primarily expressed by cytotrophoblasts of the fetus. They are thought to protect the fetus from immunologic attack by the maternal immune system and have recently been associated with transplantation graft acceptance. In addition, soluble HLA‐G molecules (sHLA‐G) have been shown to play a role in the success of pregnancies, but are upregulated in certain cancers. However, the exact mechanism for this regulation has remained elusive. The aim of this study was to examine the mechanism by which sHLA‐G interact with natural killer (NK) cells in vitro. sHLA‐G effectively blocked NK lysis of target cells via fracticide killing of NK cells by apoptosis. These studies support the protective role of sHLA‐G in immunologic reactions by interacting with NK cells, thus providing a regulatory function.
Extraenzymatic functions of the dipeptidyl peptidase IV‐related proteins DP8 and DP9 in cell adhesion, migration and apoptosis
Authors: Yu Denise M. T. , Wang Xin M. , McCaughan Geoffrey W. , Gorrell Mark D.
Published: May 2006

The dipeptidyl peptidase IV gene family contains the four peptidases dipeptidyl peptidase IV, fibroblast activation protein, dipeptidyl peptidase 8 and dipeptidyl peptidase 9. Dipeptidyl peptidase IV and fibroblast activation protein are involved in cell–extracellular matrix interactions and tissue remodeling. Fibroblast activation protein is upregulated and dipeptidyl peptidase IV is dysregulated in chronic liver disease. The effects of dipeptidyl peptidase 8 and dipeptidyl peptidase 9 on cell adhesion, cell migration, wound healing and apoptosis were measured by using green fluorescent protein fusion proteins to identify transfected cells. Dipeptidyl peptidase 9‐overexpressing cells exhibited impaired cell adhesion, migration in transwells and monolayer wound healing on collagen I, fibronectin and Matrigel. Dipeptidyl peptidase 8‐overexpressing cells exhibited impaired cell migration on collagen I and impaired wound healing on collagen I and fibronectin in comparison to the green fluorescent protein‐transfected controls. Dipeptidyl peptidase 8 and dipeptidyl peptidase 9 enhanced induced apoptosis, and dipeptidyl peptidase 9 overexpression increased spontaneous apoptosis. Mechanistic investigations showed that neither the catalytic serine of dipeptidyl peptidase 8 or dipeptidyl peptidase 9 nor the Arg‐Gly‐Asp integrin‐binding motif in dipeptidyl peptidase 9 were required for the impairment of cell survival, cell adhesion or wound healing. We have previously shown that the in vitro roles of dipeptidyl peptidase IV and fibroblast activation protein in cell–extracellular matrix interactions and apoptosis are similarly independent of catalytic activity. Dipeptidyl peptidase 9 overexpression reduced β‐catenin, tissue inhibitor of matrix metalloproteinases 2 and discoidin domain receptor 1 expression. This is the first demonstration that dipeptidyl peptidase 8 and dipeptidyl peptidase 9 influence cell–extracellular matrix interactions, and thus may regulate tissue remodeling.
Mutant recombinant serpins as highly specific inhibitors of human kallikrein 14
Authors: Felber Loyse M. , Kündig Christoph , Borgoño Carla A. , Chagas Jair R. , Tasinato Andrea , Jichlinski Patrice , Gygi Christian M. , Leisinger Hans‐Jürg , Diamandis Eleftherios P. , Deperthes David , Cloutier Sylvain M.
Published: May 2006

The reactive center loop (RCL) of serpins plays an essential role in the inhibition mechanism acting as a substrate for their target proteases. Changes within the RCL sequence modulate the specificity and reactivity of the serpin molecule. Recently, we reported the construction of α1‐antichymotrypsin (ACT) variants with high specificity towards human kallikrein 2 (hK2) [Cloutier SM, Kündig C, Felber LM, Fattah OM, Chagas JR, Gygi CM, Jichlinski P, Leisinger HJ & Deperthes D (2004) Eur J Biochem271, 607–613] by changing amino acids surrounding the scissile bond of the RCL and obtained specific inhibitors towards hK2. Based on this approach, we developed highly specific recombinant inhibitors of human kallikrein 14 (hK14), a protease correlated with increased aggressiveness of prostate and breast cancers. In addition to the RCL permutation with hK14 phage display‐selected substrates E8 (LQRAI) and G9 (TVDYA) [Felber LM, Borgoño CA, Cloutier SM, Kündig C, Kishi T, Chagas JR, Jichlinski P, Gygi CM, Leisinger HJ, Diamandis EP & Deperthes D (2005) Biol Chem386, 291–298], we studied the importance of the scaffold, serpins α1‐antitrypsin (AAT) or ACT, to confer inhibitory specificity. All four resulting serpin variants ACTE8, ACTG9, AATE8 and AATG9 showed hK14 inhibitory activity and were able to form covalent complex with hK14. ACT inhibitors formed more stable complexes with hK14 than AAT variants. Whereas E8‐based inhibitors demonstrated a rather relaxed specificity reacting with various proteases with trypsin‐like activity including several human kallikreins, the two serpins variants containing the G9 sequence showed a very high selectivity for hK14. Such specific inhibitors might prove useful to elucidate the biological role of hK14 and/or its implication in cancer.
Processing, catalytic activity and crystal structures of kumamolisin‐As with an engineered active site
Authors: Okubo Ayumi , Li Mi , Ashida Masako , Oyama Hiroshi , Gustchina Alla , Oda Kohei , Dunn Ben M. , Wlodawer Alexander , Nakayama Toru
Published: May 2006

Kumamolisin‐As is an acid collagenase with a subtilisin‐like fold. Its active site contains a unique catalytic triad, Ser278‐Glu78‐Asp82, and a putative transition‐state stabilizing residue, Asp164. In this study, the mutants D164N and E78H/D164N were engineered in order to replace parts of the catalytic machinery of kumamolisin‐As with the residues found in the equivalent positions in subtilisin. Unlike the wild‐type and D164N proenzymes, which undergo instantaneous processing to produce their 37‐kDa mature forms, the expressed E78H/D164N proenzyme exists as an equilibrated mixture of the nicked and intact forms of the precursor. X‐ray crystallographic structures of the mature forms of the two mutants showed that, in each of them, the catalytic Ser278 makes direct hydrogen bonds with the side chain of Asn164. In addition, His78 of the double mutant is distant from Ser278 and Asp82, and the catalytic triad no longer exists. Consistent with these structural alterations around the active site, these mutants showed only low catalytic activity (relative kcat at pH 4.0 1.3% for D164N and 0.0001% for E78H/D164N). pH‐dependent kinetic studies showed that the single D164N substitution did not significantly alter the logkcat vs. pH and log(kcat/Km) vs. pH profiles of the enzyme. In contrast, the double mutation resulted in a dramatic switch of the logkcat vs. pH profile to one that was consistent with catalysis by means of the Ser278‐His78 dyad and Asn164, which may also account for the observed ligation/cleavage equilibrium of the precursor of E78H/D164N. These results corroborate the mechanistic importance of the glutamate‐mediated catalytic triad and oxyanion‐stabilizing aspartic acid residue for low‐pH peptidase activity of the enzyme.
Land‐use History Affects the Distribution of the Saprophytic Orchid Wullschlaegelia calcarata in Puerto Rico's Tabonuco Forest1
Authors: Bergman Erin , Ackerman James D. , Thompson Jill , Zimmerman Jess K.
Published: May 2006

Human activities such as logging and agriculture can severely damage forest ecosystems by changing forest structure, ecosystem function, and biodiversity. These changes may have long‐lasting consequences, which influence forest recovery. We investigated the effect of past human disturbance on the current distribution of an understory, achlorophyllous orchid, Wullschlaegelia calcarata in Puerto Rico's tropical rain forest after 70 yr of recovery. Our study site was the 16‐ha Luquillo Forest Dynamics Plot located in the Luquillo Experimental Forest, which has four areas with differing intensity of land use that have been distinguished from variation in canopy cover seen in aerial photographs taken in 1936. We recorded orchids in six 10‐m‐wide, 500‐m‐long transects across four different areas of land‐use history. We found that the orchid was not present in an area of the plot which had <20 percent canopy cover in 1936, and was most abundant in the area with >80 percent canopy cover, which had been minimally impacted by human activity. Tree species composition varied among land‐use history areas, and our observations suggested that this variation might be influencing the local distribution of W. calcarata. We also measured leaf litter biomass and identified the leaves of litter in areas with and without the orchid. Litter with a high proportion of Buchenavia tetraphylla leaves had more orchids. Even though human disturbance ceased in 1932, land‐use history in the Luquillo Forest still casts a shadow over the distribution of W. calcarata.
Nutrient Limitation in a Fire‐derived, Nitrogen‐rich Hawaiian Grassland1
Authors: D'Antonio Carla M. , Mack Michelle C.
Published: May 2006

Grasslands created by grass invasions into shrublands or woodlands followed by fire are now a dominant feature of many seasonally dry environments. In Hawaii Volcanoes National Park, introduced perennial grasses dominate grasslands created by fire in grass‐invaded woodlands. In a previous study, we found that net primary production in these grasslands is substantially lower than in unburned woodlands. Yet, our estimates of annual net nitrogen (N) mineralization showed higher rates in these savannas than in the unburned woodlands, rates that appear to greatly exceed annual N demand by the vegetation. We therefore hypothesized that N should not be limited to the plants growing in these sites. We tested this hypothesis with a 2‐yr fertilization experiment. At peak biomass, we found a 30 percent increase in live biomass in plots with N added and no increase in production with only phosphorus (P) added. N and P together were synergistic, suggesting that co‐limitation or P limitation becomes important when N is more available. Plants responded to added N by increasing individual leaf area and shoot length by over 50 percent. Tissue N was higher with added N; hence, biomass N was substantially higher. Tissue P concentrations declined with N addition but were elevated by P addition despite lack of a growth response to P alone. Overall, N limitation exists despite high annual rates of net N mineralization, and co‐limitation of production by P may occur when N is abundant. Here, asynchrony between plant nutrient demand and N availability may contribute to N limitation.
Resolution of MRS Applied to the Characterization of Hard‐Rock Aquifers
Authors: Legchenko Anatoly , Descloitres Marc , Bost Adelphe , Ruiz Laurent , Reddy Mohan , Girard Jean‐François , Sekhar Muddu , Mohan Kumar M.S. , Braun Jean‐Jacques
Published: May 2006

The performance of the Magnetic Resonance Sounding (MRS) method applied to the investigation of heterogeneous hard‐rock aquifers was studied. It was shown using both numerical modeling and field measurements that MRS could be applied to the investigation of the weathered part of hard‐rock aquifers when the product of the free water content multiplied by the thickness of the aquifer is >0.2 (for example, 10‐m‐thick layer with a 2% water content). Using a currently available one‐dimensional MRS system, the method allows the characterization of two‐dimensional subsurface structures with acceptable accuracy when the size of the subsurface anomaly is equal to or greater than the MRS loop. However, the fractured part of hard‐rock aquifers characterized by low effective porosity (<0.5%) cannot be resolved using currently available MRS equipment. It was found that shallow water in the weathered part of the aquifer may screen MRS signals from deeper water‐saturated layers, thus further reducing the possibility of investigating deeper fractured aquifers. A field study using the NUMISplus MRS system developed by IRIS Instruments was carried out on an experimental watershed in southern India. A heterogeneous unconfined aquifer in a gneissic formation was successfully localized, and MRS results were confirmed by drilling shortly after the geophysical study. The top of the aquifer revealed by MRS was found to be in a good agreement with observed static water level measurements in boreholes.
The Influence of Well Hydraulics on the Spatial Distribution of Well Incrustations
Authors: Houben Georg J.
Published: May 2006

In many cases, the operation of wells is hampered by the formation of mineral incrustations. From field studies, it is known that the distribution of incrustations in wells is quite inhomogeneous. Flow models were calculated to assess the hydraulic background of this phenomenon. For horizontal flow, the screen section facing the natural flow direction receives the majority of the total inflow. This phenomenon increases with increasing natural gradients of flow. The vertical distribution of water intake is also quite inhomogeneous. In partially penetrating wells, the uppermost part of the screen receives much more inflow than the deeper screen sections. These flow inhomogenities involve elevated flow velocities and may cause increased influx of shallow, oxygenated water, all conditions favorable for incrustation growth. Field investigations on incrusting wells clearly show that the identified screen areas of elevated flow are indeed much more prone to incrustation deposition. Such sections require more attention during rehabilitations. A suction flow control device can help to homogenize the inflow but can cause elevated entrance loss when affected by incrustation buildup itself.
Dealing with Fear: Implementing the Bush Doctrine of Preemptive Attack
Authors: Dockrill Saki Ruth
Published: May 2006

In the wake of the 9/11 terrorist attacks on the United States, the Bush Administration enunciated the doctrine of preemption, and implemented it by attacking Saddam Hussein’s Iraq. This article examines the dilemmas posed by the strategy of preemption and discusses how the Iraq war has so far failed to meet the test of legitimacy. It argues that the Iraq experience has weakened U.S. power, set back liberal internationalism, and placed the United States and its allies on the defensive in dealing with terrorists who espouse radical Islam, and with the volatile politics of the Middle East.
The Perfect Intelligence Failure? U.S. Pre‐War Intelligence on Iraqi Weapons of Mass Destruction
Authors: Phythian Mark
Published: May 2006

Prewar U.S. intelligence suggested that Saddam possessed weapons of mass destruction. None were found in Iraq. The threat they posed proved to be illusory and not imminent. Was Iraq a case of intelligence failure? In his seminal 1978 study of the inevitability of intelligence failure, Richard Betts argued that the most crucial mistakes are most often made by decision‐making consumers. Through analyses of the findings of the reports of the 2004 Senate Select Committee on Intelligence and President Bush’s Commission on the Intelligence Capabilities of the United States Regarding Weapons of Mass Destruction, this article finds failures occurring at numerous points across the intelligence cycle including, despite the conclusions of these two inquiries, the policy‐maker level. Although issues surrounding these shortcomings remain keenly contested and a full explanation will only be possible once the role of policy makers has been scrutinized, the analysis provides a rare window through which analysts may better understand the dynamics of intelligence failure.
The Ethics of Secession and Postinvasion Iraq
Authors: Moore Margaret
Published: May 2006

This article outlines the two central theories in the ethics of secession and examines whether or under what conditions these normative theories would be satisfied in a post-invasion Iraq. I argue that the two dominant normative theories of secession focus on the secessionist group, which national self-determination theories conceive as a nation holding a right to self-determination, and just-cause theories conceive as having a remedial right to secession as a victim of injustice. The Iraq case suggests that this is a flawed way of thinking about the issue. I argue that secession is more legitimate when fair multinational arrangements are not on offer; and that the fairness requirement involves examining constitutional arrangements from the point of view of all groups.
Spatial Localizations of Mam22 and Mam12 in the Magnetosomes of
Magnetospirillum magnetotacticum
Authors: Taoka Azuma , Asada Ryuji , Sasaki Hideaki , Anzawa Kazushi , Wu Long-Fei , Fukumori Yoshihiro
Published: May 2006

Magnetospirillum magnetotacticum
possesses intracellular magnetite particles with a chain-like structure, termed magnetosomes. The bacterium expresses 22-kDa and 12-kDa magnetosome-associated proteins, termed Mam22 (MamA) and Mam12 (MamC), respectively. In this study, we investigated the structure of the purified magnetosomes with transmission electron microscopic techniques and found that the magnetosomes consisted of four compartments, i.e., magnetite crystal, magnetosomal membrane, interparticle connection, and magnetosomal matrix. Furthermore, we determined the precise localizations of Mam22 and Mam12 using immunogold staining of the purified magnetosomes and ultrathin sections of the bacterial cells. Interestingly, most Mam22 existed in the magnetosomal matrix, whereas Mam12 was strictly localized in the magnetosomal membrane. Moreover, the recombinant Mam22 was attached to the magnetosomal matrix of the Mam22-deficient magnetosomes prepared by alkaline treatment, such as 0.1 M Caps-NaOH buffer (pH 11.0). The spatial localization of the magnetosome-associated proteins in the magnetosomal chain provides useful information to elucidate the functional roles of these proteins.