bluuebunny/crossref_metadata_2025 huggingface dataset:
IKBL promoter polymorphism is strongly associated with resistance to type 1 diabetes in Japanese
Authors: Yamashita T. , Hamaguchi K. , Kusuda Y. , Kimura A. , Sakata T. , Yoshimatsu H.
Published: February 2004

Abstract: Type 1 diabetes is a multifactorial disease in which the genes of the major histocompatibility complex (MHC) play a key role. Recently, non‐human leukocyte antigen (non‐HLA) genes in the class III region of this complex have been presumed to be associated with type 1 diabetes by linkage analyses. We investigated the possibility of the inhibitor of κB‐like (IKBL, also known as ‘NFKBIL1’) gene as one of these candidates. We carried out a case‐control study of 124 patients with type 1 diabetes and 330 healthy control subjects. The haplotypes of the IKBL promoter, i.e., PA (−263A, −63T), PB (−263A, −63A), PC (−263G, −63T), were assigned by the single‐nucleotide polymorphisms at positions −263 and −63 from the transcription start site. The frequency of the wild‐type haplotype, PA, was elevated, while that of the variant‐type haplotype, PC, was lower in patients than controls. In two‐locus analyses with HLA‐DRB1 alleles, the PA haplotype showed linkage disequilibrium with the DRB1*0405 allele and the PC haplotype with the DRB1*1502 allele. A notable observation was that the PC haplotype was significantly associated with protection in the DRB1*1502‐negative population. Our study indicates the first evidence of a possible independent association between type 1 diabetes and polymorphisms in the promoter of the IKBL gene.
Genes in the HLA class I region may contribute to the HLA class II‐associated genetic susceptibility to multiple sclerosis
Authors: Harbo H.F. , Lie B.A. , Sawcer S. , Celius E.G. , Dai K.‐Z. , Oturai A. , Hillert J. , Lorentzen Å.R. , Laaksonen M. , Myhr K.‐M. , Ryder L.P. , Fredrikson S. , Nyland H. , Sørensen P.S. , Sandberg‐Wollheim M. , Andersen O. , Svejgaard A. , Edland A. , Mellgren S.I. , Compston A. , Vartdal F. , Spurkland A.
Published: February 2004

Abstract: In order to analyze whether loci in the human leukocyte antigen (HLA) class I region may contribute to the HLA class II‐associated genetic susceptibility to multiple sclerosis (MS), we examined selected microsatellite markers in 177 Nordic sib‐pair families, 222 British sib‐pair families, 323 sporadic Norwegian MS patients and 386 Norwegian controls. All samples were, in addition, genotyped for the HLA‐DR DQ haplotype, and the Norwegian case‐control samples were also typed for HLA‐A and ‐B loci. In the Norwegian sporadic MS patients association was seen with HLA‐A, HLA‐B, and with the D6S265 marker, located 100 kb centromeric to HLA‐A. Associations with HLA‐A and D6S265 loci were also suggested when restricting the analysis to HLA‐DR15 haplotypes. In the sib‐pair data a similar trend was seen with marker D6S265. Higher genotypic relative risk (GRR) was found for individuals who carry both HLA‐DR15 and ‐A3 (GRR = 15), compared to those who carry only HLA‐DR15 (GRR = 7), only HLA‐A3 (GRR = 3) or none of these alleles (GRR = 1). The highest risk was conferred by a combination of HLA‐DR15 and ‐A3 (odds ratio (OR) = 5.2). These results suggest that HLA‐A or a gene in linkage disequilibrium with it may contribute to the HLA class II‐associated genetic susceptibility to MS.
The beneficial role of inhibitory KIR genes of HLA class I NK epitopes in haploidentically mismatched stem cell allografts may be masked by residual donor‐alloreactive T cells causing GVHD
Authors: Bishara A. , De Santis D. , Witt C.C. , Brautbar C. , Christiansen F.T. , Or R. , Nagler A. , Slavin S.
Published: February 2004

Abstract: HLA allele mismatches will provoke T‐cell alloreactivity after allogeneic stem cell transplantation. As donors and recipients are usually HLA matched, the public HLA epitopes that are recognized by natural killer (NK) cells (NK epitopes) are rarely mismatched, and therefore there is rarely potential for NK alloreactivity arising from the absence of ligands for inhibitory killer immunoglobulin‐like receptors (KIR). Transplants using related donors sharing only one haplotype (haploidentical donors) represent a setting in which NK epitopes are often mismatched, thus resulting in the potential for NK alloreactivity. We have analyzed engraftment, acute graft vs host disease (GVHD), leukemia relapse, and survival in 62 haploidentical transplants in relationship with potential NK alloreactivity, inhibitory, and activating KIR genes of class I HLA NK epitopes. Potential NK alloreactivity in the rejection direction was not associated with any outcome variable. Potential NK alloreactivity in the GVHD direction was associated with an increased incidence of severe GVHD and poorer patient survival but not with non‐engraftment nor leukemia relapse. A higher number of activating KIR receptors in the genome of the donor was associated with a higher prevalence of GVHD. These results suggest that lack of extensive T‐cell depletion in haploidentical transplantation is associated with high GVHD rates and diminishes the benefits of NK‐cell alloreactivity.
The efficacy low dose of prednisolone in the treatment of hyperemesis gravidarum
Authors: Ziaei Saeideh , Hosseiney Fatima Sadat , Faghihzadeh Soghrate
Published: February 2004

Background.  To determine whether low dosages of prednisolone are effective in the treatment of outpatients with hyperemesis gravidarum.

Methods.  Eighty pregnant women with gestational ages of 6 to 12 weeks and persistent nausea and vomiting participated. The women were assigned by simple randomization to receive prednisolone 5 mg daily or promethazine 75 mg daily by oral route for 10 days. The severity of nausea, frequency of vomiting per day, sickness and the drugs' side‐effects were compared (Fisher's exact test, Mann–Whitney U‐test, Odds Ratio test).

Results.  The women who received promethazine responded better in the first 48 h (p = 0.02). With continuation of the treatment, the difference decreased, and one week after completion of the treatment, the subjects who had received prednisolone had less symptoms.

Conclusion.  Promethazine reduces the symptoms of hyperemesis gravidarum faster than prednisolone, but during prolonged treatment, prednisolone has at least the same effects on the symptoms and less drug side‐effects.
Eclampsia at a tertiary hospital 1973–99
Authors: Rugarn Olof , Carling Moen Susanne , Berg Göran
Published: February 2004

Background.  To investigate changes in incidence, patient characteristics, comorbidity and in the care provided in cases of eclampsia at a tertiary hospital during the period 1973–99.

Methods.  Thirty‐nine cases were identified through the Swedish National Birth Registry. Incidences and rates regarding patient characteristics and outcomes (duration of intensive care unit surveillance, assisted ventilation, multiple seizures, predefined major complications, perinatal mortality, small for gestational age, and neonatal intensive care surveillance) were compared between the time periods 1973–79, 1980–89 and 1990–99 with trend analysis.

Results.  The incidences in the three time periods were 3.0/10 000 births [95% confidence interval (CI) 0.1–5.9], 6.2/10 000 births (95% CI 2.7–9.7) and 10.9/10 000 births (95% CI 6.4–15.4), respectively, which constitutes a significant difference according to trend analysis (p = 0.006). There were no differences in patient characteristics or comorbidity. Onset occurred in hospital in 85% of the cases.

Conclusions.  The increase in the incidence of eclampsia reported here is contrary to international trends up until the early 1990s. The incidence in 1990–99 is also higher than the reported national incidence in Sweden 1976–80, which was 2.9/10 000 births. Despite successful identification of women at risk for eclampsia and hospital surveillance, several cases were not prevented. Better prognostic tests that identify impending eclampsia are needed to bring the incidence down further.
Acupuncture relieves pelvic and low‐back pain in late pregnancy
Authors: Kvorning Nina , Holmberg Catharina , Grennert Lars , Åberg Anders , Åkeson Jonas
Published: February 2004

Background.  The study was designed to evaluate the analgesic effect and possible adverse effects of acupuncture for pelvic and low‐back pain during the last trimester of pregnancy.

Methods.  Following individual informed consent, 72 pregnant women reporting pelvic or low‐back pain were randomized during pregnancy weeks 24–37 to an acupuncture group (n = 37) or to a control group (n = 35) at three maternity wards in southern Sweden. Traditional acupuncture points and local tender points (TP) were chosen according to individual pain patterns and stimulated once or twice a week until delivery or complete recovery in acupuncture patients. Control patients were given no sham stimulation. Throughout the study period each patient made weekly visual analog scale (VAS) evaluations of maximal and minimal pain intensity as well as three‐point assessments of pain intensity during various activities.

Results.  During the study period, VAS scorings of pain intensity decreased over time in 60% of patients in the acupuncture group and in 14% of those in the control group (p < 0.01). At the end of the study period, 43% of the acupuncture patients were less bothered than initially by pain during activity compared with 9% of control patients (p < 0.01). No serious adverse effects of acupuncture were found in the patients, and there were no adverse effects at all in the infants.

Conclusion.  Acupuncture relieves low‐back and pelvic pain without serious adverse effects in late pregnancy.
Are sociodemographic and regional and sample factors associated with prevalence of abuse?
Authors: Swahnberg Katarina , Wijma Barbro , Schei Berit , Hilden Malene , Irminger Kirstine , Wingren Gun B.
Published: February 2004

Background. The aims of the present study were: 1) to estimate the prevalence of emotional, physical and sexual abuse and abuse in the health care system, and 2) to study the associations between prevalence of abuse and sociodemographic and sample variables.

Methods. This cross‐sectional study used a validated postal questionnaire in four Swedish samples; patients at three gynecologic clinics with different character and in different regions (n = 2439) and women in one randomized population sample (n = 1168).

Results. Any lifetime emotional abuse was reported by 16.8–21.4% of the women; physical abuse by 32.1–37.5%; sexual abuse by 15.9–17.0%; and abuse in the health care system by 14.0–19.7%. For 7–8% abuse had included life threats and 9–20% of all women in the study currently suffered from their experiences of abuse. Most women had not disclosed their background of abuse to the gynecologist.

There were differences in sociodemographic variables between the four samples. Generally, in the multivariate analyses we found associations between prevalence of abuse and age, educational level, civil status and occupation, but no consistent association between prevalence of abuse and sample variables.

Conclusion. Lifetime prevalence rates of the four kinds of abuse were high in all samples as measured by the NorVold Abuse Questionnaire (NorAQ), and 1/10–1/5 women in the study suffered currently from abusive experiences. In multivariate analyses prevalence of abuse was consistently associated with sociodemographic but not to sample variables.
Does pain relief during delivery decrease the risk of postnatal depression?
Authors: Hiltunen Pauliina , Raudaskoski Tytti , Ebeling Hanna , Moilanen Irma
Published: February 2004

Background.  To test the hypothesis that sufficient pain relief during delivery decreases the risk of postnatal depression.

Methods.  As part of a prospective follow‐up study of the risk factors for postnatal depression and its impact on the mother–infant interaction and child development, 185 parturients filled in the Edinburgh Postnatal Depression Scale (EPDS), first during the first postpartum week and again (n = 162) 4 months later. The incidence and the risk of high EPDS scores was calculated according to the mode of delivery and the mode of pain relief during vaginal delivery, also after adjusting for the length of labor.

Results.  Mothers who received epidural/paracervical blockade during their delivery spent less time in the delivery room than mothers in the nitrous oxide/acupuncture group (p = 0.033) or mothers with no pain relief (p = 0.026) and had shorter length of labor than mothers without pain relief (p = 0.04). The adjusted risk of depressive scores at the first postnatal week was decreased in the epidural/paracervical group when compared with no analgesia group (OR: 0.25, 95% CI: 0.09–0.72). This difference was not shown at 4 months postpartum. Elective or emergency cesarean section did not increase the risk of high EPDS scores at the first week or at 4 months postpartum.

Conclusion.  The mode of pain relief during vaginal delivery seems to be associated with the incidence of postpartum depression, especially immediately after delivery.
Danish obstetricians' personal preference and general attitude to elective cesarean section on maternal request: A nation‐wide postal survey
Authors: Bergholt Thomas , Østberg Birgitte , Legarth Jesper , Weber Tom
Published: February 2004

Objective.  To assess Danish obstetricians' and gynecologists' personal preference and general attitude towards elective cesarean section on maternal request in uncomplicated single cephalic pregnancies at term.

Design.  Nation‐wide anonymous postal questionnaire.

Population.  Four hundred and fifty‐five obstetricians and gynecologists identified in the records of the Danish Society of Obstetrics and Gynecology from January 2000.

Main outcome measures.  Personal preference on the mode of delivery and general attitude towards elective cesarean section on maternal request in an uncomplicated single cephalic pregnancies at term.

Results.  Of Danish specialists in obstetrics and gynecology, 1.1% would prefer an elective cesarean section in an uncomplicated pregnancy at 37 weeks of gestation with fetal weight estimation of 3.0 kg. This rose to 22.5% when the fetal weight estimation was 4.5 kg at 37 weeks. The main reasons given for preferring abdominal deliveries was the risk to the fetus, risks of perineal injury, and urinary and anal incontinence.

Of Danish specialists in obstetrics and gynecology, 37.6% agreed with a woman's right to have an elective cesarean section on maternal request without any medical indication. Obstetricians and gynecologists who had experienced a noninstrumental vaginal delivery themselves or practiced as a private gynecologist only, were less likely to agree with the woman's right to elective cesarean section on maternal request.

Conclusion.  The vast majority of Danish obstetricians and gynecologists would personally prefer vaginal delivery in uncomplicated pregnancies, but nearly 40% agree with the woman's right to request a cesarean section.
Dynamics of selected MHC class I and II molecule expression in the course of HPV positive CIN treatment with the use of human recombinant IFN‐γ
Authors: Sikorski Marek , Bobek Malgorzata , HenryK Zrubek  , Marcinkiewicz Janusz
Published: February 2004

Background.  Studies consistently reveal downregulation of major histocompatibility complex (MHC)‐I molecules or/and selective loss of individual MHC‐I alleles and upregulation of MHC‐II molecules in the areas of cervical intraepithelial neoplasia (CIN) and in cervical cancers. In vitro studies demonstrated the interferon‐gamma (IFN‐γ) potential of MHC class I and II molecule upregulation followed by increased cytolytic response against some cervical cancer cell lines.

Aim of the study.  In vivo assessment of the correlation between regression/persistence state of CIN and the IFN‐γ‐induced changes in both class of selected MHC molecule expression.

Methods.  Seventeen subjects with CIN I/CIN II associated with high‐risk HPV infection underwent uniform IFN‐γ treatment (four intracervical injections over 2‐day interval for a total dose of 6 000 000 IU). Immunohistochemical staining has been performed within cervical punch biopsy specimens with the use of monoclonal antibody reacting with HLA‐DR, HLA‐HC and HLA‐Bw4, and the mean proportion of given molecules expressing keratinocytes was counted before, immediately after and 2 months after IFN‐γ treatment

Results.  The analysis revealed a rapid and significant increase of the HLA‐Bw4 proportion in response to IFN‐γ, persistent in the group of complete responders (with CIN clearance). No significant changes in the proportion of HLA‐HC 10 positive cells in response to IFN‐γ administration was demonstrated, nor a significant increase in HLA‐DR positivity; however, the transient trend towards increasing the proportion of HLA‐DR immediately after treatment completion was observed.

Conclusions.  Upregulation of selected MHC class I allele expression, but not necessary MHC class II or heavy chain fragments of MHC‐I, induced by IFN‐γ correlates with the resolution of cervical intraepithelial lesions and high‐risk HPV DNA clearance in vivo.
Can antepartum computerized cardiotocography predict the evolution of intrapartum acid‐base status in normal fetuses?
Authors: Bellver José , Perales Alfredo , Maiques Vicente , Serra Vicente
Published: February 2004

Background.  To study the relationship between antepartum computerized cardiotocography (cCTG) and the evolution of intrapartum fetal acid‐base balance in a low‐risk population.

Methods.  Forty‐nine healthy fetuses were prospectively followed up by antepartum cCTG (Oxford System 8002), fetal scalp blood sampling at the onset of the active phase of dilatation (3 cm) and at the beginning of the second stage of labor (10 cm) and study of acid‐base status at birth in the umbilical cord. Correlation studies and linear regression analysis were performed.

Results.  Normal prelabor cCTG was followed by normal fetal acid‐base balance in the different study periods. No relationship was found between cCTG parameters and the absolute values of fetal acid‐base status. However, the more favorable the antepartum cCTG parameters were, the more favorable the fetal acid‐base evolution during the active phase of dilatation was. In contrast, no significant correlations were found between antepartum cCTG and fetal acid‐base changes during the second stage of labor.

Conclusions.  In normal fetuses, a single antepartum cCTG identified correctly fetal well‐being during labor and at birth and was able to predict fetal acid‐base evolution during the active phase of dilatation. However, fetal biochemical changes during the second stage could not be predicted by any antepartum cCTG parameter.
Prevalence of fungi in the vagina, rectum and oral cavity in pregnant diabetic women: relation to gestational age and symptoms
Authors: Nowakowska Dorota , Kurnatowska Alicja , Stray‐Pedersen Babill , Wilczynski Jan
Published: February 2004

Objectives.  To estimate the prevalence of fungi in the vagina, rectum and oral cavity in pregnant women with diabetes mellitus (DM) type I or gestational diabetes mellitus (GDM) and in healthy controls; to assess the influence of gestational age on the prevalence of fungi; to compare the vaginal symptoms within the groups; and to analyze the multifocality of fungal invasions.

Methods.  A total of 251 women were examined: 47 with DM, 72 with GDM and 132 controls. Samples were collected from the vagina, rectum and oral cavity of all women and cultured on Sabouraud media.

Results.  Fungi were found in 59.8% in at least one of the three locations in all women. Vaginal mycosis was diagnosed more often (p < 0.001) in pregnancies with DM [40.4%, odds ratio (OR) 4.3, confidence interval (CI) 2.41–4.85] than with GDM (22.2%, OR 1.84, CI 0.99–2.12) and nondiabetics (13.6%, OR 1.0). The risk of trifocal mycosis was higher in DM women (OR 2.7, CI 1.72–4.45), than in the controls. Only in 27.6% of symptomatic women were fungi detected in vagina. However, 60.4% of women with vaginal mycosis had symptoms. Among women without mycosis, 42.4% were symptomatic, and discharge was more common in the DM group (50%) than in the GDM group (21.4%) and the controls (28.1%; p < 0.002). The prevalence of fungi in the groups was not influenced by gestational age.

Conclusions.  The risk of vaginal mycoses in DM women is more that four times higher and in pregnancies with GDM nearly two times higher than in controls. The risk of trifocal mycosis in DM women is nearly three times higher than in nondiabetics. There is a poor correlation between symptoms of vaginitis and fungal infection. We did not confirm the influence of the gestational age on the prevalence of fungi.
The techniques of trocar insertion and intraoperative urethrocystoscopy in tension‐free vaginal taping: an experience of 600 cases
Authors: Wang Alex C.
Published: February 2004

Background.  To determine the frequency of lower urinary tract (LUT) injury for stress incontinent women undergoing the tension‐free vaginal tape (TVT) procedure with or without concomitant procedures.

Methods.  Over a period of 5 years, 600 women who had stress urinary incontinence (SUI), with or without pelvic prolapse, consecutively underwent the TVT procedure either with or without concomitant surgery. All study subjects underwent intraoperative transurethral urethrocystoscopy. During the examination 34 (6%) women at high risk of ureteral injury also received intravenous injection of 6 mL of diluted methylene blue to observe the patency and function of the ureter as well as the integrity of the bladder.

Results.  The mean patient age was 52.75 years (range 32–76) and mean parity was 2.54 (range 0–6). Of the 600 women, 188 (31.4%) had had previous surgery, 169 (28.2%) had concomitant surgery, and 9 (1.5%) had abnormal urethrocystoscopic findings. These findings included one case each of previously placed suspension sutures, granuloma‐like tissue in the bladder, a delayed dye emission from the ureteric orifice, an adhesive band in the urethra, three cases of perforation of the bladder by the trocar and two cases of an area of thin bladder mucosa. The bladder perforation rate related to the TVT device was 0.8% (5/600).

Conclusions.  Based on the data of this 5‐year review, and a high rate of bladder injury (0–25%) reported in the literature, intraoperative urethrocystoscopy is imperative in the TVT procedure, although the rate of bladder injury was only 0.8% in the present study.
Endometrial thickness as an orienting factor for the medical treatment of unruptured tubal pregnancy
Authors: Da Costa Soares Roberto , Elito Júlio , Han Kyung Koo , Camano Luiz
Published: February 2004

Objectives.  To evaluate the efficacy of the endometrial thickness measurement through transvaginal ultrasound as an orienting factor for the medical treatment of unruptured tubal pregnancy with a single dose of methotrexate in order to select the best cases for the medical treatment.

Methods.  A prospective study, in which the largest measurement of endometrial thickness in millimeters was evaluated, along the longitudinal uterine axis, by means of transvaginal ultrasound. A total of 38 patients meeting the inclusion criteria for single‐dose methotrexate treatment [50 mg/m2 intramuscularly (i.m.)] were included in the study. We observed whether there was any difference in mean value of endometrial thickness and initial beta‐human choriongonadotropin levels, between the cases that evolved successfully with the treatment, and those that failed.

Results.  The mean value of endometrial thickness and initial beta‐human choriongonadotropin (β‐hCG) levels, for patients evolving successfully with medical treatment (28 cases), were 6.39 mm and 1936.2 mUI/ml, respectively, while the mean values for failures were 11.70 mm and 6831.3 mUI/ml. We carried out statistical analysis using the ‘Student's t‐test', with p < 0.05.

Conclusions.  The mean value of endometrial thickness, along the longitudinal uterine axis through transvaginal ultrasound, reflects hormonal action and has been demonstrated to be another important parameter in indicating the medical treatment of an unruptured tubal pregnancy.
Labor analgesia for the parturient with cardiac disease: what does an obstetrician need to know?
Authors: Kuczkowski Krzysztof M.
Published: February 2004

Maternal heart disease complicates 0.2–3% of pregnancies. The optimal management of the pregnant patient with cardiac disease depends on the cooperative efforts of the obstetrician, the cardiologist and the anesthesiologist involved in peripartum care. A comprehensive understanding of physiology of pregnancy and pathophysiology of underlying cardiac disease is of primary importance in provision of obstetric analgesia or anesthesia for this high‐risk group of patients. This article will review the current guidelines and standards pertinent to management of obstetric analgesia and anesthesia in parturients with cardiac disease.
Is Official Exchange Rate Intervention Effective?
Authors: Taylor Mark P.
Published: February 2004

I examine the effectiveness of exchange rate intervention within the context of a Markov‐switching model for the real exchange rate. The probability of switching between stable and unstable regimes depends nonlinearly upon the amount of intervention, the degree of misalignment and the duration of the regime. Applying this to dollar–mark data for the period 1985–98, I find that intervention increases the probability of stability when the rate is misaligned, and that its influence grows with the degree of misalignment. However, intervention within a small neighbourhood of equilibrium will result in a greater probability of instability.
Modelling Probabilities of Devaluations
Authors: Mundaca Gabriela
Published: February 2004

I show why, when the realized rates of depreciation within the exchange rate band are regressed on a given information set and conditioned on (ex post) actual no realignment (à la drift adjustment), a ‘peso problem’ is still encountered. The reason is that the frequency of realignments in the data need not be the same as the frequency of the (even small) subjective probabilities that a realignment may take place. I suggest an alternative approach to solve the peso problem and provide consistent estimates. My estimates of the expected realignment rates are greater than the ones obtained using the drift adjustment method.
Austria's Demand for International Reserves and Monetary Disequilibrium: The Case of a Small Open Economy with a Fixed Exchange Rate Regime
Authors: Badinger Harald
Published: February 2004

Using a vector error correction approach, I estimate Austria's demand for international reserves over the period 1985:1–1997:4 and test for short‐run effects of the disequilibrium on the national monetary market. I find that Austria's long‐run reserve demand can be described as a stable function of imports, uncertainty and the opportunity cost of holding reserves with strong economies of scale. The speed of adjustment takes a value of 38 per cent. The results confirm that an excess of money demand (supply) induces an inflow (outflow) of international reserves as postulated by the monetary approach to the balance of payments.
Education Choice, Endogenous Growth and Income Distribution
Authors: Cardak Buly A.
Published: February 2004

This paper studies an economy where parents can choose between public or private schools and can vote on taxes used to fund public schools. The model is calibrated to US data and studied using simulations. A bimodal income distribution emerges where public education students converge to a low‐income equilibrium while private education students experience endogenous growth with higher incomes. However, public education students experience long‐run growth through a spillover from private education students. Possible problems with the existence of a private alternative to pubic education, such as the emergence of a education‐based class structure, are identified.
Duration‐Dependent Unemployment Insurance Payments and Equilibrium Unemployment
Authors: Coles Melvyn , Masters Adrian
Published: February 2004

This paper develops a model of equilibrium unemployment with duration‐dependent unemployment insurance (UI) payments. As the government does not observe job offers, there is a moral hazard problem because the option of receiving further UI payments raises the job‐seeker's value of remaining unemployment. Extending the duration of UI payments while reducing the level of payments, to hold total generosity constant, results in higher negotiated wages. Simulations suggest that a generosity neutral switch from a six‐month UI scheme to a one‐year scheme has small effects, but a switch to an indefinite scheme has a large impact on wages and unemployment.
Interest Rate Pass‐Through and Monetary Transmission: Evidence from Individual Financial Institutions' Retail Rates
Authors: Hofmann Boris , Mizen Paul
Published: February 2004

Official interest rate changes should influence short rates on money market instruments and retail products, such as deposit accounts and mortgages, but complete pass‐through is often taken for granted. This paper provides a theoretical and econometric framework for assessing the evidence for this assumption using seventeen years of monthly data for rates on thirteen deposit and mortgage products offered by individual UK financial institutions. The methodology allows for asymmetries and non‐linearities in adjustment and the results show that the speed of adjustment in retail rates depends on whether the perceived ‘gap’ between retail and base rates is widening or narrowing.
Efficiency of Rational Learning with Private Information
Authors: Heinemann Maik
Published: February 2004

The paper examines the welfare properties of rational learning by privately informed risk‐neutral firms. It is shown that the market solution is inefficient, with firms putting too much weight on their private information and public information therefore accumulating suboptimally slowly. It might even be the case that more private information is harmful to welfare — a result that it is impossible if private information is used efficiently. Moreover, it is shown that distortionary taxation of the firms' revenues might help to overcome the underlying information externality problem. All in all, therefore, the results qualify other results obtained in the literature.
Firm's Output under Uncertainty and Asymmetric Taxation
Authors: Zilcha Itzhak , Eldor Rafael
Published: February 2004

We consider competitive firms operating under price uncertainty when taxation is asymmetric (i.e. profits are taxed at a higher rate than losses are compensated). In the absence of risk sharing tools, the larger ‘gap’ in taxation may either lower or increase the firm's optimal output, depending on whether the relative measure of risk aversion is less than or larger than 1. In the presence of risk sharing markets optimal output does not depend on the tax rates, nor on the price distribution or the firm's attitude towards risk. The firm will engage in hedging and, as a result, will lower its expected taxes.
Bribes in a Supply Line
Authors: Sanyal Amal
Published: February 2004

The paper models the practice of charging bribes for faster delivery of essential services. It then examines the possibility of curbing corruption by supervision and by introducing competition among delivery agents. It is argued that a supervisory solution eludes the problem because no hard evidence of the reduction of corruption can be established for this type of offence. It is then shown that using more than one supplier reduces the bribe rate and the waiting period for both bribe‐payers and others; and the aggregate gain of consumers exceeds the cost of hiring additional suppliers.
Adaptive plasticity in nest‐site selection in response to changing predation risk
Authors: Forstmeier Wolfgang , Weiss Ingo
Published: February 2004

Birds selecting a nest site have to find the best compromise between the risk of encountering predation, the availability of food near to the nest and microclimatic requirements. As the optimal solution of this problem will vary with changes in predator abundance, we ask whether birds are capable of assessing such changes and of adjusting their nest‐site choice accordingly. The reproductive success of dusky warblers Phylloscopus fuscatus, breeding in a mosaic of bushland and tundra habitat in the Russian Far East, varied greatly depending on the abundance of a nest predator, the Siberian chipmunk Tamias sibiricus. Using artificial nests we analysed which strategies dusky warblers should follow to avoid nest predation by chipmunks. We then compared the nest sites which dusky warblers actually had chosen in years with very high chipmunk densities (1998 and 1999) with those chosen in 1997, when chipmunks were almost absent from the study area. We found that safe nest‐sites were preferred over those offering other advantages (microclimate, proximity to food) when the risk of predation was high, and we could not detect any confounding factor that might alternatively have caused these striking between‐year differences. Our study suggests that even a short‐lived passerine may be capable of choosing its nest site according to the actual predation risk. We show that such behavioural plasticity can lead to a paradoxical situation where better‐protected nest‐sites (selected in years and areas with high risk), on average, suffer greater predation than sites offering low safety. Thus, behavioural plasticity, if undetected, may result in serious misinterpretation of nest‐predation patterns. A review of the literature suggests that adaptive plasticity in nest placement may be more widespread than is currently recognized.
Biodiversity effects on ecosystem functioning: insights from aquatic systems
Authors: O. Gessner Mark , Inchausti Pablo , Persson Lennart , G. Raffaelli David , S. Giller Paul
Published: February 2004

Unprecedented rates of species extinctions have prompted extensive research into the consequences of biodiversity losses on ecosystem functioning. While aquatic species are most threatened, research with freshwater and marine model systems has lagged behind progress made in terrestrial environments. This editorial to a special feature summarizes the main outcomes of a conference aimed at setting the stage for exploring the potential of aquatic systems to assess the role of biodiversity in ecosystem functioning. This series of papers proposes fresh approaches to the study of biodiversity effects on ecosystem functioning, outlines a new way of analyzing experimental data, presents a model that considers scale as an important factor determining outcomes, explores the effects of multiple stressors on species richness and ecosystem processes, and develops a food‐web perspective that relates ecosystem properties to biodiversity. An insightful synthesis of lessons learned from aquatic systems is premature at present, but the papers clearly demonstrate the role that marine and freshwater systems can play in resolving open questions. The implications go well beyond the biodiversity in, and functioning of, ecosystems shaped by free‐flowing or standing water.
Non‐lethal effects of predators on prey growth rates depend on prey density and nutrient additions
Authors: Turner Andrew M.
Published: February 2004

A number of studies show that predators can depress prey growth rates by inducing reductions in foraging activity, but the size of this non‐lethal effect is quite variable. Here I investigate how prey density and resource productivity may alter the extent to which predators depress the growth rates of their prey. Theory predicts that when resources are overgrazed, an increase in predation risk will have little net effect on individual food intake because the decline in foraging effort will be offset by an increase in resource level. Thus, the non‐lethal effects of predators on prey growth rates should depend upon prey density and resource productivity in a predictable manner, with the growth penalty imposed by predators being strongest when resources are undergrazed and weakest when resources are overgrazed. I tested this hypothesis by manipulating predation risk, prey density, and nutrient additions in a mesocosm experiment with the pulmonate snail Helisoma trivolvis. Refuge use by snails was 45% higher in the presence of caged crayfish than in their absence. Snail growth rates were reduced, on average, by 24% in the presence of caged crayfish. However, the magnitude of the growth penalty exacted by crayfish depended on snail density and nutrient additions. When snails were stocked at high density and nutrient additions were low, growth suppression was just 2.6%. At the other extreme, when snails were at low density and nutrient additions were high, growth suppression was 44.6%. Thus, the non‐lethal effects of predators on prey growth depend on environmental context, illustrating an important link between individual traits and system‐level properties.
Does functional redundancy exist?
Authors: Loreau Michel
Published: February 2004

Functional redundancy has often been assumed as an intuitive null hypothesis in biodiversity experiments, but theory based on the classical Lotka‐Volterra competition model shows that functional redundancy sensu stricto is incompatible with stable coexistence. Stable coexistence requires differences between species which lead to functional complementarity and differences between the yields of mixtures and monocultures. Only a weaker version of functional redundancy, i.e. that mixture yields lie within the range of variation of monoculture yields, is compatible with stable coexistence in Lotka‐Volterra systems. Spatial and temporal environmental variability may provide room for functional redundancy at small spatial and temporal scales, but is not expected to do so at the larger scales at which environmental variations help maintain coexistence. Neutral coexistence of equivalent competitors, non‐linear per capita growth rates, and lack of correlation between functional impact and biomass may provide the basis for the existence of functional redundancy in natural ecosystems. Overall, there is a striking parallel between the conditions that allow stable coexistence and those that allow overyielding.
Density‐dependent reproduction in the European rabbit: a consequence of individual response and age‐dependent reproductive performance
Authors: G. Rödel Heiko , Bora Agnes , Kaiser Jürgen , Kaetzke Paul , Khaschei Martin , Von Holst Dietrich
Published: February 2004

Density dependence of reproduction has generally been proposed to be caused by habitat heterogeneity and by the individual response of reproductive output. However, a further mechanism might generate density dependence of average reproductive rates. High density situations might be associated with a high proportion of first‐season breeders which often show a principally lower reproductive performance. We tested for the existence of the latter mechanism as well as for density‐dependent individual changes of reproductive effort in a population of European rabbits living in a homogeneous grassland habitat. The study was conducted over a period of eleven years. Overall, a strong relationship between mean reproductive rates and the breeding density of females was apparent. All necessary conditions for the presence of a density‐dependent effect caused by age‐dependent reproduction were fulfilled: Fluctuations of breeding density were paralleled by variations in the proportion of one‐year‐old females. These one‐year‐old, first‐season breeders showed a consistently lower reproductive performance than older females, which might be caused by their lower body mass and their lower social rank. However, we also found strong evidence for density‐dependent response of individual reproductive effort: Individual changes in fecundity over successive years were explained by changes in the breeding density of females. The results suggest that density dependence of reproduction in European rabbits is due to an interaction of age‐dependent reproductive performance together with short‐term fluctuations in breeding density, and a density‐dependent, individual based response of reproductive rates. We further conclude that the lower reproductive performance of first‐season breeders in age‐structured animal populations may contribute substantially to interannual, and under particular circumstances to density‐dependent variations of mean reproductive rates.
Masting and trophic cascades: interplay between rowan trees, apple fruit moth, and their parasitoid in southern Norway
Authors: Satake Akiko , N. Bjørnstad Ottar , Kobro Sverre
Published: February 2004

We analyzed berry production in rowan, Sorbus aucuparia L., in southern Norway and examined the ramifying effects of rowan masting on the dynamics of the dominant seed predator and its parasitoid. The apple fruit moth, Argyresthia conjugella Zeller, is a pre‐dispersal seed predator of rowan. The larva of the apple fruit moth rely on rowan berries, which in turn is attacked by the parasitoid wasp, Microgaster politus Marsh. We found classic masting in rowan: berry production varied across years (the mean coefficient of variation=1.02) and was spatially synchronized at large scale (the averaged correlation coefficient=0.67). Berry production represented a two‐year cycle in western but a three‐year cycle in eastern Norway. The abundance of the moth and the parasitoid also varied across years and were spatially synchronized. The degree of spatial synchrony decreased and cyclicity became obscure with increasing trophic level. We attempted to assess two different components to the predator satiation, functional and numerical satiations, based on a simple population dynamics model. The observed pattern of seed predation testified that both of functional and numerical satiations were at work in this system. In a comparison at different locations, rowan trees with more variable berry production were more effective in reducing losses to the seed predator. The parasitoids also seemed to experience satiation through the fluctuation in their host abundance. These results show that rowan masting has an adaptive foundation, which impacts the dynamics of higher trophic levels.
Plant structural defences against browsing birds: a legacy of New Zealand's extinct moas
Authors: Bond William J. , Lee William G. , Craine Joseph M.
Published: February 2004

Browsing by large vertebrates has been a major force in the evolution of terrestrial plants but Holocene extinctions of the browsers have left a legacy of broken biotic partnerships. Ratite birds were the largest herbivores in several regions, such as the moas of New Zealand. Many woody plants there have a distinct form of branching, described as “divaricate”, with thin, wide angled, branches intertwining to form a tangled canopy. Divaricate branching has been interpreted as a form of protection against climate extremes or as an anachronistic defense against the extinct moas. Here we report the first experimental evidence that many of these plants are defended against extant ratite browsers. In feeding experiments on two tree species with different (heteroblastic) juvenile and adult branch morphology, emus and ostriches obtained adequate feeding rates from adult shoots but sub‐maintenance feeding rates from juvenile shoots with the ratite‐resistant traits. Divaricate juvenile shoots suffered 30–70% less biomass removal to the birds than adult shoots. Ratites browse by a distinctive clamping and tugging action. Structural defence traits that exploit the limitations of this feeding mode include narrow, strong, elastic branches that resist being torn off, wide branching angle (“divaricate”) that makes shoots difficult to swallow, and small, widely spaced leaves. This novel plant architectural defence has developed in at least 20% of the native woody flora of New Zealand, including 10 heteroblastic tree species that exhibit the ratite‐resistant strategy until they reach ca 3 metres height. It is also a major axis of variation amongst homoblastic woody shrub species. The defences are useless against mammalian browsers that shear shoots, contributing to marked decreases in the abundances of ratite‐resistant species in New Zealand after the introduction of mammals.
On misinterpretations of pseudoreplication and related matters: a reply to Oksanen
Authors: Hurlbert Stuart H.
Published: February 2004

Pseudoreplication has become a widely accepted label for a certain class of statistical error common in the literature of ecology as well as of other fields. A wide‐ranging critique by L. Oksanen recently published in this journal criticizes the term and concept and concludes it to be a “pseudoissue,” one reflecting an intellectual disease, “a totally outdated epistemology” known as “inductionism.” The present article addresses some of Oksanen's complaints. His critique is based on a misconception of pseudoreplication, reflects unawareness of most of the literature on the topic, and mistakenly argues that the seriousness of the error is a function of whether an experiment is conducted in an inductive or deductive spirit. Oksanen's advocacy of using resources available for large scale ecology more for large numbers of experiments with unreplicated treatments than for fewer experiments with modest replication of treatments is unrealistic. It is based on an overly optimistic view of the ability of a meta‐analysis to compensate for deficiencies, such as very noisy estimates of treatment effects, of the individual studies that are fed into it. A definition is offered of the term manipulative experiment, since adequate ones are lacking in the literature. Attention is called to the fact that for certain types of manipulative experiments lacking treatment replication, there are valid ways to test for treatment effects.
Brown bears selectively kill salmon with higher energy content but only in habitats that facilitate choice
Authors: Gende Scott M. , Quinn Thomas P. , Hilborn Ray , Hendry Andrew P. , Dickerson Bobette
Published: February 2004

Pacific salmon return to spawn in thousands of streams across the Pacific Rim, from large rivers to tiny headwater streams. Once on the spawning grounds, salmon undergo dramatic biochemical changes as they metabolize stored lipid and protein reserves; at stream entrance, they will contain up to 85% more lipid and 40% more protein than at their senescent death a week or two later. Foraging brown and black bears that congregate at spawning streams thus encounter salmon that vary dramatically in their energy content and thus energetic reward. We hypothesized that bears would selectively kill salmon that are highest in energy content (fewest number of days on the spawning grounds) when they pursue salmon at small shallow streams where little effort is necessary to capture salmon, i.e. habitats that facilitate choice. In contrast, bears in environments where foraging is difficult (deeper, more complex streams) should be less selective and should capture salmon that are most available. We tested these ideas by examining predation rates on fish of different in‐stream ages (i.e. energy content) at three different streams that varied in physical habitat attributes. At a very shallow, simple stream, bears preferentially killed salmon that had spent the fewest days in the stream. At two streams where deeper water and woody debris provided refuges for salmon, predation rates increased with in‐stream age. At the shallowest streams encounter rates and capture success are likely equal among the high‐ and low‐energy salmon and thus predation rates reflect active choice by bears. In contrast capture success probably increases on the older salmon at the larger streams (due to a loss of vigor), and thus ‘preference’ for these fish increases due to decreasing effort necessary to capture them.