bluuebunny/crossref_metadata_2025 huggingface dataset:
Possible Identification of Cervicogenic Headache Among Patients With Migraine: An Analysis of 374 Headaches
Authors: Leone Massimo , D'Amico Domenico , Moschiano Franca , Farinotti Mariangela , Filippini Graziella , Bussone Gennaro
Published: May 2005

According to Sjaastad, the pain in cervicogenic headache, a form not recognized by the IHS, is long lasting and always side‐locked unilateral. The frequency of side‐locked unilateral pain (defined here as no change in side from onset) and other characteristics of cervicogenic headache were investigated in 300 outpatients using information collected on standard forms in structured interviews. Three hundred seventy‐four headaches diagnosed according to IHS criteria were identified. Three hundred forty‐eight of these headaches were long‐lasting (duration of more than 4 hours); migraine (65%) followed by tension‐type headache (25%) were the commonest forms. Side‐locked unilaterality was present in 29% (101 of 348), and occurred most frequently in migrainous disorders not fulfilling the criteria (25 of 56, 44.6%). This group differed significantly from the other migraine conditions for longer pain duration (P<0.02) and less frequent nausea, vomiting, photophobia, phonophobia (P<0.0001), and aggravation by physical activity (P<0.02). With these characteristics, this group resembled cervicogenic headache. However, in none of these patients was pain triggered by head or neck movements, and the frequency of head or neck trauma did not differ from other headaches. A more precise definition of clinical criteria for cervicogenic headache vs migraine is, therefore, required.
Cluster Headache: Cardiovascular Responses to Head‐up Tilt
Authors: Kruszewski Piotr , Bordini Carlos , Brubakk Alf O. , Sjaastad Otter
Published: May 2005

Head‐up tilt tests were performed in six cluster headache patients in a bout of attacks, but in a pain‐free interval at the time of investigation; and in eleven controls matched for age, basal blood pressure, and heart rate. A Doppler servomethod was used for a noninvasive, beat‐to‐beat blood pressure determination. There were no significant differences between the cluster headache and control groups for heart rate and systolic blood pressure response to the head‐up tilt. However, the average diastolic blood pressure seemed to drop more after the tilt in the cluster headache group than in the control group; in particular, in the later part of the test. This might suggest a dysfunction of the baroreflex in cluster headache patients in a bout, also outside of attacks, and most probably of the sympathetically‐mediated vasomotor response.
Acupuncture in Migraine: Long‐term Outcome and Predicting Factors
Authors: Baischer Wolfgang
Published: May 2005

Twenty‐six patients (19 women, 7 men), who suffered from chronic migraine according to IHS criteria, underwent acupuncture. In order to evaluate the long‐term stability of treatment effects, patients documented frequency, duration, and intensity of attacks as well as analgesic intake in a migraine diary, which was kept for 5‐week periods before treatment, immediately after treatment, and 3 years later. Data showed improvement greater than 33% for 18 patients (69%) at posttreatment and 15 patients (58%) at 3‐year follow‐up. Drug intake was reduced to 50% and did not re‐increase until follow‐up. Treatment outcome was associated with personality traits, but not depending on demographic data or severity of migraine.
Practice and Economics Cost Considerations in Headache Treatment Part 1: Prophylactic Migraine Treatment
Authors: Adelman James U. , Seggern Randal Von
Published: May 2005

Effective migraine treatment is clearly the most cost‐effective in terms of both direct and indirect costs. Patient education, behavior changes, and prudent medication selection can minimize costs. Low‐dose aspirin may reduce headache frequency. Among the antidepressant medications used, amitriptyine 25 mg, 3 qhs ($4.16/month) and doxepin 25 mg, 3 qhs ($10.50/month) remain the standard. Imipramine (25 mg, 3 qhs ($3.75/month) is very inexpensive and should replace nortriptyline 25 mg, 3 qhs ($64.29/month) as a second‐line agent. The specific serotonin reuptake inhibitors are expensive and have no proven effect for migraine prevention.

Propranolol 80 mg bid ($7.80/month) is inexpensive and frequently a good choice among beta‐blockers. Atenolol 100 mg qd ($27.50/month) is less expensive than long‐acting propranolol 160 mg ($35.56/month) and nadolol 120 mg qd ($43.68/month) with equivalent effectiveness. It is thus recommended as the ong‐acting beta‐blocker of choice. Sustained‐release preparations of verapamil 240 mg qd ($31.98/ month) are twice the cost and less well‐absorbed than the standard preparation of 120 mg bid ($17.62/month).

Better information is needed concerning effectiveness and optimal dosing of some older low‐cost medications in the preventive treatment of migraine.
Clusterlike Headache. A Case of Sphenoidal Aspergilloma
Authors: Zanchin G. , Rossi P. , Licandro A.M. , Fortunato M. , Maggioni F.
Published: May 2005

Clusterlike headaches secondary to structural disease have been described. Nevertheless, most of the reports antedate the International Headache Society classification and, indeed, only a few appear to fit its criteria for a diagnosis of cluster headache. We report here a case of sphenoidal sinus aspergilIoma that fully complies with the criteria for cluster headache. This kind of lesion has never been described previously as a cause of a clusterlike headache.
Sumatriptan Prophylaxis for Postelectroconvulsive Therapy Headaches
Authors: DeBattista Charles , Mueller Kurt
Published: May 2005

Very little has been written about headaches following electroconvulsive therapy (ECT) but the incidence has been estimated at 26%. 1 Patients with a history of migraine occasionally have similar headaches precipitated by ECT.2 In addition, some patients may have headaches that persist for months after a series of ECT treatments, while some patients who have a preexisting headache problem report improvement with ECT.3

Serotonergic mechanisms have been proposed both for the efficacy of ECT and its tendency to produce headaches in susceptible patients.3,4 There have been no studies on the prophylaxis or treatment of post‐ECT headache. While various strategies have been suggested for these headaches, even case reports documenting the efficacy of these strategies are lacking. We, therefore, report a case of severe, refractory, post‐ECT headaches which responded to prophylactic treatment with sumatriptan.
Genetic Influence in Headaches: A Swedish Twin Study
Authors: Larsson Bo , Bille Bo , Pedersen Nancy L.
Published: May 2005

The heritability of liability to self‐reported migraine and nonmigrainous headaches was examined in two large cohorts from the Swedish Twin Registry consisting of 6448 (the older cohort) and 12 884 (the younger cohort) like‐sexed twin pairs. Higher concordance rates were consistently found for lifetime migraine among the monozygotic twins than in the dizygotic twins, as well as for migraine headaches of the recurrent disabling type. In addition, a higher concordance rate was found among the monozygotic twins than in dizygotic twins in a "mixed" group of possible tension‐type or mild migraine headaches (or both). The results of structural equation model‐fitting analyses showed that genetic effects for migraine headaches were stronger for the females (estimates ranging from 49% to 58%) than for the males (39% to 44%) in the two cohorts. Unique nonshared environmental effects were greatest for the “mixed” group in both sexes (estimates ranging from 60% to 69%). The results are discussed in view of similar large‐scale twin studies examining the heritability of liability to migraine.
Headache Associated With Aseptic Meningitis
Authors: Lamonte Marian , Silberstein Stephen D. , Marcelis John F.
Published: May 2005

A retrospective analysis of all patients admitted with the diagnostic codes of aseptic or viral meningitis was performed at two institutions over 3 years. Forty‐one patients with cerebrospinal fluid confirmation of aseptic meningitis (increased protein; increased white count; negative gram stain; and negative fungal, tuberculosis, and bacterial cultures) were analyzed.

All the patients had headache, which was typically severe and bilateral in 39 of the 41 patients. The headache was of abrupt onset or the worst of the patient's life in 24 of the patients. The quality of the headache, when described, was usually throbbing (11 of 14). Nineteen patients had prodromal symptoms, including malaise, myalgia, gastrointestinal symptoms, and urinary tract infections. All had associated symptoms, including nausea (25), vomiting (23), photophobia (18), stiff neck (25), and back pain (11). Thirty patients were febrile. Lumbar puncture was performed for headacheand fever unexplained by systemic illness in 30 patients, meningeal signs in 15, headache of abrupt onset or the worst headache ever in 24, neurologic signs or symptoms in 12, and for other reasons in 2. Computerized tomography, when performed, was negative in all cases. Focal neurologic findings were present in 5 patients, a decreased level of consciousness in 6, and papilledema in 1.

A severe headache that worsens, is abrupt in onset, or is the worst of the patient's life could be due to aseptic meningitis, bacterial meningitis, or a subarachnoid hemorrhage. Although not universally present, meningeal signs, fever, and neurologic signs or symptoms should alert one to a possible central nervous system infection.
A Piroxicam Derivative Partly Effective in Chronic Paroxysmal Hemicrania and Hemicrania Continua
Authors: Sjaastad Ottar , Antonaci Fabio
Published: May 2005

Piroxicam beta‐cyclodextrin has recently been observed to be equal to, or even possibly to be superior to, indomethacin (mainly with regard to side effects) in a single case of hemicrania continua. Piroxicam beta‐cyclodextrin, 20 to 40 mg per day, was, accordingly, tried in six patients with chronic paroxysmal hemicrania and six patients with hemicrania continua with a previously proven response to indomethacin. The study was conducted over a period of 3 weeks and in an open fashion. A placebo effect is considered to be negligible in these disorders. In such a comparison, piroxicam beta‐cyclodextrin seemed inferior to indomethacin, in particular in chronic paroxysmal hemicrania.
Spontaneous Intracranial Hypotension: Headache With a Reversible Arnold‐Chiari Malformation
Authors: Kasner S.E. , Rosenfeld J. , Farber R.E.
Published: May 2005

Spontaneous intracranial hypotension is characterized by severe postural headache in the setting of low CSF pressure, usually attributed to a cryptic CSF leak. We report a patient whose prolonged refractory headache was characterized by the clinical symptoms of occipital neuralgia, but was also associated with the radiographic appearance of an Arnold‐Chiari malformation, type I and low CSF pressure. After extensive diagnostic evaluation, CT cisternomyelography ultimately demonstrated a CSF leak at the C2 vertebral level. Symptomatic relief was sustained only with long‐term theophylline administration. The apparent Arnold‐Chiari malformation resolved with treatment of the low CSF pressure.
Oculocephalic Sympathetic Dysfunction in Posttraumatic Headaches
Authors: Khurana Ramesh K.
Published: May 2005

Oculocephalic sympathetic functions were assessed in five patients with posttraumatic headaches using the thermoregulatory sweat test and biochemical pupillary responses. Four patients demonstrated bilateral sympathetic dysfunction following whiplash injury, and one patient demonstrated unilateral sympathetic dysfunction following forehead injury. Bio‐chemical pupillary responses were diagnostic in the early posttraumatic period, while the thermoregulatory sweat test was abnormal up to 56 months following the injury. This study documents serious injury to the cervical sympathetic nerves in patients with posttraumatic headaches following whiplash injury, and shows the reliability of the thermoregulatory sweat test in identifying patients with long‐term oculocephalic sympathetic dysfunction. It also shows dissociated postganglionic cranial sympathetic dysfunction. Our experience and a review of the pertinent literature shows no convincing clinical or experimental evidence to establish oculocephalic sympathetic dysfunction as a direct cause of head pain, but it may exert an effect on cephalic pain through the trigeminovascular system.
Dihydroergotamine and Metoclopramide in the Treatment of Organic Headache
Authors: Gross D.W. , Donat J.R. , Boyle C.A.J.
Published: May 2005

Dihydroergotamine and metoclopramide have been used in the treatment of benign headache for many years. The presumed mechanism of action of dihydroergotamine and metoclopramide is related to these drugs' affinity for serotonergic receptors. We present three cases of the use of dihydroergotamine and metoclopramide in patients with organic headache (two patients with viral meningitis and one patient with meningeal carcinomatosis). All three patients had excellent symptomatic relief. Our results demonstrate that dihydroergotamine and metoclopramide can be effective in treating organic headache and, therefore, symptomatic relief can not be assumed to signify benign disease.
Patterns of Disagreement in Democratic Politics: Comparing Germany, Japan, and the United States
Authors: Huckfeldt Robert , Ikeda Ken'ichi , Pappi Franz Urban
Published: May 2005

An important ingredient in democratic politics is the experience of disagreement through social communication and political discussion. If people fail to encounter contrary viewpoints, their own views are never challenged, they are never forced to reconsider initially held opinions, and they are effectively excluded from democratic deliberation. This article examines patterns of political agreement and disagreement within the communication networks of citizens in Germany, Japan, and the United States. Several questions are addressed. Are there cross‐national differences in patterns of agreement and disagreement among citizens? To what extent are these patterns subject to individual attitudes, to the structure of communication networks, and to levels of aggregate support for particular preferences and opinions? Finally, what are the implications of disagreement for civic capacity and political engagement? Empirical analyses are based on cooperative election surveys conducted in each country during the early 1990s.
The Quality of Terror
Authors: De Mesquita Ethan Bueno
Published: May 2005

I present a model of the interaction between a government, a terrorist organization, and potential terrorist volunteers in which, as a result of an endogenous choice, individuals with low ability or little education are most likely to volunteer to join the terrorist organization. However, the terrorist organization screens the volunteers for quality. Consequently, the model is consistent with two seemingly contradictory empirical findings. Actual terrorist operatives are not poor or lacking in education. And yet lack of economic opportunity and recessionary economies are positively correlated with terrorism. The model also endogenizes the effect of government counterterrorism on mobilization. Government crackdowns have competing effects on mobilization: they decrease the ability of terrorists to carry out effective attacks (making mobilization less attractive), and they foment ideological opposition to the government and impose negative economic externalities (making mobilization more attractive). This provides conditions under which government crackdowns increase or decrease mobilization.
Voting Weights and Formateur Advantages in the Formation of Coalition Governments
Authors: Ansolabehere Stephen , Snyder James M. , Strauss Aaron B. , Ting Michael M.
Published: May 2005

Over the last two decades a large and important literature has emerged that uses game theoretic models of bargaining to study legislative coalitions. To test key predictions of these models, we examine the composition of coalition governments from 1946 and 2001. These predictions are almost always expressed in terms of parties' minimal‐integer voting weights. We calculate such weights for all parliamentary parties. In addition, we develop a statistical model that nests the predictions of many of these models of the distribution of posts. We find that for parties that join (but did not form) the government, there is a linear relationship between their share of the voting weight in parliament and their share of cabinet posts. The party that forms the government (the formateur) receives a substantial “bonus” relative to its voting weight. The latter finding is more consistent with proposal‐based bargaining models of coalition formation and suggests that parties gain disproportionate power not because of their size but because of their proposal power.
Threat, Anxiety, and Support of Antiterrorism Policies
Authors: Huddy Leonie , Feldman Stanley , Taber Charles , Lahav Gallya
Published: May 2005

The perception of threat and the experience of anxiety are distinct but related public reactions to terrorism. Anxiety increases risk aversion, potentially undercutting support for dangerous military action, consistent with terrorists' typical aims. Conversely, perceived threat increases a desire for retaliation and promotes animosity toward a threatening enemy, in line with the usual goals of affected governments. Findings from a national telephone survey confirm the differing political effects of anxiety and perceived threat. The minority of Americans who experienced high levels of anxiety in response to the September 11 attacks were less supportive of aggressive military action against terrorists, less approving of President Bush, and favored increased American isolationism. In contrast, the majority of Americans who perceived a high threat of future terrorism in the United States (but were not overly anxious) supported the Bush administration's antiterrorism policies domestically and internationally.
Immediate and Long‐Term Effects of Color Doppler Ultrasound on Myocardial Cell Apoptosis of Fetal Rats
Authors: Jia Huaping , Duan Yunyou , Cao Tiesheng , Zhao Baishan , Lv Faqin , Yuan Lijun
Published: May 2005

The objective of this article is to evaluate the safety of diagnostic color Doppler ultrasound (CDUS) on embryos by observing its effects on myocardial cell apoptosis of fetal rats. Pregnant Sprague‐Dawley rats were divided into fetal group and neonatal group according to the sample‐drawing time averagely and randomly, and each group was subdivided into control group and insonification group. The control group was sham‐insonificated, and the insonification group was insonificated by diagnostic ultrasound (3.0 MHz, Tis = 1.8, MI = 1.6) for 30 minutes. The fetal rats' hearts were removed 24 hours after insonification and the neonatal rats' hearts were removed 10 days after birth. Apoptosis cells were detected with TUNEL (in situ terminal deoxynucleotidyl transferase‐mediated D‐UTP nick end labeling), and ultrastructural changes were observed with transmission electron microscope. Myocardial cell apoptosis was significantly higher in the fetal insonification group than in the fetal control group (P < 0.05), and it was significantly higher in the fetal groups than in the neonatal groups (P < 0.05), but there was no significant difference in myocardial cell apoptosis between the neonatal groups (P < 0.05). Apoptotic changes of myocardial cells in the fetal insonification group were observed with transmission electron microscope, which showed margination, condensation of the nuclear chromatin, etc. It is concluded that apoptosis and ultrastructural changes could be induced if fetal rat's heart was irradiated continuously over 30 minutes by diagnostic CDUS, but this phenomenon would disappear after birth.
Color M‐Mode Flow Propagation Velocity and Conventional Doppler Indices in the Assessment of Diastolic Left Ventricular Function during Isometric Exercise
Authors: Chamoun Antonio J. , Xie Tianrong , McCullough Marti , Birnbaum Yochai , Ahmad Masood
Published: May 2005

Background and objective: Color M‐mode flow propagation velocity (Vp) was shown to be a preload‐independent measure of diastolic function. To study the effects of an increase in afterload induced by isometric handgrip exercise on diastolic function assessment in patients with cardiomyopathy, we measured Vp and conventional Doppler indices at baseline and at 30% of predetermined maximum handgrip strength. Methods: Twenty‐four patients with systolic dysfunction were divided into two groups: Group I comprising 12 patients with E/A < 1 (early filling velocity/atrial contraction velocity) and Group II comprising 12 patients with E/A > 1. All the patients underwent measurement of Vp, E velocity, its deceleration time (DT), A velocity, isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) at baseline and at 30% of predetermined maximum handgrip strength. Twelve healthy controls underwent these same measurements. Results: When comparing baseline to peak echocardiographic data, no significant changes were noted in Vp in any of the groups while a shift of pulsed Doppler indices of Group I toward a pattern closer to that of Group II was noted and a decrease in E velocity and E/A ratio with an increase in IVRT occurred in healthy controls. Conclusions: Color M‐mode flow propagation velocity seems to be an afterload‐independent measure of diastolic function in patients with moderate to severe cardiomyopathy while pulsed Doppler indices are more sensitive to loading conditions induced by isometric exercise.
Atrial Endocarditis—The Importance of the Regurgitant Jet Lesion
Authors: Gregory Shawn A. , Yepes Cesar B. , Byrne John G. , D’Ambra Michael N. , Chen Ming Hui
Published: May 2005

The jet lesions of valvular regurgitation or intracardiac shunts have been hypothesized to play an important role in the pathogenesis of endocarditis for many years. We describe a case of mitral valve endocarditis that involved the left atrium along the path of a jet lesion. This resulted in atrial endocarditis and pericarditis, both of which complicated her presentation and hospital course. Using transesophageal echocardiography, we were able to directly visualize the path and full extent of infection prior to surgery. Special attention should be focused upon the path of eccentric jets in order to fully define the extent of endocarditis.
Live Three‐Dimensional Transthoracic Echocardiographic Assessment of Thrombus in the Innominate Veins and Superior Vena Cava Utilizing Right Parasternal and Supraclavicular Approaches
Authors: Upendram Sailendra , Nanda Navin C. , Vengala Srinivas , Patel Vinod , Mehmood Farhat , Dod Harvinder , Bodiwala Kunal , Frans Ebenezer
Published: May 2005

We report the usefulness of right parasternal and supraclavicular live three‐dimensional transthoracic echocardiography in the delineation and follow‐up of a thrombus involving a catheter placed in superior vena cava for dialysis in an adult patient with chronic renal disease.
Clinical variability in a Japanese hereditary lymphedema type I family with an FLT4 mutation
Authors: Mizuno Seiji , Yamada Yasukazu , Yamada Kenichiro , Nomura Noriko , Wakamatsu Nobuaki
Published: May 2005

ABSTRACT  Hereditary lymphedema type I (Milroy disease) is a rare autosomal dominant disease resulting from mutations of FLT4 encoding the vascular endothelial growth factor receptor‐3. Patients develop edema of the legs and feet, resulting in chronic swelling of the lower extremities from the neonatal period. Here we report a Japanese family with 10 affected members of five generations of hereditary lymphedema type I. We identified a previously reported missense mutation of G857R in one allele of FLT4 from three affected individuals of three generations, the mother of whom presented only hemi‐lymphedema of the left foot. Thus, the clinical features of hereditary lymphedema type I caused by a FLT4 mutation are heterogeneous and it would be appropriate to consider FLT4 mutations even in a patient with hemi‐lymphedema of the foot.
Rubinstein‐Taybi syndrome (RTS) with postaxial polydactyly of the foot: 4‐year follow‐up until improvement of dysbasia
Authors: Muneuchi Gan , Kogure Tetsukuni , Sano Norihisa , Hamamoto Yusuke , Kishikawa Yuka , Tamai Motoki , Igawa Hiroharu H
Published: May 2005

ABSTRACT  Rubinstein‐Taybi syndrome (RTS), also known as ‘broad thumbs syndrome’ or ‘broad thumb‐hallux syndrome’, is a malformation syndrome characterized by the triad of broad thumbs or first toes, a peculiar facial expression called ‘comical face’ and mental retardation. Although various malformations are combined with the triad, polydactyly is rare. We treated a male patient with RTS complicated by postaxial polydactyly of the foot. His clinical course was different from typical patients with polydactyly, especially in the aspect of walking development. Osteoplasty‐combined surgery, which was ideal for anatomical reconstruction, was performed on the patient at 2 years and 11 months of age. A 4‐year follow‐up period was required until there was an improvement of dysbasia.
Acardiac acephalic twin gestation with transposition of great arteries in pump twin
Authors: Üstüner Işık , Şimşek Erhan , Kahraman Korhan , Cengiz Bora , Koç Acar
Published: May 2005

ABSTRACT  We report here a case of twin reversed arterial perfusion sequence with transposition of great arteries in the pump twin. Color Doppler and fetal echocardiographic examination revealed an acardiac, anencephalic twin without upper limbs and a pump twin with transposition of great arteries. To our knowledge despite multiple anomalies reported in the acardiac twin, major anomalies, especially of a cardiac type are extremely rare and not reported in the pump twin, which maintains circulation. Management is directed at saving the pump fetus; therefore, we believe that during sonographic exam, emphasis should be placed on associated organ anomalies or complications that may hamper viability of the pump.
Amphibian Declines in Brazil: An Overview1
Authors: Eterovick Paula Cabral , De Queiroz Carnaval Ana Carolina Oliveira , Borges‐Nojosa Diva Maria , Silvano Débora Leite , Segalla Magno Vicente , Sazima Ivan
Published: May 2005

Population declines have previously been reported for at least 31 amphibian species in Brazil, in the families Leptodactylidae (19), Hylidae (7), Centrolenidae (2), Dendrobatidae (2), and Bufonidae (1). In five Brazilian museum collections, we found no entries of new records dating back to at least 15 yr ago for 13 of these species. We suggest that these taxa be studied in more detail to verify their status and to generate basic ecological data. Museum data indicate that the remaining species have been recently found in areas of reported crashes, or elsewhere. Several apparent declines in Brazil can be associated with habitat loss, interspecific interactions, natural fluctuations, or lack of intensive sampling. Personal observations and field data also indicate possible declines in the states of Paraná and Ceará as well as in highlands within the Cerrado biome, in the state of Minas Gerais. Records suggest declines of montane and stream‐associated populations of Brazilian amphibians in apparently pristine habitats. Field work is necessary to confirm these cases and to examine whether factors associated with similar extinctions in other parts of the globe—such as pathogens and climate change—are also related to local disappearances. To clarify pending questions and perhaps circumvent new cases, it is important to invest in short‐ and long‐term field studies, and in the maintenance and expansion of museum collections.
Cambios en la Diversidad en Siete Comunidades de Anuros en los Andes de Ecuador1
Authors: Bustamante Martín R. , Ron Santiago R. , Coloma Luis A.
Published: May 2005

In the Ecuadorian Andes, populations of 24 anuran species have been reported to be in the process of decline or extinction since the late 1980s. In spite of these reports, quantitative data on population trends on anuran populations in Ecuador are scarce. We compare relative abundance and species composition in surveys conducted between 1967 and 1988 (initial surveys) with surveys conducted between March 2000 and November 2003 (recent surveys) in seven anuran communities in the Andes of Ecuador. A total of 76 anuran species was registered. In 88 populations corresponding to 73 species in seven localities, 56 of them decreased and 27 increased their relative abundances. We observed significant differences in the number of species present in the initial surveys with respect to recent surveys. In six out of seven localities we registered fewer species than previously, even though capture effort was greater in recent surveys. Differences were of higher magnitude for species with aquatic larvae (34 species in initial surveys and 17 in recent surveys). Differences were not significant for species with direct development (genus Eleutherodactylus; 28 species in initial and recent surveys). We registered increases in the upper limit of the altitudinal range for six species and nine new records for six localities.
Forecasting Climate Change Effects on Salamander Distribution in the Highlands of Central Mexico1
Authors: Parra‐Olea Gabriela , Martínez‐Meyer Enrique , De León Gerardo Pérez‐Ponce
Published: May 2005

A generalized decline of amphibian populations is occurring worldwide. The causes for such a decline are not completely understood; however, climate change has been identified as a possible cause for amphibian extinction, among others. Ecological niche modeling has proven to be a useful tool to predict potential distribution of species in the context of climatic changes. In this paper, we used the Genetic Algorithm for Rule‐set Prediction (GARP) to model the potential distributions of two species of plethodontid salamanders: Pseudoeurycea cephalica and P. leprosa. We projected their potential distributions under climatic scenarios expected in 50 yr based on a conservative scenario of global climate change and assuming a moderate dispersal ability for both species. Our analyses suggest that climate change effects may pose an additional long‐term risk to both species of plethodontid salamanders, with a more dramatic scenario in the case of P. leprosa. By the year 2050, this species may lose almost 75 percent of its distributional area, and this projection is even worse when deforestation (in the way it is occurring at present) is considered within the predicted model. Our results concur with those obtained for species with limited dispersal capability because they do not track changing climates, but rather face a loss of distributional area. The survival of these species is not secure, even though their potential distributional area falls within a considerable number of natural protected areas.
Inner‐crown Microenvironments of Two Emergent Tree Species in a Lowland Wet Forest1
Authors: Cardelús Catherine L. , Chazdon Robin L.
Published: May 2005

Vascular epiphyte communities, comprising up to 25 percent of tropical forest flora, contribute to plant diversity and thus ecosystem‐level processes; however, one of the proximal determinants of those communities, microclimate, is little studied. Here we present the first comprehensive study of microclimates in the inner crowns of two emergent tree species, Hyeronima alchorneoides and Lecythis ampla, at La Selva Biological Station, Costa Rica. We examined photon flux density, temperature, vapor pressure, and humidity in inner‐crown branches during the wet and dry seasons and during the wet‐season leafless phase of Lecythis. In both seasons, the percentage daily PFD in foliated Lecythis crowns (9%, wet season; 11%, dry season) was significantly higher than in Hyeronima crowns (5%, both seasons), with the leafless wet‐season PFD of Lecythis reaching 23 percent of full sun. Temperature and vapor pressure varied less in Hyeronima than in Lecythis crowns during the dry season. Microenvironmental conditions for epiphytes within Hyeronima crowns were more spatially and temporally homogeneous and were more buffered from ambient conditions than within Lecythis crowns. Growing conditions within the crowns of the same trees and among different trees were measurably different and are likely to affect the structure and composition of the resident epiphyte communities.
Morphological and Molecular Evidence of Arbuscular Mycorrhizal Fungal Associations in Costa Rican Epiphytic Bromeliads1
Authors: Rowe Annette R. , Pringle Anne
Published: May 2005

Arbuscular mycorrhizal fungi influence the growth, morphology, and fitness of a variety of plant species, but little is known of the arbuscular mycorrhizal (AM) fungal associations of plant species in forest canopies. Plant species' associations with AM fungi are most often elucidated by examining the roots for fungal structures; however, morphological data may provide a limited resolution on a plant's mycorrhizal status. We combined a traditional staining technique with a molecular marker (the 18S ribosomal gene) to determine whether or not a variety of epiphytic bromeliads form arbuscular mycorrhizal fungal associations. Using these methods we show that the epiphytic bromeliad Vriesea werkleana forms arbuscular mycorrhizal fungal associations with members of the genus Glomus. AM fungal sequences of this plant species formed three distinct clades nested within a larger Glomus clade; two of the clades did not group with any previously sequenced lineage of Glomus. Novel clades may represent novel species. Although Vriesea werkleana is associated with multiple AM fungal species, each individual plant is colonized by a single lineage. The combination of morphological and molecular methods provides a practical approach to the characterization of the mycorrhizal status of epiphytic bromeliads, and perhaps other tropical epiphytes.
Population Genetic Structure of Neotropical Mangrove Species on the Colombian Pacific Coast:Pelliciera rhizophorae(Pellicieraceae)1
Authors: Castillo‐Cárdenas María Fernanda , Toro‐Perea Nelson , Cárdenas‐Henao Heiber
Published: May 2005

Pelliciera rhizophoraeis a Neotropical mangrove species whose distribution is mostly restricted to the Pacific Coast, between the Gulf of Nicoya (Costa Rica) and the Esmeraldas River (Ecuador). In the Caribbean, patches ofPellicierahave been found in Nicaragua, Panama, and Colombia. The genetic variation and the population structure ofP. rhizophoraewere evaluated in six zones of the Colombian Pacific, using AFLP molecular markers. Of the 225 amplified fragments produced, 155 (69%) were polymorphic in 57 individuals ofP. rhizophoraecollected in the localities of Virudó, Charambirá, La Plata Island, Tumaco, Milagros, and Chontal. Genetic diversity within populations varied significantly, with the lowest levels of within‐population variation (Hep= 0.081 and 0.090, respectively) in La Plata Island and Tumaco; and the highest level of variation (Hep= 0.187) in Chontal. In the Colombian Pacific,P. rhizophoraewas significantly structured, with 26.5 percent of the variation found among populations, which was an evidence of substructure within populations. Genetic differentiation was not related to the geographic distance between zones. This suggests that the population dynamics ofP. rhizophoraecould be associated with historic processes influenced by ecological and environmental factors such as the movement of pollen by birds, the displacement of propagules by marine currents, and the spatial distribution of favorable habitats.
Herpetofaunal Richness and Community Structure of Offshore Islands of Sulawesi, Indonesia1
Authors: Gillespie Graeme , Howard Sam , Lockie David , Scroggie Michael , Boeadi
Published: May 2005

We examined the distribution and broad habitat associations of the herpetofauna on three offshore islands of southeast Sulawesi, Indonesia. A total of 74 amphibian and reptile taxa were recorded, comprising 13 frogs, 29 lizards, 29 snakes, 1 freshwater turtle, and 1 crocodile. Of the total taxa, 38 percent were endemic to Sulawesi, 13 were new undescribed taxa. Range extensions were also recorded for one taxon previously not known from Sulawesi. Herpetofauna of these islands is largely derived from that of mainland Sulawesi, and as for Sulawesi generally, is depauperate compared with herpetofaunal assemblages in Borneo, Java, and Thailand. Taxon richness was much higher in minimally disturbed forest and forest habitats with only moderate disturbance levels than in highly modified or disturbed habitats, such as secondary forests, plantations, and villages. Disturbed habitats were characterized by widespread, habitat generalists and human commensals. Forests were characterized by endemic and habitat‐specialist taxa. Little discrimination of taxon composition or endemism was found between minimally and moderately disturbed forest habitats. These results reaffirm the need for more general biological survey and research in this region. Taxa most likely to be displaced by human impacts tend to be endemic taxa, for which there exists little or no ecological information. The similarity in the herpetofaunal community structure between habitats with minimal and moderate disturbance levels has important implications for our understanding of ecological resilience in tropical herpetofaunal communities.
Lepidopteran Soral Crypsis on Caribbean Ferns1
Authors: Barker Michael S. , Shaw Shane W. , Hickey R. James , Rawlins John E. , Fetzner James W.
Published: May 2005

Insect‐fern interactions are not as well characterized as insect‐angiosperm interactions. For example, the imitation of unique fern structures by insects has not been observed. On a recent trip to Puerto Rico, we collected ferns that bore small Lepidoptera imitating fern sori. Herbarium specimen searches indicate that these Lepidoptera are restricted to the Caribbean on ferns with highly visible sporangia. A possible selective pressure for the evolution of lepidopteran soral crypsis is wasp parasitism, as evidence of parasitoid wasps was found. However, it is more likely that soral crypsis evolved to avoid visually oriented predators such as birds or lizards.
Population Density and Home Range Size of Red‐Rumped Agoutis (Dasyprocta leporina) Within and Outside a Natural Brazil Nut Stand in Southeastern Amazonia1
Authors: Jorge Malu S. P. , Peres Carlos A.
Published: May 2005

This study examined whether the population density and home range size of red‐rumped agoutis were affected by the spatial distribution of Brazil nut trees, at the Pinkaiti Research Station, in eastern Amazonia. Agouti densities in a Brazil nut grove were two‐fold higher and home ranges were half the size than those outside it. This indicates that the large supply of Brazil nuts results in higher densities and smaller home ranges of agoutis in this seasonally dry Amazonian forest.
Thermoeconomic Optimization of a LiBr/H2O Absorption Chiller Using Structural Method
Authors: Misra R. D. , Sahoo P. K. , Gupta A.
Published: May 2005

The optimization strategy for absorption chiller systems is generally based on thermodynamic analysis. However, the optimum, so obtained, does not always guarantee the economic optimum. In this regard, the thermoeconomics that combines the thermodynamic principles with economic parameters plays a vital role for achieving the cost effectiveness of these systems. In this paper, this technique is applied to optimize a single-effect LiBr/H2O absorption chiller system for air-conditioning applications aiming at achieving the minimum product cost. This optimization methodology is based on the relative interdependence between component irreversibility and the total system irreversibility. This relationship, known as structural coefficient, is used to evaluate the economic cost of the product of the system. The use of structural coefficient eliminates complex numerical procedures, and the optimization is achieved by sequential local optimization of the subsystems of the system. The analysis reveals that the capital cost of the optimum configuration is increased by about 33.3% from the base case, however, the additional cost is well compensated by reduced fuel cost. This is possible because of reduction of plant irreversibilities by about 47.2%.
Influence of Liquid Viscosity on the Pressure Loss and the Effectiveness of Drag-Reducing Agents in Horizontal Slug Flow
Authors: Daas Mutaz , Bleyle Derek
Published: May 2005

Measurements of drag reduction in two-phase oil-gas slug flow are presented in this study. Two types of oil with markedly different viscosities were examined in 10-cm inner diameter horizontal pipes to evaluate the influence of oil viscosity on the total pressure loss and the effectiveness of drag-reducing agents (DRAs) in reducing the pressure drop in slug flow. The total pressure drop in the 50-cP oil was always more significant than in the 2.5-cP oil, especially when increasing the gas flow rate. However, the DRA was more effective in reducing the total pressure drop in the 2.5-cP oil. Furthermore, increasing liquid velocity, thus increasing liquid volume fraction, resulted in an increase in the DRA effectiveness for both oils.
Theoretical Model of Borehole Heat Exchanger
Authors: Śliwa Tomasz , Gonet Andrzej
Published: May 2005

The paper deals with the possible use of existing oil wells for geothermal energy production. A mathematical model, describing the process of exploitation of a borehole heat exchanger, has been worked out. It was used for determining energy efficiency, employing the main parameter, i.e., flow of produced heat energy. The results of simulation of borehole heat exchanger operation in deep conditions of Iwonicz Zdrój field’s depleted deposits (Polish Carpathians) are presented. A considerable part of oil deposits in the Carpathian region—a cradle of the world’s oil industry—are to be decommissioned. Owing to the high density of population, the wells are planned to be adapted for borehole heat exchangers for clean energy production for local purposes. The decommissioning costs will be avoided.
Effects of Several Major Irreversibilities on the Thermodynamic Performance of a Regenerative MHD Power Cycle
Authors: Chen Jincan , Tyagi S. K. , Kaushik S. C. , Tiwari V. , Wu Chih
Published: May 2005

This communication presents the thermodynamic analysis along with a detailed parametric study of an irreversible regenerative MHD power cycle. The power output is adopted as the objective function and optimized with respect to the cycle temperature ratio for a typical set of operating parameters. The power output is found to be an increasing function of the effectiveness and the heat capacitance rates on the hot- and cold-side reservoirs, the regenerative effectiveness, and the compressor and generator efficiencies, while it is found to be a decreasing function of the working fluid heat capacitance rates and the Mach number. The effects of the cold-side effectiveness and heat capacitance rate are found to be more than those of the other side effectiveness and heat capacitance rates on the performance of the cycle. The effect of the compressor efficiency is found to be more than that of the generator efficiency on the power output while it is reverse in the case of thermal efficiency. It is also found that there is an optimum relation among the various heat capacitance rates at which the cycle attains the maximum performance.
SMA Hybrid Composites for Dynamic Response Abatement Applications
Authors: Turner Travis L.
Published: May 2005

A recently developed constitutive model and a finite element formulation for predicting the thermomechanical response of shape memory alloy hybrid composite (SMAHC) structures are briefly described. Attention is focused on constrained recovery behavior in this study, but the constitutive formulation is also applicable to modeling restrained or free recovery. Numerical results are shown for glass-epoxy panel specimens with embedded Nitinol actuators subjected to thermal and acoustic loads. Control of thermal buckling, random response, sonic fatigue, and noise transmission are demonstrated and compared to conventional approaches including addition of conventional composite layers and a constrained layer damping treatment. The SMAHC approach is shown to be significantly more effective in the dynamic response abatement applications than the conventional approaches. The impetus for the control is an extremely weight-efficient stiffening effect, which makes the SMAHC approach ideally suited for the difficult problem of low-frequency vibration and noise control. Extremely wideband control may be possible by combined SMAHC-conventional or SMAHC-active approaches because of the complementary control mechanisms.
Reduction of Noise Effects for In Situ Balancing of Rotors
Authors: Garvey S. D. , Williams E. J. , Cotter G. , Davies C. , Grum N.
Published: May 2005

Precision balancing any given rotor for smooth running at one or more fixed speeds requires that unbalance-originated deflections and/or forces be measured. When the rotor is balanced in situ, the standard procedure is to conduct trial runs to obtain all of the requisite information. These include at least one run with the rotor in its uncorrected state and then, for each balancing plane on the rotor, at least one run with a trial balance mass fitted to that plane. Synchronous components of deflection and/or force may be measured at numerous transducers on the machine. If the machine has B short bearings, then at any one rotor speed, the dimension of the space spanned by all of the complex vectors of synchronous stator response from the trial runs should be (at most) B. In practice, the dimension of that space is very often larger. This paper firstly demonstrates how minimal adjustments can be applied to the (complex) measured synchronous stator vibration vectors to force those vectors into a space of dimension B. Standard least-square methods can then be applied to discover a suitable set of unbalance corrections. The paper shows that in virtually all cases where the noise is high, applying this procedure of projecting the data from a given rotational speed into a space of appropriate dimension before computing the least-squares calculation is beneficial. Reductions in the balancing cost function (the scalar quantity minimized by the least squares calculation) by factors of 2 to 4 are typically obtained for realistic levels of measurement noise. At very low levels of noise, the procedure is neither beneficial nor harmful. There is a strong argument that it should always be applied.
Numerical Study of Some Nonlinear Dynamics of a Rotor Supported on a Three-Pad Tilting Pad Journal Bearing (TPJB)
Authors: Abu-Mahfouz Issam , Adams Maurice L.
Published: May 2005

The use of tilting pad journal bearings (TPJBs) has increased in the recent past due to their stabilizing effects on the rotor bearing system. However, in this paper two mechanisms capable of producing instabilities in terms of subharmonic and chaotic motions are suggested. The first one is that of a centrally loaded pad with rotor unbalance excitations. The second one represents a concentric rotor (or a vertical rotor) acted upon by centering sprigs and large unbalance excitations. Extensive numerical experimentation shows, for certain parameters, subharmonic, quasi-periodic, and chaotic motions. The pad state space trajectory, in many cases, resembles that of the two-well potential case as in Duffing’s oscillator. Time trajectories, Poincare maps, fast Fourier transform (FFT) plots, and the max Lyapunov exponent are utilized to examine the periodicity (order) of the nonsynchronous rotor orbits and pad trajectories. The TPJB problem belongs to a family of nonlinear rotor-dynamical phenomena that are potentially of a considerable value as diagnostic tools in assessing rotating machinery condition monitoring.