bluuebunny/crossref_metadata_2025 huggingface dataset:
Flying-foxes (Pteropus alecto and P. scapulatus) in the Darwin region, north Australia: patterns in camp size and structure
Authors: Vardon Michael J. , Tidemann Christopher R.
Published: January 2006

Five camps of flying-foxes (Pteropus alecto and
P. scapulatus) were monitored regularly in the Darwin
region between July 1994 and December 1997. For both species there was a
relatively consistent annual pattern in the size and age–sex structure
of camps. P. alecto appeared to be a local migrant, with
numbers in the north of the study area negatively correlated with numbers in
the south, but the movement did not involve all animals. Following births in
February there was a southward movement of adult
P. alecto in March and a return movement northward in
September–November. The extent of three vegetation types surrounding
camps had a significant effect (P< 0.05) on camp
sizein P. alecto. Sex ratios varied between
P. alecto camps, with a higher proportion of females
being found in larger camps (P< 0.001), while the
proportion of juveniles varied over the year (P<
0.05), but not between camps.
Large numbers of P. scapulatus were annual migrants to
the southern portion of the study region during July–October
1994–97, but relatively small numbers of the species were present at
other times. When integrated with other published information, the pattern
seen in this study supports the view that P. scapulatus
undertakes regular long-range movements and uses habitat in time and space
differently from P. alecto.
Haematological changes during development of the noisy miner: implications for oxygen transport
Authors: Bolton Amanda J. , Baldwin John , Lill Alan
Published: January 2006

Changes in erythrocyte numbers and size, haematocrit and blood haemoglobin
concentration in noisy miner (Manorina melanocephala)
nestlings were documented from measurements taken on wild individuals during
development. Haematocrit, whole-blood haemoglobin concentration and
erythrocyte count increased during development by factors of 2.0, 2.4 and 3.5,
respectively. The increases were continuous and occurred at fairly constant
rates throughout development, but typical adult values were not attained at
fledging. Mean erythrocyte volume and mean erythrocyte haemoglobin content
decreased continuously during nestling development. The estimated 2.4-fold
increase in oxygen carrying capacity of the blood during development stemmed
primarily from the increase in erythrocyte numbers. The reduction in
erythrocyte volume would be expected to enhance oxygen delivery by increasing
oxygen-diffusion rates. This pattern of constant change in blood parameters
resembled that reported for species with standard, rather than unusually slow,
rates of nestling development. We suggest that it reflects the fact that noisy
miner nestlings grow relatively rapidly, perhaps because it reduces the
exposure of nestlings to predation.
Food breakdown in an avian herbivore: who needs teeth?
Authors: Moore S. J.
Published: January 2006

The extent to which domestic geese (Anser anser) break
down grass, with their fast gut passage rate, limited chemical digestion of
cell walls, and the use of a gizzard, rather than a precise cutting apparatus,
such as teeth, was investigated. Whether the gizzard is the primary site of
grass breakdown, to what extent grass is broken down in the guts of geese and
whether the final size is affected by the initial ingested particle size were
all factors considered. At two discrete times geese were fed grass that had
been cut into different lengths. The resultant particle size in the excreta
was measured using an image-analysis system. The extent of grass breakdown in
different sections of the gut was also measured using image analysis on the
gut contents of geese killed after receiving a further meal of grass. The
gizzard was found to be the only site of particle size reduction and the
post-gizzard digesta particle size was remarkably consistent. This suggested
that there was a critical particle size under which the gizzard retained the
grass for further processing. The critical particle size, however, appeared to
be overridden when there was a backlog of food caused by ineffective
processing. This mechanism, in general, would ensure the achievement of
consistent processing regardless of the initial ingested particle size, while
also allowing geese to take advantage of abundant food sources when available.
It was also found that the geese more effectively processed the larger, rather
than the smaller, grass particles. Dissecting the geese after ingestion of a
further meal of large grass particles revealed that the latter were aligned
within the oesophagus along their long axis as they entered the gizzard. This
enabled the gizzard to strip the mesophyll and palisade layers from the
vascular and sclerenchyma bundles. The long axis of the small particles was
the width of the grass blade, which probably prevented this stripping of the
cells, as the vascular and sclerenchyma bundles would have been fed into the
gizzard at right angles to the gizzards’ main action. The ineffective
processing of plant material that cannot be appropriately aligned in the
gizzard has implications as to why there are few folivorous birds, as it is
possible that the gizzard cannot effectively mechanically process
dicotyledonous plant material with its reticulated veins.
Predisposing, Reinforcing, and Enabling Factors Influencing Influenza Vaccination Acceptance Among Healthcare Workers
Authors: Bautista Daniel , Vila Bernardo , Usó Ruth , Téllez María , Zanón Vicente
Published: January 2006

According to the present case-control study about influenza vaccine acceptance among hospital workers, vaccination campaigns should focus mainly on predisposing and enabling factors, emphasizing the likelihood of acquiring influenza and the positive benefits to patients, addressing concerns about vaccine efficacy or safety, and minimizing the time required for the worker to undergo vaccination.
Preventing Catheter-Associated Bloodstream Infections: A Survey of Policies for Insertion and Care of Central Venous Catheters From Hospitals in the Prevention Epicenter Program
Authors: Warren David K. , Yokoe Deborah S. , Climo Michael W. , Herwaldt Loreen A. , Noskin Gary A. , Zuccotti Gianna , Tokars Jerome I. , Perl Trish M. , Fraser Victoria J.
Published: January 2006

Objective.

To determine the extent to which evidence-based practices for the prevention of central venous catheter (CVC)-associated bloodstream infections are incorporated into the policies and practices of academic intensive care units (ICUs) in the United States and to determine variations in the policies on CVC insertion, use, and care.

Design.

A 9-page written survey of practices and policies for nontunneled CVC insertion and care.

Setting.

ICUs in 10 academic tertiary-care hospitals.

Participants.

ICU medical directors and nurse managers.

Results.

Twenty-five ICUs were surveyed (1-6 ICUs per hospital). In 80% of the units, 5 separate groups of clinicians inserted 24%-50% of all nontunneled CVCs. In 56% of the units, placement of more than two-thirds of nontunneled CVCs was performed in a single location in the hospital. Twenty units (80%) had written policies for CVC insertion. Twenty-eight percent of units had a policy requiring maximal sterile-barrier precautions when CVCs were placed, and 52% of the units had formal educational programs with regard to CVC insertion. Eighty percent of the units had a policy requiring staff to perform hand hygiene before inserting CVCs, but only 36% and 60% of the units required hand hygiene before accessing a CVC and treating the exit site, respectively.

Conclusion.

ICU policy regarding the insertion and care of CVCs varies considerably from hospital to hospital. ICUs may be able to improve patient outcome if evidence-based guidelines for CVC insertion and care are implemented.
Increased Catheter-Related Bloodstream Infection Rates After the Introduction of a New Mechanical Valve Intravenous Access Port
Authors: Maragakis Lisa L. , Bradley Karen L. , Song Xiaoyan , Beers Claire , Miller Marlene R. , Cosgrove Sara E. , Perl Trish M.
Published: January 2006

The technology of intravenous catheter access ports has evolved from open ports covered by removable caps to more-sophisticated, closed versions containing mechanical valves. We report a significant increase in catheter-related bloodstream infections after the introduction of a new needle-free positive-pressure mechanical valve intravenous access port at our institution.
An Outbreak ofSerratia marcescensBloodstream Infections Associated With Misuse of Drug Vials in a Surgical Ward
Authors: Pan Angelo , Dolcetti Lucia , Barosi Catia , Catenazzi Patrizia , Ceruti Tomaso , Ferrari Lucio , Magri Silvia , Roldan Eugenia Quiros , Soavi Laura , Carnevale Giuseppe
Published: January 2006

We report an outbreak ofSerratia marcescensbloodstream infection due to contamination of total parenteral nutrition solution by insulin or poligeline solution when single-use vials were used for multiple doses in a surgical ward. Four patients had severe sepsis, and no patient died. Multidose vials, used either correctly or incorrectly, may be associated with bloodstream infection.
Diverse staghorn corals (
Acropora
) in high-latitude Eocene assemblages: implications for the evolution of modern diversity patterns of reef corals
Authors: Wallace Carden C , Rosen Brian R
Published: January 2006

Acropora
is the most diverse genus of reef-building corals in the world today. It occurs in all three major oceans; it is restricted to latitudes 31° N–31° S, where most coral reefs occur, and reaches greatest diversity in the central Indo-Pacific. As an exemplar genus, the long-term history of
Acropora
has implications for the evolution and origins of present day biodiversity patterns of reef corals and for predicting their response to future climate change. Diversification of
Acropora
was thought to have occurred in the central Indo-Pacific within the previous two million years. We examined Eocene fossils from southern England and northern France and found evidence that precursors of up to nine of 20 currently recognized
Acropora
species groups existed 49–34 Myr, at palaeolatitudes far higher than current limits, to 51° N. We propose that pre-existing diversity contributed to later rapid speciation in this important functional group of corals.
Lonely hearts or sex in the city? Density-dependent effects in mating systems
Authors: Kokko Hanna , Rankin Daniel J
Published: January 2006

Two very basic ideas in sexual selection are heavily influenced by numbers of potential mates: the evolution of anisogamy, leading to sex role differentiation, and the frequency dependence of reproductive success that tends to equalize primary sex ratios. However, being explicit about the numbers of potential mates is not typical to most evolutionary theory of sexual selection. Here, we argue that this may prevent us from finding the appropriate ecological equilibria that determine the evolutionary endpoints of selection. We review both theoretical and empirical advances on how population density may influence aspects of mating systems such as intrasexual competition, female choice or resistance, and parental care. Density can have strong effects on selective pressures, whether or not there is phenotypic plasticity in individual strategies with respect to density. Mating skew may either increase or decrease with density, which may be aided or counteracted by changes in female behaviour. Switchpoints between alternative mating strategies can be density dependent, and mate encounter rates may influence mate choice (including mutual mate choice), multiple mating, female resistance to male mating attempts, mate searching, mate guarding, parental care, and the probability of divorce. Considering density-dependent selection may be essential for understanding how populations can persist at all despite sexual conflict, but simple models seem to fail to predict the diversity of observed responses in nature. This highlights the importance of considering the interaction between mating systems and population dynamics, and we strongly encourage further work in this area.
Sexual conflict over mating and fertilization: an overview
Authors: Parker G.A
Published: January 2006

Sexual conflict is a conflict between the evolutionary interests of individuals of the two sexes. The sexes can have different trait optima but this need not imply conflict if their optima can be attained simultaneously. Conflict requires an interaction between males and females (e.g. mating or parental care), such that the optimal outcomes for each sex cannot be achieved simultaneously. It is important to distinguish between battleground models, which define the parameter space for conflict and resolution models, which seek solutions for how conflicts are resolved. Overt behavioural conflict may or may not be manifest at resolution. Following Fisherian principles, an immediate (i.e. direct) benefit to a male that has a direct cost to his female partner can have an indirect benefit to the female via her male progeny. Female resistance to mating has been claimed to represent concurrence rather than conflict, due to female benefits via sons (males with low mating advantage are screened out by resistance). However, the weight of current evidence (both theoretical and empirical) supports sexual conflict for many cases. I review (i) conflicts over mate quality, encounters between males and females of genetically diverged subpopulations, mating rate and inbreeding, (ii) the special features of postcopulatory sexual conflict and (iii) some general features of importance for conflict resolution.
Rapid evolution of reproductive proteins in abalone andDrosophila
Authors: Panhuis Tami M , Clark Nathaniel L , Swanson Willie J
Published: January 2006

Observations from different taxa, including plants, protozoa, insects and mammals, indicate that proteins involved in reproduction evolve rapidly. Several models of adaptive evolution have been proposed to explain this phenomenon, such as sexual conflict, sexual selection, self versus non-self recognition and pathogen resistance. Here we discuss the potential role of sexual conflict in the rapid evolution of reproductive genes in two different animal systems, abalone (Haliotis) andDrosophila. In abalone, we reveal how specific interacting sperm–egg proteins were identified and discuss this identification in the light of models for rapid protein evolution and speciation. ForDrosophila, we describe the genomic approaches taken to identify male accessory gland proteins and female reproductive tract proteins. Patterns of protein evolution from both abalone andDrosophilasupport the predicted patterns of rapid protein evolution driven by sexual conflict. We stress however that other selective pressures may contribute to the rapid evolution that is observed. We conclude that the key to distinguishing between sexual conflict and other mechanisms of protein evolution will be an integration of genetic, experimental and theoretical data.
Magnetic resonance imaging, clinical manifestations, and management of Rathke's cleft cyst
Authors: Nishioka Hiroshi , Haraoka Jo , Izawa Hitoshi , Ikeda Yukio
Published: January 2006

Objective  The management of Rathke's cleft cyst (RCC), particularly in patients with no symptoms or with only minor endocrinopathies, has not yet been established. We retrospectively analysed patients with RCC to elucidate correlations between the clinical manifestations, magnetic resonance imaging (MRI) findings, histology and therapeutic outcomes.

Methods  We retrospectively studied 37 patients with RCC, who underwent computed tomography (CT), MRI and endocrinological examinations, of whom 27 patients underwent surgical intervention.

Results  The presence of frontal headaches and anterior pituitary dysfunction was unrelated to the cyst size but was more frequent in patients with high‐ and isointensity cysts on T1‐weighted images (WIs) than those with low‐intensity cysts (P = 0·0159 and P = 0·0249, respectively). All three patients with posterior pituitary dysfunction had a high‐intensity cyst on T1‐WI (P = 0·0385), whereas pituitary dysfunction was not observed in patients with a low‐intensity cyst on T1‐WI. In contrast to the excellent therapeutic outcomes with regard to visual disturbance and hyperprolactinaemia, recovery of pituitary dysfunction was rare; only three of nine patients with hypopituitarism showed improvement. Among six patients with histologically recognized intense chronic inflammation in the cyst wall, five patients had an RCC of T1 high intensity (P = 0·0161), two patients had distinct rim enhancement on MRI (P = 0·0060), all patients had frontal headaches (P = 0·0130), and four patients had associated hypopituitarism (P = 0·0243), none of which improved after surgical intervention.

Conclusion  RCCs of high‐ and isointensity on T1‐weighted images, which contain mucous material within the cyst, may be associated with chronic inflammation that can potentially cause irreversible endocrine dysfunction. In asymptomatic patients with RCCs of these MR intensities, close follow‐up with precise endocrinological evaluation and gadolinium‐enhanced MRI is necessary to avoid occult progression of the inflammation.
The IGF‐I system and the renal and haemodynamic effects of losartan in normotensive patients with type 2 diabetes mellitus: a randomized clinical trial
Authors: Zandbergen Adrienne A. M. , Lamberts Steven W. J. , Baggen Marinus G. A. , Janssen Joop A. M. J. L. , Boersma Eric , Bootsma Aart H.
Published: January 2006

Objective  Losartan has been shown to protect the diabetic kidney, at least partly independent of changes in blood pressure. Imbalances in the IGF‐I system are associated with the development of diabetic nephropathy. We investigated whether renal as well as haemodynamic effects of losartan are associated with changes in the IGF‐I system in normotensive patients with type 2 diabetes mellitus (T2DM).

Design and patients  This randomized, double‐blind placebo‐controlled clinical trial involved 74 normotensive patients with T2DM and microalbuminuria. Thirty‐eight patients were assigned to receive losartan and 36 patients were assigned to receive placebo for 10 weeks.

Measurements  Serum levels of total and free IGF‐I, IGFBP‐3, creatinine and haemoglobin A1c (HbA1c), as well as urinary albumin excretion rate, creatinine clearance and blood pressure, were measured prior to the start of treatment and after 10 weeks of treatment.

Results  At baseline, serum levels of IGFBP‐3 were elevated and serum levels of free IGF‐I were reduced. Losartan tended to reduce IGFBP‐3 levels and to increase free IGF‐I levels, although neither effect was statistically significant. These effects were more pronounced in a subanalysis of 18 losartan‐treated patients with stable metabolic parameters, with a decrease in IGFBP‐3 from 133·2 to 122·6 nmol/l (P = 0·006) and an increase in free IGF‐I levels by 8% (ns). Serum levels of total IGF‐I were unaffected. The change in IGFBP‐3 was inversely correlated to the change in creatinine clearance (r = –0·4; P = 0·02). Total and free IGF‐I inversely correlated to systolic blood pressure (r = –0·46; P = 0·007 and r = 0·26; P = 0·14 respectively). Furthermore, changes in total IGF‐I and IGFBP‐3 correlated to changes in serum creatinine levels in the metabolically stable patients (r = 0·58, P = 0·02 and r = 0·6, P = 0·01, respectively). Changes in the IGF‐I system were unrelated to a reduction in microalbuminuria associated with losartan.

Conclusions  Losartan lowered the elevated levels of IGFBP‐3, although only significantly in the metabolically stable patients. A tendency towards an increase in free IGF‐I levels was also observed, but this change was small and not statistically significant. These changes were not related to reduction in microalbuminuria, but might contribute to effects of losartan on creatinine clearance and blood pressure of losartan in normotensive patients with T2DM.
Effectiveness and tolerability of 3‐year lanreotide Autogel® treatment in patients with acromegaly
Authors: Caron Philippe , Cogne Muriel , Raingeard Isabelle , Bex‐Bachellerie Véronique , Kuhn Jean Marc
Published: January 2006

Objective  During short‐term treatment, monthly subcutaneous injections of lanreotide Autogel® are effective in controlling GH/IGF‐1 hypersecretion and are well tolerated in patients with acromegaly. This study reports the effectiveness and the tolerability of lanreotide Autogel for at least 3 years in acromegalic patients.

Patients  Fourteen patients (nine females, five males) were treated with titrated doses of lanreotide Autogel.

Design  This clinical study was an extension of a previous trial. After three fixed‐dose lanreotide Autogel injections, treatment was adjusted according to mean GH and IGF‐I levels. After 3 years of treatment, patients were receiving 120 (n = 7), 90 (n = 2) and 60 mg (n = 4) monthly injections of lanreotide Autogel.

Measurements  Acromegalic symptoms, GH and IGF‐1 concentrations were analysed at the end of lanreotide microparticle treatment, and after 4, 8, 12, 24, 30 and 36 months of lanreotide Autogel therapy. Tolerance and side‐effects were monitored throughout the 3‐year study.

Results  Hormonal control (GH ≤ 2·5 µg/l and age‐ and sex‐normalized IGF‐1) was achieved in six (46%) patients. With the exception of an unrelated death due to pulmonary embolism, no patient withdrew from study. The number of patients reporting digestive adverse events was seven (12 episodes) for the fixed‐dose period, and four (eight episodes), two (six episodes) and one (three episodes) at the end of the first, second and third year of treatment, respectively. Persistent induration at the injection sites was reported by two patients, and histological findings were consistent with benign injection‐site granulomas. New cholelithiasis or sludge occurred in five (35%) patients during the lanreotide Autogel treatment.

Conclusion  This 3‐year study shows that lanreotide Autogel is effective in controlling GH/IGF‐1 hypersecretion and is well tolerated during long‐term treatment of patients with acromegaly.
Low‐dose ACTH (1 µg) salivary test: a potential alternative to the classical blood test
Authors: Marcus‐Perlman Y. , Tordjman K. , Greenman Y. , Limor R. , Shenkerman G. , Osher E. , Stern N.
Published: January 2006

Objectives  Salivary cortisol is unaffected by cortisol binding globulin (CBG) and hence allows CBG‐related variations in serum total cortisol to be bypassed. We assessed whether or not salivary cortisol can be used for the low‐dose (1 µg) ACTH test in subjects with presumed normal and elevated levels of CBG.

Patients/methods  We measured serum and salivary cortisol responses to intravenous administration of 1 µg ACTH in 14 healthy volunteers, 14 ‘hyperoestrogenic’ women [in their first or early second trimester of pregnancy, using oral contraceptives (OC) or on hormone replacement therapy (HRT)] and 10 patients with secondary hypoadrenalism. Cortisol levels were recorded before as well as 30 and 60 min (+30; +60 min) after ACTH administration.

Results  Baseline salivary cortisol did not differ significantly between the hypoadrenal and healthy patients (7·11 ± 1·4 and 12·13 ± 1·59 nmol/l; P = 0·48) but there was a significant difference between hypoadrenal and hyperoestrogenic patients (18·94 ± 3·44 nmol/l; P = 0·01). The largest difference between hypoadrenal patients and healthy individuals was observed at +30 min (9·16 ± 2·8, 52·65 ± 8·78 and 48·81 ± 6·9 nmol/l, in the hypoadrenal, healthy and hyperoestrogenic patients, respectively; P < 0·05). At this time‐point values < 24·28 nmol/l were found in all hypoadrenal patients and cortisol levels ≥ 27·6 nmol/l were found in 26 out of 28 healthy volunteers. ACTH‐stimulated serum cortisol but not salivary cortisol was significantly higher in hyperoestrogenic women than in the healthy volunteers at either +30 or +60 min.

Conclusions  The salivary low‐dose ACTH test yields results that parallel the response of circulating cortisol to ACTH and may provide an alternative to the blood test, particularly in situations where increased CBG levels complicate the changes in serum cortisol levels.
Using Markov chain successional models backwards
Authors: SOLOW ANDREW R. , SMITH WOOLLCOTT K.
Published: January 2006

Markov chains are commonly used to model succession in plant and animal communities. Once fitted to data, these models are typically used to address ecological issues concerning future successional states. In some situations it may be of interest to use the present successional state to reconstruct past conditions.

The properties of a time‐reversed Markov chain are reviewed and used to provide an expression for the conditional probability distribution of the most recent time that the chain was in a particular successional state given its present state.

The estimation of this conditional probability is discussed and a parametric bootstrap is described for constructing a confidence interval.

The calculations are illustrated using a published Markov chain model of succession in a rocky subtidal community.

Synthesis and applications. The term succession refers to the progressive changes over time in the state of an ecological community. Although most analyses of succession focus on characterizing the future, in some situations interest centres on reconstructing the past. For example, forensic entomologists are commonly interested in estimating time of death from the insect community present on a corpse. When succession can be modelled as a Markov chain, the results obtained here can be used for this kind of reconstruction.
Association of candidal activity with denture use and salivary flow in symptom‐free adults over 60 years1
Authors: IKEBE K. , MORII K. , MATSUDA K. , HATA K. , NOKUBI T.
Published: January 2006

summary  The purpose of this study was to examine the amount of palatal mucosa Candida species associated with denture use and stimulated salivary flow in symptom‐free adults over 60 years. The subjects were 351 (189 men and 162 women) independently living elderly people with a mean age of 66·7 ± 4·3 (SD) years. Candidal activity of palatal mucosa was evaluated by the pH change in the medium that was associated with the acid production of the yeast. Subjects whose stimulated salivary flow rate was less than 0.5ml/min were placed in the hyposalivation group. A multiple logistic regression analysis was used to determine if an independent variable was statistically significant after controlling for other variables. Candidal activity of the palatal mucosa was significantly associated with the dental status of the maxillae (Kruskal‐Wallis test, P < 0·001), but was not significantly associated with age or drug intake. In maxillary denture wearers, Candidal activity of palatal mucosa had a significantly positive correlation with candidal activity of tissue fitting surfaces of maxillary dentures (r = 0·806, P < 0·001). A multiple logistic regression analysis showed that high candidal activity of the palate was significantly associated with being male and wearing maxillary removable dentures. Stimulated salivary flow rate was likely to be negatively related to high candidal activity (P = 0·07). This study suggests that the activity of Candida species in the oral cavity is associated with the wearing of removable dentures and stimulated salivary flow, independent of age or gender even in the relatively healthy elderly.
Hardness of enamel exposed to Coca‐Cola® and artificial saliva
Authors: DEVLIN H. , BASSIOUNY M. A. , BOSTON D.
Published: January 2006

summary  The purpose of this study was to determine the rate of change in indentation hardness of enamel in permanent teeth exposed to Coca‐Cola®. In a further experiment, the ability of a commercially available artificial saliva to remineralize enamel treated with Coca‐Cola® was tested. Ten enamel specimens were randomly chosen to be treated with Coca‐Cola® (experimental groups) and seven with water (control group). The fluids were applied for 1, 2, 3 h and overnight (15 h), washed off with a few drops of water and the moist enamel indentation hardness tested after each interval. With Coca‐Cola® treatment, the mean enamel hardness was 92·6% (s.d. = 7·9) of the original baseline hardness after 1 h, 93·25% (s.d. = 10·15) after 2 h, 85·7% (s.d. = 12·03) after 3 h and 80·3% after 15 h. The mean indentation hardness of control specimens treated with water was 108·7% (s.d. = 16·09) of the original hardness after 1 h, 99·09% (s.d. = 18·98) after 2 h, 98·97% (s.d. =11·24) after 3 h and 98·42% (s.d. = 22·78) after 15 h. In a separate experiment, the hardness of 9 enamel specimens was tested, as previously described, before and after treatment with Coca‐Cola® overnight and again after application of artificial saliva for 3 min. Coca‐Cola® reduced the mean indentation hardness of enamel in the teeth, but the hardness was partially restored with artificial saliva (Salivart®) and increased by 18% from the demineralized enamel hardness.
In vitro differences of stress concentrations for internal and external hex implant–abutment connections: a short communication
Authors: MAEDA Y. , SATOH T. , SOGO M.
Published: January 2006

summary  The aim of this study was to clarify the difference in the stress distribution patterns between implants with external‐hex or internal‐hex connection systems using in vitro models. Three 13 mm fixtures with external‐hex and internal‐hex connections were installed into an acrylic bone analogue. One piece abutments of 7 mm height was connected. Strain gauges were attached to the abutment surface, and the cervical and fixture tip areas of the bone analogue surface. Vertical and horizontal load applied was 30 N. Data were normalized for each model by obtaining values relative to the sum of the three values. Almost the same force distribution pattern was found under vertical load in both systems. Fixtures with external‐hex showed an increase in strain at the cervical area under horizontal load, while in internal‐hex fixtures the strain was at the fixture tip area. Within limitations of our model study, it was suggested that fixtures with internal‐hex showed widely spread force distribution down to the fixture tip compared with external hex ones.
Diversity, distribution and exchange of blood parasites meeting at an avian moving contact zone
Authors: REULLIER JULIEN , PÉREZ‐TRIS JAVIER , BENSCH STAFFAN , SECONDI JEAN
Published: January 2006

Research on contact zones has paid relatively little attention to host–parasite interactions, although these situations have important but different implications depending on whether one considers the host or the parasite's perspective. We investigated both the role of a host contact zone in parasite expansion and whether parasites could influence contact zone dynamics. We studied the diversity and the patterns of parasite exchange (genera Haemoproteus and Plasmodium) infecting two parapatric sibling passerines meeting at a moving contact zone in western Europe. We amplified and sequenced a fragment of the parasite cytochrome b gene. The expanding host harboured more diverse parasites, which might indicate a superior ability to face a diverse parasite fauna than the receding host. Prevalence was very high in both hosts, due to the frequent occurrence of two sister Haemoproteus lineages. Despite the recent movement of the contact zone, these two parasites fitted almost perfectly to the geographic range of their main host species. Yet, we found several cases of cross‐species infection in sympatric areas and evidences of asymmetrical spreading of parasites from the expanding host towards the receding host. Altogether, our results suggest that the host contact zone mainly acts as a barrier to parasite expansion even if recurrent host shifts are observed. Besides, they also support the idea that parasite‐mediated competition might contribute to the displacement of hosts’ contact zones, thereby emphasizing the role of parasitism on the population dynamics of sympatric species.
Contrasting phylogeographical patterns between mainland and island taxa of the Pinus luchuensis complex
Authors: CHIANG Y.‐C. , HUNG K.‐H. , SCHAAL B. A. , GE X.‐J. , HSU T.‐W. , CHIANG T.‐Y.
Published: January 2006

Species whose geographical distribution encompasses both mainland and island populations provide an ideal system for examining isolation and genetic divergence. In this study, paternally transmitted chloroplast DNA (cpDNA) and maternally transmitted mitochondrial DNA (mtDNA) were used to estimate population structure and phylogeography of Pinus luchuensis, a species found in eastern China (ssp. hwangshanensis), Taiwan (ssp. taiwanensis), and the Ryukyu Archipelago (ssp. luchuensis). Gene genealogies of both mtDNA and cpDNA reveal two major lineages. Molecular dating indicates that these lineages diverged before the colonization of P. luchuensis subspecies in Taiwan and the Ryukyu Archipelago. Both mtDNA and cpDNA show a lack of correspondence between molecular phylogeny and subspecies designation. Phylogeographical analysis suggests that paraphyly of the subspecies is the result of recent divergence rather than secondary contacts. In spite of the short divergence history of P. luchuensis on islands, the island populations show the same degree of genetic divergence as mainland populations. Low levels of genetic diversity in the mainland ssp. hwangshanensis suggest demographic bottlenecks. In contrast, the high heterogeneity of genetic composition for island populations is likely to be associated with a history of multiple colonization from the mainland. The spatial apportionment of organelle DNA polymorphisms is consistent with a pattern of stepwise colonization on island populations.
A ‘dirty’ business: testing the limitations of terminal restriction fragment length polymorphism (TRFLP) analysis of soil fungi
Authors: AVIS PETER G. , DICKIE IAN A. , MUELLER GREGORY M.
Published: January 2006

Terminal restriction fragment length polymorphism (TRFLP) is an increasingly popular method in molecular ecology. However, several key limitations of this method have not been fully examined especially when used to study fungi. We investigated the impact of spore contamination, intracollection ribosomal DNA internal transcribed spacer (ITS) region variation, and conserved restriction enzyme recognition loci on the results produced by TRFLP to characterize soil fungal communities. We find that (i) the potential for nontarget structures such as spores to contribute DNA to target sample extractions is high; (ii) multiple fragments (i.e. ‘extra peaks’) per PCR primer‐restriction enzyme combination can be detected that are caused by restriction enzyme inefficiency and intracollection ribosomal DNA ITS variation; and (iii) restriction enzyme digestion in conserved vs. variable gene regions leads to different characterizations of community diversity. Based on these results, we suggest that studies employing TRFLP need to include information from known, identified fungi from sites within which studies take place and not to rely only on TRFLP profiles as a short cut to fungal community description.
Identification and functional characterization of EhClC‐A, an Entamoeba histolytica ClC chloride channel located at plasma membrane
Authors: Salas‐Casas Andrés , Ponce‐Balderas Arturo , García‐Pérez Rosa María , Cortés‐Reynosa Pedro , Gamba Gerardo , Orozco Esther , Rodríguez Mario A.
Published: January 2006

ClC chloride channels perform a wide variety of physiological functions and they had been characterized in animals, yeast, plants and bacteria but not in protozoa. By blast search we found in Entamoeba histolytica, the protozoan responsible for human amoebiasis, two genes (Ehclc‐A and Ehclc‐B) encoding for putative polypeptides with 25–30% identity to ClC chloride channels of several organisms. Reverse transcription polymerase chain reaction (RT‐PCR) experiments showed that both genes are transcribed in trophozoites. Phylogenetic analysis revealed that EhClC‐A and EhClC‐B polypeptides belong to the eukaryotic branch of plasma membrane ClCs. Specific antibodies against EhClC‐A confirmed that it is located at the trophozoite plasma membrane. Xenopus laevis oocytes microinjected with Ehclc‐A cRNA elicited anion currents not detected in oocytes microinjected with water. Induced currents were inwardly rectifying and had a permeability sequence of Cl– > Br– > I– > F– >> NO3–. The chloride channel blocker 4‐acetamido‐4′isothiocyanostilbene‐2, 2′‐disulphonic acid (SITS) strongly inhibited the oocytes anion currents and trophozoites growth. Experiments at diverse pHs suggested that EhClC‐A is not a Cl–/H+ exchanger, but it is an ion channel that could be involved in pH regulation. EhClC‐A may also participate in cell volume regulation. As far as we know, EhClC‐A is the first chloride channel characterized in protozoa.
GPS measurements of ground deformation induced by water level variations into a granitic aquifer (French Brittany)
Authors: Moreau Frédérique , Dauteuil Olivier , Bour Olivier , Gavrilenko Pierre
Published: January 2006

We used two semi‐permanent GPS receivers with differential configuration to measure the hydrological subsidence of an aquifer used for water supply, located on a fractured granitic area. The time series of the vertical deformation measurements of the ground surface show a variation of 2 cm between winter and summer. We investigate the relationship between this vertical deformation and hydraulic head variations. We show that this kind of GPS survey allows characterizing part of the hydrological properties of such a heterogeneous aquifer. This is thus a new approach of time continuous monitoring of the deformation related to hydrogeological processes.
Saxo‐Thuringia in the Variscan belt from a geodynamic point of view
Authors: Sommer Max , Katzung Gerhard
Published: January 2006

Saxo‐Thuringia is a suture bounded part of the Variscan belt in central Europe and represents a fragment of the Armorica microplate. Structural investigations and a critical review of other geologic data allow the reconstruction of its geodynamic history. Two south‐dipping subduction zones, corresponding to the Rheno‐Herzynian and the Tepla sutures, delimited Saxo‐Thuringia before the Variscan orogeny. As a result of the continental collision between Avalonia to the north and a further fragment of Armorica to the south, both outer realms of Saxo‐Thuringia record high‐grade metamorphism and a subsequent uplift between 340 and 310 Ma. Contemporaneously, the low‐grade metamorphic internal zone of Saxo‐Thuringia records thrust contraction of the late Pre‐Cambrian basement and the formation of a fold belt in the overlaying Palaeozoic deposits. Two pre‐Variscan tectonic imprints are distinguishable: (1) the consolidation of late Pre‐Cambrian basement in the Cadomian–Avalonian belt and (2) a Cambrian and early Ordovician rift setting related to the opening of the Rheic ocean and the fragmentation and separation of Armorica.
Crustal thickening and lateral flow during compression of hot lithospheres, with particular reference to Precambrian times
Authors: Cagnard Florence , Durrieu Nicolas , Gapais Denis , Brun Jean‐Pierre , Ehlers Carl
Published: January 2006

Many ancient deformation belts, especially of Archean and Palaeoproterozoic age, show large areas marked by primary flat‐lying fabrics associated with rather monotonous metamorphic conditions of HTLP type and affected by steep transpressive zones involving vertical stretch. These features do not support strain localization along large‐scale thrusts and (or) extensional detachments, as common in modern orogens. Instead, they are consistent with hot and weak lithospheres where gravity‐driven horizontal flow may compete with distributed thickening from early stages of collisional processes. Relevant deformation features are reviewed and highlighted by lithosphere‐scale analogue models involving low‐viscosity lower crust and sub‐Moho mantle. Both nature and models argue that compression of such lithospheres may induce combined distributed thickening and lateral channel flow of the ductile crust accommodated by transpressive zones.
Uniform Permian40Ar/39Ar detrital mica ages in the eastern Qaidam Basin (NW China): where is the source?
Authors: Rieser Andrea B. , Liu Yongjiang , Genser Johann , Neubauer Franz , Handler Robert , Ge Xiao‐Hong
Published: January 2006

New single‐grain40Ar/39Ar detrital white‐mica ages from the Lulehe section at the eastern Qaidam Basin yield uniform Permian ages between 250 ± 3 and 279 ± 3 Ma throughout the whole Cenozoic sequence. This is inconsistent with the present hinterland, which is composed of early Palaeozoic metamorphic units with subordinate early Palaeozoic and few Permian granites. The new data indicate that Permian tectonic units are likely more widespread at the north‐eastern margin of the Tibetan plateau as known at present, particularly within the Qilian Mountains. The preferred explanation is that the Qaidam block represents a rigid indenter, which indented during late Tertiary times into early Palaeozoic orogenic units. This is consistent with recent findings of a NW‐trending sinistral Permian ductile shear zone and a dextral, NW‐trending Tertiary fault system close to the north‐eastern margin of the Qaidam Basin.
Reconstructing asymmetrical reproductive character displacement in a periodical cicada contact zone
Authors: Cooley John R. , Marshall David C. , Hill Kathy B. R. , Simon Chris
Published: January 2006

Selection against costly reproductive interactions can lead to reproductive character displacement (RCD). We use information from patterns of displacement and inferences about predisplacement character states to investigate causes of RCD in periodical cicadas. The 13-year periodical cicada Magicicada neotredecim exhibits RCD and strong reproductive isolation in sympatry with a closely related 13-year species, Magicicada tredecim. Displacement is asymmetrical, because no corresponding pattern of character displacement exists within M. tredecim. Results from playback and hybridization experiments strongly suggest that sexual interactions between members of these species were possible at initial contact. Given these patterns, we evaluate potential sources of selection for displacement. One possible source is ‘acoustical interference’, or mate-location inefficiencies caused by the presence of heterospecifics. Acoustical interference combined with the species-specificity of song pitch and preference appears to predict the observed asymmetrical pattern of RCD in Magicicada. However, acoustical interference does not appear to be a complete explanation for displacement in Magicicada, because our experiments suggest a significant potential for direct sexual interactions between these species before displacement. Another possible source of selection for displacement is hybrid failure. We evaluate the attractiveness of inferred hybrid mating signals, and we examine the viability of hybrid eggs. Neither of these shows strong evidence of hybrid inferiority. We conclude by presenting a model of hybrid failure related to life cycle differences in Magicicada.
Modulation of sexual signalling by immune challenged male mealworm beetles (Tenebrio molitor, L.): evidence for terminal investment and dishonesty
Authors: Sadd B. , Holman L. , Armitage H. , Lock F. , Marland R. , Siva-jothy M. T.
Published: January 2006

Organisms partition resources into life-history traits in order to maximise fitness over their expected lifespan. For the males of many species fitness is determined by qualitative and quantitative aspects of costly sexual signals: The notion that epigamic traits are costly forms the cornerstone of those theories that propose parasites drive sexual selection. Consequently studies examining this notion assume sexual signalling is honest (i.e. driven by cost) when they seek to identify correlations or causal links between male immune function and attractiveness. We demonstrate that immune challenged males of the mealworm beetle, Tenebrio molitor, increased their investment in epigamic pheromone signals: these males became significantly more attractive to females whilst increasing the activity of a key immune effector system. In other words males increase terminal reproductive effort (invest in attractiveness) in response to a survival threat (immune insult). Consequently the signal preferred by the female is dishonest when considering the male's condition.
A new route to the evolution of cooperation
Authors: Santos F. C. , Pacheco J. M.
Published: January 2006

The Prisoner's Dilemma (PD) constitutes a widely used metaphor to investigate problems related to the evolution of cooperation. Whenever evolution takes place in well-mixed populations engaged in single rounds of the PD, cooperators cannot resist invasion by defectors, a feature, which is somewhat alleviated whenever populations are spatially distributed. In both cases the populations are characterized by a homogeneous pattern of connectivity, in which every individual is equivalent, sharing the same number of neighbours. Recently, compelling evidence has been accumulated on the strong heterogeneous nature of the network of contacts between individuals in populations. Here we describe the networks of contacts in terms of graphs and show that heterogeneity provides a new mechanism for cooperation to survive. Specifically, we show that cooperators are capable of exploring the heterogeneity of the population structure to become evolutionary competitive. As a result, cooperation becomes the dominating trait in scale-free networks of contacts in which the few highly connected individuals are directly inter-connected, in this way contributing to self-sustain cooperation.
Distortion of symmetrical introgression in a hybrid zone: evidence for locus-specific selection and uni-directional range expansion
Authors: Johannesen J. , Johannesen B. , Griebeler E. M. , Baran I. , Tunç M. R. , Kiefer A. , Veith M.
Published: January 2006

The fate of species integrity upon natural hybridization depends on the interaction between selection and dispersal. The relative significance of these processes may be studied in the initial phase of contact before selection and gene flow reach equilibrium. Here we study a hybrid zone of two salamander species, Lyciasalamandra antalyana and Lyciasalamandra billae, at the initial phase of hybridization. We quantify the degree and mode of introgression using nuclear and mtDNA markers. The hybrid zone can be characterized as an abrupt transition zone, the central hybrid zone being only c. 400 m, but introgressed genes were traced up to 3 km. Introgression was traced in both sexes but gene flow may be slightly male-biased. Indirect evidence suggests that hybrid males are less viable than females. Introgression occurred at two levels: (1) locus-specific selection led to different allelic introgression patterns independent of species, while (2) asymmetrical species-level introgression occurred predominately from L. antalyana to L. billae due to range expansion of the former. This indicates that foreign genes can be incorporated into novel genomic environments, which in turn may contribute to the great diversity of morphological variants in Lyciasalamandra.