The ecological benefits of larger colony size may promote polygyny in ants.

How polygyny evolved in social insect societies is a long-standing question. This phenomenon, which is functionally similar to communal breeding in vertebrates, occurs when several queens come together in the same nest to lay eggs that are raised by workers. As a consequence, polygyny drastically reduces genetic relatedness among nestmates. It has been suggested that the short-term benefits procured by group living may outweigh the costs of sharing the same nesting site and thus contribute to organisms rearing unrelated individuals. However, tests of this hypothesis are still limited. To examine the evolutionary emergence of polygyny, we reviewed the literature to build a data set containing life-history traits for 149 Palearctic ant species and combined this data set with a reconstructed phylogeny. We show that monogyny is the ancestral state and that polygyny has evolved secondarily and independently throughout the phylogenetic tree. The occurrence of polygyny is significantly correlated with larger colony size, dependent colony founding and ecological dominance. Although polydomy (when a colony simultaneously uses several connected nests) tends to occur more frequently in polygynous species, this trend is not significant when phylogenetic history is accounted for. Overall, our results indicate that polygyny may have evolved in ants in spite of the reduction in nestmate relatedness because large colony size provides immediate ecological advantages, such as the more efficient use of temporal food resources. We suggest that the competitive context of ant communities may have provided the conditions necessary for the evolution of polygyny in some clades.

A cost analysis of postoperative management in endometrial cancer patients treated by robotics versus laparoscopic approach.

OBJECTIVE: The purpose of this study is to compare postoperative pain management and costs in endometrial cancer patients who had a robotic-assisted or laparoscopic-assisted hysterectomy. METHODS: This is a retrospective cohort study of all endometrial cancer patients from 9/2005 to 6/2010 who had a completed robotic-assisted or laparoscopic-assisted hysterectomy. All surgeries were performed by gynecologic oncologists on the da Vinci S surgical system. Demographic data, patient-recorded pain scores, pain-management interventions, and postoperative pain medication costs were compared. Data was analyzed using Student's t-tests and Pearson's χ(2) tests in SPSS. RESULTS: Two-hundred fifteen (101 robotic and 114 laparoscopic) patients met the inclusion criteria. There were no significant differences between the groups in age, BMI, clinical stage, comorbidities, lymph nodes retrieved, and the number of narcotic vs. non-narcotic drug interventions administered. Robotic patients had a lower number of initial drug interventions (21 vs. 52; P<.001) and total drug interventions (162 vs. 219; P<.001) than laparoscopic patients. Robotics had a lower initial pain score (2.1 vs. 3.0; P=.012). There was a 50% reduction in the pain medication cost on the day of surgery for robotic patients ($12.24 vs. $24.45; P<.01), and a 56% cost reduction for the rest of their length of stay ($3.63 vs. $8.17; P<.01). CONCLUSION: Endometrial cancer patients who have robotic surgery experience less initial postoperative pain and have fewer drug interventions. The cost associated for their pain management represents a savings of greater than 50%. These factors demonstrate the value of robotic surgery in regard to postoperative pain management by delivering higher quality care at a lower cost.

A psychosocial evaluation process for living liver donors: the University of Rochester model.

OBJECTIVE: The donation of livers by living donors entails complex processes, both surgically and psychosocially, potentially involving risks in both domains. Thorough psychosocial evaluation is necessary to minimize those risks, yet little has been written about the donor assessment process. This article describes one such process, utilized by a transplant program in upstate New York. METHOD: Donor candidates undergo multiple psychosocial interviews early in the overall transplant evaluation process. Evaluators subsequently meet as a group, along with an independent ethicist, to determine psychosocial candidacy prior to final medical/surgical clearance. RESULTS: Between 2003 and 2007, 416 donor candidates initiated and/or underwent full evaluation, resulting in a 17.5% surgery and 55.5% exclusion rate among those individuals. Of those ruled out, 20.8% were for (medical or psychosocial) reasons associated with the recipient, and 8.7% were for donor-related psychosocial issues. CONCLUSION: Given the primacy ofpsychosocial and ethical issues in living liver donor candidate evaluation, the multiple interview process, followed by team discussion and overseen by an ethicist removed from other transplant program functions, has advantages as a donor assessment model.

Geographic variations in seed dispersal by ants: are plant and seed traits decisive?

The effect of local ant species on the dispersal success of a myrmecochorous plant, Helleborus foetidus, was analyzed in two populations of the Iberian Peninsula (Caurel and Cazorla, respectively). The contribution of the various local ant species to dispersal was very unequal. While 5 and 19 ant taxa visited the plants of Caurel and Cazorla, respectively, most removal activity (67 and 80%) was performed by two species only (Formica lugubris and Camponotus cruentatus, respectively). Visits by dispersers were also unequally distributed between neighboring plants. While some plants were always visited during the period of seed release, others were never visited. A regression model indicated that this pattern might be explained by two plant traits: ants preferred to visit plants that released more seeds and whose elaiosomes were richer in oleic acid. Although it has long been known that this compound triggers removal by ants, it is the first demonstration that quantitative variations in elaiosome traits contribute to variation in dispersal success. Finally, other variables being equal, morphological traits (seed size, elaiosome size, and elaiosome/seed size ratio) did not affect ant behavior. Although myrmecochory has long been considered a diffuse interaction, our results support the idea that, at local scale, a limited number of ant species may be decisive to its evolution.

Indirect effects of alternative food resources in an ant-plant interaction.

The seeds of many plant species present a food body that is consumed by animal dispersers. In theory, if the animals are polyphagous, the availability of alternative food resource other than the diaspore itself may influence its dispersal and survival. We used the myrmecochore Helleborus foetidus L. (Ranunculaceae), the seeds of which are attached to a lipid-rich elaiosome that is attractive to ants, as a model system to investigate (1) whether alternative foods that are present along with the plant affect ant foraging behavior and diaspore removal and (2) whether food availability in an ant nest affects seed predation and germination. In a field experiment, artificial diaspore depots were offered together with either sugar, insect corpses, seed, or no food (control). Contrary to the prediction that ants would rather concentrate their foraging effort on the highly rewarding alternative foods only, many workers, attracted by the sugar, switched to the hellebore diaspores, which significantly enhanced removal rate. Results obtained in the laboratory further indicated that the larvae of Aphaenogaster iberica (a major seed disperser) predated more on the H. foetidus embryos when no alternative food was available. This, in turn, slightly reduced seed germination. Overall, these results shed light, for the first time, on the potential indirect effects of alternative resources on the fate of diaspores adapted for ant dispersal.

Social isolation of mature workers affects nestmate recognition in the ant Camponotus fellah.

This study investigates the role of social stimulation on nestmate recognition in mature workers of Camponotus fellah. We isolated 4-week-old workers before examining their behaviour in dyadic reunion tests. At the age of 4 weeks, workers are normally intolerant towards both allospecific and homospecific but allocolonial individuals. However, when they were isolated for up to 20 days, allocolonial aggressions decreased while allospecific aggression remained constant. Workers isolated for 20 days also engaged in allocolonial trophallaxis. These results suggest that workers need to be reinforced by social stimulation during their adult life to keep precise nestmate recognition capacities. We discuss our data under the perspective of recent neuroethological data in social insects to propose a mechanism for the formation of the neural template used in the nestmate recognition process.

Camponotus fellah colony integration: worker individuality necessitates frequent hydrocarbon exchanges.

Our aim was to test the existence of Gestalt colony odour in Camponotus fellah. We isolated individual workers to prevent trophallaxis, allogrooming and body contact. After 20 days, the cuticular hydrocarbon profile of the isolated ants diverged from that of the parent colony. Moreover, each isolated individual had its own specific blend. This procedure showed that after about 20 days of isolation there was a turnover of the colony odour, revealing the genetically expressed hydrocarbon profile of each individual. It also showed that the cuticular hydrocarbon profile is polymorphic, and that its homogeneity within a colony is maintained by frequent exchanges of hydrocarbons between workers. Behavioural observations of resident workers, in their nest, towards nestmates reintroduced after isolation indicated that a short isolation period (3-5 days), which induced a minor change in hydrocarbon profile, provoked frequent trophallactic solicitations. These were likely to permit the isolated ants to readjust their hydrocarbon profile to that of the ants in the mother colony. Longer isolation periods (20-40 days) induced a greater change in hydrocarbon profile and made the residents intolerant towards their introduced nestmates. Therefore, our results clearly support the existence of a Gestalt colony odour in C. fellah. They also show that since individual hydrocarbon production is dynamic, workers are obliged to exchange hydrocarbons continually (mainly by trophallaxis) in order to be in the Gestalt, and properly integrate into the colony. Copyright 2000 The Association for the Study of Animal Behaviour.

Analysis of biogenic amines by solid-phase microextraction and high-performance liquid chromatography with electrochemical detection.

We investigated the new solid-phase microextraction method by high-performance liquid chromatography with electrochemical detection for the analysis of biogenic amines. The Carbowax-Templated Resin 50 microm (purple) fibre coating offers good performances for dopamine and serotonin separation, i.e., good selectivity and high sensibility (0.1 microg l(-1)). We also tested this fibre for biogenic amines quantification of rat striatum. The coating seems to be selective towards the amines and has low affinity for the metabolites, allowing a good separation and preventing drawbacks from the biological matrix. These first results obtained using this original separation method offer large perspectives of application to many biological samples.

Octopamine reverses the isolation-induced increase in trophallaxis in the carpenter ant Camponotus fellah.

Social deprivation is an unusual situation for ants that normally maintain continuous contact with their nestmates. When a worker was experimentally isolated for 5 days and then reunited with a nestmate, she engaged in prolonged trophallaxis. It is suggested that trophallaxis allows her to restore a social bond with her nestmates and to re-integrate into the colony, particularly via the exchange of colony-specific hydrocarbons. Octopamine reduced trophallaxis in these workers as well as hydrocarbon transfer between nestmates, but not hydrocarbon biosynthesis. Administration of serotonin to such 5-day-isolated ants had no effect on the percentage of trophallaxis. Administration of phentolamine alone, an octopamine antagonist, had no effect, but when co-administrated with octopamine it reduced the effect of octopamine alone and restored trophallaxis to control levels. Moreover, the observed effect of octopamine was not due to a non-specific effect on locomotor activity. Therefore, we hypothesise that octopamine mediates behaviour patterns linked to social bonding, such as trophallaxis. On the basis of an analogy with the role of norepinephrine in vertebrates, we suggest that the levels of octopamine in the brain of socially deprived ants may decrease, together with a concomitant increase in their urge to perform trophallaxis and to experience social contacts. Octopamine administration may reduce this social deprivation effect, and octopamine could therefore be regarded as being partly responsible for the social cohesion between nestmates in ant colonies.

Risk of venous access device wound complications in patients undergoing paclitaxel chemotherapy for gynecologic malignancies.

OBJECTIVE: To determine if wound complications after placement of a central venous catheter access device are related to the type of postsurgical cytotoxic chemotherapy administered. METHODS: All patients in a 10-year period undergoing placement of central venous access device followed by postsurgical chemotherapy for gynecologic malignancies were included in this retrospective case-control study. RESULTS: Sixty-eight patients underwent 78 placement procedures followed by chemotherapy. Six catheters (7.7%) in five patients developed wound complications. Variables evaluated included the type of gynecologic malignancy, previous use of chemotherapy, patient age and weight, preoperative white blood cell count, type of access device and insertion site, use of prophylactic antibiotics, type of chemotherapy and interval to administration, development of wound complication, and catheter removal. Univariate analysis shows an association between subsequent catheter site wound complication and paclitaxel use (P = 0.02) as well as wound complication and combined paclitaxel and cisplatin use (P = 0.005). Multivariate analysis with stepwise linear regression confirms that a paclitaxel containing regimen is associated with an increase in wound breakdown (P = 0.04). CONCLUSION: The use of a paclitaxel containing chemotherapeutic regimen administered after placement of an indwelling central venous access device in gynecologic oncology patients is associated with wound complications of the catheter site.

Ovarian cancer complicating pregnancy.

Ovarian cancer is the second most frequent gynecologic cancer complicating pregnancy. Although uncommon, this is a topic that encompasses multiple aspects of obstetrics and gynecology. The management of the adxenal mass in pregnancy, surgery for ovarian cancer, chemotherapy during gestation, and the use of tumor markers during pregnancy are discussed.

Thyroid evaluation of hospitalized psychiatric patients: the role of TSH screening for thyroid dysfunction.

The incidence and pattern of changes in thyroid function tests were studied in acutely hospitalized psychiatric patients and the cost effectiveness of a systematic screening program for thyroid dysfunction was estimated. Thyroid testing was performed on 1275 of 1424 (90%) admissions to the psychiatric wing of Strong Memorial Hospital between April 1, 1993 and March 30, 1994. Discharge samples were obtained in 232 patients who were hospitalized at least 2 days; 163 patients were admitted multiple times. Psychiatric diagnosis was coded using DSM-III-R criteria. TSH, T4, free T4, and T3 levels were measured within 48 h of admission. TSH values were most frequently abnormal (7.8%) and free T4 the least (1.3%). Admission and discharge thyroid tests were similar. Significant differences in the four parameters of thyroid function were present among the psychiatric groups. By analysis of variance every 1 microU/mL increase in TSH levels was associated with a 2.5% increase in length of stay (LOS) (95% confidence intervals: 0.21%, 4.75%), holding psychiatric diagnosis, age, and gender constant. For patients with elevated TSH levels, the average LOS was increased by 10.7 days (95% confidence intervals: 2.8, 18.7 days). It is concluded that patients hospitalized for psychiatric illness have an incidence of thyroid dysfunction at or slightly higher than the general population. However, patients with elevated TSH levels are hospitalized longer than those with normal or suppressed values.

Passive optical element with selective angular reflection.

This work is related to the development of passive selective transmission materials that will contribute to regularize the solar thermal gain. We propose an original solution to the problem of seasonal control of energetic input into buildings through windows. A passive optical element with selective angular reflection is used to solve this problem. This optical element allows sunlight to enter windows during the fall and winter, whereas, owing to the different astronomical path of the sun, it stops and rejects direct sunlight by means of the optical effect called total internal reflection (TIR) during the central spring-summer period. The purpose of this paper is to describe the optical element in some detail, to develop the principal design equations, and give the results of the optimization of optical and geometrical parameters.

Complex index of refraction of dental enamel at CO(2) laser wavelengths.

The reflectance vs angle of incidence method was used to determine the refractive index and absorption coefficient of dental enamel at CO(2) laser wavelengths. A strong wavelength dependence of the optical constants was observed in this spectral region which corresponds to a well-known absorption band of hydroxyapatite, the main constitutent of dental enamel. A directional dependence of the optical constants of dental enamel was also observed. The absorption coefficient reaches a maximum between 9.75 and 10 microm. This particularity may be important for the main CO(2) laser treatments proposed in dentistry up to now: surface treatment of teeth and fusion of dental materials.