Linear Discriminant Function Analysis Research Articles

Arginine vasotocin neuronal phenotypes, telencephalic fiber varicosities, and social behavior in butterflyfishes (Chaetodontidae): Potential similarities to birds and mammals

The neuropeptide arginine vasopressin (AVP) influences many social behaviors through its action in the forebrain of mammals. However, the function of the homologous arginine vasotocin (AVT) in the forebrain of fishes, specifically the telencephalon remains unresolved. We tested whether the density of AVT-immunoreactive (-ir) fiber varicosities, somata size or number of AVT-ir neuronal phenotypes within the forebrain were predictive of social behavior in reproductive males of seven species of butterflyfishes (family Chaetodontidae) in four phylogenetic clades. Similar to other fishes, the aggressive (often territorial) species in most cases had larger AVT-ir cells within the gigantocellular preoptic cell group. Linear discriminant function analyses demonstrated that the density of AVT-ir varicosities within homologous telencephalic nuclei to those important for social behavior in mammals and birds were predictive of aggressive behavior, social affiliations, and mating system. Of note, the density of AVT-ir varicosities within the ventral nucleus of the ventral telencephalon, thought to be homologous to the septum of other vertebrates, was the strongest predictor of aggressive behavior, social affiliation, and mating system. These results are consistent with the postulate that AVT within the telencephalon of fishes plays an important role in social behavior and may function in a similar manner to that of AVT / AVP in birds and mammals despite having cell populations solely within the preoptic area.

Distinguishing Wild from Hatchery‐Produced Juvenile Red Snapper with Otolith Chemical Signatures

AbstractOtolith chemical signatures were evaluated as natural tags to distinguish wild from hatchery‐produced juvenile red snapper Lutjanus campechanus. Otoliths were sampled from 59 hatchery‐reared fish and 146 wild fish collected over the continental shelf from northwest Florida to Texas. One sagitta from each fish was cleaned, dissolved in ultrapure nitric acid, and analyzed with sector field inductively coupled plasma mass spectrometry to test for differences in otolith element:Ca ratios (Ba:Ca, Li:Ca, Mg:Ca, Mn:Ca, and Sr:Ca) between wild and hatchery fish. The second sagitta was cleaned, ground to a fine powder, and analyzed with stable isotope ratio mass spectrometry to test for differences in delta (δ) values of the stable isotopes 13C and 18O. Significant differences existed in otolith chemical signatures between hatchery and wild juveniles (multivariate analysis of variance, Pillai's trace: P < 0.001). Jackknifed classification accuracies from linear discriminant function analysis indicated that hatchery fish could be distinguished from wild fish with 100% accuracy based on otolith chemical signatures. The most important otolith chemistry feature in distinguishing hatchery from wild fish was δ13C, with the mean difference in δ13C between hatchery and wild fish (−2.6‰) being similar to the mean difference in δ13C between hatchery feeds and the predominant food of wild juveniles (−2.8‰). Overall, results suggest that otolith chemical signatures may be employed as effective natural tags for mass marking of future stockings of red snapper or other marine fishes to estimate the hatchery contribution to wild populations.

Electronic-Nose Technology Using Sputum Samples in Diagnosis of Patients with Tuberculosis

We investigated the potential of two different electronic noses (EN; code named "Rob" and "Walter") to differentiate between sputum headspace samples from tuberculosis (TB) patients and non-TB patients. Only samples from Ziehl-Neelsen stain (ZN)- and Mycobacterium tuberculosis culture-positive (TBPOS) sputum samples and ZN- and culture-negative (TBNEG) samples were used for headspace analysis; with EN Rob, we used 284 samples from TB suspects (56 TBPOS and 228 TBNEG samples), and with EN Walter, we used 323 samples from TB suspects (80 TBPOS and 243 TBNEG samples). The best results were obtained using advanced data extraction and linear discriminant function analysis, resulting in a sensitivity of 68%, a specificity of 69%, and an accuracy of 69% for EN Rob; for EN Walter, the results were 75%, 67%, and 69%, respectively. Further research is still required to improve the sensitivity and specificity by choosing more selective sensors and type of sampling technique.

1H NMR spectroscopic studies on human seminal plasma: A probative discriminant function analysis classification model

Traditional seminal fluid-based clinical descriptors used to predict infertility and sub-fertility have shortcomings, including lack of insight into the underlying pathology. These methods are also time-consuming and labor-intensive. To address these limitations, 1H nuclear magnetic resonance (NMR) spectroscopy was used to identify and classify signature biomarkers. Semen samples collected from 60 healthy, fertile men and from 125 infertile (normozoospermic and oligozoospermic) patients. Lactate, alanine, choline, citrate, glycerophosphocholine (GPC), glutamine, tyrosine, histidine, phenylalanine, and uridine were measured by 1H NMR spectroscopy. The sperm concentration, motility, lipid peroxidation, and total protein were evaluated with standard laboratory methods in the same samples. NMR-quantified metabolites and clinical laboratory data were analyzed, separately, through linear multivariate discriminant function analysis (DFA) to determine the signature descriptors for each group. DFA reveals that alanine, citrate, GPC, tyrosine, and phenylalanine can be used to determine infertility. DFA-based classification demonstrated high accuracy (92.4% by NMR and 94.1% by clinical laboratory method) in differentiating healthy controls from infertile patients. This statistical analysis was also able to accurately classify normozoospermic to oligozoospermic samples (92.9% by NMR and 92.6% by clinical laboratory method). In conclusion, 1H NMR-based metabolic screening appears to be a promising, rapid, and non-invasive approach to probing infertility that has similar sensitivity and specificity to the tedious laboratory method.

Forensic diagnosis and classification of snakebite (neurotoxic and haemotoxic) from renal changes at autopsy: morphological and histological determinants using a semi-quantitative method

Mortality due to poisonous snakebite is an emerging public health concern. Of late, snakebite has drawn global attention. Snakebite is a well-known cause of renal pathology especially in the haemotoxic group. Deaths due to renal failure are very common in envenomation due to poisonous snakebite. In this investigation our aim was to devise autopsy-proven diagnostic criteria of snakebite from the renal changes to confirm and classify the type of snakebite in forensic casework. That would be of practical help to the forensic pathologist with access to limited resources. An arbitrary scoring system from histology was adopted for the present semi-quantitative analysis. The scoring system (with scores from 0 to 5) developed by the present study was effective, valid and was able to distinguish between snakebite and control. The score obtained at histology in cases of snakebite was significantly different from the control group (Mann-Whitney U = 71.5; P = 0.011). Using stepwise linear discriminant function (DF) analysis, the score (Mukhopadhyay's score [MS]) was seen to be the only predictor of the type of snakebite. This model (DF = 1.05 x MS-1.78) could correctly classify 93.3% of the cases into neurotoxic and haemotoxic variety of offending snake. This is an effective, cheap and easy semi-quantitative method of distinguishing neurotoxic and haematoxic snakes from the renal changes at autopsy. It would be useful for practical application in centres where sophisticated biochemical or immunological analyses are not available due to limited resources.

An epidemiological investigation in relative importance of factors associated with dental caries

Aim: To identify key discriminating factors associated with dental caries status by linear discriminant function analysis. A cross sectional study design was employed using clinical examination and questionnaire method. Dental caries examinations based on WHQ criteria and questionnaire method was performed on 500 subjects aged 14-40 years were selected randomly. These were separately classificd according to increasing individual DMFT scores and combined into positively and negatively health oriented group. A stepwise discriminant function analysis was used to identify the important discriminant factors associated with dental caries and also to segregate the subjects as those who were poor and good dental caries status. The subjects with low DMFT index scores reported that they brushed their teeth most frequently, they change their toothbrush within three months period, users of vertical & circular method of brushing and they rinse the mouth with water frequently. The subjects with high DMFT index scores reported who have frequent sweet consumption for longer duration, living in a larger family with higher income. The discriminant function analysis showed that 98.14% of subjects were found to be positively health oriented and corresponding percentage for the negatively health oriented towards dental caries (DMFT) was 93.47%. Frequent tooth brushing, vertical & circular methods of brushing and mouth ringing habit with water are important discriminant fuctory associated with lower dental caries. Duration of sweet consumption and frequency of sweet consumption are important discriminant factors associated with higher dental caries.

Assessment of English language learners: Using parent report on first language development

Purpose Obtaining information on both languages of English language learners for assessment can be a challenge in a multilingual context. It is often difficult or impossible to observe a child's first language directly due to the absence of resources available in every language spoken. The objectives of this study were (1) to develop a parent questionnaire on the first language development of English language learners that is not specific to a particular language/cultural group: the Alberta Language and Development Questionnaire (ALDeQ), and (2) to test how well scores on the ALDeQ differentiated between English language learners with typical development and those with language impairment. Method Participants were 139 typically developing children and 29 children with language impairment, aged 69 months with 18 months of exposure to English through preschool or school, on average. The ALDeQ consists of four sections: early milestones, current first language abilities, behaviour patterns and activity preferences, and family history. ALDeQ total scores are proportions calculated across all sections. Results t-test analyses revealed robust between-group differences for ALDeQ total scores, and for each section score, with medium to very large effect sizes. Linear discriminant function analysis showed the ALDeQ total scores to be a significant and moderate discriminator between the typically developing and language impaired group, but with better specificity than sensitivity. The early milestones section scores emerged as the strongest discriminator among the four section scores. Parent responses showed that both the typically developing and language-impaired groups included children experiencing first language loss, but nevertheless, the current first language abilities section was the second strongest between-group discriminator. Conclusion The ALDeQ would be useful to speech–language pathologists for obtaining information on English language learners’ first language development, in particular where the first language cannot be examined directly. The information provided by the ALDeQ could be used in conjunction with other measures in order to identify children with language impairment among English language learners. The complete ALDeQ and score interpretation information are given in Appendix A. Learning outcomes: Readers will (1) have a general understanding of how parent report could be useful for assessment in a multilingual context; (2) be aware of how first language loss in minority language children could impact assessment, and (3) have specific knowledge of a particular parent questionnaire and how it can be used to assist in identifying English language learners with language delay/impairment.

Assessment of otolith chemistry for identifying source environment of fishes in the lower Illinois River, Illinois

Knowledge of habitats used by fish throughout their life history is important for the management and conservation of riverine fish populations and habitats. Naturally occurring chemical markers in otoliths have recently been used to determine natal origins and environmental history of fishes in a variety of marine and freshwater environments. However, to our knowledge, no studies have examined the applicability of this technique in large floodplain rivers in the USA. We evaluated otolith microchemistry and stable isotopic composition as tools for determining origins of fishes in the lower Illinois River, its tributaries, and floodplain lakes. Fishes were collected from eight sites during summer 2006 and two additional sites in spring 2007. Water samples were obtained from these 10 sites plus one additional tributary during summer and fall 2006 and spring 2007. Otolith and water samples were analyzed for δ18O and a suite of trace elements; otoliths were also analyzed for δ13C. Tributaries, floodplain lakes, and the Illinois River possessed distinct isotopic and elemental signatures, principally driven by differences in δ18O and δ13C among floodplain lakes, the Illinois River, and tributary streams. Otoliths reflected the differences in water chemistry among habitats. Relationships between water and otolith δ18O and Sr:Ca were not significantly different among species, but some differences in relationships between water and otolith Ba:Ca among species were detected. Linear discriminant function analysis with a leave-one-out jackknife procedure on otolith δ18O and δ13C indicated that fish may be classified back to environment (Illinois River, tributary, or floodplain lake) of capture with 80–98% accuracy. Otolith microchemistry and stable isotope analyses provide a potentially effective means for determining recruitment sources and environmental history of fishes in the Illinois River. The ability to reconstruct environmental history of individual fish using naturally occurring isotopic markers in otoliths may also facilitate efforts to quantify nutrient and energy subsidies to the Illinois River provided by fishes that emigrate from floodplain lakes or tributaries.

Population connectivity of the Olympia oyster in southern California

The Olympia oyster is a useful model to study the population connectivity of estuarine invertebrates because it incorporates chemical information about the natal site into its shell before dispersal. This information can be accessed in recruits using laser ablation inductively coupled plasma mass spectrometry and compared with predispersal shells from possible source populations. Shelled Ostrea lurida larvae were periodically removed from adults at eight sites in four Southern California estuaries in the summers of 2006 and 2007. The ratios to calcium of copper, barium, lead, and uranium in the shells were used to distinguish among sites in linear discriminant function analyses. Jackknifed assignment accuracy by site was increased to 74% and 82% for 2006 and 2007, respectively, by grouping the eight sites into three regions. Settlement plates at each site in 2007 collected recent O. lurida recruits that were assigned to one of the three regions defined by the broods. San Diego Bay and the North County produced over 80% of the identifiable recruits in 2007, with Mission Bay producing the remaining minority. The majority of recruits to San Diego Bay were self‐recruits, whereas over half of the North County recruits were unidentifiable. Patterns of connectivity varied between recruitment pulses, but a substantial portion of larvae were exchanged among estuaries separated by as many as 75 km of coastline.

Differentiation of first-episode schizophrenia patients from healthy controls using ROI-based multiple structural brain variables

Brain morphometric measures from magnetic resonance imaging (MRI) have not been used to discriminate between first-episode patients with schizophrenia and healthy subjects. Magnetic resonance images were acquired from 34 (17 males, 17 females) first-episode schizophrenia patients and 48 (24 males, 24 females) age- and parental socio-economic status-matched healthy subjects. Twenty-nine regions of interest (ROI) were measured on 1-mm-thick coronal slices from the prefrontal and central parts of the brain. Linear discriminant function analysis was conducted using standardized z scores of the volumes of each ROI. Discriminant function analysis with cross-validation procedures revealed that brain anatomical variables correctly classified 75.6% of male subjects and 82.9% of female subjects, respectively. The results of the volumetric comparisons of each ROI between patients and controls were generally consistent with those of the previous literature. To our knowledge, this study provides the first evidence of MRI-based successful classification between first-episode patients with schizophrenia and healthy controls. The potential of these methods for early detection of schizophrenia should be further explored.

Modelling physico-chemical factors affecting occurrences of a non-indigenous planktonic copepod in northeast Pacific estuaries

Estuarine ecosystems along the Pacific coast of North America are vulnerable to invasions by non-indigenous planktonic copepods, with documented invasions by at least nine species introduced via ship’s ballast. One of these, the calanoid copepod Pseudodiaptomus inopinus, now occurs in a relatively wide geographical area in coastal estuaries of Washington and Oregon States. Although it appears to be well established in the region, plankton surveys conducted in 1992, 1996, 2000, and 2004 in estuaries from southern Vancouver Island in British Columbia, Canada, to northern California, United States indicate that it has not expanded its range. This static distribution suggests that P. inopinus has reached a distributional limit, and it may thus be a good organism for applying models for predicting planktonic invasions, by characterizing estuaries with and without populations of the copepod. In this study, we applied both parametric, linear (discriminant function analysis, logistic regression) and nonparametric, non-linear (classification trees) techniques to develop models for occurrence of P. inopinus, to identify parameters that may lead to successful invasions and to identify specific estuaries or regions that might be at risk of invasion by this species. Both model types had similar results, identifying relatively simple salinity- and stratification-based models as good predictors of P. inopinus. While different models selected slightly different sets of variables and thresholds, all models identified relatively low salinity and stratification of water column temperature and salinity as important predictors of P. inopinus presence. The models also identified several “false positives” that mainly occurred in more inland waters of Puget Sound—estuaries that did not have P. inopinus, but had the conditions that support it, and which may be at risk for future invasions by this species.

Actigraphy in the Assessment of Insomnia: A Quantitative Approach

The lack of quantitative criteria for identifying insomnia using actigraphy represents an unresolved limit for the use of actigraphy in a clinical setting. The current study was conducted to evaluate the most efficient actigraphic parameter in the assessment of insomnia and to suggest preliminary quantitative actigraphic criteria (QAC). Performing a retrospective study we recovered 408 actigraphic records from 3 sleep measure databases: 2 regarding insomnia patients (n = 126) and one normal sleepers (n = 282). We compared the 2 samples analyzing the following actigraphic sleep parameters: time in bed (TIB), sleep onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO), sleep efficiency percentage (SE%), number of awakenings longer than 5 minutes (NA > 5) and mean motor activity (MA). Moreover, a linear discriminant function (LDF) was developed to identify and combine the most useful actigraphic sleep parameters to separate insomnia patients from normal sleepers. Using Youden index we calculated the preliminary QAC for each actigraphic sleep parameter and for LDF. Receiver operator characteristic (ROC) curves for classifying the accuracy of QAC were performed. All sleep parameters recorded by actigraphy significantly differentiated the 2 groups, except TIB. An LDF analysis showed that the most useful combination of actigraphic sleep parameters to assess insomnia was TST, SOL, and NA > 5, which obtained the best ROC and the best balance between positive and negative predictive values compared to any single actigraphic parameter. Actigraphy provided a satisfactory objective measurement of sleep quality in insomnia patients. The combination of TST, SOL, and NA > 5 proved the best way to assess insomnia using actigraphy. Acknowledging that the lack of a technological standard and some methodological limitations prevent us generalizing our results, we recommend additional studies on larger populations using different actigraph models.

Historiography and forensic analysis of the Fort King George “skull”: Craniometric assessment using the specific population approach

In this article, we evaluate the association between the Fort King George "skull" and two Franciscans who were killed during a Guale revolt in 1597 and whose remains were never recovered (Pedro de Corpa and Francisco de Veráscola). The history and historiography of the revolt is summarized to generate a forensic profile for the individuals. The calvaria is described in terms of preservation, taphonomy, possible trauma, age, and sex. Because these factors are consistent with the individuals in question, population affinity is assessed using comparative craniometric analysis. In response to recent criticism of the typological nature of forensic population affinity assessment, we use a population specific approach, as advocated by Alice Brues (1992). Archaeological and historical data inform the occupation history of the site, and data from those specific populations are used in the comparative analysis. Results of linear discriminant function analysis indicate a low probability that the calvaria is a Guale (the precontact inhabitants of southeastern Georgia) or an individual of African descent. Comparison among European and Euro-American populations indicated poor discriminatory resolution; however, the closest match suggests a New World affinity rather than an Old World English, Scottish, or Iberian affinity for the specimen. Future analyses that will provide greater resolution about the identity of the calvaria are outlined. The case highlights the unique challenges of historical forensics cases relative to those of traditional jurisprudence, as well as the potential for using historiography to overcome those challenges in future analyses.

Hard tissue samples as markers of occupational exposure in a phosphate fertiliser plant

This paper describes the results of study on testing of hair and nails samples as possible markers of occupational exposure in a phosphate fertiliser plant. The key objectives were to verify if: (1) elements originating from fertiliser production may accumulate in hard tissue and hence allow preliminary occupational exposure risk assessment; (2) linear discriminant function analysis (LDA) may be applied as a diversification tool in preliminary assessment of occupational exposure risk based on hard tissue samples analysis; and (3) both hairs and nails can be used successfully as an efficient biological sample in biomonitoring studies and as markers of occupational exposure in various types of plant. The complex data matrix (2025 observations) obtained by the determination of 25 elements by neutron activation analysis in hard tissue samples was treated by LDA. The obtained results indicated the presence of two discriminant functions (DFs). The data variance explained by the first DF is 78%, and that by the second DF is 22%. The first DF is highly related to S, W, Cu, K and Mg concentrations and separates hair from nails samples, and the second DF, being related to phosphate fertiliser precursors, separates the control group from the employees. Sm, Al, Mo and As accumulate in nails and hairs of fertiliser plant employees, whereas Cl and Ti are removed from hard tissues. The mean concentrations of Na, In, I, Au, Dy, Ca, La, U, Sb, V, Zn, Mn and Co in hard tissue samples do not discriminate employees and control group members and hence prove their ineffectiveness in occupational exposure assessment in phosphate fertiliser plants.

Rapid discrimination of commercial strawberry cultivars using Fourier transform infrared spectroscopy data combined by multivariate analysis

To determine whether pattern recognition based on metabolite fingerprinting for whole cell extracts can be used to discriminate cultivars metabolically, leaves and fruits of five commercial strawberry cultivars were subjected to Fourier transform infrared (FT-IR) spectroscopy. FT-IR spectral data from leaves were analyzed by principal component analysis (PCA) and Fisher’s linear discriminant function analysis. The dendrogram based on hierarchical clustering analysis of these spectral data separated the five commercial cultivars into two major groups with originality. The first group consisted of Korean cultivars including ‘Maehyang’, ‘Seolhyang’, and ‘Gumhyang’, whereas in the second group, ‘Ryukbo’ clustered with ‘Janghee’, both Japanese cultivars. The results from analysis of fruits were the same as of leaves. We therefore conclude that the hierarchical dendrogram based on PCA of FT-IR data from leaves represents the most probable chemotaxonomical relationship between cultivars, enabling discrimination of cultivars in a rapid and simple manner.

Predicting Eurasian watermilfoil invasions in Minnesota

Eurasian watermilfoil is an invasive aquatic macrophyte that can be difficult to control once established in a lake. Identifying characteristics of lakes susceptible to Eurasian watermilfoil establishment can aid management by allowing managers to focus their education and monitoring efforts on susceptible lakes. Using linear discriminant function analysis and logistic regression to analyze known occurrences of Eurasian watermilfoil, we developed models to predict susceptible lakes in Minnesota. The most reliable predictors of Eurasian watermilfoil invasion were distance to the nearest invaded lake and duration of that invasion, indicating that transport (exposure) is an important variable. However, exposure is not a guarantee of establishment: lake size, alkalinity, Secchi depth, and lake depth were also significant predictors of invasion. Specifically, large deep lakes with moderate to high alkalinity and moderate Secchi depth were more likely to be invaded. Models predicted an additional 2,100 to more than 4,700 of Minnesota's more than 12,000 lakes could be invaded by Eurasian watermilfoil.

Blood fatty acids indicate inter- and intra-annual variation in the diet of Adélie penguins: Comparison with stomach content and stable isotope analysis

Adélie penguin ( Pygoscelis adeliae) diet is an important indicator of prevailing environmental conditions and resource availability. In this study, dietary variation within and between years was studied with fatty acid signature analysis (FASA), stomach content analysis (SCA) and stable isotope analysis (SIA). We profiled the fatty acid (FA) composition of whole blood collected from adult penguins throughout the breeding season, and from chicks during the crèche period, in 2001 and 2002. Differences were detected in FA profiles between years, breeding stage and age (adults vs. chicks). These patterns broadly corresponded to those observed from SCA and SIA, with a mix of krill and fish consumed in the early part of the breeding season in both years, krill dominating the diet during the chick-rearing periods in 2001, and fish in 2002. Different metabolic and physiological demands between stages, and ages, may also influence FA profiles but warrants further investigation. In-situ calibrations of adult FA blood profiles were made using corresponding stomach samples to quantify diet composition. Using linear discriminate function analysis, we classified adult FA profiles into 3 meal-types: krill, fish or mixed. A higher proportion of adults had fish-like profiles during the arrival and guard periods. Krill-like profiles dominated during the incubation and crèche periods, although there were a relatively high proportion of fish-like and mixed profiles as well. These patterns corresponded to results from SCA and SIA. This study demonstrates that FASA has the potential to be integrated with other dietary tools to enhance diet monitoring studies, which are currently integral to ecosystem management and conservation measures. The in-situ calibration method used offers a simple and effective alternative to more rigorous calibration techniques developed elsewhere.

A Comparison of the Glaucoma Probability Score to Earlier Heidelberg Retina Tomograph Data Analysis Tools in Classifying Normal and Glaucoma Patients

To compare the performance of the Glaucoma Probability Score (GPS), Mikelberg linear discriminant function (LDF), Burk LDF, and Moorfield regression analysis (MRA) in classifying optic disc images acquired from normals and glaucoma patients with the Heidelberg Retina Tomograph (HRT). This is a retrospective comparative study of 110 eyes of 110 subjects clinically categorized as glaucoma or normal. Topographic images of the optic nerve head were obtained from HRT. Data analysis of the HRT images were carried out using GPS, Mikelberg LDF, Burk LDF, and MRA. Diagnostic performances and agreement in classification between the data analysis tools were calculated and compared for GPS, Mikelberg LDF, Burk LDF, and MRA. The highest specificity but lowest sensitivity value was obtained using the Burk LDF. The highest sensitivity but lowest specificity was obtained using the GPS. The GPS and MRA were however similar in performance. Sensitivity and specificity values of the GPS and other LDFs were affected by disc size. The GPS compared similarly with the MRA without the need of additional contour line placements. Disc size is still an important factor in classification by the GPS and the other LDFs.

Pharmacotherapy of Schizophrenic Patients: Preponderance of Off-Label Drug Use

Multiple drug class combinations are often prescribed for the treatment of schizophrenia, although antipsychotic monotherapy reflects FDA labeling and scientific justification for combinations is highly variable. This study was performed to gain current data regarding drug treatment of schizophrenia as practiced in the community and to assess the frequencies of off-label drug class combinations. 200 DSM IV-diagnosed schizophrenic patients recruited from community treatment sources participated in this cross-sectional study of community based schizophrenic patients. Drug class categories include First and Second Generation Antipsychotic drugs (FGA and SGA, respectively), mood stabilizers, antidepressants and anti-anxiety drugs. 25.5% of patients received antipsychotic monotherapy; 70% of patients received an antipsychotic and another drug class. A total of 42.5% of patients received more than one antipsychotic drug. The most common drug class combination was antipsychotic and a mood stabilizer. Stepwise linear discriminant function analysis identified the diagnosis of schizoaffective schizophrenia, history of having physically hurt someone and high scores on the General Portion of the PANSS rating scale predicted the combined use of an antipsychotic drug and a mood stabilizer. “Real world” pharmacotherapy of schizophrenia has developed its own established practice that is predominantly off-label and may have outstripped current data support. The economic implications for public sector payers are substantial as well as for the revenue of the pharmaceutical industry, whose promotion of off-label drug use is an increasingly problematic. These data are consistent with the recognition of the therapeutic limitations of both first and second generation antipsychotic drugs.

Stable isotopes and fatty acid signatures reveal age- and stage-dependent foraging niches in tufted puffins

Major breeding failures of seabird populations are sometimes attributed to reduced egg laying or abandonment of incubation due to nutritional stress, yet diets during these reproductive stages are often poorly characterized. We used stable isotopes and fatty acid (FA) signatures to infer age- (adult vs. nestling) and stage-dependent foraging niches of tufted puffins Fratercula cirrhata captured in Chiniak Bay, Kodiak Island, Alaska, USA, from 2003 to 2005. Whole blood δ 15 N values indicated a seasonal shift in trophic niche of adults: 15 N enrichment was consistent with a 0.47 to 0.68 increase in trophic level of feeding from pre-lay to late chick-rearing. Although incomplete turnover of blood cells from the pre-lay period likely contributed to intermediate δ 15 N values of incubating puffins, this was insufficient to account for differences between incubating and chick-rearing adults. Differences in δ 15 N and δ 13 C between chick-rearing adults and nestlings were small and inconsistent between years. Discriminant function analysis (DFA) using the 14 most abundant FAs classified indi- viduals by reproductive stage and age within each year with a high level of accuracy (linear DFA: 93 to 99%; quadratic DFA: 80 to 92%). When all years were combined, accuracy of cross-validated clas- sification remained high (linear DFA: 90%; quadratic DFA: 76%). Based on stable isotopes and FA signatures, we conclude that foraging niches are stage-dependent in this species and suggest that chick-rearing adults do not typically feed at a lower trophic level than nestlings but likely consume a different array of prey species.