bluuebunny/crossref_metadata_2025 huggingface dataset:
Wirksamkeit und Wirkungen der Arbeitgeberkündigung: Was erfasst die Ausschlussfrist des § 4 KSchG?
Authors: Nord Jantina , Linnert-Epple Julie
Published: March 2010

Der Beitrag verdeutlicht, dass die Arbeitgeberkündigung ein einseitiges Rechtsgeschäft darstellt. Die Kündigungserklärung bildet lediglich den Tatbestand dieses Rechtsgeschäfts. Auf der Ebene ihrer Wirksamkeit als Rechtsgeschäft ist die Kündigung von bestimmten Voraussetzungen abhängig, damit sie dass Arbeitsverhältnis beenden kann. Nur solche Wirksamkeitsvoraussetzungen oder -hindernisse werden von der Präklusion nach §§ 4, 7 KSchG erfasst. Die Frage, zu welchem Zeitpunkt das Arbeitsverhältnis endet, betrifft die Kündigungswirkungen und muss nicht innerhalb der Frist des § 4 Satz 1 KSchG geltend gemacht werden. Unterschreitet der Arbeitgeber die zulässige Kündigungsfrist, so ergibt sich der Beendigungstermin des Arbeitsverhältnisses direkt aus der vertraglichen, tarifvertraglichen oder gesetzlichen Regelung und nicht mittels Auslegung der Kündigungserklärung. Eine Sonderstellung nimmt die von einem Nichtberechtigten unterzeichnete Kündigungserklärung ein, da seine Unterschrift dem Schriftformgebot nicht entspricht und § 4 Satz 1 KSchG den Beginn der 3-Wochen-Frist vom Zugang einer schriftlichen Kündigungserklärung abhängig macht.
Rechtfertigung vorsätzlicher Tötungen im Allgemeinen und speziell bei Sterbehilfe
Authors: Kühl Kristian
Published: March 2010

Die vorsätzliche Tötung eines anderen Menschen, die der Totschlag nach § 212 StGB in ihrer Grundform, d. h. ohne strafmildernde oder strafschärfende Zusätze, unter Strafe stellt, ist eines der schwersten Verbrechen, nicht nur im Strafgesetzbuch, sondern in allen Rechtsordnungen; auch in der Ethik/Moral wird sie als Sünde oder »Verbrechen« behandelt. Ihre Rechtswidrigkeit ergibt sich aus dem einseitigen Übergriff in die Freiheitssphäre des Opfers, das um sein Leben als Basis aller Freiheitsausübung gebracht wird. Ob und unter welchen Umständen gleichwohl die Rechtswidrigkeit einer Tötung entfallen kann, wird im Folgenden näher erörtert. Dabei soll nicht zuletzt auch die Rechtfertigung der Sterbehilfe genauer betrachtet werden, wobei auch die Patientenverfügung über das Sterbenlassen nach dem neuen Betreuungsrecht der §§ 1901 a ff. BGB besondere Berücksichtigung finden soll.
Der Gesellschaftsvertrag der Unternehmergesellschaft (haftungsbeschränkt)
Authors: Ramm Joachim
Published: March 2010

Der folgende Beitrag soll einmal die Entwicklung der Unternehmergesellschaft (haftungsbeschränkt) und deren wichtigsten Regelungen aufzeigen. Das herkömmliche Haftungssystem der GmbH wird durch die Unternehmergesellschaft verschoben. Fraglich ist insbesondere, ob die schnelle, einfache und billige Gründung der »Mini-GmbH« wirklich hält, was sie verspricht: um Notarkosten zu sparen, kann diese mit Hilfe eines »Musterprotokolls« gegründet werden. Der Beitrag geht der Frage nach, ob dies wirklich sinnvoll ist. Mit diesen aktuellen Fragestellungen sollte der Student der Wahlfachgruppe »Handels- und Gesellschaftsrecht« vertraut sein.
Calibration Standards for Biodiesel Fuels
Authors: Clampitt Bert H. , Sardisco John B.
Published: March 2010

There are over 60 ASTM and other regulatory standards regarding the manufacture and sales of biodiesel fuels. These international standards require a number of calibration standards for evaluation of a biodiesel fuel. Some of the biodiesel testing are the same as required for petroleum based diesel fuel; however a number of these tests are unique to the biodiesel industry. This paper lists all the known standard procedures that biodiesel fuels must be evaluated against. It lists all the procedures where no calibration standards are required, those procedures that require calibration standards that are more or less common to the diesel industry, and those procedures that require calibration standards that are unique to the biodiesel industry (e.g., ASTM D6584, “Free and Total Glycerine”).
Glycerol Tri-Ester Derivatives as Diluent to Improve Low Temperature Properties of Vegetable Oils
Authors: Shah Shailesh N. , Moser Bryan R. , Sharma Brajendra K.
Published: March 2010

The large-scale production of biodiesel has led to a surplus of glycerol, so the new commercial uses of this co-product are being sought. Twenty-three vegetable oils were screened using glycerol tris(2-ethylhexanoate) [GTEH] as a diluent to improve the low temperature properties. Epoxidized soybean oil (ESBO) and palm oil (PO) have shown maximum improvements in pour points (PPs) upon addition of GTEH as diluent. Maximum improvements in PP of 16 and 9°C were observed in ESBO and PO, with 50 and 25 vol % GTEH, respectively. The five vegetable oils (ESBO, PO, sunflower oil (SFO), mid-oleic SFO, and camelina oil (CO)) with maximum improvement in PP were studied further at lower concentrations of GTEH. The variation in PP response to GTEH is attributed to variations in the fatty acid compositions of the vegetable oils. This study demonstrates the viability of using GTEH as diluents with vegetable oils to improve their low temperature properties.
Direct effect of methylprednisolone on renal sodium and water transport via the principal cells in the kidney
Authors: Lauridsen Thomas G , Vase Henrik , Bech Jesper N , Nielsen Søren , Pedersen Erling B
Published: March 2010

Background

Glucocorticoids influence renal concentrating and diluting ability. We tested the hypothesis that methylprednisolone treatment increased renal water and sodium absorption by increased absorption via the aquaporin-2 (AQP2) water channels and the epithelial sodium channels (ENaCs) respectively.

Methods

The effect of methylprednisolone was measured during fasting in a randomized, placebo-controlled, single-blinded cross-over study of 15 healthy humans. The subjects received a standardized diet on day 1, fasted on day 2, and received 500 mg methylprednisolone intravenously on day 3. The effect variables were urinary excretions of AQP2 (u-AQP2), urinary excretion of the β-fraction of the ENaC (u-ENaCβ), cAMP (u-cAMP), prostaglandin E2(u-PGE2), free water clearance (), and fractional excretion of sodium (FENa), and plasma vasopressin (p-AVP), angiotensin II (p-Ang II), aldosterone (p-Aldo), atrial natriuretic peptide (p-ANP), and brain natriuretic peptide (p-BNP).

Results

Methylprednisolone treatment increased u-AQP2, u-ENaCβ, and p-AVP significantly, but did not change u-cAMP,, and FENa. P-ANP increased during methylprednisolone treatment, but after the increase in u-AQP2 and u-ENaCβ. U-PGE2, p-Ang II, and p-BNP were unchanged. Heart rate increased and diastolic blood pressure fell.

Conclusions

Methylprednisolone increased u-AQP2 and u-ENaC. Neither the AVP–cAMP axis nor changes in the renin–angiotensin–Aldo system, or the natriuretic peptide system seems to bear a causal relationship with the increase in either u-AQP2 or u-ENaC. Most probably, the effect is mediated via a direct effect of methylprednisolone on the principal cells. The lack of decrease in urinary output and sodium reabsorption most likely can be attributed to the diuretic and natriuretic properties of the increased secretion of ANP.
Parasitoids (Hymenoptera: Braconidae: Aphidiinae) Attacking Aphids Feeding on Solanaceae and Cucurbitaceae Crops in Southeastern Europe: Aphidiine-Aphid-Plant Associations and Key
Authors: Kavallieratos Nickolas G , Tomanović Željko , Starý Petr , Žikić Vladimir , Petrović-Obradović Olivera
Published: March 2010

Original information on aphidiine braconids attacking aphids feeding on Solanaceae (i.e., Capsicum annuum L., Lycium europaeum L., Lycopersicon esculentum Miller, Solanum spp.) and Cucurbitaceae (i.e., Citrullus vulgaris Schrad., Cucumis spp., Cucurbita pepo L.) plants in southeastern Europe is presented. A total of 13 species are keyed and illustrated with scanning electron micrographs, microscope micrographs and line drawings. The aphidiines presented in this work have been identified from nine aphid taxa. Two hundred four aphidiine-aphid-plant associations are presented, 176 of which are new. The results are discussed in relation to over-all parasitoid-aphid-plant associations in the area.
Across- and Within-Population Differences in the Size and Scaling Relationship of a Sexually Selected Trait in Leptoscelis tricolor(Hemiptera: Coreidae)
Authors: Miller Christine W , Emlen Douglas J
Published: March 2010

Sexually selected traits are often assumed to convey information to conspecifics about the condition and genetic quality of an individual. However, sexually selected traits also are hypothesized to be among the most rapidly evolving and phenotypically plastic traits in natural populations. When found, such variability can bring into question the reliability of these traits as sexually-selected signals. Here, we examine the expression of a male weapon over multiple spatial and temporal scales in the wild. Specifically, we measured the expression of enlarged hind femora across and within populations of the Neotropical bug Leptoscelis tricolor Westwood (Hemiptera: Coreidae). We found significant variation in the size of this trait across populations and even within a population according to the plant species where adult males were collected. We also found differences in the intercept of the scaling relationship with body size; for a given body size, males in some populations express larger sexually selected traits than males in other populations. These results support the hypothesis that the expression of sexually selected traits is dynamic over space and perhaps time. Such patterns suggest that environmental variation or small amounts of movement across genetically differentiated populations may confound the reliability of information contained in the expression of these traits.
The Fall Armyworm Triose Phosphate Isomerase (Tpi) Gene as a Marker of Strain Identity and Interstrain Mating
Authors: Nagoshi Rodney N
Published: March 2010

Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a significant agricultural pest in the United States, affecting most notably sweet corn, Zea mays L., and turfgrass. Two strains exist that differ physiologically and behaviorally but are morphologically indistinguishable. Polymorphisms within the fall armyworm Triose phosphate isomerase gene (Tpi; EC 5.3.1.1) were characterized and used to develop a polymerase chain reaction-based method for discriminating fall armyworm strains. The Tpi markers were used in multilocus analysis to estimate interstrain hybrid frequency and their distribution in populations from the United States and Brazil. The results were compared with previous studies using different marker combinations to test hypotheses about interstrain mating behavior and to explain earlier observations of unusual strain distribution patterns. The importance of understanding the frequency and consequences of interstrain hybridization to deciphering the mechanism of strain divergence and the distribution of fall armyworm subpopulations in different habitats are discussed.
Biology of the Adult Stage ofUfens principalis(Hymenoptera: Trichogrammatidae), an Egg Parasitoid ofHomalodiscaspp.(Hemiptera: Cicadellidae) in Southern California
Authors: Al-Wahaibi Ali K , Morse Joseph G
Published: March 2010

Aspects of the biology of the adult stage of Ufens principalis Owen (Hymenoptera: Trichogrammatidae), an important parasitoid of Homalodisca (Hemiptera: Cicadellidae) eggs in southern California, were studied. The field-based sex ratio of U. principalis was significantly different from 1:1 and was female biased (62% females). Females and males did not differ significantly in size based on measurements of head width and hind tibia length, and these two variables were highly correlated. There was a significant effect of female age on egg load. Females aged 1, 4, and 5 d had significantly higher egg loads than freshly emerged females. There was also a significant positive linear relationship between egg load and hind tibia length. Egg load averaged 37.9 ± 1.1 eggs. Eggs, which measured 207.8 ± 12.2 µm in length, were elliptical with an anterior nipple-shaped constriction. The longevity of adults was significantly affected by temperature and food (1:1, honey/water). Food had a greater effect in prolonging life as temperature decreased from 35.0 to 10.0°C. The most long-lived adults were fed on honey and kept at 10.0°C (20.2 ± 3.3 d). The rate of parasitism was significantly affected by host age, being significantly higher for 0-h-old eggs than for 12-24-h-old host eggs. There was no significant difference in parasitism between 0-h- and 0-6-h-old eggs and between 0–6 and 12-24-h-old eggs.
Effects of Parasitization and Envenomation by the Endoparasitic Wasp Pimpla turionellae (Hymenoptera: Ichneumonidae) on Hemocyte Numbers, Morphology, and Viability of Its Host Galleria mellonella Lepidoptera: Pyralidae)
Authors: Er Aylin , Uçkan Fevzi , Rivers David B , Ergin Ekrem , Sak Olga
Published: March 2010

Venom from the pupal endoparasitoid Pimpla turionellae L. (Hymenoptera: Ichneumonidae) contains a mixture of biologically active components, which display potent paralytic, cytotoxic, and cytolytic effects toward hosts. Here, we further investigate whether parasitism or envenomation by P. turionellae alters hemocyte numbers of its host Galleria mellonella L. (Lepidoptera: Pyralidae). Total hemocyte counts declined sharply in pupae and larvae of G. mellonella exposed to P. turionellae. These same cellular responses occurred when wasp venom was artificially injected into hosts, suggesting that venom alone induces cytotoxicity in hemocytes. Analysis of the differential hemocyte counts in untreated pupae and larvae revealed that more than half of the circulating hemocytes were granular cells followed by plasmatocytes. Parasitism reduced the number of granular cells while increasing the number of plasmatocytes. This trend was most evident at 4 h postparasitism, and a similar trend was observed with the artificial injection of high (but not low) doses of venom. When isolated larval hemocytes were exposed to a LC99 dose of venom, a differential response was observed for granular cells versus plasmatocytes. Both types of cells displayed some formation of vacuoles within the cytoplasm within 15 min posttreatment. However, the degree of vacuole formation was much more extensive in granular cells at later time points than for plasmatocytes, and granular cells seemed much more susceptible to venom as evidenced by cell death.
Phytoseiid Mite Species from Croatia, with Description of a New Species of the Genus Typhlodromus (Typhlodromus)
Authors: Tixier M-S , Klaric V , Kreiter S , Duso C
Published: March 2010

This study reports the results of a survey carried out in the Ucka Nature Park in the northeastern part of Croatia. It reports for the first time a list of species belonging to the family Phytoseiidae from Croatia, as until now, only one species was known from this country. Seventeen species are reported, one of them being new to science. This species belongs to the genus Typhlodromus subgenus Typhlodromus in the subfamily Typhlodrominae: Typhlodromus (Typhlodromus) octogenipilus.
Quality Testing of Three Species of Tephritid Fruit Flies After Embryo Cryopreservation
Authors: Leopold Roger A , Rajamohan Arun , Shelly Todd E , Handler Alfred M
Published: March 2010

This study evaluates characteristics commonly used to define insect quality or fitness by using a complement of three species of tephritid fruit flies (Diptera: Tephritidae) obtained from cryopreserved embryos. Anastrepha ludens (Loew), Anastrepha suspensa (Loew), and Ceratitis capitata (Wiedemann) were used to assess embryo to adult emergence and adult longevity, flight ability, mating ability, fecundity, and genetic variability after cryopreservation. With the three species tested, embryo survival was reduced by 50–70% whereas adult eclosion seemed unaffected by cryogenic treatment. Laboratory cage survival of cryopreserved A. ludens paralleled that of controls when tested with or without food and water posttreatment. With C. capitata, field cage survival was also similar when the adult progeny of cryopreserved parents was compared with that of untreated flies of the same age. Assessment of flight ability of cryopreserved A. ludens over a 19-d period by using a flight mill showed no statistical difference when compared with the untreated groups over the same time period. Flight ability within field cages for newly emerged progeny of cryopreserved C. capitata also mirrored that of the controls. Observed matings occurring within laboratory cages containing equal numbers of A. ludens males and females did not differ from comparable control groups. Furthermore, male progeny obtained from cryopreserved C. capitata parents competed equally with untreated males for mates while housed in field cages. A laboratory analysis of fertility and fecundity of A. suspensa revealed that males mated with control females were unaffected by cryopreservation as embryos, whereas cryopreserved females exhibited a significantly reduced fecundity when mated with control males. The fecundity of C. capitata progeny of cryopreserved parents also did not differ from control levels while caged under laboratory conditions. A random amplified polymorphic DNA assay of the genetic diversity of A. ludens comparing cryopreserved males with control males showed that the coefficient of similarity was ≥85%. This study indicates that embryo cryopreservation had little or no effect on the reproduction, longevity and flight of the species tested and can be used to support maintenance of insect stocks and control programs supported by the mass-rearing process.
Spatiotemporal Variation in Cicada Diversity and Distribution, and Tree Use by Exuviating Nymphs, in East Asian Tropical Reef-Karst Forests and Forestry Plantations
Authors: Lee Ya-Fu , Lin Yu-Hsiu , Wu Shu-Hui
Published: March 2010

Spatiotemporal variation in the species composition, relative abundance, and plant use by cicada nymphs were studied among continuous and fragmented forests and human-modified forestry plantations upon an uplifted reef-karst substrate in tropical East Asia. Nymphal emergence was concentrated in the rainy season but tended to begin earlier, end later, or both, on plantations. Species abundances fluctuated over time and among the types of forests, with greater variation in plantations and fragmented forests. Seven cicada species were present, but the overall similarity in species composition was low among the forest types. Higher mean numbers of species and mean abundances occurred on plantations than in fragmented and continuous forests, but the species heterogeneity was higher in continuous forests and lowest on plantations. Exuviae were found at various heights that were correlated positively with the abundance of exuviae and negatively with the diameter at breast height of trees, whereas coefficients of variation in the height distribution among trees were not correlated with the abundance of exuviae. The plant-use breadth was widest in the cicadas Chremistica ochracea (Walker) and narrowest in Cryptotympana takasagona. Kato, Phtypleura takasagona Matsumura, and Euterpnosia koshunensis Kato, with the other species intermediate, corresponding with their relative abundance. Among-species overlap was generally higher in the continuous forests but declined in forest fragments and plantations. Our results indicated that fragmenting tropical primary forests and creating plantations may generate higher richness and abundance of annual cicadas, but risk the loss of rare or endemic species that show a greater preference for tree species of the primary forests.
Three Remarkable New Fungus-Growing Ant Species of the GenusMyrmicocrypta(Hymenoptera: Formicidae), with a Reassessment of the Characters That Define the Genus and Its Position within the Attini
Authors: Sosa-Calvo J , Schultz T R
Published: March 2010

Three new species of the fungus-growing ant genus Myrmicocrypta Fr. Smith are described from Brazil and Peru, all unique within the genus due to their shared character state of erect pilosity. Myrmicocrypta erectapilosa sp. nov. and Myrmicocrypta bucki sp. nov. are otherwise typical for the genus in their small size and effaced, tuberculate sculpture, whereas Myrmicocrypta camargoi sp. nov. is also unique in its large size and pronounced sculpture. M. erectapilosa and M. bucki are closely related but can be distinguished by differences in the frontoclypeal and hypostomal teeth, frontal lobes, mesonotal sculpture, and propodeal spines. All castes (workers, gynes, and males) are described for M. camargoi, workers and gynes are described for M. erectapilosa, and only workers are described for M. bucki. Because the erect pilosity encountered in these species contradicts the state previously considered diagnostic for the genus, that of appressed, spatulate or squamiform pilosity found in all other Myrmicocrypta species, we necessarily discuss the characters that define the genus Myrmicocrypta and review its phylogenetic position within the tribe Attini.
Stage-Specific Defensive Strategies of Three Mantid Species, Tenodera aridifolia, Hierodura patellifera, and Statilia maculata, Against a Natural Enemy, Takydromus tachydromoides
Authors: Watanabe H , Yano E
Published: March 2010

Three mantid species, Tenodera aridifolia (Stoll), Hierodura patellifera (Serville), and Statilia maculata Thunberg, of varying body size and habitats, exhibited defensive reactions when faced with a natural enemy, the Japanese skink, Takydromus tachydromoides (Schlegel). Defensive reactions were analyzed as primary or secondary defenses for all stages. Of the primary defenses, the cryptic reaction was the main defensive reaction: mantids lowered the prothorax and simultaneously stretched the prothoracic legs, the antennae were arranged forward, and the abdomen was sometimes extended posteriorly. The frequency of the subcryptic reaction as a primary defense tended to increase with more advanced developmental stage. The primary defensive strategy switched at specific developmental stage and also depended on the distance between the prey mantid and the natural enemy. In some instars, T. aridifolia and H. patellifera displayed the cryptic reaction when the mantid—foe distance was long, whereas they displayed the subcryptic reaction when the mantid—foe distance was short. However, S. maculata did not switch defense strategies based on the mantid—foe distance. The secondary defenses of young instar nymphs of T. aridifolia and H. patellifera were primarily defensive reactions, whereas the frequency of aggressive reactions tended to increase with developmental stage. S. maculata did not display aggressive reactions during any stage. We concluded that the primary and secondary defenses used by mantids depend on the developmental stage and mantid—foe distance. Moreover, three mantid species that vary in both body size and habitat showed different defensive reactions when faced with a natural enemy.
Biology of the Armored ScaleRhizaspidiotus donacis(Hemiptera: Diaspididae), a Candidate Agent for Biological Control of Giant Reed
Authors: Moran Patrick J , Goolsby John A
Published: March 2010

The development, survival, and reproductive output of the armored scale Rhizaspidiotus donacis Leonardi (Hemiptera: Diaspididae) were determined as part of an evaluation of this scale for biological control of giant reed, Arundo donax L. Scale crawlers produced by females collected in southern France and Spain lived for less than two d in the absence of a host. On A. donax shoots held under a diurnally variable temperature regime (15–26°C), crawlers settled on leaf collars and axillary stem bases and completed the first instar within 14 d. Winged adult males emerged within six wk and lived 1.7 d in vials. Immobile adult females were observed 75 d after crawler release. Development time to adult was reduced 15% in males and 28% in females when scales were reared at a constant temperature of 26°C. Survival from crawler to adult was 20–25%. The generation time for laboratoryreared females was 170d and their average life span was 203 d. Females from field collections produced an average of 85 live crawlers, 2.7-fold more than did colony-reared females. Across 31 field collections, female size was correlated to the percentage of scales that were reproductive. However, among eight collections from two Spanish sites, size varied but was not correlated to reproductive success. Peak reproduction from field collections occurred between November and March, and the scale completed two generations per year. Biological information about R. donacis will aid production, release, and field evaluation of this scale for biological control of invasive A. donax in North America.
Reproductive Refractoriness in the Western Tarnished Plant Bug (Hemiptera: Miridae)
Authors: Brent C S
Published: March 2010

Adult Lygus hesperus Knight (Hemiptera: Miridae), major crop pests of the south-western United States, can mate repeatedly during their lives, potentially enhancing the lifetime fitness of both sexes. However, the periodicity of mating and its regulation in this species is poorly understood. In this study the postmating refractory period for both sexes is described. Males were found to have a median delay of 24 h, which seems to be the minimum time needed to refill the accessory glands and produce another viably sized spermatophore. The median refractory period in mated females was 5 d, but sometimes lasted longer than 2 wk. The loss of sexual receptivity in mated females, at least for the first 24 h, seems to be induced by males; spermatophore homogenates injected directly into the abdomen of virgin females reduced their sexual receptivity. The total duration of female refractoriness may be dictated by the starting size of a spermatophore and the rate at which it degrades.
Honey Bees (Hymenoptera: Apidae) with the Trait of Varroa Sensitive Hygiene Remove Brood with All Reproductive Stages of Varroa Mites (Mesostigmata: Varroidae)
Authors: Harris Jeffrey W , Danka Robert G , Villa José D
Published: March 2010

Varroa sensitive hygiene (VSH) is a trait of honey bees, Apis mellifera L. (Hymenoptera: Apidae), which supports resistance to Varroa destructor Anderson & Trueman. VSH is the hygienic removal of mite-infested pupa. Bees selectively bred for VSH produce colonies in which the fertility of mites decreases over time. In addition, mite fertility decreases after infested brood is exposed to VSH bees for 1 wk. The purpose of this study was to decide whether the reduction in mite fertility is caused by selective removal of mites that produce offspring. Initially, we monitored changes in a small patch of capped brood during exposure to VSH bees at 2-h intervals through 60 h, which provided a reference for the subsequent experiment. The first test showed that VSH bees uncapped, recapped, and began to remove many pupae in ≈2 h. The approach in the second experiment was to compare the percentage of fertile mites from brood exposed to VSH bees for a 3-h period to the percentage of fertile mites in brood that was protected from hygiene by a screen. There were no significant differences in fertility between mites on pupae that were being removed by the bees and mites on protected pupae. These results suggest that neither egg-laying by foundress mites nor mite offspring are the stimuli that trigger hygienic removal of mite-infested pupae by VSH bees. It may be that hygienic activities such as the uncapping of brood cells inhibits or disrupts reproduction by varroa mites.
Chemoradiation in Pancreatic Adenocarcinoma: A Literature Review
Authors: Roy Rajarshi , Maraveyas Anthony
Published: March 2010

Adenocarcinoma of the exocrine pancreas has an annual incidence of 7,400 cases in the U.K. In comparison with other common cancers of solid organs, namely, breast, colorectal, and prostate cancer, pancreatic cancer has a high morbidity and mortality. Radical resection is possible in only 15%–20% of patients, and only 3%–4% of all patients presenting with this condition achieve long-term control and cure. Various strategies in the form of neoadjuvant and adjuvant treatment have been employed over the years to improve outcome, with limited success. Systemic chemotherapy remains the gold standard in the metastatic setting in good performance status patients, and adjuvant chemotherapy after resection of localized and locally advanced cancer has been found to improve outcome. The role of radiotherapy, however, remains controversial and is an area that merits further investigation in well-conducted multicenter trials at various stages of the disease in combination with systemic agents and exploiting recent advances in the delivery of radiotherapy. In this article, we review the published literature on the use of chemoradiation as a modality in various stages of pancreatic adenocarcinoma and highlight areas that future trials in this field should target for a way forward in this malignancy.
Predicting Response to Treatment in Gastroesophageal Junction Adenocarcinomas: Combining Clinical, Imaging, and Molecular Biomarkers
Authors: Bain Gillian H. , Petty Russell D.
Published: March 2010

Learning Objectives

After completing this course, the reader will be able to: Contrast the subtypes of gastroesophageal adenocarcinoma in order to select optimal therapeutic approaches for given subtypes.Compare the various tools (CT, MRI, PET, PET-CT, etc.) for evaluating response to therapy in order to determine whether to initiate new therapy.Evaluate response to neoadjuvant therapy, utilizing imaging, histopathogy of resected specimens, and biomarkers, to plan postoperative treatment.

This article is available for continuing medical education credit at CME.TheOncologist.com

The incidence of adenocarcinomas of the gastroesophageal junction (GEJ) is rapidly rising, and even in early-stage locoregional confined disease the 5-year survival rate rarely exceeds 25%–35%. Randomized trials and meta-analyses have demonstrated a benefit with neoadjuvant or perioperative chemotherapy and with neoadjuvant chemoradiotherapy. However, the optimal approach in individual patients is not clear and remains controversial. A consistent finding is that patients who have a histopathological response to neoadjuvant therapy are more likely to receive a survival benefit. These clinical data provide a strong argument for the urgent development of methods to predict histopathological response to neoadjuvant therapies for GEJ adenocarcinoma. Published data demonstrate that clinicopathological features (tumor location), imaging (fluorodeoxyglucose-positron emission tomography “metabolic response”), and tissue/molecular biomarkers may all have a predictive value for neoadjuvant therapies. However, it is uncertain from published data whether or not they will be useful for clinical decision making in individual patients. Existing candidate biomarkers need to be properly qualified and validated and novel biomarkers are required; and an optimal approach should involve the combination and integration of clinical, imaging, and molecular biomarkers. This review presents the evidence base and discusses novel experimental approaches for the combination of biomarker modalities to allow optimization of an individualized treatment approach in GEJ adenocarcinoma patients that may be relevant to other tumor types as well.
Continuous Sunitinib Treatment in Patients with Advanced Hepatocellular Carcinoma: A Swiss Group for Clinical Cancer Research (SAKK) and Swiss Association for the Study of the Liver (SASL) Multicenter Phase II Trial (SAKK 77/06)
Authors: Koeberle Dieter , Montemurro Michael , Samaras Panagiotis , Majno Pietro , Simcock Mathew , Limacher Andreas , Lerch Stefanie , Kovàcs Katalin , Inauen Roman , Hess Vivianne , Saletti Piercarlo , Borner Markus , Roth Arnaud , Bodoky György
Published: March 2010

Background.

Sunitinib (SU) is a multitargeted tyrosine kinase inhibitor with antitumor and antiangiogenic activity. The objective of this trial was to demonstrate antitumor activity of continuous SU treatment in patients with hepatocellular carcinoma (HCC).

Patients and Methods.

Key eligibility criteria included unresectable or metastatic HCC, no prior systemic anticancer treatment, measurable disease, and Child-Pugh class A or mild Child-Pugh class B liver dysfunction. Patients received 37.5 mg SU daily until progression or unacceptable toxicity. The primary endpoint was progression-free survival at 12 weeks (PFS12).

Results.

Forty-five patients were enrolled. The median age was 63 years; 89% had Child-Pugh class A disease and 47% had distant metastases. PFS12 was rated successful in 15 patients (33%; 95% confidence interval, 20%–47%). Over the whole trial period, one complete response and a 40% rate of stable disease as the best response were achieved. The median PFS duration, disease stabilization duration, time to progression, and overall survival time were 1.5, 2.9, 1.5, and 9.3 months, respectively. Grade 3 and 4 adverse events were infrequent. None of the 33 deaths were considered drug related.

Conclusion.

Continuous SU treatment with 37.5 mg daily is feasible and has moderate activity in patients with advanced HCC and mild to moderately impaired liver dysfunction. Under this trial design (>13 PFS12 successes), the therapy is considered promising. This is the first trial describing the clinical effects of continuous dosing of SU in HCC patients on a schedule that is used in an ongoing, randomized, phase III trial in comparison with the current treatment standard, sorafenib (ClinicalTrials.gov identifier, NCT00699374).
Replicated sampling increases efficiency in monitoring biological populations
Authors: Dennis Brian , Ponciano José Miguel , Taper Mark L.
Published: March 2010

Observation or sampling error in population monitoring can cause serious degradation of the inferences, such as estimates of trend or risk, that ecologists and managers frequently seek to make with time‐series observations of population abundances. We show that replicating the sampling process can considerably improve the information obtained from population monitoring. At each sampling time the sampling method would be repeated, either simultaneously or within a short time. In this study we examine the potential value of replicated sampling to population monitoring using a density‐dependent population model. We modify an existing population time‐series model, the Gompertz state‐space model, to incorporate replicated sampling, and we develop maximum‐likelihood and restricted maximum‐likelihood estimates of model parameters. Depending on sampling protocols, replication may or may not entail substantial extra cost. Some sampling programs already have replicated samples, but the samples are aggregated or pooled into one estimate of population abundance; such practice of aggregating samples, according to our model, loses considerable information about model parameters. The gains from replicated sampling are realized in substantially improved statistical inferences about model parameters, especially inferences for sorting out the contributions of process noise and observation error to observed population variability.
Life history allometries and production of small fauna
Authors: Reiss Julia , Schmid-Araya Jenny M.
Published: March 2010

The production of heterotrophic biomass is an important aspect of overall ecosystem functioning. However, single‐celled organisms or microscopic metazoans are often ignored in studies of secondary production, despite being very abundant and possessing high mass‐specific population growth rates, relative to the more widely studied larger taxa.

Here, we focused on how life history parameters scale with body size of ciliates and meiofauna (body mass range from ∼0.001 to 90 mg C/individual) and integrated experimental and survey data to calculate secondary production of these groups. First, we derived a single allometric scaling relationship between the intrinsic rate of population increase and body mass in a laboratory experiment. We then used this relationship to calculate secondary production for over 260 of these small species in the field, using survey data from two contrasting streams; one of which was nutrient rich, the other nutrient poor.

Results from laboratory cultures showed that the scaling relationship between body mass and both daily intrinsic rate of population increase and generation time followed a power law. The relationship between body mass and annual secondary production was consistent in both streams, but the number of taxa was greater in the more productive site. Both ciliates and meiofauna had high rates of biomass production, with annual P/B ratios (production divided by biomass) for the whole assemblage exceeding 11 in both streams. We conclude that a large fraction of benthic production is overlooked when protozoans and microscopic metazoans are excluded from estimates of biomass turnover.
Consumptive and nonconsumptive effects of cannibalism in fluctuating age‐structured populations
Authors: Wissinger Scott A. , Whiteman Howard H. , Denoël Mathieu , Mumford Miranda L. , Aubee Catherine B.
Published: March 2010

Theory and empirical studies suggest that cannibalism in age‐structured populations can regulate recruitment depending on the intensity of intraspecific competition between cannibals and victims and the nature of the cannibalism window, i.e., which size classes interact as cannibals and victims. Here we report on a series of experiments that quantify that window for age‐structured populations of salamander larvae and paedomorphic adults. We determined body size limits on cannibalism in microcosms and then the consumptive and nonconsumptive (injuries, foraging and activity, diet, growth) effects on victims in mesocosms with seminatural levels of habitat complexity and alternative prey. We found that cannibalism by the largest size classes (paedomorphs and ≥age 3+ yr larvae) occurs mainly on young‐of‐the‐year (YOY) victims. Surviving YOY and other small larvae had increased injuries, reduced activity levels, and reduced growth rates in the presence of cannibals. Data on YOY survival in an experiment in which we manipulated the density of paedomorphs combined with historical data on the number of cannibals in natural populations indicate that dominant cohorts of paedomorphs can cause observed recruitment failures. Dietary data indicate that ontogenetic shifts in diet should preclude strong intraspecific competition between YOY and cannibals in this species. Thus our results are consistent with previous empirical and theoretical work that suggests that recruitment regulation by cannibalism is most likely when YOY are vulnerable to cannibalism but have low dietary overlap with cannibals. Understanding the role of cannibalism in regulating recruitment in salamander populations is timely, given the widespread occurrences of amphibian decline. Previous studies have focused on extrinsic (including anthropogenic) factors that affect amphibian population dynamics, whereas the data presented here combined with long‐term field observations suggest the potential for intrinsically driven population cycles.
Spatial self‐organized patterning in seagrasses along a depth gradient of an intertidal ecosystem
Authors: van der Heide Tjisse , Bouma Tjeerd J. , van Nes Egbert H. , van de Koppel Johan , Scheffer Marten , Roelofs Jan G. M. , van Katwijk Marieke M. , Smolders Alfons J. P.
Published: March 2010

The spatial structure of seagrass landscapes is typically ascribed to the direct influence of physical factors such as hydrodynamics, light, and sediment transport. We studied regularly interspaced banded patterns, formed by elongated patches of seagrass, in a small‐scale intertidal ecosystem. We investigated (1) whether the observed spatial patterns may arise from feedback interactions between seagrass and its abiotic environment and (2) whether changes in abiotic conditions may lead to predictable changes in these spatial patterns. Field measurements, experiments, and a spatially explicit computer model identified a “scale‐dependent feedback” (a mechanism for spatial self‐organization) as a possible cause for the banded patterns. Increased protection from uprooting by improved anchoring with increasing seagrass density caused a local positive feedback. Sediment erosion around seagrass shoots increased with distance through the seagrass bands, hence causing a long‐range negative feedback. Measurements across the depth gradient of the intertidal, together with model simulations, demonstrated that seagrass cover and mean patch size were predictably influenced by additional external stress caused by light limitation and desiccation. Thus, our study provides direct empirical evidence for a consistent response of spatial self‐organized patterns to changing abiotic conditions, suggesting a potential use for self‐organized spatial patterns as stress indicators in ecosystems.
Selection ratios on community aggregated traits estimate ecological filters imposed on species by sites
Authors: Lichti Nathanael I. , Murphy Michael T.
Published: March 2010

Variation in community structure is mediated by interactions between species traits and a site's environmental characteristics. Previously, data on community composition at sites has been employed to correlate trait and environmental variables (e.g., RLQ analysis) and to predict community‐level expression of quantitative traits (i.e., community aggregated traits). Here, we demonstrate that the selection ratio, a method originating in animal resource selection studies, can estimate the ecological filters that site conditions impose on species traits by combining observed community aggregated traits with null models of species availability. This flexible, nonparametric approach expresses the filter at each site as a probability density function for the selection of individuals possessing a given trait value. By doing so, it generalizes the community aggregated trait concept to include categorical as well as continuous traits and allows for both intraspecific variation in trait expression and differences in species availability among sites. The resulting site‐level filter functions can be related to environmental covariates by standard statistical approaches (e.g., regression). The method complements existing techniques for analyzing trait–environment interactions in community ecology.
Seasonal plankton–fish interactions: light regime, prey phenology, and herring foraging
Authors: Varpe Øystein , Fiksen Øyvind
Published: March 2010

When prey and predator are seasonal migrants, encounters depend on migration phenologies and environmental constraints on predation. Here we investigate the relative contribution of seasonality in irradiance and prey abundance in shaping the rapid seasonal body condition increase of a migrating predator searching visually for its prey: the Norwegian spring‐spawning herring, Clupea harengus, feeding on the copepod Calanus finmarchicus. Two main seasonal pulses of prey are available to herring: (1) the parent generation of C. finmarchicus, with peak abundance in March–April, which appear too early to cause the main increase in herring condition; and (2) the abundant offspring generation of C. finmarchicus, with peak abundance in June–July, too late to explain the main increase in body condition. However, a mechanistic model of ingestion rate, including both solar irradiance and prey abundance, predicted seasonal food intake in good accordance with observed herring body condition. This suggests that the seasonality in herring foraging and energy storage is closely linked to the return of longer days in spring, and less dependent on a match or mismatch with seasonal peaks in abundance of their zooplankton prey. Consequently, light related constraints on foraging may make visually searching predators at high latitudes resilient to changes and fluctuations in prey phenology and abundance, but vulnerable to changes in the light regime, such as water clarity.
Early life history transitions and recruitment of Picea mariana in thawed boreal permafrost peatlands
Authors: Camill Philip , Chihara Laura , Adams Brad , Andreassi Christian , Barry Ann , Kalim Sahir , Limmer Jacob , Mandell Mike , Rafert Greg
Published: March 2010

Black spruce (Picea mariana) is the most abundant tree species in the boreal biome, but little is known about how climate warming may change recruitment in peatlands, especially those affected by permafrost thaw. We used results from a seven‐year study in northern Manitoba, Canada, to address the following questions: (1) What is the relative importance of early life history transitions on P. mariana recruitment? (2) How are these transitions mediated by biological and environmental factors, including competition, facilitation, disease, herbivory, water table depth, and soil nutrients? (3) Do interactions among these factors create additional recruitment limitations beyond those imposed by environmental factors changing with climate warming, such as hydrology? Seed rain was measured over six years on forested permafrost plateaus and in neighboring collapse scar bogs. Seed germination and seedling survival and growth were measured over 4–5 years in collapse scars and assessed across a three‐level water table treatment. Survival and growth experiments examined additional combinations of above‐ and belowground vascular plant competition and fertilizer addition. Results showed that failure of germination and survival on growing moss surfaces and reduced survival of seedlings in wetter microsites were primary constraints. Seed influx was significantly lower in collapse scars but likely did not limit recruitment. Biological and environmental factors mediating these life history transitions also differed in relative importance, and interactions among them tended to amplify recruitment limitation. Seedling survival was most strongly controlled by fast‐growing mosses in wet microsites but also was influenced by apparent drowning in wet plots, herbivory, and loss of foliage caused by a fungal pathogen. Seedling growth was strongly controlled by water table depth, nutrient and competition levels, and fungal pathogens. Multiple, interacting factors will affect P. mariana establishment in boreal peatlands during climate warming. Generalizations about recruitment relying on few environmental gradients sensitive to climate change, such as water table, may therefore not fully capture the complexities of establishment.