Measuring the Significance of Diversification Gains

This article investigates whether investing in alternative investment media provides statistically significant increases in portfolio performance. Employing methodology introduced by Kandel and Stambaugh (1987) and Gibbons, Ross and Shanken (1989), we measure the statistical significance of diversification gains for portfolios containing real and financial domestic assets, as well as international debt and equity issues. The NCREIF real estate series is further examined using the Geltner (1993) adjustment to the risk measure. In the 1978B93 sample period, neither international assets nor unadjusted real estate ever result in statistically significant increases in portfolio performance. When the Geltner adjustment is made, the allocation to real estate is substantially reduced in the expanded portfolio and also fails to result in a statistically significant increase in portfolio performance. These results may help to resolve the paradox between current portfolio allocations to real estate in practice and those suggested in the literature.

Effect of Perch Height and Position on the Usage in Enriched Colony Housing Systems for Laying Hens

In order to determine the utility of different perches in enriched colony housing systems for laying hens, the use of perches and an effect of the type and location in the system was examined in this behavioral study. Laying hens of the line Lohmann Selected Leghorn were housed in four different enriched colony housing systems which differed particularly in the alignment and arrangement of the functional areas. For analysis, perches were grouped into three types: low, low underneath the drinking trough and high. To evaluate the use of the perch types, video recordings were taken for 48 hours during three observation periods. These recordings were analyzed hourly at daytime and twice at nighttime. Through scan sampling, the overall number of hens using the perches and the fraction of hens per meter on a specific perch type were assessed. At nighttime, an average 62% of the laying hens used the perches. On average, 24% of the laying hens used the perches at daytime, with no significant difference between the different systems. Low perches that were not installed underneath the drinking trough were less commonly used than high perches. However, the hens used low perches that were positioned underneath the drinking trough more than other perch types during the day. At nighttime, high perches were used frequently and, depending on the system, more than the low perches. It should be considered that the hens used the low perches underneath the drinking trough during the day not to rest but rather to have better access to the drinking trough. It can be recommended that a sufficient number of high perches should be offered, so that all hens have access to these obviously preferred perches. If perches are installed underneath the drinking trough, it should be considered if additional perch space should be offered

Effect of Perch Height and Position on the Usage in Enriched Colony Housing Systems for Laying Hens

In order to determine the utility of different perches in enriched colony housing systems for laying hens, the use of perches and an effect of the type and location in the system was examined in this behavioral study. Laying hens of the line Lohmann Selected Leghorn were housed in four different enriched colony housing systems which differed particularly in the alignment and arrangement of the functional areas. For analysis, perches were grouped into three types: low, low underneath the drinking trough and high. To evaluate the use of the perch types, video recordings were taken for 48 hours during three observation periods. These recordings were analyzed hourly at daytime and twice at nighttime. Through scan sampling, the overall number of hens using the perches and the fraction of hens per meter on a specific perch type were assessed. At nighttime, an average 62% of the laying hens used the perches. On average, 24% of the laying hens used the perches at daytime, with no significant difference between the different systems. Low perches that were not installed underneath the drinking trough were less commonly used than high perches. However, the hens used low perches that were positioned underneath the drinking trough more than other perch types during the day. At nighttime, high perches were used frequently and, depending on the system, more than the low perches. It should be considered that the hens used the low perches underneath the drinking trough during the day not to rest but rather to have better access to the drinking trough. It can be recommended that a sufficient number of high perches should be offered, so that all hens have access to these obviously preferred perches. If perches are installed underneath the drinking trough, it should be considered if additional perch space should be offered

Aggressive dominance can decrease behavioral complexity on subordinates through synchronization of locomotor activities

Social environments are known to influence behavior. Moreover, within small social groups, dominant/subordinate relationships frequently emerge. Dominants can display aggressive behaviors towards subordinates and sustain priority access to resources. Herein, Japanese quail (Coturnix japonica) were used, given that they establish hierarchies through frequent aggressive interactions. We apply a combination of different mathematical tools to provide a precise quantification of the effect of social environments and the consequence of dominance at an individual level on the temporal dynamics of behavior. Main results show that subordinates performed locomotion dynamics with stronger long-range positive correlations in comparison to birds that receive few or no aggressions from conspecifics (more random dynamics). Dominant birds and their subordinates also showed a high level of synchronization in the locomotor pattern, likely emerging from the lack of environmental opportunities to engage in independent behavior. Findings suggest that dominance can potentially modulate behavioral dynamics through synchronization of locomotor activities.publishedVersionAlcala, Rocio. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Caliva, Jorge Martín. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Caliva, Jorge Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Flesia, Ana Georgina. Facultad de Matemática, Astronomía, Física y Computación; Argentina.Flesia, Ana Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigación y Estudios de Matemática; Argentina.Marin, Raúl Hector. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Marin, Raúl Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Kembro, Jackelyn Melissa. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Kembro, Jackelyn Melissa. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina

Dust-bathing behavior of laying hens in enriched colony housing systems and an aviary system

The dust-bathing behavior of Lohmann Selected Leghorn hens was compared in 4 enriched colony housing systems and in an aviary system. The enriched colony housing systems differed especially in the alignment and division of the functional areas dust bath, nest, and perches. Forty-eight-hour video recordings were performed at 3 time-points during the laying period, and focal animal sampling and behavior sampling methods were used to analyze the dust-bathing behavior. Focal animal data included the relative fractions of dust-bathing hens overall, of hens bathing in the dust-bath area, and of those bathing on the wire floor throughout the day. Behavior data included the number of dust-bathing bouts within a predefined time range, the duration of 1 bout, the number of and reasons for interruptions, and the number of and reasons for the termination of dust-bathing bouts. Results showed that the average duration of dust bathing varied between the 4 enriched colony housing systems compared with the aviary system. The duration of dust-bathing bouts was shorter than reported under natural conditions. A positive correlation between dust-bathing activity and size of the dust-bath area was observed. Frequently, dust baths were interrupted and terminated by disturbing influences such as pecking by other hens. This was especially observed in the enriched colony housing systems. In none of the observed systems, neither in the enriched colony housing nor in the aviary system, were all of the observed dust baths terminated “normally.” Dust bathing behavior on the wire mesh rather than in the provided dust-bath area generally was observed at different frequencies in all enriched colony housing systems during all observation periods, but never in the aviary system. The size and design of the dust-bath area influenced the prevalence of dust-bathing behavior in that small and subdivided dust-bath areas reduced the number of dust-bathing bouts but increased the incidence of sham dust bathing on the wire mesh

Relationships between fetal body weight of Wistar rats at term and the extent of skeletal ossification

We investigated the relationship between fetal body weight at term (pregnancy day 21) and the extent of ossification of sternum, metacarpus, metatarsus, phalanges (proximal, medial and distal) of fore- and hindlimbs and cervical and coccygeal vertebrae in Wistar rats. The relationships between fetal body weight and sex, intrauterine position, uterine horn, horn size, and litter size were determined using historical control data (7594 fetuses; 769 litters) of untreated rats. Relationships between body weight and degree of ossification were examined in a subset of 1484 historical control fetuses (154 litters) which were subsequently cleared and stained with alizarin red S. Fetal weight was independent of horn size, uterine horn side (left or right) or intrauterine position. Males were heavier than females and fetal weight decreased with increasing litter size. Evaluation of the skeleton showed that ossification of sternum, metacarpus and metatarsus was extensively complete and independent of fetal weight on pregnancy day 21. In contrast, the extent of ossification of fore- and hindlimb phalanges and of cervical and sacrococcygeal vertebrae was dependent on fetal body weight. The strongest correlation between body weight and degree of ossification was found for hindlimb, medial and proximal phalanges. Our data therefore suggest that, in full-term rat fetuses (day 21), reduced ossification of sternum, metacarpus and metatarsus results from a localized impairment of bone calcification (i.e., a malformation or variation) rather than from general growth retardation and that ossification of hindlimb (medial and proximal) phalanges is a good indicator of treatment-induced fetal growth retardation