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Landscape connectivity is an important component of systematic conservation planning. Step‐selection functions (SSFs) is a highly promising method for connectivity modeling. However, differences in movement behavior across individuals and seasons are usually not considered in current SSF‐based analyses, potentially leading to imprecise connectivity models. Here, our objective was to use SSFs to build functional connectivity models for African elephants Loxodonta africana in a seasonal environment to illustrate the temporal variability of functional landscape connectivity. We provide a methodological framework for integrating detected inter‐individual variability into resistance surface modeling, for assessing how landscape connectivity changes across seasons, and for evaluating how seasonal connectivity differences affect predictions of movement corridors. Using radio‐tracking data from elephants in the Borderland area between Kenya and Tanzania, we applied SSFs to create seasonal landscape resistance surfaces. Based on seasonal models, we predicted movement corridors connecting major protected areas (PAs) using circuit theory and least‐cost path analysis. Our findings demonstrate that individual variability and seasonality lead to substantial changes in landscape connectivity and predicted movement corridors. Specifically, we show that the models disregarding seasonal resource fluctuations underestimate connectivity for the wet and transitional seasons, and overestimate connectivity for the dry season. Based on our seasonal models, we predicted a connectivity network between large PAs and highlight seasonal and consistent patterns that are most important for effective management planning. Our findings reveal that elephant movements in the borderland between Kenya and Tanzania are essential for maintaining connectivity in the dry season, and that existing corridors do not protect these movements in full extent. African elephants moving through Amboseli National Park. [ABSTRACT FROM AUTHOR]

In this study, the levels of salivary IgG1, IgG2, IgG3 and IgG4 from individuals with and without homozygous immunoglobulin heavy chain constant gene deletions were quantified by enzyme- linked immunosorbent assay (ELISA). To analyse the restriction of salivary IgG subclasses, we used unstimulated whole saliva and sera collected at the same time from individuals with homozygous gene deletions, two with G1 deletion, one with G4 deletion, six with both G2 and G4 deletions and from eight individuals without IGHG gene deletions and expressing all four IgG subclasses. The median values of salivary IgG from individuals with homozygous G1, or G4, or both G2 and G4 deletions, and from individuals expressing all four subclasses were 24·2 mg/l and 23·4 mg/l, respectively. The median values of serum IgG were 13·7 g/I and 15·9 g/l, respectively. Our results show that the salivary and serum IgG levels were both within the normal range in individuals with homozygous gene deletions of either Gl, or G4, or both G2 and G4. [ABSTRACT FROM AUTHOR]

This article examines evidence for elevations in basal metabolic rate (BMR) among indigenous Northern (circumpolar) populations and considers potential mechanisms and the adaptive basis for such elevations. Data on BMR among indigenous (n = 109 males; 122 females) and nonindigenous (n = 15 males; 22 females) circumpolar groups of North America and Siberia are compiled and compared to predicted BMRs based on three different references: body surface area (Consolazio et al., 1963), body mass (Schofield, 1985), and fat-free mass (Poehlman and Toth, 1995). Regardless of which reference is used, indigenous circumpolar groups show systematic and statistically significant elevations in BMR ranging from +7% to +19% above predicted values for indigenous men and from +3 to +17% for indigenous women. Nonindigenous males also show elevations in BMR, although not to the same extent as in indigenous men (deviations = +3 to +14%), whereas nonindigenous females show no clear evidence of elevated BMRs (deviations = -7 to +5%). This pattern of variation between indigenous and nonindigenous groups suggests that both functional and genetic factors play a role in metabolic adaptation to northern climes. Recent studies on the ecology and genetics of thyroid function offer insights into the mechanisms through which indigenous circumpolar populations may regulate metabolic rates. Studies of seasonal variation in thyroid hormone levels suggest that indigenous circumpolar populations may have a greater capacity to elevate BMR during severe cold than nonindigenous groups. Recent twin studies indicate a significant genetic component of thyroid responses to environmental stressors. Further research exploring the genetics of seasonal variation in thyroid function and BMR among circumpolar groups would advance understanding of the role that selection may have played in shaping metabolic variation., (Copyright 2002 Wiley-Liss, Inc.)

Five polymorphisms involving two paternally inherited loci were surveyed in 38 world populations (n = 1,631) to investigate the origins of Native Americans. One of the six Y chromosome combination haplotypes (1T) was found at relatively high frequencies (17.8-75.0%) in nine Native American populations (n = 206) representing the three major linguistic divisions in the New World. Overall, these data do not support the Greenberg et al. (1986) tripartite model for the early peopling of the Americas. The 1T haplotype was also discovered at a low frequency in Siberian Eskimos (3/22), Chukchi (1/6), and Evens (1/65) but was absent from 17 other Asian populations (n = 987). The perplexing presence of the 1T haplotype in northeastern Siberia may be due to back-migration from the New World to Asia.

The addition of human serum albumin (HSA) to peritoneal dialysate increases the clearance of bilirubin in rats suffering from obstructive jaundice. The acceptor properties of the fluid can be enhanced by using HSA that does not contain standard stabilizing additives and has been purified by further adsorption on activated carbon. Bilirubin-containing dialysate fluid, as well as the ascitic fluid of cirrhotic patients, can be regenerated by a combination of membrane ultrafiltration and carbon adsorption. These observations suggest a potentially useful scheme for continuous, regenerative peritoneal dialysis in the treatment of hepatic insufficiency.

Phenotype and allelic frequencies for ABO, MNSs, P, Rh, Kell, Duffy, and Diego blood groups, as well as for transferrins (Tf), haptoglobins (Hp), phosphoglucomutase 1 (PGM1), adenylate kinase (AK), 6-phosphogluconate dehydrogenase (PGD), and acid phosphatase (AcP) are described in 9-10 adjoining populations of Reindeer Chukchi. Additionally, one of three presently existing territorial subgroups of Siberian Eskimos was studied. The total sample size ranges from 931 to 1,066 in Chukchi, and from 99 to 102 in Eskimos, depending on the genetic system studied. Substantially reduced samples for Kidd and ABO secretion were investigated solely in the Reindeer Chukchi. Significant heterogeneity of allelic frequencies has been observed among Chukchi populations (X(2)124 = 378.47, P less than 0.001). Summed genetic heterogeneity between Reindeer Chukchi and Siberian Eskimos was also found to be highly significant (X(2)14 = 186.54, P less than 0.001). Both groups can be readily discriminated with only four outliers: Ns, P1, R1, and pa. Random genetic drift is suggested to be responsible for a large proportion of heterogeneity of allelic frequencies at the MNSs, P, and Rh blood-group system sites both among the Chukchi and Eskimos. Conversely, stabilizing selection is assumed as the principal agent maintaining homogeneous allelic frequencies at the AcP locus within the Chukchi subdivisions, whereas disruptive selection may be considered as a major factor leading to different Pa frequencies between Chukchi and Eskimos.

The Nganasans are made up of two recently tribal populations. These, the Avam and Vadey, were established in the seventeenth century from small reindeer hunting bands, themselves apparently descended from the Yukaghir. Data on 13 blood systems have been described for the first time in the Vadey Nganasans, and the results compared with those previously reported for the two Avam subgroups. As a whole, the Nganasans are characterized by low frequency of B blood group, high frequencies of Ns, cDE, Fy(a), Hp(2), absence of A2, P(c), K, and apparently an absence of cde alleles or haplotypes. Measurement of intrapopulation heterogeneity reveals significant divergence among the two Avam subdivisions (chi 2/16=57.59; P less than 0.001), as well as between the total Avam and Vadey (chi 2/17=79.31; P less than 0.001). Founder principle, and local genetic drift, are believed to account for the greater difference between the Avam and Vadey subgroups than that observed between the two Avam populations. The Nganasans of the Taimir Peninsula appear to be the last group of reindeer hunters remaining in Northern Siberia. For ages they have lived in relative isolation, and therefore are the least touched genetically, either by surrounding herding groups originating in Southern Siberia, or by recent Caucasian admixture.