Frugivory by Small Vertebrates Within a Deforested, Dry Tropical Region of Central America

Small vertebrates were inventoried within three habitat types in a degraded dry forest region of Panama. Animals were classified as frugivorous if they were observed foraging on fruit or if fecal samples contained mostly or exclusively seeds. Overall, we found that eight bat species and 21 bird species consumed fruit. The greatest numbers of birds were observed within live fences and bird species richness was greatest within riparian forests. Bat assemblages were not significantly different between habitats. The implication is that ecosystem services such as seed dispersal may still be functional in this landscape.     

Retrieval Intention Modulates the Effects of Directed Forgetting Instructions on Recollection

The neurocognitive basis of memory retrieval is often examined by investigating brain potential old/new effects, which are differences in brain activity between successfully remembered repeated stimuli and correctly rejected new stimuli in a recognition test. In this study, we combined analyses of old/new effects for words with an item-method directed-forgetting manipulation in order to isolate differences between the retrieval processes elicited by words that participants were initially instructed to commit to memory and those that participants were initially instructed to forget. We compared old/new effects elicited by to-be-forgotten (TBF) words with those elicited by to-be-remembered (TBR) words in both an explicit-memory test (a recognition test) and an implicit-memory test (a lexical-decision test). Behavioral results showed clear directed forgetting effects in the recognition test, but not in the lexical decision test. Mirroring the behavioral findings, analyses of brain potentials showed evidence of directed forgetting only in the recognition test. In this test, potentials from 450–650 ms (P600 old/new effects) were more positive for TBR relative to TBF words. By contrast, P600 effects evident during the lexical-decision test did not differ in magnitude between TBR and TBF items. When taken in the context of prior studies that have linked similar parietal old/new effects to the recollection of episodic information, these data suggest that directed-forgetting effects manifest primarily in greater episodic retrieval by TBR than TBF items, and that retrieval intention may be important for these directed-forgetting effects to occur.     

Trends in Resource Utilization by Children with Neurological Impairment in the United States Inpatient Health Care System: A Repeat Cross-Sectional Study

Background

Care advances in the United States (US) have led to improved survival of children with neurological impairment (NI). Children with NI may account for an increasing proportion of hospital resources. However, this assumption has not been tested at a national level.

Methods and Findings

We conducted a study of 25,747,016 US hospitalizations of children recorded in the Kids'' Inpatient Database (years 1997, 2000, 2003, and 2006). Children with NI were identified with International Classification of Diseases, 9th Revision, Clinical Modification diagnoses resulting in functional and/or intellectual impairment. We assessed trends in inpatient resource utilization for children with NI with a Mantel-Haenszel chi-square test using all 4 y of data combined. Across the 4 y combined, children with NI accounted for 5.2% (1,338,590) of all hospitalizations. Epilepsy (52.2% [n = 538,978]) and cerebral palsy (15.9% [n = 164,665]) were the most prevalent NI diagnoses. The proportion of hospitalizations attributable to children with NI did not change significantly (p = 0.32) over time. In 2006, children with NI accounted for 5.3% (n = 345,621) of all hospitalizations, 13.9% (n = 3.4 million) of bed days, and 21.6% (US$17.7 billion) of all hospital charges within all hospitals. Over time, the proportion of hospitalizations attributable to children with NI decreased within non-children''s hospitals (3.0% [n = 146,324] in 1997 to 2.5% [n = 113,097] in 2006, p<.001) and increased within children''s hospitals (11.7% [n = 179,324] in 1997 to 13.5% [n = 209,708] in 2006, p<0.001). In 2006, children with NI accounted for 24.7% (2.1 million) of bed days and 29.0% (US$12.0 billion) of hospital charges within children''s hospitals.

Conclusions

Children with NI account for a substantial proportion of inpatient resources utilized in the US. Their impact is growing within children''s hospitals. We must ensure that the current health care system is staffed, educated, and equipped to serve this growing segment of vulnerable children. Please see later in the article for the Editors'' Summary     

The Effect of Conflicting Pressures on the Evolution of Division of Labor

Within nature, many groups exhibit division of labor. Individuals in these groups are under seemingly antagonistic pressures to perform the task most directly beneficial to themselves and to potentially perform a less desirable task to ensure the success of the group. Performing experiments to study how these pressures interact in an evolutionary context is challenging with organic systems because of long generation times and difficulties related to group propagation and fine-grained control of within-group and between-group pressures. Here, we use groups of digital organisms (i.e., self-replicating computer programs) to explore how populations respond to antagonistic multilevel selection pressures. Specifically, we impose a within-group pressure to perform a highly-rewarded role and a between-group pressure to perform a diverse suite of roles. Thus, individuals specializing on highly-rewarded roles will have a within-group advantage, but groups of such specialists have a between-group disadvantage. We find that digital groups could evolve to be either single-lineage or multi-lineage, depending on experimental parameters. These group compositions are reminiscent of different kinds of major evolutionary transitions that occur within nature, where either relatives divide labor (fraternal transitions) or multiple different organisms coordinate activities to form a higher-level individual (egalitarian transitions). Regardless of group composition, organisms embraced phenotypic plasticity as a means for genetically similar individuals to perform different roles. Additionally, in multi-lineage groups, organisms from lineages performing highly-rewarded roles also employed reproductive restraint to ensure successful coexistence with organisms from other lineages.     

Formation of the gap junction nexus: binding partners for connexins.

Gap junctions are the morphological correlates of direct cell-cell communication and are formed of hexameric assemblies of gap junction proteins (connexins) into hemichannels (or connexons) provided by each coupled cell. Gap junction channels formed by each of the connexin subtypes (of which there are as many as 20) display different properties, which have been attributed to differences in amino acid sequences of gating domains of the connexins. Recent studies additionally indicate that connexin proteins interact with other cellular components to form a protein complex termed the Nexus. This review summarizes current knowledge regarding the protein-protein interactions involving of connexin proteins and proposes hypothesized functions for these interactions.     

A tetrameric allyl complex of sodium, and computational modeling of the Na-allyl chemical shift

Transmetallation of Li[A′] (A′ = [1,3-(SiMe₃)₂C₃H₃]⁻) with sodium tert-butoxide produces the corresponding sodium salt, which crystallizes from THF/toluene in the form of a cyclic tetramer, {Na[A′](thf)}₄. The Na atoms are in a square planar arrangement, bridged with π-bound allyl ligands; the Na-C distances range from 2.591(3)-2.896(3) Å, with an average of 2.70 Å. The geometries of several model organosodium complexes containing cyclopentadienyl and allyl ligands were optimized with density functional theory methods. The optimized structures were used with the gauge-including atomic orbital (GIAO) method to calculate their ²³Na NMR magnetic shielding values. Unlike the case with NaCp, the chemical shift of unsubstituted Na(C₃H₅) is very sensitive to the presence of coordinated THF (causing a 20 ppm upfield shift); silyl substitution has an even larger effect (30 ppm upfield shift). The observed ²³Na shift of δ −3.3 ppm for Na[A′] in THF-d₈, however, cannot be reliably distinguished from that calculated for the [Na(thf)₄]⁺ cation alone.     

Exome Sequencing Identifies Rare Deleterious Mutations in DNA Repair Genes FANCC and BLM as Potential Breast Cancer Susceptibility Alleles

Despite intensive efforts using linkage and candidate gene approaches, the genetic etiology for the majority of families with a multi-generational breast cancer predisposition is unknown. In this study, we used whole-exome sequencing of thirty-three individuals from 15 breast cancer families to identify potential predisposing genes. Our analysis identified families with heterozygous, deleterious mutations in the DNA repair genes FANCC and BLM, which are responsible for the autosomal recessive disorders Fanconi Anemia and Bloom syndrome. In total, screening of all exons in these genes in 438 breast cancer families identified three with truncating mutations in FANCC and two with truncating mutations in BLM. Additional screening of FANCC mutation hotspot exons identified one pathogenic mutation among an additional 957 breast cancer families. Importantly, none of the deleterious mutations were identified among 464 healthy controls and are not reported in the 1,000 Genomes data. Given the rarity of Fanconi Anemia and Bloom syndrome disorders among Caucasian populations, the finding of multiple deleterious mutations in these critical DNA repair genes among high-risk breast cancer families is intriguing and suggestive of a predisposing role. Our data demonstrate the utility of intra-family exome-sequencing approaches to uncover cancer predisposition genes, but highlight the major challenge of definitively validating candidates where the incidence of sporadic disease is high, germline mutations are not fully penetrant, and individual predisposition genes may only account for a tiny proportion of breast cancer families.     

The Role of Compassion in Altruistic Helping and Punishment Behavior

Compassion, the emotional response of caring for another who is suffering and that results in motivation to relieve suffering, is thought to be an emotional antecedent to altruistic behavior. However, it remains unclear whether compassion enhances altruistic behavior in a uniform way or is specific to sub-types of behavior such as altruistic helping of a victim or altruistic punishment of a transgressor. We investigated the relationship between compassion and subtypes of altruistic behavior using third-party paradigms where participants 1) witnessed an unfair economic exchange between a transgressor and a victim, and 2) had the opportunity to either spend personal funds to either economically a) help the victim or b) punish the transgressor. In Study 1, we examined whether individual differences in self-reported empathic concern (the emotional component of compassion) was associated with greater altruistic helping or punishment behavior in two independent samples. For participants who witnessed an unfair transaction, trait empathic concern was associated with greater helping of a victim and had no relationship to punishment. However, in those who decided to punish the transgressor, participants who reported greater empathic concern decided to punish less. In Study 2, we directly enhanced compassion using short-term online compassion meditation training to examine whether altruistic helping and punishment were increased after two weeks of training. Compared to an active reappraisal training control group, the compassion training group gave more to help the victim and did not differ in punishment of the transgressor. Together, these two studies suggest that compassion is related to greater altruistic helping of victims and is not associated with or may mitigate altruistic punishment of transgressors.