Predation Threat in a Variable Landscape: Connecting Predation Risk to Nesting Success for the Seaside Sparrow (Ammospiza maritima macgilivraii)

Predation, the leading cause of nest-failure in birds, not only exists as a direct threat to nesting success, but may exacerbate other sources of nest mortality. Birds inhabiting Atlantic coastal marshes, such as Seaside Sparrows (Ammospiza maritima; hereafter SESP), are experiencing significant and rapid changes to their habitat, particularly sea level rise (SLR) and encroaching urbanization, that may affect the relative influence of nest predation on overall productivity. For SESPs, SLR presents an inherent threat to nest success in its potential to increase the frequency of nest flooding. In addition to this direct threat, the ability of SESPs to adaptively respond to SLR can be constrained by predation pressure. As SESPs elevate their nests to avoid flooding, their nests become more vulnerable to predation. This research aimed to understand the predictability of SESP nest predation in Georgia’s saltmarshes along two major gradients: distance to roads and distance to tidal rivers (rivers ≥ 45m wide), both of which may be attractants for predators in the marsh. In coastal Georgia, USA, I assessed mammalian predator activity, an index for mammalian predator distribution, along the two gradients of interest, and hypothesized that predator activity would be higher close to roads and tidal rivers. Second, I recorded SESP nest predation events and hypothesized that nest predation events would increase with increasing probability of predator presence. Consistent with my hypothesis, predator activity increased close to roads and tidal rivers. However, mammalian predator distribution did not predict the spatial variation in SESP nest predation. Given my findings regarding predator distribution in the saltmarsh, I recommend that management efforts to decrease predator access to SESP habitat focus on road-marsh edges, particularly if they are connected with urban landscapes. Understanding the predictability of mammalian predator distribution equips us with valuable information for crafting conservation strategies for SESPs, such as predator management, that would relax the constraint of nest predation on their ability to respond to the ever-intensifying threat of SLR

Factors Influencing Individual Performance in an Indonesian Government Office

Reformation in Indonesian government offices leads to many substantial changes, and demands improved job performances while arguably loading employees with more work. This research aims to understand factors that potentially influence job performance in Indonesian government offices that carries on such reformation. Using adapted scales from previous studies, this research investigates the role of workload, responsibility for others (level of responsibility to care for other people) and need for achievement on employee’s performance.  A survey to all full-time workers in an Indonesian government office is conducted. Contrary to expectation, workload does not influence employee’s performance. Instead, regression analysis demonstrates that, employee’s need for achievement and responsibility for others are significant factors affecting individual performance. These results are important because they highlight the significance of need for achievement for the success of reformation in this office, and by extension for reformation in Indonesia. The results are also interesting because this is the first study that points out to the role of responsibility for others in influencing individual performance in Indonesia which is characterized by collectivistic culture. This paper discusses the contributions of these results for theory and practice. &nbsp

Zenker’s diverticulum and squamous esophageal cancer: a case report

Zenker’s diverticulum represents a rare esophageal lesion developed especially in the elderly population due to herniation of esophageal mucosa above the cricopharyngeus muscle. The condition leads to food retention, regurgitation, aspiration, and dysphagia in affected patients. Progressive dysphagia also characterizes malignant diseases of the esophagus like squamous esophageal carcinoma that typically appears in male patients in the seventh decade of life, with a history of cigarette smoking and alcohol abuse. We report a case of a male patient who presented with dysphagia for both solids and liquids along with significant weight loss, and who was diagnosed with medium esophageal cancer associated with Zenker’s diverticulum

Marine viruses:key players in marine ecosystems

Viruses were recognized as the causative agents of fish diseases, such as infectious pancreatic necrosis and Oregon sockeye disease, in the early 1960s [1], and have since been shown to be responsible for diseases in all marine life from bacteria to protists, mollusks, crustaceans, fish and mammals [2].[...

Exploring Bluetooth based Mobile Phone Interaction with the Hermes Photo Display

One of the most promising possibilities for supporting user interaction with public displays is the use of personal mobile phones. Furthermore, by utilising Bluetooth users should have the capability to interact with displays without incurring personal financial connectivity costs. However, despite the relative maturity of Bluetooth as a standard and its widespread adoption in today’s mobile phones, little exploration seems to have taken place in this area - despite its apparent significant potential. This paper describe the findings of an exploratory study nvolving our Hermes Photo Display which has been extended to enable users with a suitable phone to both send and receive pictures over Bluetooth. We present both the technical challenges of working with Bluetooth and, through our user study, we present initial insights into general user acceptability issues and the potential for such a display to facilitate notions of community

Modifications to the Aesop's Fable paradigm change New Caledonian crow performances

While humans are able to understand much about causality, it is unclear to what extent non-human animals can do the same. The Aesop's Fable paradigm requires an animal to drop stones into a water-filled tube to bring a floating food reward within reach. Rook, Eurasian jay, and New Caledonian crow performances are similar to those of children under seven years of age when solving this task. However, we know very little about the cognition underpinning these birds' performances. Here, we address several limitations of previous Aesop's Fable studies to gain insight into the causal cognition of New Caledonian crows. Our results provide the first evidence that any non-human animal can solve the U-tube task and can discriminate between water-filled tubes of different volumes. However, our results do not provide support for the hypothesis that these crows can infer the presence of a hidden causal mechanism. They also call into question previous object-discrimination performances. The methodologies outlined here should allow for more powerful comparisons between humans and other animal species and thus help us to determine which aspects of causal cognition are distinct to humans.Publisher PDFPeer reviewe

Entire solutions blowing up at infinity for semilinear elliptic systems

AbstractWe consider the system Δu=p(x)g(v), Δv=q(x)f(u) in RN, where f,g are positive and non-decreasing functions on (0,∞) satisfying the Keller–Osserman condition and we establish the existence of positive solutions that blow-up at infinity

Parameter estimation method using an extended Kalman Filter

Fast parameter estimation is a non-trivial task, and it is critical when the system parameters evolve with time, as demanded in real-time control applications. In this study, a new computational approach for parameter identification is proposed based on the application of polynomial chaos theory. The polynomial chaos approach has been shown to be considerably more efficient than Monte Carlo in the simulation of systems with a small number of uncertain parameters. In the framework of this new approach, a (suboptimal) Extended Kalman Filter (EKF) is used to recalculate the polynomial chaos expansions for the uncertain states and the uncertain parameters. As a case study, the proposed parameter estimation method is applied to a four degree-of-freedom roll plane model of a vehicle for which the vertical stiffnesses of the tires are estimated from periodic observations of the displacements and velocities across the suspensions. The results obtained with this approach are close to the actual values of the parameters. In addition, the EKF approach gives more information about the parameters of interest than a simple estimated value: the estimation comes in the form of a probability density function. The approach presented in this paper has shown great promise for an improvement in the computational efficiency of current parameter estimation methods. Possible applications of this theory to the field of off-road vehicle simulations include the estimation of various vehicle parameters of interest, as well as the estimation of parameters related to the tire-terrain contact

The role of ras gene in the development of haemic neoplasia in Mytilus trossulus

Disseminated neoplasia has been reported in mussels (Mytilus spp) from numerous locations worldwide. This condition is progressive and fatal and the aetiology is unknown. In vertebrates, oncogenes such as ras, and tumour suppressor genes such as p53, play important roles in carcinogenesis. We have cloned a Mytilus trossulus homologue of the vertebrate ras gene, which shows conserved sequence in regions of functional importance. Neoplastic hemolymph samples derived from M. trossulus have been investigated for the presence of ras gene mutations and changes in expression

Optimization of a Ribosomal Structural Domain by Natural Selection

A conserved, independently folding domain in the large ribosomal subunit consists of 58 nt of rRNA and a single protein, L11. The tertiary structure of an rRNA fragment carrying the Escherichia coli sequence is marginally stable in vitro but can be substantially stabilized by mutations found in other organisms. To distinguish between possible reasons why natural selection has not evolved a more stable rRNA structure in E. coli, mutations affecting the rRNA tertiary structure were assessed for their in vitro effects on rRNA stability and L11 affinity (in the context of an rRNA fragment) or in vivo effects on cell growth rate and L11 content of ribosomes. The rRNA fragment stabilities ranged from -4 to +9 kcal/mol relative to the wild-type sequence. Variants in the range of -4 to +5 kcal/mol had almost no observable effect in vivo, while more destabilizing mutations (\u3e7 kcal/mol) were not tolerated. The data suggest that the in vivo stability of the complex is roughly -6 kcal/mol and that any single tertiary interaction is dispensable for function as long as a minimum stability of the complex is maintained. On the basis of these data, it seems that the evolution of this domain has not been constrained by inherent structural or functional limits on stability. The estimated stability corresponds to only a few ribosomes per bacterial cell dissociated from L11 at any time; thus the selective advantage for any further increase in stability may be so small as to be outweighed by other competing selective pressures