The fish fauna of the Iwokrama Forest

Fishes were collected from the rivers in and around the Iwokrama Forest during January-February and November-December 1997. Four hundred species of fish were recorded from forty families in ten orders. Many of these fishes are newly recorded from Guyana and several are thought to be endemic. The number of species recorded for the area is surprising given the low level of effort and suggests that this area may be particularly important from a fish diversity perspective. This paper focuses on species of particular interest from a management perspective including those considered economically important, rare or endangered. The paper is also the basis for developing fisheries management systems in the Iwokrama Forest and Rupununi Wetlands

In vivo DNA assembly using common laboratory bacteria: A re-emerging tool to simplify molecular cloning

Molecular cloning is a cornerstone of biomedical, biotechnological, and synthetic biology research. As such, improved cloning methodologies can significantly advance the speed and cost of research projects. Whereas current popular cloning approaches use in vitro assembly of DNA fragments, in vivo cloning offers potential for greater simplification. It is generally assumed that bacterial in vivo cloning requires Escherichia coli strains with enhanced recombination ability; however, this is incorrect. A widely present, bacterial RecA-independent recombination pathway is re-emerging as a powerful tool for molecular cloning and DNA assembly. This poorly understood pathway offers optimal cloning properties (i.e. seamless, directional, and sequence-independent) without requiring in vitro DNA assembly or specialized bacteria, therefore vastly simplifying cloning procedures. Although the use of this pathway to perform DNA assembly was first reported over 25 years ago, it failed to gain popularity, possibly due to both technical and circumstantial reasons. Technical limitations have now been overcome, and recent reports have demonstrated its versatility for DNA manipulation. Here, we summarize the historical trajectory of this approach and collate recent reports to provide a roadmap for its optimal use. Given the simplified protocols and minimal requirements, cloning using in vivo DNA assembly in E. coli has the potential to become widely employed across the molecular biology community

Rescaling resettlement: how meso-level actors shape refugee policy

This dissertation examines the processes and outcomes of the United States’ refugee resettlement policy. Specifically, I ask: how are refugees selected? How are refugees processed abroad? And how are refugees incorporated once they arrive? Drawing on statistical analysis of previously unreleased government data, 150 interviews, and nineteen months of ethnographic fieldwork across the transnational chain of resettlement, this study examines the logics of practice and patterned interactions—among refugees, civil society, and state agencies—that shape outcomes of resettlement. The predominant framework to understand resettlement posits a relatively straightforward reintegration of refugees into national citizenship regimes. In contrast, this dissertation demonstrates how constructions of refugees as “ideal beneficiaries” produced through meso-level social processes shape the distribution of scarce humanitarian resources and the experiences of refugees. I also show that refugees respond to these constructions in complex ways, sometimes internalizing them and sometimes challenging them, thereby creating social dynamics and subjectivities not accounted for by the predominant framework. I develop the above argument across three empirical chapters, each examining a distinct stage of resettlement: selection, processing, and reception. To explain how refugees are selected, I draw attention to a transnational social system of constructing “clean cases.” These are cases that can be identified and processed in stable and predictable ways to meet US admission demands under complex constraints. This system concentrates spaces around a relatively small number of groups, undermining humanitarian ideals of distributional equality. Examining social dynamics of processing, I find that frontline practitioners in Uganda grapple with refugees’ expectations of attaining resettlement and the reality of limited spaces and long, uncertain wait times. Practitioners respond by creating physical barriers and administrative procedures that force refugees to wait and be patient. These findings challenge straightforward notions of resettlement as “solution,” showing instead that processing involves coercion and compounds traumatic waiting. Lastly, at sites of reception, I find that local actors have rescaled federal resettlement policy, but that policies diverge across Atlanta and Pittsburgh because of their distinct histories. I term these local policies “urban incorporation regimes,” and show how they valorize different aspects of refugees’ identity, leading to place-based modes of identification

Molecular Mechanisms Controlling Excitatory Synaptic Transmission

At synapses, the sites of communication between neurons, neurotransmitter is released from the presynaptic cell and binds to postsynaptic receptors on another. In the case of excitatory synapses, the predominant neurotransmitter, L-glutamate, binds to postsynaptic AMPA receptors (AMPARs). Crucially, synaptic strength is plastic, and control of this strength is essential for fundamental brain functions such as the processing and storage of information. Synaptic transmission is controlled by tuning the response of postsynaptic receptors to glutamate release. This can be achieved by altering both the number and spatial positioning of receptors. The mechanisms governing AMPAR anchoring at postsynaptic sites have been intensely studied for many years, focussing on intracellular interactions with postsynaptic scaffold proteins, however, these interactions do not appear strictly essential to synaptic receptor anchoring. The receptor’s N-terminal domain (NTD) comprises 50 % of the protein, and extends into the synaptic cleft, towards the presynapse, offering great potential for subunit-specific receptor control, yet its influence on synaptic transmission remains elusive. Facilitated by the development of an optimised molecular cloning approach, this study uses a combination of electrophysiological and imaging methods to investigate the role of the AMPAR NTD at synaptic sites. It demonstrates that this domain has a critical role in anchoring the AMPAR at the synapse. Through subunit-specific interactions in the synaptic cleft, the NTD controls the number of receptors present at a synaptic connection. Receptors lacking the NTD are unable to properly anchor at synaptic sites, and are unable to facilitate synaptic plasticity such as long-term potentiation, despite robustly trafficking to the cell surface. When studied in comparison to other AMPAR anchoring interactions, NTD-dependent mechanisms appear to be more influential than classical models involving the intracellular C-terminal of the receptor. Given that NTD-dependent interactions will occur within the synaptic cleft, both pre and postsynaptic neurons have the potential to control and detect the strength of synaptic transmission. Therefore, this mechanism of AMPAR anchoring has profound implications when considering how information is stored at a synaptic connection.This thesis was funded by a Medical Research Council Studentship

A Case Report of Candida albicans Costochondritis after a Complicated Esophagectomy

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.We present an unusual case of Candida albicans costochondritis after a complicated Ivor Lewis esophagectomy. This case exhibits that pain, erythema, and swelling over the costal cartilages should alert the possibility of infective costochondritis, especially in a postoperative patient. If a fungal agent is identified, aggressive surgical debridement and early commencement of antifungal therapy are likely determinants for a satisfactory outcome

Molecular cloning using in vivo DNA assembly

Here we describe the in vivo DNA assembly approach, where molecular cloning procedures are performed using an E. coli recA-independent recombination pathway, which assembles linear fragments of DNA with short homologous termini. This pathway is present in all standard laboratory E. coli strains and, by bypassing the need for in vitro DNA assembly, allows simplified molecular cloning to be performed without the plasmid instability issues associated with specialized recombination-cloning bacterial strains. The methodology requires specific primer design and can perform all standard plasmid modifications (insertions, deletions, mutagenesis, and sub-cloning) in a rapid, simple, and cost-efficient manner, as it does not require commercial kits or specialized bacterial strains. Additionally, this approach can be used to perform complex procedures such as multiple modifications to a plasmid, as up to 6 linear fragments can be assembled in vivo by this recombination pathway. Procedures generally require less than 3 h, involving PCR amplification, DpnI digestion of template DNA, and transformation, upon which circular plasmids are assembled. In this chapter we describe the requirements, procedure, and potential pitfalls when using this technique, as well as protocol variations to overcome the most common issues

AMPA receptor anchoring at CA1 synapses is determined by N-terminal domain and TARP γ8 interactions.

AMPA receptor (AMPAR) abundance and positioning at excitatory synapses regulates the strength of transmission. Changes in AMPAR localisation can enact synaptic plasticity, allowing long-term information storage, and is therefore tightly controlled. Multiple mechanisms regulating AMPAR synaptic anchoring have been described, but with limited coherence or comparison between reports, our understanding of this process is unclear. Here, combining synaptic recordings from mouse hippocampal slices and super-resolution imaging in dissociated cultures, we compare the contributions of three AMPAR interaction domains controlling transmission at hippocampal CA1 synapses. We show that the AMPAR C-termini play only a modulatory role, whereas the extracellular N-terminal domain (NTD) and PDZ interactions of the auxiliary subunit TARP γ8 are both crucial, and each is sufficient to maintain transmission. Our data support a model in which γ8 accumulates AMPARs at the postsynaptic density, where the NTD further tunes their positioning. This interplay between cytosolic (TARP γ8) and synaptic cleft (NTD) interactions provides versatility to regulate synaptic transmission and plasticity

Can the Nordic Hamstring Test Identify Collegiate Athletes at Risk for a Time-Loss Hamstring Injury?

Why Nordic Hamstring? Hamstrings are the most commonly injured muscle in sprinting and kicking sports (soccer, football and rugby). Recurrent hamstring injuries lead to longer time loss than the original injury. Despite the presence of preventa- tive programs, research has not yet documented an effective, low-cost, widely accessible test to determine hamstring injury risk

Investigating the physical properties of transiting hot Jupiters with the 1.5-m Kuiper Telescope

We present new photometric data of 11 hot Jupiter transiting exoplanets (CoRoT-12b, HAT-P-5b, HAT-P-12b, HAT-P-33b, HAT-P-37b, WASP-2b, WASP-24b, WASP-60b, WASP-80b, WASP-103b, XO-3b) in order to update their planetary parameters and to constrain information about their atmospheres. These observations of CoRoT-12b, HAT-P-37b and WASP-60b are the first follow-up data since their discovery. Additionally, the first near-UV transits of WASP-80b and WASP-103b are presented. We compare the results of our analysis with previous work to search for transit timing variations (TTVs) and a wavelength dependence in the transit depth. TTVs may be evidence of a third body in the system and variations in planetary radius with wavelength can help constrain the properties of the exoplanet's atmosphere. For WASP-103b and XO-3b, we find a possible variation in the transit depths that may be evidence of scattering in their atmospheres. The B-band transit depth of HAT-P-37b is found to be smaller than its near-IR transit depth and such a variation may indicate TiO/VO absorption. These variations are detected from 2-4.6$\sigma$, so follow-up observations are needed to confirm these results. Additionally, a flat spectrum across optical wavelengths is found for 5 of the planets (HAT-P-5b, HAT-P-12b, WASP-2b, WASP-24b, WASP-80b), suggestive that clouds may be present in their atmospheres. We calculate a refined orbital period and ephemeris for all the targets, which will help with future observations. No TTVs are seen in our analysis with the exception of WASP-80b and follow-up observations are needed to confirm this possible detection.Comment: 18 pages, 7 figures, 9 Tables. Light Curves available online. Accepted to MNRAS (2017 August 25