Ultrafast Dynamics of Nitro−Nitrite Rearrangement and Dissociation in Nitromethane Cation

We report new insights into the ultrafast rearrange- ment and dissociation dynamics of nitromethane cation (NM+) using pump−probe measurements, electronic structure calculations, and ab initio molecular dynamics simulations. The “roaming” nitro−nitrite rearrangement (NNR) pathway involving large- amplitude atomic motion, which has been previously described for neutral nitromethane, is demonstrated for NM+. Excess energy resulting from initial population of the electronically excited D2 state of NM+ upon strong-field ionization provides the necessary energy to initiate NNR and subsequent dissociation into NO+. Both pump−probe measurements and molecular dynamics simulations are consistent with the completion of NNR within 500 fs of ionization with dissociation into NO+ and OCH3 occurring ∼30 fs later. Pump−probe measurements indicate that NO+ formation is in competition with the direct dissociation of NM+ to CH3+ and NO2. Electronic structure calculations indicate that a strong D0 → D1 transition can be excited at 650 nm when the C−N bond is stretched from its equilibrium value (1.48 Å) to 1.88 Å. On the other hand, relaxation of the NM+ cation after ionization into D0 occurs in less than 50 fs and results in observation of intact NM+. Direct dissociation of the equilibrium NM+ to produce NO2+ and CH3 can be induced with 650 nm excitation via a weakly allowed D0 → D2 transition

Ranging behaviour of Long-crested Eagles Lophaetus occipitalis in human-modified landscapes of KwaZulu-Natal, South Africa

The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban landscapes, is becoming increasingly important for conservationists in the context of unprecedented high rates of anthropogenic land use change. We studied the movement ecology of adult Long-crested Eagles Lophaetus occipitalis fitted with geographic positioning system transmitters in an agricultural landscape in KwaZulu-Natal Province, South Africa. Mean home ranges (± SD) of males and females estimated using the autocorrelated kernel density estimator (AKDE) method were 608 ± 552 ha (n = 5) and 664 ± 844 ha (n = 4), respectively. Core areas (KDEhref 50%) were estimated as 80 ± 38 ha and 39 ± 20 ha for males and females, respectively. We also recorded exploratory behaviour (in the form of long excursions) in two of the birds, of up to 49 km from the centre of their home range. The relatively small home ranges reported in this study are suggestive of productive foraging habitats whereby Long-crested Eagles can meet their energy requirements without having to travel long distances to obtain resources. Consistent with predictions, non-breeding male and female Long-crested Eagles showed similar ranging behaviour, which includes occasional exploratory behaviour.Le comportement des rapaces dans les environnements modifiés par l’homme, tels que les paysages agricoles et suburbains, devient de plus en plus important pour les défenseurs de la nature dans le contexte des taux élevés sans précédent de changement d’utilisation des terres par l’homme. Nous avons étudié l’écologie du mouvement des Aigles huppards adultes Lophaetus occipitalis équipés d’émetteurs de système de positionnement géographique dans un paysage agricole de la province du KwaZulu-Natal, en Afrique du Sud. Les domaines vitaux moyens (± SD) des mâles et des femelles estimés à l’aide de la méthode de l’estimateur de densité de noyau autocorrélé (AKDE) étaient respectivement de 608 ± 552 ha (n = 5) et 664 ± 844 ha (n = 4). Les zones centrales (KDEhref 50%) ont été estimées à 80 ± 38 ha et 39 ± 20 ha respectivement pour les mâles et les femelles. Nous avons également enregistré un comportement exploratoire (sous forme de longues excursions) chez deux des oiseaux, jusqu’à 49 km du centre de leur domaine vital. Les domaines vitaux relativement petits signalés dans cette étude suggèrent des habitats de gagnage productifs où l’Aigle huppard peut satisfaire ses besoins énergétiques sans avoir à parcourir de longues distances pour obtenir des ressources. Conformément aux prévisions, les Aigles huppards mâles et femelles non reproducteurs ont montré un comportement territorial similaire, y compris un comportement exploratoire occasionnel.http://www.tandfonline.com/loi/tost202021-08-06hj2020Mammal Research InstituteZoology and Entomolog

The Mayer-Rokitansky-Küster-Hauser syndrome (congenital absence of uterus and vagina) – phenotypic manifestations and genetic approaches

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome affects at least 1 out of 4500 women and has for a long time been considered as a sporadic anomaly. Congenital absence of upper vagina and uterus is the prime feature of the disease which, in addition, is often found associated with unilateral renal agenesis or adysplasia as well as skeletal malformations (MURCS association). The phenotypic manifestations of MRKH overlap various other syndromes or associations and thus require accurate delineation. Since MRKH manifests itself in males, the term GRES syndrome (Genital, Renal, Ear, Skeletal) might be more appropriate when applied to both sexes. The MRKH syndrome, when described in familial aggregates, seems to be transmitted as an autosomal dominant trait with an incomplete degree of penetrance and variable expressivity. This suggests the involvement of either mutations in a major developmental gene or a limited chromosomal deletion. Until recently progress in understanding the genetics of MRKH syndrome has been slow, however, now HOX genes have been shown to play key roles in body patterning and organogenesis, and in particular during genital tract development. Expression and/or function defects of one or several HOX genes may account for this syndrome

[Avian cytogenetics goes functional] Third report on chicken genes and chromosomes 2015

High-density gridded libraries of large-insert clones using bacterial artificial chromosome (BAC) and other vectors are essential tools for genetic and genomic research in chicken and other avian species... Taken together, these studies demonstrate that applications of large-insert clones and BAC libraries derived from birds are, and will continue to be, effective tools to aid high-throughput and state-of-the-art genomic efforts and the important biological insight that arises from them

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Problematizing fit and survival: transforming the law of requisite variety through complexity misalignment

The law of requisite variety is widely employed in management theorizing and is linked with core strategy themes such as contingency and fit. We reflect upon requisite variety as an archetypal borrowed concept. We contrast its premises with insights from the institutional literature and commitment literature, draw propositions that set boundaries to its applicability, and review the ramifications of what we call “complexity misalignment.” In this way we contradict foundational assumptions of the law, problematize adaptation- and survival-centric views of strategizing, and theorize the role of human agency in variously complex regimes

Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques for Analysis of Energetic Materials

Energetic materials and the unimolecular dissociation dynamics attributed to their initiation and subsequent bimolecular detonation have been a subject of interest for defense agencies such as the Department of Defense (DoD) for decades. The timescale in which these initial dynamics exist ranges from several picoseconds to dozens of femtoseconds, necessitating equally fast time-resolved experiments to capture and characterize these events. Our lab specializes in one such laser-based technique: femtosecond time-resolved mass spectrometry (FTRMS). FTRMS is an essentially nondiscriminatory pump-probe laser technique with nearly infinite modifications via pulse shaping, intensity, and wavelength modulation that can readily examine previously undefined dissociation pathways in energetic species, all while maintaining high mass resolution. The pump-probe experiments ionize the molecule and then induce selective fragmentation by populating electronic excited states. Measuring the resulting dissociation products will increase overall comprehension of the chemical reaction mechanisms and the timescales under which they operate. Not only have we FTRMS to probe dynamics of energetic molecules such as explosive simulants on the several dozen femtosecond timescale, but we also applied these same dynamics to quantify the composition of mixtures of nitrotoluene isomers. Finally, we have built a front-loading chamber that utilizes separate femtosecond desorption and postionization lasers to overcome the dependence on sample volatility. Various metals have been ablated and gases introduced to the chamber to both provide preliminary data as well as for optimization of ion collection and optics alignment. The end goal is to empirically capture the elusive initiation precursor ions of explosive molecules such as TNT, RDX, TATB, and HMX

Ranging behaviour of Long-crested Eagles Lophaetus occipitalis in human-modified landscapes of KwaZulu-Natal, South Africa

The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban landscapes, is becoming increasingly important for conservationists in the context of unprecedented high rates of anthropogenic land use change. We studied the movement ecology of adult Long-crested Eagles Lophaetus occipitalis fitted with geographic positioning system transmitters in an agricultural landscape in KwaZulu-Natal Province, South Africa. Mean home ranges (± SD) of males and females estimated using the autocorrelated kernel density estimator (AKDE) method were 608 ± 552 ha (n = 5) and 664 ± 844 ha (n = 4), respectively. Core areas (KDEhref 50%) were estimated as 80 ± 38 ha and 39 ± 20 ha for males and females, respectively. We also recorded exploratory behaviour (in the form of long excursions) in two of the birds, of up to 49 km from the centre of their home range. The relatively small home ranges reported in this study are suggestive of productive foraging habitats whereby Long-crested Eagles can meet their energy requirements without having to travel long distances to obtain resources. Consistent with predictions, non-breeding male and female Long-crested Eagles showed similar ranging behaviour, which includes occasional exploratory behaviour. Keywords: agricultural landscapes, GPS transmitter, home range estimate, rapto