An Investigation of Performance Appraisal With Recommendations for White Collar and Blue Collar Workers

The accurate evaluation of an employee\u27s performance, whether it be a salary or wage worker, is one of the most challenging problems confronting any organization. According to Lazer (1977), which is still true today, performance appraisal is absolutely necessary if an organization is to prosper in the highly competitive world of modern business. Regardless of all that has been written about the how and why of performance appraisal, there still seems to be constant problems and areas of clear disagreement. Published writings about performance appraisal cover approximately the past 30 years and deal mostly with private corporations. Before that, performance appraisal systems were used in the public sector, but the guidelines for their development and use were not widely circulated. As organizations developed and became larger, a discreet and persistent ethic evolved. This ethic said that if we grow, we ought to know more about whom to select, how to supervise, and how to assess performance for promotion and salary decisions. What had once been an informal process, with a good amount of flexibility, had to be changed and standardized for use with more employees at all levels in the organization (Keil, 1977)

CO J=2-1 line emission in cluster galaxies at z~1: fueling star formation in dense environments

We present observations of CO J=2-1 line emission in infrared-luminous cluster galaxies at z~1 using the IRAM Plateau de Bure Interferometer. Our two primary targets are optically faint, dust-obscured galaxies (DOGs) found to lie within 2 Mpc of the centers of two massive (>10^14 Msun) galaxy clusters. CO line emission is not detected in either DOG. We calculate 3-sigma upper limits to the CO J=2-1 line luminosities, L'_CO < 6.08x10^9 and < 6.63x10^9 K km/s pc^2. Assuming a CO-to-H_2 conversion factor derived for ultraluminous infrared galaxies in the local Universe, this translates to limits on the cold molecular gas mass of M_H_2 < 4.86x10^9 Msun and M_H_2 < 5.30x10^9 Msun. Both DOGs exhibit mid-infrared continuum emission that follows a power-law, suggesting that an AGN contributes to the dust heating. As such, estimates of the star formation efficiencies in these DOGs are uncertain. A third cluster member with an infrared luminosity, L_IR < 7.4x10^11 Lsun, is serendipitously detected in CO J=2-1 line emission in the field of one of the DOGs located roughly two virial radii away from the cluster center. The optical spectrum of this object suggests that it is likely an obscured AGN, and the measured CO line luminosity is L'_CO = (1.94 +/- 0.35)x10^10 K km/s pc^2, which leads to an estimated cold molecular gas mass M_H_2 = (1.55+/-0.28)x10^10 Msun. A significant reservoir of molecular gas in a z~1 galaxy located away from the cluster center demonstrates that the fuel can exist to drive an increase in star-formation and AGN activity at the outskirts of high-redshift clusters.Comment: 22 pages, 4 figures; accepted for publication in Ap

Star Formation and AGN Activity in Galaxy Clusters from z=1−2z=1-2: a Multi-wavelength Analysis Featuring HerschelHerschel/PACS

We present a detailed, multi-wavelength study of star formation (SF) and AGN activity in 11 near-infrared (IR) selected, spectroscopically confirmed, massive ($\gtrsim10^{14}\,\rm{M_{\odot}}$) galaxy clusters at $1<z<1.75$. Using new, deep $Herschel$/PACS imaging, we characterize the optical to far-IR spectral energy distributions (SEDs) for IR-luminous cluster galaxies, finding that they can, on average, be well described by field galaxy templates. Identification and decomposition of AGN through SED fittings allows us to include the contribution to cluster SF from AGN host galaxies. We quantify the star-forming fraction, dust-obscured SF rates (SFRs), and specific-SFRs for cluster galaxies as a function of cluster-centric radius and redshift. In good agreement with previous studies, we find that SF in cluster galaxies at $z\gtrsim1.4$ is largely consistent with field galaxies at similar epochs, indicating an era before significant quenching in the cluster cores ($r<0.5\,$Mpc). This is followed by a transition to lower SF activity as environmental quenching dominates by $z\sim1$. Enhanced SFRs are found in lower mass ($10.1< \log \rm{M_{\star}}/\rm{M_{\odot}}<10.8$) cluster galaxies. We find significant variation in SF from cluster-to-cluster within our uniformly selected sample, indicating that caution should be taken when evaluating individual clusters. We examine AGN in clusters from $z=0.5-2$, finding an excess AGN fraction at $z\gtrsim1$, suggesting environmental triggering of AGN during this epoch. We argue that our results $-$ a transition from field-like to quenched SF, enhanced SF in lower mass galaxies in the cluster cores, and excess AGN $-$ are consistent with a co-evolution between SF and AGN in clusters and an increased merger rate in massive haloes at high redshift.Comment: 26 pages, 14 figures, 6 tables with appendix, accepted for publication in the Astrophysical Journa

B vitamins in patients with recent transient ischaemic attack or stroke in the VITAmins TO Prevent Stroke (VITATOPS) trial:a randomised, double-blind, parallel, placebo-controlled trial

SummaryBackgroundEpidemiological studies suggest that raised plasma concentrations of total homocysteine might be a risk factor for major vascular events. Whether lowering total homocysteine with B vitamins prevents major vascular events in patients with previous stroke or transient ischaemic attack is unknown. We aimed to assess whether the addition of once-daily supplements of B vitamins to usual medical care would lower total homocysteine and reduce the combined incidence of non-fatal stroke, non-fatal myocardial infarction, and death attributable to vascular causes in patients with recent stroke or transient ischaemic attack of the brain or eye.MethodsIn this randomised, double-blind, parallel, placebo-controlled trial, we assigned patients with recent stroke or transient ischaemic attack (within the past 7 months) from 123 medical centres in 20 countries to receive one tablet daily of placebo or B vitamins (2 mg folic acid, 25 mg vitamin B6, and 0·5 mg vitamin B12). Patients were randomly allocated by means of a central 24-h telephone service or an interactive website, and allocation was by use of random permuted blocks stratified by hospital. Participants, clinicians, carers, and investigators who assessed outcomes were masked to the assigned intervention. The primary endpoint was the composite of stroke, myocardial infarction, or vascular death. All patients randomly allocated to a group were included in the analysis of the primary endpoint. This trial is registered with ClinicalTrials.gov, NCT00097669, and Current Controlled Trials, ISRCTN74743444.FindingsBetween Nov 19, 1998, and Dec 31, 2008, 8164 patients were randomly assigned to receive B vitamins (n=4089) or placebo (n=4075). Patients were followed up for a median duration of 3·4 years (IQR 2·0–5·5). 616 (15%) patients assigned to B vitamins and 678 (17%) assigned to placebo reached the primary endpoint (risk ratio [RR] 0·91, 95% CI 0·82 to 1·00, p=0·05; absolute risk reduction 1·56%, −0·01 to 3·16). There were no unexpected serious adverse reactions and no significant differences in common adverse effects between the treatment groups.InterpretationDaily administration of folic acid, vitamin B6, and vitamin B12 to patients with recent stroke or transient ischaemic attack was safe but did not seem to be more effective than placebo in reducing the incidence of major vascular events. These results do not support the use of B vitamins to prevent recurrent stroke. The results of ongoing trials and an individual patient data meta-analysis will add statistical power and precision to present estimates of the effect of B vitamins.FundingAustralia National Health and Medical Research Council, UK Medical Research Council, Singapore Biomedical Research Council, Singapore National Medical Research Council, Australia National Heart Foundation, Royal Perth Hospital Medical Research Foundation, and Health Department of Western Australia

Tracing the Total Stellar Mass and Star Formation of High-Redshift Protoclusters

As the progenitors of present-day galaxy clusters, protoclusters are excellent laboratories to study galaxy evolution. Since existing observations of protoclusters are limited to the detected constituent galaxies at UV and/or infrared wavelengths, the details of how typical galaxies grow in these young, pre-virialized structures remain uncertain. We measure the total stellar mass and star formation within protoclusters, including the contribution from faint undetected members by performing a stacking analysis of 211 $z=2-4$ protoclusters selected as Planck cold sources. We stack WISE and Herschel/SPIRE images to measure the angular size and the spectral energy distribution of the integrated light from the protoclusters. The fluxes of protoclusters selected as Planck cold sources can be contaminated by line of sight interlopers. Using the WebSky simulation, we estimate that a single protocluster contributes $33\pm15$% of the flux of a Planck cold source on average. After this correction, we obtain a total star formation rate of $7.3\pm3.2 \times 10^3\ M_{\odot} {\rm yr}^{-1}$and a total stellar mass of$4.9\pm 2.2\times 10^{12}\ M_{\odot}$. Our results indicate that protoclusters have, on average, 2x more star formation and 4x more stellar mass than the total contribution from individually-detected galaxies in spectroscopically-confirmed protoclusters. This suggests that much of the total flux within$z=2-4$protoclusters comes from galaxies with luminosities lower than the detection limit of SPIRE ($L_{IR} < 3 \times 10^{12} L_{\odot}$). Lastly, we find that protoclusters subtend a half-light radius of 2.8' (4.2-5.8 cMpc) which is consistent with simulations.Comment: Accepted for publication in Ap

Infanticide and infant defence by males--modelling the conditions in primate multi-male groups

Infanticide by primate males was considered rare if groups contain more than one adult male because, owing to lower paternity certainty, a male should be less likely to benefit from infanticide. Guided by recent evidence for strong variation of infanticide in primate multi-male groups, we modelled the conditions for when infanticide should occur for a group with a resident and an immigrant male. Setting the parameters (e.g. infant mortality, reduction of interbirth interval, life-time reproductive success, genetic representation) to fit the conditions most commonly found in nature, we develop a game-theoretic model to explore the influence of age and dominance on the occurrence of infanticide and infant defence. Male age strongly impacts the likelihood of an attack which is modified by the father's defence. If the new male is dominant he is likely to attack under most circumstances whereas a subordinate male will only attack if the father does not defend. These model scenarios fit the conditions under which infanticide is known to occur in primate multi-male groups and offer an explanation why infanticide is common in some multi-male groups and rare in others. Overall, the benefits for infanticidal males are strongly governed by a reduced interbirth interval while advantages via improved genetic representation in the gene pool contribute but a minor fraction

Hopf bifurcation in a gene regulatory network model:Molecular movement causes oscillations

Gene regulatory networks, i.e. DNA segments in a cell which interact with each other indirectly through their RNA and protein products, lie at the heart of many important intracellular signal transduction processes. In this paper we analyse a mathematical model of a canonical gene regulatory network consisting of a single negative feedback loop between a protein and its mRNA (e.g. the Hes1 transcription factor system). The model consists of two partial differential equations describing the spatio-temporal interactions between the protein and its mRNA in a 1-dimensional domain. Such intracellular negative feedback systems are known to exhibit oscillatory behaviour and this is the case for our model, shown initially via computational simulations. In order to investigate this behaviour more deeply, we next solve our system using Green's functions and then undertake a linearized stability analysis of the steady states of the model. Our results show that the diffusion coefficient of the protein/mRNA acts as a bifurcation parameter and gives rise to a Hopf bifurcation. This shows that the spatial movement of the mRNA and protein molecules alone is sufficient to cause the oscillations. This has implications for transcription factors such as p53, NF-$\kappa$B and heat shock proteins which are involved in regulating important cellular processes such as inflammation, meiosis, apoptosis and the heat shock response, and are linked to diseases such as arthritis and cancer